JP3245008B2 - Color liquid crystal display device and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color liquid crystal display device, and more particularly to a color liquid crystal display device having a color filter partitioned by a black matrix and a method of manufacturing the same.

[0002]

2. Description of the Related Art Liquid crystal display devices are classified into a simple matrix type and an active matrix type according to the difference in the pixel selection method.

In a simple matrix type liquid crystal display device, a liquid crystal such as STN is sealed between two sets of intersecting electrodes, and pixels are formed at the intersections of the electrodes.

On the other hand, an active matrix type liquid crystal display device has a nonlinear element (switching element) corresponding to each of a plurality of pixel electrodes arranged in a matrix.
Since the liquid crystal in each pixel is theoretically always driven (duty ratio: 1/1) theoretically, the active mode has a higher contrast than the simple matrix mode which adopts the time-division driving mode. It is becoming an indispensable technology especially for color liquid crystal display devices. As a typical switching element, a thin film transistor (TFT) is known.

The basic structure of a liquid crystal display device is such that a liquid crystal composition is filled between one substrate on which a common pixel electrode is formed and the other substrate on which individual electrodes or switching elements are formed. A color liquid crystal display device is configured by providing a color filter on the substrate side.

FIG. 8 is an exploded perspective view showing each component of a liquid crystal module employing a TFT type liquid crystal display device as an example of a color liquid crystal display device to which the present invention is applied.
SHD is a frame-shaped shield case (metal frame) made of a metal plate, LCW is a liquid crystal display window as its display area,
PNL is a liquid crystal display panel, SPB is a light diffusion plate, MFR is an intermediate frame, PCB3 is an inverter circuit, BL is a backlight, BLS is a backlight support, LCA is a lower case, and the upper and lower arrangement as shown in the figure. In this connection, the respective members are stacked to assemble the liquid crystal module MDL.

[0007] The module MDL is a shield case SH.
The whole is fixed by a claw CL and a hook FK provided on D.

The intermediate frame MFR is formed in a frame shape so that an opening corresponding to the display window LCW is formed, and the frame portion has a shape corresponding to the shape and thickness of the diffusion plate SPB, the backlight support BLS, and various circuit components. Irregularities and openings for heat dissipation are provided.

The lower case LCA also serves as a reflector for backlight, and has a reflection ridge RM corresponding to the fluorescent tube BL so that efficient reflection can be performed.

[0010] The backlight is not limited to the back lighting system shown in the figure, but may employ a side lighting system in which a light source is arranged on the side surface of the liquid crystal display panel PNL. In this case, a surface light source structure mainly including a light guide is provided below the diffusion plate SPB.

FIG. 9 is a sectional view for explaining an example of the structure of a conventional TFT type liquid crystal display device, which comprises a lower glass substrate SUB1 and an upper glass substrate SUB2 with a liquid crystal composition layer LC interposed therebetween.

On the lower glass substrate SUB1 side, a gate electrode GT, gate insulating films AOF and GI, a semiconductor layer AS,
It has a thin film transistor TFT1 composed of source / drain electrodes SD1 and SD2 and a transparent pixel electrode ITO1, and further has a protective film PSV1 and a lower alignment film ORI1 laminated thereon.

The upper glass substrate SUB2 has a black matrix BM serving as a light shielding film and a color filter FIL.
(R), FIL (G), FIL (B), protective film PSV
2. A common transparent pixel electrode ITO2 (COM) and an upper alignment film ORI2 are laminated.

Note that a silicon oxide film SIO is provided on the opposing surface of the lower glass substrate SUB1 and the upper glass substrate SUB2, and the above-described layers are stacked on the silicon oxide film SIO.

A seal pattern SL made of an epoxy resin or the like is provided between the lower glass substrate SUB1 and the upper glass substrate SUB2 so as to seal the liquid crystal composition layer LC except for the liquid crystal filling port along the edges. It is.

The common transparent pixel electrode ITO2 (COM) on the side of the upper glass substrate SUB2 is connected to a lead-out wiring INT formed on the lower glass substrate SUB1 with a silver paste material AGP at at least one place (four corners in the figure). I have. The lead wiring INT is formed in the same manufacturing process as the gate terminal and the drain terminal (not shown).

The alignment films ORI1, ORI2, the transparent pixel electrode ITO1, and the common transparent pixel electrode ITO2 are formed inside the seal pattern SL.

The polarizing plates POL1 and POL2 are formed on the outer surfaces of the lower glass substrate SUB1 and the upper glass substrate SUB2, respectively.

