JP7737779B2 - Photosensitive resin composition for black resist, and light-shielding film and color filter obtained by curing the same - Google Patents

Description

The present invention relates to a photosensitive resin composition for black resist, and a light-shielding film and color filter obtained by curing the composition.

In recent years, advances in mobile devices have led to an increase in display devices such as touch panels and LCD panels for use outdoors or in vehicles. In these display devices, the outer frame of the touch panel is provided with a light-shielding film to block light leakage from the periphery of the LCD panel on the back, and the LCD panel is provided with a black matrix to prevent light leakage from the screen when displaying black and to prevent color mixing between adjacent color resists.

In display devices and the like, in order to suppress light leakage and improve the visibility of the screen of the display device, the concentration of black pigment in the light-shielding film is sometimes increased to increase the light-shielding properties of the film (reducing the light transmittance of the film). Because the refractive index of black pigment is higher than that of the transparent substrate and curable resin, increasing the concentration of black pigment in the light-shielding film increases the reflectance when viewed from the side of the transparent substrate opposite the side on which the light-shielding film is formed. This increases reflection at the interface between the transparent substrate and the light-shielding film formed on it, causing problems such as reflections on the light-shielding film and the black matrix boundary becoming more noticeable due to differences in reflectance with the colored portion of the color filter.

Therefore, there is a demand for a photosensitive resin composition for black resist that has both high light-blocking properties and low reflectance, as well as light-blocking films and color filters obtained by curing the composition.

For example, Patent Document 1 discloses a black photosensitive resin composition that contains hydrophobic silica microparticles and a specific dispersant (urethane-based dispersant). It is said that the use of hydrophobic silica microparticles and a specific dispersant makes it possible to form a black matrix that combines high light-blocking properties with low reflectance.

JP 2015-161815 A

However, the inventors' investigations have revealed that the black photosensitive resin composition described in Patent Document 1 was unable to produce a light-shielding film that possesses both high light-shielding properties and low reflectance. Furthermore, in light-shielding films for sensors such as various display devices and solid-state imaging devices, depending on the design of the device configuration, there are cases where it is necessary to reduce the reflectance of the transparent substrate side of the light-shielding film coated on a transparent substrate such as glass, as well as cases where it is required to reduce the reflectance of the surface opposite to the surface in contact with the transparent substrate (hereinafter referred to as the "coated surface").

The present invention was made in consideration of these points, and aims to provide a photosensitive resin composition for black resist that has high light-blocking properties and low reflectance, as well as a light-blocking film and color filter obtained by curing the composition.

The photosensitive resin composition for black resist according to the present invention comprises (A) an unsaturated group-containing photosensitive resin, (B) a photopolymerizable monomer having at least two ethylenically unsaturated bonds, (C) a photopolymerization initiator, (D) at least one light-shielding component selected from a black pigment, a mixed color pigment, and a light-shielding material, and (E) silica particles, wherein the silica particles of component (E) are hollow particles.

The light-shielding film according to the present invention is composed of the above-mentioned photosensitive resin composition for black resist.

The color filter of the present invention has the above-mentioned light-shielding film as a black matrix.

The present invention provides a photosensitive resin composition for black resist that has high light-shielding properties and low reflectance, as well as a light-shielding film and a color filter that use the same. Furthermore, when formed on a transparent substrate, the light-shielding film of the present invention not only reduces reflectivity on the transparent substrate side, but also contributes to reducing reflectivity on the coated surface of the light-shielding film.

The present invention will be described in detail below. The photosensitive resin composition for black resist of the present invention (hereinafter referred to as the photosensitive resin composition) contains components (A) to (E). Components (A) to (E) will be described below.

(Component (A))
The unsaturated group-containing photosensitive resin (A) preferably has a polymerizable unsaturated group and an acidic group for exhibiting alkali solubility in one molecule, and more preferably has both a polymerizable unsaturated group and a carboxy group. The above resins can be widely used without any particular limitations.

An example of the unsaturated group-containing photosensitive resin is an epoxy (meth)acrylate acid adduct obtained by reacting an epoxy compound having two glycidyl ether groups derived from a bisphenol (hereinafter also referred to as a "bisphenol-type epoxy compound represented by general formula (1)") with (meth)acrylic acid, and then reacting the resulting compound having a hydroxy group with a polybasic carboxylic acid or its anhydride. An epoxy compound derived from a bisphenol refers to an epoxy compound obtained by reacting a bisphenol with an epihalohydrin, or an equivalent thereof. Note that "(meth)acrylic acid" is a general term for acrylic acid and methacrylic acid, and can refer to either or both of these.

The unsaturated group-containing photosensitive resin, component (A), is preferably a bisphenol-type epoxy compound represented by general formula (1).

(In formula (1), R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogen atom; X represents —CO—, —SO ₂ —, —C(CF ₃ ) ₂ —, —Si(CH ₃ ) 2 —, —CH ₂ —, —C(CH _{3 ) 2} —, —O—, a fluorene-9,9-diyl group represented by formula (2) or a single bond; and 1 represents an integer of 0 to 10.)

The bisphenol-type epoxy compound represented by general formula (1) is an epoxy compound having two glycidyl ether groups obtained by reacting a bisphenol with epichlorohydrin. This reaction generally involves oligomerization of the diglycidyl ether compound, and therefore contains an epoxy compound containing two or more bisphenol skeletons.

Examples of bisphenols that can be used in this reaction include bis(4-hydroxyphenyl)ketone, bis(4-hydroxy-3,5-dimethylphenyl)ketone, bis(4-hydroxy-3,5-dichlorophenyl)ketone, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxy-3,5-dimethylphenyl)sulfone, bis(4-hydroxy-3,5-dichlorophenyl)sulfone, bis(4-hydroxyphenyl)hexafluoropropane, bis(4-hydroxy-3,5-dimethylphenyl)hexafluoropropane, bis(4-hydroxyphenyl) bis(4-hydroxyphenyl)hexafluoropropane, bis(4-hydroxyphenyl)dimethylsilane, bis(4-hydroxy-3,5-dimethylphenyl)dimethylsilane, bis(4-hydroxy-3,5-dichlorophenyl)dimethylsilane, bis(4-hydroxyphenyl)methane, bis(4-hydroxy-3,5-dichlorophenyl)methane, bis(4-hydroxy-3,5-dibromophenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3-chlorophenyl)propane, bis(4-hydroxyphenyl)ether, bis(4-hydroxy-3,5-dimethylphenyl)ether, bis(4-hydroxy-3,5-dichlorophenyl)ether, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 9,9-bis(4-hydroxy 9,9-bis(4-hydroxy-3-chlorophenyl)fluorene, 9,9-bis(4-hydroxy-3-bromophenyl)fluorene, 9,9-bis(4-hydroxy-3-fluorophenyl)fluorene, 9,9-bis(4-hydroxy-3-methoxyphenyl)fluorene, 9,9-bis(4-hydroxy-3,5-dimethylphenyl)fluorene, 9,9-bis(4-hydroxy-3,5-dichlorophenyl)fluorene, 9,9-bis(4-hydroxy-3,5-dibromophenyl)fluorene, 4,4'-biphenol, 3,3'-biphenol, etc. Among these, bisphenols having a fluorene-9,9-diyl group are preferred.

