Sheet for sealing optical semiconductor element

Abstract

To provide a sheet for sealing optical semiconductor elements that is superior in anti-glare property and also superior in color uniformity.SOLUTION: A sheet 1 for sealing optical semiconductor elements is for sealing one or more optical semiconductor elements 6 arranged on a substrate 5. The sheet 1 for sealing optical semiconductor elements comprises a sealing resin layer 2 at least including a curable resin layer (A)21. An uneven surface 4a of a release liner 4 with the uneven surface 4a is stuck on a surface 2b of the sealing resin layer 2 on the opposite side from an optical semiconductor element 6-sealing surface 2a. The curable resin layer (A)21 is in contact with the uneven surface 4a of the release liner 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sheet for encapsulating an optical semiconductor element. More specifically, the present invention relates to a sheet suitable for use in encapsulating an optical semiconductor element. [Background technology]

[0002] Self-emitting display devices such as mini / micro LED display devices (Mini / Micro Light Emitting Diode Displays) are known to have a structure in which multiple LEDs are arranged on a substrate and sealed with a sealing resin. A known method for sealing the multiple LEDs collectively using the sealing resin is to pour liquid resin into the area where the multiple LEDs are arranged, bury the multiple LEDs, and then harden the liquid resin by applying heat or ultraviolet light.

[0003] However, the method of encapsulating optical semiconductor elements such as LEDs using a liquid resin has problems such as poor handling, such as dripping when the liquid resin is applied and adhesion of the liquid resin to unintended areas, etc. In contrast, by using an encapsulating sheet having an encapsulating layer for encapsulating optical semiconductor elements instead of using a liquid resin, it is possible to encapsulate the optical semiconductor elements easily and in a short time using a simple process.

[0004] As such a sealing sheet, for example, Patent Document 1 discloses a pressure-sensitive adhesive sheet which is a laminate of a colored pressure-sensitive adhesive layer and a colorless pressure-sensitive adhesive layer, and the colorless pressure-sensitive adhesive layer is positioned so as to contact an optical semiconductor element. Also, for example, Patent Document 2 discloses a resin sheet which includes a curable resin composition layer and is used for sealing electronic components. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-169262 [Patent Document 2] Japanese Patent Application Publication No. 2019-67852 Summary of the Invention [Problem to be solved by the invention]

[0006] In some cases, a substrate provided with an antiglare layer is used as the sealing sheet in order to provide a function of preventing reflection of external light on a display device. However, a display device using a sealing sheet provided with a substrate having an antiglare layer on its surface has a problem that the color of the display device changes depending on the angle at which the display device is viewed, and the color uniformity of the display device may be impaired.

[0007] The present invention has been devised under these circumstances, and an object of the present invention is to provide an optical semiconductor element encapsulation sheet and an optical semiconductor element encapsulation sheet that have excellent antiglare properties and excellent color uniformity when an optical semiconductor element is encapsulated. Another object of the present invention is to provide an optical semiconductor device that has excellent antiglare properties and excellent color uniformity, and a method for manufacturing the optical semiconductor device. [Means for solving the problem]

[0008] As a result of intensive studies to achieve the above object, the present inventors have found that a specific encapsulating sheet has excellent antiglare properties and excellent color uniformity when encapsulating an optical semiconductor element. The present invention has been completed based on these findings.

[0009] That is, the present invention provides a sheet for encapsulating one or more optical semiconductor elements arranged on a substrate, The sheet includes an encapsulating resin layer including at least a curable resin layer, the uneven surface of a release liner having an uneven surface is attached to a surface of the encapsulating resin layer opposite to the optical semiconductor element encapsulating surface, The curable resin layer is in contact with the uneven surface of the release liner, thereby providing a sheet for encapsulating an optical semiconductor element.

[0010] The arithmetic mean roughness Ra of the uneven surface of the release liner is preferably 0.2 μm or more.

[0011] The curable resin layer preferably has thermosetting properties.

[0012] The present invention also provides a sheet for encapsulating one or more optical semiconductor elements arranged on a substrate, comprising: the sheet includes an encapsulating resin layer including at least a cured resin layer that provides a surface opposite to the optical semiconductor element encapsulating surface, The optical semiconductor element encapsulating sheet is provided, wherein the surface of the opposite side of the cured resin layer is an uneven surface.

[0013] The arithmetic mean roughness Ra of the uneven surface of the cured resin layer is preferably 0.2 μm or more.

[0014] The present invention also provides an optical semiconductor device comprising: a substrate; an optical semiconductor element disposed on the substrate; and the optical semiconductor element encapsulating sheet that encapsulates the optical semiconductor element.

[0015] Further, the present invention provides a method for manufacturing a semiconductor device, comprising the steps of: laminating the optical semiconductor element encapsulation sheet to the optical semiconductor element provided on the substrate, and encapsulating the optical semiconductor element with the encapsulating resin layer; a step of curing the curable resin layer in a laminate obtained through the encapsulation step, the laminate including the substrate, an optical semiconductor element disposed on the substrate, and the optical semiconductor element encapsulation sheet that encapsulates the optical semiconductor element, to form a cured resin layer; and The method for manufacturing an optical semiconductor device further comprises the step of peeling off the release liner attached to the cured resin layer to transfer the irregular surface to the cured resin layer. [Effects of the Invention]

[0016] The optical semiconductor element encapsulation sheet of the present invention has excellent antiglare properties and excellent color uniformity when encapsulating an optical semiconductor element, thereby improving the appearance of an optical semiconductor device using the optical semiconductor element encapsulation sheet. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view of a sheet for encapsulating an optical semiconductor element according to one embodiment of the present invention. [Figure 2] 2 is a partial cross-sectional view showing one embodiment of a state in which an optical semiconductor element is encapsulated using the optical semiconductor element encapsulation sheet shown in FIG. 1. FIG. [Figure 3] 2 is a partial cross-sectional view showing one embodiment of an optical semiconductor device using the optical semiconductor element encapsulation sheet shown in FIG. 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] [Optical semiconductor element encapsulation sheet] The optical semiconductor element encapsulation sheet of the present invention includes at least an encapsulating resin layer including a curable resin layer. In this specification, the optical semiconductor element encapsulation sheet refers to a sheet for encapsulating one or more optical semiconductor elements arranged on a substrate with the encapsulating resin layer. In this specification, "encapsulating an optical semiconductor element" refers to embedding at least a portion of the optical semiconductor element in the encapsulating resin layer or covering the optical semiconductor element with the encapsulating resin layer. The encapsulating resin layer has flexibility that allows it to embed at least a portion of the optical semiconductor element or to cover the optical semiconductor element with the encapsulating resin layer.

[0019] <Sealing resin layer> The encapsulating resin layer has a surface on the side that encapsulates the optical semiconductor element (sometimes referred to as the "optical semiconductor element encapsulating surface" or "first surface") and a surface on the opposite side to the optical semiconductor element encapsulating surface (sometimes referred to as the "second surface"). The encapsulating resin layer includes at least a curable resin layer that provides the second surface. The curable resin layer that provides the second surface may be referred to as the "curable resin layer (A)."

[0020] The resin layer for sealing may include other layers other than the curable resin layer (A). The other layer is located on the light semiconductor element sealing surface side of the curable resin layer (A). As the other layer, a layer with a lower visible light transmittance than the visible light transmittance of the curable resin layer (A) (low transmittance layer) is preferable. That is, it is preferable that the visible light transmittance T1 of the low transmittance layer and the visible light transmittance T2 of the curable resin layer (A) satisfy T1 < T2. When T1 < T2, that is, when the visible light transmittance of the low transmittance layer is lower than the visible light transmittance of the curable resin layer (A), when the light semiconductor element is sealed, the low transmittance layer prevents reflection by metal wiring or the like on the substrate and prevents color mixing between the arranged light semiconductor elements, which is preferable for improving the contrast. Also, this configuration is such that the curable resin layer (A) having a higher visible light transmittance than the low transmittance layer is located above (the visual recognition side) the light semiconductor element, which is preferable in that the luminous efficiency can be improved to brighten the image and the power consumption due to the output increase for increasing the luminous brightness can be reduced. The visible light transmittance T1 of the low transmittance layer is, for example, 80% or less, and may be 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less.

[0021] Also, examples of the other layer include an adhesive layer and a curable resin layer other than the curable resin layer (A). Each layer constituting the resin layer for sealing may be a single layer in the resin layer for sealing, or may be a multi-layer having the same or different compositions. When the multi-layers are included, the multi-layers may be laminated in contact with each other, or may be laminated separately (for example, two curable resin layers (A) are laminated via one adhesive layer). In this specification, a curable resin layer other than the curable resin layer (A) that the resin layer for sealing may include, that is, a curable resin layer that does not provide the second surface, may be referred to as a "curable resin layer (B)". The adhesive layer and the curable resin layer (B) may be the low transmittance layer.

[0022] The optical semiconductor element encapsulation sheet includes a release liner attached to the surface (second surface) of the encapsulating resin layer opposite the optical semiconductor element encapsulation surface. The release liner has an uneven surface with an uneven shape on the second surface (the surface to be attached to the curable resin layer (A)). That is, the uneven surface of the release liner having an uneven surface is attached to the second surface of the encapsulating resin layer. The curable resin layer (A) is in contact with the uneven surface of the release liner. By attaching the release liner having an uneven surface to the curable resin layer (A), the uneven shape of the release liner can be transferred to the cured layer surface of the curable resin layer (A) by peeling the release liner after curing the curable resin layer (A), thereby forming an uneven shape. By having an uneven shape on the second surface after peeling off the release liner, excellent antiglare properties can be exhibited even without a substrate with an antiglare layer, and by not having a substrate with an antiglare layer, changes in color due to interactions between the antiglare layer and the substrate can be avoided, allowing excellent color uniformity to be exhibited. Furthermore, by using a curable resin layer as the layer providing the second surface, after the curable resin layer has cured and the release liner has been peeled off, the surface is free of tackiness, providing excellent handleability and preventing dust and the like from adhering.

