DESCRIPTION
Title of Invention
ILLUMINATION DEVICE AND DISPLAY UNIT
Technical Field
[0001] The present technology relates to a display unit capable of performing
two-dimensional display (planar display) and three-dimensional display (stereoscopic
display), and to an illumination device suitably applicable to a backlight of such a
display unit.
Background Art
[0002] Display units capable of performing three-dimensional display include display
units in which it is necessary for a viewer to wear special glasses and display units in
which it is unnecessary for a viewer to wear special glasses. The latter display unit
uses a lenticular lens or a parallax barrier in order to allow a stereoscopic picture to be
visually observed with naked eyes. Picture information is divided into information for
a right eye and information for a left eye by the lenticular lens or the parallax barrier,
and thus different pictures are observed by the right and left eyes. As a result,
three-dimensional display becomes possible.
[0003] In the case where the above-described parallax barrier is used, however,
resolution in two-dimensional display is degraded. Therefore, a technology of
performing three-dimensional display without impairing the resolution in
two-dimensional display is disclosed in PTL 1. In PTL 1, a parallax barrier is
configured of a liquid crystal element, and the liquid crystal element becomes a parallax
barrier in three-dimensional display by making a non-transmissive region. Then, in
two-dimensional display, making the entire surface be transmissive prevents the liquid
crystal element from becoming a parallax barrier, and thus the entire picture on a
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display screen equally enters right and left eyes of a viewer.
Citation list
Patent Literature
[0004] PTL 1: Japanese Unexamined Patent Application Publication No. H03-119889
PTL 2: Japanese Unexamined Patent Application Publication No. HI 1-285030
Summary of Invention
[0005] In the method described in PTL 1, however, light is absorbed by the parallax
barrier in three-dimensional display, and thus display luminance is disadvantageous^
low.
[0006] In PTL 2, a technology of suppressing decrease in luminance by using a
cylindrical lens and a polymer dispersed liquid crystal (PDLC) in place of a parallax
barrier is disclosed. In the method described in PTL 2, however, when a viewer views
a display screen in an oblique direction, display quality is disadvantageous^ degraded
because of aberration of the cylindrical lens.
[0007] Therefore, it is desirable to provide a display unit capable of improving both
display luminance and display quality in three-dimensional display, and an illumination
device suitably applicable to such a display unit.
[0008] A display unit according to an embodiment of the technology includes: a
display panel having a plurality of pixels two-dimensionally arranged; a first
polarization plate and a second polarization plate that face each other with the display
panel in between; and an illumination device configured to illuminate the display panel
through the first polarization plate. The illumination device includes a first transparent
substrate and a second transparent substrate that are arranged to face each other with a
distance, a light source configured to apply light to an end surface of the first
transparent substrate or an end surface of the second transparent substrate, and a light
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modulation layer provided in a clearance between the first transparent substrate and the
second transparent substrate. Here, the light modulation layer is configured to exhibit
scattering property or transparency to the light from the light source depending on a
magnitude of an electric field. The light modulation layer includes a first region that
has optical anisotropy, and relatively high responsiveness to the electric field, and a
second region that has optical anisotropy, and relatively low responsiveness to the
electric field. The light modulation layer generates polarized light that has a
polarization component mainly in a direction parallel to a transmission axis of the first
polarization plate when the light modulation layer exhibits the scattering property.
[0009] In the display unit according to the embodiment of the technology, the light
modulation layer exhibiting scattering property or transparency to the light from the
light source depending on a magnitude of the electric field is provided in the
illumination device. Therefore, light propagating through a light guide plate is
allowed to be extracted from a region exhibiting scattering property (a scattering region).
Moreover, in the technology, the light modulation layer generates polarized light that
has a polarization component mainly in a direction parallel to the transmission axis of
the first polarization plate when the light modulation layer exhibits scattering property.
Therefore, as compared with a case where non-polarized light having the same
luminance is emitted from the illumination device, it is possible to allow the light of the
illumination device to enter the display panel more efficiently. Accordingly, even
when three-dimensional display is performed with use of pixels the number of which is
smaller than that in two-dimensional display, it is possible to perform three-dimensional
display with high display luminance. Incidentally, in the technology, it is unnecessary
to provide a parallax barrier for three-dimensional display. However, even if a
parallax barrier is provided on a light emission side of the illumination device, the rate
at which the light emitted from the light modulation layer is absorbed by the parallax
barrier is allowed to be extremely low by using a part of the light modulation layer as a
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scattering region and allowing the scattering region to correspond to a light transmissive
region of the parallax barrier. Moreover, in the embodiment of the technology, it is
unnecessary to provide a cylindrical lens for three-dimensional display. Therefore,
there is no possibility that aberration caused by a cylindrical lens occurs.
[0010] An illumination device according to an embodiment of the technology
includes: a first transparent substrate and a second transparent substrate that are
arranged to face each other with a distance; and a light source configured to apply light
to an end surface of the first transparent substrate or an end surface of the second
transparent substrate. The illumination device further includes a light modulation
layer that is provided in a clearance between the first transparent substrate and the
second transparent substrate, and is configured to exhibit scattering property or
transparency to the light from the light source depending on a magnitude of an electric
field. The light modulation layer includes a first region that has optical anisotropy,
and has relatively high responsiveness to the electric field, and a second region that has
optical anisotropy, and has relatively low responsiveness to the electric field. Here,
when the light modulation layer exhibits the scattering property, the light modulation
layer generates polarized light having a polarization component mainly in a first
direction.
[0011] In the illumination device according to the embodiment of the technology, the
light modulation layer that exhibits scattering property or transparency to light from the
light source depending on the magnitude of the electric field is provided. Therefore,
light propagating through a light guide plate is allowed to be extracted from a region
exhibiting scattering property (a scattering region). In addition, in the technology,
when the light modulation layer exhibits scattering property, the light modulation layer
generates polarized light that has a polarization component mainly in the first direction.
Therefore, when a polarization axis of light emitted from the illumination device has a
main component in a direction parallel to a transmission axis of a polarization pate
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provided on the illumination device, the light from the illumination device is allowed to
pass through the polarization plate more efficiently as compared with a case where
non-polarized light with the same luminance is emitted from the illumination device.
As a result, when the illumination device according to the technology is used as a
backlight of a display panel using a polarization plate, the light from the illumination
device is allowed to enter the display panel more efficiently. Accordingly, even in the
case where three-dimensional display is performed with use of the pixels the number of
which is smaller than that in two-dimensional display, it is possible to perform
three-dimensional display with high display luminance. Incidentally, in the
embodiment of the technology, it is unnecessary to provide a parallax barrier for
three-dimensional display. However, even if a parallax barrier is provided on a light
emission side of the illumination device, the rate at which the light emitted from the
light modulation layer is absorbed by the parallax barrier is allowed to be extremely low
by using a part of the light modulation layer as a scattering region and allowing the
scattering region to correspond to a light transmissive region of the parallax barrier.
Moreover, in the embodiment of the technology, it is unnecessary to provide a
cylindrical lens for three-dimensional display. Therefore, there is no possibility that
aberration caused by the cylindrical lens occurs.
[0012] In the illumination device and the display unit according to the respective
embodiments of the technology, polarized light is emitted from the illumination device,
and a part of the light modulation layer is allowed to be used as a scattering region.
Consequently, it is possible to improve both display luminance and display quality in
three-dimensional display.
Brief Description of Drawings
[0013] [FIG. 1] FIG. 1 is a diagram illustrating an example of a transmitting and
receiving system of a television broadcasting signal according to a first embodiment of
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the technology.
[FIG. 2] FIG. 2 is a diagram illustrating an example of a functional block of a receiver
in FIG. 1.
[FIG. 3] FIG. 3 is a sectional diagram illustrating an example of a structure of a
display unit in the receiver in FIG. 1.
[FIG. 4] FIG. 4 is a sectional diagram illustrating an example of a structure of a light
modulation device in FIG. 3.
[FIG. 5] FIG. 5 is a perspective view illustrating an example of an electrode structure
in FIG. 4.
[FIG. 6] FIG. 6 is a top view illustrating a first modification of the electrode structure
in FIG. 4.
[FIG. 7] FIG. 7 is a top view illustrating a second modification of the electrode
structure in FIG. 4.
[FIG. 8] FIG. 8 is a top view illustrating a third modification of the electrode structure
in FIG. 4.
[FIG. 9] FIG. 9 is a top view illustrating a fourth modification of the electrode
structure in FIG. 4.
[FIG. 10] FIG. 10 is a top view illustrating a fifth modification of the electrode
structure in FIG. 4.
[FIG. 11] FIG. 11 is a top view illustrating a sixth modification of the electrode
structure in FIG. 4.
[FIG. 12] FIG. 12 is a top view illustrating a seventh modification of the electrode
structure in FIG. 4.
[FIG. 13] FIG. 13 is a diagram illustrating an example of optical characteristics of an
ITO film and positional dependency of chromaticity change of a backlight.
[FIG. 14] FIG. 14 is a diagram illustrating an example of positional dependency of
guided-light spectrum.
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[FIG. 15] FIG. 15 is a sectional diagram illustrating another example of the structure
of the display unit in FIG. 3.
[FIG. 16] FIG. 16 is a schematic diagram for explaining an example of a function of a
light modulation layer in FIG. 4.
[FIG. 17] FIG. 17 is a schematic diagram for explaining another example of the
function of the light modulation layer in FIG. 4.
[FIG. 18] FIG. 18 is a schematic diagram for explaining an example of a function of
an illumination device in FIG. 3.
[FIG. 19] FIG. 19 is a diagram illustrating an example of a streaky structure of a bulk
in FIG. 4.
[FIG. 20] FIG. 20 is a diagram illustrating an example of relationship between a
polarization plate and an optical axis of the light modulation layer.
[FIG. 21] FIG. 21 is a diagram illustrating another example of the relationship
between the polarization plate and the optical axis of the light modulation layer.
[FIG. 22] FIG. 22 is a sectional diagram for explaining manufacturing processes of
the light modulation device in FIG. 4.
[FIG. 23] FIG. 23 is a sectional diagram for explaining manufacturing processes
following the manufacturing processes of FIG. 22.
[FIG. 24] FIG. 24 is a sectional diagram for explaining manufacturing processes
following the manufacturing processes of FIG. 23.
[FIG. 25] FIG. 25 is a schematic diagram for explaining three-dimensional display on
the display unit in FIG. 3.
[FIG. 26] FIG. 26 is a schematic diagram for explaining two-dimensional display on
the display unit in FIG. 3.
[FIG. 27] FIG. 27 is a schematic diagram for explaining an example of a function of
the light modulation layer in FIG. 4.
[FIG. 28] FIG. 28 is a schematic diagram for explaining another example of the
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function of the light modulation layer in FIG. 4.
[FIG. 29] FIG. 29 is a diagram for explaining effects of the light modulation layer in
FIG. 4 and effects of a light modulation layer according to a comparative example.
[FIG. 30] FIG. 30 is a diagram illustrating an example of an apparatus measuring
optical characteristics of the light modulation layer.
[FIG. 31] FIG. 31 is a diagram illustrating an example of results measured by the
apparatus in FIG. 30.
[FIG. 32] FIG. 32 is a diagram illustrating another example of the results measured by
the apparatus in FIG. 30.
[FIG. 33] FIG. 33 is a conceptual diagram for explaining isotropic scattering.
[FIG. 34] FIG. 34 is a conceptual diagram for explaining anisotropic scattering.
[FIG. 35] FIG. 35 is a schematic diagram for explaining an example of a function in a
modification of the light modulation layer in FIG. 4.
[FIG. 36] FIG. 36 is a schematic diagram for explaining another example of the
function in the modification of the light modulation layer in FIG. 4.
[FIG. 37] FIG. 37 is a diagram illustrating an example of relationship between the
polarization plate and an optical axis of the light modulation layer in FIG. 35.
