D E S C R I P T I O N
Title of Invention
LIQUID CRYSTAL DISPLAY DEVICE
5 Technical Field
The present invention relates to a liquid crystal display
device.
Background Art
A liquid crystal cell of a general liquid crystal display
10 device has a structure in which a liquid crystal layer is held
by transparent substrates suchas glass substrates. The liquid
crystal display device includes a liquid crystal panel
configured such that a polarizer, or a polarizer and a
retardation plate, are disposed on the front and back of the
15 liquid crystal cell.
In a first example, a liquid crystal display device
includes a backlight unit as a light source on a back surface
of a liquid crystal panel, which is on a side opposite to an
observer. Ina secondexample, aliquid crystal display device
20 makes use of an external light source such as room light, in
addition to a backlight unit.
In a liquid crystal display device which is capable of
performing three-dimensional image display, and a liquid
crystaldisplaydevicewhichis capableofcontrollingaviewing
25 angle, a liquid crystal panel which makes use of a backlight
unit or an external light source is configured to control,
according to purposes of display, an emission angle of light
whichis emittedtotheoutside froma front surfaceofthe liquid
crystal panel, which is on an observer side.
Various display methods are known for liquid crystal
display devices, or display devices, which are capable of
5 performing three-dimensional image display. These display
methods include methods using glasses, and methods not using
glasses. The methods using glasses include an anaglyphmethod
which makes use of a difference in color, or a
polarization-glasses method which makes use of polarization.
10 In the method of using glasses, it is necessary for an observer
towearpurpose-specific glasses atatime of three-dimensional
image display, and this is troublesome. In recentyears, there
has been an increasing demand for methods which require no
glasses.
15 Inorder to adjust the angle of light which is emitted from
the liquid crystal panel to a single observer or plural
observers (hereinafter, in some cases, "single observer" and
"plural observers" are referred to as "two-view type" and
"multi-view type", respectively) , a study has been made of a
20 technique of providing an optical control element on the front
surface or back surface of the liquid crystal panel.
There is a case in which the optical control element is
used in a liquid crystal display device which is capable of
performing three-dimensional image display and requires no
25 glasses.
An example of the optical control element is a lenticular
lens which is configured such that optical lenses are arranged
two-dimensionally, and realizes regular refraction. The
lenticular lens is used such that a transparent resin or the
like is processed in a sheet shape and attached to the front
surface or back surface of a liquid crystal display device.
5 Patent document 1 (Japanese Patent No. 4010564) and patent
document 2 (Japanese Patent No. 4213226) disclose
three-dimensional image display techniques using lenticular
lenses (lenticularscreens). Patentdocuments 3to8 (Jpn. Pat.
Appln. KOKAI Publication No. 2010-506214, Jpn. Pat. Appln.
10 KOKAI Publication No. 2010-524047, Jpn. Pat. Appln. KOKAI
Publication No. 2010-541019, Jpn. Pat. Appln. KOKAI
PublicationNo. 2010-541020, Japanese Patent No. 4655465, and
Japanese Patent No. 3930021) disclose prism sheets including
convex lenses.
15 The relationship between various arrangements of pixels
(color pixels) of color filters and light-ray control elements
(lenticular sheets) includingapertureportions ina direction
of the arrangement is disclosed in patent document 9 (Jpn. Pat.
Appln. KOKAI Publication No. 2008-249887).
20 In addition, a technique of successively disposing color
filters of the same color in a lateral direction is disclosed,
for example, in Claim 1 of patent document 10 (Jpn. Pat. Appln.
KOKAI Publication No. 2009-3002).
Summary of Invention
25 Technical Problem
In the above-described patent documents 1-8, lenticular
lenses are used. Patent document 1 discloses a technique in
which a display element (a pixel or a sub-pixel) is formed in
a parallelogrammatic shape or a triangular shape, or a display
element is disposed with an offset, thereby substantially
providing an angle between a pixel (or a sub-pixel) array and
5 a lenticular screen. patent document 1, like patent document
2, discloses a technique of giving a successive (smooth)
horizontalparallaxtoanobserver. Inpatentdocument1, there
is a case in which aliasing occurs in display due to a
substantiallyobliquelydisposedpixelarrayandanedge ofthe
10 lenticular screen crossing this pixel array. Patent document
1 discloses, for example, neither a technique of optimizing an
alignment direction, in which liquid crystal molecules become
line-symmetric, by using a three-dimensional optical control
element, nor a technique of associating a triangular prism and
15 a laterally elongated pixel, and effecting switching between
a three-dimensional image and a two-dimensional image. Nor
does patent document 1 disclose a technique of using liquid
crystal molecules with a negative dielectric constant
anisotropy in a liquid crystal display device for
20 three-dimensional image display.
Patent document2 discloses atechniqueinwhichanoffset
angle is provided between a major axis of a lenticular screen
and a pixel array. In patent document 2, a loss in resolution
of three-dimensional image display is reduced by a lenticule
25 towhichanoffset angle is given, andsmoothdisplay is provided
evenwhen the headof the observermoves (the screen is smoothly
switched). However, in patent document 2, since the edge of
the obliquely disposed lenticular screen crosses the pixel
array, there is a case in which aliasing occurs in display.
Patent document 2 discloses, for example, neither a technique
of optimizing a relationship between an alignment direction,
5 in which liquid crystal molecules become line-symmetric, and
a three-dimensional optical control element, nor a technique
of associating a triangular prism and a laterally elongated
pixel, and effecting switching between a three-dimensional
image and a two-dimensional image. Nor does patent document
10 2 disclose a technique of using liquid crystal molecules with
a negative dielectric constant anisotropy in a liquid crystal
display device for three-dimensional image display.
Inpatent documents 3to6, aliquidcrystalofanoptically
compensated bend (OCB) mode is applied to three-dimensional
15 image display. In patent documents 3 to 6, OCB is explained
merely from the standpoint of a response time of a liquid
crystal, which is necessary for three-dimensional image
display. However, none of patent documents 3 to 6 discloses a
liquid crystal display device which optimizes light
20 distributionbyliquidcrystalmoleculesper se, whichareused
inaliquidcrystalpanel, andenables bright three-dimensional
image display. For example,
none of patent documents 3 to 6 discloses in which direction
OCB liquid crystal molecules are to be arranged with respect
25 to a light distribution angle of a light source for a right-eye
image and a light distribution angle of a light source for a
left-eye image, thereby to optimize three-dimensional image
display for the right eye and left eye. In addition, there is
a case inwhich the OCB liquid crystal has alowerviewing-angle
characteristic than IPS (a liquid crystal panel of a lateral
electric field using horizontally aligned liquid crystal
5 molecules) or VA (a liquid crystal panel of a vertical electric
fieldusingvertically alignedliquid crystalmolecules) . The
OCB liquid crystal requires, each time the panel is activated,
a transition operation from a splay alignment, which is an
initial alignment, to a bend alignment at a time of driving.
10 Thus, there is a case in which the OCB liquid crystal is not
preferable for a liquid crystal display device for small-sized
mobile equipment.
Eachofpatentdocuments 3 to 7 discloses a double-surface
prism sheet having a cross-sectional shape as disclosed in
15 patent document 8. A liquid crystal display device of each of
patent documents 3 to 7 performs three-dimensional image
display by using light sources provided on both sides of the
backlight unit. However, likepatentdocument8, noneof patent
documents 3 to 7 discloses a measure for eliminating moire due
20 to interference between the prism sheet and the liquid crystal
panel, which tends to occur in three-dimensional image display.
Furthermore, none of patent documents 3 to 7 discloses a liquid
crystal display device which optimizes light distribution by
liquidcrystal molecules per se, whichareprovidedinaliquid
25 crystal panel, and enables bright three-dimensional image
display and two-dimensional image display.
Patent document 8 discloses a double-surface prism sheet
which includes a cylindrical lens row that is parallel to a
triangular prism row, with a focus position of the cylindrical
lens agreeing with an apex of the prism. FIG. 1 or FIG. 2 of
patent document 8 illustrates a technique of effecting
5 three-dimensional image display by using this double-surface
prism sheet and both-side light sources provided on the
backlight unit. However, in the technique of patent document
8, it is difficult to eliminate moir6 due to interference
between the cylindrical lens row and the liquid crystal panel,
10 which tends to occur in three-dimensional image display. In
addition, patent document 8 does not disclose a liquid crystal
display device which optimizes light distribution by liquid
crystal molecules per se, which are used in the liquid crystal
panel, and enables bright three-dimensional image display and
15 two-dimensional image display. Patent document 8 neither
takes into account the matching between a color filter, which
is generally used in a color liquid crystal display device, and
the double-surface prism sheet, nor discloses the relationship
in correspondency between the double-surface prism sheet and
20 laterally elongated pixel. Furthermore, patent document 8
does not disclose optimization from the standpoint of the
alignmentofliquidcrystalmoleculesusedintheliquidcrystal
panel or the liquid crystal operation.
Patent document 9 discloses a combination between a
25 light-ray control element, which is a lenticular sheet, and
arrangements of colorpixels. However, patent document 9 does
not disclose aliquidcrystaldisplaydevice inwhichelongated
color pixels are formed in a direction in which the two eyes
of the observer are disposed, one active element is provided
in one color pixel, and, when a liquid crystal layer is driven
byactiveelementsofneighboringcolorpixels, tilt directions
5 of liquid crystal molecules become line-symmetric between
laterally neighboring pixels, with respect to the center axis
in the vertical direction of the two neighboring pixels. In
addition, patent document 9 does not disclose a technique in
which a picture element at a time of three-dimensional image
10 display is composed of two red pixels, two green pixels and two
blue pixels. Besides, patent document 9 does not disclose a
liquid crystal display device including, on that surface of an
array substrate which is opposite to a liquid crystal layer,
an edge-lit-type light guide including a solid-state
15 light-emission element array, and a unit for causing the
solid-state light-emission element to emit light by applying
a voltage to the solid-state light-emission element in
synchronism with a video signal and an operation of liquid
crystal molecules.
20 Patent document 10 discloses a technique in which color
elements (color pixels) of the same color are arranged in a
long-side direction of a display area and the color elements
are arranged in stripes. However, patent document 10 does not
disclose a technique of displaying a three-dimensional image
25 by using a lenticular lens, for example, by using a liquid
crystal alignment which is line-symmetric with respect to the
long-side direction. Patent document 10 neither takes into
account the synchronism with the solid-state light-emission
element andthevideo signal, norrelatestoathree-dimensional
image display technique.
As regards the display of a three-dimensional image, an
5 improvement in display quality is desired. However, none of
patent documents 1to 10 discloses atechnique of line-symmetry
driving the liquid crystal layer by active elements, the
laterallyelongatedpixels agreeingwiththe directioninwhich
the two eyes of the observer are disposed and the driving of
10 the liquid crystal, or the optimal configuration of the
lenticular lens and the solid-state light-emission element.
