JP2024050147A - Photosensitive resin composition, cured product, substrate with light-blocking pattern and method for producing the same, and image display device and method for producing the same - Google Patents

Abstract

To provide a photosensitive resin composition or the like capable of imparting excellent resolution and reliability to a light-blocking pattern with high optical density.SOLUTION: A photosensitive resin composition comprises an alkali-soluble binder polymer, a photopolymerizable monomer with an ethylenically unsaturated group, a colorant, and a photopolymerization initiator. The alkali-soluble binder polymer comprises a specific structure. The alkali-soluble binder polymer has a double bond equivalent of 250-400 g/mol.SELECTED DRAWING: None

Description

This disclosure relates to a photosensitive resin composition, a cured product, a substrate with a light-shielding pattern and a method for manufacturing the same, and an image display device and a method for manufacturing the same.

Image display devices such as televisions, signage, smart watches, smartphones, AR devices, and VR devices have a plurality of color-developing parts arranged in a matrix and a light-shielding pattern that separates the plurality of color-developing parts. Such light-shielding patterns are intended to suppress crosstalk (sometimes called "color mixing") between adjacent color-developing parts, and are generally formed using a photosensitive resin composition. Specifically, the light-shielding pattern is obtained by applying a photosensitive resin composition to a substrate to form a photosensitive resin layer, partially exposing the photosensitive resin layer to light to form a partially cured layer, and developing the cured part by exposure as a pattern using a developer. For example, the following Patent Document 1 proposes that a photosensitive resin composition containing a colorant, a dispersant, an alkali-soluble resin, and a photopolymerization initiator is used as the photosensitive resin composition to impart excellent light-shielding properties to the light-shielding pattern.

International Publication No. 2015/046178

In recent years, micro LED displays have been attracting attention as a next-generation image display device. Micro LED displays use micro LEDs as the color-emitting section. Micro LEDs have high quantum efficiency, which allows for a long life and low power consumption, and as they are self-emitting elements, they enable a wide viewing angle and high brightness, so they are expected to be used in micro LED displays.

However, the photosensitive resin composition described in Patent Document 1 has the following problems.
That is, when the photosensitive resin composition described in the above Patent Document 1 is used to form a light-shielding pattern on a substrate, if the color-developing part is a micro LED, the light-shielding pattern has a high optical density, and there is room for improvement in terms of resolution. Also, when the photosensitive resin composition described in the above Patent Document 1 is used to form a light-shielding pattern having a high optical density on a substrate, there is room for improvement in terms of suppressing a decrease in the thickness of the light-shielding pattern when the light-shielding pattern is left under high temperature and high humidity, that is, in terms of reliability.

The present disclosure has been made in consideration of the above problems, and aims to provide a photosensitive resin composition, a cured product, a substrate with a light-shielding pattern and a method for manufacturing the same, and an image display device and a method for manufacturing the same, which can provide excellent resolution and reliability in a light-shielding pattern having a high optical density.

In order to solve the above problems, one aspect of the present disclosure provides a photosensitive resin composition, a cured product, a substrate with a light-shielding pattern and a method for producing the same, and an image display device and a method for producing the same, as described in the following [1] to [14].
[1] A photosensitive resin composition comprising an alkali-soluble binder polymer, a photopolymerizable monomer having an ethylenically unsaturated group, a colorant, and a photopolymerization initiator, wherein the alkali-soluble binder polymer comprises a structural unit (a) represented by the following formula (1), a structural unit (b) represented by the following formula (2), a structural unit (c) represented by the following formula (3), and a structural unit (d) represented by the following formula (4), and the alkali-soluble binder polymer has a double bond equivalent of 250 to 400 g/mol.

(In the formula (1), ^R1 represents a hydrogen atom or a methyl group, and X represents an alicyclic hydrocarbon group which may have a substituent.)

(In the formula (2), ^R2 represents a hydrogen atom or a methyl group, and Y represents an aromatic group which may have a substituent.)

(In the formula (3), ^R3 represents a hydrogen atom or a methyl group.)

(In the formula (4), ^R4 and ^R5 each independently represent a hydrogen atom or a methyl group.)
[2] The photosensitive resin composition according to [1], wherein the alkali-soluble binder polymer has a solid content acid value of 25 to 125 mg KOH/g.
[3] The photosensitive resin composition according to [1] or [2], further comprising a polyfunctional thiol compound, the polyfunctional thiol compound having three or more mercapto groups in one molecule.
[4] The photosensitive resin composition according to any one of [1] to [3], wherein the content of the colorant in the total solid content is 15 mass% or less.
[5] The photosensitive resin composition according to any one of [1] to [4], wherein the photopolymerizable monomer has three or more functional groups in one molecule, and the three or more functional groups include the ethylenically unsaturated group and a hydroxyl group.
[6] The photosensitive resin composition according to any one of [1] to [5], wherein the colorant is an organic pigment.
[7] The photosensitive resin composition according to any one of [1] to [6], wherein the photopolymerization initiator includes an acylphosphine oxide-based photopolymerization initiator.
[8] A cured product obtained by curing the photosensitive resin composition according to any one of [1] to [7].
[9] A method for producing a substrate having a light-shielding pattern, comprising: a photosensitive resin layer forming step of forming a photosensitive resin layer on a substrate using the photosensitive resin composition according to any one of [1] to [7]; an exposure step of exposing the photosensitive resin layer provided on the substrate to light to form a partially cured layer; a heating step of heating the partially cured layer; and a development step of forming a light-shielding pattern by alkaline development of the partially cured layer.
[10] The method for producing a substrate having a light-shielding pattern according to [9], wherein the height of the photosensitive resin layer from the substrate is 5.0 μm or more.
[11] A substrate having a light-shielding pattern, obtained by the method for producing a substrate having a light-shielding pattern according to [9] or [10].
[12] An image display device comprising the substrate having a light-shielding pattern according to [11].
[13] A method for manufacturing an image display device, comprising: a substrate having a light-shielding pattern forming step of forming a substrate having a light-shielding pattern by the method for manufacturing a substrate having a light-shielding pattern described in [9] or [10]; and a micro LED mounting step of mounting micro LEDs on the substrate.
[14] A manufacturing method for an image display device, comprising: a micro LED formation step of forming a micro LED on the substrate; and a light-shielding patterned substrate formation step of forming a light-shielding patterned substrate by the manufacturing method for a substrate having a light-shielding pattern described in [9] or [10].

The photosensitive resin composition disclosed herein can provide excellent resolution and reliability in light-shielding patterns with high optical density.

The reason why the photosensitive resin composition of the present disclosure provides the above-mentioned effects is presumed to be as follows.
That is, when the photosensitive resin composition of the present disclosure, which includes an alkali-soluble binder polymer, a photopolymerizable monomer having an ethylenically unsaturated group, a photopolymerization initiator, and a colorant, is applied onto a substrate to form a photosensitive resin layer, and the photosensitive resin layer is partially exposed from the opposite side of the substrate, light sufficiently reaches the portion of the exposed portion of the photosensitive resin layer that is far from the substrate. Therefore, in the presence of a photopolymerization initiator, the alkali-soluble binder polymer and the photopolymerizable monomer, and the photopolymerizable monomers react with each other to sufficiently harden. On the other hand, if the concentration of the colorant in the photosensitive resin layer is high and the thickness of the photosensitive resin layer is large, the light does not easily reach the portion of the exposed portion of the photosensitive resin layer that is close to the substrate due to the presence of the colorant. Therefore, even in the presence of a photopolymerization initiator, the reaction between the alkali-soluble binder polymer and the photopolymerizable monomer, and the reaction between the photopolymerizable monomers are unlikely to occur, and hardening is likely to be insufficient during exposure. However, when the partially cured layer obtained after the exposure of the photosensitive resin layer is heated, the reaction between the alkali-soluble binder polymer and the photopolymerizable monomer and the reaction between the photopolymerizable monomers themselves proceed moderately even after the exposure because the double bond equivalent of the binder polymer is 250 to 400 g/mol, making it easier to cure. As a result, the photosensitive resin layer is cured uniformly along its thickness direction. Therefore, when the partially cured layer obtained after the exposure of the photosensitive resin layer is developed with an alkaline developer, the non-cured portion is dissolved by dissolving the alkali-soluble binder polymer in the alkaline developer, and the cured portion due to the exposure is suppressed from dissolving or swelling with the developer due to insufficient curing. As a result, excellent resolution is obtained in the obtained light-shielding pattern. In addition, since the alkali-soluble binder polymer has a double bond equivalent of 250 to 400 g/mol and has the above-mentioned structural units (a), (b), (c), and (d), it is appropriately crosslinked by exposure to light, and therefore even if the light-shielding pattern is placed in a high-temperature, high-humidity environment, a decrease in the film thickness of the light-shielding pattern is suppressed. From the above, it is speculated that the above effects can be obtained by the photosensitive resin composition of the present disclosure.

In addition, according to the manufacturing method of a substrate with a light-shielding pattern described above in [9], it is possible to manufacture a substrate with a light-shielding pattern that has excellent resolution and reliability in a light-shielding pattern having a high optical density.

Furthermore, according to the manufacturing method of the image display device of [12] above, a substrate with a light-shielding pattern can be manufactured by the manufacturing method of the substrate with a light-shielding pattern, which has excellent resolution and reliability in a light-shielding pattern with high optical density. Therefore, in an image display device having a light-shielding pattern and micro-LEDs on a substrate, crosstalk due to light from adjacent micro-LEDs can be suppressed, and the mounting density of the micro-LEDs can be improved. As a result, an image display device with high image quality and high resolution can be manufactured.

Furthermore, according to the manufacturing method of the image display device described above in [13], a substrate with a light-shielding pattern having excellent resolution and reliability in a light-shielding pattern with high optical density can be manufactured by the manufacturing method of the substrate with a light-shielding pattern. Therefore, in an image display device having a light-shielding pattern and micro-LEDs on a substrate, crosstalk due to light from adjacent micro-LEDs is suppressed, and the light-shielding pattern can be formed in accordance with the micro-LEDs to be formed. As a result, an image display device with high image quality and high resolution can be manufactured.

The present disclosure provides a photosensitive resin composition that can provide excellent resolution and reliability in a light-shielding pattern having a high optical density, a cured product, a substrate with a light-shielding pattern and a method for manufacturing the same, and an image display device and a method for manufacturing the same.

FIG. 2 is a partial cross-sectional view showing a photosensitive resin layer forming step in an embodiment of a method for producing a substrate having a light-shielding pattern according to the present disclosure. 1 is a partial cross-sectional view showing an exposure step of an embodiment of a method for producing a substrate having a light-shielding pattern according to the present disclosure. 3 is a partial cross-sectional view showing a second laminate obtained in the exposure step of FIG. 2. 1 is a partial cross-sectional view showing a heating step in an embodiment of a method for producing a substrate having a light-shielding pattern according to the present disclosure. 1 is a partial cross-sectional view showing a development step of an embodiment of a method for producing a substrate having a light-shielding pattern according to the present disclosure. FIG. 6 is a plan view showing the substrate with the light-shielding pattern of FIG. 5 . 1 is a partial cross-sectional view showing a micro LED mounting step in an embodiment of a manufacturing method for an image display device according to the present disclosure. FIG.

