JPH05288923A - Color filter - Google Patents

Abstract

PURPOSE:To provide a highly precise color filter used for the flat display of a liquid crystal display, etc., the imager of a CCD, etc., or a color sensor, etc. CONSTITUTION:The color filter has a transparent substrate 12 and a color layer 16, which consists of colored patterns 16R, 16G, and 16B of plural colors formed by exposing a photosensitive layer, formed by coating the transparent substrate 12 with a photosensitive material developing stickiness by exposure, through a photomask having a specific pattern and sticking a colored powder material on the exposed part A transparent conductive film 19 is formed on this colored layer 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter,
In particular, the present invention relates to a color filter used for a flat display such as a liquid crystal display, an imager such as a CCD, or a color sensor.

[0002]

2. Description of the Related Art For example, an image pickup tube of a color video camera is equipped with a color filter having fine stripes of a plurality of colors formed on a transparent substrate.

Also in liquid crystal displays (LCDs), color filters are used in both the active matrix system and the simple matrix system in order to meet recent demands for colorization. For example, in an active matrix type liquid crystal display using a thin film transistor (TFT), a color filter includes a colored layer formed of three primary colors of red (R), green (G) and blue (B) on a transparent substrate. , R,
The liquid crystal operates as a shutter by turning on and off the electrodes corresponding to the respective pixels of G and B, and light is transmitted through the respective pixels of R, G and B to perform color display. Then, color mixing is visually performed on the retina based on the principle of additive color mixing in which liquid crystal shutters corresponding to pixels of two or more colors are opened and colors are mixed to make another color appear.

The colored layer of the color filter used as described above has hitherto been formed by a method such as a dyeing method or a dispersion method. Here, the formation of the colored layer of the color filter by the dyeing method has been performed as follows, for example.

That is, a coating solution prepared by adding a photosensitizer such as dichromate to a hydrophilic resin such as gelatin, casein or polyvinyl alcohol is coated on a transparent glass substrate by a spin coating method or the like, and then a predetermined pattern is formed. The mask is used for exposure and development, and then dyed with a dye to form a first colored layer. After that, a dye-proof layer is provided on the first colored layer to prevent double dyeing, and then the second colored layer and the third colored layer are respectively formed in the same manner as the formation of the first colored layer. As a result, R, G,
It is possible to obtain a color filter provided with each colored layer of B.

Further, the formation of the colored layer of the color filter using the dispersion method has been performed as follows, for example. That is, a photosensitive liquid in which a colorant such as an organic pigment or an inorganic pigment is dispersed in a transparent photosensitive resin is applied on 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 color layer and a third color layer are formed to obtain a color filter having R, G, and B color layers.

Further, in the active matrix system, the transparent conductive film which is a common electrode is provided on the colored layer of the color filter, and in the simple matrix system the transparent conductive film is provided so as to form an electrode array on the colored layer.

[0008]

However, although the color filter formed by the dyeing method has a rich color tone and is excellent in resolution, it is dye-proofed so that the already colored portion is not dyed twice during dyeing. There is a problem that the process is complicated and the manufacturing cost is high because it is necessary to take measures. Further, since a dye is used as the colorant, there is a problem that heat resistance, chemical resistance, light resistance and the like are poor.

Further, the color filter formed by the dispersion method can form a fine pattern having high heat resistance and light resistance, but on the other hand, it is necessary to perform a photolithography process every time the color is changed. There is a problem that it is complicated and it is difficult to reduce the manufacturing cost.

From such a background, there has been proposed a color filter manufactured by a printing method which enables cost reduction and mass production at the same time and also enables a large screen. However, in the printing method, the print shape is deteriorated due to thickening or thinning of pixels, the occurrence of pinholes, etc., and the thickness of fine lines cannot be sufficiently obtained, so that the obtained color filter has a problem in reproducibility of a fine pattern. Further, in a color filter provided with a high-quality black matrix, there is a problem that it is necessary to form the black matrix by a chrome vapor deposition method or the like, and the manufacturing cost increases.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a highly accurate color filter used for a flat display such as a liquid crystal display, an imager such as a CCD, or a color sensor. To aim.