[FIG. 38] FIG. 38 is a diagram illustrating another example of relationship between
the polarization plate and an optical axis of the light modulation layer in FIG. 36.
[FIG. 39] FIG. 39 is a sectional diagram illustrating an example of a structure of a
display section in a receiver according to a second embodiment of the technology.
[FIG. 40] FIG. 40 is a sectional diagram illustrating an example of a structure of a
light modulation device in FIG. 39.
[FIG. 41] FIG. 41 is a schematic diagram for explaining an example of a function of a
light modulation layer in FIG. 40.
[FIG. 42] FIG. 42 is a schematic diagram for explaining another example of the
function of the light modulation layer in FIG. 40.
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[FIG. 43] FIG. 43 is a diagram illustrating an example of relationship between a
polarization plate and an optical axis of the light modulation layer in FIG. 41.
[FIG. 44] FIG. 44 is a diagram illustrating another example of relationship between
the polarization plate and an optical axis of the light modulation layer in FIG. 42.
[FIG. 45] FIG. 45 is a schematic diagram for explaining an example of a function in a
modification of the light modulation layer in FIG. 41.
[FIG. 46] FIG. 46 is a schematic diagram for explaining another example of a function
of a modification of the light modulation layer in FIG. 42.
[FIG. 47] FIG. 47 is a diagram illustrating an example of relationship between the
polarization plate and an optical axis of the light modulation layer in FIG. 45.
[FIG. 48] FIG. 48 is a diagram illustrating another example of relationship between
the polarization plate and an optical axis of the light modulation layer in FIG. 46.
[FIG. 49] FIG. 49 is a sectional diagram illustrating a first modification of the
structure of the display unit according to any of the embodiments.
[FIG. 50] FIG. 50 is a sectional diagram illustrating a second modification of the
structure of the display unit according to any of the embodiments.
[FIG. 51] FIG. 51 is a sectional diagram illustrating a third modification of the
structure of the display unit according to any of the embodiments.
[FIG. 52] FIG. 52 is a sectional diagram illustrating a fourth modification of the
structure of the display unit according to any of the embodiments.
[FIG. 53] FIG. 53 is a sectional diagram illustrating a fifth modification of the
structure of the display unit according to any of the embodiments.
[FIG. 54] FIG. 54 is a sectional diagram illustrating a sixth modification of the
structure of the display unit according to any of the embodiments.
[FIG. 55] FIG. 55 is a sectional diagram illustrating an example of a structure of an
optical sheet in FIG. 54 together with a scattering region.
[FIG. 56] FIG. 56 is a diagram illustrating relationship between a contrast of a
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backlight and an angle formed by a projection and a linear illumination light beam.
[FIG. 57] FIG. 57 is a sectional diagram illustrating another example of the structure
of the optical sheet in FIG. 54 together with the scattering region.
[FIG. 58] FIG. 58 is a diagram illustrating an example of relationship between the
polarization plate and the optical axis of the light modulation layer.
[FIG. 59] FIG. 59 is a diagram illustrating another example of the relationship
between the polarization plate and the optical axis of the light modulation layer.
[FIG. 60] FIG. 60 is a sectional diagram illustrating a seventh modification of the
structure of the display unit according to any of the embodiments.
[FIG. 61] FIG. 61 is a sectional diagram illustrating an example of a structure of a
parallax barrier in FIG. 60.
[FIG. 62] FIG. 62 is a perspective view illustrating an eighth modification of the
electrode structure in FIG. 4.
[FIG. 63] FIG. 63 is a perspective view illustrating a ninth modification of the
electrode structure in FIG. 4.
[FIG. 64] FIG. 64 is a perspective view illustrating a tenth modification of the
electrode structure in FIG. 4.
[FIG. 65] FIG. 65 is a perspective view illustrating an eleventh modification of the
electrode structure in FIG. 4.
[FIG. 66] FIG. 66 is a plan view illustrating a twelfth modification of the electrode
structure in FIG. 4.
[FIG. 67] FIG. 67 is a plan view illustrating a thirteenth modification of the electrode
structure in FIG. 4.
[FIG. 68] FIG. 68 is a schematic diagram illustrating an example of relationship
between pixels of a display panel and backlight light.
[FIG. 69] FIG. 69 is a plan view illustrating a fourteenth modification of the electrode
structure in FIG. 4.
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[FIG. 70] FIG. 70 is a schematic diagram illustrating an example of the relationship
between the pixels of the display panel and the backlight light.
[FIG. 71] FIG. 71 is a plan view illustrating a fifteenth modification of the electrode
structure in FIG. 4.
[FIG. 72] FIG. 72 is a plan view illustrating a sixteenth modification of the electrode
structure in FIG. 4.
[FIG. 73] FIG. 73 is a plan view illustrating a seventeenth modification of the
electrode structure in FIG. 4.
[FIG. 74] FIG. 74 is a plan view illustrating an eighteenth modification of the
electrode structure in FIG. 4.
[FIG. 75] FIG. 75 is a plan view illustrating a nineteenth modification of the electrode
structure in FIG. 4.
[FIG. 76] FIG. 76 is a plan view illustrating a twentieth modification of the electrode
structure in FIG. 4.
[FIG. 77] FIG. 77 is a diagram illustrating an example of luminance distribution of
each electrode structure.
[FIG. 78] FIG. 78 is a plan view illustrating a twenty-first modification of the
electrode structure in FIG. 4.
[FIG. 79] FIG. 79 is a plan view illustrating a twenty-second modification of the
electrode structure in FIG. 4.
[FIG. 80] FIG. 80 is a plan view illustrating a twenty-third modification of the
electrode structure in FIG. 4.
[FIG. 81] FIG. 81 is a plan view illustrating a twenty-fourth modification of the
electrode structure in FIG. 4.
[FIG. 82] FIG. 82 is a plan view illustrating a twenty-fifth modification of the
electrode structure in FIG. 4.
[FIG. 83] FIG. 83 is a plan view illustrating a twenty-sixth modification of the
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electrode structure in FIG. 4.
[FIG. 84] FIG. 84 is a diagram illustrating an example of pattern density distribution
in the electrode structure in FIG. 80 to FIG. 83.
[FIG. 85] FIG. 85 is a diagram illustrating an example of luminance distribution when
an electrode having the pattern density of FIG. 84 is used.
[FIG. 86] FIG. 86 is a schematic diagram for explaining an example of a function of a
light modulation device having the electrode structure in any of FIG. 80 to FIG. 83.
[FIG. 87] FIG. 87 is a schematic diagram for explaining another example of the
function of the light modulation device having the electrode structure in any of FIG. 80
to FIG. 83.
[FIG. 88] FIG. 88 is a schematic diagram for explaining still another example of the
function of the light modulation device having the electrode structure in any of FIG. 80
to FIG. 83.
[FIG. 89] FIG. 89 is a perspective view illustrating an example of a configuration of
the light source according to any of the embodiments.
[FIG. 90] FIG. 90 is a perspective view illustrating an example of a configuration of a
light guide plate according to any of the embodiments.
[FIG. 91] FIG. 91 is a perspective view and a sectional diagram each illustrating
another example of the configuration of the light guide plate according to any of the
embodiments.
[FIG. 92] FIG. 92 is a schematic diagram illustrating an example of a function of the
light guide plate in FIG. 90 or FIG. 91.
[FIG. 93] FIG. 93 is a plan view illustrating a twenty-seventh modification of the
electrode structure in FIG. 4.
[FIG. 94] FIG. 94 is a plan view illustrating a twenty-eighth modification of the
electrode structure in FIG. 4.
[FIG. 95] FIG. 95 is a plan view illustrating a twenty-ninth modification of the
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electrode structure in FIG. 4.
[FIG. 96] FIG. 96 is a plan view illustrating a thirtieth modification of the electrode
structure in FIG. 4.
[FIG. 97] FIG. 97 is a diagram illustrating an example of pattern density distribution
of the electrode structure in any of FIG. 80 to FIG. 83 and FIG. 93 to FIG. 96.
[FIG. 98] FIG. 98 is a diagram illustrating an example of luminance distribution when
an electrode having the pattern density in FIG. 97 is used.
[FIG. 99] FIG. 99 is a plan view illustrating a thirty-first modification of the electrode
structure in FIG. 4.
[FIG. 100] FIG. 100 is a schematic diagram illustrating an example of relationship
between pixels of a display panel and backlight light.
[FIG. 101] FIG. 101 is a schematic diagram illustrating a first modification of the
relationship between the pixels of the display panel and the backlight light.
[FIG. 102] FIG. 102 is a schematic diagram illustrating a second modification of the
relationship between the pixels of the display panel and the backlight light.
[FIG. 103] FIG. 103 is a schematic diagram illustrating a third modification of the
relationship between the pixels of the display panel and the backlight light.
[FIG. 104] FIG. 104 is a schematic diagram illustrating a fourth modification of the
relationship between the pixels of the display panel and the backlight light.
[FIG. 105] FIG. 105 is a schematic diagram illustrating an example of time-divisional
driving in three-dimensional display.
[FIG. 106] FIG. 106 is a schematic diagram illustrating an example of the
time-divisional driving following FIG. 105.
[FIG. 107] FIG. 107 is a schematic diagram illustrating an example of the
time-divisional driving following FIG. 106.
[FIG. 108] FIG. 108 is a schematic diagram illustrating an example of the
time-divisional driving following FIG. 107.
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[FIG. 109] FIG. 109 is a sectional diagram illustrating a seventh modification of the
structure of the display unit according to any of the embodiments.
[FIG. 110] FIG. 110 is a diagram illustrating electrode layout according to an
embodiment.
[FIG. I l l ] FIG. 11 l i s a diagram illustrating the electrode layout in FIG. 110 on an
enlarged scale.
Description of Embodiments
[0014] Hereinafter, embodiments of the invention will be described in detail with
reference to the accompanying drawings. Note that description will be given in the
following order.
1. First embodiment
An example in which a light modulation device (horizontal aligned PDLC) is
used in a backlight
2. Second embodiment
An example in which a light modulation device (vertical aligned PDLC) is
used in a backlight
3. Modifications
4. Examples
[0015] <1. First Embodiment
(Configuration of Transmitting and Receiving System of Television Broadcasting
Signal)
FIG. 1 is a block diagram illustrating a configuration example of a transmitting
and receiving system of a television broadcasting signal 100A, including a receiver 200,
according to a first embodiment of the technology. The transmitting and receiving
system may include, for example, a transmitter 100 configured to transmit a television
broadcasting signal through wired communication (such as cable TV) or wireless
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communication (such as terrestrial digital waves and satellite waves), and the receiver
200 configured to receive the television broadcasting signal from the transmitter 100
through the above-described wired or wireless communication. Note that the receiver
200 corresponds to a specific example of "display unit" of the technology.
[0016] The television broadcasting signal 100A contains picture data for
two-dimensional display (planar display) or picture data for three-dimensional display
(stereoscopic display). In this case, the picture data for two-dimensional display
indicates two-dimensional picture data not containing perspective information.
Moreover, the picture data for three-dimensional display indicates two-dimensional
picture data containing perspective information, and the picture data for
three-dimensional display includes a plurality of pieces of two-dimensional picture data
with different perspectives. For example, the transmitter 100 may be a television
broadcasting signal transmitter placed in a broadcast station, or a server on the Internet.
[0017] (Functional Block of Receiver 200)
FIG. 2 is a block diagram illustrating a configuration example of the receiver
200. For example, the receiver 200 may be a television connectable to the
above-described wire or wireless communication. The receiver may include, for
example, an antenna terminal 201, a digital tuner 202, a demultiplexer 203, an
arithmetic circuit 204, and a memory 205. In addition, the receiver 200 may include,
for example, a decoder 206, a picture signal processing circuit 207, a graphic generation
circuit 208, a panel drive circuit 209, a display panel 210, a backlight 211, an audio
signal processing circuit 212, an audio amplifier circuit 213, and a speaker 214.
