JPH09302500A - Color filter manufacturing method using anionic electrodeposition paint - Google Patents

Abstract

(57) Abstract: To provide a method for manufacturing a color filter that ensures a high light transmittance, improves a paint utilization rate, and can freely design the shape of a black matrix. SOLUTION: (1) a step of fully coating a positive photoresist on a transparent conductive substrate and then partially exposing the transparent conductive substrate through an exposure and development process; and (2) an anionic electrodeposition method. The step of selectively coating a portion of the conductive substrate exposed by the exposure and development process with a colored electrodeposition resin layer, and (3) exposing the remaining positive photoresist to full exposure. And (4) heating and drying the transparent electrode substrate to cure the electrodeposition resin layer,
(5) a step of removing the positive photoresist left by the alkaline developer, and (6) the step (1) to
A method of manufacturing a color filter using an anionic electrodeposition coating material, which comprises repeating (5) to prepare the remaining electrodeposition resin layers having different hues.

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 for a liquid crystal display, and more particularly to a method for manufacturing a color filter using an anionic electrodeposition coating material which employs an anionic electrodeposition method.

[0002]

2. Description of the Related Art A color filter belongs to an expensive component of a liquid crystal display, and its main causes are a complicated manufacturing process, a high raw material cost, and a high raw material utilization rate. It can be low. This is a difficult problem in the color filter film manufacturing method by the pigment dispersion method which is widely adopted at present.

As is well known, the electrodeposition method has a relatively low manufacturing cost, but the electrodeposition method in the prior art is
A phenomenon in which the material was poorly mixed was widely observed, and the pigment dispersion method could not be replaced. For example, when an anionic electrodeposition coating material and a positive photoresist are used to deposit the anionic electrodeposition coating material on the entire surface of ITO (Indium-Tin Oxide) glass, the anionic electrodeposition coating method according to the conventional technique is used. It was observed that the coating material was altered by the developer. Further, when the cationic electrodeposition paint and the positive photoresist were combined, the phenomenon that the ITO glass was blackened was observed.

In addition, when ITO is etched in advance to form a stripe shape and electrodeposition is performed by a method in which electrodes are connected in series, it is not easy to form a lattice pattern in a black matrix.

As a conventional method for producing a color filter film, a dyeing method, a printing method, a pigment dispersion method, an electrodeposition method and the like have been generally used.

The dyeing method is, for example, US Pat. No. 4,820,619 (Toshiba), and this method is one in which a color filter is manufactured by dyeing a resin using a dye. However, since the heat resistance of the dye was insufficient, the chromatic aberration of the color filter film was relatively large, and it was not adopted by liquid crystal display manufacturers.

Further, since most of the printing methods employ pigments as dyes, there has been no problem of insufficient heat resistance of dyes, but in general, printing accuracy of printing machines is insufficient, and the printing accuracy is 100 μm. Since it was difficult to achieve resolution, it did not meet the needs of the manufacturer.

Further, the pigment dispersion method is divided into two methods, that is, an etching method and a photo-soligraphy method, and the heat resistance of the colored paint of the etching method is good, but the manufacturing process is complicated and necessary. Due to the large amount of material, it has been used less recently. Further, the photo-soligraphy method is a method which is relatively widely used at present. For example, US Pat. No. 5,085,973 (Matsushita Electric Industrial Co., Ltd.) and Japanese Patent Laid-Open No. 2-208602 (topographic printing).
This is the case with the method disclosed in (1), and since the resolution of 10 μm or less was achieved by using the photolithography technology and the heat resistance of the color filter film was also good, many manufacturers adopted it. Since the spin coating method requires 90% or more of the color coating material to be discarded, the cost is extremely high compared to other methods. Also,
Attempts have been made to replace the spin coating method with a method that uses precision coating technology such as roller coating to save expensive color coating materials, but in that case flatness is not sufficient, so no practical example has yet been seen. .

Further, in the electrodeposition method, a patterned conductive layer (ITO with pattern) is formed according to the shape of the transparent conductive layer (ITO = indium tin oxide) serving as a substrate.
n) type and entire surface (without pattern) conductive layer (ITO
It can be divided into two types of a "without pattern" type. Patterned conductive layer type electrodeposition methods are among the earliest techniques and are described, for example, in US Pat. No. 4,812,38.
No. 7 (Shinto Paint), No. 5,206,750 (Stanley Electric), No. 4,617,094 and No. 4,781,444, and No. 4,999,094.
No. (Seiko Denshi Kogyo)
First, the ITO conductive layer is etched into a stripe pattern by photolithography, then conductive layers of the same hue are connected in series at the positions required for each hue, and paints of different hues are applied on the conductive layer by electrodeposition. Was to be coated. Since such a method has good heat resistance because the dye is a pigment and the ITO conductive layer is produced by the photo-soligraphy method, the resolution has reached the level of 10 μm or less. The paint utilization rate of the electrodeposition method could be 98% or more, and the cost was superior to the pigment dispersion method. However, in the patterned conductive layer type electrodeposition method, it is necessary to connect the conductive layers of pixels of the same hue in series, and the pixels are often arranged in a straight line, so that the pixel positions can be set freely like other methods. Could not be arranged. Moreover, since many of the pixels are linear, the number of manufacturing steps has to be increased more than a predetermined number of times in order to manufacture a lattice pattern having a black frame. For example, in Japanese Unexamined Patent Publication No. 61-203403 (Asahi Glass Co., Ltd.), since the number of photolithography steps is increased, the manufacturing cost is increased.

