Optical stack

Abstract

This invention provides an optical laminate with low reflectivity for incident light from the outside or with suppressed color shift. The optical laminate 1 of this invention includes a surface treatment layer 4, a substrate portion 2, and adhesive layers 3a and 3b disposed on at least one surface of the substrate portion 2. When laminated onto an optical semiconductor element 7, the substrate portion 2 is located on the optical semiconductor element 7 side relative to the surface treatment layer 4. The surface treatment layer 4 imparts anti-reflective and / or anti-glare properties to the optical laminate 1. The refractive index difference between the substrate layer in the substrate portion 2 and the layers adjacent to the substrate layer or at least one other layer included in the optical laminate 1 is 0.05 or less.

Description

[Technical Field]

[0001] This invention relates to an optical stack. More specifically, this invention relates to an optical stack used in optical semiconductor devices. [Previous Technology]

[0002] It is known that a plurality of LEDs are disposed on a substrate disposed on a backlight device used in a liquid crystal display device, a substrate disposed on a substrate disposed on an organic electroluminescent (organic EL) display device as a self-emissive display device, or a substrate disposed on a mini / μLED panel as a next-generation self-emissive display device, and the plurality of LEDs have a structure sealed by an optically laminated multilayer structure (see, for example, Patent Document 1). [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-174047 [Summary of the Invention]

[0004] [The problem the invention aims to solve]

[0005] However, when using the previous optical laminate, interlayer reflection is prone to occur between the layers, resulting in the following problems: incident light from the outside is reflected between the layers, the reflectivity increases, RGB light is refracted between the layers, the optical path length changes, and color shift occurs.

[0006] Furthermore, optical laminates sometimes use components with poor support or operability, such as polarizing plates, which are similar to optical films. To support these components, a substrate is required. However, the components used as substrates tend to have a higher refractive index compared to the components of other layers, making interlayer reflections more likely to occur. As a result, problems such as higher reflectivity, poor visibility, and color shift occur.

[0007] This invention was conceived based on the above-mentioned circumstances, and its object is to provide an optical laminate with low reflectivity for incident light from the outside or to suppress color shift. [Technical Means for Solving the Problem]

[0008] In order to achieve the above-mentioned objectives, the inventors have conducted extensive research and discovered that by controlling the refractive index difference between the substrate layer in the substrate portion constituting the above-mentioned optical laminate and the layer adjacent to the substrate layer or at least one other layer included in the above-mentioned optical laminate to 0.05 or less, the reflectivity of incident light from the outside is lower, or color shift can be suppressed. The present invention was made based on these insights.

[0009] That is, the first invention provides an optical stack comprising a surface treatment layer, a substrate portion, and an adhesive layer disposed on at least one side of the substrate portion, and is used in an optical semiconductor element. When the optical stack is bulk-deposited on the optical semiconductor element, the substrate portion is located on the optical semiconductor element side relative to the surface treatment layer. The surface treatment layer is a layer that imparts anti-reflective and / or anti-glare properties to the optical stack, and the refractive index difference between the substrate layer in the substrate portion and the layer adjacent to the substrate layer is 0.05 or less.

[0010] Furthermore, the present invention provides an optical stack comprising a surface treatment layer, a substrate portion, and an adhesive layer disposed on at least one side of the substrate portion, and is used in an optical semiconductor element. When the optical stack is bulk-deposited on the optical semiconductor element, the substrate portion is located on the optical semiconductor element side relative to the surface treatment layer. The surface treatment layer is a layer that imparts anti-reflective and / or anti-glare properties to the optical stack, and the refractive index difference between the substrate layer in the substrate portion and at least one other layer contained in the optical stack is 0.05 or less.

[0011] As described above, the first and second optical laminates of the present invention include a substrate portion in their structure. By using a raw material in which the refractive index difference between the substrate layer in the substrate portion and the layer adjacent to the substrate layer or at least one other layer included in the optical laminate is 0.05 or less, when the optical laminate is applied to an image display device, interlayer reflection between adjacent layers and / or between the substrate layer of the optical laminate and another layer other than the substrate layer can be reduced, and an image display device with reduced interlayer reflectivity or suppressed color shift can be provided.

[0012] In the first and second optical stacks of the present invention, the phase difference of the substrate layer is preferably less than 20 nm. By having this configuration, when the optical stack is applied to an image display device, an image display device with consistent appearance and improved visibility when the image is viewed from any direction can be provided.

[0013] Preferably, in the first and second optical laminates of the present invention, when the side having the substrate portion opposite to the side having the aforementioned surface treatment layer is bonded to a sheet with a surface reflectance of 40.34% and a measurement is performed, the ratio of the 45° brightness measured at an oblique angle to the front brightness measured in the vertical direction from the front [45° brightness / front brightness] is 0.95 to 1.0. With this configuration, when the aforementioned optical laminate is applied to an image display device, an image display device that is bright even when viewed at an oblique angle can be provided.

[0014] Preferably, the optical laminate of the first and second invention has a frontal reflectance of 3.2% or less when a sheet with a reflectance of 40.34% is bonded to a surface with the surface of which the surface treatment layer is the substrate layer side. With this configuration, when the optical laminate is applied to an image display device, reduced visibility due to reflection of external light or image projection can be prevented, providing an image display device with an adjusted appearance.

[0015] Furthermore, the present invention provides an optical semiconductor device comprising a substrate, an optical semiconductor element disposed on the substrate, and the aforementioned optical laminate deposited on the optical semiconductor element. In this optical semiconductor device, the reflectivity of incident light from the outside is low or color shift is suppressed.

[0016] The above-mentioned optical semiconductor device can also be a self-emissive display device. When the above-mentioned optical semiconductor device is applied to an optical semiconductor device with a display, the appearance is consistent when viewed from any direction, the visibility is improved, and light can be effectively transmitted, so it can be better used as a self-emissive display device.

[0017] Furthermore, the present invention provides an image display device comprising the above-described self-emissive display device. [Effects of the Invention]

[0018] According to the optical laminate of the present invention, the reflectivity of incident light from the outside is low, or color shift can be suppressed. Therefore, when used as an optical laminate, the appearance is consistent when viewed from any direction, visibility is improved, and light can be effectively transmitted. Furthermore, when applied to an optical semiconductor device with a display, it can be used more efficiently with a lower light intensity than before, thus enabling the manufacture of products with excellent economic efficiency.

Implementation Method

[0020] [Optical Stack] The optical stack of the present invention comprises at least a surface treatment layer, a substrate portion, and an adhesive layer disposed on at least one side of the substrate portion. The optical stack system of the present invention is stacked in an optical semiconductor device for use.

[0021] When the optical stack is applied to the optical semiconductor element, the substrate portion is located on the optical semiconductor element side relative to the surface treatment layer. That is, when the optical stack is applied to the optical semiconductor element, a structure is adopted in which the surface treatment layer, the substrate portion, and the optical semiconductor element are sequentially stacked.

[0022] Examples of the laminated structure of the surface treatment layer, adhesive layer, and substrate portion in the above-described optical laminate include [surface treatment layer / substrate portion / adhesive layer], [surface treatment layer / adhesive layer / substrate portion], and [surface treatment layer / adhesive layer / substrate portion / adhesive layer]. Preferably, the above-described optical laminate has a structure in which the above-described surface treatment layer, the above-described substrate portion, and the above-described adhesive layer are sequentially laminated.

[0023] In addition to the surface treatment layer, the substrate portion, and the adhesive layer described above, the optical laminate of the present invention may also include a release liner. The release liner is, for example, attached to the adhesive layer located on the surface of the optical laminate and peeled off when the optical laminate is used. Furthermore, it is not necessary to provide a release liner.

[0024] Furthermore, the optical laminate of the present invention may also have a surface protective film on the surface of the optical laminate (e.g., the surface of the surface treatment layer). This can protect the surface of the optical laminate (e.g., the surface of the surface treatment layer) before use. Moreover, it is not necessary to provide a surface protective film.

[0025] Hereinafter, one embodiment of the optical stack of the present invention will be described. FIG1 is a cross-sectional view showing one embodiment of the optical stack of the present invention. As shown in FIG1, the optical stack 1 can be used to stack one or more optical semiconductor elements disposed on a substrate, and includes a substrate portion 2, an adhesive layer 3, a surface treatment layer 4, and a release liner 5. The adhesive layer 3 includes an adhesive layer 3a and another adhesive layer 3b disposed on both sides of the substrate portion 2. The adhesive layer (the adhesive layer stacked on the side of the optical semiconductor element) 3a includes a first adhesive layer 31 and a second adhesive layer 32. The other adhesive layer 3b is used to bond the substrate portion 2 and the surface treatment layer 4, and includes a third adhesive layer 33. The surface treatment layer 4 is disposed on the other side of the substrate portion 2 and on the surface of the optical stack 1. The release liner 5 is attached to the adhesive layer 3, specifically, to the surface of the second adhesive layer 32 (the surface opposite to the side having the substrate portion 2). In other words, the optical laminate 1 sequentially comprises a surface treatment layer 4, a substrate portion 2, an adhesive layer 3, and a release liner 5.

[0026] (Substrate Section) The aforementioned substrate section serves as a support in the aforementioned optical laminate, thereby improving the operability of the aforementioned optical laminate. The aforementioned substrate section can be a single layer, or it can be multiple identical layers or multiple layers with different compositions or thicknesses. When the aforementioned substrate section includes multiple substrate layers, each layer can be bonded together by other layers such as an adhesive layer, or the substrate layers can be directly bonded to each other. Furthermore, the substrate layer used in the substrate section is the portion of the optical laminate volume layer that is bonded together with the adhesive layer to the substrate containing the optical semiconductor element when the optical semiconductor element is applied. The release liner that is peeled off during the use of the optical laminate (during attachment) or the surface protective film used only to protect the surface of the substrate section is not included in the "substrate section".

