DISPLAY METHOD, DISPLAY DEVICE, ELECTRONIC SYSTEM, AND
LIGHTING UNIT
BACKGROUND
[0001 ] The present disclosure relates to a display device by which display
of a stereoscopic image is allowed, an electronic system which includes the
display device, a lighting unit which is loaded on the display device, and a
display method by which a stereoscopic image is displayed by using the
display device.
[0002 ] A display device by which implementation of stereoscopic image
display is allowed has attracted notice in recent years. In stereoscopic image
display, a left-eye image and a right-eye image between which parallax is
present (which are different from each other in perspective) are displayed and
a viewer is allowed to recognize the images as one deep stereoscopic image by
observing the images with his/her left and right eyes. In addition, a display
device which allows provision of a more natural stereoscopic image for a
viewer by displaying three or more images among which parallax is present is
also developed.
[0003 ] Display devices as mentioned above are generally divided into one
type which would require dedicated glasses and another type which would not
require any glasses. A viewer may have an impression that use of the
dedicated glasses is troublesome and hence a display device which would not
require any dedicated glasses is preferred. As a display device which would
not require any dedicated glasses, for example, a lenticular lens system device
and a parallax barrier system device are available. The devices of the above
mentioned systems are configured such that a plurality of images (perspective
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images) among which parallax is present are displayed together on an image
display panel such that an image which is observed changes as a relative
positional relation (an angle) between the display device and the perspective
of the viewer changes. As an example of a display device of the parallax
barrier system, a display device disclosed, for example, in Japanese
Unexamined Patent Application Publication No. H03-119889 may be given.
SUMMARY
[0004] Incidentally, an illumination light source which is called a
backlight is used in the above mentioned lenticular lens system and parallax
barrier system display devices so as to make illumination light from the
backlight selectively transmit through a lenticular lens or a parallax barrier.
Therefore, it is desirable to increase the utilization efficiency of the
illumination light from the backlight. In addition, when stereoscopic image
display has been performed by using the lenticular lens or the parallax barrier,
a light transmitting region through which the illumination light from the
backlight passes and a light shielding region where the illumination light is
shielded are fixedly positioned on an image display panel. Therefore, when
the orientation of the display device is changed (for example, when the
display device is rotated on an optical axis as a central axis) relative to the
perspective position of a viewer, it may become difficult for the viewer to
visually recognize an appropriate stereoscopic image. Although a method of
mechanically changing relative positions of the image display panel and the
lenticular lens or the parallax barrier may be contemplated, this method may
induce complication and large-sizing of a general configuration of the display
device itself.
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[0005] It is desirable to provide a display device which allows formation
of a favorable stereoscopic image in accordance with the attitude of a viewer,
an electronic system which includes the display device, and a lighting unit
which is loaded on the display device. It is also desirable to provide a
display method of implementing favorable stereoscopic display in accordance
with the attitude of a viewer by using a display device as mentioned above.
[0006] A display method according to an embodiment of the present
disclosure displays stereoscopic images with use of a display device provided
with a lighting unit and a display section. The lighting unit includes a
plurality of two-dimensionally-arrayed light emitting sections, and the display
section performs image display through utilizing light from the light emitting
sections. The method includes: detecting an attitude of the display device
relative to a viewer; driving the plurality of light emitting sections on an
individual basis, to allow an emission pattern to be formed according to the
attitude of the display device; and displaying a plurality of perspective images
all together, according to the attitude of the display device on the display
section based on an external image signal.
[0007] In the display method according to the embodiment of the present
disclosure, the attitude of the display device relative to the viewer, that is, a
state of orientation, an angle or the like of the display device relative to the
viewer is detected and light is emitted from the plurality of light emitting
sections in accordance with the state to form a predetermined emission pattern
and to display the plurality of perspective images. As a result, the quality of
the stereoscopic image which is visually recognized by the viewer is favorably
maintained regardless of a change in the orientation or the angle of the display
device relative to the viewer.
[0008] A display device according to an embodiment of the present
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disclosure includes: a lighting unit including a plurality of
two-dimensionally-arrayed light emitting sections, and a drive section driving
the plurality of light emitting sections on an individual basis; and a display
section including a plurality of pixels to perform image display through
utilizing light from the light emitting sections.
[0009] An electronic system according an embodiment of the present
disclosure is provided with a display device. The display device includes: a
lighting unit including a plurality of two-dimensionally-arrayed light emitting
sections, and a drive section driving the plurality of light emitting sections on
an individual basis; and a display section including a plurality of pixels to
perform image display through utilizing light from the light emitting sections.
[0010] In the display device and the electronic system according to the
embodiments of the present disclosure, in the lighting unit, the plurality of
two-dimensionally-arrayed light emitting sections are turned on or turned off
by the drive section on an individual basis. Thus, switching between
two-dimensional image display (planar image display) and three-dimensional
image display (stereoscopic image display) is possible by utilizing the
lighting unit as a backlight of the display section. That is, in the
stereoscopic image display, an emission pattern which is obtained by
arranging a plurality of light emitting sections which are located one after
another like a strip in one direction so as to be adjacent to one another at
predetermined intervals is formed in the lighting unit to generate a plurality of
rays of linear-shaped illumination light and to display the plurality of
perspective images all together on the display section. While, in the
two-dimensional image display, for example, all the light emitting sections are
turned on in the lighting unit to generate uniform illumination light which is
reduced in variation in luminance over the entire surface.
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[0011] A lighting unit according to an embodiment of the present
disclosure is provided for a display device. The lighting unit includes: a
plurality of two-dimensionally-arrayed light emitting sections; and a drive
section driving the plurality of light emitting sections on an individual basis.
[0012] In the lighting unit according to the embodiment of the present
disclosure, the plurality of two-dimensionally-arrayed light emitting sections
are turned on or turned off by the drive section on an individual basis. Thus,
formation of an arbitrary emission pattern is possible at an arbitrary timing.
[0013] According to the display method of the embodiment of the present
disclosure, since the attitude of the display device relative to the viewer is
detected and the formation of the emission pattern of the lighting unit and the
display of the perspective image are performed in accordance with it, it
becomes possible for the viewer to recognize a favorable stereoscopic image
even when the display device has been rotated in an arbitrary direction.
[0014] According to the lighting unit of the embodiment of the present
disclosure, it is possible to form the emission pattern obtained by arranging a
plurality of light emitting sections which are located one after another like a
strip in one direction at predetermined intervals, thereby generating a
plurality of rays of linear-shaped illumination light. Therefore, according to
the display device and the electronic system of the present disclosure in which
the lighting unit is used as the backlight, it is possible to make images that the
viewer recognizes with his/her left and right eyes different from each other in
accordance with a relative positional relation (an angle) among the emission
pattern, the display section, and the perspective position of each of the
viewer's left and right eyes. As a result, it becomes possible for the viewer
to recognize a stereoscopic image. Here, since it is allowed to arbitrarily set
a direction in which the linear-shaped illumination light extends, it becomes
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possible to address a change in relative relation between the display section
and the perspective position of each of the viewer's left and right eyes. In
addition, since it is allowed to form an arbitrary emission pattern at an
arbitrary timing, it becomes also possible to handle time-division display.
[0015] It is to be understood that both the foregoing general description
and the following detailed description are exemplary, and are intended to
provide further explanation of the technology as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The accompanying drawings are included to provide a further
understanding of the disclosure, and are incorporated in and constitute a part
of this specification. The drawings illustrate embodiment, and together with
the specification, serve to explain the principles of the technology.
[0017] FIG. 1 is a block diagram illustrating an example of a
configuration of a display device according to a first embodiment of the
present disclosure.
[0018] FIG. 2 is an explanatory diagram illustrating an example of a
configuration of a display section and a display drive section illustrated in FIG.
1.
[0019] FIG. 3A and FIG. 3B are explanatory diagrams illustrating an
example of a configuration of a pixel circuit and one example of a sectional
configuration of a pixel illustrated in FIG. 2.
[0020] FIG. 4 is a sectional diagram illustrating an example of a
configuration of the display section and a backlight illustrated in FIG. 1.
[0021] FIG. 5 is a sectional diagram illustrating an example of a
configuration of a light modulation element illustrated in FIG. 4.
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[0022] FIG. 6 is a perspective view illustrating an example of an electrode
structure of the light modulation element illustrated in FIG. 5.
[0023 ] FIG. 7A, FIG. 7B, and FIG. 7C are schematic diagrams illustrating
one example of operation of the light modulation element illustrated in FIG. 4.
[0024] FIG. 8A, FIG. 8B, and FIG. 8C are schematic diagram illustrating
another example of operation of the light modulation element illustrated in
FIG. 4.
[0025] FIG. 9 is a schematic diagram illustrating an example of operation
of the backlight illustrated in FIG. 1.
[0026] FIG. 10 is a schematic diagram illustrating an example of a first
pattern of a lower electrode to which a voltage is selectively applied when
three-dimensional display is to be performed by the light modulation element
illustrated in FIG. 4.
[0027] FIG. 11 is a schematic diagram illustrating an example of an
emission pattern and linear-shaped illumination light which are formed by the
backlight illustrated in FIG. 1.
[0028] FIG. 12 is a schematic diagram illustrating an example of
three-dimensional display by the display device illustrated in FIG. 1.
[0029] FIG. 13 is a schematic diagram illustrating an example of
two-dimensional display by the display device illustrated in FIG. 1.
[0030 ] FIG. 14 is another schematic diagram illustrating an example of a
second pattern of the lower electrode to which a voltage is selectively applied
when three-dimensional display is to be performed by the light modulation
element illustrated in FIG. 4.
[0031 ] FIG. 15 is another schematic diagram illustrating an example of an
emission pattern and linear-shaped illumination light which are formed by the
backlight illustrated in FIG. 1.
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[0032] FIG. 16 is another schematic diagram illustrating an example of
three-dimensional display by the display device illustrated in FIG. 1.
[0033] FIG. 17 is a further schematic diagram illustrating an example of a
third pattern of the lower electrode to which a voltage is selectively applied
when three-dimensional display is to be performed by the light modulation
element illustrated in FIG. 4.
[0034] FIG. 18 is a perspective view illustrating an example of an
electrode structure of the light modulation element as a modification.
[0035] FIG. 19 is a sectional diagram illustrating an example of a
configuration of electronic paper used in a backlight of a display device
according to a second embodiment of the present disclosure.
[0036] FIG. 20 is a sectional diagram illustrating an example of an
operation of the electronic paper illustrated in FIG. 19.
[0037] FIG. 21 is a sectional diagram illustrating an example of a
configuration of a backlight in a display device according to a third
embodiment of the present disclosure.
[0038] FIG. 22 is a sectional diagram illustrating an example of a
configuration of a backlight in a display device according to a fourth
embodiment of the present disclosure.
[0039] FIG. 23A and FIG. 23B are sectional diagrams illustrating an
example of a configuration of a backlight in a display device according to a
fifth embodiment of the present disclosure.
[0040 ] FIG. 24A and FIG. 24B are perspective views illustrating an
example of a configuration of an electronic system which uses the display
device.
DETAILED DESCRIPTION
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[0041] Next, preferred embodiments will be described in detail with
reference to the accompanying drawings. It is to be noted that description
will be made in the following order.
1. First Embodiment (FIG. 1 to FIG. 18)
An example (a display device ) in which a backlight including a
light modulation element ( a horizontal PDLC) is used
2. Second Embodiment ( FIG. 19 and FIG. 20)
An example (a display device ) in which a backlight including an
electrophoresis element is used
3. Third Embodiment (FIG. 21)
An example (a display device ) in which a backlight including an
organic light emitting element is used
4. Fourth Embodiment (FIG. 22)
An example (a display device ) in which a backlight including a
light emitting diode is used.
