U.S. patent application number 14/969111 was filed with the patent office on 2016-04-07 for image display device, electronic apparatuse using the same, display output control method for image display device, and output control program thereof.
This patent application is currently assigned to NLT TECHNOLOGIES, LTD.. The applicant listed for this patent is NLT TECHNOLOGIES, LTD.. Invention is credited to Koji MIMURA, Ken SUMIYOSHI.
Application Number | 20160097943 14/969111 |
Document ID | / |
Family ID | 45328210 |
Filed Date | 2016-04-07 |
United States Patent
Application |
20160097943 |
Kind Code |
A1 |
MIMURA; Koji ; et
al. |
April 7, 2016 |
IMAGE DISPLAY DEVICE, ELECTRONIC APPARATUSE USING THE SAME, DISPLAY
OUTPUT CONTROL METHOD FOR IMAGE DISPLAY DEVICE, AND OUTPUT CONTROL
PROGRAM THEREOF
Abstract
Provided is a display device having a viewing angle changing
function, which is capable of preventing leakage of information
displayed on a display screen even when there is a fault generated
in changing the viewing angle. The image display device including a
viewing angle changing element capable of changing a wide vision
display and a narrow vision display and including a display element
is provided with a detection element which detects a fault
generated in the viewing angle changing element and a module for
changing to a narrow vision display when there is a fault based on
a detection value of the detection element. For example, when there
is a fault, a transparent heater is operated to heat a liquid
crystal layer to set a transparent-scattering changing element to a
transparent state and forcibly set the display device to a narrow
vision display.
Inventors: |
MIMURA; Koji; (Kanagawa,
JP) ; SUMIYOSHI; Ken; (Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NLT TECHNOLOGIES, LTD. |
Kanagawa |
|
JP |
|
|
Assignee: |
NLT TECHNOLOGIES, LTD.
Kanagawa
JP
|
Family ID: |
45328210 |
Appl. No.: |
14/969111 |
Filed: |
December 15, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13164376 |
Jun 20, 2011 |
9244546 |
|
|
14969111 |
|
|
|
|
Current U.S.
Class: |
345/214 |
Current CPC
Class: |
G02F 1/1323 20130101;
G09G 2330/021 20130101; G09G 2320/028 20130101; G06F 3/041
20130101; G09G 3/3603 20130101; G01R 31/50 20200101; G09G 3/36
20130101; G09G 3/2003 20130101 |
International
Class: |
G02F 1/13 20060101
G02F001/13; G09G 3/36 20060101 G09G003/36; G09G 3/20 20060101
G09G003/20 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 21, 2010 |
JP |
2010-141024 |
Mar 10, 2011 |
JP |
2011-052914 |
Claims
1. An image display device, comprising a display device main body
which includes a display element for displaying prescribed image
information to outside and a viewing angle changing element for
setting to change display of image information on the display
element at least from a wide vision display to a narrow vision
display based on a changing command from the outside, wherein: the
display device main body is provided with an operation state
detection element which detects an operation state of the viewing
angle changing element; the viewing angle changing element is
provided with a narrow vision forcible setting module which
operates to forcibly set the display of the display element to a
narrow vision display state by a voltage forcible applying
mechanism which applies a voltage to the viewing angle changing
element, when the operation state detected by the operation state
detection element is a fault state; the operation state detection
element is formed by an electric current detection element which
measures an electric current flown in the viewing angle changing
element; and the fault judging module which judges whether or not
there is a fault generated in the viewing angle changing element
based on an electric current detected value acquired by the
electric current detection element is provided; and the fault
judging module comprises a storage section which stores desired
electric current values flowing to the viewing angle changing
element as reference electric current values, and compares the
reference electric current values stored in the storage section
with the electric current value detected by the electric current
detection element to judge whether or not there is a fault
generated in the viewing angle changing element.
2. The image display device as claimed in claim 1, wherein the
voltage forcible applying mechanism is formed by a pair of
transparent electrodes covered by an insulating layer and insulated
from a voltage applying electrode that is used under a normal state
where no fault is generated.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 13/164,376, filed Jun. 20, 2011, which claims priority to
Japanese Patent Application No. 2010-141024, filed on Jun. 21,
2010, and Japanese Patent Application No. 2011-052914, filed on
Mar. 10, 2011, the disclosure of which is incorporated herein in
its entirety by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an image display device
capable of changing a wide vision display and narrow vision
display, an electronic apparatus using the same, a display output
control method for the image display device, and an output control
program thereof.
[0004] 2. Description of the Related Art
[0005] Recently, liquid crystal displays (LCDs) are broadly used
for display elements of general-use display devices such as mobile
phones and notebook personal computers as well as display elements
of ATMs (Automatic Teller Machines) and industrial information
terminal devices used in convenience stores and the like. Due to
the technical developments achieved heretofore, the LCD has no
viewing-angle dependency, and the display thereof can be visually
recognized from every direction. While the mobile terminals such as
the mobile phones and the notebook personal computers are normally
used with a wide vision display, there are many opportunities to
display personal information and secret information thereon in
public places because of their nature as the terminals. Under such
circumstances, there is a demand to limit the viewing angle so as
not be peeped by others. Further, with ATMs and the information
terminal devices placed in convenience stores and the like, the
viewing angle of the display elements are limited by providing a
viewing-angle limiting film on top of the display elements for the
sake of privacy protection and information security.
[0006] In the meantime, there is a demand to use such information
terminal devices as advertisement media by setting those to a wide
viewing angle display when no one is using the devices.
[0007] As described, there has been an increasing demand for making
it possible to change the viewing angles of the display devices
depending on the use conditions thereof regarding various kinds of
display devices.
[0008] For such demands, Japanese Unexamined Patent Publication Hei
11-231794 (paragraphs [0018]-[0020] (Patent Document 1)), for
example, proposes a display technique which is capable of changing
viewing angles. This technique will be described hereinafter by
referring to FIG. 24.
[0009] As shown in FIG. 24, a diffusion device 103, luminance
enhancement films 104 and 105, a unit 110 formed with a louver film
which restricts the spread angles of light, a variable diffusion
cell 111, and an LCD screen 106 are placed on a backlight system
constituted with a line of fluorescent lights 101 and a mirror 102
in a sequentially stacked manner.
[0010] The variable diffusion cell 111 can change a transparent
state and a light scattering state by applying or not applying an
electric field. As the cell, a polymer dispersed liquid crystal
cell or a polymer stabilized cholesteric structure cell can be
used. Through changing the transparent state and the light
scattering state of the variable diffusion cell 111 electrically,
it is possible to change the narrow vision display with which the
display can be viewed only from a narrow angle range and the wide
vision display with which the display can be recognized from a wide
angle range.
[0011] Further, as other related techniques, there are Japanese
Unexamined Patent Publication 2006-323031 (Patent Documents 2),
Japanese Unexamined Patent Publication 2007-233373 (Patent
Documents 3), and Japanese Unexamined Patent Publication
2007-298844 (Patent Documents 4).
[0012] Among those, Patent Document 2 discloses a display device
which includes: a surface light source which emits light on a plane
towards the viewer side; a viewing angle control module provided in
front of the surface light source for increasing the directivity of
transmission light; a changing element provided on the front face
of the viewing angle control module, which is adhesively attached
via an adhesive layer; and a display panel provided in front of the
changing element. Among those, the changing element changes to a
transparent state where incident light is transmitted as it is or
to a semitransparent opaque state where the incident light is let
through by being scattered.
[0013] Further, Patent Document 3 discloses a display device
capable of changing the viewing angle range, which includes: a
light source device that is provided with a transparent-scattering
changing element capable of changing a state for transmitting
incident light and a state for scattering the incident light; and a
transmission-type liquid crystal display panel including pixels for
display arranged in matrix, which drives the transparent-scattering
changing element by using a power supply and signals for driving
the pixels.
[0014] Furthermore, Patent Document 4 discloses a display device
which is constituted with: a lighting angle variable light source
device formed with a backlight functioning as a light source and a
light beam control device; and a transmission type display device.
The light beam control device is provided with a
transparent-scattering element capable of electrically changing
straightforward emission and scattering emission of incident light,
which is stacked on a light beam control film device.
[0015] However, in the variable viewing angle display technique
disclosed in Patent Document 1, there is such a shortcoming that no
measure is taken for a fault that may occur in changing the viewing
angles. That is, there is a possibility of causing leakage of
screen information when the screen turns to the wide vision display
because of a fault when it is intended to be used as the narrow
vision display. Particularly, with the information terminals device
such as the ATM where it is important to keep the security of the
display information, such fault can become a fatal event that may
lose the reliability for the customers.
[0016] Further, since there is also no measure for a fault in
changing the viewing angles taken in the display devices disclosed
in Patent Documents 2, 3, and 4, there is a possibility leaking
screen information when the screen turns to the wide vision display
because of a fault when it is intended to be used as the narrow
vision display.
[0017] The present invention is designed in view of such
circumstances, and it is an exemplary object of the present
invention to provide an image display device which can prevent
leakage of information displayed on the display screen even when
there is a fault generated in the viewing angle changing function,
and to provide an electronic apparatus using the same, a display
output control method for the image display device, and an output
control program thereof.
SUMMARY OF THE INVENTION
[0018] In order to overcome the foregoing issues, the image display
device according to an exemplary aspect of the invention is
characterized as an image display device, including a display
device main body which includes a display element for
outputting/displaying prescribed information to outside and a
viewing angle changing element for setting to change outputted
display of image information on the display element at least from a
wide vision display to a narrow vision display based on a changing
command from the outside, wherein: the display device main body is
provided with an operation state detection element which detects an
operation state of the viewing angle changing element; and the
viewing angle changing element is provided with a narrow vision
forcible setting module which operates to forcibly set the
outputted display of the display element to a narrow vision display
state, when the operation state detected by the operation state
detection element is a fault state.
[0019] Further, in order to overcome the foregoing issues, the
electronic apparatus according to another exemplary aspect of the
invention is characterized to include the above-described image
display device loaded for displaying information.
[0020] Furthermore, in order to overcome the foregoing issues, the
display output control method for the image display device
according to still another exemplary aspect of the invention is
characterized as a method used for an image display device
including a display device main body which includes a display
element for outputting/displaying prescribed image information to
outside and a viewing angle changing element for setting to change
outputted display of image information on the display element at
least from a wide vision display to a narrow vision display based
on a changing command from the outside, and the method includes:
detecting an electric current flowing into the viewing angle
changing element by an electric current detection element provided
to the display device main body; executing comparison processing
for comparing the electric current value detected by the electric
current detection element with an electric current value under a
normal operation measured and stored in advance, and judgment
processing by a fault judging module provided to the display device
main body for judging whether or not there is a fault generated in
the viewing angle changing element based on a result of the
comparison; and setting the output display of the display element
to a narrow vision display state forcibly by a narrow vision
forcible setting module that is provided to the viewing angle
changing element, when it is judged by the fault judging module
that there is a fault.
[0021] Moreover, in order to overcome the foregoing issues, the
display output control program for the image display device
according to still another exemplary aspect of the invention is
characterized as a program used for an image display device
including a display device main body which includes a display
element for outputting/displaying prescribed image information to
outside and a viewing angle changing element for setting to change
outputted display of image information on the display element at
least from a wide vision display to a narrow vision display based
on a changing command from the outside, and the program causes a
computer to execute: a fault judgment processing function which
compares an electric current value detected by an electric current
value detection element for detecting a drive electric current for
the viewing angle changing element with an electric current value
under a normal operation stored in advance, and judges whether or
not there is a fault generated in the viewing angle changing
element based on a result of the comparison; and a narrow vision
forcible changing function which forcibly sets the display of the
display element to a narrow vision display state, when it is judged
by the fault judgment processing function that there is a
fault.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a sectional view showing a first exemplary
embodiment of an image display device according to the present
invention;
[0023] FIGS. 2A and 2B show schematic illustrations of the spread
of light at the time of changing the viewing angle executed in the
image display device shown in FIG. 1, in which FIG. 2A is a narrow
vision display operation and FIG. 2B is a wide vision display
operation;
[0024] FIG. 3 is an explanatory illustration showing a state of
limiting the viewing angles of a micro louver of the image display
device shown in FIG. 1;
[0025] FIG. 4 is a table showing fault modes and states of a
viewing angle changing element of the image display device shown in
FIG. 1;
[0026] FIG. 5 is a graph showing the temperature dependency of the
viewing angle changing element of the image display device shown in
FIG. 1;
[0027] FIG. 6 is a block diagram showing a drive control system of
the image display device shown in FIG. 1;
[0028] FIG. 7 is a flowchart showing a viewing angle changing
processing operation of the image display device shown in FIG.
