Display substrate and image display device

Abstract

A substrate for a display device comprises: a substrate having two or more light-emitting elements 2 disposed thereon, which emit light in the near-ultraviolet or blue wavelength band; a partition wall surrounding each of the light-emitting elements; and a resin layer located on the surface of the light-emitting elements, wherein the resin layer is a cured material of a resin composition comprising silicone resin (A), wherein the silicone resin (A) contains 40 to 80 moles of repeating units represented by a specific structure relative to the total number of repeating units constituting the silicone resin (A).

Description

Technical Field

[0001] This invention relates to a substrate for a display device and an image display device. This application claims priority to Japanese Patent Application No. 2022-031426, filed on March 2, 2022, the contents of which are incorporated herein by reference. Prior Technology

[0002] In recent years, light-emitting diodes (LEDs) have become increasingly widespread. LEDs are used in displays for televisions, personal computers, tablets, smartphones, and in lighting. Image display devices using LEDs can display images without the need for liquid crystals that switch between transmitting and blocking light. Therefore, image display devices using LEDs offer significantly better visibility in the dark compared to liquid crystal displays, which suffer from light leakage when displaying black.

[0003] Micro LEDs are image display devices that have a matrix structure of LED chips with a size of about 2μm to 50μm, and display by individually driving each of the plurality of LED chips. Such micro LEDs can display without the use of liquid crystals.

[0004] Micro LEDs are broadly categorized into two types: those using red, green, and blue LED elements; and those using monochromatic LED elements, such as LED chips that emit light in the blue to near-ultraviolet wavelength range. In micro LEDs, each LED element functions as a display layer. While using red, green, and blue LED elements offers advantages such as excellent brightness and lifespan, it also has disadvantages including more complex and costly manufacturing processes for installing LEDs of different colors, and the difficulty in controlling the different driving voltages required for each.

[0005] In the use of monochromatic LED elements, a wavelength conversion layer (e.g., a dispersion of quantum dots or inorganic phosphors) is stacked on each of a plurality of monochromatic LED elements to convert the emitted wavelength to any one of red, green, or blue, in order to achieve color display.

[0006] For example, Patent Document 1 proposes an image display device in which the excitation light is ultraviolet light (e.g., a monochromatic light source in the purple or ultraviolet region), and has a color conversion layer (resin layer) that converts the excitation light into red, green or blue light.

[0007] The resin layer used in image display devices requires heat resistance and resistance to yellowing in order to maintain high transparency. To address such issues, for example, Patent Document 2 proposes a photocrosslinkable resin composition with an acrylic resin having alicyclic epoxy groups and a photocationic polymerizer as essential components. According to the invention in Patent Document 2, improvements in weather resistance, yellowing resistance, etc., can be achieved. Patent Document 3 proposes a semiconductor wafer using a silicone resin with a dimethylsiloxane backbone in a sealing material. According to the invention in Patent Document 3, it is possible to improve the transparency of the sealing material. [Previous Technical Documents] [Patent Literature]

[0008] [Patent Document 1] International Publication No. 2019-159702 [Patent Document 2] Japanese Patent Application Publication No. 2-289611 [Patent Document 3] Japanese Patent Application Publication No. 2003-273292 Summary of the Invention

[0009] [The problem the invention aims to solve]

[0010] However, the resins used in Patent Documents 2 and 3 deteriorate further due to ultraviolet light and heat from the light-emitting element, making it impossible to maintain high transparency, and their heat resistance and yellowing resistance are not sufficient.

[0011] Therefore, the present invention aims to provide a display device substrate and an image display device with superior transparency, heat resistance, and yellowing resistance. [Methods used to solve problems]

[0012] Through dedicated research, the inventors discovered that the aforementioned 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 state.

[0013] The first embodiment of the present invention is a display device substrate comprising a substrate having two or more light-emitting elements that emit light in the near-ultraviolet or blue wavelength band, a partition wall surrounding each of the light-emitting elements, and a resin layer located on the surface of the light-emitting elements. The resin layer is a cured form of a resin composition containing silicone resin (A), wherein the silicone resin (A) contains 40 to 80 moles of repeating units represented by the following formula (ia) relative to the total number of repeating units constituting the silicone resin (A). [In formula (ia), R is a hydrogen atom or a hydrocarbon group with 1 to 30 carbon atoms and a valence of 1 to 3. The aforementioned hydrocarbon group can be aliphatic or aromatic, saturated or unsaturated, and linear, branched, or cyclic. If the aforementioned hydrocarbon group has 2 or more carbon atoms, one or more methylene groups in the aforementioned hydrocarbon group are unsubstituted or substituted by oxygen, amide, or carbonyl groups. One or more hydrogen groups in the aforementioned hydrocarbon group are unsubstituted or substituted by fluorine, hydroxyl, or alkoxy groups with 1 to 20 carbon atoms, and one or more carbon atoms are unsubstituted or substituted by silicon. If the aforementioned hydrocarbon group is divalent or trivalent, the aforementioned hydrocarbon group links the Si atoms contained in the plurality of repeating units to each other.] The substrate for a display device of the second aspect of the present invention is, in the first aspect described above, a portion or all of the aforementioned resin layer may be a phosphor layer further comprising phosphors. The third embodiment of the present invention is a display device substrate in the second embodiment described above, wherein the aforementioned phosphor may have europium at the light-emitting center. The fourth state of the present invention is a display device substrate in which the aforementioned phosphor can be excited by a blue light source with a wavelength of 380 to 480 nm in the second state or the third state, and the peak wavelength of the fluorescence spectrum can be in the range of 400 to 700 nm. The fifth state sample of the present invention is a display device substrate in any of the second to fourth states, wherein the content of the phosphor can be 20 to 70% by mass relative to the total mass of the phosphor layer. The sixth state of the present invention is a display device substrate in any one of the second to fifth states, wherein the phosphor layer may further include quantum dots. The substrate for a display device of the seventh state of the present invention is in any one of the states from the first state to the sixth state, wherein the thickness of the aforementioned resin layer may be 1 to 50 μm.

[0014] The image display device of the eighth state of the present invention includes a display device substrate of any one of the first state to the seventh state. [Effects of the Invention]

[0015] The display device substrate and image display device according to the present invention have high transparency and superior heat resistance and yellowing resistance. Simple Explanation of the Diagram

[0016] Figure 1 is a cross-sectional view of a substrate for a display device according to one embodiment of the present invention. Figure 2 is a cross-sectional view of an image display device according to one embodiment of the present invention. Figure 3 is a graph showing the transmission spectra of Example 1 and Comparative Example 1. Figure 4 is a graph showing the transmission spectra of Example 2, Comparative Example 2, Example 4 and Comparative Example 4. Figure 5 shows the excitation and fluorescence spectra of a phosphor that emits green light. Figure 6 shows the excitation and fluorescence spectra of a phosphor that emits red light. Implementation

[0017] [The form in which the invention is carried out]

[0018] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same element symbols will be used for the same or substantially the same functions and constituent elements, and their descriptions will be omitted or simplified, or only described where necessary. In each figure, each constituent element will be set to the degree of its recognizability in the drawings. In addition, elements that are difficult to illustrate, such as the structure of thin-film transistors, the structure of multiple layers constituting the conductive layer, the wiring connection of the circuit section, the switching element (transistor), etc., will be omitted as needed.

[0019] [Display device substrate] Hereinafter, a display device substrate according to one embodiment of the present invention will be described in detail based on FIG1. As shown in Figure 1, the display device substrate 10 includes: a substrate 1, a light-emitting element 2, a resin layer 3, and a partition 4. The light-emitting element 2 is disposed on the substrate 1 and surrounded by the partition 4. The resin layer 3 is located on the surface of the light-emitting element 2 and is formed within the region S surrounded by the partition 4. In this embodiment, each region S is divided by a partition wall 4 set between adjacent light-emitting elements 2. In this specification, "display device substrate" may be only one display device substrate 10 (also called "unit pixel"), or it may be a substrate in which two or more unit pixels are arranged in a horizontal direction to form a matrix.