Furthermore, the receiver 200 may include, for example, a remote control reception
circuit 215, and a remote control transmitter 216. Note that the display panel 210
corresponds to a specific example of "display panel" of the technology, and the
backlight 211 corresponds to a specific example of "illumination device" of the
technology.
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[0018] The antenna terminal 201 is a terminal receiving a television broadcasting
signal received by a receiving antenna (not illustrated). For example, the digital tuner
202 may process the television broadcasting signal input to the antenna terminal 201,
and output a predetermined transport stream corresponding to a channel selected by a
user. For example, the demultiplexer 203 may extract a partial transport stream (TS)
corresponding to the channel selected by the user, from the transport stream obtained in
the digital tuner 202.
[0019] The arithmetic circuit 204 controls operation of each section in the receiver
200. For example, the arithmetic circuit 204 may store the partial TS obtained in the
demultiplexer 203 in the memory 205, or transmit the partial TS read from the memory
205 to the decoder 206. In addition, for example, the arithmetic circuit 204 may
transmit a control signal 204A specifying two-dimensional display or three-dimensional
display to the picture signal processing circuit 207 and the backlight 211. The
arithmetic circuit 204 sets the above-described control signal 204A, based on, for
example, setting information stored in the memory 205, predetermined information
included in the partial TS, or setting information input from the remote control
reception circuit 215.
[0020] For example, the memory 205 may hold setting information of the receiver 200
and performs data management. For example, the memory 205 may be capable of
holding the partial TS obtained in the demultiplexer 203 and setting information such as
a display method.
[0021] For example, the decoder 206 may perform decode processing on picture
packetized elementary stream (PES) packets included in the partial TS that is obtained
in the demultiplexer 203, to obtain picture data. Moreover, for example, the decoder
206 may perform decode processing on audio PES packets included in the partial TS
that is obtained in the demultiplexer 203, to obtain audio data. In this case, the picture
data indicates picture data for two-dimensional display or picture data for
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three-dimensional display.
[0022] For example, the picture signal processing circuit 207 and the graphic
generation circuit 208 may perform multi-image processing, superimposing processing
of graphics data, and the like, as necessary, on the picture data obtained in the decoder
206.
[0023] In the case where a signal specifying three-dimensional display is input as the
control signal 204A from the arithmetic circuit 204 and the picture data input from the
decoder 206 is picture data for three-dimensional display, for example, the picture
signal processing circuit 207 may create one piece of two-dimensional picture data with
use of a plurality of pieces of two-dimensional picture data with different perspectives
that are contained in the picture data for three-dimensional display input from the
decoder 206, and select the created two-dimensional picture data as picture data to be
output to the graphic generation circuit 208. For example, in the case where the
picture data for three-dimensional display contains two pieces of two-dimensional
picture data with different perspectives, the picture signal processing circuit 207 may
perform processing, for each row, to alternately arrange the two pieces of
two-dimensional picture data in a horizontal direction, and thus create one piece of
picture data in which the two pieces of two-dimensional picture data are alternately
arranged in the horizontal direction. Likewise, for example, in the case where the
picture data for three-dimensional display contains four pieces of two-dimensional
picture data with different perspectives, the picture signal processing circuit 207 may
perform processing, for each row, to arrange the four pieces of two-dimensional picture
data one by one periodically in the horizontal direction, and thus create one piece of
picture data in which the four pieces of two-dimensional picture data are arranged one
by one periodically in the horizontal direction.
[0024] In the case where a signal specifying two-dimensional display is input as the
control signal 204A from the arithmetic circuit 204 and the picture data input from the
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decoder 206 is picture data for three-dimensional display, for example, the picture
signal processing circuit 207 may select one piece of picture data of a plurality of pieces
of two-dimensional picture data with different perspectives contained in the picture data
for three-dimensional display that is input from the decoder 206, as picture data to be
output to the graphic generation circuit 208. In the case where a signal specifying
two-dimensional display as the control signal 204A is input from the arithmetic circuit
204 and the picture data input from the decoder 206 is picture data for two-dimensional
display, the picture signal processing circuit 207 selects the picture data for
two-dimensional display input from the decoder 206, as picture data to be output to the
graphic generation circuit 208.
[0025] For example, the graphic generation circuit 208 may generate an user interface
(UI) screen used in screen display. For example, the panel drive circuit 209 may drive
the display panel 210, based on the picture data output from the graphic generation
circuit 208.
[0026] The configurations of the display panel 210 and the backlight 211 will be
described later. For example, the audio signal processing circuit 212 may perform
processing such as D/A conversion on audio data obtained in the decoder 206. For
example, the audio amplifier circuit 213 may amplify an audio signal output from the
audio signal processing circuit 212 to supply the amplified audio signal to the speaker
214.
[0027] For example, the remote control reception circuit 215 may receive a remote
control signal transmitted from the remote control transmitter 216, and supply the
received remote control signal to the arithmetic circuit 204. For example, the
arithmetic circuit 204 may control each section in the receiver 200 according to the
remote control signal.
[0028] (Cross-Sectional Structure of Receiver 200)
FIG. 3 illustrates an example of a cross-sectional structure of the display
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section in the receiver 200. Note that FIG. 3 schematically illustrates the
cross-sectional structure, and actual dimensions and actual shapes are not limited to the
illustrated dimensions and the illustrated shapes. The receiver 200 includes a display
panel 210 and a backlight 211 disposed behind the display panel 210.
[0029] The display panel 210 includes a plurality of pixels arranged
two-dimensionally, and displays a picture when the respective pixels or specific pixels
are driven. For example, the display panel 210 may be a transmissive liquid crystal
display (LCD) panel in which the respective pixels or specific pixels are driven in
response to a picture signal, and may have a structure in which a liquid crystal layer is
sandwiched between a pair of transparent substrates. The display panel 210 may
include, for example, a polarization plate, a transparent substrate, pixel electrodes, an
alignment film, a liquid crystal layer, an alignment film, a common electrode, a color
filter, a transparent substrate, and a polarization plate in order from the backlight 211
side.
[0030] Note that the polarization plate on the backlight 211 side corresponds to a
specific example of "first polarization plate" of the technology, and the polarization
plate on a picture display surface side corresponds to a specific example of "second
polarization plate" of the technology. In addition, the polarization plate on the
backlight 211 side corresponds to a polarization plate 210B (see FIG. 20) described
later, and the polarization plate on the picture display surface side corresponds to the
polarization plate 210C (see FIG. 20) described later. Moreover, a section (more
specifically, a stacked section configured of the transparent substrate, the pixel
electrodes, the alignment film, the liquid crystal layer, the alignment film, the common
electrode, the color filter, and the transparent substrate) sandwiched by the pair of
polarization plates in the display panel 210 corresponds to a liquid crystal panel 210A
(see FIG. 20) described later.
[0031] The transparent substrate is formed of a substrate transparent to visible light,
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such as plate glass. Note that, although not illustrated, the transparent substrate on the
backlight 211 side is provided with an active drive circuit including thin film transistors
(TFTs) electrically connected to the pixel electrodes, wirings, and the like. For
example, the pixel electrode and the common electrode may be formed of indium tin
oxide (ITO). The pixel electrodes are two-dimensionally arranged on the transparent
substrate, and each of the pixel electrodes functions as an electrode for each pixel. On
the other hand, the common electrode is formed over a surface on the color filter, and
functions as a common electrode facing the respective pixel electrodes. The alignment
film may be formed of, for example, a polymer material such as polyimide, and
performs alignment on a liquid crystal.
[0032] For example, the liquid crystal layer may be formed of a liquid crystal of
vertical alignment (VA) mode, twisted nematic (TN) mode, or super twisted nematic
(STN) mode, and has a function of changing a direction of a polarization axis of emitted
light from the backlight 211 for each pixel, in response to a voltage applied from a drive
circuit (not illustrated). Note that changing arrangement of the liquid crystal in
multiple steps allows adjustment of the direction of a transmission axis for each pixel in
multiple steps. The color filter is configured by arranging color filters that separate
light having passed through the liquid crystal layer into three primary colors of red (R),
green (G), and blue (b), or color filters that separate the light into four colors of R, G, B,
and white (W), so as to correspond to the arrangement of the pixel electrodes.
[0033] The polarization plate is a kind of an optical shutter, and allows only light
(polarized light) that oscillates in a certain direction to pass therethrough. Note that
the polarization plate may be an absorption type polarization element absorbing light
(polarized light) that oscillates in a direction other than the transmission axis, and may
be preferably a reflective polarization element reflecting the light toward the backlight
211 side in terms of luminance improvement. The two polarization plates are arranged
so that respective polarization axes are different from each other by 90 degrees.
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Accordingly, the emitted light from the backlight 211 passes through the polarization
plates through the liquid crystal layer, or is shielded by the polarization plates.
[0034] For example, the backlight 211 may illuminate the display panel 210 from the
backside thereof, and may include a light guide plate 10, a light source 20 disposed on a
side surface of the light guide plate, a light modulation device 30 and a reflector 40 that
are arranged behind the light guide plate 10, and a drive circuit 50 driving the light
modulation device 30. Note that the light guide plate 10 corresponds to a specific
example of "first transparent substrate" or "second transparent substrate" of the
technology. The light source 20 corresponds to a specific example of "light source" of
the technology.
[0035] The light guide plate 10 guides light from the light source 20, which is
disposed on the side surface of the light guide plate, to a top surface of the light guide
plate 10. The light guide plate 10 may have a shape corresponding to the display panel
210 disposed on the top surface of the light guide plate 10, for example, a rectangular
parallelepiped shape enclosed by a top surface, a bottom surface, and side surfaces.
Note that, in the following description, the side surface receiving the light from the light
source 20 of the side surfaces of the light guide plate 10 is referred to as a light incident
surface 10A. Incidentally, the light incident surface 10A corresponds to a specific
example of "end surface" of the technology. For example, the light guide plate 10 may
have a predetermined patterned shape on the top surface or the bottom surface or both,
and have a function of scattering and uniformizing the light entering from the light
incident surface 10A. Note that, when the luminance is uniformized through
modulation of a voltage to be applied to the backlight 211, a flat light guide plate not
subjected to patterning may be used as the light guide plate 10. For example, the light
guide plate 10 may mainly contain a transparent thermoplastic resin such as a
polycarbonate resin (PC) and an acrylic resin (polymethyl methacrylate (PMMA)).
[0036] The light source 20 is a linear light source, and for example, may be
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configured of a hot cathode fluorescent lamp (HCFL), a cold cathode fluorescent lamp
(CCFL), or a plurality of light emitting diodes (LEDs) arranged in line. When the light
source 20 is configured of a plurality of LEDs, all of the LEDs may be preferably white
LEDs in terms of efficiency, decrease in thickness, and uniformity. Incidentally, for
example, the light source 20 may include red LEDs, green LEDs, and blue LEDs. The
light source 20 may be provided on only one side surface of the light guide plate 10 (see
FIG. 3), or may be provided on two side surfaces, three side surfaces, or all side
surfaces of the light guide plate 10.
[0037] The reflector 40 allows light leaking from the back of the light guide plate 10
through the light modulation device 30 to return to the light guide plate 10 side, and for
example, may have a function of reflection, diffusion, and scattering. This makes it
possible to efficiently utilize the emitted light from the light source 20, and contributes
to improvement of front luminance. For example, the reflector 40 may be formed of
foamed polyethylene terephthalate (PET), an evaporated silver film, a multilayer
reflective film, white PET, or the like. Note that, for example, the reflective film 40
may be omitted as necessary, as will be described later.