In the whole surface (no pattern) conductive layer type electrodeposition method, it is not necessary to etch the ITO pattern in advance. By this method, the entire surface of the ITO conductive layer is coated with photoresist, and the same hue is obtained by the photo-soligraphy method. The corresponding pixel conductive layer is developed, and the residual photoresist is used as an insulating layer, and then the color paint is coated on the exposed conductive layer by the electrodeposition method. By repeating this step, three types of red, green and blue can be obtained. Pixel was coated on a conductive glass. Pixels manufactured by such a method have the advantage of high paint utilization rate of the electrodeposition method, while the pattern and arrangement of the pixels can be freely designed, which is a drawback of the patterned conductive layer type electrodeposition method. Was able to be solved. However, there is a problem that is difficult to solve even in the electrodeposition method of the whole surface (without pattern) conductive layer type. Since the entire surface (without pattern) conductive layer ITO uses the photoresist as an insulating layer, the developer of the photoresist deteriorates the colored coating layer when the coating is performed using the anionic electrodeposition paint. In order to prevent the colored coating layer from being deteriorated, the curing temperature of the colored coating layer is 120 ° C.
The alkali resistance was improved by increasing the above. However, in general, a positive photoresist (quinonediazide type) is difficult to remove due to a thermal crosslinking reaction when it reaches 120 ° C. Therefore, in order to solve this problem, In Japanese Patent No. 5,439,582 and Japanese Patent Application Laid-Open No. 5-93807 (Nippon Paint),
We adopted low-temperature reaction type electrodeposition paint or replaced it with other expensive positive photoresist.However, low temperature reaction type electrodeposition paint has a short service life at room temperature of bath liquid, so Since few products have been commercialized and are not easily available, very few manufacturers have adopted such anionic electrodeposition method.

In order to avoid the problem that the anionic electrocoating material is altered by the photoresist developer, various electrocoating methods have been proposed in combination with a transfer technique. For example, Japanese Patent Application Laid-Open No. 5-164913. Publication (Dainippon Printing) and U.S. Pat. Nos. 4,853,092 (Dainippon Printing), 5,314,770 and 5,385,795 (Nippon Petroleum), 4,902. ，
No. 592 (Nippon Paint), European Regional Patent No. 02
Although there is 99508 (Nippon Paint Co., Ltd.) and the like, the transfer method still has a problem of insufficient accuracy, and it is difficult to increase the yield. As a method of solving the problem of modification with other photoresist developers, a cationic electrodeposition coating may be used. However, since a blackening reaction occurs in which cations reduce the conductive layer (ITO), light transmission The rate is significantly reduced and the color becomes dim. A method using such a method is disclosed in, for example, US Pat. No. 5,214,542 and Japanese Patent Laid-Open No. 4-32.
No. 4801, European wide area patent No. 0587033.
However, there was a problem that the light transmittance was insufficient in all of the above.

In addition to this, US Pat. No. 5,186,80
Some of the electrodeposition paints disclosed in No. 1 (Nippon Paint Co., Ltd.) are provided with photocurability, but while the problem of deterioration of the positive photoresist due to the developer can be avoided, an electrodeposition paint with a large pigment content can be used. Since it has photosensitivity,
It was technically difficult to achieve sufficient resolution.

[0013]

Based on the above-mentioned conventional techniques, in order to improve the utilization rate of the coating material, an anionic electrodeposition coating material having a high light transmittance is used, and at the same time, the development solution of the photoresist is used. It is an object of the present invention to solve the problem of deterioration of the thin film of the anionic electrodeposition resin layer and to solve the problem of difficulty in arranging colored pixels freely.

That is, according to the present invention, the positive photoresist can be removed by combining suitable conditions of exposure and post-baking, and the anionic electrodeposition thin film can be formed without damaging the anionic electrodeposition thin film. It is an object of the present invention to provide a method for manufacturing a color filter using an anionic electrocoating material, in which pixels are freely arranged while maintaining a high light transmittance, and the usage rate of a coloring coating material is high.

[0015]

The present invention comprises the steps of (1) partially coating a transparent photoresist on a transparent conductive substrate and then partially exposing the transparent conductive substrate through an exposure and development process. , (2) a step of selectively coating a colored electrodeposition resin layer on the exposed portion of the conductive substrate by the anionic electrodeposition method, and (3) the remaining positive-type photo Exposing the resist to full exposure,
(4) a step of heating and drying the transparent electrode substrate to cure the electrodeposition resin layer (post-baking), and (5) a step of removing the positive photoresist left by the alkaline developer. ) Repeating the above steps (1) to (5) to produce the remaining electrodeposition resin layers of different hues, the method for producing a color filter using an anionic electrodeposition paint.

In the present invention, the step (1) is
The present invention relates to a method for producing a color filter using an anionic electrodeposition paint, which is performed after a black matrix is formed on the transparent conductive substrate through the processes of coating, exposing and developing a black photosensitive paint.

The positive photoresist is preferably a photoresist system composed of a cresol novolac resin and a quinonediazide compound.

Further, it is preferable that the electrodeposition resin layer is prepared by using an emulsion of an anionic resin having a carboxyl group and performing deposition by electrodeposition.