[0012]

In order to achieve such an object, the present invention provides a transparent substrate and a photosensitive material formed by applying a photosensitive substance that exhibits adhesiveness upon exposure to the transparent substrate. A colored layer having a plurality of colored patterns formed by exposing the layer through a photomask having a predetermined pattern and depositing colored powder substances on the exposed portion; and a transparent conductive film laminated on the colored layer It was configured like this.

[0013]

The color filter has a plurality of colors formed by adhering the colored powder substance to the exposed portion where the photosensitive layer on the transparent substrate is exposed through a photomask having a predetermined pattern to exhibit adhesiveness. A colored layer having a colored pattern is provided, and a transparent conductive film is laminated on the colored layer. As a result, a color filter having a highly precise fine pattern can be obtained.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a schematic configuration of a color filter which is an embodiment of the present invention. In FIG. 1, a color filter 10 is a color filter for an active matrix system, and includes a transparent substrate 12 and this transparent substrate 12
The black matrix 14 formed above and the colored layer 1
6, a black matrix 14 and a protective layer 18 provided so as to cover the colored layer 16 and a transparent common electrode 19. The colored layer 16 is composed of a red pattern 16R, a green pattern 16G and a blue pattern 16B.

FIG. 2 is a perspective view showing an example of an active matrix type liquid crystal display (LCD) using the color filter of the present invention, and FIG. 3 is a schematic sectional view of the same. 2 and 3, the LCD 1
Makes the color filter 10 and the transparent glass substrate 20 face each other with a sealant 30 in between, and forms a liquid crystal layer 40 made of twisted nematic (TN) liquid crystal with a thickness of about 5 to 10 μm between them. The polarizing plates 50 and 51 are arranged outside the transparent glass substrate 20. The color filter 10 is arranged so that the transparent common electrode 19 is located on the liquid crystal layer 40 side.

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

The arrangement of the respective colored patterns of the colored layer 16 of the color filter 10 is a mosaic arrangement as shown in FIG. 2, but the arrangement of the colored patterns is not limited to this and is a triangular arrangement. Alternatively, a stripe arrangement or the like may be used.

In such an LCD 1, each of the colored patterns 16R, 16G and 16B constitutes a pixel, and the display electrode corresponding to each pixel is turned on and off in a state where the 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.

The transparent substrate 12 of the color filter 10 is a rigid material such as quartz glass, Pyrex glass, or synthetic quartz plate, or a transparent resin film.
A flexible material having flexibility such as an optical resin plate can be used. Of these, Corning 7
059 glass is a material with a small coefficient of thermal expansion, has excellent dimensional stability and workability in high-temperature heat treatment, and since it is an alkali-free glass that does not contain an alkali component in the glass, it is a color filter for LCDs using an active matrix method. Suitable for

Here, an example of forming the black matrix 14 and the coloring layer 16 in the color filter of the present invention will be described with reference to FIGS. 4 and 5. First, the transparent substrate 12
A photosensitive material is applied on top to form a photosensitive layer 13 having a thickness of about 0.5 to 5 μm (FIG. 4 (A)). Next, the photosensitive layer 13 is exposed through a photomask for a black matrix to cause the exposed portion 13a to exhibit tackiness (FIG. 4).
(B)). Then, the masking powder substance is sprayed on the photosensitive layer 13 (FIG. 4C), and the masking powder substance is attached to the exposed portion 13a and the excess masking powder substance is blown off to form the black matrix 14 ( Figure 4
(D)).

Next, the photosensitive layer 13 is exposed to light through a photomask for a red pattern so that the exposed portion 13b exhibits tackiness (FIG. 5 (A)). Then, a red powder substance is dispersed on the photosensitive layer 13 (FIG. 5B), and the red powder substance is adhered to the exposed portion 13b and the excess red powder substance is blown off to form a red pattern 16R ( FIG. 5C). Similarly, it is exposed through a photomask for a green pattern, a green powder substance is adhered to form a green pattern 16G (FIG. 5D), and it is exposed through a photomask for a blue pattern to obtain a blue powder. A blue pattern 16B is formed by depositing the substance (FIG. 5).
(E)). In this way, the colored layer 16 including the red, green, and blue colored patterns is formed.

