JPH04265901A - Production of color filter - Google Patents

Abstract

PURPOSE:To provide the process for producing color filters by which the color filters used for flat displays, such as liquid crystal displays and imagers, such as CCD, or color sensors, etc., are efficiently obtained with high accuracy. CONSTITUTION:In the process for producing the color filters having colored layers 16 consisting of colored patterns of plural colors and black matrices 14, a photosensitive layer 13 is formed by applying a transparent material which exhibits tacky adhesiveness when exposed on a transparent substrate 12 and thereafter, the black matrices 14 are formed by exposing the photosensitive layer 13 via a photomask having patterns for the black matrices and sticking a concealing powder material to the exposed parts and the colored layers 16 are formed by repeating the stage for exposing the photosensitive layer 13 via a photomask having prescribed patterns and sticking a colored powder material to the exposed parts to form colored patterns, for the required number of colors.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for manufacturing color filters, and in particular, to manufacture color filters for use in flat displays such as liquid crystal displays, imagers such as CCDs, color sensors, etc. with high precision and efficiency. The present invention relates to a method of manufacturing a color filter that can be obtained easily.

0002

2. Description of the Related Art For example, the image pickup tube of a color video camera is equipped with a color filter in which fine stripes of a plurality of colors are formed on a transparent substrate. Furthermore, in liquid crystal displays (LCDs), color filters are used in both active matrix and simple matrix systems in order to meet the recent demand for colorization. For example, a thin film transistor (
In active matrix liquid crystal displays using TFT, the color filters are red (R) and green (G).
The three primary colors of , blue (B) are used, and by turning on and off the electrodes corresponding to each pixel of R, G, and B, the liquid crystal operates as a shutter and lights each pixel of R, G, and B. Transparent color display is performed. And the color mixture is 2
This is visually performed on the retina using the principle of additive color mixing, in which liquid crystal shutters corresponding to pixels of more than one color are opened and colors are mixed to appear as different colors.

[0003] Color filters used as described above have conventionally been manufactured using methods such as dyeing methods and dispersion methods. Here, the production of color filters by the dyeing method is performed, for example, as follows. That is, a coating solution containing a hydrophilic resin such as gelatin, casein, or polyvinyl alcohol added with a photosensitive agent such as dichromate is applied onto a transparent glass substrate by spin coating or the like, and then a mask with a predetermined pattern is applied. Exposure and development are carried out using
Thereafter, it is dyed with a dye to form a first colored layer. Thereafter, a resist dyeing layer is provided on the first colored layer to prevent double dyeing, and then a second colored layer and a third colored layer are respectively formed in the same manner as the first colored layer. As a result, a color filter including R, G, and B colored layers on a transparent glass substrate can be obtained.

[0004] Color filters are manufactured using the dispersion method, for example, as follows. That is,
A photosensitive liquid in which a coloring agent such as an organic pigment or an inorganic pigment is dispersed in a transparent photosensitive resin is applied onto a transparent glass substrate to form a photosensitive resin layer. Next, a mask having an opening pattern of a predetermined shape is placed on this photosensitive resin layer, and exposure and development are performed to form a first colored layer. Similarly, a second colored layer and a third colored layer can be formed to obtain a color filter including R, G, and B colored layers.

[0005]

[Problems to be Solved by the Invention] However, while the dyeing method provides a color filter with a rich variety of tones and excellent resolution, it is difficult to prevent the already colored areas from being dyed twice during dyeing. There was a problem that the process was complicated and the manufacturing cost was high due to the need to take countermeasures. Furthermore, since dyes are used as colorants, there is also a problem that heat resistance, chemical resistance, light resistance, etc. are inferior.

[0006]Also, although the dispersion method allows the formation of fine patterns with high heat resistance and light resistance, it requires a photolithography process every time the color is changed, making the process complicated. There was a problem in that it was difficult to reduce manufacturing costs. Against this background, a printing method has been proposed as a method of manufacturing color filters that allows cost reduction and mass production at the same time, and also allows for larger screens. Conventionally proposed printing methods include offset methods such as lithographic offset printing and intaglio offset printing, screen printing methods, and flexo printing methods.