[0020] 《Substrate》 Examples of substrate 1 include glass plates, resin plates, and resin films. As materials for glass sheets, examples include soda lime glass and alkali-free glass, with alkali-free glass being the preferred choice. Examples of materials used for resin boards and resin films include polyester, (meth)acrylic polymers, polyimide, and polyether ether. Here, "(meth)acrylic polymers" is a general term for both acrylic polymers and methacrylic polymers. The thickness T1 of substrate 1 is preferably 1 mm or less, more preferably 0.8 mm or less, and even more preferably 0.1 mm or less. If the thickness T1 of substrate 1 is below the above-mentioned upper limit value, the substrate 10 for the display device can be made lighter. The lower limit value of the thickness T1 of substrate 1 is not particularly limited, but for example, the lower limit value of the thickness T1 of substrate 1 is 0.01 mm.

[0021] Light-emitting elements For light-emitting element 2, multiple light-emitting diodes called LEDs (Light Emitting Diodes) can be used. LED chips and light-emitting diode elements refer to LEDs; in the following description, there are instances where they are referred to only as LEDs.

[0022] For LEDs, compounds such as aluminum gallium arsenide (AlGaAs), gallium arsenide phosphide (GaAsP), indium gallium nitride (InGaN) / gallium nitride (GaN) / aluminum gallium nitride (AlGaN), gallium phosphide (GaP), zinc selenide (ZnSe), and aluminum indium gallium phosphide (AlGaInP) are suitable. The light-emitting element 2 in this embodiment emits light in the near-ultraviolet or blue wavelength range. The light-emitting element 2 is a monochromatic LED, with gallium nitride (GaN) as the main material.

[0023] In this specification, the term "blue" refers to light with a wavelength range of 410 nm to 490 nm. A "blue LED" (a blue-emitting LED) is an LED that has a emission peak within the wavelength range of 410 nm to 490 nm. In embodiments of the present invention, the term "near-ultraviolet light" refers to light with a wavelength range of 300 nm to 410 nm (violet to near-ultraviolet emission). A "near-ultraviolet LED" is an LED that has a emission peak within the wavelength range of 300 nm to 410 nm. In this specification, a monochromatic LED is defined as an LED with a half-width at half-maximum (FWHM) of less than 70 nm and a single emission peak within the aforementioned wavelength range. A smaller FWHM is preferred.

[0024] In micro LED displays, LED elements (LED chips) with dimensions ranging from 2 μm to 50 μm can be used. The LED element can be constructed using a horizontal LED with the n-side electrode and p-side electrode located on the same side, or a vertical LED with the n-side electrode and p-side electrode located on different surfaces (parallel surfaces facing each other) in the thickness direction of the LED. In the following description, the upper electrode and lower electrode refer to either the n-side electrode or the p-side electrode of the vertical LED.

[0025] Resin Layer Resin layer 3 is a cured resin composition containing silicone resin (A). The resin composition forming resin layer 3 includes silicone resin (A). Among the resin compositions, silicone resin (A) is preferred as the base material. In this specification, the term "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 20-80% by mass, more preferably 30-70% by mass, and even more preferably 40-60% by mass, relative to the total mass of the resin composition. If the content of silicone resin (A) is above the lower limit mentioned above, the heat resistance and yellowing resistance of the resin layer 3 can be further improved. If the content of silicone resin (A) is below the upper limit mentioned above, the transparency of the resin layer 3 can be further improved.

[0026] Silicone resins are resins with siloxane bonds (Si-O-Si bonds) as the main chain. The silicone resin (A) of this embodiment contains repeating units represented by the following formula (ia).

[0027]

[0028] In formula (ia), R is a hydrogen atom or a hydrocarbon group with 1 to 30 carbon atoms and a valence of 1 to 3. The hydrocarbon group can be aliphatic or aromatic, saturated or unsaturated, and linear, branched, or cyclic. If the hydrocarbon group has two or more carbon atoms, one or more methylene groups can be unsubstituted, or substituted with oxygen, amide, or carbonyl groups. If the hydrocarbon group has two or more carbon atoms, one or more hydrogen atoms can be unsubstituted, or substituted with fluorine, hydroxyl, or alkoxy groups with 1 to 20 carbon atoms. If the hydrocarbon group has two or more carbon atoms, one or more carbon atoms can be unsubstituted, or substituted with silicon. If the hydrocarbon group is divalent or trivalent, the hydrocarbon group can link the Si atoms contained in multiple repeating units together.

[0029] 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.

[0030] When the hydrogen in the hydrocarbon group is substituted by an alkoxy group, the carbon number of the alkoxy group is preferably 1 to 20, and more preferably 1 to 6.

[0031] The repeating unit represented by formula (ia) is a silsesquioxane structural unit. Silsesquioxanes are network polymers or polyhedral aggregates with a (RSiO 1.5)n (n is a natural number) structure obtained by hydrolyzing trifunctional silanes. Each silicon atom is bonded to an average of 1.5 oxygen atoms and 1 hydrocarbon group. They are inorganic compounds with a cage-like framework composed of up to 8 organic functional groups and Si-O bonds. Silsesquioxanes are compounds with an intermediate stoichiometry between silicon oxide (SiO₂) and silicone (R₂SiO), and are inorganic compounds with an affinity for organic matter. Silicone resin (A) has superior heat resistance and yellowing resistance due to its silsesquioxane structural units.

[0032] The content of silsesquioxane structural units is 40-80 mol%, preferably 45-75 mol%, and more preferably 50-70 mol%, relative to the total number of repeating units constituting silicone resin (A). If the content of silsesquioxane structural units is above the lower limit mentioned above, the heat resistance and yellowing resistance of the resin layer 3 can be further improved. If the content of silsesquioxane structural units is below the upper limit mentioned above, when the resin layer 3 contains the phosphor described later, the luminescence of the phosphor can be unimpeded, further improving the heat resistance and yellowing resistance of the resin layer 3. The content of silsesquioxane structural units can be determined, for example, by gas chromatography (GC) or liquid chromatography (LC).

[0033] Silicone resin (A) may contain repeating units represented by the following formula (ib).

[0034]

[0035] The content of repeating units represented by formula (ib) is relative to the total number of repeating units constituting silicone resin (A), and is preferably 40 mol% or less, more preferably 10 to 20 mol%. If the content of repeating units represented by formula (ib) is above or above the lower limit mentioned above, the heat resistance and yellowing resistance of the resin layer 3 can be further improved. If the content of repeating units represented by formula (ib) is below or above the upper limit mentioned above, the transparency of the resin layer 3 can be further improved. The content of repeating units represented by formula (ib) can be determined, for example, by gas chromatography, liquid chromatography, etc.

[0036] Silicone resin (A) may contain repeating units represented by formula (ia) and repeating units other than those represented by formula (ib) (hereinafter also referred to as "other repeating units"). Examples of other repeating units include repeating units derived from vinyl compounds, repeating units derived from acrylic compounds, and repeating units derived from polyester compounds. The content of other repeating units is preferably 1 mol% or less, and more preferably 0 mol%, relative to the total number of repeating units constituting silicone resin (A). If the content of other repeating units is below the above-mentioned upper limit, the organic matter content of resin layer 3 can be reduced, and the heat resistance and yellowing resistance of resin layer 3 can be further improved. The content of other repeating units can be determined, for example, by gas chromatography, liquid chromatography, etc.

[0037] The average molecular weight of the silicone resin (A) is preferably 500-25,000, more preferably 1,000-20,000. If the average molecular weight of the silicone resin (A) is above the lower limit mentioned above, the heat resistance and yellowing resistance of the resin layer 3 can be further improved. If the average molecular weight of the silicone resin (A) is below the upper limit mentioned above, the transparency of the resin layer 3 can be further improved. In this specification, the mass-average molecular weight refers to the mass-average molecular weight converted from polystyrene, which is determined using gel permeation chromatography (GPC) with polystyrene as the reference material.

[0038] Examples of monomers for silicone resin (A) include pentacyclic [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), pentacyclic [9.5.1.13,9.15, 15.17,13]octasiloxane, and 1,3,5,7,9,13-hexamethyl-11,15-diphenyl- (CAS No. 18421-62-0), which are fully cage-like silsesquioxanes.

[0039] The resin composition forming resin layer 3 may contain components other than silicone resin (A). Examples of components other than silicone resin (A) include photopolymerization initiators (B), photopolymerizable compounds (C), and organic solvents (D).