The anionic electrodeposition method uses a voltage of 1
It is preferable that the voltage is 5 to 80 V and the electrodeposition time is 10 to 120 seconds.

Further, it is preferable that the whole surface exposure in the step (3) is such that the exposure amount is 20 mJ / cm ² or more.

Further, it is preferable that the whole surface exposure in the step (3) is an exposure amount of 40 mJ / cm ² or more.

Further, the heating and drying temperature in the step (4) is preferably 120 to 220 ° C.

Further, the heating and drying temperature in the step (4) is preferably 130 to 160 ° C.

Further, the heating and drying time in the step (4) is preferably 5 to 60 minutes.

The alkaline developer used in the step (5) is preferably an aqueous solution of sodium hydroxide, sodium metasilicate, potassium hydroxide or tetramethylammonium hydroxide.

The present invention also relates to a method for producing a color filter using an anionic electrodeposition paint, wherein the electrodeposition resin layer has three kinds of hues, and the three kinds of hues are red, green and blue hues. .

Further, the present invention provides the above-mentioned red, green and blue.
The shape of the electrodeposited resin layers of different hues is a fine lattice shape (in the present specification, “lattice shape” is a concept that the overlapping unit includes a triangle, a mosaic shape, and a stripe shape). The present invention relates to a method for manufacturing a color filter using an anionic electrodeposition paint, in which the overlapping arrangement method is an arrangement of triangles, mosaic shapes, or stripe shapes, and a black matrix is provided between each hue.

In the present invention, the transparent conductive substrate is I
The present invention relates to a method for manufacturing a color filter using an anionic electrodeposition coating material which is glass coated with TO (indium tin oxide).

In the present invention, the step (3) is
The present invention relates to a method for manufacturing a color filter using an anionic electrodeposition coating, which can be completed before the step (2), that is, anionic electrodeposition is performed only after the entire surface is exposed.

The present invention also includes the steps (1) to
(6) A method for producing a color filter using an anionic electrodeposition coating composition, in which the remaining one portion of the positive photoresist is peeled off and the last electrodeposition resin layer of one hue is directly coated.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) a step of fully coating a positive photoresist on a transparent conductive substrate and then partially exposing the transparent conductive substrate through an exposure and development process;
(2) A step of selectively coating a portion of the conductive substrate exposed by the exposure and development processes with a colored electrodeposition resin layer by an anionic electrodeposition method, and (3)
Exposing the remaining positive photoresist to full exposure; (4) heating and drying the transparent electrode substrate to cure the electrodeposition resin layer; and (5) using an alkaline developer. The method comprises the steps of peeling off the remaining positive photoresist, and (6) repeating the steps (1) to (5) to produce the remaining electrodeposited resin layers having different hues. ) Is a method for producing a color filter using an anionic electrodeposition paint, which is performed after a black matrix is formed on the transparent conductive substrate through a process of coating, exposing, and developing a black photosensitive paint. Explained.

In FIG. 1, (A) to (J) show steps in a color filter manufacturing method using an anionic electrodeposition paint, 1 is ITO, 2 is a glass plate, 3 is ITO glass, 4 is a black photosensitive paint. Coating layer, 5 is an arrow representing light irradiation, 6 is a negative photomask, 7 is a black matrix, 8 is a positive photoresist, 9 is an arrow representing light irradiation, 10 is a negative photomask, and 11 is a hue. A certain electrodeposition resin layer, 12 is an electrodeposition resin layer having another hue, and 13 is an electrodeposition resin layer having another hue.

If the black matrix 7 is needed,
As shown in FIG. 1, (A) an ITO glass (transparent conductive substrate) 3 including an ITO 1 and a glass plate 2 is prepared, and (B)
A coating layer 4 of a black photosensitive paint is applied to the ITO surface of the ITO glass 3, and (C) a black photosensitivity is obtained by light (represented by an arrow 5 representing light irradiation) through a negative photomask 6. A desired portion of the coating layer 4 of the paint is exposed, and (D) this is developed to prepare the black matrix 7, and (E) ITO glass IT
The positive photoresist is entirely coated on the O surface from above the black matrix, and the positive photoresist is exposed to light (represented by an arrow 9 representing light irradiation) through the negative photomask 10 (F). By exposing the desired part of (G) and developing it.
Expose the desired portion of the ITO surface of the O glass, and (H)
In the step (G), the exposed portion of the ITO surface is selectively coated with an electrodeposition resin layer having a hue by anionic electrodeposition coating, and then the remaining positive type photoresist is entirely exposed. Then, the ITO glass plate is post-baked (heated and dried), and (I) the positive photoresist left by the alkaline developer is peeled off. Further, the same steps as in (E) to (I) above (however, the exposed portion on the ITO surface in this step is different from the exposed portion in the same steps as in (F) and (G)).
Thus, the desired portion of the ITO surface is coated with the electrodeposition resin layer 12 having another hue (different hue). Further, by the steps similar to the above (E) to (I) (however, the exposed portion on the ITO surface in the same step as (F) and (G) at this time is different from the above exposed portion), A desired portion of the ITO surface is coated with the electrodeposition resin layer 13 having another hue (further different hue). In this way, a color filter having a desired hue can be manufactured. In Fig. 1, (J) is
A color filter having a black matrix 7, an electrodeposition resin layer 11 having a hue, an electrodeposition resin layer 12 having another hue, and an electrodeposition resin layer 13 having another hue on the ITO surface is shown. It should be noted that the hues of the electrodeposition resin layer 11 having a hue, the electrodeposition resin layer 12 having another hue, and the electrodeposition resin layer 13 having another hue are red, green and blue, respectively. A color filter having a green / blue hue can be manufactured.

