JP2023127627A - Substrate for display devices and image display device - Google Patents

Abstract

To provide a substrate for display devices and an image display device which have high transparency and are superior in heat resistance and yellowing resistance.SOLUTION: A substrate 10 for display devices includes: a substrate 1 on which two or more light-emitting elements 2 for emitting near ultraviolet light or light in a blue wavelength band are arranged; partition walls 4 surrounding each of the light-emitting elements 2; and a resin layer 3 positioned on the surfaces of the light-emitting elements 2. The resin layer 3 is a cured product of a resin composition containing a silicone resin (A). The silicone resin (A) contains 40-80 mol% of a repeating unit represented by a specific structure based on the total number of repeating units constituting the silicone resin (A).SELECTED DRAWING: Figure 1

Description

The present invention relates to a display device substrate and an image display device.

In recent years, light emitting diodes (LEDs) have rapidly become popular. LEDs are used in displays and lighting for televisions, computers, tablets, smartphones, etc. An image display device using LEDs can perform display without using a liquid crystal that switches between light transmission and non-transmission. For this reason, image display devices using LEDs are particularly superior in visibility in dark places, compared to liquid crystal display devices that suffer from light leakage when displaying black.

A micro LED is an image display device that has a structure in which LED chips of approximately 2 μm to 50 μm in size are arranged in a matrix, and displays by individually driving each of a plurality of LEDs. Such micro LEDs can perform display without using liquid crystal.

Micro LEDs are broadly divided into two types: one that uses three types of LED elements that emit red, green, and blue light, and the other that uses only monochromatic LED elements such as LED chips that emit light in the wavelength range from blue to near ultraviolet. Separated. In micro-LEDs, individual LED elements play the role of a display functional layer. The method using three types of LED elements, which emit red light, green light, and blue light, has the advantage of excellent brightness and long life, but has the drawback that it requires many processes to mount LED elements with different light emission colors, which increases cost. The disadvantage is that the driving voltages are different and it is difficult to control them.

In a method using monochromatic LED elements, each of a plurality of monochromatic LED elements is provided with a wavelength conversion layer (for example, quantum dots, inorganic phosphors, etc.) that converts the emission wavelength to red, green, or blue. Color display is achieved by layering dispersions).

For example, Patent Document 1 discloses that the excitation light is ultraviolet light (for example, a monochromatic light source in the violet or ultraviolet region), and a color conversion layer (resin layer) that converts the excitation light into red, green, or blue light is provided. An image display device including the following has been proposed.

Resin layers used in image display devices are required to have heat resistance and yellowing resistance in order to maintain high transparency.
To address these problems, for example, Patent Document 2 proposes a photocrosslinkable resin composition containing an acrylic resin having an alicyclic epoxy group and a photocationic polymerization agent as essential components. According to the invention of Patent Document 2, weather resistance, yellowing resistance, etc. are improved.
Patent Document 3 proposes a semiconductor chip using a silicone resin having a dimethylsiloxane skeleton as a sealing material. According to the invention of Patent Document 3, it is attempted to improve the transparency of the sealing material.

International Publication No. 2019-159702 Japanese Patent Application Publication No. 2-289611 JP2003-273292A

However, the resins used in Patent Documents 2 and 3 deteriorate due to ultraviolet light and heat from the light emitting elements, cannot maintain high transparency, and have insufficient heat resistance and yellowing resistance.

Therefore, an object of the present invention is to provide a substrate for a display device and an image display device that have high transparency and are excellent in heat resistance and yellowing resistance.

As a result of intensive studies, the present inventors have found that the above problem can be solved by using a silicone resin containing a specific amount of silsesquioxane structural units in the resin layer.
That is, the present invention has the following aspects.

［式（ｉａ）中、Ｒは、水素原子又は炭素数１～３０かつ１価～３価の炭化水素基であり、前記炭化水素基は、脂肪族でも芳香族でもよく、飽和でも不飽和でもよく、直鎖状でも分岐状でも環状でもよく、前記炭化水素基の炭素数が２以上の場合、前記炭化水素基における１つ以上のメチレン基が非置換、又は酸素、イミド基もしくはカルボニル基で置換されており、前記炭化水素基における１つ以上の水素が非置換、又はフッ素、水酸基もしくは炭素数１～２０のアルコキシ基で置換されており、かつ、１つ以上の炭素が非置換、又はケイ素で置換されており、前記炭化水素基が２価又は３価の場合、前記炭化水素基は、複数の繰り返し単位に含まれるＳｉ同士を連結する。］
［２］前記樹脂層の一部又は全部が蛍光体をさらに含む蛍光体層である、［１］に記載の表示装置用基板。
［３］前記蛍光体が、発光中心にユウロピウムを有する、［２］に記載の表示装置用基板。
［４］前記蛍光体が、波長３８０～４８０ｎｍの青色光源によって励起可能あり、蛍光スペクトルのピーク波長が４００～７００ｎｍの範囲内にある、［２］又は［３］に記載の表示装置用基板。
［５］前記蛍光体の含有量が、前記蛍光体層の総質量に対して、２０～７０質量％である、［２］～［４］のいずれかに記載の表示装置用基板。
［６］前記蛍光体層が、量子ドットをさらに含む、［２］～［５］のいずれかに記載の表示装置用基板。
［７］前記樹脂層の厚さが１～５０μｍである、［１］～［６］のいずれかに記載の表示装置用基板。 [1] A substrate on which two or more light emitting elements that emit light in the near ultraviolet or blue wavelength band are arranged;
a partition wall surrounding each of the light emitting elements;
A display device substrate comprising a resin layer located on a surface of the light emitting element,
The resin layer is a cured product of a resin composition containing a silicone resin (A),
The silicone resin (A) contains 40 to 80 mol% of repeating units represented by the following formula (ia) based on the total number of repeating units constituting the silicone resin (A), a substrate for a display device. .

[In formula (ia), R is a hydrogen atom or a monovalent to trivalent hydrocarbon group having 1 to 30 carbon atoms, and the hydrocarbon group may be aliphatic or aromatic, and may be saturated or unsaturated. Often, the hydrocarbon group may be linear, branched, or cyclic, and when the number of carbon atoms in the hydrocarbon group is 2 or more, one or more methylene groups in the hydrocarbon group are unsubstituted or oxygen, imide group, or carbonyl group. one or more hydrogens in the hydrocarbon group are unsubstituted, or substituted with fluorine, a hydroxyl group, or an alkoxy group having 1 to 20 carbon atoms, and one or more carbons are unsubstituted, or When the hydrocarbon group is substituted with silicon and is divalent or trivalent, the hydrocarbon group connects Si contained in a plurality of repeating units. ]
[2] The display device substrate according to [1], wherein part or all of the resin layer is a phosphor layer further containing a phosphor.
[3] The display device substrate according to [2], wherein the phosphor has europium at its emission center.
[4] The substrate for a display device according to [2] or [3], wherein the phosphor can be excited by a blue light source with a wavelength of 380 to 480 nm and has a peak wavelength of a fluorescence spectrum in the range of 400 to 700 nm.
[5] The display device substrate according to any one of [2] to [4], wherein the content of the phosphor is 20 to 70% by mass based on the total mass of the phosphor layer.
[6] The display device substrate according to any one of [2] to [5], wherein the phosphor layer further includes quantum dots.
[7] The display device substrate according to any one of [1] to [6], wherein the resin layer has a thickness of 1 to 50 μm.

[8] An image display device comprising the display device substrate according to any one of [1] to [7].

According to the display device substrate and image display device of the present invention, it has high transparency and is excellent in heat resistance and yellowing resistance.

FIG. 1 is a cross-sectional view of a display device substrate according to an embodiment of the present invention. 1 is a sectional view of an image display device according to an embodiment of the present invention. 1 is a graph of transmission spectra of Example 1 and Comparative Example 1. 2 is a graph of transmission spectra of Example 2, Comparative Example 2, Example 4, and Comparative Example 4. It is a graph of the excitation spectrum and fluorescence spectrum of a phosphor that emits green light. It is a graph of the excitation spectrum and fluorescence spectrum of a phosphor that emits red light.

Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same or substantially the same functions and components are given the same reference numerals, and the description thereof will be omitted or simplified, or will be described only when necessary. In each figure, in order to make each component large enough to be recognized on the drawing, the dimensions and proportions of each component are appropriately different from those in reality. In addition, if necessary, elements that are difficult to illustrate, such as the structure of thin film transistors, the structure of multiple layers that make up the conductive layer, wiring connections to circuit parts, switching elements (transistors), etc. Illustration is omitted.

[Substrate for display device]
Hereinafter, a display device substrate according to an embodiment of the present invention will be described in detail based on FIG. 1.
As shown in FIG. 1, the display device substrate 10 includes a substrate 1, a light emitting element 2, a resin layer 3, and a partition wall 4. The light emitting element 2 is arranged on the substrate 1 and surrounded by a partition wall 4. The resin layer 3 is located on the surface of the light emitting element 2 and is formed in a region S surrounded by the partition walls 4.
In this embodiment, each region S is divided by one partition wall 4 provided between adjacent light emitting elements 2 .
In this specification, the "display device substrate" may be only one display device substrate 10 (also referred to as a unit pixel), or two or more unit pixels are arranged horizontally to form a matrix. It may be something that you do.

≪Substrate≫
Examples of the substrate 1 include a glass plate, a resin plate, and a resin film.
Examples of the material for the glass plate include soda lime glass and non-alkali glass, with non-alkali glass being preferred.
Examples of the material for the resin plate and resin film include polyester, (meth)acrylic polymer, polyimide, polyether sulfone, and the like. Here, "(meth)acrylic polymer" is a general term for both acrylic polymer and methacrylic polymer.
The thickness T ₁ of the substrate 1 is preferably 1 mm or less, more preferably 0.8 mm or less, and even more preferably 0.1 mm or less. When the thickness T ₁ of the substrate 1 is less than or equal to the above upper limit value, the display device substrate 10 can be made more lightweight. Although the lower limit of the thickness _T1 of the substrate 1 is not particularly limited, it is, for example, 0.01 mm.

≪Light-emitting element≫
As the light emitting element 2, a plurality of light emitting diode elements called LEDs (Light Emitting Diodes) can be used. An LED element and a light emitting diode element refer to an LED, and may be simply referred to as an LED in the following description.

Examples of LEDs include aluminum gallium arsenide (AlGaAs), gallium arsenide phosphide (GaAsP), indium gallium nitride (InGaN)/gallium nitride (GaN)/aluminum gallium nitride (AlGaN), gallium phosphide (GaP), and zinc selenide. Compounds such as (ZnSe) and aluminum indium gallium phosphide (AlGaInP) are used.
The light emitting element 2 of this embodiment emits light in the near ultraviolet or blue wavelength band. The light emitting element 2 is a monochromatic LED, and is mainly made of gallium nitride (GaN).

In this specification, blue refers to light having a wavelength of 410 nm or more and less than 490 nm. A blue LED (LED that emits blue light) is an LED that has an emission peak within a wavelength range of 410 nm or more and less than 490 nm. In an embodiment of the present invention, near-ultraviolet light refers to light having a wavelength of 300 nm or more and less than 410 nm (emission from violet to near-ultraviolet). A near-ultraviolet LED is an LED that has an emission peak within a wavelength range of 300 nm or more and less than 410 nm.
In this specification, a monochromatic light-emitting LED refers to an LED having a half-value width of 70 nm or less and having one emission peak within the above wavelength range. The smaller the half width is, the more preferable it is.

In a micro LED display, for example, an LED element (LED chip) having a size of 2 μm to 50 μm can be used. Regarding the structure of the LED element, a horizontal LED in which the n-side electrode and the p-side electrode are on the same side may be used, but the n-side electrode and the p-side electrode are on different surfaces (opposite parallel surfaces) in the thickness direction of the LED. Vertical LEDs can also be used. In the following description, the upper electrode and the lower electrode refer to either the n-side electrode or the p-side electrode of the vertical LED.

≪Resin layer≫
The resin layer 3 is a cured product of a resin composition containing silicone resin (A).
The resin composition forming the resin layer 3 contains silicone resin (A).
In the resin composition, the silicone resin (A) is preferably a base material.
In this specification, the base material refers to the resin with the highest content among the resins contained in the resin composition.
The content of silicone resin (A) in the resin composition is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, and even more preferably 40 to 60% by mass, based on the total mass of the resin composition. When the content of the silicone resin (A) is at least the above lower limit, the heat resistance and yellowing resistance of the resin layer 3 can be further improved. When the content of the silicone resin (A) is at most the above upper limit, the transparency of the resin layer 3 can be further improved.

A silicone resin is a resin whose main chain is a siloxane bond (Si--O--Si bond).
The silicone resin (A) of this embodiment contains a repeating unit represented by the following formula (ia).

In formula (ia), R is a hydrogen atom or a monovalent to trivalent hydrocarbon group having 1 to 30 carbon atoms. The hydrocarbon group may be aliphatic or aromatic, saturated or unsaturated, and linear, branched, or cyclic. When the hydrocarbon group has two or more carbon atoms, one or more methylene groups in the hydrocarbon group may be unsubstituted or substituted with oxygen, an imide group, or a carbonyl group. When the hydrocarbon group has 2 or more carbon atoms, one or more hydrogen atoms in the hydrocarbon group may be unsubstituted or substituted with fluorine, a hydroxyl group, or an alkoxy group having 1 to 20 carbon atoms. When the hydrocarbon group has two or more carbon atoms, one or more carbons in the hydrocarbon group may be unsubstituted or substituted with silicon. When the hydrocarbon group is divalent or trivalent, the hydrocarbon group may connect Si contained in a plurality of repeating units.

In formula (ia), R is preferably a hydrocarbon group.
When R is a hydrocarbon group, the number of carbon atoms in the hydrocarbon group is preferably 1 to 10, more preferably 1 to 6. The valence of the hydrocarbon group is preferably divalent or trivalent, more preferably trivalent. The hydrocarbon group is preferably aliphatic. The hydrocarbon group is preferably saturated. The hydrocarbon group is preferably branched.

When hydrogen in the hydrocarbon group is substituted with an alkoxy group, the number of carbon atoms in the alkoxy group is preferably 1 to 20, more preferably 1 to 6.

The repeating unit represented by formula (ia) is a silsesquioxane structural unit.
Silsesquioxane is a network polymer or polyhedral cluster having a structure of (RSiO _1.5 ) _n (n is a natural number) obtained by hydrolyzing trifunctional silane. Each silicon atom is bonded to an average of 1.5 oxygen atoms and one hydrocarbon group. It is an inorganic compound that has a cage-like skeleton made up of up to eight organic functional groups and Si--O bonds. Silsesquioxane is a stoichiometric compound between silica (SiO ₂ ) and silicone (R ₂ SiO), and is an inorganic substance that has an affinity for organic substances.
The silicone resin (A) has excellent heat resistance and yellowing resistance because it has a silsesquioxane structural unit.

The content of the silsesquioxane structural unit is 40 to 80 mol%, preferably 45 to 75 mol%, and more preferably 50 to 70 mol%, based on the total number of repeating units constituting the silicone resin (A). preferable. When the content of the silsesquioxane structural unit is at least the above lower limit, the heat resistance and yellowing resistance of the resin layer 3 can be further improved. When the content of the silsesquioxane structural unit is below the above upper limit, when the resin layer 3 contains a phosphor described later, the heat resistance and resistance of the resin layer 3 are improved without inhibiting the light emission of the phosphor. Yellowing can be further enhanced.
The content of silsesquioxane structural units can be determined, for example, by gas chromatography (GC), liquid chromatography (LC), or the like.

The silicone resin (A) may contain a repeating unit represented by the following formula (ib).

The content of the repeating unit represented by formula (ib) is preferably 40 mol% or less, more preferably 10 to 20 mol%, based on the total number of repeating units constituting the silicone resin (A). When the content of the repeating unit represented by formula (ib) is at least the above lower limit, the heat resistance and yellowing resistance of the resin layer 3 can be further improved. When the content of the repeating unit represented by formula (ib) is below the above upper limit, the transparency of the resin layer 3 can be further improved.
The content of the repeating unit represented by formula (ib) can be determined by, for example, gas chromatography, liquid chromatography, or the like.

