U.S. patent application number 13/235647 was filed with the patent office on 2012-03-29 for light source device and stereoscopic display.
This patent application is currently assigned to Sony Corporation. Invention is credited to Masaru Minami.
Application Number | 20120075698 13/235647 |
Document ID | / |
Family ID | 45870394 |
Filed Date | 2012-03-29 |
United States Patent
Application |
20120075698 |
Kind Code |
A1 |
Minami; Masaru |
March 29, 2012 |
LIGHT SOURCE DEVICE AND STEREOSCOPIC DISPLAY
Abstract
A light source device includes: a light guide plate having first
and second internal reflection planes facing each other; a first
light source applying first illumination light from a side surface
of the light guide plate into an interior thereof; a second light
source facing the second internal reflection plane, and applying
second illumination light to the second internal reflection plane;
and a reflective member between the second internal reflection
plane and the second light source. The second internal reflection
plane is provided with a total-reflection region allowing the first
illumination light to be reflected in a total-internal-reflection
manner whereas allowing the second illumination light to pass
therethrough, and a scattering region allowing the first
illumination light to be reflected and scattered. The reflective
member is disposed in a position corresponding to the scattering
region, and reflects light having passed through the scattering
region, toward the first internal reflection plane.
Inventors: |
Minami; Masaru; (Kanagawa,
JP) |
Assignee: |
Sony Corporation
Tokyo
JP
|
Family ID: |
45870394 |
Appl. No.: |
13/235647 |
Filed: |
September 19, 2011 |
Current U.S.
Class: |
359/462 ;
362/607 |
Current CPC
Class: |
G02B 6/0043 20130101;
G02B 30/27 20200101; G02B 30/00 20200101; G02B 6/004 20130101; G02B
6/0068 20130101 |
Class at
Publication: |
359/462 ;
362/607 |
International
Class: |
G02B 27/22 20060101
G02B027/22; F21V 13/12 20060101 F21V013/12 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 27, 2010 |
JP |
2010-215533 |
Claims
1. A light source device comprising: a light guide plate having a
first internal reflection plane and a second internal reflection
plane which face each other; a first light source applying first
illumination light from a side surface of the light guide plate
into an interior thereof; a second light source disposed to face
the second internal reflection plane of the light guide plate, and
applying second illumination light to the second internal
reflection plane; and a reflective member disposed between the
second internal reflection plane and the second light source,
wherein the second internal reflection plane is provided with a
total-reflection region and a scattering region, the
total-reflection region allowing the first illumination light to be
reflected in a manner of total-internal-reflection whereas allowing
the second illumination light to pass therethrough, and the
scattering region allowing the first illumination light to be
reflected and scattered, and the reflective member is disposed in a
position corresponding to the scattering region, and reflects light
having passed through the scattering region, toward the first
internal reflection plane.
2. The light source device according to claim 1, wherein the light
guide plate is configured to allow a light ray out of a
total-reflection condition to exit from the first internal
reflection plane, and the scattering region and the reflective
member allow the first illumination light to travel, as the light
ray out of the total-reflection condition, toward the first
internal reflection plane.
3. The light source device according to claim 2, wherein the
total-reflection region allows the second illumination light to
pass therethrough and to travel, as the light ray out of the
total-reflection condition, toward the first internal reflection
plane.
4. The light source device according to claim 1, further
comprising: a transparent substrate disposed between the second
internal reflection plane and the second light source, wherein the
reflective member is disposed, on the transparent substrate, in a
position corresponding to the scattering region.
5. The light source device according to claim 1, wherein the
scattering region is formed by processing a surface of the light
guide plate into a geometry different from that of the
total-reflection region, the surface corresponding to the second
internal reflection plane.
6. The light source device according to claim 5, wherein the
reflective member is disposed on a surface of the scattering
region.
7. The light source device according to claim 1, wherein the
scattering region is formed by disposing, on a surface of the light
guide plate, a light-scattering member made of a material different
from that of the light guide plate, the surface corresponding to
the second internal reflection plane of the light guide plate.
8. The light source device according to claim 7, wherein the
reflective member is disposed on a topside of the light-scattering
member.
9. A light source device comprising: a light guide plate; a first
light source applying first illumination light from a side surface
of the light guide plate; a second light source disposed to face
the light guide plate, and applying second illumination light, and
a reflective member disposed between the light guide plate and the
second light source, wherein the light guide plate has: a
reflection region allowing the first illumination light to be
reflected whereas allowing the second illumination light to pass
therethrough; a scattering region allowing the first illumination
light to be reflected and scattered, and the reflective member
disposed in a position corresponding to the scattering region.
10. The light source device according to claim 9, wherein a surface
of the scattering region is processed into a geometry different
from that of the reflection region.
11. The light source device according to claim 9, wherein a
light-scattering member made of a material different from that of
the light guide plate is disposed on the scattering region.
12. A stereoscopic display comprising: a display section displaying
an image; and a light source device emitting light for image
display to the display section, wherein the light source device
includes: a light guide plate having a first internal reflection
plane and a second internal reflection plane which face each other;
a first light source applying first illumination light from a side
surface of the light guide plate into an interior thereof; a second
light source disposed to face the second internal reflection plane
of the light guide plate, and applying second illumination light to
the second internal reflection plane; and a reflective member
disposed between the second internal reflection plane and the
second light source, the second internal reflection plane is
provided with a total-reflection region and a scattering region,
the total-reflection region allowing the first illumination light
to be reflected in a manner of total-internal-reflection whereas
allowing the second illumination light to pass therethrough, and
the scattering region allowing the first illumination light to be
reflected and scattered, and the reflective member is disposed in a
position corresponding to the scattering region, and reflects light
having passed through the scattering region, toward the first
internal reflection plane.
