U.S. patent application number 15/568624 was filed with the patent office on 2018-11-08 for display apparatus and initial setting method for display apparatus.
This patent application is currently assigned to Sony Corporation. The applicant listed for this patent is Sony Corporation. Invention is credited to Akio Machida.
Application Number | 20180322845 15/568624 |
Document ID | / |
Family ID | 55858831 |
Filed Date | 2018-11-08 |
United States Patent
Application |
20180322845 |
Kind Code |
A1 |
Machida; Akio |
November 8, 2018 |
DISPLAY APPARATUS AND INITIAL SETTING METHOD FOR DISPLAY
APPARATUS
Abstract
A display device, a method, and a computer-readable medium. The
display device includes a layer including a first region and a
second region, wherein the first region and the second region are
configured to be visible to a user of the display device; and
circuitry configured: to control displaying a computer generated
image on an optical device overlapping the layer and to control a
first transmittance of the first region of the layer to be lower
than a second transmittance of the second region of the layer such
that: a visibility, through the first region, of the computer
generated image is increased and a visibility, through the second
region, of an environment opposite the user relative to the display
device is higher than a visibility, through the first region, of
the environment opposite the user relative to the display
device.
Inventors: |
Machida; Akio; (Kanagawa,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sony Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
Sony Corporation
Tokyo
JP
|
Family ID: |
55858831 |
Appl. No.: |
15/568624 |
Filed: |
April 15, 2016 |
PCT Filed: |
April 15, 2016 |
PCT NO: |
PCT/JP2016/002058 |
371 Date: |
October 23, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 2027/0118 20130101;
G02B 27/0172 20130101; G02F 1/155 20130101; G02B 27/017 20130101;
G09G 2340/0464 20130101; G09G 2360/144 20130101; G09G 2354/00
20130101; G09G 3/38 20130101; G02B 27/0101 20130101; G02B 2027/0125
20130101; G02B 26/026 20130101 |
International
Class: |
G09G 3/38 20060101
G09G003/38; G02B 27/01 20060101 G02B027/01; G02F 1/155 20060101
G02F001/155; G02F 1/15 20060101 G02F001/15 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 30, 2015 |
JP |
2015-092857 |
Claims
1. A display device comprising: a layer including a first region
and a second region, wherein the first region and the second region
are configured to be visible to a user of the display device; and
circuitry configured: to control displaying a computer generated
image on an optical device overlapping the layer and to control a
first transmittance of the first region of the layer to be lower
than a second transmittance of the second region of the layer such
that: a visibility, through the first region, of the computer
generated image is increased and a visibility, through the second
region, of an environment opposite the user relative to the display
device is higher than a visibility, through the first region, of
the environment opposite the user relative to the display
device.
2. The display device of claim 1, wherein: the display device
further comprises an input device configured to receive an input
from the user of the display device, and the circuitry is further
configured to determine, based on the input, whether the computer
generated image overlaps with the first region as viewed by the
user of the display device.
3. The display device of claim 1, further comprising: an input
device configured to receive an input from the user of the display
device and to adjust, based on the input, a position of the
computer generated image and/or a position of the first region.
4. The display device of claim 1, wherein: the display device
further comprises: an image forming device configured to emit
internal light based on which a computer generated image is formed;
a first substrate; a plurality of first transparent electrode
segments disposed on a surface of the first substrate, the layer
being disposed on a surface of the first transparent electrode
opposite the first substrate; a plurality of second transparent
electrode segments disposed on a surface of the layer opposite the
plurality of first transparent electrode segments; and a second
substrate disposed opposite the first substrate relative to the
layer, the plurality of first transparent electrode segments extend
in a first direction, and the plurality of second transparent
electrode segments extend in a second direction different from the
first direction.
5. The display device of claim 1, wherein: the layer comprises a
stack of electrochromatic material layers.
6. The display device of claim 5, wherein: the electrochromatic
material layers include: a first material layer comprising tungsten
trioxide, molybdenum trioxide, or vanadium pentoxide; a second
material layer comprising tantalum pentoxide; and a third material
layer comprising iridium tin oxide, iridium oxide, zirconium
dioxide, zirconium phosphate, or a Prussian blue complex.
7. The display device of claim 1, wherein: a ratio of a horizontal
length of the first region to a horizontal length of a computer
generated image region on which the computer generated image is
displayed is between 1 and 1.5, and a ratio of a vertical length of
the first region to a vertical length of the computer generated
image region is between 1 and 1.5.
8. The display device of claim 1, wherein: the circuitry is
configured to control the first transmittance of the first region
based on an illuminance of an environment surrounding the display
device.
9. The display device of claim 8, further comprising: a sensor
configured to measure the illuminance of the environment
surrounding the display device.
10. The display device of claim 1, wherein: the display device
comprises a head up display device.
11. The display device of claim 10, wherein: the head up display
device is configured to be installed on a windshield or a cockpit
of a vehicle.
12. The display device of claim 1, further comprising: a frame
configured to be mounted on a head of the user of the display
device.
13. The display device of claim 1, wherein: the circuitry is
configured to control a light shielding of the second region to be
equal to or less than 95% of a light shielding of the first
region.
14. The display device of claim 1, wherein: the circuitry is
configured to control a light shielding of the second region to be
equal to or less than 30% of a light shielding of the first
region.
15. The display device of claim 14, wherein: the circuitry is
configured to control a light shielding of the first region to be
between 35% and 99% of a complete light shielding of the first
region.
16. A method for controlling transmittance of a display device, the
method comprising: controlling a first transmittance of a first
region of a layer of the display device to be lower than a second
transmittance of a second region of the layer of the display device
such that: a visibility, through the first region, of a computer
generated image displayed on an optical device overlapping the
layer is increased and a visibility, through the second region, of
an environment opposite the user relative to the display device is
higher than a visibility, through the first region, of the
environment opposite the user relative to the display device,
wherein the first region and the second region are configured to be
visible to a user of the display device.
17. A computer-readable medium storing instructions that, when
executed by a computer, perform a method for controlling
transmittance of a display device, the method comprising:
controlling a first transmittance of a first region of a layer of
the display device to be lower than a second transmittance of a
second region of the layer of the display device such that: a
visibility, through the first region, of a computer generated image
displayed on an optical device overlapping the layer is increased
and a visibility, through the second region, of an environment
opposite the user relative to the display device is higher than a
visibility, through the first region, of the environment opposite
the user relative to the display device, wherein the first region
and the second region are configured to be visible to a user of the
display device.
18. The computer-readable medium of claim 17, wherein the method
further comprises: receiving an input from the user of the display
device; and determining, based on the input, whether the computer
generated image overlaps with the first region as viewed by the
user of the display device.
19. The computer-readable medium of claim 17, wherein the method
further comprises: receiving an input from the user of the display
device; and adjusting, based on the input, a position of the
computer generated image and/or a position of the first region.
20. The computer-readable medium of claim 17, wherein the method
further comprises: controlling the first transmittance of the first
region based on an illuminance of an environment surrounding the
display device.
21. The computer-readable medium of claim 20, wherein the method
further comprises: measuring the illuminance of the environment
surrounding the display device.
22. The computer-readable medium of claim 17, wherein the method
further comprises: controlling a light shielding of the second
region to be equal to or less than 95% of a light shielding of the
first region.
23. The computer-readable medium of claim 17, wherein the method
further comprises: controlling a light shielding of the second
region to be equal to or less than 30% of a light shielding of the
first region.
24. The computer-readable medium of claim 23, wherein the method
further comprises: controlling a light shielding ratio of the first
region to be between 35% and 99% of a complete light shielding of
the first region.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Japanese Priority
Patent Application JP 2015-092857 filed on Apr. 30, 2015, the
entire contents of which are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to a display apparatus, and
more particularly, to a display apparatus used for a head mounted
display (HMD) and an initial setting method for an associated
display apparatus.
BACKGROUND ART
[0003] In recent years, an augmented reality (AR) technique of
synthesizing and presenting virtual objects as additional
information or various types of information as electronic
information to a reality environment (or a portion thereof) has
drawn attention. In order to implement the augmented reality
technique, for example, a head mounted display as a device of
presenting visual information has been studied. In addition, as an
application field, work support in the reality environment is
expected, and for example, providing of road guidance information,
providing of technical information to a technician who performs
maintenance or the like, and the like may be exemplified.
Particularly, the head mounted display is very useful sine the
hands are not occupied. In addition, even in the case of obtaining
various types of information and the like when moving outdoors,
since various types of information or the like and an external
environment configured as a video or an image in sight can be
simultaneously recognized, smooth movement can be performed.
[0004] A virtual image display device (display apparatus) for
allowing an observer to observe a two-dimensional image formed by
an image forming device as an augmented virtual image by an virtual
image optical system is well known from, for example, JP
2006-162767 A.
[0005] As a conceptual view is illustrated in FIG. 30, an image
display device 100' is configured to include an image forming
device 111 which includes a plurality of pixels arranged in a
two-dimensional matrix shape, a collimator optical system 112 which
converts light emitted from the pixels of the image forming device
111 into parallel light, and an optical device 120 where the light
formed as the parallel light in the collimator optical system 112
is incident, guided, and emitted. The optical device 120 is
configured to include a light guide plate 121 where incident light
propagates an inner portion thereof by total reflection and, after
that, emits, a first deflecting unit 130 (for example, configured
with a single-layered light reflecting film) which reflects the
light incident on the light guide plate 121 so that the light
incident on the light guide plate 121 is totally reflected in the
inner portion of the light guide plate 121, and a second deflecting
unit 140 (for example, configured with a multi-layered light
reflecting film having a multilayer stacked structure) which allows
the light propagating the inner portion of the light guide plate
121 by total reflection to be emitted from the light guide plate
121. In addition, for example, if an HMD is configured with the
image display device 100', weight reduction and miniaturization of
the apparatus can be achieved. Furthermore, with respect to
reference numerals indicating other components in FIG. 30, the
image display device according to the first embodiment described
with reference to FIG. 1 is referred to.
[0006] Alternatively, a virtual image display device (display
apparatus) using a hologram diffraction grating for allowing an
observer to observe a two-dimensional image formed by an image
forming device as an augmented virtual image by a virtual image
optical system is well known from, for example, JP 2007-094175
A.
[0007] As a conceptual view is illustrated in FIG. 31, an image
display device 300' is configured to basically include an image
forming device 111 which displays an image, a collimator optical
system 112, and an optical device 320 where light displayed in the
image forming device 111 is incident and the light is guided to a
pupil 21 of an observer. Herein, the optical device 320 is
configured to include a light guide plate 321 and first and second
diffraction grating members 330 and 340 which are configured with
reflective volume hologram diffraction gratings installed on the
light guide plate 321. In addition, light emitted from pixels of
the image forming device 111 is incident on the collimator optical
system 112, and a plurality of parallel light having different
angles of incidence to the light guide plate 321 is generated by
the collimator optical system 112 to be incident on the light guide
plate 321. The parallel light is incident from a first surface 322
of the light guide plate 321 to be emitted. On the other hand, the
first and second diffraction grating members 330 and 340 are
attached to a second surface 323 of the light guide plate 321 which
is parallel to the first surface 322 of the light guide plate 321.
Furthermore, with respect to reference numerals indicating other
components in FIG. 31, the image display device according to the
third embodiment described with reference to FIG. 12 is referred
to.
[0008] In addition, in the image display devices 100' and 300', the
virtual image is formed based on the image, so that the observer
can view the image of the outside world and the formed virtual
image in an overlapped manner.
[0009] However, in a case where the surrounding environment where
the image display device 100' or 300' is placed is very bright or
according to contents of the formed virtual image, there may be a
problem in that sufficient contrast is not provided to the virtual
image observed by the observer. Therefore, a solution for solving
the problem, namely, a virtual image display device (display
apparatus) having a light regulating device is well known from, for
example, JP 2012-252091 A.
CITATION LIST
Patent Literature
[0010] PTL 1: JP 2006-162767 A [0011] PTL 2: JP 2007-094175 A
[0012] PTL 3: JP 2012-252091 A
SUMMARY
Technical Problem
[0013] Herein, the display apparatus is often demanded to allow the
observer using the display apparatus to safely behave in the
reality environment while securely recognizing the external
environment.
[0014] Therefore, a first object of the present disclosure is to
provide a display apparatus having configuration and structure
capable of providing high contrast to a virtual image observed by
an observer and capable of allowing the observer using the display
apparatus to safely behave in a reality environment while securely
recognizing an external environment. In addition, a second object
of the present disclosure is to provide an initial setting method
for an associated display apparatus.
Solution to Problem
[0015] A display device according to an embodiment of the present
disclosure includes: a layer including a first region and a second
region, wherein the first region and the second region are
configured to be visible to a user of the display device; and
circuitry configured: to control displaying a computer generated
image on an optical device overlapping the layer and to control a
first transmittance of the first region of the layer to be lower
than a second transmittance of the second region of the layer such
that: a visibility, through the first region, of the computer
generated image is increased and a visibility, through the second
region, of an environment opposite the user relative to the display
device is higher than a visibility, through the first region, of
the environment opposite the user relative to the display
device.
[0016] Alternatively or additionally, a method for controlling
transmittance of a display device comprises: controlling a first
transmittance of a first region of a layer of the display device to
be lower than a second transmittance of a second region of the
layer of the display device such that: a visibility, through the
first region, of a computer generated image displayed on an optical
device overlapping the layer is increased and a visibility, through
the second region, of an environment opposite the user relative to
the display device is higher than a visibility, through the first
region, of the environment opposite the user relative to the
display device, wherein the first region and the second region are
configured to be visible to a user of the display device.
[0017] Alternatively or additionally, a computer-readable medium
storing instructions that, when executed by a computer, perform a
method for controlling transmittance of a display device, and the
method comprises: controlling a first transmittance of a first
region of a layer of the display device to be lower than a second
transmittance of a second region of the layer of the display device
such that: a visibility, through the first region, of a computer
generated image displayed on an optical device overlapping the
layer is increased and a visibility, through the second region, of
an environment opposite the user relative to the display device is
higher than a visibility, through the first region, of the
environment opposite the user relative to the display device,
wherein the first region and the second region are configured to be
visible to a user of the display device.
Advantageous Effects of Invention
[0018] In the display apparatus according to an embodiment of the
present disclosure, when the virtual image is formed in a portion
of the virtual image forming region based on the light emitted from
the image forming device, since the light regulating device is
controlled so that the light shielding ratio of the virtual image
projection region of the light regulating device where the
projection image of the virtual image to the light regulating
device is included is higher than the light shielding ratio of the
other region of the light regulating device, high contrast can be
provided to the virtual image observed by the observer, and since
the high light shielding ratio region is narrow, the observer using
the display apparatus can securely and safely recognize the
external environment. In the initial setting method for the display
apparatus according to an embodiment of the present disclosure,
since the virtual image of the test pattern and the high light
shielding ratio region of the light regulating device are allowed
to be moved relative to each other so that the virtual image of the
test pattern observed by the observer and the high light shielding
ratio region of the light regulating device observed by the
observer overlap each other, for example, even in a case where the
observer using the display apparatus is replaced, initialization of
the position of the virtual image projection region of the light
regulating device where the projection image of the virtual image
to the light regulating device is included can be accurately
performed. Furthermore, the effect disclosed in this specification
is exemplary but not limited, and in addition, there may be
additional effects.
BRIEF DESCRIPTION OF DRAWINGS
[0019] FIG. 1 is a conceptual view of an image display device in a
display apparatus according to a first embodiment.
[0020] FIG. 2 is a schematic view as the display apparatus
according to the first embodiment or the like is viewed from the
upper side.
[0021] FIGS. 3A and 3B are a schematic view as the display
apparatus according to the first embodiment is viewed from the
lateral side and a schematic view as portions of an optical device
and a light regulating device in the display apparatus according to
the first embodiment are viewed from the front side,
respectively.
[0022] FIGS. 4A and 4B are a schematic cross-sectional view of the
light regulating device in the display apparatus according to the
first embodiment and a schematic front view of the optical device
and the light regulating device, respectively.
[0023] FIG. 5 is a view schematically illustrating a propagation
state of light in a light guide plate constituting an image display
device.
[0024] FIG. 6 is a conceptual view of a modification example of the
image display device in the display apparatus according to the
first embodiment.
[0025] FIG. 7 is a view illustrating an outside world viewed by an
observer.
[0026] FIGS. 8A and 8B are views illustrating states that the light
regulating device is controlled so that a light shielding ratio of
a virtual image projection region of the light regulating device
where a projection image of a virtual image to the light regulating
device is included is higher than the light shielding ratio of the
other region of the light regulating device.
[0027] FIGS. 9A to 9C are views schematically illustrating a change
or the like of the virtual image projection region of the light
regulating device.
[0028] FIG. 10 is a view schematically illustrating a virtual
rectangle circumscribing a virtual image formed in the optical
device and a rectangular shape of a virtual image projection region
of the light regulating device.
[0029] FIG. 11 is a conceptual view of an image display device in a
display apparatus according to a second embodiment.
[0030] FIG. 12 is a conceptual view of an image display device in a
display apparatus according to a third embodiment.
[0031] FIG. 13 is an enlarged schematic cross-sectional view
illustrating a portion of a reflective volume hologram diffraction
grating in the display apparatus according to the third
embodiment.
[0032] FIG. 14 is a conceptual view of an image display device in a
display apparatus according to a fourth embodiment.
[0033] FIG. 15 is a schematic view as a display apparatus according
to a fifth embodiment is viewed from the front side.
[0034] FIG. 16 is a schematic view as the display apparatus
according to the fifth embodiment is viewed from the upper
side.
[0035] FIG. 17 is a schematic view as a display apparatus according
to a sixth embodiment is viewed from the upper side.
[0036] FIGS. 18A and 18B are a schematic view as a display
apparatus according to a seventh embodiment is viewed from the
upper side and a schematic diagram of a circuit which controls an
illuminance sensor, respectively.
[0037] FIGS. 19A and 19B are a schematic view as a display
apparatus according to an eighth embodiment is viewed from the
upper side and a schematic diagram of a circuit which controls an
illuminance sensor, respectively.
[0038] FIG. 20 is a conceptual view of an image display device in a
display apparatus according to a ninth embodiment.
[0039] FIG. 21 is a schematic view as the display apparatus
according to the ninth embodiment is viewed from the upper
side.
[0040] FIG. 22 is a schematic view as the display apparatus
according to the ninth embodiment is viewed from the lateral
side.
[0041] FIG. 23 is a conceptual view of an image display device in a
modification example of the display apparatus according to the
ninth embodiment.
[0042] FIG. 24 is a conceptual view of an image display device in
another modification example of the display apparatus according to
the ninth embodiment.
[0043] FIG. 25 is a conceptual view of an image display device in
still another modification example of the display apparatus
according to the ninth embodiment.
[0044] FIGS. 26A and 26B are a view schematically illustrating a
state where a position of a virtual image projection region of a
light regulating device where a projection image of a virtual image
to the light regulating device is included is changed and a view
schematically illustrating a test pattern in a case where an
observer using the display apparatus is replaced in a twelfth
embodiment, respectively.
[0045] FIGS. 27A and 27B are schematic views as an optical device
in a modification example of the display apparatus according to the
sixth embodiment is viewed from the upper side.
[0046] FIGS. 28A and 28B are a schematic view as an optical device
in another modification example of the display apparatus according
to the sixth embodiment is viewed from the upper side and a
schematic view as the optical device is viewed from the lateral
side, respectively.
[0047] FIG. 29 is a conceptual view of an image display device in a
modification example of the display apparatus according to the
third and fourth embodiments.
[0048] FIG. 30 is a conceptual view of an image display device in a
display apparatus in the related art.
[0049] FIG. 31 is a conceptual view of an image display device in a
modification example of the display apparatus in the related
art.
DESCRIPTION OF EMBODIMENTS
[0050] Herein, the present disclosure will be described based on
embodiments with reference to the drawings, but the present
disclosure is not limited to the embodiment and various numeric
values and materials in the embodiment are exemplary ones.
Furthermore, the description will be made in the following
order.
[0051] 1. Overall Description of Display Apparatus According to
Present Disclosure and Initial Setting Method for Display Apparatus
According to Present Disclosure
[0052] 2. First Embodiment (Display Apparatus According to Present
Disclosure and Initial Setting Method for Display Apparatus
According to Present Disclosure)
[0053] 2. First Embodiment (Display Apparatus According to Present
Disclosure, First-A-Structure Optical Device, First-Configuration
Image Forming Device)
[0054] 3. Second Embodiment (Modification of Display Apparatus
According to First Embodiment, First-A-Structure Optical Device,
Second-Configuration Image Forming Device)
[0055] 4. Third Embodiment (Another Modification of Display
Apparatus According to First Embodiment, First-B-Structure Optical
Device, First-Configuration Image Forming Device)
[0056] 5. Fourth Embodiment (Still Another Modification of Display
Apparatus According to First Embodiment, First-B-Structure Optical
Device, Second-Configuration Image Forming Device)
[0057] 6. Fifth Embodiment (Modification of First to Fourth
Embodiment)
[0058] 7. Sixth Embodiment (Another Modification of First to Fourth
Embodiment, Second-Structure Optical Device, Second-Configuration
Image Forming Device)
[0059] 8. Seventh Embodiment (Modification of First to Sixth
Embodiment)
[0060] 9. Eighth Embodiment (Another Modification of First to Sixth
Embodiment)
[0061] 10. Ninth Embodiment (Modification of First to Eighth
Embodiment)
[0062] 11. Tenth Embodiment (Modification of First to Ninth
Embodiment)
[0063] 12. Eleventh Embodiment (Modification of Tenth
Embodiment)
[0064] 13. Twelfth Embodiment (Initial Setting Method for Display
Apparatus According to Present Disclosure)
[0065] 14. Others
[0066] <Overall Description of Display Apparatus According to
Present Disclosure and Initial Setting Method for Display Apparatus
According to Present Disclosure>
[0067] In a display apparatus according to an embodiment of the
present disclosure, a "projection image of a virtual image to a
light regulating device" specifically denotes a projection image
(that is, background of a virtual image) of a virtual image to the
light regulating device when an observer views the virtual image
(that is, when the pupil of the observer is used as a reference).
In an initial setting method for the display apparatus according to
an embodiment of the present disclosure, a test pattern may
basically have an arbitrary shape, and, specifically, for example,
characters or symbols displayed in a central portion and four
corners of a virtual image forming region of an optical device may
be exemplified. In addition, a virtual image of the test pattern
and a high light shielding ratio region of the light regulating
device are allowed to be moved relative to each other.
Specifically, an image signal of the test pattern may be processed
so that a position of the virtual image of the test pattern in the
optical device can be moved in units of pixel, a high light
shielding ratio region of the light regulating device may be
processed to be moved by using a light shielding ratio varying
minimum unit region (described later) of the light regulating
device as a movement unit, or a combination of these processes may
be used. In order to move the virtual image of the test pattern and
the high light shielding ratio region of the light regulating
device relative to each other, the observer may manually perform
manipulation. Specifically, the observer may manually perform by
manipulating a switch, a button, a dial, a slider, a knob, and the
like. The relative movement includes movement in the X-axis
direction, movement in the Y-axis direction, rotational movement,
expansion, reduction, and deformation, described later. In the
light regulating device, the position of the virtual image
projection region is not fixed but it is changed depending on the
position of the virtual image, and in addition, the number of
virtual image projection regions is also changed depending on the
number of virtual images.
[0068] In some embodiment, in the initial setting method for the
display apparatus according to an embodiment of the present
disclosure, as a reference of a movement amount when the virtual
image of the test pattern and the high light shielding ratio region
of the light regulating device are moved relative to each other,
the position relationship between the formation position of the
virtual image in the optical device and the position of the virtual
image projection region of the light regulating device may be
configured to be corrected. Specifically, the position relationship
between the formation position of the virtual image in the optical
device and the position of the virtual image projection region of
the light regulating device may be corrected based on a processed
amount of the image signal when the image signal of the test
pattern is processed so that the position of the virtual image of
the test pattern in the optical device is moved in units of a
pixel, based on a process of moving the high light shielding ratio
region of the light regulating device by using the minimum unit
region as a unit of movement, or based on a combination of these
processes. Namely, the formation position of the virtual image in
the optical device may be fixed and the position of the virtual
image projection region of the light regulating device may be
moved; the position of the virtual image projection region of the
light regulating device may be fixed and the formation position of
the virtual image in the optical device may be moved; or these
configurations may be combined.
[0069] In some embodiment, in the initial setting method for the
display apparatus according to an embodiment of the present
disclosure including the above-described preferred embodiment, in
addition, the light shielding ratio of the other region of the
light regulating device at the time of operation of the light
regulating device may be configured to be determined. Furthermore,
the light shielding ratio is a kind of an initial value determined
by the observer.
[0070] In addition, in some embodiment, in the initial setting
method for the display apparatus according to an embodiment of the
present disclosure including the above-described various preferred
embodiments, in addition, at the time of operation of the light
regulating device, the light shielding ratio of the virtual image
projection region of the light regulating device may be configured
to be determined. Furthermore, the light shielding ratio is a kind
of an initial value determined by the observer. In addition, the
value of the light shielding ratio may be constant, or as described
later, the value may be changed depending on illuminance of the
environment where the display apparatus is placed.