The silicone resin (A) may contain repeating units other than the repeating unit represented by formula (ia) and the repeating unit represented by formula (ib) (hereinafter also referred to as "other repeating units"). good. Examples of other repeating units include repeating units derived from vinyl compounds, repeating units derived from acrylic compounds, repeating units derived from polyester compounds, and the like. The content of other repeating units is preferably 1 mol% or less, more preferably 0 mol%, based on the total number of repeating units constituting the silicone resin (A). When the content of other repeating units is below the above upper limit, the organic substance content of the resin layer 3 can be reduced, and the heat resistance and yellowing resistance of the resin layer 3 can be further improved.
The content of other repeating units can be determined by, for example, gas chromatography, liquid chromatography, or the like.

The mass average molecular weight of the silicone resin (A) is preferably 500 to 25,000, more preferably 1,000 to 20,000. When the mass average molecular weight of the silicone resin (A) is at least the above lower limit, the heat resistance and yellowing resistance of the resin layer 3 can be further improved. When the mass average molecular weight of the silicone resin (A) is at most the above upper limit, the transparency of the resin layer 3 can be further improved.
In this specification, the mass average molecular weight means the mass average molecular weight in terms of polystyrene, and is determined by gel permeation chromatography (GPC) using polystyrene as a reference material.

Examples of the monomer of the silicone resin (A) include Pentacyclo[9.5.1.13, 9.15, 15.17, 13]octasiloxane, 1,3,5,7,9,11,13-heptamethyl- 15-phenyl- (CAS No. 18616-10-9), Pentacyclo[9.5.1.13, 9.15, 15.17, 13] octasiloxane, 1,3,5,7,9,13-hexamethyl Completely caged silsesquioxanes such as -11,15-diphenyl- (CAS No. 18421-62-0) can be mentioned.

The resin composition forming the resin layer 3 may contain components other than the silicone resin (A). Examples of components other than the silicone resin (A) include a photopolymerization initiator (B), a photopolymerizable compound (C), and an organic solvent (D).

The photopolymerization initiator (B) generates radicals when irradiated with ultraviolet light.
Examples of the photopolymerization initiator (B) include benzoins (benzoin, benzoin alkyl ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, etc.), phenyl ketones [e.g., acetophenones (e.g., acetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, etc.), 2- Alkylphenyl ketones such as hydroxy-2-methylpropiophenone; cycloalkylphenyl ketones such as 1-hydroxycyclohexylphenyl ketone], aminoacetophenones {2-methyl-1-[4-(methylthio)phenyl]- 2-morpholinoaminopropanone-1, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, etc.}, anthraquinones (anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2- t-butylanthraquinone, 1-chloroanthraquinone, etc.), thioxanthones (2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone, etc.), ketals (acetophenone dimethyl ketal, benzyl dimethyl ketal, etc.), benzophenones (benzophenone, etc.), xanthones, phosphine oxides (eg, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, etc.), and the like. These photopolymerization initiators (B) may be used alone or in combination of two or more.

The content of the photopolymerization initiator (B) is preferably 0.01 to 20% by mass, more preferably 0.1 to 5% by mass, based on the total mass of the resin composition forming the resin layer 3. When the content of the photopolymerization initiator (B) is at least the above lower limit, the resin composition forming the resin layer 3 can be sufficiently cured. When the content of the photopolymerization initiator (B) is below the above upper limit, unreacted photopolymerization initiator (B) is less likely to remain, and the transparency of the resin layer 3 can be further improved.

The photopolymerizable compound (C) is a resin that polymerizes and hardens when irradiated with active energy rays such as ultraviolet rays. As the photopolymerizable compound (C), for example, a monofunctional, bifunctional, or trifunctional or more functional (meth)acrylate monomer can be used.
In this specification, "(meth)acrylate" is a generic term for both acrylate and methacrylate, and "(meth)acryloyl" is a generic term for both acryloyl and methacryloyl.

Examples of monofunctional (meth)acrylate compounds include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate. meth)acrylate, t-butyl(meth)acrylate, glycidyl(meth)acrylate, acryloylmorpholine, N-vinylpyrrolidone, tetrahydrofurfuryl acrylate, cyclohexyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, isobornyl(meth)acrylate, ) acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, benzyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3- Methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phosphoric acid (meth)acrylate, ethylene oxide modified phosphoric acid (meth)acrylate, phenoxy (meth)acrylate, ethylene oxide modified phenoxy (meth)acrylate, propylene oxide modified Phenoxy (meth)acrylate, nonylphenol (meth)acrylate, ethylene oxide-modified nonylphenol (meth)acrylate, propylene oxide-modified nonylphenol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypropylene glycol (meth)acrylate ) acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl hydrogen phthalate, 2-(meth)acryloyloxypropyl Hydrogen phthalate, 2-(meth)acryloyloxypropyl hexahydrohydrogen phthalate, 2-(meth)acryloyloxypropyl tetrahydrohydrogen phthalate, dimethylaminoethyl (meth)acrylate, trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth)acrylate, octafluoropropyl (meth)acrylate, 2-adamantane, adamantane derivative mono(meth)acrylate such as adamantyl acrylate having a monovalent mono(meth)acrylate derived from adamantane diol, etc. can be mentioned.

Examples of difunctional (meth)acrylate compounds include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, and nonanediol di(meth)acrylate. acrylate, ethoxylated hexanediol di(meth)acrylate, propoxylated hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, Di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethoxylated neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, etc. Examples include acrylate.

Examples of tri- or higher functional (meth)acrylate compounds include trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, and tris-2-hydroxyethyl. Tri(meth)acrylates such as isocyanurate tri(meth)acrylate, glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, etc. Functional (meth)acrylate compounds, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane penta(meth)acrylate, ) acrylate, dipentaerythritol hexa(meth)acrylate, ditrimethylolpropane hexa(meth)acrylate, and other trifunctional or higher functional polyfunctional (meth)acrylate compounds, and some of these (meth)acrylates can be converted into alkyl groups or ε-caprolactone. Examples include polyfunctional (meth)acrylate compounds substituted with .

Moreover, urethane (meth)acrylate can also be used as the photopolymerizable compound (C). Examples of urethane (meth)acrylate include those obtained by reacting a (meth)acrylate monomer having a hydroxyl group with a product obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer. .

Examples of urethane (meth)acrylates include pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate toluene diisocyanate Examples include urethane prepolymer, pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate isophorone diisocyanate urethane prepolymer.

The above-mentioned (meth)acrylate compounds may be used alone or in combination of two or more. Furthermore, the above-mentioned (meth)acrylate compound may be a monomer in the composition for forming a colored layer, or may be a partially polymerized oligomer.

The content of the photopolymerizable compound (C) is preferably 0.01 to 20% by mass, more preferably 1 to 10% by mass, based on the total mass of the resin composition forming the resin layer 3. When the content of the photopolymerizable compound (C) is at least the above lower limit, the transparency of the resin layer 3 can be further improved. When the content of the photopolymerizable compound (C) is below the above upper limit, the handleability of the resin composition forming the resin layer 3 can be further improved.

In the resin composition of the present embodiment, the mass ratio (hereinafter also referred to as "A/C ratio") represented by (content of silicone resin (A))/(content of photopolymerizable compound (C)). ) is, for example, preferably 1 to 8,000, more preferably 1 to 1,000, even more preferably 5 to 500, particularly preferably 10 to 100. When the A/C ratio is at least the above lower limit, the heat resistance and yellowing resistance of the resin layer 3 can be further improved. When the A/C ratio is below the above upper limit, the transparency of the resin layer 3 can be further improved.

Examples of the organic solvent (D) include ethers, ketones, esters, cellosolves, and the like. Examples of the ethers include dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran, anisole, and phenetol. Can be mentioned. Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, and ethylcyclohexanone. Examples of the esters include ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, n-pentyl acetate, and γ-butyrolactone. Examples of cellosolves include methyl cellosolve, cellosolve (ethyl cellosolve), butyl cellosolve, and cellosolve acetate. The organic solvent (D) may be used alone or in combination of two or more.

The content of the organic solvent (D) is preferably 20 to 80% by mass, more preferably 40 to 60% by mass, based on the total mass of the resin composition forming the resin layer 3. When the content of the organic solvent (D) is within the above numerical range, the dispersibility of the phosphor described later becomes good, and the light emitting characteristics of the display device substrate 10 can be further improved.