[0027] The refractive index difference between the substrate layer in the above-described substrate portion and the layer adjacent to the substrate layer is preferably 0.05 or less, more preferably 0.04 or less, and even more preferably 0.03 or less. If the refractive index difference between the substrate layer and the layer adjacent to the substrate layer is 0.05 or less, reflection at the interface can be reduced, resulting in excellent visibility of the optical semiconductor device and reducing the likelihood of color shift. Furthermore, when the above-described substrate portion includes a plurality of substrate layers, it is sufficient that the refractive index difference between at least one of the plurality of substrate layers and the layer adjacent to that substrate layer is within the above-described range. Moreover, it is preferable that the refractive index difference between at least one of the two layers adjacent to the substrate layer and the substrate layer is within the above-described range, and even more preferably that the refractive index difference between both layers and the substrate layer is within the above-described range. Furthermore, in this specification, the substrate layer that will sometimes be used as the comparison object for the above-described refractive index difference is referred to as "substrate layer (A)". Furthermore, examples of layers adjacent to the aforementioned substrate layer (A) include the aforementioned surface treatment layer, the aforementioned adhesive layer, substrate layers other than the aforementioned substrate layer (A), and adhesive layers that bond the substrate layers together. Moreover, the refractive index of the adjacent layers is a value under the operating conditions of the optical laminate, and when the adjacent layers are hardenable layers (hardenable layers) such as hardenable adhesive layers, it is a value under the condition that the hardenable layer has hardened.

[0028] The refractive index difference between the substrate layer (substrate layer (A)) in the aforementioned substrate portion and one of the layers (other layers) included in the aforementioned optical stack, excluding the substrate layer (substrate layer (A)), is preferably 0.05 or less, more preferably 0.04 or less, and even more preferably 0.03 or less. If the refractive index difference between the substrate layer (A) and one of the other layers is 0.05 or less, interlayer reflection caused by the optical stack as a whole can be reduced, resulting in excellent visibility of the optical semiconductor device and less color shift. Furthermore, when the aforementioned substrate portion includes a plurality of substrate layers, it is sufficient that the refractive index difference between at least one of the plurality of substrate layers and the other layers is within the aforementioned range. Moreover, it is preferable that the refractive index difference between the substrate layer and all other layers included in the aforementioned optical stack is within the aforementioned range. Furthermore, the layers included in the aforementioned optical laminate may include, for example, the aforementioned surface treatment layer, the aforementioned adhesive layer, a substrate layer other than the aforementioned substrate layer (A), and an adhesive layer for attaching the substrate layers to each other. Moreover, the refractive index of the aforementioned other layers is a value under the operating conditions of the optical laminate, and when the aforementioned other layers are hardening layers (hardening layers) such as hardening adhesive layers, it is a value under the condition that the hardening layer has hardened.

[0029] The refractive index of the substrate layer (A) is preferably 1.43 to 1.55, and more preferably 1.48 to 1.53. By having the refractive index of the substrate layer (A) within the aforementioned range, there is a tendency to reduce the refractive index difference with other layers constituting the optical laminate (e.g., the aforementioned surface treatment layer or the aforementioned adhesive layer), thereby reducing reflectivity at the interface, improving the visibility of the optical semiconductor device, and reducing the likelihood of color shift. Furthermore, when the substrate portion comprises a plurality of substrate layers, it is sufficient that the refractive index of at least one of the plurality of substrate layers is within the aforementioned range; more preferably, the refractive indices of all of the plurality of substrate layers are within the aforementioned range.

[0030] The phase difference of the aforementioned substrate layer (A) is preferably 20 nm or less, more preferably 15 nm or less, and even more preferably 10 nm or less. When a substrate layer with a large phase difference is used, there is a tendency for iris-like unevenness to be perceived when polarized light passes through due to multiple reflections. In contrast, if the phase difference of the aforementioned substrate portion is 20 nm or less (especially 10 nm or less), the generation of iris-like unevenness is suppressed even when polarized light passes through, and the appearance can be made consistent when applied to an image display device.

[0031] Preferably, the substrate portion has a substrate layer with a biomass content of at least 30%. When the substrate portion comprises a plurality of substrate layers, the plurality of substrate layers may consist only of a substrate layer with a biomass content of at least 30%, or may include a substrate layer with a biomass content of at least 30% and other substrate layers.

[0032] By using a substrate layer with a biomass content of 30% or more as the substrate, the aforementioned optical laminate is environmentally friendly. The biomass content of the substrate layer with a biomass content of 30% or more is calculated as the mass ratio of the biomass-derived components to the total amount (100% by mass) of the resin components constituting the substrate layer with a biomass content of 30% or more.

[0033] The tensile modulus of the substrate layer (A) is preferably 1.5 to 3.5 GPa, more preferably 2 to 3.3 GPa. If the tensile modulus is 1.5 GPa or higher, the substrate portion has appropriate hardness, and when the optical multilayer is bonded to the optical semiconductor element, the shape of the optical semiconductor element is not easily visible on the surface, and the surface smoothness is excellent. If the tensile modulus is 3.5 GPa or lower, the substrate portion has appropriate flexibility, and when the optical semiconductor element is provided as a convex portion and the gap between the plurality of optical semiconductor elements is provided as a concave portion, the optical multilayer has excellent conformability to the convex and concave portions, and the embedding of the optical semiconductor element is excellent.

[0034] The elongation at break of the substrate layer (A) is preferably 2% or more, more preferably 2.5% or more, and even more preferably 3% or more. If the elongation at break is 2% or more, the optical laminate exhibits excellent conformability to the unevenness formed by the optical semiconductor element, and the embedding capability of the optical semiconductor element is even better. The elongation at break is, for example, 100% or less.

[0035] Examples of substrate layers constituting the above-mentioned substrate portion (the above-mentioned substrate layer (A) and the above-mentioned other substrate layers) include glass or plastic substrates (especially plastic films). Examples of resins constituting the above-mentioned plastic substrates include: low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolymer polypropylene, polybutene, polymethylpentene, ionomers, ethylene-(meth)acrylate copolymers, ethylene-(meth)acrylate (random, alternating) copolymers, ethylene-vinyl acetate copolymers, ethylene-propylene copolymers, cyclic olefin polymers, ethylene-butene copolymers, and ethylene... Polyolefin resins such as hexene copolymers; polyurethanes; polyesters such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonates; polyimide resins; polyetheretherketones; polyetherimides; aromatic polyamines and fully aromatic polyamines; polyphenylene sulfide; fluoropolymers; polyvinyl chloride; polyvinylidene chloride; cellulose resins such as triacetin (TAC); silicone resins; acrylic resins such as polymethyl methacrylate; polyurethane; polyarylates; polyvinyl acetate, etc. Only one of the above resins may be used, or two or more may be used.

[0036] Preferably, the substrate layer (A) is a layer containing a polycarbonate resin, i.e., a polycarbonate substrate. If the substrate layer (A) is a polycarbonate substrate, the rigidity of the substrate portion is higher, and the operability of the optical laminate is more excellent.

[0037] Examples of the above-mentioned polycarbonate resins include those obtained by the phosgene method, which involves reacting a dihydroxy compound with phosgene, or by the transesterification method, which involves reacting a dihydroxy compound with carbonates such as diphenyl carbonate. Only one type of polycarbonate resin may be used, or two or more types may be used.

[0038] The aforementioned dihydroxy compound can be exemplified as a known or commonly used dihydroxy compound constituting a polycarbonate resin. When the aforementioned substrate layer (A) is a polycarbonate substrate, the polycarbonate resin constituting the polycarbonate substrate preferably has isosorbide structural units as structural units derived from the aforementioned dihydroxy compound. Furthermore, compared to conventional polycarbonate resins using dihydroxy diaryl compounds, it exhibits superior UV resistance. Moreover, due to its amorphous tendency, it exhibits superior surface conformability compared to crystalline resins such as PET.

[0039] The above-mentioned dihydroxy compounds may also include other dihydroxy compounds besides isosorbide. Examples of such other dihydroxy compounds include dihydroxy diaryl compounds, dihydroxy alicyclic hydrocarbon compounds, and other dihydroxy compounds having a cyclic skeleton.

[0040] Among the other dihydroxy compounds mentioned above, dihydroxy alicyclic hydrocarbon compounds are preferred, and tricyclic [5.2.1.02,6]decanediethanol is even more preferred.

[0041] The thickness of the substrate layer (A) is preferably 5 to 300 μm, more preferably 20 to 150 μm. If the thickness is 5 μm or more, the support and operability of the optical laminate are further improved. If the thickness is 300 μm or less, the thickness of the optical semi-laminated layer can be thinner, and the optical semiconductor device can be thinner.

[0042] To improve adhesion and retention with the adhesive layer, physical treatments such as corona discharge treatment, plasma treatment, sanding treatment, ozone exposure treatment, flame exposure treatment, high voltage electric shock exposure treatment, and ionization radiation treatment can be applied to the surface of the substrate portion on the side having the adhesive layer; chemical treatments such as chromic acid treatment; and easy-bonding treatments using a coating agent (primer). The surface treatment used to improve adhesion is preferably applied to the entire surface of the substrate portion on the adhesive layer side.

[0043] From the viewpoint of excellent function as a support and excellent scratch resistance of the surface, the thickness of the substrate portion is preferably 5 μm or more, and more preferably 10 μm or more. From the viewpoint of even better transparency, the thickness of the substrate portion is preferably 300 μm or less, and more preferably 200 μm or less.