5. Fifth Embodiment (FIGs. 23A and 23B)
An example (a display device ) in which a backlight including an
electronic particulate element is used.
6. Sixth Embodiment (FIGS. 24A and 24B)
An example (electronic system ) to which a display device is
applied
[First Embodiment]
[General Configuration]
[0042] FIG. 1 is a block diagram illustrating an example of a
configuration of a display device 100 according to a first embodiment. The
display device 100 is of the type that both of stereoscopic display
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(three-dimensional display) and normal display (two-dimensional display)
may be implemented. The display device 100 includes a sensor section 10, a
display section 20, a backlight 30, a control section 40, a display drive section
50, and a backlight drive section 60.
[0043] The sensor section 10 functions to successively detect the attitude
of the display device 100 on the basis of an instruction from the control
section 40 and to send attitude information on the detected attitude to the
control section 40. The sensor section 10 is adapted to detect the attitude
(the orientation and the angle) of the display device 100 relative to a viewer
and is, for example, an acceleration sensor or an image recognition device.
When, for example, the image recognition device is used as the sensor section
10, information used to display an image in an appropriately oriented state on
the display section 20 may be obtained by discriminating the positions of the
viewer's left and right eyes.
[0044] The control section 40 is a circuit configured to supply control
signals respectively to the display drive section 50 and the backlight drive
section 60 on the basis of an external image signal Vdisp supplied from the
outside and the attitude information supplied from the sensor section 10 and to
control such that the sections 50 and 60 operate in synchronization with each
other. Specifically, the control section 40 is configured to supply an image
signal S1 based on the image signal Vdisp to the display drive section 50 and
supply a backlight control signal S2 to the backlight drive section 60. The
control section 40 also controls the operation of the sensor section 10.
[0045] The display drive section 50 is adapted to drive the display section
20 on the basis of the image signal SI supplied from the control section 40.
The display section 20 is adapted to perform image display by driving a liquid
crystal element and modulating light radiated from the backlight 30.
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[0046] The backlight drive section 60 is adapted to drive the backlight 30
on the basis of the backlight control signal S2 supplied from the control
section 40. The backlight 30 is a lighting unit which has a function of
irradiating the display section 20 with planar illumination light or a plurality
of rays of linear-shaped illumination light from behind.
[0047] The display section 20 is, for example, a transmission type liquid
crystal display panel (LCD) each pixel of which is driven in accordance with
the image signal SI and has a structure that a liquid crystal layer is
sandwiched by a pair of transparent substrates.
[0048] FIG. 2 illustrates an example of a block diagram of the display
drive section 50 and the display section 20. Pixels Pix are arranged in a
matrix on the display section 20. The display drive section 50 includes a
timing control section 51, a gate driver 52, and a data driver 53. The timing
control section 51 is adapted to control drive timings of the gate driver 52 and
the data driver 53 and to supply the image signal Si supplied from the control
section 40 to the data driver 53 as an image signal S11. The gate driver 52 is
adapted to sequentially select the pixels Pix included in the display section 20
line by line in accordance with timing control by the timing control section 51
to perform line sequential scanning. The data driver 53 is adapted to supply
a pixel signal based on the image signal S I to each pixel Pix included in the
display section 20. Specifically, the data driver 53 is configured to generate
the pixel signal which is an analog signal by performing D/A (digital/analog)
conversion on the basis of the image signal Sll and to supply the generated
pixel signal to each pixel Pix.
[0049] The display section 20 is of the type that a liquid crystal material
is sealed between two transparent substrates which are made of, for example,
glass or the like. A transparent electrode which is made of, for example, ITO
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(Indium Tin Oxide) or the like is formed on a part of each transparent
substrate which faces the liquid crystal material to configure the pixel Pix
together with the liquid crystal material. Liquid crystals of, for example, VA
(vertical alignment) mode, IPS (in-plane switching) mode, and TN (twisted
nematic) mode using nematic liquid crystals are used as liquid crystal
materials of the display section 20.
[0050] FIG. 3A illustrates an example of a circuit diagram of the pixel Pis.
The pixel Pix includes a TFT (Thin Film Transistor) element Tr, a liquid
crystal element LC, and a retention volume element C. The TFT element Tr
is formed by, for example, a MOS-FET (Metal Oxide Semiconductor-Field
Effect Transistor) in which a gate is connected to a gate line G, a source is
connected to a data line D, and a drain is connected to one end of the liquid
crystal element LC and one end of the retention volume element C. One end
of the liquid crystal element LC is connected to a drain of the TFT element Tr
and its other end is grounded. One end of the retention volume element C is
connected to a drain of the TFT element Tr and its other end is connected to a
retention volume line Cs. The gate line G is connected to the gate driver 52,
and the data line D is connected to the data driver 53.
[0051] FIG. 3B illustrates a sectional configuration of the display section
20 including the pixels Pix. When viewed in section, the display section 20
has a configuration that a liquid crystal layer 203 is sealed between a drive
substrate 201 and a counter substrate 205 as illustrated in the drawing. The
drive substrate 201 is of the type that a pixel drive circuit including the above
mentioned TFT element Tr is formed, and a pixel electrode 202 is disposed on
the drive substrate 201 for every pixel Pix. Not illustrated color filter and
black matrix are formed on the counter substrate 205 and a counter electrode
204 is disposed on its surface on the side of the liquid crystal layer 203 as an
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electrode which is commonly provided for the respective pixels Pix.
Polarization plates 206A and 206B are affixed to the light incident side (here,
the backlight 30 side) and the light outgoing side (here, the side of a viewer)
of the display section 20 so as to mutually function as crossed Nicols or
parallel Nicols.
[0052 ] FIG. 4 illustrates an example of a sectional configuration of the
display device 100. It is to be noted that FIG. 4 schematically illustrates the
sectional configuration and illustrated size and shape may not be the same as
the actual ones. The backlight 30 is disposed behind the display section 20
in the display device 100 as illustrated in FIG. 4. The backlight 30
corresponds to one specific example of a "lighting unit". The backlight 30
includes, for example, a light guiding plate 1, a light source 2 which is
disposed in opposition to an end surface of the light guiding plate 1, and a
light modulation element 3 and a reflector 4 which are disposed behind the
light guiding plate 1.
[0053] The light guiding plate I is adapted to guide light from the light
source 2 onto an upper surface of the light guiding plate 1. The light guiding
plate 1 has a shape corresponding to that of the display section 20 which is
disposed so as to superpose on its surface, such as, for example, a rectangular
parallelepiped shape which is surrounded by the upper surface, a lower
surface, and end surfaces which connect together the upper and lower surfaces.
In the following, one end surface upon which light from the light source 2 is
incident will be referred to as a light incidence plane IA, in the end surfaces
of the light guiding plate 1. The light guiding plate I has a function of, for
example, scattering light which is incident from the light incidence plane IA,
making it uniform and radiating it from at least one of the upper surface and
the lower surface. Incidentally, when luminance is to be made uniform by
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modulating a voltage applied to the backlight 30, a flat light guiding plate
which is not patterned may be used as the light guiding plate 1. The light
guiding plate 1 is configured by mainly containing transparent thermoplastic
resins such as, for example, polyearbonate resins (PC), acrylic resins
(polymethyl methacrylate (PMMA)) and the like.
[0054 ] The light source 2 is a linear-shaped light source and includes, for
example, a hot cathode fluorescent lamp (HCFL), a cold cathode fluorescent
lamp (CCFL), or a plurality of LEDs (Light Emitting Diodes) which are
arrayed in a line. When the light source 2 includes the plurality of LEDs, it
is preferable that all the LEDs be white LEDs from the viewpoint of efficiency,
thinning, and uniformity. As an alternative, the light source 2 may include
red, green, and blue LEDs. The light source 2 may be disposed only at a
position opposite to one end surface of the light guiding plate 1 (see FIG. 4) or
may be disposed in opposition to two or more end surfaces of the light guiding
plate 1.
[0055] The reflector 4 is adapted to return light which leaks out from
behind the light guiding plate 1 through the light modulation element 3 toward
the light guiding plate 1 and has functions such as, for example, reflecting,
diffusing, and scattering functions. Light radiated from the light source 2
may be efficiently utilized and front luminance may be increased owing to
provision of the reflector 4. The reflector 4 is made of, for example, a
foamed PET (polyethylene telephthalate) sheet, an evaporated silver film, a
multilayer reflector film, a white PET sheet or the like. It is to be noted that
the reflector 4 may be provided on an as-needed basis and may be sometimes
omitted.
[0056] In the first embodiment, the light modulation element 3 is
disposed behind the light guiding plate 1 (on the opposite side of the display
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section 20) and is adhered to a rear surface of the light guiding plate 1, for
example, with an adhesive (not illustrated) without interposing an air layer
between them. The light modulation element 3 includes a plurality of light
modulation cells 3S (described later) serving as light emitting sections which
emit light by utilizing light which has been propagated through the light
guiding plate I from the light source 2. The light modulation element 3 is of
the type utilizing a polymer dispersed liquid crystal (PDLC) and is allowed to
form a transparent region 3A (described later) and a scattering region 3B
(described later) by active-matrix-driving the plurality of light modulation
cells 3S in arbitrary patterns along a display face of the display section 20.
The light modulation element 3 is of the type that a transparent substrate 31, a
lower electrode 32, an orientation film 33, a light modulation layer 34, an
orientation film 35, an upper electrode 36, and a transparent substrate 37 are
arranged in order, starting from the reflector 4, for example, as illustrated in
FIG. 5. Here, an outer surface (opposite to a surface on which the upper
electrode 36 is disposed) of the transparent substrate 37 is adhered to the rear
surface of the light guiding plate 1. Incidentally, FIG. 5 is a sectional
diagram illustrating an example of a configuration of the light modulation
element 3.
[0057] The transparent substrates 31 and 37 are adapted to support the
light modulation layer 34 and are generally formed by substrates which are
transparent to visible light such as, for example, glass sheets, plastic films and
the like. The plurality of lower electrodes 32 are disposed on a surface of
the transparent substrate 31 which is opposite to the transparent substrate 37,
for example, as illustrated in FIG. 5 and FIG. 6. The plurality of lower
electrodes 32 are separated and insulated from one another. On the other
hand, the upper electrode 36 is disposed on a surface of the transparent
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substrate 37 which is opposite to the transparent substrate 31 and is formed by
a solid film which is so integrated as to oppose to all the plurality of lower
electrodes 32, for example, as illustrated in FIG. 5 and FIG. 6. Incidentally,
FIG. 6 is a perspective view illustrating an electrode structure of the light
modulation element 3. However, only the lower electrode 32, the light
modulation layer 34, and the upper electrode 36 are illustrated and other
constitutional elements of the light modulation element 3 are omitted in FIG. 6.
In addition, FIG. 6 illustrates a state viewed from the transparent substrate 31
for ready visual understanding of the shape and arrangement of the lower
electrodes 32.