If the black matrix 7 is unnecessary, the steps (B) to (D) may be omitted and the color filter may be manufactured by the steps (A) and (E) to (J).

In the present invention, an anionic electrodeposition method is adopted and combined with a positive photoresist, and
By improving the manufacturing process conditions of the prior art (adding an overall exposure step before post-baking (post-baking)) and raising the post-baking (post-baking) temperature to 120 ° C. or higher, the positive photoresist is cured. The anionic electrodeposition film should be sufficiently hardened to withstand deterioration by a developing solution. In this way, while maintaining the high transmittance of the anionic electrodeposition method, the problem of blackening the ITO glass of the cationic electrodeposition method can be avoided, and the shape of the black matrix can be freely designed. Can be said to be a technology with rich potential.

The anionic electrodeposition film according to the present invention is applied on the conductive layer of a transparent conductive substrate, and the transparent conductive layer has excellent light transmittance and excellent conductivity. Since a liquid crystal display is an electronic component having extremely high precision requirements, it is desirable to use glass as the transparent conductive substrate in consideration of dimensional stability and cell gap stability of the two-layer glass. Regarding the conductive layer, an ITO thin film is usually adopted, and has a light transmittance of at least 80% or more. Further, in order to suppress the influence on the uniformity of the resistance of the conductive layer during electrodeposition, the conductivity of ITO is preferably set to 15Ω / □ or less. In addition, it is also impossible that the conductivity is too low, in which case the ITO becomes too thick and the light transmittance decreases.

The color filter film of the liquid crystal display is
It is usually composed of three kinds of red, green, and blue electrodeposition coatings, most of which are arranged in stripes or grids.
Although different types of colors are arranged alternately, black stripes (black matrix) are used to improve the contrast between the colors of the color filter film.
To prevent the colors from being directly adjacent. This black stripe (black matrix) is formed in a stripe shape or a lattice shape according to the shape of the color filter film, and as a material, a metal containing chromium or nickel, or carbon black or a black color in which many pigments are mixed. It can be an organic material.
If a metal material is used, coating by a sputtering method or film formation by a plating method can be used. If an organic material is used, an organic solution in which a black pigment is dispersed is generally used, and spin coating or electrodeposition can be used as a coating method. Generally speaking, a metal material has a high reflectance and thus affects the chromaticity of color, but it has a good light-shielding property and effectively blocks the backlight, thus improving the resolution. Organic materials have low reflectance, but do not have sufficient light-shielding properties, and therefore improvements in the materials are required. In the present invention, a photosensitive resin layer in which a black pigment is dispersed is selected for convenience of production.

In the present invention, the positive type photoresist is used as an insulating film during electrodeposition by the anionic electrodeposition method, that is, a thin film for protecting a portion of the transparent conductive layer which does not require electrodeposition, and a portion to be electrodeposited is exposed. This makes it possible to electrodeposit only a desired portion. The main component of the positive photoresist is composed of a cresol novolac resin and a photosensitive quinonediazide compound.Because the decomposition reaction of the quinonediazide compound proceeds in the exposed portion of the photoresist, a carboxyl group is generated. The photoresist can be dissolved in an alkaline developing solution. The non-exposed portion is hydrophobic and thus does not dissolve in an alkaline developing solution. The unexposed portion of the positive photoresist is likely to cause a thermal crosslinking reaction at a high temperature and at the same time loses photodegradability. Therefore, the prebaking drying temperature limit value is usually set to about 100 ° C. 100
When the temperature is higher than 0 ° C, a thermal crosslinking phenomenon occurs, which makes removal difficult or causes scum to remain. Regarding the already exposed portion, the quinonediazide group is decomposed to generate a carboxyl group, but the reaction between this carboxyl group and the hydroxyl group of the cresol novolac resin is
The problem of thermal cross-linking does not have to be taken into consideration because it does not easily occur unless the temperature is higher than 200 ° C.

Generally, the prebaking temperature of the positive photoresist is 80 to 100 ° C. The film thickness is adjusted depending on the viscosity and the rotation speed of the spin coating, and the suitable viscosity is 5 to 60 cps and the suitable rotation speed is 1200 to 4000 rpm. Since the film thickness affects the insulating property and the developability, the film thickness is usually 1.0 μm to 3.
It is adjusted to the range of 0 μm. The exposure dose varies depending on the product, but is about 40 to 200 mJ / cm ² , and if the exposure dose is too large, the line edge is reduced due to alteration, which is not preferable. The developing solution is an aqueous solution of sodium hydroxide, potassium hydroxide, sodium metasilicate, tetramethylammonium hydroxide, etc., and the concentration is in the range of 0.5 to 3%.

After development of the positive photoresist,
The exposed portion of the transparent conductive layer is coated with an electrodeposition coating film by an electrodeposition method. In the present invention, an anionic electrodeposition coating is used for electrodeposition, and the main components are acrylic resin, melamine resin, pigment, neutralizing agent, solvent and water.

