JP2010117481A - Color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter in which adhesion between a colored layer formed by a color resist having a high pigment concentration and an overcoat film is sufficient, and which has excellent ITO resistance, high light transmittance and satisfactory flatness. <P>SOLUTION: Regarding the color filter in which the surface of a colored layer (30) is disposed with an overcoat film (40) obtained by hard-filming a photosensitive composition for an overcoat film at least composed of a binder resin (A), a compound (B) having an ethylenic unsaturated bond and a photopolymerization initiator (C) on a transparent substrate (10), the overcoat film is a hard film matter of the photosensitive composition for an overcoat film in which the mass ratio of the solid content of the compound (B) having an ethylenic unsaturated bond to the mass of the solid content of the binder resin (A) is ≥0.6 and ≤1.0, and further, the Vickers hardness of the overcoat film is ≥50 and ≤65. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a color filter used for a color liquid crystal display device, and more particularly to a color filter in which an overcoat film (protective film, planarizing film) is disposed on a colored layer.

  Color liquid crystal display devices are used in various products such as personal computers, monitors, televisions, and mobile phones, and are rapidly spreading. A color filter is an indispensable component for color display of a liquid crystal display device. In recent years, the liquid crystal display device has been improved in image quality, and those having high color reproducibility, a wide viewing angle, and high-speed response have appeared. Along with this, the required performance for the color filters included in these liquid crystal display devices has been advanced, and higher color purity, higher contrast, improved flatness, and the like are required.

  With regard to the improvement in flatness, there is an aim of reducing the alignment disorder of the liquid crystal by flattening the unevenness of the color filter surface and improving the contrast as the liquid crystal panel. In order to impart flatness, an overcoat film (flattening film, protective film) is generally formed on a black matrix or a colored layer. In addition to various resistances, such an overcoat film has an adhesive property with a colored layer or a black matrix as a base material, and a transparent electrode layer deposited on the overcoat film from the viewpoint of reliability. There are demands for good adhesion, excellent ability to flatten the unevenness of the colored layer, and good transparency so as not to lower the image quality improvement performance of the liquid crystal display device. .

  As a material for forming an overcoat film having the above characteristics and excellent flatness, Patent Document 1 includes a polymerizable unsaturated compound having an oxiranyl group or an oxetanyl group, and one or more hydroxyl groups. A thermosetting resin composition is disclosed, and Patent Document 2 discloses an average molecular weight of 1,200 or less in which an alkali-soluble polymer having a mass average molecular weight of 3,000 to 50,000 and an ethylenically unsaturated compound are mixed. A photocurable resin composition containing a resin composition and a polymerization initiator and a color filter using the same are disclosed.

  In addition, for color resists corresponding to the above-mentioned required characteristics, when pigment particles are miniaturized for high contrast, the coloring power decreases with the miniaturization. It is necessary to increase the pigment concentration. Even in the case of increasing the color purity, it is necessary to increase the pigment concentration in the color resist composition in consideration of the restrictions on the structure of the liquid crystal panel and the productivity when forming the colored layer in order to realize a deep color. When using a colored layer formed of a color resist having a high pigment concentration, the adhesion between the overcoat film and the colored layer, which was not a problem with the conventional colored layer, may not be sufficient.

Here, as one of the means for improving the adhesion between the overcoat film and the colored layer, there is a reduction in the crosslinking density due to the blending of the low molecular weight compound in the resin composition forming the overcoat film. However, in such a resin composition, wrinkles may occur due to a decrease in flatness caused by a decrease in the thickness of the coating film by heat treatment or exposure to a high temperature during the formation of the transparent electrode. Hereinafter, resistance to wrinkle generation when forming a transparent electrode is abbreviated as ITO resistance.
JP 2008-31417 A Japanese Patent Laid-Open No. 2007-3866

  The present invention has been made in view of the above-described problems. In a color filter having an overcoat film disposed on a colored layer, which is used in a color liquid crystal display device or the like, a color formed by a color resist having a high pigment concentration. It is an object of the present invention to provide a color filter having sufficient adhesion between a layer and an overcoat film, excellent ITO resistance, high light transmittance, and good flatness.