[0058] The plurality of lower electrodes 32 are two-dimensionally arrayed
in a matrix along a surface of the transparent substrate 31, that is, on an XY
plane and each has a rectangular (or square) planar shape. The plurality of
lower electrodes 32 are connected with drive elements (not illustrated) such as,
for example, TFT elements which are embedded in the transparent substrate
31 in one-to-one correspondence so as to allow individual control of voltages
applied thereto. Each drive element is configured, for example, by using a
MOS-FET and, for example, its gate is connected to a gate line (not
illustrated) which extends in an X-axis direction, and its source is connected
to a data line (not illustrated) which extends in a Y-axis direction. The
backlight drive section 60 includes a voltage applying section which
selectively applies a predetermined voltage to each of the pluralities of gate
lines and data lines in accordance with the backlight control signal S2
supplied from the control section 40. In other words, the voltage applying
section applies a predetermined voltage, based on the backlight control signal
S2 supplied from the control section 40, between one or more selected from
the plurality of gate lines and one or more selected from the plurality of data
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lines. Therefore, the respective drive elements are allowed to be driven on
an individual basis by the backlight drive section 60. Thus, when
three-dimensional display is to be performed by the display device 100,
formation of various emission patterns is made possible by the backlight 30
and linear-shaped illumination light which extends in an arbitrary direction is
formed. While, when two-dimensional display is to be performed by the
display device 100, all the lower electrodes 32 are energized in order to
generate planar illumination light. Operations and the like of the above
mentioned elements will be described later.
[0059] Each of the lower electrodes 32 and the upper electrode 36 is made
of a transparent conductive material such as, for example, indium tin oxide
(ITO). However, the lower electrode 32 may be made of a material other
than a transparent material and may be made of, for example, metal.
Incidentally, if the lower electrode 32 is made of metal, the lower electrode 32
additionally has a function of reflecting light which is incident upon the light
modulation element 3 from behind the light guiding plate 1 similarly to the
reflector 4. Thus, in the latter case, the reflector 4 may be eliminated.
[0060] The light modulation cell 3S is formed in a region where each
lower electrode 32 is projected in a laminated direction (a Z-axis direction) of
the light modulation element 3, that is, a region where the lower electrodes 32
and the upper electrode 36 mutually superpose, for example, as illustrated by
broken lines in FIG. 5. Therefore, the plurality of light modulation cells 3S
are two-dimensionally arrayed in a matrix at predetermined intervals along the
XY plane in the light modulation element 3.
[0061 ] Each light modulation cell 3S is allowed to be separately and
independently driven by applying a predetermined voltage between a lower
electrode 32 concerned and the upper electrode 36. Specifically, each cell 3S
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exhibits transparency or scattering property to the light from the light source 2
in accordance with the magnitude of the voltage applied between the lower
electrode 32 and the upper electrode 36. Incidentally, the transparency and
scattering property will be described in detail later in explanation of the light
modulation layer 34.
[0062] The orientation films 33 and 35 are adapted to orient, for example,
a liquid crystal and a monomer used in the light modulation layer 34.
Although a vertical orientation film and a horizontal orientation film may be
given as examples of the kinds of orientation films, the horizontal orientation
films are used as the orientation films 33 and 35 in the first embodiment.
For example, an orientation film which is formed by rubbing polyimide,
polyamide imide, polyvinyl alcohol, and/or the like and an orientation film
which is grooved by transfer or etching may be given as examples of the
horizontal orientation film. For example, an orientation film which is
formed by obliquely depositing an inorganic material such as silicon oxide or
the like, a diamond-like carbon orientation film which is formed by ion beam
irradiation, and an orientation film in which an electrode pattern slit is formed
may be also given as examples of the horizontal orientation film. When
plastic films are used as the transparent substrates 31 and 37, it is preferable
that polyamide imide which may be formed at a temperature equal to or lower
than 100 degrees centigrade be used as the material of the orientation films 33
and 35 because it is desirable to reduce a firing temperature in a firing process
performed after the orientation films 33 and 35 have been applied onto the
surfaces of the transparent substrates 31 and 37 to a lowest possible value in a
manufacturing step.
[0063] It is good enough for both the vertical and horizontal orientation
films to have a function of orienting the liquid crystal and the monomer and
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reliability in repetitive application of the voltage which would be requested
for a normal liquid crystal display may not be requested because the reliability
in voltage application after producing a device is determined depending on an
interface between a monomer-polymerized material and a liquid crystal. The
liquid crystal and the monomer used in the light modulation layer 34 may be
also oriented, for example, by applying an electric field or a magnetic field
between the lower electrode 32 and the upper electrode 36, instead of using
the orientation film. That is, it is allowed to fix a state that the liquid crystal
and the monomer are oriented in a voltage-applied state by being irradiated
with ultraviolet rays, while applying the electric field or the magnetic field
between the lower electrode 32 and the upper electrode 36. When the
voltage is used for formation of orientation films, an electrode for orientation
may be formed separately from an electrode for driving, or a two-frequency
liquid crystal in which a dielectric anisotropy code is inverted depending on a
frequency may be used as a liquid crystal material. When a magnetic field is
used for formation of orientation films, it is preferable that a material which is
large in anisotropy of magnetic susceptibility be used as the orientation film
and it is preferable that a material, for example, having many benzene rings be
used as the orientation film.
[0064] The light modulation layer 34 exhibits scattering property or
transparency to light from the light source 20 in accordance with the
magnitude of an electric field applied. The light modulation layer 34 is a
composite layer which includes a bulk 34A and a plurality of fine particles
34B which are dispersed in the bulk 34A. The bulk 34A and the fine
particles 34B are optically anisotropic. In addition, the bulk 34A and the
fine particles 34B are different from each other in speed of response to the
electric field. The bulk 34A has, for example, a striped structure or a porous
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structure which does not respond to the electric field, or a rod-like structure
which is lower in speed of response than the fine particles 34B.
[0065] The bulk 34A is made by a polymer material which is obtained by
polymerizing, for example, a low molecular monomer. The bulk 34A is
formed by polymerizing an orientable and polymerizable material (for
example, a monomer) which is oriented, for example, in an oriented direction
of the fine particles 34B or in oriented directions of the orientation films 33
and 35 with at least one of heat and light. A striped structure, a porous
structure, or a rod-like structure of the bulk 34A has the major axis which is
directed, for example, to be parallel with the light incidence plane IA of the
light guiding plate 1 and to intersect the surfaces of the transparent substrates
31 and 37 at a small angle 01 (described later). When the bulk 34A has the
striped structure, it is preferable that a mean size of the striped structure in the
miner axis direction be equal to or more than 0.1 pm and equal to or less than
10 pin and it is more preferable that it be within a range from 0.2 pm or more
to 2.0 pm or less from the viewpoint of increasing the scattering property of
guided light. In addition, it is preferable that the mean size of the striped
structure in the miner axis direction be within a range from 0.5 pm or more to
5 pm or less and it is more preferable that it be within a range from 1 pm to 3
lmi from the viewpoint of reducing wavelength dependency of scattering.
The size of the striped structure may be observed through a polarization
microscope, a confocal microscope, an electron microscope or the like.
[0066] On the other hand, the fine particle 34B mainly contains, for
example, a liquid crystal material and has a sufficiently higher speed of
response than the bulk 34A. A liquid crystal material (a liquid crystal
molecule) contained in the fine particle 34B is, for example, a rod-like
molecule. It is preferable that a liquid crystal having the positive
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refractive-index anisotropy (a so-called positive liquid crystal) be used as the
liquid crystal molecule contained in the fine particle 34B.
[0067] FIG. 7A schematically illustrates an example of an orientation
state in the fine particle 34B when a voltage is not being applied between the
lower electrode 32 and the upper electrode 36. Incidentally, illustration of
the orientation state in the bulk 34A is omitted in FIG. 7A. FIG. 713
illustrates examples of index ellipsoids indicating refractive-index
anisotropies of the bulk 34A and the fine particle 34B when the voltage is not
being applied between the lower electrode 32 and the upper electrode 36.
The above mentioned index ellipsoid expresses the refractive index of linearly
polarized light which has been incident from various directions by a tensor
ellipsoid and the refractive index may be geometrically found by observing
the section of the ellipsoid from a light incident direction. FIG. 7C
schematically illustrates an example of a state that light L1 which directs in a
frontal direction and light L2 which directs in an oblique direction pass
through the light modulation layer 34 when the voltage is not being applied
between the lower electrode 32 and the upper electrode 36.
[0068] FIG. 8A schematically illustrates an example of the orientation
state in the fine particle 34B when a voltage is being applied between the
lower electrode 32 and the upper electrode 36. Incidentally, illustration of
the orientation state in the bulk 34A is omitted in FIG. 8A. FIG. 813
illustrates examples of index ellipsoids indicating refractive-index
anisotropies of the bulk 34A and the fine particle 34B when the voltage is
being applied between the lower electrode 32 and the upper electrode 36.
FIG. 8C schematically illustrates an example of a state that the light LI which
directs in a frontal direction and the light L2 which directs in an oblique
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direction are scattered in the light modulation layer 34 when the voltage is
being applied between the lower electrode 32 and the tipper electrode 36.
[0069] The bulk 34A and the fine particle 34B are configured such that
the orientation of an optical axis AX1 of the bulk 34A matches (is parallel
with) the orientation of an optical axis AX2 of the fine particle 34B when the
voltage is not being applied between the lower electrode 32 and the upper
electrode 36, for example, as illustrated in FIG. 7A and FIG. 7B. Incidentally,
the optical axes AX1 and AX2 indicate lines which run in parallel with a light
ray traveling direction in which the refractive index would have one value
regardless of a polarization direction of the light. Incidentally, the
orientations of the optical axes AX1 and AX2 need not typically match each
other and a slight deviation in orientation between the optical axes AXI and
AX2 is allowable depending on, for example, manufacturing errors.
[0070] The fine particle 34B is configured such that its optical axis AX2
is parallel with the light incidence plane 1A of the light guiding plate 1, for
example, when the voltage is not being applied between the lower electrode
32 and the upper electrode 36. The fine particle 34B is also configured such
that its optical axis AX2 intersects the surfaces of the transparent substrates
31 and 37 at the small angle 01, for example, when the voltage is not being
applied between the lower electrode 32 and the upper electrode 36 (see FIG.
7B). Incidentally, the angle 01 will be described in detail in explanation of
the material of the fine particle 34B.
[0071] On the other hand, the bulk 34A is configured such that its optical
axis AX1 is maintained constant regardless of, for example, whether the
voltage is being applied between the lower electrode 32 and the upper
electrode 36. Specifically, the bulk 34A is configured such that its optical
axis AX1 is parallel with the light incidence plane lA of the light guiding
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plate I and intersects the surfaces of the transparent substrates 31 and 37 at
the predetermined angle 01, for example, as illustrated in FIG. 7A, FIG. 7B,
FIG. 8A, and FIG. 813. That is, the optical axis AXI of the bulk 34a is
parallel with the optical axis AX2 of the fine particle 34B when the voltage is
not being applied between the lower electrode 32 and the upper electrode 36.
[0072] Incidentally, the optical axis AX2 need not typically be parallel
with the light incidence plane 1 A of the light guiding plate I and intersect the
surfaces of the transparent substrates 31 and 37 at the angle 01, and the optical
axis AX2 may intersect the surfaces of the transparent substrates 31 and 37 at
an angle which is slightly different from the angle 01 depending on, for
example, manufacturing errors. Similarly, the optical axes AX1 and AX2
need not typically be parallel with the light incidence plane IA of the light
guiding plate 1 and may have a small angle relative to the light incidence
plane IA of the light guiding plate 1 depending on, for example,
manufacturing errors.
[0073] Here, it is preferable that the refractive index of ordinary ray of
the bulk 34A be equal to that of the fine particle 34B and the refractive index
of extraordinary ray of the bulk 34A be equal to that of the fine particle 34B.
