JPH1020110A - Production of color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color filter producing method capable of uniformizing film thickness by controlling the thickness of each color film after sticking photosensitive layers thereby reducing difference in the surface level of pixels. SOLUTION: This method includes a process to laminating a photosensitive film comprising a base film and a colored photosensitive resin layer on a transparent substrate in such a manner that the colored photosensitive resin layer faces the substrate, a process to expose the resin layer according to a pattern and a process to develop. These processes are repeated to form a multicolored pattern to obtain a color filter. In this method, a process to heat the film to increase the film thickness is carried out succeeding to the exposing process.

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.

[0002]

2. Description of the Related Art A color filter is formed by forming two or more kinds of very fine stripe-like or mosaic-like patterns having different hues on a surface of an optically transparent substrate such as glass at a predetermined interval. Or they are arranged crossing each other. In these patterns, it is necessary to arrange the hues in a predetermined order and at predetermined intervals, and to form a uniform layer with less thickness unevenness, and to use a color filter such as a screen printing method, a photolithography method, and a dyeing method. Manufacturing methods have been proposed.

There is also known a method of manufacturing a color filter which can easily form a multicolor fine stripe or mosaic pattern with high accuracy using a base film and a photosensitive film having a photosensitive resin layer. I have.

[0004] As a method of producing a color filter using a photosensitive film, a photosensitive resin composition colored in one color is applied to a base film, and the photosensitive resin layer of the photosensitive film is dried on a transparent substrate. And a pattern is formed by exposing and developing through a predetermined pattern mask (JP-A-61-99102, JP-A-3-16-16).
0454, JP-A-3-111802, JP-A-2-151805, JP-A-4-212161, JP-A-4-301602, JP-A-5-21
No. 07 publication).

[0005] In order to obtain a good pattern, it is necessary for the photosensitive film to have an improved ability to follow the substrate. As a method for improving the followability of a photosensitive film, for example, a three-layer resist method (J.Va.) characterized in that even if the substrate has a step, the substrate can be finely processed accurately.
c.Sci.Technol., Vol. 16, page 1620, published in 1968), the photosensitive resist layer is exposed at 50 to 150 ° C. and 30 to 6 after exposure before development.
An after-bake method in which heating is performed under the condition of 0 second to promote the reaction of the lower layer portion that is not sufficiently irradiated with UV light (Japanese Patent Laid-Open No. 3-1)
96596) and the like. In addition, a color filter using a pigment-dispersed photopolymer promotes the generation of monomer radicals induced by photoinitiator radicals and the polymerization chain reaction, and applies a photosensitive resist layer using a spinner to remove the solvent. Pre-baking method (for example, at 85 ° C. for 5 minutes) (J. Photopol
Sci. Technol., Vol. No. 2, 1989, 244-248).

[0006] In the case of a color filter, it is formed from red, green, blue and / or black pixels. It is required that the pixel thicknesses are all the same. That is, it is considered that the step of the film thickness between pixels is preferably within 0.1 μm. This is a characteristic required for preventing disconnection of ITO and ensuring uniformity of liquid crystal alignment. This can be achieved by coating in which the film thickness of each color is adjusted to within 0.1 μm, but the coating technique is difficult and cannot always be completely adjusted.
Even if the film thickness of each color film is not uniform, if the film thickness can be adjusted after the photosensitive layer is attached, the step between pixels of the color filter can be reduced as a result.

[0007]

An object of the present invention is to provide a method of manufacturing a color filter which can adjust the film thickness of each color after the photosensitive layer is attached, reduce the step between pixels, and make the film thickness uniform. To provide.

[0008]

According to the present invention, a photosensitive film comprising a base film and a colored photosensitive resin layer is provided on a transparent substrate, and (1) the colored photosensitive resin layer is provided on the substrate. In the method of manufacturing a color filter for forming a multicolor pattern by repeating the step of bonding to face each other, the step of (2) exposing in a pattern, and the step of (3) the step of developing, the step following (2) And a step of heating to increase the film thickness.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the formation of a pattern having a tapered pixel cross section according to the present invention, the heating time and the heating temperature are controlled to increase the film thickness so that a desired film thickness is obtained after the step (2). It is achieved by performing the steps of obtaining. This is for the following reason. After the exposure step, there is crosslinking of the binder and generation of a polymer in the exposed portion. Since the monomer reacts to become a polymer, the concentration of the monomer decreases in the exposed area. When sufficient temperature and time are given, unreacted monomer moves from the unexposed portion to the exposed portion. That is, monomer migration occurs. The higher the temperature, the sooner the monomer moves. This phenomenon continues until the monomers are homogenized. As a result, the density of the exposed portion increases, and the film thickness also increases. By the way, the monomer that has moved after the exposure reacts and becomes polymerized while the radical generated by the exposure of the photoinitiator is alive.