[0071] Moreover, in some embodiment, in the initial setting method
for the display apparatus according to an embodiment of the present
disclosure including the above-described various preferred
embodiments, in a case where a virtual rectangle circumscribing the
virtual image formed in the optical device is considered, when
lateral and longitudinal lengths of the virtual rectangle are
denoted by L.sub.1-T and L.sub.1-L, respectively, and when the
shape of the virtual image projection region of the light
regulating device is defined as a shape of a rectangle having
lateral and longitudinal lengths of L.sub.2-T and L.sub.2-L, a
value of L.sub.2-T/L.sub.1-T and the L.sub.2-L/L.sub.1-L may also
be determined. The determination is performed by the observer.
[0072] In the display apparatus in the initial setting method for
the display apparatus according to an embodiment of the present
disclosure including the above-described various preferred
embodiments or the display apparatus according to an embodiment of
the present disclosure (hereinafter, in some cases, these are
collectively referred to as a "display apparatus or the like
according to an embodiment of the present disclosure"), at the time
of operation of the light regulating device, the light shielding
ratio of the other region of the light regulating device is
preferably, for example, 0.95 or less when the light shielding
ratio of the virtual image projection region of the light
regulating device where the projection image of the virtual image
to the light regulating device is included is defined to be "1".
Alternatively, the light shielding ratio of the other region of the
light regulating device is preferably, for example, 30% or
less.
[0073] In the display apparatus or the like according to an
embodiment of the present disclosure including the above-described
preferred embodiments, at the time of operation of the light
regulating device, the light shielding ratio of the virtual image
projection region of the light regulating device is preferably, for
example, in a range of 35% to 99%. The light shielding ratio of the
virtual image projection region may be constant or may be changed
depending on the illuminance of the environment where the display
apparatus is placed. In some embodiment, in the latter case, the
light shielding ratio of the virtual image projection region may be
changed by observer's manipulation, or as described later, the
display apparatus may include further an illuminance sensor
(environment illuminance measurement sensor) which measures the
illuminance of the environment where the display apparatus is
placed, so that the light shielding ratio of the light regulating
device may be configured to be controlled based on a measurement
result of the illuminance sensor (environment illuminance
measurement sensor).
[0074] Moreover, in some embodiment, in the display apparatus or
the like according to an embodiment of the present disclosure
including the above-described various preferred embodiments, before
the virtual image is formed in the optical device based on the
light emitted from the image forming device, the light shielding
ratio of the virtual image projection region of the light
regulating device may be increased. As a time after the light
shielding ratio of the virtual image projection region of the light
regulating device is increased until the virtual image is formed,
0.5 seconds to 30 seconds may be exemplified. However, the time is
not limited to the value. In this manner, since the observer can
recognize in advance when and which position of the optical device
the virtual image is formed, visibility of the observer with
respect to the virtual image can be improved. In some embodiment,
the light shielding ratio of the virtual image projection region of
the light regulating device may be configured to be sequentially
increased as time elapses. Namely, a so-called fade-in state may be
configured.
[0075] Moreover, in some embodiment, in the display apparatus or
the like according to an embodiment of the present disclosure
including the above-described various preferred embodiments, in a
case where one virtual image in the optical device is formed based
on the light emitted from the image forming device and,
subsequently, a next virtual image different from the one virtual
image is formed, when the area of the virtual image projection
region of the light regulating device corresponding to the one
virtual image is denoted by S.sub.1 and the area of the virtual
image projection region of the light regulating device
corresponding to the next virtual image is denoted by S.sub.2,
[0076] in a case where S.sub.2/S.sub.1<0.8 or
1<S.sub.2/S.sub.1, the virtual image projection region of the
light regulating device where the next virtual image is formed may
be a region of the light regulating device where the projection
image of the next virtual image to the light regulating device is
included, and
[0077] in a case where 0.8.ltoreq.S.sub.2/S.sub.1.ltoreq.1, the
virtual image projection region of the light regulating device
where the next virtual image is formed may be a region of the light
regulating device where the projection image of the one virtual
image to the light regulating device is included. Namely, in some
embodiment, in the formation of the next virtual image from the
formation of the one virtual image, in a case where the area of the
virtual image projection region is decreased by 0% to 20%, the
virtual image projection region corresponding to the one virtual
image may be retained.
[0078] Moreover, in the display apparatus or the like according to
an embodiment of the present disclosure including the
above-described various preferred embodiments, when a virtual
rectangle circumscribing the virtual image formed in the optical
device is considered, the virtual image projection region of the
light regulating device may be configured to be larger than the
virtual rectangle. In addition, in this case, when lateral and
longitudinal lengths of the virtual rectangle circumscribing the
virtual image formed in the optical device are denoted by L.sub.1-T
and L.sub.1-L, respectively, and when the shape of the virtual
image projection region of the light regulating device is defined
as a shape of a rectangle having lateral and longitudinal lengths
of L.sub.2-T and L.sub.2-L, the following relationships are
preferably satisfied;
1.0.ltoreq.L.sub.2-T/L.sub.1-T.ltoreq.1.5
1.0.ltoreq.L.sub.2-L/L.sub.1-L.ltoreq.1.5
[0079] In a case where the virtual image is not formed, the light
shielding ratio of the entire light regulating device may be set to
have the same value as that of the light shielding ratio of the
other region of the light regulating device. When the forming of
the virtual image is ended and the virtual image disappears, the
light shielding ratio of the virtual image projection region of the
light regulating device where the projection image of the virtual
image to the light regulating device is included may be immediately
set to have the same value as that of the light shielding ratio of
the other region of the light regulating device. However, as time
elapses (for example, for 3 seconds), the light shielding ratio of
the virtual image projection region may be controlled to have the
same value as that of the light shielding ratio of the other region
of the light regulating device. Namely, a so-called fade-out state
may be configured.
[0080] Furthermore, the lateral direction and the longitudinal
direction denote a horizontal direction and a vertical direction,
respectively, or denote an X-axis direction and a Y-axis direction
described later, respectively. In general, in the case of forming a
virtual image configured with a character string in the optical
device, a region which is higher than a height (vertical direction
length or a Y-axis direction length) of the character string is set
as a region where the virtual image is to be formed. Specifically,
in the case of forming a virtual image configured with a plurality
of lines of character strings in the optical device, appropriate
line spacing is set. A sum of the number of pixels corresponding to
the line spacing (or, for example, the number of pixels
corresponding to 1/2, 1/3, or the like of the line spacing) and the
number of pixels corresponding to the height of the character
string may be set as a longitudinal length L.sub.1-L of the virtual
rectangle. In addition, in the case of forming a virtual image
configured with a character string in the optical device, there
exist gaps between characters. The value obtained by adding the
number of pixels which is an integer multiple of the number of
pixels corresponding to the gap to the left and right sides (or
front and back sides) of the number of pixels corresponding to the
character string may be set as a lateral length L.sub.1-T of the
virtual rectangle.
[0081] Moreover, in some embodiment, in the display apparatus or
the like according to an embodiment of the present disclosure
including the above-described various preferred embodiments, the
light regulating device may be configured to include
[0082] a first substrate,
[0083] a second substrate facing the first substrate,
[0084] a first transparent electrode installed on a facing surface
of the first substrate facing the second substrate,
[0085] a second transparent electrode installed on a facing surface
of the second substrate facing the first substrate, and
[0086] a light regulating layer interposed between the first
transparent electrode and the second transparent electrode. In
addition, in this case,
[0087] the first transparent electrode may be configured with a
plurality of strip-shaped first transparent electrode segments
extending in a first direction,
[0088] the second transparent electrode may be configured with a
plurality of strip-shaped second transparent electrode segments
extending in a second direction different from the first direction,
and
[0089] control of the light shielding ratio of a portion of the
light regulating device corresponding to an overlap region
(light-shielding-ratio-varying minimum unit region of the light
regulating device) between the first transparent electrode segments
and the second transparent electrode segments may be performed
based on control of voltages applied to the first transparent
electrode segments and the second transparent electrode segments.
Namely, the control of the light shielding ratio can be performed
based on a simple matrix scheme. The embodiment where the first
direction and the second direction are perpendicular to each other
may be exemplified.
[0090] Alternatively, in order to control the light shielding ratio
of the light-shielding-ratio-varying minimum unit region of the
light regulating device, a thin film transistor (TFT) may be
installed in each minimum unit region. Namely, the control of the
light shielding ratio may be controlled based on an active
matrix.
[0091] When the number of pixels in the lateral direction of the
virtual image forming region of the optical device is denoted by
M.sub.0 and the number of pixels in the longitudinal direction is
denoted by N.sub.0, the number of light-shielding-ratio-varying
minimum unit regions M.sub.1.times.N.sub.1 of the light regulating
device may be set so that M.sub.0=M.sub.1 and N.sub.0=N.sub.1, and
when M.sub.1/M.sub.0=k and N.sub.1/N.sub.0=k' (herein, k and k' are
positive integers), 1.1.ltoreq.k, preferably,
1.1.ltoreq.k.ltoreq.1.5, more preferably, 1.15.ltoreq.k.ltoreq.1.3
and 1.1.ltoreq.k', preferably, 1.1.ltoreq.k'.ltoreq.1.5, more
preferably, 1.15.ltoreq.k'.ltoreq.1.3 is satisfied. The value of k
and the value of k' may be equal to each other or may be different
from each other.
[0092] In some embodiment, in the display apparatus or the like
according to an embodiment of the present disclosure including the
above-described various preferred embodiments and configurations,
the frame may be configured to include a front portion disposed in
front of the observer, two temples rotatably attached to two ends
of the front portion through hinges, and a nose pads, and the light
regulating device may be arranged and installed in the front
portion. In addition, in some embodiment, the optical device may be
attached to the light regulating device. Furthermore, the optical
device may be attached to the light regulating device in a closely
contacted state or may be attached to the light regulating device
with a gap. Moreover, in some embodiment, in this case, the front
portion may have a rim, and the light regulating device may be
fitted to the rim. Alternatively, at least one of the first
substrate and the second substrate may be attached to, for example,
the frame. However, the present disclosure is not limited thereto.
In addition, in the display apparatus or the like according to an
embodiment of the present disclosure including the above-described
various preferred embodiments and configurations, the optical
device and the light regulating device may be arranged in this
order from the observer side, or the light regulating device and
the optical device may be arranged in this order.
[0093] In the display apparatus or the like according to an
embodiment of the present disclosure, the size and position of the
virtual image projection region of the light regulating device are
determined based on signals for displaying the image in the image
forming device. The size of the light regulating device may be
equal to, larger than, or smaller than that of the optical device.
The virtual image forming region may be positioned within the
projection image of the light regulating device. If the one of the
substrates constituting the light regulating device is also
configured as a member constituting the optical device, the total
weight of the display apparatus can be reduced, and there is no
problem in that the user of the display apparatus feels discomfort.
Furthermore, the other substrate is preferably configured to be
thinner than the one substrate.
[0094] Moreover, in some embodiment, in the display apparatus or
the like according to an embodiment of the present disclosure
including the above-described various preferred embodiments and
configurations, the optical device may be configured to include;
[0095] (b-1) a light guide plate where light incident from the
image forming device propagates an inner portion thereof by total
reflection and, after that, is emitted toward the observer, [0096]
(b-2) a first deflecting unit which deflects the light incident on
the light guide plate so that the light incident on the light guide
plate is totally reflected in the inner portion of the light guide
plate, and [0097] (b-3) a second deflecting unit which deflects the
light propagating the inner portion of the light guide plate by
total reflection several times in order to allow the light
propagating the inner portion of the light guide plate by total
reflection to be emitted from the light guide plate, and [0098] the
virtual image forming region of the optical device may be
configured with the second deflecting unit. Herein, the optical
device is, for the convenience, referred to as a "first-structure
optical device". Furthermore, the term "total reflection" denotes
total internal reflection or total reflection in an inner portion
of the light guide plate. The second deflecting unit (virtual image
forming region) is positioned within the projection image of the
light regulating device. In some embodiment, the second deflecting
unit or the first deflecting unit and the second deflecting unit
are configured to be covered with the one of the substrates
constituting the light regulating device.
[0099] In some embodiment, the display apparatus or the like
according to an embodiment of the present disclosure may be
configured to further include an illuminance sensor (environment
illuminance measurement sensor) which measures the illuminance of
the environment where the display apparatus is placed, so that the
light shielding ratio of the light regulating device may be
controlled based on a measurement result of the illuminance sensor
(environment illuminance measurement sensor). Alternatively, in
some embodiment, the display apparatus may be configured to further
include an illuminance sensor (environment illuminance measurement
sensor) which measures the illuminance of the environment where the
display apparatus is placed, so that luminance of the image formed
by the image forming device may be controlled based on a
measurement result of the illuminance sensor (environment
illuminance measurement sensor). A combination of these
configurations may be employed.
[0100] Alternatively, in some embodiment, the display apparatus may
be configured to further include a second illuminance sensor (for
the convenience, in some cases, referred to as a "transmitting
light illuminance measurement sensor") which measures the
illuminance based on the light passing from the external
environment through the light regulating device, so that the light
shielding ratio of the light regulating device may be controlled
based on a measurement result of the second illuminance sensor
(transmitting light illuminance measurement sensor). Alternatively,
in some embodiment, the display apparatus may configured to further
include a second illuminance sensor (transmitting light illuminance
measurement sensor) which measures the illuminance based on the
light passing from the external environment through the light
regulating device, so that the luminance of the image formed by the
image forming device may be controlled based on a measurement
result of the second illuminance sensor (transmitting light
illuminance measurement sensor). Furthermore, the second
illuminance sensor (transmitting light illuminance measurement
sensor) is preferably disposed to be closer to the observer side
than the optical device. At least two second illuminance sensors
(transmitting light illuminance measurement sensors) may be
disposed to perform measurement of illuminance based on the light
passing through a high light shielding ratio portion and
measurement of illuminance based on the light passing through a low
light shielding ratio portion. A combination of these
configurations may be employed. In addition, a combination of the
configuration and a configuration where control is performed based
on a measurement result of the illuminance sensor (environment
illuminance measurement sensor) may be employed.
[0101] The illuminance sensors (environment illuminance measurement
sensors and transmitting light illuminance measurement sensors) may
be configured with well-known illuminance sensors, and control of
the illuminance sensors may be performed based on a well-known
control circuit.
[0102] The highest light transmittance of the light regulating
device may be configured to be 50% or more, and the lowest light
transmittance of the light regulating device may be configured to
be 30% or less. Furthermore, as an upper limit value of the highest
light transmittance of the light regulating device, 99% may be
exemplified, and as a lower limit value of the lowest light
transmittance of the light regulating device, 1% may be
exemplified. Herein, there is a relationship of (light
transmittance)=1-(light shielding ratio).
[0103] In some cases, the light passing through the light
regulating device may be configured be colored in a desired color
by the light regulating device. In addition, in this case, in some
embodiment, the color colored by the light regulating device may be
configured to be variable. Alternatively, in some embodiment, the
color colored by the light regulating device may be configured to
be fixed. Furthermore, in the former case, in some embodiment, for
example, the light regulating device colored in red, the light
regulating device colored in green, and the light regulating device
colored in blue may be configured to be stacked. In addition, in
the latter case, although the color is not limited to the color
colored by the light regulating device, brown may be
exemplified.
[0104] In addition, in some cases, in some embodiment, the light
regulating device may be configured to be detachably arranged and
installed. In order to detachably arrange and install the light
regulating device, for example, the light regulating device may be
attached to, for example, the frame by using a screw made of a
transparent plastic. Alternatively, a groove may be cut in the
frame, and the light regulating device may be engaged with the
groove. Alternatively, a magnet may be attached to the frame, so
that the light regulating device may be attached to the frame. A
slide portion may be installed in the frame, and the light
regulating device may be fitted to the slide portion. In addition,
a connector may be attached to the light regulating device, and the
light regulating device may be electrically connected through the
connector and the wiring line to a control circuit (for example,
included in the control device for controlling the image forming
device) for controlling the light shielding ratio (light
transmittance) of the light regulating device. The light regulating
device may be configured to be curved.
[0105] In some embodiment, the light regulating device may be
configured with a light shutter using color change of a substance
generated by an oxidation/reduction reaction of an inorganic or
organic electrochromic material. Specifically, in some embodiment,
the light regulating layer may be configured to contain an
inorganic or organic electrochromic material. Moreover, in some
embodiment, the light regulating layer may be configured to have a
stacked structure of inorganic electrochromic material layers of
WO.sub.3 layer/Ta.sub.2O.sub.5 layer/Ir.sub.XSn.sub.1-XO layer from
the second transparent electrode side. Alternatively, in some
embodiment, the light regulating layer may be configured to have a
stacked structure of inorganic electrochromic material layers of
WO.sub.3 layer/Ta.sub.2O.sub.5 layer/IrO.sub.x layer. Instead of
the WO.sub.3 layer, an MoO.sub.3 layer or a V.sub.2O.sub.5 layer
may be used. In addition, instead of the IrO.sub.x layer, a
ZrO.sub.2 layer or a zirconium phosphate layer may be used.
Alternatively, prussian blue complex/nickel-substituted prussian
blue complex or the like may be used. As an organic electrochromic
material, for example, electrochromic materials disclosed in JP
2014-111710 A or JP 2014-159385 A may be used. Alternatively, in
some structure, a first transparent electrode and a second
transparent electrode are installed, and a first electrochromic
material layer and a second electrochromic material layer are
interposed between the first transparent electrode and the second
transparent electrode. The first electrochromic material layer is
configured with, for example, prussian blue complex, and the second
electrochromic material layer is configured with, for example,
nickel-substituted prussian blue complex.
[0106] Alternatively, in some embodiment, the light regulating
device may be a light shutter configured with an electrophoretic
dispersion liquid made of a number of charged electrophoretic
particles and a dispersion medium of which color is different from
the color of the electrophoretic particles or a light shutter
according to an electrodeposition method (electrodeposition
electric-field precipitation) utilizing an
electrodeposition/dissociation phenomenon occurring according to a
reversible oxidation/reduction reaction of metals (for example,
silver particles). Namely, the light regulating layer may also be
configured to contain an electrolyte containing metal ions.
Alternatively, a light shutter for controlling the light shielding
ratio (light transmittance) according to an electrowetting
phenomenon may be used. Moreover, the light regulating device may
be configured with a light shutter where the light regulating layer
is configured with a liquid crystal material layer. Specifically,
although a material constituting the light regulating layer is not
limited, a TN (twisted nematic) type liquid crystal material or an
STN (super twisted nematic) type liquid crystal material may be
exemplified.
[0107] Herein, the electrophoretic dispersion liquid is configured
to a number of charged electrophoretic particles and a dispersion
medium of which color is different from the color of the
electrophoretic particles. For example, in the case (a so-called
solid electrode configuration) where patterning is performed on the
first transparent electrode and patterning is not performed on the
second transparent electrode and in a case where the
electrophoretic particles are negatively charged, if a relatively
negative voltage is applied to the first transparent electrode and
a relatively positive voltage is applied to the second transparent
electrode, the negatively charged electrophoretic particles migrate
to cover the second transparent electrode. Therefore, the light
shielding ratio of the light regulating device has a high value. On
the other hand, on the contrary, if a relatively positive voltage
is applied to the first transparent electrode and a relatively
negative voltage is applied to the second transparent electrode,
the electrophoretic particles migrate to cover the first
transparent electrode. Therefore, the light shielding ratio of the
light regulating device has a low value. By appropriately
performing the voltage application to the transparent electrodes,
control of the light shielding ratio of the light regulating device
can be performed. The voltages may be a DC voltage or may be an AC
voltage. The shape of the patterned first transparent electrode may
be any shape capable of optimizing the value of the light shielding
ratio of the light regulating device when the electrophoretic
particles migrate to cover the first transparent electrode and the
light shielding ratio of the light regulating device has a low
value, and the shape may be determined by performing various tests.
As necessary, an insulating layer may be formed on the transparent
electrode. As a material constituting an associated insulating
layer, for example, a colorless transparent insulating resin may be
exemplified, and specifically, for example, an acrylic resin, an
epoxy resin, a fluorine resin, a silicon resin, a polyimide resin,
a polystyrene resin, and the like may be exemplified.
[0108] As a ratio of the electrophoretic particles with respect to
the dispersion liquid (dispersion medium) in the electrophoretic
dispersion liquid, 0.1 parts by mass to 15 parts by mass,
preferably, 1 part by mass to 10 parts by mass of the
electrophoretic particles with respect to the 100 parts by mass of
the dispersion liquid (dispersion medium) may be exemplified. As a
dispersion liquid (dispersion medium) which disperses the
electrophoretic particles, a highly-insulating, colorless
transparent liquid, specifically, a non-polar dispersion medium,
more specifically, an aliphatic hydrocarbon, an aromatic
hydrocarbon, a halogenated hydrocarbon, a silicon oil, and the like
may be exemplified. Herein, as an aliphatic hydrocarbon, pentane,
hexane, cyclohexane, heptane, octane, nonane, decane, dodecane,
ligroin, solvent naphtha, kerosene, normal paraffin, ISO paraffine,
and the like are exemplified. In addition, as an aromatic
hydrocarbon, benzene, toluene, xylene, alkyl benzene, and the like
are exemplified. As a silicon oil, various dimethyl polysiloxanes
including a modified silicone oil may be exemplified. More
specifically, Isopar G, H, L, M, EXXSOL D30, D40, D80, D110, D130
manufactured by Exxon Mobil Corporation, IP SOLVENT 1620, 2028,
2835 manufactured by Idemitsu Petrochemical Co., Ltd., Shellsol 70,
71, 72, A, AB manufactured by Shell Chemicals Japan Ltd.,
Nafutezoru L, M, H manufactured by Nippon Oil Co., Ltd., and the
like may be exemplified. Furthermore, these may be used alone or in
a combination of two or more types thereof.
[0109] A structure confining the electrophoretic dispersion liquid
in a microcapsule may be employed. The microcapsule can be obtained
by a well-known method such as an interfacial polymerization
method, an in-situ polymerization method, and a coacervation
method. A material constituting the microcapsule is demanded to
have a property of sufficiently transmitting the light, and thus,
specifically, a urea-formaldehyde resin, a melamine-formaldehyde
resin, a polyester resin, a polyurethane resin, a polyamide resin,
a polyethylene resin, a polystyrene resin, a polyvinyl alcohol
resin, gelatin, a copolymer thereof, and the like may be
exemplified. A method of arranging the microcapsule on the
substrate is not particularly limited. For example, an inkjet
method may be exemplified. Furthermore, for the purpose of
preventing a shift in position of the microcapsule arranged on the
substrate, the microcapsule may be fixed on the substrate by using
a light transmissive resin binder. As a light transmissive resin
binder, a water-soluble polymer, specifically, for example,
polyvinyl alcohol, polyurethane, polyester, an acrylic resin, a
silicone resin, and the like may be exemplified.
[0110] Although a charging control agent is not particularly
necessary to be used for the electrophoretic particles, in the case
of use a positive charging control agent in order to positively
charge the electrophoretic particles, as a positive charging
control agent, for example, nigrosine dyes such as Nigrosine Base
EX (Orient Chemical Industries Co., Ltd.), quaternary ammonium
salts such as P-51 (Orient Chemical Industries Co., Ltd.), Copy
Charge PXVP435 (manufactured by Hoechst Japan Ltd.), alkoxylated
amine, alkyl amide, molybdic acid chelate pigments, imidazole
compounds such as PLZ1001 (Shikoku Chemicals Corporation),
Transparent or white onium compounds, and the like may be
exemplified. Furthermore, as an onium compound, a primary to
quaternary onium compound can be freely selectable; an ammonium
compound, a sulfonium compound, or a phosphonium compound may be
selected; a substituent bonded to for example, nitrogen, sulfur, or
phosphorus atom is an alkyl group or an aryl group; as a salt, a
halogen element represented by chlorine or a hydroxy group, or a
carboxylic acid group is very suitable as a counter ion; but the
material is not limited thereto. Among them, primary to tertiary
amine salts or a quaternary ammonium salt are particularly
preferred. In case of using a negative charging control agent in
order to negatively charge the electrophoretic particles, as a
negative charging control agent, for example, a metal complex such
as BONTRON S-22, BONTRON S-34, BONTRON E-81, BONTRON E-84
(heretofore, manufactured by Orient Chemical Industries Co., Ltd.),
and Spiron Black TRH (manufactured by Hodogaya Chemical Co., Ltd.),
a quaternary ammonium salt such as a thioindigo pigment or Copy
Charge NXVP434 (manufactured by Hoechst Japan Ltd.), a calixarene
compound such as BONTRON E-89 (manufactured by Orient Chemical
Industries Co., Ltd.), a boron compound such as LR147 (manufactured
by Japan Carlit Co., Ltd.), a fluorine compound such as magnesium
fluoride or carbon fluoride, well-known metal soap such as aluminum
stearate, calcium stearate, aluminum lauric acid, barium lauric
acid, soda oleic acid, zirconium octylate, or cobalt naphthenate,
or a salicylic acid-based metal complex and a phenolic condensate
of an azine compound may be exemplified. As an addition amount of
the charging control agent, 100 parts by mass to 300 parts by mass
with respect to 100 parts by mass of the electrophoretic particles
may be exemplified.