Furthermore, examples of (a) dicarboxylic acid or tricarboxylic acid monoanhydrides that can be reacted with the hydroxy groups in the epoxy (meth)acrylate molecule obtained by reacting such an epoxy compound with (meth)acrylic acid include acid monoanhydrides of open-chain hydrocarbon dicarboxylic or tricarboxylic acids, acid monoanhydrides of alicyclic dicarboxylic or tricarboxylic acids, and acid monoanhydrides of aromatic dicarboxylic or tricarboxylic acids. Examples of open-chain hydrocarbon dicarboxylic or tricarboxylic acid monoanhydrides include succinic acid, acetylsuccinic acid, maleic acid, adipic acid, itaconic acid, azelaic acid, citramalic acid, malonic acid, glutaric acid, citric acid, tartaric acid, oxoglutaric acid, pimelic acid, sebacic acid, suberic acid, and diglycolic acid. Furthermore, acid monoanhydrides of dicarboxylic or tricarboxylic acids into which optional substituents have been introduced are also included. Examples of alicyclic dicarboxylic or tricarboxylic acid monoanhydrides include cyclobutanedicarboxylic acid, cyclopentanedicarboxylic acid, hexahydrophthalic acid, tetrahydrophthalic acid, norbornanedicarboxylic acid, and the like. They also include dicarboxylic or tricarboxylic acid monoanhydrides into which any substituent has been introduced. Examples of aromatic dicarboxylic or tricarboxylic acid monoanhydrides include phthalic acid, isophthalic acid, trimellitic acid, and the like. They also include dicarboxylic or tricarboxylic acid monoanhydrides into which any substituent has been introduced.

Furthermore, examples of (a) dicarboxylic acid or tricarboxylic acid monoanhydrides that can be reacted with the hydroxy groups in the epoxy (meth)acrylate molecule obtained by reacting such an epoxy compound with (meth)acrylic acid include monoanhydrides of open-chain hydrocarbon dicarboxylic acids or tricarboxylic acids, monoanhydrides of alicyclic dicarboxylic acids or tricarboxylic acids, and monoanhydrides of aromatic dicarboxylic acids or tricarboxylic acids. Examples of open-chain hydrocarbon dicarboxylic acid or tricarboxylic acid monoanhydrides include succinic acid, acetylsuccinic acid, maleic acid, adipic acid, itaconic acid, azelaic acid, citramalic acid, malonic acid, glutaric acid, citric acid, tartaric acid, oxoglutaric acid, pimelic acid, sebacic acid, suberic acid, and diglycolic acid. Furthermore, examples of dicarboxylic acid or tricarboxylic acid monoanhydrides with optional substituents introduced therein are also included. Examples of alicyclic dicarboxylic or tricarboxylic acid monoanhydrides include cyclobutanedicarboxylic acid, cyclopentanedicarboxylic acid, hexahydrophthalic acid, tetrahydrophthalic acid, norbornanedicarboxylic acid, and the like. They also include dicarboxylic or tricarboxylic acid monoanhydrides into which any substituent has been introduced. Examples of aromatic dicarboxylic or tricarboxylic acid monoanhydrides include phthalic acid, isophthalic acid, trimellitic acid, and the like. They also include dicarboxylic or tricarboxylic acid monoanhydrides into which any substituent has been introduced.

The molar ratio (a)/(b) of (a) dicarboxylic or tricarboxylic acid anhydride to (b) tetracarboxylic acid dianhydride to be reacted with the epoxy (meth)acrylate is preferably 0.01 to 10.0, and more preferably 0.02 or more and less than 3.0. It is undesirable for the molar ratio (a)/(b) to deviate from the above range, as this will prevent the optimum molecular weight from being obtained to create a photosensitive resin composition with good photopatterning properties. Note that the smaller the molar ratio (a)/(b), the larger the molecular weight and the lower the alkali solubility tends to be.

The reaction between the epoxy compound and (meth)acrylic acid, and the reaction between the epoxy (meth)acrylate obtained by this reaction and a polybasic acid or its acid anhydride, are not particularly limited, and known methods can be used. The unsaturated group-containing photosensitive resin synthesized by the above reaction preferably has a weight average molecular weight (Mw) of 2,000 to 10,000 and an acid value of 30 to 200 mg/KOH.

Another example of a resin suitable for the unsaturated group-containing photosensitive resin (component (A)) is a copolymer of (meth)acrylic acid, (meth)acrylic acid esters, etc., and includes a resin having a (meth)acryloyl group and a carboxy group. Examples of such resins include alkali-soluble resins containing polymerizable unsaturated groups, which can be obtained by copolymerizing (meth)acrylic acid esters, including glycidyl (meth)acrylate, in a solvent to obtain a copolymer, reacting the copolymer with (meth)acrylic acid, and finally reacting the copolymer with an anhydride of a dicarboxylic acid or tricarboxylic acid. Examples of the copolymer include a copolymer disclosed in Japanese Patent Application Laid-Open No. 2014-111722, which is composed of 20 to 90 mol% repeating units derived from diester glycerol in which both hydroxyl groups have been esterified with (meth)acrylic acid and 10 to 80 mol% repeating units derived from one or more polymerizable unsaturated compounds copolymerizable therewith, and which has a number average molecular weight (Mn) of 2,000 to 20,000 and an acid value of 35 to 120 mgKOH/g; and a polymerizable unsaturated group-containing alkali-soluble resin disclosed in Japanese Patent Application Laid-Open No. 2018-141968, which is a polymer having a weight average molecular weight (Mw) of 3,000 to 50,000 and an acid value of 30 to 200 mg/KOH, and which includes units derived from (meth)acrylic acid ester compounds and units having a (meth)acryloyl group and a di- or tricarboxylic acid residue.