1;
[0029] FIG. 8 is a sectional view showing a second exemplary
embodiment of the image display device according to the present
invention;
[0030] FIG. 9 is a sectional view of a transmission-scattering
changing element of the image display device shown in FIG. 8;
[0031] FIG. 10 is a block diagram showing a drive control system of
the image display device shown in FIG. 8;
[0032] FIG. 11 is a flowchart showing a viewing angle changing
processing operation of the image display device shown in FIG.
8;
[0033] FIG. 12A is a plan view of a transmission-scattering
changing element of an image display device according to a third
exemplary embodiment of the present invention, and FIG. 12B is a
perspective view thereof;
[0034] FIG. 13A is a plan view of a transmission-scattering
changing element of an image display device according to a fourth
exemplary embodiment of the present invention, and FIG. 13B is a
perspective view thereof;
[0035] FIG. 14 is a sectional view showing a fifth exemplary
embodiment of the image display device according to the present
invention;
[0036] FIG. 15 is a block diagram showing a drive control system of
the image display device shown in FIG. 14;
[0037] FIG. 16 is a sectional view showing a sixth exemplary
embodiment of the image display device according to the present
invention;
[0038] FIG. 17 is a sectional view showing a seventh exemplary
embodiment of the image display device according to the present
invention;
[0039] FIG. 18 is a sectional view showing an eighth exemplary
embodiment of the image display device according to the present
invention;
[0040] FIGS. 19A and 19B are illustrations of an oblique louver
provided to the image display device shown in FIG. 18, in which
FIG. 19A is a sectional view showing the main part thereof and FIG.
19B shows a function of the oblique louver shown in FIG. 19A;
[0041] FIG. 20 is a graph showing changes of the transmittance with
respect to the angles of incident light of the oblique louver shown
in FIG. 18;
[0042] FIG. 21 is a flowchart showing a viewing angle changing
processing operation of the image display device shown in FIG.
18;
[0043] FIG. 22 is a sectional view showing a ninth exemplary
embodiment of the image display device according to the present
invention;
[0044] FIG. 23 is a perspective view showing an electronic
apparatus on which the image display device according to the
present invention is loaded; and
[0045] FIG. 24 is a sectional view showing a structure of a
variable viewing angle display of a related technique.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Exemplary Embodiment
[0046] Hereinafter, a first embodiment of an image display device
according to the present invention will be described by referring
to FIG. 1-FIG. 7. As shown in FIG. 1, an image display device 1 is
formed by including at least: a backlight 10 functioning as a
surface light source; a viewing angle changing element 20 provided
on the upper side of the back light 1, which is capable of
electrically changing the viewing angle range (narrow vision field
and wide vision field) of the image display device 1; a transparent
heater 50 provided on the upper side of the viewing angle changing
element 20 for heating the viewing angle changing element 20; and a
non-luminous type display element 60 provided on the upper side of
the transparent heater 50.
[0047] Further, although not shown in FIG. 1, in addition to those,
the image display device 1 is provided with a detection element
(operation state detection element) 70A (see FIG. 6) for monitoring
the state of the viewing angle changing element 20 and with a fault
judging module 75 (see FIG. 6) for judging whether or not there is
a fault generated the viewing angle changing element 20 based on a
detection measurement value (or a detection signal) of the
detection element. Thus, while the illustration of FIG. 1 only
corresponds to the main part of the image display device, the
illustration shown in FIG. 1 is simply considered as the image
display device 1 in the explanations provided hereinafter for easy
understanding.
[0048] Among the above-described structures, the backlight 10 is
formed by including at least: a light source 11 formed as a linear
light source by lining a plurality of light sources made with a
cold cathode tubes or point light sources (e.g., LED (Light
Emitting Diode)) in a straight line; a light guiding plate 13 for
making the light radiated from the light source 11 into a surface
light source; a reflection sheet 12 which reflects the light leaked
from the light guiding plate 13 so that the light makes incident
again to the light guiding plate 13; a diffusion plate 14 for
uniformanizing the luminance within the display surface by
diffusing the light emitted from the light guiding plate 13 towards
the display element 60 side; and prism sheets 15a and 15b for
increasing the front luminance of the display element 60 by
increasing the directivity of the light emitted from the diffusion
plate 14.
[0049] Further, although not shown in FIG. 1, in addition to those,
a reflection type polarization film may be provided on top of the
prism sheets 15a and 15b for improving the front luminance of the
display element 60. A specific example of the reflection type
polarization film may be DBEF (Dual Brightness Enhancement Film)
that is a product of Sumitomo 3M Corporation.
[0050] Furthermore, the form of the backlight 10 is not limited to
the one described above but may be any form, as long as it is a
surface luminance type light source that can be utilized as a
surface light source of the non-luminous type display element
60.
[0051] As shown in FIG. 1, the viewing angle changing element 20 is
formed by including: a micro louver 30 in which a transparent layer
31 and a light shielding layer 32 are alternately disposed; and a
transparent-scattering changing element 40 which changes alignment
of liquid crystal molecules to a transparent state and a scattering
state. Through electrically changing the transparent-scattering
changing element 40 to the transparent state and the scattering
state, the image display device 1 can be set to a narrow vision
display state and a wide vision display state. The
transparent-scattering changing element 40 is formed by including:
a pair of transparent substrates 41 and 42; transparent electrodes
(voltage applying electrodes) 43 and 44 formed on the transparent
substrates; and a polymer dispersed liquid crystal or a polymer
network crystal made with a mixture of a liquid crystal 45 and
polymers 46 sandwiched between the transparent substrates 41 and
42. The transparent-scattering changing element 40 is structured to
be able to apply a voltage to the transparent electrodes 43 and
44.
[0052] Note here that the refractive index of the polymer 46 of the
transparent-scattering changing element 40 is adjusted to be
substantially same as the ordinary light refractive index of the
liquid crystal 45. Thus, in a state where no voltage is applied to
the transparent-scattering changing element 40, molecules of the
liquid crystal 45 are randomly aligned. Therefore, the refractive
index of the liquid crystal 45 becomes higher than the ordinary
light refractive index and becomes unmatched with the refractive
index of the polymer 46. As a result, the polymer dispersed liquid
crystal and the polymer network liquid crystal come to be in a
scattering state. In the meantime, in a case where a voltage is
applied to the transparent-scattering changing element 40, the
liquid crystal molecules are aligned in a vertical direction of the
transparent substrates 41, 42. Thus, the refractive index of the
liquid crystal 45 becomes equal to the ordinary light refractive
index and becomes the same as the refractive index of the polymer
46, so that the polymer dispersed liquid crystal and the polymer
network liquid crystal come to be in a transparent state. When a
voltage is applied and the transparent-scattering changing element
40 comes to be in an electrically transparent state, the image
display device 1 turns to a narrow vision display. In the meantime,
when no voltage is applied and the transparent-scattering changing
element 40 comes to be in an electrically scattering state, the
image display device 1 turns to a wide vision display.
[0053] Between a terminal for supplying a voltage to the
transparent-scattering changing element 40 and a power supply, the
electric current detection element (operation state detection
element) 70A (see FIG. 6) for detecting an electric current flown
to the transparent-scattering changing element 40 is inserted and
connected. Specifically, a resistor is inserted to the terminal of
the transparent-scattering changing element 40, and the electric
current detection element 70A measures the electric current flown
to the transparent-scattering changing element 40 via the resistor
to detect whether or not there is a fault generated in the
transparent-scattering changing element 40.
[0054] The transparent heater 50 is a heating member for heating
the viewing angle changing element 20, which includes a function of
changing the refractive index of the liquid crystal 45 that
constitutes the transparent-scattering changing element 40 to be in
a transparent state so that the image display device 1 comes to be
in a viewing angle display through heating the viewing angle
changing element 20 by supplying an electric power to the
transparent heater 50 from a power supply circuit. The transparent
heater 50 is formed by including: a pair of transparent substrates
51 and 52; a transparent electrode 53 formed at least on one of the
transparent substrates (the transparent substrate 51 in this
embodiment); and an insulating layer 54 provided between the
transparent electrode 53 and the transparent substrate 52. The
transparent electrode 53 is used as a resistor of the heater, and
it is so patterned that a line width is narrow and the distance
between the electrode terminals becomes long as much as possible in
order to increase the resistance value thereof. The transparent
heater 50 generates heat through having an electric current flown
to the transparent electrode 53 from a power supply source via a
pair of electrode terminals. A forcible heating mechanism (a narrow
vision forcible setting module) is formed with the transparent
heater 50 and the power supply circuit, however, the transparent
heater alone will be referred to as a forcible heating mechanism
(the narrow vision forcible setting module) hereinafter. For
example, as the transparent electrode 53, indium tin oxide (ITO),
tin oxide (SnO.sub.2 film), or the like can be used. Further, in
order to increase the resistance value of the transparent electrode
53, the transparent electrode 53 may be formed into a thin film or
may increase the content oxygen.
[0055] Now, the temperature dependency of the
transparent-scattering changing element 40 will be described by
referring to FIG. 5.
[0056] FIG. 5 shows a graph of measured transmittance in a normal
direction of the transparent-scattering changing element 40, when
parallel light is radiated to make incident on the
transparent-scattering changing element 40. However, no voltage is
applied to the transparent-scattering changing element 40 at the
time of measurement. Further, dotted lines in the drawing show the
transmittance of a case where a voltage is applied to the
transparent-scattering changing element 40, which is in a
transparent state (transmission state).
[0057] In a state where the transparent-scattering changing element
40 is not heated and is in a normal temperature (a state where the
temperature on the left side in the drawing is low), the
transmittance is low. As described above, no voltage is applied to
the transparent-scattering changing element 40, so that there is a
difference generated between the refractive index of the liquid
crystal 45 and that of the polymers 46 existing in the surroundings
of the liquid crystal within the transparent-scattering changing
element 40 (the refractive index of the liquid crystal 45 is higher
than the ordinary light refractive index). Because of the
difference in the diffractive indexes, the transparent-scattering
changing element 40 comes to be in a scattering state. Due to the
influence thereof, the proportion of light transmitted into the
normal direction of the transparent-scattering changing element 40
becomes small.
[0058] When the transparent-scattering changing element 40 is
heated and the temperature becomes increased, the transmittance of
the transparent-scattering changing element 40 is increased
drastically in the temperature change of is as shown in FIG. 5. The
transmittance approaches to the transmittance (dotted line of the
drawing) of a case where the transparent-scattering changing
element 40 is in a transparent state. This is because the ordinary
light refractive index of the liquid crystal is increased and the
extraordinary light refractive index is decreased in accordance
with the increase in the temperature of the liquid crystal within
the transparent-scattering changing element 40, so that the
difference between the refractive index of the liquid crystal layer
and the refractive index of the polymers existing in the
surroundings of the liquid crystal layer becomes small and the
transmittance is increased. As described, the
transparent-scattering changing element 40 of the above-described
exemplary embodiment is capable of changing to a transparent state
without applying a voltage by increasing the temperature from the
outside.