[0044] (Adhesive layer) The adhesive layer is disposed on at least one side of the substrate portion. When the adhesive layer is disposed on both sides of the substrate portion, the adhesive layers on both sides may be the same, or they may be adhesive layers with different compositions or thicknesses. Furthermore, the adhesive layers disposed on at least one side of the substrate portion may each be a single layer, or they may be multiple layers with different compositions or thicknesses.

[0045] Preferably, the adhesive layer is provided at least on the side opposite to the substrate portion where it is laminated with the optical semiconductor element (i.e., the side with the surface treatment layer). With this structure, the adhesive layer can be used to adhere to the optical semiconductor element. Furthermore, by directly adhering the adhesive layer to the optical semiconductor element, the optical semiconductor element can be sealed using the adhesive layer.

[0046] Alternatively, the adhesive layer may be provided on the side of the substrate having the surface treatment layer (i.e., the side opposite to the side of the optical semiconductor device stack). When the surface treatment layer is a surface treatment stack body described later, the substrate and the surface treatment stack body can be bonded together via the adhesive layer.

[0047] The adhesive constituting the adhesive layer is not particularly limited, and examples include acrylic adhesives, rubber adhesives (natural rubber, synthetic rubber, and mixtures thereof), silicone adhesives, polyester adhesives, urethane adhesives, polyether adhesives, polyamide adhesives, and fluorinated adhesives. Among these, acrylic adhesives are preferred in terms of superior transparency, adhesion, weather resistance, cost, and ease of adhesive design. The adhesive layer is preferably an acrylic adhesive layer containing an acrylic adhesive. Only one type of adhesive may be used, or two or more types may be used.

[0048] When the adhesive layer is composed of multiple layers on the side of the substrate portion where the optical laminate is formed, the adhesive layer preferably includes a curable adhesive layer (curable adhesive layer) and a non-curable adhesive layer (non-curable adhesive layer).

[0049] (Curing Adhesive Layer) Examples of the aforementioned curing adhesive layer include an adhesive layer that cures upon exposure to radiation (radiation-curing adhesive layer) and an adhesive layer that cures upon exposure to heat (thermo-curing adhesive layer). Examples of radiation include active energy rays such as electron beams, ultraviolet light, alpha rays, beta rays, gamma rays, and X-rays. Ultraviolet light is preferred.

[0050] Preferably, the aforementioned radiation-curing adhesive layer comprises a polymer having radiation-polymerizing functional groups as the base polymer (i.e., the polymer with the highest content). The content of the aforementioned polymer having radiation-polymerizing functional groups in the radiation-curing adhesive layer is preferably 50% by mass or more (e.g., 50-100% by mass) relative to 100% of the total weight of the radiation-curing adhesive layer, more preferably 80% by mass or more (e.g., 80-100% by mass), and even more preferably 90% by mass or more (e.g., 90-100% by mass). If the content is 50% by mass or more, the curing properties of the radiation-curing adhesive layer are more excellent, and the lateral adhesion is further reduced due to radiation irradiation. Furthermore, the transparency of the sheet for sealing optical semiconductor devices is further improved.

[0051] Examples of the aforementioned radiopolymerizable functional groups include radioradical polymerizable groups such as vinyl unsaturated groups containing carbon-carbon unsaturated bonds, or radiocationic polymerizable groups. Examples of groups containing carbon-carbon unsaturated bonds include vinyl, propenyl, isopropenyl, acrylamide, and methacrylamide. Examples of the aforementioned radiocationic polymerizable groups include epoxy, cyclohexaoxybutyl, and oxacyclopentyl. Preferably, the group contains carbon-carbon unsaturated bonds, and more preferably, acrylamide or methacrylamide. Only one type of radiopolymerizable functional group may be used, or two or more types may be used. The position of the aforementioned radiopolymerizable functional group may be any one of the polymer side chain, in the polymer backbone, or at the end of the polymer backbone.

[0052] The polymer having the above-mentioned radiopolymerizable functional group can be produced, for example, by reacting a polymer having a reactive functional group (first functional group) with a compound having a functional group (second functional group) that can react with the first functional group to form a bond and the above-mentioned radiopolymerizable functional group, while maintaining the radiopolymerizability of the above-mentioned radiopolymerizable functional group. Therefore, the polymer having the above-mentioned radiopolymerizable functional group preferably comprises a structural portion from the polymer having the first functional group and a structural portion from the compound having the second functional group and the radiopolymerizable functional group.

[0053] Examples of combinations of the first functional group and the second functional group mentioned above include carboxyl and epoxy, epoxy and carboxyl, carboxyl and aziridinyl, aziridinyl and carboxyl, hydroxyl and isocyanate, and isocyanate and hydroxyl. Among these, the combination of hydroxyl and isocyanate, and the combination of isocyanate and hydroxyl are preferred from the viewpoint of ease of reaction tracking. Only one of the above combinations may be used, or two or more may be used.

[0054] Polymers having the above-mentioned radiopolymerizable functional groups, i.e., polymers having the above-mentioned first functional group, include, for example, acrylic polymers, urethane acrylate resins, epoxy resins, epoxy acrylate resins, oxetane resins, silicone resins, silicone acrylate resins, polyester resins, etc. Among these, acrylic polymers are preferred. Only one of the above polymers may be used, or two or more may be used.

[0055] The above-mentioned acrylic polymer is a polymer in which structural units derived from acrylic monomers (monomers having (meth)acrylic groups in their molecules) serve as the structural units of the polymer. Only one type of acrylic polymer may be used, or two or more types may be used.

[0056] Preferably, the above-mentioned acrylic polymer is a polymer containing, by mass ratio, the most structural units derived from (meth)acrylate.

[0057] Examples of the above-mentioned (meth)acrylates include (meth)acrylates containing hydrocarbon groups that may have alkoxy groups. Examples of the hydrocarbon-containing (meth)acrylates containing hydrocarbon groups that may have alkoxy groups include alkyl (meth)acrylates with linear or branched aliphatic hydrocarbon groups, cycloalkyl (meth)acrylates, and other (meth)acrylates with alicyclic hydrocarbon groups, as well as aromatic (meth)acrylates, etc. Only one type of the above-mentioned hydrocarbon-containing (meth)acrylates containing alkoxy groups may be used, or two or more types may be used.

[0058] Examples of the above-mentioned alkyl methacrylates include: methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, dibutyl methacrylate, terbutyl methacrylate, amyl methacrylate, isoamyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, and isooctyl methacrylate. Nonyl methacrylate, isononyl methacrylate, decyl methacrylate, isodecyl methacrylate, undecyl methacrylate, dodecyl methacrylate (lauryl methacrylate), tridecyl methacrylate, tetradecyl methacrylate, pentadecyl methacrylate, hexadecyl methacrylate, heptadecanyl methacrylate, octadecyl methacrylate, nonadecanyl methacrylate, eicosyl methacrylate, etc.

[0059] Among the above-mentioned alkyl (meth)acrylates, it is preferable to be an alkyl (meth)acrylate having a straight-chain or branched aliphatic hydrocarbon group having 1 to 20 carbon atoms (preferably 1 to 14, more preferably 2 to 10, and even more preferably 2 to 8). If the number of carbon atoms is within the above range, the glass transition temperature of the acrylic polymer can be easily adjusted, making it easier to make the adhesion of the radiation-curing adhesive layer more suitable.

[0060] Examples of the above-mentioned (meth)acrylates having an alicyclic hydrocarbon group include: cyclopentyl methacrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, cyclooctyl methacrylate, etc., which have a monocyclic aliphatic hydrocarbon ring; isocyanate methacrylate, etc., which have a bicyclic aliphatic hydrocarbon ring; dicyclopentyl methacrylate, dicyclopentoxyethyl methacrylate, tricyclopentyl methacrylate, 1-adamantyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-adamantyl methacrylate, etc., which have three or more aliphatic hydrocarbon rings. Preferably, the (meth)acrylate has a monocyclic aliphatic hydrocarbon ring, and more preferably, cyclohexyl methacrylate.

[0061] Examples of the above-mentioned (meth)acrylates having aromatic hydrocarbon groups include phenyl (meth)acrylate, benzyl (meth)acrylate, etc.

[0062] The hydrocarbon-containing (meth)acrylates having an alkoxy group can be exemplified by those in which one or more hydrogen atoms in the hydrocarbon group of the above-mentioned hydrocarbon-containing (meth)acrylates are substituted with an alkoxy group, such as 2-methoxymethyl ester, 2-methoxyethyl ester, 2-methoxybutyl ester, etc.

[0063] Among the above-mentioned (meth)acrylates containing alkoxy groups, alkyl (meth)acrylates containing aliphatic hydrocarbon groups with straight or branched chains are preferred, and even more preferably (meth)acrylates containing alicyclic hydrocarbon groups. In this case, the adhesiveness of the radiation-curing adhesive layer is well balanced, and the sealing performance of the optoelectronic semiconductor device is even better.

[0064] In order for the radiation-curing adhesive layer to appropriately exhibit the basic properties such as adhesion or close contact with optical semiconductor elements brought about by the aforementioned alkoxy-containing hydrocarbon-containing (meth)acrylate, the ratio of the aforementioned alkoxy-containing hydrocarbon-containing (meth)acrylate to the total amount of the aforementioned total monomer components (100 mol%) is preferably 40 mol% or more, more preferably 50 mol% or more. Furthermore, from the viewpoint of being able to copolymerize with other monomer components and obtain the effects of those other monomer components, the aforementioned ratio is preferably 95 mol% or less, more preferably 80 mol% or less.