[0038] In the present embodiment, the light modulation device 30 may be closely
adhered to the back (the bottom surface) of the light guide plate 10 without an air layer,
and may be bonded to the back of the light guide plate 10 with an adhesive layer (not
illustrated) in between, for example. For example, as illustrated in FIG. 4, the light
modulation device 30 may be configured by arranging a transparent substrate 31, a
lower electrode 32, an alignment film 33, a light modulation layer 34, an alignment film
35, an upper electrode 36, and a transparent substrate 37 in order from the reflector 40
side. Note that the lower electrode 32 corresponds to a specific example of "first
electrode" of the technology, and the upper electrode 36 corresponds to a specific
example of "second electrode" of the technology.
[0039] The transparent substrates 31 and 37 support the light modulation layer 34, and
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are each typically formed of a substrate transparent to visible light such as a glass plate
and a plastic film. The lower electrode 32 is provided on a surface of the transparent
substrate 31 opposed to the transparent substrate 37, and may be formed of, for example,
a solid film (a single planar electrode) that is formed over the entire plane as illustrated
by a partial illustration of the light modulation device 30 in FIG. 5. Moreover, the
upper electrode 36 is provided on a surface of the transparent substrate 37 opposed to
the transparent substrate 31, and may be configured of, for example, a plurality of (two
or more) partial electrodes 36A as illustrated in FIG. 5. Incidentally, the partial
electrode 36A corresponds to a specific example of "first partial electrode" of the
technology.
[0040] Each of the plurality of partial electrodes 36A has a strip shape extending in
one direction in the plane (in a direction parallel to the light incident surface 10A). A
specific number of partial electrodes 36A (hereinafter, referred to as "partial electrodes
36B") among the plurality of partial electrodes 36A are used to generate a linear
illumination light beam when three-dimensional display is performed in the receiver
200. Note that the partial electrode 36B corresponds to a specific example of "second
partial electrode" of the technology. The plurality of partial electrodes 36B are
arranged at a pitch PI (a pitch equal to or close to a pixel pitch P2 (see FIG. 25))
corresponding to the pixel pitch P2 for performing three-dimensional display in the
receiver 200. A plurality of partial electrodes 36A other than the partial electrodes
36B of the plurality of partial electrodes 36A (hereinafter, referred to as "partial
electrodes 36C") are used, together with the partial electrodes 36B, to generate a planar
illumination light beam for performing two-dimensional display in the receiver 200.
In other words, when the two-dimensional display is performed in the receiver 200, all
of the partial electrodes 36A are used to generate the planar illumination light beam.
Note that the partial electrode 36C corresponds to a specific example of "third partial
electrode" of the technology. The plurality of partial electrodes 36B and the plurality
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of partial electrodes 36C are alternately arranged in an arrangement direction (in a
direction orthogonal to the light incident surface 10A). A width Wl of the partial
electrode 36B is smaller than a width W2 of the partial electrode 36C, and is smaller
than a width of the pixel in the display panel 210. The width Wl of the partial
electrode 36B may be preferably equal to or smaller than (the width of the pixel in the
display panel 210 - the thickness of the light modulation layer 34 * 2).
[0041] For example, as illustrated in FIG. 6, each of the partial electrodes 36A may
have a block shape, and the plurality of partial electrodes 36A may be arranged
two-dimensionally. In this case, when a certain number of the partial electrodes 36A
are regarded as one linear electrode 36D, each of the linear electrodes 36D may be used
as the partial electrode 36B or 36C described above. For example, a specific number
of linear electrodes 36D of the plurality of linear electrodes 36D may be used as the
partial electrodes 36B. A plurality of linear electrodes 36D other than the linear
electrodes 36D used as the partial electrodes 36B are used as the partial electrodes 36C.
At this time, the linear electrode 36D corresponds to a specific example of "first partial
electrode" of the technology, the partial electrode 36B corresponds to a specific
example of "second partial electrode" of the technology, and the partial electrode 36C
corresponds to a specific example of "third partial electrode" of the technology.
[0042] Incidentally, in the case where each of the partial electrodes 36A has a block
shape, and the plurality of partial electrodes 36A are arranged two-dimensionally, when
three-dimensional display is performed in the display unit, each of the partial electrodes
36A may be used to generate a point illumination light beam. Moreover, in the case
where each of the partial electrodes 36A has a block shape and the plurality of partial
electrodes 36A are arranged two-dimensionally, when two-dimensional display in
which different two-dimensional pictures are allowed to be perceived from two
perspectives is performed in the receiver 200, each of the partial electrodes 36A may be
used to generate a point illumination light beam.
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[0043] In addition, for example, as illustrated in FIG. 7, each of the partial electrodes
36C may be configured of a plurality of strip-shaped partial electrodes 36E each
extending in one direction in the plane (in the direction parallel to the light incident
surface 10A). At this time, a width of the partial electrode 36E may be equal to the
width of the partial electrode 36B. Note that the partial electrode 36E corresponds to a
specific example of "third partial electrode" of the technology. Moreover, for example,
as illustrated in FIG. 8, the linear electrode 36D used as the partial electrode 36C may
be configured of the plurality of partial electrodes 36A arranged two-dimensionally.
In this case, when a part of the plurality of partial electrodes 36A included in the linear
electrode 36D is regarded as one linear electrode 36F, each linear electrode 36F may
extend in one direction in the plane (in the direction parallel to the light incident surface
10A). At this time, the linear electrode 36F corresponds to a specific example of "third
partial electrode" of the technology.
[0044] Moreover, for example, as illustrated in FIG. 9, each of the plurality of partial
electrodes 36A may extend in a direction obliquely intersecting the light incident
surface 10A at an angle other than the right angle. At this time, the partial electrode
36A corresponds to a specific example of "first partial electrode" of the technology, the
partial electrode 36B corresponds to a specific example of "second partial electrode" of
the technology, and the partial electrode 36C corresponds to a specific example of "third
partial electrode" of the technology. Moreover, in the case where each of the partial
electrodes 36A has a block shape and the plurality of partial electrodes 36A are
arranged two-dimensionally, each of the linear electrodes 36D may extend in the
direction obliquely intersecting the light incident surface 10A at an angle other than the
right angle, for example, as illustrated in FIG. 10. In this case, when the plurality of
partial electrodes 36A are regarded as one linear electrode 36D, each linear electrode
36D may be used as the partial slectrode 36B or 36C described above. For example, a
specific number of linear electrodes 36D of the plurality of linear electrodes 36D may
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be used as the partial electrodes 36B, and a plurality of linear electrode 36D except for
the partial electrodes 36D used as the partial electrodes 36B may be used as the partial
electrodes 36C. At this time, the linear electrode 36D corresponds to a specific
example of "first partial electrode" of the technology, the partial electrode 36B
corresponds to a specific example of "second partial electrode" of the technology, and
the partial electrode 36C corresponds to a specific example of "third partial electrode"
of the technology.
[0045] Moreover, for example, as illustrated in FIG. 11, each of the partial electrodes
36C may be configured of a plurality of strip-shaped partial electrodes 36E each
extending in the direction obliquely intersecting the light incident surface 10A at an
angle other than the right angle. At this time, the width of the partial electrode 36E
may be equal to the width of the partial electrode 36B. Note that the partial electrode
36E corresponds to a specific example of "third partial electrode" of the technology.
In addition, for example, as illustrated in FIG. 12, in the case where the linear electrode
36D used as the partial electrode 36C is configured of the plurality of partial electrodes
36A arranged two-dimensionally, when a part of the plurality of partial electrodes 36A
included in the linear electrode 36D are regarded as one linear electrode 36F, each
linear electrode 36F may extend in the direction obliquely intersecting the light incident
surface 10A at an angle other than the right angle. At this time, the partial electrode
36F corresponds to a specific example of "third partial electrode" of the technology.
[0046] At least the upper electrode 36 (the electrode on the top surface side of the
backlight 211) of the lower electrode 32 and the upper electrode 36 is configured of a
transparent conductive film. For example, the transparent conductive film may
preferably have characteristics represented by the following expression (see (A) of FIG.
13). For example, the transparent conductive film may be formed of a film containing
ITO (hereinafter, referred to as "ITO film"). Note that the lower electrode 32 and the
upper electrode 36 may be formed of indium zinc oxide (IZO), a metal nanowire, a
26
SP323030
carbon nanotube, graphene, or the like.
[0047] | A1-A2 | < 2.00
Al: maximum light absorptivity (%) in a range of 450 nm to 650 nm both inclusive
A2: minimum light absorptivity (%) in a range of 450 nm to 650 nm both inclusive
[0048] Visible light is used as illumination light, and thus a difference in light
absorption of the transparent conductive film may be preferably small within a range of
380 nm to 780 nm both inclusive. The difference between the maximum value and the
minimum value of the light absorptivity within the range of 380 nm to 780 nm both
inclusive may be preferably 10.00 or less, and more preferably 7.00 or less. In
particular, when the transparent conductive film is applied to a backlight or the like, the
difference between the maximum value and the minimum value of the light absorptivity
within a range of a wavelength region of the used light source may be preferably 2.00 or
less, and more preferably 1.00 or less. When a typical LED light source or the like is
used as the light source, the difference between the maximum value and the minimum
value of the light absorptivity within a light wavelength range of 450 nm to 650 nm
both inclusive may be preferably 2.00 or less, and more preferably 1.00 or less. Note
that the absorptivity was measured with use of V-550 manufactured by JASCO
Corporation, the reflectance and the transmittance were measured under the condition of
5 degree incident from a substrate normal direction, and a value obtained by subtracting
the value of the reflectance and the transmittance from 100% was regarded as the
absorptivity.
[0049] As described above, in the case where the transparent conductive film has the
characteristics represented by the above-described expression, when the light emitted
from the light source 20 repeatedly passes through the transparent conductive film in the
light modulation device 30 during the propagation of the light in the light guide plate 10,
wavelength dependency of absorption in the transparent conductive film is suppressed.
When the transparent conductive film is formed of a typical ITO film, for example, as
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illustrated by dashed lines in (B) and (C) of FIG. 13 and by an arrow in (A) of FIG. 14,
the component on the long wavelength side is increased as the distance from the light
source 20 is increased. On the other hand, when the transparent conductive film is
formed of the ITO film that is improved in film quality and has the characteristics
represented by the above-described expression, for example, as illustrated by solid lines
in (B) and (C) of FIG. 13 and in (B) of FIG. 14, the ratio in which the component on the
long wavelength side is changed depending on the distance from the light source 20 is
decreased. Note that AuV in the vertical axis in (B) and (C) of FIG. 13 is an index
increased as the component of the long wavelength side is increased.
[0050] Moreover, for example, when one or both of the pair of the lower electrode 32
and the upper electrode 36 included in the light modulation device 30 is formed of an
ITO film, a dye or a pigment that absorbs light on the long wavelength side more than
light on the short wavelength side may be preferably contained in any part of the optical
path guiding light (for example, one or both of the light guide plate 10 and the light
modulation device 30). As the dye or the pigment described above, known materials
may be used. In particular, when a process of ultraviolet irradiation is included in
formation processes of the light modulation layer 34, for example, after the formation of
the light modulation device 30, the light modulation device 30 and the light guide plate
10 containing the dye or the pigment may be preferably bonded to each other or the
section containing the dye or the pigment may be preferably protected by an ultraviolet
absorbing layer from ultraviolet ray so that the dye or the pigment is prevent from being
damaged by ultraviolet ray. As described above, adding the dye or pigment described
above to any part of the optical path guiding light suppresses wavelength dependency of
absorption of the light modulation device 30 containing the ITO film when the light
emitted from the light source 20 repeatedly passes through the light modulation device
30 during propagation of the light in the light guide plate 10.
[0051] Incidentally, the lower electrode 32 (the electrode on the bottom surface side
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SP323030
of the backlight 211) may not be formed of a transparent material, and may be formed
of, for example, a metal. Note that, when the lower electrode 32 is formed of a metal,
the lower electrode 32 also has a function of reflecting light that enters the light
modulation device 30 from the back of the light guide plate 10, as with the reflector 40.