[0059] While the transparent heater 50 is disposed on the upper
side of the transparent-scattering changing element 40 (FIG. 1) in
the first exemplary embodiment, it may be disposed under the
transparent-scattering changing element 40 as long as it is
possible to increase the temperature of the transparent-scattering
changing element 40. Further, a transparent electrode heater may be
directly formed on the base member of the transparent-scattering
changing element 40.
[0060] As the above-described non-luminous type display element 60,
it is possible to use a liquid crystal panel which employs a
driving system of a transverse electric field system, a
multi-domain system, a twisted nematic system, and the like. In all
of the cases of those liquid crystal display panels, one pixel
constituting the display screen is formed by a color filter 65
shown in FIG. 1, a thin film transistor (not shown), a common
electrode (not shown), and a pixel electrode (not shown), and a
liquid crystal layer 64 shown in FIG. 1 is interposed between the
common electrode and the pixel electrode. Further, as shown in FIG.
1, a transparent substrate (TFT substrate) 63 is provided on the
outer side (lower side in the drawing) of the liquid crystal layer
64, a retardation plate 62 is provided on the outer side of the
transparent substrate 63, and a polarization plate 61 is provided
on the outer side of the retardation plate 62, respectively. A
transparent substrate (TFT substrate) 66 is provided on the outer
side (upper side in the drawing) of the color filter 65, a
retardation plate 67 is provided on the outer side of the
transparent substrate 66, and a polarization plate 68 is provided
on the outer side of the retardation plate 67, respectively.
[0061] Subsequently, FIG. 6 shows a drive control system of the
image display device 1 according to the first exemplary embodiment
of the present invention.
[0062] Operations of the image display device 1 are controlled by a
control module (e.g., CPU) 17. To the control module 17, connected
are: a power supply switch 16 for setting on/off the operation of
the image display device 1; the backlight 10 which illuminates the
display element (liquid crystal panel) 60 according to "on" of the
power supply switch 16; a viewing angle changing element 20 which
changes the viewing angle display of the display element 60; a
forcible heating mechanism (narrow vision forcible setting module)
50 which forcibly changes the display of images outputted from the
display element 60 to a narrow vision display by heating the
viewing angle changing element 20; and a fault judging module 75
which makes judgments regarding faults in the viewing angle
changing element 20 based on the electric current value flown in
the transparent-scattering changing element 40 of the viewing angle
changing element 20 detected by the electric current detection
element 70A.
[0063] When the power of the image display device 1 is turned on by
an "on"-operation of the power supply switch 16, control of the
control module 17 is started and the display element (liquid
crystal panel) 60 is illuminated by the backlight 10. For example,
in a case of ATM (electronic apparatus) placed at a bank, a
convenience store, or the like, the period including the startup of
the power where no users is using it is so set that the image
outputted from the display element 60 of the image display device 1
is in a wide vision display state by the control of the control
module 17 so as to be able to provide information such as
advertisements to a great number of customers existing in the
surroundings.
[0064] At this time, no voltage is applied to the voltage applying
electrodes 43, 44 of the viewing angle changing element 20, so that
the transparent-scattering changing element 40 is set to be in a
scattering state. When the user approaches to an ATM 98, a sensor
(not shown) detects the approach. The detection signal thereof is
sent to the control module 17, and the image outputted from the
display element 60 of the image display device 1 is set to be in a
narrow vision display state by the control of the control module
17. At this time, a voltage is applied to the voltage applying
electrodes 43, 44 of the viewing angle changing element 20, so that
the transparent-scattering changing element 40 is set to be in a
transparent state.
[0065] The electric current flown to the transparent-scattering
changing element 40 of the viewing angle changing element 20 is
detected by the electric current detection element 70A, and the
detected electric current is sent to the fault judging module 75.
The electric current values (electric current values under a normal
operation) flown into the transparent-scattering changing element
40 at the time of the wide vision display and the narrow vision
display are stored in advance in the fault judging module 75. The
fault judging module 75 compares the electric current value
detected by the electric current detection element 70A with the
stored electric current values to judge an occurrence of a fault in
the viewing angle changing element 20. The result of the judgment
is transmitted to the control module 17. When the judgment result
indicates that there is a fault, the control module 17 starts the
operation of the forcible heating module 50 to heat the viewing
angle changing element 20 so as to forcibly change the display of
the image outputted from the display element 60 to a narrow vision
display.
[0066] Next, a viewing angle changing processing operation of the
image display device 1 will be described.
[0067] First, as shown in a flowchart of FIG. 7, the electric
current flown to the transparent-scattering changing element 40
provided to the viewing angle changing element 20 is monitored,
detected, and measured by the electric current detection element
(operation state detection element) 70A (step S101).
[0068] The drive current value for the viewing angle changing
element 20 detected by the electric current detection element 70A
is sent to the fault judging module 75. The fault judging module 75
compares the electric current value detected by the electric
current detection element 70A with the premeasured and prestored
electric current values that are the values when the
transparent-scattering changing element 40 is not having a fault
but operating normally (step S102).
[0069] Then, the fault judging module 75 judges whether or not
there is a fault generated in the viewing angle changing element 20
based on the comparison result (step S103). Specifically, in a case
where the difference between the detected electric current value
and the prestored electric current values under a normal operation
is within a prescribed range specified in advance (e.g., within
.+-.10% of the normal operation electric current value), it is
judged that there is no fault being generated in the viewing angle
changing element 20. When the difference is out of the prescribed
range, it is judged that there is a fault being generated (fault
state).
[0070] When it is judged as a result that the viewing angle
changing element 20 is having no fault, the processing operation is
ended. In the meantime, when the viewing angle changing element 20
is having a fault (in a case of a fault state), the display on the
display element 60 is forcibly changed to the narrow vision display
by the changing module (narrow vision forcible setting module 50
(step S104). In a case where the transparent-scattering changing
element 40 is electrically changed to a scattering state and the
image display device 1 is set to a state of the wide vision display
because of the fault of the viewing angle changing element 20, a
risk of having the information (a secret code number of the user)
displayed on the screen of the image display device 1 leaked to
other users in the surroundings becomes increased. Thus, the
display of the image outputted from the display element 60 is
forcibly set to the narrow vision display state to prevent the
leakage of the information of the user through changing the
transparent-scattering changing element 40 to a transparent state
by heating the transparent-scattering changing element 40 by the
forcible heating mechanism (transparent heater) 50.
[0071] Further, the above-described viewing angle changing
processing operation of the image display device 1 will be
described in more details by using FIG. 2-FIG. 4. FIG. 2A shows a
narrow vision display operation of the image display device 1.
Arrows in the drawing show spread of light emitted from each of the
structural members 10, 30, 40, 50, and 60 disclosed in FIG. 1.
[0072] First, light 19a emitted from the backlight 10 makes
incident on the micro louver 30 of the viewing angle changing
element 20. The light made incident within the micro louver 30
cannot pass through except for the light within an angle range of
an aspect ratio (a ratio of transparent layer height H30 to
transparent layer width W30 (H30/W30)) of the transparent layer 31
as shown in FIG. 3, and the light spread to the out of the angle
range is absorbed by the light shielding layer 32 that is adjacent
to the transparent layer 31. Thereby, light 39a emitted by
transmitting through the micro louver 30 comes to have a higher
directivity than the light 19a emitted from the backlight 10. The
light 39a emitted from the micro louver 30 makes incident on the
transparent-scattering changing element 40.
[0073] Note here that when a voltage is applied between the
transparent electrodes 43 and 44 of the transparent-scattering
changing element 40, the liquid crystal 45 sandwiched between the
both transparent electrodes 43 and 44 is aligned to the electric
field direction. The refractive index of the liquid crystal 45
becomes matched with the refractive index of the polymers 46
existing in the surroundings thereof due to the change in the
alignment, so that the transparent-scattering changing element 40
is turned to a transparent state. The light made incident on the
transparent-scattering changing element 40 transmits therethrough
while keeping the directivity of the light 39a emitted from the
micro louver 30, and makes incident on the transparent heater
50.
[0074] The heater 50 does not exhibit the scattering property of
such an extent to change the directivity of incident light 49a
greatly and transmits the light 49a, so that the light 49a emitted
from the viewing angle changing element 20 makes incident on the
display element 60 while keeping the directivity. Further, the
display element 60 also keeps the directivity as the case of the
transparent heater 50, so that light 69a from the display element
60 is emitted by keeping the distribution of the light emitted from
the viewing angle changing element 20. Thus, the image display
device 1 as a whole is set to a narrow vision display state.
[0075] Subsequently, FIG. 2B shows a wide vision display operation
of the image display device 1. Arrows in the drawing show spread of
light emitted from each of the structural members 10, 30, 40, 50,
and 60 as in the case of FIG. 2A described above.
[0076] As in FIG. 2A described above, the light 19a emitted from
the backlight 10 becomes the light 39a with a wide directivity at a
stage where it passes through the micro louver 30 of the viewing
angle changing element 20, and makes incident on the
transparent-scattering changing element 40.
[0077] When no voltage is applied between the transparent
electrodes 43 and 44 of the transparent-scattering changing element
40, the liquid crystal molecules sandwiched between the both
transparent electrodes 43 and 44 stay in a random alignment.
Thereby, there is a difference generated between the refractive
index of the liquid crystal 45 and that of the polymers 46, so that
the transparent-scattering changing element 40 turns to a
scattering state. Thus, the light 39a making incident on the
transparent-scattering changing element 40 is scattered when
passing through the transparent-scattering changing element 40.
Therefore, the directivity of light 49b emitted from the
transparent-scattering changing element 40 becomes narrower than
that of the incident light 39a.
[0078] The light 49b emitted from the transparent-scattering
changing element 40 makes incident on the transparent heater 50.
The transparent heater 50 does not exhibit the scattering property
of such an extent to change the directivity of incident light 49b
greatly and transmits the light 49b. Thus, light 59a emitted from
the transparent heater 50 makes incident on the display element 60
while keeping the directivity of the light 49b emitted from the
transparent-scattering changing element 40 of the viewing angle
changing element 20. Further, the display element 60 also keeps the
directivity as in the case of the transparent heater 50, so that
light 69a from the display element 60 is emitted by keeping the
distribution of the light emitted from the transparent-scattering
changing element 40. Thus, the image display device 1 as a whole is
set to a wide vision display state.
[0079] As described, the viewing angle changing operation of the
image display device 1 can be achieved by electrically changing the
transparent-scattering changing element 40 to a transparent state
and a scattering state. Thus, a fault in changing the viewing angle
of the image display device 1 means a fault generated in the
transparent-scattering changing element 40. A specific problem in
the fault in changing the viewing angle is a case where the image
display device 1 accidentally turns to the wide vision display when
it is desired to be used as the narrow vision display.
[0080] The fault in the viewing angle changing operation of the
image display device 1, i.e., the fault in the
transparent-scattering changing element 40, is specifically
classified into four fault modes as shown in a table of FIG. 4.
[0081] Fault mode 1 is an abnormal voltage fault mode of a case
where a voltage of equal to or less than a threshold voltage of the
transparent-scattering changing element 40 is applied between the
transparent electrodes 43 and 44.
[0082] Fault mode 2 is an open fault mode of a case where the
electrode terminal connected to the transparent-scattering changing
element 40 is in a state (open state) of being incapable of
electrically connected to the transparent electrodes 43, 44 of the
transparent-scattering changing element 40, so that the voltage
cannot be supplied to the transparent-scattering changing element
40.
[0083] Fault mode 3 is a short-circuit fault mode of a case where
the transparent-scattering changing element 40 short-circuits, so
that the voltage cannot be applied between the elements.
[0084] Fault mode 4 is an overvoltage fault mode of a case where an
excessive voltage is applied to the transparent-scattering changing
element 40 because of some reasons.