[0065] The ratio of alkyl (meth)acrylates having linear or branched aliphatic hydrocarbon groups in the total monomer components constituting the acrylic polymer having the above-mentioned first functional group is preferably 30 mol% or more, more preferably 40 mol% or more, relative to the total amount (100 mol%) of the above-mentioned total monomer components. Furthermore, the above ratio is preferably 90 mol% or less, more preferably 70 mol% or less.

[0066] The ratio of (meth)acrylates having alicyclic hydrocarbon groups in the total monomer components constituting the acrylic polymer having the above-mentioned first functional group is preferably 1 mol% or more, and more preferably 5 mol% or more, relative to the total amount of the above-mentioned total monomer components (100 mol%). Furthermore, the above ratio is preferably 30 mol% or less, and more preferably 20 mol% or less.

[0067] For the purpose of introducing the first functional group or modifying cohesion, heat resistance, etc., the acrylic polymer may also include structural units from other monomer components that can copolymerize with the aforementioned (meth)acrylate containing a hydrocarbon group that may have an alkoxy group. Examples of such other monomer components include carboxyl-containing monomers, acid anhydride monomers, hydroxyl-containing monomers, glycidyl-containing monomers, sulfonic acid-containing monomers, phosphate-containing monomers, nitrogen-containing monomers, and other polar monomers. Only one of these other monomer components may be used, or two or more may be used.

[0068] Examples of the above-mentioned carboxyl-containing monomers include acrylic acid, methacrylic acid, carboxyethyl methacrylate, carboxypentyl methacrylate, itconic acid, maleic acid, fumaric acid, and butenoic acid. Examples of the above-mentioned acid anhydride monomers include maleic anhydride and itconic anhydride.

[0069] Examples of the above-mentioned hydroxyl-containing monomers include: 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl methacrylate, 8-hydroxyoctyl methacrylate, 10-hydroxydecyl methacrylate, 12-hydroxylaurate methacrylate, and methyl methacrylate (4-hydroxymethylcyclohexyl)

[0070] Examples of the above-mentioned monomers containing glycidyl groups include glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, etc.

[0071] Examples of the above-mentioned sulfonic acid-containing monomers include styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamide propanesulfonic acid, (meth)acrylate sulfonyl ester, (meth)acryloxynaphthalene sulfonic acid, etc.

[0072] Examples of the above-mentioned phosphate-containing monomers include 2-hydroxyethylpropenyl phosphate, etc.

[0073] Examples of the above-mentioned nitrogen-containing monomers include morpholino monomers such as (meth)acrylamide, cyano monomers such as (meth)acrylonitrile, and acrylamide monomers such as (meth)acrylamide.

[0074] Preferably, the acrylic polymer contains a hydroxyl-containing monomer as the polar monomer constituting the above-mentioned acrylic polymer. By using a hydroxyl-containing monomer, the first functional group can be easily introduced. Furthermore, the acrylic polymer and the radiation-curing adhesive layer have excellent water resistance, and even when the sheet for sealing optical semiconductor devices is used in a high humidity environment, it is not easy to produce white haze, and it has excellent anti-whitening properties.

[0075] The hydroxyl-containing monomers mentioned above are preferably 2-hydroxyethyl methacrylate and 4-hydroxybutyl methacrylate, and more preferably 2-hydroxyethyl methacrylate.

[0076] In order to properly exhibit the basic properties such as adhesion or close contact with optical semiconductor devices brought about by the aforementioned alkoxy-containing hydrocarbon (meth)acrylate, the proportion of the polar monomer in the total monomer composition (100 mol%) of the acrylic polymer having the aforementioned first functional group is preferably 5 to 50 mol%, more preferably 10 to 40 mol%. In particular, from the viewpoint that the water resistance of the radiation-curing adhesive layer is also superior, the proportion of hydroxyl monomer is preferably within the above range.

[0077] In order to form a cross-linked structure in its polymer backbone, the aforementioned acrylic polymer may also contain structural units derived from polyfunctional (meth)acrylates that can copolymerize with the monomer components constituting the acrylic polymer. Examples of such polyfunctional (meth)acrylates include: hexanediol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, neopentyl glycol dimethacrylate, pentaerythritol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, dipentaerythritol hexamethacrylate, etc. Only one of the aforementioned polyfunctional (meth)acrylates may be used, or two or more may be used.

[0078] In order to properly exhibit the basic properties such as adhesion or close contact with optical semiconductor devices brought about by the above-mentioned (meth)acrylate containing hydrocarbon groups that may have alkoxy groups, the ratio of the above-mentioned polyfunctional (meth)acrylate in the total monomer composition (100 mol%) of the acrylic polymer having the above-mentioned first functional group is preferably 40 mol% or less, and more preferably 30 mol% or less.

[0079] The technology for producing polymers with highly reactive isocyanate groups is quite difficult. On the other hand, from the viewpoint of ease of production and acquisition of acrylic polymers with hydroxyl groups, the combination of the first functional group and the second functional group is preferably a combination of the first functional group being a hydroxyl group and the second functional group being an isocyanate group.

[0080] Examples of compounds having the above-mentioned radioactive polymerizable functional groups and isocyanate groups include: methacrylic isocyanate, 2-acrylic oxyethyl isocyanate, 2-methacrylic oxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, etc. Only one of the above compounds may be used, or two or more may be used.

[0081] From the viewpoint of further promoting the curing of the radiation-curing adhesive layer, in the acrylic polymer having the aforementioned radiation-polymerizing functional group, the content of the structural portion from the compound having the aforementioned second functional group and the radiation-polymerizing functional group is preferably 0.5 mol or more, more preferably 1 mol or more, and further preferably 3 mol or more, and further preferably 10 mol or more, relative to the total amount of the structural portion from the acrylic polymer having the aforementioned first functional group (100 mol). The aforementioned content is, for example, 100 mol or less.

[0082] From the viewpoint of further promoting the curing of the radiation-curing adhesive layer, in the acrylic polymer having the aforementioned radiopolymerizable functional group, the molar ratio of the second functional group to the first functional group [second functional group / first functional group] is preferably 0.01 or more, more preferably 0.05 or more, further preferably 0.2 or more, and even more preferably 0.4 or more. Furthermore, from the viewpoint of further reducing low molecular weight substances in the radiation-curing adhesive layer, the aforementioned molar ratio is preferably less than 1.0, and more preferably 0.9 or less.

[0083] An acrylic polymer having the above-mentioned radiopolymerizable functional group can be produced, for example, by polymerizing (copolymerizing) a raw material monomer containing a monomer component having the first functional group to obtain an acrylic polymer having the first functional group, and then subjecting a compound having the above-mentioned second functional group and radiopolymerizable functional group to a condensation reaction or addition reaction with the acrylic polymer while maintaining the radiopolymerizable nature of the radiopolymerizable functional group.

[0084] The acrylic polymer having the aforementioned first functional group is obtained by polymerizing the various monomer components described above. The polymerization method is not particularly limited; examples include solution polymerization, emulsion polymerization, bulk polymerization, and polymerization using active energy lines (active energy line polymerization). Furthermore, the obtained acrylic polymer can be any of a random copolymer, block copolymer, or graft copolymer.

[0085] Various common solvents can also be used when polymerizing monomer components. Examples of such solvents include: esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and ketones such as methyl ethyl ketone and methyl isobutyl ketone. Only one of the above solvents may be used, or two or more may be used.

[0086] There are no particular limitations on the polymerization initiators, chain transfer agents, emulsifiers, etc. used in the free radical polymerization of monomer components, and they can be selected and used appropriately. Furthermore, the weight average molecular weight of acrylic polymers can be controlled by the amount of polymerization initiators and chain transfer agents used and the reaction conditions, and their usage can be adjusted appropriately according to their types.

[0087] The polymerization initiator used for the polymerization of monomer components may be a thermal polymerization initiator or a photopolymerization initiator (photoinitiator), depending on the type of polymerization reaction. Only one of the above polymerization initiators may be used, or two or more may be used.

[0088] The above-mentioned thermal polymerization initiator is not particularly limited, and examples include azo polymerization initiators, peroxide polymerization initiators, and redox polymerization initiators. The amount of the above-mentioned thermal polymerization initiator used is preferably 1% by mass or less, more preferably 0.005 to 1% by mass, and even more preferably 0.02 to 0.5% by mass, relative to 100% of the total monomer components constituting the acrylic polymer having the above-mentioned first functional group.

[0089] Examples of the aforementioned photopolymerization initiators include: benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-keto alcohol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzoyl ether-based photopolymerization initiators, ketal-based photopolymerization initiators, 9-oxosulfuron-based photopolymerization initiators, phosphonium oxychloride-based photopolymerization initiators, and titanium dioxide-based photopolymerization initiators. Among these, acetophenone-based photopolymerization initiators are preferred.

[0090] Examples of the above-mentioned acetophenone-based photopolymerization initiators include: 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, 4-(tert-butyl)dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, methoxyacetophenone, etc.

[0091] The amount of the above-mentioned photopolymerization initiator used is preferably 0.005 to 1% by mass relative to 100% of the total monomer components constituting the acrylic polymer having the above-mentioned first functional group, more preferably 0.01 to 0.7% by mass, and even more preferably 0.18 to 0.5% by mass. If the above-mentioned amount used is 0.005% by mass or more (especially 0.18% by mass or more), it is easier to control the molecular weight of the acrylic polymer to be smaller, and there is a tendency for the residual stress of the radiation-curing adhesive layer to be higher and the step absorption to be better.

[0092] The reaction of the acrylic polymer having the first functional group described above with a compound having the second functional group and a radiopolymerizable functional group described above can be carried out, for example, in a solvent under stirring in the presence of a catalyst. Examples of such solvents are those described above. The catalyst is appropriately selected based on the combination of the first and second functional groups. The reaction temperature in the above reaction is, for example, 5–100°C, and the reaction time is, for example, 1–36 hours.