The unsaturated group-containing photosensitive resin of component (A) may be used alone or in combination with two or more types.

((B) component)
Examples of the photopolymerizable monomer having at least two ethylenically unsaturated bonds in component (B) include 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, glycerol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and pentaerythritol. Examples of the photopolymerizable monomer include (meth)acrylic acid esters such as tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, glycerol tri(meth)acrylate, sorbitol penta(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, sorbitol hexa(meth)acrylate, alkylene oxide-modified hexa(meth)acrylate of phosphazene, and caprolactone-modified dipentaerythritol hexa(meth)acrylate, and compounds having an ethylenic double bond include dendritic polymers having a (meth)acrylic group. One of these monomers may be used alone, or two or more may be used in combination. Furthermore, the photopolymerizable monomer having at least two ethylenically unsaturated bonds can serve to crosslink molecules of the alkali-soluble resin contained therein. To achieve this function, it is preferable to use a monomer having three or more photopolymerizable groups. The acrylic equivalent, calculated by dividing the molecular weight of the monomer by the number of (meth)acrylic groups in one molecule, is preferably 50 to 300, and more preferably 80 to 200. Component (B) does not have any free carboxy groups.

Examples of dendritic polymers having (meth)acryloyl groups as compounds having ethylenic double bonds that can be included in the composition as component (B) include dendritic polymers obtained by adding a polyvalent mercapto compound to some of the carbon-carbon double bonds in the (meth)acryloyl groups of a polyfunctional (meth)acrylate. Specific examples include dendritic polymers obtained by reacting the (meth)acryloyl groups of a polyfunctional (meth)acrylate represented by general formula (3) with a polyvalent mercapto compound represented by general formula (4).

(In formula (3), R ₅ is a hydrogen atom or a methyl group, and R ₆ is the remaining portion obtained by donating n hydroxy groups out of k hydroxy groups of R ₇ (OH) _k to the ester bond in the formula. Preferred R ₇ (OH) _k is a polyhydric alcohol based on a non-aromatic straight-chain or branched-chain hydrocarbon skeleton having 2 to 8 carbon atoms, a polyhydric alcohol ether formed by linking multiple molecules of the polyhydric alcohol via ether bonds by dehydration condensation of the alcohol, or an ester of such a polyhydric alcohol or polyhydric alcohol ether with a hydroxy acid. k and n independently represent integers of 2 to 20, provided that k≧n.)

(In formula (4), _R8 is a single bond or a divalent to hexavalent C1 to C6 hydrocarbon group, and m is 2 when _R8 is a single bond, and is an integer from 2 to 6 when _R8 is a divalent to hexavalent group.)

Examples of polyfunctional (meth)acrylates represented by general formula (3) include (meth)acrylic acid esters such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and caprolactone-modified pentaerythritol tri(meth)acrylate. These compounds may be used alone or in combination of two or more.

Examples of polyvalent mercapto compounds represented by general formula (4) include trimethylolpropane tri(mercaptoacetate), trimethylolpropane tri(mercaptopropionate), pentaerythritol tetra(mercaptoacetate), pentaerythritol tri(mercaptoacetate), pentaerythritol tetra(mercaptopropionate), dipentaerythritol hexa(mercaptoacetate), dipentaerythritol hexa(mercaptopropionate), etc. These compounds may be used alone or in combination of two or more.

The blending ratio of component (A) to component (B), expressed as a weight ratio (A)/(B), is preferably 30/70 to 90/10, and more preferably 60/40 to 80/20. When the blending ratio of component (A) is 30/70 or more, the cured product after photocuring is less likely to become brittle, and the acid value of the coating film is less likely to decrease in the unexposed areas, thereby preventing a decrease in solubility in alkaline developer. This reduces the likelihood of problems such as jagged or unsharp pattern edges. Furthermore, when the blending ratio of component (A) is 90/10 or less, the proportion of photoreactive functional groups in the resin is sufficient, allowing the desired crosslinked structure to be formed. Furthermore, because the acid value of the resin component is not too high, the solubility in alkaline developer in the exposed areas is less likely to increase, preventing the formed pattern from being thinner than the target line width or pattern loss.

((C) component)
Examples of the photopolymerization initiator (C) include acetophenones such as acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, dichloroacetophenone, trichloroacetophenone, and p-tert-butylacetophenone; benzophenones such as benzophenone, 2-chlorobenzophenone, and p,p'-bisdimethylaminobenzophenone; benzoin ethers such as benzil, benzoin, benzoin methyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; 2-(o-chlorophenyl)-4,5-phenylbiimidazole, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)biimidazole, 2-(o-fluorophenyl)-4,5-diphenylbiimidazole, 2-(o-methoxyphenyl)-4,5-diphenylbiimidazole, 2,4, Biimidazole compounds such as 5-triarylbiimidazole; halomethylthiazole compounds such as 2-trichloromethyl-5-styryl-1,3,4-oxadiazole, 2-trichloromethyl-5-(p-cyanostyryl)-1,3,4-oxadiazole, and 2-trichloromethyl-5-(p-methoxystyryl)-1,3,4-oxadiazole; 2,4,6-tris(trichloromethyl)-1,3,5-triazinyl 2-methyl-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-phenyl-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(4-chlorophenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)- halomethyl-S-triazine compounds such as 1,3,5-triazine, 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(3,4,5-trimethoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine, and 2-(4-methylthiostyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine; 1-(4-phenylthio)phenyl]-, 2-(O-benzoyloxime), 1-(4-phenylsulfanylphenyl)butane-1,2-dione-2-oxime-O-benzoate, 1-(4-methylsulfanylphenyl)butane-1,2-dione-2-oxime-O-acetate, 1-(4-methylsulfanylphenyl)butan-1-one oxime-O-acetate, 4-ethoxy-2-methylphenyl-9-ethyl-6-nitro O-acyloxime compounds such as 9H-carbazol-3-yl-O-acetyloxime; sulfur compounds such as benzyl dimethyl ketal, thioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2-methylthioxanthone, and 2-isopropylthioxanthone; anthraquinones such as 2-ethylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, and 2,3-diphenylanthraquinone; organic peroxides such as azobisisobutyronitrile, benzoyl peroxide, and cumene peroxide; thiol compounds such as 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, and 2-mercaptobenzothiazole; and tertiary amines such as triethanolamine and triethylamine. These photopolymerization initiators may be used alone or in combination of two or more.