[0085] In the fault modes 1 to 3 out of the fault modes described
above, a sufficient voltage cannot be applied to the
transparent-scattering changing element 40, so that the element
comes to be in a scattering state. Thus, the image display device 1
is set to a wide vision display state. In the meantime, in the
fault mode 4, the transparent-scattering changing element 40 comes
to be in a transparent state. Thus, the image display device 1 is
set to be in a narrow vision display state.
[0086] Whether or not there is an occurrence of those fault modes 1
to 4 can be judged by detecting the electric current value flown in
the transparent-scattering changing element 40 by the electric
current detection element 70A. In a case of the fault modes 1 and
2, the electric current flown in the transparent-scattering
changing element 40 becomes smaller than the electric current value
required for the narrow vision display, i.e., for setting the image
display device 1 to a transparent state. Particularly, in the fault
mode 2, a voltage cannot be applied to the transparent-scattering
changing element 40, so that the electric current is not flown into
the transparent-scattering changing element 40. Thus, the electric
current value of the fault mode 2 is smaller than that of the fault
mode 1.
[0087] In the case of the fault modes 3 and 4, the electric current
flown in the transparent-scattering changing element 40 becomes
greater than the electric current value required for the wide
vision display, i.e., for setting the image display device 1 to a
transparent state (narrow vision display). Particularly, in the
fault mode 3, an excessive electric current is flown in the
transparent-scattering changing element 40 because of short-circuit
generated in the transparent scattering changing element 40.
[0088] That is, as is clear in the above-described related
techniques, no measure is taken for the fault generated in the
viewing angle changing element 20 of the conventionally known
related techniques. Thus, it is only a way to actually check the
display screen for detecting whether or not there is a fault.
Therefore, displayed information may become leaked until checking
of the screen can be done. However, through monitoring the electric
current value flown in the transparent-scattering changing element
40 by using the detection element as in the first exemplary
embodiment described above, it is possible to detect a fault
generated in the viewing angle changing element 20 without checking
the display screen.
(Entire Operation)
[0089] Next, the entire operation of the image display device 1 at
the time of having a fault will be described.
[0090] The image display device 1 detects the electric current
value flown in the viewing angle changing element 20, i.e., the
electric current value flown in the transparent-scattering changing
element 40, by using the electric current detection element 70A
(see FIG. 6). It is sufficient to execute the detection processing
only when a user is using the device 1, if it is only for the
purpose of preventing leakage of secret information (e.g., secret
code numbers) of the user. However, it is desirable to execute the
detection processing periodically at every prescribed time interval
set in advance, considering the cases of abnormal state where the
overvoltage is applied between the elements, for example. The image
display device 1 in that case stores desired electric current
values flown to the transparent-scattering changing element 40 in
the wide vision display and the narrow vision display under a
normal operation in the storage section of the fault judging module
75 provided within the image display device 1 in advance as the
reference electric current values.
[0091] The fault judging module 75 of the image display device 1
compares the stored reference electric current values of each
display state with the detected (actually measured) electric
current value to judge whether or not there is a fault generated in
the transparent-scattering changing element 40, i.e., the viewing
angle changing element 20. Specifically, first, judged is whether
or not it is in a state used by the user. Then, when judged that is
a state being used by the user, the fault judging module 75 reads
out the stored reference electric current value of the narrow
vision display, and compares the reference electric current value
with the detected electric current value.
[0092] When the difference between the detected electric current
value and the reference electric current value is judged as being
within a prescribed range (e.g., .+-.10% of the reference electric
current values) as a result of the comparison, it is judged that
there is no fault generated in the viewing angles changing element
20. When the difference is out of the prescribed range, it is
judged that there is a fault. The above-described modes 1 and 2
correspond to a case where the detected electric current value is
small and out of the prescribed range. In the meantime, the
above-described fault modes 3 and 4 correspond to a case where the
detected electric current value is large and out of the prescribed
range.
[0093] Further, when it is found in the judgment that the device is
not being used, the fault judging module 75 reads out the stored
reference electric current value of the wide vision display and
compares the reference electric current value with the detected
electric current value. When the difference between the detected
electric current value and the reference electric current value is
found to be within the prescribed range as a result of the
comparison, it is judged that there is no fault generated in the
viewing angle changing element 20. When the difference is out of
the prescribed range, it is judged that there is a fault.
[0094] In a case of the wide vision display under a normal
operation, no voltage is applied between the transparent electrodes
43 and 44 of the transparent-scattering changing element 40. Thus,
no electric current flows in the transparent scattering changing
element 40. Therefore, the fault mode 1, 3, or 4 corresponds to a
case where the detected electric current value is out of the
prescribed range, i.e., a case where the detected electric current
value is large and out of the prescribed range. Further, in the
case of the fault mode 3 or 4, the detected electric current value
becomes larger than the stored reference electric current value of
the narrow vision display. Thus, it is possible to discriminate
whether it is an occurrence of the fault mode 3 or an occurrence of
the fault mode 4 through comparing the detected electric current
value with the reference electric current value.
[0095] In a case where it is judged as a result of the comparison
and judgment that the transparent-scattering changing element 40 is
having a fault, the image display device 1 first stops the supply
of the voltage to the transparent-scattering changing element 40.
Then, the transparent heater (the forcible heating mechanism) 50 as
a changing module is operated to heat the transparent-scattering
changing element 40. This makes it possible to detect an occurrence
of a fault instantly even when there is a fault generated in the
transparent-scattering changing element 40. Thus, the
transparent-scattering changing element 40 is heated and turned
into a transparent state, so that the image display device 1 is
forcibly set to a narrow vision display. Thereby, leakage of the
information on the display can be prevented.
[0096] In the fault mode 4, it is unnecessary to heat the
transparent-scattering changing element 40 by the transparent
heater if it is solely for preventing leakage of the information of
the user since the transparent-scattering changing element 40 is
being turned into the transparent state. However, it is in an
abnormal state where the overvoltage is applied between the
elements, so that the supply of the voltage to the
transparent-scattering changing element 40 may be stopped and the
transparent-scattering changing element 450 may be heated as in the
case of the other fault modes 1 to 3 for the security. It is
possible to keep the security by avoiding the overvoltage through
stopping supply of the voltage and to set the image display device
to a narrow vision display by heating.
[0097] While a PLNC (Polymer Network Liquid Crystal) element that
comes into a scattering state when no voltage is applied between
the transparent electrodes 43, 44 is used as the
transparent-scattering changing element 40 of the image display
device 1, the transparent-scattering changing element 40 is not
limited only to that. For example, a reverse PNLC element which
comes to be in a transparent state under a voltage-unapplied state
may be used. In that case, the transparent state and the scattering
state in the voltage applied state and the unapplied state of the
transparent-scattering changing element 40 are reversed. Therefore,
the relation between the fault state of the transparent-scattering
changing element 40 and the operation of the transparent heater
(forcible heating mechanism) 50 is inverted.
[0098] That is, in a case where the reverse PNLC element is used,
the transparent-scattering changing element 40 comes to be in a
scattering state only in the fault mode 4 where the overvoltage is
applied out of the above-described fault modes. Thus, it is
necessary to change the transparent-scattering changing element 40
to a transparent state by forcibly operating the transparent heater
(forcible heating mechanism) 50 as the changing module.
[0099] In the meantime, in the cases of the other fault modes 1 to
3, the transparent-scattering changing element 40 is in a
transparent state. Thus, it is unnecessary to forcibly heat the
element 40 by operating the transparent heater 50. However, the
voltage supply to the transparent-scattering changing element 40
cannot be done because of the fault in all of the cases of the
fault modes 1 to 3, so that it is also possible to forcibly change
to the narrow vision display through heating the element 40 by the
transparent heater 50.
[0100] As an exemplary advantage according to the invention, the
invention makes it possible to detect a fault instantly, even when
the fault in changing the viewing angles occur in the image display
device capable of changing the viewing angle and in the electronic
apparatus using the same. Further, the image display device can be
forcibly changed into the narrow vision display based on the
detection, so that it is possible to prevent leakage of information
displayed on the display screen.
Second Exemplary Embodiment
[0101] Next, a second exemplary embodiment of the image display
device according to the present invention will be described by
referring to FIG. 8-FIG. 11. Note here that same reference numerals
are applied to the same structural members as those of the first
exemplary embodiment described above.
[0102] As shown in FIG. 8, an image display device 2 is formed by
including: a backlight 10; a viewing angle changing element 20A
provided on the upper side of the backlight 10 for electrically
changing the viewing angle range; and a non-luminance type display
element 60 provided on the upper side of the viewing angle changing
element 20A. Note that the members under the same reference
numerals as those of the image display device 1 of the first
exemplary embodiment shown in FIG. 1 have the same functions.
Further, while not shown in FIG. 8, the image display device 2 is
also provided with an electric current detection element (operation
state detection element) 70A (see FIG. 9 and FIG. 10) which
monitors the state of the viewing angle changing element 20A and a
fault judging module 75 (see FIG. 10) which judges whether or not
the viewing angle changing element 20A is having a fault based on
the measurement value detected by the electric current detection
element 70A.
[0103] The difference between the second exemplary embodiment and
the first exemplary embodiment is that a transparent-scattering
changing element 40A of the viewing angle changing element 20A is
provided with transparent electrodes 48a and 48b used at the time
of having a fault (voltage applying electrodes used exclusively
when there is a fault) as a narrow vision forcible setting module
(changing module 50) for forcibly changing the viewing angle range
to the narrow vision display at the time of having a fault. In the
second exemplary embodiment, the transparent heater 50 (the
changing module of the first exemplary embodiment) for heating the
viewing angle changing element 20A is not provided.
[0104] FIG. 9 shows an example of the transparent-scattering
changing element 40A of the second exemplary embodiment. The
transparent electrodes 48a, 48b are electrodes loaded in addition
to the transparent electrodes 43, 44 that are used under a normal
operation. The transparent electrodes 48a, 48b are covered by
insulating layers 47a, 47b, and insulated from the transparent
electrodes 43, 44. Further, while a power supply source 36 is
connected to the transparent electrodes 48a, 48b used at the time
of having a fault, the connection between both transparent
electrodes are electrically opened by a switch 35 or the like
except for the time of having a fault generated in the viewing
angle changing element 20A. A changing control module 37 for
changing on/off of the switch is connected to the switch 35. The
changing control module 37 operates based on changing control
signals from the control module 17 (see FIG. 10).
[0105] The electric current detection element 70A which monitors
the state of the viewing angle changing element 20A is interposed
between the terminal connected to the transparent electrodes 43, 44
used under a normal operation and the power supply source 34.
Further, a voltage-application changing switch 95 for changing
whether or not to apply a voltage between the transparent
electrodes 43, 44 is connected between the electric current
detection element 70A and the power supply source 34. The
voltage-application changing switch 95 operates based on drive
control signals from a switch drive control section 96, and the
switch drive control section 96 operates based on changing command
signals from a changing command input section 97.
[0106] For example, in FIG. 9, when a user approaches to an ATM
(electronic apparatus) in a bank or a convenience store, a sensor
as the changing command input section 97 detects the approach of
the user, and a changing command signal based on the detection is
sent to the switch drive control section 96 from the changing
command input section 97. The switch drive control section 96
transmits a drive control signal for changing the
voltage-application changing switch 95 to the voltage-application
changing switch 95 based on the received changing command signal.
Upon receiving this signal, the voltage-application changing switch
95 is turned on, and a voltage is applied between the transparent
electrodes 43, 44. Thereby, the transparent-scattering changing
element 40A comes to be in a transparent state electrically, and
the image display device 2 is changed to a narrow vision display
state so that the personal information of the user displayed on the
display screen is not leaked to those in the surroundings. However,
the changing operation of the voltage-application changing switch
95 may be done manually without providing the switch drive control
section 96 and the changing command input section 97.
