SUBSTRATE FOR LIQUID CRYSTAL DISPLAY DEVICE,
AND LIQUID CRYSTAL DISPLAY DEVICE
Technical Field
The present invention relates to a substrate for a
liquid crystal display device, and a liquid crystal
10 display device using the substrate. The invention
relates particularly to a color filter substrate for a
vertically aligned liquid crystal display device, and a
vertically aligned liquid crystal display device using
the color filter substrate.
15 Background Art
In recent years, it has been desired to make an
image quality of a thin type display device such as a
liquid crystal display higher, decrease a cost thereof,
and save electric power therefor. A color filter for
20 the liquid crystal display device is required to have a
sufficient color purity, a high contrast, flatness, and
other properties to match with a higher image-quality
display.
For high image-quality liquid crystal displays,
25 various liquid crystal aligning modes or liquid crystal
driving modes such as VA (vertically alignment), HAN
(hybrid-aligned nematic), TN (twisted nematic), OCB
(optically compensated bend), CPA (continuous pinwheel
alignment), and the like, are suggested. As a result,
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a wide-viewing-angle and high-speed-response display
has been put into practical use.
For a liquid crystal display device in the VA
mode, which has a structure in which liquid crystals
are aligned vertically with a plane of a substrate,
such as a glass piece, to give a wide viewing angle and
easily operate in a high-speed response, in the HAN
mode, which is effective for giving a wide viewing
angle, or in other mode, higher-level of flatness for a
color filter (evenness of the film thickness thereof,
and a decrease in irregularities in the surface of the
color filter) and an electrical property, such as a
dielectric constant, are desired. Such the high imagequality
liquid crystal display pursues, as a main
theme, a technique of making a liquid crystal cell
thickness (liquid crystal layer thickness) thereof
smaller to decrease coloration when the devices are
viewed from an oblique direction. For the VA mode,
developments of various improved modes have been
advanced, and examples of the modes include MVA (multidomain
vertically alignment), PVA (patterned vertically
alignment), VAECB (vertically alignment electrically
controlled birefringence), VAHAN (vertical alignment
hybrid-aligned nematic), and VATN (vertically alignment
twisted nematic). A liquid crystal display device in a
vertical electric field mode, such as the VA mode, in
which a driving voltage is applied along the liquid
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crystal thickness direction, pursues, as main themes, a
higher-speed liquid crystal response, a wide viewing
angle technique, and a higher transmittance. About the
MVA technique, in order to overcome a problem in that
at the time of a liquid-crystal-driving-voltage
applying, vertically aligned liquid crystals are
unstable (that about liquid crystals initially having
vertical alignment to a surface of a substrate, the
direction in which the liquid crystals are inclined
(brought down) at the time of the voltage applying is
not easily settled), disclosed is a technique of
creating plural slit-form convex part, forming liquid
crystal domains between these slits, and further
forming domains having plural aligned directions,
thereby ensuring a wide viewing angle. Patent
Literature 1 discloses a technique for forming liquid
crystal domains using first and second alignment
regulating structures (slits).
Patent Literature 2 discloses a technique for
forming four liquid crystal domains using light
alignment. This patent literature discloses that the
following are necessary to ensure a wide viewing angle:
conducting alignment treatment plural times, which is
related to a strict control of a tilt angle (into
89 degrees); and alignment axes different in angle from
each other by 90°, in each domain.
Patent Literatures 3 and 4 each disclose a
4
technique for controlling vertically aligned liquid
crystals by effect of an oblique electric field using a
transparent electroconductive film (a transparent
electrode, a display electrode or a third electrode) of
5 a color filter substrate side, and first and second
electrodes of the array substrate side. According to
Patent Literature 3, liquid crystals having negative
dielectric constant anisotropy are used. According to
Patent Literature 4, liquid crystals having positive
10 dielectric constant anisotropy are described. Patent
Literature 4 never describes any liquid crystal having
the negative dielectric constant anisotropy.
Usually, a liquid crystal display device in the VA
mode, the TN mode, or other mode has a basic structure
15 in which liquid crystals are sandwiched between a color
filter substrate having a common electrode, and pixel
electrodes (for example, a transparent electrode formed
into a comb-teeth-form pattern and connected
electrically to TFT elements) for driving the liquid
20 crystals and an array substrate. In this structure, a
driving voltage is applied between the common electrode
on the color filter and the pixel electrodes formed in
the array substrate side to drive the liquid crystals.
A transparent electroconductive film as the pixel
25 electrodes or the common electrode on a surface of the
color filter is usually a thin film of an
electroconductive metal oxide, such as ITO (indium tin
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oxide), IZO (indium zinc oxide), or IGZO (indium
gallium zinc oxide).
As a technique disclosing a color filter, for
example, blue pixels, green pixels, red pixels or a
black matrix, Patent Literature 5 discloses, for
example, a technique of forming a transparent
electroconductive film above the black matrix and the
color pixels, and further laminating an overcoat layer
thereon. Patent Literature 6 discloses a technique of
forming a cross section of the black matrix into a
trapezoidal from. Patent Literature 3 described above
describes (in, for example, FIGS. 7 and 9 thereof) a
technique of forming a color filter onto a transparent
electrode (transparent electroconductive film), which
is a technique using plural stripe electrodes and
positive dielectric constant anisotropy. Additionally,
Patent Literature 7 discloses a technique of forming a
color filter onto a transparent electroconductive film.
Citation List
Patent Literature
Patent Literature 1: Japanese Patent No. 3957430
Patent Literature 2: Jpn. Pat. Appln. KOKAI
Publication No. 2008-181139
Patent Literature 3: Japanese Patent No. 2859093
25 Patent Literature 4: Japanese Patent No. 4364332
Patent Literature 5: Jpn. Pat. Appln. KOKAI
Publication No. 10-39128
6
Patent Literature 6: Japanese Patent No. 3228139
Patent Literature 7: Jpn. Pat. Appln. KOKAI
Publication No. 5-26161
Summary of Invention
5 Technical Problems
As described above, in the vertically aligned
liquid crystal display device, liquid crystal domains
are formed by use of alignment regulating structures
called slits to ensure the wide viewing angle (MVA
10 technique). When the liquid crystals have the negative
dielectric constant anisotropy, specifically, the
driving voltage is applied to the liquid crystals at a
position between two slits made of resin, and the
liquid crystals are formed above such as the color
15 filter, the liquid crystals are inclined into a
direction perpendicular to the slits as the display
device is viewed in plan. Thus, the liquid crystals
are aligned horizontally to the substrate plane.
However, the liquid crystals at the center of the space
20 between the two slits are not settled into a single
direction notwithstanding the voltage applying, so that
the liquid crystals are turned into spray alignment or
bend alignment. Such an alignment turbulence of the
liquid crystals gives roughness or unevenness to a
25 liquid crystal display. Moreover, in the MVA mode,
such a quantitative level that the liquid crystals are
inclined is hard to be minutely controlled by the
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driving voltage so as to cause a problem of half-tone
display, in addition to the above-mentioned problem.
The linearity between the driving voltage and a display
(i.e., response time) is particularly low, therefore,
5 there is a problem of a half-tone display based on a
low driving voltage.
To solve such problems, it is very effective to
use a manner using first, second and third electrodes
so that the alignment of the liquid crystals is
10 controlled by effect of the oblique electric field, as
described in Patent Literatures 3 and 4. The oblique
electric field makes it possible to set the direction
in which the liquid crystals are inclined. Moreover,
the oblique electric field makes it easy to control the
15 quantitative level that the liquid crystals are
inclined to produce a large advantageous effect for the
half-tone display.
However, even these techniques are insufficient as
countermeasures against a disclination of the liquid
20 crystals. The disclination is a problem in that, in a
pixel (the pixel is a minimum unit for display based on
liquid crystals and is identical in meaning to a
rectangular pixel described in the invention), regions
having different light transmittances are generated by
25 an unintended alignment turbulence of the liquid
crystals or non-alignment thereof.
According to Patent Literature 3, in order to fix
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a disclination at a center of each pixel, an alignment
control window having no transparent electroconductive
film at a pixel-center part (portion) of a counter
electrode (third electrode) is provided. However, the
5 literature does not disclose any method for overcoming
a disclination in the periphery of the pixel.
Moreover, the literature does not disclose any method
for minimizing the disclination although the
disclination at the pixel center can be fixed.
10 Furthermore, the literature does not describe a
technique for improving a response of the liquid
crystals.
Patent Literature 2 discloses that it is necessary
to control the tilt angle of the liquid crystals
15 strictly into 89 degrees and conduct alignment
treatment four times in order to ensure a wide viewing
angle.
According to Patent Literature 4, a dielectric
layer is laminated above the transparent
20 electroconductive film (transparent electrode), and the
oblique electric field is favorably increased
accordingly. However, as illustrated in FIG. 7 in
Patent Literature 4, vertically aligned liquid crystals
remain at the center of each pixel and an edge part of
25 the pixel after the voltage is applied thereto, causing
a problem in that the pixel is decreased in
transmittance or an aperture rate. When liquid
9
crystals having positive dielectric constant anisotropy
are used (Patent Literature 4 discloses, in the
description and Examples thereof, no liquid crystal
having negative dielectric constant anisotropy), the
5 pixel is not easily improved in transmittance because
of the disclination at the pixel center. Thus, this
technique is unlikely to be adopted for a transflective
type liquid crystal display device.
In the above-mentioned situation, an object of the
10 invention is to provide a substrate for a liquid
crystal display device that decreases a disclination,
is bright and has good response, and is optimal for
driving liquid crystals by an oblique electric field,
and a liquid crystal display device including the
15 substrate.
Solution to the Problems
A first aspect of the present invention provides a
substrate for a liquid crystal display device including
a black matrix, a transparent electroconductive film
20 and a resin layer that are each formed above a
transparent substrate. The black matrix is a lightshielding
layer in which light-shielding pigments are
dispersed in a resin, and includes openings. The resin
layer is formed above the transparent substrate
25 including the black matrix and the transparent
electroconductive film, forms a convex part above the
black matrix, and forms, in a region that passes
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through a center of each of the openings in the black
matrix, a concave part.
A second aspect of the present invention provides
a substrate for a liquid crystal display device
5 including: a transparent substrate; a black matrix
which is formed above the transparent substrate, is a
light-shielding layer in which light-shielding pigments
are dispersed in a resin, and has openings; a
transparent electroconductive film which is formed
10 above the transparent substrate including the black
matrix; and color pixels having colors which are formed
in each of pixel regions divided by the openings, and
are formed above the transparent electroconductive
film.
15 A third aspect of the present invention provides a
liquid crystal display device.including: the liquid
crystal display device substrate according to the first
or the second aspect; an array substrate which is
arranged opposite to the liquid crystal display device
20 substrate, and including liquid-crystal-driving
elements arranged in a matrix form thereon; and liquid
crystals which are held between the liquid crystal
display device substrate and the array substrate.
A fourth aspect of the present invention provides
25 a liquid crystal display device including: a color
filter substrate and an array substrate. The color
filter substrate and the array substrate are opposed
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and stuck to each other via liquid crystals. The color
filter substrate includes a black matrix having
rectangular openings, a transparent electroconductive
film, color pixels, and a resin layer above a
5 transparent substrate. The array substrate includes
elements driving the liquid crystals and being arranged
in a matrix form. The resin layer is arranged directly
or indirectly above the transparent electroconductive
film. A convex part protruded from a surface of the
10 resin layer is formed. A convex part is formed in a
region that passes through a center of each of the
rectangular openings in the black matrix. The array
substrate includes a comb-teeth-form first electrode
and a comb-teeth-form second electrode each of which
15 includes electroconductive metal-oxides which are
transparent in a range of visible wavelengths. The
second electrode is arranged below the first electrode
via an insulating layer between the first and second
electrodes. The second electrode is protruded from an
20 end of the first electrode into a direction along which
the liquid crystals are inclined.
Advantageous Effects of Invention
According to the invention, a substrate for a
liquid crystal display device that decreases a
25 disclination, is bright and has good responses, and is
optimal for driving liquid crystals by an oblique
electric field, and a liquid crystal display device
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including the substrate, are provided.