[0023] The arithmetic mean roughness Ra of the uneven surface of the release liner is preferably 0.2 μm or more, more preferably 0.3 μm or more, even more preferably 0.6 μm or more, and particularly preferably 0.8 μm or more. When the arithmetic mean roughness Ra is 0.2 μm or more, the antiglare properties are improved. The arithmetic mean roughness Ra is, for example, 10 μm or less, and may be 6 μm or less, 4 μm or less, or 2 μm or less.

[0024] In this specification, the arithmetic mean roughness Ra (the arithmetic mean roughness Ra of the textured surface of the release liner and the arithmetic mean roughness Ra of the textured surface of the cured resin layer described below) is measured using a non-contact surface roughness measuring device. As the non-contact surface roughness measuring device, an optical interference type surface roughness measuring device can be used, such as a 3D measuring laser microscope (trade name "LEXT OLS5000", manufactured by Olympus Corporation) or an equivalent. Specific measurement procedures and conditions can be set according to the measurement conditions described in the examples below, or so as to obtain results equivalent to or corresponding to those obtained when these measurement conditions are followed.

[0025] The encapsulating resin layer may include a curable resin layer (B) on the first surface side of the curable resin layer (A), and in this case, it is more preferable to include a curable resin layer (B) that provides the first surface. With such a configuration, the curable resin layer (B) flows during encapsulation of the optical semiconductor element to fill the gap between the optical semiconductor element and the substrate, and the curable resin layer (A) can fill the gap between adjacent optical semiconductor elements that may be generated by the flow of the curable resin layer (B).

[0026] Fig. 1 is a cross-sectional view showing one embodiment of the optical semiconductor element encapsulation sheet of the present invention. As shown in Fig. 1, the optical semiconductor element encapsulation sheet 1 can be used to encapsulate one or more optical semiconductor elements arranged on a substrate.

[0027] In the optical semiconductor element encapsulation sheet 1 shown in FIG. 1, the encapsulating resin layer 2 is formed from a laminate of a curable resin layer (A) 21 and a curable resin layer (B) 22. The encapsulating resin layer 2 has an optical semiconductor element encapsulation surface (first surface) 2a and a surface (second surface) 2b opposite the first surface. A release liner 4 is attached to the curable resin layer (A) 21, and a release liner 3 is attached to the curable resin layer (B) 22. The release liner 4 has an uneven surface 4a, and the uneven surface 4a of the release liner 4 is attached to the second surface 2b of the encapsulating resin layer 2. The curable resin layer (A) 21 provides the second surface 2b of the encapsulating resin layer 2 and is in contact with the uneven surface 4a of the release liner 4.

[0028] (curable resin layer) Examples of the curable resin layer (curable resin layer (A) and curable resin layer (B)) in the encapsulating resin layer include a thermosetting resin layer having thermosetting properties and an active energy ray-curable resin layer having active energy ray-curing properties. Examples of the active energy rays include electron beams, ultraviolet rays, α rays, β rays, γ rays, and X-rays. Among these, a thermosetting resin layer is preferred from the viewpoint of ease of curing after being attached to an optical semiconductor element.

[0029] Resins constituting the curable resin layer include known or commonly used resins, such as acrylic resins, urethane acrylate resins, urethane resins, rubber resins, epoxy resins, epoxy acrylate resins, oxetane resins, silicone resins, silicone acrylic resins, polyester resins, polyether resins (such as polyvinyl ether), polyamide resins, fluorine-containing resins, vinyl acetate / vinyl chloride copolymers, and modified polyolefins. Only one of the above resins may be used, or two or more may be used. Among these, acrylic resins are preferred.

[0030] The acrylic resin is a resin containing a structural unit derived from an acrylic monomer (a monomer component having a (meth)acryloyl group or a structure convertible thereto in the molecule) as a structural unit of the resin (polymer). Only one type of the acrylic resin may be used, or two or more types may be used.

[0031] The acrylic resin is preferably a resin containing the most structural units derived from (meth)acrylic acid esters by mass. In this specification, "(meth)acrylic" refers to "acrylic" and / or "methacrylic" (either one or both of "acrylic" and "methacrylic"), and the same applies to other terms.

[0032] The curable resin layer preferably contains a thermosetting resin, since it is preferable that the curable resin layer has thermosetting properties. As the thermosetting resin, a known or commonly used thermosetting resin can be used, for example, a resin having a thermosetting functional group. Among them, an acrylic resin having a thermosetting functional group (a thermosetting functional group-containing acrylic resin) is preferred as the thermosetting resin.

[0033] Examples of the thermosetting functional group include epoxy group-containing groups such as glycidyl groups, carboxy groups, hydroxy groups, isocyanate groups, and aziridyl groups. Among these, epoxy group-containing groups are preferred, and glycidyl groups are more preferred. That is, as an acrylic resin having a thermosetting functional group, a glycidyl group-containing acrylic resin is particularly preferred. The thermosetting functional group may be one type or two or more types.

[0034] The thermosetting functional group-containing acrylic resin preferably contains a structural unit derived from a monomer having a thermosetting functional group, and more preferably contains a structural unit derived from an acrylic monomer having a thermosetting functional group (a thermosetting functional group-containing acrylic monomer). Examples of the monomer having a thermosetting functional group include epoxy group-containing (meth)acrylic esters such as glycidyl group-containing (meth)acrylic esters, carboxy group-containing monomers, acid anhydride group-containing monomers, and hydroxy group-containing (meth)acrylic esters.

[0035] Examples of the glycidyl group-containing (meth)acrylic acid ester include glycidyl (meth)acrylate and methylglycidyl (meth)acrylate.

[0036] Examples of the carboxy group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc. Examples of the acid anhydride group-containing monomer include maleic anhydride, itaconic anhydride, etc.

[0037] Examples of the hydroxy group-containing (meth)acrylic acid ester include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate.

[0038] Among the thermosetting functional group-containing acrylic monomers, epoxy group-containing (meth)acrylic esters are preferred, and glycidyl group-containing (meth)acrylic esters are more preferred. When the acrylic resin contains a structural unit derived from an epoxy group-containing (meth)acrylic ester, the epoxy group acts as a thermosetting functional group, and even without a curing agent, the reaction of the epoxy group proceeds by thermal curing, resulting in the curing of the curable resin layer. Therefore, the curable resin layer has appropriate flexibility after thermal curing, and is superior in encapsulating optical semiconductor elements.

[0039] The content of the structural units derived from the epoxy group-containing (meth)acrylic acid ester is preferably 5 to 50 mass %, more preferably 6 to 45 mass %, relative to the total amount (100 mass %) of all structural units of the acrylic resin in the curable resin layer. When the content is within this range, the curable resin layer has appropriate flexibility after thermal curing and is more excellent in sealing the optical semiconductor element.

[0040] The thermosetting functional group-containing acrylic resin may contain a constituent unit derived from a monomer other than the thermosetting functional group-containing monomer. Examples of the other monomer include (meth)acrylic acid esters other than the thermosetting functional group-containing acrylic monomer. The other monomers may be used singly or in combination of two or more.

[0041] Examples of the other (meth)acrylic acid esters include hydrocarbon group-containing (meth)acrylic acid esters which may have an alkoxy group. Examples of the hydrocarbon group-containing (meth)acrylic acid esters in the hydrocarbon group-containing (meth)acrylic acid esters which may have an alkoxy group include (meth)acrylic acid alkyl esters having a linear or branched aliphatic hydrocarbon group, (meth)acrylic acid esters having an alicyclic hydrocarbon group such as (meth)acrylic acid cycloalkyl esters, and (meth)acrylic acid esters having an aromatic hydrocarbon group such as (meth)acrylic acid aryl esters. The hydrocarbon group-containing (meth)acrylic acid esters which may have an alkoxy group may be used singly or in combination of two or more.

[0042] Examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and methyl (meth)acrylate. Examples of the acrylate include isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate.

[0043] Among the above-mentioned (meth)acrylic acid alkyl esters, (meth)acrylic acid alkyl esters having a linear or branched aliphatic hydrocarbon group with a carbon number of 1 to 20 (preferably 1 to 14, more preferably 2 to 10, and even more preferably 2 to 8) are preferred. When the carbon number is within the above range, the flexibility of the thermosetting functional group-containing acrylic resin during heat curing is more likely to be more appropriate, and the embeddability is further improved.

[0044] Examples of the (meth)acrylic acid ester having an alicyclic hydrocarbon group include (meth)acrylic acid esters having a monocyclic aliphatic hydrocarbon ring such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate; (meth)acrylic acid esters having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth)acrylate; and (meth)acrylic acid esters having a tricyclic or higher aliphatic hydrocarbon ring such as dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, tricyclopentanyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate.

[0045] Examples of the (meth)acrylic acid ester having an aromatic hydrocarbon group include (meth)acrylic acid phenyl ester and (meth)acrylic acid benzyl ester.

[0046] Examples of hydrocarbon group-containing (meth)acrylic acid esters having alkoxy groups include those in which one or more hydrogen atoms in the hydrocarbon group of the above hydrocarbon group-containing (meth)acrylic acid esters have been substituted with alkoxy groups, such as 2-methoxymethyl ester, 2-methoxyethyl ester, and 2-methoxybutyl ester of (meth)acrylic acid.