Hereinafter, the embodiments for carrying out the present disclosure will be described in detail, with reference to the drawings as necessary. However, the present disclosure is not limited to the following embodiments. In this specification, "(meth)acrylic acid" means acrylic acid or methacrylic acid, and "(meth)acrylate" means acrylate or the corresponding methacrylate.

<Photosensitive resin composition and cured product thereof>
The photosensitive resin composition of the present disclosure contains (A) an alkali-soluble binder polymer (hereinafter, sometimes referred to as component (A)), (B) a photopolymerizable monomer having an ethylenically unsaturated group (hereinafter, sometimes referred to as component (B)), (C) a colorant (hereinafter, sometimes referred to as component (C)), and (D) a photopolymerization initiator (hereinafter, sometimes referred to as component (D)). Here, the binder polymer contains a structural unit (a) represented by the following formula (1), a structural unit (b) represented by the following formula (2), a structural unit (c) represented by the following formula (3), and a structural unit (d) represented by the following formula (4), and the double bond equivalent of the binder polymer is 250 to 400 g/mol. The photosensitive resin composition may contain (E) a polyfunctional thiol compound (hereinafter, sometimes referred to as component (E)).

(In the above formula (1), ^R1 represents a hydrogen atom or a methyl group, and X represents an alicyclic hydrocarbon group which may have a substituent.)

(In the above formula (2), ^R2 represents a hydrogen atom or a methyl group, and Y represents an aromatic group which may have a substituent.)

(In the above formula (3), ^R3 represents a hydrogen atom or a methyl group.)

(In the above formula (4), ^R4 and ^R5 each independently represent a hydrogen atom or a methyl group.)
According to the photosensitive resin composition of the present disclosure, excellent resolution and reliability can be imparted to a light-shielding pattern having a high optical density formed using this photosensitive resin composition.
The cured product of the present disclosure is obtained by curing the above-mentioned photosensitive resin composition.
According to the cured product of the present disclosure, when the cured product is used as a light-shielding pattern, excellent resolution and reliability can be imparted to the light-shielding pattern having a high optical density.

(A) Alkali-Soluble Binder Polymer The alkali-soluble binder polymer contains a structural unit (a) represented by the above formula (1), a structural unit (b) represented by the above formula (2), a structural unit (c) represented by the above formula (3), and a structural unit (d) represented by the above formula (4).

X in formula (1) representing the structural unit (a) represents an optionally substituted alicyclic hydrocarbon group having 7 to 20 carbon atoms.
Examples of the substituent include halogen atoms such as fluoro, chloro and bromo, and hydroxy groups.
Examples of the alicyclic hydrocarbon group include an adamantyl group, a tricyclodecyl group, an isobornyl group, and a cyclohexyl group.
The structural unit (a) can be introduced by using an alicyclic hydrocarbon group-containing polymerizable monomer as the polymerizable monomer used when producing an alkali-soluble binder polymer by copolymerization.
The alicyclic hydrocarbon group-containing polymerizable monomer is represented, for example, by the following general formula (1A).
CH ₂ ═C(R ¹ )-COOX...(1A)

Examples of the alicyclic hydrocarbon group-containing polymerizable monomer represented by the above general formula (1A) include adamantyl (meth)acrylate, tricyclodecanyl (meth)acrylate, isobornyl (meth)acrylate, and cyclohexyl (meth)acrylate. These alicyclic hydrocarbon group-containing polymerizable monomers may be used alone or in combination of two or more.

In formula (2) representing the structural unit (b), Y represents an aromatic group which may have a substituent. The aromatic group may have an aromatic ring, and is represented, for example, by -P-Q. Here, P represents a single bond or -COO-, and Q represents an aromatic hydrocarbon group which may have a substituent.
Examples of the aromatic hydrocarbon group include aryl groups such as a phenyl group and a naphthyl group, aralkyl groups such as a benzyl group, and a styryl group.
The structural unit (b) can be introduced by using an aromatic hydrocarbon group-containing polymerizable monomer as the polymerizable monomer used when producing an alkali-soluble binder polymer by copolymerization.
The aromatic hydrocarbon group-containing polymerizable monomer is represented by the following general formula (2A).
CH ₂ ═C(R ² )—Y …(2A)

Examples of aromatic hydrocarbon group-containing polymerizable monomers represented by the above general formula (2A) include aromatic hydrocarbon group-containing (meth)acrylates such as benzyl (meth)acrylate, phenyl (meth)acrylate, and naphthyl (meth)acrylate, and aromatic vinyl compounds such as styrene. These aromatic hydrocarbon group-containing polymerizable monomers may be used alone or in combination of two or more.

The structural unit (c) can be introduced by using (meth)acrylic acid as a polymerizable monomer used when producing an alkali-soluble binder polymer by copolymerization. (Meth)acrylic acid is highly reactive and easily available.

The structural unit (d) can be introduced, for example, by using a polymerizable monomer represented by the following formula (4A) as a polymerizable monomer used when producing an alkali-soluble binder polymer.

The structural unit (d) can also be introduced by adding glycidyl (meth)acrylate to some of the carboxy groups of the structural unit (c).

The above-mentioned alkali-soluble binder polymer has an ethylenically unsaturated group. Therefore, during exposure, the alkali-soluble binder polymer reacts with the photopolymerizable monomer in the exposed portion of the photosensitive resin layer that is far from the substrate, and curing proceeds more sufficiently. Also, during heating of the partially cured layer obtained after exposure of the photosensitive resin layer, the alkali-soluble binder polymer reacts with the photopolymerizable monomer in the exposed portion of the photosensitive resin layer that is close to the substrate, and curing proceeds more sufficiently.

In the alkali-soluble binder polymer, when the sum of the above-mentioned structural units (a), (b), (c) and (d) is taken as the standard (100 mol%), the proportion of structural unit (a) is not particularly limited as long as it is greater than 0 mol%, but may be 0.1 mol% or more, 0.5 mol% or more, or 1 mol% or more. The proportion of structural unit (a) may be 30 mol% or less, 29 mol% or less, or 28 mol% or less.

In the alkali-soluble binder polymer, when the sum of the above-mentioned structural units (a), (b), (c) and (d) is taken as the standard (100 mol%), the proportion of structural unit (b) is not particularly limited as long as it is greater than 0 mol%, but may be 0.1 mol% or more, 0.5 mol% or more, or 1.0 mol% or more. The proportion of structural unit (b) may be less than 20 mol%, 19 mol% or less, or 18 mol% or less. If the proportion of structural unit (b) is less than 20 mol%, there is a tendency that the reduction in line width can be suppressed even when the light-shielding pattern is left in a high-temperature and high-humidity environment.

In the alkali-soluble binder polymer, when the sum of the above-mentioned structural units (a), structural unit (b), structural unit (c), and structural unit (d) is taken as the standard (100 mol%), the proportion of structural unit (c) is not particularly limited as long as it is greater than 0 mol%, but may be 1 mol% or more, 2 mol% or more, or 3 mol% or more. The proportion of structural unit (c) may be 35 mol% or less, 34 mol% or less, or 33 mol% or less.

In the alkali-soluble binder polymer, when the sum of the above structural units (a), (b), (c) and (d) is taken as the standard (100 mol%), the proportion of structural unit (d) is not particularly limited as long as it is within a range that allows the double bond equivalent to be in the range of 250 to 400, but may be 45 mol% or more, 47 mol% or more, or 49 mol% or more. The proportion of structural unit (d) may be 85 mol% or less, 83 mol% or less, or 81 mol% or less.

The double bond equivalent of the alkali-soluble binder polymer is 250 to 400 g/mol. When the double bond equivalent of the alkali-soluble binder polymer is 250 g/mol or more, the photosensitive resin composition is less likely to become tacky, and a useful alkali-soluble binder polymer is more likely to be obtained, compared with a case where the double bond equivalent is less than 250 g/mol. In addition, when the double bond equivalent of the alkali-soluble binder polymer is 400 g/mol or less, the resolution is higher or the reliability is higher, compared with a case where the double bond equivalent is more than 400 g/mol.
The double bond equivalent of the alkali-soluble binder polymer may be 260 g/mol or more, 270 g/mol or more, or 280 g/mol or more. The double bond equivalent of the alkali-soluble binder polymer may be 390 g/mol or less, 380 g/mol or less, or 370 g/mol or less.
The double bond equivalent of the alkali-soluble binder polymer is the mass of the polymer per mole of polymerizable unsaturated bonds, and is calculated based on the amount of monomer used.

The acid value of the solid content of the alkali-soluble binder polymer is not particularly limited, but may be 25 mgKOH/g or more, or may be 30 mgKOH/g or more. When the acid value of the solid content of the alkali-soluble binder polymer is 25 mgKOH/g or more, the resolution of the light-shielding pattern can be improved even if the exposure dose during exposure is low.
The alkali-soluble binder polymer may have an acid value of 125 mgKOH/g or less, or may have an acid value of 120 mgKOH/g or less. When the alkali-soluble binder polymer has an acid value of 125 mgKOH/g or less, the resolution of the light-shielding pattern can be further improved.
The solid content acid value means the number of milligrams of potassium hydroxide required to neutralize the acid present in 1 g of the alkali-soluble binder polymer.

The weight average molecular weight of the alkali-soluble binder polymer may be 3,000 to 30,000, 3,500 to 25,000, or 4,000 to 20,000 from the viewpoint of balancing mechanical strength and alkali developability. In terms of excellent developer resistance after exposure, the weight average molecular weight may be 4,000 or more. In terms of development time, the weight average molecular weight may be 20,000 or less. However, since the developability is also greatly affected by the solid acid value, hydroxyl value, and resin skeleton, the weight average molecular weight of the alkali-soluble binder polymer is not particularly limited to the above range.
The weight average molecular weight is a value measured by gel permeation chromatography (GPC) and converted using a calibration curve prepared using standard polystyrene.

The alkali-soluble binder polymers can be used alone or in combination of two or more.

(B) Photopolymerizable Monomer The photopolymerizable monomer has an ethylenically unsaturated group.

Examples of photopolymerizable monomers having an ethylenically unsaturated group include compounds obtained by reacting a polyhydric alcohol with an α,β-unsaturated carboxylic acid, bisphenol A-based (meth)acrylate compounds such as 2,2-bis(4-((meth)acryloxypolyethoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxypolypropoxy)phenyl)propane, and 2,2-bis(4-((meth)acryloxypolyethoxypolypropoxy)phenyl)propane, compounds obtained by reacting a glycidyl group-containing compound with an α,β-unsaturated carboxylic acid, urethane monomers such as (meth)acrylate compounds having a urethane bond, γ-chloro-β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate, β-hydroxyethyl-β'-(meth)acryloyloxyethyl-o-phthalate, β-hydroxypropyl-β'-(meth)acryloyloxyethyl-o-phthalate, and (meth)acrylic acid alkyl esters.