The liquid crystal composition layer LC is sealed in a region partitioned by a seal pattern SL between the lower alignment film ORI1 and the upper alignment film ORI2 for setting the direction of liquid crystal molecules. The lower alignment film ORI1 is formed above the protective film PSV1 on the lower glass substrate SUB1 side.

The liquid crystal display device has a lower glass substrate SUB1.
The above-described layers are stacked on the side of the upper glass substrate SUB2 and the upper glass substrate SUB2, respectively.
Formed on the UB2 side, and the lower transparent glass substrate SUB1
Are superposed on each other, liquid crystal is injected from the opening of the seal pattern SL, the injection port is sealed with an epoxy resin or the like to form a liquid crystal composition layer, and then the lower glass substrate SUB1 and the upper glass substrate SUB2 are cut at predetermined locations. Is obtained.

Therefore, the i-type semiconductor layer AS of the thin film transistor TFT1 is sandwiched between the upper and lower black matrixes BM, which are light-shielding films, and the gate electrodes GT, so that external natural light or backlight does not hit. The black matrix BM is formed in a grid around each color pixel, and each grid partitions an effective area of one color pixel. Thereby, the outline of each color pixel becomes clear, and the contrast is improved. That is, the black matrix BM has the function of shielding the i-type semiconductor layer AS and improving the contrast.

The black matrix BM extends outside the seal pattern SL to prevent reflected light from entering the display area.

A plurality of color filters FIL (generally, red (R): FIL (R), green (G): FIL (G), blue (B): FIL ( B) is adopted, but yellow, magenta, and cyan, which are complementary colors to each other, are also arranged) according to a predetermined rule. For example,
The color filter FIL (G) is the upper glass substrate SUB2
A predetermined area is defined by a configuration in which the black matrix BM is partially overlapped and surrounds the periphery thereof.

Conventionally, a black matrix is formed by depositing a metal chromium or the like and then obtaining a lattice pattern by a photo-etching method, or by adding a coloring agent for blackening into a photosensitive resin and applying the same to a photolithography. A method of forming a lattice pattern by using a process and the like are known.

The color filter is formed mainly by a dyeing method using a photolithography process, a pigment dispersion method, an electrodeposition method, a printing method, or the like.

In a pigment dispersion method using a photolithography process as a typical method for forming a black matrix and a color filter, a black matrix is first formed and then a predetermined pigment (for example, a red pigment) is dispersed. Applying a conductive material on the black matrix,
The red filter is formed by exposing and developing through a mask having an opening only in the red filter region, and green and blue filters are sequentially formed in the same manner.

FIG. 10 is a schematic cross-sectional view of a main part for explaining a structure of a color filter portion formed by a pigment dispersion method using a photolithography process, where SUB2 is an upper glass substrate, SIO is a silicon oxide film, and BM is a BM. Black matrix, FIL (R), FIL (G), FIL (B)
Is a colored pixel, PSV2 is a protective film layer, ITO
2 is a transparent electrode.

As shown in FIG.
IL (R), FIL (G), and FIL (B) are separated by a black matrix BM, covered with a protective film layer PSV2, and have a transparent electrode ITO2 formed on the top.

A liquid crystal display of this type is disclosed in, for example, JP-A-63-309921.

[0030]

The color filter in the liquid crystal display device according to the prior art is formed by forming a black matrix BM and applying a photosensitive material in which a predetermined pigment is dispersed on the black matrix. Since it is formed by exposing and developing through a mask having an opening only in a predetermined filter region, the color filters FIL (R), FIL (G), and FIL are formed.
There is a problem that each exposure mask having a predetermined opening is required for each (B), and the number of processes is increased because each development step is required.

Further, as shown in FIG. 10, there is another problem that the surface of each filter is not uniform and it is difficult to maintain the uniformity of the film thickness.

A first object of the present invention is to provide a color liquid crystal display device in which a so-called color filter substrate having a black matrix and a color filter has a flat surface in contact with a liquid crystal composition layer to achieve high image quality. .

A second object of the present invention is to provide a liquid crystal display device having a color filter structure which does not require a plurality of coloring steps, has a uniform thickness of a plurality of color filters, and has good flatness. It is to provide a manufacturing method of.