Accordingly, in this case, for example, as illustrated in FIG. 15, the reflector 40 may be
omitted.
[0052] When the lower electrode 32 and the upper electrode 36 are viewed from the
normal direction of the light modulation device 30, sections of the light modulation
device 30 corresponding to parts where the lower electrode 32 and the upper electrode
36 face each other configure light modulation cells 30-1 and 30-2 (see FIG. 4). The
light modulation cell 30-1 is a section of the light modulation device 30 corresponding
to a part where the lower electrode 32 and the partial electrode 36B face each other, and
the light modulation cell 30-2 is a section of the light modulation device 30
corresponding to a part where the lower electrode 32 and the partial electrode 36C face
each other. The light modulation cell 30-1 and the light modulation cell 30-2 are
adjacent to each other.
[0053] Each of the light modulation cells 30-1 and 30-2 is separately and
independently driven by application of a predetermined voltage to the lower electrode
32 and the upper electrode 36 (the partial electrode 36A), and exhibits transparency
(optical transparency) or scattering property with respect to the light from the light
source 20, depending on a magnitude of the voltage applied between the lower electrode
32 and the upper electrode 36 (the partial electrode 3 6A). Note that the transparency
and the scattering property will be described in detail in the description of the light
modulation layer 34.
[0054] For example, the alignment films 33 and 35 may align a liquid crystal and a
monomer used for the light modulation layer 34. The kinds of the alignment film may
include,- fer example, a vertical alignment film and a horizontal alignment film, and in
29
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the present embodiment, the horizontal alignment film is used for the alignment films
33 and 35. Examples of the horizontal alignment film may include, for example, an
alignment film formed through rubbing treatment on polyimide, polyamidimide,
polyvinyl alcohol, and the like, and an alignment film provided with a groove shape by
transcription, etching, or the like. In addition, examples of the horizontal alignment
film may include, for example, an alignment film formed through oblique deposition of
an inorganic material such as silicon oxide, a diamond-like carbon alignment film
formed through ion beam irradiation, and an alignment film provided with electrode
pattern slits. When a plastic film is used as the transparent substrates 31 and 37,
polyamidimide capable of being formed at a temperature of 100°C or less may be
preferably used as the alignment films 33 and 35 because a firing temperature after the
alignment films 33 and 35 are applied to the surfaces of the transparent substrates 31
and 37, respectively, may be preferably as low as possible in manufacturing process.
[0055] Moreover, it is sufficient for both the vertical alignment film and the horizontal
alignment film to have a function of aligning the liquid crystal and the monomer, and
reliability in repeated application of a voltage desired for a typical liquid crystal display
is unnecessary. This is because the reliability by voltage application after device
fabrication is determined by an interface between polymerized monomer and the liquid
crystal. Moreover, for example, the liquid crystal and the monomer used for the light
modulation layer 34 may be allowed to be aligned also by application of an electric field
or a magnetic field between the lower electrode 32 and the upper electrode 36 even
when an alignment film is not used. In other words, ultraviolet irradiation during
application of an electric field or a magnetic field between the lower electrode 32 and
the upper electrode 36 enables fixing of alignment state of the liquid crystal and the
monomer in voltage-applied state. When a voltage is used for formation of the
alignment film, electrodes may be separately formed for alignment and for driving, or
dual-frequency liquid crystal in which the symbol of dielectric anisotropy is inverted by
30
SP323030
frequency may be used as a liquid crystal material. Moreover, when a magnetic field
is used for formation of the alignment film, a material having large magnetic
susceptibility anisotropy may be preferably used as the alignment film, and for example,
a material having a large number of benzene rings may be preferably used.
[0056] The light modulation layer 34 exhibits, depending on the magnitude of the
electric field, scattering property or transparency to the light from the light source 20.
The light modulation layer 34 exhibits transparency to the light from the light source 20
when the electric field is relatively small, and exhibits scattering property to the light
from the light source 20 when the electric field is relatively large. For example, as
illustrated in FIG. 4, the light modulation layer 34 may be a composite layer containing
a bulk 34A and a plurality of microparticles 34B dispersed in the bulk 34A. The bulk
34A and the microparticle 34B have optical anisotropy. Incidentally, the bulk 34A
corresponds to a specific example of "second region" of the technology, and the
microparticle 34B corresponds to a specific example of "first region" of the technology.
[0057] (A) of FIG. 16 schematically illustrates an example of the alignment state in
the microparticle 34B when the voltage is not applied between the lower electrode 32
and the upper electrode 36 (hereinafter, simply referred to as "during no-voltage
application"). Note that illustration of the alignment state in the bulk 34A is omitted in
(A) of FIG. 16. As used herein, the wording "during no-voltage application" is a
concept that encompasses a time period when a voltage that is smaller than the voltage
allowing the light modulation layer to exhibit scattering property and allows the light
modulation layer 34 to exhibit transparency is applied.
[0058] (B) of FIG. 16 illustrates an example of an index ellipsoid representing
refractive index anisotropy of each of the bulk 34A and the microparticle 34B during
no-voltage application. The index ellipsoid represents a refractive index of linear
polarized light entering from various directions by a tensor ellipsoid, and geometrically
represents a refractive index through observation of a cross-sectional surface of the
31
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ellipsoid from an entering direction of the light. (C) of FIG. 16 schematically
illustrates an example of a state where light LI traveling toward the front direction and
light L2 traveling toward oblique direction pass through the light modulation layer 34
during no-voltage application.
[0059] (A) of FIG. 17 schematically illustrates an example of the alignment state in
the microparticle 34B when the voltage is applied between the lower electrode 32 and
the upper electrode 36 (hereinafter, simply referred to as "during voltage application").
Note that illustration of the alignment state in the bulk 34A is omitted in (A) of FIG. 17.
As used herein, the warding "during voltage application" refers to a time period when
the voltage allowing the light modulation layer to exhibit scattering property is applied.
[0060] (B) of FIG. 17 illustrates an example of the index ellipsoid representing
refractive index anisotropy of each of the bulk 34A and the microparticle 34B during
voltage application. (C) of FIG. 17 schematically illustrates an example of a state
where the light LI traveling toward the front direction and the light L2 traveling toward
the oblique direction are scattered in the light modulation layer 34, during voltage
application.
[0061] For example, as illustrated in (A) and (B) of FIG. 16, the bulk 34A and the
microparticle 34B have configuration in which a direction of an optical axis AX1 of the
bulk 34A and a direction of an optical axis AX2 of the microparticle 34B are coincident
with (parallel to) each other during no-voltage application. Incidentally, the optical
axes AX1 and AX2 each indicate a line parallel to a traveling direction of a light beam
having a fixed refractive index irrespective of polarization direction. In addition, it is
unnecessary for the direction of the optical axis AX1 and the direction of the optical
axis AX2 to constantly coincide with each other, and the direction of the optical axis
AX1 may be deviated in some degree from the direction of the optical axis AX2 due to,
for example, manufacturing error.
[0062] Moreover, for example, the microparticle 34B may have a configuration in
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SP323030
which the optical axis AX2 is parallel to the light incident surface 10A of the light guide
plate 10 during no-voltage application. Further, for example, the microparticle 34B
may have a configuration in which the optical axis AX2 intersects the surfaces of the
transparent substrates 31 and 37 at a slight angle 01 during no-voltage application (see
(B) of FIG. 16). Note that the angle 01 will be described in detail in description of a
material forming the microparticle 34B.
[0063] On the other hand, for example, the bulk 34A may have a configuration in
which the optical axis AX1 of the bulk 34A is fixed irrespective of voltage application
between the lower electrode 32 and the upper electrode 36. Specifically, for example,
as illustrated in (A) and (B) of FIG. 16 and (A) and (B) of FIG. 17, the bulk 34A may
have a configuration in which the optical axis AX1 of the bulk 34A is parallel to the
light incident surface 10A of the light guide plate 10 as well as intersects the surfaces of
the transparent substrates 31 and 37 at the predetermined angle 91. In other words, the
optical axis AX1 of the bulk 34A is parallel to the optical axis AX2 of the microparticle
34B during no-voltage application.
[0064] Note that it is unnecessary for the optical axis AX2 to be constantly parallel to
the light incident surface 10A as well as to constantly 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 slightly different from
the angle 01 due to, for example, manufacturing error. In addition, it is unnecessary
for the optical axes AX1 and AX2 to be constantly parallel to the light incident surface
10A, and the optical axes AX1 and AX2 may intersect the light incident surface 10A at
a small angle due to, for example, manufacturing error.
[0065] At this time, it may be preferable that an ordinary refractive index of the bulk
34A be equal to that of the microparticle 34B, and an extraordinary refractive index of
the bulk 34A be equal to that of the microparticle 34B. In this case, for example, as
illustrated in (A) of FIG. 16, during no-voltage application, refractive index difference
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SP323030
is substantially eliminated in various directions including the front direction and the
oblique direction, and high transparency (light transparency) is obtainable. Therefore,
for example, as illustrated in (C) of FIG. 16, the light LI traveling toward the front
direction and the light L2 traveling toward the oblique direction are not scattered in the
light modulation layer 34, and pass through the light modulation layer 34. As a result,
for example as illustrated in (A) and (B) of FIG. 18, light L from the light source 20
(light from the oblique direction) is totally reflected by an interface (the bottom surface
of the transparent substrate 31 and the top surface of the light guide plate 10) of a
transparent region (a transmissive region 30A) of the light modulation layer 34, and
luminance of the transmissive region 30A (luminance of black display) is decreased as
compared with the case where light is uniformly emitted from the entire surface
(alternate long and short dash line in (B) of FIG. 18). Note that profile of front
luminance in (B) of FIG. 18 is obtained by providing a diffuser sheet 41 on the light
guide plate 10 and performing measurement through the diffuser sheet 41.
[0066] Note that the top surface of the light guide plate 10 that is one of interfaces of
the transmissive region 30A is in contact with a clearance existing between the display
panel 210 and the light guide plate 10, and the clearance may be preferably filled with a
material having a refractive index lower than that of the top surface of the light guide
plate 10. Although the layer formed of such a low-refractive-index material (a
low-refractive-index material layer 220 (see FIG. 3)) is typically air, the layer may be an
adhesive agent or a bonding agent formed of a low-refractive-index material.
[0067] For example, as illustrated in (A) and (B) of FIG. 17, during voltage
application, the bulk 34A and the microparticle 34B may have a configuration in which
the direction of the optical axis AX1 is different from (intersects or is substantially
orthogonal to) the direction of the optical axis AX2. Moreover, for example, during
voltage application, the microparticle 34B may have a configuration in which the
optical axis AX2 of the microparticle 34B is parallel to the light incident surface 10A of
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the light guide plate 10 as well as intersects the surfaces of the transparent substrates 31
and 37 at an angle 02 (for example, 90 degrees) larger than the angle 01. Note that the
angle 02 will be described in detail in description of a material forming the
microparticle 34B.
[0068] Therefore, during voltage application, in the light modulation layer 34, the
refractive index is increased in various directions including the front direction and the
oblique direction, and higher scattering property is obtainable. Accordingly, for
example, as illustrated in (C) of FIG. 17, the light LI traveling toward the front
direction and the light L2 traveling toward the oblique direction is scattered in the light
modulation layer 34. As a result, for example, as illustrated in (A) of FIG. 18, the light
L from the light source 20 (the light from the oblique direction) passes through the
interface of the scattering region 3 0B (the interface between the air and one of the
transparent substrate 31 and the light guide plate 10), and the light that has passed to the
reflector 40 side is reflected by the reflector 40 and then passes through the light
modulation device 30. Consequently, the luminance of the scattering region 30B is
extremely high as compared with the case where light is uniformly emitted from the
entire surface (alternate long and short dash line in (B) of FIG. 18), and luminance of
partial white display (luminance enhancement) is increased by a decreased amount of
the luminance of the transmissive region 30A.