[0093] Acrylic polymers having the aforementioned radiopolymerizable functional groups may also have structural portions derived from crosslinking agents. For example, crosslinking of the aforementioned acrylic polymers can further reduce low molecular weight substances in the radiopolymerizable adhesive layer. Furthermore, the weight average molecular weight of the acrylic polymer can be increased. Moreover, the aforementioned crosslinking agent is one that crosslinks functional groups other than the radiopolymerizable functional groups with each other (e.g., first functional groups with each other, second functional groups with each other, or first functional groups and second functional groups). Only one type of crosslinking agent may be used, or two or more types may be used.

[0094] Examples of the aforementioned crosslinking agents include: isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, aziridine-based crosslinking agents, amine-based crosslinking agents, silicone-based crosslinking agents, and silane-based crosslinking agents. Among the aforementioned crosslinking agents, from the viewpoints of excellent adhesion to optical semiconductor devices and fewer impurity ions, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred, and isocyanate-based crosslinking agents are even more preferred.

[0095] Examples of the above-mentioned isocyanate-based crosslinking agents (polyfunctional isocyanate compounds) include: lower aliphatic polyisocyanates such as 1,2-ethylenyl diisocyanate, 1,4-butylenyl diisocyanate, and 1,6-hexamethylene diisocyanate; alicyclic polyisocyanates such as cyclopentyl diisocyanate, cyclohexyl diisocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, and hydrogenated xylene diisocyanate; and aromatic polyisocyanates such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and phenyl dimethyl diisocyanate. Furthermore, examples of the above-mentioned isocyanate-based crosslinking agents include trimethylolpropane / toluene diisocyanate adducts, trimethylolpropane / hexamethylene diisocyanate adducts, and trimethylolpropane / phenyl dimethyl diisocyanate adducts.

[0096] The content of the structural portion of the crosslinking agent is not particularly limited. It is preferable to contain 5% or less of the total amount of the acrylic polymer having the radiopolymerizable functional group other than the structural portion of the crosslinking agent, which is 100% by mass. More preferably, it is 0.001 to 5% by mass, and even more preferably, it is 0.01 to 3% by mass.

[0097] The aforementioned radiation-curing adhesive layer may also contain other components besides the polymer having the aforementioned radiation-polymerizing functional groups, within the scope that does not impair the effects of the present invention. Examples of such other components include: crosslinking accelerators, adhesion-improving resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), oligomers, anti-aging agents, fillers (metal powders, organic fillers, inorganic fillers, etc.), antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, granules, foils, etc. Only one of the aforementioned other components may be used, or two or more may be used.

[0098] (Non-curing adhesive layer) The adhesive forming the above-mentioned non-curing radiation adhesive layer may be a known or conventional pressure-sensitive adhesive that does not have radiation-curing properties, i.e., does not contain compounds with radiation-curing properties. However, it may contain a small amount of unavoidable compounds with radiation-curing properties that migrate from other layers of the stack. Examples of such adhesives include: acrylic adhesives, rubber adhesives (natural rubber, synthetic rubber, and mixtures thereof), silicone adhesives, polyester adhesives, urethane adhesives, polyether adhesives, polyamide adhesives, and fluorinated adhesives. Among these, acrylic adhesives are preferred for constituting the non-curing radiation adhesive layer in terms of adhesion, weather resistance, cost, and ease of adhesive design. The aforementioned non-curing radiation adhesive layer is preferably an acrylic adhesive layer containing an acrylic adhesive. Only one type of adhesive may be used, or two or more types may be used.

[0099] The aforementioned acrylic adhesive layer contains an acrylic polymer as a base polymer. The aforementioned acrylic polymer is a polymer that includes acrylic monomers as monomeric components constituting the polymer. That is, the aforementioned acrylic polymer contains structural units derived from acrylic monomers. Furthermore, only one type of acrylic polymer may be used, or two or more types may be used.

[0100] The content of the acrylic polymer in the acrylic adhesive layer is not particularly limited, but it is preferably 50% by mass or more (e.g., 50 to 100% by mass) relative to the total amount of the adhesive layer, more preferably 80% by mass or more (e.g., 80 to 100% by mass), and even more preferably 90% by mass or more (e.g., 90 to 100% by mass). If the content is 50% by mass or more, the transparency of the sheet for sealing optical semiconductor devices is even better.

[0101] Preferably, the above-mentioned acrylic polymer is a polymer formed by using (meth)acrylate as an essential monomer component. That is, the above-mentioned acrylic polymer preferably contains (meth)acrylate as a structural unit.

[0102] Examples of the above-mentioned (meth)acrylates include (meth)acrylates containing hydrocarbon groups that may have alkoxy groups. Examples of the hydrocarbon-containing (meth)acrylates among the above-mentioned (meth)acrylates containing hydrocarbon groups that may have alkoxy groups include alkyl (meth)acrylates having linear or branched aliphatic hydrocarbon groups, (meth)acrylates having alicyclic hydrocarbon groups, and (meth)acrylates having aromatic hydrocarbon groups. Only one type of the above-mentioned (meth)acrylates containing hydrocarbon groups that may have alkoxy groups may be used, or two or more types may be used.

[0103] Among the above-mentioned alkyl (meth)acrylates, it is preferable to be an alkyl (meth)acrylate having a straight-chain or branched aliphatic hydrocarbon group having 1 to 20 carbon atoms (preferably 1 to 14, more preferably 2 to 10, and even more preferably 2 to 8). If the number of carbon atoms is within the above range, the glass transition temperature of the above-mentioned acrylic polymer can be easily adjusted, making it easier to make the adhesion of the radiation-resistant non-curing adhesive layer more suitable.

[0104] Among the above-mentioned (meth)acrylates having an alicyclic hydrocarbon group, it is preferred to be a (meth)acrylate having a monocyclic aliphatic hydrocarbon ring, and more preferably to be cyclohexyl (meth)acrylate.

[0105] Among the above-mentioned (meth)acrylates containing alkoxy groups, alkyl (meth)acrylates containing aliphatic hydrocarbon groups (with straight or branched chains) are preferred, and even more preferably (meth)acrylates containing alicyclic hydrocarbon groups. In this case, the adhesiveness of the non-curing radiation adhesive layer is well balanced, and the sealing performance of the optoelectronic semiconductor device is even better.

[0106] In order for the non-curing adhesive layer to appropriately exhibit the basic properties such as adhesion or close contact with optical semiconductor elements brought about by the aforementioned alkoxy-containing hydrocarbon-containing (meth)acrylate, the ratio of the aforementioned alkoxy-containing hydrocarbon-containing (meth)acrylate to the total amount of the aforementioned monomer components (100 mol%) is preferably 40 mol% or more, more preferably 50 mol% or more. Furthermore, from the viewpoint of being able to copolymerize with other monomer components and obtain the effects of those other monomer components, the aforementioned ratio is preferably 95 mol% or less, more preferably 80 mol% or less.

[0107] The ratio of alkyl (meth)acrylates having linear or branched aliphatic hydrocarbon groups in the total monomer components constituting the above-mentioned acrylic polymer is preferably 30 mol% or more, more preferably 40 mol% or more, relative to the total amount of the above-mentioned total monomer components (100 mol%). Furthermore, the above ratio is preferably 90 mol% or less, more preferably 70 mol% or less.

[0108] The ratio of (meth)acrylates having alicyclic hydrocarbon groups in the total monomer components constituting the above-mentioned acrylic polymer is preferably 1 mol% or more, more preferably 5 mol% or more, relative to the total amount of the above-mentioned total monomer components (100 mol%). Furthermore, the above ratio is preferably 30 mol% or less, more preferably 20 mol% or less.

[0109] For the purpose of improving cohesion, heat resistance, etc., the above-mentioned acrylic polymer may also contain structural units from the above-mentioned other monomer components, such as the polar group monomer. Only one of the above-mentioned other monomer components may be used, or two or more may be used.

[0110] Preferably, the acrylic polymer contains a hydroxyl-containing monomer as the polar monomer constituting the acrylic polymer. In this case, the acrylic polymer and the radiation-resistant non-curing adhesive layer have excellent water resistance, and even when the sheet for sealing optical semiconductor elements is used in a high humidity environment, it is not easy to produce white haze and has excellent anti-whitening properties.

[0111] The hydroxyl-containing monomers mentioned above are preferably 2-hydroxyethyl methacrylate and 4-hydroxybutyl methacrylate, and more preferably 2-hydroxyethyl methacrylate.

[0112] In order for the non-curing radiation adhesive layer to appropriately exhibit the basic properties such as adhesion or close contact with optical semiconductor devices brought about by the aforementioned alkoxy-containing hydrocarbon (meth)acrylate, the proportion of the polar monomers in the total monomer composition (100 mol%) constituting the aforementioned acrylic polymer is preferably 5 to 50 mol%, more preferably 10 to 40 mol%. In particular, from the viewpoint that the water resistance of the non-curing radiation adhesive layer is also superior, the proportion of hydroxyl monomers is preferably within the above range.

[0113] In order to form a cross-linked structure in its polymer backbone, the aforementioned acrylic polymer may also contain structural units from multifunctional monomers that can copolymerize with the monomer components constituting the acrylic polymer. Examples of such multifunctional monomers, in addition to the aforementioned multifunctional (meth)acrylates, include epoxy (meth)acrylates (e.g., polyglycidyl (meth)acrylate), polyester (meth)acrylate, urethane (meth)acrylate, and monomers having (meth)acrylic acid groups and other reactive functional groups within their molecules. Only one of the aforementioned multifunctional monomers may be used, or two or more may be used.