[0034]

In order to achieve the first object, a first aspect of the present invention is directed to a first aspect of the present invention, wherein a pair of substrates, a black matrix formed on one of the pair of substrates and the black matrix are provided. In a liquid crystal display device having at least a color filter layer partitioned by a matrix and a liquid crystal composition layer interposed between the pair of substrates, the black matrix may be a styrene-maleic anhydride copolymer.
A colored base layer comprising a resin having a hydroxyethyl acrylate modified product as a main component, a dye carbon, a pigment, and a sensitizer, wherein the color filter layer comprises a styrene-maleic anhydride copolymer; The black matrix formed on the one of the substrates, and the coloring base layer by thermal transfer only between the black matrix and the pattern of the black matrix. Is filled with a color filter layer colored in a pattern of three primary colors, a transparent protective film layer on the black matrix and the color filter layer, and a transparent electrode formed on the protective film layer. And characterized in that:

According to a second aspect of the present invention, in the first aspect, the maximum thickness difference between the black matrix and the three primary color base layers is 0.1 μm. It is characterized by the following.

In order to achieve the first object, a third aspect of the present invention is directed to the first or second aspect, wherein the black matrix and the colored base layer have a groove at a contact portion thereof. A transparent protective film layer on the black matrix and the colored base layer; and a transparent electrode formed on the protective film layer.

According to a fourth aspect of the present invention, there is provided the fourth aspect of the present invention, except that a groove formed in a contact portion between the black matrix and the colored base layer is removed. The maximum thickness difference between the flat portions of the black matrix and the three primary color base layers is 0.1 μm or less.

In order to achieve the first object, a fifth aspect of the present invention is directed to any one of the first to fourth aspects, wherein the black matrix has an optical wavelength range of 400 to 70.
The extinction coefficient is 1 (μm ⁻¹ ) or more in the range of 0 nm, and the thickness of the black matrix is in the range of 0.8 to 2.0 μm.

In order to achieve the first object, the sixth invention of claim 6 is the invention according to any one of the first to fifth inventions, wherein each of the three primary colors of the colored base layer comprising the three primary colors is red,
It is characterized by being one of a set of green and blue, or a set of yellow, magenta and cyan.

According to a seventh aspect of the present invention, in order to achieve the second object, a pair of substrates, a black matrix formed on one of the pair of substrates, and a black matrix are defined. In a method for manufacturing a liquid crystal display device having at least a color filter layer and a liquid crystal composition layer interposed between the pair of substrates, a styrene-maleic anhydride copolymer of 2-styrene may be provided on one of the pair of substrates.
After forming a coating film composed of a resin mainly composed of a modified hydroxyethyl acrylate, a dye carbon, a pigment, and a sensitizer, exposure is performed through an exposure mask having a predetermined pattern, development is performed, and a black matrix is formed. And forming a coloring base composed of a resin having a styrene-maleic anhydride copolymer modified with 2-hydroxyethyl acrylate as a main component on the black matrix, using the black matrix as a mask. A step of exposing the back surface from the side opposite to the colored base application surface of the substrate and developing to form a pattern of the dye base for the three primary colors, and a pattern of the dye base layer from the three primary colors by a thermal transfer method. And a coloring step of coloring the colored layer.

[0041]

In the constitution of the first aspect of the present invention, the black matrix is made of a resin mainly composed of a modified styrene-maleic anhydride copolymer of 2-hydroxyethyl acrylate, a dye carbon, a pigment and a sensitizer. A pattern of a black matrix formed on one substrate by using a color base layer constituting a color filter layer as a resin containing a styrene-maleic anhydride copolymer modified with 2-hydroxyethyl acrylate as a main component. The color base layer is filled with a color filter layer colored in a pattern of three primary colors by a thermal transfer method only between the layers, so that the surface in contact with the liquid crystal composition layer becomes flat and the display quality is improved.

In the structure of the second aspect of the present invention, when the maximum thickness difference between the black matrix and the three primary color base layers is 0.1 μm or less, the surface is further flattened and the display quality is improved.

In the structure of the third aspect of the present invention, the features of the present invention can be structurally identified by providing a groove at the contact portion between the black matrix and the coloring base layer.

In the structure of the fourth invention, the maximum film thickness difference between the flat portion of the black matrix and the three primary color base layers except for the groove formed in the contact portion between the black matrix and the color base layer is different. When the thickness is 0.1 μm or less, the surface is further flattened, and the display quality is improved.

In the fifth aspect of the present invention, the black matrix has an extinction coefficient of 1 (μm ⁻¹ ) or more in a light wavelength range of 400 to 700 nm and a film thickness of 0.8 to 2.0 μm.
, A thin and high-quality display can be obtained.

In the constitution of the sixth aspect, each of the three primary colors of the colored base layer composed of the three primary colors is a set of red, green, and blue;
Alternatively, a full-color image can be displayed by using any one of a set of yellow, magenta, and cyan.