In the present invention, heating is carried out after the exposure while the radicals are active, to promote the transfer of the monomer and the reaction. The moved monomer reacts. After that, when the base film is peeled off, the radicals are deactivated due to oxygen inhibition, and the reaction of the monomer is stopped. For the above reasons, a desired film thickness can be obtained by increasing the film thickness by controlling the heating time and the heating temperature, and the step between the pixels can be controlled. Normal,
It is known that the time for which the radical maintains its activity is around 15 minutes. After re-exposure, the base film is peeled off by heating, and the surface roughness of the photosensitive layer is measured. When exposed, the exposed portion becomes convex in the unexposed portion and the exposed portion, and becomes higher than the unexposed portion. In other words, it indicates that the group of monomers becomes more convex in the exposed portion.

In the present invention, a step between pixels can be controlled by utilizing the movement of the monomer. After the step (2), if the development is performed as it is, the thickness of the pixel becomes the same as that of the photosensitive resin layer before the attachment. In the present invention, heating is performed subsequent to the step (2). During this heating, by controlling the heating time and the heating temperature, the film thickness can be increased and a desired film thickness can be obtained. The higher the temperature, the more the monomer moves. The longer the time, the greater the amount of movement. Since the time for which the radical remains active is about 15 minutes, after the radical becomes inactive, the monomer moves,
Since there is no reaction, monomers that have moved but not reacted are dissolved and removed during development. When the base film is peeled off, oxygen inhibition starts immediately and the reaction stops. The film thickness can be controlled by setting a heating temperature after exposure and heating the film to peel off the base film when the increase in the film thickness reaches a desired value. The heating temperature can be set at room temperature or higher and at or below the thermosetting temperature. The heating time is at most during the radical activity. As the heating means, a usual dryer, hot water or other heating device can be used. Usually, the heating temperature is 6
0-100 ° C., and the heating time is 1-60 minutes.

Examples of the transparent substrate in the present invention include a glass plate and a plastic plate. The thickness of the transparent substrate is usually 0.4 to 4 mm. Examples of the base film in the present invention include a polyester film made of polyethylene terephthalate and the like, and a polyolefin film made of polyethylene, polypropylene and the like. The thickness of the base film is usually 3
５０50 μm.

The photosensitive film used in the present invention is obtained by applying a colored photosensitive resin composition onto a transparent base film, for example, a film such as polyethylene terephthalate, and drying the colored photosensitive resin layer. Is formed. This colored photosensitive resin layer is uncured,
Since it is flexible and sticky, it is desirable to further attach a protective film such as a polyethylene film thereon to prevent external damage and adhesion of foreign substances. The colored photosensitive resin layer formed on the photosensitive film is laminated on a transparent substrate while peeling off the protective film,
The base film on the surface of the colored photosensitive resin layer is removed after exposure through a negative pattern having a predetermined pattern.

As the photosensitive resin composition of the present invention, known ones can be used without particular limitation.
Those containing (A) an ethylenically unsaturated compound, (B) a carboxyl group-containing film imparting polymer, (C) a photopolymerization initiator, and (D) a pigment or dye are preferred.

As the ethylenically unsaturated compound (A),
For example, compounds obtained by adding an α, β-unsaturated carboxylic acid to a polyhydric alcohol (trimethylolpropane diacrylate, trimethylolpropane triacrylate, tetramethylolmethane triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate) Acrylate), compounds obtained by adding an α, β-unsaturated carboxylic acid to a glycidyl group-containing compound (trimethylolpropane triglycidyl ether triacrylate, bisphenol A diglycidyl ether diacrylate, etc.), polyvalent carboxylic acid (anhydride) Esterified product of a compound having a hydroxyl group and an ethylenically unsaturated group (such as β-hydroxyethyl acrylate), an alkyl ester of acrylic acid (methyl acrylate, ethyl acrylate, Butyl acrylate, 2-ethylhexyl acrylate, etc.), urethane diacrylate compound obtained by reacting trimethylhexamethylene diisocyanate with dihydric alcohol and divalent acrylic acid monoester, alkylene oxide of bisphenol A (ethylene oxide, Compounds having a hydroxyl group and an ethylenically unsaturated group (β-
Esterified with hydroxyethyl acrylate (2,2-bis [(4-acryloxypentaethoxy))
Phenyl] propane), γ-chloro-β-hydroxypropyl-β′-acryloyloxyethyl-o-phthalate, and the corresponding methacrylate. These compounds are used alone or in combination of two or more.