[0107] FIG. 10 shows a drive control system of the image display
device 2 according to the second exemplary embodiment.
[0108] The operation of the image display device 2 is controlled by
the control module (e.g., CPU) 17, for example. Note here that the
power supply switch 16, the backlight 10, the display element 60,
the viewing angle changing element 20A, the transparent-scattering
changing element 40A, the electric current detection element 70A,
and the fault judging module 75 have the same functions as the
respective members under the same reference numerals of the image
display device 1 described in the first exemplary embodiment.
[0109] The difference with respect to the drive control system of
the first exemplary embodiment is that the viewing angle changing
element 20A of the drive control system according to the second
exemplary embodiment is provided with the fault-state voltage
applying electrodes 48a and 48b which are used when there is a
fault generated in the transparent-scattering changing element
40A.
[0110] Illuminating the display element 60 under controls of the
control module 17 at the rise of the power upon an on-operation of
the power supply switch 16, setting of the wide vision display
state when the device is not being used, setting of the narrow
vision display when the device is being used, etc., are same as the
control processing contents described in the first exemplary
embodiment. Further, detection of the electric current executed by
the electric current detection element 70A, judgment of a fault
executed by the fault judging module 75, etc., are also same as the
processing contents described in the first exemplary embodiment.
Unlike the controls of the first exemplary embodiment, when it is
judged as a result of the fault judgment executed in the second
exemplary embodiment that there is a fault being generated, the
control module 17 is designed to execute a control to forcibly
change the display of the image outputted from the display element
60 of the image display device 2 to a narrow vision display state
by stopping supply of the voltage to the transparent electrodes 43,
44 used under a normal operation and by applying a voltage to the
transparent electrodes 48a, 48b (voltage applying electrodes used
exclusively when there is a fault) used at the time of having a
fault. Through applying a voltage to the voltage applying
electrodes 48a, 48b used exclusively for the time of having a
fault, the transparent-scattering changing element 40A is turned to
a transparent state electrically. Thereby, the image display device
2 is set to a narrow view field display.
[0111] Next, the viewing angle changing processing operation of the
image display device 2 will be described. The flowchart of FIG. 11
shows the viewing angle changing processing operation of the image
display device 2. Contents of each of the processing operations of
steps S201 to S203 are the same as the contents of each of the
processing operations of steps S101 to S103 of the viewing angle
changing processing operation (the flowchart shown in FIG. 7) of
the image display device 1 according to the first exemplary
embodiment described above. Further, an operation executed in step
S204 for forcibly changing the display of the display element 60 to
a narrow vision display when the viewing angle changing element 20A
is having a fault is the same as that of the first exemplary
embodiment (the operation of step S104 of the flowchart shown in
FIG. 7).
[0112] However, the viewing angle changing processing of the image
display device 2 is different from that of the first exemplary
embodiment (forcible heating mechanism (transparent heater)) in
respect that a voltage forcible applying mechanism is provided as a
narrow vision forcible setting module 50 for forcibly changing the
narrow vision display in step S204. For example, as the voltage
forcible applying mechanism, the image display device 2 is further
provided with the voltage applying electrodes 48a, 48b used
exclusively when there is a fault, in addition to the voltage
applying electrodes 43, 44 used under a normal state where no fault
is generated. The voltage applying electrodes 48a and 48b are
provided by sandwiching the liquid crystal layer 45, and a voltage
is applied thereto when there is a fault. Thereby, the voltage
applying electrodes 48a and 48b give a voltage difference to the
transparent-scattering changing element 40A to turn the
transparent-scattering changing element 40A to a transparent state,
and to forcibly set the display of the image outputted from the
display element 60 to a narrow vision display so as to prevent
leakage of the information of the user.
[0113] Further, the operation of the image display device 2 at the
time of having a fault will be described in more details.
[0114] A fault generated in the viewing angle changing function is
based on a fault generated in the transparent-scattering changing
element 40A as in the case of the image display device 1 according
to the first exemplary embodiment described above. Further, the
fault modes 1-4 are the same as the case of the first exemplary
embodiment.
[0115] The image display device 2 detects the electric current
value flowing in the viewing angle changing element 20A, i.e., the
electric current value flowing in the transparent-scattering
changing element 40A, by using the electric current detection
element (operation state detection element) 70A which is connected
to the transparent electrodes 43, 44 used for a normal operation.
At this time, the image display device 2 stores in advance desired
electric current values of a wide vision display and a narrow
vision display flowing in the transparent-scattering changing
element 40A in the storage section of the fault judging module 75
provided within the image display device 2.
[0116] The image display device 2 compares the stored electric
current values of each display state with the detected electric
current value, and judges whether or not the transparent-scattering
changing element 40A, i.e., the viewing angle changing element 20A,
is having a fault. The detailed contents of comparison/judgment are
the same as those of the first exemplary embodiment. In a case
where it is judged as a result of the comparison and judgment that
the transparent-scattering changing element 40A is having a fault,
the image display device 2 first stops the supply of the voltage to
the transparent-scattering changing element 40A, i.e., stops the
supply of the voltage to the transparent electrodes 43, 44 used for
a normal operation. Then, the transparent electrodes 48a, 48b
provided for the case of having a fault (voltage forcible applying
mechanism used exclusively when there is a fault) are operated to
be used as a drive source of the transparent-scattering changing
element 40A.
[0117] This makes it possible to drive the transparent-scattering
changing element 40A by adding a potential difference to the liquid
crystal layer 45 through applying a voltage between the transparent
electrodes 48a and 48b, even when there is a fault generated in the
viewing angle changing element 20A. Thus, the
transparent-scattering changing element 40 to which the voltage is
applied turns into a transparent state electrically, so that the
image display device 2 is forcibly set to a narrow vision display
state. Thereby, leakage of the information on the display screen
can be prevented, even when there is a fault generated in the
viewing angle changing element 20A.
[0118] In this exemplary embodiment, insulating layers 47a, 47b and
the transparent electrodes 48a, 48b are interposed between the
transparent electrodes 43 and 44 used for a normal drive, in
addition to the transparent-scattering changing layer. Thus, the
potential difference applied to the transparent-scattering changing
layer becomes smaller than the case where there is only the
transparent-scattering changing layer provided between the
transparent electrodes 43 and 44. Therefore, in order to compensate
for the drop in the voltage difference, a voltage that is a sum
voltage of the potential difference required for the
transparent-scattering changing layer and the potential drop
generated because the insulating layers 47a, 47b and the
transparent electrodes 48a, 48b are interposed is applied between
the transparent electrodes 43 and 44 for driving. Further, the
voltage drop is added to the stored electric current values that
are compared and referred with respect to the electric current
values detected by the electric current detection element 70A.
[0119] Other structures and operation effects thereof are the same
as those of the case of the first exemplary embodiment described
above.
Third Exemplary Embodiment
[0120] Next, a third exemplary embodiment of the image display
device according to the present invention will be described by
referring to FIG. 12.
[0121] The image display device according to the third exemplary
embodiment is formed by including a backlight 10 and a display
element 60 as in the case of the image display device 2 according
to the second exemplary embodiment shown in FIG. 8. However, in a
transparent-scattering changing element 40B constituting a viewing
angle changing element 20B of the image display device according to
the third exemplary embodiment, only a pair of transparent
electrodes 43 and 44 are provided by sandwiching a liquid crystal
layer 45 as shown in FIG. 12. Further, on the same side of the
transparent electrodes 43 and 44, not only electrode terminals 21A,
21B used under a normal operation but also electrode terminals 22A,
22B used at the time of having a fault are provided on the same
side of the transparent-scattering changing element 40B where the
electrode terminals 21A, 21B are provided. In this respect, the
transparent-scattering changing element 40B is greatly different
from the transparent-scattering changing element 40A of the second
exemplary embodiment which does not have such structure.
[0122] The backlight 10, a micro louver 30, and the display element
60 have the same functions and exhibit same operational effects as
those of the second exemplary embodiment. Further, as in the case
of the second exemplary embodiment, the image display device
according to the third exemplary embodiment includes: an electric
current detection element 70A which monitors the state of the
viewing angle changing element 20B; and a fault judging module 75
which judges an occurrence of a fault generated in the viewing
angle changing element 20B (the transparent-scattering changing
element 40B) based on the measurement value from the detection
element.
[0123] FIG. 12A is a fragmentary plan view showing the
transparent-scattering changing element 40B of the image display
device according to the third exemplary embodiment. FIG. 12B is a
perspective view of the transparent-scattering changing element 40B
of the image display device according to the third exemplary
embodiment. Note, however, that transparent substrates 41, 42
provided on the outside of the transparent electrodes 43, 44 are
not illustrated in FIG. 12A and FIG. 12B.
[0124] The image display device according to the third exemplary
embodiment includes the electrode terminals (voltage forcibly
applying mechanism) 22A and 22B used at the time of having a fault
as a means for forcibly changing the viewing angle range to a
narrow vision display when there is a fault generated in the
transparent-scattering changing element 40B. The electrode
terminals 22A, 22B are provided to the transparent electrodes 43,
44 used under a normal operation, and are provided separately from
the electrode terminals 21A, 21B which are provided for applying a
voltage to the transparent electrodes 43, 44 at the time of a
normal operation. Further, the electrode terminals 22A, 22B are
provided on the same side of the transparent electrodes 43, 44
where the electrode terminals 21A, 21B used under a normal
operation are provided. That is, the electrode terminals 22A, 22B
are provided on the same side of the transparent-scattering
changing element 40B along with the electrode terminals 21A,
21B.
[0125] The electrode terminals 22A, 22B used at the time of having
a fault are connected to a power supply source 36. However, those
are in an electrically open state by a switch 35 or the like
according to a changing control signal from a changing control
module 37 except for a case where there is a fault being generated.
When it is judged by the fault judging module 75 that there is a
fault generated in the transparent-scattering changing element 40B,
the changing control module 37 turns on the switch 35 according to
the judgment signal so that a voltage is applied to the electrode
terminals 22A, 22B used at the time of having a fault. Further, the
electric current detection element (operation state detection
element) 70A which monitors the state of the viewing angle changing
element 20B is inserted between the power supply source 34 and the
electrode terminals 21A and 21B used under a normal operation.
[0126] Through having such structure, the image display device
according to the third exemplary embodiment is capable of securely
detecting that there is a fault generated in the
transparent-scattering changing element 40B, and capable of
operating the transparent-scattering changing element 40B when
there is a fault by applying a voltage via the electrode terminals
22A, 22B used at the time of having a fault. Therefore, the
transparent-scattering changing element 40B is electrically turned
to a transparent state when there is a fault, and the image display
device is forcibly set to a narrow vision display state. This makes
it possible to prevent leakage of the information displayed on the
display screen, even when there is a fault. Further, the third
exemplary embodiment does not have a layer for decreasing the
potential difference applied to the transparent-scattering changing
element 40B, such as the insulating layers 47a, 47b and the
transparent electrodes 48a, 48b of the second exemplary embodiment
shown in FIG. 9, between the transparent electrodes 48a and 48b
used for a normal drive. Therefore, it is unnecessary to increase
the potential difference applied between the transparent electrodes
43 and 44 by taking the voltage drop into consideration. In
addition, it is possible to compactify the size of the
transparent-scattering changing element 40B.
[0127] Other structures and operation effects thereof are the same
as those of the case of the second exemplary embodiment described
above.
Fourth Exemplary Embodiment
[0128] Next, a fourth exemplary embodiment of the image display
device according to the present invention will be described by
referring to FIG. 13.
[0129] The image display device according to the fourth exemplary
embodiment is a device in which a part of the structure of the
transparent-scattering changing element 40A is changed among the
image display device 2 (see FIG. 8) according to the second
exemplary embodiment described above. The other members such as a
backlight 10, a micro louver 30, and a display element 60 have the
same functions as those of the second exemplary embodiment.