In the above mentioned case, almost no difference in refractive index is
observed in all directions including frontal and oblique directions and a high
transparency is obtained as illustrated in FIG. 7A, for example, when the
voltage is not being applied between the lower electrode 32 and the upper
electrode 36. Therefore, the front-wise directed light L1 and the obliquely
directed light L2 pass through the light modulation layer 34 without being
scattered in the light modulation layer 34, for example, as illustrated in FIG.
7C. As a result, light L (obliquely directed light) from the light source 2 is
totally reflected at an interface (an interface between the transparent substrate
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31 and the light guiding plate 1, and air) of the transparent region 3A, for
example, as illustrated in (A) and (B) of FIG. 9 and the luminance (the
luminance of a black-displayed part) of the transparent region 3A is reduced
in comparison with a case that the light modulation element 3 is not included
(a one-point chain line in (B) of FIG. 9).
[0074] The bulk 34A and the fine particle 34B are configured such that
the orientation of the optical axis AX1 of the bulk 34A is different from
(intersects) the orientation of the optical axis AX2 of the fine particle 34B as
illustrated in FIG. 8B, for example, when the voltage is being applied between
the lower electrode 32 and the upper electrode 36. In addition, the fine
particle 34B is configured such that its optical axis AX2 is parallel with the
light incidence plane IA of the light guiding plate 1 and intersects the surfaces
of the transparent substrates 31 and 37 at an angle 02 (for example, 90
degrees) which is larger than the angle 01, for example, when the voltage is
being applied between the lower electrode 32 and the upper electrode 36.
Incidentally, the angle 02 will be described in detail in explanation of the
material of the fine particle 34B.
[0075] Therefore, a difference in refractive index is increased in all
directions including the frontal and oblique directions in the light modulation
layer 34 and hence a high scattering property is obtained when the voltage is
being applied between the lower electrode 32 and the upper electrode 36.
Thus, the front-wise directed light L1 and the obliquely directed light L2 are
scattered in the light modulation layer 34, for example, as illustrated in FIG.
8C. As a result, the light L (obliquely directed light) from the light source 2
passes through an interface (an interface between the transparent substrate 31
and the light guiding plate 1, and air) of the scattering region 3B and the light
which has passed toward the reflector 4 is reflected by the reflector 4 and
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passes through the light modulation element 3, for example, as illustrated in
(A) of FIG. 9. Therefore, the luminance of the scattering region 3B is greatly
increased in comparison with the case that the light modulation element 3 is
not included (the one-point chain line in (B) of FIG. 9) and the luminance
(pushing-up of luminance) of a partially white-displayed part is increased by
the amount corresponding to a reduction in luminance of the transparent
region 3A.
[0076] Although a slight deviation in refractive index of ordinary ray
between the bulk 34A and the fine particle 34B is allowable depending on, for
example, manufacturing errors, it is preferable that the deviation be, for
example, equal to or less than 0.1 and it is more preferable that the deviation
be equal to or less than 0.05. Similarly, although a slight deviation in
refractive index of extraordinary ray between the bulk 34A and the fine
particle 34B is allowable depending on, for example, manufacturing errors, it
is preferable that the deviation be, for example, equal to or less than 0.1 and it
is more preferable that the deviation be equal to or less than 0.05.
[0077] It is preferable that a refractive index difference (Anp = refractive
index of extraordinary ray n,p - refractive index of ordinary ray nop) of the
bulk 34A and a refractive index difference (AnL = refractive index of
extraordinary ray n1L - refractive index of ordinary ray noL) of the fine
particle 34B be as large as possible. It is preferable that the differences be
equal to or more than 0.05, it is more preferable that the differences be equal
to or more than 0.1, and it is still more preferable that the differences be equal
to or more than 0.15 because when the refractive index differences of the bulk
34A and the fine particle 34B are large, the scattering power of the light
modulation layer 34 is increased and hence ready breaking of light guiding
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conditions and ready taking-out of light from the light guiding plate I are
allowed.
[0078] Here, the major-axis direction of the liquid crystal molecule is
parallel with the optical axis AX2 in the fine particle 34B when the voltage is
not being applied between the lower electrode 32 and the upper electrode 36.
In the above mentioned case, the major axis of the liquid crystal molecule in
the fine particle 34B is parallel with the light incidence plane IA of the light
guiding plate 1 and defines the small angle 01 relative to the surfaces of the
transparent substrates 31 and 37. That is, the liquid crystal molecule in the
fine particle 43B is oriented in a state that its major axis tilts by the angle 01
in a plane which is parallel with the light incidence plane IA of the light
guiding plate when the voltage is not being applied between the lower
electrodes 32 and the upper electrode 36. The angle 01 is a so-called pre-tilt
angle. It is preferable that the angle 01 be, for example, within a range from
0.1 degrees or more to 30 degrees or less, it is more preferable that it be
within a range from 0.5 degrees or more to 10 degrees or less, and it is still
more preferable that it be within a range from 0.7 degrees or more to 2
degrees or less. If the angle 01 is increased, the scattering efficiency may be
liable to be reduced for reasons which will be described later. If the angle 01
is reduced too much, the azimuth angle at which the liquid crystal builds up
may be varied when the voltage is applied. In some cases, the liquid crystal
may build up in a 180 degree-reversed orientation (a reverse tilt). Therefore,
since effective utilization of the refractive index differences of the fine
particle 34B and the bulk 34A is not allowed, the scattering efficiency may be
liable to be reduced to reduce the luminance.
[0079] The major-axis direction of the liquid crystal molecule intersects
(or is orthogonal to) the optical axis AX2 in the fine particle 34B when the
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voltage is being applied between the lower electrode 32 and the tipper
electrode 36. At that time, the major axis of the liquid crystal molecule in
the fine particle 34B is parallel with the light incidence plane lA of the light
guiding plate 1 and defines the angle 02 (for example, 90 degrees) which is
larger than the angle 01 relative to the surfaces of the transparent substrates
31 and 37. That is, the liquid crystal molecule in the fine particle 34B is
oriented in a state that its major axis tilts at the angle 02 in a plane which is
parallel with the light incidence plane IA of the light guiding plate 1 when the
voltage is being applied between the lower electrode 32 and the upper
electrode 36.
[0080] Although any material may be used as the above mentioned
orientable and polymerizable monomer which configures the bulk 34A as long
as it is a material which is optically anisotropic and is compounded with a
liquid crystal, it is preferable that the material be an ultraviolet-curable low
molecular monomer in the first embodiment. Since it is preferable that it
match a material (a polymer material) which is formed by polymerizing a
liquid crystal and a low molecular monomer in direction of optical anisotropy
in a state that no voltage is applied, it is preferable that the liquid crystal and
the low molecular monomer be oriented in the same direction before it is
cured with ultraviolet rays. It is preferable that a monomer material used be
a rod-shaped one when a liquid crystal is used as the fine particle 34B and the
liquid crystal is a rod-shaped molecule. Under the circumstances, it is
preferable that a material having both polymerizability and liquid crystallinity
be used as the monomer material, and it is preferable that it have at least one
functional group which is selected from a group including, for example, an
acrylate group, a methacrylate group, an acryloyloxy group, a
methacryloyloxy group, a vinyl ether group, and an epoxy group as a
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polymeric functional group. These functional groups may be polymerized by
being irradiated with ultraviolet rays, infrared rays, or electron beams, or by
being heated. A liquid -crystal line material having a multifunctional group
may be added to the above in order to suppress a reduction in orientability
when irradiated with ultraviolet rays. It is referable that a two-functional
liquid-crystalline monomer be used as the raw material of the bulk 34A when
the bulk 34A has the above mentioned striped structure. In addition, a
mono-functional monomer may be added to the raw material of the bulk 34A
in order to adjust the temperature at which liquid-crystallinity exhibits or
monomers having three or more functional groups may be added thereto in
order to improve crosslinking density.
[0081] The backlight drive section 60 is configured to control the
magnitude of the voltage to be applied between a pair of electrodes (the lower
electrode 32 and the upper electrode 36) of each light modulation cell 3S such
that, for example, the optical axis AX2 of the fine particle 34B is parallel or
almost parallel with the optical axis AX1 of the bulk 34A in one light
modulation cell 3S and the optical axis AX2 of the fine particle 34B intersects
or is orthogonal to the optical axis AX1 of the bulk 34A in another light
modulation cell 3S. That is, the backlight drive section 60 is configured to
make the orientations of the optical axes AX1 and AX2 of the bulk 34A and
the fine particle 34B match (almost match) each other or to make them
different from (or orthogonal to) each other by controlling an electric field to
be applied.
[0082] The backlight drive section 60 is configured to output a plurality
of rays of linear-shaped illumination light from the backlight 30 when a signal
for instructing three-dimensional display has been input as the backlight
control signal S2. Specifically, the backlight drive section 60 is configured
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to apply a voltage at which the light modulation layer 34 would exhibit
scattering property to a plurality of specific lower electrodes 32 and to apply a
voltage at which the light modulation layer 34 would exhibit transparency to
remaining lower electrodes 32. In other words, the backlight drive section
60 controls the magnitude of the voltage to be applied between each lower
electrode 32 and the upper electrode 36 such that the optical axis AX2 of the
fine particle 34B intersects the optical axis AX1 of the bulk 34A in each of the
plurality of selected light modulation cells 3S. At the same time, the
backlight drive section 60 controls the magnitude of the voltage to be applied
between each lower electrode 32 and the upper electrode 36 such that the
optical axis AX2 of the fine particle 34B is parallel with the optical axis AX1
of the bulk 34A in each of all the remaining unselected light modulation cells
3S.
[0083] The backlight drive section 60 is also configured to output planar
illumination light from the backlight 30 when a signal for instructing
two-dimensional display has been input as the backlight control signal S2.
Specifically, the backlight drive section 60 is configured to apply a voltage at
which the light modulation layer 34 would exhibit scattering property to all
the plurality of lower electrodes 32. In other words, the backlight drive
section 60 controls the magnitude of the voltage to be applied between each
lower electrode 32 and the upper electrode 36 such that the optical axis AX2
of the fine particle 34B intersects the optical axis AXI of the bulk 34A in each
of all the light modulation cells 3S included in the light modulation element 3.
[Display Method]
[0084] Next, a method of displaying a stereoscopic image using the
display device 100 according to the first embodiment will be described. The
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operation and effect of the display device 100 will be described in addition to
the above.
[0085] First, the attitude of the display device 100 relative to a viewer is
detected when three-dimensional display (stereoscopic image display) is to be
performed by the display device 100. Specifically, to which directions
horizontal (lateral) and vertical directions for the viewer correspond is
determined by the control section 40 by detecting the positions of, for
example, of the viewer's left and right eyes by the sensor section 10. Next, a
plurality of perspective images which are obtained according to the attitude of
the display device 100 are displayed all together on the display section 20 on
the basis of the image signal Si. An emission pattern corresponding to the
attitude of the display device 100 is formed by separately driving the plurality
of light modulation cells 3S in synchronization with the above.
[0086 ] In the backlight 30, a voltage is applied between a pair of
electrodes (the lower electrode 32 and the upper electrode 36) such that the
optical axis AX2 of the fine particle 34B tilts in a direction which is different
from that of the optical axis AX1 of the bulk 34A in a selected light
modulation cell 3S. Thus, the selected light modulation cell 3S serves as the
scattering region 3B and other (unselected) light modulation cells 3S serve as
the transparent (transmitting) regions 3A in the light modulation element 3.