However, the printing method has the problem that the printed shape deteriorates due to thickening or thinning of pixels, generation of pinholes, etc., and it is particularly difficult to reproduce fine patterns. In addition, since the thickness of particularly thin lines cannot be made sufficiently,
For example, it is not suitable for manufacturing a color filter having a colored pattern such as a black matrix that requires light-shielding properties. Therefore, when manufacturing a color filter with a high-quality black matrix,
It was necessary to form a black matrix by a costly chromium vapor deposition method or the like. Furthermore, in conventional printing methods, when ink is transferred from the blanket to the glass substrate, only a portion of the ink is transferred, resulting in splits within the ink layer, resulting in the ink surface not being smooth after printing. was there. Furthermore, since the process is unstable, if printing is continued continuously, there is a problem that the printed film thickness changes and the printed shape deteriorates.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to produce color filters used in flat displays such as liquid crystal displays, imagers such as CCDs, color sensors, etc. with high precision and efficiency. It is an object of the present invention to provide a method for manufacturing a color filter that can be obtained.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method for manufacturing a color filter comprising a colored layer consisting of a colored pattern of a plurality of colors and a black matrix, which develops tackiness upon exposure to light. After coating a photosensitive material on a transparent substrate to form a photosensitive layer, the photosensitive layer is exposed to light through a photomask having a pattern for a black matrix, and a concealing powder material is attached to the exposed area to form a black matrix. The process of forming a colored pattern by exposing the photosensitive layer to light through a photomask having a predetermined pattern and depositing a colored powder substance on the exposed portion is repeated for the required number of colors to form a colored layer. The structure is as follows.

0010

[Operation] The photosensitive layer formed on the transparent substrate is exposed to light through a photomask having a black matrix pattern, and the exposed areas develop tackiness, and a concealing powder substance is attached to the exposed areas to make the photosensitive layer black. A matrix is formed, and the photosensitive layer is exposed to light through a photomask having a predetermined pattern to develop tackiness in the exposed areas, and a colored powder substance is attached to the exposed areas to form a colored pattern. By repeating this process, a color filter including a colored layer having a colored pattern of a plurality of colors as required can be obtained. This makes it possible to manufacture color filters that can form fine patterns, and
The color filter process is simplified and manufacturing costs can be reduced.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an example of an active matrix liquid crystal display (LCD) using a color filter manufactured according to the present invention, and FIG. 2 is a schematic cross-sectional view. 1 and 2, the LCD 1 includes a color filter 10 and a transparent glass substrate 20.
A liquid crystal layer 40 made of twisted nematic (TN) liquid crystal and having a thickness of approximately 5 to 10 μm is formed between the color filter 10 and the color filter 10 .
Polarizing plates 50 and 51 are arranged on the outside of a transparent glass substrate 20.

FIG. 3 is an enlarged partial sectional view of the color filter 10, which includes a transparent substrate 12 and a black matrix 14 formed on the transparent substrate 12.
, a colored layer 16 , a protective layer 18 provided to cover the black matrix 14 and the colored layer 16 , and a transparent common electrode 19 . This color filter 10 is arranged so that the transparent common electrode 19 is located on the liquid crystal layer 40 side. The colored layer 16 includes a red pattern 16R, a green pattern 16G, and a blue pattern 16B, and the colored patterns are arranged in a mosaic arrangement as shown in FIG. Note that the arrangement of the colored patterns is not limited to this, and may be a triangular arrangement, a striped arrangement, or the like.

Further, display electrodes 22 are provided on the transparent glass substrate 20 so as to correspond to the colored patterns 16R, 16G, and 16B, and each display electrode 22 has a thin film transistor (TFT) 24. Furthermore, scanning lines (gate electrode bus lines) 26 a and data lines 26 b are arranged between each display electrode 22 so as to correspond to the black matrix 14 .