[0040] Photopolymerization initiator (B) is a compound that generates free radicals when exposed to ultraviolet light. Examples of photopolymerization initiators (B) include benzoin derivatives (benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, etc., benzoin alkyl ethers), phenyl ketones [e.g., acetophenones (e.g., acetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, etc.), alkyl phenyl ketones such as 2-hydroxy-2-methylphenylpropanone; cycloalkyl phenyl ketones such as 1-hydroxycyclohexylphenyl ketone, etc.], and aminoacetophenones {2-methyl-1-[4-(methylthio)phenyl]-2- linylaminoacetone-1,2-benzyl-2-dimethylamino-1-(4- Examples of photopolymerization initiators (B) include: linylphenyl-1-butanone, anthraquinones (anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-trimethylbutylanthraquinone, 1-chloroanthraquinone, etc.), oxysulfur derivatives (2,4-dimethyloxysulfur, 2,4-diethyloxysulfur, 2-chlorooxysulfur, 2,4-diisopropyloxysulfur, etc.), ketals (acetophenone dimethyl ketal, benzyl dimethyl ketal, etc.), benzophenones (benzophenone, etc.), xanthraquinones, and phosphine oxides (e.g., 2,4,6-trimethylbenzoyldiphenylphosphine oxide, etc.). These photopolymerization initiators (B) can be used alone or in combination of two or more.

[0041] The content of the photopolymerization initiator (B) is preferably 0.01 to 20% by mass, more preferably 0.1 to 5% by mass, relative to the total mass of the resin composition forming the resin layer 3. If the content of the photopolymerization initiator (B) is above the lower limit mentioned above, the resin composition forming the resin layer 3 can be sufficiently cured. If the content of the photopolymerization initiator (B) is below the upper limit mentioned above, unreacted photopolymerization initiator (B) is unlikely to remain, which can further improve the transparency of the resin layer 3.

[0042] Photopolymerizable compound (C) is a resin that polymerizes and hardens when exposed to active energy lines such as ultraviolet light. As photopolymerizable compound (C), monofunctional, difunctional, or trifunctional (meth)acrylate monomers can be used. Furthermore, in this specification, "(meth)acrylate" is a general term for both acrylate and methacrylate, and "(meth)acryl" is a general term for both acrylonitrile and methacryl.

[0043] Examples of monofunctional (meth)acrylate compounds include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tributyl (meth)acrylate, glycidyl (meth)acrylate, and acrylamide. Phosphorus, N-vinylpyrrolidone, Tetrahydrofuran methyl acrylate, Cyclohexyl methacrylate, 2-Ethylhexyl methacrylate, Isobornyl methacrylate, Isodecyl methacrylate, Lauryl methacrylate, Tridecyl methacrylate, Cetyl methacrylate, Stearyl methacrylate, Benzyl methacrylate, 2-Ethoxyethyl methacrylate, 3-Methoxybutyl methacrylate, Ethyl carbitol methacrylate, Phosphate methacrylate, Ethylene oxide modified phosphate methacrylate, Phenoxy methacrylate, 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, Methoxy Diethylene glycol (meth)acrylate, methoxy polyethylene glycol (meth)acrylate, methoxypropylene glycol (meth)acrylate, 2-(meth)propenyloxyethyl-2-hydroxypropyl phthalate, (meth)acrylate-2-hydroxy-3-phenoxypropyl ester, 2-(meth)propenyloxyethyl hydrogenated phthalate, 2-(meth)propenyloxypropyl hydrogenated phthalate, 2-(meth)propenyloxypropyl hexahydrogenated phthalate, 2-(meth)propenyloxypropyl tetrahydrogenated phthalate, (meth)acrylate dimethylaminoethyl, (meth)acrylate trifluoroethyl, (meth)acrylate tetrafluoropropyl, (meth)acrylate hexafluoropropyl, (meth)acrylate octafluoropropyl, (meth)acrylate octafluoropropyl, adamantane derivatives of mono(meth)acrylates derived from 2-adamantane and adamantanediol, etc.

[0044] 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, nonanediol di(meth)acrylate, ethylene glycol di(meth)acrylate oxyhexanediol di(meth)acrylate, propionyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene glycol neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, hydroxypentyl acid neopentyl glycol di(meth)acrylate, etc.

[0045] Examples of trifunctional or higher (meth)acrylate compounds include trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, tri-2-hydroxyethyl isocyanate tri(meth)acrylate, glycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, etc., which are trifunctional (meth)acrylates. Polyfunctional (meth)acrylate compounds with three or more functions, such as acrylate compounds, pentaerythritol tetra(meth)acrylate, di(trimethylolpropane)tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, di(trimethylolpropane) penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and di(trimethylolpropane) hexa(meth)acrylate, and polyfunctional (meth)acrylate compounds in which a portion of these (meth)acrylates is replaced by alkyl groups or ε-caprolactones, etc.

[0046] Furthermore, urethane (meth)acrylates can also be used as photopolymerizable compounds (C). Examples of urethane (meth)acrylates include compounds obtained by reacting a hydroxyl-containing (meth)acrylate monomer with a product obtained by reacting an isocyanate monomer or a prepolymer with a polyester polyol.

[0047] Examples of methacrylates include pentaerythritol triacrylate hexamethylene diisocyanate methacrylate prepolymer, pentaerythritol pentaacrylate hexamethylene diisocyanate methacrylate prepolymer, pentaerythritol triacrylate toluene diisocyanate methacrylate prepolymer, pentaerythritol pentaacrylate toluene diisocyanate methacrylate prepolymer, pentaerythritol triacrylate isoflavone diisocyanate methacrylate prepolymer, and pentaerythritol pentaacrylate isoflavone diisocyanate methacrylate prepolymer.

[0048] The aforementioned (meth)acrylate compounds can be used alone or in combination of two or more. Furthermore, the aforementioned (meth)acrylate compounds can be monomers or partially polymerized oligomers in the coloring layer forming composition.

[0049] The content of the photopolymerizable compound (C) is preferably 0.01 to 20% by mass, more preferably 1 to 10% by mass, relative to the total mass of the resin composition forming the resin layer 3. If the content of the photopolymerizable compound (C) is above the lower limit mentioned above, the transparency of the resin layer 3 can be further improved. If the content of the photopolymerizable compound (C) is below the upper limit mentioned above, the processability of the resin composition forming the resin layer 3 can be further improved.

[0050] In the resin composition of this embodiment, the mass ratio (hereinafter also referred to as "A / C ratio") expressed as (content of silicone resin (A)) / (content of photopolymerizable compound (C)) is preferably 1 to 8000, more preferably 1 to 1000, further preferably 5 to 500, and particularly preferably 10 to 100. If the A / C ratio is above the lower limit mentioned above, the heat resistance and yellowing resistance of the resin layer 3 can be further improved. If the A / C ratio is below the upper limit mentioned above, the transparency of the resin layer 3 can be further improved.

[0051] Examples of organic solvents (D) include ethers, ketones, esters, and celux esters. Examples of ethers include dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxane, 1,3,5-trioxane, tetrahydrofuran, anisole, or phenethyl ether. Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, or ethylcyclohexanone. Examples of esters include ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, n-pentyl acetate, or γ-butyrolactone. Examples of celux esters include methyl celux, celux (ethyl celux), butyl celux, or celux acetate. Organic solvent (D) can be used alone or in combination with two or more.

[0052] The content of organic solvent (D) is relative to the total mass of the resin composition forming resin layer 3, and is preferably 20 to 80% by mass, more preferably 40 to 60% by mass. If the content of organic solvent (D) is within the above range, the dispersibility of the phosphor described later is improved, and the light-emitting characteristics of the substrate 10 for the display device can be further improved.

[0053] The resin composition of this embodiment may contain other components besides (A) to (D) mentioned above. Examples of such other components include additives such as phosphors and ultraviolet absorbers, which will be described later. If the resin composition contains other components, the content of the other components is relative to the total mass of the resin composition, and is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass.

[0054] By curing the resin composition of this embodiment, resin layer 3 can be obtained. The thickness T3 of the resin layer 3 is preferably 1~50μm, more preferably 2~40μm, and even more preferably 3~30μm. If the thickness T3 of the resin layer 3 is above or above the lower limit mentioned above, the light-emitting characteristics of the substrate 10 for the display device can be further improved. If the thickness T3 of the resin layer 3 is below or below the upper limit mentioned above, the production efficiency of the substrate 10 for the display device can be further improved. The thickness T3 of the resin layer 3 can be determined, for example, by observing a cross-section of the substrate 10 for display devices in the thickness direction using a microscope. The thickness T3 of the resin layer 3 can be adjusted according to the amount of resin components used and the height H4 of the partition wall 4 described later.