[0069] Incidentally, the ordinary refractive index of the bulk 34A may be slightly
different from that of the microparticle 34B due to, for example, manufacturing error,
and for example, the difference therebetween may be preferably 0.1 or less, and more
preferably 0.05 or less. In addition, the extraordinary refractive index of the bulk 34A
may also be slightly different from that of the microparticle 34B due to, for example,
manufacturing error, and for example, the difference therebetween may be preferably
0.1 or less, and more preferably 0.05 or less.
[0070] In addition, the difference in refractive index (Anp = the extraordinary
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refractive index nep - the ordinary refractive index nop) of the bulk 34A and the
difference in refractive index (AnL = the extraordinary refractive index neL - the
ordinary refractive index noi,) of the microparticle 34B may be preferably as large as
possible, preferably 0.05 or more, and more preferably 0.1 or more, and still more
preferably 0.15 or more. This is because when the difference in refractive index of
each of the bulk 34A and the microparticle 34B is large, the scattering power of the
light modulation layer 34 is increased to easily disrupt light guiding condition, and the
light from the light guide plate 10 is easily extracted.
[0071] Moreover, a response speed to the electric field of the bulk 34A is different
from that of the microparticle 34B. The bulk 34A may have, for example, a streaky
structure (see (A) and (B) of FIG. 19), a porous structure, or a rod-like structure, that
has a response speed lower than that of the microparticle 34B. Incidentally, (A) and
(B) of FIG. 19 are polarizing microscope photographs when the electric field is applied
to the light modulation device 30, and streaky bright sections in (A) and (B) of FIG. 19
correspond to the above-described streaky structure. (A) of FIG. 19 shows a state of
the streaky structure of the bulk 34A when a weight ratio of the liquid crystal to the
monomer is set to 95:5, and (B) of FIG. 19 shows a state of the streaky structure of the
bulk 34A when the weight ratio of the liquid crystal to the monomer is set to 90:10.
For example, the bulk 34A may be formed of a polymer material obtained through
polymerization of a low-molecular monomer. For example, the bulk 34A may be
formed by polymerizing a material (for example, monomer) that is aligned along the
alignment direction of the microparticle 34B or the alignment direction of the alignment
films 33 and 35 and has alignment property and polymerizability, by heat or light or
both.
[0072] For example, the streaky structure, the porous structure, or the rod-like
structure of the bulk 34A may have a long axis in a direction that is parallel to the light
incident surface 10A of the light guide plate 10 and intersects the surfaces of the
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transparent substrates 31 and 37 at the slight angle 01. When the bulk 34A has the
streaky structure, an average size of the streaky tissue in a short axis direction may be
preferably 0.1 um or more and 10 urn or less, and more preferably 0.2 um or more and
2.0 um or less, in terms of improving scattering properly of guided light. When the
average size of the streaky tissue in the short axis direction is 0.1 um or more and 10 um
or less, the scattering power in the light modulation device 30 is substantially equivalent
in a visible region of 380 to 780 nm both inclusive. Therefore, only increase or
decrease of light of a specific wavelength component does not occur in the plane, and
thus balance in the visible region is achieved in the plane. When the average size of
the streaky tissue in the short axis direction is smaller than 0.1 um or larger than 10 um,
the scattering power of the light modulation device 30 is low irrespective of the
wavelength, and thus it is difficult for the light modulation device 30 to function as a
light modulation device.
[0073] Moreover, in terms of reducing wavelength dependency of scattering, the
average size of the streaky tissue in the short axis direction may be preferably 0.5 um or
more and 5 um or less, and more preferably within a range of 1 to 3 um both inclusive.
In such a case, when the light emitted from the light source 20 repeatedly passes
through the bulk 34A in the light modulation device 30 during propagation of the light
in the light guide plate 10, the wavelength dependency of the scattering in the bulk 34A
is suppressed. The size of the streaky tissue is observable under a polarizing
microscope, a confocal microscope, an electron microscope, and the like.
[0074] On the other hand, for example, the microparticle 34B may contain a liquid
crystal material mainly, and have a response speed sufficiently higher than that of the
bulk 34A. The liquid crystal material (a liquid crystal molecule) contained in the
microparticle 34B may be, for example, a rod-like molecule. As the liquid crystal
molecule contained in the microparticle 34B, a liquid crystal molecule having positive
dielectric constant anisotropy (so-called positive liquid crystal) may be preferably used.
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[0075] In this example, during no-voltage application, in the microparticle 34B, the
long axis direction of the liquid crystal molecule is parallel to the optical axis AX1. At
this time, the long axis of the liquid crystal molecule in the microparticle 34B is parallel
to the light incident surface 10A of the light guide plate 10 and intersects the surfaces of
the transparent substrates 31 and 37 at the slight angle 61. In other words, the liquid
crystal molecule in the microparticle 34B is aligned in a state of being inclined at the
angle 61 in a plane parallel to the light incident surface 10A of the light guide plate 10
during no-voltage application. The angle 61 is a so-called pretilt angle, and for
example may be preferably 0.1 degree or more and 30 degrees or less. The angle 61
may be more preferably 0.5 degree or more and 10 degrees or less, and still more
preferably 0.7 degree or more and 2 degrees or less. There is a tendency for scattering
to decrease in efficiency due to reasons described below when the angle 61 is large. In
addition, the azimuth in which the liquid crystal stands up during voltage application is
varied when the angle 61 is excessively small. For example, the liquid crystal may
even stand up in an azimuth changed by 180 degrees (reversed tilt). Accordingly, the
refractive index difference of the microparticle 34B and that of the bulk 34A are not
efficiently used, and thus there is a tendency of decrease in scattering efficiency and in
luminance.
[0076] Moreover, during voltage application, in the microparticle 34B, the long axis
direction of the liquid crystal molecule intersects or is orthogonal to (or is substantially
orthogonal to) the optical axis AX1. At this time, the long axis of the liquid crystal
molecule in the microparticle 34B is parallel to the light incidence surface 10A of the
light guide plate 10 and intersects the surfaces of the transparent substrates 31 and 37 at
the angle 62 (for example, 90 degrees) larger than the angle 61. In other words, the
liquid crystal molecule in the microparticle 34B is aligned in a state of being inclined by
the angle 62 in the plane parallel to the light incidence surface 10A of the light guide
plate 10 or in a state of erecting at the angle 62 (= 90°), during voltage application.
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[0077] As the above-described monomer staving the alignment property and the
polymerizability, although a material that has optical anisotropy and is capable of being
combined with a liquid crystal is sufficient, in the present embodiment, a low-molecular
monomer to be cured by ultraviolet ray may be preferable. Since it may be preferable
that the direction of optical anisotropy of the liquid crystal coincide with the direction of
the optical anisotropy of the material (polymer material) formed through polymerization
of the low-molecular monomer in the state of no-voltage application, the liquid crystal
and the low-molecular monomer may be preferably aligned in the same direction before
ultraviolet curing. In the case where a liquid crystal is used as the microparticle 34B,
when the liquid crystal is a rod-like molecule, it may be preferable that the shape of the
monomer material to be used also have a rod-like shape. As described above, it may
be preferable to use a material having both polymerizability and liquid crystallinity as a
monomer material, and the material may preferably contain, as a polymerizable
functional group, one or more functional groups selected from the group of an acrylate
group, a methacrylate group, an acryloyloxy group, a methacryloyloxy group, a vinyl
ether group, and an epoxy group. These functional groups may be polymerized by
irradiation of an ultraviolet ray, an infrared ray, or an electron beam, or heating. To
suppress deterioration in alignment degree at the time of ultraviolet irradiation, a
polyfunctionalized liquid crystal material may be added. When the bulk 34A has the
above-described streaky structure, bifunctional liquid-crystalline monomer may be
preferably used as a raw material of the bulk 34A. Moreover, monofunctional
monomer may be added in order to adjust temperature exhibiting liquid crystalinity or
tri- or more-functional monomer may be added in order to improve crosslink density, to
the raw material of the bulk 34A.
[0078] Incidentally, as described above, during no-voltage application, the optical axis
AX1 of the bulk 34A and the optical axis AX2 of the microparticle 34B both have a
component of the respective optical axes mainly in the same direction. During
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no-voltage application, as illustrated in FIG. 20, both the optical axes AX1 and AX2
face in the same direction, for example, in a rubbing direction of the alignment films 33
and 35. In addition, during no-voltage application, the optical axes AX1 and AX2 are
parallel to or substantially parallel to the light incidence surface 10A as illustrated in
FIG. 20. Further, during no-voltage application, the optical axes AX1 and AX2 are
parallel to or substantially parallel to the transparent substrate 31 as illustrated in FIG. 4
and FIG. 20. In other words, during no-voltage application, the optical axes AX1 and
AX2 roughly face in the Y-axis direction in FIG. 20.
[0079] Further, during no-voltage application, the optical axes AX1 and AX2 have a
component of the respective optical axes mainly in a direction parallel to the
transmission axis AX 10 of the polarization plate 210B on the backlight 211 side.
During no-voltage application, the optical axes AX1 and AX2 face in the direction
parallel to the transmission axis AX 10, for example, as illustrated in FIG. 20. The
transmission axis AX10 faces in the rubbing direction of the alignment films 33 and 35,
for example, as illustrated in FIG. 20. Note that a transmission axis AX11 of the
polarization plate 210C on the picture display surface side is orthogonal to the
transmission axis AX 10 of the polarization plate 210B on the backlight 211 side.
[0080] Moreover, as described above, during voltage application, the optical axis AX1
faces in the direction same as or substantially same as the direction during no-voltage
application. During voltage application, the optical axis AX1 contains the component
of the optical axis mainly in the direction parallel to the transmission axis AX 10 of the
polarization plate 210B, and for example, as illustrated in FIG. 21, the optical axis AX1
faces in the direction parallel to the transmission axis AX 10. During voltage
application, for example, the optical axis AX1 is parallel to or substantially parallel to
the light incidence surface 10A, and further is parallel to or substantially parallel to the
transparent substrate 31.
[0081] On the other hand, during voltage application, the optical axis AX2 is
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displaced in a predetermined direction due to influence of an electric field generated by
the voltage that is applied between the lower electrode 32 and the upper electrode 36.
For example, during voltage application, the optical axis AX2 intersects or is orthogonal
to (or substantially orthogonal to) the transparent substrate 31 as illustrated in FIG. 4
and FIG. 21. In other words, the optical axis AX2 is displaced (namely, stands up) in a
direction where an angle formed by the optical axis AX2 and a normal of the
transparent substrate 31 is decreased, by the voltage application between the lower
electrode 32 and the upper electrode 36. At this time, the optical axis AX2 is
orthogonal to or substantially orthogonal to the optical axis AX1, and is orthogonal to or
substantially orthogonal to the transparent substrate 31.
[0082] The state of the bulk 34A and the microparticle 34B during voltage application
or during no-voltage application may have a macroscopic distribution in the plane of the
light modulation layer 30. More specifically, the length, the thickness, and the density
of the streaky tissue, the pretilt angle 01, the weight ratio of the bulk 34A to the
microparticle 34B, the intersection angle between the optical axis AX1 of the bulk 34A
and the optical axis AX2 of the microparticle 34B during voltage application,
anisotropic degree of anisotropic diffusion, the angle of the alignment in the plane, the
angle of the alignment in the thickness direction, the helix angle of the alignment, and
the like may have macroscopic in-plane distribution in the light modulation layer 34.