The present invention has been made in consideration of
the above circumstances, and the object of the invention is to
provide a liquid crystal display device for eliminating moire
15 which is incidental display, and for
more brightly and effectively realizing three-dimensional
display and two-dimensional display.
Solution to Problem
In the embodiment, a liquid crystal display device
20 includes anarray substrate, acolor filter substrate, aliquid
crystal layer, a backlight, and a controller. The array
substrate includes a plurality of pixel electrodes
corresponding to a plurality of pixels arranged in a matrix.
The color filter substrate is opposed to the array substrate
25 and includes color filters corresponding to the plurality of
pixels. The liquid crystal layer is'providedbetweenthe array
substrate and the color filter substrate. The backlight unit
is provided on a back surface side of the array substrate, the
back surface side being opposite to a liquid crystal layer side
ofthearraysubstrate. Thecontroller is configuredtocontrol
an application timing of a liquid crystal driving voltage to
5 the pixel electrodes, and a light emission timing of the
backlight unit. Thepluralityofpixels are configuredtoeach
have a shape which is elongated in a lateral direction, and
configured such that identical colors are arranged in the
lateral direction, and different colors are arranged in a
10 vertical direction. Pixels neighboring in the lateral
direction of the plurality of pixels have shapes of
line-symmetry with respect to a center line of the neighboring
pixels. Liquid crystal molecules of the neighboring pixels
tilt in directions of the line-symmetry with respect to the
15 center line when the liquid crystal driving voltage is applied
to the pixel electrodes corresponding to the neighboring
pixels.
Advantageous Effects of Invention
Intheembodiment oftheinvention, displaynon-uniformity
20 such as moire can be eliminated, a three-dimensional image with
a high display quality can be displayed, three-dimensional
display and two-dimensional display can be switched, and
three-dimensional display and two-dimensional display can be
more brightly and effectively realized.
25 Brief Description of Drawings
FIG. 1 is a cross-sectional view illustrating an example
of a liquid crystal display device according to a first
embodiment.
F I G . 2 is a plan view illustrating an example of a
cylindrical lens and a triangular prism of an optical control
element according to the first embodiment.
5 F I G . 3 is a plan view illustrating an example of a color
filtersubstrateoftheliquidcrystaldisplaydeviceaccording
to the first embodiment.
F I G . 4 is a cross-sectional view illustrating an example
of the liquid crystal display device according to the first
10 embodiment.
F I G . 5 is a cross-sectional view illustrating an example
of a liquid crystal operation and emission light at a time when
aliquidcrystaldrivingvoltageis appliedtoapixelelectrode
of one of two neighboring pixels.
15 F I G . 6 is a cross-sectional view illustrating an example
of the liquid crystal operation and emission light at a time
when a liquid crystal driving voltage is applied to a pixel
electrode of the other of the two neighboring pixels.
F I G . 7 is a cross-sectional view illustrating an example
20 of the liquid crystal operation and emission light at a time
whenaliquidcrystaldrivingvoltageisappliedtothethepixel
electrodes of the two neighboring pixels.
F I G . 8 is a plan view illustrating an example of a shape
of pixel electrodes of two neighboring pixels of the liquid
25 crystal display device according to the first embodiment.
F I G . 9 is a cross-sectional view illustrating a first
example of flaw lines formed on the pixel electrode.
FIG. 10 is a cross-sectional view illustrating a second
example of the flaw lines formed on the pixel electrode.
FIG. 11 is a cross-sectional view illustrating a third
example of the flaw lines formed on the pixel electrode.
5 FIG. 12 is a cross-sectional view illustrating an example
of a liquid crystal display device according to a second
embodiment.
FIG. 13 is a plan view illustrating an example of a color
filter substrate of the liquidcrystal display device according
10 to the second embodiment.
FIG. 14 is a plan view illustrating an example of a shape
of pixel electrodes of two neighboring pixels of the liquid
crystal display device according to the second embodiment.
FIG. 15isaplanviewillustratinganexampleofthe shape
15 of pixel electrodes of plural pixels and tilt directions of
liquid crystal molecules in the liquid crystal display device
according to the second embodiment.
FIG. 16 is a cross-sectional view illustrating an example
of synchronization between a pixel electrode of one of two
20 neighboring pixels and a solid-state light emission element.
FIG. 17 is a cross-sectional view illustratinganexample
of synchronization between a pixel electrode of the other of
the two neighboring pixels and a solid-state light emission
element.
25 Description of Embodiments
Embodimentsoftheinventionwi11bedescribedhereinafter
with reference to the accompanying drawings. In the
description below, identical or substantially identical
functions andstructural elements are denotedbylike reference
numerals, andadescriptionthereof is omitted, oradescription
is given only where necessary.
5 In the embodiments below, only characteristic parts will
be described, and a description is omitted of parts which are
not different from structural elements of ordinary liquid
crystal display devices.
In the embodiments below, a pixel may be a sub-pixel. By
10 wayof example, adisplayunit of aliquidcrystaldisplaydevice
isassumedtobeapictureelementwhichiscomposedof sixpixels
includingtwo redpixels, two greenpixels and two blue pixels.
However, the number of pixels included in the picture element
may be freely changed.
15 In the embodiments below, a direction of arrangement of
pixels, which is parallel to a direction of disposition of the
right and left eyes of an observer is defined as a lateral
direction, and a direction of arrangement of pixels, which is
perpendicular to this lateral direction, is defined as a
20 vertical direction.
A color pixel has a shape which is long in the lateral
direction. In the description below, there is a case in which
the lateral direction is described as a pixel longitudinal
direction. The color pixel has a shape which is short in the
25 vertical direction. In the description below, there is a case
in which the vertical direction is described as a pixel
transverse direction.
In the description below, there is a case in which two
pixels of the same color are described as a pair. In addition,
in the picture element including sixpixels, it is assumedthat
two pixels of the same color are arranged in the lateral
5 direction, and pixels of three different colors are arranged
in the vertical direction.
[First Embodiment]
FIG. 1 is a cross-sectional view illustrating an example
of aliquid crystal display device according to the embodiment.
10 FIG. 1 shows a cross section in the lateral direction.
A liquid crystal display device 1 includes, as basic
structural elements, a liquid crystal panel 2, polarizers 3,
a backlight unit 4, and a controller 12. The polarizer 3 may
be formed by attaching a retardation plate.
15 In each of the embodiments below, a pair of polarizers 3
may be configured as crossed Nicols. In addition, the
absorptionaxes ofthepairedpolarizers 3 maybemadeparallel,
and the liquid crystal display device 1 may include a spiral
element between one of the polarizers 3 and the liquid crystal
20 panel 2, the spiral element being configured to convert first
linearly polarized light of this one of the polarizers 3 to
second linearly polarized light which is perpendicular to the
first linearly polarized light.
The liquid crystal panel 2 includes a color filter
25 substrate 5, an array substrate 6 and a liquid crystal layer
7. The color filter substrate 5 and the array substrate 6 are
opposedtoeachother. The liquidcrystal layer7 is interposed
between the color filter substrate 5 and the array substrate
In the present embodiment, a plurality of pixels are
disposed in a matrix.
The liquid crystal panel 2 includes red pixels, green
pixels andbluepixels. Inthe embodiment, eachpixelislonger
in the lateral direction than in the vertical direction, when
viewed in plan.
The lateral direction, as described above, is the
PO direction in which the right eye 81 and left eye 82 of the
observer are disposed. In the embodiment, it is assumed that
neighboringpixels ofthe same colorarearrangedinthe lateral
direction (a horizontal direction in a lateral-directional
crosssectionof FIG. 1). Thepolarizers3, retardationplates
15 (not shown) , etc . are provided on a front surf ace (a plane on
the observer side) side and a back surface (a plane on a side
opposite to the observer) side of the liquid crystal panel 2.
The backlight unit 4 is provided on the back surface of
the liquid crystal panel 2 (the back surface side of the array
20 substrate 6, which is opposite to the liquid crystal layer 7
side) via the polarizer 3. The backlight unit 4 includes, as
basic structuralelements, solid-state light emissionelements
91, 92, suchas LEDs (light-emittingdiodes),a noptical control
element 101 which is an array of triangular prisms, an optical
25 control element 102 which is an array of cylindrical lenses,
and a reflection plate 11.
The array of cylindrical lenses shown in FIG. 1 has a
longitudinal (longer-side) direction in a direction
perpendicular to the lateral-directional cross section of
FIG. 1. The optical control element 101, which is the array
oftriangularprisms, andtheopticalcontrolelement102, which
5 is the array of cylindrical lenses, may be formed of an acrylic
resin or the like, andmay be formed as an integral molded article
of back-to-back attachment.
The pitch of the array of triangular prisms and the pitch
of the array of cylindrical lenses may be in a relationship of
10 1:1, or, as illustrated in FIG. 1, the pitch of the array of
triangular prisms may be set to be finer than the pitch of the
array of cylindrical lenses.
As illustrated in FIG. 2, an angle 8 is provided between
a longitudinal axis of the cylindrical lens and a longitudinal
15 axis of the triangular prism.
The plural triangular prisms have an angle 8 to the
vertical direction. The plural triangular prisms are arranged
with a fine pitch. The angle 8 may be set in a range of, e.g.
3 O to 42O. The angle 8 may be greater than this range. The
20 angle 8 is set at such an angle as not to interfere with the
optical axis of the polarizer or liquid crystal alignment.
The backlight unit 4 may include, for example, a diffusion
plate, a light guide plate, a polarization split film, and a
retroreflectionpolarizationelement, but these components are
25 omitted in FIG. 1.
The solid-state light emission element 91, 92 may be, for
instance, a white LED which emits white light including three
wavelengths of red, green and blue in the light emission
wavelength range. The solid-state light emission element 91,
92 maybe, for instance, apseudo-white LEDinwhichaGaN-based
blue LED and a YAG-based phosphor material are combined. In
5 order toenhance colorrenderingproperties, anLEDwithamajor
peakof one color ormore, suchas aredLED, maybeusedtogether
withapseudo-whiteLED. For example, usemaybemadeof alight
source in which red and green phosphors are stacked on a blue
LED.
10 Thebacklightunit4mayincludeapluralityof solid-state
light emissionelements 91andapluralityof solid-state light
emission elements 92. In this case, the plurality of
solid-state light emission elements 91 and the plurality of
solid-state light emission elements 92 may include LEDs which
15 individuallyemitanyone of red, greenandblue. Theplurality
of solid-state light emission elements 91 and the plurality of
solid-state light emission elements 92 may include LEDs which
emit light of an ultraviolet range, or may include LEDs of an
infrared range.