[0047] Examples of the other monomer components include polar group-containing monomers such as sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, and nitrogen atom-containing monomers. Examples of the sulfonic acid group-containing monomers include styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid. Examples of the phosphoric acid group-containing monomers include 2-hydroxyethyl acryloyl phosphate. Examples of the nitrogen atom-containing monomers include morpholino group-containing monomers such as (meth)acryloylmorpholine, cyano group-containing monomers such as (meth)acrylonitrile, and amide group-containing monomers such as (meth)acrylamide.

[0048] The thermosetting functional group-containing acrylic resin may contain a structural unit derived from a polyfunctional (meth)acrylate copolymerizable with the monomer components constituting the acrylic resin to form a crosslinked structure in the polymer skeleton. Examples of the polyfunctional (meth)acrylate include hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. The polyfunctional (meth)acrylate may be used alone or in combination of two or more.

[0049] The thermosetting functional group-containing acrylic resin is obtained by polymerizing the above-mentioned various monomer components. The polymerization method is not particularly limited, but examples thereof include solution polymerization, emulsion polymerization, bulk polymerization, and polymerization by active energy ray irradiation (active energy ray polymerization). The obtained acrylic resin may be any of random copolymers, block copolymers, graft copolymers, etc.

[0050] The weight-average molecular weight of the epoxy group-containing acrylic resin is preferably 2,000 to 400,000, more preferably 30,000 to 300,000, from the viewpoint of providing a certain degree of hardness after curing of the curable resin layer and reducing adhesion between the side surfaces of the optical semiconductor device. When the weight-average molecular weight is within the above range, the embedding ability of the optical semiconductor element is superior. The weight-average molecular weight is measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene.

[0051] The content of the epoxy group-containing acrylic resin is preferably 40% by mass or more (for example, 40 to 100% by mass) relative to the total amount (100% by mass) of resin in the curable resin layer, more preferably 50% by mass or more, and even more preferably 60% by mass or more. When the content is 40% by mass or more, the embeddability of the optical semiconductor element is superior.

[0052] The curable resin layer preferably contains a component having a functional group (second functional group) that can react with the thermosetting functional group (first functional group) in the thermosetting functional group-containing acrylic resin by heat. The second functional group is also a thermosetting functional group. In this case, the first functional group reacts with the second functional group when the curable resin layer is heated, thereby further promoting the curing of the curable resin layer.

[0053] The component having the second functional group may be a thermosetting functional group-containing acrylic resin having the first functional group, a thermosetting functional group-containing acrylic resin other than the thermosetting functional group-containing acrylic resin having the first functional group, or another component having a second functional group. Only one type of component having the second functional group may be used, or two or more types may be used.

[0054] Examples of combinations of the first functional group and the second functional group include a carboxy group and an epoxy group, an epoxy group and a carboxy group, a carboxy group and an aziridyl group, an aziridyl group and a carboxy group, a hydroxy group and an isocyanate group, an isocyanate group and a hydroxy group, etc. The combinations may be of only one type or two or more types.

[0055] When the curable resin layer contains the epoxy group-containing acrylic resin, the curable resin layer preferably contains a component having a functional group reactive with an epoxy group as the component having the second functional group. Examples of the functional group reactive with an epoxy group include a carboxy group, an aziridyl group, and a hydroxy group. Among these, a carboxy group and a hydroxy group are preferred. As the hydroxy group, a silanol group is preferred from the viewpoint of high acidity and excellent reactivity with an epoxy group.

[0056] The component having a carboxy group is preferably the resin described above, more preferably a carboxy group-containing acrylic resin. The inclusion of the carboxy group-containing acrylic resin facilitates the reaction between the epoxy group and the carboxy group in the epoxy group-containing acrylic resin, even without a curing agent, and provides superior sealing of optical semiconductor elements. Furthermore, the surface scratch resistance is further improved.

[0057] The carboxyl group-containing acrylic resin preferably contains a structural unit derived from a carboxyl group-containing monomer, more preferably a structural unit derived from a carboxyl group-containing acrylic monomer, such as acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, or crotonic acid.

[0058] The content of the structural units derived from the carboxyl group-containing acrylic monomer is preferably 1 to 50 mass %, more preferably 2 to 40 mass %, relative to the total amount (100 mass %) of all structural units of the carboxyl group-containing acrylic resin. When the content is within the above range, the curable resin layer has appropriate flexibility after thermal curing and is superior in encapsulating the optical semiconductor element.

[0059] The carboxyl group-containing acrylic resin may contain a constituent unit derived from a monomer other than the carboxyl group-containing monomer. Examples of the other monomer include (meth)acrylic acid esters other than the thermosetting functional group-containing acrylic monomer, the polar group-containing monomers, and the polyfunctional (meth)acrylates. The other monomers may be used singly or in combination of two or more.

[0060] Examples of the other (meth)acrylic acid esters include the hydrocarbon group-containing (meth)acrylic acid esters which may have an alkoxy group. As the (meth)acrylic acid alkyl esters in the hydrocarbon group-containing (meth)acrylic acid esters which may have an alkoxy group, (meth)acrylic acid alkyl esters having a linear or branched aliphatic hydrocarbon group with 1 to 20 carbon atoms (preferably 1 to 14, more preferably 1 to 10, and even more preferably 1 to 8) are preferred. When the carbon number is within the above range, the flexibility of the thermosetting functional group-containing acrylic resin is more easily made appropriate, and embeddability is further improved.

[0061] In order to properly exhibit basic properties such as adhesion to the optical semiconductor element in the curable resin layer, the proportion of the hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group relative to the total amount (100% by mass) of all structural units of the carboxy group-containing acrylic resin is preferably 50 to 95% by mass, more preferably 60 to 90% by mass.

[0062] The weight-average molecular weight of the carboxyl group-containing acrylic resin is preferably 1,000 to 200,000, and more preferably 3,000 to 100,000. When the weight-average molecular weight is within the above range, the sealing properties of the optical semiconductor element are superior. The weight-average molecular weight is measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene.

[0063] When the carboxyl group-containing acrylic resin is contained, the content of the carboxyl group-containing acrylic resin is preferably 5 to 60 mass %, more preferably 10 to 50 mass %, and even more preferably 25 to 45 mass %, relative to the total amount (100 mass %) of resin in the curable resin layer. When the content is within the above range, the curable resin layer has better thermosetting properties and better scratch resistance.

[0064] The curable resin layer may contain other components in addition to the above-mentioned components, as long as the effects of the present invention are not impaired. Examples of the other components include colorants, crosslinking agents, thermoplastic resins, coupling agents such as silane coupling agents, crosslinking accelerators, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), oligomers, antioxidants, fillers (organic fillers, inorganic particles, etc.), light-diffusing fine particles, antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, UV absorbers, polymerization inhibitors, granular materials, foil-like materials, etc. The other components may each be used alone or in combination of two or more.

[0065] The content of the curable resin in the curable resin layer is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, relative to the total amount (100% by mass) of the curable resin layer. The content is preferably 99.99% by mass or less, more preferably 99% by mass or less, and even more preferably 95% by mass or less. The content of the acrylic resin is preferably within the above range, the content of the thermosetting resin is preferably within the above range, and the content of the thermosetting functional group-containing acrylic resin is preferably within the above range.

[0066] The curable resin layer may be a colored resin layer or a non-colored resin layer. The curable resin layer (A) is preferably a non-colored resin layer. The non-colored resin layer is a layer different from the colored layer and is not intended to prevent light reflection by metal wiring or the like. The non-colored resin layer may be a colorless layer or may be slightly colored. Furthermore, the non-colored resin layer may be, for example, a diffusion functional layer intended to exhibit the function of diffusing light, or may be a non-diffusion functional layer intended not to exhibit the function of diffusing light. The non-colored resin layer may be transparent or non-transparent.

[0067] The content of the colorant in the non-colored resin layer is preferably less than 0.2% by mass, more preferably less than 0.1% by mass, and even more preferably less than 0.05% by mass, relative to the total amount (100% by mass) of the non-colored resin layer, and may be less than 0.01% by mass or less than 0.005% by mass.

[0068] The total light transmittance of the non-colored resin layer is not particularly limited, but from the viewpoint of ensuring brightness, it is preferably 40% or more, more preferably 60% or more, even more preferably 70% or more, and particularly preferably 80% or more. The upper limit of the total light transmittance of the non-colored resin layer is not particularly limited, but it may be less than 100%, 99.9% or less, or 99% or less.

[0069] The total light transmittance of the non-colored resin layer is a value for a single layer, and can be measured by the method specified in JIS K7136 and JIS K7361-1, and can be controlled by the type and thickness of the non-colored resin layer.

[0070] The diffusion functional layer is a layer intended to diffuse light. When the curable resin layer is the diffusion functional layer, light emitted from the optical semiconductor element is diffused in the diffusion functional layer, and for example, light emitted from the side surface of the optical semiconductor element is emitted toward the front of the image display device, thereby improving the front brightness of the image display device. The diffusion functional layer is not limited, but preferably contains light-diffusing fine particles. That is, the diffusion functional layer preferably contains light-diffusing fine particles dispersed in the curable resin layer. Only one type of light-diffusing fine particles may be used, or two or more types may be used.