As a result, light which has been radiated from the light source 2 and incident
upon the light guiding plate 1 passes through the transparent region 3A and is
scattered in the scattering region 3B (see (A) of FIG. 9). Light which is
included in the scattered light and has passed through a lower surface of the
scattering region 3B is reflected by the reflector 4, is again returned to the
light guiding plate 1, and is radiated from an upper surface of the backlight 30.
While, light which is included in the scattered light and has be directed
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toward an upper surface of the scattering region 3B passes through the light
guiding plate 1 and is radiated from the upper surface thereof (that is, the
upper surface of the backlight 30) (see (A) of FIG. 9). In three-dimensional
display, light is hardly radiated from the upper surface of the transparent
region 3A and is radiated from the upper surface of the scattering region 3B as
described above. Flere, when it has been determined that the horizontal
direction for the viewer corresponds to the X-axis direction on the basis of
information sent from the sensor section 10, a voltage is applied only to lower
electrodes 32 included in a line LY2 of lines LYI to LY4, each including lower
electrodes 32 which are arrayed one after another in the Y-axis direction, for
example, as illustrated in FIG. 10. Then, each light modulation cell 3S which
includes the lower electrodes 32 included in the line LY2 serves as each
scattering region 3B. In the above mentioned situation, since a space
between adjacent lower electrodes 32 is narrow, rays of radiated light
(scattered light) from the respective scattering regions 3B are substantially
connected one after another in the Y-axis direction. Thus, a plurality of
linear-shaped emission patterns 30PA, each extending in the Y-axis direction,
are formed to be arrayed at predetermined intervals in the X-axis direction by
the plurality of scattering regions 3B which are located one after another in
the Y-axis direction, for example, as illustrated in FIG. 11. The emission
patterns 30PA correspond to arrangement positions of the selected lower
electrodes 32. As a result, a plurality of rays of linear-shaped illumination
light LA which extend in the Y-axis direction are output toward the display
section 20. It is to be noted that intervals at which the emission patterns
30PA are arranged may be appropriately selected depending on the size and
arrangement state of each pixel included in the display section 20 and/or the
number of perspectives.
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[0087] Each ray of linear-shaped illumination light LA which has been
output from the backlight 30 is incident upon a rear surface of the display
section 20, for example, as illustrated in FIG. 12. Here, it is supposed that,
for example, four perspective images (first to four perspective images) are to
be displayed all together on the display section 20. In the above mentioned
case, pixels PXI to PX4 which are repetitively and sequentially arrayed in the
X-axis direction display the respective first to four perspective images.
Although the rays of linear-shaped illumination light LA from the respective
scattering regions 3B are incident upon the pixels P1 to P4 which are
repetitively and sequentially arrayed in the X-axis direction, the positions of
the respective pixels PX1 to PX4 relative to the respective scattering regions
3B are maintained constant over the entire surface of the display device 100.
That is, for example, the rays of linear-shaped illumination light LA from the
scattering regions 3B are incident upon all the pixels PX1 on the display
section 20 substantially at the same angle. This also applies to the pixels
PX2 to PX4. As a result, rays of image light which have been respectively
modulated therein are output from the respective pixels PXI to PX4 at
predetermined angles. Since the viewer observes mutually different
perspective images with his/her left and right eyes, the viewer recognizes that
a three-dimensional image (a stereoscopic image) is being displayed on the
display section 20. Incidentally, the number of perspectives is not limited to
four and any number of perspectives may be set.
[0088] As an alternative, for example, two kinds of image signals may be
alternately supplied to the display drive section 50 so as to alternately display
two kinds of images in time division on the display section 20 on the basis of
the two kinds of image signals when a stereoscopic image is to be displayed in
the display device 100. In the above mentioned case, it is desirable for the
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backlight 30 to successively form two kinds of emission patterns 30PA in
synchronization with time-divided image display. It becomes possible to
increase the resolution of the stereoscopic image by performing time-divided
image display as mentioned above.
[0089] On the other hand, a voltage is applied between the upper
electrode 36 and the lower electrodes 32 included in all the light modulation
cells 3S when a two-dimensional image is to be displayed. Thus, all the light
modulation cells 3S serve as the scattering regions 3B. As a result, light
which has been radiated from the light source 2 and incident upon the light
guiding plate 1 is scattered in the scattering region or reflected by the
reflector 4 and is planarly radiated from the entire upper surface of the
backlight 30. That is, planar illumination light L (described later) is output
from the backlight 30 toward the display section 20.
[0090] The planar illumination light L which has been output from the
backlight 30 is incident upon the rear surface of the display section 20, for
example, as illustrated in FIG. 13. At that time, a single perspective image
for two-dimensional image display is displayed on the display section 20.
Rays of planar illumination light LO are incident upon the respective pixels
Pix at all possible angles and rays of image light which have been modulated
in the respective pixels are output from the pixels Pis. Since the viewer
observes the same image with his/her both eyes, the viewer recognizes that a
two-dimensional image (a planar image) is being displayed on the display
section 20.
[0091 ] Incidentally, it is possible to form an arbitrary emission pattern in
accordance with the attitude of the display device 100 relative to the viewer
by appropriately selecting the light modulation cell 3S to be used as the
scattering region 3B in the backlight 30 of the first embodiment. That is, it
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is possible to generate linear-shaped illumination light which extends in an
arbitrary direction.
[0092] Here, a case in which it has been determined that, for example, the
horizontal direction for the viewer corresponds to the Y-axis direction on the
basis of information from the sensor section 10 will be described. In the
above mentioned case, in the backlight 30, a voltage is applied only to the
lower electrodes 32 included, for example, in a line LX2 of lines LXI to LX4,
each including the lower electrodes 32 which are located one after another in
the X-axis direction, for example, as illustrated in FIG. 14. Then, each light
modulation cell 3S which includes the lower electrodes 32 included in the line
LX2 serves as the scattering region 3B. In this situation, since a space
between adjacent lower electrodes 32 is narrow, rays of radiated light
(scattered light rays) from the respective scattering regions 3B are
substantially connected one after another in the X-axis direction. Thus, a
plurality of linear-shaped emission patterns 30PB which extend in the X-axis
direction are formed to be arrayed at predetermined intervals in the X-axis
direction by the plurality of scattering regions 3B which are located one after
another in the X-axis direction in the backlight 30, for example, as illustrated
in FIG. 15. The emission pattern 30PB corresponds to the arrangement
position of the selected lower electrodes 32. As a result, a plurality of rays
of linear-shaped illumination light LB which extend in the X-axis direction
are output toward the display section 20. Pixels PYI to PY4 which are
repetitively and sequentially arrayed in the Y-axis direction display all
together first to fourth perspective images on the display section 20 upon
which the rays of linear-shaped illumination light LB are incident, for
example, as illustrated in FIG. 16. Rays of image light which have been
respectively modulated in the pixels are output from the pixels PYI to PY4 at
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predetermined angles. Since the viewer observes mutually different
perspective images with his/her left and right eyes, the viewer recognizes that
a three-dimensional image (a stereoscopic image) is being displayed on the
display section 20. It is to be noted that also in the above mentioned case,
the number of perspectives is not limited to four and any number of
perspectives may be set.
[0093] For example, when the horizontal direction for the viewer has been
determined to correspond to a 45 degree-tilted direction (an oblique direction)
relative to both the X-axis and Y-axis on the basis of information sent from
the sensor section 10, operation as follows may be performed. That is, in the
backlight 30, a voltage is applied to only the lower electrodes 32, for example,
included in a line LXY2 of lines LXY1 to LXY4, each including the lower
electrodes 32 which are located one after another in the oblique direction, for
example, as illustrated in FIG. 17. Then, each light modulation cell 3S
including the lower electrodes 32 in the line LXY2 serves as each scattering
region 3B. Thus, in the backlight 30, a plurality of linear-shaped emission
patterns which extend in the oblique direction are formed by the plurality of
scattering regions 3B which are arrayed one after another in the oblique
direction. As a result, a plurality of rays of linear-shaped illumination light
which extend in the oblique direction are output toward the display section 20.
A plurality of perspective images are displayed all together by pixels which
are sequentially and repetitively arrayed in a direction intersecting a direction
in which the rays of linear-shaped illumination light extend on the display
section 20. Therefore, it becomes possible for the viewer to observe
mutually different perspective images with his/her left and right eyes and to
recognize that a stereoscopic image is being displayed on the display section
20.
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[0094] According to the backlight 30 of the first embodiment, it is
possible to form the emission patterns in which the plurality of light
modulation cells 3S which are located one after another like a strip in the
same direction are arrayed at predetermined intervals and to generate the
plurality of rays of linear-shaped illumination light as described above. Thus,
according the display device 100 which includes the backlight 30, it becomes
possible to make images that the viewer recognizes with his/her left and right
eyes different from each other in accordance with a relative positional relation
(angle) among each of the emission patterns, the display section 20, and each
of perspective positions of the viewer's left and right eyes. As a result, it
becomes possible for the viewer to recognize a stereoscopic image. Here,
since a direction in which the rays of linear-shaped illumination light extend
may be arbitrarily set, it is possible to address a change in correlation between
the display section and each of the perspective positions of the viewer's left
and right eyes. That is, since the attitude of the display device relative to the
viewer is detected by the sensor section 10, and emission patterns of the
backlight 30 are formed and perspective images are displayed in accordance
with a result of detection, it becomes possible for the viewer to recognize a
favorable stereoscopic image even when the display device 100 is rotated in
an arbitrary direction. Since an arbitrary emission pattern may be formed at
an arbitrary timing, it is possible to handle time division display on the
display section 20. Incidentally, it is desirable that a direction in which
linear-shaped illumination light extends be different from a direction in which
the pixels Pix (color filters) of the display section 20 are arrayed in order to
avoid generation of moire in stereoscopic image display. Thus, the lower
electrodes 32 may be arrayed in a direction (an oblique direction) intersecting
the X-axis direction and the Y-axis direction, for example, when the pixels Pix
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(the color filters) of the display section 20 are arrayed in a matrix in the
X-axis and Y-axis directions. As a result, it becomes possible to obtain the
linear-shaped illumination light which extends in a direction intersecting a
direction in which the pixels Pix (the color filters) are arrayed to avoid
generation of moire.
[0095] Also, since three-dimensional display is attained with no
installation of a parallax barrier in the first embodiment, it is possible to
utilize light from the light source 2 as the linear-shaped illumination light
more efficiently than would be possible when the parallax barrier is used. In
addition, since three-dimensional display is attained with no installation of a
cylindrical lens in the first embodiment, a disadvantage of occurrence of an
aberration caused by the cylindrical lens is avoided. Further, since neither
the parallax barrier nor the cylindrical lens is used, it is possible to further
simplify the general configuration.
[Modification]
[0096] The first embodiment is configured such that the drive element is
disposed for every light modulation cell 3S and the respective light
modulation cell 3S are active-matrix-driven to form the transparent region 3A
and the scattering region 313. On the other hand, the present modification
includes a light modulation element 5 which is configured to form the
transparent region 3A and the scattering region 3B by passive-matrix-driving
the respective light modulation cells 3S. FIG. 18 illustrates a perspective
configuration of essential parts of the light modulation element 5 according to
the present modification. The light modulation element 5 is configured in
the same manner as the light modulation element 3 excepting a point that a
lower electrode 42 and an upper electrode 46 are disposed in place of the
lower electrodes 32 and the upper electrode 36. The lower electrode 42 and
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the upper electrode 46 are configured as, for example, strip electrodes which
are rectangular in plane, and plural lower electrodes and upper electrodes are
disposed. The plurality of lower electrodes 42 are arranged, for example, so
as to extend in the X-axis direction and to be arrayed in the Y-axis direction.