  The invention according to claim 1 of the present invention is a photosensitivity for overcoat film comprising at least (A) a binder resin, (B) a compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator on a transparent substrate. In a color filter in which an overcoat film formed by hardening a composition is disposed on a colored layer, the overcoat film has (B) an ethylenically unsaturated bond relative to the mass of (A) the binder resin solid content. The solid content of the compound is a hard film of the photosensitive composition for an overcoat film having a mass ratio of 0.6 or more and 1.0 or less, and the Vickers hardness of the overcoat film is 50 or more and 65 or less. This is a characteristic color filter.

  Further, the invention according to claim 2 of the present invention is the color filter according to claim 1, wherein the overcoat film has a light transmittance of 90% or more in a visible region of 400 nm to 700 nm. .

  Further, in the invention according to claim 3 of the present invention, the step of the surface of the color filter after the overcoat film is disposed is less than 0.3 μm. It is.

  In the invention according to claim 4 of the present invention, the color of the overcoat film according to any one of claims 1 to 3, wherein the film thickness of the overcoat film is 1.0 μm or more and 5.0 μm or less. It is a filter.

  The color filter of the present invention defines the mass ratio of (A) the binder resin and (B) the compound having an ethylenically unsaturated bond in a certain range in the photosensitive resin composition forming the overcoat film, and Since the Vickers hardness of the overcoat film is 50 to 65, the adhesion between the colored layer formed of the color resist having a high pigment concentration and the overcoat film is sufficient, the ITO resistance is excellent, the light transmittance is high, and the flatness A color filter with good properties can be obtained.

  The color filter of the present invention will be described below based on an embodiment.

  The present inventors have formed a black matrix and a colored layer on a transparent substrate, provided an overcoat film on the black matrix and the colored layer, and the transparent electrode layer is formed on the colored layer through the overcoat film. In the color filter provided in the above, it was found that wrinkles during the ITO film formation did not occur in the overcoat film having a film hardness represented by Vickers hardness of 50 or more. If the film hardness is 50 or less, wrinkles will occur during ITO film formation. The higher the film hardness is, the more the ITO wrinkle is suppressed, but the adhesiveness with the colored layer is lowered. Therefore, the optimum range of Vickers hardness is 50 or more and 65 or less, and particularly preferably 50 or more and 63 or less.

  Further, in the photosensitive resin composition forming the overcoat film, the mass ratio of (B) the compound having an ethylenically unsaturated bond to (A) the binder resin (solid content mass of (B) / (A) It has been found that when the solid content (mass content) is 0.6 or more and 1.0 or less, an overcoat film having good adhesion to the colored layer, ITO resistance, and flatness is obtained. The lower the ratio, the better the adhesion, but ITO wrinkles are more likely to occur because the crosslinking component for the binder resin is reduced. Further, when this ratio is lowered, the average molecular weight in the composition is increased, resulting in a problem that flatness is lowered. When this ratio increases, the flatness tends to improve, but the adhesion decreases.

  Examples of the (A) binder resin in the overcoat film photosensitive composition according to the present invention include acrylic resins and novolak resins. An example of the acrylic resin includes a copolymer containing an acid anhydride such as phthalic anhydride having at least one carboxylic acid in the molecule. In particular, those using acrylic acid or methacrylic acid are preferred in terms of sensitivity.

  In order to adjust other properties, a ternary or higher multi-component copolymer may be used by using a third component comonomer. Such comonomers include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, ethoxyethyl methacrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, benzyl acrylate , Methyl acrylate, ethyl acrylate, butyl acrylate, hydroxymethyl acrylate, cyclohexyl acrylate, vinyl acetate, tetrahydrofurfuryl acrylate, N-vinylpyrrolidone, propyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, etc. But not limited to this, it can be copolymerized if used.

  Moreover, you may use the copolymer containing the monomer which has N-substituted maleimide and an acidic functional group. N-substituted maleimides include cyclohexylmaleimide, phenylmaleimide, methylmaleimide, ethylmaleimide, n-butylmaleimide, laurylmaleimide and the like. Of these, cyclohexylmaleimide or phenylmaleimide is particularly preferable because of its good adhesion to a transparent substrate and developability.

  Furthermore, as an example of a novolak resin, after adding a carboxylic acid-containing compound such as acrylic acid to a phenol novolak epoxy resin, a cresol novolak epoxy resin, etc., an acid anhydride is added to give an acid value. However, the present invention is not limited to these examples.