Brief Description of Drawings
FIG. 1 is a schematic sectional view of a
vertically aligned liquid crystal display device
according to an embodiment of the invention;
FIG. 2 is a view illustrating, on an enlarged
scale, a 1/2 region of a green pixel 14 of the
vertically aligned liquid crystal display device
illustrated in FIG. 1;
FIG. 3 is a view describing motions of liquid
crystals starting to be inclined in the vertically
aligned liquid crystal display device illustrated in
FIG. 1 just after a driving voltage is applied thereto;
FIG. 4 is a view illustrating a state that liquid
crystal molecules in the vertically aligned liquid
crystal display device illustrated in FIG. 1 are
aligned at the time of white display after the driving
voltage is applied thereto;
FIG. 5 is a view illustrating an alignment state
of the liquid crystal molecules of liquid crystals
aligned horizontally in a state that no voltage is
applied to a third, first and second electrodes;
FIG. 6 is a schematic sectional view describing
motions of the liquid crystals starting to be inclined
just after the driving voltage is applied thereto;
FIG. 7 is a view illustrating an alignment state
that the liquid crystal molecules are aligned
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approximate perpendicularly to a plane of a substrate
at the time of white display after the driving voltage
is applied thereto;
FIG. 8 is a view illustrating liquid crystal
molecules aligned vertically near the first electrode
when the first and second electrodes of the vertically
aligned liquid crystal display device illustrated in
FIG. 1 are each made into a comb-teeth-form pattern;
FIG. 9 is a view illustrating motions of liquid
crystal molecules in the vertically aligned liquid
crystal display device illustrated in FIG. 5, and
electric lines of force just after a liquid-crystaldriving
voltage is applied thereto;
FIG. 10 is a schematic sectional view of a
vertically aligned liquid crystal display device
according to a second embodiment of the invention;
FIG. 11 is a sectional view illustrating, on an
enlarged scale, a 1/2 region of a green pixel 14 in
FIG. 10, which is a rectangular pixel when viewed in
plan;
FIG. 12 is a view demonstrating motions of liquid
crystals starting to be inclined in the liquid crystal
display device illustrated in FIG. 10 just after a
driving voltage is applied thereto;
FIG. 13 is a view illustrating a state that the
liquid crystal molecules in the liquid crystal display
device illustrated in FIG. 10 are aligned at the time
14
of white display after the driving voltage is applied
thereto;
FIG. 14 is a view illustrating motions of the
liquid crystal molecules at the array substrate side of
5 the liquid crystal display device illustrated in
FIG. 10 by effect of drive-voltage applying;
FIG. 15 is a view illustrating motions of the
liquid crystal molecules at the array substrate side of
the liquid crystal display device illustrated in
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FIG. 10 by effect of the driving-voltage applying;
FIG. 16 is a partial sectional view illustrating a
substrate according to Example 1;
FIG. 17 is a partial sectional view illustrating a
substrate according to Example 2;
FIG. 18 is a partial sectional view illustrating a
substrate according to Example 3;
FIG. 19 is a partial sectional view illustrating a
substrate according to Example 4 ;
FIG. 20 is a partial sectional view illustrating a
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20 color filter substrate according to Example 5;
FIG. 21 is a partial sectional view illustrating a
color filter substrate according to Example 6;
FIG. 22 is a sectional view illustrating a liquid
crystal display device according to Example 7;
FIG. 23 is a sectional view illustrating a
transflective type liquid crystal display device
according to Example 8;
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FIG. 24 is a sectional view illustrating a color
filter substrate according to Example 9;
FIG. 25 is a sectional view illustrating a color
filter substrate according to Example 10;
FIG. 26 is a sectional view illustrating a color
filter substrate according to Example 11;
FIG. 27 is a sectional view illustrating a color
filter substrate according to Example 12;
FIG. 28 is a sectional view illustrating a color
10 filter substrate according to Example 13;
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FIG. 29 is a sectional view illustrating a liquid
crystal display device according to Example 14;
FIG. 30 is a sectional view illustrating a liquid
crystal display device according to Example 15;
FIG. 31 is a sectional view illustrating a liquid
crystal display device according to Example 16; and
FIG. 32 is a sectional view illustrating a liquid
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crystal display device according to Example 17.
Description of Embodiments
Hereinafter, embodiments of the present invention
will be described.
A first embodiment of the invention has a
prerequisite condition of using a liquid crystal
display device including a first substrate with a resin
25 layer formed above its surface and a color filter or no
color filter and a second substrate above which a
liquid crystal driving element such as a TFT is formed,
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and then opposing and laminating (bonding) the
substrates to sandwich a liquid crystal layer
therebetween. The first embodiment of the invention
additionally utilizes a technique of making use of an
oblique electric field generated by an electrode
structure having the following: a transparent
electroconductive film as a third electrode arranged to
the first substrate; a first electrode as a pixel
electrode; and a second electrode having a different
potential from the first electrode.
Furthermore, the inventors have found out that: a
resin layer is arranged over the first substrate to
cover a black matrix; a convex part (region) protruded
from the front surface of the resin layer is made above
the black matrix; a concave part is made in a region
that passes through a center of each opening in the
black matrix; and these can be used for controlling
alignment of the liquid crystals. The inventors have
provided a new technique obtained by combining this
finding with a structure of the third electrode
(transparent electroconductive film). The convex part
is an overlap part made of the black matrix and the
resin layer, and the alignment of liquid crystals at an
inclined part of this convex part is used to incline
the liquid crystals when a driving voltage is applied.
Similarly, at the concave part also, the liquid
crystal alignment at a shoulder part of the resin layer
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is used to incline the liquid crystals. Motions of the
liquid crystals will be detailed in Examples that will
be given later. The height of the convex part ranges
preferably from 0.5 to 2 ~m. If the height is 0.4 ~m
5 or less, an advantageous effect of "a trigger for
inclining the liquid crystals" is insufficient at a
time of voltage applying. If the height is more than
2 ~m, an inconvenience may be caused to the flow of the
liquid crystals when cells of the liquid crystals are
10 produced.
The inclined part of the black matrix may have a
round shape, and a sectional shape of the black matrix
is, for example, a semilunar, trapezoidal, triangular
shape in a display region. A inclination angle of the
15 black matrix from a substrate plane is not particularly
specified as far as the height of the convex part is
more than 0.5 ~m. When an aperture rate (transmittance
of the rectangular pixels) is allowable, the angle may
be a low inclination angle such as 20 or 30, and needs
20 only not to give a reverse-tapered form (the form of an
upside-down trapezoid, the upper side of which is
longer than the bottom side). However, the inclination
angle is preferably from 30 to 800 to restrict the
aperture rate effectively.
25 A second embodiment of the invention is applied to
liquid crystals having initial alignment that are
vertical alignment, and has a prerequisite condition of
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using a liquid crystal display device including a color
filter substrate and an array substrate above which a
liquid crystal driving element such as a TFT is formed,
and then opposing and laminating the substrates to
sandwich a liquid crystal layer for vertical alignment
therebetween. The second embodiment of the invention
additionally utilizes a technique of making use of an
oblique electric field generated by an electrode
structure having the following: a transparent
electroconductive film as a third electrode arranged to
the color filter substrate to cover a black matrix; a
first electrode as a pixel electrode; and a second
electrode having a different potential from the first
electrode.
Furthermore, the inventors have found out that: a
convex part protruded from a front surface of the color
pixels is made above the black matrix; a concave part
is made in a region that passes through a center of
each of the color pixels; and these can be used for
controlling alignment of the liquid crystals. The
inventors have provided a new technique obtained by
combining this finding with a structure of the third
electrode (transparent electroconductive film). The
convex part is an overlap part (region) made of
different-two-color pixels out of the color pixels, and
the alignment of the liquid crystals at an inclined
part of this convex part is used to bring the liquid
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crystals down when a driving voltage is applied.
Technical terms in the present specification are
briefly described herein.
A black matrix is a light-shielding pattern around
pixels each of which is a minimum unit for display, or
along both sides of the pixel in order to increase a
contrast for liquid crystal display. Its lightshielding
layer is a coating film in which lightshielding
pigments are dispersed in a transparent
resin, and is generally a light-shielding coating film
having photosensitivity and generated by performing
pattern-formation in a photolithographic manner
including light exposure and development.
Rectangular pixels denote respective openings in
the black matrix, and each have the same meaning as the
above-mentioned pixel. A color layer is a coating film
in which organic pigments that will be described later
are dispersed in a transparent resin. Members obtained
by forming the color layer onto rectangular pixels in a
photolithographic manner to have a pattern are called
color pixels.
The liquid crystals applicable to the first
embodiment are liquid crystals having vertical
alignment or parallel alignment as initial alignment
(when no driving voltage is applied thereto). The
liquid crystals applicable to the second embodiment are
liquid crystals having vertical alignment as initial
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alignment (when no driving voltage is applied thereto) .
The dielectric constant anisotropy of the liquid
crystals may be positive or negative. When the liquid
crystals having negative dielectric constant anisotropy
are applied to the present embodiments, an alignment
treatment of an alignment film for setting the tilt
angle can be omitted. In other words, the alignment
film used in each of the first and second embodiments
needs only to be subjected to heat treatment after the
film is formed by printing. Thus, rubbing treatment,
optical alignment or other alignment treatment can be
omitted. In the first and second embodiments, the
transmittance of the center of their rectangular pixels
can be raised to make it possible to supply a color
filter substrate in which importance is placed on
brightness rather than color purity, for example, a
color filter substrate suitable for a transflective
type liquid crystal display device.
The materials of the first and second electrodes
on the array substrate side of the liquid crystal
display device according to each of the first and
second embodiments may be a thin film of
electroconductive metal-oxides such as ITO.
Alternatively, a metal thin film higher in
electroconductivity than the metal-oxide thin film may
be used. In the case of a reflection type or a
transflective type liquid crystal display device, a
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thin film of aluminum or an aluminum alloy may be used
for either the first or second electrode.
In the first and second embodiments, the
dielectric constant of each of their color layers,
which is relatively an impotent property, is determined
substantially unequivocal in accordance with the
proportion of organic pigments added as a colorant to
the transparent resin; thus, the dielectric constant
cannot be easily adjusted within a large range. In
other words, the kind or the content by percentage of
the organic pigments in the color layer is set in
accordance with a color purity necessary for the liquid
crystal display device. By the kind or content, the
dielectric constant of the color layer is substantially
determined. When the proportion of the organic
pigments is made high and the color layer is made thin,
the dielectric constant can be adjusted to 4 or more.
When a high-refractive-index material is used as the
transparent resin, the dielectric constant can slightly
be increased.
It may be optimize the respective thicknesses of
the color layer and the resin layer depending on a
relationship thereof with the cell gap (liquid crystal
layer thickness) of the liquid crystals to be used.
For example, when the thicknesses of the color layer
and the resin layer become small from the viewpoint of
required electrical properties, the thickness of the
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liquid crystal layer can be made large. When the film
thicknesses of the formers are large, the thickness of
the liquid crystal layer can be made small,
corresponding to the large thicknesses.
The first and second electrodes are electrically
insulated from each other in the thickness direction by
an insulating layer, as will be described later. The
thicknesses of the color layer, the resin layer and the
insulating layer may be adjusted in accordance with the
thickness of the liquid crystal layer, the dielectric
constants thereof, applied voltage, and driving
conditions. When the insulating layer is formed to be
made of SiNx (silicon nitride), a practical film
thickness of this insulating layer ranges from 0.1 to
0.5 pm. The positions of the first and second
electrodes in the film thickness may be positions
reverse thereto. In the liquid crystal display devices
according to the present embodiments, effective use can
be made of an oblique electric field; thus, the devices
can be increased in transmittance by extending a range
which electric lines of force reach at the time of the
driving-voltage applying into the direction of the
thickness of films including the liquid crystal layer
and the transparent resin layer.
Hereinafter, a description will be made about the
motion of a structure in which a transparent
electroconductive film is laminated above each of
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liquid crystal display device substrates according to
each of the present embodiments to cover a black
matrix; and the motion of an overlap part of a resin
layer or color layer above the black matrix, or of a
5 concave part passing the center of each pixel region.
FIG. 1 is a schematic sectional view of a
vertically aligned liquid crystal display device
according to the first embodiment of the invention.
This liquid crystal display device has a structure in
10 which a substrate 11 and an array substrate 21 are
stuck to each other in such a form that liquid crystals
17 are sandwiched therebetween. The substrate 11 is
formed by forming, onto a transparent substrate la, a
black matrix 2, a third electrode 3 which is a
15 transparent electroconductive film, and a resin layer
18 successively. In the array substrate 21, second
electrodes 4 and third electrodes 5 are formed above a
transparent substrate lb. Illustration of a protecting
layer, an alignment film, a polarizing plate, a
20 retardation film, and others are omitted.
FIG. 2 is a sectional view illustrating, on an
enlarged scale, a 1/2 region of an opening in FIG. 1,
this opening being a rectangular opening when viewed in
plan. The polarizing plate is in a crossed Nichol
25 form, and the liquid crystal display device is a normal
black liquid crystal display device. For example, the
polarizing plate may be a polarizing plate which is
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yielded by drawing a polyvinyl alcohol based organic
polymer containing iodine, and which has an absorption
axis in the drawn direction by the drawing. FIG. 2
illustrates respective alignment states of liquid
crystal molecules 17a, 17b, 17c and 17d in the
vertically aligned liquid crystals 17 in the state that
no voltage is applied to the third electrode 3, which
is the transparent electroconductive film formed to the
substrate 11, and the first electrodes 4 and the second
electrodes 5 formed to the array substrate 21.
The liquid crystals at the center of the
rectangular opening (1/2 pixel) is aligned vertically
to the plane of the pixel. However, the liquid crystal
molecule 17a, which is at a shoulder part lSa of a
concave part 23, and the liquid crystal molecules 17b
and 17c, which are at a shoulder part lSb of a convex
part 24, are slightly obliquely aligned. When a
liquid-crystal-driving voltage is applied in this
obliquely aligned state, the liquid crystal molecules
17a, 17b and 17c are inclined into the direction of
arrows A. The formation of the concave part 23 and the
convex part 24 causes the liquid crystal molecules 17a,
17b and 17c to be substantially tilted without
subjecting this liquid crystal device to rubbing or
other alignment treatment.
In the present embodiment, use may be made of both
of liquid crystals having negative dielectric constant
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anisotropy, and liquid crystals having positive
dielectric constant anisotropy. As the liquid crystals
having negative dielectric constant anisotropy, use may
be made of, for example, nematic liquid crystals having
a birefringence of about 0.1 at room temperature or
thereabout. About the liquid crystals having positive
dielectric constant anisotropy, the scope of species to
be selected is wide; thus, various liquid crystal
materials may be used. The thickness of the liquid
crystal layer does not need to be particularly limited.
The 6nd of a liquid crystal layer usable effectively in
the embodiment ranges from about 300 to 500 nm.