In particular, when preparing a photosensitive resin composition containing a colorant, it is preferable to use O-acyloxime compounds (including ketoximes). Examples of compounds that can be preferably used include O-acyloxime photopolymerization initiators represented by general formulas (5) and (6). Among these compounds, when using a colorant at a high pigment concentration or when forming a light-shielding film pattern, it is preferable to use an O-acyloxime photopolymerization initiator with a molar absorption coefficient at 365 nm of 10,000 or more. In this specification, the term "photopolymerization initiator" is used to include sensitizers.

(In formula (5), R ₉ and R ₁₀ each independently represent a C1 to C15 alkyl group, a C6 to C18 aryl group, a C7 to C20 arylalkyl group, or a C4 to C12 heterocyclic group; and R ₁₁ represents a C1 to C15 alkyl group, a C6 to C18 aryl group, or a C7 to C20 arylalkyl group. Here, the alkyl group and aryl group may be substituted with a C1 to C10 alkyl group, a C1 to C10 alkoxy group, a C1 to C10 alkanoyl group, or a halogen; and the alkylene portion may contain an unsaturated bond, an ether bond, a thioether bond, or an ester bond. The alkyl group may be a linear, branched, or cyclic alkyl group.)

(In formula (6), R ₁₂ and R ₁₃ each independently represent a linear or branched alkyl group having 1 to 10 carbon atoms, a cycloalkyl group, cycloalkylalkyl group, or alkylcycloalkyl group having 4 to 10 carbon atoms, or a phenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms. R ₁₄ each independently represent a linear or branched alkyl group or alkenyl group having 2 to 10 carbon atoms, and some of the —CH ₂ — groups in the alkyl group or alkenyl group may be substituted with —O— groups. Furthermore, some of the hydrogen atoms in these groups R ₁₂ to R ₁₄ may be substituted with halogen atoms.)

The amount of photopolymerization initiator (C) used is preferably 3 to 30 parts by weight, and more preferably 5 to 20 parts by weight, based on 100 parts by weight of the total of components (A) and (B). When the blending ratio of component (C) is 3 parts by weight or more, good sensitivity is achieved and a sufficient photopolymerization speed can be achieved. When the blending ratio of component (C) is 30 parts by weight or less, appropriate sensitivity can be achieved, making it possible to obtain the desired pattern line width and desired pattern edge.

((D) component)
The light-shielding components such as black pigments, mixed-color organic pigments, and light-shielding materials of component (D) that can be used in the present invention are not particularly limited, and any known light-shielding components can be used as long as they are dispersed with an average particle size of 1 to 1,000 nm (average particle size measured with a laser diffraction/scattering particle size distribution meter or a dynamic light scattering particle size distribution meter).

Examples of black pigments for component (D) include perylene black, cyanine black, aniline black, lactam black, carbon black, and titanium black.

Examples of the mixed-color organic pigment of component (D) include a pigment in which at least two colors are mixed, selected from organic pigments such as azo pigments, condensed azo pigments, azomethine pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, isoindoline pigments, dioxazine pigments, threne pigments, perylene pigments, perinone pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, and thioindigo pigments.

The above component (D) may be used alone or in combination with two or more types, depending on the desired function of the photosensitive resin composition.

Examples of organic pigments that can be used when a mixed color organic pigment is used as component (D) include, but are not limited to, those having the following color index numbers:
Pigment Red 2, 3, 4, 5, 9, 12, 14, 22, 23, 31, 38, 112, 122, 144, 146, 147, 149, 166, 168, 170, 175, 176, 177, 178, 179, 184, 185, 187, 188, 202, 207, 208, 209, 210, 213, 214, 220, 221, 242, 247, 253, 254, 255, 256, 257, 262, 264, 266, 272, 279, etc. Pigment Orange 5, 13, 16, 34, 36, 38, 43, 61, 62, 64, 67, 68, 71, 72, 73, 74, 81, etc. Pigment Yellow 1, 3, 12, 13, 14, 16, 17, 55, 73, 74, 81, 83, 93, 95, 97, 109, 110, 111, 117, 120, 126, 127, 128, 129, 130, 136, 138, 139, 150, 151, 153, 154, 155, 173, 174, 175, 176, 180, 181, 183, 185, 191, 194, 199, 213, 214, etc. Pigment Green 7, 36, 58, etc. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 60, 80, etc. Pigment Violet 19, 23, 37, etc.

The blending ratio of the light-blocking component (D) can be determined arbitrarily depending on the desired light-blocking degree, but is preferably 20 to 80 mass %, and more preferably 40 to 70 mass %, based on the solid components in the photosensitive resin composition. When an organic pigment such as aniline black, cyanine black, or lactam black, or a carbon-based light-blocking component such as carbon black, is used as the light-blocking component (D), a blending ratio of 40 to 60 mass % based on the solid components in the photosensitive resin composition is particularly preferred. When the light-blocking component is 20 mass % or more based on the solid components in the photosensitive resin composition, sufficient light-blocking properties can be obtained. When the light-blocking component is 80 mass % or less based on the solid components in the photosensitive resin composition, the content of the photosensitive resin, which originally serves as a binder, is not reduced, allowing the desired development characteristics and film-forming ability to be obtained.

The above-mentioned component (D) is usually dispersed in a solvent to form a light-blocking component dispersion, which is then mixed with other formulation components. In this case, a dispersant can be added. The dispersant can be any known compound used to disperse pigments (light-blocking components) (compounds commercially available under the names of dispersants, dispersing wetting agents, dispersion promoters, etc.), and can be used without any particular restrictions.

Examples of dispersants include cationic polymer dispersants, anionic polymer dispersants, nonionic polymer dispersants, and pigment derivative dispersants (dispersing aids). In particular, cationic polymer dispersants are preferred, which have cationic functional groups such as imidazolyl, pyrrolyl, pyridyl, or primary, secondary, or tertiary amino groups as adsorption sites for the colorant, and have an amine value of 1 to 100 mg KOH/g and a number-average molecular weight (Mn) of 1,000 to 100,000. The blending amount of this dispersant is preferably 1 to 35% by weight, and more preferably 2 to 25% by weight, of the light-blocking component. High-viscosity substances such as resins generally have the effect of stabilizing dispersion, but those without dispersion-promoting properties are not considered dispersants. However, this does not limit their use for the purpose of stabilizing dispersion.

((E) component)
The silica particles as component (E) may be produced by a gas phase reaction or a liquid phase reaction, and there are no particular limitations on their shape (spherical or non-spherical).

The silica particles used as component (E) in the present invention are preferably hollow silica particles. Note that "hollow silica particles" refer to silica particles that have a cavity inside the particle.