  Next, as the compound (B) having an ethylenically unsaturated bond, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, Tetramethylene glycol di (meth) acrylate, dicyclopentanyl diacrylate, EO (ethylene oxide) modified bisphenol A dimethacrylate, methoxylated cyclohexyl diacrylate, caprolactone modified hydroxypivalic acid neopentyl glycol diacrylate, neopentyl glycol modified trimethylol Propane diacrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, glycero (Meth) the (meth) acrylic acid esters of acrylates such as, but not necessarily limited thereto. These can be used alone or in combination of two or more.

Next, as (C) photopolymerization initiator, for example, acetophenone, 2,2′-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, dichloroacetophenone, trichloroacetophenone, p-tert-butyl Acetophenones such as acetophenone, benzophenone, 2-chlorobenzophenone, benzophenones such as p, p'-bisdimethylaminobenzophenone, benzoin ethers such as benzyl, benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyldimethyl Sulfur compounds such as ketal, thioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone Anthraquinones such as 2-ethylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-diphenylanthraquinone, 2,4-trichloromethyl- (4′-methoxyphenyl) -6-triazine, 2,4 -Trichloromethyl- (4'-methoxynaphthyl) -6-triazine, 2,4-trichloromethyl- (piperonyl) -6-triazine, 2,4-trichloromethyl- (4'-methoxystyryl) -6-triazine, etc. Triazines, organic peroxides such as azobisisobutyronitrile, benzoyl peroxide, cumene peroxide, thiol compounds such as 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, etc. But not necessarily limited to these Not. These photopolymerization initiators can be used alone or in combination of two or more.

  Moreover, the photosensitive composition for overcoat films according to the present invention may contain a known solvent, a known additive, or a thermosetting resin such as an epoxy resin or a melamine resin, if necessary. Examples of the solvent include cyclohexanone and propylene glycol monomethyl ether acetate, but are not necessarily limited thereto. When the solvent is used, the blending amount (% by mass) of the solvent is not particularly limited, but is preferably 50 to 1,000%, more preferably 200 to 100% based on the mass of the solid content of the photocurable resin composition. 800%.

  Others, for example, thermal polymerization inhibitors, inorganic pigments, silane coupling agents, dyes, fluorescent brighteners, yellowing inhibitors, antioxidants, antifoaming agents, deodorants, fragrances, bactericides, antibacterial agents In addition, a fungicide solvent or the like can be used as necessary.

  An embodiment of the color filter of the present invention will be specifically described with reference to the drawings. FIG. 1 is a schematic view showing an example of the color filter of the present invention in cross section. The color filter of the present invention comprises a black matrix (20) and a colored layer (30) formed on a transparent substrate (10), and is overcoated with the photocurable resin composition according to the present invention at a predetermined position thereof. A film (40) is formed, and a transparent electrode layer (50) serving as a common electrode is provided thereon.

  As the transparent substrate (10) constituting the color filter, glass, a plastic plate, a film, or the like can be used. In recent years, plastic substrates having excellent permeability and chemical resistance have been proposed, but generally alkali-free glass having a low coefficient of thermal expansion and excellent dimensional accuracy at high temperatures is widely used.

  The black matrix (20) provided on the transparent substrate (10) is provided between the pixels of each color and outside the colored layer (30) forming region for the purpose of preventing a decrease in contrast due to light leakage. Such a black matrix is formed by patterning a multilayer vapor-deposited thin film of chromium or chromium oxide, or by using a photosensitive resin in which light-shielding fine particles such as carbon black and metal oxide are dispersed, and by a normal photolithography method. It can be created by a method of forming.

The colored pixels used in the color filter of the present invention are not particularly limited as long as they are necessary for color display, and can be used in combination with appropriate ones. Each color pixel can be formed into a predetermined pattern shape by photolithography using a pigment dispersion resist. That is, a photosensitive composition containing a pigment adjusted to express a desired color is applied on a transparent substrate, and pattern exposure and development are performed to form a first color pixel. By repeating this for a predetermined number of colors, it is possible to obtain a target colored pixel. In addition to the above method, a printing method, an inkjet method, a transfer method, or a method including the above-described photolithography method may be combined.