In examples of the invention which will be
detailed later, use may be made of a liquid crystal
material including, in the molecular structure thereof,
a fluorine atom (hereinafter referred to as a fluorinecontaining
liquid crystal) as the vertically aligned
liquid crystal material. When a liquid-crystal-driving
voltage is applied (to the electrodes), an intense
electric field is substantially generated at protruded
parts of the first and second electrodes; thus, the
liquid crystal driving can be attained by use of a
liquid crystal material lower in dielectric constant
(smaller in dielectric constant anisotropy) than liquid
crystal materials used in conventional vertical
alignment. In general, liquid crystal material small
in dielectric constant anisotropy is low in viscosity;
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26
thus, when substantially the same electric field
strength (as applied to liquid crystal material large
in the anisotropy) is applied (to the material small
therein), a higher-speed response is attained.
Moreover, because the fluorine-containing liquid
crystal is low in dielectric constant, the liquid
crystal takes in a small amount of ionic impurities.
Thus, the fluorine-containing liquid crystal is also
small in performance-deteriorations, such as a decline
of voltage retention rate, based on impurities so that
an uneven display is not easily generated. The
alignment film, the illustration of which is omitted,
may be, for example, can be hardened from a polyimide
based organic polymer film by heating. One to three
retardation films may be used in such a form that the
plate(s) is/are laminated with one or more of the
polarizing plates.
In the embodiment, when the liquid crystals have
negative dielectric constant anisotropy, the motions of
the vertical alignment liquid crystals are inclined
into a horizontal direction at the time of the drivingvoltage
applying. When the liquid crystals have
positive dielectric constant anisotropy, the motions of
the horizontal alignment liquid crystals are tilted up
to a vertical direction at the time of the drivingvoltage
applying.
FIG. 3 is a view demonstrating motions of the
5
10
15
20
25
27
liquid crystals which begin to be inclined just after
the driving-voltage applying. Specifically, with the
voltage applying, first, the liquid crystal molecules
17a, 17b and 17c begin to be inclined, and subsequently
liquid crystal molecules around these liquid crystal
molecules are inclined. In the concave part 23 and the
convex part 24, the transparent resin layer, which is a
dielectric body, is thin or absent; thus, the applied
driving voltage is easily transmitted to the liquid
crystal molecules unlike that of the pixel center, so
that the motions of the liquid crystal molecules in
these regions functions as a trigger for motions that
the liquid crystals are inclined. In an opposite-side
1/2 pixel of the pixel, the direction in which the
liquid crystals are inclined is a reverse direction,
which is not illustrated in FIG. 3. Accordingly,
optical compensation in a half-tone display can be
attained depending only on the value of the driving
voltage. As a result, a wide visual field angle can be
ensured even without forming four multi-domains as in
MVA liquid crystals. In a half-tone (for example, the
individual liquid crystal molecules are in the state of
being oblique), the liquid crystal alignment thereof is
liquid crystal alignment that the 1/2 pixel in FIG. 3
and the opposite-side 1/2 pixel have inclination
gradients reverse to each other, so that these
1/2 pixels, which are reverse to each other, attain a
5
10
15
20
25
28
visual-angle enlargement.
FIG. 4 is a view illustrating a state that the
liquid crystal molecules are aligned at the time of
white display after the driving-voltage applying. As
illustrated in FIG. 4, the liquid crystal molecules are
aligned in substantially parallel to the substrate
plane.
The following will describe the motions of liquid
crystal molecules in a liquid crystal display device in
which liquid crystals having positive dielectric
constant anisotropy are used.
FIG. 5 illustrates an alignment state of the
liquid crystal molecules 17a, 17b, 17c and 17d which
are the horizontally aligned liquid crystals in the
state that no voltage is applied to the third electrode
3, the first electrode 4, and the second electrode 5
which are transparent electroconductive films. The
liquid crystals at the center of the pixel (1/2 pixel)
is aligned vertically to the pixel plane; however,
liquid crystal molecules at respective shoulder parts
14b and 14a of the convex part 24 and the concave part
23 are slightly obliquely aligned. When a liquidcrystal-
driving voltage is applied to the electrodes in
this oblique aligned state, the liquid crystal
molecules 17a, 17b, and 17c are inclined into
respective directions of arrows as illustrated in
FIG. 6.
5
15
10
29
FIG. 6 is a schematic sectional view describing
the motions of the liquid crystals beginning to be
inclined just after the driving-voltage applying. With
the voltage applying, first, the liquid crystal
molecules 17a, 17b, and 17c begin to be raised up into
a vertical direction, and subsequently liquid crystal
molecules around these liquid crystal molecules are
raised up. In the convex part 24 and the concave part
23, the transparent resin layer, which is a dielectric
body, is thin or absent; thus, the applied driving
voltage is easily transmitted to the liquid crystal
molecules unlike that of the pixel center, so that the
motions of the liquid crystal molecules in these
regions functions as a trigger for motions that the
liquid crystals are inclined. In an opposite-side
1/2 pixel of the pixel, the direction in which the
liquid crystals are inclined is a reverse direction,
which is not illustrated in FIG. 6.
FIG. 7 illustrates a state that the liquid crystal
20 molecules are aligned at the time of white display
after the driving-voltage applying. The liquid crystal
molecules are aligned substantially vertically to the
substrate plane.
The above has described the behavior of the liquid
25 crystal molecules near the substrate 11 side. However,
in a liquid crystal display device according to a
different embodiment of the invention, at the array
30
substrate 21 side also, liquid crystal molecules can be
inclined in the same direction as at the abovementioned
substrate 11 side. Hereinafter, such an
example will be described about a case where liquid
5 crystals having negative dielectric constant anisotropy
are used.
In a liquid crystal display device illustrated in
FIG. 8, a first electrode includes comb-teeth-form
electrodes 4a, 4b, 4c and 4d. Similarly, a second
10 electrode includes comb-teeth-form electrodes Sa, 5b,
5c and 5d. Liquid crystal molecules 27a, 27b, 27c and
27d near the first electrode regions 4a, 4b, 4c and 4d
are vertically aligned.
In the liquid crystal display device in FIG. 8,
15 the second electrodes Sa, 5b, 5c and 5d are arranged in
such a manner that ends thereof are protruded from
respective ends of the first electrodes 4a, 4b, 4c and
4d in a direction from the pixel toward a black matrix
2, which is a direction in which the liquid crystal 27a
20 is inclined. Respective quantities 28 of the
protrusions can be adjusted into various values by a
liquid crystal material to be used, the driving
voltage, and the thickness of the liquid crystal cells
and other dimensions. The protrusion quantities 28 are
25 each sufficient even when the quantity 28 is a small
quantity of 1 to 5 pm. The width of each of regions
where the first electrode regions 4a, 4b, 4c and 4d
5
10
15
20
25
31
overlap the second electrode regions Sa, Sb, Sc and Sd,
respectively, is represented by reference number 29.
Illustration of any alignment film is omitted. The
respective widths of the overlapped "regions can be
appropriately adjusted.
FIG. 9 shows respective motions of the liquid
crystal molecules 27a, 27b, 27c and 27d together with
lines of electric force 30a, 30b, 30c and 30d just
after a liquid-crystal-driving voltage is applied to
the electrodes. The liquid crystal molecules 27a, 27b,
27c and 27d begin to be inclined into a direction A of
the lines of electric force by the voltage applying.
This direction in which the liquid crystal molecules
are inclined is identical with the direction in which
the liquid crystal molecules 17a, 17b and 17c
illustrated in FIG. 3 are inclined; therefore, liquid
crystal molecules in the illustrated pixel are
instantaneously inclined in the same direction, so that
the responses of the liquid crystals can be largely
improved.
In order to orient the direction in which the
liquid crystal molecules above protruded parts of the
second electrodes Sa, Sb, Sc and Sd from respective
ends of the first electrode regions 4a, 4b, 4c and 4d
are inclined easily, the following examples of manners
can be attained. Such examples include the manner of
tapering the ends of the first electrodes, that of
32
making the respective layer thicknesses of the first
electrodes large; and that of etching an insulating
layer below the first electrodes partially to make the
thickness of an insulating layer above the second
5 electrodes small. The liquid crystal molecules are
thus slightly tilted so that the molecules are easily
inclined even by effect of a low voltage.
FIG. 9 illustrates a 1/2 pixel of the pixel.
Desirably, the direction in which the second electrodes
10 are protruded in the other 1/2 pixel of the pixel is
centrosymmetrical or linearly symmetrical with the
1/2 pixel in FIG. 9, and is a reverse direction. The
pattern of each of the comb-teeth-form electrodes may
be in the form of V shapes, or are inclined when viewed
15 in plan. Alternatively, the comb-teeth-form patterns
may have the comb-teeth directions of which are varied
by 90° in the units of a 1/4 pixel. Such an electrode
patterns are desirably centrosymmetrical or linearly
symmetrical about the center of the pixel.
20 When the pixel is a longitudinal rectangular
pixel, it is preferred that the shape of a concave part
23 when viewed in plan is straight linear in a region
passing through the center of the pixel, so that the
line divides the rectangular pixel into two parts.
25 However, in accordance with the respective comb-teeth
pattern shapes of the first and second electrodes, the
shape may be such a shape that the part 23 is extended
5
10
15
20
25
33
into a cross form or X-shaped form from the center of
the rectangular pixel. When the concave part is made
into the cross form or X-shaped form, it is desired to
arrange the protruded parts of the second electrodes
into rectangular-pixel-four-side (or black-matrix)
directions from the first electrodes. The comb-teeth
pattern of the first electrodes and that of the second
electrodes are each desirably centrosymmetrical or
linearly symmetrical about the center of the
rectangular pixel. When the liquid crystals are driven
in the state that the pixel is divided, optical
compensation can be completely attained to make it
possible to obtain a vertically aligned liquid crystal
display device having a wide visual field angle and
giving no color change even when its display is viewed
from any angle.
A voltage for driving the liquid crystals is
applied to the first electrode. However, the second
electrode and the third electrode may be made into a
common potential. The overlapped part 29, where the
first electrode and second electrode is overlapped, as
illustrated in FIG. 8, may be used as an auxiliary
capacitor.
In (each of the examples of) the embodiment
illustrated in FIGS. 1 to 9, no color filter is formed
to the substrate 11. However, a color filter may be
formed to be the substrate to form a color filter
34
substrate. In this case, the color filter is formed
between the transparent electroconductive film 3 and
the resin layer 18. Color pixels constituting the
color filter are not limited to three color pixels of
5 red pixels, green pixels, and blue pixels. A
complementary color pixel, such as a yellow pixel,
and/or a white pixel (a transparent pixel) may be added
thereto.
FIG. 10 is a schematic sectional view of a
10 vertically aligned liquid crystal display device
according to the second embodiment of the invention.
This liquid crystal display device has a structure in
which a color filter substrate (hereinafter referred to
briefly as a color filter substrate) 11 and an array
15 substrate 21 are stuck to each other in such a form
that liquid crystals 17 is sandwiched therebetween.
The color filter substrate 11 is formed by forming,
onto a transparent substrate la, a black matrix 2, a
third electrode 3 which is a transparent
20 electroconductive film, each green pixel 14, each red
pixel 15, and each blue pixel 16 successively. In the
array substrate 21, second electrodes 4 and third
electrodes 5 are formed above a transparent substrate
lb. Illustration of one or more protecting layers,
25 alignment films, polarizing plates, and retardation
films, and others is omitted.
FIG. 11 is a sectional view illustrating, on an
35
enlarged scale, a 1/2 region of the green pixel 14 in
FIG. 10, this pixel being a rectangular pixel when
viewed in plan. The polarizing plate is in a crossed
Nichol form, and the liquid crystal display device is a
5 normally black. FIG. 11 illustrates respective
alignment states of liquid crystal molecules 17a, 17b,
17c and 17d in the liquid crystals 17 aligned
vertically in the state that no voltage is applied to
the third electrode 3, which is the transparent
10 electroconductive film formed to the color filter
substrate, and the first electrodes 4 and the second
electrodes 5 formed to the array substrate 21.
The liquid crystals at the center of the green
pixel 14 (1/2 pixel) are aligned vertically to the
15 plane of the green pixel. However, the liquid crystal
molecule 17a, which is at a shoulder part 14a of a
concave part 23, and the molecules 17b and 17c, which
are at a shoulder part 14b of a convex part 24, are
somewhat obliquely aligned. When a liquid-crystal-
20 driving voltage is applied to the electrodes in this
obliquely aligned state, the liquid crystal molecules
17a, 17b and 17c are inclined into the direction of
arrows A. The formation of the concave part 23 and the
convex part 24 causes the liquid crystal molecules 17a,
25 17b and 17c to be substantially tilted without
subjecting this liquid crystal device to an alignment
treatment such as rubbing.
36
The motions of the liquid crystal molecules by the
driving-voltage applying are illustrated in FIGS. 12
and 13. The motions are the same as illustrated in
FIGS. 3 and 4.
5 The above has described the behavior of the liquid
crystal molecules near the substrate 11 side. However,
at the array substrate 21 side thereof also, liquid
crystal molecules can be inclined in the same direction
as at the above-mentioned substrate 11 side. Such an
10 example is illustrated in FIGS. 14 and 15 about a case
where liquid crystals having negative dielectric
constant anisotropy are used. The motions of the
liquid crystal molecules in this case are the same as
in FIGS. 8 and 9.
15 When a TFT, which is an active element, is formed
to be made of, for example, an oxide semiconductor, the
aperture rate (numerical aperture) of its pixel can be
improved. A typical example of the oxide semiconductor
is a multi-oxide of indium, gallium and zinc, which is
20 called IGZO.
Hereinafter, examples will be given about a
transparent resin, organic pigments, and others that
are usable in the liquid crystal display substrate
according to the present embodiment.
25 (Transparent Resin)
A photosensitive coloring composition used in the
formation of the light-shielding layer, the color
37
layer, and the resin layer contains, besides a pigment
dispersed substance, a polyfunctional monomer,
photosensitive resin or non-photosensitive resin, a
polymerization initiator, a solvent and others.