Silica particles containing a gas therein, such as the silica particles described above, have high dispersibility, and therefore provide good pattern linearity for the cured film (light-shielding film) obtained by curing the photosensitive resin composition of the present invention. Furthermore, by using silica particles containing a gas therein, the refractive index of the light-shielding film containing the silica particles can be reduced.

The average particle size of the silica particles is preferably 40 to 100 nm, and more preferably 50 to 80 nm. When the average particle size is within this range, the mechanical strength of the silica particles themselves is high, making them less likely to break even if they are hollow. Furthermore, compared to small particle sizes of a few nm, silica particles within this size range are less likely to aggregate. As a result, within this particle size range, silica particles have excellent dispersion stability and can be uniformly present within the light-shielding film. Therefore, variations in reflectance on the light-shielding film are less likely to occur.

Furthermore, when the content is within the above range, the proportion of hollow spaces within the silica particles (hereinafter referred to as porosity) can also be adjusted. Because the refractive index of the silica particles varies depending on the particle size, it becomes easier to adjust the refractive index of the light-blocking film regardless of the material of the transparent substrate. Note that "porosity" refers to the proportion of hollow spaces within the particle.

The average particle size of the silica particles can be determined by randomly selecting 100 particles, measuring the long and short axis lengths of the particles, and taking the arithmetic average of these. The average particle size of the silica particles can also be measured by the cumulant method using a dynamic light scattering particle size distribution analyzer, the Particle Size Analyzer FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.).

The refractive index of the silica particles is preferably 1.10 to 1.41, and more preferably 1.10 to 1.35. By using the silica particles, which have a lower refractive index than ordinary silica particles (1.45 to 1.47), the refractive index of the light-shielding film can be made lower than the refractive index of a light-shielding film containing only ordinary silica particles.

The refractive index of silica particles can also be determined from a transparent mixture obtained by mixing the above-mentioned silica particles processed into a powder with a standard refractive index liquid of known refractive index. In this case, the refractive index of the standard refractive index liquid in the above-mentioned mixture is taken as the refractive index of the silica particles. The refractive index of the above-mentioned silica particles can be measured using an Abbe refractometer.

The higher the porosity of the silica particles, the lower the refractive index. Therefore, the porosity of the silica particles is preferably 20% by volume or more, more preferably 20 to 95% by volume, more preferably 25 to 90% by volume, even more preferably 30 to 90% by volume, and particularly preferably 35 to 90% by volume. When the porosity is within the above range, a light-shielding film with the desired refractive index can be easily obtained. Furthermore, since reflection caused by the difference in refractive index between the transparent substrate and the light-shielding film formed can be suppressed, reflection can be suppressed without the need to provide a separate anti-reflection film or the like on the substrate.

Furthermore, by setting the porosity of the silica particles within the above range, the weight of the silica particles can be made lighter than that of ordinary silica particles. Therefore, unlike ordinary silica particles, the silica particles are thought to be less likely to settle toward the transparent substrate, even when in a photosensitive resin composition or when coated on a transparent substrate. This results in the silica particles being uniformly dispersed in the light-shielding film, which reduces not only the reflectance when viewed from the transparent substrate side, but also the reflectance when viewed from the cured film side (the light-shielding film surface side).

The porosity of the silica particles can be determined using a transmission electron microscope. The hollow portions of silica particles have a low density, and the contrast of the hollow portions is low in transmission electron microscope photographs, making it possible to identify the shell and hollow portions of the silica particles. From the microscope photograph, the longest and shortest diameters of the silica particles are first measured, and the volume (V ₁ ) is calculated assuming the particle shape is spherical, with the average value being the particle diameter of the particle. Next, the longest and shortest diameters of the hollow portions of the particle are measured, and the average value is used as the cavity diameter, with the volume (V ₂ ) calculated assuming the hollow portion shape is spherical. The porosity can be expressed as the ratio of the volume (V _{2 ) to the volume (V 1 )} .

As mentioned above, the shape of the silica particles is not particularly limited as long as they have the desired porosity. They may be spherical or elliptical. It is preferable that the silica particles used in the present invention have a spherical shape.

The above silica particles preferably have a sphericity of 1.05 to 1.5. If the sphericity of the silica particles is within this range, the particle shape will be close to a perfect sphere. This allows them to be filled homogeneously into a thin light-shielding film, allowing the formation of a light-shielding film in which the silica particles are not exposed to the outside from the film surface while maintaining the film surface smoothness. This makes it possible to obtain a light-shielding film with a low refractive index and sufficient strength.

The sphericity of the silica particles can be determined from the ratio of the longest diameter to the shortest diameter of the particles (the average value of 100 arbitrary silica particles). Here, the longest diameter and shortest diameter of the silica particles are values determined by photographing the silica particles with a transmission electron microscope and measuring the longest diameter and shortest diameter of the silica particles from the resulting microscopic photograph.

The dispersion used in the photosensitive resin composition of the present invention can be prepared by mixing and dispersing the above components (A) to (E) using an appropriate method.

(solvent)
In addition to the components (A) to (E), the photosensitive resin composition of the present invention preferably uses a solvent as component (F). Examples of the solvent include alcohols such as methanol, ethanol, n-propanol, isopropanol, ethylene glycol, and propylene glycol; terpenes such as α- or β-terpineol; ketones such as acetone, methyl ethyl ketone, cyclohexanone, and N-methyl-2-pyrrolidone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; cellosolve, methyl cellosolve, ethyl cellosolve, carbitol, methyl carbitol, ethyl carbitol, butyl carbitol, propylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples of suitable acetic acid esters include glycol ethers such as dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monomethyl ether, and triethylene glycol monoethyl ether; and acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate. These can be dissolved and mixed alone or in combination of two or more to form a uniform solution composition.

The photosensitive resin composition of the present invention can also contain additives such as resins other than component (A), such as epoxy resins, curing agents, curing accelerators, thermal polymerization inhibitors and antioxidants, plasticizers, fillers other than hollow silica, leveling agents, antifoaming agents, surfactants, and coupling agents, as needed.

Examples of thermal polymerization inhibitors and antioxidants include hydroquinone, hydroquinone monomethyl ether, pyrogallol, tert-butylcatechol, phenothiazine, and hindered phenol compounds. Examples of plasticizers include dibutyl phthalate, dioctyl phthalate, and tricresyl phosphate. Examples of fillers include glass fiber, silica, mica, and alumina. Examples of antifoaming agents and leveling agents include silicone-based, fluorine-based, and acrylic compounds. Examples of surfactants include fluorine-based surfactants and silicone-based surfactants. Examples of coupling agents include 3-(glycidyloxy)propyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, and 3-ureidopropyltriethoxysilane.