  The overcoat film in the color filter of the present invention has a function of reducing surface steps of the color filter as a flattening film and improving various resistances such as chemical resistance and heat resistance as a protective film for the colored layer. . Such an overcoat film can be formed by using a photosensitive resin or a thermosetting resin, applying a coating solution containing any of these resins, drying, UV irradiation, or heating. When using a photosensitive resin, there exists an advantage that it can form in a desired pattern shape by carrying out pattern exposure of the coating film.

  For the development when the overcoat film is formed by the photolithography method, an organic solvent may be used, but it is preferable to use water or an alkaline aqueous solution in consideration of the environment. However, since the hydrophilicity of the resin used in water development is high, for example, the optical path difference adjusting layer produced at the same time as the overcoat film has a drawback that the water resistance is weak. Therefore, development is generally performed with an aqueous alkali solution, and a resin and a photocurable material composition suitable for the development are generally used.

  As the alkaline aqueous solution, for example, an aqueous solution of an inorganic salt such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate or potassium carbonate, or an aqueous solution of an organic salt such as hydroxytetramethylammonium or hydroxytetraethylammonium can be used. . You may use these individually or in combination of 2 or more types. In addition, such an alkali-developable photo-curable material is generally composed of an alkali-soluble resin, an ethylenically unsaturated compound, and a polymerization initiator as a main component, and, if necessary, a leveling agent, a solvent, a chain transfer agent, It can be prepared by adding additives such as a polymerization inhibitor and a viscosity modifier.

  As the film thickness when the overcoat film is formed on the color filter, a film thickness in the range of 1.0 μm or more and 5.0 μm or less can be optimally used. When the thickness is 1.0 μm or less, the level difference between the color filter made of the black matrix and the colored layer cannot be sufficiently reduced. Moreover, when the film thickness is 5.0 μm or more, it is difficult to apply the coating film with good uniformity.

  Next, the transparent electrode film controls the behavior of the liquid crystal sandwiched between the substrates by transmitting an electrical signal. In a liquid crystal display device in which liquid crystal is sandwiched between opposing substrates, it is an essential configuration for at least one of a color filter substrate and a TFT array substrate. The transparent electrode film is made of a material that is transparent and conductive and can be formed into a thin film. Usually, an ITO (indium and tin composite oxide) film is used, and IZO (indium and zinc composite oxide) or SnO2 is used. A (tin dioxide) film or the like is selected, and each film can be formed by a general film forming method such as a sputtering method, a PVD method such as a vacuum evaporation method, or a CVD method.

  Hereinafter, specific examples of the present invention will be described.

<Example 1>
[(A) Synthesis of Binder Resin (1)]
In a five-necked reaction vessel with an internal volume of 2 liters, 800 g of propylene glycol monomethyl ether acetate (PGMAc), 100 g of benzyl methacrylate (BzMA), 46 g of butyl methacrylate (BMA), 26 g of methacrylic acid (MAA), hydroxyethyl methacrylate (HEMA) ) 28 g and azobisisobutyronitrile (AIBN) 4 g were added and heated at 80 ° C. for 6 hours while blowing nitrogen to obtain (A) a binder resin (1) solution.
[Preparation of photosensitive resin composition (1) for overcoat film]
100 parts by mass of (A) binder resin (1), 100 parts by mass of (B) ethylenically unsaturated compound: KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.), 8.4 parts by mass of (C) ) Photopolymerization initiator: Irgacure 907 (manufactured by Ciba Specialty Chemicals) was diluted with cyclohexanone so that the solid content in the resist was 30% by mass, and (A) relative to the mass of the binder resin solid content (B) The photosensitive composition (1) for protective films in which the mass ratio of the solid content of the ethylenically unsaturated compound was 1.0 was prepared.