While, the plurality of tipper electrodes 46 are arranged, for example, so as to
extend in the Y-axis direction and to be arrayed in the X-axis direction. In
the light modulation element 5, each region where the lower electrode 42
intersects the upper electrode 46 defines the light modulation cell 3S. Thus,
it is possible to make a desired light modulation cell 3S serve as the scattering
region 3B by selecting a predetermined lower electrode 42 and a
predetermined upper electrode 46 and applying a voltage between them.
Therefore, the same effect as that of the first embodiment is obtained by the
modification. In addition, since a necessity of providing a drive element for
every light modulation cell 3S may be eliminated, it is possible to simplify the
configuration of a drive circuit in the light modulation element 5.
Incidentally, directions in which the lower electrodes 42 and the upper
electrodes 46 extend are not limited to mutually orthogonal directions and
may be arbitrarily selected. However, it is desirable that a direction in which
the light modulation cells 3S are arrayed be made different from a direction in
which the pixels Pix (the color filters) of the display section 20 are arrayed in
order to avoid generation of moire in stereoscopic image display. Thus, the
lower electrodes 42 and the upper electrodes 46 may be extended in directions
(oblique directions) respectively intersecting both the X-axis direction and the
Y-axis directions, for example, when the pixels Pix (the color filters) of the
display section 20 are arrayed in a matrix in the X-axis and Y-axis directions.
As a result, it becomes possible to obtain linear-shaped illumination light
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which extends in a direction intersecting a direction in which the pixels Pix
(the color filters) are arrayed to avoid generation of moire.
[Second Embodiment]
[0097 ] Next, a second embodiment of the present disclosure will be
described in detail with reference to the accompanying drawings.
Description has been made by illustrating the backlight 30 which includes the
light modulation element 3 or 5 utilizing the PDLC as the lighting unit in the
first embodiment. On the other hand, the display device according to the
second embodiment is of the type that electronic paper 7 which includes an
electrophoresis element, for example, as illustrated in FIG. 19 in the backlight
30 as the lighting unit, in place of the light modulation element 3 or 5. The
display device according to the second embodiment is configured in the same
manner as the display device 100 excepting a point that the electronic paper 7
is used. Thus, in the following, the electronic paper 7 will be described.
[Configuration of Electronic Paper]
[0098 ] The electronic paper 7 is of the type that a drive substrate 71 and a
counter substrate 72 are arranged in opposition via an electrophoresis element
layer 73 which includes a plurality of microcapsules 73A. In the electronic
paper 7, illumination light is radiated from the counter substrate 72.
[0099] The drive substrate 71 is of the type that, for example, a wiring
layer 712 which includes mutually stereoscopically intersecting plural signal
lines and scanning lines (not illustrated), a semiconductor layer 713 which
includes a drive element (not illustrated) such as a TFT element or the like,
and a plurality of pixel electrodes 714 are formed in this order on a surface of
a support base 711. The drive elements (TFTs) and the pixel electrodes 714
are arranged in a matrix corresponding to, for example, the arrangement of the
pixels Pix (see FIG. 2) of the display section 20.
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[0100 ] The support base 711 is made of, for example, an inorganic
material, a metallic material, a plastic material and/or the like. The
inorganic material includes, for example, silicon (Si), silicon oxide (SiO,),
silicon nitride (SiNx), aluminum oxide (AIO,), and/or the like. The silicon
oxide includes glass, spin-on-glass (SOG) and/or the like. The metallic
material includes, for example, aluminum (Al), nickel (Ni), stainless steel,
and/or the like. The plastic material includes, for example, polycarbonate
(PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN),
polyether ether ketone (PEEK), and/or the like.
[0101 ] The support base 711 may be either light-permeable or
light-impermeable, because illumination light is radiated from the counter
substrate 72. In addition, the support base 711 may be a rigid substrate such
as a wafer or a flexible thin-layer glass sheet or film.
[0102] The drive element is a switching element for selecting a pixel.
The signal lines and the scanning lines, and the drive elements are embedded
in the wiring layer 712 and the semiconductor layer 713, for example, with
insulating resin materials such as polyimide and the like.
[0103 ] The pixel electrode 714 is made of various conductive materials
such as, for example, metallic materials such as gold (Au), silver (Ag), and/or
copper (Cu), compounds such as indium tin oxide (ITO) and/or the like, or
other alloys. The pixel electrode 714 is connected with the drive element
through a contact hole (not illustrated) which is formed, for example, in the
semiconductor layer 713.
[0104] The counter substrate 72 is of the type that, for example, a counter
electrode 722 is formed over one surface of a support base 721. That is, the
counter electrode 722 is a common electrode which is commonly prepared for
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the plurality of pixels. Alternatively, the counter electrode 722 may be
arranged in a strip-form.
[0105] The support base 721 is made of the same material as the support
base 711 excepting a point that it is light-permeable. The counter electrode
722 is made of a translucent conductive material (a transparent electrode
material) such as, for example, indium tin oxide (ITO), antimony tin oxide
(ATO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO)
and/or the like. The support base 721 is in contact with the light guiding
plate 1 (see FIG. 4) and is made of a material which is the same as that of the
light guiding plate 1 in refractive index in order to ensure light-guiding
property. As an alternative, the light guiding plate 1 may be also used as the
support base 721.
[0106] The electrophoresis element layer 73 is of the type that, for
example, the plurality of the microcapsules 73A into which electrophoresis
elements 74 are sealed are densely arrayed and is disposed between the drive
substrate 71 and the counter substrate 72. Incidentally, the number of the
microcapsules 73A need not necessarily be the same as the number of the
pixel electrodes 714. The electrophoresis element 74 is adapted to create
contrast by utilizing an electrophoresis phenomenon and contains an
insulating liquid 75 and a plurality of electrophoresis particles 76.
[0107] The insulating liquid 75 contains, for example, one, two or more
kinds of organic solvents such as paraffin and/or iso-paraffin specifically. It
is preferable that the viscosity and refractive index of the insulating liquid 75
be as low as possible because the mobility (speed of response) of the
electrophoresis particle 76 is improved and energy (power consumption) used
to move the electrophoresis particles 76 is reduced accordingly.
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[0108] Incidentally, the insulating liquid 75 may contain various
materials on an as-needed basis. For example, a coloring agent, a charge
controlling agent, a dispersion stabilizer, a viscosity improver, a surfactant
and/or resin may be given as examples of the materials.
[0109] The electrophoresis particle 76 is a charged particle dispersed in
the insulating liquid 75 and is movable within the microcapsule 73A in
accordance with an electric field applied. The electrophoresis particle 76
contains one, two or more kinds of particles (powder) of, for example, an
organic pigment, an inorganic pigment, a dye, a carbon material, a metallic
material, a metal oxide, glass, a high polymer material (resin), and/or the like.
As an alternative, the clectrophoresis particle 76 may be a ground particle or
an encapsulated particle on a solid basis of resin containing the above
mentioned particles. It is to be noted that materials corresponding to the
carbon material, the metallic material, the metal oxide, the glass, the high
polymer material, and/or the like are excluded from the materials
corresponding to the organic pigment, the inorganic pigment, the dye, and/or
the like.
[0110] The organic pigment includes, for example, azo pigments, metal
complex azo pigments, azo poly-condensation pigments, flavanthrone
pigments, benzimidazolone pigments, phthalocyanine pigments, quinacridone
pigments, anthraquinone pigments, perylene pigments, perinone pigments,
anthrapyridine pigments, pyranthrone pigments, dioxazine pigments,
thioindigoid pigments, isoindolinone pigments, quinophthalone pigments,
indanthrene pigments, and/or the like. The inorganic pigment includes, for
example, zinc oxide, antimony white, carbon black, iron black, titanium
boride, bengala (iron oxide red), mapicoyellow, lead tetroxide,
cadomiumyellow, zinc sulfide, lithopone, barium sulfide, cadomium selenide,
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calcium carbonate, barium sulfate, chromium zinc oxide, lead sulfate, barium
carbonate, white lead, alumina white, and/or the like. The dye includes, for
example, nigrosine dyes, azo dyes, phthalocyanine dyes, quinophthalone dyes,
anthrachinon dyes, methine dyes, and/or the like. The carbon material
includes, for example, carbon black and/or the like. The metallic material
includes, for example, gold, silver, copper and/or the like. The metal oxide
includes, for example, titanium oxide, zinc oxide, zirconium oxide, barium
titanate, potassium titanate, and/or the like. The high polymer material
includes, for example, high polymer compounds into which a functional group
having a light absorption region in a visible light region is introduced. No
limitation is set on the kind of the high polymer compound as long as it is of
the type having the light absorption region in the visible light region.
[0111] White or almost white color is preferable as the color of the
electrophoresis particle 76 in order to increase the intensity of light reflected
from the electrophoresis particle 76 by effectively inducing scattering of
visible light with the electrophoresis particle 76, thereby obtaining brighter
illumination light. Thus, metal oxide such as, for example, titanium oxide,
zinc oxide, zirconium oxide, barium titanate, potassium titanate, and/or the
like are preferable as the specific constitutional material of the
electrophoresis particle 76.
[0112] Incidentally, it is preferable that the electrophoresis particle 76 be
liable to be dispersed and charged over a long period of time in the insulating
liquid 75. Thus, a dispersing agent (a charge modifier) may be used in order
to make the electrophoresis particle 76 disperse by electrostatic repulsion,
surface treatment may be performed on the electrophoresis particle 76, or both
of them may be adopted simultaneously.
[Operation and Effect of Electronic Paper]
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[0113] In the electronic paper 7, the plurality of electrophoresis particles
76 are located at positions separated from the counter substrate 72 in their
initial state, for example, as illustrated in FIG. 19. In the above mentioned
case, no contrast is created (no reflected light is generated) when observing
the electrophoresis element layer 73 from the counter substrate 72.
[0114] When a voltage is applied between the counter electrode 722 and a
predetermined pixel electrode 714 which has been selected by the drive
element and an electric field is generated between the electrodes, the
electrophoresis particle 76 which is present in a region where the electric field
is generated moves to the vicinity of the counter electrode 722, for example,
as illustrated in FIG. 20. As a result, the electrophoresis particles 76 which
are present away from the counter substrate 72 and the electrophoresis
particles 76 which are present in the vicinity of the counter substrate 72
coexist in the electrophoresis element layer 73. As a result, such a state is
obtained that the contrast is created when observing the electrophoresis
particles 73 from the counter substrate 72. That is, since light which has
been incident upon the electrophoresis element layer 73 through the light
guiding plate I is reflected and scattered by the electrophoresis particles 76
which have moved to the vicinity of the counter electrode 722, that region
serves as a scattering region 7B and the luminance of the region is more
increased than a region (a non-scattering region 7A) other than the above.
Thus, it becomes possible for the electronic paper 7 to form an arbitrary
emission pattern in a plane. Owing to the above, it becomes possible to
output, for example, linear-shaped illumination light so as to direct toward the
display section 20 also in the backlight 30 in which the electronic paper 7 is
used. Thus, the second embodiment attains the same effect as the first
embodiment. Incidentally, if a black particle such as, for example, carbon
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black is used as the electrophoresis particle 76, incident light may be partially
absorbed by the particle and the intensity of reflected light may be more
reduced than would be reduced when a white particle is used. Therefore,
efficient utilization of light energy of the light source 2 is possible by using a
white particle as the electrophoresis particle 76.
[0115] Although the second embodiment is configured such that the drive
elements are disposed respectively for the plurality of pixel electrodes 714
which are arranged in a matrix so as to active-matrix-drive the electrophoresis
element layer 73, an arbitrary emission pattern may be formed by
passive-matrix-driving the electrophoresis element layer 73.
