JP3287635B2 - Manufacturing method of color filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a color filter, and more particularly to a method for manufacturing a color filter used for a liquid crystal display or the like.

[0002]

2. Description of the Related Art For example, in a liquid crystal display (LCD), a color filter is used in both an active matrix system and a simple matrix system in order to meet the recent demand for colorization. For example, in an active matrix type liquid crystal display using a thin film transistor (TFT), three primary colors of red (R), green (G), and blue (B) are used as color filters, and each pixel of R, G, and B is used. The liquid crystal operates as a shutter by turning on and off the electrodes corresponding to the above, and light is transmitted through each of the R, G, and B pixels to perform color display. Color mixing is visually performed on the retina by the principle of additive color mixing in which liquid crystal shutters corresponding to pixels of two or more colors are opened to mix colors and make the colors look different.

[0003] The above-mentioned color filters include the following depending on the forming method, and the required characteristics include pattern resolution, spectral property, heat resistance, weather resistance, chemical resistance, and low manufacturing cost. And that there are no defects and high workability. (A) Dyeing method color filter To form a color filter by a dyeing method, a coating solution obtained by adding a photosensitive agent such as dichromate to a hydrophilic resin such as gelatin, casein or polyvinyl alcohol is applied by a spin coating method or the like. After coating to a thickness of about 0.4 to 2 μm on the surface of the transparent glass substrate, exposure and development are performed through a mask having a predetermined shape to form a layer to be dyed, and the layer to be dyed is coated with an acid dye or a reactive dye. Dyeing is performed to form a first colored layer.
Next, after forming an anti-dyeing layer of acrylic, urethane, epoxy or the like for preventing double dyeing on the first-colored layer, the second and subsequent colored layers are formed in the same process. G, B
A color filter having each of the colored layers can be formed. (B) Dispersion method color filter In order to form a color filter by the dispersion method, a photosensitive liquid in which a dye, an organic pigment, an inorganic pigment, or the like is dispersed as a coloring agent in a transparent photosensitive resin is coated on a transparent substrate. A resin layer is formed. Next, this photosensitive resin layer is exposed and developed through a mask having a predetermined shape to form a first color layer, and similarly, a second and subsequent color layers are formed to form R, G, and B color layers. A color filter having each of the colored layers can be formed.

[0004]

However, in the above-mentioned dyeing method, it is necessary to perform a photolithography process every time the color is changed, and it is necessary to form an anti-dyeing layer for preventing double dyeing. In addition, the process becomes complicated and there is a problem in the production cost. In addition, since a dye is used as a coloring agent, there is a problem that heat resistance, weather resistance, chemical resistance and the like are inferior.

[0005] In the dispersion method, a color filter having a fine pattern having excellent heat resistance, weather resistance, chemical resistance and the like can be manufactured. However, similar to the dyeing method, a photolithography step is performed every time the color is changed. It is necessary to perform the treatment, and the process becomes complicated, and there is a problem in the production cost.

As a method for solving such a problem, a method for producing a color filter by electrodeposition has been developed.
In the electrodeposition method, for example, a transparent conductive film formed on a substrate is patterned to form a transparent electrode, and a voltage is selectively applied only to a portion of the patterned transparent electrode where a colored layer of the same color is formed. Then, electrodeposition is performed in a colored electrodeposition bath to form a colored layer of the first color. Next, a voltage is selectively applied only to a portion where a colored layer of another color is to be formed.
By forming a colored layer after the color, a color filter having R, G, and B colored layers can be formed.

However, in the above-described production of a color filter by electrodeposition, if a black matrix is formed with chromium metal or the like before the formation of the colored layer, the colored layer is also formed on the black matrix when the colored layer is formed. There was a problem. This problem is a problem that occurs when a black matrix is formed using a material in which a black pigment is dispersed, when a conductive material such as carbon black is used as the black pigment.

Further, a method of forming a black matrix by forming a colored layer composed of R, G and B, applying a photoresist in which a black pigment is dispersed, and exposing and developing the same has been proposed. There is a reciprocal relation to utilizing a photoreaction for the material, and as a result, it has been difficult to obtain a sufficient optical density as a color filter.

The present invention has been made in view of the above circumstances, and provides a method of manufacturing a color filter capable of obtaining a color filter having a black matrix having a sufficient optical density with high accuracy and efficiency. The purpose is to provide.