Further, as in the case of the second embodiment, an electric
current detection element (operation state detection element) 70A
for monitoring the state of a viewing angle changing element 20C
and a fault judging module 75 for judging an occurrence of a fault
generated in the viewing angle changing element 20C based on the
measured value from the detection element are also provided.
[0130] FIG. 13A is a sectional view of a transparent-scattering
changing element 40C which constitutes the image display device of
the fourth exemplary embodiment. Further, FIG. 13B is a perspective
view of the transparent-scattering changing element 40C. Note,
however, that transparent substrates 41, 42 provided on the outside
of transparent electrodes 43, 44 are not illustrated in FIG.
13B.
[0131] In the fourth exemplary embodiment, as shown in FIG. 13, the
transparent electrode 44 is stacked on the lower side of a liquid
crystal layer 45. Further, a transparent electrode 48a is staked on
the upper side of the liquid crystal layer 45, an insulating layer
47a is provided on the upper side thereof, and the transparent
electrode 43 is stacked on the upper side thereof. Therefore, the
transparent-scattering changing element 40C of the fourth exemplary
embodiment is different from the structure of the
transparent-scattering changing element 40A according to the second
exemplary embodiment in respect that the transparent electrode 48b
and the insulating layer 47b are not stacked between the
transparent electrode 44 and the liquid crystal layer 45. A
transparent substrate is stacked on the outer side (on the upper
side and lower side of the drawing) of the transparent electrodes
43 and 44, respectively, although not shown in FIG. 13.
[0132] Further, as shown in FIG. 13B, electrode terminals 24, 25,
and 26 for applying a voltage from a power supply source are
provided to the respective transparent electrodes 43, 44, and 48a.
Furthermore, an electrode terminal 27 for applying a voltage to
operate the transparent electrode 48a as a heater at the time of
having a fault is provided to the transparent electrode 48a on the
same side as the side where the electrode terminal 26 is
provided.
[0133] Further, as shown in FIG. 13A, electric current detection
elements (operation state detection elements) 70A and 70B for
monitoring the operation state of the viewing angle changing
element 20C are provided in the fourth exemplary embodiment. The
electric current detection element 70A is provided between the
electrode terminal 24 of the transparent electrode 43 used under a
normal operation and a power supply source 34, and the electric
current detection element 70B is provided between the electrode
terminal 26 and a power supply source 36. Application of the
voltage between the electrode terminals 25 and 26 is changed by the
switch 35 connected between the power supply source 36 and the
electrode terminal 25, and on/off of the switch is controlled by a
changing control module 37 connected to the switch 35.
[0134] Among the electrode terminals provided to each of the
transparent electrodes 43, 44, and 48a, the electrode terminals 24
and 25 are used as electrode terminals for monitoring the viewing
angle changing element 20C under a normal operation, while the
electrode terminal 26 is used as an electrode terminal for judging
which one of the electrode terminals 24 and 25 has a fault when a
fault is generated. Further, the electric current detection element
70A is used as a detection element for detecting that there is a
fault generated in the electrode terminal 24 or the electrode
terminal 25, while the electric current detection element 70B is
used as a detection element for detecting which one of the
electrode terminals 24 and 25 a fault is generated.
[0135] Next, the operation of the image display device ah the time
of having a fault will be described.
[0136] Under a normal operation of the transparent-scattering
changing element 40C, a voltage is applied between the electrode
terminal 24 and the electrode terminal 25, i.e., between the
transparent electrode 43 and the transparent electrode 44, to give
a potential difference to the transparent-scattering changing
element 40C for driving it. At that time, the potential difference
to be applied between the transparent electrode 43 and the
transparent electrode 44 is determined by adding a voltage drop
generated because of the insulating layer 47a and the transparent
electrode 48a interposed between the transparent electrodes 43 and
44, as in the case of the second exemplary embodiment described
above.
[0137] Then, when there is a fault generated in the electrode
terminal 24 out of the electrode terminals 24 and 25 used normally,
a voltage is applied between the electrode terminal 25 and the
electrode terminal 26 that is provided for the case of having a
fault, i.e., between the transparent electrode 44 and the
transparent electrode 48a, to give a potential difference to the
transparent-scattering changing element 40C for driving it. The
transparent electrode 48a is assumed to be used also as a resistor,
as will be described later. Therefore, the transparent electrode
48a is a patterned electrode, and space between the patterns is
formed extremely narrow. Thus, the transparent electrode 48a can be
used as the electrode for changing transparent and scattering
states while causing almost no deterioration in the
transparent-scattering changing performance.
[0138] Further, when there is a fault generated in the electrode
terminal 25 out of the electrode terminals 24 and 25 used normally,
a voltage is applied between the electrode terminal 26 and the
electrode terminal 27 provided for driving the transparent heater,
i.e., between the two electrode terminals 26 and 27 provided to the
transparent electrode 48a, to supply power. Further, the
transparent electrode 48a is used as the resistor of the
transparent heater to heat the transparent-scattering changing
element 40C.
[0139] As in the case of the transparent electrode 53 shown in the
first exemplary embodiment, the transparent electrode 48a is formed
to be in a narrow line width for increasing the resistance value of
the transparent electrode 48a. At the same time, the transparent
electrode 48a is patterned to provide a long distance between the
electrode terminals, i.e., between the electrode terminal 26 and
the electrode terminal 27, as much as possible. Therefore, it is
possible to generate heat by supplying an electric current to the
transparent electrode 48a via a pair of the electrode terminals 26
and 27 from the power supply source, so that the transparent
electrode 48a can function as a heater. Further, it is also
possible to form the transparent electrode 48a into a thin film or
to increase the oxygen content in order to increase the resistance
value of the transparent electrode 48a.
[0140] Which one of the electrode terminals 24 and 25 is having a
fault can be judged by using the electric current detection element
70B that is connected to the electrode terminal 26. For example, a
voltage is applied between the electrode terminals 24 and 25 used
under a normal operation to drive the transparent-scattering
changing element 40C. When there is a fault generated in the
transparent-scattering changing element 40C, application of the
voltage between the electrode terminals 24 and 25 is stopped. Then,
a voltage is applied between the electrode terminal 25 and the
electrode terminal 26 to drive the transparent-scattering changing
element 40C, the electric current value flown into the
transparent-scattering changing element 40C at that time is
measured by the electric current detection element 70B, and it is
judged by the fault judging module 75 whether or not there is a
fault being generated based on the measured electric current
value.
[0141] When it is found as a result of judgment that there is a
fault, it can be judged that there is a fault generated in the
electrode terminal 25. In the meantime, when it is found as a
result of judgment that there is no fault, it can be judged that
there is a fault generated in the electrode terminal 24. In a case
where there is a fault generated in the electrode terminal 25, the
transparent-scattering changing element 40C is heated in the manner
described above by using the electrode terminal 26 and the
electrode terminal 27. In a case where there is a fault generated
in the electrode terminal 24, the transparent-scattering changing
element 40C is driven by keeping the use of the electrode terminal
25 and the electrode terminal 26.
[0142] Further, while it is described above to drive the
transparent-scattering changing element 40C by applying a voltage
thereto by using the electrode terminal 25 and the electrode
terminal 26 when there is a fault generated in the electrode
terminal 24, it is also possible to heat the transparent-scattering
changing element 40C by utilizing the electrode terminal 26 and the
electrode terminal 27 without using the electrode terminal 25
(without giving a voltage difference to the transparent-scattering
changing element 40C).
[0143] Through the operation processing described above, the
transmittance can be increased by increasing the normal light
refractive index of the liquid crystal to reduce the difference
between the refractive index of the liquid crystal and the
refractive index of the polymer when there is a fault. This makes
it possible to turn the transparent-scattering changing element 40C
to a transparent state and set the image display device 1 to a
narrow vision display state forcibly. Thereby, it is possible to
prevent leakage of the information on the display screen.
[0144] Other structures and operation effects thereof are the same
as those of the case of the second exemplary embodiment described
above.
Fifth Exemplary Embodiment
[0145] Next, a fifth exemplary embodiment of the image display
device according to the present invention will be described by
referring to FIG. 14 and FIG. 15. Note here that same reference
numerals are applied to the same structural members as those of the
first exemplary embodiment described above.
[0146] As shown in FIG. 14, an image display device 3 according to
the fifth exemplary embodiment is formed by including: a backlight
10; a transparent heater 50 having a heating function, which is
provided on the upper side of the backlight 10; a retardation
control liquid crystal cell (viewing angle changing element) 80 for
electrically changing the viewing angle range, which is provided on
the upper side of the transparent heater 50; and a non-luminance
type display element 60 provided on the upper side of the
retardation control liquid crystal cell 80.
[0147] The structure including the backlight 10, the transparent
heater 50, the viewing angle changing element 80, and the display
element 60 is the same as that of the image display device 1 of the
first exemplary embodiment shown in FIG. 1. However, the image
display device 3 according to the fifth exemplary embodiment is
different from the image display device 1 according to the first
exemplary embodiment in respect that the viewing angle changing
element 80 is formed by the retardation control liquid crystal
cell.
[0148] The members under the same reference numerals as those of
the image display device 1 according to the first exemplary
embodiment shown in FIG. 1 have the same functions. While not shown
in FIG. 14, also provided are an electric current detection element
(operation state detection element) 70A (see FIG. 15) for
monitoring the state of the retardation control liquid crystal cell
80 and a fault judging module 75 (see FIG. 15) for judging whether
or not there is a fault generated in the viewing angle changing
element 80 based on the measurement value detected by the electric
current detection element 70A.
[0149] As shown in FIG. 14, the retardation control liquid crystal
cell 80 includes a pair of transparent substrates 83 and 85, and a
liquid crystal 84 aligned homogeneously is sandwiched between those
transparent substrates. The homogeneous alignment is a state of
alignment in which the major axis direction of the liquid crystal
molecule group sandwiched between the transparent substrates 83 and
85 is in parallel to the faces of the transparent substrates 83 and
85. Further, while not shown in FIG. 14, transparent electrodes 88,
89 (see FIG. 15) are loaded to the transparent substrates 83, 85,
respectively. Furthermore, at least retardation plates 82, 86 for
compensating the phase of the liquid crystal and polarization
plates 81, 87 are provided on the outside of the both transparent
substrates 83, 85.
[0150] While the two polarization plates 81, 87 on top and bottom
are used for the retardation control liquid crystal cell 80 in the
form shown in FIG. 14, it is not limited only to that. A
polarization plate 61 of the display element 60 neighboring to the
retardation control liquid crystal cell 80 may be used as the
polarization plate of the retardation control liquid crystal cell
80, for example. Thereby, the number of polarization plates used
for the image display device 3 can be decreased, so that it is
possible to reduce the thickness of the image display device 3.
[0151] With such structure, the alignment state of the sandwiched
liquid crystal molecules can be changed by applying a voltage
between the transparent electrodes 88, 89 loaded to the transparent
substrates 83, 85, so that the birefringence amount of the liquid
crystal can be adjusted. Further, the viewing angle property of the
emission light can be changed through adjusting the birefringence
amount, thereby making it possible to change the wide vision
display and the narrow vision display of the image display device.
When a voltage is applied between the transparent substrates 83 and
85, the birefringence amount of the liquid crystal is decreased.
Thus, the viewing angle of the emission light from the retardation
control liquid crystal cell 80 becomes narrow. As a result, the
display of the image display device 3 is set to a narrow vision
display state.