13. The stereoscopic display according to claim 12, wherein the
display section selectively displays one of an image based on
three-dimensional image data and an image based on two-dimensional
image data by switching, the first light source is controlled to be
in a light-on state in the case where an image based on
three-dimensional image data is displayed on the display section,
and is controlled to be in a light-off state or in a light-on state
in the case where an image based on two-dimensional image data is
displayed on the display section, and the second light source is
controlled to be in a light-off state in the case where the image
based on the three-dimensional image data is displayed on the
display section, and is controlled to be in a light-on state in the
case where the image based on the two-dimensional image data is
displayed on the display section.
Description
BACKGROUND
[0001] The present technology relates to a light source device and
a stereoscopic display capable of achieving stereoscopic vision by
a parallax barrier system.
[0002] In related art, as one of stereoscopic display systems which
are allowed to achieve stereoscopic vision with naked eyes without
wearing special glasses, a parallax barrier system stereoscopic
display is known. FIG. 13 illustrates a typical configuration
example of the parallax barrier system stereoscopic display. In the
stereoscopic display, a parallax barrier 101 is disposed to face a
front surface of a two-dimensional display panel 102. In a typical
configuration of the parallax barrier 101, shielding sections 111
shielding display image light from the two-dimensional display
panel 102 and stripe-shaped opening sections (slit sections) 112
allowing the display image light to pass therethrough are
alternately arranged in a horizontal direction.
[0003] An image based on three-dimensional image data is displayed
on the two-dimensional display panel 102. For example, a plurality
of parallax images including different parallax information,
respectively, are prepared as three-dimensional image data, and
each of the parallax images are separated into, for example, a
plurality of stripe-shaped separated images extending in a vertical
direction. Then, the separated images of the plurality of parallax
images are alternately arranged in a horizontal direction to
produce a composite image including a plurality of stripe-shaped
parallax images in one screen, and the composite image is displayed
on the two-dimensional display panel 102. In the case of the
parallax barrier system, the composite image displayed on the
two-dimensional display panel 102 is viewed through the parallax
barrier 101. When the widths of the separated images to be
displayed, a slit width in the parallax barrier 101 and the like
are appropriately set, in the case where a viewer watches the
stereoscopic display from a predetermined position and a
predetermined direction, light rays from different parallax images
are allowed to enter into left and right eyes 10L and 10R of the
viewer, respectively, through the slit sections 112. Thus, when the
viewer watches the stereoscopic display from a predetermined
position and a predetermined direction, a stereoscopic image is
perceived. To achieve stereoscopic vision, it is necessary for the
left and right eyes 10L and 10R to view different parallax images,
respectively, so two or more parallax images, that is, an image for
right eye and an image for left eye are necessary. In the case
where three or more parallax images are used, multi-view vision is
achievable. When more parallax images are used, stereoscopic vision
in response to changes in viewing position of the viewer is
achievable. In other words, motion parallax is obtained.
[0004] In the configuration example in FIG. 13, the parallax
barrier 101 is disposed in front of the two-dimensional display
panel 102. For example, in the case where a transparent liquid
crystal display panel is used, the parallax barrier 101 may be
disposed behind the two-dimensional display panel 101 (refer to
FIG. 3 in Japanese Unexamined Patent Application Publication No.
2007-187823). In this case, when the parallax barrier 101 is
disposed between the transparent liquid crystal display panel and a
backlight, stereoscopic display is allowed to be performed based on
the same principle as that in the configuration example in FIG.
13.
SUMMARY
[0005] In stereoscopic displays such as the above-described
stereoscopic display, a display capable of switching from
three-dimensional display to typical two-dimensional display as
necessary to perform not only three-dimensional display but also
two-dimensional display has been developed. For example, FIG. 3 in
Japanese Unexamined Patent Application Publication No. 2007-187823
illustrates a configuration in which a first light source as a
backlight and a first light guide plate, and a second light source
and a second light guide plate are included and a parallax barrier
is disposed between the first light guide plate and the second
light guide plate. In the configuration described in Japanese
Unexamined Patent Application Publication No. 2007-187823, the
first light source and the first light guide plate are used to
perform two-dimensional display, and the second light source, the
second light guide plate and the parallax barrier are used to
perform three-dimensional display. In other words, switching
between two-dimensional display and three-dimensional display is
performed by selectively switching from one of two light sources to
another.
[0006] In the configuration described in Japanese Unexamined Patent
Application Publication No. 2007-187823, a semi-transparent member
is used for the first light guide plate to achieve switching
between two-dimensional display and three-dimensional display.
Therefore, for example, in the case where a reflective film
including a semi-transparent member with a transmittance of 50% is
used, light utilization rates of the first and second light guide
plates are 50%, thereby reducing light use efficiency. Moreover,
for example, in the case where small scattering particles as the
semi-transparent member are included in the first light guide
plate, light having directivity and having passed through the
second light guide plate and a parallax barrier is scattered by the
first light guide plate to cause some issues such as a
deterioration in three-dimensional display quality.
[0007] It is desirable to provide a light source device and a
stereoscopic display capable of preventing a decline in light use
efficiency and performing switching between two-dimensional display
and three-dimensional display without deteriorating display
quality.