[0071] The light-diffusing fine particles have an appropriate refractive index difference from the resin constituting the diffusion functional layer, and impart diffusion properties to the diffusion functional layer. Examples of the light-diffusing fine particles include inorganic fine particles and polymer fine particles. Examples of materials for the inorganic fine particles include silica, calcium carbonate, aluminum hydroxide, magnesium hydroxide, clay, talc, and metal oxides. Examples of materials for the polymer fine particles include silicone resin, acrylic resin (including polymethacrylate resin such as polymethyl methacrylate), polystyrene resin, polyurethane resin, melamine resin, polyethylene resin, and epoxy resin.

[0072] The polymeric fine particles are preferably fine particles made of silicone resin. The inorganic fine particles are preferably fine particles made of metal oxide. The metal oxide is preferably titanium oxide or barium titanate, more preferably titanium oxide. This structure provides the diffusion layer with superior light diffusion properties and reduces brightness unevenness.

[0073] The shape of the light-diffusing fine particles is not particularly limited, and may be, for example, spherical, flat, or irregular.

[0074] The average particle diameter of the light-diffusing fine particles is preferably 0.1 μm or more, more preferably 0.15 μm or more, even more preferably 0.2 μm or more, and particularly preferably 0.25 μm or more, from the viewpoint of imparting appropriate light diffusion performance. Furthermore, the average particle diameter of the light-diffusing fine particles is preferably 12 μm or less, more preferably 10 μm or less, and even more preferably 8 μm or less, from the viewpoint of preventing the haze value from becoming too high and displaying high-resolution images. The average particle diameter can be measured, for example, using a Coulter counter.

[0075] The refractive index of the light-diffusing fine particles is preferably 1.2 to 5, more preferably 1.25 to 4.5, even more preferably 1.3 to 4, and particularly preferably 1.35 to 3.

[0076] The absolute value of the refractive index difference between the light-diffusing fine particles and the resin constituting the diffusion functional layer (the curable resin layer excluding the light-diffusing fine particles in the diffusion functional layer) is preferably 0.001 or more, more preferably 0.01 or more, even more preferably 0.02 or more, particularly preferably 0.03 or more, and may be 0.04 or more, or 0.05 or more, from the viewpoint of more efficiently reducing brightness unevenness in the image display device. Furthermore, the absolute value of the refractive index difference between the light-diffusing fine particles and the resin is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less, from the viewpoint of preventing the haze value from becoming too high and displaying a high-definition image.

[0077] From the viewpoint of imparting appropriate light diffusion performance to the sheet for encapsulating optical semiconductor elements, the content of the light-diffusing fine particles in the diffusion functional layer is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, even more preferably 0.1 parts by mass or more, and particularly preferably 0.15 parts by mass or more, relative to 100 parts by mass of the resin constituting the diffusion functional layer. Moreover, from the viewpoint of preventing the haze value from becoming too high and displaying a high-resolution image, the content of the light-diffusing fine particles is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, relative to 100 parts by mass of the resin constituting the diffusion functional layer.

[0078] The haze value (50 μm thick) of the diffusion functional layer is not particularly limited, but from the viewpoint of efficiently reducing brightness unevenness, it is preferably 30% or more, more preferably 40% or more, even more preferably 50% or more, and particularly preferably 60% or more. It may be 70% or more, 80% or more, 90% or more, 95% or more, or 97% or more, and a value around 99.9% is preferable because it has a better effect of improving brightness unevenness. The upper limit of the haze value of the diffusion functional layer is not particularly limited, and may be 100%. The haze value may be a value before or after curing, but is preferably a value after curing.

[0079] The total light transmittance of the diffusion functional layer is not particularly limited, but from the viewpoint of ensuring brightness, it is preferably 40% or more, more preferably 60% or more, even more preferably 70% or more, and particularly preferably 80% or more. The upper limit of the total light transmittance of the diffusion functional layer is not particularly limited, but it may be less than 100%, 99.9% or less, or 99% or less.

[0080] The haze value and total light transmittance of the above-mentioned diffusion functional layer are values ​​for a single layer and can be measured by the methods specified in JIS K7136 and JIS K7361-1. They can be controlled by the type and thickness of the diffusion functional layer, the type and amount of light-diffusing microparticles, etc.

[0081] The haze value (50 μm thick) of the non-diffusion functional layer is not particularly limited, but from the viewpoint of achieving excellent brightness, it is preferably less than 30%, more preferably 10% or less, even more preferably 5% or less, particularly preferably 1% or less, and may be 0.5% or less. The lower limit of the haze value of the non-diffusion functional layer is not particularly limited.

[0082] The total light transmittance of the non-diffusion functional layer is not particularly limited, but from the viewpoint of ensuring brightness, it is preferably 60% or more, more preferably 70% or more, even more preferably 80% or more, and particularly preferably 90% or more. Furthermore, the upper limit of the total light transmittance of the non-diffusion functional layer is not particularly limited, but it may be less than 100%, 99.9% or less, or 99% or less.

[0083] The haze value and total light transmittance of the non-diffusion functional layer are values ​​for a single layer, and can be measured by the methods specified in JIS K7136 and JIS K7361-1. They can be controlled by the type and thickness of the non-diffusion functional layer.

[0084] In order to improve the brightness of the image display device, the content of the colorant and / or light-diffusing microparticles in the non-diffusion functional layer is preferably less than 0.01 parts by mass, and more preferably less than 0.005 parts by mass, per 100 parts by mass of the resin constituting the non-diffusion functional layer.

[0085] The light transmittance at a wavelength of 600 nm of the non-colored resin layer (thickness: 50 μm) after curing is not particularly limited, but from the viewpoint of further improving the brightness of the optical semiconductor device, it is preferably more than 80%, more preferably 85% or more, and even more preferably 90% or more. The light transmittance is 100% or less.

[0086] (Curable resin layer (A)) The acrylic resin that can be contained in the curable resin layer (A) may have a structural moiety derived from a crosslinking agent. For example, the acrylic resin can be crosslinked to further reduce low-molecular-weight substances in the curable resin layer. Furthermore, the weight-average molecular weight of the acrylic resin can be increased, thereby reducing fluidity during encapsulation. When the acrylic resin has active energy ray-polymerizable functional groups, the crosslinking agent crosslinks functional groups other than the active energy ray-polymerizable functional groups (e.g., between third functional groups, between fourth functional groups, or between a third functional group and a fourth functional group). Only one type of crosslinking agent may be used, or two or more types may be used.

[0087] Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, a melamine-based crosslinking agent, a peroxide-based crosslinking agent, a urea-based crosslinking agent, a metal alkoxide-based crosslinking agent, a metal chelate-based crosslinking agent, a metal salt-based crosslinking agent, a carbodiimide-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, an amine-based crosslinking agent, a silicone-based crosslinking agent, and a silane-based crosslinking agent. Among these, from the viewpoints of easy adjustment of the degree of crosslinking and low impurity ions, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred as the crosslinking agent, and isocyanate-based crosslinking agents are more preferred.

[0088] Examples of the isocyanate-based crosslinking agent (polyfunctional isocyanate compound) include lower aliphatic polyisocyanates such as 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate; alicyclic polyisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated xylene diisocyanate; and aromatic polyisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate. Examples of the isocyanate crosslinking agent include a trimethylolpropane / tolylene diisocyanate adduct, a trimethylolpropane / hexamethylene diisocyanate adduct, and a trimethylolpropane / xylylene diisocyanate adduct.

[0089] The content of the structural part derived from the crosslinking agent is not particularly limited, but is preferably 10 parts by mass or less, more preferably 0.001 to 10 parts by mass, and even more preferably 0.01 to 7 parts by mass, relative to 100 parts by mass of the total amount of the acrylic resin excluding the structural part derived from the crosslinking agent.

[0090] The thickness of the curable resin layer (A) is preferably 10 to 150 μm, more preferably 15 to 130 μm, and even more preferably 20 to 120 μm. If the thickness is 10 μm or more, a large amount of the curable resin layer remains between the optical semiconductor elements during encapsulation, making it difficult for gaps to form between the optical semiconductor elements. If the thickness is 150 μm or less, the brightness of the light emitted by the optical semiconductor elements will be higher.

[0091] (Curable resin layer (B)) The curable resin layer (B), which may be positioned closer to the first surface than the curable resin layer (A), preferably has a viscosity at the sealing temperature of 2 to 2000 kPa·s, more preferably 3 to 1500 kPa·s, and even more preferably 10 to 1200 kPa·s. When the viscosity is 2 kPa or higher, the fluidity of the curable resin layer (B) is not too low, making it difficult for voids to form between adjacent optical semiconductor elements. Furthermore, when the viscosity is 2000 kPa or lower, the curable resin layer (B) flows during sealing of the optical semiconductor elements, filling the voids between the optical semiconductor elements and the substrate. The sealing temperature is preferably 35 to 120°C, more preferably 40 to 110°C, even more preferably 60 to 105°C, and particularly preferably 70 to 100°C. In other words, the viscosity at at least one point between 35 and 120°C (preferably 40 to 110°C, more preferably 60 to 105°C, and even more preferably 70 to 100°C) is preferably within the above range. The viscosity can be controlled, for example, by the monomer composition and weight average molecular weight of the resin constituting the resin composition for forming the curable resin layer (B), the amount (addition amount) of the polyfunctional monomer and crosslinking agent used, and the type and content of other additives.

[0092] The curable resin layer (B) may contain a colorant. For example, if the curable resin layer (B) contains a colorant, it can prevent light reflection from metal wiring or the like provided on a substrate in an image display device. Furthermore, if the curable resin layer (B) is a colored layer containing a colorant, when the optical semiconductor element is encapsulated, the colored layer fills the gap between the optical semiconductor element and the substrate, while leaving a thin layer on the top and side surfaces of the optical semiconductor element. This can further suppress optical interference between the optical semiconductor elements, improving the appearance of the optical semiconductor device.

