JPH07134206A - Photosensitive film for color filter - Google Patents

Abstract

PURPOSE:To produce a color filter with the surface smoothed and without any picture defect by specifying the average roughness of the surface of a transparent substrate film in contact with a colored photosensitive resin layer. CONSTITUTION:A transparent substrate film, a colored photosensitive resin layer and a protective film are laminated in this order to constitute the photosensitive film for a color filter. The average roughness of the surface of the substrate film in contact with the colored photosensitive resin layer is controlled to be <=0.02mum, and the average roughness of the other surface can be adjusted to be <=0.2mum. The average surface roughness can be easily measured, for example, with a surface roughness meter by direct contact of needle and a laser measuring system. The thickness of the substrate film is preferably controlled to be 2 to 10mum. Further, an ethylenic unsaturated compd., a film property-imparting polymer contg. carboxyl, a photopolymerization initiator and pigment or dye are preferably incorporated into the colored photosensitive resin layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive film for a color filter used in a color liquid crystal display or the like, and more particularly to a photosensitive film for a color filter which can provide a color filter having a smooth surface.

[0002]

2. Description of the Related Art A color filter is an optically transparent substrate, such as glass, having two or more kinds of very fine stripe-like or mosaic-like patterns having different hues, which are parallel or parallel to each other at regular intervals. It is a crossed arrangement. It is necessary for these patterns to arrange hues in a predetermined order at predetermined intervals and to form a uniform layer with little thickness unevenness, and various methods for manufacturing color filters have been proposed. For example, the screen printing method can form a low-cost color filter. Further, there is a method using a photolithography technique, that is, a method of irradiating a transparent film formed on a color filter substrate with ultraviolet rays through a predetermined negative mask to remove an unexposed portion, and then dyeing while forming a stain-proof layer. is there.

As an improved method of the above-mentioned method, a colored solution type photosensitive resin composition is applied on a substrate and dried,
There is a method of forming a color filter by exposing and developing to form a pattern of one color and repeating this step for other colors in the same manner. In addition, multicolor fine stripes using a transparent support film and a photosensitive film composed of a photosensitive resin layer, which are generally used for etching resists, plating resists, solder resists, etc. at the time of manufacturing printed wiring boards, or There is known a method of manufacturing a color filter that can easily and accurately form a mosaic pattern.

A step of adhering a photosensitive film composed of a support film and a photosensitive resin layer colored in one color on a transparent substrate so that the colored photosensitive resin layer faces the substrate, is exposed to light and is predetermined. The step of forming a pattern and the step of peeling and developing the support film are repeated to form a multicolor pattern, thereby manufacturing a color filter.

For example, a layer of a photosensitive resin containing one hue colorant is applied to a transparent support film and dried, and the layer of the photosensitive resin of the photosensitive film is transferred onto a transparent plate to obtain a predetermined pattern. A method of forming a pattern by exposing and developing through a mask (Japanese Patent Laid-Open No. 61-99102) is known. Also, after exposing and developing this film through a mask of a predetermined pattern to form a pattern,
A method of forming a color filter pattern by transferring onto a transparent plate (Japanese Patent Laid-Open No. 61-99103), and heat-pressing this film onto the transparent plate through a mask having a predetermined pattern. A method is known in which a support film is exposed, exposed, and developed to form a transparent colored image pattern (JP-A-63-187203).
Further, a photosensitive film having a polyvinyl acetate copolymer adhesive on a colored photosensitive resin is used.
A method of forming a color filter pattern by the same method as in Japanese Patent No. 187203 (Japanese Patent Laid-Open No. 24-24624)
It has been known.

However, a conventional transparent support film having an average surface roughness of 0.05 μm for producing a printed wiring board is used to prepare a photosensitive film for a color filter, which is further used to form a color filter. When manufactured,
A large number of irregularities are formed on the surface, and there is a problem that uneven coating of an overcoat layer made of a transparent resin in a subsequent step and unevenness in the formation of an In ₂ O ₃ —SnO ₂ system electrode due to subsequent sputtering occur. Also, large irregularities directly appear as image defects (the surface average roughness of the color filter in which image defects appear is 0.05 μm).