The resin composition of this embodiment may contain components other than the above-mentioned (A) to (D). Examples of other components include additives such as phosphors and ultraviolet absorbers, which will be described later.
When the resin composition contains other components, the content of the other components is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass, based on the total mass of the resin composition. .

The resin layer 3 is obtained by curing the resin composition of this embodiment.
The thickness T ₃ of the resin layer 3 is preferably 1 to 50 μm, more preferably 2 to 40 μm, and even more preferably 3 to 30 μm. When the thickness T ₃ of the resin layer 3 is equal to or greater than the above lower limit, the light emitting characteristics of the display device substrate 10 can be further improved. When the thickness T ₃ of the resin layer 3 is less than or equal to the above upper limit value, the production efficiency of the display device substrate 10 can be further improved.
The thickness T ₃ of the resin layer 3 is determined, for example, by observing a cross section of the display device substrate 10 in the thickness direction using a microscope or the like.
The thickness T3 of the resin layer ₃ can be adjusted depending on the amount of the resin composition used and the height _H4 of the partition wall 4, which will be described later.

The transmittance of the resin layer 3 at 385 nm is preferably 96.0% or more, more preferably 97.0% or more, and even more preferably 98.0% or more. When the transmittance of the resin layer 3 at 385 nm is equal to or higher than the above lower limit, the transparency of the resin layer 3 can be further improved. The upper limit of the transmittance of the resin layer 3 at 385 nm is preferably as high as possible, and ideally it is 100%.
The transmittance of the resin layer 3 at 385 nm can be measured using, for example, an ultraviolet-visible spectrophotometer.
Note that the transmittance of the resin layer 3 at 385 nm is determined immediately after manufacturing the display device substrate 10, more specifically, after manufacturing, under an environment of room temperature (for example, 5 to 30° C.) and humidity of 20 to 70% RH. It means the transmittance measured within 24 hours after storage for 24 hours (hereinafter also referred to as "initial transmittance").
The initial transmittance of the resin layer 3 can be adjusted by, for example, the type and amount of the silicone resin (A), the type and amount of the photopolymerizable compound (C), and a combination thereof contained in the resin composition.

The transmittance at 385 nm after heating the resin layer 3 in air at 150° C. for 500 hours (hereinafter also referred to as "transmittance after heating") is preferably 95.0% or more, and 95.5 % or more, more preferably 96.0% or more. When the transmittance after heating is equal to or higher than the above lower limit, the resin layer 3 has better heat resistance and yellowing resistance. The higher the upper limit value of the transmittance after heating, the more preferable it is, and ideally it is 100%.
The transmittance after heating can be measured, for example, by placing the display device substrate 10 in an oven set at 150° C., taking it out of the oven after 500 hours, and using an ultraviolet-visible spectrophotometer.
The transmittance after heating can be adjusted by, for example, the type and amount of the silicone resin (A), the amount of the repeating unit represented by the formula (ia) that the silicone resin (A) has, and the like.

The difference between the initial transmittance and the transmittance after heating of the resin layer 3 (hereinafter also referred to as "transmittance difference") is preferably 2.0% or less, more preferably 1.0% or less, and 0.0% or less. More preferably, it is 5% or less. When the transmittance difference is below the above upper limit value, the resin layer 3 has better heat resistance and yellowing resistance. The lower limit of the transmittance difference is preferably as small as possible, and ideally it is 0.0%.
The transmittance difference is determined by the following formula (I).
Transmittance difference (%) = Initial transmittance (%) - Transmittance after heating (%)... (I)

The transmittance retention rate of the resin layer 3 expressed by the following formula (II) (hereinafter also referred to as "transmittance retention rate") is preferably 90% or more, more preferably 95% or more, and 98% or more. is even more preferable. When the transmittance retention rate is equal to or higher than the above lower limit value, the resin layer 3 can maintain high transparency and has excellent heat resistance and yellowing resistance. The higher the upper limit value of the transmittance retention rate, the more preferable it is, and ideally it is 100%.
Transmittance retention rate (%) = {(Transmittance after heating (%))/(Initial transmittance (%))}×100...(II)

The content of the silicone resin (A) in the resin layer 3 is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, and even more preferably 40 to 60% by mass, based on the total mass of the resin layer 3. When the content of the silicone resin (A) in the resin layer 3 is at least the above lower limit, the heat resistance and yellowing resistance of the resin layer 3 can be further improved. When the content of silicone resin (A) in the resin layer 3 is below the above upper limit, the transparency of the resin layer 3 can be further improved.

A part or all of the two or more resin layers 3 may be a phosphor layer containing a phosphor. When the resin layer 3 is a phosphor layer, the phosphor is excited by the light emitted from the light emitting element 2 and emits green or red fluorescence. Therefore, the display device substrate 10 functions as a pixel that emits the three primary colors. When the resin layer 3 is a phosphor layer, the wavelength of the light emitted from the light emitting element 2 is converted and the color is converted. That is, when the resin layer 3 is a phosphor layer, the display device substrate 10 functions as a color conversion substrate.

Examples of the phosphor include Eu ²⁺ -activated phosphor having europium (Eu ²⁺ ) in its emission center, Mn ²⁺ -activated phosphor having manganese (Mn ²⁺ ) in its emission center, and the like.
When the phosphor is irradiated with excitation light, the emitting ions (eg, Eu ²⁺ ) absorb the excitation light, and the electrons at the ground level are excited to the excitation level. When this excited electron returns to the ground level again, the difference in energy is emitted as fluorescence. Eu ²⁺ , which is a light-emitting ion, has a high transition probability because the emission and absorption transitions are permissible transitions. On the other hand, Mn ²⁺ , which is a luminescent ion, has a forbidden transition between emission and absorption. Therefore, although the transition probability is low, light emission having a narrow spectral width can be obtained, and color reproducibility can be improved.

Examples of the Eu ²⁺ activated phosphor include CASN phosphor.
An example of the Mn ²⁺ activated phosphor is a KSF phosphor.
The CASN phosphor has a wider peak wavelength wavelength width than the KSF phosphor. However, the time required for the emission intensity of the secondary light from the CASN phosphor to reach 1/e (e is the base of the natural logarithm) when the primary light from the LED element is turned off (hereinafter referred to as "afterglow time") ) is approximately 1 to 10 μs.
The KSF phosphor has an afterglow time of about 10 ms, which is about 100 to 1000 times longer than the afterglow time of the CASN phosphor. Therefore, when turning on or off an LED in an image display device, even when the light from the LED element is off, red light remains from the KSF phosphor that is excited and emitted by the light from the LED element. Light exists. Due to the afterglow of the red light from the KSF phosphor, problems such as a phenomenon in which displayed images appear colored or a so-called crosstalk phenomenon in which left and right images appear mixed during 3D display occur. This crosstalk phenomenon occurs conspicuously, for example, in a video in which subtitle characters flow on the screen, and a portion of the subtitle appears red. For this reason, Eu ²⁺ activated phosphor is preferable as the phosphor.
When only Eu ²⁺ activated phosphor with a short afterglow time is used as the phosphor, the performance as an image display device can be improved. Note that the Eu ²⁺ activated phosphor has a wide peak wavelength wavelength range and is inferior in color reproducibility compared to the Mn ²⁺ activated phosphor. However, by providing a color filter layer on the phosphor layer, color reproducibility can be covered.

The dispersed particle size of the phosphor is preferably 0.5 to 30 μm, more preferably 1 to 20 μm. When the dispersed particle size of the phosphor is equal to or larger than the above lower limit, the heat resistance of the phosphor layer can be further improved. When the dispersed particle size of the phosphor is less than or equal to the above upper limit, the color reproducibility of the phosphor layer can be further improved.
In this specification, the dispersed particle size of the phosphor refers to the average particle size after dispersing the phosphor in a resin composition, and the particle size at 50% of the integrated value in the particle size distribution determined by the photon correlation method. means.

The content of the phosphor is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and even more preferably 30 to 50% by mass, based on the total mass of the phosphor layer. When the content of the phosphor is equal to or higher than the above lower limit, the emission intensity of the phosphor layer can be further increased. When the content of the phosphor is below the above upper limit, the transmittance of the phosphor layer can be further increased.