Examples of compounds obtained by reacting a polyhydric alcohol with an α,β-unsaturated carboxylic acid include polyethylene glycol di(meth)acrylate having 2 to 14 ethylene groups, polypropylene glycol di(meth)acrylate having 2 to 14 propylene groups, polyethylene polypropylene glycol di(meth)acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethoxy tri(meth)acrylate, and trimethylolpropane diethoxy tri(meth)acrylate. acrylate, trimethylolpropane triethoxy tri(meth)acrylate, trimethylolpropane tetraethoxy tri(meth)acrylate, trimethylolpropane pentaethoxy tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, polypropylene glycol di(meth)acrylate with 2 to 14 propylene groups, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

Examples of the urethane monomer include an addition reaction product of a (meth)acrylic monomer having a hydroxyl group at the β-position with a diisocyanate compound such as isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, or 1,6-hexamethylene diisocyanate, tris[(meth)acryloxytetraethylene glycol isocyanate]hexamethylene isocyanurate, EO-modified urethane di(meth)acrylate, and EO,PO-modified urethane di(meth)acrylate. Note that "EO" stands for ethylene oxide, and EO-modified compounds have a block structure of ethylene oxide groups. Also, "PO" stands for propylene oxide, and PO-modified compounds have a block structure of propylene oxide groups.

The number of functional groups in one molecule of the photopolymerizable monomer may be 2 or more, or 3 or more. Two or more types of photopolymerizable monomers, a photopolymerizable monomer having 2 or more functional groups and a photopolymerizable monomer having 3 or more functional groups, may be used in combination.

When the number of functional groups in one molecule of the photopolymerizable monomer is three or more, all of the three or more functional groups may be ethylenically unsaturated groups, or the three or more functional groups may further include a hydroxyl group in addition to the ethylenically unsaturated group. In this case, the developability of the partially cured layer obtained after exposure of the photosensitive resin layer is further improved. In addition, swelling of the cured portion due to exposure of the partially cured layer during development by the developer can be suppressed, and the resolution of the photosensitive resin composition can be further improved.

The number of functional groups in one molecule may be 26 or less, or 5 or less.

The photopolymerizable monomer may be any of the above compounds, either alone or in combination of two or more.

The content of the photopolymerizable monomer in the photosensitive resin composition may be 5 to 50 parts by mass, or 5 to 30 parts by mass, relative to 100 parts by mass of the total amount of the alkali-soluble binder polymer and the photopolymerizable monomer. When the content of the photopolymerizable monomer is 5 parts by mass or more, the photocurability of the photosensitive resin layer tends to be good, and when it is 50 parts by mass or less, when a photosensitive resin layer is formed on a substrate using the photosensitive resin composition, the photosensitive resin layer tends to have excellent shape retention before exposure.

(C) Colorant Examples of the colorant include pigments and dyes. The pigment may be either an organic pigment or an inorganic pigment, but may be an organic pigment. When the pigment is an organic pigment, the organic pigment can transmit ultraviolet light, so that light can reach a sufficiently deep position from the surface of the photosensitive resin layer during exposure, compared to when an inorganic pigment is used, and insufficient curing of the exposed part can be further suppressed. Therefore, dissolution or swelling of the cured part due to exposure during development can be further suppressed, and the resolution of the light-shielding pattern can be further improved. The colorant may contain two or more types.

Organic pigments include lactam black, perylene black, and aniline black.

Inorganic pigments include carbon black and titanium black.

Examples of dyes include leuco dyes.

The content of the colorant in the total solid content is not particularly limited as long as it is greater than 0% by mass, but may be 4% by mass or more, or 6% by mass or more, from the viewpoint of improving the light-shielding property of the light-shielding pattern to be formed. However, the content of the colorant in the total solid content may be 15% by mass or less, 12% by mass or less, or 4% by mass or less. When the content of the colorant in the total solid content is 15% by mass or less, the depth of light reaching from the surface can be increased during exposure of the photosensitive resin layer formed using the photosensitive resin composition, and insufficient curing of the exposed part can be suppressed. Therefore, dissolution or swelling of the cured part due to exposure during development with a developer is sufficiently suppressed. In particular, when the content of the colorant in the total solid content is 4% by mass or less, there is a tendency that the phenomenon of the thickness of the light-shielding pattern can be suppressed even after the light-shielding pattern is left under high temperature and high humidity.

(D) Photopolymerization initiator The photopolymerization initiator is a compound that initiates the reaction between the alkali-soluble binder polymer and the photopolymerizable monomer, and the reaction between the photopolymerizable monomers themselves. The photopolymerization initiator can be appropriately selected depending on the light wavelength of the exposure machine used, and known initiators such as photoradical polymerization initiators and photocationic polymerization initiators can be used. The photopolymerization initiator can be used alone or in combination of two or more types.

Examples of photoradical polymerization initiators include aromatic ketones such as benzophenone, N,N'-tetraalkyl-4,4'-diaminobenzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propanone-1, 4,4'-bis(dimethylamino)benzophenone (Michler's ketone), 4,4'-bis(diethylamino)benzophenone, and 4-methoxy-4'-dimethylaminobenzophenone, quinones such as alkylanthraquinone and phenanthrenequinone, benzoin compounds such as benzoin and alkylbenzoin, benzoin ether compounds such as benzoin alkyl ether and benzoin phenyl ether ... benzyl derivatives such as aryl dimethyl ketal; 2,4,5-triarylimidazole dimers such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, 2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer, and 2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer; N-phenylglycine, N-phenylglycine derivatives, and acridine derivatives such as 9-phenylacridine; 1-[4-(phenylthio)phenyl]-1,2-octanedione. These include oxime esters such as 2-(O-benzoyloxime), coumarin compounds such as 7-diethylamino-4-methylcoumarin, thioxanthone compounds such as 2,4-diethylthioxanthone, and acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

Among them, the acylphosphine oxide-based photopolymerization initiator has a photobleaching function, and therefore becomes less likely to absorb light after being decomposed by exposure. Therefore, during exposure, light can be allowed to reach a sufficiently deep position from the surface of the photosensitive resin layer over time, and therefore insufficient curing of the exposed portion can be suppressed. Therefore, dissolution or swelling of the cured portion due to exposure during development can be suppressed, and the resolution of the light-shielding pattern can be further improved.
The acylphosphine oxide photopolymerization initiator has an acylphosphine oxide group (>P(=O)-C(=O)- group), and examples thereof include (2,6-dimethoxybenzoyl)-2,4,6-pentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (product name: IRGACURE-TPO, manufactured by BASF Corporation), ethyl-2,4,6-trimethylbenzoylphenylphosphinenate, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (product name: IRGACURE-819, manufactured by BASF Corporation), (2,5-dihydroxyphenyl)diphenylphosphine oxide, (p-hydroxyphenyl)diphenylphosphine oxide, bis(p-hydroxyphenyl)phenylphosphine oxide, and tris(p-hydroxyphenyl)phosphine oxide.

As the photocationic polymerization initiator, an onium salt that releases a Lewis acid when irradiated with active energy rays may be used. Examples of such onium salts include aromatic sulfonium salts of Group VIIa elements, aromatic onium salts of Group VIa elements, and aromatic onium salts of Group Va elements. Specific examples include triarylsulfonium hexafluoroantimonate, triphenylphenacylphosphonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, bis-[4-(diphenylsulfonio)phenyl]sulfide bisdihexafluoroantimonate, bis-[4-(di-4'-hydroxyethoxyphenylsulfonio)phenyl]sulfide bisdihexafluoroantimonate, bis-[4-(diphenylsulfonio)phenyl]sulfide bisdihexafluorophosphate, and diphenyliodonium tetrafluoroborate.

From the viewpoint of achieving both photosensitivity and internal photocurability, the content of the photopolymerization initiator in the photosensitive resin composition may be 2.0 to 15.0 parts by mass, 3.0 to 12.0 parts by mass, or 4.0 to 10.0 parts by mass per 100 parts by mass of the total amount of the alkali-soluble binder polymer and the photopolymerizable monomer.

(E) Multifunctional thiol compound The photosensitive resin composition may further contain a multifunctional thiol compound. When the photosensitive resin layer obtained by exposing the photosensitive resin composition to light is heated, the multifunctional thiol compound causes a radical chain reaction, and the reaction between the photopolymerizable monomers and the mercapto group of the multifunctional thiol compound proceeds moderately even after exposure, making it easier to harden the photosensitive resin layer. In addition, the multifunctional thiol compound is intended to form a sufficient crosslinked structure in the exposed part of the partially cured layer, while relaxing the stress applied between the light-shielding pattern and the substrate 10, thereby maintaining the adhesion of the light-shielding pattern to the substrate and improving reliability. The multifunctional thiol compound may contain two or more mercapto groups in one molecule, may contain three or more mercapto groups, or may contain four or more mercapto groups. When the multifunctional thiol compound contains three or more mercapto groups in one molecule, the resolution of the light-shielding pattern can be further improved even if the exposure dose during exposure is low.
The number of mercapto groups in one molecule may be up to 6. In this case, the film remaining property and pattern width of the light-shielding pattern can be easily controlled.

Examples of polyfunctional thiol compounds include primary polyfunctional thiols and secondary polyfunctional thiols. Among them, secondary polyfunctional thiols have high storage stability and can suppress odors.

Examples of secondary polyfunctional thiols include pentaerythritol tetrakis(3-mercaptobutyrate), trimethylolpropane tris(3-mercaptobutyrate), and 1,3,5-tris[2-(3-mercaptobutanoyloxy)ethyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione.

Primary polyfunctional thiols include, for example, trimethylolpropane tris(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis(3-mercaptopropionate), and dipentaerythritol hexakis(3-mercaptopropionate).

The polyfunctional thiol compounds can be used alone or in combination of two or more types.

The content ratio of the polyfunctional thiol compound relative to 100 parts by mass of the total amount of the alkali-soluble binder polymer and the photopolymerizable monomer may be 0.05 to 10.0 parts by mass, 0.1 to 8.0 parts by mass, or 0.2 to 6.0 parts by mass. When the content ratio of the polyfunctional thiol compound is 0.05 to 10.0 parts by mass, it becomes easier to achieve both photosensitivity and internal photocurability.

The content ratio of the polyfunctional thiol compound relative to 100 parts by mass of the total amount of the photopolymerizable monomer and the polyfunctional thiol compound may be 1.0 part by mass or more, 3.0 parts by mass or more, or 5.0 parts by mass or more. In this case, even if the exposure dose during exposure is low, the resolution of the light-shielding pattern can be effectively improved.
The content of the polyfunctional thiol compound may be 60.0 parts by mass or less, 50.0 parts by mass or less, or 30.0 parts by mass or less. In this case, the resolution of the light-shielding pattern can be further improved, and the spread of the pattern width can also be suppressed.

(Other ingredients)
The photosensitive resin composition may further contain a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N,N-dimethylformamide, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, etc., as necessary. These may be used alone or in combination of two or more. The amount of the solvent may be appropriately determined so that the total solids concentration in the photosensitive resin composition is, for example, about 10 to 60 mass%.

The photosensitive resin composition may further contain additives such as plasticizers, fillers, defoamers, flame retardants, stabilizers, adhesion promoters, leveling agents, peeling promoters, antioxidants, fragrances, and thermal crosslinking agents, as necessary. Each of these may be used alone or in combination of two or more. The amount of these additives added may be 0.01 to 20 parts by mass each per 100 parts by mass of the total of the alkali-soluble binder polymer and the photopolymerizable monomer.