20 The controller 12 executes various control processes in
the liquid crystal display device 1. For example, the
controller 12 controls the timing of application of a liquid
crystal driving voltage to pixel electrodes 221, 222, and the
timing of light emissionofthe backlightunit4. For example,
25 the controller 12 realizes three-dimensional image display by
synchronizing and controlling the timing of light emission of
the solid-state light emission elements 91, 92, and the timing
of application of a driving voltage of the liquid crystal layer
7, basedona right-eyevideo signalandaleft-eyevideo signal.
In the meantime, the liquid crystal display device 1 may
include a light reception element 13. In this case, the light
5 receptionelement13 isusedfordatainputbyanopticalsensor.
For example, the light reception element 13 detects
specific-wavelength light which is emitted from a light
emissionelementsuchasanultraviolet-rangeorinfrared-range
LED. The controller 12 detects a position of the
10 light-reception element 13, where specific-wavelength light
hasbeendetected. Inaddition, for example, basedonthe light
detected by the light reception element 13, the controller 12
detectsthepositionoftheobserverorthepositionofapointer
suchas afinger. The light receptionelement13 maybeanoxide
15 semiconductor active element with a transparent channel layer
formedofacompositemetaloxide, ormaybe capableof detecting
light of the ultraviolet range. The light reception element
13 may be an image-pickup element (camera) such as a CMOS or
CCD, which is mounted on the housing of the liquid crystal
20 display device. This light reception element 13 may be used
for biometrics authentication or personal authentication, in
addition to touch sensing and image pickup. In addition, the
light reception element 13 may be, for example, a plurality of
optical sensors which are provided in a matrix on the array
25 substrate 6.
The controller 12 detects, for example, the position of
the observer, based on an output value of the light reception
element 13, and adjusts an emission angle P of emission light
from the solid-state light emission element 91, 92, based on
the position of the observer. Thereby, an emission angle ol to
the two eyes (right eye 81 and left eye 82) of the observer can
5 be adjusted, and the visibility of a three-dimensional image
can be improved.
FIG. 3 is a plan view illustrating an example of the color
filter substrate 5 of the liquid crystal display device 1
accordingtotheembodiment. FIG. 3isafrontviewofthecolor
10 filter substrate 5, and illustrates a state in which the color
filter substrate 5 is viewed from the observer. Incidentally,
in FIG. 3, in order to compare the size of the pixel and the
size of the cylindrical lens, a cross section of the optical
control element 102 including an array of cylindrical lenses
15 is depicted by a broken line as a point of reference.
Each pixel has a laterally elongated shape. In FIG. 3,
eachpixelhas arectangularshapewithlong sides inthe lateral
directionandshort sides inthevertical direction. Twopixels
of the same color are arranged in juxtaposition. A plurality
20 of pixels of the same color are arranged in the lateral
direction, and a plurality of pixels of different colors are
arrangedinthe vertical direction. Thosepixels of the plural
pixels, which neighbor in the lateral direction, have a shape
of line-symmetry with respect to a center line of the
25 neighboring pixels. The plural pixels include a picture
element which is composed of laterally arranged green pixels
G1 and G2, red pixels R1 and R2 and blue pixels B1 and B2.
A black matrix BM partitions the pixels. In FIG. 3, the
black matrix BM is formed between vertically neighboring
pixels, and is not formed between the laterally neighboring
pixels. Specifically, theblackmatrixBMis formedatanupper
5 side and a lower side of each pixel.
Under the color filter substrate 5, the array substrate
6 is provided via the liquid crystal layer 7. In other words,
the color filter substrate 5 and array substrate 6 are opposed.
The liquid crystal layer 7 is provided between the color filter
10 substrate 5 and array substrate 6. The array substrate 6
includes active elements 14a, 14b. As the active element 14a,
14b, for example, a thin-film transistor (TFT) is used.
Incidentally, thearray substrate 6maybeconfiguredtoinclude
some other active element as a light reception element.
15 In the description below, pixels G1 and G2 will be
described as typical examples, but other pixels have the same
features .
A width Lp of two pixels G1 and G2 in the lateral direction
is made to agree with the width of a semicylindrical lens. The
20 pixel G1, G2 may be configured to include a light reception
element 13 used as an optical sensor, in addition to the active
element 14a, 14b which drives the liquid crystal layer 7.
FIG. 4 is a cross-sectional view illustrating an example
of the liquid crystal display device 1 according to the
25 embodiment. FIG. 4 corresponds to an A-A' cross section in
FIG. 3. Plural green pixels G1 and G2 are formed in
juxtapositionin the lateral direction (horizontal direction).
The color filter substrate 5 is configured such that a
black matrix BM, a color filter (color layer) 16, a transparent
resin layer 17, counter-electrodes 181, 182, and an alignment
sustaining layer (or alignment film) 251 are formed on a
5 transparent substrate 15. In the cross section of FIG. 4, the
black matrix BM is not depicted, but the black matrix BM is
formed, for example, between the transparent substrate 15 and
color filter 16. The counter-electrodes 18 are formed of, for
example, transparent, electrically conductive films (ITO).
10 The color filter substrate 5 includes color filters 16
corresponding to the plural pixels. Of the color filters 16,
a green filter is associated with the green pixel, a red filter
is associatedwiththeredpixel, andablue filter is associated
with the blue pixel.
15 In the liquid crystal display device 1, the transparent
substrate 15 side of the color filter substrate 5 faces the
observer, and the alignment sustaining layer 251 side of the
color filter substrate 5 faces the liquid crystal layer 7. In
FIG. 4, polarizers are omitted.
20 For example, in a case where priority is placed on the
contrast in two-dimensional image display rather than in
three-dimensional image display, a black matrix BM in the
vertical direction may be formed, for example, at positions P1
of end portions of a pixel set GS composed of two pixels G1 and
25 G2, and at a position P2 at a central part of the two pixels
G1 and G2. The positions P1, P2 are between the transparent
substrate 15 and color filter 16 in the vertical direction (the
direction of stacking of layers of the liquid crystal panel 2)
of the cross section of FIG. 4.
In order to reduce crosstalk (to reduce the effect on
neighboring pixels) in liquid crystal display,
5 counter-electrodes functioning as common electrodes may be
formedatpositionsP1orP3. ThepositionsP3 are thepositions
of end portions of the pixel set G2 in the lateral direction
and are located between the transparent resin layer 17 and
liquid crystal layer 7 in the vertical direction of the cross
10 section of FIG. 4.
Whenhighresponsivityof aliquidcrystalisnotrequired,
the counter-electrodes 18maybe formedbetweenthetransparent
substrate 15 and color filter 16 as plate-shaped electrodes or
solid electrodes (with no pattern formation). The
15 counter-electrodes 18 may be formed between the color filter
16 and black matrix BM as plate-shaped electrodes or solid
electrodes.
The counter-electrode 181 of the pixel G1 and the
counter-electrode 182 of thepixelG2 are formed symmetric with
20 respect to the center axis of the pixel set GS.
The array substrate 6 is configured such that insulation
layers 20a and 20b, common electrodes 211, 212, an insulation
layer 20c, pixel electrodes 221 and 222, and an alignment
sustaining layer 252 are formed on the transparent substrate
25 19. For example, SiN is used for the insulation films 20a to
20c. The array substrate 6 includes a plurality of pixel
electrodes 221, 222, which correspond to the plural pixels G1,
G2.
In the liquid crystal display device 1, the transparent
substrate 19 side of the array substrate 6 is the back side of
the liquid crystal panel 2, and the alignment sustaining layer
5 252 side of the array substrate 6 faces the liquid crystal layer
7.
The pixel electrode 221 of the pixel G1 and the pixel
electrode 222 of the pixel G2 are formed in line-symmetry with
respect to the center axis of the pixel set GS.
10 Similarly, the common electrode 211 of the pixel GI and
the common electrode 212 of the pixel G2 are formed in symmetry
with respect to the center line of the pixel set GS.
In the present embodiment the electrode configuration of
the pixel set GS is line-symmetric. Specifically, the
15 positions of the electrodes of the two neighboring pixels G1
and G2 are line-symmetric. When a voltage has been applied
between the pixel electrode 221, 222 and the common electrode
211, 212, or between the pixel electrode 221, 222 and the
counter-electrode 181, 182, the inclination of the liquid
20 crystal of the liquid crystal layer 7 in the pixel GS becomes
line-symmetric.
The commonelectrode 211, 212 and the pixel electrode 221,
222 in the same pixel have an overlapping portion with a width
Dl at positions in the lateral direction. This overlapping
25 portion canbe usedas a storage capacitance for liquid crystal
display.
The common electrode 211, 212 includes a protrusion
portion (protrusion electrode) 211a, 212a, with a width D2,
which protrudes from the pixel electrode 221, 222 toward the
end portion side of the pixel set GS in the lateral direction.
The protrusion portions 211a, 212a protrude in opposite
5 directions.
The common electrodes 211, 212 and pixel electrodes 221,
222 are formed of, for example, transparent, electrically
conductive films.
The common electrodes 211, 212, which are included in the
10 laterally neighboring pixels, respectively, have shapes of
line-symmetry with respect to the center line of the laterally
neighboring pixels GI, G2.
The liquid crystal layer 7 includes liquid crystal
molecules L1 to L12 with initial vertical alignment. Each of
15 the liquidcrystalmolecules LltoL12 has anegativedielectric
constant anisotropy.
Ref erring to FIG. 5 to FIG. 7, a description is given of
the operation of the protrusion portion 211a, 212a.
FIG. 5 is a cross-sectional view illustrating an example
20 ofthe liquidcrystaloperationandemissionlight231atatime
when a liquid crystal driving voltage is applied to the pixel
electrode 221 of one of the two neighboring pixels.
In FIG. 5, the active element 14a applies a voltage to the
pixel electrode 221. Then, an electric field from the pixel
25 electrode 221tothe commonelectrode 211occurs. Inaddition,
an oblique electric field from the pixel electrode 221 to the
counter-electrode 181 and counter-electrode 182 occurs. The
liquid crystal molecules L1 to L11 with initial horizontal
alignment tilt in a direction of an arrow 241, in a manner to
become perpendicular to electric force lines generated by
applying the voltage to the pixel electrode 221.
5 By this liquid crystal operation, leftward emission light
231is emitted. As describedabove, the angle cc of the emission
light 231 is adjusted by the optical control element 101, 102.
The liquid crystal molecule L1 on the protrusion portion
211atilts greatlyandquickly, basedona substantially strong
10 electric field from the edge portion of the pixel electrode 221
toward the common electrode 211a.