[0010]

According to the present invention, a transparent electrode having a predetermined pattern is formed on a transparent substrate, and a plurality of electrodeposition coloring patterns are formed on the transparent electrode. A first step of forming a colored layer having a predetermined number of colors by sequentially forming a black matrix film on the transparent substrate on which the colored layer is not formed;
A second step of forming a relief containing a hydrophilic resin, an inorganic substance, and a metal compound serving as a catalyst for electroless plating via a photomask; and contacting the relief with an electroless plating solution to form a relief in the relief. Third to deposit metal and form black matrix as black relief
And a step of:

[0011]

A plurality of electrodeposited colored patterns are sequentially formed by electrodeposition on the surface of a transparent electrode having a predetermined pattern formed on a transparent substrate to form a desired colored layer, and thereafter, a colored layer is not formed on the transparent substrate. A relief containing a hydrophilic resin and a metal compound serving as a catalyst for electroless plating is formed in a portion, and the relief is brought into contact with the electroless plating solution to deposit metal therein to form a black relief (black matrix). You. As a result, a fine pattern with higher precision is formed than in the conventional method, and a color filter having a black matrix with a sufficient optical density can be easily and efficiently manufactured.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a process chart for explaining a method of manufacturing a color filter according to the present invention. 1, first, a transparent electrode 3 is formed on a transparent substrate 2 using a transparent conductive material such as indium tin oxide (ITO) (FIG. 1).
(A)). The transparent electrode 3 is formed in a pattern corresponding to the colored layers 4R, 4G, 4B formed in a step described later. Such a transparent electrode 3 is formed, for example, by forming a transparent conductive material such as indium tin oxide (ITO) on the transparent substrate 2 by sputtering or the like (with a thickness of 200 to 200 nm).
About 2000 °) and then etching, or exposing and developing a photosensitive resist applied on the transparent substrate 2 through a photomask of a predetermined pattern, and applying a transparent conductive material on the exposed transparent substrate 2. Such as a method of forming a film,
It can be performed according to a known method.

Then, the transparent substrate 2 is immersed in an electrodeposition bath in which a red pigment is dispersed, and a DC voltage is selectively applied only to the transparent electrode 3 of the transparent electrodes 3 on which the red colored layer 4R is formed. Then, a red electrodeposition material is deposited, washed sufficiently with water, and dried to form a pinhole-free colored layer 4R (FIG. 1B).

Similarly, a green colored layer 4G and a blue colored layer 4B are formed on the transparent electrode 3 (FIG. 1C). Next, a photosensitive resist containing a hydrophilic resin is applied to the entire surface of the transparent substrate 2 to form a photosensitive resist layer 5, and the photosensitive resist layer 5 is exposed through a black matrix photomask 11 ( FIG. 1 (D)). Then, the exposed photosensitive resist layer 5 is developed to form a relief having a pattern for a black matrix, and the transparent substrate 2 is subjected to a heat treatment (100 to 200 ° C., 5 to 30 minutes). An aqueous solution of a metal compound serving as a catalyst for electroless plating is applied and washed with water to form a catalyst-containing relief 6 (FIG. 1E). The catalyst-containing relief 6 is brought into contact with an electroless plating solution to form a black relief and a black matrix 7. Further, a protective layer 8 and a transparent common electrode 9 are provided so as to cover the colored layers 4R, 4G, 4B and the black matrix 7 formed as described above, thereby forming a color filter 1 (FIG. 1F).

As the transparent substrate 2 of the color filter 1,
A rigid material having no flexibility such as quartz glass, Pyrex glass, or a synthetic quartz plate, or a flexible material having flexibility such as a transparent resin film or an optical resin plate can be used. Among them, Corning 7059 glass is a material having a small coefficient of thermal expansion, is excellent in dimensional stability and workability in high-temperature heat treatment, and is an alkali-free glass containing no alkali component in the glass.
It is suitable for a color filter for an active matrix type LCD.

The electrodeposition material used in the above manufacturing process is generally made of an organic material (polymer material), and its original form is well known as an electrodeposition coating method. In electrodeposition coating, there are cation electrodeposition and anion electrodeposition due to electrochemical reaction with the main electrode. This is categorized according to whether the electrodeposited material exists as a cation or behaves as an anion. Examples of the organic polymer substance used for the electrodeposition include various organic polymer substances such as natural oils and fats, synthetic oils and fats, alkyd resins, polyester resins, acrylic resins, and epoxy resins.