5 Highly-transparent organic resins which are usable in
the embodiment, such as photosensitive resin and nonphotosensitive
resin, are collectively referred to as a
transparent resin.
Examples of the transparent resin include
10 thermoplastic resin, thermosetting resin, and
photosensitive resin. Examples of the thermoplastic
resin include butyral resin, styrene/maleic acid
copolymer, chlorinated polyethylene, chlorinated
polypropylene, polyvinyl chloride, vinyl chloride/vinyl
15 acetate copolymer, polyvinyl acetate, polyurethane
resin, polyester resin, acrylic resin, alkyd resin,
polystyrene resin, polyamide resin, rubbery resin,
cyclic rubbery resin, celluloses, polybutadiene,
polyethylene, polypropylene, polyimide resin, and the
20 like. Examples of the thermosetting resin include
epoxy resin, benzoguanamine resin, rosin-modified
maleic acid resin, rosin-modified fumaric acid resin,
melamine resin, urea resin, phenolic resins and the
like. The thermosetting resin may be a resin obtained
25 by causing melamine resin to react with a compound
containing isocyanate groups.
38
(Alkali-Soluble Resin)
In order to form light-shielding layer, light
scattering layer, color layer, transparent resin layer
and cell gap regulating layer usable in the present
5 embodiment, it is preferred to use a photosensitive
resin composition which can be made into a pattern in a
photolithographic manner. A resin therefor, which is
transparent, is desirably a resin to which alkalisolubility
is given. The alkali-soluble resin is not
10 particularly limited as far as the resin is a resin
containing a carboxyl group or a hydroxyl group.
Examples thereof include epoxy acrylate resin, Novolak
resin, polyvinyl phenol resin, acrylic resin, carboxylgroup-
containing epoxy resin, carboxyl-group-containing
15 urethane resin, and the like. Of these resins,
preferred are epoxy acrylate resin, Novolak resin, and
acrylic resin. Particularly preferred are epoxy
acrylate resin, or Novolak resin.
(Acrylic Resin)
20 Typical examples of the transparent resin
adoptable in the embodiment are acrylic resins
described below.
The acrylic resins are each a polymer yielded by
use of, for example, the following as a monomer:
25 (meth)acrylic acid; an alkyl (meth)acrylate such as
methyl (meth) acrylate, ethyl (meth) acrylate, propyl
(meth) acrylate, butyl (meth) acrylate, t-butyl
39
(meth)acrylate penzyl (meth) acrylate, lauryl
(meth) acrylate, or the like; a hydroxyl-groupcontaining
(meth)acrylate such as hydroxylethyl
(meth) acrylate, hydroxylpropyl (meth) acrylate, or the
5 like; an ether-group-containing (meth)acrylate such as
ethoxyethyl (meth) acrylate, glycidyl (meth) acrylate, or
the like; or an alicyclic (meth)acrylate such as
cyclohexyl (meth) acrylate, isobornyl (meth) acrylate,
dicyclopentenyl (meth) acrylate, or the like.
10 The above-mentioned monomers may be used alone or
in combination of two or more thereof. The transparent
resin may be a copolymer made from the monomer(s) and a
compound which can be copolymerized therewith, such as
styrene, cyclohexylmaleimide, or phenylmaleimide.
15 Moreover, a resin having photosensitivity can also
be yielded by copolymerizing a carboxylic acid having
an ethylenically unsaturated group, such as
(meth)acrylic acid, therewith, and then causing the
resultant copolymer to react with a compound having an
20 epoxy group and an unsaturated double bond, such as
glycidyl methacrylate, or by adding a carboxylic-acidcontaining
compound such as (meth)acrylic acid to a
polymer made from an epoxy-group-containing
(meth) acrylate, such as glycidyl methacrylate, or to a
25 copolymer made from this polymer and a different
(meth) acrylate.
Furthermore, a resin having photosensitivity can
40
also be yielded by causing a hydroxyl-group-containing
polymer made from a monomer such as hydroxyethyl
methacrylate to react with a compound having an
isocyanate group and an ethylenically unsaturated bond,
5 such as methacryloyloxyethyl isocyanate.
As described above, a carboxyl-group-containing
resin can be yielded by causing a copolymer made from
hydroxyethyl methacrylate having plural hydroxyl
groups, or other monomer, to react with a polybasic
10 acid anhydride to introduce carboxyl groups to the
copolymer. The method for producing the carboxylgroup-
containing resin is not limited to only this
method.
Examples of the acid anhydride used in this
15 reaction include maloic anhydride, succinic anhydride,
maleic anhydride, itaconic anhydride, phthalic
anhydride, tetrahydrophthalic anhydride,
hexahydrophthalic anhydride, methyltetrahydrophthalic
anhydride, and trimellitic anhydride.
20 The acid value of the solid content in each of the
above-mentioned acrylic resins is preferably from 20
to 180 mgKOH/g. If the acid value is less than
20 mgKOH/g, the photosensitive resin composition is too
small in development rate so that a time required for
25 the development thereof becomes long. As a result, the
substrate of the embodiment tends to be poor in
productivity. If the acid value in the solid content
5
10
15
20
25
41
is larger than 180 mgKOH/g, the composition is
reversely too large in development rate. Thus, an
inconvenience that after the development the pattern is
peeled or chipped tends to be caused.
When the above-mentioned acrylic resins each have
photosensitivity, the double bond equivalent of the
acrylic resin is preferably 100 or more, more
preferably from 100 to 2000, most preferably from 100
to 1000. If the double bond equivalent is more than
2000, the resin composition may not gain a sufficient
photo-curability.
(Photopolymerizable Monomer)
Examples of the photopolymerizable monomer include
various acrylates and methacrylates such as 2hydroxyethyl
(meth) acrylate, 2-hydroxypropyl
(meth) acrylate, cyclohexyl (meth) acrylate, polyethylene
glycol di(meth)acrylate, pentaerythritol
tri(meth)acrylate, trimethylolpropane
tri(meth)acrylate, dipentaerythritol
hexa (meth) acrylate, tricyclodecanyl (meth) acrylate,
melamine (meth) acrylate, epoxy(meth)acrylate or the
like, (meth)acrylic acid, styrene, vinyl acetate,
(meth)acrylamide, N-hydroxymethyl(meth)acrylamide,
acrylonitrile or the like.
It is also preferred to use a polyfunctional
urethane acrylate having a (meth)acryloyl group, which
is yielded by causing a polyfunctional isocyanate to
42
react with a (meth)acrylate having a hydroxyl group.
The combination of the (meth)acrylate having a hydroxyl
group with the polyfunctional isocyanate is any
combination, and is not particularly limited. About
5 the polyfunctional urethane isocyanate, a single
species thereof may be used alone, or two or more
species thereof may be used in combination.
(Photopolymerization Initiator)
Examples of the photopolymerization initiator
10 include acetophenone compounds such as 4phenoxydichloroacetophenone,
4-t-butyldichloroacetophenone,
diethoxyacetophenone, 1-(4isopropylphenyl)-
2-hydroxy-2-methylpropane-l-one,
I-hydroxycyclohexyl phenyl ketone, and 2-benzyl-2-
15 dimethylamino-l-(4-morpholinophenyl)-butane-l-one;
benzoin compounds such as benzoin, benzoin methyl
ether, benzoin ethyl ether, benzoin isopropyl ether,
and benzyl dimethyl ketal; benzophenone compounds such
as benzophenone, benzoylbenzoic acid, methyl
20 benzoylbenzoate, 4-phenylbenzophenone,
hydroxybenzophenone, acrylated benzophenone, 4-benzoyl4'-
methyldiphenylsulfide; thioxanthone compounds such
as thioxanthone, 2-chlorothioxanthone, 2methylthioxanthone,
isopropylthioxanthone, and 2,4-
25 diisopropylthioxanthone; triazine compounds
such as 2,4,6-trichloro-s-triazine, 2-phenyl4,6-
bis(trichloromethyl)-s-triazine,
5
10
15
20
25
43
2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-striazine,
2-(p-tolyl)-4,6-bis(trichloromethyl)-striazine,
2-pipenyl-4,6-bis(trichloromethyl)-striazine,
2,4-bis(trichloromethyl)-6-styryl s-triazine,
2-(naphtho)-I-yl)-4,6-bis(chloromethyl)-s-triazine, 2(
4-methoxy-naphtho-l-yl)-4, 6-bis (trichloromethyl)-striazine,
2,4-trichloromethyl-(piperonyl)-6-triazine,
and 2,4-trichloromethyl(4'-methoxystyryl)-6-triazine;
oxime ester compounds such as 1,2-octanedione, 1-[4(
phenylthio)-, 2-(O-benzoyloxime)], and O-(acetyl)-N(
l-phenyl-2-oxo-2-(4'-methoxynaphthyl)
ethylidene) hydroxylamine; phosphine compounds
such as bis(2,4,6-trimethylbenzoyl)phenylphosphine
oxide, and 2,4,6-trimethylbenzoyldiphenylphosphine
oxide; quinone compounds such as 9,10phenanthrenequinone,
camphorquinone, and
ethylanthraquinone; borate compounds; carbazole
compounds; imidazole compounds; and thitanocene
compounds. An oxime derivative (oxime compound) is
effective for improving the resin composition in
sensitivity. These may be used alone or in combination
of two or more thereof.
(Photosensitizer)
It is preferred to use a photosensitizer together
with the photopolymerization initiator. As the
photosensitizer, the following may be used together:
a-acyloxyester, acylphosphine oxide, methylphenyl
44
glyoxylate, benzyl-9,10-phenanthrenequinone,
camphorquinone, ethylanthraquinone, 4,4'diethylisophthalophenone,
3,3' ,4,4'-tetra(tbutylperoxycarbonyl)
benzophenone, 4,4'-
5 diethylaminobenzophenone, or other compound.
The photosensitizer may be incorporated in an
amount of 0.1 to 60 parts by mass for 100 parts by mass
of the photopolymerization initiator.
(Ethylenically Unsaturated Compound)
10 It is preferred to use the photopolymerization
initiator together with an ethylenically unsaturated
compound. The ethylenically unsaturated compound means
a compound having, in the molecule thereof, one or more
ethylenically unsaturated bonds. Of such compounds,
15 preferred is a compound having, in the molecule
thereof, two or more ethylenically unsaturated bonds
because the compound in polymerizability and
crosslinkability are improved, and the difference in
developer-solubility between exposed parts and
20 unexposed parts accompanying the polymerizability and
crosslinkability is distinct. Particularly preferred
is a (meth)acrylate compound having an unsaturated bond
originating from a (meth)acryloyloxy group.
Examples of the compound having, in the molecule
25 thereof, one or more ethylenically unsaturated bonds
include unsaturated carboxylic acids, such as
(meth)acrylic acid, crotonic acid, isocrotonic acid,
45
maleic acid, itaconic acid and citraconic acid, and
alkyl esters thereof; (meth) acrylonitrile;
(meth)acrylamide; and styrene. Typical examples of the
compound having, in the molecule thereof, two or more
5 ethylenically unsaturated bonds include esters each
made from an unsaturated carboxylic acid and a
polyhydroxy compound; (meth)acryloyloxy-groupcontaining
phosphates; urethane (meth)acrylates each
made from a hydroxyl(meth)acrylate compound and a
10 polyisocyanate compound; and epoxy (meth)acrylates each
made from (meth)acrylic acid or a
hydroxyl(meth)acrylate compound, and a polyepoxy
compound.
The above-mentioned photopolymerization initiator,
15 photosensitizer, and ethylenically unsaturated compound
may be added to a composition which contains a
polymerizable liquid crystal compound and which is used
to form a retardation layer that will be described
later.
20 (Polyfunctional Thiol)
A polyfunctional thiol, which functions as a chain
transfer agent, may be incorporated into the
photosensitive colored composition. The polyfunctional
thiol needs only to be a compound having two or more
25 thiol groups. Examples thereof include hexanedithiol,
decanedithiol, 1,4-butanediol bisthiopropionate, 1,4butanediol
bisthioglycolate, ethylene glycol
5
10
46
bisthioglycolate, ethylene glycol bisthiopropionate,
trimethylolpropane tristhioglycolate,
trimethylolpropane tristhiopropionate,
trimetylolpropane tris(3-mercaptobutyrate),
pentaerythritol tetrakisthioglycolate, pentaerythritol
tetrakisthiopropionate, tris(2-hydroxyethyl)
trimercaptopropionate isocyanurate, 1,4dimethylmercaptobenzene,
2,4,6-trimercapto-s-triazine,
and 2-(N,N-dibutylamino)-4,6-dimercapto-s-triazine.
These polyfunctional thiol compounds may be used
alone or in the form of a mixture of two or more
thereof. The polyfunctional thiol may be used, in the
photosensitive colored composition, in an amount
ranging preferably from 0.2 to 150 parts by mass, more
15 preferably from 0.2 to 100 parts by mass for 100 parts
by mass of its pigment.
(Storage Stabilizer)
A storage stabilizer may be incorporated into the
photosensitive color composition to stabilize the
20 composition about' viscosity over time. Examples of the
storage stabilizer include quaternary ammonium
chlorides, such as benzyltrimethylchloride, and
diethylhydroxyamine; organic acids, such as lactic acid
and oxalic acid, and methyl ethers thereof; t-
25 butylpyrocatechol; organic phosphines, such as
triethylphosphine, and triphenylphosphine; and
phosphites. The storage stabilizer may be incorporated
47
into the photosensitive color composition in an amount
of 0.1 to 10 parts by mass for 100 parts by mass of the
pigment therein.