The phosphor layer may further include quantum dots. Quantum dots refer to nanometer-sized semiconductor fine particles that have a quantum confinement effect. When the phosphor layer contains quantum dots, the color reproducibility of the phosphor layer can be further improved.
The content of quantum dots is preferably 10 to 70% by mass, more preferably 20 to 50% by mass, based on the total mass of the phosphor layer. When the quantum dot content is at least the above lower limit, the color reproducibility of the phosphor layer can be further improved. When the content of quantum dots is below the above upper limit, the heat resistance of the phosphor layer can be further improved.

≪Bulkhead≫
The partition walls 4 partition the plurality of resin layers 3 in the plane direction of the substrate 1 . The display device substrate 10 has the function of preventing color mixing of light between adjacent resin layers 3 by providing the partition walls 4 . The shape of the partition wall 4 in plan view is not particularly limited, and examples thereof include a square shape, a rectangular shape, a rhombus shape, a parallelogram shape, a triangular shape, and the like.
Examples of the partition wall 4 include those in which the surface of a wall formed of photoresist is coated with a metal thin film of a highly reflective metal, such as aluminum or silver. The partition wall 4 preferably has light reflective properties, and may have light scattering properties.

The height H ₄ of the partition wall 4 is preferably 1 to 50 μm, more preferably 2 to 40 μm, and even more preferably 3 to 30 μm. When the height H ₄ of the partition wall 4 is equal to or greater than the above lower limit value, the light emitting characteristics of the display device substrate 10 can be further improved. When the height H ₄ of the partition wall 4 is less than or equal to the above upper limit value, light emitted from the light emitting element 2 can be extracted more efficiently.
Here, the height H ₄ of the partition wall 4 refers to the length of the partition wall 4 in the direction perpendicular to the surface of the substrate 1 . The height H ₄ of the partition wall 4 is determined, for example, by observing a cross section of the display device substrate 10 in the thickness direction using a microscope or the like.
The height H ₄ of the partition wall 4 can be adjusted depending on the shape of the pattern when forming the partition wall 4 .

The thickness T ₄ of the partition wall 4 is preferably 0.5 to 30 μm, more preferably 1 to 25 μm, and even more preferably 2 to 20 μm. When the thickness T ₄ of the partition wall 4 is equal to or greater than the above lower limit value, color mixing of light between adjacent resin layers 3 can be more reliably prevented. When the thickness T ₄ of the partition wall 4 is less than or equal to the above upper limit value, the light emitting area of the resin layer 3 can be made larger.
Here, the thickness T ₄ of the partition wall 4 refers to the length of the partition wall 4 in the horizontal direction with respect to the surface of the substrate 1 . The thickness T ₄ of the partition wall 4 is determined, for example, by observing a cross section of the display device substrate 10 in the thickness direction using a microscope or the like.
The thickness T ₄ of the partition wall 4 can be adjusted depending on the shape of the pattern when forming the partition wall 4 .

The reflectance per 10 μm thickness of the partition wall 4 (hereinafter also referred to as "reflectance of the partition wall 4") is preferably 60 to 90%, more preferably 65 to 85%, and even more preferably 70 to 80%. When the reflectance of the partition wall 4 is equal to or higher than the above lower limit value, the brightness of the resin layer 3 can be further increased by utilizing the reflection of light on the side surface of the partition wall 4. When the reflectance of the partition wall 4 is less than or equal to the above upper limit value, scattering of light can be suppressed and the light emitting characteristics of the display device substrate 10 can be further improved.
In this specification, the reflectance of the partition wall 4 is measured using a spectrophotometer (Co., Ltd. ) Refers to the reflectance measured using SolidSpec-3700iDUV (manufactured by Shimadzu Corporation).
The reflectance of the partition wall 4 can be adjusted by changing the type and thickness of the thin film on the surface of the partition wall 4.

[Method for manufacturing display device substrate]
The method for manufacturing the display device substrate 10 of this embodiment is not particularly limited as long as the above-described structure can be formed.
For example, a partition composition for forming the partition walls 4 is applied to the surface of the substrate 1, and a pattern is formed to obtain a substrate with partition walls. A light emitting element 2 is formed or arranged on the surface of the substrate 1 in each region S surrounded by the partition walls 4 of the obtained partition wall-equipped substrate.
Next, each region S including the light-emitting element 2 is filled with a resin composition for forming the resin layer 3, and the resin composition is cured by irradiation with ultraviolet rays, etc., so that the resin layer 3 is formed on the surface of the light-emitting element 2. A display device substrate 10 is obtained.
Note that part (one) or all of the two or more resin layers 3 may be a phosphor layer containing a phosphor.

As the partition wall composition for forming the partition walls 4, the same composition as the resin composition for forming the resin layer 3 described above can be applied.
Hereinafter, a method for manufacturing the display device substrate 10 when the resin composition forming the resin layer 3 is used as the partition composition forming the partition wall 4 will be described in more detail.

A resin composition is applied onto the substrate 1. Examples of the coating method include spin coating, slit coating, screen printing, inkjet coating, and bar coater coating.
The substrate coated with the resin composition is dried (prebaking). Examples of the prebaking method include drying under reduced pressure and drying by heating. Examples of the heating device include a hot plate, an oven, and the like.
The heating temperature during prebaking is preferably 60 to 150°C, more preferably 80 to 120°C. A stable coating film can be formed when the heating temperature during prebaking is within the above numerical range.
The heating time during pre-baking is preferably 30 seconds or more and 3 minutes or less. When the heating time during prebaking is within the above numerical range, a stable coating film can be formed.
The thickness of the coating film after prebaking is preferably 1 to 50 μm, more preferably 2 to 40 μm, and even more preferably 3 to 30 μm.

The coating film on the prebaked substrate is exposed to light and developed to obtain a substrate having a patterned coating film. Exposure may be performed through a desired mask or without a mask. The exposure machine is not particularly limited as long as it is equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a halogen lamp, etc., and irradiates ultraviolet rays, visible light, etc. in the range of 250 to 500 nm. Examples of the exposure machine include a stepper, a mirror projection mask aligner (MPA), a parallel light mask aligner (PLA), and the like.
The exposure intensity is preferably about 10 to 4000 J/m ² (converted to the exposure amount at a wavelength of 365 nm).
Examples of the exposure light source include ultraviolet light such as i-line, g-line, and h-line, KrF (wavelength: 248 nm) laser, ArF (wavelength: 193 nm) laser, and the like.

The coated film after exposure may be further heated. For example, the strength of the coating film can be further increased by heating at 50 to 150°C for 10 to 60 minutes.

Examples of methods for developing the coated film after exposure include showering, dipping, paddling, and the like.
The time period for which the coating film is brought into contact with the developer is preferably 5 seconds or more and 10 minutes or less.
Examples of the developer include an aqueous solution of an inorganic alkali, an aqueous solution of amines, an aqueous solution of a quaternary ammonium salt, and the like.
Examples of the inorganic alkali include alkali metal hydroxides, carbonates, phosphates, silicates, borates, and the like.
Examples of amines include 2-diethylaminoethanol, monoethanolamine, diethanolamine, and the like.
Examples of the quaternary ammonium salt include tetramethylammonium hydroxide and choline.

After development, the coating film is preferably rinsed with water.
Subsequently, dry baking may be performed at 50 to 140°C.

By heating the substrate having the patterned coating film obtained by development, a patterned processed substrate with the coating film cured is obtained.
Here, the patterned processed substrate refers to a substrate having a patterned cured film (wall).
Examples of the heating device include a hot plate, an oven, and the like.
The heating temperature is preferably 120 to 250°C, more preferably 200 to 250°C. When the heating temperature is equal to or higher than the above lower limit, the cured film can be sufficiently cured. When the heating temperature is below the above upper limit, thermal deterioration of the cured film can be suppressed.
The heating time is preferably 15 minutes or more and 2 hours or less, more preferably 20 minutes or more and 1 hour or less. When the heating time is at least the above lower limit, the cured film can be sufficiently cured. When the heating time is equal to or less than the above upper limit value, the productivity of the display device substrate 10 can be further improved.