[0111] As a dispersion liquid (dispersion medium) constituting the
electrophoretic dispersion liquid, nonionic surfactants such as
sorbitan fatty acid esters (for example, sorbitan monooleate,
sorbitan monolaurate, sorbitan sesquioleate, sorbitan trioleate, or
the like); polyoxyethylene sorbitan fatty acid esters (for example,
polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan
monooleate, or the like); polyethylene glycol fatty acid ester (for
example, polyoxyethylene monostearate, polyethylene glycol
diisostearate, or the like); polyoxyethylene alkyl phenyl ethers
(for example, polyoxyethylene nonylphenyl ether, polyoxyethylene
octyl phenyl ether, or the like); aliphatic diethanolamides; and
the like may be used. In addition, as a polymeric dispersant, for
example, a styrene-maleic acid resin, a styrene-acrylic resin, a
rosin, urethane polymer compound BYK-160, 162, 164, or 182
(manufactured by BYK Chemie), urethane-based dispersant EFKA-47,
LP-4050 (manufactured by EFKA Co.), polyester based polymer
compound Solsperse 24000 (manufactured by Zeneca), aliphatic
diethanolamide based polymer compound Solsperse 17000 (manufactured
by Zeneca), and the like may be exemplified. In addition, as other
polymeric dispersants, monomers such as lauryl methacrylate,
stearyl methacrylate, 2-ethylhexyl methacrylate, or cetyl
methacrylate capable of forming a portion of solvated in a
dispersion medium, monomers such as methyl methacrylate, ethyl
methacrylate, isopropyl methacrylate, styrene, or vinyl toluene
capable of forming a portion which is difficult to solvate in the
dispersion medium, a random copolymer of a monomer having a polar
functional group, a graft copolymer disclosed in JP 3-188469 A, and
the like may be exemplified. As a monomer having a polar functional
group, monomers such as acrylic acid, methacrylic acid, itaconic
acid, fumaric acid, maleic acid, styrene-sulfonic acid having an
acidic functional group; monomers such as dimethyl amino ethyl
methacrylate, diethylaminoethyl methacrylate, vinyl pyridine,
vinylpyrrolidine, vinyl piperidine, vinyl lactam having a basic
functional group; salts thereof; styrene-butadiene copolymers;
block copolymers of styrene and a long chain alkyl methacrylate as
disclosed in JP 60-10263 A; and the like may be exemplified. In
addition, the dispersant such as a graft copolymer disclosed in JP
3-188469 A may be added. As an addition amount of the dispersant,
0.01 parts by mass to 5 parts by mass with respect to 100 parts by
mass of the electrophoretic particles may be exemplified. In order
to further effectively generate the electrophoresis of the
electrophoretic particles, an ionic surfactant may be added. As a
specific example of the anionic surfactant, sodium dodecyl benzene
sulfonic acid, sodium dodecyl sulfate, sodium alkyl naphthalene
sulfonic acid, dialkylsulfosuccinic sodium succinate, and the like
may be exemplified. In addition, as a specific example of the
cationic surfactant, alkyl benzene dimethyl ammonium chloride,
alkyl trimethyl ammonium chloride, distearyl ammonium chloride, and
the like may be exemplified. In addition, a soluble ionic additive
may be added to a non-polar dispersion medium such as a
trifluorosulfonyl imide salt, a trifluoroacetate, a trifluoro
sulfate. As an added amount of the ionic additive, 1 part by mass
to 10 parts by mass with respect to 100 parts by mass of
electrophoretic particles may be exemplified.
[0112] As electrophoretic particles, carbon black (black), various
metal oxides, phthalocyanine dyes (cyan), direct blue 199 (project
cyan), magenta 377 (magenta), reactive red 29 (magenta), reactive
red 180 (magenta), and azo dyes (yellow, for example, yellow 104,
Ilford AG, Rue de l'Industrie, CH-1700 Fribourg, Switzerland) may
be exemplified.
[0113] In a case where the light regulating layer is configured
with an electrolyte layer containing metal ions, preferably, the
metal ions are silver ions, and the electrolyte contains at least
one type salt (referred to as a "supporting electrolyte salt")
selected from a group including LiX, NaX, and KX (herein, X is a
fluorine atom, a chlorine atom, a bromine atom, or an iodine
atom).
[0114] The electrolyte contains metal ions as a coloring material
which imparts color by electrochemical reduction/oxidation and
precipitation/dissolution associated with the reduction/oxidation.
In addition, by the electrochemical precipitation/dissolution
reaction for the metal ions, coloring and decoloring are made, so
that the light shielding ratio of the light regulating device is
changed. In other words, the operation of the light regulating
device in the display apparatus may be referred to as a so-called
operation of reversibly generating precipitation of a metal
according to electrolytic plating and elution reaction of the
precipitated metal. In this manner, as metal ions capable of
achieving coloring and decoloring by electrochemical
precipitation/dissolution, although not particularly limited,
besides the above-described ions of silver (Ag), ions of bismuth
(Bi), copper (Cu), sodium (Na), lithium (Li), iron (Fe), chromium
(Cr), nickel (Ni), cadmium (Cd) or a combination of these ions may
be exemplified, and among them, particularly preferred metal ions
are ions of silver (Ag) and ions of bismuth (Bi). With respect to
the silver or bismuth, a reversible reaction can be easily
processed, and moreover, a degree of discoloration at the time of
precipitation is high.
[0115] In addition, the metal ions are contained in the
electrolyte, and specifically, a material containing the metal ions
is dissolved in the electrolyte. More specifically, as a material
containing the metal ions, for example, at least one type of silver
halide such as AgF, AgCl, AgBr, and AgI, preferably, AgI or AgBr
may be exemplified, and a material containing the metal ions is
dissolved in the electrolyte. As a concentration of the silver
halide, for example, 0.03 to 2.0 mol/liter may be exemplified.
[0116] An electrolyte containing the metal ions is sealed between
the first substrate and the second substrate, and herein, the
electrolyte may be configured with an electrolytic solution or a
polymer electrolyte. Herein, as an electrolytic solution, a
material obtained by incorporating a metal salt or an alkyl
quaternary ammonium salt in a solvent may be used. Specifically, as
an electrolyte, water, ethyl alcohol, isopropyl alcohol,
2-ethoxyethanol, 2-methoxy ethanol, propylene carbonate, dimethyl
carbonate, ethylene carbonate, .gamma.-butyrolactone, acetonitrile,
sulfolane, dimethoxyethane, dimethylformamide (DMF),
diethylformamide (DEF), dimethyl sulfoxide (DMSO),
N,N-dimethylacetamide (DMAA), N-methyl propionic acid amide (MPA),
N-methyl pyrrolidone (MP), dioxolane (DOL), ethyl acetate (EA),
tetrahydrofuran (THF), methyltetrahydrofuran (MeTHF), or mixtures
thereof may be used. In addition, as a matrix (base material)
polymer used for a polymer electrolyte, a polymer material having a
repeating unit of alkylene oxide, alkyleneimine, or alkylene
sulfide in a main backbone unit, a side chain unit, or a main
backbone unit and a side chain unit, or a copolymer containing a
plurality of these different units may be exemplified.
Alternatively, a polymethyl methacrylate derivative, polyvinylidene
fluoride, polyvinylidene chloride, polyacrylonitrile, polycarbonate
derivative, or mixtures thereof may be exemplified. In a case where
the electrolyte is a polymer electrolyte, the electrolyte may be a
single layer or may have a stacked structure where a plurality of
polymer electrolyte layers is stacked.
[0117] A matrix polymer which is swollen by addition of water or an
organic solvent may also be used. Particularly, in a case where a
response speed or the like is demanded, by adding the water or the
organic solvent to the matrix polymer, the metal ions contained in
the electrolyte are allowed to be more easily moved.
[0118] Furthermore, in a case where hydrophilicity is demanded
according to characteristics of a matrix polymer or a desired
electrochemical reaction, water, ethyl alcohol, isopropyl alcohol,
or a mixture thereof is preferably added; and in a case where
hydrophobicity is demanded, propylene carbonate, dimethyl
carbonate, ethylene carbonate, .gamma.-butyrolactone, acetonitrile,
sulfolane, dimethoxyethane, ethyl alcohol, isopropyl alcohol,
dimethyl formamide, dimethyl sulfoxide, dimethylacetamide,
n-methylpyrrolidone, or a mixture thereof is preferably added.
[0119] As described above, coloring and decoloring of the light
regulating device (specifically, an electrodeposition type light
regulating device) occur according to the precipitation of the
metal on the second transparent electrode and the dissolution of
the metal in the electrolyte based on the voltage application to
the first transparent electrode and the second transparent
electrode. Herein, in general, the surface of the layer (metal
layer) made of metals precipitated on the second transparent
electrode which is in contact with the electrolyte becomes uneven
so that the surface appears to be blackish, and the surface of the
metal layer which is in contact with the second transparent
electrode becomes in a mirror surface shape. Therefore, in the case
of being used as a light regulating device, the surface of the
metal layer which is in contact with the electrolyte is preferably
configured to face the observer side. In other words, in some
embodiment, the first substrate is preferably configured to be
closer to the observer side than the second substrate.
[0120] As described above, a salt (supporting electrolyte salt)
containing ion species different from the metal ion species to be
precipitated or dissolved is added to the electrolyte, so that the
electrochemical precipitation/dissolution reaction can be more
effectively and stably performed. As a supporting electrolyte salt,
the above-described lithium salt, potassium salt, sodium salt, or
tetraalkyl quaternary ammonium salt may be exemplified. Herein, as
a lithium salt, specifically, LiCl, LiBr, LiI, LiBF.sub.4,
LiClO.sub.4, LiPF.sub.6, LiCF.sub.3SO.sub.3, and the like may be
exemplified. In addition, as a potassium salt, specifically, KCl,
KI, KBr, and the like may be exemplified. Furthermore, as a sodium
salt, specifically, NaCl, NaI, NaBr, and the like may be
exemplified. In addition, as a tetraalkyl quaternary ammonium salt,
specifically, a boric fluoride tetraethyl ammonium salt, a
perchloric acid tetraethyl ammonium salt, a boric
tetrabutylammonium fluoride salt, perchloric acid
tetrabutylammonium salt, a tetrabutyl ammonium halide salt, and the
like may be exemplified. Furthermore, the alkyl chain length of the
above-described quaternary ammonium salt may not be uniform. The
supporting electrolyte salt may be added with a concentration of,
for example, about 1/2 or 5 times of a concentration of a material
containing the metal ions. In addition, inorganic particles as a
colorant may be mixed with the electrolyte as a polymer
electrolyte.
[0121] In addition, in order to reversibly and efficiently perform
an electrochemical reaction, particularly,
precipitation/dissolution of metal, at least one of additives such
as a growth inhibitor, a stress inhibitor, a brightener, a
complexing agent, and a reducing agent may be added to the
electrolyte. As an additive, an organic compound containing a group
having an oxygen atom or a sulfur atom is preferred; and for
example, at least one type selected from a group including
thiourea, 1-allyl-2-thiourea, mercaptobenzimidazole, coumarin,
phthalic acid, succinic acid, salicylic acid, glycolic acid,
dimethyl amine borane (DMAB), trimethylamine borane (TMAB),
tartaric acid, oxalic acid and D-glucono-1,5-lactone may be
preferably added. Particularly, mercaptobenzimidazole analogous to
mercaptoalkyl imidazole is preferred because reversibility can be
improved and excellent effects can be obtained in terms of
long-term storage stability and high-temperature storage properties
by adding the mercaptobenzimidazole.
[0122] As a material constituting the transparent first substrate
and the transparent second substrate included in the light
regulating device, specifically, a transparent glass substrate such
as a soda lime glass or a white glass, a plastic substrate, a
plastic sheet, or a plastic film may be exemplified. Herein, as a
plastic, a cellulose ester such as polyethylene terephthalate,
polyethylene naphthalate, polycarbonate, or cellulose acetate, a
fluorine polymer such as a copolymer of polyvinylidene fluoride or
polytetrafluoroethylene and hexafluoropropylene, a polyether such
as polyoxymethylenem, a polyolefine such as polyacetal,
polystyrene, polyethylene, polypropylene, or pentene polymer, a
polyimide such as polyamide imide or polyether imide, a polyamide,
a polyether sulfone, a polyphenylene sulfide, a polyvinylidene
fluoride, a tetraacetyl cellulose, a brominated phenoxy, a
polyarylate, a polysulfone, and the like may be exemplified. The
plastic sheet and the plastic film may have a rigidity that the
sheet and the film are not easily bent or may have a flexibility.
In a case where the first substrate and the second substrate are
configured with a transparent plastic substrate, a barrier layer
made of an inorganic material or an organic material may be formed
on an inner surface of the substrate.
[0123] The first substrate and the second substrate are sealed and
adhered at an outer edge by a sealing member. As a sealing member
which is also referred as a sealing agent, various resins such as a
thermosetting resin, a light-curable resin, a moisture-curable
resin, or an anaerobic curable resin, for example, an epoxy resin,
a urethane based resin, an acrylic resin, a vinyl acetate resin, an
ene-thiol based resin, a silicone based resin, a modified polymer
resin, and the like may be used.
[0124] As a material constituting the first transparent electrode
and the second transparent electrode, specifically, an indium-tin
complex oxide (including indium tin oxide (ITO), Sn-doped
In.sub.2O.sub.3, a crystalline ITO, and an amorphous ITO),
fluroine-doped SnO.sub.2 (FTO), IFO (F-doped In.sub.2O.sub.3),
antimony-doped SnO.sub.2 (ATO), SnO.sub.2, ZnO (including Al-doped
ZnO or B-doped ZnO), an indium-zinc complex oxide (indium zinc
oxide (IZO)), a spinel type oxide, an oxide having a
YbFe.sub.2O.sub.4 structure, a conductive polymer such as
polyaniline, polypyrole, or polythiophene, and the like may be
exemplified, but the material is not limited thereto. In addition,
a combination of two or more types thereof may also be used. A
first auxiliary electrode (first bus electrode) and a second
auxiliary electrode (second bus electrode) of which plane shape is,
for example, a shape of a thin line may be installed on the first
transparent electrode and the second transparent electrode, and the
auxiliary electrodes may be configured with a metal such as gold,
silver, copper, aluminum, nickel, titanium or an alloy. Electric
resistances of the first auxiliary electrode and the second
auxiliary electrode need to be lower than those of the first
transparent electrode and the second transparent electrode. The
first transparent electrode, the second transparent electrode, the
first auxiliary electrode, and the second auxiliary electrode may
be formed based on a physical vapor deposition (PVD) method such as
a vacuum vapor deposition method or a sputtering method, various
chemical vapor deposition (CVD) methods, various coating methods,
or the like. Patterning of the auxiliary electrodes and the
transparent electrodes may be performed by an arbitrary method such
as an etching method, a lift-off method, or methods of using
various masks.
[0125] The optical device is of a semi-transparent type
(see-through type). Specifically, at least the portion of the
optical device facing the eye (pupil) of the observer is configured
to be semi-transparent (see-through), so that the observer can view
the outside scene through the portion of the optical deice and the
light regulating device. As described above, the observer observes
brightness of the light passing through the light regulating device
and the optical device, and the observer may manually control and
regulate the light shielding ratio by manipulating a switch, a
button, a dial, a slider, a knob, and the like. Alternatively, the
observer may control and regulate the light shielding ratio based
on a measurement result of the second illuminance sensor
(transmitting light illuminance measurement sensor) which measures
illuminance based on the light passing from the above-described
external environment through the light regulating device.
Furthermore, specifically, the control and regulation of the light
shielding ratio may be performed by controlling voltages applied to
the first transparent electrode and the second transparent
electrode. At least two second illuminance sensors (transmitting
light illuminance measurement sensors) are arranged, so that
measurement of illuminance based on the light passing through a
high light shielding ratio portion and measurement of illuminance
based on the light passing through a low light shielding ratio
portion may be performed. The display apparatus may include one
image display device or may include two image display devices. In a
case where the display apparatus includes two image display
devices, in the one light regulating device and the other light
regulating device, respectively, by regulating voltages applied to
the first transparent electrode and the second transparent
electrode, equalization of the light shielding ratio of the one
light regulating device and the light shielding ratio of the other
light regulating device can be achieved. The light shielding ratio
of the one light regulating device and the light shielding ratio of
the other light regulating device may be controlled, for example,
based on a measurement result of the second illuminance sensor
(transmitting light illuminance measurement sensor) which measures
illuminance based on the light passing from the above-described
external environment through the light regulating device.
Alternatively, the observer may observe brightness of the light
passing through the one light regulating device and the one optical
device and brightness of the light passing through the other light
regulating device and the other optical device, and the observer
may manually control and regulate the light shielding ratio by
manipulating a switch, a button, a dial, a slider, a knob, and the
like. In the case of performing the regulation of the light
shielding ratio, a test pattern may be configured to be indicated
in the optical device.
[0126] In this specification, in some cases, the term
"semi-transparent" is used, and the term does not denote that 1/2
(50%) of incident light is transmitted or reflected, but it denotes
that a portion of the incident light is transmitted and the
remaining portion is reflected.
[0127] As described above, in the first-structure optical device,
the first deflecting unit may be configured to reflect the light
incident on the light guide plate, and the second deflecting unit
may be configured to transmit and reflect the light propagating the
inner portion of the light guide plate by total reflection several
times. In addition, in this case, the first deflecting unit may be
configured to function as a reflecting mirror, and the second
deflecting unit may be configured to function as a semi-transparent
mirror. Furthermore, the first-structure optical device is, for the
convenience, referred to as a "first-A-structure optical
device".
[0128] In the first-A-structure optical device, the first
deflecting unit may be configured with, for example, a light
reflecting film (a kind of a mirror) which is made of a metal
including an alloy and reflects the light incident on the light
guide plate or a diffraction grating (for example, a hologram
diffraction grating film) which diffracts the light incident on the
light guide plate. Alternatively, the first deflecting unit may be
configured with, for example, a multi-layered stacked structure
where a plurality of dielectric stacked films is stacked, a
semi-transparent minor, or a polarizing beam splitter. In addition,
the second deflecting unit may be configured with a multi-layered
stacked structure where a plurality of dielectric stacked films is
stacked, a semi-transparent mirror, a polarizing beam splitter, or
a hologram diffraction grating film. In addition, the first
deflecting unit or the second deflecting unit is arranged and
installed in the inner portion of the light guide plate
(incorporated in the inner portion of the light guide plate), and
in the first deflecting unit, the parallel light incident on the
light guide plate is reflected or diffracted so that the parallel
light incident on the light guide plate is totally reflected in the
inner portion of the light guide plate. On the other hand, in the
second deflecting unit, the parallel light propagating the inner
portion of the light guide plate by total reflection is reflected
or diffracted several times and is emitted from the light guide
plate in a parallel light state.
[0129] Alternatively, the first deflecting unit may be configured
to diffract and reflect the light incident on the light guide
plate, and the second deflecting unit may be configured to diffract
and reflect the light propagating the inner portion of the light
guide plate by total reflection several times. In addition, in some
embodiment, in this case, the first deflecting unit and the second
deflecting unit may be configured with diffraction grating
elements. Moreover, the diffraction grating element is configured
as a reflective diffraction grating element or a transmissive
diffraction grating element. Alternatively, the one diffraction
grating element may be configured as a reflective diffraction
grating element, and the other diffraction grating element may be
configured as a transmissive diffraction grating element.
Furthermore, as a reflective diffraction grating element, a
reflective volume hologram diffraction grating may be exemplified.
In some cases, the first deflecting unit configured with a
reflective volume hologram diffraction grating is, for the
convenience, referred to as a "first diffraction grating member",
and the second deflecting unit configured with a reflective volume
hologram diffraction grating is, for the convenience, referred to
as a "second diffraction grating member". In addition, the
first-structure optical device is, for the convenience, referred to
as an "optical device having a first-B structure".
[0130] By the image display device in the present disclosure,
displaying of a monochrome (for example, green) image can be
performed. In addition, in this case, for example, an angle of view
may be divided, for example, by two (more specifically, for
example, two-equal division), and the first deflecting unit may be
configured by stacking two diffraction grating members
corresponding to two divided angles of view. Alternatively, in the
case of performing color image display, the first diffraction
grating member and the second diffraction grating member may be
configured by stacking P diffraction grating layers configured with
a reflective volume hologram diffraction grating in order to
correspond to diffraction and reflection of P types of light having
P different types (for example, P=3, three types of red, green, and
blue) of wavelength bands (or, wavelengths). An interference fringe
corresponding to one type of wavelength bands (or wavelengths) is
formed on each diffraction grating layer. Alternatively, P types of
interference fringe may be configured to be formed on the first
diffraction grating member or the second diffraction grating member
configured with one diffraction grating layer in order to
correspond to diffraction and reflection of P types of light having
P different types of wavelength bands (or wavelengths).
Alternatively, for example, in some structure, a diffraction
grating member configured with a diffraction grating layer made of
a reflective volume hologram diffraction grating which diffracts
and reflects the light having a red wavelength band (or wavelength)
may be arranged on the first light guide plate, a diffraction
grating member configured with a diffraction grating layer made of
a reflective volume hologram diffraction grating which diffracts
and reflects the light having a green wavelength band (or
wavelength) may be arranged on the second light guide plate, a
diffraction grating member configured with a diffraction grating
layer made of a reflective volume hologram diffraction grating
which diffracts and reflects the light having a blue wavelength
band (or wavelength) may be arranged on the third light guide
plate, and the first light guide plate, the second light guide
plate, and the third light guide plate are stacked with gaps.
Alternatively, the angle of view may be divided, for example, by
three, and the first diffraction grating member and the second
diffraction grating member may be configured by stacking
diffraction grating layers corresponding to the angles of view. In
addition, by employing these configurations, when the light having
each wavelength band (or wavelength) is diffracted and reflected in
the first diffraction grating member or the second diffraction
grating member, improvement of diffraction efficiency, an increase
of a diffraction acceptance angle, and optimization of a
diffraction angle can be achieved. A protection member is
preferably arranged so that the reflective volume hologram
diffraction grating is not in direct contact with the
atmosphere.
[0131] As a material constituting the first diffraction grating
member and the second diffraction grating member, a photopolymer
material may be exemplified. The constituent material or the basic
structure of the first diffraction grating member and the second
diffraction grating member configured with a reflective volume
hologram diffraction grating are preferably the same as those of a
reflective volume hologram diffraction grating in the related art.
The reflective volume hologram diffraction grating denotes a
hologram diffraction grating which diffracts and reflects only the
first-order diffraction light. The diffraction grating member is
configured so that interference fringe is formed over a range from
the inner portion to the surface thereof, and a method of forming
the associated interference fringe may be the same as the forming
method in the related art. Specifically, for example, a member (for
example, a photopolymer material) constituting the diffraction
grating member may be illuminated with object light from a
predetermined first direction of the one side; at the same time, a
member constituting the diffraction grating member may be
illuminated with reference light from a predetermined second
direction of the other side; and interference fringe formed by the
object light and the reference light may be recorded in the inner
portion of the member constituting the diffraction grating member.
By appropriately selecting the predetermined first direction, the
predetermined second direction, the wavelength of the object light,
and the wavelength of the reference light, a desired pitch of the
interference fringe and a desired inclination angle (slant angle)
of the interference fringe on the surface of the diffraction
grating member can be obtained. The inclination angle of the
interference fringe denotes an angle between the surface of the
diffraction grating member (or the diffraction grating layer) and
the interference fringe. In a case where the first diffraction
grating member and the second diffraction grating member are
configured as a stacked structure of P diffraction grating layers
made of a reflective volume hologram diffraction grating, the
stacking of the diffraction grating layers may be performed by
separately manufacturing P diffraction grating layers and, after
that, stacking (adhering) the P diffraction grating layers by
using, for example, a UV curable adhesive. In addition, the P
diffraction grating layers may be manufactured by manufacturing one
diffraction grating layer by using a photopolymer material having
adhesiveness, and after that, sequentially adhering photopolymer
materials having adhesiveness to manufacture the diffraction
grating layer.
[0132] Alternatively, in some embodiment, in the image display
device of the present disclosure, the optical device may be
configured with a semi-transparent mirror where the light emitted
from the image forming device is incident and is emitted toward the
pupil of the observer. In some embodiment, the optical device may
be configured with a polarizing beam splitter (PBS). The virtual
image forming region of the optical device is configured with a
semi-transparent mirror or a polarizing beam splitter. In some
structure, the light emitted from the image forming device may
propagate the air to be incident on the semi-transparent mirror or
the polarizing beam splitter. In some structure, for example, the
light may propagate the inner portion of a transparent member
(specifically, a member made of the same material as a material
constituting the light guide plate described later) such as a glass
plate or a plastic plate to be incident on the semi-transparent
mirror or the polarizing beam splitter. The semi-transparent mirror
or the polarizing beam splitter may be attached through the
transparent member to the image forming device, or the
semi-transparent mirror or the polarizing beam splitter may be
attached through a member different from the transparent member to
the image forming device. Herein, the optical device is, for the
convenience, referred to as a "second-structure optical device".