The acrylic resin of the present invention is anionic and has a carboxyl group. It is a copolymer and is synthesized from various kinds of acrylic monomers, and preferable monomers are as follows. (1) Monomers having a carboxyl group: for example, acrylic acid and methacrylic acid. (2) Monomer having hydroxyl group: For example, 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate. (3) Aryl group-containing monomer: for example, styrene,
Benzol acrylate, benzol methacrylate,
2-phenoxymethyl acrylate. (4) Monomer having an alkyl group: for example, methyl methacrylate, methyl acrylate, butyl acrylate, butyl methacrylate.

Suitable monomers are selected from the above-mentioned monomers and polymerized by a solvent polymerization method. As the thermal polymerization initiators which are usually used, there are azobisisobutyronitrile and benzoyl peroxide.

Melamine resin is a commonly used thermosetting resin, which is stable at room temperature, has a fast reaction at high temperature, and reacts with the hydroxyl group and carboxyl group of the acrylic resin used in the present invention. It can have good crosslink density and high transmittance. The amount of the thermosetting resin used is 10 to 4 of the acrylic resin.
0% by weight.

The pigments compatible with the present invention must have good heat resistance and light resistance, high transmittance, and be easily dispersed. Suitable pigments are as follows. Red-177, Red-209, Red-14
9, Green-36, Blue-15: 3, Blue-1
5: 4, Blue-15: 6, Yellow-109, Yellow-139, Yellow-83, Violet-23 and the like.

Ciba Geigy, B
Examples include ASF, ICI, Hoecst.

Since most of the pigments are sticky when purchased,
In order to improve the transmittance, it is necessary to polish the pigment into fine particles, and suitable polishing equipment includes a sand mill, a ball mill, an attritor, a three roll mill and the like. Further, a dispersion aid, a leveling agent, and a coupling agent can be mixed in order to maintain the fluidity of the pigment. A suitable pigment mixing amount is 15 to 3 of the acrylic resin.
0% by weight. If it is too large, precipitation will occur, and if it is too small, the color saturation will be insufficient.

In order to make the resin into an emulsion having a charge, the carboxyl groups of the acrylic resin are neutralized with a neutralizing agent to obtain a chargeable resin. Suitable neutralizing agents include ammonia. For example, there are ammonia water, triethylamine, triethanolamine and the like. The amount of the neutralizing agent used is 40 to the carboxyl group equivalent of the acrylic resin.
100% by weight.

Further, as a suitable solvent, those which can form a stable emulsion without causing precipitation and whose film thickness can be adjusted are preferable, and the following solvents can be used.

Examples include methyl ethyl ketone, isopropyl alcohol, n-butanol, propylene glycol monomethyl ether and ethylene glycol ether.

Generally, in the method for producing an anionic electrodeposition coating composition, the pigment is first ground into fine particles, which are then mixed with an acrylic resin, a melamine resin and a solvent and sufficiently stirred, and a neutralizing agent is further added. After sufficiently stirring, the mixture is sufficiently stirred while slowly injecting deionized water in a dropping manner. If the deionized water is dropped too fast, a resin with large particles will be formed, and clogging will occur during filtration.

The transparent conductive substrate after the development of the photoresist is suspended in the positive electrode in the electrodeposition bath, the negative electrode is made of stainless steel, and the distance between the two electrodes is set to 10 cm or more to prevent short circuit. Many color filter film pixels of the same color are generally quadrangular, and the length and width are 80
To 150 μm. After energization, an anionic electrodeposition coating material is deposited on these exposed conductive layers, but the printing voltage is generally 20 to 20 depending on the film thickness and the content of the compound.
It is set to 80V. If the voltage is too high, the film thickness will be too thick, and if the voltage is too low, the pigment will be difficult to deposit together with the resin, and the tint will be too light. The electrodeposition time is generally in the range of 10 to 60 seconds. If the electrodeposition time is too short, the film thickness becomes uneven, and if it is too long, the film thickness becomes too thick, which affects the yield. The film thickness can be adjusted depending on the voltage and the content of the formulation, but generally 1.0 to 2.
5 μm.

The anionic electrodeposition coating composition used in the present invention has the advantages of high transmittance and no yellowing phenomenon. The cationic electrodeposition coating composition has a drawback that it is yellowed by oxygen because the cationic resin itself contains an amino group. Moreover, since the cationic electrodeposition coating material is deposited on the negative electrode, the reduction blackening phenomenon of ITO occurs and the transmittance decreases.

In general, the electrodeposition coating composition is in a mild gel state even after being deposited, and is easily dissolved in a solvent, so that it cannot have strong chemical resistance until it is cured by post baking. If the thermosetting is directly proceeded after the electrodeposition coating is deposited, the positive photoresist on the conductive layer also proceeds with the thermal crosslinking reaction at the same time, so that the removal of the positive photoresist becomes difficult. Alternatively, they remain as scum and affect the deposition of other hues. In order to solve this problem, the present invention exposes the entire surface of the positive photoresist before post-baking to decompose the quinonediazide group into hydroxyl groups, thereby suppressing the thermal crosslinking reaction of the positive photoresist. The generated hydroxyl groups assist removal cleaning in the photoresist stripping step. A suitable total exposure amount varies depending on the photoresist, but generally 40 mJ / cm ² or more can remove and clean the photoresist film. As a stripping agent for the positive photoresist, an aqueous solution of sodium hydroxide, an aqueous solution of potassium hydroxide, an aqueous solution of tetramethylammonium hydroxide or the like can be used, and the concentration is preferably 2 to 5% by weight.