As the anion type, maleated oil and polybutadiene resin have been known for a long time, and the hardening of the electrodeposited substance is based on an oxidative polymerization reaction. The cationic type has many epoxy resin types and can be used alone or modified. Other,
A so-called polyamino resin system such as a melamine resin system or an acrylic resin system is often used, and a strong colored layer can be formed by thermosetting, light curing, or the like.

In the electrodeposition of a liquid crystal color filter, finely pulverized pigments and dyes are dispersed in an anion-type or cation-type electrodeposition bath, and co-deposited with the ionic polymer material on the conductive portion.

The photosensitive resist used in the present invention includes, for example, a diazonium compound having a diazo group as a photocurable photosensitive group and a diazo resin which is a reaction product of paraformaldehyde, an azide compound having an azide group, and polyvinyl alcohol. Examples thereof include a resin having a photosensitive group such as a cinnamic acid condensed resin obtained by condensing cinnamic acid, a resin using a stilbazolium salt, and ammonium bichromate. It is needless to say that the photosensitive group is not limited to the photocurable photosensitive group described above.

Examples of the hydrophilic resin contained in the photosensitive resist include natural proteins such as gelatin, casein, glue, ovalbumin, carboxymethylcellulose, polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, and anhydride. And maleic acid copolymers. Further, an inorganic substance such as ceramics or porous alumina may be added to the photosensitive resist. Such a hydrophilic resin or inorganic substance is preferably contained in the photosensitive resist at about 10% by weight. As described above, since the photosensitive resist contains the hydrophilic resin, when the catalyst-containing relief 6 comes into contact with the electroless plating solution as described above, the electroless plating solution permeates the catalyst-containing relief 6. Thus, the metal particles are uniformly deposited in the catalyst-containing relief 6. Therefore, the formed black matrix 7 has sufficient blackness and low reflectance.
The problem of reflection by the metal layer in the conventional chromium thin film formation can be solved.

The metal compound used as a catalyst for electroless plating used in the present invention includes, for example, chlorides such as palladium, gold, silver, platinum and copper, water-soluble salts such as nitrates, and complex compounds. The activator solution for electroless plating that has been used can be used as it is.

The content of the metal contained in the catalyst-containing relief 6 and serving as a catalyst for electroless plating is from 0.0001 to 0.0001.
It is preferably about 0.001% by weight. The electroless plating solution used in the present invention is, for example, a reducing agent such as hypophosphorous acid, sodium hypophosphite, sodium borohydride, N-dimethylamineborazane, a borazane derivative, hydrazine, formalin, and, for example, nickel, cobalt , Iron, copper, water-soluble reducible heavy metal salts such as chromium and the like, caustic soda to improve plating rate, reduction efficiency, etc., basic compounds such as ammonium hydroxide, and inorganic acids, pH adjusters such as organic acids, Buffering agents such as sodium citrate, sodium acetate, and other oxycarboxylic acids, boric acid, carbonic acid, organic acids, alkali salts of inorganic acids, and complexing agents for the purpose of stabilizing heavy metal ions, as well as reaction promotion An electroless plating solution having an agent, a stabilizer, a surfactant and the like is used.

The protective layer 8 is used to smooth the surface of the color filter 1, improve the reliability, and improve the liquid crystal display (LC).
The purpose of the present invention is to prevent contamination of the liquid crystal layer when used in D), for example, acrylic resin, epoxy resin,
It can be formed using a transparent resin such as a polyimide resin or a transparent inorganic compound such as silicon dioxide.
The thickness of such a protective layer is preferably about 0.5 to 50 μm.

Further, as the transparent common electrode 9, an indium tin oxide (ITO) film or the like can be used. IT
The O film can be formed by a known method such as an evaporation method and a sputtering method, and the thickness is preferably about 200 to 2000 °.

Next, the present invention will be described in more detail with reference to experimental examples. (Experimental example) Indium tin oxide (IT
O) was formed by sputtering to form an ITO layer, and then the ITO layer was etched to form a transparent electrode having a positive pattern of a colored layer.

On the other hand, a red pigment (naphthol red) was added to an anion-type electrodeposition material (Oligo ED manufactured by Nippon Petrochemical Co., Ltd.) diluted with pure water so that the residual solid content was 13.5% by weight. An electrodeposition solution for a red colored layer was prepared by adding 5% by weight. Then, in this electrodeposition solution, the substrate is immersed in such a manner that the transparent electrode is used as an anode and the platinum electrode is used as a cathode, and the distance between the electrodes is 30 mm. Was applied for 60 seconds to perform electrodeposition. Next, the substrate taken out of the electrodeposition solution was sufficiently washed with water, and then dried at 80 ° C. for 10 minutes to form a red colored layer having good transparency.