[0055] The transmittance of resin layer 3 at 385 nm is preferably 96.0% or higher, more preferably 97.0% or higher, and even more preferably 98.0% or higher. If the transmittance of resin layer 3 at 385 nm is above the lower limit mentioned above, the transparency of resin layer 3 can be further improved. The higher the upper limit of the transmittance of resin layer 3 at 385 nm, the better; ideally, it is 100%. The transmittance of resin layer 3 at 385 nm can be measured, for example, using a UV-Vis spectrophotometer. Furthermore, the 385nm transmittance of the resin layer 3 refers to the transmittance measured within 24 hours after the substrate 10 for the display device is manufactured, or more specifically, after being stored at room temperature (e.g., 5~30℃) and humidity 20~70%RH for 24 hours (hereinafter also referred to as "initial transmittance"). The initial transmittance of the resin layer 3 can be adjusted, for example, by the type and amount of silicone resin (A) contained in the resin composition, the type and amount of photopolymerizable compound (C), and their combination.

[0056] The transmittance at 385 nm (hereinafter also referred to as "transmittance after heating") after heating resin layer 3 in air at 150°C for 500 hours is preferably 95.0% or higher, more preferably 95.5% or higher, and even more preferably 96.0% or higher. If the transmittance after heating is above the lower limit mentioned above, the resin layer 3 exhibits superior heat resistance and resistance to yellowing. The higher the upper limit of the transmittance after heating, the better; ideally, it is 100%. The transmittance after heating can be measured, for example, by placing the display device substrate 10 into an oven set to 150°C and removing it from the oven after 500 hours, using a UV-Vis spectrophotometer. The transmittance after heating can be adjusted, for example, by the type and amount of silicone resin (A), the amount of repeating units represented by formula (ia) in silicone resin (A).

[0057] The difference between the initial transmittance and the transmittance after heating of resin layer 3 (hereinafter also referred to as "transmittance difference") is preferably 2.0% or less, more preferably 1.0% or less, and even more preferably 0.5% or less. If the transmittance difference is below the above upper limit, the resin layer 3 exhibits superior heat resistance and resistance to yellowing. The smaller the lower limit of the transmittance difference, the better; ideally, it is 0.0%. The transmittance difference can be calculated using the following equation (I). Transmittance difference (%) = Initial transmittance (%) - Transmittance after heating (%) ... (I)

[0058] The transmittance retention rate of resin layer 3, expressed by formula (II) below (hereinafter also referred to as "transmittance retention rate"), is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. If the transmittance retention rate is above the lower limit value mentioned above, resin layer 3 can maintain high transparency, and its heat resistance and yellowing resistance are even better. The higher the upper limit value of the transmittance retention rate, the better, ideally 100%. Transmittance retention rate (%) = {(Transmittance after heating (%)) / (Initial transmittance (%))} × 100…(II)

[0059] The content of silicone resin (A) in resin layer 3 is preferably 20-80% by mass, more preferably 30-70% by mass, and even more preferably 40-60% by mass, relative to the total mass of resin layer 3. If the content of silicone resin (A) in resin layer 3 is above or above the lower limit mentioned above, the heat resistance and yellowing resistance of resin layer 3 can be further improved. If the content of silicone resin (A) in resin layer 3 is below or above the upper limit mentioned above, the transparency of resin layer 3 can be further improved.

[0060] Two or more resin layers 3 may be partially or entirely phosphor layers containing phosphors. If 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 emitting the three primary colors of light. 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.

[0061] Examples of phosphors include Eu²⁺ activated phosphors, which have europium (Eu²⁺) in their luminescent centers, and Mn²⁺ activated phosphors, which have manganese (Mn²⁺) in their luminescent centers. When a phosphor is illuminated with excitation light, the luminescent ions (e.g., Eu²⁺) absorb the excitation light, and electrons in the ground state are excited to an excited state. When these excited electrons return to the ground state, the energy difference is emitted as fluorescence. For Eu²⁺, the transition between emission and absorption is allowed, resulting in a high probability of transition. On the other hand, for Mn²⁺, the transition between emission and absorption is forbidden. Therefore, the transition probability is low, but emission with a narrow spectral width can be obtained, improving color reproducibility.

[0062] Examples of Eu²⁺-activated phosphors include CASN phosphors. Examples of Mn²⁺-activated phosphors include KSF phosphors. The wavelength width of the CASN phosphor system is wider than that of the KSF phosphor. However, the time required for the luminous intensity of the secondary light from the CASN phosphor to reach 1 / e (where e is the base of the natural logarithm) when the primary light from the LED element is extinguished (hereinafter also referred to as "afterglow time") is about 1~10μs. The afterglow time of the KSF phosphor system is approximately 10ms, which is 100 to 1000 times longer than that of the CASN phosphor. Therefore, in image display devices where LEDs are turned on or off, even at the moment the light from the LED element is turned off, a residual red light remains in the KSF phosphor, which is excited and emits light by the light from that LED element. This residual red light from the KSF phosphor causes problems such as the displayed image appearing colored, and in 3D displays, crosstalk, a phenomenon where left and right images are mixed. This crosstalk phenomenon is particularly noticeable in images where telep characters flow across the screen, where a portion of the superimposed image appears red. Therefore, Eu²⁺ activated phosphors are preferred as phosphors. Using only Eu²⁺ activated phosphors with short afterglow times as the phosphor can improve the performance of image display devices. However, the Eu²⁺ activated phosphor system has a wide wavelength range at its peak wavelength, resulting in poorer color reproduction compared to Mn²⁺ activated phosphors. But this color reproduction can be compensated for by incorporating a color filter layer on the phosphor layer.

[0063] The dispersed particle size of the phosphor is preferably 0.5~30μm, more preferably 1~20μm. If the dispersed particle size of the phosphor is above or above the lower limit mentioned above, the heat resistance of the phosphor layer can be further improved. If the dispersed particle size of the phosphor is below or below the upper limit mentioned above, the color reproduction of the phosphor layer can be further improved. In this specification, the term "dispersed particle size" of the phosphor refers to the average particle size after the phosphor is dispersed in the resin composition, meaning the particle size at 50% of the cumulative value in the particle size distribution determined by the photon correlation method.

[0064] The phosphor content, relative to the total mass of the phosphor layer, is preferably 10-70% by mass, more preferably 20-60% by mass, and even more preferably 30-50% by mass. If the phosphor content is above the lower limit mentioned above, the luminescence intensity of the phosphor layer can be further improved. If the phosphor content is below the upper limit mentioned above, the transmittance of the phosphor layer can be further improved.

[0065] The phosphor layer can further contain quantum dots. Quantum dots are nanoscale semiconductor microparticles that exhibit quantum confinement effects. The inclusion of quantum dots in the phosphor layer further enhances its color reproducibility. The quantum dot content, relative to the total mass of the phosphor layer, is preferably 10-70% by mass, more preferably 20-50% by mass. If the quantum dot content is above the lower limit mentioned above, the color reproducibility of the phosphor layer can be further improved. If the quantum dot content is below the upper limit mentioned above, the heat resistance of the phosphor layer can be further improved.

[0066] "partition" The partition 4 divides the substrate 1 into a plurality of resin layers 3 along its surface. The substrate 10 for the display device, having the partition 4, has the function of preventing light mixing between adjacent resin layers 3. The shape of the partition 4 as viewed from above is not particularly limited, and can be, for example, a square, a rectangle, a rhombus, a parallelogram, or a triangle. As the partition wall 4, the surface of the wall formed by the light resist is covered with a thin film of a metal with high reflectivity, such as aluminum or silver. The partition wall 4 is preferably light reflective, but it may also be light scattering.

[0067] The height H4 of the partition wall 4 is preferably 1~50μm, more preferably 2~40μm, and even more preferably 3~30μm. If the height H4 of the partition wall 4 is above or above the lower limit mentioned above, the light-emitting characteristics of the substrate 10 for the display device can be further improved. If the height H4 of the partition wall 4 is below or above the upper limit mentioned above, the light emitted from the light-emitting element 2 can be extracted more efficiently. Here, the height H4 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 arrangement direction of the light-emitting element 2 and the resin layer 3). The height H4 of the partition wall 4 can be determined, for example, by observing a cross-section of the substrate 10 for display devices in the thickness direction using a microscope. The height H4 of partition wall 4 can be adjusted by the shape of the pattern formed when partition wall 4 is created.