In such an LCD 1, each of the colored patterns 16R, 16G, and 16B constitutes a pixel, and the liquid crystal is turned on and off by turning on and off the display electrode corresponding to each pixel while illumination light is irradiated from the polarizing plate 51 side. The layer 40 operates as a shutter, and light is transmitted through each pixel of the colored patterns 16R, 16G, and 16B to perform color display. As the transparent substrate 12 of the color filter 10, a rigid material without flexibility such as quartz glass, Pyrex glass, or a synthetic quartz plate, or a flexible material with flexibility such as a transparent resin film or an optical resin plate is used. be able to. Among these, Corning's 7059 glass is a material with a low coefficient of thermal expansion, and has excellent dimensional stability and workability in high-temperature heat treatment.Also, since it is an alkali-free glass that does not contain any alkali components, it is a material with a low coefficient of thermal expansion. Suitable for matrix type LCD color filters.

In the present invention, the black matrix 14 and the colored layer 16 are formed on the transparent substrate 12 using a photosensitive material that develops adhesiveness when exposed to light. Here, an example of manufacturing a color filter according to the present invention will be described with reference to FIGS. 4 and 5. First, a photosensitive material is applied onto a transparent substrate 12 to form a photosensitive layer 13 with a thickness of about 0.5 to 5 μm (
Figure 4(A)). Next, the photosensitive layer 13 is exposed to light through a photomask for a black matrix to develop adhesiveness in the exposed portion 13a (FIG. 4(B)). Then, a concealing powder material is scattered on the photosensitive layer 13 (FIG. 4(C)), and the concealing powder material is attached to the exposed portion 13a, and the excess concealing powder material is blown off to form a black matrix 14 (FIG. 4(C)). (D)). Next, the photosensitive layer 13 is exposed through a photomask for a red pattern to expose the exposed portion 13b.
to develop adhesion (Fig. 5(A)). Then, a red powder substance is scattered on the photosensitive layer 13 (FIG. 5(B)), and the red powder substance is attached to the exposed portion 13b, and the excess red powder substance is blown away to form a red pattern 16R (FIG. 5(B)). (C)). Similarly, a green pattern 16G is formed by exposing to light through a photomask for a green pattern to deposit a green powder substance (FIG. 5(D)), and exposing to light through a photomask for a blue pattern to deposit a green powder substance. A substance is deposited to form a blue pattern 16B (FIG. 5(E)).

[0016] By omitting the black matrix forming step in the above manufacturing process, a color filter without a black matrix can be manufactured. Further, in the above embodiment, the black matrix 14
Although the colored layer 16 is formed after forming the colored layer 16, the formation order is not limited to this, and the black matrix 14 may be formed after the colored layer 16 is formed.

As the photosensitive substance that develops tackiness upon exposure to light, the following 1,4-dihydropyridine compounds can be used. 1,4-dihydropyridine compound: 2,6-dimethyl-4-(2'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid dimethyl ester; 2,6-dimethyl-4-(2'- nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid diethyl ester; 2,6-dimethyl-4-(2'
-nitro-4',5'-dimethoxyphenyl)-1,4
-dihydropyridine-3,5-dicarboxylic acid diethyl ester; 2,6-dimethyl-4-(2'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid diisopropyl ester; 2,6-dimethyl-4 -(2'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid di(β-ethoxyethyl) ester; 2,6-dimethyl-4-(2'-nitrophenyl)-1,4- Dihydropyridine-3,5-dicarboxylic acid 3-methyl-5-ethyl ester; 2,
6-dimethyl-4-(2'-nitrophenyl)-1,4
-dihydropyridine-3,5-dicarboxylic acid 3-isopropyl-5-methyl ester; 2,6-dimethyl-
4-(2'-nitrophenyl)-3-aceto-1,4-
Dihydropyridine-5-carboxylic acid ethyl ester;
2,6-dimethyl-4-(2'-nitrophenyl)-
3,5-diaceto-1,4-dihydropyridine and 2
,6-dimethyl-4-(2'-nitrophenyl)-3,
5-dicyano-1,4-dihydropyridine.

Such 1,4-dihydropyridine compounds may contain, for example, 1 mol of an aliphatic or aromatic aldehyde,
It can be produced from 1 mol of ammonia and 2 mol of β-ketocarboxylic acid ester, β-ketocarboxylic acid nitrile or β-diketone according to the method of Hantzsch synthesis. In addition to the 1,4-dihydropyridine compounds shown above, various photosensitive diazonium salts such as DDMA shown by the following chemical formula can be used as the photosensitive substance.