Black matrix 1 as described above
4 and the colored layer 16 may be formed and then subjected to heat treatment. The heat treatment condition is usually 150 ° C. or higher, preferably 250 ° C. or higher. By such heat treatment, the photosensitive substance in the photosensitive layer 13 is removed by sublimation, and the concealing powder substance constituting the black matrix 14 and the coloring layer 1 are removed.
The colored powder substance constituting 6 is flattened, and the surface smoothness of the black matrix 14 and the colored layer 16 is improved.

The concealment powder substance and each colored powder substance may be adhered to the exposed portion only once as described above, or may be repeated a plurality of times. Further, in the above-described embodiment, the colored layer 16 is formed after the black matrix 14 is formed, but the formation order is not limited to this, and the black matrix 14 is formed after the colored layer 16 is formed. It may be one that is done. Also, a color filter without a black matrix may be used.

As the photosensitive substance which exhibits tackiness when exposed to light, a 1,4-dihydropyridine compound as shown below 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 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 are, for example, 1 mol of aliphatic or aromatic aldehydes,
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 Hantzsch synthesis method.

The above-mentioned photosensitive substances may be used alone to form the photosensitive layer 13, or may be used as a mixture with a binder. The mixing ratio with the binder is preferably about 0.2 to 9 parts by weight with respect to 1 part by weight of the binder. Binders used include polyacrylic acid esters and / or polymethacrylic acid esters, acrylic acid and / or methacrylic acid or copolymers of other acrylic monomers and / or vinyl monomers;
Copolymers of maleic anhydride, maleic acid and / or its styrene, or di- or semiesters of other vinyl monomers; polyvinyl chloride, its chlorinated products, polyvinylidene chloride, chlorinated polyethylene, etc. Chlorine-containing vinyl polymer or copolymer; styrene copolymer with polystyrene and maleic acid,
Ethylene copolymers with polyethylene and maleic acid, etc .; Synthetic rubbers based on butadiene, chloroprene, etc. and their copolymers with styrene, acrylonitrile, etc .; and high molecular weight polyethylene oxides or polyethers such as polyepichlorohydrin.

Further, the photosensitive material may contain a sensitizer, a stabilizer and the like. To apply the above-mentioned photosensitive substance on the transparent substrate 12, a known method such as a spin coating method can be used. The light source used for exposing the photosensitive layer 13 may be an ultra-high pressure mercury lamp, a xenon lamp, a fluorescent lamp or the like. Exposure dose is 50
It is preferably about 300 mJ / cm ² .

The concealing powder substance and the coloring powder substance include titanium oxide (TiO ₂ ), SiO ₂ , glass powder, carbon black, graphite, copper-phthalocyanines, azo dyes, metal powders such as aluminum, copper and iron or metal oxides. It is possible to use fine particles having a mean particle size of 30 μm or less, preferably 10 μm or less, using a binder. As the binder, the above-mentioned photosensitive layer 1
3 Binders for forming and publicly available materials can be used. Further, additives such as a wetting agent and an antistatic agent may be added to the binder.

A protective layer 18 provided so as to cover the black matrix 14 and the colored layer 16 of the color filter 10.
Can be formed of a transparent organic material or a transparent inorganic material.

Acrylic resins, epoxy resins and polyimide resins can be used as the transparent organic material. The protective layer 18 is formed of the above resin by a spinner coating method, a bar coating method, a flexographic printing method, a casting method (a method of pouring a molten resin on an object to be coated, and then extending it to a predetermined thickness with a roller). It can be performed using a coating method. The thickness of the protective layer 18 is 0.2 to
It is about 50 μm, preferably about 0.5 to 10 μm.