With the tilt of the liquid crystal molecule L1 as a
trigger, the liquid crystal molecules L2 to L11 tilt
successively and instantaneously.
15 Inthepresent embodiment, evenwhenthevoltageisapplied
to the pixel electrode 221 of the pixel GI, the liquid crystal
L7 to L11, which is disposed in the neighboring pixel G2, can
be tilted, and bright three-dimensional image display can be
realized.
FIG. 6 is a cross-sectional view illustrating an example
ofthe liquidcrystal operationandemission light232 atatime
when a liquid crystal driving voltage is applied to the pixel
electrode G2 of the other of the two neighboring pixels.
In FIG. 6, the active element 14a applies a voltage to the
25 pixel electrode 222. Then, an electric field from the pixel
electrode 222 tothe commonelectrode 212 occurs. Inaddition,
an oblique electric field from the pixel electrode 222 to the
counter-electrode 182 and counter-electrode 181 occurs. The
liquid crystal molecules L12 to L2 with initial horizontal
alignment tilt in a direction of an arrow 242, in a manner to
become perpendicular to electric force lines generated by
5 applying the voltage to the pixel electrode 222. The tilt
direction of the liquid crystal molecules L12 to L2 in FIG. 6
is opposite to the tilt direction of the liquid crystal
molecules L1 to L11 in FIG. 5, and is in line-symmetry with
respect to the center axis of the pixels GI, G2.
10 By this liquidcrystal operation, rightwardemission light
232 is emitted. As describedabove, the angle a of the emission
light 232 is adjusted by the optical control element 101, 102.
The liquid crystal molecule L12 on the protrusion portion
212atilts greatlyandquickly, basedona substantially strong
15 electric field from the edge portion of the pixel electrode 222
toward the common electrode 212a.
With the tilt of the liquid crystal molecule L12 as a
trigger, the liquid crystal molecules L11 to L2 tilt
successively and instantaneously.
Inthepresent embodiment, evenwhenthevoltage is applied
to the pixel electrode 222 of the pixel G2, the liquid crystal,
L2 to L6, which is disposed in the neighboring pixel GI, can
be tilted, and bright three-dimensional image display can be
realized.
Byexecuting, insynchronism, the liquidcrystal operation
illustrated in FIG. 5 and FIG. 6 and the light emission of the
solid-state light emission elements 91 and 92, it is possible
to perform three-dimensional image display or to display
different images in the direction of the right eye 81 and in
the direction of the left eye 82.
FIG. 7 is a cross-sectional view illustrating an example
5 of the liquid crystal operation and emission light 231, 232 at
a time when a liquid crystal driving voltage is applied to the
pixel electrodes 221, 222 of the two neighboring pixel G1 and
In this embodiment, if a liquid crystal driving voltage
10 is applied to the pixel electrodes 221 and 222 corresponding
totheneighboringpixelGlandG2, the liquidcrystal molecules
of the neighboring pixels G1 and G2 tilt in line-symmetric
directions with respect to the center axis.
By applying a voltage to the pixel electrodes 221 and 222
15 of the two neighboring pixel G1 and G2, bright two-dimensional
image display with a large viewing angle can be realized.
In this manner, the liquid crystal display device 1
according to the embodiment can very easily effect switching
between a three-dimensional image and a two-dimensional image.
20 In the present embodiment, the description has been given
by using liquid crystal molecules L1 to L12 with negative
dielectric constant anisotropy. However, this embodiment is
similarly applicable to liquid crystal molecules with positive
dielectric constant anisotropy. In the case where liquid
25 crystal molecules withpositive dielectric constant anisotropy
are applied, it is assumed that the liquid crystal molecules
have initial horizontal alignment. If a driving is applied,
liquid crystal molecules, whose longitudinal direction is
parallel to the substrate plane, rise in a direction
perpendicular to the substrate plane.
As the liquid crystal material, for example, a liquid
5 crystal material including fluorine atoms in a molecular
structure (hereinafter referred to as "fluorine-based liquid
crystal") is preferable. The fluorine-basedliquidcrystal is
lowinviscosityanddielectric constant, and is small inamount
of taken-in ionic impurities. In the case where the
10 fluorine-based liquid crystal is used as the liquid crystal
material, the degradation in capability, such as a decrease in
voltageretentionratioduetoimpurities, is small, anddisplay
non-uniformityanddisplayimagepersistencecanbesuppressed.
As the liquid crystal with negative dielectric constant
15 anisotropy, for example, a nematic liquid crystal having a
birefringence index of about 0.1 in the neighborhood of room
temperature can be used. As the liquid crystal with positive
dielectric constant anisotropy, various liquid crystal
materials are applicable. In a liquid crystal display device
20 forwhichahighresponsivity, rather thansuppression inpower
consumption, is required, a liquid crystal having a large
dielectric constant anisotropy may be used. The thickness of
the liquid crystal layer 7 is not particularly limited. In the
embodiment, And of the liquid crystal layer 7, which is
25 effectively applicable, is, for example, in a range of about
300 nm to 500 nm. In a case where formation of a pretilt angle
to the alignment sustaining layer 251, 252 is performedby also
using, for example, exposure by ultraviolet, the horizontal
alignment requires alarge exposureamount, andconversely, the
vertical alignment requires a small exposure amount. Thus,
fromthe standpoint ofthe alignment treatment, aliquidcrystal
5 with vertical alignment is preferable.
FIG. 8 is a plan view illustrating an example of a shape
of pixel electrodes of two neighboring pixels of the liquid
crystal display device according to the first embodiment.
A plurality of flaw lines F are formed on that surface of
10 the pixel electrode 221, 222, which is located on the liquid
crystal layer 7 side. The longitudinal direction of the flaw
lines F is parallel to the long sides of the pixel. The length
of the flaw line F in the longitudinal direction is Len.
By forming the flaw lines F on that surface of the pixel
15 electrode 221, 222, which is locatedon the liquidcrystal layer
7 side, display non-uniformity in the pixel G1, G2 can be
reduced, liquid crystal molecules can be tilted quickly, and
responsivity is enhanced.
The transverse directionofthe flaw line Fis the vertical
20 direction. The width of the flaw line F in the vertical
direction is FI.
The interval (space width) of plural flaw lines F in the
vertical direction is Fs.
In the case where the width of the pixel electrode 221,
25 222 in the vertical direction exceeds 3 pm, or in the case where
the pixel electrode 221, 222 is formed with a rough pitch and
alargewidthsoastobeadaptivetoalarge-sizedliquidcrystal
display or pixels of 250 ppi (pixel per inch) or less, liquid
crystal molecules can be made easier to tilt, by forming the
flaw lines F on the surface of the pixel electrode 221, 222,
andfluctuationcanbeimpartedtotheliquidcrystalalignment.
5 For example, one or more flaw lines F, each having a width
of 1 pm or less in the vertical direction, are formed on the
surface of the pixel electrode 221, 222. For example, one or
more flaw lines F, each having a width of 1 ym or less in the
lateral direction, are formed on the surface of the pixel
10 electrode 221, 222. Flaw lines F are formed on that surface
of the pixel electrode 221, 222, which is located on the liquid
crystal layer 7 side, and it should suffice if a texture
depending on the flaw lines F occurs on that surface of the
alignment sustaining layer 252 formed on the pixel electrode
15 221, 222, which is located on the liquid crystal layer 7 side.
For example, in the case where the pixel electrode 221,
222 is formed of a transparent, electrically conductive film,
the flaw line F may be formed by performing slight etching in
a line shape, with a depth of 20 nm to 40 nm and a width of 0.5
20 pmto 2 pm, on the surface of the pixel electrode 221, 222 having
a thickness of 150 ym. For example, by forming the alignment
sustaining layer 252 with a small thickness of about 50 nm on
the pixel electrode 221, 222, the texture of the flaw line F
is expressed on the surface of the alignment sustaining layer
25 252. The depth of the flaw line F, which is formed in the
insulation layer 20c by slight etching may be in a range of
between 50 nm and less thanl.O pm. Inapart inwhich the pixel
electrode 221, 222 and the common electrode 211, 212 do not
overlap, whenviewedinplan, aspacemaybe formedinaflaw-line
shape (slit shape) with a depth substantially corresponding to
the thickness of the pixel electrode 221, 222. A taper may be
5 formed in the flaw line F, when viewed in cross section. The
width of a bottom part of the flaw line F formed by etching or
the like should preferably be 1 pm or less. The space width
Fs between plural flaw lines F may be set at about 2 pm to 8
pm-
10 FIG. 9 is a cross-sectional view illustrating a first
example of a formation method of flaw lines F.
In FIG. 9, slight etching is performed on the pixel
electrode 221, 222 which is formed by a transparent conductive
film (ITO) , and flaw lines F are formed on an upper surface of
15 the pixel electrode 221, 222.
FIG. 10 is a cross-sectional view illustrating a second
example of the formation method of flaw lines F.
In FIG. 10, a flaw line-shaped insulation pattern is
formed in advance on the insulation layer 20c of the array
20 substrate 6, andthepixelelectrode221, 222 is formedthereon.
Thereby, flaw lines Fare formedonanupper surfaceofthepixel
electrode 221, 222.
FIG. 11 is a cross-sectional view illustrating a third
example of the formation method of flaw lines F.
In FIG. 11, the surface of the insulation layer 20c of the
array substrate 6 is etched, and flaw line-shaped recess
portions are formed. Thereafter, by stacking a transparent
conductive film, a pixel electrode with flaw lines F is formed.
If an oblique electric field is formed between the pixel
electrode 221, 222 andthe counter-electrode181, 182, auniform
"tilt" of liquid crystal molecules canbe obtained on the pixel
5 electrode 221, 222 by the flaw lines F formed on the pixel
electrode 221, 222 inparallel to the pixel electrode 221, 222.
In the case of a pixel electrode 221, 222 with a large width,
onwhichno flaw line Fis formed, a"non-uniform tilt" of liquid
crystal molecules occursbetweenacornerportionandacentral
10 portion of the pixel electrode 221, 222 as viewed in plan, and
light/darkdisplayornon-uniformityintransmittancet ends to
occur on thepixel electrode 221, 222 or within the pixel. Such
light/dark display or non-uniformity causes a decrease in
transmittance of the pixel. In addition, liquid crystal
15 molecules disposed above the flaw lines F are, while being in
vertical alignment, affected by the texture expressed by the
flaw lines, and the liquid crystal molecules are easily titled
by a low voltage, and high-speed driving becomes easier. The
number of flaw lines F, which are formed, may be one or plural,
20 in accordance with the width of the pixel electrode 221, 222.
When the width of the pixel electrode 221, 222 is 3 pm or less
and is small, the flaw line F may not be formed.