[0008] According to an embodiment of the technology, there is
provided a light source device including: a light guide plate
having a first internal reflection plane and a second internal
reflection plane which face each other; a first light source
applying first illumination light from a side surface of the light
guide plate into an interior thereof; a second light source
disposed to face the second internal reflection plane of the light
guide plate, and applying second illumination light to the second
internal reflection plane; and a reflective member disposed between
the second internal reflection plane and the second light source,
in which the second internal reflection plane is provided with a
total-reflection region and a scattering region, the
total-reflection region allowing the first illumination light to be
reflected in a manner of total-internal-reflection whereas allowing
the second illumination light to pass therethrough, and the
scattering region allowing the first illumination light to be
reflected and scattered, and the reflective member is disposed in a
position corresponding to the scattering region, and reflects light
having passed through the scattering region, toward the first
internal reflection plane.
[0009] According to an embodiment of the technology, there is
provided a stereoscopic display including: a display section
displaying an image; and a light source device emitting light for
image display toward the display section, in which the light source
device is configured of the light source device according to the
above-described embodiment of the technology.
[0010] In the light source device or the stereoscopic display
according to the embodiment of the technology, the first
illumination light from the first light source is totally reflected
between the first internal reflection plane and the second internal
reflection plane in an interior of the light guide plate. However,
a part or all of the first illumination light scattered and
reflected by the scattering region on the second internal
reflection plane exits from the first internal reflection plane as
light rays out of a total-reflection condition. In this case, even
if light having passed through the scattering region is present,
the reflective member is disposed in a position corresponding to
the scattering region between the second internal reflection plane
and the second light source; therefore, the light is reflected as a
light ray out of the total-reflection condition toward the first
internal reflection plane. Therefore, the first illumination light
is allowed to be used efficiently. The second illumination light
from the second light source passes through the total-reflection
region on the second internal reflection plane to become a light
ray out of the total-reflection condition on the first internal
reflection plane, and exit from the first internal reflection plane
of the light guide plate. Therefore, the light guide plate is
allowed to have a function as a parallax barrier. In other words,
the light guide plate is allowed to equivalently function as a
parallax barrier with the scattering region as an opening section
(a slit section) and the total-reflection region as a shielding
section for the first illumination light from the first light
source.
[0011] Therefore, when ON (light-on)/OFF (light-off) control of the
first light source and the second light source is appropriately
performed, illumination light for two-dimensional display and
illumination light for three-dimensional display are obtainable.
More specifically, in the case where three-dimensional display is
performed, the first light source is in an ON (light-on) state, and
the second light source is in an OFF (light-off) state. In this
case, the first illumination light scattered and reflected by the
scattering region of the second internal reflection plane of the
light guide plate passes through the first internal reflection
plane of the light guide plate to exit from the light guide plate.
Moreover, in the case where two-dimensional display is performed,
the first light source is in an ON (light-on) state or in an OFF
(light-off) state, and the second light source is in an ON
(light-on) state. In this case, when the second illumination light
from the second light source passes through the total-reflection
region of the second internal reflection plane, the second
illumination light exit from substantially the entire first
internal reflection plane of the light guide plate.
[0012] In the light source device or the stereoscopic display
according to the embodiment of the technology, the scattering
region and the total-reflection region are disposed in the second
internal reflection plane of the light guide plate, and the first
illumination light from the first light source and the second
illumination light from the second light source are allowed to
selectively exit from the light guide plate; therefore, the light
guide plate is allowed to equivalently function as a parallax
barrier. In particular, the reflective member is disposed in a
position corresponding to the scattering region between the second
internal reflection plane of the light guide plate and the second
light source, and light having passed through the scattering region
is reflected toward the first internal reflection plane. Therefore,
while preventing a decline in light use efficiency, illumination
light for two-dimensional display and illumination light for
three-dimensional display are selectively obtainable. Therefore,
while preventing a decline in light use efficiency, switching
between two-dimensional display and three-dimensional display is
allowed to be performed without deteriorating display quality.
[0013] It is to be understood that both the foregoing general
description and the following detailed description are exemplary,
and are intended to provide further explanation of the technology
as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The accompanying drawings are included to provide a further
understanding of the disclosure, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments and, together with the specification, serve to explain
the principles of the technology.
[0015] FIG. 1 is a sectional view illustrating a configuration
example of a stereoscopic display according to a first embodiment
of the technology with a state of emission of light rays from a
light source device in the case where only a first light source is
in an ON (light-on) state.
[0016] FIG. 2 is a sectional view illustrating a configuration
example of the stereoscopic display illustrated in FIG. 1 with a
state of emission of light rays from the light source device in the
case where only a second light source is in an ON (light-on)
state.
[0017] FIG. 3 is a sectional view illustrating a configuration
example of the stereoscopic display illustrated in FIG. 1 with a
state of emission of light rays from the light source device in the
case where both of the first light source and the second light
source are in an ON (light-on) state.
[0018] FIGS. 4A and 4B are a sectional view illustrating a first
configuration example of a light guide plate surface in the
stereoscopic display illustrated in FIG. 1, and a schematic
explanatory diagram illustrating scattering/reflection states of
light rays on the light guide plate surface illustrated in FIG. 4A,
respectively.
[0019] FIGS. 5A and 5B are a sectional view illustrating a second
configuration example of the light guide plate surface in the
stereoscopic display illustrated in FIG. 1, and a schematic
explanatory diagram illustrating scattering/reflection states of
light rays on the light guide plate surface illustrated in FIG. 5A,
respectively.
[0020] FIGS. 6A and 6B are a sectional view illustrating a third
configuration example of the light guide plate surface in the
stereoscopic display illustrated in FIG. 1, and a schematic
explanatory diagram illustrating scattering/reflection states of
light rays on the light guide plate surface illustrated in FIG. 6A,
respectively.
[0021] FIG. 7 is a plot illustrating an example of an intensity
distribution of light observed on a display section side and a
second light source side in the case where only the first light
source in the light source device illustrated in FIG. 1 is in an ON
(light-on) state.