A thin metal film of aluminum, nickel, or the like is formed to a predetermined thickness on the patterned surface of the obtained patterned processed substrate. The metal thin film may be formed by vapor deposition or electroless plating. When forming a metal thin film, mask the area where light will pass.
The thickness of the metal thin film is preferably 0.01 to 1 μm, more preferably 0.1 to 0.5 μm. When the thickness of the metal thin film is equal to or greater than the above lower limit, the reflectance of the partition wall 4 can be further increased. When the thickness of the metal thin film is equal to or less than the above upper limit value, the productivity of the display device substrate 10 can be further improved.
The thickness of the metal thin film is determined, for example, by observing a cross section of the display device substrate 10 in the thickness direction using a microscope or the like.

By forming the metal thin film, the partition wall 4 whose surface is coated with the metal thin film can be obtained. A light emitting element 2 is formed or arranged on the surface of the substrate 1 in each region S surrounded by the partition walls 4 of this partition-equipped substrate.
Next, each region S including the light emitting element 2 is filled with a resin composition for forming the resin layer 3 . Display in which a resin layer 3 is formed in each region S including the light emitting element 2 by exposing and heating a substrate filled with a resin composition in the same way as forming the cured film (wall) described above. A device substrate 10 is obtained.
The exposure machine, exposure intensity, and exposure light source are the same as those used for exposing the coating film described above.
The temperature at which the exposed resin composition is heated (hereinafter also referred to as "resin composition heating temperature") is preferably 120 to 250°C, more preferably 150 to 230°C. When the resin composition heating temperature is equal to or higher than the above lower limit, the resin composition can be sufficiently cured. When the resin composition heating temperature is below the above upper limit, thermal deterioration of the resin composition can be suppressed.
The heating time when heating the resin composition after exposure (hereinafter also referred to as "resin composition heating time") is preferably 15 minutes or more and 2 hours or less, more preferably 20 minutes or more and 1 hour or less. When the resin composition heating time is at least the above lower limit, the resin composition can be sufficiently cured. When the resin composition heating time is equal to or less than the above upper limit value, the productivity of the display device substrate 10 can be further improved.

Note that a phosphor is added to the resin composition forming the resin layer 3, and each region S including the light emitting element 2 is filled with this composition (hereinafter also referred to as "phosphor-containing resin composition"). , exposure, and heating, a display device substrate in which a phosphor layer is formed in each region S including the light emitting element 2 is obtained.

The phosphor-containing resin composition preferably contains a resin (dispersion) that disperses the phosphor. Examples of the resin used in the dispersion include silicone resins, epoxy resins, phenol resins, polycarbonate resins, acrylic resins, polynorbrunene resins, modified resins thereof, and hybrid resins. These resins are preferably made into a liquid dispersion as a liquid resin using monomers or organic solvents constituting the resins. By forming a liquid dispersion, the phosphor-containing resin composition can be applied to and filled into each region S including the light emitting element 2. Examples of devices for applying the phosphor-containing resin composition include devices such as a spin coater, a slit coater, a curtain coater, and an ink jet.

The content of the dispersion is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, and even more preferably 40 to 60% by mass, based on the total mass of the phosphor-containing resin composition. When the content of the dispersion is at least the above lower limit, the phosphor can be better dispersed. When the content of the dispersion is less than or equal to the above upper limit, the emission intensity of the phosphor layer can be further increased.

The content of the phosphor is preferably 5 to 50% by mass, more preferably 10 to 45% by mass, and even more preferably 15 to 30% by mass, based on the total mass of the phosphor-containing resin composition. When the content of the phosphor is equal to or higher than the above lower limit, the emission intensity of the phosphor layer can be further increased. When the content of the phosphor is equal to or less than the above upper limit, a decrease in transmittance and a decrease in brightness of the phosphor layer can be suppressed.

The content of the phosphor is preferably 5 to 50 parts by weight, more preferably 10 to 45 parts by weight, and even more preferably 20 to 40 parts by weight, based on 100 parts by weight of the resin (base resin) serving as the dispersion. When the content of the phosphor is equal to or higher than the above lower limit, the emission intensity of the phosphor layer can be further increased. When the content of the phosphor is equal to or less than the above upper limit, a decrease in transmittance and a decrease in brightness of the phosphor layer can be suppressed.

The exposure machine, exposure intensity, and exposure light source when exposing the phosphor-containing resin composition are the same as those used when exposing the coating film described above.
The temperature at which the phosphor-containing resin composition after exposure is heated (hereinafter also referred to as "phosphor-containing resin composition heating temperature") is preferably 120 to 250°C, more preferably 180 to 230°C. When the heating temperature of the phosphor-containing resin composition is equal to or higher than the above lower limit, the phosphor-containing resin composition can be sufficiently cured. When the phosphor-containing resin composition heating temperature is below the above upper limit, thermal deterioration of the phosphor-containing resin composition can be suppressed.
The heating time when heating the phosphor-containing resin composition after exposure (hereinafter also referred to as "phosphor-containing resin composition heating time") is preferably 15 minutes or more and 2 hours or less, and 30 minutes or more and 1 hour or less. is more preferable. When the phosphor-containing resin composition heating time is at least the above lower limit, the phosphor-containing resin composition can be sufficiently cured. When the phosphor-containing resin composition heating time is equal to or less than the above upper limit, the productivity of the display device substrate can be further improved.

[Image display device]
The image display device of the present invention includes the display device substrate of the present invention. Specific examples of image display devices include televisions, monitors, mobile phones, portable game devices, personal digital assistants, personal computers, electronic books, video cameras, digital still cameras, head-mounted displays, navigation systems, and sound playback devices. (car audio, digital audio player, etc.), copying machines, facsimile machines, printers, multifunction printers, vending machines, automatic teller machines (ATMs), personal authentication devices, optical communication devices, IC cards, etc.
These image display devices can be used in various applications. For example, two or more types of image display devices may be freely combined. Furthermore, an antenna can be further mounted on an electronic device equipped with an image display device to perform communication and contactless power reception and power supply.

Hereinafter, an image display device according to an embodiment of the present invention will be described in detail based on FIG. 2.
As shown in FIG. 2, the image display device 100 includes a substrate 1, a light emitting element 2, a resin layer 3, a partition wall 4, a transparent resin layer 5, a color filter layer 7, and a substrate 8. That is, the image display device 100 includes a display device substrate 10, and a transparent resin layer 5, a color filter layer 7, and a substrate 8 are arranged in this order on the resin layer 3 of the display device substrate 10 and the light emitting surface of the partition wall 4. It has a laminated structure. The color filter layer 7 has a color filter 6.
In this specification, the "image display device" may be only one image display device 100 (also referred to as a unit pixel), or may be one in which two or more unit pixels are arranged horizontally to form a matrix. It may be something that exists.

≪Transparent resin layer≫
The transparent resin layer 5 is located on the light emitting surface of the display device substrate 10. The transparent resin layer 5 is not particularly limited as long as it is a transparent layer that can bond the display device substrate 10 and the color filter layer 7 together.
Examples of the resin forming the transparent resin layer 5 include epoxy resins, phenol resins, polycarbonate resins, acrylic resins, polynorbornene resins, modified resins thereof, and hybrid resins thereof. As the resin forming the transparent resin layer 5, the silicone resin (A) described above may be used.
These resins are made into transparent resins by forming a liquid dispersion using monomers or organic solvents, then applying and curing the dispersion using equipment such as a spin coater, slit coater, curtain coater, or inkjet. Layer 5 can be formed.

The thickness T ₅ of the transparent resin layer 5 is, for example, preferably 0.1 to 5 μm, more preferably 0.5 to 3 μm, and even more preferably 1 to 2 μm. When the thickness T ₅ of the transparent resin layer 5 is equal to or greater than the above lower limit, the resin layer 3 can be sufficiently sealed. When the thickness T5 of the transparent resin layer ₅ is less than or equal to the above upper limit value, the light emission intensity of the image display device 100 can be further increased.
The thickness _T5 of the transparent resin layer 5 can be determined, for example, by observing a cross section of the image display device 100 in the thickness direction using a microscope or the like.

≪Color filter layer≫
The color filter layer 7 has a color filter 6. The color filter 6 regulates the wavelength range of light emitted from the resin layer 3 toward the substrate 8. The color filter 6 includes a color filter 6R, a color filter 6G, and a color filter 6B.
The color filter 6R restricts transmitted light to red light.
The color filter 6G restricts transmitted light to green light.
The color filter 6B restricts transmitted light to blue light.
The color filter 6R, the color filter 6G, and the color filter 6B may be separated from each other or may be adjacent to each other.