[0093] The colorant may be either a dye or a pigment, as long as it is soluble or dispersible in the curable resin layer (B). Dyes are preferred because they can achieve low haze even with a small amount added, do not settle like pigments, and are easily distributed uniformly. Pigments are also preferred because they provide high color expression even with a small amount added. When using a pigment as the colorant, it is preferable that it has low or no conductivity. One or more of the above colorants may be used.

[0094] The colorant is preferably a black colorant. Known or commonly used colorants (pigments, dyes, etc.) for producing black can be used as the black colorant, including, for example, carbon black (furnace black, channel black, acetylene black, thermal black, lamp black, pine soot, etc.), graphite, copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (non-magnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complexes, anthraquinone-based colorants, and zirconium nitride. Alternatively, a colorant functioning as a black colorant may be used by combining and blending colorants producing colors other than black.

[0095] When the curable resin layer (B) is an active energy ray-curable resin layer, the colorant preferably absorbs visible light and transmits light of a wavelength at which the active energy ray-curable resin layer can be cured.

[0096] From the viewpoint of imparting an appropriate anti-reflection property to the image display device, the content of the colorant in the curable resin layer (B) is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, relative to the total amount (100% by mass) of the curable resin layer (B). The content of the colorant is, for example, 5% by mass or less, preferably 1% by mass or less, and more preferably 0.5% by mass or less. The content may be appropriately set depending on the type of colorant, the color tone and light transmittance of the image display device, and the like. The colorant may be added to the composition as a solution or dispersion in which it is dissolved or dispersed in an appropriate solvent.

[0097] The thickness of the curable resin layer (B) is preferably 60% or more, more preferably 70% or more, of the distance from the surface of the substrate to the apex of the optical semiconductor element. If the thickness is 60% or more, a large amount of the curable resin layer remains between the optical semiconductor elements during encapsulation, making it less likely that gaps will form between the optical semiconductor elements. The thickness is, for example, 130% or less, preferably 120% or less, more preferably 110% or less, of the distance from the surface of the substrate to the apex of the optical semiconductor element. If the thickness is 130% or less, the brightness of the light emitted by the optical semiconductor element will be higher.

[0098] The thickness of the curable resin layer (B) is preferably 50 to 150 μm, more preferably 60 to 130 μm, and even more preferably 70 to 120 μm. If the thickness is 50 μm or more, a large amount of the curable resin layer remains between the optical semiconductor elements during encapsulation, making it difficult for gaps to form between the optical semiconductor elements. If the thickness is 150 μm or less, the brightness of the light emitted by the optical semiconductor elements will be higher.

[0099] <Optical semiconductor element encapsulation sheet> The optical semiconductor element encapsulation sheet may include a layer having antiglare and / or antireflection properties within the scope of the present invention, without impairing the effects of the present invention. Such a configuration can suppress gloss and light reflection when encapsulating an optical semiconductor element, thereby further improving the appearance. An example of the antiglare layer is an antiglare-treated layer. An example of the antireflection layer is an antireflection-treated layer. The antiglare treatment and the antireflection treatment can be performed by known or conventional methods. The antiglare layer and the antireflection layer may be the same layer or different layers. The sheet may have only one antiglare and / or antireflection layer, or two or more layers. The antiglare and / or antireflection layer is preferably provided on the second surface of the encapsulating resin layer (between the curable resin layer (A) and the release liner). The layer having antiglare and / or antireflection properties can be formed in advance on the uneven surface of the release liner, and then transferred to the second surface of the encapsulating resin layer when the release liner is peeled off.

[0100] The haze value of the optical semiconductor element encapsulation sheet is not particularly limited, but from the viewpoint of achieving a superior effect of suppressing brightness unevenness and designability, it is preferably 0.5% or more, more preferably 1% or more, and even more preferably 3% or more. The upper limit of the haze value is not particularly limited, and may be 100%, 80%, 60%, or 40%. The haze value may be a value before or after curing, but is preferably a value after curing.

[0101] The total light transmittance of the sheet for encapsulating an optical semiconductor element is not particularly limited, but is preferably 40% or less, more preferably 30% or less, and even more preferably 20% or less, from the viewpoint of further improving the anti-reflection function of metal wiring etc. and contrast. Moreover, the total light transmittance is preferably 0.5% or more, from the viewpoint of ensuring brightness.

[0102] The haze value and total light transmittance can be measured by the methods specified in JIS K7136 and JIS K7361-1, respectively, and can be controlled by the stacking order, type, thickness, etc. of each layer constituting the encapsulating resin layer.

[0103] In the sheet for encapsulating an optical semiconductor element, when the optical semiconductor element is encapsulated, the distance from the optical semiconductor element to the curable resin layer (B) is preferably 0 to 20 μm, more preferably 0 to 10 μm. When the distance is within the above range, the antireflection property and brightness of the image display device are superior.

[0104] The thickness of the optical semiconductor element encapsulation sheet (thickness from the first surface to the second surface of the encapsulating resin layer) is preferably 5 to 600 μm, more preferably 10 to 550 μm, even more preferably 30 to 500 μm, still more preferably 40 to 450 μm, and particularly preferably 50 to 400 μm, from the viewpoints of improving the anti-reflection function and contrast of metal wiring and the like while more efficiently reducing color shift. Note that the thickness does not include the thickness of the release liner.

[0105] The thickness of the encapsulating resin layer is, for example, 5 to 500 μm, preferably 10 to 400 μm, and more preferably 100 to 300 μm. When the thickness is 5 μm or more, the encapsulation of the optical semiconductor element is improved. When the thickness is 500 μm or less, the thickness of the optical semiconductor device is thinner.

[0106] [Release liner] As described above, the second surface of the encapsulating resin layer is protected by a release liner. The first surface of the encapsulating resin layer may be protected by a release liner. Alternatively, the encapsulating resin layer may be a rolled body in which both surfaces of the encapsulating resin layer are protected by contact with both surfaces of a single release liner. These release liners are used as protective materials for the optical semiconductor element encapsulation sheet and are peeled off when encapsulating the optical semiconductor element. The release liner on the first surface side is not necessarily provided.

[0107] The release liner is an element for covering and protecting the surface of the optical semiconductor element encapsulation sheet, and is peeled off from the sheet when the optical semiconductor element encapsulation sheet is attached to a substrate on which an optical semiconductor element is arranged.

[0108] Examples of the release liner include polyethylene terephthalate (PET) film, polyethylene film, polypropylene film, plastic film and paper whose surface is coated with a release agent such as a fluorine-based release agent or a long-chain alkyl acrylate-based release agent.

[0109] The thickness of the release liner is, for example, 10 to 200 μm, preferably 15 to 150 μm, and more preferably 20 to 100 μm. When the thickness is 10 μm or more, the release liner is less likely to break due to cuts during processing. When the thickness is 200 μm or less, the release liner is more easily peeled from the optical semiconductor element encapsulation sheet during use.

[0110] [Method of manufacturing the sheet for encapsulating optical semiconductor elements] An embodiment of a method for producing the optical semiconductor element encapsulation sheet will be described. For example, the optical semiconductor element encapsulation sheet 1 shown in FIG. 1 is produced by individually sandwiching a curable resin layer (A) 21 and a curable resin layer (B) 22 between the release-treated surfaces of two release liners. First, a resin composition for forming the curable resin layer (A) 21 is applied to the uneven surface 4a, which is the release-treated surface of the release liner 4, and then solidified to form the curable resin layer (A) 21 on the uneven surface 4a of the release liner 4. On the other hand, a resin composition for forming the curable resin layer (B) 22 is applied to the release-treated surface of the release liner 3 and then solidified to form the curable resin layer (B) 22 on the release-treated surface of the release liner 3. Next, the exposed surface of the curable resin layer (B) 22 is bonded to the exposed surface of the curable resin layer (A) 21. The various layers can be laminated using a known roller or laminator. In this manner, the sheet for encapsulating an optical semiconductor element 1 shown in Figure 1 can be produced, in which the release liner 4, the curable resin layer (A) 21, the curable resin layer (B) 22, and the release liner 3 are laminated in this order.

[0111] [Optical semiconductor device] The optical semiconductor device such as an image display device can be produced using the optical semiconductor element encapsulation sheet. The optical semiconductor device produced using the optical semiconductor element encapsulation sheet includes a substrate, an optical semiconductor element disposed on the substrate, and an optical semiconductor element encapsulation sheet that encapsulates the optical semiconductor element. The optical semiconductor element encapsulation sheet is the optical semiconductor element encapsulation sheet or a cured product thereof. The cured product is a cured product obtained by thermally curing the curable resin layer (A) (or further the curable resin layer (B)) included in the optical semiconductor element encapsulation sheet, and includes, for example, a cured encapsulating layer obtained by thermally curing the curable resin layer (A) 21 and the curable resin layer (B) 22.

[0112] When the optical semiconductor element encapsulating sheet is the cured product, the optical semiconductor element encapsulating sheet comprises an encapsulating resin layer including at least a cured resin layer that provides the second surface. The cured resin layer is a cured product of the curable resin layer (A), provides the second surface in the optical semiconductor device, and is an uneven surface having an uneven shape. In this specification, the cured resin layer that is a cured product of the curable resin layer (A) may be referred to as the "cured resin layer (A)."