(Tackifier)
5 A tackifier (adhesiveness improver), such as a
silane coupling agent, may be incorporated into the
photosensitive color composition to make the
composition high in adhesiveness to a substrate.
Examples of the silane coupling agent include
10 vinylsilanes such as vinyltris(~-methoxyethoxy)silane,
vinylethoxysilane, and vinylmethoxysilane;
(meth)acrylsilanes such as ymethacryloxypropyltrimethoxysilane;
epoxysilanes such
as ~-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,~-
15 (3,4-epoxycyclohexyl)methyltrimethoxysilane, ~-(3,4epoxycyc1ohexyl)
ethyltriethoxysilane, ~-(3,4epoxycyclohexyl)
methyltriethoxysilane, yglycidoxypropyltrimethoxysilane,
and yglycidoxypropyltriethoxysilane;
aminosilanes such as N-
20 ~(aminoethyl)y-aminopropyltrimethoxysilane,N~(
aminoethyl)y-aminopropyltriethoxysilane,N~(
aminoethyl)y-aminopropylmethyldiethoxysilane,yaminopropyltriethoxysilane,
yaminopropyltrimethoxysilane,
N-phenyl-y-
25 aminopropyltrimethoxysilane, and N-phenyl-yaminopropyltriethoxysilane;
thiosilanes such as ymercaptopropyltrimethoxysilane,
and
48
y-mercaptopropyltriethoxysilane. The silane coupling
agent may be incorporated into the photosensitive
colored composition in an amount of 0.01 to 100 parts
by mass for 100 parts by mass of the pigment therein.
5 (Solvent)
A solvent such as water or an organic solvent may
be blended with the photosensitive color composition to
make the composition coatable evenly onto a substrate.
When the composition used in the embodiment is for a
10 color layer of a color filter, the solvent also has a
function that disperses pigments evenly. Examples of
the solvent include cyclohexanone, ethylcellosolve
acetate, butylcellosolve acetate, 1-methoxy-2-propyl
acetate, diethylene glycol dimethyl ether,
15 ethylbenzene, ethylene glycol diethyl ether, xylene,
ethylcellosolve, methyl-n amyl ketone, propylene glycol
monomethyl ether, toluene, methyl ethyl ketone, ethyl
acetate, methanol, ethanol, isopropyl alcohol, butanol,
isobutyl ketone, and petroleum-based solvents. These
20 may be used alone or in the form of a mixture. The
solvent may be incorporated into the colored
composition in an amount ranging from 800 to 4000 parts
by mass, preferably from 1000 to 2500 parts by mass for
100 parts by mass of the pigment therein.
25 (Organic Pigments)
Usable examples of the pigment that is a red
pigment include C.l. Pigment Reds 7, 9, 14, 41, 48:1,
49
48:2, 48:3, 48:4, 81:1, 81:2, 81:3, 97, 122, 123, 146,
149, 168, 177, 178, 179, 180, 184, 185, 187, 192, 200,
202, 208, 210, 215, 216, 217, 220, 223, 224, 226, 227,
228, 240, 246, 254, 255, 264, 272, and 279.
5 Usable examples of the pigment that is a yellow
pigment include C.l. Pigment Yellows 1, 2, 3, 4, 5, 6,
10, 12, 13, 14, 15, 16, 17, 18, 20, 24, 31, 32, 34, 35,
35:1,36,36:1,37,37:1,40,42,43,53,55,60,61,
62, 63, 65, 73, 74, 77, 81, 83, 86, 93, 94, 95, 97, 98,
10 100, 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,
15 187, 188, 193, 194, 199, 213 and 214.
Usable examples of the pigment that is a blue
pigment include C.l. Pigment Blues 15, 15:1, 15:2,
15:3, 15:4, 15:6, 16, 22, 60, 64, and 80. Of these
pigments, C.l. Pigment Blue 15:6 is preferred.
20 Usable examples of the pigment that is a violet
pigment include C.l. Pigment Violets 1, 19, 23, 27, 29,
30, 32, 37, 40, 42, and 50. Of these pigments, C.l.
Pigment Violet 23 is preferred.
Usable examples of the pigment that is a green
25 pigment include C.l. Pigment Greens 1, 2, 4, 7, 8, 10,
13, 14, 15, 17, 18, 19, 26, 36, 45, 48, 50, 51, 54, 55
and 58. Of these pigments, C.l. Pigment Green 58 is
50
preferred.
Hereinafter, in the description of pigment species
of C.I. Pigments, the species may be abbreviated and
described as follows: PB (Pigment Blue), PV (Pigment
5 Violet), PR (Pigment Red), PY (Pigment Yellow), PG
(Pigment Green), and the like.
(Coloring Material of Light-shielding Layer)
A light-shielding color material contained in the
light-shielding layer or the black matrix is a coloring
10 material having an absorption in the range of visible
ray wavelengths to show a light-shielding function.
Examples of the light-shielding coloring material in
the embodiment include organic pigments, inorganic
pigments, and dyes. Examples of the inorganic pigments
15 include carbon black, and titanium oxide. Examples of
the dyes include azo dyes, anthraquinone dyes,
phthalocyanine dyes, quinoneimine dyes, quinoline dyes,
nitro dyes, carbonyl dyes, and methine dyes. The
organic pigments may be the above-mentioned organic
20 pigments. About the light-shielding component, a
single species thereof may be used, or any combination
of two or more species thereof may be used at any ratio
therebetween. It is also allowable to coat the resin
with the surface of such a coloring material, whereby
25 the light-shielding color material is made higher in
volume resistance, or reversely, raise the content by
percentage of the coloring material in the base
5
10
51
material of the resin to give some quantity of
electroconductivity thereto, whereby the lightshielding
color material is made lower in volume
resistance. However, the volume resistivity of such
the light-shielding material ranges from about 1 x 108
to 1 x 10 15 Qcm; thus, the resistivity is not at a
level that influences the resistance value of the
transparent electroconductive film. Similarly, the
dielectric constant of the light-shielding layer can be
adjusted into the range of 3 to 11 by the selection of
the coloring material, or the content by percentage
thereof.
(Dispersing Agent and Dispersing Aid)
When a polymeric dispersing agent is used as a
15 dispersing agent for the pigments, the pigments
favorably becomes excellent in dispersion stability
over time. Examples of the polymeric dispersing agent
include urethane dispersing agents, polyethyleneimine
dispersing agents, polyoxyethylene alkyl ether
20 dispersing agents, polyoxyethylene glycol diester
dispersing agents, sorbitan aliphatic ester dispersing
agents, and aliphatic-compound-modified polyester
dispersing agents. Particularly preferred is a
dispersing agent made of a graft copolymer containing
25 nitrogen atoms for a light-shielding photosensitive
resin composition used in the embodiment and containing
a large amount of the pigments from the viewpoint of
52
the developability thereof.
Specific examples of these dispersing agents
include EFKA (manufactured by EFKA Co.), Disperbik
(manufactured by BYK Japan K.K.), DISPARLON
5 (manufactured by Kusumoto Chemicals, Ltd.), SOLSPERSE
(manufactured by The Lubrizol Corporation), KP
(manufactured by Shin-Etsu Chemical Co., Ltd.), and
POLYFLOW (manufactured by KYOEISHA CHEMICAL Co., LTD.),
which are each a trade name. These dispersing agents
10 may be used alone, or may be used in any combination of
two or more thereof at any ratio therebetween.
An aid for the dispersion may be, for example, a
colorant derivative. Examples thereof include azo
type, phthalocyanine type, quinacridon type,
15 benzimidazolone type, quinophthalone type,
isoindolinone type, dioxazine type, anthraquinone type,
indanthrene type, perylene type, perynone type,
diketopyrrolopyrrole type, and dioxazine type
derivatives. Of these derivatives, quinophthalone type
20 derivatives are preferred.
A substituent of the colorant derivatives is, for
example, a sulfonic acid group, a sulfonamide group or
a quaternary salt thereof, a phthalimidemethyl group, a
dialkylaminoalkyl group, a hydroxyl group, a carboxyl
25 group, or an amide group that is bonded directly or
through an alkyl, aryl or heterocyclic group, or other
group to the skeleton of the pigment. Of these groups,
53
a sulfonic acid group is preferred. Two or more of
substituents may be bonded to a single pigment
skeleton.
Specific examples of the colorant derivatives
5 include sulfonic acid derivatives of phthalocyanine,
sulfonic acid derivatives of quinophthalone, sulfonic
acid derivatives of anthraquinone, sulfonic acid
derivatives of quinacridon, sulfonic acid derivatives
of diketopyrrole, and sulfonic acid derivatives of
10 dioxazine.
The above-mentioned dispersing aids and colorant
derivatives may be used alone, or in any combination of
two or more thereof at any ratio therebetween.
Hereinafter, various examples of the invention
15 will be described.
In Examples 6 to 9 each related to a color filter
substrate, out of the examples, for each of its color
pixels, three colors of pixels, a red pixel, a green
pixel and a blue pixel, were used. However, a
20 complementary color pixel, such as a yellow pixel, or a
white pixel may be added thereto.
Example 1
A substrate illustrated in FIG. 16 was produced as
follows:
25 (Black-matrix-forming disperse liquid)
In a bead mill dispersing machine were stirred 20
parts by mass of a carbon pigment #47 (manufactured by
54
Mitsubishi Chemical Corporation), 8.3 parts by mass of
a polymeric dispersing agent BYK-182 (manufactured by
BYK Japan K.K.), and 1.0 part by mass of a copper
phthalocyanine derivative (manufactured by TOYO INK
5 CO., LTD.), and 71 parts by mass of propylene glycol
monomethyl ether acetate to prepare a carbon black
disperse liquid.
(Black-matrix-forming photoresist)
A black-matrix-forming resist was formed, using
10 the following materials:
carbon black disperse liquid: pigment #47
(manufactured by Mitsubishi Chemical Corporation),
resin: V259-ME (manufactured by Nippon Steel
Chemical Co., Ltd.) (solid content by percentage: 56.1%
15 by mass),
monomer: DPHA (manufactured by Nippon Kayaku Co.,
Ltd.),
initiators: OXE-02 (manufactured by Ciba Specialty
Chemicals K.K.), and
20 OXE-01 (manufactured by Ciba Specialty
Chemicals K.K.),
solvents: propylene glycol monomethyl ether
acetate, and
25
K.K.)
ethyl 3-ethoxypropionate, and
leveling agent: BYK-330 (manufactured by BYK Japan
These materials were mixed with each other and
55
stirred at composition proportions described below to
prepare a black-matrix-forming resist (pigment
concentration in the solid content: about 20%).
14 parts by mass
5.0 parts by mass
1.5 parts by mass
5
10
Carbon black disperse liquid 3.0 parts by mass
Resin 1.4 parts by mass
Monomer 0.3 part by mass
Initiator OXE-01 0.67 part by mass
Initiator OXE-02 0.17 part by mass
Propylene glycol monomethyl ether acetate
Ethyl 3-ethoxypropionate
Leveling agent
(Black-matrix-forming conditions)
As illustrated in FIG. 16, the above-mentioned
25
15 photoresist was applied onto a transparent substrate 1a
made of glass by spin coating, and a workpiece was
dried to form a coating film having a film thickness of
1.9 pm. This coating film was dried at 100°C for
3 minutes, and then an exposure photomask having
20 openings of a pattern width of 20.5 pm (corresponding
to a streak width of a black matrix) was used for (the
formation of) the black matrix to radiate light from a
super-high-pressure mercury lamp as a light source at
200 mJ/cm2 .
Next, the workpiece was developed with a 2.5%
solution of sodium carbonate for 60 seconds,
sufficiently washed after the development, and further
5
10
56
dried. Thereafter, the workpiece was subjected to
heating treatment at 230°C for 60 minutes to fix the
pattern, thereby forming a black matrix 2, which is the
black matrix, on the transparent substrate 1a. The
streak width of the black matrix 2 was about 20 pm, and
the black matrix was formed surrounding (four-sides)
each rectangular pixel. The inclination angle of an
end of each streak from the transparent substrate plane
was set to about 45 degrees.
(Transparent electroconductive film deposition)
A sputtering machine was used to form a film
thickness of 0.14 pm of transparent electroconductive
film 3 (third electrode) made of ITO (metal-oxide thin
film of indium tin) to cover the entire front surface
15 of the black matrix 2.
(Resin layer formation)
A coating liquid of an alkali-soluble acryl
photosensitive resin was used to form a resin layer 18
to cover the transparent electroconductive film 3 by
20 photolithography in such a manner that the film
thickness of the layer 18 would be 1.8 pm after the
resin turned into a hard film. A photomask used
therein was a mask in which a slit of a half-tone
(transflective region low in transmittance) was made
25 for the center of each of the rectangular pixels. In
this way, a linear concave part 13 in the form of a
rectangle when viewed in plane was formed therein. The
57
depth of the concave part 13 was set to about 1 pm.
The height H1 of convex parts 24 formed above the
black matrix 2 and made of the resin layer 18 was about
1.1 pm. The inclination of the convex parts 24 had an
5 angle of about 45 degrees from the transparent
substrate plane. The height H1 of the convex parts 24
was defined as the height from the front surface of a
flat part of the resin layer 18 to the top of the
convex parts 24.
10 The substrate according to the present example
included no color filter. A color filter may be formed
on the array substrate side (of a display device using
this substrate). Alternatively, the substrate may be
applied to a color liquid crystal display device in a
15 field sequential mode (mode of using plural LED light
sources as a backlight, and attaining a color display,
without using any color filter, by time-sharing lightsource-
driving) .
The acrylic photosensitive resin coating liquid
20 used to form the resin layer 18 was a transparent resin
coating liquid yielded by synthesizing an acrylic resin
as described below, further adding a monomer and a
photoinitiator thereto, and then filtrating of 0.5 pm.