The semi-transparent mirror may be configured with a first
deflecting unit in the first-A-structure optical device, for
example, a metal including an alloy or may be configured with a
light reflecting film (a kind of a mirror) which reflects light or
a diffraction grating (for example, a hologram diffraction grating
film). Alternatively, in some embodiment, the optical device may be
configured with a prism where the light emitted from the image
forming device is incident and emitted toward a pupil of the
observer.
[0133] In some embodiment, in the image display device in the
present disclosure including the above-described various preferred
embodiments and configurations, the image forming device may be
configured to include a plurality of pixels arranged in a
two-dimensional matrix shape. Furthermore, the configuration of the
image forming device is, for the convenience, referred to as a
"first-configuration image forming device".
[0134] As a first-configuration image forming device, for example,
an image forming device configured with a reflective spatial light
modulation device and a light source, an image forming device
configured with a transmissive spatial light modulation device and
a light source, or an image forming device configured with a light
emitting element such as an organic Electro Luminescence (EL)
diode, an inorganic EL diode, a light emitting diode (LED), or a
semiconductor laser element may be exemplified. Among them, the
image forming device configured with a reflective spatial light
modulation device and a light source is preferred. As a spatial
light modulation device, a light valve, for example, a transmissive
or reflective liquid crystal display device such as an Liquid
Crystal On Silicon (LCOS), a digital micro mirror device (DMD) may
be exemplified, and as a light source, a light emitting element may
be exemplified. Moreover, the reflective spatial light modulation
device may be configured with a liquid crystal display device and a
polarizing beam splitter which reflects a portion of the light from
the light source to be guided to the liquid crystal display device
and which transmits a portion of the light reflected by the liquid
crystal display device to be guided to the optical system. As light
emitting elements constituting the light source, a red light
emitting element, a green light emitting element, a blue light
emitting element, and a white light emitting element may be
exemplified. Alternatively, white light may be obtained by
performing color-mixing and luminance equalization of red light,
green light, and blue light emitted from the red light emitting
element, the green light emitting element and the blue light
emitting element by using a light pipe. As a light emitting
element, for example, a semiconductor laser element, a solid laser,
or an LED may be exemplified. The number of pixels may be
determined based on the specification demanded for the image
display device, and as a specific value of the number of pixels,
320.times.240, 432.times.240, 640.times.480, 1024.times.768,
1920.times.1080, and the like may be exemplified.
[0135] Alternatively, in some embodiment, in the image display
device in the present disclosure including the above-described
various preferred embodiments and configurations, the image forming
device may be configured to include a light source and a scanning
unit which scans parallel light emitted from the light source.
Furthermore, the configuration of the image forming device is, for
the convenience, referred to as a "second-configuration image
forming device".
[0136] As a light source in the second-configuration image forming
device, a light emitting element may be exemplified, specifically,
a red light emitting element, a green light emitting element, a
blue light emitting element, and a white light emitting element may
be exemplified. Alternatively, white light may be obtained by
performing color-mixing and luminance equalization of red light,
green light, and blue light emitted from the red light emitting
element, the green light emitting element and the blue light
emitting element by using a light pipe. As a light emitting
element, for example, a semi-conductor laser element, a solid
laser, or an LED may be exemplified. The number of pixels (virtual
pixels) in the second-configuration image forming device may also
be determined based on the specification demanded for the image
display device, and as a specific value of the number of pixels
(virtual pixels), 320.times.240, 432.times.240, 640.times.480,
1024.times.768, 1920.times.1080, and the like may be exemplified.
In addition, in a case where color image display is performed and
the light source is configured with the red light emitting element,
the green light emitting element, and the blue light emitting
element, color combination is preferably performed by using, for
example, a cross prism. As a scanning unit, for example, a Micro
Electro Mechanical Systems (MEMS) or a galvano minor having a micro
minor being rotatable in two dimensional directions which can
perform horizontal scanning and vertical scanning with the light
emitted from the light source may be exemplified.
[0137] In the first-configuration image forming device or the
second-configuration image forming device of the image display
device including the first-structure optical device, the light
formed as a plurality of parallel light beams in the optical system
(optical system which converts the emitting light into the parallel
light, and in some cases, referred to as a "parallel light emitting
optical system", specifically, for example, a collimator optical
system or a relay optical system) is incident on the light guide
plate. This request for the parallel light is based on the fact
that, when the light is incident on the light guide plate, optical
wavefront information needs to be retained even after the light is
emitted through the first deflecting unit and the second deflecting
unit from the light guide plate. Furthermore, in order to generate
the plurality of parallel light beams, specifically, for example, a
light emitting unit of the image forming device may be positioned,
for example, at the point (position) of the focal length of the
parallel light emitting optical system. The parallel light emitting
optical system has a function of converting position information of
the pixels into angle information in the optical system of the
optical device. As a parallel light emitting optical system, an
optical system having a totally positive optical power where a
convex lens, a concave lens, a free-form surface prism, and a
hologram lens is used alone or in a combination manner may be
exemplified. A light shielding portion having an opening may be
disposed between the parallel light emitting optical system and the
light guide plate so that undesired light emitted from the parallel
light emitting optical system is not incident on the light guide
plate.
[0138] The light guide plate has two parallel surfaces (first and
second surfaces) being extended parallel to the axial line
(corresponding to the longitudinal direction, the horizontal
diction, and the X-axis direction) of the light guide plate.
Furthermore, the width direction (corresponding to the height
direction and the vertical direction) of the light guide plate
corresponds to the Y-axis direction. When the surface of the light
guide plate where the light is incident is denoted by a light guide
plate incident surface and the surface of the light guide plate
where the light is emitted is denoted by a light guide plate
emitting surface, the light guide plate incident surface and the
light guide plate emitting surface may be configured with the first
surface. Alternatively, the light guide plate incident surface may
be configured with the first surface, and the light guide plate
emitting surface may be configured with the second surface. The
interference fringe of the diffraction grating member is extended
substantially parallel to the Y-axis direction. As a material
constituting the light guide plate, a glass including a quartz
glass or an optical glass such as BK7 or a plastic material (for
example, PMMA, a polycarbonate resin, an acrylic resin, an
amorphous polypropylene based resin, or a styrene resin including
an AS resin) may be exemplified. The shape of the light guide plate
is not limited to the flat plate, but it may be a curved shape.
[0139] In the display apparatus or the like according to an
embodiment of the present disclosure, a light shielding member
blocking the incidence of external light to the optical device may
be configured to be arranged in the region of the optical device
where the light emitted from the image forming device is incident.
By arranging the light shielding member blocking the incidence of
external light to the optical device in the region of the optical
device where the light emitted from the image forming device is
incident, even though the light amount of incidence of the external
light is changed due to the operation of the light regulating
device, since the external light is not incident on the region of
the optical device where the light emitted from the image forming
device is incident, there is no problem in that the image display
quality of the display apparatus is deteriorated due to the
occurrence of undesired stray light. Furthermore, the region of the
optical device where the light emitted from the image forming
device is incident is preferably included within the projection
image of the light shielding member to the optical device.
[0140] The light shielding member may be configured to be disposed
at the side of the optical device opposite to the side where the
image forming device is disposed so as to be separated from the
optical device. In some embodiment, in the display apparatus having
the above configuration, the light shielding member may be
manufactured by using, for example, a non-transparent plastic
material. The light shielding member may be configured to
integrally extend from the housing of the image display device or
may be configured to be attached to the housing of the image
display device. The light shielding member may be configured to
integrally extend from the frame or may be configured to be
attached to the frame. Alternatively, the light shielding member
may be configured to be arranged in the portion of the optical
device of the side opposite to the side where the image forming
device is arranged. The light shielding member may also be
configured to be arranged in the light regulating device.
Furthermore, the light shielding member made of a non-transparent
material may be formed, for example, on the surface of the optical
device based on a physical vapor deposition (PVD) method or a
chemical vapor deposition (CVD) method, may be formed by a printing
method or like, or a film, a sheet, or a foil made of a
non-transparent material (plastic material or metal material, alloy
material, or the like) may be adhered. The projection image of the
end portion of the light regulating device to the optical device is
preferably included within the projection image of the light
shielding member to the optical device.
[0141] In the display apparatus or the like according to an
embodiment of the present disclosure, as described above, the frame
may be configured to include a front portion which is arranged in
front of the observer and two temples which are rotatably attached
to two ends of the front portion through hinges. Furthermore, an
earpiece is attached to a distal end of each temple. Although the
image display device is attached to the frame, specifically, for
example, the image forming device may be attached to the temple. In
addition, the front portion and the two temples may be integrally
configured. Namely, as the display apparatus or the like according
to an embodiment of the present disclosure is viewed overall, the
frame has substantially the same structure as that of typical
glasses. The material constituting the frame including pad portions
may be the same materials constituting typical glasses such as a
metal, an alloy, a plastic, or a combination thereof. Moreover,
nose pads may be configured to be attached to the front portion.
Namely, as the display apparatus or the like according to an
embodiment of the present disclosure is viewed overall, an assembly
of the frame (in some cases, including a rim) and the nose pads has
substantially the same structure as that of typical glasses. The
nose pads may also have well-known configuration and structure.
[0142] In addition, in some embodiment, in the display apparatus or
the like according to an embodiment of the present disclosure, in
terms of design or easiness of mounting, a wiring line (signal
line, power line, or the like) from one or two image forming
devices preferably passes through inner portions of the temple and
the earpiece and extends from the distal end of the earpiece to the
outside to be connected to the control device (control circuit or
control unit). Moreover, in some embodiment, each image forming
device may include a headphone unit, and a wiring line for
headphone unit from each image forming device may pass through the
inner portions of the temple and the earpiece and extends from the
distal end of the earpiece to the headphone unit. As a headphone
unit, for example, an inner-ear-type headphone unit and a
canal-type headphone unit may be exemplified. More specifically, in
some embodiment, the wiring line for headphone unit is preferably
configured to wrap from the distal end of the earpiece around the
back side of the pinna (auricle) and to extend to the headphone
unit. In addition, in some embodiment, an imaging device may be
attached to a central portion of the front portion. Specifically,
the imaging device is configured to include a solid state image
pickup element configured as, for example, a CCD sensor or a CMOS
sensor and a lens. A wiring line from the imaging device may be
connected, for example, through the front portion to the one image
display device (or image forming device). Moreover, the wiring line
may be included in the wiring line extending from the image display
device (or image forming device). The imaging device may be
attached to the central portion or the end portion of the frame or
may be attached to the temple.
[0143] Alternatively, in a case where the display apparatus or the
like according to an embodiment of the present disclosure is of a
binocular type, the light guide plate may be arranged at the side
closer to the center of the face of the observer than the image
forming device as viewed overall; a combining member which combines
two image display devices may further be included; the combining
member may be attached to the side of the central portion of the
frame being in contact with the observer which is positioned
between the two pupils of the observer; and the projection image of
the combining member may be included within the projection image of
the frame.
[0144] In this manner, due to the structure where the combining
member is attached to the central portion of the frame positioned
between the two pupils of the observer, namely, if there is no
structure where the image display device is directly attached to
the frame, when the observer mounts the frame on the head, the
temples are in an outwardly spread state, and as a result, even
though the frame is deformed, due to the deformation of the
associated frame, the displacement (positional change) of the image
forming device or the light guide plate does not occur, and even
though the displacement occurs, the displacement is negligible.
Therefore, it may be possible to securely prevent a convergence
angle of the left and right images from being changed. In addition,
since there is no need to increase a rigidity of the front portion
of the frame, an increase in weight of the frame, a deterioration
in design, and an increases in cost is not caused. In addition,
since the image display device is not directly attached to the
glasses-type frame, design, color, and the like of the frame can be
freely selected according to the preference of the observer, and
the constraints to the design of the frame are low, and the degree
of freedom in design is high. In addition, the combining member is
arranged between the observer and the frame, and the projection
image of the combining member is included within the projection
image of the frame. In other words, when the head mounted display
is viewed from the front side of the observer, the combining member
is hidden by the frame. Therefore, high quality in design and
design property can be provided to the head mounted display.
[0145] Furthermore, the combining member is preferably configured
to be attached to the side of the central portion (corresponding to
the bridge portion of typical glasses) of the front portion
positioned between the two pupils of the observer which is in
contact with the observer.
[0146] Although the two image display devices are combined by the
combining member, in some embodiment, specifically, the image
forming devices may be attached to the end portion of the combining
member so that the attachment state can be adjusted. In addition,
in this case, each image forming device is preferably configured to
be positioned at the side outer than the pupil of the observer.
Moreover, in this configuration, when the distance between the
center of the attached portion of the one image forming device and
the one end portion (the one endpiece) of the frame is denoted by
.alpha., the distance from the center of the combining member to
the one end portion (the one endpiece) of the frame is denoted by
.beta., the distance from the center of the attached portion of the
other image forming device and the one end portion (the one
endpiece) of the frame is denoted by .gamma., and the length of the
frame is denoted by L,
0.01.times.L.ltoreq..alpha..ltoreq.0.30.times.L, preferably,
0.05.times.L.ltoreq..alpha..ltoreq.0.25.times.L,
0.35.times.L.ltoreq..beta..ltoreq.0.65.times.L, preferably,
0.45.times.L.ltoreq..beta..ltoreq.0.55.times.L, and
0.70.times.L.ltoreq..gamma..ltoreq.0.99.times.L, preferably,
0.75.times.L.ltoreq..gamma..ltoreq.0.95.times.L are preferably
satisfied. With respect to the attachment of the image forming
devices to the end portion of the combining member, specifically,
for example, through-holes are formed at three positions of each
end portion of the combining member, threaded portions
corresponding to the through-holes are formed in the image forming
device, and the treaded portions formed in the image forming device
are screwed into the through-holes by screws. Springs are inserted
between the screws and the threaded portions. Therefore, according
to the tightening state of the screw, the attachment state of the
image forming device (inclination of the image forming device with
respect to the combining member) can be adjusted.
[0147] Herein, the center of the attached portion of the image
forming device denotes a bisection point in the axial direction of
the frame of the portion where the projection image of the image
forming device and the projection image of the frame which are
obtained by projecting the image forming device and the frame onto
a virtual plane overlap each other in the state that the image
forming device is attached to the combining member. In addition,
the center of the combining member denotes a bisection point in the
axial direction of the frame of the portion where the combining
member is in contact with the frame in the state that the combining
member is attached to the frame. In a case where the frame is
configured to be curved, the length of the frame is the length of
the projection image of the frame. Furthermore, the projection
direction is defined as a direction perpendicular to the face of
the observer.
[0148] Alternatively, although the two image display devices are
combined by the combining member, in some embodiment, specifically,
the two light guide plates may be combined by the combining member.
Furthermore, in some case, the two light guide plates may be
integrally manufactured, and in this case, although the combining
member is attached to the associated integrally-manufactured light
guide plate, the associated embodiment is also included in the
embodiment where the two light guide plates are combined by the
combining member. When the distance between the center of the one
image forming device and the one end portion of the frame is
denoted by .alpha.', and the distance between the center of the
other image forming device and the one end portion of the frame is
denoted by the .gamma.', the values of .alpha.' and .gamma.' are
preferably configured to be the same as the values of .alpha. and
.gamma. described above. Furthermore, the center of the image
forming device denotes a bisection point in the axial direction of
the frame of the portion where the projection image of the image
forming device and the projection image of the frame which are
obtained by projecting the image forming device and the frame on a
virtual plane overlap each other in the state that the image
forming device is attached to the light guide plate.
[0149] The shape of the combining member is not limited as long as
the projection image of the combining member is included within the
projection image of the frame, and the shape is basically
arbitrary. For example, a rod shape and an elongated plate shape
may be exemplified. As a material constituting the combining
member, a metal, an alloy, a plastic, or a combination thereof may
be exemplified.
[0150] In some embodiment, in the display apparatus or the like
according to an embodiment of the present disclosure, signals for
displaying the image in the image display device (signals for
forming the virtual image in the optical device) may be configured
to be received from the outside. In this embodiment, information or
data on the images which are to be displayed in the image display
device may be recorded, stored, and preserved, for example, in a
so-called clouding computer or a server, and by allowing the
display apparatus to include a communication unit, for example, a
mobile phone or a smart phone or by combining the display apparatus
and the communication unit, various types of information and data
are transmitted/received and exchanged between the clouding
computer or server and the display apparatus, and signals based on
the various types of information or data, namely, signals for
displaying the image in the image display device (signals for
forming the virtual image in the optical device) may be received.
Alternatively, in some embodiment, the signals for displaying the
image in the image display device (signals for forming the virtual
image in the optical device) may be stored in the display
apparatus. Furthermore, the images which are to be displayed in the
image display device include the various types of information and
the various types of data. Alternatively, the display apparatus may
include the imaging device, the image photographed by the imaging
device may be transmitted through the communication unit to the
clouding computer or the server, various types of information or
data corresponding to the image photographed by the imaging device
may be searched for in the clouding computer or the server, the
searched various types of information or data may be transmitted
through the communication unit to the display apparatus, and the
searched various types of information or data may be displayed as
images in the image display device.
[0151] When the image photographed by the imaging device is
transmitted through the communication unit to the clouding computer
or the server, the image photographed by the imaging device may be
displayed in the image display device and may be checked in the
optical device. In some embodiment, specifically, the outer edge of
the space region photographed by the imaging device may be
displayed in a frame shape in the light regulating device.
Alternatively, in some embodiment, the light shielding ratio of the
region of the light regulating device corresponding to the space
region photographed by the imaging device may be configured to be
higher than the light shielding ratio of the region of the light
regulating device corresponding to the outer side of the space
region photographed by the imaging device. In this embodiment, it
is viewed by the observer that the space region photographed by the
imaging device is darker than the outer side of the space region
photographed by the imaging device. Alternatively, in some
embodiment, the light shielding ratio of the region of the light
regulating device corresponding to the space region photographed by
the imaging device may be configured to be lower than the light
shielding ratio of the region of the light regulating device
corresponding to the outer side of the space region photographed by
the imaging device. In this embodiment, it is viewed by the
observer that the space region photographed by the imaging device
is brighter than the outer side of the space region photographed by
the imaging device. Therefore, the observer can easily and securely
recognize which position of the outside the imaging device is to
photograph.
[0152] The position of the region of the light regulating device
corresponding to the space region photographed by the imaging
device is preferably corrected. Specifically, by allowing the
display apparatus to include, for example, a mobile phone or a
smart phone or by combining the display apparatus and the mobile
phone, the smart phone, or the personal computer, the space region
photographed by the imaging device may be displayed in the mobile
phone, the smart phone, or the personal computer. In addition, in a
case where there is a difference between the space region displayed
in the mobile phone, the smart phone, or the personal computer and
the region of the light regulating device corresponding to the
space region photographed by the imaging device, by using the
control circuit (the mobile phone, the smart phone, or the personal
computer may be used as a substitute) for controlling the light
shielding ratio (light transmittance) of the light regulating
device, the region of the light regulating device corresponding to
the space region photographed by the imaging device may be
moved/rotated or magnified/reduced, so that the difference between
the space region displayed in the mobile phone, the smart phone, or
the personal computer and the region of the light regulating device
corresponding to the space region photographed by the imaging
device may be removed.
[0153] The display apparatus or the like according to an embodiment
of the present disclosure including the above-described various
modified examples may be used for, for example, reception and
display of an e-mail, display of various types of information or
the like in various sites on the Internet, display of various types
of description, symbols, signs, marks, emblems, designs, or the
like at the time of operation, manipulation, maintenance,
disassembly, or the like of observation objects such as various
devices; display of various types of description, symbols, signs,
marks, emblems, designs, or the like about observation objects of
persons, products, or the like; display of videos or still images;
display of subtitles of movies or the like; display of explanatory
text or closed caption on a video in synchronization with the
video; and display of explanatory text for explaining various
description of observation objects, the contents or the situation
of progression, background, or the like in Japanese traditional
plays, Kabuki, Noh, Noh farce, operas, concerts, ballets, various
plays, amusement parks, museums, tourist sites, pleasure resorts,
tourist guide, and the like or may be used for display of closed
caption. In the Japanese traditional plays, Kabuki, Noh, Noh farce,
operas, concerts, ballets, various plays, amusement parks, museums,
tourist sites, pleasure resorts, tourist guide, and the like,
characters may be displayed as images associated with the
observation objects in the display apparatus at an appropriate
timing. Specifically, for example, according to the situation of
progression of movies or the like or according to the situation of
progression of plays or the like, based on predetermined schedule
or time allocation by manipulation of an operator or under the
control of a computer or the like, an image control signal is
transmitted to the display apparatus, and the image is displayed in
the display apparatus. In addition, although the display of various
descriptions on the observation objects such as various devices,
persons, or products is performed, the observation objects such as
various devices, persons, or products may be photographed (imaged)
by the imaging device and the photographed (imaged) contents are
analyzed in the display apparatus, so that display of various
descriptions on observation objects such as various devices,
persons, or products which are produced in advance may be performed
in the display apparatus. Alternatively, the display apparatus or
the like according to an embodiment of the present disclosure may
also be used as a stereoscopic display apparatus. In this case, as
necessary, a polarizing plate or a polarizing film may be
detachably attached to the optical device, or a polarizing plate or
a polarizing film may be adhered to the optical device.
[0154] The image signals in the image forming device may include,
as well as the image signal (for example, character data), for
example, luminance data (luminance information) on the
to-be-displayed image, chromaticity data (chromaticity information)
thereof, or the luminance data and the chromaticity data. The
luminance data may be luminance data corresponding to the luminance
of a predetermined region including the observation objects which
are viewed through the optical device, and the chromaticity data
may be chromaticity data corresponding to the chromaticity of a
predetermined region including the observation objects which are
viewed through the optical device. In this manner, the luminance
data on the image is included, so that control of the luminance
(brightness) of the to-be-displayed image may be performed; the
chromaticity data on the image is included, so that control of the
chromaticity (color) of the to-be-displayed image may be performed;
and the luminance data and the chromaticity data on the image are
included, so that control of the luminance (brightness) and the
chromaticity (color) of the to-be-displayed image may be performed.
In the case of using the luminance data corresponding to the
luminance of the predetermined region including the observation
objects which are viewed through the image display device, the
value of the luminance data may be set so that, as the value of
luminance of the predetermined region including the observation
objects which are viewed through the image display device is
increased, the value of the luminance of the image is increased
(namely, the image is displayed to be brighter). In addition, in
the case of using the chromaticity data corresponding to the
chromaticity of the predetermined region including the observation
objects which are viewed through the image display device, the
value of the chromaticity data may be set so that the chromaticity
of the predetermined region including the observation objects which
are viewed through the image display device and the chromaticity of
the to-be-displayed image have a complementary color relationship
as a whole. The complementary colors denote a combination of colors
in the relation that the colors are positioned diametrically
opposite to each other in a hue circle (color circle). Green to
red, purple to yellow, orange to blue, and the like are
complementary colors. With respect to a color which is obtained by
mixing a different color to a certain color at an appropriate ratio
to decrease saturation such as white in case of light or black in
case of an object, complementarity of visual effects at the time of
parallel arrangement and complementarity at the time of mixing are
different. The complementary colors are also called complementary
colors, contrasting colors, or opposite colors. However, while the
complementary colors directly indicate opposed colors, in the
opposite colors, the indication range of the complementary colors
is slightly wide. The color combination of the complementary colors
provides a synergistic effect of allowing the colors to complement
each other, and thus, this is called complementary color
harmony.
[0155] For example, a head mounted display (HMD) may be configured
by using the display apparatus or the like according to an
embodiment of the present disclosure. In addition, therefore,
weight reduction and miniaturization of the display apparatus can
be achieved, discomfort at the time of mounting the display
apparatus can be greatly reduced, and moreover, the production cost
can be decreased. Alternatively, the display apparatus or the like
according to an embodiment of the present disclosure may be applied
to a head up display (HUD) installed in a cockpit of a vehicle or
an airplane. Specifically, in the HUD where the virtual image
forming region where the virtual image is formed based on the light
emitted from the image forming device is arranged in the windshield
of the vehicle of the cockpit or the like of the vehicle or the
airplane or in the HUD where a combiner having the virtual image
forming region where the virtual image is formed on the light
emitted from the image forming device is arranged in the windshield
of the vehicle of the cockpit or the like of the vehicle or the
airplane, the associated virtual image forming region or combiner
may be configured so as to overlap at least a portion of the light
regulating device.