[0113] The arithmetic mean roughness Ra of the uneven surface of the cured resin layer (A) is preferably 0.2 μm or more, more preferably 0.3 μm or more, even more preferably 0.5 μm or more, even more preferably 0.6 μm or more, and particularly preferably 0.7 μm or more. When the arithmetic mean roughness Ra is 0.2 μm or more, the antiglare properties are improved. The arithmetic mean roughness Ra is, for example, 10 μm or less, and may be 6 μm or less, 4 μm or less, or 2 μm or less.

[0114] Examples of the optical semiconductor element include light emitting diodes (LEDs) such as blue light emitting diodes, green light emitting diodes, red light emitting diodes, and ultraviolet light emitting diodes.

[0115] In the optical semiconductor device, the optical semiconductor element encapsulation sheet has excellent conformability to irregularities when the optical semiconductor elements are convex portions and the gaps between the multiple optical semiconductor elements are concave portions, and has excellent conformability and embeddability for the optical semiconductor elements, so it is preferable that the sheet encapsulates multiple optical semiconductor elements collectively.

[0116] 2 and 3 show an embodiment of an optical semiconductor device using the optical semiconductor element encapsulation sheet 1 shown in FIG. 1 . The optical semiconductor device 10 shown in FIG. 2 includes a substrate 5, multiple optical semiconductor elements 6 arranged on one surface of the substrate 5, and a cured product of the optical semiconductor element encapsulation sheet 1. The cured product of the optical semiconductor element encapsulation sheet is obtained by peeling the release liner 3 from the optical semiconductor element encapsulation sheet 1 and thermally curing the curable resin layer (A) 21 and the curable resin layer (B) 22 to form a cured encapsulating layer 7. For example, the cured encapsulating layer 7 is composed of a cured resin layer (A) 71 formed by thermally curing the curable resin layer (A) 21 and a cured resin layer (cured resin layer (B)) 72 formed by thermally curing the curable resin layer (B) 22. The multiple optical semiconductor elements 6 are encapsulated together in the cured encapsulating layer 7. The cured encapsulating layer 7 adheres closely to the optical semiconductor elements 6 and the substrate 5, conforming to the uneven shape formed by the multiple optical semiconductor elements 6, thereby embedding the optical semiconductor elements 6. Furthermore, the cured sealing layer 7 has an uneven surface on the optical semiconductor element 6 side in accordance with the uneven surface, and the other interface is flat.

[0117] The optical semiconductor device 10 shown in Figure 3 is in a state where the release liner 4 has been peeled off from the optical semiconductor device 10 shown in Figure 2, and the uneven shape of the uneven surface 4a of the release liner 4 has been transferred to the surface of the cured resin layer (A) 71.

[0118] 2 and 3, the optical semiconductor element 6 is completely embedded and sealed within the cured resin layer (A) 71 and the cured resin layer (B) 72, and is sealed by the cured resin layer (A) 71 and the cured resin layer (B) 72. That is, the optical semiconductor element 6 is sealed by the cured sealing layer 7 made of a laminate of the cured resin layer (A) 71 and the cured resin layer (B) 72. The cured resin layer (B) 72 fills the space between the optical semiconductor element 6 and the substrate 5, and the spaces between the multiple optical semiconductor elements 6 are filled with the cured resin layer (A) 71 and the cured resin layer (B) 72.

[0119] As described above, the optical semiconductor device encapsulates the optical semiconductor element with a cured encapsulating layer. The curable resin layer (A) has an uneven surface on the second surface after curing, resulting in excellent antiglare properties even without a substrate with an antiglare layer. Furthermore, the absence of a substrate with an antiglare layer eliminates color changes due to interactions between the antiglare layer and the substrate, resulting in excellent color uniformity. This results in excellent appearance for the optical semiconductor device.

[0120] The optical semiconductor device may be a tiled structure of individual optical semiconductor devices, i.e., the optical semiconductor device may be a structure in which a plurality of optical semiconductor devices are arranged in a tiled pattern in a planar direction.

[0121] The image display device preferably includes a self-luminous display device. The self-luminous display device can also be combined with a display panel, if necessary, to form an image display device. In this case, the optical semiconductor elements are LED elements. Examples of the self-luminous display device include LED displays, backlights, and organic electroluminescence (organic EL) display devices. The backlight is preferably a full-surface direct backlight. The backlight includes, as at least a part of its components, a laminate including the substrate and a plurality of optical semiconductor elements arranged on the substrate. For example, in the self-luminous display device, a metal wiring layer is laminated on the substrate for transmitting light emission control signals to each LED element. LED elements emitting red (R), green (G), and blue (B) light are alternately arranged on the substrate via the metal wiring layer. The metal wiring layer is made of a metal such as copper, and adjusts the light emission intensity of each LED element to display each color.

[0122] The optical semiconductor element encapsulation sheet can be used in an optical semiconductor device that is folded when used, for example, an optical semiconductor device having a foldable image display device (flexible display) (particularly, a foldable image display device (foldable display)). Specifically, it can be used in a foldable backlight and a foldable self-luminous display device.

[0123] The sheet for encapsulating optical semiconductor elements has excellent conformability and embeddability for optical semiconductor elements, and can therefore be preferably used when the optical semiconductor device is either a mini LED display device or a micro LED display device.

[0124] [Method of manufacturing optical semiconductor device] The optical semiconductor device can be produced by a production method including, for example, a step of bonding the optical semiconductor element encapsulation sheet to the optical semiconductor element provided on the substrate to encapsulate the optical semiconductor element with the encapsulating resin layer (encapsulation step), a step of curing the curable resin layer (A) in a laminate obtained through the encapsulation step and including the substrate, the optical semiconductor element disposed on the substrate, and the optical semiconductor element encapsulation sheet that encapsulates the optical semiconductor element to form a cured resin layer (A) (curing step), and a step of peeling off the release liner attached to the cured resin layer (A) to transfer the uneven surface to the cured resin layer (A) (transfer step).

[0125] The manufacturing method may further include a step of dicing the laminate that has undergone the curing step to obtain an optical semiconductor device (dicing step). The manufacturing method may also include a tiling step of arranging a plurality of optical semiconductor devices obtained in the dicing step so that they are in contact with each other in a planar direction. The manufacturing method for the optical semiconductor device 10 shown in FIG. 3 will be described below with reference to the manufacturing method for the optical semiconductor device 10 shown in FIG. 3.

[0126] (Sealing process) The method for producing an optical semiconductor device using the optical semiconductor element encapsulation sheet includes an encapsulating step of bonding the optical semiconductor element encapsulation sheet to a substrate on which an optical semiconductor element is arranged and encapsulating the optical semiconductor element with an encapsulating resin layer. Specifically, the encapsulating step first involves peeling off the release liner on the first surface side from the optical semiconductor element encapsulation sheet to expose the encapsulating resin layer. Then, of a laminate (such as an optical member) including a substrate and optical semiconductor elements (preferably multiple optical semiconductor elements) arranged on the substrate, the exposed surface of the optical semiconductor element encapsulation sheet is bonded to the substrate surface on which the optical semiconductor elements are arranged. If the laminate includes multiple optical semiconductor elements, the encapsulating resin layer is further arranged to fill gaps between the multiple optical semiconductor elements, thereby collectively encapsulating the multiple optical semiconductor elements. Specifically, the release liner 3 is peeled off from the sheet 1 for encapsulating optical semiconductor elements shown in Figure 1, and the exposed curable resin layer (B) 22 is placed opposite the surface of the substrate 5 on which the optical semiconductor element 6 is arranged, and the sheet 1 for encapsulating optical semiconductor elements is attached to the surface of the substrate 5 on which the optical semiconductor element 6 is arranged, and the optical semiconductor element 6 is embedded in the encapsulating resin layer 2 or adhered to it.

[0127] The temperature during the lamination (sealing temperature) is, for example, within a range from room temperature to 150°C, preferably 35 to 120°C, more preferably 40 to 110°C, even more preferably 60 to 105°C, and particularly preferably 70 to 100°C. The lamination may be performed under reduced pressure or pressure. This reduces or pressurizes the sheet for encapsulating an optical semiconductor element, preventing voids from forming between the encapsulating resin layer and the substrate or the optical semiconductor element. In the encapsulation step, the sheet is preferably laminated under reduced pressure and then pressurized. When reduced pressure is applied, the pressure is, for example, 1 to 100 Pa, and the depressurization time is, for example, 5 to 600 seconds. When pressurized, the pressure is, for example, 0.05 to 0.5 MPa, and the pressurization time is, for example, 5 to 600 seconds. This sealing step causes the curable resin layer (B) to flow at the sealing temperature and fill the space between the optical semiconductor element and the substrate.

[0128] (hardening process) In the curing step, the curable resin layer (A) is cured, for example, by heating, on a laminate (e.g., a laminate obtained in the encapsulation step) in which the optical semiconductor element encapsulation sheet is bonded to the substrate on which the optical semiconductor element is disposed. When the encapsulating resin layer includes a curable resin layer (B), the curable resin layer (B) is also cured. Specifically, in the curing step, as shown in FIG. 2, the curable resin layer (A) 21 and the curable resin layer (B) 22 are cured to form a cured encapsulating layer 7, and a cured product of the optical semiconductor element encapsulation sheet 1 (optical semiconductor element encapsulating sheet) is obtained. When the curable resin layer is thermosetting, the heating temperature during curing is, for example, within a range of 80 to 200°C, and the heating time is, for example, 1 minute to 24 hours.