[0068] The thickness T4 of the partition wall 4 is preferably 0.5~30μm, more preferably 1~25μm, and even more preferably 2~20μm. If the thickness T4 of the partition wall 4 is above the lower limit mentioned above, the mixing of light between adjacent resin layers 3 can be prevented more reliably. If the thickness T4 of the partition wall 4 is below the upper limit mentioned above, the light-emitting area of ​​the resin layer 3 can be increased. Here, the thickness T4 of the partition wall 4 refers to the length of the partition wall 4 in the horizontal direction (the arrangement direction of the resin layer 3) relative to the surface of the substrate 1. The thickness T4 of the partition wall 4 can be determined, for example, by observing a cross-section of the substrate 10 for display devices in the thickness direction using a microscope. The thickness T4 of partition 4 can be adjusted by the shape of the pattern formed when partition 4 is formed.

[0069] The reflectivity per 10 μm thickness of the partition wall 4 (hereinafter also referred to as "reflectivity of the partition wall 4") is preferably 60-90%, more preferably 65-85%, and even more preferably 70-80%. If the reflectivity of the partition wall 4 is above the lower limit mentioned above, the brightness of the resin layer 3 can be further improved by utilizing the reflection of light from the side of the partition wall 4. If the reflectivity of the partition wall 4 is below the upper limit mentioned above, light scattering can be suppressed, and the light-emitting characteristics of the substrate 10 for the display device can be further improved. In this specification, the reflectance of the partition wall 4 refers to the reflectance measured using a spectrophotometer (SolidSpec-3700iDUV, manufactured by Shimadzu Corporation) when light of wavelength 550nm is incident at an angle of 45° onto a surface perpendicular to the thickness direction of the partition wall 4 with a thickness of 10μm. The reflectivity of partition wall 4 can be adjusted by the type and thickness of the thin film on the surface of partition wall 4.

[0070] [Manufacturing method of substrate for display device] The manufacturing method of the display device substrate 10 in this embodiment is not particularly limited if the above-described structure can be formed. For example, the component that forms the partition wall 4 is coated onto the surface of the substrate 1 to form a pattern, thereby obtaining a substrate with partition walls. Light-emitting elements 2 are formed or disposed on the surface of the substrate 1 in each region S surrounded by the partition walls 4 of the obtained substrate with partition walls. Next, the resin composition forming the resin layer 3 is filled into each region S containing the light-emitting element 2, and the resin composition is hardened by irradiation with ultraviolet light, etc., to obtain a display device substrate 10 in which the resin layer 3 is formed on the surface of the light-emitting element 2. Furthermore, a portion (one) or all of two or more resin layers 3 may be a phosphor layer containing phosphors.

[0071] The component for forming the partition wall 4 can be the same as the resin component for forming the resin layer 3 described above. The following describes in more detail the manufacturing method of a display device substrate 10 in which the resin composition forming the resin layer 3 is used as the component for forming the partition 4.

[0072] The resin composition is coated onto the substrate 1. Examples of coating methods include spin coating, slot coating, screen printing, inkjet coating, and bar coating. The substrate coated with the resin composition is dried (pre-baked). Examples of pre-baking methods include vacuum drying and heat drying. Examples of heating devices include heating plates and ovens. The preferred heating temperature during pre-baking is 60~150℃, more preferably 80~120℃. If the heating temperature during pre-baking is within the above range, a stable coating film can be formed. The heating time during pre-baking is preferably between 30 seconds and 3 minutes. If the heating time during pre-baking is within the above range, a stable coating film can be formed. The thickness of the pre-baked coating is preferably 1~50μm, more preferably 2~40μm, and even more preferably 3~30μm.

[0073] A substrate with a patterned coating is obtained by exposing and developing the coating on a pre-baked substrate. Exposure can be performed using a mask or without one. The exposure machine is not particularly limited to devices equipped with high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, halogen lamps, etc., that irradiate ultraviolet or visible light in the range of 250-500 nm. Examples of exposure machines include steppers, mirror projection mask alignment machines (MPA), and parallel light mask alignment machines (PLA). The optimal exposure intensity is around 10~4000 J / m² (converted from exposure at a wavelength of 365nm). Examples of light sources for exposure include ultraviolet light such as i-line, g-line, and h-line, KrF (wavelength 248nm) laser, and ArF (wavelength 193nm) laser.

[0074] The exposed coating can be further heated. For example, heating it at 50-150°C for 10-60 minutes can further improve the strength of the coating.

[0075] Methods for developing exposed coatings include, for example, showering, dipping, and puddle. The preferred contact time between the developer and the coating is 5 seconds to 10 minutes. Examples of developing solutions include aqueous solutions of inorganic bases, aqueous solutions of amines, and aqueous solutions of quaternary ammonium salts. Examples of inorganic bases include alkali metal hydroxides, carbonates, phosphates, silicates, and borates. Examples of amines include 2-diethylaminoethanol, monoethanolamine, and diethanolamine. Examples of quaternary ammonium salts include tetramethylammonium hydroxide and choline.

[0076] It is preferable to wash the coating with water after development. Then, it can be dried and baked at 50~140℃.

[0077] A patterned substrate obtained by developing is heated to obtain a patterned substrate with a hardened coating. Here, the so-called patterned processing substrate refers to a substrate with a patterned hardened film (wall). Examples of heating devices include heating plates and ovens. The heating temperature is preferably 120~250℃, more preferably 200~250℃. If the heating temperature is above the lower limit of the above values, the hardened film can be sufficiently hardened. If the heating temperature is below the upper limit of the above values, the thermal degradation of the hardened film can be suppressed. The heating time is preferably 15 minutes to 2 hours, and more preferably 20 minutes to 1 hour. If the heating time is above the lower limit, the curing film can be sufficiently cured. If the heating time is below the upper limit, the productivity of the substrate 10 for the display device can be further improved.

[0078] On the patterned surface of the resulting patterned substrate, a metal thin film of aluminum, nickel, or the like is formed to a predetermined thickness. The metal thin film can be formed by vapor deposition or by electroless plating. During the formation of the metal thin film, the portion that becomes a light channel is masked. The thickness of the metal thin film is preferably 0.01~1μm, more preferably 0.1~0.5μm. If the thickness of the metal thin film is above the lower limit mentioned above, the reflectivity of the partition 4 can be further improved. If the thickness of the metal thin film is below the upper limit mentioned above, the productivity of the substrate 10 for the display device can be further improved. The thickness of the metal thin film can be determined, for example, by observing a cross-section of the substrate 10 for display devices in the thickness direction using a microscope.

[0079] By forming a metal thin film, a partition wall 4 can be obtained in which the surface of the wall is covered by the metal thin film. On the surface of the substrate 1 of the substrate with the partition wall attached, in each region S surrounded by the partition wall 4, light-emitting elements 2 are formed or disposed. Next, the resin composition forming the resin layer 3 is filled into each region S containing the light-emitting element 2. Similar to the formation of a hardened film (wall) described above, a display device substrate 10 in which a resin layer 3 is formed in each region S containing the light-emitting element 2 can be obtained by exposing and heating a substrate filled with a resin composition. The exposure machine, exposure intensity, and exposure light source are the same as those used in the above-mentioned device for exposing the coating. The temperature at which the exposed resin composition is heated (hereinafter also referred to as the "resin composition heating temperature") is preferably 120~250°C, more preferably 150~230°C. If the resin composition heating temperature is above the lower limit of the above, the resin composition can be sufficiently cured. If the resin composition heating temperature is below the upper limit of the above, the thermal degradation of the resin composition can be suppressed. The heating time (hereinafter also referred to as "resin composition heating time") when heating the exposed resin composition is preferably 15 minutes to 2 hours, and more preferably 20 minutes to 1 hour. If the heating time of the resin composition is above the lower limit mentioned above, the resin composition can be sufficiently cured. If the heating time of the resin composition is below the upper limit mentioned above, the productivity of the substrate 10 for the display device can be further improved.