As a method of providing the distribution as described above, it may be contemplated to
provide a distribution to the rubbing intensity, an irradiation amount of ultraviolet ray,
the thickness of the alignment film, the thickness of the substrate, a polarization
direction of alignment in the case of optical alignment, electric field application during
ultraviolet irradiation, magnetic field application during ultraviolet irradiation, and the
like. For example, when a liquid crystal monomer is polymerized into a polymer
through ultraviolet irradiation, the amount of the streaky tissue may be allowed to have
a distribution by providing a distribution to ultraviolet intensity. Accordingly, when
41
SP323030
an amount of the streaky tissue on a side closer to the light source 20 is decreased to
suppress scattering during voltage application and the amount of the streaky tissue on a
side distant from the light source 20 is increased to enhance scattering during voltage
application, the intensity of light to be emitted is allowed to be uniformized in plane.
[0083] For example, the drive circuit 50 may control the magnitude of the voltage
applied to a pair of electrodes (the lower electrode 32 and the upper electrode 36) in
each of the light modulation cells 30-1 and 30-2 so that the optical axis AX2 of the
microparticle 34B is parallel to or substantially parallel to the optical axis AXl of the
bulk 34A in the light modulation cell 30-2 and the optical axis AX2 of the microparticle
34B intersects or is orthogonal to the optical axis AXl of the bulk 34A in the light
modulation cell 30-1. Moreover, for example, the drive circuit 50 may control the
magnitude of the voltage applied to the pair of electrodes (the lower electrode 32 and
the upper electrode 36) in each of the light modulation cells 30-1 and 30-2 so that the
optical axis AX2 of the microparticle 34B intersects or is orthogonal to the optical axis
AXl of the bulk 34A in each of the light modulation cells 30-1 and 30-2. In other
words, the drive circuit 50 allows the directions of the optical axes AXl and AX2 of the
bulk 34A and the microparticle 34B to coincide (or substantially coincide) with each
other or to be different from each other (or be orthogonal to each other) through electric
field control.
[0084] The drive circuit 50 allows the backlight 211 to output a plurality of linear
illumination light beams when receiving a signal specifying three-dimensional display
as the control signal 204A (when three-dimensional display is performed). More
specifically, the drive circuit 50 applies a voltage allowing the light modulation layer 34
to exhibit scattering property, to the specific number of partial electrodes 36B of the
plurality of partial electrodes 36A, and applies a voltage allowing the light modulation
layer 34 to exhibit transparency, to the plurality of partial electrodes 36C other than the
partial electrodes 36B of the plurality of partial electrodes 36A, thereby allowing the
42
SP323030
backlight 211 to emit a plurality of linear illumination light beams, when receiving a
signal specifying three-dimensional display as the control signal 204A (when
three-dimensional display is performed). In other words, the drive circuit 50 controls
the magnitude of the voltage applied to the pair of electrodes (the lower electrode 32
and the partial electrode 36A) in each of the light modulation cells 30-1 and 30-2 so that
the optical axis AX2 of the microparticle 34B intersects the optical axis AX1 of the bulk
34A in each of the light modulation cells 30-1 and the optical axis AX2 of the
microparticle 34B is parallel to the optical axis AX1 of the bulk 34A in each of the light
modulation cells 30-2.
[0085] The drive circuit 50 may drive each of the partial electrodes 36B, for example,
in the state where the position of the partial electrodes 36A is fixed, when receiving a
signal specifying three-dimensional display as the control signal 204A (when
three-dimensional display is performed). At this time, for example, the drive circuit 50
may further apply a voltage allowing the light modulation layer 34 to exhibit
transparency (for example, the same voltage (such as a ground voltage)) to each of the
partial electrodes 36C and the lower electrode 32.
[0086] Note that, in the case where the partial electrodes 36A are grouped for each
pitch corresponding to the pixel pitch for performing three-dimensional display on the
display panel 210, when receiving a signal specifying three-dimensional display as the
control signal 204A (when three-dimensional display is performed), the drive circuit 50
may sequentially assign (namely, may drive) the plurality of partial electrodes 36A
included in each group to the partial electrode 36B within one frame period. At this
time, for example, the drive circuit 50 may further apply the voltage allowing the light
modulation layer 34 to exhibit transparency (for example, the same voltage (such as a
ground voltage)), to each of the partial electrodes 36C.
[0087] In addition, the drive circuit 50 allows the backlight 211 to emit a planar
illumination light beam when receiving a signal specifying two-dimensional display as
43
SP323030
the control signal 204A (when two-dimensional display is performed). For example,
the drive circuit 50 may apply a voltage allowing the light modulation layer 34 to
exhibit scattering property, to each of the light modulation cells 30-1 and 30-2. In
other words, the drive circuit 50 controls the magnitude of the voltage applied to the
pair of electrodes (the lower electrode 32 and the partial electrode 36A) in each of the
light modulation cells 30-1 and 30-2 so that the optical axis AX2 of the microparticle
34B intersects or is orthogonal to (or substantially orthogonal to) the optical axis AX1
of the bulk 34A in all of the light modulation cells 30-1 and 30-2 included in the
backlight 211.
[0088] Moreover, for example, in the case where the partial electrodes 36A are
grouped for each pitch corresponding to the pixel pitch for performing
three-dimensional display on the display panel 210, when receiving a signal specifying
two-dimensional display as the control signal 204A (when two-dimensional display is
performed), the drive circuit 50 may sequentially drive the plurality of partial electrodes
36A included in each group within one frame period. The drive circuit 50 may
sequentially drive the groups one by one, or multiple at a time.
[0089] Note that, when receiving a signal specifying two-dimensional display as the
control signal 204A as well as receiving a signal relating to picture data, the drive
circuit 50 may allow the backlight 211 to emit a planar illumination light beam (for
example, a planar illumination light beam partially dark in plane) having luminance
distribution corresponding to the picture data. Incidentally, in this case, the upper
electrode 36 may be preferably arranged in a layout corresponding to the pixels of the
display panel 210. When the upper electrode 36 is arranged in the layout
corresponding to the pixels of the display panel 210, the drive circuit 50 applies,
according to the picture data, a voltage allowing the light modulation layer to exhibit
scattering property, to some of the light modulation cells 30-1 and 30-2, and a voltage
allowing the light modulation layer 34 to exhibit transparency, to the other of the light
44
SP323030
modulation cells 30-1 and 30-2.
[0090] Hereinafter, a method of manufacturing the backlight 211 according to the
present embodiment will be described with reference to (A) to (C) of FIG. 22 to (A) to
(C) of FIG. 24.
[0091] At first, a transparent conductive film 36R made of, for example, ITO is
formed on the transparent substrate 37 configured of a glass substrate or a plastic film
substrate ((A) of FIG. 22). Then, after a resist layer is formed on the entire surface
thereof, an electrode pattern is formed on the resist layer through patterning.
Subsequently, the upper electrode 36 (the partial electrodes 36A) is formed through
exposure and development, and the resist layer is then removed ((B) of FIG. 22).
[0092] As the method of patterning, for example, photolithography, laser processing,
pattern printing, screen printing, and the like may be used. Moreover, for example,
predetermined heating may be performed after screen printing is performed using the
"Hyper Etch" material by Merck & Co., Inc., and then washing may be performed to
perform patterning. The electrode pattern is determined by driving method and the
number of segments in partial driving. For example, the electrode pattern may be
processed at the pixel pitch of the display unit used or a pitch closed thereto. The
process width of the electrode may be, although depending on the process method,
preferably as small as possible in terms of light extraction efficiency. The process
width of the electrode may be, for example, 50 urn or less, preferably 20 um or less, and
more preferably 5 um or less. Moreover, ITO nanoparticles may be pattern-printed,
and then the ITO nanoparticles may be fired to form the electrode pattern.
[0093] Subsequently, the alignment film 35 is applied to the entire surface, followed
by drying and firing ((C) of FIG. 22). When a polyimide-based material is used as the
alignment film 35, N-methyl-2-pyrroridone (NMP) is frequently used as a solvent, and
at this time, a temperature of about 200°C is necessary in the atmosphere. Note that, in
this case, when a plastic substrate is used as the transparent substrate 37, the alignment
45
SP323030
film 35 may be dried in a vacuum at 100°C and fired. After that, rubbing treatment is
performed on the alignment film 35. As a result, the alignment film 35 functions as an
alignment film for horizontal alignment, and further a pretilt is allowed to be formed in
the rubbing direction of the alignment film 35.
[0094] Likewise, a transparent conductive film made of ITO or the like is formed on
the transparent substrate 31 that is configured of a glass substrate or a plastic film
substrate. Then, after a resist layer is formed on the entire surface, an electrode pattern
is formed on the resist layer through patterning. Subsequently, the lower electrode 32
is formed through exposure and development, and the resist layer is then removed.
After that, the alignment film 33 is applied on the entire surface, followed by drying and
firing. Thereafter, rubbing treatment is performed on the alignment film 33. As a
result, the alignment film 32 functions as an alignment film for horizontal alignment,
and further a pretilt is allowed to be formed in the rubbing direction of the alignment
film 33.
[0095] Next, spacers 38 for forming a cell gap are spread on the alignment film 35 by
a dry method or a wet method ((A) of FIG.23). Note that, when the light modulation
cells 30-1 and 30-2 are formed by vacuum bonding method, the spacers 38 may be
mixed into a mixture to be dropped. In addition, instead of the spacers 38, columnar
spacers may be formed by photolithography. Subsequently, a seal agent pattern 39 for
bonding and for preventing leakage of liquid crystal may be applied, for example, in a
frame shape on the alignment film 33 ((B) of FIG. 23). The seal agent pattern 39 is
allowed to be formed by a dispenser method or a screen printing method.
[0096] Although the vacuum bonding method (one drop fill method, ODF method)
will be described below, the light modulation cells 30-1 and 30-2 may be formed by a
vacuum injection method, a roll bonding system, or the like.
[0097] First, a mixture 42 of liquid crystal and monomer is dropped uniformly in a
plane by an amount corresponding to a volume that is determined from the cell gap, a
46
SP323030
cell area, and the like ((C) of FIG. 23). Although a precise dispenser of linear guide
system may be preferably used for dropping the mixture 42, the seal agent pattern 39
may be used as a bank and a dye coater or the like may be used.
[0098] The above-described material may be used for the liquid crystal and the
monomer, and the weight ratio of the liquid crystal and the monomer may be 98:2 to
50:50, may be preferably 95:5 to 75:25, and more preferably 92:8 to 85:15. The drive
voltage is allowed to be decreased by increasing the rate of the liquid crystal, however,
if the liquid crystal is excessively increased, whiteness tends to be lowered during
voltage application, or transparency is tends to be deteriorated due to lowering of
response speed after voltage off.
[0099] The mixture 42 is added with a polymerization initiator, in addition to the
liquid crystal and the monomer. The monomer rate in the polymerization initiator to
be added is adjusted within a range of 0.1 to 10 wt% depending on the wavelength of
ultraviolet ray to be used. The mixture 42 may be added with a polymerization
inhibitor, a plasticizer, a viscosity modifier, and the like, in addition thereto. When the
monomer is in a solid or a gel at room temperature, a metal cap, a syringe, and a
substrate may be preferably warmed.
[0100] After the transparent substrate 31 and the transparent substrate 37 are placed
on a vacuum bonding machine (not illustrated), evacuation and bonding are performed
((A) of FIG. 24). After that, the bonded body is released in the air, and the cell gap is
uniformized by uniform pressurization at atmosphere pressure. The size of the cell gap
is arbitrarily selectable based on relationship between white luminance (whiteness) and
the drive voltage, and may be 5 to 40 um both inclusive, may be preferably 6 to 20 um
both inclusive, and more preferably 7 to 10 um both inclusive.
[0101] After bonding, it may be preferable to perform alignment treatment as
necessary (not illustrated). When light leakage occurs at the time of inserting the
bonded cell between crossed-Nicols polarization plates, the cell is subjected to heat
47
SP323030
treatment for a certain time or is left at room temperature to be aligned. After that,
ultraviolet ray L3 is irradiated to polymerize the monomer, and thus polymer is formed
((B) of FIG. 24). In this way, the light modulation device 30 is manufactured.