First Embodiment
[0156] A first embodiment relates to the display apparatus
according to an embodiment of the present disclosure, and more
specifically, relates to a first-A-structure optical device and an
image forming device having a first configuration. A conceptual
view of the image display device in the first embodiment is
illustrated in FIG. 1. A schematic view as the display apparatus
(specifically, a head mounted display (HMD)) according to the first
embodiment or the like is viewed from the upper side is illustrated
in FIG. 2. A schematic view as the display apparatus is viewed from
the lateral side is illustrated in FIG. 3A. A schematic view as
portions of the optical device and a light regulating device are
viewed from the front side is illustrated in FIG. 3B. A schematic
cross-sectional view of the light regulating device in the display
apparatus according to the first embodiment and a front view of the
optical device and the light regulating device are illustrated in
FIGS. 4A and 4B. In addition, a propagation state of light in a
light guide plate constituting the image display device is
schematically illustrated in FIG. 5.
[0157] The display apparatus according to the first embodiment or
the later-described second to twelfth embodiments is, more
specifically, a head mounted display (HMD) and is configured to
include;
[0158] (A) a frame 10 (for example, a glasses-type frame 10) which
is mounted at the head of an observer 20,
[0159] (B) image display devices 100, 200, 300, 400, 500 which are
attached to the frame 10, and
[0160] (C) a light regulating device 700 which adjusts a light
amount of external light incident from the outside. Furthermore,
the display apparatus according to the first embodiment or the
later-described second to twelfth embodiments is, specifically,
configured as a binocular type having two image display devices,
but the display apparatus may be configured as a monocular type
having one image display device. In addition, image forming devices
111, 211 display, for example, a monochrome (for example, green)
image (virtual image). In addition, the image display devices 100,
200, 300, 400, 500 in the first embodiment or the later-described
second to twelfth embodiments are configured to include;
[0161] (a) image forming devices 111, 211, and
[0162] (b) optical devices 120, 320, 520 having a virtual image
forming region where a virtual image is formed based on light
emitted from the image forming devices 111, 211. In addition, the
display apparatus according to the first embodiment, the
later-described second to fifth embodiments, or the later-described
seventh to twelfth embodiments is configured to further
include;
[0163] (c) optical systems (parallel light emitting optical
systems) 112, 254 which convert light emitted from the image
forming devices 111, 211 into parallel light, so that the light
flux formed as the parallel light in the optical systems 112, 254
are incident to the optical devices 120, 320, 520 to be guided and
emitted.
[0164] Furthermore, the image display devices 100, 200, 300, 400,
500 may be fixedly attached to the frame 10 or may be detachably
attached to the frame. Herein, the optical systems 112, 254 is
disposed between the image forming devices 111, 211 and the optical
devices 120, 320, 520. In addition, the light flux formed as the
parallel light in the optical systems 112, 254 is incident to the
optical devices 120, 320, 520 to be guided and emitted. In
addition, the optical devices 120, 320, 520 are of a
semi-transparent type (see-through type). Specifically, at least
portions (more specifically, the later-described light guide plates
121, 321 and second deflecting units 140, 340) of the optical
device facing two eyes of the observer 20 are semi-transparent
(see-through).
[0165] Herein, the virtual image forming region of the optical
devices 120, 320, 520 overlap the light regulating device 700, the
light regulating device 700 is controlled so that, when the virtual
image is formed in a portion of the virtual image forming region
based on the light emitted from the image forming devices 111, 211,
the light shielding ratio of a virtual image projection region 711
of the light regulating device 700 where the projection image of
the virtual image to the light regulating device 700 is included is
higher than the light shielding ratio of the other region 712 of
the light regulating device 700. Furthermore, in the light
regulating device 700, the position of the virtual image projection
region 711 is not fixed but changed depending on the formation
position of the virtual image, and in addition, the number of
virtual image projection regions 711 is changed depending on the
number of virtual images (or the number of a series of virtual
image groups, the number of blocked virtual image groups, or the
like).
[0166] In the display apparatus according to the first embodiment
or the later-described second to fourth embodiments, the optical
devices 120, 320 is configured to include;
[0167] (b-1) light guide plates 121, 321 where light incident from
the image forming devices 111, 211 propagates an inner portion
thereof by total reflection and, after that, is emitted toward the
observer 20,
[0168] (b-2) first deflecting units 130, 330 which deflect the
light incident on the light guide plates 121, 321 so that the light
incident on the light guide plates 121, 321 is totally reflected in
the inner portion of the light guide plates 121, 321, and
[0169] (b-3) second deflecting units 140, 340 which deflect the
light propagating the inner portion of the light guide plates 121,
321 by total reflection several times in order to emit the light
propagating the inner portion of the light guide plates 121, 321 by
total reflection from the light guide plates 121, 321, and
[0170] the virtual image forming region of the optical device is
configured with the second deflecting units 140, 340.
[0171] In the first embodiment or the later-described second to
fourth embodiments, a point where the center incident light beam
perpendicularly incident on the optical devices 120, 320 among the
light beams (central light beams CL) being emitted from the center
of the image forming devices 111, 211 and passing through an
image-forming-device-side nodal point of the side of the optical
systems 112, 254 is incident on the optical devices 120, 320 is
denoted by an optical device central point O; an axial line passing
through the optical device central point O and being parallel to
the axial direction of the optical devices 120, 320 is denoted by
an X axis; and an axial line passing through the optical device
central point O and being coincident with the normal line of the
optical devices 120, 320 is denoted by a Z axis. Furthermore, the
central point of the first deflecting units 130, 330 described
below is the optical device central point O. Namely, as illustrated
in FIG. 5, in the image display devices 100, 200, 300, 400, the
center incident light beam CL being emitted from the center of the
image forming devices 111, 211 and passing through the
image-forming-device-side nodal point of the optical systems 112,
254 perpendicularly collides with the light guide plates 121, 321.
In other words, the center incident light beam CL is incident on
the light guide plates 121, 321 with an incident angle of 0 degree.
In addition, in this case, the center of the to-be-displayed image
(virtual image) is coincident with the vertical direction of first
surfaces 122, 322 of the light guide plates 121, 321.
[0172] In this manner, the first deflecting unit reflects the light
incident on the light guide plates 121, 321, and the second
deflecting unit transmits and reflects the light propagating the
inner portion of the light guide plates 121, 321 by total
reflection several times. Specifically, in the first embodiment or
the later-described second embodiment, the first deflecting unit
130 and the second deflecting unit 140 are arranged and installed
in the inner portion of the light guide plate 121. In addition, the
first deflecting unit 130 reflects the light incident on the light
guide plate 121, and the second deflecting unit 140 transmits and
reflects the light propagating the inner portion of the light guide
plate 121 by total reflection several times. Namely, the first
deflecting unit 130 functions as a reflecting mirror, and the
second deflecting unit 140 functions as a semi-transparent mirror.
More specifically, the first deflecting unit 130 installed in the
light guide plate 121 is configured with a light reflecting film (a
kind of a minor) which is made of aluminum (Al) to reflect the
light incident on the light guide plate 121. On the other hand, the
second deflecting unit 140 installed in the light guide plate 121
is configured with a multi-layered stacked structure where a number
of dielectric stacked films are stacked. The dielectric stacked
film is configured with, for example, a TiO.sub.2 film as a high
dielectric constant material and an SiO.sub.2 film as a low
dielectric constant material. A multi-layered stacked structure
where a number of dielectric stacked films is stacked is disclosed
in JP 2005-521099 A. Although the six-layered dielectric stacked
film is illustrated in the drawings, the present disclosure is not
limited thereto. A thin piece made of the same material as the
material constituting the light guide plate 121 is interposed
between the dielectric stacked films. Furthermore, in the first
deflecting unit 130, the parallel light incident on the light guide
plate 121 is reflected (or diffracted) so that the parallel light
incident on the light guide plate 121 is totally reflected inside
the light guide plate 121. On the other hand, in the second
deflecting unit 140, the parallel light propagating the inner
portion of the light guide plate 121 by total reflection is
reflected (or diffracted) several times and is emitted from the
light guide plate 121 toward a pupil 21 of the observer 20 in a
parallel light state.
[0173] With respect to the first deflecting unit 130, by cutting a
portion 124 where the first deflecting unit 130 of the light guide
plate 121 is installed, a slanted surface where the first
deflecting unit 130 is to be formed may be installed in the light
guide plate 121, a light reflecting film may be vapor-deposited on
the associated slanted surface, and after that, the cut portion 124
of the light guide plate 121 may be adhered to the first deflecting
unit 130. In addition, with respect to the second deflecting unit
140, a multi-layered stacked structure may be manufactured by
stacking a number of dielectric stacked films (for example, formed
by a vapor deposition method) and the same material (for example, a
glass) as the material constituting the light guide plate 121; a
slanted surface may be formed by cutting a portion 125 of the light
guide plate 121 where the second deflecting unit 140 is to be
installed; the multi-layered stacked structure may be adhered to
the associated slanted surface; and outer appearance may be
arranged properly by performing polishing or the like. Therefore,
the optical device 120 where the first deflecting unit 130 and the
second deflecting unit 140 are installed in the inner portion of
the light guide plate 121 can be obtained.
[0174] Herein, in the first embodiment, the later-described second
to fourth embodiments, or the later-described seventh to twelfth
embodiments, the light guide plates 121, 321 made of an optical
glass or a plastic material has two parallel surfaces (first
surfaces 122, 322 and second surfaces 123, 323) which extend in
parallel to the light propagating direction (X axis) by total
internal reflection of the light guide plates 121, 321. The first
surfaces 122, 322 and the second surfaces 123, 323 face each other.
In addition, the parallel light is incident from the first surfaces
122, 322 corresponding to the light incident surface and propagates
the inner portion by total reflection, and after that, is emitted
from the first surfaces 122, 322 corresponding to the light
emitting surface. However, the present disclosure is not limited
thereto, but the light incident surface may be configured with the
second surfaces 123, 323, and the light emitting surface may be
configured with the first surfaces 122, 322.
[0175] In the first embodiment or the later-described third
embodiment, the image forming device 111 is a first-configuration
image forming device and includes a plurality of pixels which are
arranged in a two-dimensional matrix shape. Specifically, the image
forming device 111 is configured to include a reflective spatial
light modulation device 150 and a light source 153 configured with
a light emitting diode which emits white light. The entire image
forming devices 111 can be accommodated in a housing 113 (in FIG.
1, indicated by a dashed-dotted line), an opening (not shown) is
installed in the associated housing 113, and light is emitted
through the opening from the optical system (parallel light
emitting optical system, collimator optical system) 112. The
reflective spatial light modulation device 150 is configured to
include a liquid crystal display device (LCD) 151 configured with
an LCOS as a light valve and a polarizing beam splitter 152 which
reflect a portion of the light from the light source 153 to be
guided to the liquid crystal display device 151 and transmits a
portion of the light reflected by the liquid crystal display device
151 to be guided to the optical system 112. The liquid crystal
display device 151 includes a plurality (for example,
640.times.480) of pixels (liquid crystal cells) which are arranged
in a two-dimensional matrix shape. The polarizing beam splitter 152
has well-known configuration and structure. Nonpolarized light
emitted from the light source 153 collides with the polarizing beam
splitter 152. In the polarizing beam splitter 152, P polarization
components are transmitted to be emitted to the outside of the
system. On the other hand, S polarization components are reflected
on the polarizing beam splitter 152 to be incident on the liquid
crystal display device 151 and are reflected in an inner portion of
the liquid crystal display device 151 to be emitted from the liquid
crystal display device 151. Herein, among the light emitted from
the liquid crystal display device 151, the light emitted from the
pixels displaying "white" includes a large amount of the P
polarization components, and the light emitted from the pixels
displaying "black" includes a large amount of the S polarization
component. Therefore, among the light emitted from the liquid
crystal display device 151 and colliding with the polarizing beam
splitter 152, the P polarization components pass through the
polarizing beam splitter 152 to be guided to the optical system
112. On the other hand, the S polarization components are reflected
on the polarizing beam splitter 152 to be returned to the light
source 153. The optical system 112 is configured with, for example,
a convex lens, and the image forming device 111 (more specifically,
the liquid crystal display device 151) is arranged at the point
(position) of the focal length of the optical system 112 in order
to generate the parallel light.
[0176] The frame 10 is configured to include a front portion 11
arranged in front of the observer 20, two temples 13 rotatably
attached to two ends of the front portion 11 through hinges 12, and
earpieces (in some cases, referred to as ear covers, earmuffs, or
ear pads) 14 attached to distal end portions of the temples 13. In
addition, nose pads (not shown in FIG. 2) are attached. Namely,
basically, an assembly of the frame 10 and the nose pads has
substantially the same structure as that of typical glasses.
Moreover, each housing 113 is detachably attached to the temple 13
by an installation member 19. The frame 10 is manufactured by using
a metal or a plastic. Furthermore, each of housing 113 may be
attached to the temple 13 by the installation member 19 so as not
to be detached. In addition, in the case of an observer who owns
and mounts glasses, each housing 113 may be detachably attached to
the temple 13 of the frame 10 of the glasses owned by the observer
by the installation member 19. Each housing 113 may be attached to
the outer side of the temple 13 or may be attached to the inner
side of the temple 13. Alternatively, the light regulating device
700 and the light guide plates 121, 321 may be fitted to the rim
installed in the front portion 11, the light regulating device 700
may be fitted, and the light guide plates 121, 321 may be
fitted.
[0177] Moreover, a wiring line (signal line, power line, or the
like) 15 extending from the one image forming device 111A passes
through the inner portions of the temple 13 and the earpiece 14 and
extends from the distal end portion of the earpiece 14 to the
outside to be connected to a control device (control circuit or
control unit) 18. Moreover, each of image forming devices 111A and
111B includes a headphone unit 16, and a wiring line for headphone
unit 16' extending from each of the image forming devices 111A and
111B passes through the inner portions of the temple 13 and the
earpiece 14 and extends from the distal end portion of the earpiece
14 to the headphone unit 16. More specifically, the wiring line for
headphone unit 16' wraps from the distal end portion of the
earpiece 14 around the back side of the pinna (auricle) and extends
to the headphone unit 16. By this configuration, a neat display
apparatus can be formed not to give an impression that the
headphone unit 16 or the wiring line for headphone unit 16' is
arranged disorderly.
[0178] As described above, the wiring lines (signal lines, power
lines, and the like) 15 are connected to the control device
(control circuit) 18. The control device 18 includes, for example,
an image information storage device 18A. In addition, in the
control device 18, a process for image display is performed. The
control device 18 and the image information storage device 18A may
be configured with a well-known circuit.
[0179] An imaging device 17 configured with a solid state imaging
element configured as a CCD sensor or a CMOS sensor and a lens
(these components are not shown) is attached to a central portion
11' of the front portion 11 by an appropriate attachment member
(not shown). Signals from the imaging device 17 are transmitted
through the wiring line (not shown) extending from the imaging
device 17 to the control device (control circuit) 18.
[0180] When the light shielding ratio of the virtual image
projection region of the light regulating device where the
projection image of the virtual image to the light regulating
device is included is defined as "1", at the time of operation of
the light regulating device 700, the light shielding ratio of the
other region 712 of the light regulating device 700 is, for
example, 0.95 or less. Alternatively, the light shielding ratio of
the other region of the light regulating device is, for example,
30% or less. On the other hand, at the time of operation of the
light regulating device 700, the light shielding ratio of the
virtual image projection region 711 of the light regulating device
700 is in a range of 35% to 99% and is, for example, 80%. In this
manner, the light shielding ratio of the virtual image projection
region 711 may be constant, and as described later, the light
shielding ratio may be changed depending on the illuminance of the
environment where the display apparatus is placed.
[0181] In the first embodiment, the later-described second to fifth
embodiments, or the later-described seventh to twelfth embodiments,
the light regulating device 700 which adjusts a light amount of
external light incident from the outside is disposed at the side of
the optical devices 120, 320, 520 opposite to the side where the
image forming devices 111, 211 is arranged and installed.
Specifically, the light regulating device 700 which is a kind of a
light shutter is fixed to the optical devices 120, 320, 520
(specifically, protection members (protective plates) 126, 326
protecting the light guide plates 121, 321 or a semi-transparent
mirror 520) by using an adhesive 708. Specifically, the outer edge
of a first substrate 701 of the light regulating device 700 and the
outer edge of the protection member 126 are adhered to each other
by the adhesive 708. The first substrate 701 of the light
regulating device 700 was configured to have the same shape as that
of the light guide plate 121. Namely, the size of the light
regulating device 700 was configured to be the same as the size of
the optical devices 120, 320, 520. However, the present disclosure
is not limited thereto, but the size may be large or may be small.
In short, the virtual image forming region (second deflecting units
140, 340 or the like) may be positioned within the projection image
of the light regulating device 700. This is the same in the
embodiments described hereinafter. The light regulating device 700
is disposed in the region of the optical devices 120, 320, 520 of
the side opposite to the observer 20. Namely, although the optical
device 120 and the light regulating device 700 are disposed in this
order from the observer side, the light regulating device 700 and
the optical devices 120, 320 may be disposed in this order. A
connector (not shown) is attached to the light regulating device
700, and the light regulating device 700 is electrically connected
to the control circuit (specifically, control device 18) for
controlling the light shielding ratio of the light regulating
device 700 through the connector and the wiring line.
[0182] The protection members (protective plates) 126, 326 are
adhered to the second surfaces 123, 323 of the light guide plates
121, 321 by adhesive members 127, 327, and the first deflecting
units 130, 330 and the second deflecting units 140, 340 are covered
with the protection members (protective plates) 126, 326.
[0183] In some cases, as illustrated in FIG. 6, the protection
member 126 may be omitted and the first substrate 701 of the light
regulating device 700 may also be configured to function as the
protection member 126. Therefore, the total weight of the display
apparatus can be reduced, and there is no problem in that the user
of the display apparatus feels discomfort. In addition, a second
substrate 703 may be configured to be thinner than the first
substrate 701. This is the same in the embodiments described
later.
[0184] In the first embodiment or the later-described second to
twelfth embodiments, as a schematic cross-sectional view is
illustrated in FIG. 4A and a schematic plan view is illustrated in
FIG. 4B, the light regulating device 700 is configured to include;
[0185] a first substrate 701, [0186] a second substrate 703 facing
the first substrate 701, [0187] a first transparent electrode 702
installed on a facing surface of the first substrate 701 facing the
second substrate 703, [0188] a second transparent electrode 704
installed on a facing surface of the second substrate 703 facing
the first substrate 701, and [0189] a light regulating layer 705
interposed between the first transparent electrode 702 and the
second transparent electrode 704. In addition, [0190] the first
transparent electrode 702 is configured with a plurality of
strip-shaped first transparent electrode segments 702A extending in
a first direction, [0191] the second transparent electrode 704 is
configured with a plurality of strip-shaped second transparent
electrode segments 704A extending in a second direction different
from the first direction, and [0192] control of the light shielding
ratio of a portion of the light regulating device corresponding to
an overlap region (light-shielding-ratio-varying minimum unit
region 709 of the light regulating device) between the first
transparent electrode segments 702A and the second transparent
electrode segments 704A is performed based on control of voltages
applied to the first transparent electrode segments 702A and the
second transparent electrode segments 704A. Namely, the control of
the light shielding ratio can be performed based on a simple matrix
scheme. The first direction and the second direction are
perpendicular to each other. Specifically, the first direction
extends in the lateral direction (X-axis direction), and the second
direction extends in the longitudinal direction (Y-axis
direction).
[0193] The first substrate 701 and the second substrate 703 are
configured with a plastic material. In addition, the first
transparent electrode 702 and the second transparent electrode 704
are configured with transparent electrodes made of an indium-tin
complex oxide (ITO) and are formed based on a combination of a PVD
method such as a sputtering method and a lift-off method. A
protective layer 706 configured with an SiN layer, an SiO.sub.2
layer, an Al.sub.2O.sub.3 layer, a TiO.sub.2 layer, or a stacked
layer thereof is formed between the second transparent electrode
704 and the second substrate 703. By forming the protective layer
706, an ion barrier property of preventing ions from incoming and
outgoing, a water proof property, a moisture-proof property, and
scratch resistance can be provided to the light regulating device
700. In addition, the first substrate 701 and the second substrate
703 are sealed at the outer edges by a sealing member 707
configured with a UV curable epoxy resin, a UV curable resin such
as an epoxy resin cured by UV light and heat, or a thermosetting
resin. The first transparent electrode 702 and the second
transparent electrode 704 are connected through a connector and a
wiring line (not shown) to the control device 18.
[0194] The light shielding ratio (light transmittance) of the light
regulating device 700 can be controlled by voltages applied to the
first transparent electrode 702 and the second transparent
electrode 704. Specifically, for example, if a voltage is applied
to the second transparent electrode 704 in the state that the first
transparent electrode 702 is grounded, the light shielding ratio of
the light regulating layer 705 is changed. A potential difference
between the first transparent electrode 702 and the second
transparent electrode 704 may be controlled, or the voltage applied
to the first transparent electrode 702 and the voltage applied to
the second transparent electrode 704 may be independently
controlled.
[0195] Furthermore, when the number of pixels in the virtual image
forming region (second deflecting units 140, 340) of the light
regulating device 700 is denoted by M.sub.0 and the number of
pixels in the longitudinal direction is denoted by N.sub.0, the
number M.sub.1.times.N.sub.1 of light-shielding-ratio-varying
minimum unit region 709 of the light regulating device 700 is, for
example, M.sub.0=M.sub.1 and N.sub.0=N.sub.1. However, the present
disclosure is not limited thereto, but in some embodiment, when
M.sub.1/M.sub.0=k and N.sub.1/N.sub.0=k' (herein, k and k' are
positive integers), 1.1.ltoreq.k, preferably,
1.1.ltoreq.k.ltoreq.1.5, more preferably, 1.15.ltoreq.k.ltoreq.1.3
and 1.1.ltoreq.k', preferably, 1.1.ltoreq.k'.ltoreq.1.5, more
preferably, 1.15.ltoreq.k'.ltoreq.1.3 may be satisfied. The value
of k and the value of k' may be equal to each other or may be
different from each other. In the embodiment, the values were set
so that k=k'=1.
[0196] In the first embodiment or the later-described second to
ninth embodiment, the light regulating device 700 is configured
with a light shutter using color change of a substance generated by
an oxidation/reduction reaction of an electrochromic material.
Specifically, the light regulating layer contains the
electrochromic material. More specifically, the light regulating
layer has a stacked structure of WO.sub.3 layer
705A/Ta.sub.2O.sub.5 layer 705B/Ir.sub.XSn.sub.1-XO layer 705C from
the second transparent electrode side. The WO.sub.3 layer 705A is
reduced to impart color. In addition, the Ta.sub.2O.sub.5 layer
705B constitutes a solid electrolyte, and the Ir.sub.XSn.sub.1-XO
layer 705C is oxidized to impart color.
[0197] In the Ir.sub.XSn.sub.1-XO layer, Ir and H.sub.2O react with
each other to exist as hydroxide iridium Ir(OH).sub.n. If a
negative potential is applied to the second transparent electrode
704 and a positive potential is applied to the first transparent
electrode 702, protons H.sup.+ move from the Ir.sub.XSn.sub.1-XO
layer to the Ta.sub.2O.sub.5 layer, and electrons are emitted to
the first transparent electrode 702. The following oxidation
reaction is performed, so that the Ir.sub.XSn.sub.1-XO layer is
colored.
Ir(OH).sub.n.fwdarw.IrO.sub.X(OH).sub.n-X(colored)+X.H.sup.++X.e.sup.-
[0198] On the other hand, protons H.sup.+ in the Ta.sub.2O.sub.5
layer move into the WO.sub.3 layer, and electrons from the second
transparent electrode 704 are injected into the WO.sub.3 layer. In
the WO.sub.3 layer, the following reduction reaction is performed,
so that the WO.sub.3 layer is colored.
WO.sub.3+X.H.sup.++X.e.fwdarw.H.sub.XWO.sub.3 (colored)
[0199] On the contrary, if a positive potential is applied to the
second transparent electrode 704 and a negative potential is
applied to the first transparent electrode 702, in the
Ir.sub.XSn.sub.1-XO layer, a reduction reaction proceeds in the
direction reverse to the above case and decoloring occurs; and in
the WO.sub.3 layer, an oxidation reaction proceeds in the direction
reverse to the above case and decoloring occurs. Furthermore, the
Ta.sub.2O.sub.5 layer includes H.sub.2O, and by applying a voltage
to the first transparent electrode and the second transparent
electrode, ionization occurs so that the state of protons H.sup.+
and OH ions is included to contribute to the coloring reaction and
the decoloring reaction.
[0200] In the first embodiment or the later-described second to
twelfth embodiments, for example, it is assumed that the observer
viewed the outside world as illustrated in FIG. 7 through the light
regulating device 700 in a low light shielding ratio state and the
optical devices 120, 320, 520. In addition, it is assumed that the
observer desired to acquire information on, for example, "how to
get to the station".
[0201] In this case, information or data on the images which are to
be displayed in the image display devices 100, 200, 300, 400, 500
or signals which are to be received by a reception device may be
recorded, stored, and preserved, for example, in a so-called
clouding computer or a server; by allowing the display apparatus to
include a communication unit (transmission/reception unit), for
example, a mobile phone or a smart phone or by incorporating a
communication unit (reception device) to the control device
(control circuit, control unit) 18, various types of information,
data, signals may be transmitted/received and exchanged between the
clouding computer or server and the display apparatus through the
communication unit; signals based on the various types of
information or data, namely, signals for displaying the image in
the image display devices 100, 200, 300, 400, 500 may be received;
and the reception device may receive the signals.