Next, an electrodeposition solution for a green colored layer was prepared in the same manner as the above-mentioned electrodeposition solution for a red colored layer except that a green pigment (phthalocyanine green) was used instead of the red pigment.
Then, using the electrodeposition liquid for a green colored layer, electrodeposition was performed under the same conditions as in the formation of the red colored layer. Next, after sufficiently washing the substrate taken out of the electrodeposition solution at 80 ° C., 10 ° C.
After drying for minutes, a green colored layer having good transparency was formed.

Further, an electrodeposition solution for a blue colored layer was prepared in the same manner as the above-mentioned electrodeposition solution for a red colored layer except that a blue pigment (copper phthalocyanine blue) was used instead of the red pigment. Then, using the electrodeposition liquid for a blue colored layer, electrodeposition was performed under the same conditions as in the formation of the red colored layer. Next, after sufficiently washing the substrate taken out of the electrodeposition solution at 80 ° C.
Drying was performed for 10 minutes to form a blue colored layer having good transparency.

Next, a photosensitive resist having the following composition is applied on the transparent substrate having the colored layer formed thereon by a spin coating method (rotation speed = 1500 rpm), and then dried at 70 ° C. for 5 minutes. Thus, a photosensitive resist layer (thickness = 1 μm) was formed.

Composition of photosensitive resist ・ Polyvinyl alcohol 10% aqueous solution (Nippon Gohsei Chemical Gosenal T-330) 20 parts by weight ・ Diazo resin 10% aqueous solution (Shinko Giken D-011) 20 parts by weight ・ Water 15 Next, the photosensitive resist layer was exposed to light via a black matrix photomask (line width = 50 μm). The light source for the exposure is an ultra-high pressure mercury lamp 2 kw,
Irradiated for seconds. Thereafter, spray development was performed using water at normal temperature and air drying was performed to form a relief for a black matrix between the colored layers.

Next, the transparent substrate is subjected to a heat treatment at 150 ° C. for 30 minutes, and thereafter, an aqueous solution of palladium chloride (Nippon Kanigen Red Schumer) is spray-applied on the relief, washed with water and drained. It was a catalyst-containing relief.

Thereafter, the transparent substrate is immersed in a nickel plating solution containing a boron-based reducing agent at 30 ° C. (nickel plating solution Top Chemialloy B-1 manufactured by Okuno Pharmaceutical Co., Ltd.) for 5 minutes, washed with water and dried to give a black relief (black matrix). Was formed to obtain a color filter.

When the optical density D and the reflectance R of this black matrix were measured, D ≧ 3.0 and R ≦ 5%
In addition, the adhesion between the black matrix and the glass substrate was good with no lifting, peeling, or the like. This indicates that the black matrix formed according to the present invention has a sufficient optical density and a low reflectance as a black matrix for a color filter.

Further, a liquid crystal display (LCD) was prepared using the obtained color filters, and a color image was displayed. As a result, a good color image without color shift or bleeding was displayed.

[0035]

As described in detail above, according to the present invention, a colored layer is formed by electrodeposition, so that a highly accurate colored layer can be formed. Since a metal is deposited in the catalyst-containing relief by plating to form a black matrix, a metal material can be used for the light-shielding layer, and a black matrix having a large optical density and a low reflectance can be formed.

[Brief description of the drawings]

FIG. 1 is a process chart for explaining a method of manufacturing a color filter according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Color filter 2 ... Transparent substrate 3 ... Transparent electrode 4R, 4G, 4B ... Coloring layer 5 ... Photosensitive resist layer 6 ... Catalyst containing relief 7 ... Black matrix

Claims (1)

(57) [Claims] 1. A method for forming a colored layer having a predetermined number of colors by forming a transparent electrode having a predetermined pattern on a transparent substrate and sequentially forming a plurality of electrodeposition coloring patterns on the transparent electrode. Step 1 and forming a relief containing a hydrophilic resin, an inorganic substance, and a metal compound serving as a catalyst for electroless plating on the transparent substrate on which the colored layer is not formed, through a photomask for a black matrix. A second step of forming a black matrix as a black relief by depositing a metal in the relief by bringing the relief into contact with an electroless plating solution to form a black matrix. Production method.