After the positive photoresist coating, exposure, development, electrodeposition coating coating, overall exposure and post-baking as described above, the photoresist is peeled off to complete the production of the colored resin film of the first hue. However, since the color filter plate is generally provided with three types of color filters of red, green, and blue, the production of three color filters is completed by repeating the above steps (see FIG. 2). If it is not necessary to insulate the outer periphery of the color filter plate with a colorless or transparent coating, the exposed transparent layer after curing the colored resin film of the second hue and removing the photoresist by the method shown in FIGS. By forming the colored resin of the third hue directly on the conductive layer, the number of times of photoresist can be simplified by one.

[0055]

[Examples] The present invention will now be specifically described with reference to Synthesis Examples, Examples and Comparative Examples, but the present invention is not limited thereto.

Synthesis Example 1 Synthesis of acrylic resin A condenser tube, a thermometer, a feeder tube and a stirring rod were inserted into a 4-neck reaction flask, respectively, and the temperature was raised to 10 by heating in an oil bath.
It was controlled at 0 ° C. 338.0 g of polyethylene glycol monomethyl ether was added to the reaction flask, and nitrogen gas was injected. 390.0 g of methacrylic acid, 17
7.0 g of 2-hydroxyethyl acrylate and 1
735.0 g of 2-phenoxyethyl acrylate,
1152.0 g butyl acrylate and 600.0 g
Of methyl methacrylate, 30.0 g of azobisisobutyronitrile, and 1738.0 g of propylene glycol monomethyl ether were prepared, and the solution was added to the reaction flask by a dropping method.
It was added dropwise at 00 minutes. After the dropping was completed, the same temperature was maintained for 3 hours and then cooled to obtain a transparent acrylic resin. The average molecular weight was 31,000.

Synthesis Example 2 Preparation of Anionic Electrodeposition Coating Acrylic resin, melamine resin, pigment and propylene glycol monomethyl ether shown in Table 1 were mixed and stirred sufficiently, and then placed in a sand mill to continue the pigment for 10 hours. And then polished. This colored resin mixture was placed in a stirring tank, the ammonia (aqueous solution) shown in Table 1 was added, and the mixture was sufficiently stirred,
The deionized water shown in Table 1 was slowly added dropwise to the stirring tank in about 1 hour, and the mixture was continuously stirred for 2 hours or more and then filtered to obtain three kinds of anionic electrodeposition paints of red, green and blue. Got

[0058]

[Table 1]

Example 1 One sheet of commercially available ITO glass (Merck Co. 1.1 mm 1
A positive photoresist (cresol novolac resin + quinone diazide compound) was entirely coated on ITO of 0Ω / □ by a spin coating method. The rotation speed at this time was 2500 rpm. This was placed in an oven, dried at 90 ° C. for 10 minutes, and then cooled. A negative photomask having overlapping fine lines and a square dot pattern with a size of 5 to 150 μm was placed on the photoresist film, and an exposure dose of 120 mJ / cm ² was irradiated by a medium pressure mercury lamp, and then 2% by weight of metasilicic acid was used. The exposed portions of the photoresist which were developed in sodium (aqueous solution) were dissolved and removed. The exposure time was about 60 seconds. The ITO glass substrate which had been subjected to such steps was immersed in an electrodeposition bath containing the red anionic electrodeposition coating material prepared in Synthesis Example 1 and Synthesis Example 2 and was electrodeposited at 45V. The electrodeposition time is 15
Seconds. A red anionic electrodeposition coating was deposited on the exposed ITO areas of the ITO glass. Although the film thickness was about 2.0 μm, the other part of the ITO glass was protected by the positive photoresist and an electrodeposition film was not formed. After that, the ITO glass substrate was taken out, washed with water, and then dried at 90 ° C. The drying time was 10 minutes. After cooling this, whole surface exposure was performed with a medium-pressure mercury lamp without covering the negative photomask. The exposure dose at this time was 40 mJ / cm ² . At this time, the positive photoresist was irradiated and the photosensitive quinonediazide group was decomposed to generate a carboxyl group. Then ITO
The glass substrate was placed in an oven at 120 ° C. to cure the anionic electrodeposition coating film. The curing time was 5 minutes. At this time, since only a small amount of the quinonediazide group remained in the photoresist, the thermal crosslinking reaction due to the high temperature of the photoresist did not occur. When the glass substrate was immersed in 5% by weight of sodium hydroxide (aqueous solution) for 2 minutes after the electrodeposition coating film was cured, the photoresist was dissolved and removed, and the anionic electrodeposition coating film was not damaged.

ITO coated with a red filter film
The entire surface of the ITO of the glass substrate was coated with a second positive photoresist, and the same steps were used to expose, develop, and synthesize example 1 and example 2 through a negative photomask.
The green anionic electrodeposition coating material prepared in the above was coated, dried, exposed on the whole surface, the electrodeposition coating film was cured by heating, and the photoresist was peeled off to obtain an ITO glass substrate coated with red and green filter films. Furthermore, when a blue area was produced by the same method, a color filter plate having three types of patterns of red, green and blue could be obtained.

Examples 2 to 9 The manufacturing steps are the same as in Example 1, but the process conditions are different. The types of positive photoresist, the total exposure amount, the post bake temperature and the post bake time are shown in Table 2. A color filter plate was obtained in the same manner as in Example 1 except that the color filter plate was changed as described above.