<Substrate with light-shielding pattern and method for producing same>
Next, an embodiment of a method for producing a substrate having a light-shielding pattern according to one aspect of the present disclosure will be described with reference to Fig. 1 to Fig. 6. Fig. 1, Fig. 2, Fig. 4, and Fig. 5 are schematic cross-sectional views showing a series of steps in the method for producing a substrate having a light-shielding pattern, Fig. 3 is a partial cross-sectional view showing a second laminate obtained in the exposure step of Fig. 2, and Fig. 6 is a plan view showing the substrate having a light-shielding pattern of Fig. 5.
The manufacturing method of the substrate with a light-shielding pattern of this embodiment includes a photosensitive resin layer formation step (see FIG. 1) of forming a photosensitive resin layer 20 on the substrate 10 using the photosensitive resin composition of this embodiment described above to obtain a first laminate 100, an exposure step (see FIGS. 2 and 3) of exposing the photosensitive resin layer 20 provided on the substrate 10 (partially irradiating the photosensitive resin layer 2 with light L) to form a partially cured layer 30 and obtain a second laminate 110, a heating step (see FIG. 4) of heating the partially cured layer 30 of the second laminate 110, and a development step (see FIG. 5) of alkaline-developing the partially cured layer 30 of the second laminate 110 and performing a post-curing step as necessary to form a light-shielding pattern 21 to obtain a substrate with a light-shielding pattern 120.

(Photosensitive resin layer forming process)
Examples of the substrate 10 in the photosensitive resin layer forming step include glass substrates, sapphire substrates, plastic substrates such as polycarbonate and cycloolefin polymer, and circuit substrates such as TFT or CMOS.

The height of the photosensitive resin layer 20 from the substrate 10 varies depending on the application, but from the viewpoint of achieving both coatability and photocurability, the thickness after drying may be 1 to 200 μm, or 10 to 100 μm.
However, the present disclosure is effective when the height of the photosensitive resin layer 20 from the substrate 10 is 5 μm or more, and is particularly effective when the height is 10 μm or more. When the height of the photosensitive resin layer 20 from the substrate 10 is 5 μm or more, light does not sufficiently reach the portion of the photosensitive resin layer 20 on the substrate 10 side during exposure. Even in such a case, the photosensitive resin composition of the present disclosure can be uniformly cured along the thickness direction of the photosensitive resin layer 20. However, the height of the photosensitive resin layer 20 from the substrate 10 may be 50 μm or less, or 30 μm or less, for the reason of making it easier to improve the resolution of the light-shielding pattern 21.

The photosensitive resin layer 20 can be formed by applying a solution of the above-mentioned photosensitive resin composition (coating liquid for forming a photosensitive resin layer) onto the substrate 10 and drying it. However, in this case, the amount of remaining organic solvent in the photosensitive resin layer 20 may be 2 mass % or less to prevent diffusion of the organic solvent in the subsequent process.

Coating can be performed by known methods such as roll coating, comma coating, gravure coating, air knife coating, die coating, bar coating, spray coating, and spin coating. After coating, drying to remove organic solvents and the like can be performed using a hot air convection dryer or the like at 70 to 150°C for about 1 to 30 minutes.

(Exposure process)
The exposure method in the exposure step includes a method of irradiating light (active light) imagewise through a mask M having a plurality of openings in order to irradiate a predetermined portion of the photosensitive resin layer 20 with light (active light) (see FIG. 2). As the light source of the active light, a known light source that effectively radiates ultraviolet light, visible light, etc., such as a carbon arc lamp, a mercury vapor arc lamp, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, etc., can be used. In addition, a light source that effectively radiates ultraviolet light, visible light, etc., such as an Ar ion laser or a semiconductor laser can also be used. Furthermore, a light source that effectively radiates visible light, such as a photographic flood lamp or a sun lamp, can also be used. A method of irradiating active light imagewise by a direct drawing method using a laser exposure method or the like can also be adopted. In this case, the mask M is not necessary.

The exposure dose in the exposure step varies depending on the apparatus used and the composition of the photosensitive resin layer 20, but may be 30 mJ/ ^cm2 or more, or 50 mJ/ ^cm2 or more in terms of excellent photocurability. The exposure dose in the exposure step may be 500 mJ/ ^cm2 or less, or 400 mJ/ ^cm2 or less in terms of resolution.

Exposure can be performed in air, vacuum, etc., and there are no particular limitations on the exposure atmosphere.

After exposure, the photosensitive resin layer 20 becomes a partially cured layer 30. Specifically, the exposed portion of the photosensitive resin layer 20 becomes a cured portion serving as a light-shielding pattern 21, and the unexposed portion of the photosensitive resin layer 20 becomes a non-cured portion 22 (see FIG. 3).

(Heating process)
The heating step is a step for appropriately proceeding a curing reaction between photopolymerizable monomers or between a photopolymerizable monomer and a mercapto group of a polyfunctional thiol compound in the portion of the light-shielding pattern 21 on the substrate 10 side by heating the partially cured layer 30. By heating the partially cured layer 30, the polyfunctional thiol compound causes a radical chain reaction, so that even after exposure, the reaction between photopolymerizable monomers and between a photopolymerizable monomer and a mercapto group of a polyfunctional thiol compound proceeds appropriately, facilitating curing.

When the partially cured layer 30 is heated in the heating process, a hot plate H (see FIG. 4), a box-type dryer, a reflow oven, a clean oven, or the like can be used as the heating means.

In the heating step, the temperature may be 70 to 150°C, or 85 to 130°C. The heating time may be 1 to 30 minutes, or 2 to 20 minutes.

(Developing process)
The alkaline development in the development step is carried out by a known method such as spraying, shaking immersion, brushing, scrubbing, etc., using a developer such as an alkaline aqueous solution.

The developer may be any solution capable of dissolving the alkali-soluble binder polymer, and may be, for example, an alkaline aqueous solution that is safe, stable, and easy to handle. Examples of the base in the alkaline aqueous solution include alkali hydroxides such as hydroxides of lithium, sodium, potassium, or ammonium; alkali carbonates such as carbonates or bicarbonates of lithium, sodium, potassium, or ammonium; alkali metal phosphates such as potassium phosphate and sodium phosphate; and alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate.

Alkaline aqueous solutions used for development may include 0.1 to 5% by mass tetraammonium hydroxide aqueous solution, 0.1 to 5% by mass sodium carbonate aqueous solution, 0.1 to 5% by mass potassium carbonate aqueous solution, 0.1 to 5% by mass sodium hydroxide aqueous solution, 0.1 to 5% by mass sodium tetraborate aqueous solution, etc. The pH of the alkaline aqueous solution used for development may be in the range of 9 to 11, and the temperature is adjusted according to the developability of the photosensitive resin layer 20. The alkaline aqueous solution may also contain a surfactant, a defoamer, a small amount of an organic solvent to promote development, etc.

An aqueous developer consisting of an alkaline aqueous solution and one or more organic solvents can be used. Here, examples of the base contained in the alkaline aqueous solution include, in addition to the above-mentioned bases, borax, sodium metasilicate, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diaminopropanol-2, and morpholine. Examples of the organic solvent include diacetone alcohol, acetone, ethyl acetate, alkoxyethanol having an alkoxy group with 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether. These can be used alone or in combination of two or more.

If necessary, two or more of the above-mentioned developers may be used in combination.

Examples of the developing method include a dipping method, a paddle method, a spray method, brushing, scrubbing, etc. Among these, when the high pressure spray method is used, the resolution of the light-shielding pattern is improved.
The development time is not particularly limited, and may be, for example, 3 seconds or more, or 5 seconds or more. When the development time is 5 seconds or more, overdevelopment is unlikely to occur, and manufacturing variations in the line width and thickness of the light-shielding pattern are reduced. The development time may be 300 seconds or less, or 200 seconds or less.
6 is a plan view showing the substrate 120 with a light-shielding pattern obtained by the development process. As shown in Fig. 6, the light-shielding pattern 21 has a plurality of openings (through holes). S in Fig. 6 represents the width of the opening, i.e., the space width, and L represents the line width of the light-shielding pattern 21.

(Post-curing process)
The post-curing step is a step of curing the cured portion after development.
The exposure method in the post-curing step includes a method of irradiating the cured portion with light (actinic rays). The light source of the actinic rays can be the same as the light source used in the exposure step.

The exposure dose in the post-curing step varies depending on the apparatus used and the composition of the curing part, but in terms of excellent photocurability, it may be 100 mJ/ ^cm2 or more, or 300 mJ/ ^cm2 or more. The exposure dose in the post-curing step may be 10,000 mJ/ ^cm2 or less, or 5,000 mJ/ ^cm2 or less.

The post-curing process can be carried out in air, in a vacuum, or the like, and there are no particular limitations on the atmosphere in which the post-curing process is carried out.

If a post-curing process is performed, the cured portion that is further cured by the post-curing process will ultimately become the light-shielding pattern 21.

<Image display device and manufacturing method thereof>
Next, an embodiment of the image display device and the manufacturing method thereof according to the present disclosure will be described with reference to Fig. 7. Fig. 7 is a partial cross-sectional view showing a micro LED mounting step in the embodiment of the manufacturing method of the image display device according to the present disclosure.

The manufacturing method of the image display device of this embodiment includes a substrate with a light-shielding pattern forming process in which a substrate with a light-shielding pattern 120 is formed by the manufacturing method of a substrate with a light-shielding pattern described above, and a micro LED mounting process in which micro LEDs 40 are mounted as light-emitting elements on the substrate 10 (see FIG. 7). The image display device 200 is obtained by the manufacturing method of the image display device described above.

In the process of forming a substrate with a light-shielding pattern, a circuit board is used as the substrate 10. The micro LEDs 40 are mounted on the circuit board and electrically connected to enable the micro LEDs 40 to be turned on and off. The colorant contained in the photosensitive resin composition used to form the light-shielding pattern 21 may be black from the viewpoint of further suppressing crosstalk. Furthermore, the manufacturing method of the image display device of this embodiment is effective when the height of the photosensitive resin layer 20 from the substrate 10 is 5 μm or more, and is particularly effective when it is 10 μm or more. In an image display device having a light-shielding pattern 21 and micro LEDs 40 on the substrate 10, when the height of the micro LEDs 40 mounted on the substrate 10 is 5 μm or more, crosstalk due to light from adjacent micro LEDs 40 can be sufficiently suppressed.

In the micro-LED mounting process, micro-LEDs 40 refer to tiny LEDs (semiconductor light-emitting diodes), elements for LED fabrication, materials for LED fabrication, parts incorporating LEDs, LED wafers, etc. Examples include LED elements using gallium nitride, indium gallium nitride, silicon, etc.

The shape of the micro LED 40 is not particularly limited, but examples of shapes include a square, rectangle, rhombus, trapezoid, polygon, or a shape with a curved surface such as a circle, ellipse, or arc in the shape of the main surface. The micro LED 40 may also have a shape with projections and recesses in the thickness direction. The size of the micro LED 40 may be, for example, a square main surface with a side length of 0.1 to 2000 μm, and a rectangular main surface with a long side length of 0.2 μm to 2000 μm and a short side length of 0.1 to 1500 μm. The thickness of the micro LED 40 is, for example, 0.1 to 20 μm.

The micro LEDs 40 are disposed in openings formed in the light-shielding pattern 21 and are electrically connected to the substrate 10. The micro LEDs 40 may be micro LEDs formed on other substrates such as a sapphire substrate and cut out individually. The micro LEDs 40 may be appropriately selected from micro LEDs that emit blue light, micro LEDs that emit red light, and micro LEDs that emit green light. In this case, the height of the micro LEDs 40 from the substrate 10 may be equal to or less than the height of the light-shielding pattern 21 from the substrate 10. In this case, crosstalk caused by light from adjacent micro LEDs 40 can be further suppressed.