[0129] (Transfer process) In the transfer step, the release liner attached to the cured resin layer (A) of the cured sealing layer is peeled off to transfer the textured surface to the cured resin layer (A). Specifically, in the transfer step, as shown in FIG. 3, the release liner 4 is peeled off from the cured resin layer (A) 71 to expose the cured resin layer (A) 71. Furthermore, by forming an antiglare and / or antireflective layer on the textured surface 4a of the release liner 4, the release liner 4 can be peeled off to transfer the antiglare and / or antireflective layer to the surface of the cured resin layer (A) 71 (the second surface of the cured sealing layer 7).

[0130] (dicing process) In the dicing step, the laminate that has undergone the curing step is diced. The dicing step may be performed after or before the transfer step. In the laminate that is subjected to the dicing step, the cured product of the optical semiconductor element encapsulation sheet and the substrate 5 extend wider in the planar direction than the optical semiconductor device 10 that will ultimately be obtained. In the dicing step, the side edges of the cured product of the optical semiconductor element encapsulation sheet and the substrate are diced and removed. The dicing can be performed by a known or conventional method, such as a method using a dicing blade or laser irradiation. In this manner, for example, the optical semiconductor device 10 shown in FIG. 3 can be manufactured.

[0131] (Tiling process) In the tiling step, the plurality of optical semiconductor devices obtained in the dicing step are tiled so as to be in contact with each other in the planar direction, thereby manufacturing, for example, one large image display device. [Example]

[0132] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0133] Example 1 (Preparation of Thermosetting Resin Layer A1) A resin composition solution having a solids concentration of 50% by mass was prepared by dissolving 63.9 parts by mass of an acrylic polymer (glycidyl methacrylate (GMA):ethyl acrylate (EA):butyl methacrylate (BMA) = 34% by mass:30% by mass:36% by mass, weight-average molecular weight 60,000), 34.1 parts by mass of an acrylic resin (trade name "UC-3000", carboxyl group-containing acrylic resin, weight-average molecular weight 10,000, manufactured by Toa Gosei Co., Ltd.), 2.0 parts by mass of a silane coupling agent (trade name "KBM-303", manufactured by Shin-Etsu Chemical Co., Ltd.), 5.1 parts by mass of an epoxy-based crosslinking agent (trade name "TETRAD-C", manufactured by Mitsubishi Gas Chemical Company, Inc.), and 20.0 parts by mass of a silicone resin (trade name "Tospearl 145", manufactured by Momentive Performance Materials Japan, Inc., refractive index: 1.42, average particle size: 4.5 μm) in methyl ethyl ketone. The resin composition solution was applied to the release-treated surface of release liner A (a PET film having a matte-treated surface and having been subjected to a release treatment on the matte-treated surface), and then dried at 130°C for 2 minutes to produce a sheet-like thermosetting resin layer A1 having a thickness (average thickness) of 25 μm.

[0134] (Preparation of Thermosetting Resin Layer B) 63.9 parts by mass of acrylic polymer (glycidyl methacrylate (GMA):ethyl acrylate (EA):butyl methacrylate (BMA) = 34% by mass:30% by mass:36% by mass, weight-average molecular weight 60,000), 19.1 parts by mass of acrylic resin (trade name "UC-3000", carboxyl group-containing acrylic resin, weight-average molecular weight 10,000, manufactured by Toa Gosei Co., Ltd.), 19.1 parts by mass of acrylic resin (trade name "UC-3510", carboxyl group-containing acrylic resin, weight-average molecular weight 2,000, manufactured by Toa Gosei Co., Ltd.) A resin composition solution with a solids concentration of 50% by weight was prepared by dissolving 15.0 parts by weight of a silane coupling agent (trade name "KBM-303" manufactured by Shin-Etsu Chemical Co., Ltd.), 2.0 parts by weight of a silane coupling agent (trade name "Carbon Black #20" manufactured by Mitsubishi Chemical Corporation), 0.35 parts by weight of a silicone resin (trade name "Tospearl 145" manufactured by Momentive Performance Materials Japan, Inc., refractive index: 1.42, average particle size: 4.5 μm) in methyl ethyl ketone. The resin composition solution was applied to the release-treated surface of release liner Z (a release-treated film consisting of a 38 μm-thick polyethylene terephthalate film treated with silicone release agent) and then dried at 130°C for 2 minutes to prepare a sheet-like thermosetting resin layer B with a thickness (average thickness) of 75 μm.

[0135] (Production of optical semiconductor element encapsulation sheet) The exposed surface of the thermosetting resin layer B was placed on the exposed surface of the thermosetting resin layer A1, and the sheets were laminated at room temperature (23°C) using a hand roller to avoid trapping air bubbles, and then left for two days in a dark place. In this way, a sheet for encapsulating an optical semiconductor element of Example 1 consisting of [release liner A / thermosetting resin layer A1 / thermosetting resin layer B / release liner Z] was obtained.

[0136] Example 2 (Production of optical semiconductor element encapsulation sheet) Example 2: A sheet for encapsulating optical semiconductor elements, consisting of [release liner B / thermosetting resin layer A1 / thermosetting resin layer B / release liner Z], was obtained in the same manner as in Example 1, except that release liner B (product name "Mat Coat #25", manufactured by Fujiko Co., Ltd.) was used instead of release liner A.

[0137] Example 3 (Production of optical semiconductor element encapsulation sheet) Example 3: A sheet for encapsulating optical semiconductor elements, consisting of [release liner C / thermosetting resin layer A1 / thermosetting resin layer B / release liner Z], was obtained in the same manner as in Example 1, except that release liner C (product name "Mat Coat #38", manufactured by Fujiko Co., Ltd.) was used instead of release liner A.

[0138] Example 4 (Production of optical semiconductor element encapsulation sheet) Example 4: A sheet for encapsulating optical semiconductor elements, consisting of [Release liner D / thermosetting resin layer A1 / thermosetting resin layer B / release liner Z], was obtained in the same manner as in Example 1, except that release liner D (product name "Releasy SC02", manufactured by Kimoto Co., Ltd.) was used instead of release liner A.

[0139] Example 5 (Preparation of Thermosetting Resin Layer A2) A resin composition solution with a solids concentration of 50% by weight was prepared by dissolving 63.9 parts by weight of an acrylic polymer (glycidyl methacrylate (GMA):ethyl acrylate (EA):butyl methacrylate (BMA) = 34% by weight:30% by weight:36% by weight, weight-average molecular weight 60,000), 34.1 parts by weight of an acrylic resin (trade name "UC-3000", a carboxyl group-containing acrylic resin, weight-average molecular weight 10,000, manufactured by Toa Gosei Co., Ltd.), 2.0 parts by weight of a silane coupling agent (trade name "KBM-303", manufactured by Shin-Etsu Chemical Co., Ltd.), and 5.1 parts by weight of an epoxy crosslinker (trade name "TETRAD-C", manufactured by Mitsubishi Gas Chemical Company, Inc.) in methyl ethyl ketone. The resin composition solution was applied to the release-treated surface of release liner B (trade name "Mat Coat #25", manufactured by Fujiko Co., Ltd.) and then dried at 130°C for 2 minutes to prepare a sheet-like thermosetting resin layer A2 with a thickness (average thickness) of 25 μm.

[0140] (Production of optical semiconductor element encapsulation sheet) Example 5 was prepared in the same manner as in Example 2, except that the thermosetting resin layer A2 was used instead of the thermosetting resin layer A1, and the sheet for encapsulating optical semiconductor elements in Example 5 consisted of [release liner B / thermosetting resin layer A2 / thermosetting resin layer B / release liner Z].

[0141] Example 6 (Production of optical semiconductor element encapsulation sheet) Example 6: A sheet for encapsulating optical semiconductor elements, consisting of [release liner C / thermosetting resin layer A2 / thermosetting resin layer B / release liner Z], was obtained in the same manner as in Example 5, except that release liner C (product name "Mat Coat #38", manufactured by Fujiko Co., Ltd.) was used instead of release liner B.

[0142] Comparative Example 1 (Production of optical semiconductor element encapsulation sheet) A sheet for encapsulating optical semiconductor elements in Comparative Example 1, consisting of [Release liner E / thermosetting resin layer A1 / thermosetting resin layer B / release liner Z], was obtained in the same manner as in Example 1, except that release liner E (product name "MRF#38", manufactured by Mitsubishi Chemical Corporation) was used instead of release liner A.

[0143] Comparative Example 2 (Production of optical semiconductor element encapsulation sheet) A sheet for encapsulating optical semiconductor elements in Comparative Example 2 was obtained in the same manner as in Example 1, except that a substrate with an antiglare layer (product name "ARC380", manufactured by Nitto Denko Corporation) was used instead of release liner A, and the sheet consisted of [substrate with antiglare layer / thermosetting resin layer A1 / thermosetting resin layer B / release liner Z].

[0144] <Evaluation> The release liners, substrates with antiglare layers, and the prepared sheets for encapsulating optical semiconductor elements used in the examples and comparative examples were evaluated as follows. The results are shown in Table 1.

[0145] (1) Arithmetic mean roughness Ra (release liner, substrate with anti-glare layer) The arithmetic mean roughness Ra of the surfaces of the release liners and antiglare layer-attached substrates used in the examples and comparative examples that come into contact with the thermosetting resin layer A1 or the thermosetting resin layer A2 was measured using a 3D measuring laser microscope (product name "LEXT OLS5000", manufactured by Olympus Corporation).