[Preparation of each color pigment dispersion resist]
The following were used as colorants for coloring each color pigment dispersion resist used for forming the colored layer of the color filter.
-Red pigment: C.I. I. Pigment Red 254 (“Ilgar Forred B-CF” manufactured by Ciba Specialty Chemicals), and C.I. I. Pigment Red 177 (“Chromophthal Red A2B” manufactured by Ciba Specialty Chemicals)
Green pigment: C.I. I. Pigment Green 36 (“Lionol Green 6YK” manufactured by Toyo Ink Co., Ltd.), and C.I. I. Pigment Yellow 150 (Bayer's “Funcheon First Yellow Y-5688”)
Blue pigment: C.I. I. Pigment Blue 15 (“Rionol Blue ES” manufactured by Toyo Ink Co., Ltd.), and C.I. I. Pigment Violet 23 (manufactured by BASF “Paliogen Violet 5890”)
[Preparation of red pigment dispersion resist]
-Red pigment dispersion After uniformly stirring and mixing a mixture having the following composition, the mixture was dispersed in a sand mill for 5 hours using a glass bead having a diameter of 1 mm, and then filtered through a 5 m filter to obtain a red pigment dispersion.
Red pigment: C.I. I. Pigment Red 254 18 parts by mass red pigment: C.I. I. Pigment Red 177 2 parts by mass acrylic varnish (solid content 20%) 108 parts by mass / red pigment dispersion resist Thereafter, a mixture of the following composition was stirred and mixed to be uniform, and then filtered through a 5 μm filter to obtain a red pigment dispersion resist. Got.
150 parts by mass of the red pigment dispersion 13 parts by mass of trimethylolpropane triacrylate (“NK ESTER ATMPT” manufactured by Shin-Nakamura Chemical Co., Ltd.)
Photopolymerization initiator 3 parts by mass (“Irgacure 907” manufactured by Ciba Specialty Chemicals)
Sensitizer (“EAB-F” manufactured by Hodogaya Chemical Co., Ltd.) 1 part by mass cyclohexanone 253 parts by mass [Preparation of green pigment-dispersed resist]
-The green pigment dispersion was prepared in the same manner as the red dispersion so that the composition was as follows.
Green pigment: C.I. I. Pigment Green 36 16 parts by mass yellow pigment: C.I. I. Pigment Yellow 150 8 parts by mass acrylic varnish (solid content 20%) 102 parts by mass green pigment dispersion resist Thereafter, a mixture of the following composition is stirred and mixed to be uniform, and then filtered through a 5 μm filter to obtain a green pigment dispersion resist. Got.
150 parts by mass of the green pigment dispersion 14 parts by mass of trimethylolpropane triacrylate (“NK ESTER ATMPT” manufactured by Shin-Nakamura Chemical Co., Ltd.)
Photopolymerization initiator 4 parts by mass (“Irgacure 907” manufactured by Ciba Specialty Chemicals)
Sensitizer ("EAB-F" manufactured by Hodogaya Chemical Co., Ltd.) 2 parts by mass cyclohexanone 257 parts by mass [Preparation of blue pigment dispersion resist]
-Prepared by the same method as the red dispersion so that each of the blue pigment dispersions had the following composition.
Blue pigment: C.I. I. Pigment Blue 15 50 mass parts purple pigment: C.I. I. Pigment Violet 23 2 parts by weight dispersant (“Sols Birds 20000” manufactured by Zeneca) 6 parts by weight acrylic varnish (solid content 20%) 200 parts by weight / blue pigment dispersion resist Thereafter, a mixture having the following composition was stirred and mixed to be uniform. Thereafter, the mixture was filtered through a 5 μm filter to obtain a blue pigment dispersion resist.
150 parts by mass of the blue pigment dispersion 19 parts by mass of trimethylolpropane triacrylate (“NK ester ATMPT” manufactured by Shin-Nakamura Chemical Co., Ltd.)
Photopolymerization initiator 4 parts by mass (“Irgacure 907” manufactured by Ciba Specialty Chemicals)
Sensitizer ("EAB-F" manufactured by Hodogaya Chemical Co., Ltd.) 2 parts by mass cyclohexanone 214 parts by mass [preparation of color filter]
A colored layer was formed using each of the obtained color pigment dispersion resists.
In Example 1, a red pigment dispersion resist was applied to a glass substrate by spin coating so that the finished film thickness was 1.8 μm. After drying at 90 ° C. for 5 minutes, light from a high-pressure mercury lamp was irradiated through a striped photomask for forming a colored layer at 300 mJ / cm ² and developed with an alkali developer for 60 seconds. Then, it baked at 230 degreeC for 30 minutes.