As the transparent inorganic material, any one of silicon dioxide (SiO ₂ ), zinc sulfide (ZnS), dizirconium trioxide (Zr ₂ O ₃ ), and the like, or a combination of two or more thereof may be mentioned. You can The formation of the protective layer 18 made of such a transparent inorganic material can be carried out by a known method such as a sputtering method, a vapor deposition method such as ion plating or ion assist. Also,
It can also be formed by a dipping method using an organosilicon compound. The thickness of the protective layer 18 is preferably about 20 to 2000Å.

By thus forming the protective layer 18, the color filter 10 is provided with excellent surface smoothness, heat resistance, light resistance or chemical resistance. As the transparent common electrode 19, a metal thin film of Au, Ag, Cu, Pt, Rh, etc. (however, the thickness is 50 Å or less), SnO ₂ , TiO _{2 is used} .
₂ , CdO, Cd ₂ SnO ₄ , In ₂ O ₃ , ZnO, S
An oxide semiconductor thin film such as nO ₂ : Sb or ITO (In ₂ O ₃ : Sn) can be used, but an ITO or ZnO film is preferable in terms of transmittance and resistance. The above-mentioned transparent common electrode can be formed by a known method such as a vapor deposition method such as ion plating or ion assist, or a sputtering method. The thickness of the transparent common electrode 19 is preferably about 200 to 2000Å.

FIG. 6 is a schematic sectional view showing another embodiment of the color filter of the present invention. In FIG. 6, the color filter 60 is a color filter for a simple matrix system, and covers the transparent substrate 62, the black matrix 64 formed on the transparent substrate 62, the coloring layer 66, the black matrix 64 and the coloring layer 66. The protective layer 68 and the transparent electrode 69 thus provided are provided. Transparent electrode 6
Reference numeral 9 forms a plurality of electrode rows that form scanning electrodes. Such a transparent electrode 69 can be formed by a known method such as etching after being formed in the same manner as the transparent common electrode 19 described above.

Next, the present invention will be described in more detail with reference to experimental examples. (Experimental example 1) First, in 2-butanone 200 cm ³ ,
6-dimethyl-4- (2'-nitrophenyl) -1,4
-7.5 g of dimethyl ester of dihydropyridine-3,5-dicarboxylic acid and 2,6-dimethyl-4- (2'-
Nitrophenyl) -1,4-dihydropyridine-3,5
-The diethyl ester of dicarboxylic acid 7.5g was melt | dissolved and the photosensitive material which expresses adhesiveness by exposure was prepared. Then, using Corning 7059 glass (thickness = 1.1 mm) as a transparent substrate, the above-mentioned photosensitive substance was applied by a spin coating method (rotation number = 500 rpm), and a photosensitive layer ( Thickness = 1.5 μm).

Next, the photosensitive layer was exposed to ultraviolet light through a black matrix photomask. Ultra-high pressure mercury lamp was used as the light source for exposure, and the irradiation amount was 365 nm.
Was set to 200 mJ / cm ² . It was confirmed that such an ultraviolet exposure exposed the adhesive to the region of the photosensitive layer that was exposed to the ultraviolet.

Next, black toner (MB-15 Black SHC-3 (sample) by Sekisui Plastics Co., Ltd., average particle diameter = 14.2 μm) was sprinkled on the entire surface of the photosensitive layer, and then,
The black toner was blown off by compressed air. As a result, the black toner was adhered only to the region where the tackiness was developed by the above-mentioned UV exposure, and a black matrix pattern was formed. The black toner blown off (removed) by the compressed air in this step could be collected and reused. The resolution at this time was 10 μm in line and space.

Next, the photosensitive layer having the black toner adhered thereto was exposed to ultraviolet light at a predetermined position through a photomask for a red pattern. The ultraviolet exposure conditions were the same as the above exposure. Then, as in the case of the black toner, a red pattern (MB-8 red (manufactured by Sekisui Plastics Co., Ltd., average particle size = 8.7 μm)) was used to form a red pattern.

Next, the photosensitive layer on which the black toner and the red toner are adhered is exposed to ultraviolet light at a predetermined position through a photomask for the green pattern in the same manner as the red pattern, and the green toner (water accumulation) is applied. MB- manufactured by Kasei Kogyo Co., Ltd.
A green pattern was formed using 8 Green HC (sample), average particle size = 8.1 μm).