[0007]

SUMMARY OF THE INVENTION The present invention solves the above problems and provides a photosensitive film for a color filter which is capable of producing a color filter having a smooth surface and no image defects.

[0008]

The present invention provides a photosensitive film for a color filter in which (a) a transparent support film, (b) a colored photosensitive resin layer and (c) a protective film are laminated in this order, (A) A photosensitive film for a color filter, wherein (b) the surface of the transparent support film which comes into contact with the colored photosensitive resin layer has an average surface roughness of 0.02 μm or less.

The transparent support film (a) in the present invention is required to have an average surface roughness of 0.02 μm or less on the surface in contact with the (b) colored photosensitive resin layer.
The average surface roughness of the other surface of the transparent support film may be 0.02 μm or less. The average surface roughness can be easily measured with a surface roughness meter such as a direct contact type of a needle or a laser measuring type.

Examples of these transparent support films having an average surface roughness of 0.02 μm or less include Tetron film GS series and M5R series polyester films manufactured by Teijin Limited, and Mylar film D series polyester films manufactured by DuPont. Is mentioned.

The thickness of the transparent support film is 2 to 10 μm.
It is preferably m. If it is less than 2 μm, it tends to be difficult to manufacture a photosensitive film, and if it is more than 10 μm, it may be difficult to manufacture pixels already formed at the time of manufacturing a color filter, that is, for the first and second colors in the case of red, blue and green. Poor followability tends to result in pixel defects.

The colored photosensitive resin layer contains an ethylenically unsaturated compound (A), a carboxyl group-containing film-forming polymer (B), a photopolymerization initiator (C) and a pigment or dye (D). Is preferable, and the layer thickness is 0.5 to 5
It is preferably set to μm.

The ethylenically unsaturated compound ((A) component) is, for example, a compound obtained by adding an α, β-unsaturated carboxylic acid to a polyhydric alcohol, for example, trimethylolpropane di (meth) acrylate (methacrylate). Or acrylate, the same shall apply hereinafter), trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc .; glycidyl group-containing A compound obtained by adding an α, β-unsaturated carboxylic acid to the compound, for example, trimethylolpropane triglycidyl ether triacrylate, bisphenol A diglycidyl ether di (meth) acrylate; a polyvalent carboxylic acid, for example, anhydrous Compounds with Tal acid and a hydroxyl group and an ethylenically unsaturated group, ester of example β- hydroxyethyl (meth) acrylate; (meth)
Alkyl ester of acrylic acid (meaning methacrylic acid or acrylic acid, the same applies hereinafter), for example, methyl (meth) acrylate, ethyl (meth) acrylate, (meth)
Examples thereof include butyl acrylate and 2-ethylhexyl (meth) acrylate, and urethane diacrylate compounds obtained by reacting trimethylhexamethylene diisocyanate with a dihydric alcohol and a divalent (meth) acrylic acid monoester. Is also used. You may use 2 or more types of these compounds. The compounding amount of the component (A) is preferably 90 with the total amount of the component (A) and the component (B) being 100 parts by weight.
˜50 parts by weight.

Examples of the carboxyl group-containing film-forming polymer (component (B)) include, for example, a copolymer of (meth) acrylic acid alkyl ester and (meth) acrylic acid:
Examples thereof include copolymers of (meth) acrylic acid alkyl ester, (meth) acrylic acid, and a vinyl monomer copolymerizable therewith. Examples of alkyl (meth) acrylates include methyl (meth) acrylate, (meth)
Examples thereof include ethyl acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. Further, as vinyl monomers copolymerizable with (meth) acrylic acid alkyl ester and (meth) acrylic acid, dimethylethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, diethyl (meth) acrylate 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, acrylamide, diacetone acrylamide, styrene, vinyltoluene and the like. Furthermore, polyesters such as terephthalic acid, isophthalic acid and sebacic acid containing (meth) acrylic acid as a copolymerization component, copolymers of butadiene and acrylonitrile, cellulose acetate, cellulose acetate butyrate,
Methyl cellulose, ethyl cellulose and the like can also be used.