[0152] A fault in changing the viewing angle of the image display
device 3 according to the fifth exemplary embodiment is generated
in accordance with a fault generated in the retardation control
liquid crystal cell 80. The retardation control liquid crystal cell
80 also uses a liquid crystal. Thus, when the birefringence
retardation of the liquid crystal becomes decreased by heating and
the temperature becomes high, the phase is turned to an isotropic
phase. Therefore, the birefringence retardation of the liquid
crystal layer can be adjusted without applying a voltage, through
heating the liquid crystal in the manner described above. As a
result, it is possible to forcibly set the image display device to
a narrow vision display by operating the transparent heater 50
through supplying the power thereto from a power supply circuit (by
using a narrow vision forcible setting module formed with the
transparent heater and the power supply circuit) when there is a
fault. As a result, it is possible to prevent leakage of the
information displayed on the display screen.
[0153] Next, FIG. 15 shows a drive control system of the image
display device 3 according to the fifth exemplary embodiment.
[0154] The operation of the image display device 3 is controlled by
a control module (e.g., CPU) 17. Note here that a power supply
switch 16 connected to the control module 17, the backlight 10, the
forcible heating mechanism 50, the display element 60, the electric
current detection element 70A, and the fault judging module 75 have
the same functions as the respective members under the same
reference numerals of the image display device 1 described in the
first exemplary embodiment.
[0155] As a difference with respect to the drive control system of
the first exemplary embodiment, the retardation control liquid
crystal cell 80 is provided to the drive control system of the
fifth exemplary embodiment as the viewing angel changing
element.
[0156] Illuminating the display element 60 under controls of the
control module 17 at the rise of the power upon an on-operation of
the power supply switch 16, setting of the wide vision display
state when the device is not being used, setting of the narrow
vision display when the device is being used, etc., are same as the
processing setting described in the first exemplary embodiment. In
the fifth exemplary embodiment, a voltage is applied to the voltage
applying electrodes (transparent electrodes) 88 and 89 when
changing to a narrow vision display.
[0157] The electric current flown into the retardation control
liquid crystal cell 80 is detected by the electric current
detection element 70A, and the detected electric current value is
sent to the fault judging module 75. Electric current values
(electric current values under a normal operation) flowing into the
retardation control liquid crystal cell 80 for a wide vision
display and a narrow vision display are stored in advance to the
fault judging module 75. The fault judging module 75 compares the
drive electric current value of the retardation control liquid
crystal cell 80 detected by the electric current detection element
70A with the stored electric current values, and judges whether or
not there is a fault generated in the retardation control liquid
crystal cell 80. The judgment result is transmitted to the control
module 17. When it is judged as a result of judgment that there is
a fault, the control module 17 stops supply of the voltage to the
transparent electrodes 88, 89, and heats the retardation control
liquid crystal cell 80 by operating the forcible heating mechanism
50 to perform a control for forcibly changing the display of the
image outputted from the display element 60 of the image display
device 3 to a narrow vision display state. Through setting the
alignment of the liquid crystal to an isotropic alignment through
decreasing the birefringence retardation of the liquid crystal
layer 84 by heating the retardation control liquid crystal cell 80,
the image display device 3 can be set to a narrow vision display
state without applying a voltage to the retardation control liquid
crystal cell 80.
[0158] Other structures and operation effects thereof are the same
as those of the case of the first exemplary embodiment described
above.
Sixth Exemplary Embodiment
[0159] Next, a sixth exemplary embodiment of the image display
device according to the present invention will be described by
referring to FIG. 16.
[0160] As shown in FIG. 16, an image display device 4 according to
the sixth exemplary embodiment is formed by including: a backlight
10; a retardation control liquid crystal cell (viewing angle
changing element) 80 for electrically changing the viewing angle
range, which is provided on the upper side of the backlight 10; and
a non-luminance type display element 60 provided on the upper side
of the retardation control liquid crystal cell 80. That is, the
image display device 4 is different from the image display device 2
of the second exemplary embodiment in respect that the same
retardation control liquid crystal cell 80 as that of the image
display device 3 of the fifth exemplary embodiment shown in FIG. 14
is used instead of the viewing angle changing element 20 of the
image display device 2 according to the second exemplary embodiment
shown in FIG. 8.
[0161] In the image display device 4 according to the sixth
exemplary embodiment, the members under the same reference numerals
as those of the respective members of the image display device 2
described in the second exemplary embodiment have the same
functions and exhibit the same operational effects. Further, the
retardation control liquid crystal cell 80 has the same functions
and exhibits the same operational effects as those of the
retardation control liquid crystal cell 80 used in the fifth
exemplary embodiment. In a case where there is a fault generated in
the retardation control liquid crystal cell 80, the image display
device 4 having such structure can detect the fault instantly.
Therefore, it is possible to prevent the use of the device remained
in a fault state, so that leakage of the information displayed on
the display screen can be prevented. Other structures and operation
effects thereof are the same as those of the case of the second
exemplary embodiment described above.
Seventh Exemplary Embodiment
[0162] Next, a seventh exemplary embodiment of the image display
device according to the present invention will be described by
referring to FIG. 17.
[0163] Like the structure of the image display device 1 according
to the first exemplary embodiment of the present invention, an
image display device 5 according to the seventh exemplary
embodiment is formed by including: a backlight 10; a viewing angle
changing element 20; a transparent heater 50; and a display element
60. However, the image display device 5 according to the seventh
exemplary embodiment includes an input device 90 on the upper side
of the display element 60, as shown in FIG. 17. In this respect,
the image display device 5 is different from the image display
device 1 of the first exemplary embodiment. The input device 90 is
formed with an input unit 91 and a frame 92. The input device 90
may be of any types such as a resistance type, an electrostatic
induction type, an infrared ray type, etc., as long as it is a type
capable of recognizing the display image of the image display
device 5.
[0164] In addition to those, the image display device 5 also
includes an electric current detection element 70A for monitoring
the state of the viewing angle changing element 20 and a fault
judging module 75 for judging whether or not there is a fault
generated in the viewing angle changing element 20 based on the
measurement value detected by the detection element, as in the case
of the image display device 1 of the first exemplary embodiment.
Each of the structural members of the image display device 5 under
same reference numerals as those of the respective structural
members constituting the image display device 1 of the first
exemplary embodiment has the same functions and exhibits the same
operations and effects.
[0165] Through having such structure, it is possible with the
seventh exemplary embodiment to achieve the image display device 5
to which the input function is provided. Further, even when there
is a fault generated in the transparent-scattering changing element
40 of the viewing angle changing element 20, it is possible to
detect the occurrence of the fault instantly and to set the
transparent-scattering changing element 40 to a transparent state
by heating it. Thus, the image display device 5 can be forcibly set
to a narrow vision display, so that leakage of the user information
inputted via the input device 90 can be prevented.
[0166] Other structures and operation effects thereof are the same
as those of the case of the first exemplary embodiment described
above.
Eighth Exemplary Embodiment
[0167] Next, an eighth exemplary embodiment of the image display
device according to the present invention will be described by
referring to FIG. 18-FIG. 21. Note here that same reference
numerals are applied to the same structural members as those of the
first exemplary embodiment described above.
[0168] As shown in FIG. 18, an image display device 6 according to
the eighth exemplary embodiment is formed by disposing a
photosensor element (operation state detection element) 70C
constituted with an optical sensor 71 having a light-ray direction
control element (oblique louver) 72 on the surface (the upper side
of the non-luminance type display element 60) of the image display
device 1 of the first exemplary embodiment shown in FIG. 1. The
members under the same reference numerals as those of the members
of the image display device 1 of the first exemplary embodiment
shown in FIG. 1 have the same functions and exhibit the same
operational effects.
[0169] As shown in FIG. 18, the photosensor element 70C is formed
by having the light-ray direction control element 72 such as an
oblique louver provided to the optical sensor 71 such as a
photodiode. With the use of the photosensor element (oblique
direction photosensor) 70C formed by the optical sensor 71 having
the oblique lover 72 loaded thereon, the amount of oblique light
emitted from the display element 60 can be monitored.
[0170] In the section of the oblique louver 72, a transparent layer
73 and a light shielding layer 74 are arranged alternately and in
parallel as shown in FIG. 19A, and those layers are tilted with
respect to the thickness direction (the vertical direction of the
drawing) of the oblique louver 72. Through adjusting the tilt
angle, it is possible to control the transmittable incident angles,
as shown in FIG. 19B.
[0171] With such structure, the photosensor element (oblique
direction photosensor) 70C exhibits the transmittance property for
the incident light as shown in FIG. 20. Light making incident on
the photosensor element 70C in the perpendicular direction (at an
angle of 0 degree) is absorbed by the light shielding layer 74 and
cannot transmit therethrough when passing the oblique louver 72,
and only light making incident on the photosensor element 70C in
the oblique direction can transmit. As described, the photosensor
element 70C blocks the light from the front direction
(perpendicular direction) and transmits only the light from the
oblique direction. Therefore, the photosensor element 70C can
detect the luminance change in the oblique direction of the image
display device 6 when changing the viewing angles, so that it is
possible to discriminate the narrow vision display or the wide
vision display of the image display device 6.
[0172] The photosensor element 70C is desired to be placed in the
corner of the display section of the non-luminous type display
element 60. Since the transmittable incident angles can be
controlled by adjusting the tilt angle as described above, the
photosensor element can be placed on the outside of the display
section by setting the tilt angle still greater.
[0173] This makes it possible to detect a fault in changing of the
viewing angle without blocking the display region (displayed
information) of the display element 60. Further, while the oblique
louver 72 is loaded to the optical sensor 71 herein, it is not
limited only to the oblique louver 72 as long as it is an element
which detects the light in the oblique direction. Furthermore,
while a photodiode is used as the optical sensor 71 herein as a way
of example, the optical sensor is not limited only to that as long
as it is an element which can detect the light amount.
[0174] As described, by employing the structure in which the
photosensor element 70C is placed on the upper side of the
non-luminous display element 60, it is possible to judge an
occurrence of a fault through detecting the luminance of the image
display device 6 in all of the fault modes (the fault modes 1-4
described in the first exemplary embodiment).
[0175] For example, in the fault modes 1, 2, and 3, the
transparent-scattering changing element 40 turns to a scattering
state because of a fault when the display of the image display
device 6 is supposed to be a narrow vision display, and the
luminance becomes higher than the luminance set value of a normal
operation for the narrow vision display measured in advance.
Particularly, in the fault modes 2 and 3, a voltage cannot be
applied to the transparent-scattering changing element 40.
Therefore, the luminance becomes higher than the case of the fault
mode 1.
[0176] Further, an overvoltage is applied in the fault mode 4, so
that the image display device 6 is fixed to a narrow vision display
state. Thus, even when a control signal for changing to a wide
vision display is received, the transparent-scattering changing
element 40 does not change but stays in a transparent state. As a
result, the luminance detected by the photosensor element 70C
becomes lower than the luminance set value of a normal operation
for the wide vision display measured in advance. Therefore, it is
possible to detect the fault based on the comparison result of the
detected luminance values.
[0177] Next, the viewing angle changing processing operation of the
image display device 6 will be described.
[0178] First, as shown in a flowchart of FIG. 21, light of the
oblique direction out of the light emitted from the display element
60 is detected and measured by the photosensor element 70C placed
on the upper side of the non-luminance type display element 60
(step S301). The measured luminance value is sent to the fault
judging module 75.
[0179] Desired light amounts (luminance values) for the wide vision
display and the narrow vision display under a normal operation of
the image display device 6 are measured by the photosensor element
70C in advance, and the measured values (luminance reference
values) are stored in the fault judging module 75 that is provided
inside the image display device 6. The fault judging module 75
compares the stored luminance reference values for the wide vision
display and the narrow vision display with the luminance value
detected by the photosensor element 70C (step S302).
[0180] Then, it is judged whether or not there is a fault generated
in the viewing angle changing element 20 based on the comparison
result (step S303). Specifically, in a case where the difference
between the measured light amount and the prestored light amount
under a normal operation is within a prescribed range specified in
advance (e.g., within .+-.10% of the normal operation light amount
value), it is judged that there is no fault being generated in the
viewing angle changing element 20. When the difference is out of
the prescribed range, it is judged that there is a fault being
generated.