[0114] In order to properly exhibit the basic properties such as adhesion or close contact with optical semiconductor elements brought about by the above-mentioned (meth)acrylate containing hydrocarbon groups that may have alkoxy groups, the ratio of the above-mentioned multifunctional monomers in the total monomer composition (100 mol%) of the above-mentioned acrylic polymer is preferably 40 mol% or less, and more preferably 30 mol% or less.

[0115] The aforementioned acrylic polymer may also have structural portions derived from the aforementioned crosslinking agent. For example, the aforementioned acrylic polymer can be crosslinked to further reduce low molecular weight substances in the radiation-curing adhesive layer. Furthermore, the weight-average molecular weight of the acrylic polymer can be increased. Only one of the aforementioned crosslinking agents may be used, or two or more may be used.

[0116] The above-mentioned acrylic polymer can be produced by the same method as the above-mentioned acrylic polymer having the first functional group.

[0117] The weight-average molecular weight of the aforementioned acrylic polymer is not particularly limited, but is preferably between 100,000 and 3,000,000, and more preferably between 200,000 and 2,500,000. If the weight-average molecular weight is within the above range, the adhesiveness of the non-curing radiation adhesive layer is well balanced, and the sealing performance of the optoelectronic semiconductor device is even better. Furthermore, the aforementioned weight-average molecular weight refers to the value calculated based on polystyrene by gel permeation chromatography (GPC).

[0118] The aforementioned non-curing radiation adhesive layer may also contain other components besides the aforementioned base polymer, to the extent that the effects of the present invention are not impaired. Examples of these other components are provided and described as other components that may be included in the aforementioned curing radiation adhesive layer. Only one of these other components may be used, or two or more may be used.

[0119] Furthermore, the aforementioned non-curing adhesive layer is preferably located on the surface of the optical stack that becomes the optical semiconductor element when it is laminated on the optical stack (in the case of a release liner, it is the surface of the stack excluding the release liner). For example, in the optical stack 1 shown in FIG1, the adhesive layer 3a includes a first adhesive layer 31 as a curable adhesive layer and a second adhesive layer 32 as a non-curable adhesive layer. The second adhesive layer 32 is located on the surface of the optical stack 1, excluding the release liner 5, opposite to the surface treatment layer 4.

[0120] If the aforementioned non-curing adhesive layer is located on the aforementioned surface, when the aforementioned optical laminate is used as a sealing sheet for the optical semiconductor device described later, and the optical semiconductor device sealing sheet seals the optical semiconductor device, the aforementioned non-curing adhesive layer exhibits excellent adhesion to the optical semiconductor device and the substrate, resulting in excellent sealing performance of the optical semiconductor device. Furthermore, after sealing, the aforementioned curing adhesive layer hardens due to radiation exposure, reducing the adhesion of the sealing sheet's side surface. Consequently, the adhesion between adhesive layers in adjacent optical semiconductor devices in a flat state is lower, making it less likely for sheet defects or adhesion between adjacent optical semiconductor devices to occur when the adjacent optical semiconductor devices are pulled apart. Additionally, when fabricating an optical semiconductor device by laminating the optical laminate onto the optical semiconductor device and subsequently cutting it, the stickiness of the cut portion can be suppressed, resulting in an optical semiconductor device with a good appearance.

[0121] The adhesive layer described above may also contain a layer containing a colorant. With this configuration, when the aforementioned optical semiconductor device is applied to a display, color mixing of light emitted by each optical semiconductor element can be suppressed, thus improving contrast. Furthermore, when the optical semiconductor device is not used, reflections caused by metal wiring, etc., can be prevented, resulting in a good appearance for the display. The layer containing the colorant may be a single layer or two or more layers. For example, the layer containing the colorant may be either the aforementioned hardened adhesive layer or the aforementioned non-hardened adhesive layer, or both.

[0122] The aforementioned colorant is preferably a black colorant. The aforementioned black colorant may be any known or commonly used coloring agent (pigment, dye, etc.) for producing black. Only one black colorant may be used, or two or more may be used. Furthermore, a colorant that functions as a black colorant may also be used in combination and blending with a colorant of a color other than black.

[0123] The thickness of the adhesive layer (the total thickness of the adhesive layer on one surface of the substrate) is preferably 20 to 800 μm, more preferably 30 to 700 μm, and even more preferably 50 to 600 μm. If the thickness is 20 μm or more, the adhesion between the substrate and the adherend is more excellent. If the thickness is 800 μm or less, the adhesive layer can be thinner, and the optical semiconductor device can be thinner.

[0124] The refractive index of the adhesive layers (each layer) is preferably 1.40 to 1.55, and more preferably 1.43 to 1.53. If the refractive index is within the above range, there is a tendency for the refractive index difference with other layers constituting the optical laminate (such as the substrate portion and other layers constituting the substrate portion) to decrease, which can reduce the reflectivity at the interface, improve the visibility of the optical semiconductor device, and reduce the likelihood of color shift. Furthermore, the refractive index of the adhesive layer is a value under the operating condition of the optical laminate, and when the adhesive layer includes a curable adhesive layer, it is a value under the condition that the curable adhesive layer has been cured.

[0125] Regarding the refractive index of the aforementioned adhesive layer, the type or composition of the resin components such as the base polymer, or the content of additives such as fillers, can be adjusted. However, when adjusting using additives such as fillers, although the refractive index is adjusted, it may affect other optical properties (such as haze), making comprehensive adjustments very complex when using laminates for optical applications. On the other hand, when adjusting the type or composition of the resin components, methods for selecting the combination of monomer components constituting the resin can be cited. When using monomer components with conjugated rings, there is a tendency to increase the refractive index; when using silicone or fluorine components, there is a tendency to decrease the refractive index. For example, as a method to increase the refractive index, a method of copolymerizing monomer components containing aromatic rings and having a relatively high refractive index can be used; conversely, as a method to decrease the refractive index, it can be adjusted by copolymerizing components containing fluorine monomers and having a relatively low refractive index. In this case, compared with the case of adjusting by using fillers or other additives, the impact on other optical properties (such as haze) is relatively small, and it is not difficult to make comprehensive adjustments when the laminate is intended for optical use.

[0126] (Surface Treatment Layer) The surface treatment layer is a layer that imparts anti-reflective and / or anti-glare properties to the optical laminate. When the optical laminate is applied to an optical semiconductor element, the surface treatment layer is disposed on the side opposite to the optical semiconductor element relative to the substrate portion. By providing the surface treatment layer, when the optical semiconductor device is applied to a display, the gloss or light reflection of the display can be suppressed, resulting in a good appearance of the display. An example of the anti-glare layer is an anti-glare treatment layer. An example of the anti-reflective layer is an anti-reflective treatment layer. When the surface treatment layer is both an anti-reflective and anti-glare layer, the anti-glare treatment layer and the anti-reflective treatment layer can be a single layer or different layers.

[0127] The aforementioned surface treatment layer is an anti-glare treatment layer and / or an anti-reflection treatment layer. This layer may also be a layer disposed on the surface of at least one of the layers constituting the optical laminate, such as the substrate portion or the adhesive layer. This surface treatment layer is formed by performing anti-glare treatment and / or anti-reflection treatment on the surface of the layer constituting the optical laminate (e.g., the surface of the substrate portion). The anti-glare treatment and anti-reflection treatment can be performed using known or conventional methods.

[0128] Preferably, the surface treatment layer described above is a surface-treated laminate having an optical film and an anti-glare treatment layer and / or an anti-reflection treatment layer disposed on one side of the optical film. Optical films such as polarizing plates often tend to have poor support or operability; by combining them with the aforementioned substrate, the advantages of both can be utilized. Furthermore, by using the aforementioned surface-treated laminate, the optical laminate can be directly applied to optical components. Examples of the aforementioned optical film or surface-treated laminate include anti-reflection (AR) films, polarizing plates, and retardation plates.

[0129] The above-mentioned anti-reflection treatment layer may use known or conventional anti-reflection treatment layers, such as anti-reflection treatment layers.

[0130] The above-mentioned anti-reflective treatment layer can be formed by an anti-reflective layer forming coating liquid. The above-mentioned anti-reflective layer forming coating liquid may also include, for example, resin, fluorine-containing additives, hollow particles, solid particles, and diluents, and may be mixed to manufacture the coating.

[0131] Examples of the above-mentioned resins include thermosetting resins and ionizing radiation-cured resins that cure due to ultraviolet light or light. Commercially available thermosetting resins or ultraviolet-cured resins may also be used as the above-mentioned resins.

[0132] As the aforementioned thermosetting or UV-curing resin, for example, a curing compound having at least one of acrylate or methacrylate groups that is cured by heat, light (ultraviolet light, etc.), or an electron beam can be used. Examples include oligomers or prepolymers of acrylates or methacrylates of polyfunctional compounds such as silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and polyols. Only one of these compounds may be used, or two or more may be used.

[0133] To cure the above-mentioned curing resin, a curing agent may be added, for example. The curing agent is not particularly limited; for example, a known or commonly used polymerization initiator (e.g., a thermal polymerization initiator, a photopolymerization initiator, etc.) may be appropriately used. The amount of the curing agent added is not particularly limited; relative to 100 parts by mass of the resin in the above-mentioned antireflective layer forming coating liquid, it may be, for example, 0.5 parts by mass or more, 1.0 parts by mass or more, 1.5 parts by mass or more, 2.0 parts by mass or more, or 2.5 parts by mass or more, or it may be 15 parts by mass or less, 13 parts by mass or less, 10 parts by mass or less, 7 parts by mass or less, or 5 parts by mass or less.