The photosensitive resin composition of the present invention preferably contains a total of 80% by mass or more, and more preferably 90% by mass or more, of the unsaturated group-containing photosensitive resin (component (A)), the photopolymerizable monomer having at least two ethylenically unsaturated bonds (component (B)), the photopolymerization initiator (component (C)), the light-shielding component (component (D)), and the hollow silica particles (component (E)) in the solids (including the monomers that become solids after curing) excluding the solvent (component (F)). The amount of solvent varies depending on the target viscosity, but is preferably 40 to 90% by mass of the total amount.

In addition, a light-shielding film obtained by curing the photosensitive resin composition of the present invention can be obtained, for example, by applying a solution of the photosensitive resin composition to a substrate or the like, drying the solvent, and curing the composition by irradiating it with light (including ultraviolet light, radiation, etc.). By using a photomask or the like to define areas that are exposed to light and areas that are not, only the areas that are exposed to light can be cured, and the other areas can be dissolved in an alkaline solution, resulting in the desired pattern.

A color filter having the light-shielding film of the present invention as a black matrix can be produced, for example, by forming a light-shielding film having a thickness of 1.0 to 2.0 μm on a transparent substrate, and then forming red, blue, and green pixels by photolithography after forming the light-shielding film, or by injecting red, blue, and green inks into the light-shielding film by an inkjet process.

The light-shielding film obtained by curing the photosensitive resin composition of the present invention can also be used as a black column spacer in a liquid crystal display device. For example, a single black resist can be used to create multiple sections with different film thicknesses, with one section functioning as a spacer and the other section functioning as a black matrix.

Specific examples of each step in the method for forming a light-shielding film by applying and drying a photosensitive resin composition are provided below.

The photosensitive resin composition can be applied to a substrate by any of the known methods, including immersion in a solution, spraying, or using a roller coater, land coater, slit coater, or spinner. After applying the composition to the desired thickness using these methods, a coating is formed by removing the solvent (prebaking). Prebaking can be performed by heating in an oven or hot plate, vacuum drying, or a combination of these. The heating temperature and time for prebaking can be selected appropriately depending on the solvent used, but it is preferable to perform the prebaking at 80 to 120°C for 1 to 10 minutes, for example.

Radiation used for exposure can be, for example, visible light, ultraviolet light, far ultraviolet light, electron beams, or X-rays, with the wavelength of the radiation preferably ranging from 250 to 450 nm. Developers suitable for this alkaline development include aqueous solutions of sodium carbonate, potassium carbonate, potassium hydroxide, diethanolamine, tetramethylammonium hydroxide, and the like. These developers can be selected appropriately based on the characteristics of the resin layer, and adding a surfactant is also effective if necessary. The development temperature is preferably 20 to 35°C, and fine images can be precisely formed using commercially available developers or ultrasonic cleaners. After alkaline development, the substrate is typically washed with water. Development methods that can be used include shower development, spray development, dip (immersion) development, and puddle (puddle) development.

After development in this manner, a heat treatment (post-baking) is performed at 180-250°C for 20-100 minutes. This post-baking is performed for purposes such as increasing the adhesion between the patterned cured film (light-shielding film) and the substrate. Like pre-baking, this is performed by heating using an oven, hot plate, etc. The patterned cured film (light-shielding film) of the present invention is formed through various steps using photolithography. Then, polymerization or curing (sometimes collectively referred to as curing) is completed by heat, resulting in a light-shielding film with the desired pattern. The curing temperature in this case is preferably 160-250°C.

As mentioned above, the photosensitive resin composition for black resist of the present invention is not only suitable for forming fine patterns by exposure, alkaline development, and other procedures, but also can be used to form patterns by conventional screen printing, resulting in a light-shielding film with similar excellent light-shielding properties, adhesion, electrical insulation, heat resistance, and chemical resistance.

The photosensitive resin composition for black resist of the present invention can be suitably used as a coating material. In particular, color filter inks used in liquid crystal display devices or imaging devices, and the light-shielding films formed therefrom, are useful as color filters, black matrices for liquid crystal projection, and the like. Furthermore, the photosensitive resin composition for black resist of the present invention can be used not only as a color filter ink for color liquid crystal displays, but also as an ink material for color separation or light-shielding in various multicolor display devices, such as organic electroluminescent devices typified by organic EL devices, color liquid crystal display devices, color facsimiles, and image sensors. The color filter of the present invention can reduce reflection of external light at the interface between the colored layer (including the black resist layer) and the substrate, and, for example, reflection of light emitted from an organic EL device when used in an organic EL device. In other words, it is possible to improve contrast in bright areas by reducing reflection of external light, and to improve luminous efficiency by improving light extraction efficiency from the light-emitting side.

The following describes in detail the embodiments of the present invention based on examples and comparative examples, but the present invention is not limited to these.

First, we will explain the synthesis examples of the polymerizable unsaturated group-containing alkali-soluble resin (component (A)). Unless otherwise specified, the resins in these synthesis examples were evaluated as follows:

[Solid content concentration]
1 g of the resin solution obtained in the synthesis example was impregnated into a glass filter (weight: W ₀ (g)), weighed (W ₁ (g)), and the weight after heating at 160°C for 2 hours (W ₂ (g)) was calculated using the following formula.
Solid content concentration (wt%) = 100 x (W ₂ - W ₀ )/(W ₁ - W ₀ )

[Acid value]
The resin solution was dissolved in dioxane and titrated with a 1/10N KOH aqueous solution using a potentiometric titrator "COM-1600" (manufactured by Hiranuma Sangyo Co., Ltd.) to determine the content.

[Molecular weight]
Measurement was performed using gel permeation chromatography (GPC) "HLC-8220GPC" (manufactured by Tosoh Corporation, solvent: tetrahydrofuran, columns: TSKgelSuper H-2000 (2 columns) + TSKgelSuper H-3000 (1 column) + TSKgelSuper H-4000 (1 column) + TSKgelSuper H-5000 (1 column) (manufactured by Tosoh Corporation), temperature: 40°C, rate: 0.6 ml/min), and the weight average molecular weight (Mw) was determined as a value converted into standard polystyrene (manufactured by Tosoh Corporation, PS-oligomer kit).