[0022] FIG. 8 is a sectional view illustrating a configuration
example of a stereoscopic display according to a second embodiment
of the technology with a state of emission of light rays from a
light source device in the case where only a first light source is
in an ON (light-on) state.
[0023] FIGS. 9A and 9B are a sectional view illustrating a first
configuration example in the case where a light guide plate surface
in the stereoscopic display illustrated in FIG. 8 is processed into
a recessed shape, and an explanatory diagram illustrating a second
configuration example in the case where the light guide plate
surface is processed into a recessed shape.
[0024] FIG. 10 is a sectional view illustrating a configuration
example in the case where the light guide plate surface in the
stereoscopic display illustrated FIG. 8 is processed into a
projected shape.
[0025] FIGS. 11A and 11B are a sectional view illustrating a first
configuration example in the case where a different member is
disposed on the light guide plate surface in the stereoscopic
display illustrated in FIG. 8 and an explanatory diagram
illustrating a second configuration example in the case where a
different member is disposed on the light guide plate surface.
[0026] FIG. 12 is an explanatory diagram illustrating a
configuration of a stereoscopic display of a comparative example
relative to the stereoscopic display illustrated in FIG. 1.
[0027] FIG. 13 is a configuration diagram illustrating a typical
configuration example of a parallax barrier system stereoscopic
display.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] Preferred embodiments of the technology will be described in
detail below referring to the accompanying drawing
First Embodiment
Whole Configuration of Stereoscopic Display
[0029] FIGS. 1 to 3 illustrate a configuration example of a
stereoscopic display according to a first embodiment of the
technology. The stereoscopic display includes a display section 1
which displays an image and a light source device which is disposed
on a back surface of the display section 1 and emits light for
image display toward the display section 1. The light source device
includes a first light source 2 (a 2D/3D-display light source), a
light guide plate 3, a second light source 4 (2D-display light
source) and a transparent substrate 5. The light guide plate 3 has
a first internal reflection plane 3A facing the display section 1
and a second internal reflection plane 3B facing the second light
source 4. It is to be noted that the stereoscopic display includes
a control circuit for the display section 1 or the like which is
necessary for display; however, the control circuit or the like has
the same configuration as that of a typical control circuit for
display or the like, and will not be described herein. Moreover,
the light source device includes a control circuit (not
illustrated) performing ON (light-on)/OFF (light-off) control of
the first light source 2 and the second light source 4.
[0030] The stereoscopic display is allowed to selectively perform
switching between a two-dimensional (2D) display mode on an entire
screen and a three-dimensional (3D) display mode on the entire
screen as necessary. Switching between the two-dimensional display
mode and the three-dimensional display mode is allowed to be
performed by switching control of image data to be displayed on the
display section 1 and ON/OFF switching control of the first light
source 2 and the second light source 4. FIG. 1 schematically
illustrates a state of emission of light rays from the light source
device in the case where only the first light source 2 is in an ON
(light-on) state, and corresponds to the three-dimensional display
mode. FIG. 2 schematically illustrates a state of emission of light
rays from the light source device in the case where only the second
light source 4 is in an ON (light-on) state, and corresponds to the
two-dimensional display mode. Moreover, FIG. 3 schematically
illustrates a state of emission of light rays from the light source
device in the case where both of the first light source 2 and the
second light source 4 are in an ON (light-on) state, and
corresponds to the two-dimensional display mode.
[0031] The display section 1 is configured with use of a
transmissive two-dimensional display panel, for example, a
transmissive liquid crystal display panel, and includes a plurality
of pixels configured of, for example, R (red) pixels, G (green)
pixels and B (blue) pixels, and the plurality of pixels are
arranged in a matrix form. The display section 1 displays a
two-dimensional image by modulating light from the light source
device from one pixel to another based on image data. The display
section 1 selectively displays one of an image based on
three-dimensional image data and an image based on two-dimensional
image data as necessary by switching. It is to be noted that the
three-dimensional image data is, for example, data including a
plurality of parallax images corresponding to a plurality of
viewing angle directions in three-dimensional display. For example,
in the case where binocular three-dimensional display is performed,
the three-dimensional image data is data including parallax images
for right-eye display and left-eye display. In the case where
three-dimensional display mode display is performed, as in the case
of a parallax barrier system stereoscopic display in related art
illustrated in FIG. 13, for example, a composite image including a
plurality of stripe-shaped parallax images in one screen is
produced and displayed.
[0032] The first light source 2 is configured with use of, for
example, a fluorescent lamp such as a CCFL (Cold Cathode
Fluorescent Lamp), or an LED (Light Emitting Diode). The first
light source 2 applies first illumination light L1 (refer to FIG.
1) from a side surface of the light guide plate 3 into an interior
thereof. One or more first light sources 2 are disposed on a side
surface of the light guide plate 3. For example, in the case where
the light guide plate 3 has a rectangular planar shape, the light
guide plate 3 has four side surfaces, and it is only necessary to
arrange the first light source 2 on one or more of the four side
surfaces. FIG. 1 illustrates a configuration example in which the
first light source 2 is disposed on each of two side surfaces
facing each other of the light guide plate 3. ON/OFF control of the
first light source 2 is performed in response to switching between
the two-dimensional display mode and the three-dimensional display
mode. More specifically, in the case where the display section 1
displays an image based on the three-dimensional image data (in the
case of the three-dimensional display mode), the first light source
2 is controlled to be in a light-on state, and in the case where
the display section 1 displays an image based on the
two-dimensional image data (in the case of the two-dimensional
display mode), the first light source 2 is controlled to be in a
light-off state or a light-on state.