(Acrylic resin synthesis)
25 Into a reactor were put 800 parts by mass of
cyclohexanone. While nitrogen gas was injected
thereinto, the reactor was heated. Thereto was
58
dropwise added a mixture of the following monomers and
thermopolymerization initiator to conduct a
polymerization reaction:
styrene 55 parts by mass,
5 methacrylic acid 65 parts by mass,
methyl methacrylate 65 parts by mass,
benzyl methacrylate 60 parts by mass,
thermopolymerization initiator
15 parts by mass, and
10 chain transfer agent 3 parts by mass
After the addition, the reactor was sufficiently
heated, and thereto was added a solution yielded by
dissolving 2.0 parts by mass of a thermopolymerization
initiator into 50 parts by mass of cyclohexanone. The
15 reaction further continued and a solution of an acrylic
resin was yielded. Cyclohexanone was added to this
resin solution to give a solid content by percentage of
30% by mass to prepare an acrylic resin solution. This
was named a resin solution (1). The weight-average
20 molecular weight of the acrylic resin was about 20,000.
Furthermore, a mixture including the following
composition was stirred and mixed into an even state;
and then glass beads having a diameter of 1 mm were
used to disperse the composition in a sand mill for
25 2 hours, and the resultant was then filtrated through a
filter with a mesh of 0.5 pm to yield a transparent
resin coating liquid:
59
resin solution (1) 100 parts by mass,
polyfucnitonal polymerizable monomer
EO-modified bisphenol A methacrylate
(BPE-500, manufactured by Shin-Nakamura Chemical Co.,
5 Ltd.) 20 parts by mass,
photoinitiator
("Irgacure 907", manufactured by Ciba
Specialty Chemicals K.K.) 16 parts by mass,
and
10 cyclohexanone 190 parts by mass
Example 2
A substrate illustrated in FIG. 17 was produced as
follows:
In the present example, a black-matrix-forming
15 photomask and a photoresist used were the same as in
Example 1.
A black matrix 2 was formed onto a glass substrate
la, and then an acrylic resin for an alkali-soluble and
photosensitive photoresist was coated onto the glass
20 substrate 1a including the black matrix 2 in such a
manner that the film thickness of the resin would be
1.2 ~m after drying. Using a photomask having an
opening width of 10 ~m for only the center of each
photosensitive rectangular pixel, the workpiece was
25 exposed to light, and further developed and subjected
to a film-hardening treatment to form each transparent
linear pattern 22 having a streak width of 12 ~m.
60
Next, a transparent electroconductive film was
laminated thereon in the same way as in Example 1.
Thereafter, a resin layer 18 was formed. A resist
used therefor and a formation method therefor were the
5 same as in Example 1. However, a photomask used for
forming the resin layer 18 was different from that in
Example 1, and a photomask having a linear lightshielding
pattern at the center of each of the
rectangular pixels was used.
10 Referring to FIG. 17, the produced substrate is
described. The film thickness of the resin layer 18 is
1.8 pm. The height of the convex parts 24 of the resin
layer 18 is 1 pm. At the center of each of the
rectangular pixels, the linear pattern 22 made of the
15 transparent resin (acrylic resin) is formed. Above
this linear pattern 22, a concave part 33 is formed
which has an opening width of 7 pm in the transparent
electroconductive film and a depth of about 0.6 pm.
Instead of the acrylic resin used in the present
20 example, the linear pattern may be formed by using a
color layer containing organic pigments at a high
concentration. According to the linear pattern made of
the high-pigment-concentration color layer, leakage of
a light ray in a linear form is eliminated so that
25 display high in color purity can be attained.
61
Example 3
A substrate illustrated in FIG. 18 was produced as
follows:
In the present example, instead of the black-
5 matrix-forming photomask used in Example 1, use was
made of a photomask having not only a black-matrixforming
opening pattern but also an opening having a
width of 11 ~m for the center of each rectangular
pixel. The opening width is made narrow, whereby the
10 light exposure quantity decreases sharply; thus, a
linear light-shielding pattern 32 having a small height
is able to be formed at the center of the rectangular
pixel.
Thereafter, a transparent electroconductive film 3
15 was laminated thereon in the same way as in Example 1.
A photomask used for forming the resin layer 18
was a photomask further including a light-shielding
pattern having a width of 12 ~m for the center of each
of the rectangular pixels. A resist used therefor and
20 a formation method were the same as in Example 1.
Referring to FIG. 18, the produced substrate is
described. Both of The film thicknesses of the resin
layers 18 are 1.8 ~m. The heights of convex parts 24
of the resin layers 18 are 1.1 ~m. At the center of
25 each of the rectangular pixels, the light-shielding
pattern 32 made of the light-shielding layer (blackforming
resist) is formed. Above this light-shielding
62
pattern 32, a concave part 43 is formed which has an
opening width of 7 pm in the transparent
electroconductive film and a depth of about 0.6 pm.
In the present example, the black matrix and the
5 light-shielding pattern at the center of each of the
rectangular pixels were formed by using the single
photomask. However, these may be formed by conducting
a photolithographic method twice, using two independent
photomasks for the black matrix and the light-shielding
10 pattern.
Example 4
A substrate illustrated in FIG. 19 was produced as
follows:
A transparent electroconductive film 3 having a
15 film thickness of 0.14 pm was formed onto a glass
substrate 1a. A black matrix 2 was formed into a film
thickness of 1.9 pm onto the transparent
electroconductive film 3. A black-matrix-forming
photoresist used therefor was the same as in Example 1.
20 Next, a coating liquid of an alkali-soluble
acrylic photosensitive resin was used to form a resin
layer 18 to cover the black matrix 2 and the
rectangular openings in such a manner that the film
thickness of the resin would be 1 pm after the resin
25 turned into a hard film. The height H2 of convex parts
24 of the resin layer 18 formed above the black matrix
2 was set to about 1 pm. The depth of each concave
63
part 53 was 1 ~m, and the transparent electroconductive
film 3 was exposed to the concave part 53.
The substrate according to the present example
includes no color filter. A color filter may be formed
5 on the array substrate side. Alternatively, the
substrate may be applied to a color liquid crystal
display device in a field sequential mode (mode of
using plural LED light sources as a backlight, and
attaining a color display, without using any color
10 filter, by time-sharing light-source-driving) .
The acrylic photosensitive resin coating liquid
used to form the resin layer 18 was the same as used in
Example 1.
Example 5
15 A color filter substrate illustrated in FIG. 20
was produced as follows:
A transparent electroconductive film 3 having a
film thickness of 0.14 ~m was formed above a glass
substrate 1a. A black matrix 2 was formed above a film
20 thickness of 1.9 ~m above the transparent
electroconductive film 3. A black-matrix-forming
photoresist used therefor was the same as in Example 1.
Next, color pixels were formed to cover the black
matrix 2 and the rectangular openings. Color resists
25 used to form the color pixels, and a method for forming
the color pixels are described below.
64
(Formation of color pixels)
«Color-layer-forming disperse liquids»
As organic pigments to be dispersed in the color
layers, the following were used:
5 red pigments: C.I. Pigment Red 254 "IRGAFOR RED
B-CF", manufactured by Ciba Specialty Chemicals K.K.),
and C.I. Pigment Red 177 "CHROMOPHTAL RED A2B",
manufactured by Ciba Specialty Chemicals K.K.);
green pigments: C.I. Pigment Green 58, and C.I.
10 Pigment Yellow 150 ("FANCHON FAST YELLOW Y-5688",
manufactured by Bayer AG); and
blue pigments: C.I. Pigment Blue 15 ("LIONOL BLUE
ES", manufactured by Toyo Ink Co., Ltd.), and C.I.
Pigment Violet 23 ("PALIOGEN VIOLET 5890", manufactured
15 by BASF SE).
These pigments were used to prepare red, green and
blue disperse liquids.

Red pigment: C.I. Pigment Red 254
20 18 parts by mass
Red pigment: C.I. Pigment Red 177
2 parts by mass
Acrylic vanish (solid content by percentage: 20%
by mass) 108 parts by mass
25 A mixture having this composition was stirred into
an even state, and then glass beads were used to
disperse the pigments in a sand mill for 5 hours, and
5
10
15
20
25
65
the resultant was filtrated through a filter with a
mesh of 5 ~m to prepare the red pigment disperse
liquid.

Green pigment: C.I. Pigment Green 58
16 parts by mass
Green pigment: C.I. Pigment Yellow 150
8 parts by mass
Acrylic vanish (solid content by percentage: 20%
by mass) 102 parts by mass
The same preparation method as used for 'the red
pigment disperse liquid was applied to a mixture having
the above-mentioned composition to prepare the green
pigment disperse liquid.

Blue pigment: C.I. Pigment Blue 15
50 parts by mass
Blue pigment: C.I. Pigment Violet 23
2 parts by mass
Dispersing agent ("SOLSPERS" 20000, manufactured
by Zeneca Inc.) 6 parts by mass
Acrylic vanish (solid content by percentage: 20%
by mass) 200 parts by mass
The same preparation method as used for the red
pigment disperse liquid was applied to a mixture having
the above-mentioned composition to prepare the blue
pigment disperse liquid.
66
(Color-pixel-forming color resists)

Red disperse liquid 150 parts by mass
Trimetyhlolpropane triacrylate 13 parts by mass
5 ("TMP3AU
, manufactured by Osaka Organic
Chemical Industry Ltd.)
Photoinitiator 4 parts by mass
("Irgacure 907", manufactured by Ciba
Specialty Chemicals K.K.)
10 Initiator 2 parts by mass
("EAB-FU
, manufactured by Hodogaya Chemical
Co., Ltd.)
Solvent: cyclohexanone 257 parts by mass
A mixture having this composition was stirred and
15 mixed into an even state, and the resultant was
filtrated through a filter with a mesh of 5 pm to
prepare a red-pixel-forming color resist.

Green disperse liquid 126 parts by mass
20 Trimetyhlolpropane triacrylate 14 parts by mass
("TMP3A", manufactured by Osaka Organic
Chemical Industry Ltd.)
Photoinitiator 4 parts by mass
("Irgacure 907", manufactured by Ciba
25 Specialty Chemicals K.K.)
Initiator 2 parts by mass
("EAB-F", manufactured by Hodogaya Chemical
67
Co., Ltd.)
Cyclohexanone 257 parts by mass
A mixture having this composition was stirred and
mixed into an even state, and the resultant was
5 filtrated through a filter with a mesh of 5 ~m to
prepare a green-pixel-forming color resist.

A blue-pixel-forming color resist was formed to be
the composition thereof to have the following
10 composition in the same way as used to form the redpixel-
forming color resist.
Blue disperse liquid 258 parts by mass
Trimetyhlolpropane triacrylate 19 parts by mass
("TMP3A", manufactured by Osaka Organic
15 Chemical Industry Ltd.)
Photoinitiator 4 parts by mass
("Irgacure 907", manufactured by Ciba
Specialty Chemicals K.K.)
Initiator 2 parts by mass
20 ("EAB-F", manufactured by Hodogaya Chemical
Co., Ltd.)
Cyclohexanone 214 parts by mass
«Color pixel formation»
The respective color-pixel-forming color resists
25 yielded by the above-mentioned methods were used to
form color layers.
For the formation of the color layer, spin coating
68
was first used to coat the red-pixel-forming color
resist to give a finish film thickness of 1.8 ~m onto
the glass substrate la above which the transparent
electroconductive film 3 and the black matrix 2 were
5 formed. The workpiece was dried at 90°C for 5 minutes,
and then irradiated through a color-pixel-forming
photomask with light from a high-pressure mercury lamp
at a radiation quantity of 300 mJ/cm2 . The workpiece
was developed with an alkaline developing solution for
10 60 seconds to yield red color pixel 15 in a stripe
form. Thereafter, the workpiece was baked at 230°C for
30 minutes. The pixel was formed to cause the color
part to overlap the BM region by 14.0 ~m. A slit of a
half-tone (transflective part low in transmittance) was
15 arranged for the center of the rectangular pixel to
form a concave part (not illustrated) in a linear form
when the region was viewed in plan. The depth of the
concave part was set to about 1 ~m.
Next, in the same way, the green-pixel-forming
20 color resist was coated to give a finish film thickness
of 1.8 ~m by spin coating. The workpiece was dried at
90°C for 5 minutes, exposed to light through a
photomask to form a pattern in the region adjacent to
the red pixel 15, and then developed to form green
25 pixel 14. In the same way, a slit of a half-tone
(transflective region low in transmittance) was
arranged for the center of the pixel, which was
69
rectangular, to form a concave part 63 in a linear form
when the part 63 was viewed in plan. The depth of the
concave part 63 was set to about 1 pm. Subsequently,
the workpiece was subjected to heat treatment at 230°C
5 for 30 minutes to make the pixel films hard.
Furthermore, about the blue-pixel-forming color
resist, also, in the very same way as about the red and
green, a blue pixel 16 was yielded which had a finish
film thickness of 1.8 pm and was adjacent to each of
10 the red pixels and the green pixel (adjacent to this
red pixel). In this way, a color filter was yielded
which have the color pixels in the three colors, red,
green and blue. Thereafter, the workpiece was
subjected to heat treatment at 230°C for 30 minutes to
15 make the respective pixel-films hard. Thus, a color
filter substrate was yielded.
Thereafter, a resin layer 68 made of a
thermosetting acrylic resin was laminated into a film
thickness of 0.2 pm onto the color pixels. The height
20 of each convex part 64 was about 1 pm, and the depth of
the concave parts 63 was about 0.9 pm. The resin layer
68 made the height of the convex parts 64 and the depth
of the concave part 63 small values, respectively.