[0146] (2) Arithmetic mean roughness Ra (cured resin layer) The release liner Z was peeled off from the optical semiconductor element encapsulation sheet prepared in the Examples and Comparative Examples, and the exposed surface of the thermosetting resin layer B was attached to a black acrylic plate (45 mm wide x 50 mm long x 1 mm thick) using a hand roller without trapping air bubbles to prepare a measurement sample. The sample was then heated at 130°C and 0.5 MPa for 300 minutes to cure the thermosetting resin layer A1, the thermosetting resin layer A2, and the thermosetting resin layer B, producing an optical semiconductor device sample. The optical semiconductor device sample was then placed on a flat surface with the optical semiconductor element encapsulation sheet facing up. For the Examples and Comparative Example 1, the release liner that adhered to the cured layer (cured resin layer) of the thermosetting resin layer A1 or the thermosetting resin layer A2 was peeled off from the optical semiconductor device sample to expose the cured resin layer. The arithmetic mean roughness Ra of the exposed surface was measured using a 3D measuring laser microscope (product name "LEXT OLS5000" manufactured by Olympus Corporation). In Comparative Example 2, the substrate film with an antiglare layer was not peeled off, and the arithmetic mean roughness Ra was measured in the same manner for the surface of the substrate film with an antiglare layer of the optical semiconductor device sample.

[0147] (2) 85° gloss The optical semiconductor device samples prepared in the evaluation of the arithmetic mean roughness Ra were placed on a flat surface with the optical semiconductor element encapsulating sheet facing outward, and for Example and Comparative Example 1, the release liner was peeled off to expose the cured resin layer, and the 85° gloss of the exposed surface was measured using a glossmeter (product name "GM-268A", manufactured by Konica Minolta, Inc.) For Comparative Example 2, the 85° gloss of the surface of the substrate film with the antiglare layer of the optical semiconductor device sample was measured in the same manner.

[0148] (3) SCI Y Regarding the optical semiconductor device samples prepared in the evaluation of the arithmetic mean roughness Ra, the samples were left standing on a flat surface with the optical semiconductor element sealing sheet facing up, and the release liners were peeled off for Examples and Comparative Example 1. Then, SCI Y was measured with a spectrocolorimeter (trade name "CM-M6", manufactured by Konica Minolta Co., Ltd.) from the side of the cured resin layer or the substrate surface with an antiglare layer. The colorimeter was installed so that the measurement area was at the center of the optical semiconductor device sample and measured under the following conditions. Also, before performing the measurement with the above spectrocolorimeter, zero point calibration, white calibration, and GROSS calibration were performed according to the manufacturer's manual. <SCI Y Measurement Conditions> Measurement method: Color & Gloss Geometry: di: 8°, de: 8° Specular component included (SCI) Observation light source: D65 Observation condition: 10° field of view Measurement diameter: MAV (8 mm) Automatic average measurement: 3 times Zero calibration skip: Effective

[0149] (4) Antiglare property The optical semiconductor device samples prepared in the evaluation of the arithmetic mean roughness Ra were evaluated. The optical semiconductor device samples were left standing on a flat surface with the optical semiconductor element sealing sheet facing up. For Examples and Comparative Example 1, the release liner was peeled off to expose the cured resin layer, and the exposed surface was visually observed under a fluorescent lamp. For Comparative Example 2, the substrate surface with an antiglare layer was visually observed under a fluorescent lamp. Then, the antiglare property was evaluated based on the following evaluation criteria. <Evaluation Criteria for Antiglare Property> ◎: No reflection of fluorescent lamp ○: Reflection of fluorescent lamp, but the image looks blurred ×: Clear reflection of fluorescent lamp

[0150] (5) Color uniformity The optical semiconductor device samples prepared in the evaluation of the arithmetic mean roughness Ra were evaluated. The optical semiconductor device samples were placed on a flat surface with the optical semiconductor element encapsulating sheet facing outward, and the release liner was peeled off to expose the cured resin layer in the example and comparative example 1. The exposed surface, and the substrate surface with the antiglare layer in comparative example 2, were measured using a spectrophotometer (product name "CM-M6", manufactured by Konica Minolta, Inc.) * (SCE) and b * Specifically, the light source was fixed at a position of 45° from the measurement surface (a position where the angle of incidence of the light emitted from the light source on the measurement surface is 45°). Then, when the position where the angle of reflection of the light emitted from the light source on the measurement surface is 45° is defined as 0°, the position of the spectrophotometer was moved within a range of -15 to 110°, and a * (SCE) and b * (SCE) The maximum and minimum values ​​of each were obtained. * The difference between the maximum and minimum values ​​of (SCE) (Δa * ) and b * The difference between the maximum and minimum values ​​of (SCE) (Δb * ) was calculated and the color uniformity was evaluated based on the following evaluation criteria. Furthermore, before performing measurements with the spectrophotometer, zero-point calibration, white calibration, and GROSS calibration were performed according to the manufacturer's manual. <Evaluation criteria for color uniformity> ○:Δa * and Δb * are both less than 2 ×:Δa * and Δb * At least one of the following is 2 or more

[0151] [Table 1]

[0152] As shown in Table 1, the optical semiconductor element encapsulation sheets of the Examples were evaluated as having good antiglare properties and excellent color uniformity. On the other hand, when a release liner without an uneven surface was used (Comparative Example 1), no uneven surface was formed in the thermosetting resin layer, and the sheets were evaluated as having poor antiglare properties. Furthermore, when a substrate with an antiglare layer was used (Comparative Example 2), the sheets were evaluated as having poor color uniformity.

[0153] Variations of the invention according to the present disclosure are described below. [Appendix 1] A sheet for encapsulating one or more optical semiconductor elements arranged on a substrate, the sheet includes an encapsulating resin layer including at least a curable resin layer, a release liner having an uneven surface is attached to a surface of the encapsulating resin layer opposite to the optical semiconductor element encapsulating surface, the curable resin layer is in contact with the uneven surface of the release liner. [Appendix 2] The sheet for encapsulating an optical semiconductor element according to Appendix 1, wherein the arithmetic mean roughness Ra of the uneven surface of the release liner is 0.2 μm or more. [Appendix 3] The sheet for encapsulating an optical semiconductor element according to Appendix 1 or 2, wherein the curable resin layer has thermosetting properties. [Appendix 4] A sheet for encapsulating one or more optical semiconductor elements arranged on a substrate, the sheet includes an encapsulating resin layer including at least a cured resin layer that provides a surface opposite to the optical semiconductor element encapsulating surface, An optical semiconductor element encapsulating sheet, wherein the opposite surface of the cured resin layer is an uneven surface. [Appendix 5] The optical semiconductor element encapsulating sheet according to Appendix 4, wherein the uneven surface of the cured resin layer has an arithmetic mean roughness Ra of 0.2 μm or more. [Appendix 6] An optical semiconductor device comprising: a substrate; an optical semiconductor element disposed on the substrate; and the optical semiconductor element encapsulating sheet according to appendix 4 or 5 that encapsulates the optical semiconductor element. [Appendix 7] A step of laminating the optical semiconductor element encapsulation sheet according to any one of Appendices 1 to 3 to the optical semiconductor element provided on the substrate, thereby encapsulating the optical semiconductor element with the encapsulating resin layer; a step of forming a cured resin layer by curing the curable resin layer in a laminate obtained through the encapsulation step, the laminate including the substrate, an optical semiconductor element disposed on the substrate, and the optical semiconductor element encapsulation sheet that encapsulates the optical semiconductor element; and a step of peeling off the release liner attached to the cured resin layer to transfer the irregular surface to the cured resin layer. [Explanation of symbols]

[0154] 1. Optical semiconductor element encapsulation sheet 2 Sealing resin layer 21 Curable resin layer (A) 22 Curable resin layer (B) 2a First surface (optoelectronic semiconductor element sealing surface) 2b Second side 3,4 Release liner 4a Uneven surface 5. Substrate 6. Optical semiconductor elements 7 Cured sealing layer 71 Hardened resin layer (A) 72 Hardened resin layer (B) 10 Optical semiconductor device

Claims

1. A sheet for encapsulating one or more optical semiconductor elements arranged on a substrate, the sheet includes an encapsulating resin layer including at least a curable resin layer, a release liner having an uneven surface is attached to a surface of the encapsulating resin layer opposite to the optical semiconductor element encapsulating surface, the curable resin layer is in contact with the uneven surface of the release liner.

2. 2. The sheet for encapsulating an optical semiconductor element according to claim 1, wherein the uneven surface of the release liner has an arithmetic mean roughness Ra of 0.2 [mu]m or more.

3. The sheet for encapsulating an optical semiconductor element according to claim 1 , wherein the curable resin layer has thermosetting properties.

4. A sheet for encapsulating one or more optical semiconductor elements arranged on a substrate, the sheet includes an encapsulating resin layer including at least a cured resin layer that provides a surface opposite to the optical semiconductor element encapsulating surface, An optical semiconductor element encapsulating sheet, wherein the opposite surface of the cured resin layer is an uneven surface.

5. 5. The optical semiconductor element encapsulating sheet according to claim 4, wherein the uneven surface of the cured resin layer has an arithmetic mean roughness Ra of 0.2 μm or more.

6. An optical semiconductor device comprising: a substrate; an optical semiconductor element disposed on the substrate; and the optical semiconductor element encapsulating sheet according to claim 4 or 5 that encapsulates the optical semiconductor element.

7. a step of laminating the optical semiconductor element encapsulating sheet according to claim 1 or 2 to the optical semiconductor element provided on the substrate, thereby encapsulating the optical semiconductor element with the encapsulating resin layer; a step of forming a cured resin layer by curing the curable resin layer in a laminate obtained through the encapsulation step, the laminate including the substrate, an optical semiconductor element disposed on the substrate, and the optical semiconductor element encapsulation sheet that encapsulates the optical semiconductor element; and a step of peeling off the release liner attached to the cured resin layer to transfer the irregular surface to the cured resin layer.

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