[0033] The second light source 4 is disposed to face the second
internal reflection plane 3B of the light guide plate 3. The second
light source 4 externally applies second illumination light toward
the second internal reflection plane 3B (refer to FIGS. 2 and 3).
The second light source 4 may be a planar light source emitting
light with uniform in-plane luminance, and the configuration
thereof is not specifically limited, and the second light source 4
may be configured with use of a commercially available planar
backlight. For example, a configuration using a light-emitting body
such as a CCFL or an LED and a light-scattering plate for
equalizing in-plane luminance, or the like is considered. ON
(light-on)/OFF (light-off) control of the second light source 4 is
performed in response to switching between the two-dimensional
display mode and the three-dimensional display mode. More
specifically, in the case where the display section 1 displays an
image based on the three-dimensional image data (in the case of the
three-dimensional display mode), the second light source 4 is
controlled to be in a light-off state, and in the case where the
display section 1 displays an image based on the two-dimensional
image data (in the case of the two-dimensional display mode), the
second light source 4 is controlled to be in a light-on state.
[0034] The light guide plate 3 is configured of a transparent
plastic plate of, for example, an acrylic resin. All surfaces
except for the second internal reflection plane 3B of the light
guide plate 3 are entirely transparent. For example, in the case
where the light guide plate 3 has a rectangular planar shape, the
first internal reflection plane 3A and four side surfaces are
entirely transparent.
[0035] The entire first internal reflection plane 3A is
mirror-finished, and allows light rays incident at an incident
angle satisfying a total reflection condition to be reflected, in a
manner of total-internal-reflection, in the interior of the light
guide plate 3 and allows light rays out of the total-reflection
condition to exit therefrom.
[0036] The second internal reflection plane 3B has a scattering
region 31 and a total-reflection region 32. As will be described
later, the scattering region 31 is formed by laser processing,
sandblast processing or coating on a surface of the light guide
plate 3 or bonding a sheet-like light-scattering member on the
surface of the light guide plate 3. In the second internal
reflection plane 3B, in the three-dimensional display mode, the
scattering region 31 and the total-reflection region 32 function as
an opening section (a slit section) and a shielding section of a
parallax barrier for the first illumination light L1 from the first
light source 2, respectively. In the second internal reflection
plane 3B, the scattering region 31 and the total-reflection region
32 are arranged in a pattern forming a configuration corresponding
to a parallax barrier. In other words, the total-reflection region
32 is arranged in a pattern corresponding to a shielding section in
the parallax barrier, and the scattering region 31 is arranged in a
pattern corresponding to an opening section in the parallax
barrier. As a barrier pattern of the parallax barrier, for example,
a stripe pattern in which a large number of vertically long
slit-like opening sections are arranged in parallel with shielding
sections in between is known. However, as the barrier pattern, any
of various known barrier patterns in related art may be used, and
the barrier pattern is not specifically limited.
[0037] The first internal reflection plane 3A and the
total-reflection region 32 of the second internal reflection plane
3B reflect light rays incident at an incident angle .theta.1
satisfying a total reflection condition in a manner of
total-internal-reflection (reflect light rays incident at the
incident angle .theta.1 larger than a predetermined critical angle
.alpha. in a manner of total-internal-reflection). Therefore, the
first illumination light L1 incident from the first light source 2
at the incident angle .theta.1 satisfying the total reflection
condition is guided to a side surface direction by internal total
reflection between the first internal reflection plane 3A and the
total-reflection region 32 of the second internal reflection plane
3B. Moreover, as illustrated in FIG. 2 or FIG. 3, the
total-reflection region 32 allows the second illumination light
from the second light source 4 to pass therethrough to emit the
second illumination light as a light ray out of the
total-reflection condition toward the first internal reflection
plane 3A.
[0038] It is to be noted that the critical angle .alpha. is
represented as follow, where the refractive index of the light
guide plate 3 is n1, and the refractive index of a medium (an air
layer) outside the light guide plate 3 is n0 (<n1). The angles
.alpha. and .theta.1 are angles with respect to a normal to a
surface of the light guide plate. The incident angle .theta.1
satisfying the total reflection condition is
.theta.1>.alpha..
sin .alpha.=n0/n1
[0039] As illustrated in FIG. 1, the scattering region 31 scatters
and reflects the first illumination light L1 from the first light
source 2 and emits partial light L2 of the first illumination light
L1 toward the first internal reflection plane 3A as a light ray out
of the total-reflection condition.
[0040] The transparent substrate 5 is disposed between the second
internal reflection plane 3B and the second light source 4. The
transparent substrate 5 is configured of, for example, a glass
substrate, and a reflection region 51 is disposed on a surface
thereof in a position corresponding to the scattering region 31 in
the light guide plate 3. In the transparent substrate 5, a region
except for the reflection region 51 is a transparent region 52. The
size of the reflection region 51 is preferably equal to or slightly
larger than that of the scattering region 31. The reflection region
51 is preferably in proximity to the scattering region 31 (is in
full contact with the scattering region 31 or is disposed to face
the scattering region 31 with a slight space in between). In the
reflection region 51, a high-reflectivity reflective member is
disposed by, for example, printing or evaporation. As the
reflective member disposed on the reflection region 51, for
example, a regular reflective material such as silver or an
irregular reflective material such as barium sulfate may be
used.