[0134] The above-mentioned fluorine-containing additives are not particularly limited, and may be, for example, organic or inorganic compounds containing fluorine in their molecules. The above-mentioned organic compounds are not particularly limited, and examples include fluorine-containing antifouling coatings, fluorine-containing acrylic compounds, and fluorine-containing and silicone acrylic compounds. The amount of the above-mentioned fluorine-containing additives added is not particularly limited. For example, relative to the total mass of the solid components in the above-mentioned antireflective layer forming coating liquid, the mass of fluorine in the solid components may be, for example, 0.05% by mass or more, 0.1% by mass or more, 0.15% by mass or more, 0.20% by mass or more, or 0.25% by mass or more, or may be less than 20% by mass, less than 15% by mass, less than 10% by mass, less than 5% by mass, or less than 3% by mass. Furthermore, for example, relative to 100 parts by mass of the resin in the above-mentioned antireflective layer forming coating liquid, the mass of the above-mentioned fluorine-containing additive may be 0.05 parts by mass or more, 0.1 parts by mass or more, 0.15 parts by mass or more, 0.20 parts by mass or more, or 0.25 parts by mass or more, or may be less than 20 parts by mass, less than 15 parts by mass, less than 10 parts by mass, less than 5 parts by mass, or less than 3 parts by mass.

[0135] The hollow particles described above are not particularly limited, and may be, for example, silicon dioxide particles, acrylic acid particles, acrylic-styrene copolymer particles, etc. Examples of silicon dioxide particles include trade names such as "Thrulya 5320" and "Thrulya 4320" (manufactured by Nippon Chemi-Conduct Co., Ltd.). The weight-average particle size of the hollow particles described above is not particularly limited, and may be, for example, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, or 70 nm or more, or less than 150 nm, 140 nm or less, 130 nm or less, 120 nm or less, or 110 nm or less. The shape of the hollow particles described above is not particularly limited, and may be, for example, approximately spherical granules, or irregularly shaped powders, etc. Approximately spherical particles are preferred, more preferably approximately spherical particles with an aspect ratio of 1.5 or less, and most preferably spherical particles. By adding the aforementioned hollow particles, the low refractive index and good anti-reflective properties of the anti-reflective layer can be achieved. The amount of hollow particles added is not particularly limited; relative to 100 parts by mass of the resin in the coating liquid for forming the anti-reflective layer, it can be, for example, 30 parts by mass or more, 50 parts by mass or more, 70 parts by mass or more, 90 parts by mass or more, or 100 parts by mass or more, or it can be less than 300 parts by mass, less than 270 parts by mass, less than 250 parts by mass, less than 200 parts by mass, or less than 180 parts by mass. From the viewpoint of reducing the refractive index of the anti-reflective layer, it is preferable that the amount of hollow particles added is not too small; from the viewpoint of ensuring the mechanical properties of the anti-reflective layer, it is preferable that the amount of hollow particles added is not too large.

[0136] The aforementioned solid particles are not particularly limited, and may be, for example, silicon dioxide particles, zirconium oxide particles, titanium-containing particles (e.g., titanium oxide particles), etc. Examples of the aforementioned silicon dioxide particles include those with trade names such as "MEK-2140Z-AC," "MIBK-ST," and "IPA-ST" (all manufactured by Nissan Chemical Co., Ltd.). The weight-average particle size of the aforementioned solid particles is not particularly limited, and may be, for example, 5 nm or more, 10 nm or more, 15 nm or more, 20 nm or more, or 25 nm or more, or less than 3300 nm, less than 250 nm, less than 200 nm, less than 150 nm, or less than 100 nm. The shape of the aforementioned solid particles is not particularly limited, and may be, for example, approximately spherical granules, or irregularly shaped particles such as powders. Approximately spherical particles are preferred, more preferably approximately spherical particles with an aspect ratio of 1.5 or less, and most preferably spherical particles. By adding the aforementioned solid particles, such as the aforementioned fluorine-containing additive, they can be easily and unevenly distributed on the surface of the coated antireflective layer forming liquid, resulting in excellent scratch resistance of the antireflective layer and achieving low refractive index and good antireflective properties. The amount of the aforementioned solid particles added is not particularly limited. Relative to 100 parts by mass of the aforementioned resin in the antireflective layer forming liquid, it can be, for example, 5 parts by mass or more, 10 parts by mass or more, 15 parts by mass or more, 20 parts by mass or more, or 25 parts by mass or more, or it can be less than 150 parts by mass, less than 120 parts by mass, less than 100 parts by mass, or less than 80 parts by mass.

[0137] The diluent described above may be, for example, a mixed solvent containing methyl isobutyl ketone (MIBK) and propylene glycol monomethyl ether acetate (PMA). In this case, the mixing ratio is not particularly limited. When the mass of MIBK is set to 100 parts by mass, the mass of PMA may be, for example, 20 parts by mass or more, 50 parts by mass or more, 100 parts by mass or more, 150 parts by mass or more, or 200 parts by mass or more, or it may be less than 400 parts by mass, less than 350 parts by mass, less than 300 parts by mass, or less than 250 parts by mass.

[0138] The aforementioned diluent may also be a mixed solvent that includes tert-butanol in addition to methyl isobutyl ketone and propylene glycol monomethyl ether acetate. In this case, the mixing ratio is not particularly limited. When the mass of methyl isobutyl ketone is set to 100 parts by mass, the mass of PMA may be, for example, 10 or more parts by mass, 30 or more parts by mass, 50 or more parts by mass, 80 or more parts by mass, or 100 or more parts by mass, or it may be less than 200 parts by mass, less than 180 parts by mass, less than 150 parts by mass, less than 130 parts by mass, or less than 110 parts by mass. Similarly, when the mass of MIBK is set to 100 parts by mass, the mass of tert-butanol may be, for example, 10 or more parts by mass, 30 or more parts by mass, 50 or more parts by mass, 80 or more parts by mass, or 100 or more parts by mass, or it may be less than 200 parts by mass, less than 180 parts by mass, less than 150 parts by mass, less than 130 parts by mass, or less than 110 parts by mass.

[0139] The amount of the diluent added is not particularly limited. For example, the mass of the solid component relative to the total mass of the coating liquid for forming the antireflective layer may be 0.1% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 1.0% by mass or more, or 1.5% by mass or more, or it may be 20% by mass or less, 15% by mass or less, 10% by mass or less, 5% by mass or less, or 3% by mass or less. From the viewpoint of ensuring coatability (wetting, leveling), it is preferable that the content of the solid component is not too high. From the viewpoint of preventing uneven drying, whitening, and other appearance defects caused by drying, it is preferable that the content of the solid component is not too low.

[0140] A known or conventional anti-glare treatment layer may be used as the aforementioned anti-glare treatment layer. The aforementioned anti-glare treatment layer may be a known or conventional one, and is generally formed as a layer in which inorganic or organic particles as anti-glare agents are dispersed in the resin.

[0141] The above-mentioned anti-glare treatment layer is not particularly limited. For example, it can be formed using an anti-glare treatment layer forming material containing resin, particles, and a thixotropic agent, and a protrusion is formed on the surface of the anti-glare treatment layer by the aggregation of the particles and the thixotropic agent. With this configuration, the anti-glare treatment layer has excellent display characteristics that take into account both anti-glare and anti-white spots. Moreover, although the anti-glare treatment layer is formed by the aggregation of particles, it can still prevent the formation of protrusions on the surface of the anti-glare treatment layer that would become appearance defects, thereby improving the yield of the product.

[0142] Examples of the above-mentioned resins include thermosetting resins and ionizing radiation-cured resins that cure due to ultraviolet light or light. Commercially available thermosetting resins or ultraviolet-cured resins may also be used as the above-mentioned resins.

[0143] As the aforementioned thermosetting or UV-curing resin, for example, a curing compound that is cured by heat, light (ultraviolet light, etc.), or an electron beam, such as an acrylate or methacrylate oligomer or prepolymer, may be used. Examples include silicone resin, polyester resin, polyether resin, epoxy resin, urethane resin, alkyd resin, spiroacetal resin, polybutadiene resin, polythiol polyene resin, polyol, and other polyfunctional compounds such as acrylates or methacrylates. Only one type may be used, or two or more types may be used.

[0144] The main function of the particles used to form the above-mentioned anti-glare treatment layer is to make the surface of the formed anti-glare treatment layer uneven to impart anti-glare properties, and to control the haze value of the anti-glare treatment layer. The haze value of the anti-glare treatment layer can be designed by controlling the refractive index difference between the particles and the resin. The particles include, for example, inorganic particles and organic particles. There are no particular limitations on the inorganic particles, and examples include: silicon oxide particles, titanium oxide particles, aluminum oxide particles, zinc oxide particles, tin oxide particles, zirconium oxide particles, calcium carbonate particles, barium sulfate particles, talc particles, kaolin particles, calcium sulfate particles, etc. There are also no particular limitations on the organic particles, and examples include: polymethyl methacrylate resin powder, silicone resin powder, polystyrene resin powder, polycarbonate resin powder, acrylic-styrene resin powder, benzoguanamine resin powder, melamine resin powder, polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, polyvinyl fluoride resin powder, etc. These inorganic and organic particles may be used in single or multiple forms.

[0145] The aforementioned anti-glare treatment layer may also include a thixotropic agent. By including the aforementioned thixotropic agent, the aggregation state of the aforementioned particles can be easily controlled. Examples of thixotropic agents used to form the aforementioned anti-glare treatment layer include organoclay, oxidized polyolefin, and modified urea. Only one type of thixotropic agent may be used, or two or more types may be used.