[Third Embodiment]
[0116] Next, a third embodiment of present disclosure will be described
in detail with reference to the accompanying drawings. In the first
embodiment, description has been made by illustrating the backlight 30 which
includes the light modulation element 3 or 5 utilizing the PDLC as the lighting
unit. On the other hand, a display device according to the third embodiment
is of the type that a backlight 8 which includes an organic light emitting
element 80 illustrated, for example, in FIG. 21 is used in place of the
backlight 30 as the lighting unit. FIG. 21 is an enlarged sectional diagram
illustrating essential parts of the backlight 8. The display device according
to the third embodiment is configured in the same manner as the display
device 100 excepting a point that the backlight 8 is used. Thus, in the
following, the backlight 8 will be described.
[Configuration of Backlight]
[0117] The backlight 8 is arranged in opposition to the light incident side
of the display section 20. The backlight 8 is of the type that a drive circuit
forming layer L81, a light emitting element forming layer L82 which includes
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the organic light emitting element 80 , a sealing layer 87, and a counter
substrate 88 are laminated in order, for example, on a support substrate 81,
starting from the opposite side of the display section 20. The plurality of
organic light emitting elements 80 are arranged in a matrix along mutually
opposite surfaces of the support substrate 81 and the counter substrate 88.
[0118] The support substrate 81 is made of, for example, a glass or plastic
material which would block transmission of water (moisture) and oxygen.
Since light is taken out from the counter substrate 88 in a top-emission type
element, the support substrate 81 may be made of either a permeable material
or an impermeable material. The support substrate 81 may be made of a
flexible plastic material when the display device is configured as a flexible
display.
[0119] A drive circuit which includes a plurality of drive elements 82
such as TFTs adapted to individually drive the organic light emitting elements
80 is disposed in the drive circuit forming layer L81. The drive circuit
includes, for example, signal lines, scanning lines, power supply tines and the
like in addition to the drive elements 82 and these elements and lines are
generally covered with a protection layer 83.
[0120] The organic light emitting element 80, an insulating layer 89, and
the sealing layer 87 which covers them are disposed in the light emitting
element forming layer L82.
[Configuration of Organic Light Emitting Element]
[0121] The organic light emitting element 80 is of the type that a first
electrode 84 as an anode electrode, an organic layer 85 including a light
emitting layer, and a second electrode 86 as a cathode electrode are laminated
in order, starting from the support substrate 81. The organic layer 85 and the
first electrode 84 are partitioned by an insulating layer 89 for every organic
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light emitting element 80. On the other hand, the second electrode 86 is
commonly provided for all the organic light emitting elements 80.
[0122] The organic layer 85 has a configuration in which, for example, a
positive hole injection layer, a positive hole transport layer, a light emitting
layer, and an electron transport layer are laminated in order, starting from the
first electrode 84. Incidentally, layers other than the light emitting layer may
be disposed on an as-needed basis.
[0123] The insulating layer 89 is disposed so as to fill a gap (which is
commonly formed) between the first electrodes 84 and between the organic
layers 85 of the adjacent organic light emitting elements 80. That is, the
insulating layer 89 is adapted to ensure insulation between the first electrode
84 and the second electrode 86 and to accurately define a light emitting region
of the organic light emitting element 80.
[0124] The sealing layer 87 is made of an insulating resin material such as,
for example, polyimide and/or the like similarly to the protection layer 83.
[0125] The counter substrate 88 is adapted to seal the organic light
emitting element 80 together with the sealing layer 87 and an adhesive layer
(not illustrated) which is made of thermosetting resin or the like, and is made
of a transparent glass or plastic material which transmits light generated from
the light emitting layer included in the organic layer 85.
[Operation and Effect of Backlight]
[0126] The backlight 8 makes it possible to emit light from the organic
layer 85 by activating one drive element 82 corresponding to a desired organic
light emitting element 80 and applying a voltage between the first electrode
84 and the second electrode 86 of the organic light emitting element 80.
Therefore, the backlight 8 makes it possible to form an arbitrary emission
pattern in the XY plane by appropriately selecting one organic light emitting
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element 80 from which light is to be emitted and activating one drive element
(TFT) 82 corresponding to each of the selected organic light emitting element
80. Owing to the above, it is possible to output, for example, linear-shaped
illumination light so as to direct toward the display section 20 also in the
backlight 8. Thus, the third embodiment attains the same effect as the first
embodiment.
[0127] Although the third embodiment is configured such that the drive
element 82 is disposed for every organic light emitting element 80 to
active-matrix-drive each organic light emitting element 80, an arbitrary
emission pattern may be formed by passive-matrix-driving each organic light
emitting element 80.
[Fourth Embodiment]
[0128] Next, a fourth embodiment of the present disclosure will be
described in detail with reference to the accompanying drawings.
Description has been made by illustrating the backlight 30 which includes the
light modulation element 3 or 5 utilizing the PDLC as the lighting unit in the
first embodiment. On the other hand, a display device according to the
fourth embodiment is of the type that a backlight 9 which includes a light
emitting diode 90, for example, illustrated in FIG. 22 is used in place of the
backlight 30 as the lighting unit. FIG. 22 is an enlarged sectional diagram
illustrating essential parts of the backlight 9. The display device according
to the fourth embodiment is configured in the same manner as the display
device 100 excepting a point that the backlight 9 is used. Thus, in the
following, the backlight 9 will be described.
[Configuration of Backlight]
[0129] The backlight 9 is arranged in opposition to the light incident side
of the display section 20. The backlight 9 is of the type that, for example, an
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anode take-out electrode 92, a contact section 93, an anode contact electrode
94, and a light emitting diode (LED) 90 are laminated in order on a support
substrate 91, starting from the opposite side of the display section 20. The
LED 90 is, for example, a gallium-nitride-based light emitting diode and has a
laminated structure which includes, for example, a clad layer 90A made of
p-GaN, an active layer 90B made of GaInN, and a window layer 90C made of
n-GaN. The plurality of LEDs 90 are arranged in a matrix along a surface of
the support substrate 91 and light is radiated from each LED 90 in a direction
of an arrow illustrated in the drawing by voltage application. The
surroundings of the LED 90 are filled with an insulating layer 95. A cathode
contact electrode 96 is disposed on a part of a light outgoing plane of the
window layer 90C. The cathode contact electrode 96 is connected to the
outside via a cathode take-out electrode 97.
[0130] The backlight 9 so configured also makes it possible to form an
arbitrary emission pattern in an XY plane by selectively emitting light from
the plurality of LEDs 90 which are arranged in a matrix. Thus, the backlight
9 makes it possible to output, for example, linear-shaped illumination light so
as to direct toward the display section 20. Therefore, the fourth embodiment
attains the same effect as the first embodiment. It is to be noted that either
an active-matrix-driving system or a passive-matrix-driving system may be
selected also in the fourth embodiment, and an LED having another structure
may be adopted.
[Fifth Embodiment]
[0131] Next, a fifth embodiment of the present disclosure will be
described in detail with reference to the accompanying drawings. A display
device according to the fifth embodiment is of the type that an electronic
particulate element 6 which contains an electronic toner 63B, for example, as
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illustrated in FIG. 23A in the backlight 30 as the lighting unit. FIG. 23A is a
sectional diagram illustrating an example of a configuration of the electronic
particulate element 6. The display device according to the fifth embodiment
is configured in the same manner as the display device 100 excepting a point
that the electronic particulate element 6 is used. Thus, in the following, the
electronic particulate element 6 will be described.
[Configuration of Electronic Particulate Element]
[0132] The electronic particulate element 6 is of the type that, for
example, a lower substrate 61, a plurality of lower electrodes 62, a light
modulation layer 63 which includes the plurality of electronic toners 63B, a
plurality of upper electrodes 65, and an upper substrate 66 are arranged in
order, starting from a position near the reflector 4. Here, an outer surface
(opposite to a surface on which the upper electrodes 65 are disposed) of the
upper substrate 66 is adhered to a rear surface of the light guiding plate 1.
The light modulation layer 63 is irradiated with illumination light from the
upper substrate 66.
[0133] The lower substrate 61 is made of, for example, an inorganic
material, a metallic material, a plastic material, and/or the like. The
inorganic material includes, for example, silicon (Si), silicon oxide (SiO,),
silicon nitride (SiN,), aluminum oxide (AlO,), and/or the like. The silicon
oxide includes glass, spin-on-glass (SOG), and/or the like. The metallic
material includes, for example, aluminum (Al), nickel (Ni), stainless steel,
and/or the like. The plastic material includes, for example, polycarbonate
(PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN),
polyether ether ketone (PEEK), and/or the like.
[0134] The lower substrate 61 may be either light-permeable or
light-impermeable because illumination light is radiated from the upper
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substrate 66. In addition, the lower substrate 61 may be either a rigid
substrate such as a wafer or may be made of a flexible thin-layered glass sheet
or film.
[0135] The upper substrate 66 is made of the same material as the lower
substrate 61. However, the upper substrate is light-permeable.
[0136] Both the plurality of lower electrodes 62 and the plurality of upper
electrodes 65 which are respectively disposed on opposite surfaces of the
lower substrate 61 and the upper substrate 66 are, for example, strip
electrodes each having a rectangular plane. The plurality of lower electrodes
62 are arranged separately from one another so as to, for example, extend in
the Y-axis direction as their longitudinal direction and to be arrayed in the
X-axis direction. On the other hand, the plurality of upper electrodes 65 are
arranged separately from one another so as to, for example, extend in the
X-axis direction as their longitudinal direction and to be arrayed in the Y-axis
direction. That is, in the electronic particulate element 6, each region where
the lower electrode 62 three-dimensionally intersects the upper electrode 65
serves as one light modulation cell 6S.
[01371 The lower electrode 62 is made of various conductive materials
such as, for example, metallic materials such as gold (Au), silver (Ag), copper
(Cu) and/or the like, compounds such as indium tin oxide (ITO), and/or the
like, other alloys, and/or the like. The upper electrode 65 is made of a
translucent conductive material (a transparent electrode material) such as, for
example, indium tin oxide (ITO), antimony tin oxide (ATO), fluorine-doped
tin oxide (FTO), aluminum-doped zinc oxide (AZO), and/or the like. The
upper substrate 66 is in contact with the light guiding plate 1 (see FIG. 4) and
is made of a material which is the same as the light guiding plate 1 in
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refractive index in order to ensure light-guiding property. As an alternative,
the light guiding plate I may be used also as the tipper substrate 66.
[0138] The light modulation layer 63 is of the type that the plurality of
electronic toners 63B are sealed into a space which is filled with air 63A.
The light modulation layer 63 is adapted to move the electronic toners 63B in
the Z-axis direction by applying a voltage between the lower electrode 62 and
the upper electrode 65, thereby creating contract by utilizing light scattering
characteristics of the electronic toners 63B. Each electronic toner 63B is a
white or almost white electrostatic fine particle. Specifically, the electronic
toner 63B contains metal oxides such as, for example, titanium oxide, zinc
oxide, zirconium oxide, barium titanate, potassium titanate, and/or the like as
constitutional materials. Since the electronic toner 63B exhibits a white or
almost white color, visible light is efficiently scattered and the intensity of
light reflected from the electronic toner 63B is increased. Therefore,
brighter illumination light is obtained.
[0139] Incidentally, it is preferable that the electronic toner 63B be liable
to be dispersed and charged over a long period of time. Thus, a dispersing
agent (or a charge modifier) may be used in order to make the electronic toner
63B disperse by electrostatic repulsion, surface treatment may be performed
on the electronic toner 63B, or both of them may be adopted simultaneously.