In thepresent embodiment, the counter-electrode 181, 182
is a transparent electrode, and may be formed in a stripe
25 pattern. For example, in order to detect touching of a finger
or the like, an electrostatic capacitance, which is formed
between the counter-electrode 181, 182 with the stripe pattern
and the common electrode 211, 212 of the array substrate 6, may
be detected. Thereby, the liquid crystal display device 1 can
be provided with a touch sensing function.
The alignment sustaining layer 251, 252 is formed, for
5 example, by formingaphotosensitive alignment film inadvance,
and radiating light, after the formation of a liquid crystal
cell, while applying a voltage between at least two electrodes
of the pixel electrode 221, 222, the common electrode 211, 212,
and the counter-electrode181, 182, thereby impartingapretilt
10 formation function to the photosensitive alignment film. The
method, inwhichaphotosensitive alignment film is formedand,
after the formation of a liquid crystal cell, a voltage is
applied and a pretilt is formed in an alignment film, is also
calledFPAor PSA. However, thepretilt formation functioncan
15 beimpartedmore easilythaninFPAor PSA, by formin ginadvance
the above-described flaw lines F on the surface of the pixel
electrode 221, 222 andusingthealignmentsustaininglayer251,
252 in which the pretilt is uniformly formed in the
photosensitive alignment film.
20 The alignment sustaining layer 251 is formed directly or
indirectlyonthe counter-electrode181, 182 in the color filter
substrate 5. The alignment sustaining layer 252 is formed
directly or indirectly on the pixel electrode 221, 222 in the
array substrate 6.
The alignment sustaining layer 251, 252 may be an organic
film to which a pretilt angle is imparted by, e.g. light
irradiationunder an electric field. The alignment sustaining
layer251, 252 is formedatapositionincontact withthe liquid
crystal layer 7. The alignment sustaining layer 251, 252 is
formedbyimpartingapretilt formation function forthe liquid
crystal to an alignment film which vertically aligns liquid
5 crystalmolecules, by radiation rays suchas light or heat rays,
or by radiation rays given under an electric field. As the
radiationrays, ultravioletmaybeused. Thepretilt formation
function by the alignment sustaining layer 251, 252, which is
formedonaplanar surfaceportioninaunitsub-pixel or aunit
10 pixel, imparts a pretilt angle to the liquid crystal,
practically, in a range of O.1° - l.EjO, and more preferably,
inarange of O.1° - lo. Since the liquidcrystal displaydevice
1 utilizes an oblique electric field, the liquid crystal
molecules of the liquid crystal layer 7 can smoothly be driven
15 even by a small pretilt angle of less than lo. In a
normally-black vertical-alignment liquid crystal, as the
pretilt angle given by the alignment sustaining layer 251, 252
becomes smaller, light leakage at a time of black display can
bemorereducedandahighercontrastcanbeobtained. However,
20 in usual cases, in a vertical-alignment liquid crystal with a
small pretilt angle, a liquid crystal driving voltage on a
low-voltage side increases, and reproducibility from black
display to intermediate gradation display decreases.
If the alignment sustaining layer 251, 252 is used, even
25 witha smallpretiltangle, intermediate gradationdisplaywith
a high liquid crystal responsivity can be performed at a low
voltage. In addition, low power consumption can be realized
by low-voltage driving. Incidentally, the pretilt angle
refers to an inclination angle of the major axis of the liquid
crystalmolecule tothe normal directionof the substrate plane
at a time when no liquid crystal driving voltage is applied.
5 Whenthepretiltangle of the vertical alignment liquidcrystal
becomes greaterthan1.5O1 there is atendencythat the contrast
lowers due to light leakage. Accordingly, fromthe standpoint
of the contrast, it is desirable that the pretilt angle be as
small as possible. In the electrode configuration according
10 to this embodiment, a higher liquid crystal responsivity and
smoother intermediate gradation display can be achievedbythe
oblique electric fields produced between the pixel electrode
221, 222 and the protrusion portion 211a, 212a and between the
pixel electrode 221, 222 and the counter-electrode 181, 182.
15 As the alignment film before alignment treatment for
formingthealignmentsustaininglayer221, 222 withthepretilt
angle, use may be made of, for instance, photosensitive
polyorganosiloxane, or a substance includingapolymerbetween
photosensitive polyorganosiloxane and polyamic acid or
20 polyimide . In addition, as the alignment film, use may be made
of a siloxane-basedpolymer representedby siloxane cinnamate.
Besides, as the alignment film, use may be made of a coating
film of, e.g. photosensitive polyimide or a photosensitive
polymerizable liquid crystal material. Furthermore, as the
25 alignment film, use may be made of a photo-alignment film using
an azobenzene derivative, or a photo-alignment film including
polyamic acid having a triple bond in the main chain.
Incidentally, thepre-tilt angle is measuredby, e.g. a crystal
rotation method described in Journal of Applied Physics, Vol.
48, NO. 5, pp. 1783-1792 (1977).
The structure and manufacturing method of the alignment
5 sustaining layer 251, 252 will be described below.
The alignment sustaininglayers (alignment films to which
pretiltanglesaregiven) 251, 252 are formedonthoseelectrode
surfaces of the color filter substrate 5 and array substrate
6, which are located on the side in contact with the liquid
10 crystal layer 7.
In the color filter substrate 5 and array substrate 6, a
vertical alignment agent is printed and vertical alignment
filmsare formed. Forexample, as theverticalalignment agent,
use is made of a mixture of photosensitive polyorganosiloxane
15 and polyamic dissolved in advance in a mixture solvent of
n-methyl-2-pyrrolidonea ndbutyl cellosolve. The temperature
for drying after the print is 180°C, and the thickness of each
vertical alignment film is set at, e.g. about 60 nm.
An epoxy adhesive including spherical spacers of 3.6 pm
20 is printed on the color filter substrate 5 as a liquid crystal
sealing portion, a liquid crystal with a negative dielectric
constant anisotropy is dispensed at a center of this color
filter substrate 5, the array substrate 6 is attached so that
no air may enter, and a liquid crystal cell is formed. This
25 liquid crystal cell is once heated, and the liquid crystal is
made isotropic.
Next, while an AC voltage is being applied to the pixel
electrode 221, 222 of the array substrate 6, non-polarized
ultraviolet of 1000 ~ / ims r~ad iated from a normal direction
of a glass plane (a direction perpendicular to a glass plane)
of the transparent substrate 19 on the side opposite to the
5 liquid crystal layer 7. Incidentally, the counter-electrode
181, 182 and the common electrode 211 212 are set at a ground
potential of 0 V.
By themagnitudeof drivingvoltage, themannerof applying
the voltage, the radiation amount of ultraviolet and the
10 simultaneous use of polarized ultraviolet from an oblique
direction, various pretilt angles can be given to the alignment
films, and the alignment sustaining layers 251, 252 can be
formed. In the present embodiment, the pretilt angle of the
alignment sustaining layer 252 on the array substrate 6 is in
15 the range of about 0.4O - O.gO, and liquid crystal molecules
tilt in a direction in which the common electrode 211, 212
protrudes from the pixel electrode 221, 222 in the lateral
direction.
Polarizers are attached to both surfaces of the liquid
20 crystal cell which has been subjected to alignment treatment,
andtheliquidcrystaldisplaydevice1is formed. Inthe liquid
crystal display device 1 according to the embodiment, there is
little light leakage in the normally-black display at a time
when no liquid crystal driving voltage is applied, and good
25 black display can be realized.
In addition, in the liquid crystal display device 1
according to the embodiment, since the oblique electric field
drivingmethodbythepixelelectrode 221, 222, commonelectrode
211, 212 and counter-electrode 181, 182 is applied, good
intermediategradationdisplaycanbeperformedonalowvoltage
side even if the pretilt angle of the liquid crystal layer 7,
5 which is in contact with the alignment sustaining layer 251,
252, is small.
In the manufacture of the alignment sustaining layer 251,
252 of the liquid crystal display device 1 according to the
embodiment, anACvoltageis appliedtothepixelelectrode 221,
10 222, the common electrode 211, 212 and counter-electrode 181,
182 are set at the ground potential of the common potential,
and ultraviolet is radiated. Thereby, the pretilt formation
function is given to the alignment sustaining layer 251, 252.
Themethodof voltageapplication, theamount of light radiation
15 and the wavelength of exposure can properly be adjusted in
accordance with various dimensions of the liquid crystal
display device 1, the material characteristics of the liquid
crystal layer 7 and the alignment film that is used for the
formation of the alignment sustaining layer 251, 252. For
20 example, the AC voltage may be an asymmetric rectangular wave.
In addition, as regards the application of the liquid crystal
driving voltage, various adjustments are possible, such as
setting any one of the pixel electrode 221, 222, common
electrode 211, 212 and counter-electrode 181, 182 in the
25 floating state, or shifting the common potential to a positive
or negative side.
In the liquid crystal display device 1 of the
above-described embodiment, display non-uniformity such as
moire can be eliminated, the display quality of a
three- dimensional image can be enhanced, bright display can be
performed, and easy switching can be made between
5 three-dimensional display and two-dimensional display. These
advantageous effects will be concretely described below.
In the present embodiment, laterally elongatedpixels are
formed. In this structure, a row of green pixels, a row of red
pixels and a row of blue pixels are arranged in the lateral
10 direction.
In ordinary vertically elongated pixels, three kinds of
pixels, namely a red pixel, a green pixel and a blue pixel, are
arranged in the lateral direction. In order to drive active
elements located below the pixels, drivers for sending video
15 signals in the vertical direction are necessary for the three
colors.
By contrast, in the embodiment, since the laterally
elongated pixels of the same color are arranged in the lateral
directionandthethreedifferentcolorsarearrangedinstripes
20 in the vertical direction, the number of drivers of pixels can
bereducedto1/3 fortheordinarypixels, andthe liquidcrystal
panel 2 can be manufactured at low cost. Since the power
consumption of the drivers which handle video signals is high,
the present embodiment can provide the liquid crystal display
25 device 1 with low power consumption.
Inaddition, since thepixel widthinthe lateraldirection
of the pixels of each color in the liquid crystal display device
1 according to the embodiment is laterally large and is fixed,
high-quality display with no color non-uniformity in units of
a picture element can be realized, compared to the case of
vertically elongated, inclined pixels. Furthermore, since
5 thin- f ilm transistors of an oxide semiconductor, which has low
sensitivity in visible light range, can be used as the active
elements 14a, 14b for driving the liquid crystal, the liquid
crystal display device 1 with a fine black matrix BM and a large
aperture ratio can be provided.
10 In this embodiment, displaynon-uniformity suchas moire,
which is a problem in conventional three-dimensional display,
can be eliminated, and, with bright display, switching between
three-dimensional display and two-dimensional display can be
realized by a simple configuration.