The minimum resolution line width of the color filter film of each example is as shown in Table 2, and the resolution is 20 in each case.
The level of less than μm was achieved.

[0063]

[Table 2]

Comparative Examples 1 to 3 The manufacturing steps are the same as in Example 1, but the process conditions are different, and the types of positive photoresist, post bake temperature and post bake time are as shown in Table 2. A color filter plate was obtained in the same manner as in Example 1 except that the whole exposure was not performed before the post-baking. The photoresist of each comparative example could not be effectively removed and cleaned, and scum remained. Even if the entire surface was exposed after the post-baking, the solubility of the photoresist could not be improved.

Comparative Example 4 The manufacturing steps were the same as in Example 1, but the process conditions were different, and the post-baking temperature was set to 100 in order to avoid the thermal crosslinking reaction of the positive photoresist.
A color filter plate was obtained in the same manner as in Example 1 except that the temperature was lowered to 0 ° C., the post bake time was set to 2 minutes, and the entire surface exposure was not performed. As a result, although the photoresist did not undergo a thermal crosslinking reaction, the post-bake temperature was low, and the curing of the electrodeposition coating film was insufficient.When the photoresist was peeled off, the electrodeposition coating film was also altered by the developer and dissolved. have done.

Example 10 One sheet of commercially available ITO glass (Merck Co. 1.1 mm 1
A photosensitive black paint (trade name “CK-20” manufactured by Fuji Hunt Co., Ltd.) on ITO of 0Ω / □ by a spin coating method.
00 ") was coated on the entire surface. The rotation speed of spin coating at this time was 1200 rpm. IT
The O glass substrate was placed in an oven and dried at 80 ° C. for 10 minutes. The black coating film was covered with a negative photomask and exposed with a medium-pressure mercury lamp. The exposure dose at this time is 200 mJ / cm
^{Was 2} . At this time, the photo-curing reaction was allowed to proceed in the exposed area, and the uncured portion was developed and removed with a 1 wt% potassium hydroxide aqueous solution. At this time, ITO
A black grid pattern (black matrix) was formed on the glass substrate. When the ITO glass substrate was placed in an oven at 200 ° C. and cured for 30 minutes, the black matrix was completely cured. After cooling, the positive photoresist (cresol novolac resin + quinone diazide compound) was entirely coated on the ITO and the black matrix of the ITO glass substrate by spin coating. The rotation speed of spin coating at this time was 2500 rpm. I through such a process
The TO glass substrate was placed in an oven, dried at 90 ° C. for 10 minutes, and then cooled. A negative photomask having a pattern corresponding to the position where the red color filter film is to be formed is placed on the photoresist film, and the negative pressure photomask 120 is formed by a medium pressure mercury lamp.
After irradiating with an exposure amount of mJ / cm ^2, the exposed photoresist was dissolved and removed by developing in 2% by weight of sodium metasilicate (aqueous solution). The exposure time at this time is about 60
Seconds. The ITO glass substrate passed through the above steps was immersed in an electrodeposition bath containing the red anionic electrodeposition coating material prepared in Synthesis Example 1 and Synthesis Example 2 and electrodeposition coating was performed at 45V. The electrodeposition time was 15 seconds. A red anionic electrodeposition coating was deposited on the exposed ITO portion of the ITO glass. Although the film thickness was about 2.0 μm, the other part of the ITO glass was protected by the positive photoresist and an electrodeposition film was not formed. After that, the ITO glass substrate was taken out, washed with water, and then dried at 90 ° C. The drying time was 10 minutes. After cooling this, whole surface exposure was performed by a medium-pressure mercury lamp without covering the negative photomask. The exposure amount at this time was 100 mJ / cm ² . At this time, the positive photoresist was irradiated and the photosensitive quinonediazide group was decomposed to generate a carboxyl group. Then, the ITO glass substrate was placed in an oven at 135 ° C. to cure the anionic electrodeposition coating film. The curing time was 15 minutes. At this time, since only a small amount of the quinonediazide group remained in the photoresist, the thermal crosslinking reaction due to the high temperature of the photoresist did not occur. After the anionic electrodeposition coating is cured, the glass substrate is
Immersion in a weight% of sodium hydroxide (aqueous solution) for 2 minutes dissolved and removed the photoresist, and did not damage the anionic electrodeposition coating film.

The ITO glass substrate coated with the above-mentioned black matrix and red coating film was exposed, developed and synthesized through a negative photomask by the same steps.
And coating of the green anionic electrodeposition coating composition or the blue anionic electrodeposition coating composition prepared in Synthesis Example 2, drying, whole surface exposure, heat curing of the anionic electrodeposition coating film, and peeling of the photoresist were repeated to produce green and When a blue electrodeposition coating film was prepared, a glass substrate having a black matrix and three color electrodeposition coating films of red, green and blue was obtained. The color filter plate was completed by heating this at 200 degreeC for 1 hour.

FIG. 5 is a spectral characteristic diagram of three colors of red, green and blue of this color filter plate.

[0069]

As described above, according to the method of manufacturing a color filter using the anionic electrodeposition coating composition of the present invention, the following effects can be obtained.

(1) Since an anionic electrodeposition coating material can be used, the transmittance is high, there is no need to lower the post-baking temperature, and a generally commercially available positive photoresist can be used.