[0181] When it is found as a result of judgment that there is no
fault generated in the viewing angle changing element 20, the
processing operation is ended. In the meantime, when there is a
fault generated in the viewing angle changing element 20, the
display of the image outputted from the display element 60 is
forcibly changed to the narrow vision display by the changing
module (50) (step S304). In a case where the transparent-scattering
changing element 40 is electrically changed to a scattering state
and the image display device 6 is set to a wide vision display
state due to a fault generated in the viewing angle changing
element 20, a risk of having the information (a secret code number,
etc., of the user) displayed on the screen of the image display
device 6 leaked to the other users in the surrounding is increased.
Thus, the viewing angle changing element 20 (transparent-scattering
changing element 40) is heated by operating the forcible heating
mechanism (transparent heater) 50. Through heating, it is possible
to turn the transparent-scattering changing element 40 to a
transparent state and to forcibly change the display of the image
display device 6 to a narrow vision display state. As a result,
leakage of the user information can be prevented.
[0182] The image display device 6 can also be operated as
follows.
[0183] The stored luminance values of each of the display states
are compared with the detected luminance value to judge whether or
not there is a fault generated in the viewing angle changing
element 20 in the same manner as the operation steps described
above. When judged that there is a fault, the electrode terminals
(voltage forcible applying mechanism) for the case of a fault
provided to the transparent-scattering changing element 40 is
operated as a drive source of the transparent-scattering changing
element 40. This makes it possible to drive the
transparent-scattering changing element 40, even when there is a
fault generated in the viewing angle changing element 20.
Therefore, the image display device 6 can be forcibly changed to
the narrow vision display, and leakage of the information displayed
on the display screen can also be prevented even at the time of
having a fault.
[0184] With the eighth exemplary embodiment, it is possible to
detect the light of the oblique direction with a limited space by
loading the light-ray direction control element 72 to the optical
sensor 71 which monitors the viewing angle changing element 20.
Thus, a fault generated in the viewing angle changing element 20
can be detected easily. Further, when it is judged that there is a
fault, the image display device can be set to the narrow vision
display forcibly, so that leakage of the information on the screen
can be prevented.
[0185] Other structures and operation effects thereof are the same
as those of the case of the first exemplary embodiment described
above.
Ninth Exemplary Embodiment
[0186] Next, a ninth exemplary embodiment of the image display
device according to the present invention will be described by
referring to FIG. 22.
[0187] As shown in FIG. 22, an image display device 7 according to
the ninth exemplary embodiment of the present invention is
characterized to have an input device 90 that is equivalent to the
input device 90 of the seventh exemplary embodiment (see FIG. 17),
which is provided on the image output face (on the upper side of
the photosensor (operation state detection element) 70C) of the
image display device 6 of the eighth exemplary embodiment (FIG. 18)
described above.
[0188] In the image display device 7 according to the ninth
exemplary embodiment, each of the structural members under same
reference numerals as those of the respective structural members
constituting the image display device 6 of the eighth exemplary
embodiment has the same functions and exhibits the same operational
effects. Further, the input device 90 has the same functions and
exhibits the same operational effects as those of the input device
90 used in the seventh exemplary embodiment.
[0189] Through having such structure, it is possible with the ninth
exemplary embodiment to achieve the image display device 7 to which
the input function is provided. Further, through placing the input
device 90 on the surface of the image display device 7, the
photosensor element 70C placed on the display element 60 can be
housed under the frame 92 of the input device 90. This makes it
possible to overcome a sense of visually uncomfortable feeling felt
by observers because the photosensor element 70C is reflected
inside the display screen. Further, since the photosensor element
70C is not visually recognized by the observers, restriction in
terms of design as the image display device with the input device
can be eased greatly. Furthermore, even when there is a fault
generated in the transparent-scattering changing element 40 of the
viewing angle changing element 20, the occurrence of the fault can
be detected instantly and the transparent-scattering changing
element 40 is set to a transparent state by heating. Thus, the
image display device 7 can be set to a narrow vision display
forcibly, so that leakage of the user information inputted via the
input device 90 can be prevented.
[0190] Other structures and operation effects thereof are the same
as those of the case of the eighth exemplary embodiment described
above.
Tenth Exemplary Embodiment
[0191] Next, a tenth exemplary embodiment of the image display
device according to the present invention will be described by
referring to FIG. 23.
[0192] An image display device of the tenth exemplary embodiment is
characterized to be loaded on an electronic apparatus. As shown in
FIG. 23, an image display device 99 is loaded on an ATM (electronic
apparatus) 98 that is placed at a bank or a convenience store, for
example. The user can deposit and withdraw money by operating the
display screen (e.g., a touch panel screen) of the image display
device 99. As the image display device 99 loaded on the electronic
apparatus 98, the image display devices according to the first to
ninth exemplary embodiments can be used, for example.
[0193] Even when the image display devices of the first to ninth
exemplary embodiments described above are loaded on the ATM
(electronic apparatus) 98, each of the image display devices can
exhibit the same operational effects as those depicted in the
respective embodiments. Thus, the electronic apparatus 98 can
forcibly set the display of the image outputted from the display
element to a narrow vision display state even when there is a fault
generated in the viewing angle changing element of the image
display device that is loaded on the electronic apparatus.
Therefore, it is possible to securely prevent leakage of the user
information displayed on the display screen.
[0194] While the present invention has been described by referring
to some of the exemplary embodiments, the image display device and
the electronic apparatus using the same are not limited only to
those exemplary embodiments. It is to be noted that the present
invention includes the image display device and the electronic
apparatus achieved by applying various kinds of modifications and
changes to the structures of the exemplary embodiments described
above.
[0195] A part of or a whole part of the functions (contents)
executed by each of the structural members of the image display
devices of each of the above-described exemplary embodiments may be
built as a program to have it executed by a computer. Even in such
case, the same effects as those of the exemplary embodiments can be
achieved.
[0196] The new technical contents of each of the above-described
exemplary embodiments can be summarized as follows. While a part or
a whole part of the exemplary embodiments can be depicted as
follows, it is to be noted that the present invention is not
necessarily limited to those depicted below.
(Supplementary Note 1)
[0197] An image display device, including a display device main
body which includes a display element for outputting/displaying
prescribed image information to outside and a viewing angle
changing element for setting to change outputted display of image
information on the display element at least from a wide vision
display to a narrow vision display based on a changing command from
the outside, wherein: the display device main body is provided with
an operation state detection element which detects an operation
state of the viewing angle changing element; and the viewing angle
changing element is provided with a narrow vision forcible setting
module which operates to forcibly set the outputted display of the
display element to a narrow vision display state, when the
operation state detected by the operation state detection element
is a fault state.
(Supplementary Note 2)
[0198] The image display device depicted in Supplementary Note 1,
wherein the narrow vision forcible setting module is formed by a
forcible heating mechanism which heats the viewing angle changing
element.
(Supplementary Note 3)
[0199] The image display device depicted in Supplementary Note 1,
wherein the narrow vision forcible setting module is a voltage
forcible applying mechanism which applies a voltage to the viewing
angle changing element.
(Supplementary Note 4)
[0200] The image display device depicted in Supplementary Note 2,
wherein the forcible heating mechanism is formed by a transparent
heater made with a transparent electrode and a power supply circuit
which supplies power to the transparent heater.
(Supplementary Note 5)
[0201] The image display device depicted in Supplementary Note 3,
wherein the voltage forcible applying mechanism is formed by a pair
of transparent electrodes covered by an insulating layer and
insulated from a voltage applying electrode that is used under a
normal state where no fault is generated.
(Supplementary Note 6)
[0202] The image display device depicted in Supplementary Note 3,
wherein the voltage forcible applying mechanism includes another
voltage supplying terminal that is independent from a terminal for
supplying a voltage used under a normal state where no fault is
generated.
(Supplementary Note 7)
[0203] The image display device depicted in any one of
Supplementary Notes 1-6, which includes a fault judging module,
wherein: the operation state detection element is formed by an
oblique direction photosensor provided at an end of an output
display face side of the display element for detecting light
outputted in oblique directions from the output display face; and
the fault judging module judges whether or not there is a fault
generated in the viewing angle changing element based on a light
detected value acquired by the oblique direction photosensor.
(Supplementary Note 8)
[0204] The image display device depicted in Supplementary Note 7,
wherein the oblique direction photosensor is formed by a normal
photosensor and a light-ray direction control element provided on a
light-receiving face of the oblique direction photosensor.
(Supplementary Note 9)
[0205] The image display device depicted in any one of
Supplementary Notes 1-6, which includes a fault judging module,
wherein: the operation state detection element is formed by an
electric current detection element which measures an electric
current flown in the viewing angle changing element; and the fault
judging module judges whether or not there is a fault generated in
the viewing angle changing element based on an electric current
detected value acquired by the electric current detection
element.
(Supplementary Note 10)
[0206] The image display device depicted in any one of
Supplementary Notes 1-9, which includes an input device made with a
transparent member for inputting information which is provided on
an image information output/display side of the display device main
body.
(Supplementary Note 11)
[0207] An electronic apparatus, including the image display device
depicted in any one of Supplementary Notes 1-10 loaded for
displaying information.
(Supplementary Note 12)
[0208] A display output control method used for an image display
device including a display device main body which includes a
display element for outputting/displaying prescribed image
information to outside and a viewing angle changing element for
setting to change outputted display of image information on the
display element at least from a wide vision display to a narrow
vision display based on a changing command from the outside, and
the method includes: detecting an electric current flowing into the
viewing angle changing element by an electric current detection
element provided to the display device main body; executing
comparison processing for comparing the electric current value
detected by the electric current detection element with an electric
current value under a normal operation measured and stored in
advance, and judgment processing by a fault judging module provided
to the display device main body for judging whether or not there is
a fault generated in the viewing angle changing element based on a
result of the comparison; and setting the output display of the
display element to a narrow vision display state forcibly by a
narrow vision forcible setting module that is provided to the
viewing angle changing element, when it is judged by the fault
judging module that there is a fault.
(Supplementary Note 13)
[0209] The display output control method for the image display
device depicted in Supplementary Note 12, wherein the narrow vision
forcible setting module forcibly sets the outputted display of the
display element to a narrow vision display state by heating the
viewing angle changing element, when it is judged by the fault
judging module that there is a fault.
(Supplementary Note 14)
[0210] The display output control method for the image display
device depicted in Supplementary Note 12, wherein, in a case where
the narrow vision forcible setting module is a voltage applying
electrode used exclusively for the time of having a fault provided
separately from a voltage applying electrode used under a normal
state where no fault is generated, the outputted display of the
display element is forcibly set to a narrow vision display state
through applying a voltage to the viewing angle changing element by
the voltage applying electrode used exclusively for the time of
having a fault, when it is judged by the fault judging module that
there is a fault.
(Supplementary Note 15)
[0211] A display output control program used for an image display
device including a display device main body which includes a
display element for outputting/displaying prescribed information to
outside and a viewing angle changing element for setting to change
outputted display of image information on the display element at
least from a wide vision display to a narrow vision display based
on a changing command from the outside, and the program causes a
computer to execute: a fault judgment processing function which
compares an electric current value detected by an electric current
value detection element for detecting a drive electric current for
the viewing angle changing element with an electric current value
under a normal operation stored in advance, and judges whether or
not there is a fault generated in the viewing angle changing
element based on a result of the comparison; and a narrow vision
forcible changing function which forcibly sets the display of the
display element to a narrow vision display state, when it is judged
by the fault judgment processing function that there is a
fault.
INDUSTRIAL APPLICABILITY
[0212] The present invention can be utilized as the display device
of industrial information terminals such as ATMs and mobile
information terminals such as mobile telephones and notebook
personal computers.
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