From the viewpoints of photosensitivity and developability, the amount of the component (A) is preferably 90 to 50 parts by weight based on 100 parts by weight of the total of the components (A) and (B).

(B) The carboxyl group-containing film imparting polymer includes, for example, a copolymer of alkyl acrylate or alkyl methacrylate and acrylic acid or methacrylic acid, an alkyl acrylate or alkyl methacrylate and acrylic acid. Copolymers of an acid or methacrylic acid with a vinyl monomer copolymerizable therewith are exemplified.

Examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate. Examples of the alkyl methacrylate include those corresponding to the above-mentioned alkyl acrylate. Examples of the copolymerizable vinyl monomer include, for example,
Dimethylaminoethyl acrylate, tetrahydrofurfuryl acrylate, aminoethyl acrylate, 2,2,2-trifluoroethyl acrylate,
2,2,3,3-tetrafluoropropyl acrylate, methacrylate, acrylamide, methacrylamide diacetone acrylamide, styrene, vinyltoluene and the like corresponding thereto.

Examples of (B) carboxyl group-containing film-imparting polymers include polyesters such as terephthalic acid, isophthalic acid and sebacic acid, copolymers of butadiene and acrylonitrile, cellulose acetate, cellulose acetate butyrate, methylcellulose and ethylcellulose. Can also be used in combination. The use of the component (B) improves the coating properties and the film properties of the cured product, and the compounding amount is preferably from 10 to 50 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B). . The amount is 1
If the amount is less than 0 parts by weight, the amount of the ethylenically unsaturated compound increases, so that the photosensitivity tends to decrease. If the amount exceeds 50 parts by weight, the photocured product tends to become brittle. The weight average molecular weight of the component (B) is 1 from the viewpoint of the coating properties and the film strength.
It is preferably from 000 to 500,000. The weight average molecular weight is a value measured by gel permeation chromatography and converted into polystyrene.

Examples of the photopolymerization initiator (C) include aromatic ketones (benzophenone, N, N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), 4-methoxy-4'-dimethyl) Aminobenzophenone, 4,4'-diethylaminobenzophenone, 2-
Ethyl anthraquinone, phenanthrene quinone, etc.), benzoin ether (benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether, etc.), benzoin (methyl benzoin, ethyl benzoin, etc.), 2,4,5-triarylimidazole dimer, 2- (O-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl)-
4,5-di (m-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2-
(O-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5
-Diphenylimidazole dimer, 2,4-di (p-methoxyphenyl) -5-phenylimidazole dimer,
2- (2,4-dimethoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole dimer, and 1,7-bis (9 Acridine derivatives such as -acridinyl) heptane;

The amount of component (C) is 0.1 to 10 parts by weight based on 100 parts by weight of the total of components (A) and (B).
Parts by weight are preferred. If the amount is less than 0.1 part by weight, the photosensitivity tends to be insufficient. If the amount exceeds 10 parts by weight, light absorption on the surface of the photosensitive composition during exposure increases, and Tends to be insufficiently photocured.

(D) As the pigment or dye, generally known coloring agents can be used, and the compatibility with the photosensitive resin layer, particularly the ethylenically unsaturated compound or the carboxyl group-containing film-imparting polymer, is targeted. The selection is made in consideration of hue, light transmittance and the like. As a pigment that can be used for a color filter, various compounds can be used.
Examples include inorganic pigments such as barium sulfate, zinc oxide, lead sulfate, titanium oxide, red iron oxide, carbon black, graphite, and chromium oxide, and the following organic pigments (color index numbers).

Yellow pigment: CI Pigment Yellow 20,
24, 83, 86, 93, 109, 110, 117, 1
25, 137, 138, 139, 147, 148, 15
3, 154, 166, 168 Orange pigment: CI Pigment Orange 36, 43, 5
1, 55, 59, 61 Red pigment: CI Pigment Red 9, 97, 122, 1
23, 149, 168, 177, 180, 092, 21
5, 216, 217, 220, 223, 224, 22
6, 227, 228, 240, 48: 1 Violet pigment: CI Pigment Violet 19,
23, 29, 30, 37, 40, 50 Blue pigment: CI Pigment Blue 15, 15: 6, 2,
2, 60, 64 Green pigment: CI Pigment Green 7, 36 Black pigment: CI Pigment Black 7

The amount of the component (D) is preferably 1 to 50 parts by weight based on 100 parts by weight of the total of the components (A) and (B). If the amount is less than 1 part by weight, the coloring tends to be insufficient, and if it exceeds 50 parts by weight, the light transmittance tends to decrease.