[Average particle diameter]
The average particle size of the silica particles was determined by the cumulant method using a particle size distribution analyzer "Particle Size Analyzer FPAR-1000" (manufactured by Otsuka Electronics Co., Ltd.) that uses dynamic light scattering.

[Refractive index]
The refractive index of the silica particles was determined using an Abbe refractometer.

[Porosity]
The porosity of the silica particles was determined using a transmission electron microscope.

The abbreviations used in the synthesis examples and comparative synthesis examples are as follows.
BPFE: 9,9-bis(4-hydroxyphenyl)fluorene and chloromethyl
In the compound of general formula (1), X is a fluorocarbon.
9,9-ren-diyl, a compound in which R ₁ and R ₂ are hydrogen.
AA: Acrylic acid BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride THPA: Tetrahydrophthalic anhydride TEAB: Tetraethylammonium bromide PGMEA: Propylene glycol monomethyl ether acetate

[Synthesis Example]
BPFE (114.4 g, 0.23 mol), AA (33.2 g, 0.46 mol), PGMEA (157 g) and TEAB (0.48 g) were charged into a 500 ml four-neck flask equipped with a reflux condenser, and the mixture was stirred at 100 to 105 ° C for 20 hours to react. Next, BPDA (35.3 g, 0.12 mol) and THPA (18.3 g, 0.12 mol) were charged into the flask and stirred at 120 to 125 ° C for 6 hours to obtain a polymerizable unsaturated group-containing alkali-soluble resin (A). The solids concentration of the resulting resin solution was 56.1 mass%, the acid value (solids equivalent) was 103 mg KOH / g, and the Mw by GPC analysis was 3600.

The photosensitive resin compositions of Examples 1 to 5 and Comparative Examples 1 and 2 were prepared using the blending amounts (values are in mass %) shown in Table 1. The blending components used in the table are as follows:

(Polymerizable unsaturated group-containing alkali-soluble resin)
(A): Alkali-soluble resin solution obtained in the above Synthesis Example (solid content concentration: 56.1% by mass)

(Photopolymerizable monomer)
(B): A mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (Aronix M-405, manufactured by Toagosei Co., Ltd.)
"Aronix" is a registered trademark of the company.)

(Photopolymerization initiator)
(C)-1: Ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carboxylate]
Irgazol-3-yl]-, 1-(0-acetyloxime) (Irgac
URE OXE-02, manufactured by BASF Japan, "Irgacure"
is a registered trademark of the company)
(C)-2: ADEKA ARCLES NCI-831, manufactured by ADEKA Corporation, "ADEKA
"Cruise" is a registered trademark of the company.

(Carbon black dispersion)
(D): PGMEA dispersion (solid content 34.8% by mass) containing 25.0% by mass of carbon black and 10.0% by mass of polymer dispersant

(Silica dispersion)
(E)-1: Hollow silica isopropanol dispersion sol
(JGC Catalysts and Chemicals Co., Ltd., solid content 20% by weight, average particle size approximately 50 nm,
Porosity 30% by volume, refractive index 1.30)
(E)-2: Hollow silica isopropanol dispersion sol
(JGC Catalysts and Chemicals Co., Ltd., solid content 20% by weight, average particle size approximately 60 nm,
Porosity 37% by volume, refractive index 1.25)
(E)-3: Hollow silica isopropanol dispersion sol
(JGC Catalysts and Chemicals Co., Ltd., solid content 20% by weight, average particle size approximately 75 nm,
Porosity 46% by volume, refractive index 1.21)
(E)-4: Hollow silica PGMEA dispersion sol
(JGC Catalysts and Chemicals Co., Ltd., solid content 20% by weight, average particle size approximately 75 nm,
Porosity 46% by volume, refractive index 1.25)
(E)-5: Solid silica isopropanol dispersion sol
(Nissan Chemical Co., Ltd., solid content 30% by weight, average particle size approx. 80 nm, voids
0% by volume, refractive index 1.46)

(solvent)
(F)-1: Propylene glycol monomethyl ether acetate (PGMEA)
(F)-2: Cyclohexanone (ANON)

[Example]
The photosensitive resin compositions of Examples 1 to 5 and Comparative Examples 1 and 2 were prepared in the amounts (values in parts by mass) shown in Table 1. The ingredients used in the table are as follows. Note that (F)-1 and (F)-2 do not include the solvents in (A) and (D)-4 and the solvent in (E).

[evaluation]
The photosensitive resin compositions for black resists of Examples 1 to 5 and Comparative Examples 1 and 2 were used to carry out the following evaluations.

(Creation of a cured film (light-shielding film) for evaluating development characteristics)
The photosensitive resin composition shown in Table 1 was applied using a spin coater to a 125 mm x 125 mm glass substrate "#1737" (manufactured by Corning Incorporated) (hereinafter referred to as "glass substrate") whose surface had been previously cleaned by irradiating it with ultraviolet light of 254 nm wavelength at an illuminance of 1000 mJ/ ^cm² using a low-pressure mercury lamp, so that the film thickness after heat curing would be 1.2 µm, and the substrate was prebaked at 90°C for 1 minute using a hot plate to prepare a hardened film (light-shielding film). Next, the exposure gap was adjusted to 100 µm, and a negative photomask with a line/space of 10 µm/50 µm was placed on the dried light-shielding film, and ultraviolet light of 50 mJ/ ^cm² was irradiated from an ultra-high-pressure mercury lamp with an i-line illuminance of 30 mW/ ^cm² to cause a photocuring reaction of the photosensitive portion.

Next, the exposed cured film (light-shielding film) was subjected to a development treatment at 25°C with a 0.04% potassium hydroxide solution at a shower pressure of 1 kgf/ ^cm2 for +10 seconds and +20 seconds from the development time at which a pattern began to appear (break time = BT), and then the film was washed with water sprayed at 5 kgf/ ^cm2 to remove the unexposed portions of the cured film (light-shielding film), thereby forming a cured film pattern on the glass substrate. The film was then main-cured (post-baked) at 120°C for 60 minutes using a hot air dryer, thereby obtaining cured films (light-shielding films) according to Examples 1 to 5 and Comparative Examples 1 and 2.

The cured films (light-shielding films) obtained by curing the photosensitive resin compositions for black resists of Examples 1 to 5 and Comparative Examples 1 and 2 obtained above were evaluated for the following items, and the results are shown in Table 2.

[Development characteristic evaluation]
(pattern line width)
(Evaluation method)
The pattern line width after main curing (post-baking) was measured using a length measuring microscope "XD-20" (Nikon Corporation) with a mask width of 10 μm. The pattern line width was evaluated for BT + 10 seconds and BT + 20 seconds.