Example 6
25 A color filter substrate illustrated in FIG. 21
was produced as follows:
A black matrix 2 was formed into a film thickness
5
70
of 1.9 ~m above a glass substrate 1a. A black-matrixforming
photoresist used therefor was the same as in
Example 1. Next, the color resists used in Example 6
were used to form red color pixel 15, green colored 14
and blue color pixel 16, into a film thickness of
1. 8 ~m.
Thereafter, in the same way as in Example 5, a
sputtering machine was used to form a transparent
electroconductive film 3 into a film thickness of
10 0.14 ~m. Furthermore, an alkali-soluble acrylic
photosensitive resin was used to form a resin layer 78
to give a film thickness of 1.5 ~m after this film was
made hard. At this time, a known photolithographic
method was used to make a concave part 73 having a
15 depth of 1.2 ~m in each of the openings, which were
rectangular. For the formation of the pattern of the
resin layer 78, use was made of a photomask having, at
each of its rectangular openings, a pattern in the form
of a slit. In the present example, the height of
20 convex parts 74 was about 1.1 ~m.
Example 7
A liquid crystal display device according to the
present example is shown in FIG. 22. A color filter
substrate 81 used in the example was the color filter
25 substrate of Example 7, which is illustrated in
FIG. 21. An active-element-formed substrate used in
this example was the array substrate 21 illustrated in
71
FIGS. 8 and 9, which have the comb-teeth-form
electrodes.
This color filter substrate 71 and the array
substrate 21 were laminated to each other, and liquid
5 crystals 77 having negative dielectric constant
anisotropy were sealed in a gap therebetween.
Furthermore, polarizing plates were laminated to both
surfaces thereof, respectively, to produce the liquid
crystal display device illustrated in FIG. 16. On
10 respective surfaces of the color filter substrate 71
and the array substrate 21, vertically alignment films
were beforehand printed and formed. Illustration of
the vertically alignment films is omitted. Without
performing strict alignment treatment necessary for a
15 vertically aligned liquid crystal display device such
as MVA, VATN, or the like (for example, to set a tilt
angle to 89° and perform treatment for alignment in
plural directions to form plural domains), the tilt
angle of the vertical alignment may be about 90°.
20 Referring to FIG. 22, the produced liquid crystal
display device is described. The motions of the liquid
crystals 77 are typically described using a green pixel
14 at the center of FIG. 16.
When a driving voltage is applied, liquid crystal
25 molecules of the liquid crystals 77, in which the
initial alignment is vertical alignment, by a first
electrode 4 and a second electrode 5 (as the
72
above-mentioned comb-teeth-form electrodes), are
inclined into directions from a line which divides the
color pixel 14 from the center of rectangular pixel
into two parts, toward respective shoulder parts 84c of
5 convex parts 84, that is, directions represented by
arrows B. The second electrode regions 5 are each
protruded from an end of the corresponding first
electrode region 4 into a direction represented by
arrows C. Third electrode 3 and the second electrode 2
10 are made into a common potential.
In the present example, a concave part 73 is
present at the center of the green pixel 14, so that in
the color filter plane also, the liquid crystal
molecules are inclined to be divided into two parts
15 from the region passing through the center of
rectangular-pixel. Combined with the effect of the
comb-teeth-form first electrode 4 and second electrode
5 of the array substrate 21, it is possible to attain a
bright display while disclination is restrained.
20 In the present example, the concave part 73 in the
region passing through the center of each of the pixels
improves light transmittance of the device; thus, the
device is optimal for a liquid crystal display device
which puts importance on brightness, such as a
25 transflective type or reflection type display device.
For example, a transflective type liquid crystal
display device can be produced by adding, to a
73
backlight system, a reflective polarizing plate which
transmits light from its backlight and further makes it
possible to reflect external light. The reflective
polarizing plate may be, for example, a member
5 described in Jpn. Pat. Appln. KOKAI Publication
No. 4177398 as a reflective polarizer.
Example 8
A liquid crystal display device according to the
present example is illustrated in FIG. 23. This liquid
10 crystal display device is a transflective type liquid
crystal display device using a reflective polarizing
plate. A color filter substrate 71 used in the example
is the color filter substrate of Example 7, which is
illustrated in FIG. 21. An array substrate on which
15 active elements are formed may be the array substrate
21 as illustrated in FIGS. 8 and 9, which has the combteeth-
form electrodes.
The device has a structure equivalent to the
structure illustrated in FIG. 22, in which the color
20 filter substrate 71 and the array substrate 21 are
arranged to face each other, and the liquid crystals 77
is interposed in a gap therebetween. On a side of the
color filter substrate 71 that is opposite to the
liquid crystals 77, an optical compensation layer 81
25 and a polarizing plate 82a are formed. On a side of
the array substrate 21 that is opposite to the liquid
crystals 77, the following are successively formed: a
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20
25
74
polarizing plate 82b, a light diffusing layer 83a, a
reflective polarizing plate 84, an optical compensation
layer 81b, a prism sheet 85, a light diffusing layer
83b, a light guiding plate 86, and a light reflecting
plate 87. A light source, for example, an LED light
source 88 is attached to the light guiding plate 86.
The LED light source 88 desirably includes RGBindependently
light-emitting elements. However, the
light source 88 may be pseudo-white LEOs. Instead of
the LEOs, a cold cathode ray tube or a fluorescent
lamp, which is ordinarily used in the prior art, may be
used. When the RGB-independently light-emitting
elements are used for the LED light source 88, the
respective emission intensities thereof can be adjusted
independently for each of the colors. Thus, an optimal
color display can be attained. The device may be
applied to a three-dimensional image display.
By use of a substrate which contains no color
filter as used in Example 4, instead of the color
filter substrate, color display can be attained in a
field sequential mode in which LED light sources
emitting RGB rays independently are synchronized with
the liquid crystal display.
Example 9
A color filter substrate illustrated in FIG. 24
was produced as follows:
A black matrix 2 was formed into a film thickness
75
of 1.9 pm above a glass substrate 1a. A black-matrixforming
photoresist used therefor was the same as in
Example 5. Next, the color resists used in Example 6
were used to form red color pixel 15, green color pixel
5 14 and blue color pixel 16 into a film thickness of
1.8 pm. A photomask used to form each of the color
pixels was a photomask having light-shielding patterns
along respective central lines which divide a part
corresponding to each of the rectangular pixels into
10 two parts. In this way, a liner concave part of 10 pm
in width and 1.8 pm in depth was made at the center of
each of the color pixels.
Thereafter, in the same way as in Example 5, a
sputtering machine was used to form a transparent
15 electroconductive film 3 into a film thickness of
0.14 pm to cover the red color pixel 15, the green
color pixel 14 and the blue color pixel 16.
Next, a solution of a thermosetting type acrylic
resin was used to form a resin layer 98 to give a film
20 thickness of 0.8 pm after the resin was made into a
hard film. As a result, each convex part 94 was formed
which was an overlap part made of the black matrix 2,
the color pixels 14, 15 and 16, the transparent
electroconductive film 3, and the resin layer 98.
25 Moreover, a linear concave part 93 was formed at the
center of each of the rectangular pixels. The height
H3 of the convex parts 94 was about 1 pm, and the depth
5
15
10
76
of the concave parts 93 was 0.7 ~m.
When the color filter substrate according to the
present example is used for a reflection type display
device, the linear concave part 93 at the center of
each of the pixels can function as an opening for
improving the pixel in brightness. In the case of
transmission display using a backlight, light leakage
from the backlight can be restrained by forming TFT
interconnects (for example, drain-drawing interconnects
or auxiliary capacitor interconnects) as a lightshielding
membrane at positions where the interconnects
are to overlap the linear concave parts when viewed in
plan.
Example 10
A color filter substrate illustrated in FIG. 25
was produced in the same way as in Example 5 except
that the resin layer 68 made of the thermosetting type
acrylic resin was not formed above the color pixels 14,
15 or 16.
20 Example 11
A color filter substrate illustrated in FIG. 26
was produced as follows:
A black-matrix-forming photomask and photoresist
used in the present example were the same as those in
25 Example 1.
A black matrix 2 was formed above a glass
substrate la, and then an acrylic resin of an
77
alkali-soluble and photosensitive photoresist was
coated above the glass substrate 1a including the black
matrix 2 in such a manner that the film thickness of
the resin would be 1.2 pm after the workpiece was
5 dried. Using a photomask having an opening width of
10 pm for only the center of each photosensitive
rectangular pixel, the workpiece was exposed to light,
and further developed and subjected to a film-hardening
treatment to form each transparent linear pattern 22
10 having a pixel line width of 12 pm.
Next, a transparent electroconductive film 3 was
laminated thereon in the same way as in Example 1.
Thereafter, color pixels were formed. Color
resists used therefor, and formation methods therefor
15 were the same as those in Example 5. However, a colorpixel-
forming photomask used therefor, which is
different from those in Example 5, is a photomask in
which a linear light-shielding pattern is present at
the center of the rectangular pixel.
20 Referring to FIG. 26, the produced color filter
substrate is described. The film thickness of each of
red pixel 15, green pixel 14 and blue pixel 16 is
1.8 pm. The height of convex part 24, which is an
overlap part of two of the color layers, is 1 pm. The
25 linear pattern 22, which is firmed by the transparent
resin (acrylic resin), is formed at the center of each
of the rectangular pixels. A concave part 33 having an
78
opening width of 7 ~m in the transparent
electroconductive film and a depth of about 0.6 ~m is
made above the linear pattern 22.
The linear pattern may be formed by use of a color
5 layer containing organic pigments at a concentration
higher than the pigment concentration in the color
pixels instead of the acrylic resin used in the present
example. This linear pattern, which is the color layer
having the higher pigment concentration, makes it
10 possible to prevent leakage of a light ray in a linear
form to attain a high color-purity display.
Example 12
A color filter substrate illustrated in FIG. 27
was produced as follows:
15 In the present example, instead of the blackmatrix-
forming photomask used in Example 1, a photomask
having not only a black-matrix-forming opening pattern
but also an opening having a width of 11 ~m for the
center of each rectangular pixel, was used. Since the
20 opening width was made narrow, the light exposure
quantity was able to be sharply reduced; thus, a linear
light-shielding pattern 32 having a small height can be
formed at the center of the rectangular pixel.
Thereafter, a transparent electroconductive film 3
25 was laminated thereon in the same way as in Example 1.
A color-pixel-forming photomask used was a
photomask having a light-shielding pattern further
5
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15
20
25
79
having a width of 12 ~m for the center of the
rectangular pixel. Color resists and production
methods used were the same as in Examples 5 and 11.
Referring to FIG. 27, the produced color filter
substrate is described. The film thickness of each of
red pixel 15, green pixel 14 and blue pixel 16 is
1.8 ~m. The height of convex part 24, which is an
overlap part of two of the color layers, is 1.1 ~m.
The linear pattern 32, which is the light-shielding
layer (black-forming resist), is formed at the center
of each of the rectangular pixels. A concave part 43
having an opening width of 7 ~m in the transparent
electroconductive film and a depth of about 0.6 ~m is
formed above the light-shielding pattern 32.
In the present example, the black matrix and the
light-shielding pattern at the center of the
rectangular pixel were formed by the single photomask.
However, the black matrix and the light-shielding
pattern may be formed by performing a photolithographic
method twice, using two independent photomasks.
Example 13
A color filter substrate illustrated in FIG. 28
was produced as follows:
In the present example, materials and production
methods used to form a black matrix and color pixels
were made the same as in Examples 5 and 10. However, a
photomask used to form the color pixel is a photomask
80
having an opening for each rectangular pixel part
(photomask having neither half-tone nor linear lightshielding
pattern for the center of the rectangular
pixel) .
5 Referring to FIG. 28, the produced color filter
substrate is described. The film thickness of each of
red pixel 15, green pixel 14 and blue pixel 16 is
1.8 pm. The height of the convex part 24, which is an
overlap part of two of the color layers, is 1 pm. The
10 present example is formed to have a structure in which
a protecting layer 50 made of a thermosetting type
acrylic resin is laminated into a film thickness of
0.3 pm over the color filter.
Example 14
15 The color filter substrate according to Example 13
and an array substrate on which active elements of TFTs
were formed were laminated to each other, and then
liquid crystals having negative dielectric constant
anisotropy were sealed in a gap therebetween.
20 Furthermore, polarizing plates were laminated to both
surfaces thereof, respectively, to produce a liquid
crystal display device illustrated in FIG. 29. On
respective surfaces of the color filter substrate and
the array substrate, vertically alignment films were
25 beforehand printed and formed. The active-elementformed
substrate was an array substrate which had combteeth-
form elements as illustrated in FIGS. 14 and 15.
5
10
15
20
25
81
Illustration of the vertically alignment films is
omitted. Without performing a strict alignment
treatment necessary for a vertically aligned liquid
crystal display device such as MVA, VATN, or the like
(for example, to set the tilt angle to 890 and perform
treatment for alignment in plural directions to form
plural domains), vertical alignment giving the tilt
angle of about 900 was performed.
Referring to FIG. 29, the produced liquid crystal
display device is described. The motions of liquid
crystals 67 are typically described by green pixel 14
at the center of FIG. 29.
When a driving voltage is applied, liquid crystal
molecules of the liquid crystals 67, in which the
initial alignment is vertical alignment, by a first
electrode 4 and a second electrode 5 (as the combteeth-
form electrodes), are inclined into directions
from a line which divides the color pixel 14 from the
center of the rectangular pixel into two parts, toward
respective shoulder parts 14c, that is, directions
represented by arrows B. The second electrodes 5 are
each shifted from the corresponding first electrode 4
into a direction represented by arrows C. Third
electrode 3 and the second electrode 2 may be a common
potential.