The thickness T ₇ of the color filter layer 7 is, for example, preferably 0.1 to 5 μm, more preferably 0.5 to 3 μm, and even more preferably 0.7 to 1.5 μm. When the thickness T ₇ of the color filter layer 7 is equal to or greater than the above lower limit value, the wavelength range of transmitted light can be more reliably regulated. When the thickness T ₇ of the color filter layer 7 is less than or equal to the above upper limit value, the transmittance of transmitted light can be further increased.
The thickness _T7 of the color filter layer 7 can be determined, for example, by observing a cross section of the image display device 100 in the thickness direction using a microscope or the like.

As the color filter 6, a color filter with any transmittance used in general image display devices can be used.
For example, the color filter 6R preferably has a transmittance of 5% or less for light having a wavelength of 380 nm or more and 580 nm or less.
The color filter 6G preferably has a transmittance of 5% or less for light having a wavelength of 380 nm or more and 480 nm or less.
The color filter 6B preferably has a transmittance of 5% or less for light having a wavelength of 480 nm or more and 780 nm or less.

The color filter 6 can be formed by dispersing an organic pigment in a transparent resin such as acrylic resin.
Examples of red organic pigments that can be applied to the color filter 6R include C.I. I. Pigment Red 7, 14, 41, 48:2, 48:3, 48:4, 81:1, 81:2, 81:3, 81:4, 146, 168, 177, 178, 179, 184, 185, Red pigments such as 187, 200, 202, 208, 210, 246, 254, 255, 264, 270, 272, 279 can be mentioned. In addition to the red pigment, a yellow pigment or an orange pigment can also be used in the color filter 6R.

For example, as a yellow organic pigment that can be applied to the color filter 6, C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35:1, 36, 36:1, 37, 37:1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 126, 127, 128, 129, 147, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, 187, 188, 193, 194, 199, 198, 213, 214, etc. are mentioned.

Examples of green organic pigments that can be applied to the color filter 6G include C.I. I. Examples include green pigments such as Pigment Green 7, 10, 36, and 37. Moreover, a halogenated zinc phthalocyanine green pigment or a halogenated aluminum phthalocyanine green pigment can also be suitably used for the color filter 6G.
In addition to the green pigment, the above-mentioned yellow pigment can also be used in the color filter 6G.

Examples of blue organic pigments that can be applied to the color filter 6B include C.I. I. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 60, 64 and the like can be mentioned.
In addition to the blue pigment, a purple pigment can also be used in the color filter 6B. As a purple pigment, C. I. Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, 50, and the like.

These organic pigments are used by being dispersed in a transparent resin together with an organic solvent and a dispersant. The transparent resin is more preferably a transparent resin having a transmittance in the visible range of 90% or more, and more preferably an alkali-soluble photosensitive resin containing a resin precursor.
When manufacturing the color filter 6, the organic pigment can be contained in a range of 15% by mass to 60% by mass based on the transparent resin.

The photosensitive resin suitable for the color filter 6 is a linear polymer having a reactive substituent such as an isocyanate group, an aldehyde group, or an epoxy group in a linear polymer having a reactive substituent such as a hydroxyl group, a carboxyl group, or an amino group. Examples include resins in which a photocrosslinkable group such as a (meth)acryloyl group or a styryl group is introduced into the linear polymer by reacting a meth)acrylic compound or cinnamic acid.

Monomers and oligomers that are precursors of transparent resin suitable for the color filter 6 include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, cyclohexyl (meth)acrylate, and polyethylene glycol di(meth)acrylate. , pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tricyclodecanyl(meth)acrylate, melamine(meth)acrylate, epoxy(meth)acrylate, etc. Examples include acrylic esters and methacrylic esters, (meth)acrylic acid, styrene, vinyl acetate, (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, and acrylonitrile. These can be used alone or in combination of two or more.
When a transparent resin in which an organic pigment is dispersed is cured by, for example, irradiation with ultraviolet light having a wavelength of 365 nm, a photopolymerization initiator or the like is further added.

The color filter layer 7 may be formed of the above-mentioned transparent resin in addition to the color filter 6.

≪Substrate≫
The substrate 8 is located at the outermost layer of the light emitting surface of the image display device 100.
Examples of the substrate 8 include a glass plate similar to the substrate 1, a resin plate, a resin film, and the like. The type of substrate 8 may be the same as the type of substrate 1, or may be different.
The thickness T ₈ of the substrate 8 is, for example, similar to the thickness T ₁ of the substrate 1. The thickness T ₈ of the substrate 8 may be the same as the thickness T ₁ of the substrate 1 or may be different.

[Method for manufacturing image display device]
The image display device 100 is not particularly limited as long as the above structure can be formed.
For example, a color filter layer composition for forming the color filter layer 7 is applied to the surface of the substrate 8 and cured to obtain a substrate with a color filter layer.
Next, a transparent resin layer composition for forming the transparent resin layer 5 is applied to the light emitting surface of the display substrate 10, and the color filter layer side surface of the substrate with a color filter layer is laminated with the transparent resin layer composition. Then, the transparent resin layer composition is cured by irradiation with ultraviolet rays or the like, thereby obtaining an image display device 100 in which a substrate with a color filter layer is laminated on the light emitting surface of the display device substrate 10 with the transparent resin layer 5 interposed therebetween. .

Note that part or all of the resin layer 3 may be a phosphor layer containing a phosphor.
For example, a resin layer facing the color filter 6R may contain a phosphor to form a phosphor layer 9R.
The resin layer facing the color filter 6B may contain a phosphor to form the phosphor layer 9G.
By using the phosphor layer 9 as the resin layer 3, the light emitting characteristics of the image display device 100 can be further improved.

According to the display device substrate of this embodiment, since a silicone resin having a specific structure is used in the resin layer, it has high transparency and is excellent in heat resistance and yellowing resistance.

Although each embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and changes and combinations of the configuration can be made without departing from the gist of the present invention. included.
For example, although the display device substrate of this embodiment has one unit pixel, the number of unit pixels may be two or more.
For example, although the display device substrate of this embodiment does not have a color filter layer, the display device substrate may have a color filter layer.
For example, although the image display device of this embodiment has one unit pixel, the number of unit pixels may be two or more.
For example, although the image display device of this embodiment has a phosphor layer, the image display device does not need to have a phosphor layer.

The present invention will be explained in more detail below using Examples, but the present invention is not limited to these Examples.

A blue LED with an emission peak wavelength of 385 nm was used as a light emitting element.
Eu ²⁺ activated CASN phosphor was used as the phosphor (red).
As the phosphor (green), Eu ²⁺ activated (Ba, Sr) GaS phosphor was used.
A phosphor-containing resin composition was prepared by using a silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd.) as a base material for a resin composition forming a resin layer and dispersing a phosphor therein. In addition, in the comparative example, acrylic resin (manufactured by Sumitomo Chemical Co., Ltd.) was used as the base material of the resin composition.

Using a spin coater (manufactured by Mikasa Co., Ltd.), the resin composition was applied onto a 10 cm square alkali-free glass substrate so that the film thickness after curing was 20 μm, and a hot plate (manufactured by As One Co., Ltd.) was applied. A prebaked film was formed by prebaking at a temperature of 100° C. for 3 minutes. The prepared prebaked film was exposed to light using a parallel light mask aligner (manufactured by Topcon Corporation) using an ultra-high pressure mercury lamp as a light source, without using a mask, at an exposure dose of 200 mJ/cm ² (ghi line) with a gap of 100 μm. did. Thereafter, using an automatic developing device ("AD-1200 (trade name)" manufactured by Mikasa Co., Ltd.), shower development was performed for 30 seconds using a 0.5% by weight sodium hydroxide aqueous solution, and then for 15 seconds using water. I rinsed it. The rinsed substrate was dried at 230° C. for 30 minutes to obtain a resin layer.

[Example 1, Comparative Example 1]
Regarding the resin layer obtained above, the transmittance at 385 nm was measured using an ultraviolet-visible spectrophotometer (manufactured by Hitachi High-Tech Corporation) (initial stage).
Next, the substrate on which the resin layer was formed was placed in an oven (manufactured by Yamato Scientific Co., Ltd.) and heated at a temperature of 150° C. for 500 hours. After the substrate was allowed to stand overnight at room temperature (15 to 25° C.), the transmittance at 385 nm and yellowness were measured using the ultraviolet-visible spectrophotometer described above (after heating). From the obtained transmittance values, the transmittance difference and transmittance retention were calculated, and the results are shown in Table 1.