(Evaluation criteria)
◯: The pattern line width is within the range of 10±2 μm. ×: The pattern line width is outside the range of 10±2 μm.

(pattern linearity)
(Evaluation method)
The 10 μm mask pattern after the main curing (post-baking) was observed using an optical microscope. The pattern linearity was evaluated for both BT+10 seconds and BT+20 seconds. A score of △ or better was considered to be acceptable.

(Evaluation criteria)
○: No jagged edges are observed at the edge of the pattern. △: Jagged edges are observed in some areas at the edge of the pattern. ×: Jagged edges are observed throughout the entire pattern.

(Preparation of cured film (light-shielding film) for optical density (OD) evaluation)
The photosensitive resin compositions shown in Tables 1 and 2 were applied using a spin coater to a 125 mm x 125 mm glass substrate "#1737" (manufactured by Corning Incorporated) (hereinafter referred to as "glass substrate") whose surface had been previously cleaned by irradiating it with ultraviolet light of 254 nm wavelength at an illuminance of 1000 mJ/ ^cm2 using a low-pressure mercury lamp, so that the film thickness after heat curing would be 1.1 μm, and the substrate was prebaked at 90°C for 1 minute using a hot plate to produce a hardened film (light-shielding film). Without covering it with a negative photomask, the substrate was irradiated with ultraviolet light of 50 mJ/ ^cm2 using an ultra-high-pressure mercury lamp with an i-line illuminance of 30 mW/ ^cm2 to carry out a photocuring reaction.

Next, the exposed cured film (light-shielding film) was developed at 25°C with a 0.05% potassium hydroxide solution at a shower pressure of 1 kgf/ ^cm2 for 60 seconds from the development time (break time = BT) at which a pattern began to appear, and then washed with water sprayed at 5 kgf/ ^cm2 to remove the unexposed portions of the cured film (light-shielding film), thereby forming a cured film pattern on the glass substrate. This was then main-cured (post-baked) at 230°C for 30 minutes using a hot air dryer, thereby obtaining cured films (light-shielding films) according to Examples 1 to 5 and Comparative Examples 1 and 2.

[Optical Density Evaluation]
(Evaluation method)
The optical density (OD) of the prepared cured film (light-shielding film) was evaluated using a Macbeth transmission densitometer. The thickness of the cured film (light-shielding film) formed on the substrate was measured, and the optical density (OD) value was divided by the film thickness to obtain OD/μm.

The optical density (OD) was calculated using the following formula (1).
Optical density (OD) = -log ₁₀ T(1)
(T indicates transmittance)

[Reflectance evaluation]
(Evaluation method)
For a substrate with a cured film (light-shielding film) prepared in the same manner as for the cured film (light-shielding film) for evaluation of optical density (OD), the reflectance of each of the cured film (light-shielding film) side and the substrate (glass substrate) side was measured at an incident angle of 2° using an ultraviolet-visible-infrared spectrophotometer "UH4150" (manufactured by Hitachi High-Tech Science Corporation).

It was confirmed that the photosensitive resin compositions for black resists of Examples 1 to 5 had reduced reflectance compared to a system without silica (Comparative Example 1). Furthermore, compared to a system using solid silica (Comparative Example 2), it was confirmed that they reduced reflectivity not only on the glass substrate side but also on the coating film (light-shielding film) side. Furthermore, the cured films (light-shielding films) obtained by curing the photosensitive resin compositions for black resists of Examples 1 to 5 all had good pattern linearity, suggesting that the hollow silica was more uniformly dispersed in the cured film compared to a system using solid silica.

The photosensitive resin composition of the present invention can provide a photosensitive resin composition for black resist that has high light-shielding properties and low reflectance, as well as a light-shielding film and a color filter using the same. Furthermore, when formed on a transparent substrate, the light-shielding film of the present invention not only reduces reflectivity on the transparent substrate side, but also on the coated surface side of the light-shielding film, making it useful as a light-shielding film for sensors in various display devices and solid-state imaging devices.

Claims (7)

(A) an unsaturated group-containing photosensitive resin having an acidic group for exhibiting alkali solubility ;
(B) a photopolymerizable monomer having at least two ethylenically unsaturated bonds;
(C) a photopolymerization initiator;
(D) at least one light-shielding component selected from a black pigment, a mixed color pigment, and a light-shielding material;
(E) silica particles;
A photosensitive resin composition for black resist, comprising:
The silica particles of the component (E) are hollow particles,
The blending ratio of the component (D) is 40 to 70 mass% based on the solid components,
However, except for those in which the blending ratio of the (E) component is 5 to 30 mass% based on the solid content,
The composition is applied to a substrate so that the film thickness after heat curing treatment is 1.1 μm, pre-baked at 90°C for 1 minute, irradiated with ultraviolet light of 50 mJ/cm2 from an ultra-high pressure mercury lamp with an i-line illuminance of 30 mW/cm2 ^to cause ^a photo-curing reaction, and then cured at 230°C for 30 minutes, resulting in a cured film having a reflectance of 7.0% or less on the cured film side.
Photosensitive resin composition for black resist. 2. The photosensitive resin composition for black resist according to claim 1, wherein the unsaturated group-containing photosensitive resin (A) is an unsaturated group-containing photosensitive resin obtained by further reacting a reaction product of an epoxy compound having two glycidyl ether groups derived from a bisphenol represented by general formula (1) with (meth)acrylic acid, with a polybasic carboxylic acid or an anhydride thereof.
(In formula (1), R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogen atom; X represents —CO—, —SO ₂ —, —C(CF ₃ ) ₂ —, —Si(CH ₃ ) 2 —, —CH ₂ —, —C(CH _{3 ) 2} —, —O—, a fluorene-9,9-diyl group represented by general formula (2) or a single bond; and 1 represents an integer of 0 to 10.)
The photosensitive resin composition for black resist according to claim 1 or 2, wherein the average particle diameter of the silica particles (E) is 40 to 100 nm. The photosensitive resin composition for black resist according to any one of claims 1 to 3, wherein the porosity of the (E) silica particles is 20% by volume or more. The photosensitive resin composition for black resist according to any one of claims 1 to 4, wherein the refractive index of the (E) silica particles is 1.10 to 1.41. A light-shielding film obtained by curing the photosensitive resin composition for black resist described in any one of claims 1 to 5. A color filter having the light-shielding film of claim 6 as a black matrix.