The process of forming a substrate with a light-shielding pattern and the process of mounting the micro-LEDs may be performed in such a manner that the micro-LED mounting process is performed after the process of forming a substrate with a light-shielding pattern, or the micro-LED mounting process is performed after the process of forming a substrate with a light-shielding pattern. In addition, a color filter may be provided on the side of the micro-LEDs 40 opposite the substrate 10 as necessary.

According to the manufacturing method of the image display device of this embodiment, the manufacturing method of the substrate with a light-shielding pattern makes it possible to manufacture a substrate with a light-shielding pattern 120 having excellent resolution and reliability in the light-shielding pattern 21. Therefore, in the image display device 200 having the light-shielding pattern 21 and the micro-LEDs 40 on the substrate 10, crosstalk due to light from adjacent micro-LEDs 40 is suppressed, and the mounting density of the micro-LEDs 40 can also be improved. As a result, an image display device 200 with high image quality and high resolution can be manufactured.

The manufacturing method of the image display device may include a micro LED forming process for forming micro LEDs 40 on the substrate 10, and a light-shielding patterned substrate forming process for forming a light-shielding patterned substrate 120 by the above-mentioned method for manufacturing a light-shielding patterned substrate.

According to the manufacturing method of the image display device of the present disclosure, a substrate with a light-shielding pattern can be manufactured with a light-shielding pattern having excellent resolution and reliability in a light-shielding pattern with high optical density. Therefore, in an image display device having a light-shielding pattern and micro-LEDs on a substrate, crosstalk due to light from adjacent micro-LEDs is suppressed, and the light-shielding pattern can be formed in accordance with the micro-LEDs to be formed. As a result, an image display device with high image quality and high resolution can be manufactured.

In the above embodiment, an image display device having a substrate with a light-shielding pattern and a micro LED as a light-emitting element is given as an image display device of the present disclosure. However, the image display device of the present disclosure may be an image display device including the substrate with the light-shielding pattern, for example, an image display device including a substrate with a light-shielding pattern and an organic light-emitting element or a quantum dot light-emitting element as a light-emitting element.

The present disclosure will be explained in more detail below with examples and comparative examples, but the present disclosure is not limited to the following examples.

<Preparation of Alkali-Soluble Binder Polymer Solution>
Alkali-soluble binder polymer solutions (hereinafter sometimes simply referred to as "binder polymer solutions") 1 to 16 were prepared as follows. The structural units 1 to 8 of the alkali-soluble binder polymer (hereinafter sometimes simply referred to as "binder polymer") are as follows. Here, structural unit 1 is included in structural unit (a), structural unit 2 is included in structural unit (b), structural unit 3 is included in structural unit (c), and structural units 4 and 6 are included in structural unit (d).

(Binder polymer solution 1)
To a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer, and a gas inlet tube, 180.1 g of propylene glycol monomethyl ether (PGME) was added as a solvent, and the mixture was stirred while replacing the gas in the flask with nitrogen gas and heated to 120°C.
Next, a monomer mixture consisting of 39.6 g (0.18 mol) of tricyclodecanyl methacrylate, 3.52 g (0.02 mol) of benzyl methacrylate, and 68.8 g (0.80 mol) of methacrylic acid was prepared by adding 5.93 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O). This mixture of monomers and polymerization initiator was dropped into the flask from the dropping funnel over 1 hour. After the dropwise addition, the liquid in the flask was stirred at 120 ° C for another 2 hours to carry out a copolymerization reaction, and a precursor solution of binder polymer 1 was synthesized. Thereafter, the gas in the flask was replaced with air, and 88.0 g (0.62 mol) of glycidyl methacrylate, 0.6 g of triphenylphosphine (catalyst), and 0.6 g of methylhydroquinone (polymerization inhibitor) were added to the precursor solution of binder polymer 1. Then, the reaction was continued at 110 ° C for 10 hours to obtain a resin solution. The binder polymer 1 contained in this resin solution had a weight average molecular weight of 18,500, a double bond equivalent of 340 g/mol, and a glass transition temperature (Tg) of 58.7° C. In addition, the proportions of the structural units 1 to 8 in the binder polymer 1 were as shown in Table 1, with the total of all structural units 1 to 8 being taken as the standard (100 mol%).
PGME was further added to this resin solution to prepare a binder polymer solution 1 (solid content concentration: 46.3% by mass) as a binder polymer solution. At this time, the binder polymer solution 1 was prepared so that the binder polymer 1 and PGME were mixed in the mass ratio shown in Table 3.
The solid content means the heating residue when the binder polymer solution is heated at 130° C. for 2 hours, and the main component of the solid content is binder polymer 1. The resin acid value of this binder polymer solution 1 was 28.1 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 1 was 60.7 KOHmg/g.

(Binder polymer solution 2)
A resin solution was obtained in the same manner as in binder polymer solution 1, except that t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O) was changed from 5.93 g to 8.62 g. The weight average molecular weight of binder polymer 2 contained in this resin solution was 13,100, the double bond equivalent was 340 g/mol, and the glass transition temperature (Tg) of binder polymer 2 was 58.7° C. In addition, the proportions of each of the structural units 1 to 8 in binder polymer 2 were as shown in Table 1, assuming the total of all structural units 1 to 8 as the standard (100 mol%).
PGME was further added to this resin solution to prepare binder polymer solution 2 (solid content concentration 49.1% by mass) as a binder polymer solution. At this time, binder polymer solution 2 was prepared so that binder polymer 2 and PGME were mixed in the mass ratio shown in Table 3. The resin acid value of this binder polymer solution 2 was 29.9 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 2 was 58.9 KOHmg/g.

(Binder polymer solution 3)
To a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 180.1 g of PGME was added as a solvent, and the mixture was stirred while replacing the liquid in the flask with nitrogen gas, and the temperature was raised to 120°C.
Next, a monomer mixture consisting of 39.6 g (0.18 mol) of tricyclodecanyl methacrylate, 3.52 g (0.02 mol) of benzyl methacrylate, and 68.8 g (0.8 mol) of methacrylic acid was prepared by adding 7.39 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O). This mixture of monomers and polymerization initiator was dropped into the flask from the dropping funnel over 1 hour. After the dropwise addition, the liquid in the flask was stirred at 120° C. for another 2 hours to carry out a copolymerization reaction, and a precursor solution of binder polymer 3 was synthesized. Thereafter, the gas in the flask was replaced with air, and 102.24 g (0.72 mol) of glycidyl methacrylate, 0.64 g of triphenylphosphine (catalyst), and 0.64 g of methylhydroquinone (polymerization inhibitor) were added to the precursor solution of binder polymer 3. Thereafter, the reaction was continued for 10 hours at 110° C. to obtain a resin solution. The weight average molecular weight of binder polymer 3 contained in this resin solution was 15,500, the double bond equivalent was 310 g/mol, and the glass transition temperature (Tg) of binder polymer 3 was 50.5° C. In addition, the proportions of each of the structural units 1 to 8 in binder polymer 3 were as shown in Table 1, assuming the total of all structural units 1 to 8 as the standard (100 mol%).
PGME was further added to this solution of binder polymer 3 to prepare binder polymer solution 3 (solid content concentration 48.9 mass %) as a binder polymer solution. At this time, binder polymer solution 3 was prepared so that binder polymer 3 and PGME were mixed in the mass ratio shown in Table 3. Furthermore, the resin acid value of this binder polymer solution 3 was 14.9 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 3 was 30.5 KOHmg/g.

(Binder polymer solution 4)
A resin solution was obtained in the same manner as for binder polymer solution 3, except that t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O) was changed from 7.39 g to 9.74 g. Binder polymer 4 contained in this resin solution had a weight average molecular weight of 12,500, a double bond equivalent of 310 g/mol, and a glass transition temperature (Tg) of 50.5° C. In addition, the proportions of each of the structural units 1 to 8 in binder polymer 4 were as shown in Table 1, assuming the total of all structural units 1 to 8 as the standard (100 mol%).
PGME was further added to this resin solution to prepare binder polymer solution 4 (solid content concentration 51.1% by mass). At this time, binder polymer solution 4 was prepared so that binder polymer 4 and PGME were mixed in the mass ratio shown in Table 3. The resin acid value of this binder polymer solution 4 was 16.2 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 4 was 31.7 KOHmg/g.

(Binder polymer solution 5)
A resin solution was obtained in the same manner as for binder polymer solution 3, except that t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O) was changed from 7.39 g to 14.55 g. Binder polymer 5 contained in this resin solution had a weight average molecular weight of 9,300, a double bond equivalent of 310 g/mol, and a glass transition temperature (Tg) of 50.5° C. In addition, the proportions of each of the structural units 1 to 8 in binder polymer 5 were as shown in Table 1, assuming the total of all structural units 1 to 8 as the standard (100 mol%).
PGME was further added to this resin solution to prepare binder polymer solution 5 (solid content concentration 53.2 mass%) as a binder polymer solution. At this time, binder polymer solution 5 was prepared so that binder polymer 5 and PGME were mixed in the mass ratio shown in Table 3. The resin acid value of this binder polymer solution 5 was 16.4 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 5 was 30.8 KOHmg/g.

(Binder polymer solution 6)
To a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 180.1 g of PGME was added as a solvent, and the mixture was heated to 120° C. while stirring and replacing the gas in the flask with nitrogen gas.
Next, a monomer mixture consisting of 4.40 g (0.02 mol) of tricyclodecanyl methacrylate, 31.68 g (0.18 mol) of benzyl methacrylate, and 68.8 g (0.8 mol) of methacrylic acid was prepared by adding 5.56 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O). This mixture of monomers and polymerization initiator was dropped into the flask from the dropping funnel over 1 hour. After the dropping was completed, the liquid in the flask was stirred for another 2 hours at 120° C. to carry out a copolymerization reaction, and a precursor solution of binder polymer 6 was synthesized. Thereafter, the gas in the flask was replaced with air, and 88.04 g (0.62 mol) of glycidyl methacrylate, 0.6 g of triphenylphosphine (catalyst), and 0.6 g of methylhydroquinone (polymerization inhibitor) were added to the precursor solution of binder polymer 6. Thereafter, the reaction was continued for 10 hours at 110° C. to obtain a resin solution. The weight average molecular weight of binder polymer 6 contained in this resin solution was 20,100, the double bond equivalent was 320 g/mol, and the glass transition temperature (Tg) of binder polymer 6 was 43.1° C. In addition, the proportions of each of the structural units 1 to 8 in binder polymer 6 were as shown in Table 1, assuming the total of all structural units 1 to 8 as the standard (100 mol%).
PGME was further added to this resin solution to prepare binder polymer solution 6 (solid content concentration 46.1 mass%) as a binder polymer solution. At this time, binder polymer solution 6 was prepared so that binder polymer 6 and PGME were mixed in the mass ratio shown in Table 4. Furthermore, the resin acid value of this binder polymer solution 6 was 31.0 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 6 was 67.2 KOHmg/g.