[0041] In the case where the transparent substrate 5 (the
reflection region 51) is not disposed as illustrated in a
comparative example in FIG. 12, in the light guide plate 3, partial
light of the first illumination light L1 becomes light L3 having
passed through the scattering region 31. Therefore, light use
efficiency is reduced, and the light L3 is reflected from a surface
or the like of the second light source 4 to be returned to the
light guide plate 3, thereby exiting from the light guide plate 3
as unintended emission light. In the case where three-dimensional
display is performed, such unintended emission light causes the
occurrence of so-called crosstalk in which the unintended emission
light is perceived as a mixed image of a left-eye image and a
right-eye image. On the other hand, as illustrated in FIG. 1, the
reflection region 51 of the transparent substrate 5 reflects the
light L3 having passed through the scattering region 31 toward the
first internal reflection plane 3A. The reflection region 51 is
disposed in a position corresponding to and in proximity to the
scattering region 31 of the light guide plate 3; therefore, the
light L3 having passed through the scattering region 31 is allowed
to be reflected toward the first internal reflection plane 3A as
light equivalent to the light L2 scattered and reflected by the
scattering region 31, that is, effective light for
three-dimensional display.
[Specific Configuration Example of Scattering Region 31]
[0042] FIG. 4A illustrates a first configuration example of the
second internal reflection plane 3B in the light guide plate 3.
FIG. 4B schematically illustrates reflection and scattering states
of light rays on the second internal reflection plane 3B in the
first configuration example illustrated in FIG. 4A. In the first
configuration example, the scattering region 31 is a recessed
scattering region 31A with respect to the total-reflection region
32. Such a recessed scattering region 31A is allowed to be formed
by, for example, sandblast processing or laser processing. For
example, a surface of the light guide plate 3 is minor-finished,
and then a portion corresponding to the scattering region 31A is
subjected to laser processing to form the scattering region 31A. In
the first configuration example, first illumination light L11
incident from the first light source 2 at the incident angle
.theta.1 satisfying the total reflection condition is reflected in
a manner of total-internal-reflection by the total-reflection
region 32 of the second internal reflection plane 3B. On the other
hand, even if light enters the recessed scattering region 31A at
the same incident angle .theta.1 as in the case where light enters
the total-reflection region 32, some light rays of first
illumination light L12 having entered the recessed scattering
region 31A do not satisfy the total reflection condition on a side
surface portion 33 of a recessed shape, and are scattered and pass
through the side surface portion 33, and other light rays are
scattered and reflected. As illustrated in FIG. 1, some or all of
light rays scattered and reflected are emitted as light rays L2 out
of the total-reflection condition toward the first internal
reflection plane 3A. Moreover, as illustrated in FIG. 1, light
scattered and having passed through the side surface portion 33 is
emitted as a light ray L3 out of the total-reflection condition
toward the first internal reflection plane 3A by the reflection
region 51 of the transparent substrate 5.
[0043] FIG. 5A illustrates a second configuration example of the
second internal reflection plane 3B of the light guide plate 3.
FIG. 5B schematically illustrates reflection and scattering states
of light rays on the second internal reflection plane 3B in the
second configuration example in FIG. 5A. In the second
configuration example, the scattering region 31 is a projected
scattering region 31B with respect to the total-reflection region
32. Such a projected scattering region 31B is allowed to be formed,
for example, by molding a surface of the light guide plate 3 by a
die. In this case, a portion corresponding to the total-reflection
region 32 is minor-finished by a surface of the die. In the second
configuration example, the first illumination light L11 incident
from the first light source 2 at the incident angle .theta.1
satisfying the total reflection condition is reflected in a manner
of total-internal-reflection by the total-reflection region 32 of
the second internal reflection plane 3B. On the other hand, even if
light enters the projected scattering region 31B at the same
incident angle .theta.1 as in the case where light enters the
total-reflection region 32, some light rays of the first
illumination light L12 having entered the projected scattering
region 31B do not satisfy the total reflection condition on a side
surface portion 34 of a projected shape, and are scattered and pass
through the side surface portion 34, and other light rays are
scattered and reflected. As illustrated in FIG. 1, some or all
light rays scattered and reflected are emitted as light rays L2 out
of the total-reflection condition toward the first internal
reflection plane 3A. Moreover, as illustrated in FIG. 1, light
scattered and having passed through the side surface portion 34 is
emitted as a light ray L3 out of the total-reflection condition
toward to the first internal reflection plane 3A by the reflection
region 51 of the transparent substrate 5.
[0044] FIG. 6A illustrates a third configuration example of the
second internal reflection plane 3B of the light guide plate 3.
FIG. 6B schematically illustrates the reflection and scattering
states of light rays on the second internal reflection plane 3B in
the third configuration example illustrated in FIG. 6A. In the
configuration examples in FIGS. 4A and 5A, the surface of the light
guide plate 3 is processed into a geometry different from that of
the total-reflection region 32 to form the scattering region 31. On
the other hand, in a scattering region 31C in the configuration
example in FIG. 6A, instead of processing the surface of the light
guide plate 3, a light-scattering member 35 made of a material
different from that of the light guide plate 3 is disposed on a
surface, corresponding to the second internal reflection plane 3B,
of the light guide plate 3. In this case, a white paint (for
example, barium sulfate) as the light-scattering member 35 is
patterned on the surface of the light guide plate 3 by screen
printing to form the scattering region 31C. In the third
configuration example, the first illumination light L11 incident
from the first light source 2 at the incident angle .theta.1
satisfying the total reflection condition is reflected by the
total-reflection region 32 on the second internal reflection plane
3B in a manner of total-internal-reflection. On the other hand,
even if light enters the scattering region 31C where the
light-scattering member 35 is disposed at the same incident angle
.theta.1 as in the case where light enters the total-reflection
region 32, a part of the first illumination light L12 having
entered the scattering region 31C is scattered and passes through
the scattering region 31C by the light-scattering member 35, and
the other is scattered and reflected. Some or all of light rays
scattered and reflected are emitted as light rays out of the
total-reflection condition toward the first internal reflection
plane 3A. Moreover, as illustrated in FIG. 1, light scattered and
having passed through the scattering region 31C is emitted as a
light ray L3 out of the total-reflection condition toward the first
internal reflection plane 3A by the reflection region 51 of the
transparent substrate 5.