[0202] Specifically, if the observer performs an input of a message
requesting "information on station" as to-be-acquired information
to the mobile phone or the smart phone, the mobile phone or the
smart phone accesses the clouding computer or the server and
acquires the "information on station" from the clouding computer or
the server. Therefore, the control device 18 receives signals for
displaying the image in the image display devices 100, 200, 300,
400, 500. The control device 18 performs well-known image processes
based on the signals and displays the "information on station" as
an image in the image forming devices 111, 211. The image of the
"information on station" is displayed as a virtual image at a
predetermined position controlled by the control device 18 in the
optical devices 120, 320, 520 based on the light emitted from the
image forming devices 111, 211. Namely, the virtual image is formed
in a portion of the virtual image forming region (second deflecting
units 140, 340). In addition, the light regulating device 700 is
controlled so that the light shielding ratio of the virtual image
projection region 711 of the light regulating device 700 where the
projection image of the virtual image to the light regulating
device 700 is included is higher than the light shielding ratio of
the other region 712 of the light regulating device 700 (refer to
FIG. 8B). Specifically, voltages applied to the first transparent
electrode 702 and the second transparent electrode 704 are
controlled by the control device 18. Herein, the size and position
of the virtual image projection region 711 of the light regulating
device 700 are determined based on the signals for displaying the
image in the image forming devices 111, 211.
[0203] In some cases, in the image display devices 100, 200, 300,
400, 500, the signals for displaying the image may be stored in the
display apparatus (specifically, the control device 18, more
specifically, the image information storage device 18A).
[0204] Alternatively, the image imaged by the imaging device 17
installed in the display apparatus may be transmitted through the
communication unit to the clouding computer or the server, the
various types of information or data corresponding to the image
imaged by the imaging device 17 may be searched for in the clouding
computer or the server, the searched various types of information
or data may be transmitted through the communication unit to the
display apparatus, and the image of the searched various types of
information or data may be displayed in the image display devices
100, 200, 300, 400, 500. In addition, if this embodiment and the
input of the "information on station" are used together, since
information on the location where the observer exists, which
direction the observer is directed to, or the like can be added,
the "information on station" can be displayed in the image forming
devices 111, 211 at a higher accuracy.
[0205] An embodiment where, before the virtual image is formed in
the optical devices 120, 320, 520 based on the light emitted from
the image forming devices 111, 211 (refer to FIG. 8B), the light
shielding ratio of the virtual image projection region 711 of the
light regulating device 700 is increased (refer to FIG. 8A) may be
employed. As a time after the light shielding ratio of the virtual
image projection region 711 of the light regulating device 700 is
increased until the virtual image is formed, 0.5 seconds to 30
seconds may be exemplified. However, the present disclosure is not
limited thereto. In some embodiment, the light shielding ratio of
the virtual image projection region 711 of the light regulating
device 700 may be configured to be sequentially increased as time
elapses.
[0206] A case where one virtual image is formed in the optical
devices 120, 320, 520 based on the light emitted from the image
forming devices 111, 211 and, after that, the next virtual image
different from the one virtual image is formed is considered. in
some embodiment, in this case, when an area of the virtual image
projection region 711 of the light regulating device 700
corresponding to the one virtual image is denoted by S.sub.1 and an
area of the virtual image projection region 711 of the light
regulating device 700 corresponding to the next virtual image is
denoted by S.sub.2, [0207] in a case where S.sub.2/S.sub.1<0.8
or 1<S.sub.2/S.sub.1, the virtual image projection region 711 of
the light regulating device 700 where the next virtual image is
formed may be a region of the light regulating device 700 where the
projection image of the next virtual image to the light regulating
device 700 is formed (refer to FIGS. 9A to 9C), and [0208] in a
case where 0.8.ltoreq.S.sub.2/S.sub.1.ltoreq.1, the virtual image
projection region 711 of the light regulating device 700 where the
next virtual image is formed may be a region of the light
regulating device 700 where the projection image of the one virtual
image to the light regulating device 700 is formed. Namely, in some
embodiment, in the formation of the next virtual image from the
formation of the one virtual image, in a case where the area of the
virtual image projection region is decreased by 0% to 20%, the
virtual image projection region corresponding to the one virtual
image may be retained (namely, the state illustrated in FIG. 9A is
maintained).
[0209] In addition, as illustrated in FIG. 10, when virtual
rectangles 140A, 340A circumscribing the virtual image formed in
the optical devices 120, 320, 520 is considered, the virtual image
projection region 711 of the light regulating device 700 may be
configured to be larger than the virtual rectangles 140A, 340A. In
addition, in this case, when lateral and longitudinal lengths of
the virtual rectangles 140A, 340A circumscribing the virtual image
formed in the optical devices 120, 320, 520 are denoted by
L.sub.1-T and L.sub.1-L, respectively, and when the shape of the
virtual image projection region 711 of the light regulating device
700 is defined as a shape of a rectangle having lateral and
longitudinal lengths of L.sub.2-T and L.sub.2-L, the following
relationships are preferably satisfied;
1.0.ltoreq.L.sub.2-T/L.sub.1-T.ltoreq.1.5
1.0.ltoreq.L.sub.2-L/L.sub.1-L.ltoreq.1.5
[0210] FIG. 10 illustrates a state where "ABCD" is formed as a
virtual image.
[0211] The light regulating device 700 may be in an operation state
all the time. Alternatively, the operation/non-operation (on/off)
state may be defined according to instruction (manipulation) of the
observer. Alternatively, the light regulating device may be in a
non-operation state at a normal time and start operation based on
the signals for displaying the image in the image display devices
100, 200, 300, 400, 500. In order to define the
operation/non-operation state according to the instruction
(manipulation) of the observer, for example, the display apparatus
may further include a microphone, and the control of operation of
the light regulating device 700 may be performed by audio input
through the microphone. Specifically, switching of
operation/non-operation of the light regulating device 700 may be
controlled according to the instruction based on the voice of the
observer. Alternatively, the to-be-acquired information may be
input by the audio input. Alternatively, the display apparatus may
further include an IR incidence/emitting device, and the control of
operation of the light regulating device 700 may be performed by
the IR incidence/emitting device. Specifically, by detecting blink
of the observer by using the IR incidence/emitting device, the
switching of operation/non-operation of the light regulating device
700 may be controlled.
[0212] As described above, in the display apparatus according to
the first embodiment, when the virtual image is formed in a portion
of the virtual image forming region based on the light emitted from
the image forming device, since the light regulating device is
controlled so that the light shielding ratio of the virtual image
projection region of the light regulating device where the
projection image of the virtual image to the light regulating
device is included is higher than the light shielding ratio of the
other region of the light regulating device, high contrast can be
provided to the virtual image observed by the observer, and since
the high light shielding ratio region does not occupy the entire
light regulating device and only the narrow region, that is, the
virtual image projection region of the light regulating device
where the projection image of the virtual image to the light
regulating device is included becomes the high light shielding
ratio region, the observer using the display apparatus can securely
and safely recognize the external environment.
Second Embodiment
[0213] A second embodiment is a modification of the first
embodiment. As a conceptual view of an image display device 200 in
a display apparatus (head mounted display) according to the second
embodiment is illustrated in FIG. 11, in the second embodiment, an
optical device is a first-A-structure optical device, and the image
forming device 211 is a second-configuration image forming device.
Namely, the image forming device includes a light source 251 and a
scanning unit 253 which scans parallel light emitted from the light
source 251. More specifically, the image forming device 211 is
configured to include the light source 251, a collimator optical
system 252 which converts light emitted from the light source 251
into the parallel light, the scanning unit 253 which scans the
parallel light emitted from the collimator optical system 252, and
a relay optical system 254 which relays and emits the parallel
light scanned by the scanning unit 253. Furthermore, the entire
image forming device 211 may be accommodated in a housing 213 (in
FIG. 11, indicated by a dashed-dotted line). An opening (not shown)
is provided to the associated housing 213, and light is emitted
through the opening from the relay optical system 254. In addition,
each housing 213 is detachably attached to the temple 13 by the
installation member 19.
[0214] The light source 251 is configured with a light emitting
element which emits white light. In addition, the light emitted
from the light source 251 is incident on the collimator optical
system 252 having a totally positive optical power and is emitted
as parallel light. In addition, the parallel light is reflected by
a total reflection mirror 256, and by allowing a micro mirror to
rotatably move in two-dimensional directions, the incident parallel
light is horizontally scanned and vertically scanned by the
scanning unit 253 configured with an MEMS which can scan
two-dimensionally to form a kind of two-dimensional image, so that
virtual pixels (the number of pixels are set to be the same as that
of, for example, the first embodiment) are formed. In addition, the
light from the virtual pixels passes through the relay optical
system (parallel light emitting optical system) 254 configured with
a well-known relay optical system, so that a light flux formed as
parallel light is incident on the optical device 120.
[0215] Since the optical device 120 where the light flux formed as
parallel light in the relay optical system 254 is incident, guided,
and emitted has the same configuration and structure as those of
the optical device of the first embodiment, the detailed
description thereof is not provided. In addition, as described
above, since the display apparatus according to the second
embodiment also has substantially the same configuration and
structure as the display apparatus according to the first
embodiment except that the image forming device 211 is different,
the detailed description is not provided.
Third Embodiment
[0216] A third embodiment is also a modification of the first
embodiment. A conceptual view of an image display device 300 in a
display apparatus (head mounted display) according to the third
embodiment is illustrated in FIG. 12. In addition, an enlarged
schematic cross-sectional view of a portion of a reflective volume
hologram diffraction grating is illustrated in FIG. 13. In the
third embodiment, similarly to the first embodiment, the image
forming device 111 is a first-configuration image forming device.
In addition, an optical device 320 has the same basic configuration
and structure as those of the optical device 120 of the first
embodiment except that the configurations and structures of a first
deflecting unit and a second deflecting unit are different from
those of the first embodiment, and the optical device 320 is an
optical device having a first-B structure.
[0217] In the third embodiment, the first deflecting unit and the
second deflecting unit are arranged and installed on a surface
(specifically, the second surface 323 of the light guide plate 321)
of the light guide plate 321. In addition, the first deflecting
unit diffracts and reflects the light incident on the light guide
plate 321, and the second deflecting unit diffracts and reflects
the light propagating the inner portion of the light guide plate
321 by total reflection several times. Herein, the first deflecting
unit and the second deflecting unit are configured with diffraction
grating elements, specifically, reflective diffraction grating
elements, more specifically, reflective volume hologram diffraction
gratings. In the description hereinafter, the first deflecting unit
configured with a reflective volume hologram diffraction grating
is, for the convenience, referred to as a "first diffraction
grating member 330", and the second deflecting unit configured with
a reflective volume hologram diffraction grating is, for the
convenience, referred to as a "second diffraction grating member
340".
[0218] In addition, in the third embodiment or the later-described
fourth embodiment, the first diffraction grating member 330 and the
second diffraction grating member 340 are configured by stacking
single-layered diffraction grating layer. Furthermore, interference
fringe corresponding to one type of wavelength band (or wavelength)
is formed on each diffraction grating layer made of a photopolymer
material, and the manufacturing method in the related art is used.
The pitch of interference fringe formed in the diffraction grating
layer (diffraction optical element) is constant, and the
interference fringe has a shape of a straight line and is parallel
to the Y axis. Furthermore, the axial line of the first diffraction
grating member 330 and the axial line of the second diffraction
grating member 340 are parallel to the X axis, and the normal line
is parallel to the Z axis.
[0219] An enlarged schematic partial cross-sectional view of the
reflective volume hologram diffraction grating is illustrated in
FIG. 13. Interference fringe having an inclination angle (a slant
angle) .phi. is formed in the reflective volume hologram
diffraction grating. Herein, the inclination angle .phi. denotes an
angle between the surface of the reflective volume hologram
diffraction grating and the interference fringe. The interference
fringe is formed over a range from the inner portion to the surface
of the reflective volume hologram diffraction grating. The
interference fringe satisfies Bragg's condition. Herein, the
Bragg's condition denotes the condition that the following equation
(A) is satisfied. In the equation (A), m is a positive integer,
.lamda. is a wavelength, d is a pitch of a grating plane (an
interval of a virtual plane including the interference fringe in a
normal direction), and .theta. denotes a complementary angle of the
angle of incidence to the interference fringe. In addition, in a
case where light penetrates the diffraction grating member at an
incident angle .psi., the relationship among .theta., the
inclination angle .phi., and the incident angle .psi. is expressed
by the equation (B).
m.lamda.=2dsin(.theta.) (A)
.theta.=90 degrees-(.phi.+.psi.) (B)
[0220] As described above, the first diffraction grating member 330
is arranged and installed (adhered) to the second surface 323 of
the light guide plate 321 and diffracts and reflects the parallel
light incident on the light guide plate 321 so that the parallel
light incident from the first surface 322 on the light guide plate
321 is totally reflected through the inner portion of the light
guide plate 321. Moreover, as described above, the second
diffraction grating member 340 is arranged and installed (adhered)
to the second surface 323 of the light guide plate 321 and
diffracts and reflects the parallel light propagating the inner
portion of the light guide plate 321 by total reflection several
times to be emitted from the first surface 322 in the state that
the parallel light from the light guide plate 321 is
maintained.
[0221] In addition, in the light guide plate 321, the parallel
light propagates an inner portion thereof by total reflection and,
after that, is emitted. At this time, since the light guide plate
321 is thin and the optical path where the light passes through the
inner portion of the light guide plate 321 is long, the number of
times of total reflection until the light reaches the second
diffraction grating member 340 is different according to each angle
of view. More specifically, among the parallel light beams incident
on the light guide plate 321, the number of time of reflection of
the parallel light incident with an angle in the direction being
close to the second diffraction grating member 340 is smaller than
the number of times of reflection of the parallel light incident on
the light guide plate 321 with an angle in the direction being far
away from the second diffraction grating member 340. This is
because the parallel light which is diffracted and reflected in the
first diffraction grating member 330 and is incident on the light
guide plate 321 at an angle of the direction approaching the second
diffraction grating member 340 is smaller than the parallel light
which is incident on the light guide plate 321 at an angle of the
direction opposite thereto in terms of the angle between the light
propagating the inner portion of the light guide plate 321 and the
normal line of the light guide plate 321 when the light collides
with the inner surface of the light guide plate 321. In addition,
the shape of the interference fringe formed in the inner portion of
the second diffraction grating member 340 and the shape of the
interference fringe formed in the inner portion of the first
diffraction grating member 330 has a symmetry relationship with
respect to the virtual plane perpendicular to the axial line of the
light guide plate 321. The surfaces of the first diffraction
grating member 330 and the second diffraction grating member 340
which do not face the light guide plate 321 is covered with the
protection member (protective plate) 326, so that damage to the
first diffraction grating member 330 and the second diffraction
grating member 340 is prevented from occurring. Furthermore, the
light guide plate 321 and the protection member 326 are adhered to
each other in the outer periphery by the adhesive member 327. In
addition, a transparent protection film may be adhered to the first
surface 322 to protect the light guide plate 321.
[0222] Basically, the light guide plate 321 in the later-described
fourth embodiment also has the same configuration and structure as
those of the light guide plate 321 described above.
[0223] As described above, since the display apparatus according to
the third embodiment has substantially the same configuration and
structure as the display apparatus according to the first
embodiment except that the optical device 320 is different, the
detailed description is not provided.
Fourth Embodiment
[0224] A fourth embodiment is a modification of the third
embodiment. A conceptual view of an image display device in a
display apparatus (head mounted display) according to the fourth
embodiment is illustrated in FIG. 14. In the image display device
400 according to the fourth embodiment, the light source 251, the
collimator optical system 252, the scanning unit 253, the parallel
light emitting optical system (relay optical system 254), and the
like have the same configurations and structures
(second-configuration image forming device) as those of the second
embodiment. In addition, the optical device 320 in the fourth
embodiment has the same configuration and structure (optical device
having a first-B structure) as the optical device 320 in the third
embodiment. Since the display apparatus according to the fourth
embodiment has substantially the same configuration and structure
as the display apparatus according to the second embodiment except
for the above-described differences, the detailed description is
not provided.
Fifth Embodiment
[0225] A fifth embodiment is also a modification of the image
display device according to the first to fourth embodiments. A
schematic view as a display apparatus according to the fifth
embodiment is viewed from the front side is illustrated in FIG. 15,
and a schematic view viewed from the upper side is illustrated in
FIG. 16.
[0226] In the fifth embodiment, the optical device 520 constituting
the image display device 500 is configured with a semi-transparent
mirror where the light emitted from the image forming devices 111A
and 111B is incident and is emitted toward the pupil 21 of the
observer 20. Furthermore, in the fifth embodiment, the light
emitted from the image forming devices 111A and 111B propagates the
inner portion of a transparent member 521 such as a glass plate or
a plastic plate to be incident on the optical device 520
(semi-transparent minor). However, the light may also propagate the
air to be incident on the optical device 520. In addition, the
image forming device may also be configured as the image forming
device 211 described in the second embodiment.
[0227] Each of the image forming devices 111A and 111B is attached
to the front portion 11 by using, for example, a screw. In
addition, the member 521 is attached to each of the image forming
devices 111A and 111B, the optical device 520(semi-transparent
mirror) is attached to the member 521, and the light regulating
device 700 is attached to the optical device 520 (semi-transparent
minor). Since the display apparatus according to the fifth
embodiment has substantially the same configuration and structure
as the display apparatus according to the first to fourth
embodiments except for the above-described differences, the
detailed description is not provided.
Sixth Embodiment
[0228] The sixth embodiment is also modification of the image
display device in the first to fourth embodiments and relates to a
second-structure optical device and a second-configuration image
forming device. A schematic view as the display apparatus according
to the sixth embodiment is viewed from the upper side is
illustrated in FIG. 17. Furthermore, in FIG. 17, the imaging device
17 is omitted in illustration.
[0229] In the sixth embodiment, the optical device 520 constituting
the image display device 500 is configured with semi-transparent
minors 530A and 530B where the light emitted from light sources
251A and 251B is incident and is emitted toward the pupils 21 of
the observer 20. Furthermore, in the sixth embodiment, the light
emitted from the light source 251 installed in the housing 213
propagates an inner portion of an optical fiber (not shown) to be
incident on the scanning unit 253 attached to, for example, the
portion 11' of the frame 10 in the vicinity of the nose pads, and
the light scanned by the scanning unit 253 is incident on the
semi-transparent minors 530A and 530B. Alternatively, the light
emitted from the light sources 251A and 251B installed in the
housing 213 propagates an inner portion of an optical fiber (not
shown) to be incident on the scanning unit 253 attached to, for
example, the upper sides of the portions of the frame 10
corresponding to the two eyes, and the light scanned by the
scanning unit 253 is incident on the semi-transparent minors 530A
and 530B. Alternatively, the light which is emitted from the light
sources 251A and 251B installed in the housing 213 and is incident
on the scanning unit 253 installed in the housing 213 to be scanned
by the scanning unit 253 is directly incident on the
semi-transparent mirrors 530A and 530B. In addition, the light
reflected by the semi-transparent minors 530A and 530B is incident
on the pupils of the observer. The image forming device may be
configured substantially as the image forming device 211 described
in the second embodiment. The display apparatus according to the
sixth embodiment has substantially the same configuration and
structure as those of the display apparatus according to the first
to fourth embodiments except for the difference described above,
and thus, the detailed description is not provided.
Seventh Embodiment
[0230] A seventh embodiment is a modification of the first
embodiment. A schematic view as the display apparatus according to
the seventh embodiment is viewed from the upper side is illustrated
in FIG. 18A. In addition, a schematic diagram of a circuit which
controls an illuminance sensor is illustrated in FIG. 18B.
[0231] The display apparatus according to the seventh embodiment is
configured to further include an illuminance sensor (environment
illuminance measurement sensor) 721 which measures the illuminance
of the environment where the display apparatus is placed to control
a light shielding ratio of the light regulating device 700 based on
a measurement result of the illuminance sensor (environment
illuminance measurement sensor) 721. The luminance of the image
formed by the image forming devices 111, 211 is controlled together
or independently based on the measurement result of the illuminance
sensor (environment illuminance measurement sensor) 721. The
environment illuminance measurement sensor 721 having well-known
configuration and structure may be arranged in, for example, the
outer end portion of the optical devices 120, 320 or the outer end
portion of the light regulating device 700. The environment
illuminance measurement sensor 721 is connected through a connector
and a wiring line (not shown) to the control device 18. The control
device 18 includes a circuit which controls the environment
illuminance measurement sensor 721. The circuit which controls the
environment illuminance measurement sensor 721 may be configured to
include an illuminance calculation circuit which receives a
measurement value from the environment illuminance measurement
sensor 721 to obtain the illuminance, a comparison calculation
circuit which compares the value of the illuminance obtained by the
illuminance calculation circuit with a standard value, and an
environment illuminance measurement sensor control circuit which
controls the light regulating device 700 and/or the image forming
devices 111, 211 based on the value obtained by the comparison
calculation circuit. However, the circuit may be configured with a
well-known circuit. With respect to the control of the light
regulating device 700, the control of the light shielding ratio of
the light regulating device 700 is performed; and with respect to
the control of the image forming devices 111, 211, the control of
the luminance of the image formed by the image forming devices 111,
211 is performed. Furthermore, the control of the light shielding
ratio of the light regulating device 700 and the control of the
luminance of the image in the image forming devices 111, 211 may be
independently performed or may be performed in correspondence with
each other.
[0232] For example, when the measurement result of the illuminance
sensor (environment illuminance measurement sensor) 721 is a
predetermined value (first illuminance measurement value) or more,
the light shielding ratio of the light regulating device 700 is set
as a predetermined value (first light shielding ratio) or more. On
the other hand, when the measurement result of the illuminance
sensor (environment illuminance measurement 3 sensor) 721 is a
predetermined value (second illuminance measurement value) or less,
the light shielding ratio of the light regulating device 700 is set
as a pre-determined value (second light shielding ratio) or less.
Herein, as a first illuminance measurement value, 10 lux may be
exemplified; as a first light shielding ratio, any value of 99% to
70% may be exemplified; as a second illuminance measurement value,
0.01 lux may be exemplified; and as a second light shielding ratio,
any value of 49% to 1% may be exemplified.
[0233] Furthermore, the illuminance sensor (environment illuminance
measurement sensor) 721 in the seventh embodiment may be applied to
the display apparatus described in the second to sixth embodiments.
In addition, in a case where display apparatus include the imaging
device 17, the illuminance sensor (environment illuminance
measurement sensor) 721 may be configured with a light receiving
element for exposure measurement which is installed in the imaging
device 17.
[0234] In the display apparatus according to the seventh embodiment
or the later-described eighth embodiment, the light shielding ratio
of the light regulating device is controlled based on a measurement
result of the illuminance sensor (environment illuminance
measurement sensor), the luminance of the image formed by the image
forming device is controlled based on a measurement result of the
illuminance sensor (environment illuminance measurement sensor),
the light shielding ratio of the light regulating device is
controlled based on a measurement result of the second illuminance
sensor (transmitting light illuminance measurement sensor), and the
luminance of the image formed by the image forming device is
controlled based on a measurement result of the second illuminance
sensor (transmitting light illuminance measurement sensor).
Therefore, it may be possible to provide high contrast to the
virtual image observed by the observer, and it may be possible to
optimize the observation state of the virtual image depending on
the illuminance of the surrounding environment where the display
apparatus is placed.
Eighth Embodiment
[0235] An eighth embodiment is also a modification of the first
embodiment. A schematic view as a display apparatus according to
the eighth embodiment is viewed from the upper side is illustrated
in FIG. 19A. In addition, a schematic diagram of a circuit which
controls a second illuminance sensor is illustrated in FIG.
19B.
[0236] The display apparatus according to the eighth embodiment
further includes a second illuminance sensor (transmitting light
illuminance measurement sensor) 722 which measures illuminance
based on the light passing from the external environment through
the light regulating device, namely, measures whether or not the
environment light passes through the light regulating device to be
adjusted to a desired illuminance to be incident, and the light
shielding ratio of the light regulating device 700 is controlled
based on the measurement result of the second illuminance sensor
(transmitting light illuminance measurement sensor) 722. in
addition, together or independently, the luminance of the image
formed by the image forming devices 111, 211 is controlled based on
the measurement result of the second illuminance sensor
(transmitting light illuminance measurement sensor) 722. The
transmitting light illuminance measurement sensor 722 having
well-known configuration and structure is disposed in a side closer
to the observer than the optical devices 120, 320, 520.