In the structure according to the seventh aspect of the present invention, one of the pair of substrates is provided with a resin containing a styrene-maleic anhydride copolymer modified with 2-hydroxyethyl acrylate as a main component, a dye carbon, a pigment, And after forming a coating film comprising a sensitizer, exposing through a light exposure mask having a predetermined pattern, and developing to form a black matrix, styrene-on the black matrix,
A surface opposite to the surface of the substrate on which the colored base is applied is formed by applying a colored base composed of a resin mainly composed of a modified 2-hydroxyethyl acrylate of a maleic anhydride copolymer and using the black matrix as a mask. A manufacturing method including at least a step of exposing a back surface from the side and developing to form a pattern of a dye base for three primary colors, and a coloring step of coloring the pattern of the dye base layer into a colored layer composed of three primary colors by a thermal transfer method. By doing so, the process can be simplified and a high quality filter substrate can be obtained.

[0048]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In all the drawings, components having the same function are denoted by the same reference numerals, and their repeated description is omitted.

FIG. 1 is a schematic cross-sectional view of a main part of a first embodiment of a color filter substrate in a liquid crystal display device according to the present invention. In FIG. 1, ITO2 is a transparent electrode formed on the surface of the color filter, PSV2. Denotes a transparent protective film formed on the colored layer, FIL (R), FIL (G), F
IL (B) is a colored pixel portion (color pixel, color filter), SUB2 is an upper glass substrate, BM is a black matrix, and SIO is a silicon oxide film.

The silicon oxide film SIO may not be formed depending on the use of the liquid crystal display device or the material of the upper glass substrate SUB2.

In the figure, an upper glass substrate SUB2, which is a color filter substrate constituting a liquid crystal display device, has a silicon oxide film SIO on a surface facing a lower glass substrate (not shown) and a black matrix BM thereon. Three-color color filters FIL (R), FIL partitioned
(G) and FIL (B) are formed.

The black matrix BM is made of styrene-
A resin having a 2-hydroxyethyl acrylate modified product of a maleic anhydride copolymer as a main component, and a dye carbon,
It is formed by a photolithography process in which a photosensitive material comprising a pigment and a sensitizer is applied, exposed through an exposure mask having a predetermined lattice pattern, and developed. The color filter is formed by coloring a coloring layer filled in the opening of the black matrix BM by a sublimation thermal transfer method. The colored layer is styrene-
It is made of a resin mainly composed of a modified maleic anhydride copolymer of 2-hydroxyethyl acrylate.

The above color filters FIL (R), FI
L (G) and FIL (B) are substantially equal to the film thickness of the black matrix BM and form a substantially flat surface.

Then, a transparent protective film layer PSV is formed on the black matrix and the coloring layer (color filter).
2 and a transparent electrode ITO formed on this protective film layer
2 is provided.

According to the structure of this embodiment, the film thicknesses of the black matrix and the color filter are substantially equal to each other. Therefore, the flatness of the protective film layer PSV2 and the transparent electrode ITO2 formed on this protective film layer is reduced. Is good, and the overall thickness can be reduced.

Next, a method of manufacturing the color filter according to the embodiment of the present invention will be described.

FIG. 2 is a process chart for explaining one embodiment of a method for manufacturing a color filter constituting a liquid crystal display device according to the present invention.

First, (a) a black matrix BM is formed directly on the upper glass substrate SUB2 or on a silicon oxide film coated on the glass substrate by a photolithography process. Here, the upper glass substrate SUB2
A black matrix BM is formed on the silicon oxide layer SIO.

As a material of the black matrix BM,
Using a DCF-K series (trade name) manufactured by Nippon Kayaku Co., Ltd., the composition is applied by a spinner, exposed through an exposure mask having predetermined openings, and developed.

The DCF-K series is a resin obtained by blending a resin mainly composed of a modified styrene-maleic anhydride copolymer of 2-hydroxyethyl acrylate with a dye carbon, a pigment and a sensitizer. The details of the composition ratio and characteristics of the main components and the like relating to the DCF-K series are described in JP-A-6-35188.

The DCF-K series has an optical wavelength range of 400
It has a characteristic of an absorption coefficient of 1 (μm ⁻¹ ) or more at ７００700 nm.

In this embodiment, the spinner rotation speed at the time of applying the black matrix material was set to 300 to 1000 rpm, and a thin film having a thickness of 0.8 to 2.0 μm was formed in 15 seconds.

After the applied thin film of the black matrix material is dried at 100 ° C. for 5 minutes, it is exposed to light at a wavelength of 365 nm and a light amount of 10 to ²⁰ mW / cm ² for about 10 seconds.

After exposure, a pattern is formed by shaking in a developing solution using a dedicated developing solution manufactured by Nippon Kayaku Co., Ltd., washed with pure water by a shower method, and baked at 200 to 230 ° C. for 10 minutes. .