15 The liquid crystal display device 1 according to the
embodiment is applicable to display devices which are disposed
onamobilephone, a game console, atabletterminal, anotebook
PC (personal computer), a television, a car dashboard, etc.
Incidentally, as a modification of the embodiment, the
20 liquid crystal display device 1 may further include, in order
to eliminate moire, a plurality of triangular prisms having a
longitudinal directionwhichis substantiallyperpendicular to
the longitudinal direction of the plural triangular prisms.
In addition, for more effective three-dimensional image
25 display, the longitudinal direction of the plural triangular
prisms and the longitudinal direction of the plural
semicylindrical lenses may be made substantially parallel, and
thewidthofthe triangularprismmaybe set at doublethe length
of the pixel in the lateral direction.
The width of the semicylindrical lens may be set at an
integer number of times of the widthof twopixels in the lateral
5 direction.
Another optical control element including an array of a
pluralityof semicylindricallensesmaybe disposedbetweenthe
array substrate 6 and the backlight unit 4, or on that surface
side (observer side) of the color filter substrate 5, which is
10 opposite to the liquid crystal layer 7 side. Furthermore, the
longitudinal direction of the semicylindrical lenses included
in this other optical control element may be set to be
perpendicular to the lateral direction.
[Second Embodiment I
FIG. 12 is a cross-sectionalviewillustratinganexample
of a liquid crystal display device according to the present
embodiment. FIG. 12 is a cross-sectional view in the lateral
direction.
A liquid crystal display device 30 includes, as basic
20 structural elements, a liquid crystal panel 26, polarizers 3,
andabacklight unit 27. Incidentally, like the liquid crystal
display device 1 according to the above-described first
embodiment, the liquid crystal display device 30 may include
a controller 12 and a light reception element 13.
25 Solid-state light emission elements 91, 92 are disposed
at both ends of the backlight unit 27. The polarizer 3 may be
formed by attaching a retardation plate.
The liquidcrystal panel26 is configuredsuchthatacolor
filter substrate 28 andanarray substrate 6 are opposedtoeach
other, andaliquidcrystallayer7isprovidedbetweenthecolor
filter substrate 28 and the array substrate 6. In the liquid
5 crystalpanel26, apluralityofpixels eachhavingalaterally
elongatedshape, whichincluderedpixels, greenpixels andblue
pixels, are arranged in the lateral direction. In this
embodiment, the pixels are arranged in the lateral direction
such that the pixels of the same color neighbor. The polarizer
10 3 and a retardation plate (not shown) are provided on a front
surface and/or a back surface of the liquid crystal panel 2.
The main structure of the liquid crystal display device 30
according to this embodiment is substantially the same as that
of the above-described first embodiment.
15 The liquid crystal display device 30 according to the
embodimenthas twochangepoints fromtheliquidcrystaldisplay
device 1 according to the first embodiment.
The first changepoint is that boththe array of triangular
prisms, which is the optical control element 101, and the array
20 of cylindricallenses, whichistheopticalcontrolelement102,
are perpendicular to the lateral direction and the normal
direction of the liquid crystal panel 26 (i.e. perpendicular
to the cross section of FIG. 12). In addition, both the
triangular prism and the cylindrical lens have the same width
25 as a width Lp of two pixels.
The second change point is that pixels arranged in the
lateral direction are parallelogrammatic with a long side
having an angle y to the lateral direction, and a short side
parallel to the vertical direction. The angle y is set in a
range of, e.g. about 5O to 30°, and is set at, for instance,
about 15O. By forming each pixel arranged in the lateral
5 direction in the parallelogrammatic shape with the angle y,
moire can be reduced.
FIG. 13 is aplanview illustratinganexample of the color
filter substrate 28 of the liquid crystal display device 30
according to the present embodiment. FIG. 13 is a front view
10 of the color filter substrate 28, and illustrates a state in
whichthecolorfiltersubstrate28isviewedfromtheobserver.
In FIG. 13, pixels of the same color neighbor at short
sides ofthepixels in thevertical direction. The arrangement
of pixels in the lateral direction has a repetitive pattern of
15 two pixels of the same color in a V shape. The mutually
neighboringpixels in the lateral direction are symmetric with
respect to the center line. Incidentally, the arrangement of
pixels in the lateral direction may have a repetitive pattern
of two pixels of the same color in an inverted-V shape.
20 Since the pixel has the angle y for reducing moir6 and the
pixels of the same color are arranged in the lateral direction,
three-dimensional image display with less moire and color
non-uniformitycanberealized. Bynot formingtheblackmatrix
BM between the laterally neighboring pixels, bright
25 three-dimensional image display with less color moire can be
realized.
For example, a first picture element is composed of green
pixels G1 and G2, red pixels R1 and R2 and blue pixels B1 and
B2, and a second picture element is composed of green pixels
G3 and G4, red pixels R3 and R4 and blue pixels B3 and B4.
FIG. 14 is a plan view illustrating an example of a shape
5 of pixel electrodes 221, 222 of two neighboring pixels GI, G2
of the liquid crystal display device 30 according tothepresent
embodiment.
Inaddition, FIG. 15 isaplanviewillustratinganexample
of the shape of the pixel electrodes 221, 222 of plural pixels
10 G1 to G4, R1 to R4, and B1 to B4 and tilt directions of liquid
crystal molecules in the liquid crystal display device 30
according to this embodiment.
In FIG. 14 and FIG. 15, parallelogrammatic pixels having
the angle y to the lateral direction, when viewed in plan, are
15 arranged. FIG. 14 illustrates plan-view shapes of the pixels
G1, G2, and FIG. 15 illustrates plan-view shapes of the green
pixels G1 to G4, red pixels R1 to R4, and blue pixels B1 to B4.
Eachof thepixels GltoG4, RltoR4 andBltoB4 is equipped
with an active element 14a or an active element 14b.
20 The active element 14a, 14b is, for example, a thin-film
transistor of an oxide semiconductor having a transparent
channel layer of two ormore kinds of metaloxides. If aliquid
crystal driving voltage is applied to the pixel electrode 221
or pixel electrode 222 of the pixels G1 to G4, R1 to R4 and B1
25 to B4 via the active element 14a, 14b, the liquid crystal on
the pixel electrode 221 or pixel electrode 222 tilts in a
direction of an arrow 311, 312. The arrow 311, 312 has an angle
y to the lateral direction. The arrows 311, 312 are
line-symmetric with respect to the center axis of the
neighboring pixels. Flaw lines F are formed on the surface of
the pixel electrode 221 or pixel electrode 222. By the flaw
5 lines F, high liquid crystal responsivity and uniformity in
display in the pixel can be realized. The flaw lines F can be
formed similarly with the first embodiment.
FIG. 16 is a cross-sectional view illustratinganexample
of synchronization between the pixel electrode 221 of one of
10 two neighboring pixels and the solid-state light emission
element 91.
FIG. 17 is a cross-sectional view illustratinganexample
of synchronizationbetween the pixel electrode 222 of the other
of two neighboring pixels and the solid-state light emission
15 element 92.
FIG. 16 and FIG. 17 illustrate cross sections of the two
pixels G I and G2, and represent the operations for
three-dimensionalimagedisplayoftheopticalcontrolelements
101, 102.
20 Byapplyingtheliquidcrystaldrivingvoltagetothepixel
electrode 221 in FIG. 16, liquid crystal molecules L21, L22 of
the left-side pixel G1 in FIG. 16 tilt. In synchronism with
the application of the voltage to the pixel electrode 221, the
solid-state light emission element 91 is caused to emit light.
25 As illustrated in FIG. 16, the light emitted from the
solid-state light emission element 91 passes through the
triangular prism of the optical control element 101 and the
cylindrical lens of the optical control element 102, and is
emittedtowardtherighteye 81oftheobserveras emissionlight
321. An emission angle a can be set, mainly based on a
distal-end angle r of the triangular prism and a curvature r
5 of the cylindrical prism. For example, by adjusting the
magnitude of the distal-end angle of the triangular prism, the
emission light of the left-side solid-state light emission
element 91 can be emitted to the opposite left eye 81.
Similarly, by applying the liquid crystal driving voltage
10 to the pixel electrode 222 in FIG. 17, liquid crystal molecules
L23, L24 of the right-side pixel G2 in FIG. 17 tilt. In
synchronism with the application of the voltage to the pixel
electrode 222, the solid-state light emission element 92 is
caused to emit light. As illustrated in FIG. 17, the light
15 emitted from the solid-state light emission element 92 passes
through the triangularprismofthe optical control element101
and the cylindrical lens of the optical control element 102,
and is emittedtowardthe left eye 82 ofthe observer as emission
light 322.
20 As has been described above, by providing the angle y to
the lateral direction with respect to the plan-view shape of
the pixel G1, G2, the moir6 in three-dimensional image display
cangreatlybereduced. Furthermore, bynotprovidingtheblack
matrix BM in the vertical direction, the moire due to an
25 alignment error between the pixel and the optical control
element 101, 102 can be reduced. In the case where priority
is to be placed on the contrast at a time of liquid crystal
display, the black matrix BM for partitioning the pixels in the
vertical direction may be provided.
For example, an electrically conductive metal oxide thin
film of, e. g. IT0 or IZO can be used as the material of the pixel
5 electrode 221, 222 andthecommonelectrode211, 212 ofthearray
substrate 6 of the liquid crystal display device 30 according
to the embodiment.
The pixel electrode 221, 222 and the common electrode 211,
212 are electrically insulated by an insulation film 20c in the
10 thickness direction thereof. The thicknesses of the color
filter16, transparent resin layer 17 and insulation layers 20a
to 20c can be adjusted based on the thickness of the liquid
crystal layer 7, dielectric constant, application voltage and
driving condition.
15 In the case where the insulation layers 20a to 20c are
formed of SiNx (silicon nitride), the practical range of film
thickness of the insulation layers 20a to 20c is, for example,
0.1 pm to 1.0 pm. In the liquid crystal display device 30
according to the present embodiment, since an oblique electric
20 field can more effectively be utilized, the range, in which
electric force lines act at a time of driving voltage
application, maybe increase dint he directionof filmthickness
including the liquid crystal layer 7, transparent resin layer
17 and color filter 16. Thereby, the transmittance of light
25 can be increased. In order to increase the transmittance in
this manner, the counter-electrodes 181, 182 may be provided
between the transparent substrate 17 and color filter 16. For
example, Jpn. Pat. Appln. KOKAI Publication No. 2009-105424
discloses a technique of forming signal lines, such as gate
lines and source lines, by a single layer of an aluminum alloy
having a low contact property with IT0 that is an electrically
5 conductive metal oxide. To further stack an insulation layer
on the pixel electrode 221, 222 is preferable since this has
aneffect of reducinganimagepersistence of the liquidcrystal
(the effect of non-uniformity or accumulation of electric
charge) at the time of driving the liquid crystal.