Further, the photosensitive layer on which the black toner, the red toner and the green toner are attached is exposed to ultraviolet light at a predetermined position through a photomask for the blue pattern in the same manner as the red pattern, and the blue toner is exposed. (MB-8 Blue HC by Sekisui Plastics Co., Ltd. (sample), average particle size =
8.9 μm) was used to form a blue pattern. As a result, a colored layer having a colored pattern of red (R), green (G), and blue (B) was formed.

Next, a protective layer was formed so as to cover such a colored layer. The protective layer was formed by applying a coating solution for a protective layer having the following composition on the colored layer by spin coating, and then curing by ultraviolet exposure. The thickness of the protective layer is about 8μ
It was m.

(Protective Layer Coating Liquid) O-cresol novolac epoxy acrylate 35 parts by weight Cresol novolac epoxy resin 15 parts by weight Dipentaerythritol hexaacrylate 50 parts by weight Irgacure 907 (manufactured by Ciba Geigy) 2 parts by weight -UVE1014 (manufactured by General Electric Co.) 2 parts by weight-Ethyl cellosolve acetate 200 parts by weight Further, a transparent common electrode (ITO film) having a thickness of about 220 Å was formed on this protective layer by a sputtering method to obtain a color filter. (Experimental Example 2) In the same manner as in Experimental Example 1, a black matrix and a colored layer having a red (R), green (G), and blue (B) colored pattern were formed, and then heat treatment was performed at 270 ° C for 30 minutes. After that, 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. (Experimental Example 3) After forming a black matrix, a coloring layer and a protective layer in the same manner as in Experimental Example 1, a transparent electrode array as shown in FIG. 6 was formed to obtain a color filter. The transparent electrode array was formed by using ITO to have a thickness of about 220 .ANG., A line width of about 95 .mu.m, and a pitch of about 110 .mu.m.

[0042]

As described in detail above, in the color filter according to the present invention, the exposed portion where the photosensitive layer on the transparent substrate is exposed through a photomask having a predetermined pattern to exhibit tackiness is colored. It has a colored layer consisting of a colored pattern of a plurality of colors formed by adhering a powder substance, and a transparent conductive film is provided on this colored layer, so that the fine pattern accuracy is good and the surface is excellent. The effect of having smoothness is exhibited.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a color filter of the present invention.

FIG. 2 is a perspective view showing an example of an active matrix type liquid crystal display using a color filter of the present invention.

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

FIG. 4 is a process drawing for explaining the production of the color filter of the present invention.

FIG. 5 is a process drawing for explaining the production of the color filter of the present invention.

FIG. 6 is a schematic sectional view showing another embodiment of the color filter of the invention.

[Explanation of symbols]

 10, 60 ... Color filter 12, 62 ... Transparent substrate 13, 63 ... Photosensitive layer 14, 64 ... Black matrix 16, 66 ... Coloring layer 16R, 16G, 16B ... Coloring pattern 18, 68 ... Protective layer 19 ... Transparent common electrode 69 ... Transparent electrode

Claims (5)

[Claims] 1. A transparent substrate and a photosensitive layer formed by applying a photosensitive material that exhibits adhesiveness upon exposure onto the transparent substrate are exposed through a photomask having a predetermined pattern to the exposed portion. A color filter comprising: a colored layer having a colored pattern of a plurality of colors formed by adhering a colored powder substance, and a transparent conductive film laminated on the colored layer. 2. The color filter according to claim 1, wherein the transparent conductive film is laminated on the colored layer via a protective layer. 3. The color filter according to claim 1, wherein the transparent conductive film is one of an indium tin oxide film and a zinc oxide film. 4. The thickness of the transparent conductive film is 200 to 200.
The color filter according to claim 1, wherein the color filter is 0Å. 5. The black matrix formed by exposing the photosensitive layer through a photomask having a black matrix pattern and depositing a masking powder substance on the exposed portion. Color filters.