By using the component (B), the coating properties and the film properties of the cured product are improved, and the blending amounts are the components (A) and (B).
The total amount of the components is 100 parts by weight, and preferably 10 to 50.
Parts by weight. If the blending amount is less than 10 parts by weight, the amount of ethylenically unsaturated compound increases, and the photosensitivity decreases, and if it exceeds 50 parts by weight, the photocured product tends to become brittle. Further, the weight average molecular weight of the component (B) is preferably 10,000 or more from the viewpoint of the coating property and the film strength.

Examples of the photopolymerization initiator (component (C)) include benzophenone, N, N'-tetramethyl-
4,4'-diaminobenzophenone (Michler's ketone), N, N'-tetramethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 4,4'-diethylaminobenzophenone, 2-ethylanthraquinone , Aromatic ketones such as phenanthrenequinone; benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether; benzoins such as methylbenzoin and ethylbenzoin; 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 Body, 2, 4
-Di (p-methoxyphenyl) -5-phenylimidazole dimer, 2- (2,4-dimethoxyphenyl)-
A 2,4,5-triarylimidazole dimer such as 4,5-diphenylimidazole dimer or 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole dimer is used.

The blending amounts of the component (C) are the components (A) and (B).
The total amount of the components is preferably 0.1 to 1 with respect to 100 parts by weight.
0 parts by weight. If the content is less than 0.1 parts by weight, the photosensitivity will be insufficient, and if it exceeds 10 parts by weight, the light absorption on the surface of the composition will increase during exposure, and the internal photocuring will tend to be insufficient. There is.

As the above-mentioned pigment or dye (component (D)), known colorants can be used, and the compatibility with the components of the photosensitive resin layer, especially the compatibility with the ethylenically unsaturated compound or the carboxyl group-containing film-forming polymer. Is selected in consideration of the hue, the light transmittance, and the like. The compounding amount of the component (D) is preferably 1 to 50 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B). If the blending amount is less than 1 part by weight, coloring tends to be inadequate.
If it exceeds the weight part, the light transmittance tends to decrease.

In the colored photosensitive resin layer, a melamine resin and / or an epoxy resin which thermally reacts with the carboxyl group of the carboxyl group-containing film-forming polymer (B) in order to enhance the heat curability, and (A) component ( It is preferable to add 1 to 20 parts by weight to 100 parts by weight of the total amount of component B). Add these to 130 ~ 200 ℃
By heating for 30 to 60 minutes, the crosslink density is improved and the heat resistance is significantly improved.

As the protective film (C) in the present invention, for example, a polyester film, a polyolefin film and the like are used, but from the viewpoint of price, flexibility, strength, hardness and the like, a polyolefin film, especially a polyethylene film is preferable. The thickness is 1.0 to 4
The thickness is preferably 0 μm, and if it is less than 10 μm, the handling property tends to be poor, and if it exceeds 40 μm, the cost tends to increase.

In the present invention, the color filter is manufactured as follows. First, a colored photosensitive resin layer was laminated (bonded) on a transparent substrate while the protective film was peeled off, and a negative mask having a predetermined pattern was placed on the transparent support film on the surface of the colored photosensitive resin layer for exposure. Then, the transparent support film is removed. Then, the unexposed portion is developed with a developing solution to form a colored pattern. This colored pattern forming step is repeated a predetermined number of times using photosensitive films of different colors to form a pattern of another color to obtain a color filter.