10 The signal lines may be, for example, aluminum lines or
copper lines. In a case where the signal line includes copper,
for example, the signal line may be formed by a multilayer
structure in which copper and titanium are stacked, or a
multilayer structure in which copper, titanium and silicon are
15 stacked. The titanium included in the signal line may be
replaced with, for example, molybdenum, tungsten, or other
high-melting-point metal.
In the case where the active element 91, 92 is a thin-film
transistor of anoxide semiconductor wit ha channel layer which
20 is transparent inavisible range, the linewidthofthepattern
of the light-shield layer, such as the black matrix BM, can be
reduced, andthebrightnessofthe liquidcrystaldisplaydevice
30 can be enhanced. In the case where the thin-film transistor
oftheoxide semiconductor isusedinthe liquidcrystal display
25 device 30, optical alignment can efficiently be performed and
the reliability of the liquid crystal display device 30 can be
enhanced. In a conventional PSA technique using a liquid
crystal to which a photopolymerizable monomer is added, there
is a case in which the reliabilityof the liquid crystal display
device is degraded by a residual non-polymerized monomer or an
insufficientlycuredopticalalignment filmdue toultraviolet
5 shielding by the light-shield portion of the thin-film
transistor that occupies a large area relating to the silicon
semiconductor or the black matrix BM which partitions colored
pixels, or the color filter with poor ultraviolet
transmittance. However, as in the embodiment, by using the
10 thin-filmtransistor ofthe oxide semiconductor, it is possible
to decrease the area of the light-shield portion, to perform
exposureonawidearea, andtogreatlyenhancethe reliability.
Compared to this thin-film transistor of the oxide
semiconductor, a thin-film transistor of a silicon
15 semiconductor has sensitivity to light in a visible range, and
it is thus necessary to light-shield the thin-film transistor
withalargerareabya light-shield layersuchas ablackmatrix
BM .
As the oxide semiconductor, composite metal oxides which
20 are transparent in the visible range are applicable. A
semiconductor material including these metal oxides as
components is an oxide including two or more elements of zinc,
indium, tin, tungsten, magnesium, and gallium. As materials,
for instance, use may be made of zinc oxide, indium oxide,
25 indium-zinc-oxide, tin oxide, tungsten oxide (WO) ,
indium-gallium-zinc-oxide( In-Ga-Zn-O)i,n dium-gallium-oxide
(In-Ga-0), zinc-tin-oxide (Zn-Sn-0), or
zinc-tin-silicon-oxide( ~n-~n-~i-o0r )o,t her materials.
Thesematerials are substantially transparent, and thebandgap
should preferably be 2.8 eV or more, and should more preferably
be 3.2 eV or more. The structure of these materials may be any
5 one of a single crystal, a polycrystal, a microcrystal, a mixed
crystal of a crystalline/amorphous structure, a
nanocrystal-dispersed amorphous structure, and an amorphous
structure. It is desirable that the film thickness of an oxide
semiconductor layer be 10 nm or more. The oxide semiconductor
10 layer is formed by using a method such as a sputtering method,
a pulse laser deposition method, a vacuum evaporation method,
aCVD (ChemicalVaporDeposition) method, anMBE (MolecularBeam
Epitaxy) method, an ink jet method, or a print method.
Preferably, the oxide semiconductor layer is formed by the
15 sputtering method, pulse laser deposition method, vacuum
evaporation method, ink jet method, or print method. As regards
the sputtering method, an RF magnetron sputtering method or a
DC sputtering method is usable, but, more preferably, the DC
sputtering method is used. As a starting material (target
20 material) for sputtering, an oxide ceramic material or a
metallic target material can be used. As regards the vacuum
evaporation, heating evaporation, electron beam evaporation,
and an ion plating method can be used. As the print method,
transfer printing, flexography, gravure printing, and gravure
25 offset printing are usable, but other methods may be used. As
the CVD method, a hotwire CVD method and plasma CVD are usable.
Furthermore, othermethodsmaybeused, suchas amethodinwhich
a hydrate of an inorganic salt (e. g. chloride) is dissolved in
alcohol, etc., andbakedand sintered, thereby forminganoxide
semiconductor.
Next, a description is given of the structures of the
5 thin-film transistor of the oxide semiconductor and the array
substrate 6. As illustratedin FIG. 16, in the array substrate
6, insulation layers 20a, 20b, common electrodes 211, 212, an
insulation layer 20c, pixel electrodes 221, 222, and an
alignment sustaining layer 252 are formed in the named order
10 onatransparent substrate (e.g. glass substrate) 19. Thearray
substrate 6 includes active elements 14a, 14b for applying a
liquidcrystaldrivingvoltagetothepixelelectrodes 221, 222,
andgatelinesandsourcelineswhichareelectricallyconnected
to the active elements 14a 14b.
15 The active element 14a, 14b has, for example, a
bottom-gate-type top contact etch stopper structure.
Alternatively, the active element 14a, 14b may have, for
example, a bottom-gate-type top contact structure excluding an
etch stopper, or a back channel structure. The transistor
20 structure is not limited to the bottom gate structure, and may
be a top gate structure, a double gate structure, or a dual gate
structure.
Inthemanufactureofthe active element14a, 14b, tobegin
with, an IT0 thin film of 140 nm is formed by a DC magnetron
25 sputtering method. Then, the IT0 thin film is patterned in a
desired shape, and a gate electrode and an auxiliary capacitor
electrode are formed. Further, a SiH, thin film of 350 nm is
formed thereon by using a plasma CVD method, with use of SiH,,
NH3 and H2 as a material gas, and thus a gate insulation film
that is a transparent insulation film is formed. In addition,
as a channel layer, an amorphous In-Ga-Zn-0 thin film of 40 nm
5 is formedbyaDC sputteringmethodbyusingan InGaZnOatarget,
and the amorphous In-Ga-Zn-Othin film is patteredinadesired
shape, andthus atransparent channel layer is formed. Further,
an SiON thin film is formed by an RF sputtering method by using
a Si3H4 target while introducing Ar and O2 , and the SiON thin
10 film is patterned in a desired shape, and thus a channel
protection layer is formed. Furthermore, an IT0 thin film of
140 nm is formed by a DC magnetron sputtering method and is
patterned in a desired shape, and a source/drain electrode is
formed.
15 In the liquid crystal display device 30 according to the
above-described embodiment, the same advantageous effects as
with the liquid crystal display device 1 according to the
above-described first embodiment can be obtained.
[Third Embodiment]
In the present embodiment, transparent resins andorganic
pigments, which are used for the color filter substrates 5, 28
according to the above-described first and second embodiments,
will be exemplarily described.
(Transparent resins)
A photosensitive color composition, which is used for
forming the black matrix BM and color filter 16, includes, in
addition to a pigment-dispersed body, a multifunctional
monomer, a photosensitive resin or a nonphotosensitive resin,
apolymerizationinitiator, anda solvent. Organic resins with
high transparency which can be used in the present embodiment,
for instance, a photosensitive resin or a nonphotosensitive
5 resin, are generally referred to as transparent resins.
As the transparent resins, usecanbemadeof thermoplastic
resins, thermosetting resins, or photosensitive resins. As
the thermoplastic resins. for example, use can be made of a
butyral resin. styrene-maleic acid copolymer, chlorinated
10 polyethylene, chlorinated polypropylene, polyvinyl chloride,
vinyl chloride-vinyl acetate copolymer, polyvinyl acetate,
polyurethane resin, polyester resin, acrylic resin, alkyd
resin, polystyrene resin, polyamide resin, rubber resin,
cyclized rubber resin, celluloses, polybutadiene,
15 polyethylene, polypropylene, and polyimi.de. In addition, as
the thermosetting resins, for example, use can be made of an
epoxy resin, benzoguanamine resin, rosin-modifiedmaleic acid
resin, rosin-modified fumaric acid resin, melamine resin, urea
resin, and phenol resin. The thermosetting resin may be
20 produced by a reaction between a melamine resin and a compound
including an isocyanate group.
(Alkali-soluble resins)
For the formation of the light-shield pattern such as the
black matrix BM, the transparent pattern and the color filter,
25 which are used in the present embodiment, it is preferable to
use photosensitive resin compositions which are capable of
patterning by photolithography. It is desirable that these
transparent resins be resins to which alkali-solubility is
imparted. As the alkali-soluble resins, resins including a
carboxyl group or a hydroxyl group may be used, or other resins
may be used. As the alkali-soluble resins, for example, use
5 can be made of an epoxy acrylate resin, novolak resin,
polyvinylphenol resin, acrylic resin, carboxyl
group-containing epoxy resin, and carboxyl group-containing
urethane resin. Of these, the epoxy acrylate resin, novolak
resin and acrylic resin should preferably be used as the
10 alkali-soluble resins, and, in particular, the epoxy acrylate
resin and novolak resin are preferable.
(Acrylic resins)
As typical transparent resins which are applicable in the
embodiment, the following acrylic resins are exemplarily
15 described.
As the acrylic resins, use can be made of polymers which
are obtainedbyusing, as monomers, for instance, (meth)acrylic
acid; alkyl (meth)acrylate suchasmethyl (meth)acrylate, ethyl
(meth)a crylate, propyl (meth)a crylate, butyl (meth)a crylate,
20 t-buthyl (meth) acrylate, benzyl (meth) acrylate, or lauryl
(meth)acrylate; hydroxylgroup-containing (meth)acrylate such
as hydroxyethyl (meth)acrylate or hydroxypropyl
(meth)a crylate; ether group-containing (meth)a crylate such as
ethoxyethyl (meth)acrylate or glycidyl (meth)acrylate; and
25 alicyclic (meth)acrylate such as cyclohexyl (meth)acrylate,
isobornyl (meth)a crylate, or dicyclopentenyl (meth)a crylate.
Incidentally, the monomers described above by way of
examplecanbeusedsinglyorincombinationoftwoormorekinds.
Further, the acrylic resinmaybeproducedbyusinga copolymer
bya compound, suchas styrene, cyclohexylmaleimide, orphenyl
maleimide, which is copolymerizable with these monomers.
5 In addition, for example, a resin with photosensitivity
may be produced by a reaction between a copolymer obtained by
copolymerizing carboxylic acidhaving anethylenic unsaturated
group such as (meth) acrylic acid, and a compound including an
epoxy group and an unsaturated double bond, such as glycidyl
10 methacrylate. For example, a resin with photosensitivity may
be produced by adding a carboxylic acid-containing compound,
such as (meth)acrylic acid, to a polymer of epoxy
group-containing (meth)acrylate, such as glycidyl
methacrylate, or a copolymer between this polymer and other
15 (meth) acrylate .