In the colored photosensitive resin layer, a melamine resin and / or an epoxy resin which thermally reacts with a carboxyl group of a carboxyl group-containing film-imparting polymer in order to enhance the heat curability are added to the component (A) and the component (B). Total amount of ingredients 10
It is preferable to add 1 to 20 parts by weight to 0 parts by weight and heat the mixture. The heating temperature is preferably from 130 to 200 ° C., and the heating time is preferably from 30 to 60 minutes, from the viewpoint of improving the crosslinking density of the colored layer, improving the heat resistance, and the like.

In the present invention, a step of exposing in a pattern is performed after the photosensitive film is bonded. Although there is no particular limitation on the bonding method, for example, a method of using a laminator and applying pressure by a hot roll or the like can be used. The temperature at the time of bonding is 60-150 ° C
And more preferably 100 to 150 ° C. The pressure at the time of bonding is 1 to 10 kgf / cm
^2, and more preferably 5 to 10 kgf / cm ² . When passing through a hot roll, the passing speed is preferably 0.1 to 5 m / min.
More preferably, it is 1 to 1.5 m / min.

The method of exposing in a pattern is not particularly limited. For example, a negative mask having a predetermined pattern is placed on a base film (or on a photosensitive resin layer when the base film is peeled), and the negative mask is exposed. A method of irradiating an actinic ray with a light source such as an ultra-high pressure mercury lamp from above, and a method of irradiating an actinic ray with a CAD using a laser are exemplified.

After this exposure step, a step of heating to increase the film thickness is performed, and then a development step is performed to form a color pattern (pixel) on the transparent substrate. The developing step is a step of developing the photosensitive resin layer to remove a part (unnecessary part) other than a part desired to be a color pattern (pixel) of the photosensitive resin layer. Although there is no particular limitation on the method of development, for example, a wet development method using a difference in solubility between the exposed portion and the unexposed portion of the photosensitive resin layer caused by the patternwise exposure to a developing solution, an exposed portion and an unexposed portion And a dry developing method utilizing the difference in adhesive force. From the viewpoint of resolution, a wet development method is preferable, and the developer is not particularly limited. Examples thereof include an organic solvent such as 1,1,1, -trichloroethane and an alkaline solution such as an aqueous sodium carbonate solution. . In the wet development method, these developing solutions are brought into contact with the photosensitive resin layer after patternwise exposure, and one of the exposed and unexposed portions is dissolved or removed to remove.

The color filter according to the present invention is manufactured, for example, as follows. First, a colored photosensitive resin layer formed on a photosensitive film is laminated on a transparent substrate, and is exposed in a pattern by, for example, placing a negative mask of a predetermined pattern on a base film on the surface of the colored photosensitive resin layer and exposing the film. After that, the base film is removed, and in the case of a negative photosensitive resin layer, an unexposed portion is removed and developed with a developing solution, and in the case of a positive photosensitive resin layer, the exposed portion is removed with a developing solution and developed. As a result, a colored pattern (pixel) is formed. This colored pattern forming step is repeated a predetermined number of times by using photosensitive films of different colors to form a multicolor pattern, thereby obtaining a color filter.

[0030]

The present invention will be described below by way of examples. Example 1 (1) Production of Coating Liquid for Colored Photosensitive Resin Layer 135 parts by weight of any of the pigment pastes of Table 2 and 200 parts by weight of a solution in which the materials of Table 1 were uniformly dissolved, and melamine resin 5
Parts by weight and 5 parts by weight of a silane coupling agent were added and dissolved and dispersed to obtain a coating liquid for a colored photosensitive resin layer.

[0031]

[Table 1]

[0032]

[Table 2]

Melamine resin Cymel 300 (trade name of hexamethoxymethyl melamine, manufactured by Mitsui Toatsu Chemicals, Inc.) Silane coupling agent KBM503 (Shin-Etsu Chemical Co., Ltd.)
Preparation of Coating Solution The coating solution was dispersed by ultrasonic waves for 2.5 hours immediately before use and adjusted.