Specifically, the transmitting light illuminance measurement sensor
722 may be disposed, for example, on an inner surface of the
housings 113, 213 or a surface of the observer side of the light
guide plates 121, 321. The transmitting light illuminance
measurement sensor 722 is connected to a control device 18 through
a connector and a wiring line (not shown). The control device 18
includes a circuit which controls the transmitting light
illuminance measurement sensor 722. The circuit which controls the
transmitting light illuminance measurement sensor 722 may be
configured to include an illuminance calculation circuit which
receives a measurement value from the transmitting light
illuminance measurement sensor 722 to obtain the illuminance, a
comparison calculation circuit which compares the value of the
illuminance obtained by the illuminance calculation circuit with a
standard value, and a transmitting light illuminance measurement
sensor control circuit which controls the light regulating device
700 and/or the image forming devices 111, 211 based on the value
obtained by the comparison calculation circuit. However, the
circuit may be configured with a well-known circuit. With respect
to the control of the light regulating device 700, the control of
the light shielding ratio of the light regulating device 700 is
performed, and on the other hand, with respect to the control of
the image forming devices 111, 211, the control of the luminance of
the image formed by the image forming devices 111, 211 is
performed. Furthermore, the control of the light shielding ratio of
the light regulating device 700 and the control of the luminance of
the image in the image forming devices 111, 211 may be
independently performed or may be performed in correspondence with
each other. Moreover, in a case where the measurement result of the
transmitting light illuminance measurement sensor 722 is not
controlled from the illuminance of the environment illuminance
measurement sensor 721 to the desired illuminance, namely, in a
case where the measurement result of the transmitting light
illuminance measurement sensor 722 does not become the desired
illuminance, or in a case where further fine illuminance adjustment
is desired, the light shielding ratio of the light regulating
device may be regulated while monitoring the value of the
transmitting light illuminance measurement sensor 722. At least two
second illuminance sensors (transmitting light illuminance
measurement sensors) may be arranged, and the measurement of
illuminance based on the light passing through a high light
shielding ratio portion and the measurement of illuminance based on
the light passing through a low light shielding ratio portion may
be performed.
[0237] Furthermore, the second illuminance sensor (transmitting
light illuminance measurement sensor) 722 in the eighth embodiment
may be applied to the display apparatus described in the second to
sixth embodiments. Alternatively, the second illuminance sensor
(transmitting light illuminance measurement sensor) 722 in the
eighth embodiment and the illuminance sensor (environment
illuminance measurement sensor) 721 in the seventh embodiment may
be combined; and in this case, various tests are performed, and the
control of the light shielding ratio of the light regulating device
700 and the control of the luminance of the image in the image
forming devices 111, 211 may be independently performed or may be
performed in correspondence with each other. In the light
regulating device for the right eye and the light regulating device
for the left eye, respectively, by adjusting voltages applied to
the first transparent electrode and the second transparent
electrode, equalization between the light shielding ratio of the
light regulating device for the right eye and light shielding ratio
of the light regulating device for the left eye may be implemented.
The potential difference between the first transparent electrode
and the second transparent electrode may be controlled, and the
voltage applied to the first transparent electrode and the voltage
applied to the second transparent electrode may be independently
controlled. The light shielding ratio of the light regulating
device for the right eye and light shielding ratio of the light
regulating device for the left eye may be controlled, for example,
based on the measurement result of the second illuminance sensor
(transmitting light illuminance measurement sensor) 722.
Alternatively, by observing the brightness of the light passing
through the light regulating device and optical device for the
right eye and the brightness of the light passing through the light
regulating device and optical device for the left eye by the
observer, the observer may manually perform the control and
regulation by manipulating a switch, a button, a dial, a slider, a
knob, and the like.
Ninth Embodiment
[0238] A ninth embodiment is a modification of the first to eighth
embodiments. A conceptual view of an image display device is
illustrated in FIG. 20, a schematic view as the display apparatus
is viewed from the upper side is illustrated in FIG. 21, and a
schematic view as the display apparatus is viewed from the lateral
side is illustrated in FIG. 22. A light shielding member 731 may be
installed in the display apparatus according to the ninth
embodiment. Specifically, for example, the light shielding member
731 which blocks the incidence of the external light to the optical
device 120 is arranged in the region of the optical device 120
where the light emitted from the image forming devices 111A and
111B is incident, specifically, the region where the first
deflecting unit 130 is installed. Herein, the region of the optical
device 120 where the light emitted from the image forming devices
111A and 111B is incident is included within the projection image
of the light shielding member 731 to the optical device 120. In
addition, the projection image of the end portion of the light
regulating device 700 to the optical device 120 is included within
the projection image of the light shielding member 731 to the
optical device 120. The light shielding member 731 is disposed at
the side of the optical device 120 opposite to the side where the
image forming devices 111A and 111B is disposed so as to be
separated from the optical device 120. The light shielding member
731 is made of, for example, a non-transparent plastic material,
and the light shielding member 731 extends integrally from the
housing 113 of the image forming devices 111A and 111B.
Alternatively, the light shielding member is attached to the
housing 113 of the image forming devices 111A and 111B.
Alternatively, the light shielding member extends integrally from
the frame 10. Alternatively, the light shielding member is attached
to the frame 10. Furthermore, in the illustrated example, the light
shielding member 731 extends integrally from the housing 113 of the
image forming devices 111A and 111B. In this manner, since the
light shielding member blocking the incidence of external light to
the optical device is arranged in the region of the optical device
where the light emitted from the image forming device is incident,
even though the light amount of incidence of the external light is
changed due to the operation of the light regulating device, since
the external light is not incident on the region of the optical
device where the light emitted from the image forming device is
incident, specifically, on the first deflecting unit 130, there is
no problem in that the image display quality of the display
apparatus is deteriorated due to the occurrence of undesired stray
light or the like. Furthermore, in the illustrated example, the
size of the first substrate 701 of the light regulating device 700
is configured to be smaller than that of the light guide plate 121,
but the present disclosure is not limited thereto.
[0239] Alternatively, as illustrated in FIG. 23, a light shielding
member 732 is arranged in the portion of the optical device 120 of
the side opposite to the side where the image forming devices 111A
and 111B is arranged. Specifically, the light shielding member 732
may be formed by printing the optical device 120 (specifically, the
inner surface of the protection member 126) with a non-transparent
ink. Furthermore, the light shielding member 731 and the light
shielding member 732 may be combined. The light shielding member
732 may be formed on the outer surface of the protection member
126.
[0240] Alternatively, as a conceptual view is illustrated in FIG.
24 or FIG. 25, the light shielding member 733 is arranged in the
light regulating device 700. Specifically, the light shielding
member 733 may be formed by printing on the light regulating device
700 with a non-transparent ink. Furthermore, in the example
illustrated in FIG. 24, the light shielding member 733 is formed on
an outer surface of the first substrate 701 of the light regulating
device 700; and in the example illustrated in FIG. 25, the light
shielding member 733 is formed on an inner surface of the first
substrate 701 of the light regulating device 700. Furthermore, the
light shielding member 731 and the light shielding member 733 may
be combined, the light shielding member 732 and the light shielding
member 733 may be combined, and the light shielding member 731, the
light shielding member 732, and the light shielding member 733 may
be combined.
Tenth Embodiment
[0241] A tenth embodiment is a modification of the first to ninth
embodiments. In the tenth embodiment, a light regulating layer was
configured with an electrophoretic dispersion liquid. Hereinafter,
a method of manufacturing an electrophoretic dispersion liquid will
be described.
[0242] First, 10 grams of carbon black (#40 manufactured by
Mitsubishi Chemical Corporation) as electrophoretic particles was
added to 1 liter of pure water, and after stiffing, 1 cm.sup.3 of
37 mass % of hydrochloric acid and 0.2 grams of 4-vinyl aniline
were added, so that a solution-A was prepared. On the other hand,
0.3 grams of sodium nitrite was dissolved into 10 cm.sup.3 of pure
water, and after that, heating was performed up to 40 degree C., so
that a solution-B was prepared. In addition, the solution-B was
slowly added to the solution-A, and stirring was performed for 10
hours. After that, by centrifuging the product obtained by the
reaction, a solid was obtained. Next, the solid was washed with
pure water, and the solid was further washed in a method of
dispersing the solid in acetone and, after that, centrifuging.
After that, the solid was dried in a vacuum drier at a temperature
of 50 degree C. one night.
[0243] Next, in a reaction flask attached with a nitrogen purge
device, an electromagnetic stir bar, and a reflux column, 5 grams
of the solid, 100 cm.sup.3 of toluene, 15 cm.sup.3 of methacrylic
acid 2-ethylhexyl, and 0.2 grams of azobisisobutyronitrile (AIBN)
was inserted and mixed. In addition, while stiffing, the reaction
flask was purged with a nitrogen gas for 30 minutes. After that,
the reaction flask was put into an oil bath, and while continuously
stiffing, heating was slowly performed up to 80 degree C. This
state was maintained for 10 hours. After that, cooling was
performed down to the room temperature, and the solid was
centrifuged. After the solid was washed by performing three times
of the operation of centrifuging the solid together with
tetrahydrofuran (THF) and ethyl acetate, the solid was taken out
and dried in the vacuum drier at a temperature of 50 degree C. one
night. Therefore, 4.7 grams of brown electrophoretic particles was
obtained.
[0244] On the other hand, as a dispersion liquid (dispersion
medium) which is an insulating liquid, Isopar G (manufactured by
Exxon Mobil Corporation) solution containing 0.5% of
N,N-dimethyl-1,3-diamine, 1,2-hydroxy octadecanoic acid, and
methoxy sulfonyloxy methane (Solsperse 17000 manufactured by Nippon
Lubrizol Corporation) and 1.5% of Sorbitan Trioleate (SPAN 85) was
prepared. In addition, 0.1 grams of the electrophoretic particles
was added to 9.9 grams of the dispersion medium, and stirring was
performed for 5 minutes with a bead mill. After that, the mixture
solution was centrifuged for 5 minutes in a centrifuge (rotational
speed=2000 rpm), and after that, the beads are removed. Therefore,
the electrophoretic dispersion liquid was obtained. Furthermore,
the electrophoretic particles are positively charged.
[0245] In the light regulating device 700 in the tenth embodiment,
the interval between the first substrate 701 and the second
substrate 703 made of a glass having a thickness of 0.5 mm was set
to 50 .mu.m. The first transparent electrode 702 and the second
transparent electrode 704 are made of an indium-tin complex oxide
(ITO) and are formed based on a combination of a PVD method such as
a sputtering method and a lift-off method. The first transparent
electrode 702 is patterned in a shape of comb-like electrodes. On
the other hand, the second transparent electrode 704 is not
patterned and is a so-called solid electrode. The first transparent
electrode 702 and the second transparent electrode 704 are
connected to the control device 18 through connectors and wiring
lines (not shown).
[0246] The light shielding ratio (light transmittance) of the light
regulating device 700 can be controlled by voltages applied to the
first transparent electrode 702 and the second transparent
electrode 704. Specifically, if a relatively positive voltage is
applied to the first transparent electrode 702 and a relatively
negative voltage is applied to the second transparent electrode
704, the positively-charged electrophoretic particles migrate to
cover the second transparent electrode 704. Therefore, the light
shielding ratio of the light regulating device 700 has a high
value. On the other hand, on the contrary, if a relatively negative
voltage is applied to the first transparent electrode 702 and a
relatively positive voltage is applied to the second transparent
electrode 704, the electrophoretic particles migrate to cover the
first transparent electrode 702. Therefore, the light shielding
ratio of the light regulating device 700 has a low value. The
voltages applied to the first transparent electrode 702 and the
second transparent electrode 704 may be controlled by the observer
manipulating a control knob installed in the control device 18.
Namely, the observer observes the virtual image from the optical
device 120, 320 and regulates the light shielding ratio of the
light regulating device 700 so that the improvement of contrast of
the virtual image may be achieved.
Eleventh Embodiment
[0247] An eleventh embodiment is a modification of the tenth
embodiment. In the tenth embodiment, the color colored by the light
regulating device 700 was set to a fixed color of black. On the
other hand, in the eleventh embodiment, the light passing through
the light regulating device is colored in a desired color by the
light regulating device, and in addition, the color colored by the
light regulating device is variable. Specifically, the light
regulating device is configured by stacking a light regulating
device colored in red, a light regulating device colored in yellow,
and a light regulating device colored in blue. Herein, the
electrophoretic dispersion liquid in the light regulating device
colored in red is configured as a dispersion liquid by dispersing
particles obtained by preliminarily mixing a styrene-based resin
and C. I. Pigment Red 122 as electrophoretic particles by a
Henschel mixer, performing melting and kneading in a twin-screw
extruder, performing cooling, performing coarse pulverizing with a
hammer mill, and performing fine pulverizing with a jet mill in
Isopar G (manufactured by Exxon Mobil Corporation) solution
containing 0.5% of N,N-dimethyl-1,3-diamine, 1,2-hydroxy
octadecanoic acid and methoxy sulfonyloxy methane (Solsperse 17000
manufactured by Nippon Lubrizol Corporation) and 1.5% of Sorbitan
Trioleate (SPAN 85). In addition, the electrophoretic dispersion
liquid in the light regulating device colored in yellow is
configured as a dispersion liquid by dispersing particles obtained
by preliminarily mixing a styrene-based resin and C. I. Pigment
Yellow 12 as electrophoretic particles by a Henschel mixer,
performing melting and kneading in a twin-screw extruder,
performing cooling, performing coarse pulverizing with a hammer
mill, and performing fine pulverizing with a jet mill in Isopar G
(manufactured by Exxon Mobil Corporation) solution containing 0.5%
of N,N-dimethyl-1,3-diamine, 1,2-hydroxy octadecanoic acid and
methoxy sulfonyloxy methane (Solsperse 17000 manufactured by Nippon
Lubrizol Corporation) and 1.5% of Sorbitan Trioleate (SPAN 85).
Moreover, the electrophoretic dispersion liquid in the light
regulating device colored in blue is configured as a dispersion
liquid by dispersing particles obtained by preliminarily mixing a
styrene-based resin and C. I. Pigment Blue 1 as electrophoretic
particles by a Henschel mixer, performing melting and kneading in a
twin-screw extruder, performing cooling, performing coarse
pulverizing with a hammer mill, and performing fine pulverizing
with a jet mill in Isopar G (manufactured by Exxon Mobil
Corporation) solution containing 0.5% of N,N-dimethyl-1,3-diamine,
1,2-hydroxy octadecanoic acid and methoxy sulfonyloxy methane
(Solsperse 17000 manufactured by Nippon Lubrizol Corporation) and
1.5% of Sorbitan Trioleate (SPAN 85). In addition, by controlling
the applying of voltages to the electrode in the light regulating
devices, the external light emitted from a three-layered light
regulating device can be colored in a desired color.
[0248] Since the configuration and structure of the display
apparatus according to the eleventh embodiment are the same as the
configuration and structure of the display apparatus described in
the tenth embodiment except for the points described above, the
detailed description is not provided.
Twelfth Embodiment
[0249] A twelfth embodiment relates to an initial setting method
for the display apparatus according to an embodiment of the present
disclosure. As a display apparatus in the twelfth embodiment, the
display apparatuses described in the first to eleventh embodiments
are used. Namely, the initial setting method for the display
apparatus according to the twelfth embodiment is as follows. If the
initial setting method is described based on the display apparatus
described in the first to fifth embodiments, in the display
apparatus including: [0250] (A) a frame 10 (for example, a
glasses-type frame 10) which is mounted on the head of an observer
20, [0251] (B) image display devices 100, 200, 300, 400, 500 which
are attached to the frame 10, and [0252] (C) a light regulating
device 700 which regulates a light amount of external light
incident from the outside, [0253] the image display devices 100,
200, 300, 400, 500 is configured to include: [0254] (a) image
forming devices 111, 211, [0255] and [0256] (b) optical devices
120, 320, 520 having a virtual image forming region where a virtual
image is formed based on light emitted from the image forming
devices 111, 211, [0257] the virtual image forming region of the
optical devices 120, 320, 520 overlaps the light regulating device
700, [0258] when the virtual image is formed in a portion of the
virtual image forming region based on the light emitted from the
image forming devices 111, 211, the light regulating device 700 is
controlled so that the light shielding ratio of the virtual image
projection region 711 of the light regulating device 700 where the
projection image of the virtual image to the light regulating
device 700 is included is higher than the light shielding ratio of
the other region 712 of the light regulating device 700.
[0259] For example, in a case where the observer using the display
apparatus is replaced, a position of the virtual image projection
region 711 of the light regulating device 700 where the projection
image of the virtual image to the light regulating device 700 is
included is changed (refer to FIG. 26A). Therefore, the
initialization of the position of the virtual image projection
region 711 of the light regulating device 700 where the projection
image of the virtual image to the light regulating device 700 is
included can be securely performed based on the initial setting
method for the display apparatus according to the twelfth
embodiment.
[0260] Specifically, a virtual image of the test pattern (in FIG.
26A, indicated by hatching lines directed from the upper left to
the lower right) is displayed in the virtual image forming region
(second deflecting units 140, 340) of the optical devices 120, 320,
520 based on a test pattern emitted from the image forming devices
111, 211, and the light shielding ratio of a region 711A of the
light regulating device 700 corresponding to the virtual image of
the test pattern is set to be higher than the light shielding ratio
of the other region 712 of the light regulating device 700. Herein,
in FIG. 26A, the position of the virtual image formed in the
imaginary virtual image forming plane is denoted by "A", and the
position of the region 711A of the light regulating device 700 when
the region 711A of the light regulating device 700 is projected on
the imaginary virtual image forming plane is denoted by "B". In
addition, the virtual image of the test pattern and the high light
shielding ratio region of the light regulating device 700 are
allowed to be moved relative to each other so that the virtual
image of the test pattern observed by the observer and the high
light shielding ratio region 711A of the light regulating device
700 observed by the observer overlap each other. Namely, the
virtual image of the test pattern and the high light shielding
ratio region of the light regulating device 700 are allowed to be
moved relative to each other so that the position "A" of the
virtual image and the position "B" of the region 711A of the light
regulating device 700 overlap each other.
[0261] Although the test pattern basically has an arbitrary shape,
for example, as illustrated in FIG. 26B, characters (in the
illustrated example, characters "A" and "B") are displayed at the
center and four corners of the virtual image forming region (second
deflecting units 140, 340) of the optical devices 120, 320, 520.
The virtual image of the test pattern and the high light shielding
ratio region 711A of the light regulating device 700 are allowed to
be moved relative to each other. Specifically, the image signal of
the test pattern is processed so that the position of the virtual
image of the test pattern in the optical devices 120, 320, 520 is
moved in units of a pixel. Alternatively, a process of changing the
position of the minimum unit region 709 is performed so that the
light-shielding-ratio-varying minimum unit region 709 of the light
regulating device 700 is moved. Alternatively, the configurations
are combined. In order to move the virtual image of the test
pattern and high light shielding ratio region 711A of the light
regulating device 700 relative to each other, the observer may
manually perform the movement. Specifically, the observer may
manually perform by manipulating a switch, a button, a dial, a
slider, a knob, and the like. The relative movement may be movement
in the X-axis direction and the later-described movement in the
Y-axis direction, rotational movement, expansion, constriction, and
modification. Furthermore, in the example illustrated in FIG. 26B,
the expansion in the X-axis direction may be implemented.
[0262] Furthermore, the position relationship between the formation
position of the virtual image in the optical devices 120, 320, 520
and the position of the virtual image projection region of the
light regulating device 700 may be corrected by using as a
reference the movement amount when the virtual image of the test
pattern and the high light shielding ratio region 711A of the light
regulating device 700 are moved relative to each other.
Specifically, the position relationship between the formation
position of the virtual image in the optical devices 120, 320, 520
and the position of the virtual image projection region 711 of the
light regulating device 700 may be corrected based on the image
signal processing amount when the image signal of the test pattern
is processed so that the position of the virtual image of the test
pattern in the optical devices 120, 320, 520 is moved in units of a
pixel, based on the process of moving the high light shielding
ratio region 711A of the light regulating device 700 by using the
minimum unit region 709 as a unit of movement, or based on a
combination thereof.
[0263] Furthermore, at this time, the observer may also determine
the light shielding ratio of the other region 712 of the light
regulating device at the time of operation of the light regulating
device 700. In addition, the light shielding ratio of the virtual
image projection region 711 of the light regulating device at the
time of operation of the light regulating device 700 may also be
determined. In addition, in a case where the virtual rectangles
140A, 340A circumscribing the virtual image formed in the optical
devices 120, 320, 520 is considered, when lateral and longitudinal
lengths of the virtual rectangles 140A, 340A are denoted by
L.sub.1-T and L.sub.1-L, respectively, and when the shape of the
virtual image projection region 711 of the light regulating device
700 is defined as a shape of a rectangle having lateral and
longitudinal lengths of L.sub.2-T and L.sub.2-L, the observer may
also determine a value of L.sub.2-T/L.sub.1-T and the
L.sub.2-L/L.sub.1-L.
[0264] Heretofore, the present disclosure is described based on
exemplary embodiments, but the present disclosure is not limited to
the embodiments. The configuration and structures of the display
apparatuses (head mounted displays) and the image display devices
described in the embodiments are exemplary ones, and thus,
appropriate modifications are available. For example, a
surface-relief-type hologram (refer to US Patent 20040062505 A1)
may be disposed in the light guide plate. In the optical device
320, the diffraction grating element may be configured with a
transmissive diffraction grating element. Alternatively, in some
embodiment, any one of the first deflecting unit and the second
deflecting unit is configured with a reflective diffraction grating
element, and the other may be configured with a transmissive
diffraction grating element. Alternatively, the diffraction grating
element may also be configured as a reflective blazed diffraction
grating element. The display apparatus according to an embodiment
of the present disclosure may also be used as a stereoscopic
display apparatus. In this case, as necessary, a polarizing plate
or a polarizing film may be detachably attached to the optical
device, or a polarizing plate or a polarizing film may be adhered
to the optical device.
[0265] In the embodiments, although it is described that the image
forming devices 111, 211 display a monochrome (for example, green)
image, the image forming devices 111, 211 may display a color
image. In this case, light source may be configured with light
sources which emit, for example, red, green, and blue,
respectively. Specifically, for example, red light, green light,
and blue light emitted from a red light emitting element, a green
light emitting element, and a blue light emitting element,
respectively, may be mixed and luminance-equalized by using a light
pipe to white light.
[0266] In some embodiment, the frame may be configured to include a
front portion arranged in front of the observer, two temples
rotatably attached to two ends of the front portion through hinges,
and nose pads, and the light regulating device 700 may be arranged
and installed in the front portion. In addition, in some
embodiment, the optical device may be attached to the light
regulating device 700. Furthermore, the optical device may be
attached to the light regulating device 700 in a closely contacted
state or may be attached to the light regulating device 700 with a
gap. Moreover, in some embodiment, in this case, as described
above, the front portion may have a rim, and the light regulating
device 700 may be fitted to the rim. Alternatively, in some
embodiment, at least one of the first substrate 701 and the second
substrate 703 may be fitted to the rim. In some embodiment, the
light regulating device 700 and the light guide plates 121, 321 may
be fitted to the rim. In some embodiment, the light guide plates
121, 321 may be fitted to the rim.
[0267] The light regulating layer 705 may be configured with a
light shutter made of a liquid crystal display device. In this
case, specifically, the light regulating layer 705 may be
configured with, for example, a liquid crystal material layer made
of a TN (twisted nematic) type liquid crystal material or an STN
(super twisted nematic) type liquid crystal material. The first
transparent electrode 702 and the second transparent electrode 704
are patterned, and the light shielding ratio (light transmittance)
of the region 712 of a portion of the light regulating device 700
may be changed into a state different from the light shielding
ratio of the other region. Alternatively, one of the first
transparent electrode 702 and the second transparent electrode 704
is configured as a so-called solid electrode where patterning is
not performed, the other is patterned, and the other is connected
to a TFT. In addition, the control of the light shielding ratio of
the light-shielding-ratio-varying minimum unit region 709 of the
light regulating device 700 is performed by the TFT. Namely, the
control of the light shielding ratio may be performed based on an
active matrix. The control of the light shielding ratio based on an
active matrix may also be applied to the light regulating device
700 described in the first to twelfth embodiments.
[0268] In addition, a light shutter which controls the light
shielding ratio (light transmittance) by an electrowetting
phenomenon may also be used. Specifically, a first transparent
electrode and a second transparent electrode are installed, and the
space between the first transparent electrode and the second
transparent electrode is filled with an insulating first liquid and
a conductive second liquid. In addition, by applying a voltage
between the first transparent electrode and the second transparent
electrode, a shape of the interface formed by the first liquid and
the second liquid is changed, for example, from a planar shape to a
curved state, so that the light shielding ratio (light
transmittance) can be controlled. Alternatively, a light shutter
utilizing an electrode-position method (electrodeposition
electric-field precipitation) based on an
electrode-position/dissociation phenomenon which occurs by a
reversible oxidation/reduction reaction of a metal (for example,
silver particles) may also be used. Specifically, by dissolving
Ag.sup.+ and I in an organic solvent and by applying an appropriate
voltage to an electrode, Ag.sup.- is allowed to be reduced, and
thus, Ag is precipitated, so that the light shielding ratio (light
transmittance) of the light regulating device is decreased; and by
oxidizing Ag to be dissolved as Ag.sup.+, the light shielding ratio
(light transmittance) of the light regulating device is
increased.