  Next, the green pigment dispersion resist was similarly applied by spin coating so that the finished film thickness was 1.8 μm. After drying at 90 ° C. for 5 minutes, green pixels were obtained by exposing and developing through a photomask so that a pattern was formed adjacent to the red pixels. Then, it baked at 230 degreeC for 30 minutes.

  Further, in the same manner as for red and green, a blue pixel dispersed resist having a finished film thickness of 1.8 μm and adjacent to the red and green pixels was obtained. Then, it baked at 230 degreeC for 30 minutes. As a result, a colored layer composed of striped colored pixels of three colors of red, green, and blue was obtained on the glass substrate.

The alkaline developer has the following composition.
Sodium carbonate 1.5% by mass
Sodium bicarbonate 0.5% by mass
Anionic surfactant (Kao Perillex NBL) 8.0% by mass
90.0% by mass of water
The above-described photosensitive composition for overcoat film (1) was spin-coated on the glass substrate on which the above-mentioned colored layer was formed so as to have a film thickness of 1.5 μm, and dried at 90 ° C. for 5 minutes. 150 mJ / cm ^{2 was} irradiated with light from a high-pressure mercury lamp through a photomask for forming an overcoat. In addition, it exposed with the space | interval (exposure gap) of a photomask and a glass substrate being 100 micrometers. Then, it developed using the developing solution similar to preparation of the above-mentioned colored layer. After washing with water,
An overcoat film was formed on the colored layer by baking at 230 ° C. for 30 minutes. Further, an ITO film was formed thereon as a transparent electrode layer so as to have a thickness of 150 nm by a sputtering method, and the color filter of the present invention of Example 1 was obtained.

<Example 2>
[(A) Synthesis of Binder Resin (2)]
In a five-necked reaction vessel with an internal volume of 2 liters, 800 g of propylene glycol monomethyl ether acetate (PGMAc), 100 g of cyclohexyl methacrylate (CHMA), 46 g of methacrylic acid (MAA), 30 g of hydroxyethyl methacrylate (HEMA), methyl meta 24 g of acrylate (MMA) and 4 g of azobisisobutyronitrile (AIBN) were added and heated at 80 ° C. for 6 hours while blowing nitrogen to obtain a (A) binder resin (2) solution.

[Preparation of photosensitive composition for overcoat film (2)]
100 parts by mass of (A) binder resin (2), 60 parts by mass of (B) ethylenically unsaturated compound: KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.), 8.4 parts by mass of (C) ) Photopolymerization initiator: Irgacure 907 (manufactured by Ciba Specialty Chemicals) was diluted with cyclohexanone so that the solid content in the resist was 30% by mass, and (A) relative to the mass of the binder resin solid content (B) The photosensitive composition (2) for protective films in which the mass ratio of the solid content of the ethylenically unsaturated compound was 0.6 was prepared.

  Using the overcoat film photosensitive composition (2), an overcoat film was formed on the colored layer in the same manner as in Example 1 to obtain the color filter of the present invention of Example 2.

<Comparative Example 1>
[Preparation of photosensitive composition for overcoat film (3)]
100 parts by mass of (A) binder resin (1), 150 parts by mass of (B) ethylenically unsaturated compound: KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.), 8.4 parts by mass of (C) ) Photopolymerization initiator: Irgacure 907 (manufactured by Ciba Specialty Chemicals) was diluted with cyclohexanone so that the solid content in the resist was 30% by mass, and (A) relative to the mass of the binder resin solid content (B) The photosensitive composition (3) for protective films in which the mass ratio of the solid content of the ethylenically unsaturated compound was 1.5 was prepared.

  Using the overcoat film photosensitive composition (3), an overcoat film was formed on the colored layer in the same manner as in Example 1 to obtain a color filter of Comparative Example 1.

<Comparative example 2>
[Preparation of photosensitive composition for overcoat film (4)]
100 parts by mass of (A) binder resin (1), 60 parts by mass of (B) ethylenically unsaturated compound: KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.), 8.4 parts by mass of (C) ) Photopolymerization initiator: Irgacure 907 (manufactured by Ciba Specialty Chemicals) was diluted with cyclohexanone so that the solid content in the resist was 30% by mass, and (A) relative to the mass of the binder resin solid content (B) The photosensitive composition (4) for protective films in which the mass ratio of the solid content of the ethylenically unsaturated compound was 0.6 was prepared.