Further, a graph of the transmission spectra (after heating) of Example 1 and Comparative Example 1 is shown in FIG.
As shown in FIG. 3, the transmittance of Example 1 exceeded the transmittance of Comparative Example 1 in the region of about 550 nm or less. This means that the resin layer of Example 1 has higher transparency and better heat resistance and yellowing resistance than the resin layer of Comparative Example 1.

[Examples 2-3, Comparative Examples 2-3]
The phosphor (red) was pulverized to adjust the particle size, and the phosphor was dispersed in a resin serving as a base material (base resin) at the ratio shown in Table 1 to obtain a phosphor layer in the same manner as in Example 1. The dispersed particle size of the phosphor (red) was calculated as the particle size at an integrated value of 50% in the particle size distribution determined by the photon correlation method. Regarding the obtained phosphor layer, the initial transmittance and the transmittance after heating were measured in the same manner as in Example 1, and the transmittance difference and transmittance retention rate were calculated. The results are shown in Table 1.

[Examples 4-5, Comparative Examples 4-5]
The phosphor (green) was pulverized to adjust the particle size, and the phosphor was dispersed in a resin serving as a base material (base resin) at the ratio shown in Table 1 to obtain a phosphor layer in the same manner as in Example 1. The dispersed particle size of the phosphor (green) was calculated as the particle size at an integrated value of 50% in the particle size distribution determined by the photon correlation method. Regarding the obtained phosphor layer, the initial transmittance and the transmittance after heating were measured in the same manner as in Example 1, and the transmittance difference and transmittance retention rate were calculated. The results are shown in Table 1.

<Measurement of luminescence characteristics (450nm)>
The emission characteristics were measured using an integrating sphere attached to an ultraviolet-visible spectrophotometer (manufactured by Hitachi High-Tech Corporation). Measurement light with a wavelength of 450 nm that has passed through the phosphor layer of each example is irradiated onto an integrating sphere and passed through a detector to measure quantum yield (PLQY: Photoluminescence Quantum Yield), absorbance (Abs), peak wavelength (λ _max (nm)), The peak intensity (au (arbitrary unit)), half width (nm), and optical density (OD value) were determined. The results are shown in Table 1.
In this specification, optical density (OD value) means a value represented by the following formula (III).
OD value=-log( _IT / _IO )...(III)
In formula (III), I _O represents the incident light intensity (au) to the measurement target, and I _T represents the transmitted light intensity (au).

<Measurement of luminescence characteristics (385 nm)>
The emission characteristics were measured using an integrating sphere attached to an ultraviolet-visible spectrophotometer (manufactured by Hitachi High-Tech Corporation). Measurement light with a wavelength of 385 nm that has passed through the phosphor layer of each example is irradiated onto an integrating sphere, and passed through a detector to measure quantum yield (PLQY), absorbance (Abs), peak wavelength (λ _max (nm)), and peak intensity (a .u.), half width (nm), and optical density (OD value) were determined. The results are shown in Table 1.

<Measurement of front brightness>
Using a planar light emitting device (manufactured by MUTOH Holdings Co., Ltd.) equipped with a blue LED with an emission peak wavelength of 455 nm as a light source as an LED element, the substrate of each example was placed in the planar light emitting device with the phosphor layer facing the light source side. installed on top. A current was applied to this planar light emitting device to light up the LED elements, and the brightness (unit: cd/m ² ) was measured based on the CIE1931 standard using a spectral radiance meter (CS-1000, manufactured by Konica Minolta). , the initial brightness. Based on the obtained initial brightness, the peak intensity (au) and optical density (OD value) of the phosphor layer of each example were determined. The results are shown in Table 1.

FIG. 4 shows transmission spectra of transmittance after heating in the phosphor layers of Example 2, Comparative Example 2, Example 4, and Comparative Example 4.
As shown in FIG. 4, it was found that the transmittance at a wavelength of 385 nm was higher in Example 2 than in Comparative Example 2. Similarly, it was found that the transmittance at a wavelength of 385 nm was higher in Example 4 than in Comparative Example 4.

FIG. 5 shows the excitation spectrum and fluorescence spectrum of the phosphor (green) used in this example. The vertical axis of the graph in FIG. 5 represents fluorescence intensity (au).
As shown in FIG. 5, it can be seen that the phosphor (green) used in this example has a fluorescence peak wavelength (λ _max ) near a wavelength of 530 nm.

FIG. 6 shows the excitation spectrum and fluorescence spectrum of the phosphor (red) used in this example. The vertical axis of the graph in FIG. 6 represents fluorescence intensity (au).
As shown in FIG. 6, it can be seen that the phosphor (red) used in this example has a fluorescence peak wavelength (λ _max ) near a wavelength of 620 nm.

As shown in Table 1, Example 1 to which the present invention was applied had a transmittance of 95% or more after heating, and had higher transparency than Comparative Example 1, which used acrylic resin as the base resin. , heat resistance and yellowing resistance were found to be excellent.
It was found that Example 2 to which the present invention was applied had a higher transmittance after heating and was superior in heat resistance and yellowing resistance compared to Comparative Example 2 in which an acrylic resin was used as the base resin.
It was found that Example 3 to which the present invention was applied had a higher transmittance after heating and was superior in heat resistance and yellowing resistance compared to Comparative Example 3 in which an acrylic resin was used as the base resin.
It was found that Example 4 to which the present invention was applied had a higher transmittance after heating and was superior in heat resistance and yellowing resistance compared to Comparative Example 4 in which an acrylic resin was used as the base resin.
It was found that Example 5 to which the present invention was applied had a higher transmittance after heating and was superior in heat resistance and yellowing resistance compared to Comparative Example 5 in which an acrylic resin was used as the base resin.
From the above results, it was found that Examples 1 to 5 to which the present invention was applied had high transparency as substrates for display devices, and were superior in heat resistance and yellowing resistance.

1 Substrate 2 Light emitting element 3 Resin layer 4 Partition 5 Transparent resin layer 6 Color filter 7 Color filter layer 8 Substrate 10 Display device substrate 100 Image display device S region

Claims (8)

A substrate on which two or more light emitting elements that emit light in the near ultraviolet or blue wavelength band are arranged;
a partition wall surrounding each of the light emitting elements;
A display device substrate comprising a resin layer located on a surface of the light emitting element,
The resin layer is a cured product of a resin composition containing a silicone resin (A),
The silicone resin (A) contains 40 to 80 mol% of repeating units represented by the following formula (ia) based on the total number of repeating units constituting the silicone resin (A), a substrate for a display device. .

[In formula (ia), R is a hydrogen atom or a monovalent to trivalent hydrocarbon group having 1 to 30 carbon atoms, and the hydrocarbon group may be aliphatic or aromatic, and may be saturated or unsaturated. Often, the hydrocarbon group may be linear, branched, or cyclic, and when the number of carbon atoms in the hydrocarbon group is 2 or more, one or more methylene groups in the hydrocarbon group are unsubstituted or oxygen, imide group, or carbonyl group. one or more hydrogens in the hydrocarbon group are unsubstituted, or substituted with fluorine, a hydroxyl group, or an alkoxy group having 1 to 20 carbon atoms, and one or more carbons are unsubstituted, or When the hydrocarbon group is substituted with silicon and is divalent or trivalent, the hydrocarbon group connects Si contained in a plurality of repeating units. ] The display device substrate according to claim 1, wherein part or all of the resin layer is a phosphor layer further containing a phosphor. 3. The display device substrate according to claim 2, wherein the phosphor has europium at its emission center. 4. The display device substrate according to claim 2, wherein the phosphor can be excited by a blue light source with a wavelength of 380 to 480 nm, and has a peak wavelength of a fluorescence spectrum in a range of 400 to 700 nm. 5. The display device substrate according to claim 2, wherein the content of the phosphor is 20 to 70% by mass based on the total mass of the phosphor layer. The display device substrate according to any one of claims 2 to 5, wherein the phosphor layer further includes quantum dots. The display device substrate according to claim 1, wherein the resin layer has a thickness of 1 to 50 μm. An image display device comprising the display device substrate according to any one of claims 1 to 7.

Images