(Binder polymer solution 7)
To a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 180.1 g of PGME was added as a solvent, and the mixture was heated to 120° C. while stirring and replacing the gas in the flask with nitrogen gas.
Next, a monomer mixture consisting of 39.6 g (0.18 mol) of tricyclodecanyl methacrylate, 3.52 g (0.02 mol) of benzyl methacrylate, and 68.8 g (0.8 mol) of methacrylic acid was prepared by adding 5.60 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O). This mixture of monomers and polymerization initiator was dropped into the flask from the dropping funnel over 1 hour. After the dropwise addition, the liquid in the flask was stirred for another 2 hours at 120 ° C. to carry out a copolymerization reaction, and a precursor solution of binder polymer 7 was synthesized. Thereafter, the gas in the flask was replaced with air, and 71.00 g (0.50 mol) of glycidyl methacrylate, 0.6 g of triphenylphosphine (catalyst), and 0.6 g of methylhydroquinone (polymerization inhibitor) were added to the precursor solution of binder polymer 7. Then, the reaction was continued for 10 hours at 110 ° C. to obtain a resin solution. The binder polymer 7 contained in this resin solution had a weight average molecular weight of 17,700, a double bond equivalent of 380 g/mol, and a glass transition temperature (Tg) of 70.9° C. The proportions of the structural units 1 to 8 in the binder polymer were as shown in Table 1, with the total of all structural units 1 to 8 being taken as the standard (100 mol%).
PGME was further added to this resin solution to prepare binder polymer solution 7 (solid content concentration 42.8% by mass) as a binder polymer solution. At this time, binder polymer solution 7 was prepared so that binder polymer 7 and PGME were mixed in the mass ratio shown in Table 4. The resin acid value of this binder polymer solution 7 was 43.4 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 7 was 101.4 KOHmg/g.

(Binder polymer solution 8)
To a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 180.1 g of PGME was added as a solvent, and the mixture was heated to 120° C. while stirring and replacing the gas in the flask with nitrogen gas.
Next, a monomer mixture consisting of 61.6 g (0.28 mol) of tricyclodecanyl methacrylate, 3.52 g (0.02 mol) of benzyl methacrylate, and 60.2 g (0.7 mol) of methacrylic acid was prepared by adding 5.64 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O). This mixture of monomers and polymerization initiator was dropped into the flask from the dropping funnel over 1 hour. After the dropwise addition, the liquid in the flask was stirred for another 2 hours at 120 ° C. to carry out a copolymerization reaction, and a precursor solution of binder polymer 8 was synthesized. Thereafter, the gas in the flask was replaced with air, and 73.84 g (0.52 mol) of glycidyl methacrylate, 0.6 g of triphenylphosphine (catalyst), and 0.6 g of methylhydroquinone (polymerization inhibitor) were added to the precursor solution of binder polymer 8. Then, the reaction was continued for 10 hours at 110 ° C. to obtain a resin solution. The binder polymer 8 contained in this resin solution had a weight average molecular weight of 14,600, a double bond equivalent of 400 g/mol, and a glass transition temperature (Tg) of 73.0° C. The proportions of the structural units 1 to 8 in the binder polymer were as shown in Table 1, with the total of all structural units 1 to 8 being taken as the standard (100 mol%).
PGME was further added to this resin solution to prepare binder polymer solution 8 (solid content concentration 46.0 mass%) as a binder polymer solution. At this time, binder polymer solution 8 was prepared so that binder polymer 8 and PGME were mixed in the mass ratio shown in Table 4. Furthermore, the resin acid value of this binder polymer solution 8 was 28.5 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 8 was 62.0 KOHmg/g.

(Binder Polymer Solution 9)
To a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 180.1 g of PGME was added as a solvent, and the mixture was heated to 120° C. while stirring and replacing the gas in the flask with nitrogen gas.
Next, a monomer mixture consisting of 2.20 g (0.01 mol) of tricyclodecanyl methacrylate, 1.76 g (0.01 mol) of benzyl methacrylate, and 84.28 g (0.98 mol) of methacrylic acid was prepared by adding 7.77 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O). This mixture of monomers and polymerization initiator was dropped into the flask from the dropping funnel over 1 hour. After the dropwise addition, the liquid in the flask was stirred at 120° C. for another 2 hours to carry out a copolymerization reaction, and a precursor solution of binder polymer 9 was synthesized. Thereafter, the gas in the flask was replaced with air, and 73.84 g (0.52 mol) of glycidyl methacrylate, 0.6 g of triphenylphosphine (catalyst), and 0.6 g of methylhydroquinone (polymerization inhibitor) were added to the precursor solution of binder polymer 9. Thereafter, the reaction was continued for 10 hours at 110° C. to obtain a resin solution. The weight average molecular weight of binder polymer 9 contained in this resin solution was 16,500, the double bond equivalent was 270 g/mol, and the glass transition temperature (Tg) of binder polymer 9 was 36.9° C. The proportions of each of the structural units 1 to 8 in the binder polymer were as shown in Table 1, assuming the total of all structural units 1 to 8 as the standard (100 mol%).
PGME was further added to this resin solution to prepare binder polymer solution 9 (solid content concentration 44.1 mass%) as a binder polymer solution. At this time, binder polymer solution 9 was prepared so that binder polymer 9 and PGME were mixed in the mass ratio shown in Table 4. Furthermore, the resin acid value of this binder polymer solution 9 was 29.1 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 9 was 66.0 KOHmg/g.

(Binder Polymer Solution 10)
To a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 180.1 g of PGME was added as a solvent, and the mixture was heated to 120° C. while stirring and replacing the gas in the flask with nitrogen gas.
Next, a monomer mixture consisting of 39.6 g (0.18 mol) of tricyclodecanyl methacrylate, 3.52 g (0.02 mol) of benzyl methacrylate, and 68.8 g (0.8 mol) of methacrylic acid was prepared by adding 3.36 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O). This mixture of monomers and polymerization initiator was dropped into the flask from the dropping funnel over 1 hour. After the dropwise addition, the liquid in the flask was stirred at 120 ° C for another 2 hours to carry out a copolymerization reaction, and a precursor solution of binder polymer 10 was synthesized. Thereafter, the gas in the flask was replaced with air, and 41.18 g (0.29 mol) of glycidyl methacrylate, 0.45 g of triphenylphosphine (catalyst), and 0.45 g of methylhydroquinone (polymerization inhibitor) were added to the precursor solution of binder polymer 10. Thereafter, the reaction was continued for 10 hours at 110° C. to obtain a resin solution. The weight average molecular weight of binder polymer 10 contained in this resin solution was 18,500, the double bond equivalent was 550 g/mol, and the glass transition temperature (Tg) of binder polymer 10 was 102.4° C. In addition, the proportions of each of the structural units 1 to 8 in the binder polymer were as shown in Table 2, assuming the total of all structural units 1 to 8 as the standard (100 mol%).
PGME was further added to this resin solution to prepare binder polymer solution 10 (solid content concentration 39.3 mass%) as a binder polymer solution. At this time, binder polymer solution 10 was prepared so that binder polymer 10 and PGME were mixed in the mass ratio shown in Table 5. The resin acid value of this binder polymer solution 10 was 75.6 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 10 was 192.4 KOHmg/g.

(Binder Polymer Solution 11)
To a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 180.1 g of PGME was added as a solvent, and the mixture was heated to 120° C. while stirring and replacing the gas in the flask with nitrogen gas.
Next, a monomer mixture consisting of 39.6 g (0.18 mol) of tricyclodecanyl methacrylate, 3.52 g (0.02 mol) of benzyl methacrylate, and 68.8 g (0.8 mol) of methacrylic acid was prepared by adding 5.15 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O). This mixture of monomers and polymerization initiator was dropped into the flask from the dropping funnel over 1 hour. After the dropping was completed, the liquid in the flask was stirred for another 2 hours at 120° C. to carry out a copolymerization reaction, and a precursor solution of binder polymer 11 was synthesized. Thereafter, the gas in the flask was replaced with air, and 56.80 g (0.40 mol) of glycidyl methacrylate, 0.50 g of triphenylphosphine (catalyst), and 0.50 g of methylhydroquinone (polymerization inhibitor) were added to the precursor solution of binder polymer 11. Thereafter, the reaction was continued for 10 hours at 110° C. to obtain a resin solution. The weight average molecular weight of binder polymer 11 contained in this resin solution was 17,400, the double bond equivalent was 440 g/mol, and the glass transition temperature (Tg) of binder polymer 11 was 83.8° C. The proportions of each of the structural units 1 to 8 in the binder polymer were as shown in Table 2, assuming the total of all structural units 1 to 8 as the standard (100 mol%).
PGME was further added to this resin solution to prepare binder polymer solution 11 (solid content concentration 41.9 mass%) as a binder polymer solution. At this time, binder polymer solution 11 was prepared so that binder polymer 11 and PGME were mixed in the mass ratio shown in Table 5. The resin acid value of this binder polymer solution 11 was 58.0 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 11 was 138.4 KOHmg/g.

(Binder polymer solution 12)
To a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 167.1 g of PGMEA was added as a solvent, and the mixture was heated to 120° C. while stirring and replacing the gas in the flask with nitrogen gas.
Next, a monomer mixture consisting of 66.0 g (0.3 mol) of tricyclodecanyl methacrylate, 10.4 g (0.1 mol) of styrene, and 85.2 g (0.6 mol) of glycidyl methacrylate was prepared by adding 19.4 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O). This mixture of monomers and polymerization initiator was dropped into the flask from the dropping funnel over 1 hour. After the dropwise addition, the liquid in the flask was stirred at 120° C. for another 2 hours to carry out a copolymerization reaction, and a precursor of the binder polymer 12 was produced. Thereafter, the gas in the flask was replaced with air, and 41.9 g (0.58 mol) of acrylic acid, 0.61 g of triphenylphosphine (catalyst), and 0.31 g of methylhydroquinone (polymerization inhibitor) were added to the precursor solution of the binder polymer 12. Then, the reaction was continued at 110° C. for 10 hours. Next, 68.4 g (0.45 mol) of tetrahydrophthalic anhydride was added to the flask, and the reaction was continued for 3 hours at 110° C. to obtain a resin solution. The weight average molecular weight of binder polymer 12 contained in this resin solution was 8,300, the double bond equivalent was 500 g/mol, and the glass transition temperature (Tg) of binder polymer 12 was 39.0° C. In addition, the proportions of each of the structural units 1 to 8 in the binder polymer were as shown in Table 2, assuming the total of all structural units 1 to 8 as the standard (100 mol%).
PGMEA was further added to this resin solution to prepare binder polymer solution 12 (solid content concentration 57.6 mass%) as a binder polymer solution. At this time, binder polymer solution 12 was prepared so that binder polymer 12 and PGMEA were mixed in the mass ratio shown in Table 5. Furthermore, the resin acid value of this binder polymer solution 12 was 51.6 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 12 was 89.6 KOHmg/g.