  An overcoat film was formed on the colored layer in the same manner as in Example 1 except that the overcoat film photosensitive composition (4) was used, and a color filter of Comparative Example 2 was obtained.

<Comparative Example 3>
[Preparation of photosensitive composition for overcoat film (5)]
100 parts by mass of (A) binder resin (2), 100 parts by mass of (B) ethylenically unsaturated compound: KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.), 8.4 parts by mass of (C) ) Photopolymerization initiator: Irgacure 907 (manufactured by Ciba Specialty Chemicals) was diluted with cyclohexanone so that the solid content in the resist was 30% by mass, and (A) relative to the mass of the binder resin solid content (B) The photosensitive composition for protective films (5) in which the mass ratio of the solid content of the ethylenically unsaturated compound was 1.0 was prepared.

  The overcoat film was formed on the colored layer in the same manner as in Example 1 except that the overcoat film photosensitive composition (5) was used, and a color filter of Comparative Example 3 was obtained.

<Comparative example 4>
[Preparation of photosensitive composition for overcoat film (6)]
100 parts by mass of (A) binder resin (2), 80 parts by mass of (B) ethylenically unsaturated compound: KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.), 8.4 parts by mass of (C) ) Photopolymerization initiator: Irgacure 907 (manufactured by Ciba Specialty Chemicals) was diluted with cyclohexanone so that the solid content in the resist was 30% by mass, and (A) relative to the mass of the binder resin solid content (B) The photosensitive composition for protective films (6) in which the mass ratio of the solid content of the ethylenically unsaturated compound was 0.8 was prepared.

  Using the overcoat film photosensitive composition (6), an overcoat film was formed on the colored layer in the same manner as in Example 1, and a color filter of Comparative Example 4 was obtained.

<Comparative Example 5>
[Preparation of photosensitive composition for overcoat film (7)]
100 parts by mass of (A) binder resin (2), 40 parts by mass of (B) ethylenically unsaturated compound: KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.), 8.4 parts by mass of (C) ) Photopolymerization initiator: Irgacure 907 (manufactured by Ciba Specialty Chemicals) was diluted with cyclohexanone so that the solid content in the resist was 30% by mass, and (A) relative to the mass of the binder resin solid content (B) The photosensitive composition for protective film (7) in which the mass ratio of the solid content of the ethylenically unsaturated compound was 0.4 was prepared.

  Using the overcoat film photosensitive composition (7), an overcoat film was formed on the colored layer in the same manner as in Example 1 to obtain a color filter of Comparative Example 5.

[Evaluation]
The color filters of Examples 1 and 2 and Comparative Examples 1 to 4 were evaluated as follows, and the results are shown in Table 1.

（ビッカース硬度）
実施例１、２および、比較例１〜４で用いたオーバーコート膜用感光性組成物を、カラス基板上にスピンコートにて仕上り膜厚が１．５μｍとなるように塗布した後、９０℃で５分間乾燥し、全面に高圧水銀灯の光を３００ｍＪ／ｃｍ²照射し、アルカリ現像液にて６０秒間現像し、オーブンにて２３０℃で３０分焼成し、オーバーコート膜を形成した。このサンプルのビッカース硬度を、フィッシャー・インストルメンツ社製：微小膜硬度計ＨＭ２０００によって評価した。ビッカース硬度はビッカース圧子を用い、押し込み加重５ｍＮ、荷重速度０．２５ｍＮ／ｓｅｃ、荷重保持時間１秒で測定した。

(Vickers hardness)
The overcoat film photosensitive compositions used in Examples 1 and 2 and Comparative Examples 1 to 4 were applied on a crow substrate by spin coating so that the finished film thickness was 1.5 μm, and then 90 ° C. The whole surface was irradiated with 300 mJ / cm ² of light from a high-pressure mercury lamp, developed with an alkali developer for 60 seconds, and baked at 230 ° C. for 30 minutes in an oven to form an overcoat film. The Vickers hardness of this sample was evaluated with a HM2000 microfilm hardness meter manufactured by Fischer Instruments. The Vickers hardness was measured using a Vickers indenter with an indentation load of 5 mN, a load speed of 0.25 mN / sec, and a load holding time of 1 second.