[0080] Furthermore, by adding phosphor to the resin composition forming the resin layer 3, and filling this composition (hereinafter also referred to as "resin composition containing phosphor") into each region S containing the light-emitting element 2, and then exposing and heating it, a substrate for a display device in which a phosphor layer is formed in each region S containing the light-emitting element 2 can be obtained.

[0081] The resin composition containing phosphors is preferably a resin (dispersion) that disperses the phosphors. Examples of resins used as dispersions include silicone resins, epoxy resins, phenolic resins, polycarbonate resins, acrylic resins, polynorbornene resins, modified resins of these types, and hybrid resins. These resins are preferably liquid dispersions formed using monomers or organic solvents constituting the aforementioned resins. Because they are liquid dispersions, the resin composition containing phosphors can be coated and filled into each region S containing the light-emitting element 2. Examples of apparatus for coating the resin composition containing phosphors include spin coaters, slot coaters, screen coaters, and inkjet printers.

[0082] The content of the dispersion, relative to the total mass of the resin composition containing the phosphor, is preferably 20-80% by mass, more preferably 30-70% by mass, and even more preferably 40-60% by mass. If the content of the dispersion is above the lower limit mentioned above, the phosphor can be dispersed better. If the content of the dispersion is below the upper limit mentioned above, the luminescence intensity of the phosphor layer can be further improved.

[0083] The phosphor content, relative to the total mass of the resin composition containing the phosphor, is preferably 5-50% by mass, more preferably 10-45% by mass, and even more preferably 15-30% by mass. If the phosphor content is above the lower limit mentioned above, the luminescence intensity of the phosphor layer can be further improved. If the phosphor content is below the upper limit mentioned above, the decrease in transmittance and brightness of the phosphor layer can be suppressed.

[0084] The phosphor content is preferably 5 to 50 parts by mass relative to 100 parts by mass of the resin (base resin) that forms the dispersion, more preferably 10 to 45 parts by mass, and even more preferably 20 to 40 parts by mass. If the phosphor content is above the lower limit mentioned above, the luminescence intensity of the phosphor layer can be further improved. If the phosphor content is below the above-mentioned upper limit, the decrease in transmittance and brightness of the phosphor layer can be suppressed.

[0085] The exposure machine, exposure intensity, and exposure light source used when exposing the resin composition containing phosphors are the same as those used when exposing the coating film as described above. The temperature at which the exposed resin composition containing phosphors is heated (hereinafter also referred to as the "heating temperature of the resin composition containing phosphors") is preferably 120~250°C, more preferably 180~230°C. If the heating temperature of the resin composition containing phosphors is above or above the above lower limit, the resin composition containing phosphors can be sufficiently cured. If the heating temperature of the resin composition containing phosphors is below the above upper limit, the thermal degradation of the resin composition containing phosphors can be suppressed. The heating time (hereinafter also referred to as "heating time of the phosphor-containing resin composition") when heating the exposed resin composition containing phosphor is preferably 15 minutes to 2 hours, and more preferably 30 minutes to 1 hour. If the heating time of the phosphor-containing resin composition is at or above the lower limit mentioned above, the phosphor-containing resin composition can be sufficiently cured. If the heating time of the phosphor-containing resin composition is at or below the upper limit mentioned above, the productivity of the substrate for the display device can be further improved.

[0086] [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, for example, televisions, monitors, mobile phones, portable game consoles, portable information terminals, personal computers, e-books, cameras, digital cameras, head-mounted displays, navigation systems, audio playback devices (car stereos, digital audio players, etc.), photocopiers, fax machines, printers, multifunction printers, vending machines, automatic teller machines (ATMs), personal authentication machines, optical communication devices, IC cards, etc. These image display devices can be used in a variety of applications. For example, two or more image display devices can be freely combined. In addition, antennas can be added to electronic devices equipped with image display devices to enable communication, contactless power receiving, and power supply.

[0087] Hereinafter, an image display device according to one embodiment of the present invention will be described in detail based on FIG2. As shown in Figure 2, the image display device 100 includes: a substrate 1, a light-emitting element 2, a resin layer 3, a partition 4, a transparent resin layer 5, a color filter layer 7, and a substrate 8. Specifically, the image display device 100 has the following structure: it includes a display device substrate 10, and the transparent resin layer 5, the color filter layer 7, and the substrate 8 are sequentially deposited on the light-emitting surfaces of the resin layer 3 and the partition 4 of the display device substrate 10. The color filter layer 7 includes a color filter 6. In this specification, "image display device" may refer to only one image display device 100 (also called "unit pixel"), or it may refer to a device in which two or more unit pixels are arranged in a horizontal direction to form a matrix.

[0088] Transparent resin layer The transparent resin layer 5 is located on the light-emitting surface of the substrate 10 for the display device. The transparent resin layer 5 is not particularly limited to any transparent layer that can bond the substrate 10 for the display device and the color filter layer 7. Examples of resins that form the transparent resin layer 5 include epoxy resin, phenolic resin, polycarbonate resin, acrylic resin, polynorbornene resin, modified resins of the same kind, and mixed resins of the same kind. Silicone resin (A) described above may also be used as the resin for forming the transparent resin layer 5. These resins can be formed into a liquid dispersion by using monomers or organic solvents. After the liquid resin is formed, the dispersion is coated and hardened using a device such as a rotary coater, slot coater, screen coater, or inkjet printer to form a transparent resin layer 5.

[0089] The thickness T5 of the transparent resin layer 5 is preferably 0.1~5μm, more preferably 0.5~3μm, and even more preferably 1~2μm. If the thickness T5 of the transparent resin layer 5 is above or above the aforementioned lower limit, the resin layer 3 can be adequately sealed. If the thickness T5 of the transparent resin layer 5 is below or above the aforementioned upper limit, the luminous intensity of the image display device 100 can be further improved. 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 cut in the thickness direction using a microscope.

[0090] Color Filter Layer The color filter layer 7 has a color filter 6. The color filter 6 controls the wavelength range of light emitted from the resin layer 3 toward the substrate 8. The color filter 6 is composed of a color filter 6R, a color filter 6G, and a color filter 6B. The 6R series color filter controls the transmitted light to be red. The 6G series color filter controls the transmitted light to be green. The 6B series color filter controls the transmitted light to be blue. Color filter 6R, color filter 6G, and color filter 6B can be separated from each other or adjacent to each other.

[0091] The thickness T7 of the color filter layer 7 is preferably 0.1~5μm, more preferably 0.5~3μm, and even more preferably 0.7~1.5μm. If the thickness T7 of the color filter layer 7 is above or below the aforementioned lower limit, the wavelength range of the transmitted light can be controlled more reliably. If the thickness T7 of the color filter layer 7 is below or below the aforementioned upper limit, the transmittance of the transmitted light can be further improved. 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 cut in the thickness direction using a microscope.

[0092] As a color filter 6, it can use any color filter with any transmittance used in general image display devices. For example, as a color filter 6R, it is preferable that the transmittance of light with wavelengths of 380nm to 580nm is less than 5%. As a color filter, 6G preferably has a transmittance of less than 5% for light with wavelengths between 380nm and 480nm. As a color filter 6B, it is preferable that the transmittance of light with wavelengths above 480nm and below 780nm is less than 5%.

[0093] Color filter 6 is formed by dispersing organic pigments in a transparent resin such as acrylic resin. Examples of red organic pigments suitable for use in color filter 6R include CI pigments 7, 14, 41, 48:2, 48:3, 48:4, 81:1, 81:2, 81:3, 81:4, 146, 168, 177, 178, 179, 184, 185, 187, 200, 202, 208, 210, 246, 254, 255, 264, 270, 272, and 279. In addition to red pigments, yellow and orange pigments can also be used in color filter 6R.

[0094] For example, examples of organic pigments suitable for use as yellow in color filter 6 include CI 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, and 11. 0, 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.

[0095] Examples of green organic pigments suitable for use in color filter 6G include CI pigments green 7, 10, 36, and 37. Furthermore, zinc halide phthalocyanine green pigments and aluminum halide phthalocyanine green pigments can also be suitably used in color filter 6G. In the 6G color filter, in addition to the green pigment, the aforementioned yellow pigment can also be used.

[0096] Examples of blue organic pigments suitable for use in color filter 6B include CI Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 60, and 64. In color filter 6B, in addition to blue pigment, purple pigment can also be used. Examples of purple pigments include CI pigments 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, and 50.