In the black matrix BM thus formed, the variation in the thickness of the effective pixel area is 0.1 μm.
m.

In this embodiment, the exposure wavelength in the photolithography process for forming the black matrix BM is limited to the above-described one. However, the present invention is not limited to this. Exposure.

(B) The dye base layer 1 is formed on the black matrix pattern BM by spinner coating. The CFR series (trade name) manufactured by Nippon Kayaku Co., Ltd. was used as a material of the dyeing base.

This CFR series is, similarly to the DCF-K series, a styrene-maleic anhydride copolymer.
-A resin mainly composed of a modified hydroxyethyl acrylate. Since the dyeing base has good affinity with the black matrix BM due to the similarity in physical properties of these materials, the applied dyeing base coats the entire surface of the substrate without being repelled by the black matrix BM.

In this embodiment, the spinner rotation speed at the time of application of the dyeing base was set to 500 to 1300 rpm, and 15 seconds.
A coating film having a thickness of 0.8 to 2.0 μm was formed.

After the applied dyed base material layer 1 is dried at 100 ° C. for 5 minutes, back exposure from an ultraviolet light source 5 is used to perform a single exposure and development process using the opening pattern of the black matrix BM as a mask. A dye base pattern of three primary colors is formed at a time. Through the development step, the dye base on the black matrix BM is removed.

Accordingly, the cross-sectional shape of the dye base layer 1 is substantially the same over the entire effective pixel region, and a three-primary-color dye base pattern having excellent flatness can be obtained.

As described in the section of the prior art, a color filter forming process of a pigment dispersion system and a dyeing system, which is currently mainstream, exposes three primary color layers three times.
While the thickness difference between the three primary color layers formed in the development step is 0.2 to 0.6 μm, the dye base pattern of the three primary colors is formed at one time by one exposure and development step. In the manufacturing method of the present embodiment, it is apparent that the difference in the thickness of the colored layer is reduced in principle.

The exposure conditions for the dyeing base pattern are as follows:
The pattern was formed by shaking in a developing solution using a special developing solution manufactured by Nippon Kayaku Co., Ltd. for development at 5 nm, a light amount of 10 to ²⁰ mW / cm ² and an exposure time of 10 seconds.

The thickness of the dye base layer 1 does not depend on the thickness of the black matrix BM, and can be set to an arbitrary thickness by changing the spinner rotation speed, the amount of exposure light and the exposure time during coating.

In this embodiment, the exposure wavelength is limited by the photolithography process of the dye base layer 1.
Alternatively, a plurality of wavelengths or continuous wavelengths may be used. By the way, it is desirable to remove the dyeing base material adhered to the outside of the outermost peripheral pattern of the black matrix BM because there is a possibility that the dyeing material may enter the effective pixel portion as a foreign substance when the glass substrate is cut. In this embodiment, a square black-frame light shielding plate (not shown) is provided between the upper glass substrate SUB2 and the ultraviolet light source 5 so as to cover the surrounding dyeing base. The ultraviolet rays pass through only the portion, and the ultraviolet rays impinge on the pixel forming portion. According to this method, the peripheral dyeing base layer 1 can be removed at the same time as forming the filter pattern of each color during development.

(C) After the dye base layer 1 is formed, the dye base layer 1 is partially heated by a heating element 4 such as a thermal head through a thermal transfer film 2 on which a sublimable dye 3 has been applied in advance, and the dye sublimation property is utilized. Then, the dye base layer 1 is colored to form a pattern of color filters FIL (R), FIL (G), FIL (B). The pattern of each of the color filters may be formed by a single heating process for each color using a two-dimensional array of heating elements corresponding to the surface arrangement of the pattern, or a one-dimensional pattern corresponding to the one-dimensional arrangement of the pattern. The heating elements in the array are sequentially moved to predetermined color filter positions, and are subjected to a plurality of rotations of heat treatment to develop color. In any of the heating methods, it goes without saying that heating is performed using a thermal transfer film coated with a sublimation dye of each color for each color.

In this example, a commercially available disperse dye, cationic dye or the like manufactured by Nippon Kayaku Co., Ltd. was used as the sublimable dye 3.

For example, for red, Kayaset Red B or Kayaset Scarlet 926, for green, a mixture of Kayaset Yellow AG and Kayaset Blue 714,
Kayaset Blue 714 is used for blue.

When yellow, magenta and cyan are formed as color filters, Kayaset Yellow AG is used for yellow, Kayaset Blue 714 for cyan, and Kayaset Red B for magenta. I do.