[Operation of Stereoscopic Display]
[0045] In the case where the stereoscopic display performs
three-dimensional display mode display, the display section 1
displays an image based on the three-dimensional image data, and ON
(light-on)/OFF (light-off) control of the first light source 2 and
the second light source 4 is performed for three-dimensional
display. More specifically, as illustrated in FIG. 1, the first
light source 2 is controlled to be in an ON (light-on) state, and
the second light source 4 is controlled to be in an OFF (light-off)
state. In this state, the first illumination light L1 from the
first light source 2 is reflected repeatedly in a manner of
total-internal-reflection between the first internal reflection
plane 3A and the total-reflection region 32 of the second internal
reflection plane 3B in the light guide plate 3 to be guided and
emitted from a side surface where the first light source 2 is
disposed to the other side surface facing the side surface. On the
other hand, a part of the first illumination light L1 from the
first light source 2 is scattered and reflected from the scattering
region 31 of the light guide plate 3 to pass through the first
internal reflection plane 3A of the light guide plate 3 and exit
from the light guide plate 3. Therefore, the light guide plate 3 is
allowed to have a function as a parallax barrier. In other words,
for the first illumination light L1 from the first light source 2,
the light guide plate 3 is allowed to equivalently function as a
parallax barrier with the scattering region 31 as an opening
section (slit section) and the total-reflection region 51 as a
shielding section. Therefore, three-dimensional display by a
parallax barrier system in which the parallax barrier is
equivalently disposed on a back surface of the display section 1 is
performed. Moreover, in the embodiment, even if light L3 scattered
and having passed through the scattering region 31 is present in
the light guide plate 3, a reflective member (the reflection region
51 of the transparent substrate 5) is disposed in a position
corresponding to the scattering region 31 between the second
internal reflection plane 3B and the second light source 4;
therefore, the light L3 having passed through the scattering region
31 is reflected toward the first internal reflection plane 3A as a
light ray out of the total-reflection condition. Therefore, the
first illumination light L1 is allowed to be used efficiently as
effective light for three-dimensional display.
[0046] On the other hand, in the case where two-dimensional display
mode display is performed, the display section 1 displays an image
base on the two-dimensional image data, and ON (light-on)/OFF
(light-off) control of the first light source 2 and the second
light source 4 is performed for two-dimensional display. More
specifically, for example, as illustrated in FIG. 2, the first
light source 2 is controlled to be in an OFF (light-off) state, and
the second light source 4 is controlled to be in an ON (light-on)
state. In this case, second illumination light from the second
light source 4 passes through the total-reflection region 32 of the
second internal reflection plane 3B to exit as a light ray out of
the total-reflection condition from substantially the entire first
internal reflection plane 3A. In other words, the light guide plate
3 functions as a planar light source similar to a typical
backlight. Therefore, two-dimensional display by a backlight system
in which a typical backlight is equivalently disposed on a back
surface of the display section 1 is performed.
[0047] When only the second light source 4 is turned on, the second
illumination light is emitted from substantially the entire surface
of the light guide plate 3, and if necessary, the first light
source 2 may be turned on as illustrated in FIG. 3. Therefore, for
example, in the case where there is a difference in a luminance
distribution between portions corresponding to the scattering
region 31 and the total-reflection region 32 in a state where only
the second light source 4 emits light, the lighting state of the
first light source 2 is appropriately adjusted (ON/OFF control or
the lighting amount of the first light source 2 is adjusted),
thereby allowing the luminance distribution in an entire surface to
be optimized. However, for example, in the case where luminance is
sufficiently corrected in the display section 1 in two-dimensional
display, it is only necessary for only the second light source 4 to
be turned on.
[0048] FIG. 7 illustrates a simulation result of a light intensity
distribution (orientation angle characteristics) in the case where
the light source device of the stereoscopic display illustrated in
FIG. 1 is in a state corresponding to the three-dimensional display
(a state where the first light source 2 is in an ON (light-on)
state and the second light source 4 is in an OFF (light-off)
state). In FIG. 7, as a comparative example, a simulation result of
a light intensity distribution in a configuration in which a
reflective member (the transparent substrate 5) is not disposed
between the second internal reflection plane 3B and the second
light source 4 (refer to FIG. 12) is illustrated. In FIG. 7, a
horizontal axis indicates angle (where a direction orthogonal to a
light emission surface is 0.degree.) and a vertical axis indicates
standardized light intensity (arbitrary unit (a.u.)). As a
simulation condition, the size of a pattern of the scattering
region 31 in the light guide plate 3 and the size of a pattern of
the reflection region 51 in the transparent substrate 5 are equal
to each other. Moreover, the reflection region 51 is disposed
directly below the scattering region 31 (the scattering region 31
and the reflection region 51 are not in contact with each other). A
regular reflective material with a reflectivity of 90% is used for
the reflection region 51. The light intensity on the vertical axis
is standardized with reference to a maximum light amount of light
emitted from the light guide plate 3 to the display section 1 in a
state where a reflective member (the transparent substrate 5) is
not disposed.