The laminating step is performed while the photosensitive resin layer is heated and softened by a heatable roll generally called a hot roll or a heating jacket called a heat shoe and a roll called a laminating roll.

The exposure process generally has a dedicated exposure device,
Use a contact or non-contact type. As the lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a xenon lamp lamp, or the like that effectively radiates ultraviolet rays can be used.

The developing method includes a dipping method, a spray method and the like, and the high pressure spray method is most suitable for achieving high resolution. The developing solution is greatly different between the solvent developing type and the alkali developing type. In the solvent developing type, 1,1,1-trichloroethane,
In the alkali development type, it is common to use 1% by weight of sodium carbonate.

When the photosensitive film for a color filter of the present invention is used, since the transparent support film has an average surface roughness of 0.02 μm or less, the surface of the transferred colored photosensitive resin layer also has an average surface. A smooth surface having a roughness of 0.02 μm or less can be obtained, defects in subsequent steps can be greatly reduced, and image defects can be eliminated.

[0026]

EXAMPLES Next, the present invention will be described in detail with reference to Examples.

Examples 1 and 2 and Comparative Examples 1 and 2 To 211 parts by weight of a solution prepared by uniformly dissolving the materials shown in Table 1, 35 parts by weight of any of the pigments shown in Table 2 was added and dissolved to give a photosensitive material. A resin layer coating solution was obtained.

[0028]

[Table 1]

[0029]

[Table 2]

Then, this solution was uniformly coated on various polyethylene terephthalate films (transparent support film (a)) shown in Table 3 and dried by a hot air convection dryer at 100 ° C. for about 10 minutes to be colored. Photosensitive resin layer (b)
After forming, a polyethylene film having a thickness of 30 μm was laminated as a protective film (c) to obtain a photosensitive film for a color filter. The film thickness of the colored photosensitive resin layer after drying was 1.8 μm.

Next, the base substrate for the color filter is
After heating at 50 ° C. for 10 minutes, the colored photosensitive resin layer was laminated at a roll temperature of 150 ° C., a roll pressure of 6 kg / cm ² , and a speed of 1.0 m / min while peeling off the protective film of the color filter photosensitive film. . Then, the exposure machine HMW-201B (3kW,
After exposure with an ultra-high pressure mercury lamp (Oak Seisakusho), the polyethylene terephthalate film was removed, and the film was removed at 30 ° C. to 0.
Spray development was carried out for 10 to 20 seconds with a 05% by weight Na ₂ CO ₃ aqueous solution to remove the unexposed portion and form a colored pattern of one color. This step of forming a colored pattern was repeated three times using the photosensitive films of each color in the order of red, blue and green to form the multicolor pattern shown in FIG.

The exposure dose at this time was 200 mJ / cm ² .
The obtained multicolor pattern was heated at 150 ° C. for 45 minutes to obtain a color filter. The appearance of the obtained color filter was visually observed to check for defects. In addition, the average surface roughness of the transparent support film and the color filter was measured (as a surface roughness meter, manufactured by Kosaka Seisakusho, trade name Surf Coder 3).
(Measured at a magnification of 10000 times using 0D), and the results are shown in Table 3 together. In the case of using the support film having an average surface roughness of 0.02 μm or less, the average surface roughness of the pixels of the color filter also showed a good value of 0.02 μm or less.

[0033]

[Table 3]

[0034]

By using the photosensitive film for a color filter of the present invention, a color filter having a smooth surface and no image defects can be easily manufactured with good workability.

Claims (2)

[Claims] 1. A photosensitive film for a color filter, in which (a) a transparent support film, (b) a colored photosensitive resin layer and (c) a protective film are laminated in this order,
A photosensitive film for a color filter, wherein (a) the transparent support film (b) has an average surface roughness of 0.02 μm or less on the surface in contact with the colored photosensitive resin layer. 2. The thickness of (a) the transparent support film is 2 to
The photosensitive film for a color filter according to claim 1, which has a thickness of 10 μm.