As a method of partially heating the thermal transfer film, a method of performing partial sublimation thermal transfer by partially heating the thermal transfer film by irradiating light energy such as laser or the like in addition to using a thermal head as the heating element 4 is used. You may.

Further, according to the production method of this embodiment, since the dyeing base does not remain on the surface of the black matrix BM, the effect of preventing the color mixing of the sublimable dye 3 in the horizontal direction is high.

(D) FIL (R), FIL (G), FIL of color filters formed by coloring by thermal transfer
A protective film PSV is formed to cover the pattern (B).

This protective film PSV has functions of improving heat resistance and chemical resistance as a color filter, preventing liquid crystal contamination and flattening.

In particular, regarding the heat resistance, since the color filter uses a sublimable dye, decoloring occurs from the colored dye base layer near the sublimation temperature of the dye, which is observed as deterioration of the color filter. . Therefore, the protective film layer PSV is formed on the coloring layer (color filter pattern) in order to prevent vertical diffusion and sublimation of the dye.

An epoxy resin was used as the material of the protective film PSV. In addition, an organic material such as an acrylic resin or a polyimide resin, or an inorganic material such as SiO may be used.

(E) A transparent electrode IT is formed on the protective film PSV2.
O2 (Common electrode: Com) is formed by sputtering,
A predetermined pattern is formed using a photolithography process.

In the active matrix, there is a method in which the transparent electrode ITO is formed by concealing the peripheral portion of the substrate where the transparent electrode ITO is not formed in advance by using a mask having an opening in the center, and then performing film formation by sputtering or the like. In some cases, pattern formation by a photolithography process is not performed as in this embodiment.

According to the present embodiment, the manufacturing process can be shortened for simultaneously forming the dye base layers 1 constituting a plurality of color filter layers, and the difference in film thickness between the black matrix layer and the color filter layer is reduced. As a result, a high-quality image can be obtained by improving the flatness of the black matrix layer and the color filter layer.

In the first embodiment of the present invention, the number of spinner rotations and the amount of light for back exposure during the formation process of the dye base pattern 1 are adjusted to thereby provide a second method described below.
Black matrix BM and dye base layer 1 as in Example
Can be controlled within 0.1 μm to further improve the flatness of the surface.

FIG. 3 is a schematic cross-sectional view of a main part of a color filter in a liquid crystal display device according to a second embodiment of the present invention, illustrating a cross-sectional view of a contact portion between a black matrix having a color filter structure and a dye base layer. FIG.

[0092] In the figure, the black matrix BM
Is shown to be thicker than the dye base layer 1 which becomes the color filter layer FIL, but the reverse may be the case. For example, in the case of a super twisted nematic liquid crystal display device, it is necessary to control the variation of the thickness of the liquid crystal layer with respect to the center value within 0.1 μm in order to improve the contrast and the color tone.

At present, in the mainstream color filter forming process using a pigment dispersion method or a dyeing method, the difference in film thickness between the black matrix and the colored layer is about 0.5 μm, and the difference in the film thickness of the three primary color colored layers is flat. Protective film PS
The thickness of V must be increased.

Therefore, as described in the first embodiment, if the three primary color dyeing base patterns have substantially the same shape and the maximum film thickness difference between the black matrix BM and the dyeing base layer 1 can be further reduced, it is even more significant. The flatness is improved, and the thickness of the protective film layer can be reduced, which contributes to the improvement of the transmittance of the color filter.

However, it is necessary that the thickness of the protective film is sufficient to satisfy the specifications required for the protective film, such as heat resistance, chemical resistance, and prevention of liquid crystal contamination.

In this embodiment, the thickness of the black matrix BM was set to 1.0 μm using the DCF-K series. The process conditions were a rotation speed of 800 rpm, an exposure light amount of 15 mW / cm ² , and an exposure time of 10 seconds.

In order to make the film thickness of the dye base layer 1 the same as that of the black matrix BM, the process conditions were as follows: the number of rotations was 1100 rpm, the light amount was 15 mW / cm ² , and the exposure time was 10 seconds.

As described above, by adjusting the spinner rotation speed, the amount of exposure light, and the exposure time during coating, the manufacturing process can be shortened in order to simultaneously form the dye base layers 1 constituting a plurality of color filter layers, and In addition, the thickness difference between the black matrix layer and the color filter layer can be further reduced, and the flatness between the black matrix layer and the color filter layer can be made extremely good, so that a higher quality image can be obtained.