[0049] In FIG. 7, a curve with a reference numeral 61 indicates the
intensity of light emitted to the display section 1 in the
configuration illustrated in FIG. 1, and a curve with a reference
numeral 62 indicates the intensity of light emitted to the second
light source 4 in the configuration illustrated in FIG. 1. A curve
with a reference numeral 64 indicates the intensity of light
emitted to the display section 1 in a configuration of the
comparative example illustrated in FIG. 12, and a curve with a
reference numeral 63 indicates the intensity of light emitted to
the second light source 4 in the configuration of the comparative
example illustrated in FIG. 12. As is evident from the curve 61 and
the curve 64, in the light source device according to the
embodiment, a light amount equal to approximately twice the light
amount obtained by the light source device of the comparative
example is obtained on the display section 1 side. Moreover, as is
evident from the curve 62 and the curve 63, in the light source
device of the comparative example, a large amount of light is
emitted to the second light source 4; however, in the light source
device according to the embodiment, light is hardly emitted to the
second light source 4. In other words, it is obvious that light use
efficiency is high.
[0050] As described above, in the stereoscopic display using the
light source device according to the embodiment, the scattering
region 31 and the total-reflection region 32 are disposed in the
second internal reflection plane 3B of the light guide plate 3, and
the first illumination light from the first light source 2 and the
second illumination light from the second light source 4 are
allowed to selectively exit from the light guide plate 3;
therefore, the light guide plate 3 is allowed to equivalently
function as a parallax barrier. In particular, a reflective member
(the reflection region 51 of the transparent substrate 5) is
disposed in a position corresponding to the scattering region 31
between the second internal reflection plane 3B of the light guide
plate 3 and the second light source 4 to reflect light having
passed through the scattering region 31 to the first internal
reflection plane 3A; therefore, while preventing a decline in light
use efficiency, illumination light for two-dimensional display and
illumination light for three-dimensional display are allowed to be
selectively obtained. Therefore, while preventing a decline in
light use efficiency, switching between two-dimensional display and
three-dimensional display is allowed to be performed without
deteriorating display quality. Moreover, the reflection region 51
is disposed in a position corresponding to and in proximity to the
scattering region 31 of the light guide plate 3; therefore, light
L3 having passed through the scattering region 31 is allowed to be
reflected toward the first internal reflection plane 3A as light
equivalent to light L2 scattered and reflected by the scattering
region 31, that is, effective light for three-dimensional display.
Therefore, the light L3 having passed through the scattering region
31 is allowed to be prevented from being emitted to an unintended
direction, and the occurrence of crosstalk is preventable
accordingly.
Second Embodiment
[0051] Next, a stereoscopic display according to a second
embodiment of the technology will be described below. It is to be
noted that like components are denoted by like numerals as of the
stereoscopic display according to the first embodiment and will not
be further described.
[0052] FIG. 8 illustrates a configuration example of the
stereoscopic display according to the second embodiment of the
technology. The stereoscopic display according to the embodiment
has the same configuration as that of the stereoscopic display in
FIG. 1, except that the transparent substrate 5 in the light source
device is not included. Instead of the transparent substrate 5, a
reflective member is disposed in a position corresponding to the
scattering region 31 in the second internal reflection plane 3B of
the light guide plate 3.
[0053] FIGS. 9A and 9B illustrate a configuration example in which
in the case where the second internal reflection plane 3B of the
light guide plate 3 has the recessed scattering region 31A as in
the case of the configuration example in FIGS. 4A and 4B, a
reflective member is disposed on the recessed scattering region
31A. In the configuration example in FIG. 9A, as the reflective
member, a reflective film 36 made of a high-reflectivity material
is formed on a surface of the recessed scattering region 31A by,
for example, evaporation. In the configuration example in FIG. 9B,
a high-reflectivity material 37 as a reflective member is filled in
the recessed scattering region 31A by, for example, screen
printing, thereby allowing an entire surface of the recessed
scattering region 31A to be covered therewith.
[0054] FIG. 10 illustrates a configuration example in which in the
case where the second internal reflection plane 3B of the light
guide plate 3 has the projected scattering region 31B as in the
case of the configuration example in FIGS. 5A and 5B, a reflective
member is disposed on the projected scattering region 31B. In this
configuration example, as the reflective member, a reflective film
36 made of a high-reflectivity material is formed on a surface of
the projected scattering region 31B by, for example,
evaporation.
[0055] FIG. 11A illustrates a configuration example in which in the
case where the light-scattering member 35 made of a different
material from the material of the light guide plate 3 is disposed
on a surface of the second internal reflection plane 3B of the
light guide plate 3 as in the case of the configuration example in
FIGS. 6A and 6B, a reflective member is disposed on the
light-scattering member 35. In this configuration example, as the
reflective member, a reflective film 36 made of a high-reflectivity
material is formed on a surface of the light-scattering member 35
by, for example, screen printing. Moreover, in a configuration
example in FIG. 11B, a thickness d of the light-scattering member
35 is increased to allow the light-scattering member 35 to have a
function as a reflective member. As long as the reflectivity of the
light-scattering member 35 is high, a configuration illustrated in
FIG. 11B may be applicable.
[0056] In the stereoscopic display using the light source device
according to the embodiment, a reflective member is directly
disposed in a position corresponding to the scattering region 31 of
the second internal reflection plane 3B of the light guide plate 3
without arranging the transparent substrate 5 between the second
internal reflection plane 3B and the second light source 4;
therefore, the number of components is reduced, compared to the
stereoscopic display in FIG. 1, and space saving is achievable.
[0057] The present application contains subject matter related to
that disclosed in Japanese Priority Patent Application 2010-215533
filed in the Japan Patent Office on Sep. 27, 2010, the entire
content of which is hereby incorporated by reference.
[0058] It should be understood by those skilled in the art that
various modifications, combinations, sub-combinations and
alterations may occur depending on design requirements and other
factors insofar as they are within the scope of the appended claims
or the equivalents thereof.
* * * * *