[0019]

[Chemical formula 1]

However, when a photosensitive diazonium salt is used as the photosensitive substance, the uniform distribution of the concealing powder substance or the colored powder substance in the exposed area cannot be achieved if the exposure and powder substance scattering are performed in the presence of a fixed amount of moisture. This is only possible if This requires expensive equipment to determine and control indoor humidity and indoor air exposure time.

The above photosensitive materials may be used alone to form the photosensitive layer 13, or may be used in combination with a binder. The mixing ratio with the binder is preferably about 0.2 to 9 parts by weight per 1 part by weight of the binder. Binders used include copolymers of polyacrylic esters and/or polymethacrylic esters, acrylic acid and/or methacrylic acid or other acrylic monomers and/or vinyl monomers;
Copolymers of maleic anhydride, maleic acid and/or its styrene, or di- or semi-esters of other vinyl monomers; polyvinyl chloride, its chlorinated products, polyvinylidene chloride, chlorinated polyethylene, etc. Chlorine-containing vinyl polymer or copolymer;
Styrene copolymers with polystyrene and maleic acid, etc., ethylene copolymers with polyethylene and maleic acid, etc.; Synthetic rubbers based on butadiene, chloroprene, etc. and their copolymers with styrene, acrylonitrile, etc.; High molecular weight polyethylene oxide Or a polyether such as polyepichlorohydrin.

[0022] Furthermore, the photosensitive substance may contain a sensitizer, a stabilizer, and the like. In order to apply the photosensitive material as described above onto the transparent substrate 12, a known method such as a spin coating method can be used. Further, examples of the light source used for exposing the photosensitive layer 13 include an ultra-high pressure mercury lamp, a xenon lamp, a fluorescent lamp, and the like. The irradiance during exposure is 50
It is preferably about 300 mJ/cm2.

The concealing powder material and the colored powder material include titanium oxide (TiO2), SiO2, glass powder, carbon black, graphite, copper-phthalocyanines,
Azo dyes, metal powders such as aluminum, copper, iron, etc. or metal oxides are mixed with a binder to an average particle size of 30 μm.
Hereinafter, preferably fine particles of 3 μm or less can be used.

As the binder, polystyrene homopolymer, hydrogenated styrene resin, styrene-isobutylene copolymer, styrene-butadiene copolymer, ABS (
Acrylonitrile-butadiene-styrene terpolymer), ASA or AAS (acrylonitrile-styrene-acrylic acid ester terpolymer), AS or SA
N (styrene/acrylonitrile copolymer), AAS (
Acrylonitrile/acrylic rubber/styrene terpolymer), ACS (acrylonitrile/chlorinated polyethylene/styrene terpolymer), AES (acrylonitrile/EVA/styrene terpolymer), styrene/P-chlorostyrene copolymer Coalescence, styrene-propylene copolymer,
Styrene/butadiene crosslinked polymer, styrene/allyl alcohol copolymer, styrene/butadiene rubber emulsion, styrene/maleic acid ester copolymer, styrene/isobutylene copolymer (self-crosslinked), styrene/maleic anhydride copolymer, Polystyrene resins such as styrene/3-N,N diethylaminopropyl acrylate copolymer; polymethyl methacrylate, ethyl methacrylate, n-butyl methacrylate, glycidyl methacrylate, fluorine-containing acrylate, methylene methacrylate/butyl methacrylate Acrylic resins such as acrylate copolymers, ethyl acrylate/acrylic acid copolymers; styrene/acrylic copolymers, styrene/diethylamino/ethyl methacrylate copolymers,
Styrene-butadiene-acrylic ester copolymer,
Styrene/butadiene copolymer, styrene/butadiene/chlorinated paraffin copolymer, styrene/methyl methacrylate copolymer, styrene/methyl methacrylate copolymer/styrene butyl methacrylate blend, styrene/n-butyl methacrylate , styrene/diethylamino/ethyl methacrylate, styrene/methyl methacrylate/n-butyl acrylate (
75:5:20), styrene/methyl methacrylate/butyl acrylate-N-(ethoxymethyl)acrylamide, styrene/glycidyl methacrylate, styrene/dimethylamino/ethyl methacrylate, styrene/butadiene/dimethyl/aminoethyl methacrylate ( 60:26:4), styrene/acrylic ester/maleic ester (terpolymer), styrene/methyl methacrylate/2-ethylhexyl acrylate copolymer, styrene/n-butyl acrylate/ethyl glycol meth Acrylate, styrene/n-butyl methacrylate/acrylic acid copolymer (59:40
:1), Styrene/n-butyl methacrylate/maleic anhydride resin, styrene/butyl acrylate/isobutyl maleic acid half ester/divinylbenzene copolymer, styrene/n-butyl acrylate-4-hexafluorobutyl methacrylate copolymer Coalescence, styrene-butadiene-acrylate copolymer (59:36:5
) can be used. Additionally, additives such as wetting agents and antistatic agents may be added to the binder. Incidentally, as the concealing powder substance, powder of metal, carbon black, graphite, etc. may be used directly without using a binder. In this case, the metal powder has an average particle size of 1μ
The carbon black powder and graphite powder preferably have an average particle diameter of 3 μm or less.