[Operation and Effect of Electronic Particulate Element]
[0140 ] The fifth embodiment is configured to selectively form a
non-scattering region 6A (described later) and a scattering region 6B
(described later) by passive-matrix-driving each light modulation cell 6S. In
the electronic particulate element 6, if a voltage is applied between the lower
electrode 62 and the upper electrode 65, the electronic toner 63B which has
been charged by the action of an electric field generated between the
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electrodes moves in the Z-axis direction and is positioned in the vicinity of a
surface of the upper electrode 65, for example, as illustrated in FIG. 23A.
Here, for example, the negatively charged electronic toner 63B is adsorbed to
the upper electrode 65 as a positive electrode. FIG. 23A illustrates a state
that the voltage has been applied between all the lower electrodes 62 and all
the upper electrodes 65. In the above mentioned case, visible light is
scattered over the entire surface with the electronic toners 63B to exhibit a
totally light-emitted state in which contrast is not substantially created when
observing the electronic particulate element 6 from above the upper substrate
66.
[0141] Here, for example, some lower electrodes 62 and some upper
electrodes 65 are selected and a voltage is applied between the selected
electrodes so as to have a polarity opposite to that illustrated in FIG. 23A.
That is, the voltage is applied such that, for example, the selected lower
electrode 62A functions as a positive electrode and the selected upper
electrode 65A functions as a negative electrode as illustrated in FIG. 23B.
When an electric field is generated between the selected lower electrode 62A
and upper electrode 65A, the electronic toners 63B which are present in a
region where the electric field has been generated move from the vicinity of
the surface of the upper electrode 65A to the vicinity of the surface of the
lower electrode 62A, for example, as illustrated in FIG. 23B. As a result,
visible light is scattered with the electronic toners 63B in the vicinity of the
surface of the lower electrode 62A in a light modulation cell 6S2 which is a
region where the lower electrode 62A three-dimensionally intersects the upper
electrode 65A and hence total reflection of the light guiding plate I is
maintained in the region. Thus, the light modulation cell 6S2 serves as the
non-scattering region 6A, the light modulation cell 6S other than the above
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serves as the scattering region 6B, and hence the luminance of the region 6B
is more increased than the non-scattering region 6A, when observing the
electronic particulate element 6 from above the upper substrate 66. Thus,
light is selectively emitted in an in-plane direction to exhibit a state that
contrast is created.
[0142] Therefore, the electronic particulate element 6 makes it possible to
form an arbitrary emission pattern in a plane. Owing to the above, it
becomes possible to output, for example, linear-shaped illumination light so
as to direct toward the display section 20 also in the backlight 30 which uses
the electronic particulate element 6 and hence the fifth embodiment attains the
same effect as the first embodiment. Incidentally, even if a black particle
that absorbs visible light such as, for example, carbon black is used as the
electronic toner 63B, contrast is created and hence an arbitrary emission
pattern is formed. However, it is rather preferable to use a white particle as
the electronic toner 63B because more effective utilization of light energy of
the light source 2 is possible by using the white particle.
[0143] In the fifth embodiment, the electronic toner 63B is caused to be
present in the air 63A in the light modulation layer 63. Therefore, the
electronic toner 63B becomes favorably liable to move and hence excellent
operational responsiveness is ensured in comparison with the electronic paper
7 in which the electrophoresis particles 76 are dispersed in a liquid phase.
[0144] Although the fifth embodiment is configured to form an arbitrary
emission pattern by passive-matrix-driving the light modulation layer 63, the
layer 63 may be active-matrix-driven. In the latter case, the plurality of
lower electrodes 62 (or the plurality of tipper electrodes 65) may be arranged
in a matrix and a drive element corresponding to each lower electrode 62 (or
each upper electrode 65) may be disposed. In addition, a partition wall that
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partitions the space in the light modulation layer 63 may be disposed for every
light modulation cell 6S in order to avoid non-uniformity (non-uniform
distribution) of the electronic toners 63B in the XY plane.
[Sixth Embodiment]
[0145] Next, an application example of the above mentioned display
device will be described.
[0146] The display device according to any one of the embodiments and
the modifications of the present technology disclosed herein is applicable to
an electronic system used for various applications and no limitation is set on
the kind of electronic system. The display device may be loaded on
electronic system, for example, of the kinds as follows. However, since
configurations of electronic system which will be described hereinbelow are
merely examples, the configuration may be appropriately modified and
altered.
[0147] FIG. 24A and FIG. 24B illustrate examples of an external
configuration of a so-called tablet type personal computer (PC). The tablet
type PC includes, for example, a display section 110, a non-display section
120 such as a housing which holds the display section 110, and an operation
section 130 such as a power switch. It is to be noted that the operation
section 130 may be disposed either on a front surface of the non-display
section 120, for example, as illustrated in FIG. 24A or on its upper surface, for
example, as illustrated in FIG. 24B. The display section 120 is a touch
screen (a touch panel) having an image displaying function and a position
inputting function (a pointing function).
[0148] The display device according to any one of the embodiments and
the modifications of the present technology may be used, other than the tablet
type PC illustrated in FIGs. 24A and 24B, as an image display part of, for
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example, a notebook personal computer (PC), a mobile phone, a digital still
camera, a video camera and/or an automotive navigation system.
[0149] Although the present technology has been described by giving
several embodiments and the modifications, the present technology is not
limited to these embodiments and modifications and may be modified and
altered in a variety of ways. For example, although in the above
embodiments and the modifications, description has been made by illustrating
the backlight which includes the light modulation elements utilizing the
PDLCs, the backlight which includes the electronic paper, the backlight which
includes the organic light emitting elements (OLEDs), and the backlight
which includes the LEDs have been described as the lighting units, the present
technology is not limited to the above.
[0150] Accordingly, it is possible to achieve at least the following
configurations from the above-described example embodiments and the
modifications of the disclosure.
(1) A method of displaying stereoscopic images with use of a display
device provided with a lighting unit and a display section, the lighting unit
including a plurality of two-dimensionally-arrayed light emitting sections,
and the display section performing image display through utilizing light from
the light emitting sections, the method including:
detecting an attitude of the display device relative to a viewer;
driving the plurality of light emitting sections on an individual basis,
to allow an emission pattern to be formed according to the attitude of the
display device; and
displaying a plurality of perspective images all together, according to
the attitude of the display device on the display section based on an external
image signal.
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(2) The display method according to (1), wherein the emission pattern is
formed in synchronization with display of the plurality of perspective images.
(3) The display method according to (1) or (2), wherein the emission
pattern allows linear-shaped illumination light to be generated.
(4) A display device, including:
a lighting unit including a plurality of two-dimensionally-arrayed light
emitting sections, and a drive section driving the plurality of light emitting
sections on an individual basis; and
a display section including a plurality of pixels to perform image
display through utilizing light from the light emitting sections.
(5) The display device according to (4), further including a sensor section
detecting its own attitude relative to a viewer.
(6) The display device according to (5), wherein the sensor section is
configured of an acceleration sensor or an image recognition device.
(7) The display device according to (4) or (5), wherein the plurality of light
emitting sections form an emission pattern which allows a plurality of rays of
linear-shaped illumination light to be generated.
(8) The display device according to (7), further including a control section
driving the display section and the lighting unit, to allow the display section
to display a plurality of perspective images all together, and to allow the
lighting unit to form the emission pattern in synchronization with display of
the plurality of perspective images.
(9) An electronic system provided with a display device, the display device
including:
a lighting unit including a plurality of two-dimensionally-arrayed light
emitting sections, and a drive section driving the plurality of light emitting
sections on an individual basis; and
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a display section including a plurality of pixels to perform image
display through utilizing light from the light emitting sections.
(10) A lighting unit provided for a display device, the lighting unit
including:
a plurality of two-dimensionally-arrayed light emitting sections; and
a drive section driving the plurality of light emitting sections on an
individual basis.
(11) The lighting unit according to (10), wherein the drive section
includes:
a plurality of first wirings extending in a first direction;
a plurality of second wirings extending in a second direction which is
different from the first direction; and
a plurality of drive elements disposed corresponding to the plurality of
light emitting sections, respectively.
(12) The lighting unit according to (11), wherein the drive section includes
a voltage applying section applying a predetermined voltage based on an input
signal between one or more selected from the plurality of first wirings and one
or more selected from the plurality of second wirings.
[0151] The present disclosure contains subject matter related to that
disclosed in Japanese Priority Patent Application JP 2011-171926 filed in the
Japan Patent Office on August 5, 2011 and contains subject matter related to
that disclosed in Japanese Priority Patent Application JP 2011-221275 filed in
the Japan Patent Office on October 5, 2011, the entire content of each of
which is hereby incorporated by reference.
[0152] It should be understood by those skilled in the art that various
modifications, combinations, sub-combinations and alterations may occur
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depending on design requirements and other factors insofar as they are within
the scope of the appended claims or the equivalents thereof.
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What is claimed is:
1. A method of displaying stereoscopic images with use of a display
device provided with a lighting unit and a display section, the lighting unit
including a plurality of two-dimensionally-arrayed light emitting sections,
and the display section performing image display through utilizing light from
the light emitting sections, the method comprising:
detecting an attitude of the display device relative to a viewer;
driving the plurality of light emitting sections on an individual basis,
to allow an emission pattern to be formed according to the attitude of the
display device; and
displaying a plurality of perspective images all together, according to
the attitude of the display device on the display section based on an external
image signal.
2. The display method according to claim I, wherein the emission
pattern is formed in synchronization with display of the plurality of
perspective images.
3. The display method according to claim 1, wherein the emission
pattern allows linear-shaped illumination light to be generated.
4. A display device, comprising:
a lighting unit including a plurality of two-dimensionally-arrayed light
emitting sections, and a drive section driving the plurality of light emitting
sections on an individual basis; and
a display section including a plurality of pixels to perform image
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display through utilizing light from the light emitting sections.
5. The display device according to claim 4, further comprising a
sensor section detecting its own attitude relative to a viewer.
6. The display device according to claim 5, wherein the sensor
section is configured of an acceleration sensor or an image recognition device.
7. The display device according to claim 4, wherein the plurality of
light emitting sections form an emission pattern which allows a plurality of
rays of linear-shaped illumination light to be generated.
8. The display device according to claim 7, further comprising a
control section driving the display section and the lighting unit, to allow the
display section to display a plurality of perspective images all together, and to
allow the lighting unit to form the emission pattern in synchronization with
display of the plurality of perspective images.
9. An electronic system provided with a display device, the display
device comprising:
a lighting unit including a plurality of two-dimensionally-arrayed light
emitting sections, and a drive section driving the plurality of light emitting
sections on an individual basis; and
a display section including a plurality of pixels to perform image
display through utilizing light from the light emitting sections.
10. A lighting unit provided for a display device, the lighting unit
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comprising:
a plurality of two-dimensionally-arrayed light emitting sections; and
a drive section driving the plurality of light emitting sections on an
individual basis.
11. The lighting unit according to claim 10, wherein the drive
section includes:
a plurality of first wirings extending in a first direction;
a plurality of second wirings extending in a second direction which is
different from the first direction; and
a plurality of drive elements disposed corresponding to the plurality of
light emitting sections, respectively.
12. The lighting unit according to claim 11, wherein the drive
section includes a voltage applying section applying a predetermined voltage
based on an input signal between one or more selected from the plurality of
first wirings and one or more selected from the plurality of second wirings.