[0102] It may be preferable that the temperature of the cell be prevented from being
varied during irradiation of the ultraviolet ray. It may be preferable to use an infrared
cut filter, and use a UV-LED or the like as a light source. The illuminance of the
ultraviolet ray affects the structure of the composite material, and thus the illuminance
may be preferably adjusted appropriately based on the liquid crystal material to be used,
the monomer material to be used, and the compositions thereof, may be preferably
within a range of 0.1 to 500 mW/cm2, and more preferably within a range of 0.5 to 30
mW/cm2. There is a tendency that the drive voltage is decreased as the illuminance of
the ultraviolet ray is low and preferable illuminance of the ultraviolet ray is selectable in
terms of both productivity and characteristics.
[0103] Then, the light modulation device 30 is bonded to the light guide plate 10 ((C)
of FIG. 24). Although the bonding may be performed through adhesion or bonding,
the adhesion or the bonding may be preferably performed with use of a material that has
a refractive index as close to that of the light guide plate 10 and that of the substrate
material of the light modulation device 30 as possible. Finally, lead wire (not
illustrated) is attached to the lower electrode 32 and the upper electrode 36. In this
way, the backlight 211 of the present embodiment is manufactured.
[0104] As described above, the process in which the light modulation device 30 is
fabricated and the light modulation device 30 is finally bonded to the light guide plate
10 has been described, however, the transparent substrate 37 provided with the
alignment film 35 may be previously bonded to the surface of the light guide plate 10
and then the backlight 211 may be fabricated. Moreover, the backlight 211 may be
fabricated by a single wafer system or a roll to roll system.
[0105] Next, functions and effects of the backlight 211 of the present embodiment
48
SP323030
will be described.
[0106] In the backlight 211 of the present embodiment, the voltage is applied to the
pair of electrodes (the lower electrode 32 and the partial electrode 36A) in each of the
light modulation cells 30-1 and 30-2 so that the optical axis AX2 of the microparticle
34B intersects or is orthogonal to (or substantially orthogonal to) the optical axis AXl
of the bulk 34A in each of the light modulation cells 30-1 and the optical axis AX2 of
the microparticle 34B is parallel to or substantially parallel to the optical axis AXl of
the bulk 34A in each of the light modulation cells 30-2. Accordingly, in the light
modulation device 30, each of the light modulation cells 30-1 becomes the scattering
region 3 0B, and each of the light modulation cells 30-2 becomes the transmissive region
30A. As a result, the light that has been emitted from the light source 20 and has
entered the light guide plate 10 passes through the transmissive region 30A of the light
modulation device 30, and is scattered in the scattering region 30B of the light
modulation device 30 (FIG. 25). Light that has passed through the bottom surface of
the scattering region 3 0B of the scattered light is reflected by the reflector 40 to return
to the light guide plate 10 again, and then is emitted from the top surface of the
backlight 211. In addition, light traveling toward the top surface of the scattering
region 3 0B of the scattered light passes through the light guide plate 10, and then is
emitted from the top surface of the backlight 211. As described above, in
three-dimensional display, light is scarcely emitted from the top surface of the
transmissive region 30A and light is emitted from the top surface of the scattering
region 30B. In this way, for example, as illustrated in FIG. 25, the plurality of linear
illumination light beams may be emitted in the front direction.
[0107] As a result, each of the linear illumination light beams emitted in the front
direction enters the back surface of the display panel 210. Therefore, for example,
when two-dimensional picture data for three-dimensional display is generated by the
picture signal processing circuit 207 so that each pixel row becomes three-dimensional
49
SP323030
pixel 210A in the pixel arrangement corresponding to each of the linear illumination
light beams, each of the linear illumination light beams enters, at the substantially same
angle, the pixel located in a position common to the respective three-dimensional pixels
210A (for example, in FIG. 25, pixel 210-1, 210-2, 210-3, or 210-4). As a result, from
the pixel located in a position common to the respective three-dimensional pixels 210A,
picture light modulated by the pixel is emitted at the predetermined angle. At this time,
a viewer views pictures with different parallaxes by his right and left eyes. Thus, the
viewer perceives display of a three-dimensional picture (a stereoscopic picture) on the
display panel 210.
[0108] Moreover, in the backlight 211 of the present embodiment, the voltage is
applied to the pair of electrodes (the lower electrode 32 and the partial electrode 3 6A) in
each of the light modulation cells 30-1 and 30-2 so that the optical axis AX2 of the
microparticle 34B intersects or is orthogonal to (or substantially orthogonal to) the
optical axis AX1 of the bulk 34A in each of the light modulation cells 30-1 and 30-2, in
two-dimensional display. Accordingly, the light that has been emitted from the light
source 20 and has entered the light guide plate 10 is scattered in the scattering region
3 0B that is formed in the entire light modulation device 30 (FIG. 26). Light that has
passed through the bottom surface of the scattering region 3 0B of the scattered light is
reflected by the reflector 40 to return to the light guide plate 10 again, and then is
emitted from the top surface of the backlight 211. In addition, light traveling toward
the top surface of the scattering region 30B of the scattered light passes through the
light guide plate 10, and then is emitted from the top surface of the backlight 211. As
described above, in two-dimensional display, for example, light may be emitted from
the entire top surface of the light modulation device 30, and a planar illumination light
beam may be emitted in the front direction.

CLAIMS
[Claim 1]
A display unit comprising:
a display panel having a plurality of pixels two-dimensionally arranged;
a first polarization plate and a second polarization plate that face each other
with the display panel in between; and
an illumination device configured to illuminate the display panel through the
first polarization plate, the illumination device including
a first transparent substrate and a second transparent substrate that are
arranged to face each other with a distance,
a light source configured to apply light to an end surface of the first
transparent substrate or an end surface of the second transparent substrate, and
a light modulation layer provided in a clearance between the first
transparent substrate and the second transparent substrate, the light modulation
layer being configured to exhibit scattering property or transparency to the light
from the light source depending on a magnitude of an electric field, wherein
the light modulation layer includes a first region and a second region, the first
region having optical anisotropy, and relatively high responsiveness to the electric field,
and the second region having optical anisotropy, and relatively low responsiveness to
the electric field, and
the light modulation layer generates polarized light when the light modulation
layer exhibits the scattering property, the polarized light having a polarization
component mainly in a direction parallel to a transmission axis of the first polarization
plate.
[Claim 2]
The display unit according to claim 1, wherein
when the light modulation layer exhibits the scattering property, the second
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region has a component of an optical axis mainly in a first direction, and the first region
has an optical axis in a direction intersecting or orthogonal to the optical axis of the
second region, and
when the light modulation layer exhibits the scattering property, the optical
axis of the second region faces in the direction parallel to the transmission axis of the
first polarization plate.
[Claim 3]
The display unit according to claim 1, wherein
the first region mainly contains a liquid crystal material,
the second region mainly contains a polymer material, and has a streaky
structure, a porous structure, or a rod-like structure, and
a longitudinal direction of the streaky structure, the porous structure, or the
rod-like structure is coincident with or substantially coincident with a polarization
direction of the polarized light.
[Claim 4]
The display unit according to claim 1, wherein when the light modulation layer
exhibits the scattering property, an optical axis of the second region faces in a direction
parallel to the end surface.
[Claim 5]
The display unit according to claim 1, wherein the illumination device further
includes a first electrode provided on a surface of the first transparent substrate, and a
second electrode provided on a surface of the second transparent substrate.
[Claim 6]
The display unit according to claim 5, further comprising a drive section
outputting a plurality of linear illumination light beams, wherein
the second electrode includes a plurality of first partial electrodes each
extending in the first direction and each having a stripe shape or a step shape, and
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the drive section, in performing three-dimensional display, applies a voltage
allowing the light modulation layer to relatively exhibit the scattering property, to a
specific plurality of second partial electrodes of the plurality of first partial electrodes,
and applies a voltage allowing the light modulation layer to relatively exhibit the
transparency, to a plurality of third partial electrodes, excluding the plurality of second
partial electrodes, of the plurality of first partial electrodes, thereby outputting the
plurality of linear illumination light beams.
[Claim 7]
The display unit according to claim 6, wherein the plurality of second partial
electrodes are arranged with a pitch corresponding to a pixel pitch for the
three-dimensional display on the display panel.
[Claim 8]
The display unit according to claim 7, wherein the first direction is a direction
obliquely intersecting the end surface.
[Claim 9]
The display unit according to claim 7, wherein the drive section drives each of
the second partial electrodes in a state where positions of the respective second partial
electrodes are fixed, in performing the three-dimensional display.
[Claim 10]
The display unit according to claim 7, wherein, when the plurality of first
partial electrodes are grouped for each pitch, the drive section sequentially assigns
within one frame period, in performing the three-dimensional display, the plurality of
first partial electrodes included in each group to the second partial electrodes, the pitch
corresponding to the pixel pitch for the three-dimensional display on the display panel.
[Claim 11]
The display unit according to claim 7, wherein, when the plurality of first
partial electrodes are grouped for each pitch, the drive section sequentially drives within
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one frame period, in performing the two-dimensional display, the plurality of first
partial electrodes included in each group, the pitch corresponding to the pixel pitch for
the three-dimensional display on the display panel.
[Claim 12]
The display unit according to claim 7, wherein the first electrode includes a
plurality of fourth partial electrodes each extending in a direction parallel to the end
surface.
[Claim 13]
The display unit according to claim 12, wherein the plurality of fourth
electrodes are arranged with a pitch corresponding to a pixel pitch in a direction
intersecting the end surface on the display panel.
[Claim 14]
The display unit according to claim 12, wherein the drive section applies a
same voltage to all the fourth partial electrodes in performing the three-dimensional
display.
[Claim 15]
The display unit according to claim 12, wherein the drive section sequentially
drives the plurality of fourth partial electrodes by every predetermined unit within one
frame in performing two-dimensional display.
[Claim 16]
The display unit according to claim 12, wherein the drive section applies a
voltage to the plurality of fourth partial electrodes in two-dimensional display, the
voltage having a frequency, a voltage value, or a duty ratio corresponding to a distance
from the light source.
[Claim 17]
The display unit according to claim 6, wherein
the second electrode includes a plurality of fifth partial electrodes each
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extending in the first direction and each having a strip shape or a step shape, and
the plurality of fifth partial electrodes and the plurality of first partial electrodes
are overlapped with each other.
[Claim 18]
The display unit according to claim 7, wherein an electrode width of the third
partial electrodes is smaller than an electrode width of the second partial electrodes.
[Claim 19]
The display unit according to claim 18, wherein, in performing
two-dimensional display, the drive section applies, to the second partial electrodes, a
voltage having a voltage value smaller than a voltage value of a voltage applied to the
third partial electrodes, a voltage having a duty ratio smaller than a duty ratio of the
voltage applied to the third partial electrodes, or a voltage having a frequency smaller
than a frequency of the voltage applied to the third partial electrodes.
[Claim 20]
An illumination device comprising:
a first transparent substrate and a second transparent substrate that are arranged
to face each other with a distance;
a light source configured to apply light to an end surface of the first transparent
substrate or an end surface of the second transparent substrate; and
a light modulation layer provided in a clearance between the first transparent
substrate and the second transparent substrate, the light modulation layer being
configured to exhibit scattering property or transparency to the light from the light
source depending on a magnitude of an electric field, wherein
the light modulation layer includes a first region and a second region, the first
region having optical anisotropy, and relatively high responsiveness to the electric field,
and the second region having optical anisotropy, and relatively low responsiveness to
the electric field, and
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the light modulation layer generates polarized light when the light modulation
layer exhibits the scattering property, the polarized light having a polarization
component mainly in a first direction.