[0025] The deposition of the concealing powder substance and each colored powder substance on the exposed area may be performed only once as described above, or may be repeated multiple times. Further, after forming the black matrix 14 and the colored layer 16, heat treatment (100 to 500°C, preferably 200 to 300°C) is performed.
°C) may be applied. Through such heat treatment, the photosensitive substance of the photosensitive layer 13 is sublimed and removed, improving the adhesion between the transparent substrate 12 and the black matrix 14 and the colored layer 16, and smoothing the surfaces of the black matrix 14 and the colored layer 16. Improves sex. In particular, transparent substrate 1
When the photosensitive layer 13 is provided on the entire surface of the filter 2 to form the black matrix 14 and the colored layer 16, the photosensitive layer 13 is also present at the peripheral edge of the resulting color filter, and peeling occurs from this area. There is a fear. In such a case, it is extremely effective to sublimate and remove the photosensitive substance of the photosensitive layer 13 by the heat treatment as described above.

A protective layer 18 is provided to cover the black matrix 14 and colored layer 16 of the color filter 10.
smooths the surface of the color filter 10, improves reliability,
It is intended to prevent contamination of the liquid crystal layer 40, etc., and can be formed using a transparent resin for acrylic resin, epoxy resin, polyimide resin, or a transparent inorganic compound such as silicon dioxide. . The thickness of the protective layer is preferably about 0.5 to 50 μm.

As the transparent common electrode 19, an indium tin oxide (ITO) film can be used. The ITO film can be formed by a known method such as a vapor deposition method or a sputtering method, and the thickness is preferably about 200 to 2000 Å. Next, the present invention will be explained in more detail by showing experimental examples. (Experimental example 1) First, 500 ml of methyl ethyl ketone solvent
50 g each of DHP-E and DHP-M manufactured by DuPont were dissolved in the solution to prepare a photosensitive material that becomes sticky when exposed to light. Using Corning 7059 glass (thickness = 1.1 mm) as a transparent substrate, a photosensitive substance was applied onto the transparent substrate by a spin coating method (rotation speed = 450 rpm) to form a photosensitive layer. (thickness = 1.5
μm) was formed.

Next, the photosensitive layer was exposed to ultraviolet light through a black matrix photomask. The light source for exposure is an ultra-high pressure mercury lamp, and the irradiation amount is 365 nm.
It was set to 200 mJ/cm2 at the wavelength of . It was confirmed that by such exposure to ultraviolet rays, adhesiveness was developed in the area of the photosensitive layer that was irradiated with ultraviolet rays. Next, black toner (manufactured by Tomoekawa Paper Manufacturing Co., Ltd., average particle size = 5 μm) was sprinkled over the entire surface of the photosensitive layer, and then the black toner was blown away with compressed air. As a result, the black toner adhered only to the area where tackiness was developed due to the above-mentioned ultraviolet exposure, and a black matrix pattern was formed. Note that the black toner blown away (removed) by compressed air in this step can be collected and used again. The resolution at this time was 10 μm for lines and spaces.