(2) Production of photosensitive film The obtained coating solution was coated on a 6 μm-thick polyethylene terephthalate film (Tetron film M5 manufactured by Teijin Co., Ltd.).
R) It was applied to a uniform thickness using a kiss-touch reverse type coating machine, and dried with a dryer at 100 ° C. for 2 minutes.
A 30 μm-thick polyethylene film was laminated as a protective film to obtain a photosensitive film. The thickness of the photosensitive resin layer after drying was 2.0 μm for red, 1.8 μm for blue, and 1.8 μm for green.

(3) Manufacture of a color filter The order of pixel shapes is red, blue and green. (A) Substrate Heating Step A base substrate for color filters (Corning 7054, manufactured by Corning) was heated at 80 ° C. for 10 minutes. (B) Laminating Step While peeling off the protective film of the photosensitive film, a colored photosensitive resin layer was laminated on the base substrate for the color filter under the following conditions. The second and third colors were laminated in parallel to the stripe of the preceding pixel. Roll temperature 120 ° C Roll pressure 6.0 kgf / cm ² Speed 0.5 m / min

(C) Exposure Step A predetermined pattern (ordinary stripe pattern. Finished with a width of 80.0 μm and a length of 150 mm, designed in a cycle of 300 μm so as to repeat in the order of red, green and blue. Exposure was performed by an exposure machine HMW-201B (3 kW, ultrahigh pressure mercury lamp, manufactured by Oak Manufacturing Co., Ltd.) through a negative pattern (negative mask) having a stripe pattern. (D) Heating step Red was not carried out, and blue and green were heated by a dryer at 80 ° C for 15 minutes. (E) Peeling Step The polyethylene terephthalate film was removed.

(F) Development Step A 0.08% by weight aqueous solution of Na ₂ CO _{3 at} 30 ° C. was used as a developer for all colors. Red was developed by spraying for 15 seconds, and the unexposed portions were removed to form a first-color red coloring pattern. Each of blue and green is preliminarily developed by spraying for 5 seconds and washed with pure water to remove the developing solution on the developing surface, and air cleaning is performed.
After drying at 0 ° C. for 5 minutes, development was carried out for blue and green by spraying for 20 seconds to form a second color blue and a third color green coloring pattern.

The steps (a) to (f) of forming a colored pattern were repeated in the order of red, blue and green using photosensitive films of respective colors to form a multicolored pattern. The exposure amount was 50 mJ / cm ² for the red, blue and green photosensitive resin layers. The obtained multicolor pattern was irradiated at 3 J / cm ² using an ultraviolet irradiator (Lamp H5600L / 2, manufactured by Toshiba Denshi Co., Ltd.), and then heated at 150 ° C. for 45 minutes to obtain a color filter. The obtained color filter has red, blue, and green patterns arranged in an orderly manner, and the film thickness is red.
0 μm, 2.0 μm for blue and 2.0 μm for green. There was an increase in the film thickness of 0.2 μm for blue and green respectively.

Example 2 The procedure of Example 1 was repeated, except that the materials shown in Table 3 were used instead of the materials shown in Table 1.

[0040]

[Table 3]

Example 3 In place of the materials in Table 1, the following materials in Table 4 were used. The thickness of the photosensitive resin layer was 1.8 μm for red and blue, and 2.0 μm for green. In the heating step (c), only red and blue were performed, and green was not performed. Other than that, it carried out similarly to Example 1.

[0042]

[Table 4]

The obtained color filters had a thickness of 2.0 μm for both red, green and blue. There was an increase in the film thickness between red and blue, and the step between pixels was 0 μm.

Comparative Example 1 The procedure of Example 1 was repeated, except that the heating step (c) was not carried out for blue and green, and the step of peeling off the base film was carried out. In the obtained color filter, red was 2.0 μm, blue was 1.8 μm, and green was 1.8 μm. No increase in the film thickness was observed, and the film thickness of the coating film was maintained.

[0045]

According to the method for manufacturing a color filter according to the first aspect, the thickness of each color can be adjusted after the photosensitive layer is attached, and a color filter having a small step between pixels and a uniform thickness can be manufactured.

Claims (1)

[Claims] 1. A photosensitive film comprising a base film and a colored photosensitive resin layer on a transparent substrate, (1)
Manufacture of a color filter for forming a multicolor pattern by repeating a step of bonding a colored photosensitive resin layer so as to face the substrate, a step of (2) exposing in a pattern, and a step of (3) a developing step. A method for producing a color filter, comprising, following the step (2), performing a step of increasing the film thickness by heating.