(Adhesion)
First, as a substrate for adhesion evaluation, each of the pigment-dispersed resists of each color described in Example 1 was independently applied on a crow substrate by spin coating so that the finished film thickness was 1.8 μm, and then at 90 ° C. After drying for 5 minutes, the entire surface was irradiated with light of a high-pressure mercury lamp at 300 mJ / cm ² , developed with an alkali developer for 60 seconds, and baked at 230 ° C. for 30 minutes in an oven.
Thereafter, each of the overcoat film photosensitive compositions (1) to (7) used in Examples 1 and 2 and Comparative Examples 1 to 5 had a film thickness of 1 on the glass substrate on which the above-described colored layer was formed. Spin coated to 5 μm and dried at 90 ° C. for 5 minutes. Without using a photomask, the light from a high-pressure mercury lamp was irradiated at 150 mJ / cm ² . Then, it developed using the developing solution similar to preparation of a colored layer. After washing with water, baking was performed at 230 ° C. for 30 minutes, and an overcoat layer was formed on the colored layer to obtain an evaluation substrate.
Adhesion was evaluated by a cross cellophane tape peeling test (JIS-K5400). That is, a grid-like cut with a 1 mm interval is made with a cutter knife, cellophane tape is applied, the coating film after peeling is confirmed, and an object that does not peel off between the colored layer and the overcoat layer is marked on the periphery of the cut. A case where peeling occurred was evaluated as Δ, and a case where peeling occurred as a whole was evaluated as ×.

(ITO wrinkles)
A substrate was prepared in the same manner as the adhesion evaluation sample, and an ITO film was formed on the entire surface of the laminated substrate of the colored layer and the overcoat film so as to have a thickness of 150 nm by sputtering. After baking this board | substrate for 60 minutes at 250 degreeC, it observed with the microscope and evaluated what was (circle) and the thing without a wrinkle what was able to confirm a wrinkle.

(Flatness)
The steps of the color filter substrates produced in Examples 1 and 2 and Comparative Examples 1 to 4 were measured, x having a step of 0.5 μm or more, Δ being 0.3 μm or more and less than 0.5 μm, The thing less than 0.3 micrometer was evaluated as (circle).

(Light transmittance)
The transmittance of the sample produced by the same method as that for the sample for measuring the Vickers hardness was evaluated by Olympus: microspectrophotometer OSP-200. The transmittance in the visible region of 400 nm to 700 nm was evaluated as x for less than 90%, Δ for 90% or more and less than 95%, and ○ for 95% or more. The reference was a glass substrate.

  As is clear from the results shown in Table 1, the color filter of the invention comprises (A) a binder resin and (B) a compound having an ethylenically unsaturated bond in the photosensitive resin composition forming the overcoat film. By making the mass ratio in a certain range and setting the Vickers hardness of the overcoat film to 50 to 65, the adhesion between the colored layer and the overcoat film is good, the ITO resistance is excellent, and the light transmittance is high. Good flatness.

Schematic which shows an example of the color filter of this invention in a cross section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Transparent substrate (glass substrate) 20 ... Black matrix 30 ... Colored layer 40 ... Flattening layer (overcoat film)
50 ... Transparent electrode layer

Claims (4)

An overcoat film obtained by hardening a photosensitive composition for an overcoat film comprising at least (A) a binder resin, (B) a compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator on a transparent substrate. In the color filter disposed on the colored layer,
The overcoat film is a photosensitivity for an overcoat film in which the mass ratio of the solid content of the compound (B) having an ethylenically unsaturated bond to the mass of (A) the binder resin solid content is 0.6 or more and 1.0 or less. A color filter, which is a hard film of the composition and has a Vickers hardness of 50 to 65 in the overcoat film.   The color filter according to claim 1, wherein the overcoat film has a light transmittance of 90% or more in a visible region of 400 nm to 700 nm.   3. The color filter according to claim 1, wherein a step on the surface of the color filter after the overcoat film is disposed is less than 0.3 μm.   The color filter according to claim 1, wherein the overcoat film has a thickness of 1.0 μm or more and 5.0 μm or less.

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