Next, the photosensitive layer to which the black toner was attached was exposed to ultraviolet light at predetermined positions through a photomask for a red pattern. The ultraviolet exposure conditions were the same as those for the above exposure. Then, as in the case of the black toner, a red pattern was formed using a red toner (manufactured by Tomoekawa Paper Manufacturing Co., Ltd., average particle size = 8 μm). Next, the photosensitive layer to which the black toner and red toner are attached is exposed to ultraviolet light at predetermined positions through a photomask for the green pattern in the same manner as the red pattern, and the green toner (Tomoekawa Paper Mills) Co., Ltd., average particle size = 5 μm) to form a green pattern.

Furthermore, the photosensitive layer to which the black toner, red toner, and green toner are attached is exposed to ultraviolet light at predetermined positions through a photomask for the blue pattern in the same manner as the red pattern, and the blue toner is (manufactured by Tomoekawa Paper Manufacturing Co., Ltd., average particle size = 5 μm) to form a blue pattern. As a result, red (R), green (G), blue (B)
A colored layer having a colored pattern was formed.

Next, a protective layer was formed to cover the colored layer. This protective layer was formed by spin coating using Optomer SS manufactured by Nippon Synthetic Rubber Co., Ltd., and had a thickness of about 25 μm. Furthermore, a transparent common electrode (ITO) with a thickness of approximately 220 Å is deposited on this protective layer by sputtering.
A color filter was obtained by forming a film). (Experimental Example 2) After forming a black matrix and a colored layer having a colored pattern of red (R), green (G), and blue (B) in the same manner as in Experimental Example 1, heat treatment was performed at 270°C for 30 minutes. Thereafter, a protective layer and a transparent common electrode (ITO film) were formed in the same manner as in Experimental Example 1 to obtain a color filter. In this color filter, the photosensitive substance was removed by sublimation, and the surface smoothness of the black matrix and colored layer was improved compared to the color filter obtained in Experimental Example 1 above.

[0032]

As described in detail above, according to the present invention, a photosensitive material having a black matrix pattern is coated on a transparent substrate to form a photosensitive layer. The photosensitive layer is exposed to light through a mask, a concealing powder substance is attached to the exposed area to form a black matrix, and the photosensitive layer is exposed to light through a photomask having a predetermined pattern, and a colored powder substance is attached to the exposed area. By repeating the process of depositing and forming a colored pattern for the required number of colors to form a colored layer, it is extremely easy to form a fine pattern in a color filter.
The process is simplified and manufacturing costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of an active matrix liquid crystal display using a color filter manufactured according to the present invention.

FIG. 2 is a schematic cross-sectional view of the liquid crystal display shown in FIG. 1;

FIG. 3 is an enlarged partial cross-sectional view of a color filter used in the liquid crystal display shown in FIG. 1;

FIG. 4 is a process diagram for explaining a method for manufacturing a color filter according to the present invention.

FIG. 5 is a process diagram for explaining a method for manufacturing a color filter according to the present invention.

[Explanation of symbols]

10 Color filter 12 Transparent substrate 13 Photosensitive layer 14 Black Matrix 16 Colored layer

Claims (3)

[Claims] 1. A method for producing a color filter comprising a colored layer having a colored pattern of a plurality of colors and a black matrix, the method comprising forming a photosensitive layer by coating a transparent substrate with a photosensitive substance that develops tackiness upon exposure to light. After that, the photosensitive layer is exposed to light through a photomask having a pattern for a black matrix, a concealing powder substance is attached to the exposed area to form a black matrix, and the photosensitive layer is exposed to light through a photomask having a predetermined pattern. A method for manufacturing a color filter, which comprises forming a colored layer by repeating the steps of exposing the layer to light and attaching a colored powder substance to the exposed portion to form a colored pattern for the required number of colors. 2. The method for producing a color filter according to claim 1, wherein a heat treatment is performed after forming the black matrix and the colored layer. 3. Claim 1 or 2, wherein the photosensitive substance is a 1,4-dihydropyridine compound.
A method for manufacturing the color filter described.