(Organic pigments)
As red pigments, for example, use can be made of C. I.
Pigment Red 7, 9, 14, 41, 48:1, 48:2, 48:3, 48:4, 81:1, 81:2,
81:3, 97, 122, 123, 146, 149, 168, 177, 178, 179, 180, 184, 185,
20 187, 192, 200, 202, 208, 210, 215, 216, 217, 220, 223, 224, 226,
227, 228, 240, 242, 246, 254, 255, 264, 272, and 279.
As yellow pigments, for example, use can be made of C. I.
Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17,
18, 20, 24, 31, 32, 34, 35, 35:1, 36, 36:1, 37, 37:1, 40, 42,
25 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 86, 93, 94,
95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115,
116, 117, 118, 119, 120, 123, 125, 126, 127, 128, 129, 137, 138,
139, 144, 146, 147, 148, 150, 151, 152, 153, 154, 155, 156, 161,
162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176,
177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 199, 213, and
214.
5 As blue pigments, for example, use can be made of C. I.
Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15:4, 15: 6, 16, 22, 60, 64,
and 80. Of these, C. I. Pigment Blue 15:6 is preferable.
As violet pigments, for example, use can be made of C. I.
Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, and 50.
10 Of these, C. I. Pigment Violet 23 is preferable.
As green pigments, for example, use can be made of C. I.
Pigment Green 1, 2, 4, 7, 8, 10, 13, 14, 15, 17, 18, 19, 26,
36, 45, 48, 50, 51, 54, 55, and 58. Of these, C. I. Pigment
Green 58, which is a halogenated zinc phthalocyanine green
15 pigment, is preferable.
(Color materials of black matrix BM)
A light-shielding color material included in the layer of
the black matrix BM is a color material which exhibits a
light-shield function by having absorption in a visible light
20 wavelength range. In the embodiment, as the light-shielding
color materials, for example, organic pigments, inorganic
pigments, and dyes are usable. As the inorganic pigments, for
example, carbon black and titanium oxide can be used. As the
dyes, for example, an azoic dye, anthraquinone dye,
25 phthalocyanine dye, quinonimine dye, quinoline dye, nitro dye,
carbonyl dye, and methine dye are usable. As regards the
organic pigments, the above-described organic pigments can be
adopted. Incidentally, a light-shielding component maybe one
kind, or a combination of two or more kinds with a proper ratio.
In addition, a volume resistance may be increased by resin
coatingonthe surfaceofthesecolormaterials, or, conversely,
5 the volume resistance may be decreased by imparting a slight
electrical conductivity by increasing the content ratio of the
color material to the base material of the resin. However,
since the volume resistancevalue of such light-shieldmaterial
is in a range of about 1 x lo8 - 1 x lo1' Qmcm, this is not such
10 a level as to affect the resistance value of the transparent
conductive film. Similarly, the specific dielectric constant
of the light-shield layer can be adjusted in a range of about
3 to 30 by the selectionor content ratio of the color material.
The specific dielectric constants of the coating film of the
15 black matrix BM, the coating film of the color pixel and the
transparent resin layer can be adjusted within the
above-described range of the specific dielectric constant, in
accordance with the design conditions and liquid crystal
driving conditions of the liquid crystal display device 1, 30.
20 In the present embodiment, there is no need to form a large
light -shield part in a case of using a silicon-based thin- f ilm
transistor, such as an amorphous silicon-based thin-film
transistor. It is possible to eliminate moir6 due to
non-uniformity of a black matrix pattern within a pixel at a
25 time of using a silicon-based thin-film transistor, and due to
The above-described embodiments may be variously altered
and appliedwithout departing fromthe spirit of the invention.
The above embodiments may be freely combined and used.
CLAIMS AMENDED UNDER ARTICLE 19
- 59 -
W E C L A I M :
1. A liquid crystal display device comprising:
an array substrate including a plurality of pixel
electrodes corresponding to a plurality of pixels arranged in
5 a matrix, and a black matrix which partitions the pixels;
a color filter substrate opposed to the array substrate
and including color filters corresponding to the plurality of
pixels;
a 1-iquid crystal layer provided between the array
10 substrate and the color filter substrate and having a negative
dielectric constant anisotropy;
a backlight unit provided on a back surface side of the
array substrate, the back surface side being opposite to a
liquid crystal layer side of the array substrate; and
15 a controller configured to control an application timing
of a liquid crystal driving voltage to the pixel electrodes,
and a light emission timing of the backlight unit,
wherein the backlight unit is an edge-lit-type unit
including a solid-state light-emission element array,
2 0 thepluralityofpixels include apicture element composed
of two red pixels, two green pixels and two blue pixels,
thepluralityofpixels are configuredtoeachhave a shape
which is elongated in a lateral direction, and configured such
that identical colors are arranged in the lateral direction,
2 5 and different colors are arranged in a vertical direction,
pixels neighboring in the lateral direction of the
plurality of pixels have shapes of line-symmetry with respect
t o a c e n t e r l i n e of t h e neighboring p i x e l s ,
t h e c o n t r o l l e r is c o n f i g u r e d t o e x e c u t e , based on a video
s i g n a l , s y n c h r o n i z a t i o n c o n t r o l between t h e a p p l i c a t i o n timing
of t h e l i q u i d c r y s t a l d r i v i n g v o l t a g e t o t h e p i x e l e l e c t r o d e s ,
5 and t h e l i g h t emission timing of t h e b a c k l i g h t u n i t , and
l i q u i d c r y s t a l m o l e c u l e s o f t h e neighboring p i x e l s tilt
i n d i r e c t i o n s of t h e line-symmetry with r e s p e c t t o t h e c e n t e r
l i n e when t h e l i q u i d c r y s t a l d r i v i n g v o l t a g e is a p p l i e d t o t h e
p i x e l e l e c t r o d e s corresponding t o t h e neighboring p i x e l s .
10 2 . The l i q u i d c r y s t a l d i s p l a y device of C l a i m l , wherein
t h e b l a c k m a t r i x is formed between p i x e l s neighboring i n t h e
v e r t i c a l d i r e c t i o n and is n o t f o r m e d b e t w e e n p i x e l s neighboring
i n t h e l a t e r a l d i r e c t i o n .
3 . The l i q u i d c r y s t a l d i s p l a y device o f C l a i m 1 , f u r t h e r
1 5 comprising a p l u r a l i t y of a c t i v e elements which a r e
electricallyconnectedtothepluralityofpixelelectrodes and
a r e formed o f a n oxide semiconductor using a composite metal
oxide a s a t r a n s p a r e n t channel m a t e r i a l .
4. The l i q u i d c r y s t a l d i s p l a y device of C l a i m l , wherein
2 0 t h e p l u r a l i t y o f p i x e l s a r e p a r a l l e l o g r a m m a t i c with a long s i d e
having an a n g l e y t o t h e l a t e r a l d i r e c t i o n , and a s h o r t s i d e
p a r a l l e l t o t h e v e r t i c a l d i r e c t i o n .
5. The l i q u i d c r y s t a l d i s p l a y device o f C l a i m 4 , wherein
two p i x e l s n e i g h b o r i n g i n t h e l a t e r a l d i r e c t i o n a r e of t h e same
2 5 c o l o r and have a V shape o r an i n v e r t e d - V s h a p e , and
a p a t t e r n o f t h e v s h a p e o r t h e i n v e r t e d - V s h a p e i s r e p e a t e d
i n t h e l a t e r a l d i r e c t i o n .
6. The liquid crystal display device ofClaim1, wherein
the plurality of pixels are rectangular with a long side in the
lateral direction, and a short side in the vertical direction.
7. The liquidcrystal display device of Claiml, wherein
5 the plurality of pixels include flaw lines para.Lle1 to the long
side of the pixel, and have shapes of the line-symmetry with
respect to the center line of the neighboring pixels.
8. The liquidcrystal display device ofClaim1, wherein
the plurality of pixels include slits parallel to the long side
10 of the pixel, and have shapes of the line-symmetry with respect
to the center line of the neighboring pixels.
9. The liquid crystal display device ofClaim1, wherein
the array substrate includes a plurality of common electrodes,
an insulation layer and the pixel electrodes on a transparent
15 substrate,
the common electrodepartlyoverlaps, whenviewed in plan,
the pixel electrode in the same pixel, and
the common electrodes included in the pixels neighboring
in the lateral direction are line-symmetric with respect to the
2 0 center line ofthe pixels neighboringin the lateral direction.
10. The liquid crystal display device of Claiml, further
comprising an optical control element disposed between the
array substrate and the backlight unit and including an array
of a plurality of triangular prisms and an array of a plurality
25 of semicylindrical lenses,
wherein a longitudinal direction of the plurality of
triangular prisms andalongitudinaldirection ofthe plurality
of semicylindrical lenses are nonparallel and have a
predetermined angle.
11. The liquidcrystal display device ofClaim1, further
comprising an optical control element disposed between the
5 array substrate and the backlight unit and including an array
of a plurality of triangular prisms and an array of a plurality
of semicylindrical lenses,
wherein a longitudinal direction of the plurality of
triangular prisms is substantially parallel to a longitudinal
10 direction of the plurality of semicylindrical lenses, and
a width of the triangular prism is double a length of the
pixel in the lateral direction.
12. The liquid crystal display device oi Claim 11,
wherein a width ofthe semicylindrical lens is an integer number
15 of times of a width of two pixels in the lateral direction.
13. The liquidcrystal display device ofClaim1, further
comprising an optical control element including an array of a
pluralityofsemicylindricallensesbetweenthearraysubstrate
and the backlight unit or on a surface side of the color filter
20 substratefthe surface sidebeinglocatedoppositetotheliquid
crystal layer side,
wherein a longitudinal direction of the plurality of
semicylindrical lenses is perpendicular to the lateral
direction.
14. T h e l i q u i d c r y s t a l d i s p l a y d e v i c e o f C l a i m 1 , wherein
the liquid crystal layer includes liquid crystal molecules of
vertical alignment.
15. T h e l i q u i d c r y s t a l d i s p l a y d e v i c e o f C l a i m 1 , f u r t h e r
comprising a l i g h t r e c e p t i o n e l e m e n t c o n f i g u r e d t o d e t e c t l i g h t
which is i n c i d e n t from an o b s e r v e r s i d e ,
wherein t h e c o n t r o l l e r j-s c o n f i g u r e d t o a d j u s t a n e m i s s i o n
5 angle of l i g h t by t h e b a c k l i g h t u n i t , based on d a t a measured
by t h e l i g h t r e c e p t i o n element.