[0097] These organic pigments can be dispersed in transparent resins together with organic solvents and dispersants for use. The transparent resin is preferably a transparent resin with a transmittance of more than 90% in the visible light region, and more preferably an alkali-soluble photosensitive resin containing resin precursors. When manufacturing the color filter 6, organic pigments can be contained in the range of 15% to 60% by mass relative to the transparent resin.

[0098] Examples of photosensitive resins suitable for color filter 6 include (meth)acrylic acid compounds and cinnamic acid that react with reactive substituents such as isocyanate groups, aldehyde groups, and epoxy groups to react with linear polymers having reactive substituents such as hydroxyl groups, carboxyl groups, and amine groups, and then introduce photocrosslinking groups such as (meth)acrylic acid groups and styrene groups into the aforementioned linear polymers.

[0099] Examples of monomers and oligomers suitable as precursors to transparent resins for color filters 6 include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, cyclohexyl (meth)acrylate, polyethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tricyclodecyl (meth)acrylate, melamine (meth)acrylate, epoxy (meth)acrylate, and various acrylates such as methacrylates, (meth)acrylic acid, styrene, vinyl acetate, (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, and acrylonitrile. These can be used alone or in mixtures of two or more. In cases where a transparent resin containing dispersed organic pigments is hardened by irradiation with ultraviolet light, such as light with a wavelength of 365 nm, a photopolymerization initiator is further added.

[0100] The color filter layer 7, which is separate from the color filter 6, can also be formed from the aforementioned transparent resin.

[0101] 《Substrate》 The substrate 8 is located on the outermost layer of the light-emitting surface of the image display device 100. Examples of substrates 8 include glass plates, resin plates, and resin films, which are the same as those used for substrate 1. The type of substrate 8 may be the same as or different from that of substrate 1. The thickness T 8 of substrate 8 may be the same as the thickness T 1 of substrate 1. The thickness T 8 of substrate 8 may be the same as or different from the thickness T 1 of substrate 1.

[0102] [Manufacturing Method of Image Display Device] The image display device 100 is not particularly limited if the above-described structure can be formed. For example, the color filter layer 7 is coated with a composition onto the surface of the substrate 8 and then hardened to obtain a substrate with a color filter layer. Next, the transparent resin layer composition forming the transparent resin layer 5 is coated on the light-emitting surface of the display device substrate 10, and the area of ​​the color filter layer side of the substrate with the color filter layer is applied to the transparent resin layer composition. The transparent resin layer composition is hardened by irradiation with ultraviolet light, etc., to obtain an image display device 100 in which the substrate with the color filter layer is deposited on the light-emitting surface of the display device substrate 10 through the transparent resin layer 5.

[0103] Furthermore, part or all of the resin layer 3 may be a phosphor layer containing phosphors. For example, the resin layer facing the color filter 6R can contain phosphors to form a phosphor layer 9R. The resin layer facing the color filter 6G can contain phosphors to form a phosphor layer 9G. By making the resin layer 3 into a phosphor layer 9, the light-emitting characteristics of the image display device 100 can be further improved.

[0104] The substrate for the display device according to this embodiment has high transparency and superior heat resistance and yellowing resistance because a silicone resin with a specific structure is used in the resin layer.

[0105] The various embodiments of the present invention have been described in detail above with reference to the drawings. However, the specific configuration is not limited to these embodiments and includes changes and combinations of configurations that do not exceed the scope of the present invention. For example, the substrate for the display device in this embodiment has one unit pixel, but the number of unit pixels may also be two or more. For example, the substrate for the display device in this embodiment does not have a color filter layer, but the substrate for the display device may also have a color filter layer. For example, in the image display device of this embodiment, the number of unit pixels is 1, but the number of unit pixels may also be 2 or more. For example, the image display device of this embodiment has a phosphor layer, but the image display device may also not have a phosphor layer. [Example]

[0106] The present invention will be further described in detail below using examples, but the present invention is not limited to these examples.

[0107] Blue LEDs with a peak wavelength of 385nm are used as the light-emitting element. Eu 2+ activated CASN phosphor was used as the phosphor (red). Eu²⁺-activated (Ba, Sr)GaS phosphors were used as the phosphors (green). Silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd.) is used as the base material for the resin composition that forms the resin layer, and phosphors are dispersed to produce a resin composition containing phosphors. In a comparative example, acrylic resin (manufactured by Sumitomo Chemical Co., Ltd.) is used as the base material for the resin composition.

[0108] Using a spin coater (Mikasa Corporation), the resin composition was coated onto a 10cm square alkali-free glass substrate to a cured film thickness of 20μm. A pre-baked film was then formed by pre-baking at 100°C for 3 minutes using a heated plate (ASONE Corporation). The pre-baked film was then exposed using a parallel light mask alignment machine (Topcon Corporation) with an ultra-high pressure mercury lamp as the light source, without passing through the mask, at an exposure dose of 200mJ / cm² (ghi line) and an exposure gap of 100μm. Afterwards, an automatic developing device (Mikasa Corporation's "AD-1200") was used for spray development with a 0.5% (w / w) sodium hydroxide aqueous solution for 30 seconds, followed by washing with water for 15 seconds. The washed substrate was then dried at 230°C for 30 minutes to obtain the resin layer.

[0109] [Example 1, Comparative Example 1] The transmittance (initial stage) at 385 nm was measured using a UV-Vis spectrophotometer (Hitachi HighTech Co., Ltd.) on the resin layer obtained above. Next, the substrate with the resin layer formed was placed in an oven (manufactured by Yamato Scientific) and heated at 150°C for 500 hours. After the substrate was left to stand at room temperature (15~25°C) overnight, the transmittance at 385 nm and the yellowness (after heating) were measured using the aforementioned UV-Vis spectrophotometer. The transmittance difference and transmittance retention rate were calculated from the obtained transmittance values, and the results are presented in Table 1.

[0110] [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 base resin type Silicone resin Silicone resin Silicone resin Silicone resin Silicone resin acrylic acid resin acrylic acid resin acrylic acid resin acrylic acid resin acrylic acid resin content (parts by weight) 100 100 100 100 100 100 100 100 100 100 Fluorescent type - red red green green - red red green green content (parts by weight) 0 30 40 30 40 0 30 40 30 40 Dispersed particle size (μm) - 3.7 4.6 - 3.7 4.6 Resin layer thickness (μm) 30 20 20 20 20 30 20 20 20 20 transmittance (%) Early stage 96.1 40.2 36.5 50.7 41.9 94.1 35.5 31.6 47.3 41.2 After heating 95.5 39.9 36.2 50.4 41.6 87.3 31.5 28.1 41.2 35.7 poor transmittance 0.6 0.3 0.3 0.3 0.3 6.8 4.0 3.5 6.1 5.5 Retention rate (%) 99.4 99.3 99.2 99.4 99.3 92.8 88.7 88.9 87.1 86.7 glowing characteristic (450nm) PLQY - 0.983 0.968 0.881 0.795 - 0.939 0.942 0.863 0.862 Abs - 0.563 0.558 0.522 0.515 - 0.558 0.567 0.46 0.451 λmax(nm) - 634.13 631.16 528.93 531.93 - 634.13 631.16 530.43 529.68 Crest intensity (au) - 902.99 894.08 1503.17 1368.03 - 848.92 873.57 1327.71 1296.01 Full width at half maximum (nm) - 83.79 82.9 50.93 49.93 - 84.28 83.63 50.28 50.58 Optical Concentration - 0.3634 0.3596 0.3274 0.3195 - 0.3587 0.3647 0.2682 0.2619 Light characteristic (385nm) PLQY - 1.065 1.043 0.946 0.858 - 0.995 0.997 0.870 0.877 Abs - 0.551 0.538 0.525 0.551 - 0.526 0.571 0.487 0.513 λmax(nm) - 633.39 633.39 528.93 530.43 - 633.39 629.67 529.68 528.18 Crest intensity (au) - 1205.92 1171.68 2040.09 1978.92 - 1087.31 1154.31 1779.49 February 1886 Half-height width (nm) - 83.94 82.64 51.03 50.04 - 83.72 84.57 50.78 50.65 Optical Concentration - 0.3461 0.3352 0.3234 0.3481 - 0.3243 0.3722 0.2926 0.3143 Bright front Degree measurement Crest intensity (au) - 0.1508 0.1555 0.2703 0.2477 - 0.1418 - 0.2734 - Optical Concentration - 1.39 1.62 1.28 1.59 - 0.99 - 1.37 -

[0111] Furthermore, the transmission spectra (after heating) of Example 1 and Comparative Example 1 are presented in Figure 3. As shown in Figure 3, in the region below approximately 550 nm, the transmittance of Example 1 is higher than that of Comparative Example 1. This means that compared to the resin layer of Comparative Example 1, the resin layer of Example 1 has higher transparency and superior heat resistance and yellowing resistance.