Example 15
A liquid crystal display device according to the
82
present example is illustrated in FIG. 30. A color
filter substrate 11 used in the example was a substrate
yielded by laminating a protecting layer 50 made of a
thermosetting type acrylic resin into a film thickness
5 of 0.2 pm above a color filter substrate having the
same structure as Example 10. An array substrate 21
was an array substrate having the same structure as
Example 14.
The liquid crystal display device illustrated in
10 FIG. 30 was produced by laminating the color filter
substrate 11 and the array substrate 21, on which a
vertically alignment film was beforehand formed, onto
each other, forming the liquid crystals 67 having
negative dielectric constant anisotropy into a gap
15 therebetween, and further laminating polarizing plates
onto both surfaces thereof, respectively. Illustration
of the vertically alignment films is omitted. Without
performing a strict alignment treatment necessary for a
vertically aligned liquid crystal display device such
20 as MVA, VATN, or the like (for example, to set the tilt
angle to 89° and perform treatment for alignment in
plural directions to form plural domains), vertical
alignment giving the tilt angle of about 90° was
performed.
25 Referring to FIG. 30, the produced liquid crystal
display device is described. The motions of the liquid
crystals 67 are typically described using a green pixel
83
14 at the center of FIG. 30.
When a driving voltage is applied, liquid crystal
molecules of the liquid crystals 67, in which the
initial alignment is vertical alignment, by a first
5 electrode 4 and a second electrode 5 (as the combteeth-
form electrodes), are inclined into directions
from a line which divides the color pixel 14 from the
center of the rectangular pixel into two parts, toward
respective shoulder parts 14c, that is, directions
10 represented by arrows B. The second electrodes 5 are
each shifted from the corresponding first electrode
region 4 into a direction represented by arrows C.
Third electrode 3 and second electrode 2 may be a
common potential.
15 In the present example, a concave part 63 is
present at the center of the green pixel 14, so that in
the color filter plane also, the liquid crystal
molecules are inclined to be divided from the center of
the rectangular-pixel into two parts. Combined with
20 the effect of the comb-teeth-form first electrode 4 and
second electrode 5 of the array substrate 21, it is
possible to attain a bright display while disclination
is restrained. In the present example, the concave
part 63 at the center improves light transmittance of
25 the device; thus, the device is optimal for a liquid
crystal display device in which puts importance on
brightness, such as a transflective type or reflection
5
10
15
20
25
84
type device. For example, a transflective type liquid
crystal display device can be produced by adding, to a
backlight system, a reflective polarizing plate which
transmits light from its backlight and further makes it
possible to reflect external light. The reflective
polarizing plate may be, for example, a member as a
reflective polarizer described in Jpn. Pat. Appln.
KOKAI Publication No. 4177398.
Example 16
A liquid crystal display device according to the
present example is illustrated in FIGS. 31 and 32. In
the liquid crystal display device according to the
example, two TFTs (not illustrated) are arranged as
active elements in each pixel.
FIGS. 31 and 32 are each a sectional view of a
green pixel region in which a TFTI and a TFT2 are
arranged in each of the pixels, respectively. First
electrodes PI and P3 are connected to the TFTl; and
second electrodes P2 and P4 to the TFT2. For the
convenience of description, as illustrated in the
figures, this green pixel is divided into a normal
display region and a dynamic display region.
Hereinafter, a description will be made about the
driving of liquid crystal molecules in a half region of
the pixel. The green pixel is formed to have a small
film thickness at the center of the green pixel in the
same way as in Example 5 illustrated in FIG. 20.
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25
85
FIG. 31 illustrates the alignment of the liquid
crystal molecules in the state that a driving signal is
sent to the TFTI so that a driving voltage is applied
only to the first electrodes PI and P3. In this case,
liquid crystal molecules Ll, L2 and L3 in the normal
display region are sufficiently inclined so that the
region can gain a sufficient transmittance. However,
liquid crystal molecules L4, L5 and L6 in the dynamic
display region at the center of the pixel are
insufficiently inclined so that the region is in a low
transmittance state.
FIG. 32 illustrates the alignment of the liquid
crystal molecules in the state that a driving signal is
sent also to the TFT2 so that a driving voltage is
applied to the first electrodes P2 and P4. In this
case, in the liquid crystal molecules L4, L5 and L6 in
the dynamic display region at the center of the pixel,
as well as the liquid crystal molecules Ll, L2 and L3
in the normal display region, are sufficiently inclined
so that the dynamic display region turns high in
transmittance. In this case, the part of the pixel
center is formed to have a small film thickness, so
that transmitted light is increased to make it possible
to attain a very bright display (dynamic display).
The liquid crystal display devices according to
the embodiments and examples described hereinbefore
each make it possible to decrease alignment treatments
86
for its color filter substrate and its array substrate,
and further improve the response of its liquid
crystals. Moreover, its structure in which convex and
concave parts and first and second electrodes are
5 formed makes it possible to decrease the disclination
of the liquid crystals to enhance the display of the
liquid crystals.
Furthermore, the display device can be formed to
have a structure in which a transparent
10 electroconductive film is laminated to cover effective
display pixels of its color filter; thus, the following
liquid crystal display device can be supplied as a
secondary advantageous effect: a device in which an
external electric field is not easily affected, the
15 mode of this device is different from the IPS mode (of
driving liquid crystals by effect of a transverse
electric field) or the FFS mode (of driving liquid
crystals by effect of an electric field generated in
fringes of comb-teeth-form electrodes) .
20 Each of the pixels of the liquid crystal display
devices according to the above-mentioned embodiments
and examples is divided into 1/2-pixels that are
linearly symmetrical with each other, or 1/4-pixels
that are centrosymmetrical with each other about the
25 linear concave part. However, by forming 2 to 4 TFTs
in each of the pixels and further adopting a driving
mode of applying different voltages thereto, the
5
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25
87
viewing angle can be adjusted or a three-dimensional
image can be displayed.
Reference Signs List
la, and lb ... transparent substrates
2 black matrix
3 transparent electrode (third electrode)
4 first electrode(s)
5 second electrode(s)
11, and 71 ... color filter substrates
14 ... green pixel
14a, 14b, 14c and 84c ... shoulder part
15 red pixel
16 blue pixel
17, 27, 67 and 77 ... liquid crystals
17a, 17b, 17c, and 17d... liquid crystal molecules
18, 68, 78 and 98 ... resin layers
21 ... array electrode
23, 33, 43, 53, 63, 83 and 93 ... concave parts
24, 64, 74, 84 and 94 ... convex parts
81a and 81b optical compensation layers
82a and b polarizing plates
83a and 83b light diffusing layers
84 reflective polarizing plate
85 prism sheet
86 light guiding sheet
87 light reflecting plate
88 LED light source

CLAIMS
1. A substrate for a liquid crystal display
device, characterized by comprising:
a transparent substrate, and a black matrix, a
5 transparent electroconductive film and a resin layer
that are each formed above the transparent substrate,
wherein the black matrix is a light-shielding layer in
which light-shielding pigments are dispersed in a
resin, and comprises openings; and
10 the resin layer is formed above the transparent
substrate comprising the black matrix and the
transparent electroconductive film, comprises a convex
part above the black matrix, and comprises, in a region
that passes through a center of each of the openings in
15 the black matrix, a concave part.
2. The liquid crystal display device substrate of
claim 1,
characterized in that the concave part is in a
linear form or cross form when viewed in plan.
3. The liquid crystal display device substrate of
claim 1,
characterized in that the transparent
electroconductive film is formed to cover the black
matrix and the openings, and the resin layer is formed
25 above the transparent electroconductive film.
4. The liquid crystal display device substrate of
claim 1,
89
characterized in that the transparent
electroconductive film is formed above the transparent
substrate, the black matrix is formed above the
transparent electroconductive film, and the resin layer
5 is formed above the transparent electroconductive film
and the black matrix.
5. The liquid crystal display device substrate of
claim 1,
characterized in that a linear convex part pattern
10 comprising the transparent resin is formed between the
transparent substrate and the transparent
electroconductive film, and at the center of each of
the openings in the black matrix.
6. The liquid crystal display device substrate of
15 claim 1,
characterized in that a linear convex part lightshielding
pattern comprising a same material as used
for the black matrix is formed between the transparent
substrate and the transparent electroconductive film,
20 and at the center of each of the openings in the black
matrix.
7. The liquid crystal display device substrate of
claim 1,
characterized in that color pixels comprising at
25 least a red pixel, a green pixel, and a blue pixel are
formed in each of the openings in the black matrix, and
the transparent electroconductive film is formed above
90
the color pixels.
8. The liquid crystal display device substrate of
claim 1,
characterized in that color pixels comprising at
5 least a red pixel, a green pixel, and a blue pixel are
formed in each of the openings in the black matrix via
to interpose the transparent electroconductive film
therebetween.
9. A substrate for a liquid crystal display
10 device, characterized by comprising:
a transparent substrate;
a black matrix which is formed above the
transparent substrate, is a light-shielding layer in
which light-shielding pigments are dispersed in a
15 resin, and comprises openings;
a transparent electroconductive film which is
formed above the transparent substrate comprising the
black matrix; and
color pixels having colors which are formed in
20 each of pixel regions divided by the openings, and is
formed above the transparent electroconductive film.
10. The liquid crystal display device substrate
of claim 9,
characterized in that the black matrix comprises
25 an inclined side surface.
11. The liquid crystal display device substrate of
claim 9,
5
15
10
91
characterized in that respective adjacent ends of
the color pixels each having the colors form an overlap
part above the transparent electroconductive film and
above a part corresponding to the black matrix;
a total of a film thickness of the overlap part
and that of the black matrix is larger than that of
each of the color pixels; and
the overlap part forms a convex part protruded
from a surface of the color pixel.
12. The liquid crystal display device substrate
of claim 9,
characterized In that the color pixel comprises,
at a central part thereof, a linear concave part.
13. A liquid crystal display device,
characterized by comprising:
the liquid crystal display device substrate of
claim 1;
an array substrate which is arranged opposite to
the liquid crystal display device substrate, and
20 comprising liquid-crystal-driving elements arranged in
a matrix form thereon; and
liquid crystals which are held between the liquid
crystal display device substrate and the array
substrate.
25 14. The liquid crystal display device of
claim 13,
characterized in that the array substrate
92
comprises a first electrode and a second electrode to
which different electric potentials are applied in
order to drive each rectangular pixel.
15. The liquid crystal display device of
5 claim 14,
characterized in that when a voltage for driving
the liquid crystals are applied to the first and second
electrodes, liquid crystal molecules act to be inclined
from the concave part of the resin layer into a
10 direction which is parallel to the concave part and is
a direction toward the black matrix near the liquid
crystal molecules when viewed in plan.
16. The liquid crystal display device of
claim 15,
15 characterized in that when a driving voltage is
applied to the first electrode, and the second
electrode and a third electrode, the third electrode
being the transparent electroconductive film, liquid
crystal molecules in each of the pixel regions of the
20 liquid crystal display device act to be inclined into
reverse directions which are linearly symmetrically to
a straight line by which the pixel region is divided
into two parts.
17. The liquid crystal display device of
25 claim 14,
characterized in that the first electrode and/or
the second electrode is/are not arranged at a position
93
of the array substrate which corresponds to a center of
a width of a pattern of the black matrix.
18. The liquid crystal display device according
to claim 14,
5 characterized in that the first electrode is
formed at a position other than a position which
corresponds to a center of a width of a pixel line of
the black matrix.
19. The liquid crystal display device of
10 claim 14,
characterized in that the first electrode of the
array substrate is an electrode comprises a comb-teeth
pattern connected to an active element that drives the
liquid crystals; and
15 the second electrode which is an electrode
comprising a comb-teeth pattern similar to that of the
first electrode is formed below the first electrode via
an insulating layer, and is protruded from an end of
the first electrode into a direction along which the
20 liquid crystals are inclined.
20. The liquid crystal display device of
claim 14,
characterized in that the first and second
electrodes each comprise electroconductive metal-oxides
25 which is transparent in a range of visible wavelengths.
21. The liquid crystal display device of
claim 13,
94
characterized in that the liquid crystals have
negative dielectric constant anisotropy.
22. A liquid crystal display device,
characterized by comprising:
5 a color filter substrate and an array substrate,
wherein the color filter substrate and the array
substrate are opposed and stuck to each other via
liquid crystals,
the color filter substrate comprises a black
10 matrix having rectangular openings, a transparent
electroconductive film, color pixels, and a resin layer
above a transparent substrate,
the array substrate comprises elements driving the
liquid crystals and being arranged in a matrix form,
15 the resin layer is arranged directly or indirectly
above the transparent electroconductive film,
a convex part protruded from a surface of the
resin layer is formed,
a convex part is formed in a region that passes
20 through a center of each of the rectangular openings in
the black matrix,
the array substrate comprises a comb-teeth-form
first electrode and a comb-teeth-form second electrode
each of which comprises electroconductive metal-oxides
25 which is transparent in a range of visible wavelengths,
the second electrode is arranged below the first
electrode via an insulating layer between the first and
5
95
second electrodes, and
the second electrode is protruded from an end of
the first electrode into a direction along which the
liquid crystals are inclined.
23. The liquid crystal display device of
claim 22,
characterized in that the concave part is in a
linear form or a cross form when viewed in plan.
24. The liquid crystal display device of
10 claim 22,
characterized in that two to four elements that
drive the liquid crystals are arranged for each of the
pixels, and the two to four elements are connected to
different electrodes, respectively.
Dated this 23rd day of November 2012
t
Ana~dvocales
Agents for the Applicant