(Binder Polymer Solution 13)
To a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 167.1 g of PGMEA was added as a solvent, and the mixture was heated to 120° C. while stirring and replacing the gas in the flask with nitrogen gas.
Next, a monomer mixture consisting of 66.0 g (0.3 mol) of tricyclodecanyl methacrylate, 10.4 g (0.1 mol) of styrene, and 85.2 g (0.6 mol) of glycidyl methacrylate was prepared by adding 10.7 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O). This mixture of monomers and polymerization initiator was dropped into the flask from the dropping funnel over 1 hour. After the dropwise addition, the liquid in the flask was stirred at 120° C. for another 2 hours to carry out a copolymerization reaction, and a precursor of binder polymer 13 was produced. Thereafter, the gas in the flask was replaced with air, and 41.9 g (0.58 mol) of acrylic acid, 0.61 g of triphenylphosphine (catalyst), and 0.31 g of methylhydroquinone (polymerization inhibitor) were added to the precursor solution of binder polymer 13. Then, the reaction was continued at 110° C. for 10 hours. Next, 66.88 g (0.44 mol) of tetrahydrophthalic anhydride was added to the flask, and the reaction was continued for 3 hours at 110° C. to obtain a resin solution. The weight average molecular weight of binder polymer 13 contained in this resin solution was 14,700, the double bond equivalent was 480 g/mol, and the glass transition temperature (Tg) of binder polymer 13 was 40.0° C. In addition, the proportions of each of the structural units 1 to 8 in the binder polymer were as shown in Table 2, assuming the total of all structural units 1 to 8 as the standard (100 mol%).
PGMEA was further added to this resin solution to prepare binder polymer solution 13 (solid content concentration 53.2 mass%) as a binder polymer solution. At this time, binder polymer solution 13 was prepared so that binder polymer 13 and PGMEA were mixed in the mass ratio shown in Table 5. Furthermore, the resin acid value of this binder polymer solution 13 was 46.9 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 13 was 88.2 KOHmg/g.

(Binder Polymer Solution 14)
To a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 167.1 g of PGMEA was added as a solvent, and the mixture was heated to 120° C. while stirring and replacing the gas in the flask with nitrogen gas.
Next, a monomer mixture consisting of 66.0 g (0.3 mol) of tricyclodecanyl methacrylate, 10.4 g (0.1 mol) of styrene, and 85.2 g (0.6 mol) of glycidyl methacrylate was prepared by adding 16.16 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O). This mixture of monomers and polymerization initiator was dropped into the flask from the dropping funnel over 1 hour. After the dropwise addition, the liquid in the flask was stirred at 120° C. for another 2 hours to carry out a copolymerization reaction, and a precursor of the binder polymer 14 was produced. Thereafter, the gas in the flask was replaced with air, and 41.9 g (0.58 mol) of acrylic acid, 0.61 g of triphenylphosphine (catalyst), and 0.31 g of methylhydroquinone (polymerization inhibitor) were added to the precursor solution of the binder polymer 14. Then, the reaction was continued at 110° C. for 10 hours. Next, 41.05 g (0.27 mol) of tetrahydrophthalic anhydride was added to the flask, and the reaction was continued for 3 hours at 110° C. to obtain a resin solution. The weight average molecular weight of binder polymer 14 contained in this resin solution was 7200, the double bond equivalent was 450 g/mol, and the glass transition temperature (Tg) of binder polymer 14 was 47.6° C. The proportions of each of the structural units 1 to 8 in the binder polymer were as shown in Table 2, assuming the total of all structural units 1 to 8 as the standard (100 mol%).
PGMEA was further added to this resin solution to prepare binder polymer solution 14 (solid content concentration 57.6 mass %) as a binder polymer solution. At this time, binder polymer solution 14 was prepared so that binder polymer 14 and PGMEA were mixed in the mass ratio shown in Table 5. Furthermore, the resin acid value of this binder polymer solution 14 was 36.8 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 14 was 63.9 KOHmg/g.

(Binder Polymer Solution 15)
To a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 152.5 g of PGMEA was added as a solvent, and the mixture was heated to 120° C. while stirring and replacing the gas in the flask with nitrogen gas.
Next, a monomer mixture consisting of 66.0 g (0.30 mol) of tricyclodecanyl methacrylate, 10.4 g (0.10 mol) of styrene, and 85.2 g (0.60 mol) of glycidyl methacrylate was prepared by adding 10.3 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O). This mixture of monomers and polymerization initiator was dropped into the flask from the dropping funnel over 1 hour. After the dropwise addition, the liquid in the flask was stirred at 120° C. for another 2 hours to carry out a copolymerization reaction, and a precursor of binder polymer 15 was produced. Thereafter, the gas in the flask was replaced with air, and 41.9 g (0.58 mol) of acrylic acid, 0.61 g of triphenylphosphine (catalyst), and 0.31 g of methylhydroquinone (polymerization inhibitor) were added to the precursor solution of binder polymer 15. Then, the reaction was continued at 110° C. for 10 hours. Next, 33.00 g (0.33 mol) of succinic anhydride was added to the flask, and the reaction was continued for 3 hours at 110° C. to obtain a resin solution. The weight average molecular weight of binder polymer 15 contained in this resin solution was 15,000, the double bond equivalent was 420 g/mol, and the glass transition temperature (Tg) of binder polymer 15 was 48.4° C. In addition, the proportions of each of the structural units 1 to 8 in the binder polymer were as shown in Table 2, assuming the total of all structural units 1 to 8 as the standard (100 mol%).
PGMEA was further added to this resin solution to prepare binder polymer solution 15 (solid content concentration 53.3 mass%) as a binder polymer solution. At this time, binder polymer solution 15 was prepared so that binder polymer 15 and PGMEA were mixed in the mass ratio shown in Table 5. The resin acid value of this binder polymer solution 15 was 40.2 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 15 was 75.4 KOHmg/g.

(Binder Polymer Solution 16)
To a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 167.1 g of PGMEA was added as a solvent, and the mixture was heated to 120° C. while stirring and replacing the gas in the flask with nitrogen gas.
Next, a monomer mixture consisting of 66.0 g (0.30 mol) of tricyclodecanyl methacrylate, 23.9 g (0.23 mol) of styrene, and 66.7 g (0.47 mol) of glycidyl methacrylate was prepared by adding 17.2 g of t-butylperoxy-2-ethylhexanoate (polymerization initiator, manufactured by NOF Corporation, Perbutyl (registered trademark) O). This mixture of monomers and polymerization initiator was dropped into the flask from the dropping funnel over 1 hour. After the dropwise addition, the liquid in the flask was stirred at 120° C. for another 2 hours to carry out a copolymerization reaction, and a precursor of the binder polymer 16 was produced. Thereafter, the gas in the flask was replaced with air, and 32.8 g (0.46 mol) of acrylic acid, 0.61 g of triphenylphosphine (catalyst), and 0.31 g of methylhydroquinone (polymerization inhibitor) were added to the precursor solution of the binder polymer 16. Then, the reaction was continued at 110° C. for 10 hours. Next, 22.00 g (0.22 mol) of succinic anhydride was added to the flask, and the reaction was continued for 3 hours at 110° C. to obtain a resin solution. The weight average molecular weight of binder polymer 16 contained in this resin solution was 8100, the double bond equivalent was 420 g/mol, and the glass transition temperature (Tg) of binder polymer 16 was 60.1° C. In addition, the proportions of each of the structural units 1 to 8 in the binder polymer were as shown in Table 2, assuming the total of all structural units 1 to 8 as the standard (100 mol%).
PGMEA was further added to this resin solution to prepare binder polymer solution 16 (solid content concentration 58.4 mass%) as a binder polymer solution. At this time, binder polymer solution 16 was prepared so that binder polymer 16 and PGMEA were mixed in the mass ratio shown in Table 5. The resin acid value of this binder polymer solution 16 was 33.2 KOHmg/g, and the solid content acid value of the solid content contained in binder polymer solution 1 was 56.8 KOHmg/g.

<Measuring methods for physical properties>
The above resin acid value, solid content acid value, double bond equivalent, weight average molecular weight and glass transition temperature are values obtained by the methods described below.
(1) Resin acid value The resin acid value is the acid value of a binder polymer solution measured using a mixed indicator of bromothymol blue and phenol red in accordance with JIS K6901 5.3.2. The resin acid value means the number of milligrams of potassium hydroxide required to neutralize the acidic components contained in 1 g of the binder polymer solution.
(2) Acid Value of Solid Content The acid value of solid content is a value calculated by the following formula.
Acid value of solid content=100×acid value of resin/(solid content concentration (mass%) of binder polymer solution)
(3) Double Bond Equivalent The double bond equivalent is the mass of a polymer per mole of a polymerizable unsaturated bond, and is a calculated value calculated based on the amount of monomer used.
(4) Weight average molecular weight (Mw)
The weight average molecular weight means a weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions and converted into standard polystyrene.
Column: Showdex (registered trademark) LF-804 + LF-804 (manufactured by Showa Denko K.K.)
Column temperature: 40°C
Sample: 0.2% tetrahydrofuran solution of copolymer Developing solvent: tetrahydrofuran Detector: Differential refractometer (Shodex (registered trademark) RI-71S) (manufactured by Showa Denko K.K.)
Flow rate: 1 mL/min
(5) Glass transition temperature (Tg)
The Tg of the binder polymer was measured using a differential scanning calorimeter (DSC7000X, manufactured by Hitachi High-Tech Science Corporation).
Specifically, 1 g of each binder polymer solution was collected and dried at 130° C. for 120 minutes to volatilize the solvent, and 10 mg of each sample was collected from each of the obtained solids. Then, differential scanning calorimetry was performed by changing the temperature of the sample from −0° C. to 200° C. at a heating rate of 10° C./min using a differential scanning calorimeter (DSC), and the endothermic start temperature due to the observed glass transition was taken as the glass transition temperature (Tg). When two Tgs were observed, the average value of the two Tgs was taken as the Tg of the binder polymer.

<Examples 1 to 9 and Comparative Examples 1 to 7>
[Preparation of photosensitive resin composition]
The components (A), (B), (C), (D), (E) and (F) shown in Table 3, Table 4 or Table 5 were blended to obtain the contents (unit: mass %) shown in the same table, and mixed for 15 minutes using a stirrer to prepare a coating liquid for forming a photosensitive resin layer as a photosensitive resin composition.

In Table 3, Table 4 or Table 5, details of the components (A), (B), (C), (D), (E) and (F) are as follows.
(A) Component solutions 1 to 16: Binder polymer solutions 1 to 16 prepared by the above-mentioned methods

Component (B) Photopolymerizable monomer: Trimethylolpropane acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name "A-TMPT")

Component (C) Multifunctional thiol compound: pentaerythritol tetrakis(3-mercaptobutyrate) (KarenzMT (registered trademark) PE1 (number of SH groups = 4), manufactured by Showa Denko K.K.)

(D) A mixed liquid obtained by mixing lactam black (solid content) represented by the following structural formula as a component pigment, a non-amine-based dispersant (solid content) as a dispersant, and PGMEA in a ratio of 15.0:4.5:80.5 (mass ratio) (lactam black organic pigment dispersion (product name "SF BLACK BJ4379", manufactured by Sanyo Pigment Co., Ltd., solid content: 19.5 mass%, lactam black organic pigment: 15 mass%))

Component (E) Photopolymerization initiator: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (product name: "Lunacure TPO", manufactured by DKSH Japan Co., Ltd.)

Component (F) Adhesion aid: Si coupling agent (product name "KBM-803", manufactured by Shin-Etsu Chemical Co., Ltd.)