[0112] [Examples 2-3, Comparative Examples 2-3] The phosphor (red) was pulverized and its particle size adjusted, and then dispersed in the resin (base resin) that served as the base material at the proportions shown in Table 1, and a phosphor layer was obtained in the same manner as in Example 1. The dispersed particle size of the phosphor (red) was calculated as the particle size representing 50% of the cumulative value in the particle size distribution determined by photon correlation. For 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 presented in Table 1.

[0113] [Examples 4-5, Comparative Examples 4-5] The phosphor (green) was pulverized and its particle size adjusted, and then dispersed in the resin (base resin) that served as the base material at the proportions shown in Table 1, and a phosphor layer was obtained in the same manner as in Example 1. The dispersed particle size of the phosphor (green) was calculated as the particle size representing 50% of the cumulative value in the particle size distribution determined by photon correlation. For 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 presented in Table 1.

[0114] <Determination of luminescent properties (450nm)> The luminescence properties were measured using an integrating sphere attached to a UV-Vis spectrophotometer (manufactured by Hitachi HighTech). Measurement light at a wavelength of 450 nm, transmitted through the phosphor layers of each example, was irradiated onto the integrating sphere, and the quantum yield (PLQY), absorbance (Abs), peak wavelength (λmax (nm)), peak intensity (au (arbitrary unit)), full width at half maximum (FWHM) (nm), and optical density (OD value) were determined using a detector. The results are presented in Table 1. In this specification, optical density (OD value) means the value expressed by the following formula (III). OD value = -log(IT / IO)...(III) In equation (III), IO represents the incident light intensity (au) for the measured object, and IT represents the transmitted light intensity (au).

[0115] <Determination of luminescent properties (385nm)> The luminescence properties were measured using an integrating sphere attached to a UV-Vis spectrophotometer (manufactured by Hitachi HighTech). Measurement light at a wavelength of 385 nm, transmitted through the phosphor layer of each example, was irradiated onto the integrating sphere, and the quantum yield (PLQY), absorbance (Abs), peak wavelength (λmax (nm)), peak intensity (au), full width at half maximum (FWHM) (nm), and optical density (OD value) were determined using a detector. The results are presented in Table 1.

[0116] <Measurement of Frontal Brightness> As LED elements, a planar light-emitting device (manufactured by MUTOH Holdings) equipped with a blue LED with a peak emission wavelength of 455nm was used as the light source, and the substrate of each example was disposed on the planar light-emitting device with the phosphor layer as the light source side. Current was applied to this planar light-emitting device to illuminate the LED element, and the luminance (unit: cd / m²) based on CIE 1931 specifications was measured using a spectrophotometer (CS-1000, manufactured by Konica Minolta) as the initial luminance. Based on the obtained initial luminance, the peak intensity (au) and optical density (OD value) of the phosphor layer of each example were determined. The results are presented in Table 1.

[0117] Figure 4 shows the transmission spectra of the transmittance of the phosphor layers of Examples 2, Comparative Examples 2, 4, and 4 after heating. As shown in Figure 4, it can be seen that the transmittance at a wavelength of 385 nm is greater in Example 2 compared to Comparative Example 2. Similarly, it can be seen that the transmittance at a wavelength of 385 nm is greater in Example 4 compared to Comparative Example 4.

[0118] Figure 5 shows the excitation and fluorescence spectra of the phosphor (green) used in this embodiment. The vertical axis of the graph in Figure 5 represents the fluorescence intensity (au). As shown in Figure 5, the phosphor (green) used in this embodiment has a peak wavelength (λmax) with a fluorescence peak near a wavelength of 530nm.

[0119] Figure 6 shows the excitation and fluorescence spectra of the phosphor (red) used in this embodiment. The vertical axis of the graph in Figure 6 represents the fluorescence intensity (au). As shown in Figure 6, the phosphor (red) used in this embodiment has a peak wavelength (λmax) with a fluorescence peak near a wavelength of 620nm.

[0120] As shown in Table 1, Example 1, which applies the present invention, has a transmittance of over 95% after heating. Compared with Comparative Example 1, which uses acrylic resin as the base resin, it has high transparency and superior heat resistance and yellowing resistance. It can be seen that Example 2, which applies the present invention, has higher transmittance after heating and better heat resistance and yellowing resistance compared to Comparative Example 2, which uses acrylic resin as the base resin. It can be seen that Example 3, which applies the present invention, has higher transmittance after heating and better heat resistance and yellowing resistance compared with Comparative Example 3, which uses acrylic resin as the base resin. It can be seen that Example 4, which applies the present invention, has higher transmittance after heating and better heat resistance and yellowing resistance compared to Comparative Example 4, which uses acrylic resin as the base resin. It can be seen that Example 5, which applies the present invention, has higher transmittance after heating and better heat resistance and yellowing resistance compared to Comparative Example 5, which uses acrylic resin as the base resin. From the above results, it can be seen that the embodiments 1 to 5 of the present invention, as substrates for display devices, have high transparency and superior heat resistance and yellowing resistance. [Potential for industrial application]

[0121] The display device substrate and image display device according to the present invention have high transparency and superior heat resistance and yellowing resistance.

[0122] 1:Substrate 2: Light-emitting element 3: Resin layer 4: Partition wall 5: Transparent resin layer 6: Color Filter 7: Color Filter Layer 8:Substrate 10: Board for display devices 100: Image display device S: Area

Claims

1. A substrate for a display device comprising a substrate having two or more light-emitting elements that emit light in the near-ultraviolet or blue wavelength band, a partition surrounding each of the light-emitting elements, and a resin layer on the surface of the light-emitting elements, wherein the resin layer is a cured form of a resin composition comprising silicone resin (A), the silicone resin (A) containing 40 to 70 moles of repeating units represented by the following formula (ia) relative to the total number of repeating units constituting the silicone resin (A), and the surface of the partition being coated with a thin film of aluminum or silver. [In formula (ia), R is a hydrogen atom or a hydrocarbon group with 1 to 30 carbon atoms and a valence of 1 to 3. The hydrocarbon group can be aliphatic or aromatic, saturated or unsaturated, and can be linear, branched or cyclic. If the hydrocarbon group has 2 or more carbon atoms, one or more methylene groups in the hydrocarbon group are unsubstituted or substituted by oxygen, imine or carbonyl groups. One or more hydrogen groups in the hydrocarbon group are unsubstituted or substituted by fluorine, hydroxyl or alkoxy groups with 1 to 20 carbon atoms. One or more carbon atoms are unsubstituted or substituted by silicon. If the hydrocarbon group is divalent or trivalent, the hydrocarbon group links the Si contained in the plurality of repeating units to each other.] 2. The substrate for a display device as claimed in claim 1, wherein a portion or all of the resin layer is a phosphor layer further comprising a phosphor.

3. The substrate for a display device as claimed in claim 2, wherein the phosphor has europium at its light-emitting center.

4. The substrate for a display device as claimed in claim 2, wherein the phosphor can be excited by a blue light source with a wavelength of 380 to 480 nm, and the peak wavelength of the fluorescence spectrum is in the range of 400 to 700 nm.

5. The substrate for a display device as claimed in claim 3, wherein the phosphor can be excited by a blue light source with a wavelength of 380 to 480 nm, and the peak wavelength of the fluorescence spectrum is in the range of 400 to 700 nm.

6. The substrate for a display device as claimed in claim 2, wherein the content of the phosphor is 20 to 70% by mass relative to the total mass of the phosphor layer.

7. The substrate for a display device as claimed in claim 2, wherein the phosphor layer further comprises quantum dots.

8. The substrate for a display device as claimed in any one of claims 1 to 7, wherein the thickness of the resin layer is 1 to 50 μm.

9. An image display device comprising a display device substrate as claimed in any one of claims 1 to 8.

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