(2) Since the paint utilization rate is superior to that of the pigment dispersion method, the paint cost can be reduced. (3) The problem that the cation reduces the ITO blackening does not occur.

(4) The shape of the black matrix can be freely designed.

Therefore, not only can it be applied to the STN type, but it can also be applied to the more complicated TFT type and has an excellent paint utilization rate, so it can be said to be an extremely useful technique.

[Brief description of drawings]

FIG. 1 is a process diagram showing a color filter manufacturing method (without an ITO pattern) using an anionic electrodeposition coating material according to the present invention, and (A) to (J) are cross-sectional views of ITO glass, coating layers, etc. It is explained using.

FIG. 2 is a process drawing showing a color filter manufacturing method (without an ITO pattern) using an anionic electrodeposition coating material according to the present invention.

FIG. 3 is a process drawing showing an example in which the process of FIG. 2 is partially simplified.

FIG. 4 is a process drawing showing another example in which the process of FIG. 2 is partially simplified.

FIG. 5 is a spectral characteristic diagram showing spectral characteristics of red, green and blue anionic electrodeposition coating films.

[Explanation of symbols]

 1 ITO 2 Glass Plate 3 ITO Glass 4 Black Photosensitive Paint Coating Layer 5 Light (Arrow Representing Light Irradiation) 6 Negative Photomask 7 Black Matrix 8 Positive Photoresist 9 Light (Arrow Representing Light Irradiation) 10 Negative Photomask 11 Electrodeposited resin layer with hue 12 Electrodeposited resin layer with another hue 13 Electrodeposited resin layer with another hue

Claims (16)

[Claims] 1. A step of (1) completely coating a positive photoresist on a transparent conductive substrate and then partially exposing the transparent conductive substrate through an exposure and development process, and (2) anionic electrodeposition. Selectively coating a portion of the conductive substrate exposed by the exposure and development process with a colored electrodeposition resin layer by a method, and (3) exposing the remaining positive photoresist to full exposure. And (4) heating and drying the transparent electrode substrate to cure the electrodeposition resin layer,
(5) a step of removing the positive photoresist left by the alkaline developer, and (6) the step (1) to
A method of manufacturing a color filter using an anionic electrodeposition coating material, which comprises repeating (5) to prepare the remaining electrodeposition resin layers having different hues. 2. The anionic electrodeposition according to claim 1, wherein the step (1) is performed after a black matrix is formed on the transparent conductive substrate through a process of coating a black photosensitive paint, exposing and developing. Color filter manufacturing method using paint. 3. The method for producing a color filter using an anionic electrodeposition coating composition according to claim 1, wherein the positive photoresist is a photoresist system composed of a cresol novolac resin and a quinonediazide compound. 4. The production of a color filter by an anionic electrodeposition coating composition according to claim 1, wherein the electrodeposition resin layer is produced by using an emulsion of an anionic resin having a carboxyl group and depositing by electrodeposition. Method. 5. The anionic electrodeposition method uses a voltage of 15 to
The method for producing a color filter using the anionic electrodeposition coating composition according to claim 1, wherein the electrodeposition time is 80 V and the electrodeposition time is 10 to 120 seconds. 6. The method for producing a color filter with an anionic electrodeposition coating composition according to claim 1, wherein the overall exposure in step (3) is performed with an exposure amount of 20 mJ / cm ² or more. 7. The method for producing a color filter with an anionic electrodeposition coating composition according to claim 1, wherein the overall exposure in step (3) is performed with an exposure amount of 40 mJ / cm ² or more. 8. The heating and drying temperature in step (4) is 1
The method for producing a color filter using the anionic electrodeposition coating composition according to claim 1, wherein the temperature is 20 to 220 ° C. 9. The heating and drying temperature in step (4) is 1
The method for producing a color filter using the anionic electrodeposition coating composition according to claim 1, wherein the temperature is 30 to 160 ° C. 10. The method for producing a color filter with an anionic electrodeposition coating composition according to claim 1, wherein the heating and drying time in the step (4) is 5 to 60 minutes. 11. The anionic electrodeposition according to claim 1, wherein the alkaline developer used in the step (5) is an aqueous solution of sodium hydroxide, sodium metasilicate, potassium hydroxide or tetramethylammonium hydroxide. Color filter manufacturing method using paint. 12. The method for producing a color filter with an anionic electrodeposition coating composition according to claim 1, wherein the electrodeposition resin layer has three kinds of hues, and the three kinds of hues are red, green and blue hues. . 13. The red, green and blue electrodeposited resin layers of three kinds of hues are in the form of a fine grid, and the overlapping arrangement method is an arrangement of triangles, mosaics or stripes. 13. The method for producing a color filter using the anionic electrodeposition coating composition according to claim 2 or 12, wherein a black matrix is provided between the respective hues. 14. The method for producing a color filter using an anionic electrodeposition coating composition according to claim 1, wherein the transparent conductive substrate is glass coated with ITO (indium tin oxide). 15. The method for producing a color filter using an anionic electrodeposition coating composition according to claim 1, wherein the step (3) can be completed before the step (2). 16. After the steps (1) to (6), the last one is left on the portion where the remaining positive photoresist is stripped off.
The method for producing a color filter using the anionic electrodeposition coating composition according to claim 1, wherein the electrodeposition resin layer of one hue is directly coated.