[Formation of light-shielding pattern]
The photosensitive resin layer forming coating solution obtained as described above was dropped onto a glass plate having a thickness of 3.0 mm, and a coating film was formed by spin coating to obtain a laminate having a coating film on the glass plate. Then, this laminate was placed on a hot plate and heated at 120°C for 2 minutes to remove the solvent, and a first laminate having a photosensitive resin layer was produced. When obtaining the first laminate, the thickness of the coating film was adjusted by adjusting the rotation speed in the spin coating method so that the thickness of the photosensitive resin layer was 15±1 μm.
Next, the first laminate was partially exposed to ultraviolet light using an ultraviolet exposure machine (product name "MA-20", manufactured by Mikasa Co., Ltd.) through a cross-shaped glass mask (manufactured by Shin-ei Co., Ltd.) as a photomask, to obtain a second laminate having a partially cured layer. At this time, the glass mask used had a space width (S) of 40 μm and a line width (L) of 30 μm. The exposure dose was the value (unit: mJ/cm ² ) shown in Table 3, Table 4, or Table 5.
Next, the second laminate was placed on a hot plate and heated (post-baked) at 100° C. for 1 minute as shown in Table 3, Table 4 or Table 5.
Next, the second laminate was placed on an adsorption stage, and spray development was performed using a developing machine (product name "AD-1200", manufactured by Mikasa Co., Ltd.), followed by washing to obtain a third laminate having only the cured portion on the glass plate. In this case, spray development was performed using 2.38% TMAH (tetramethylammonium hydroxide) as the developer at 23°C for the development time shown in Table 3, Table 4 or Table 5. Here, the development time is the minimum time for the uncured portion of the partially cured layer to completely dissolve in the developer. In addition, water washing was performed for 30 seconds using pure water at 23°C.
Thereafter, the entire surface of the third laminate was exposed to ultraviolet light using an ultraviolet light exposure machine (product name "MA-20", manufactured by Mikasa Co., Ltd.) at an exposure dose of 1000 mJ/ ^cm2 .
In this way, a light-shielding pattern was formed on the glass plate.
In this manner, a substrate having a light-shielding pattern with a thickness of 15 μm was formed on the glass plate.
Next, a substrate having a light-shielding pattern was formed in the same manner as above, except that the glass mask used had a line width (L) of 25 μm, 20 μm, 15 μm, 10 μm, 8 μm, 6 μm, or 4 μm.
In this manner, eight types of substrates having a light-shielding pattern were formed.

<Performance evaluation>
The optical density, resolution and reliability of the substrate having the light-shielding pattern were evaluated as follows.
(1) Optical Density (OD value)
The OD value of the light-shielding pattern obtained as described above was calculated based on the relationship between the OD value and the content of the colorant in the total solid content contained in the coating solution for forming a photosensitive resin layer, which was previously obtained, and the content of the colorant in the total solid content contained in the coating solution for forming a photosensitive resin layer. The results are shown in Tables 3, 4, and 5.
The OD value of the light-shielding pattern is indirectly determined as described above because the minimum measurement limit of the transmittance of the transmittance measuring device (product name "Spectral Haze Meter SH 7000", manufactured by Nippon Denshoku Industries Co., Ltd.) to be used to measure the transmittance is 0.03% (equivalent to an OD value of approximately 2.4), and it becomes difficult to calculate the OD value when the OD value is greater than 2.4.
The above relationship was obtained as follows. First, for each Example or Comparative Example, five types of coating liquids for forming a photosensitive resin layer were prepared similarly to each Example or Comparative Example, except that only the content of the colorant in the total solid content was set to 0 mass%, 4 mass%, 6 mass%, 8 mass%, and 10 mass%. Then, each of the five types of coating liquids for forming a photosensitive resin layer was dropped onto a glass plate having a thickness of 3.0 mm, and a coating film was formed by a spin coating method, and a laminate was obtained by forming a coating film on the glass plate. At this time, for each of the five types of coating liquids for forming a photosensitive resin layer, the rotation speed in the spin coating method was adjusted to obtain three laminates having different coating film thicknesses and having a transmittance after solvent removal within the transmittance measurement limit of the transmittance measurement device. Then, each of these three laminates was placed on a hot plate and heated at 120°C for 2 minutes to remove the solvent, and a first laminate was obtained in which a photosensitive resin layer was formed on the glass plate. Next, the first laminate was exposed to ultraviolet light using an ultraviolet light exposure machine (product name "MA-20", manufactured by Mikasa Co., Ltd.) to obtain a cured body. At this time, the exposure dose was 200 mJ/cm ² .
Next, the cured product was placed on a hot plate and heated for 5 minutes at 60° C. In this manner, a sample for transmittance measurement was prepared in which a cured layer having a thickness of 15 μm was formed on a glass plate.
The transmittance of the sample for transmittance measurement was measured using the transmittance measuring device, and the OD value was calculated based on the transmittance and the following formula.
OD value = -log ₁₀ (transmittance at a wavelength of 610 nm/100)
The OD values calculated as above were plotted against the thickness of the cured layer of the transmittance measurement sample, and straight lines passing through the plotted points were formed. At this time, a total of five straight lines were formed for each content of the colorant in the total solid content.
Next, from the five intersections of the straight line where the thickness of the cured layer is 15 μm and the five straight lines obtained as described above, five OD values corresponding to the colorant contents of 0 mass%, 4 mass%, 6 mass%, 8 mass%, and 10 mass% in the total solid content when the thickness of the cured layer is 15 μm were obtained.
These five OD values were then plotted to form a straight line passing through the plotted points. In this way, the above relationship was determined. From the above relationship, it was found that the content of the colorant in the total solid content is proportional to the OD value.
The pass criteria for the OD value were as follows:
(Passing criteria) OD value is 3.0 or more.

(2) Resolution The light-shielding pattern of the substrate with a light-shielding pattern prepared as described above was observed in the thickness direction of the glass plate using a laser microscope (product name "3D MEASURING LASER MICROSCOPE OLS5000", manufactured by OLYMPUS) to measure the line width, and the minimum line width among the line widths satisfying the following conditions was determined. The results are shown in Tables 3, 4, and 5. In Tables 3, 4, and 5, "-" indicates that the photosensitive resin layer-forming coating liquid as the photosensitive resin composition did not have photosensitivity and a light-shielding pattern could not be formed, so that a line width satisfying the following conditions could not be determined.
(conditions)
Thickness: The thickness of the light-shielding pattern must be 90% or more of the thickness of the photosensitive resin layer before exposure. Shape: The cross pattern must be formed without any chipping or distortion. The pass criteria for resolution were as follows:
(Passing criteria) Line width is 15 μm or less

(3) Reliability Among the eight types of substrates with light-shielding patterns prepared as described above, the light-shielding patterns of the substrates with light-shielding patterns prepared using a glass mask having a line width (L) of 15 μmm were left in an environment of 85° C. and 85% RH for 500 hours.
The remaining film rate (%) of the light-shielding pattern in the thickness direction was calculated based on the following formula. The results are shown in Tables 3, 4, and 5. In Tables 3, 4, and 5, "-" indicates that the remaining film rate was not calculated.
Residual film rate (%) = 100 x a1/a0
(In the above formula, a0 represents the initial film thickness (μm) of the light-shielding pattern, and a1 represents the film thickness (μm) of the light-shielding pattern after being left in an environment of 85° C. and 85% RH for 500 hours.)
The reliability criteria were as follows:
(Passing criteria) Remaining film rate is 80% or more

From the results shown in Tables 3, 4 and 5, the photosensitive resin compositions of Examples 1 to 9 met the pass criteria in terms of resolution and reliability even for light-shielding patterns with high OD values. In contrast, the photosensitive resin compositions of Comparative Examples 1 to 7 did not meet the pass criteria in terms of at least one of resolution and reliability for light-shielding patterns with high OD values. In particular, the surfaces of the light-shielding patterns formed using the photosensitive resin compositions of Examples 1 to 9 (surfaces opposite to the surface of the glass plate, which is the substrate) were almost flat. In contrast, the surfaces of the light-shielding patterns formed using the photosensitive resin compositions of Comparative Examples 2 to 5 and 7 were curved in a bowl shape. Note that if the surface of the light-shielding pattern is not curved but is almost flat, advantages such as the smoothness of the display and uniformity of image quality can be easily obtained when there are external factors such as external light reflection or a sealing layer being provided on the upper part of the light-shielding pattern are present.
From the above, it has been confirmed that the photosensitive resin composition of the present disclosure can impart excellent resolution and reliability to a light-shielding pattern having a high optical density.

10...substrate, 20...photosensitive resin layer, 21...light-shielding pattern, 30...partially cured layer, 40...micro LED, 120...substrate with light-shielding pattern, 200...image display device.

Claims (14)

An alkali-soluble binder polymer;
a photopolymerizable monomer having an ethylenically unsaturated group;
A colorant;
A photopolymerization initiator is included,
The alkali-soluble binder polymer contains a structural unit (a) represented by the following formula (1), a structural unit (b) represented by the following formula (2), a structural unit (c) represented by the following formula (3), and a structural unit (d) represented by the following formula (4):
The alkali-soluble binder polymer has a double bond equivalent of 250 to 400 g/mol.

(In the formula (1), ^R1 represents a hydrogen atom or a methyl group, and X represents an alicyclic hydrocarbon group which may have a substituent.)

(In the formula (2), ^R2 represents a hydrogen atom or a methyl group, and Y represents an aromatic group which may have a substituent.)

(In the formula (3), ^R3 represents a hydrogen atom or a methyl group.)

(In the formula (4), ^R4 and ^R5 each independently represent a hydrogen atom or a methyl group.) The photosensitive resin composition according to claim 1, wherein the alkali-soluble binder polymer has a solid content acid value of 25 to 125 mg KOH/g. The photosensitive resin composition according to claim 1, further comprising a polyfunctional thiol compound, the polyfunctional thiol compound having three or more mercapto groups in one molecule. The photosensitive resin composition according to claim 1, wherein the content of the colorant in the total solid content is 15% by mass or less. The photosensitive resin composition according to claim 1, wherein the photopolymerizable monomer has three or more functional groups in one molecule, and the three or more functional groups include the ethylenically unsaturated group and a hydroxyl group. The photosensitive resin composition according to claim 1, wherein the colorant is an organic pigment. The photosensitive resin composition according to claim 1, wherein the photopolymerization initiator comprises an acylphosphine oxide-based photopolymerization initiator. A cured product obtained by curing the photosensitive resin composition according to any one of claims 1 to 7. A photosensitive resin layer forming step of forming a photosensitive resin layer on a substrate using the photosensitive resin composition according to any one of claims 1 to 7;
an exposure step of exposing the photosensitive resin layer provided on the base material to light to form a partially cured layer;
a heating step of heating the partially cured layer;
and a developing step of forming a light-shielding pattern by performing alkali development on the partially cured layer. The method for manufacturing a substrate with a light-shielding pattern according to claim 9, wherein the height of the photosensitive resin layer from the substrate is 5.0 μm or more. A substrate with a light-shielding pattern obtained by the method for producing a substrate with a light-shielding pattern according to claim 9. An image display device comprising the light-shielding patterned substrate according to claim 11. A process for forming a substrate having a light-shielding pattern by the method for producing a substrate having a light-shielding pattern according to claim 9;
a micro LED mounting step of mounting a micro LED on the substrate;
A manufacturing method of an image display device comprising the steps of: a micro LED forming step of forming a micro LED on the substrate;
A process for forming a substrate having a light-shielding pattern by the method for producing a substrate having a light-shielding pattern according to claim 9;
A manufacturing method of an image display device comprising the steps of:

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