FIG. 4 is a schematic cross-sectional view of a main part of a liquid crystal display device according to a third embodiment of the present invention, illustrating a structure of a color filter, in which a black matrix having a color filter structure and a color filter layer (dying base layer) 2 shows a schematic cross-sectional view of the contact portion of FIG. The same reference numerals as those in FIG. 1 correspond to the same parts.

In the figure, when a black matrix BM is patterned on a transparent substrate (image substrate) SUB2 by a photolithography process, the processed shape is adjusted by adjusting the amount of exposure light, development conditions, and post-bake conditions. And a quasi-tapered shape having an angle of 20 to 80 degrees.

FIG. 5 is a schematic view of a photograph of a cross section of the black matrix processed portion taken by a scanning electron microscope.

As shown in the figure, the color filters FIL (R), FIL (G),
When the dyeing base layer 1 to be the FIL (B) is applied and the dyeing base layer pattern is formed by back exposure using the black matrix BM as a mask, a tapered portion that becomes a groove is formed at the contact portion between the black matrix and the dyeing base layer. T is formed.

The color filter FIL (R), FIL (G), FIL
Step of obtaining (B), protective film PSV and transparent electrode IT
The step of forming O is the same as in the first embodiment.

The color filter FIL is provided on the upper image substrate PSV2 on which the black matrix BM of this embodiment is formed.
(R), FIL (G), and FIL (B) are coated with the dye base layer 1 and the process parameters are adjusted as described in the second embodiment, whereby the black matrix BM is formed.
The difference between the maximum film thickness of the dye base layer 1 and the black matrix B
Except for the groove V formed in the contact portion between M and the dye base layer 1,
By controlling the thickness within 0.1 μm, the flatness of the surface can be improved.

FIG. 6 is a schematic cross-sectional view of the contact portion between the black matrix layer and the dye base layer of the color filter substrate of the third embodiment of the liquid crystal display device according to the present invention.

As shown in the figure, a groove V is formed at the close contact portion between the black matrix BM and the dye base layer 1 which will be the filter FIL.

The groove V has a shape showing the features of the manufacturing method according to the present invention, and the presence or absence of the groove V serves as an index for identifying whether or not the color filter substrate is manufactured according to the present invention.

In FIG. 6, the thickness of the black matrix BM is shown to be thicker than that of the dye base layer 1, but the reverse is also possible.

FIG. 7 is a simulated view of a photograph taken by a scanning electron microscope of a contact portion between the black matrix BM and the dye base layer 1, and (a) and (b) show cross sections.

According to this embodiment, the manufacturing process can be shortened for simultaneously forming the dye base layers 1 constituting a plurality of color filter layers, and the difference in film thickness between the black matrix layer and the color filter layer can be further reduced. And the flatness of the black matrix layer and the color filter layer is extremely good, so that a higher quality image can be obtained.

Further, the above-described black matrix BM
There is also an effect that the manufacturing method is specified by the groove V formed in the close contact portion of the dye base layer 1.

Further, the groove V is later filled with a protective film PSV having good heat resistance to planarize the surface of the protective film.

The depth of the groove V can be controlled by adjusting the exposure conditions and post-baking conditions when forming the pattern of the dye base layer 1 and adjusting the taper shape of the black matrix BM.

Note that the present invention is not limited to an active matrix type color liquid crystal display device such as a TFT type, but can be similarly applied to a simple matrix type color liquid crystal display device such as an STN type.

[0115]

As described above, according to the present invention,
The production process can be shortened by simultaneously forming the dye base layer serving as the color filter on the color filter substrate constituting the liquid crystal display device.

Further, the difference in film thickness between the black matrix layer and the color filter layer that define the color filter layer is reduced, and the flatness of the upper glass substrate opposite to the liquid crystal composition layer is extremely improved. Obtainable.

Further, the above-described black matrix BM
The manufacturing method can be specified by the groove V formed in the close contact portion between the dye base layer 1 and the dye base layer 1.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a main part for explaining a structure of a first embodiment of a color filter substrate in a liquid crystal display device according to the present invention.

FIG. 2 is a process diagram illustrating one embodiment of a method of manufacturing a color filter constituting a liquid crystal display device according to the present invention.

FIG. 3 is a schematic cross-sectional view of a main part, illustrating a structure of a second embodiment of a color filter in a liquid crystal display device according to the present invention.

FIG. 4 is a schematic cross-sectional view of a main part, illustrating a structure of a third embodiment of a color filter in a liquid crystal display device according to the present invention.

FIG. 5 is a schematic view of a photograph taken by a scanning electron microscope of a cross section of a black matrix processed portion of a color filter in a liquid crystal display device according to a third embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view of a contact portion between a black matrix layer and a dye base layer of a color filter substrate of a third embodiment of the liquid crystal display device according to the present invention.