[0269] In some cases, the light passing through the light
regulating device may be configured to be colored in a desired
color by the light regulating device, and in this case, the color
colored by the light regulating device may be configured to be
variable. Specifically, for example, a light regulating device
colored in red, a light regulating device colored in green, and a
light regulating device colored in blue may be stacked.
[0270] The light regulating device may be detachably arranged and
installed in the region of the optical device where the light is
emitted. In this manner, in order to detachably arrange and install
the light regulating device, for example, the light regulating
device may be attached to the optical deice by using a screw made
of a transparent plastic and may be connected through a connector
and a wiring line to the control circuit (for example, included in
the control device 18 for controlling the image forming device) for
controlling the light transmittance of the light regulating
device.
[0271] A schematic view as a modified example of the optical device
constituting the second-structure optical device described in the
sixth embodiment is viewed from the upper side is illustrated in
FIGS. 27A and 27B. Furthermore, in FIGS. 27A, 27B, and 28A, the
light regulating device is omitted in illustration.
[0272] In the example illustrated in FIG. 27A, the light from a
light source 601 infiltrates into a light guiding member 602 to
collide with a polarizing beam splitter 603 installed in the light
guiding member 602. Among the light beams from the light source 601
which collides with the polarizing beam splitter 603, the P
polarization components pass through the polarizing beam splitter
603, and the S polarization components are reflected by the
polarizing beam splitter 603 to be directed to a liquid crystal
display device (LCD) 604 configured with a LCOS as a light valve.
The image is formed by the liquid crystal display device (LCD) 604.
Since the polarization components of the light reflected by the
liquid crystal display device (LCD) 604 occupy the P polarization
components, the light reflected by the liquid crystal display
device (LCD) 604 passes through polarizing beam splitters 603 and
605, passes through a 1/4-wave plate 606, collides with a
reflecting plate 607 to be reflected, and passes through the
1/4-wave plate 606 to be directed to the polarizing beam splitter
605. At this time, since the polarization components of the light
occupy the S polarization components, the light is reflected by the
polarizing beam splitter 605 to be directed to the pupil 21 of the
observer. As described above, the image forming device is
configured to include the light source 601 and the liquid crystal
display device (LCD) 604, the optical device is configured to
include the light guiding member 602, the polarizing beam splitters
603 and 605, the 1/4-wave plate 606, and the reflecting plate 607,
and the polarizing beam splitter 605 corresponds to the virtual
image forming region of the optical device.
[0273] In the example illustrated in FIG. 27B, the light from an
image forming device 611 propagates a light guiding member 612 to
collide with a semi-transparent mirror 613, a portion of the light
transmits the semi-transparent minor 613 and collides with a
reflecting plate 614 to be reflected and to collide with the
semi-transparent mirror 613 again, and a portion of the light is
reflected by the semi-transparent minor 613 to be directed to the
pupil 21 of the observer. As described, the optical device is
configured to include the light guiding member 612, the
semi-transparent mirror 613, and the reflecting plate 614, and the
semi-transparent mirror 613 corresponds to the virtual image
forming region of the optical device.
[0274] Alternatively, a schematic view as an optical device in
another modification example of the display apparatus according to
the sixth embodiment is viewed from the upper side and a schematic
view as the optical device is viewed from the lateral side are
illustrated in FIGS. 28A and 28B. The optical device is configured
to include a hexahedral prism 622 and a convex lens 625. The light
emitted from an image forming device 621 is incident on the prism
622, collides with a prism surface 623 to be reflected, propagates
the prism 622, collides with a prism surface 624 to be reflected,
and reaches the pupil 21 of the observer through the convex lens
625. The prism surface 623 and the prism surface 624 are tilted in
the directions to face each other, and the plane shape of the prism
622 is a shape of a trapezoid, specifically, an isosceles
trapezoid. Mirror coating is performed on the prism surfaces 623
and 624. If the thickness (height) of the portion of the prism 622
facing the pupil 21 is set to be smaller than an average pupil
diameter of human beings, that is, 4 mm, the observer can view the
image of the outside world and the virtual image from the prism 622
in an overlapped manner.
[0275] In some embodiment, in some cases, as a conceptual view of
an image display device in a modification example of the display
apparatus according to the third and fourth embodiments is
illustrated in FIG. 29, the first deflecting unit 330 may be
configured to include a first hologram diffraction grating 331 and
a second hologram diffraction grating 332, the second deflecting
unit 340 may be configured to include a third hologram diffraction
grating 341, [0276] a first interference fringe may be formed in an
inner portion of the first hologram diffraction grating 331, [0277]
a second interference fringe may be formed in an inner portion of
the second hologram diffraction grating 332, and [0278] a third
interference fringe may be formed in an inner portion of the third
hologram diffraction grating 341; and the following relationships
may be satisfied:
[0278] .phi..sub.1<.phi..sub.3<.phi..sub.2 and
P.sub.1=P.sub.3=P.sub.2 [0279] Furthermore, the hologram
diffraction gratings 331, 332, and 341 are configured with
reflective volume hologram diffraction gratings. Herein, [0280]
.phi..sub.1: a slant angle of the first interference fringe [0281]
.phi..sub.2: a slant angle of the second interference fringe [0282]
.phi..sub.3: a slant angle of the third interference fringe [0283]
P.sub.1: a pitch of the first interference fringe [0284] P.sub.2: a
pitch of the second interference fringe [0285] P.sub.3: a pitch of
the second interference fringe
[0286] Alternatively, in some embodiment, the following
relationship may be satisfied:
.lamda..sub.1<.lamda..sub.3<.lamda..sub.2
[0287] Herein,
[0288] .lamda..sub.1: a peak wavelength of light which is incident
on the light guide plate and is deflected by the first hologram
diffraction grating
[0289] .lamda..sub.2: a peak wavelength of light which is incident
on the light guide plate and is deflected by the second hologram
diffraction grating
[0290] .lamda..sub.3: a peak wavelength of light which is deflected
by the first hologram diffraction grating and the second hologram
diffraction grating, propagates an inner portion of the light guide
plate by total reflection, and is deflected by the third hologram
diffraction grating
[0291] Furthermore, the present disclosure may have the following
configurations.
[0292] (1)
[0293] A display device comprising:
[0294] a layer including a first region and a second region,
wherein the first region and the second region are configured to be
visible to a user of the display device; and
[0295] circuitry configured:
[0296] to control displaying a computer generated image on an
optical device overlapping the layer and
[0297] to control a first transmittance of the first region of the
layer to be lower than a second transmittance of the second region
of the layer such that:
[0298] a visibility, through the first region, of the computer
generated image is increased and
[0299] a visibility, through the second region, of an environment
opposite the user relative to the display device is higher than a
visibility, through the first region, of the environment opposite
the user relative to the display device.
[0300] (2)
[0301] The display device of (1), wherein:
[0302] the display device further comprises an input device
configured to receive an input from the user of the display device,
and
[0303] the circuitry is further configured to determine, based on
the input, whether the computer generated image overlaps with the
first region as viewed by the user of the display device.
[0304] (3)
[0305] The display device of (1), further comprising:
[0306] an input device configured to receive an input from the user
of the display device and to adjust, based on the input, a position
of the computer generated image and/or a position of the first
region.
[0307] (4)
[0308] The display device of (1) to (3), wherein:
[0309] the display device further comprises:
[0310] an image forming device configured to emit internal light
based on which a computer generated image is formed;
[0311] a first substrate;
[0312] a plurality of first transparent electrode segments disposed
on a surface of the first substrate, the layer being disposed on a
surface of the first transparent electrode opposite the first
substrate;
[0313] a plurality of second transparent electrode segments
disposed on a surface of the layer opposite the plurality of first
transparent electrode segments; and
[0314] a second substrate disposed opposite the first substrate
relative to the layer,
[0315] the plurality of first transparent electrode segments extend
in a first direction, and
[0316] the plurality of second transparent electrode segments
extend in a second direction different from the first
direction.
[0317] (5)
[0318] The display device of (1) to (4), wherein:
[0319] the layer comprises a stack of electrochromatic material
layers.
[0320] (6)
[0321] The display device of (5), wherein:
[0322] the electrochromatic material layers include:
[0323] a first material layer comprising tungsten trioxide,
molybdenum trioxide, or vanadium pentoxide;
[0324] a second material layer comprising tantalum pentoxide;
and
[0325] a third material layer comprising iridium tin oxide, iridium
oxide, zirconium dioxide, zirconium phosphate, or a Prussian blue
complex.
[0326] (7)
[0327] The display device of (1) to (6), wherein:
[0328] a ratio of a horizontal length of the first region to a
horizontal length of a computer generated image region on which the
computer generated image is displayed is between 1 and 1.5, and
[0329] a ratio of a vertical length of the first region to a
vertical length of the computer generated image region is between 1
and 1.5.
[0330] (8)
[0331] The display device of (1) to (7), wherein:
[0332] the circuitry is configured to control the first
transmittance of the first region based on an illuminance of an
environment surrounding the display device.
[0333] (9)
[0334] The display device of (8), further comprising:
[0335] a sensor configured to measure the illuminance of the
environment surrounding the display device.
[0336] (10)
[0337] The display device of (1) to (9), wherein:
[0338] the display device comprises a head up display device.
[0339] (11)
[0340] The display device of (10), wherein:
[0341] the head up display device is configured to be installed on
a windshield or a cockpit of a vehicle.
[0342] (12)
[0343] The display device of (1) to (9), further comprising:
[0344] a frame configured to be mounted on a head of the user of
the display device.
[0345] (13)
[0346] The display device of (1) to (12), wherein:
[0347] the circuitry is configured to control a light shielding of
the second region to be equal to or less than 95% of a light
shielding of the first region.
[0348] (14)
[0349] The display device of (1) to (12), wherein:
[0350] the circuitry is configured to control a light shielding of
the second region to be equal to or less than 30% of a light
shielding of the first region.
[0351] (15)
[0352] The display device of (1) to (14), wherein:
[0353] the circuitry is configured to control a light shielding of
the first region to be between 35% and 99% of a complete light
shielding of the first region.
[0354] (16)
[0355] A method for controlling transmittance of a display device,
the method comprising:
[0356] controlling a first transmittance of a first region of a
layer of the display device to be lower than a second transmittance
of a second region of the layer of the display device such
that:
[0357] a visibility, through the first region, of a computer
generated image displayed on an optical device overlapping the
layer is increased and
[0358] a visibility, through the second region, of an environment
opposite the user relative to the display device is higher than a
visibility, through the first region, of the environment opposite
the user relative to the display device,
[0359] wherein the first region and the second region are
configured to be visible to a user of the display device.
[0360] (17)
[0361] A computer-readable medium storing instructions that, when
executed by a computer, perform a method for controlling
transmittance of a display device, the method comprising:
[0362] controlling a first transmittance of a first region of a
layer of the display device to be lower than a second transmittance
of a second region of the layer of the display device such
that:
[0363] a visibility, through the first region, of a computer
generated image displayed on an optical device overlapping the
layer is increased and
[0364] a visibility, through the second region, of an environment
opposite the user relative to the display device is higher than a
visibility, through the first region, of the environment opposite
the user relative to the display device,
[0365] wherein the first region and the second region are
configured to be visible to a user of the display device.
[0366] (18)
[0367] The computer-readable medium of (17), wherein the method
further comprises:
[0368] receiving an input from the user of the display device;
and
[0369] determining, based on the input, whether the computer
generated image overlaps with the first region as viewed by the
user of the display device.
[0370] (19)
[0371] The computer-readable medium of (17), wherein the method
further comprises:
[0372] receiving an input from the user of the display device;
and
[0373] adjusting, based on the input, a position of the computer
generated image and/or a position of the first region.
[0374] (20)
[0375] The computer-readable medium of (17) to (19), wherein the
method further comprises:
[0376] controlling the first transmittance of the first region
based on an illuminance of an environment surrounding the display
device.
[0377] (21)
[0378] The computer-readable medium of (20), wherein the method
further comprises:
[0379] measuring the illuminance of the environment surrounding the
display device.
[0380] (22)
[0381] The computer-readable medium of (17) to (21), wherein the
method further comprises:
[0382] controlling a light shielding of the second region to be
equal to or less than 95% of a light shielding of the first
region.
[0383] (23)
[0384] The computer-readable medium of (17) to (21), wherein the
method further comprises:
[0385] controlling a light shielding of the second region to be
equal to or less than 30% of a light shielding of the first
region.
[0386] (24)
[0387] The computer-readable medium of (17) to (23), wherein the
method further comprises:
[0388] controlling a light shielding ratio of the first region to
be between 35% and 99% of a complete light shielding of the first
region.
[0389] [A01] <<Display Apparatus>>
[0390] A display apparatus including:
[0391] (A) a frame which is mounted on a head of an observer;
[0392] (B) an image display device which is attached to the frame;
and
[0393] (C) a light regulating device which regulates a light amount
of external light incident from an outside,
[0394] wherein the image display device includes:
[0395] (a) an image forming device; and
[0396] (b) an optical device which includes a virtual image forming
region where a virtual image is formed based on light emitted from
the image forming device,
[0397] wherein the virtual image forming region of the optical
device overlaps the light regulating device, and
[0398] wherein, when the virtual image is formed in a portion of
the virtual image forming region based on the light emitted from
the image forming device, the light regulating device is controlled
so that a light shielding ratio of a virtual image projection
region of the light regulating device where a projection image of
the virtual image to the light regulating device is included is
higher than a light shielding ratio of the other region of the
light regulating device.
[0399] [A02] The display apparatus described in [A01], wherein, at
the time of operation of the light regulating device, when the
light shielding ratio of the virtual image projection region of the
light regulating device where the projection image of the virtual
image to the light regulating device is included is defined as "1",
the light shielding ratio of the other region of the light
regulating device is 0.95 or less.
[0400] [A03] The display apparatus described in [A01] or [A02],
wherein, at the time of operation of the light regulating device,
the light shielding ratio of the virtual image projection region of
the light regulating device is in a range of 35% to 99%.
[0401] [A04] The display apparatus described in any one of [A01] to
[A03], wherein, before the virtual image is formed in the optical
device based on the light emitted from the image forming device,
the light shielding ratio of the virtual image projection region of
the light regulating device is increased.
[0402] [A05] The display apparatus described in any one of [A01] to
[A04], wherein, in a case where one virtual image in the optical
device is formed based on the light emitted from the image forming
device and, subsequently, a next virtual image different from the
one virtual image is formed, when the area of the virtual image
projection region of the light regulating device corresponding to
the one virtual image is denoted by S.sub.1 and the area of the
virtual image projection region of the light regulating device
corresponding to the next virtual image is denoted by S.sub.2,
[0403] wherein, in a case where S.sub.2/S.sub.1<0.8 or
1<S.sub.2/S.sub.1, the virtual image projection region of the
light regulating device where the next virtual image is formed is a
region of the light regulating device where the projection image of
the next virtual image to the light regulating device is included,
and
[0404] wherein, in a case where
0.8.ltoreq.S.sub.2/S.sub.1.ltoreq.1, the virtual image projection
region of the light regulating device where the next virtual image
is formed is a region of the light regulating device where the
projection image of the one virtual image to the light regulating
device is included.
[0405] [A06] The display apparatus described in any one of [A01] to
[A05], wherein, when a virtual rectangle circumscribing the virtual
image formed in the optical device is considered, the virtual image
projection region of the light regulating device is larger than the
virtual rectangle.
[0406] [A07] The display apparatus described in [A06], wherein,
when lateral and longitudinal lengths of the virtual rectangle
circumscribing the virtual image formed in the optical device are
denoted by L.sub.1-T and L.sub.1-L, respectively, and a shape of
the virtual image projection region of the light regulating device
is defined as a shape of a rectangle having lateral and
longitudinal lengths of L.sub.2-T and L.sub.2-L, the following
relationships are satisfied:
1.0.ltoreq.L.sub.2-T/L.sub.1-T.ltoreq.1.5
1.0.ltoreq.L.sub.2-L/L.sub.1-L.ltoreq.1.5
[0407] [A08] The display apparatus described in any one of [A01] to
[A07], wherein the light regulating device is configured to
include:
[0408] a first substrate;
[0409] a second substrate facing the first substrate;
[0410] a first transparent electrode installed on a facing surface
of the first substrate facing the second substrate;
[0411] a second transparent electrode installed on a facing surface
of the second substrate facing the first substrate; and
[0412] a light regulating layer interposed between the first
transparent electrode and the second transparent electrode.
[0413] [A09] The display apparatus described in [A08],
[0414] wherein the first transparent electrode is configured with a
plurality of strip-shaped first transparent electrode segments
extending in a first direction,
[0415] wherein the second transparent electrode is configured with
a plurality of strip-shaped second transparent electrode segments
extending in a second direction different from the first direction,
and
[0416] wherein control of the light shielding ratio of a portion of
the light regulating device corresponding to an overlap region of
the first transparent electrode segment and the second transparent
electrode segment is performed based on control of voltages applied
to the first transparent electrode segment and the second
transparent electrode segment.
[0417] [B01] The display apparatus described in any one of [A01] to
[A09], further including an illuminance sensor (environment
illuminance measurement sensor) which measures the illuminance of
the environment where the display apparatus is placed, wherein the
light shielding ratio of the light regulating device is controlled
based on a measurement result of the illuminance sensor
(environment illuminance measurement sensor).
[0418] [B02] The display apparatus described in any one of [A01] to
[B01], further including an illuminance sensor (environment
illuminance measurement sensor) which measures the illuminance of
the environment where the display apparatus is placed, so that
luminance of the image formed by the image forming device is
controlled based on a measurement result of the illuminance sensor
(environment illuminance measurement sensor).
[0419] [B03] The display apparatus described in any one of [A01] to
[B02], further including a second illuminance sensor (transmitting
light illuminance measurement sensor) which measures the
illuminance based on the light passing from the external
environment through the light regulating device, so that a light
shielding ratio of the light regulating device is controlled based
on a measurement result of the second illuminance sensor
(transmitting light illuminance measurement sensor).
[0420] [B04] The display apparatus described in any one of [A01] to
[B03], further including a second illuminance sensor (transmitting
light illuminance measurement sensor) which measures the
illuminance based on the light passing from the external
environment through the light regulating device, so that luminance
of the image formed by the image forming device is controlled based
on a measurement result of the second illuminance sensor
(transmitting light illuminance measurement sensor).
[0421] [B05] The display apparatus described in any one of [B03]
and [B04], wherein the second illuminance sensor (transmitting
light illuminance measurement sensor) is disposed to be closer to
the observer side than to the optical device.
[0422] [B06] The display apparatus described in any one of [A01] to
[B05], wherein the light passing through the light regulating
device is colored in a desired color by the light regulating
device.
[0423] [B07] The display apparatus described in [B06], wherein the
color colored by the light regulating device is variable.
[0424] [B08] The display apparatus described in [B06], wherein the
color colored by the light regulating device is fixed.
[0425] [C01] <<Initial Setting Method for Display
Apparatus>>
[0426] An initial setting method for a display apparatus, the
display apparatus including:
[0427] (A) a frame which is mounted on a head of an observer;
[0428] (B) an image display device which is attached to the frame;
and
[0429] (C) a light regulating device which regulates a light amount
of external light incident from an outside,
[0430] wherein the image display device includes:
[0431] (a) an image forming device; and
[0432] (b) an optical device which includes a virtual image forming
region where a virtual image is formed based on light emitted from
the image forming device,
[0433] wherein the virtual image forming region of the optical
device overlaps the light regulating device,
[0434] wherein, when the virtual image is formed in a portion of
the virtual image forming region based on the light emitted from
the image forming device, the light regulating device is controlled
so that a light shielding ratio of a virtual image projection
region of the light regulating device where a projection image of
the virtual image to the light regulating device is included is
higher than a light shielding ratio of the other region of the
light regulating device,
[0435] wherein a virtual image of a test pattern is displayed in
the virtual image forming region of the optical device based on the
test pattern emitted from the image forming device, and the light
shielding ratio of a region of the light regulating device
corresponding to the virtual image of the test pattern is set to be
higher than the light shielding ratio of the other region of the
light regulating device, and
[0436] wherein the virtual image of the test pattern and a high
light shielding ratio region of the light regulating device are
moved relative to each other so that the virtual image of the test
pattern observed by the observer and the high light shielding ratio
region of the light regulating device observed by the observer
overlap each other.
[0437] [C02] The initial setting method for the display apparatus
described in [C01], wherein a position relationship between a
formation position of the virtual image in the optical device and a
position of the virtual image projection region of the light
regulating device is corrected by using as a reference a movement
amount when the virtual image of the test pattern and the high
light shielding ratio region of the light regulating device are
moved relative to each other.
[0438] [C03] The initial setting method for the display apparatus
described in [C01] or [C02], wherein the light shielding ratio of
the other region of the light regulating device at the time of
operation of the light regulating device is determined.
[0439] [C04] The initial setting method for the display apparatus
described in any one of [C01] to [C03], wherein the light shielding
ratio of the virtual image projection region of the light
regulating device at the time of operation of the light regulating
device is determined.
[0440] [C05] The initial setting method for the display apparatus
described in any one of [C01] to [C04], wherein when a virtual
rectangle circumscribing the virtual image formed in the optical
device is considered, lateral and longitudinal lengths of the
virtual rectangle are denoted by L.sub.1-T and L.sub.1-L,
respectively, a shape of the virtual image projection region of the
light regulating device is set to be a shape of a rectangle having
lateral and longitudinal lengths of L.sub.2-T and L.sub.2-L, values
of L.sub.2-T/L.sub.1-T and the L.sub.2-L/L.sub.1-L are
determined.
REFERENCE SIGNS LIST
[0441] 10 Frame [0442] 11 Front portion [0443] 11' Central portion
of front portion [0444] 12 Hinge [0445] 13 Temple [0446] 14
Earpiece [0447] 15 Wiring line (signal line, power line, and the
like) [0448] 16 Headphone unit [0449] 16' Wiring line for headphone
unit [0450] 17 Imaging device [0451] 18 Control device (control
circuit, control unit) [0452] 18A Image information storage device
[0453] 19 Installation member [0454] 20 Observer [0455] 21 Pupil
[0456] 100, 200, 300, 400, 500 Image display device [0457] 111,
111A, 111B, 211 Image forming device [0458] 112 Optical system
(collimator optical system) [0459] 113, 213 Housing [0460] 120,
320, 520 Optical device [0461] 121, 321 Light guide plate [0462]
122, 322 First surface of light guide plate [0463] 123, 323 Second
surface of light guide plate [0464] 124, 125 Portion of light guide
plate [0465] 126, 326 Protection member (protective plate) [0466]
127, 327 Adhesive member [0467] 130 First deflecting unit [0468]
140 Second deflecting unit (virtual image forming region) [0469]
140A, 340A Virtual rectangle circumscribing virtual image formed in
optical device [0470] 330 First deflecting unit (first diffraction
grating member) [0471] 340 Second deflecting unit (second
diffraction grating member, virtual image forming region) [0472]
150 Reflective spatial light modulation device [0473] 151 Liquid
crystal display device (LCD) [0474] 152 Polarizing beam splitter
(PBS) [0475] 153 Light source [0476] 251, 251A, 251B Light source
[0477] 252 Collimator optical system [0478] 253 Scanning unit
[0479] 254 Optical system (relay optical system) [0480] 256 Total
reflection mirror [0481] 521 Transparent member [0482] 530A, 530B
Semi-transparent mirror [0483] 601 Light source [0484] 602 Light
guiding member [0485] 603, 605 Polarizing beam splitter [0486] 604
Liquid crystal display device [0487] 606 1/4-wave plate [0488] 607
Reflecting plate [0489] 611 Image forming device [0490] 612 Light
guiding member [0491] 613 Semi-transparent mirror [0492] 614
Reflecting plate [0493] 621 Image forming device [0494] 622 Prism
[0495] 623, 624 Prism surface [0496] 625 Convex lens [0497] 700
Light regulating device [0498] 701 First substrate [0499] 702 First
transparent electrode [0500] 702A First transparent electrode
segment [0501] 703 Second substrate [0502] 704 Second transparent
electrode [0503] 704A Second transparent electrode segment [0504]
705 Light regulating layer [0505] 705A WO.sub.3 layer [0506] 705B
Ta.sub.2O.sub.5 layer [0507] 705C Ir.sub.XSn.sub.1-XO layer [0508]
706 Protective layer [0509] 707 Sealing member [0510] 708 Adhesive
[0511] 709 Light-shielding-ratio-varying minimum unit region of
light regulating device [0512] 711 Virtual image projection region
of light regulating device [0513] 711A Region of light regulating
device corresponding to virtual image of the test pattern [0514]
712 Other region of light regulating device [0515] 721 Illuminance
sensor (environment illuminance measurement sensor) [0516] 722
Second illuminance sensor (transmitting light illuminance
measurement sensor) [0517] 731, 732, 733 Light shielding member
* * * * *