FIG. 7 is a schematic view of a photograph taken by a scanning electron microscope of a contact portion between a black matrix and a dye base layer in a third embodiment of the liquid crystal display device according to the present invention.

FIG. 8 is an exploded perspective view showing each component of a liquid crystal module employing a TFT type liquid crystal display device as an example of a color liquid crystal display device to which the present invention is applied.

FIG. 9 is a cross-sectional view illustrating a structural example of a conventional TFT liquid crystal display device.

FIG. 10 is a schematic cross-sectional view of a main part illustrating a structure of a color filter portion formed by a pigment dispersion method using a photolithography process.

[Description of Signs] LC liquid crystal composition layer SUB1 Lower glass substrate SUB2 Upper glass substrate GT Gate electrode AOF, GI Gate insulating film AS Semiconductor layer SDI, SD2 Source / drain electrode TFT Thin film transistor ITO1 Transparent pixel electrode PSV1, PSV2 Protective film ORI1, ORI2 Lower alignment film BM Black matrix FIL (R), FIL (G), FIL (B) Color filter T Taper V groove.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshifumi Tomita 3300 Hayano, Mobara City, Chiba Prefecture Electronic Devices Division, Hitachi, Ltd. (72) Inventor Nobuyuki Nimura 3-43-19 Shimo, Kita-ku, Tokyo (72) Inventor Masao Onishi 3-26-8 Shimo, Kita-ku, Tokyo (72) Inventor Hirokazu Kano 3-26-8 Shimo, Kita-ku, Tokyo (56) References JP-A-8-295808 (JP, A) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/1335 G02B 5/20

Claims (7)

(57) [Claims] At least a pair of substrates, a black matrix formed on one of the pair of substrates, a color filter layer partitioned by the black matrix, and a liquid crystal composition layer interposed between the pair of substrates. In the liquid crystal display device, the black matrix comprises a resin having a styrene-maleic anhydride copolymer-modified 2-hydroxyethyl acrylate as a main component, a dye carbon, a pigment, and a sensitizer; The color base layer constituting the filter layer is made of a resin containing a styrene-maleic anhydride copolymer-modified 2-hydroxyethyl acrylate as a main component, and the black formed on the one substrate Only in the space between the matrix and the pattern of the black matrix, the colored base layer has a pattern of three primary colors by a thermal transfer method. And a transparent protective film layer formed on the black matrix and the color filter layer, and a transparent electrode formed on the protective film layer. A color liquid crystal display device. 2. The method according to claim 1, wherein the maximum thickness difference between said black matrix and said three primary color base layers is 0.1 μm.
A color liquid crystal display device characterized by the following. 3. The method according to claim 1, wherein a groove is formed at a contact portion between the black matrix and the coloring base layer, and a transparent protective film layer is provided on the black matrix and the coloring base layer. A color liquid crystal display device comprising: a transparent electrode formed on a protective film layer. 4. A maximum film thickness difference between a flat portion of the black matrix and the three primary color base layers, excluding a groove formed in a close contact portion between the black matrix and the color base layer. Is less than or equal to 0.1 μm. 5. The black matrix according to claim 1, wherein the black matrix has an extinction coefficient of 1 (μm ⁻¹ ) or more in a light wavelength range of 400 to 700 nm, and the black matrix has a thickness of 0.1 μm. A color liquid crystal display device having a thickness in the range of 8 to 2.0 μm. 6. The color base layer according to any one of claims 1 to 5, wherein each of the three primary colors of the colored base layer is a set of red, green, and blue, or a set of yellow, magenta, and cyan. A color liquid crystal display device comprising: 7. At least a pair of substrates, a black matrix formed on one of the pair of substrates, a color filter layer partitioned by the black matrix, and a liquid crystal composition layer interposed between the pair of substrates. In a method for manufacturing a liquid crystal display device, a resin having a 2-hydroxyethyl acrylate-modified styrene-maleic anhydride copolymer as a main component, a dye carbon, a pigment, and sensitization are provided on one of the pair of substrates. Forming a coating film made of an agent, exposing through a light exposure mask having a predetermined pattern, and developing to form a black matrix; and forming a styrene-maleic anhydride copolymer on the black matrix. -A coloring base composed of a resin containing a modified hydroxyethyl acrylate as a main component is applied and formed, and the black matrix is formed. Forming a pattern of the dye base for the three primary colors by performing back exposure from the side opposite to the color base application surface of the substrate using the mask as a mask, and developing the pattern of the dye base layer by a thermal transfer method. And a coloring step of coloring a colored layer composed of three primary colors by the method described above.