[0146] To improve compatibility with the aforementioned resin, the aforementioned organoclay is preferably an organochemically treated clay. Examples of organoclay include layered organoclay. The aforementioned organoclay can be prepared in-house or commercially available products can be used. Examples of commercially available products mentioned above include: "Lucentite SAN", "Lucentite STN", "Lucentite SEN", "Lucentite SPN", "Somasif ME-100", "Somasif MAE", "Somasif MTE", "Somasif MEE", and "Somasif MPE" (all manufactured by Katakura & Co-op Agri Co., Ltd.); "S-BEN", "S-BEN C", "S-BEN E", "S-BEN W", "S-BEN P", "S-BEN WX", "S-BEN N-400", "S-BEN NX", "S-BEN NX80", "S-BEN NO12S", and "S-BEN..." The following are product names: “NEZ”, “S-BEN NO12”, “S-BEN NE”, “S-BEN NZ”, “S-BEN NZ70”, “Orgonite”, “Orgonite D”, “Orgonite T” (all manufactured by Ho Jun Co., Ltd.); “Kunipia F”, “Kunipia G”, “Kunipia G4” (all manufactured by Kunimine Industries Co., Ltd.); “Tixogel VZ”, “Kraton HT”, “Kraton 40” (all manufactured by Rockwood Additives Co., Ltd.).

[0147] The above-mentioned oxidized polyolefins can be prepared in-house or commercially available products can be used. Examples of such commercially available products include "Disparlon 4200-20" (manufactured by Kusumoto Chemical Co., Ltd.) and "Fronon SA300" (manufactured by Kyoei Chemical Co., Ltd.).

[0148] The modified urea described above is a reaction product of isocyanate monomers or their adducts with organic amines. The modified urea can be prepared in-house or commercially available products can be used. Examples of commercially available products include "BYK410" (trade name, manufactured by BYK Corporation).

[0149] The refractive index of the surface treatment layer is preferably 1.40 to 1.55, and more preferably 1.43 to 1.53. If the refractive index is within the above range, there is a tendency for the refractive index difference with other layers constituting the optical laminate (e.g., other layers constituting the substrate portion) to decrease, which can reduce the reflectivity at the interface, improve the visibility of the optical semiconductor device, and reduce the likelihood of color shift. Furthermore, when the surface treatment layer is a surface treatment laminate containing an optical film, the refractive index of the surface treatment laminate is used as the refractive index of the surface treatment layer.

[0150] In the optical laminate 1 shown in FIG1, the surface treatment layer 4 is a surface treatment laminate comprising an optical film 41 and an anti-glare and anti-reflection treatment layer 42 disposed on the surface of the optical film 41. The optical film 41 in the surface treatment layer 4 is bonded to the substrate portion 2 via a third adhesive layer 33.

[0151] (Release Pad) The release pad is a component used to cover and protect the surface of the adhesive layer on the optical semiconductor element side of the substrate when the optical multilayer is applied to the optical semiconductor element, and to peel off from the multilayer when the optical semiconductor element is attached to the substrate on which the optical semiconductor element is disposed.

[0152] Examples of the release liner mentioned above include polyethylene terephthalate (PET) film, polyethylene film, polypropylene film, plastic film or paper that has been coated with a release agent such as a fluorinated release agent or an acrylic long-chain alkyl ester release agent.

[0153] 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. If the thickness is 10 μm or more, the release liner is less likely to break due to cutting during processing. If the thickness is 200 μm or less, the release liner is easier to peel off from the adhesive layer during use.

[0154] (Optical stack) The refractive index difference between the substrate layer (A) and the adhesive layer is preferably 0.10 or less, more preferably 0.07 or less, and even more preferably 0.05 or less. If the refractive index difference is 0.10 or less, when the optical stack is applied to an image display device, light reflection between the substrate layer (A) and the adhesive layer can be reduced. As a result, the light extraction efficiency of the optical semiconductor device is excellent due to the reduced reflectivity between the layers, and color shift can be suppressed. Furthermore, when multiple adhesive layers are provided, it is sufficient that the refractive index difference between the substrate layer (A) and at least one adhesive layer is within the above range. Preferably, the refractive index difference between the substrate layer (A) and all adhesive layers in the optical stack is within the above range. Furthermore, the refractive index of the aforementioned adhesive layer is the value under the use state of the optical laminate. When the aforementioned adhesive layer is a hardening layer (hardening layer) or the like, it is the value under the hardened state of the hardening layer.

[0155] The refractive index difference between the substrate layer (A) and the surface treatment layer is preferably 0.10 or less, more preferably 0.07 or less, and even more preferably 0.05 or less. If the refractive index difference is 0.10 or less, when the optical laminate is applied to an image display device, light reflection between the substrate layer (A) and the surface treatment layer can be reduced. As a result, the light extraction efficiency of the optical semiconductor device is excellent due to the reduced reflectivity between the layers, and color shift can be suppressed. Furthermore, when the surface treatment layer is a surface treatment laminate containing an optical film, the refractive index of the surface treatment laminate is used as the refractive index of the surface treatment layer.

[0156] In the above-described optical laminate, when the side with the substrate portion opposite to the side having the surface treatment layer is bonded to a sheet with a frontal reflectance of 40.34% and the measurement is performed, the ratio of the brightness measured at an angle of 45° from the vertical direction relative to the front surface (45° brightness) to the brightness measured from the vertical direction relative to the front surface (front brightness) [45° brightness / front brightness] is preferably 0.95 or more (e.g., 0.95 to 1.0), more preferably 0.97 or more, and even more preferably 0.98 or more. If the ratio is 0.95 or more, when the above-described optical laminate is applied to an image display device, an image display device that is bright and has a good appearance when viewed from any direction can be provided. Furthermore, the above ratio is a value in the use state of the optical laminate, and in the case where the optical laminate has a hardened layer, for example, it is a value in the state where the layer has been hardened.

[0157] In the above-described optical laminate, when the side having the substrate portion opposite to the side having the surface treatment layer is bonded to a sheet with a frontal reflectance of 40.34% and the measurement is performed, the frontal reflectance is preferably 3.2% or less, and more preferably 3.1% or less. With a frontal reflectance of 3.2% or less, when applied to an image display device, an image display device that prevents reduced visibility due to reflection of external light or image projection, and whose appearance is adjusted, can be provided. Furthermore, the above-described frontal reflectance is a value under the operating state of the optical laminate, and in the case where the optical laminate has a hardened layer, for example, it is a value under the hardened state of that layer.

[0158] One embodiment of the manufacturing method of the optical laminate of the present invention will be described. For example, the optical laminate 1 shown in FIG1 can be manufactured by the following method. First, a first adhesive layer 31 is formed on the substrate portion 2. The first adhesive layer 31 can be manufactured by applying an adhesive composition for forming the first adhesive layer 31 to one side of the substrate portion 2 to form an adhesive composition layer, and then performing curing by means of heat-induced desolvation or thermosetting, thereby curing the adhesive composition layer. When the thickness of the first adhesive layer 31 is relatively thick, a first adhesive layer separately manufactured on the release treatment surface of the release liner in the same manner can also be stacked on the first adhesive layer formed on the substrate portion 2.

[0159] The adhesive composition forming the first adhesive layer described above can be in any form. For example, the adhesive composition can be an emulsion type, a solvent type (solution type), a hot-melt type, etc. Among these, a solvent type is preferred in terms of ease of obtaining an adhesive layer with excellent productivity.

[0160] On the other hand, a second adhesive layer 32 is formed on the release treatment surface of the separately prepared release liner 5. The second adhesive layer 32 can be made by applying an adhesive composition for forming the second adhesive layer 32 onto the release treatment surface of the release liner 5 to form an adhesive composition layer, followed by desolvation or curing by heating to cure the adhesive composition layer. Then, the second adhesive layer is deposited on the first adhesive layer. In this way, a laminate having the structure of [substrate portion 2 / first adhesive layer 31 / second adhesive layer 32 / release liner 5] is obtained.

[0161] The adhesive composition forming the second adhesive layer described above can be in any form. For example, the adhesive composition can be an emulsion type, a solvent type (solution type), an active energy line curing type, a hot-melt type, etc. Among these, solvent type and active energy line curing type adhesive compositions are preferred in terms of ease of obtaining an adhesive layer with excellent productivity.

[0162] On the other hand, a laminate consisting of a surface treatment layer 4 and a third adhesive layer 33 is fabricated. Specifically, for example, the third adhesive layer 33 can be formed on the release treatment surface of a separately prepared release liner in the same manner as the second adhesive layer 32, and then the untreated surface of the surface treatment layer 4, which is an optical film treated with anti-reflection and / or anti-glare, is bonded to the third adhesive layer 33. Subsequently, the release liner is peeled off to expose the third adhesive layer 33, and it is bonded to the surface of the substrate portion 2 of the laminate where the first adhesive layer 31 is not formed. The coating method of the adhesive composition can be, for example, a known or conventional coating method, such as roller coating, screen coating, gravure coating, etc. Furthermore, the lamination of various layers can be performed using a known roller or laminating machine. In this way, the optical laminate 1 shown in FIG1 can be fabricated.

[0163] Furthermore, the optical laminate 1 is not limited to the above method. It can also be made by laminating the substrate 2 and the surface treatment layer 4 through the adhesive layer 33, and then appropriately combining the first adhesive layer 31 and the second adhesive layer 32 and sequentially laminating them on the exposed surface of the substrate 2.

[0164] The optical stacking system of the present invention is used by directly or indirectly stacking on optical semiconductor devices. Preferably, the optical stack of the present invention is stacked on a substrate on which optical semiconductor devices are disposed. Preferably, the optical stack of the present invention is a sheet (sometimes referred to as "sealable sheet for optical semiconductor devices") for sealing one or more optical semiconductor devices disposed on a substrate. Furthermore, in this specification, "sealing the optical semiconductor device" means embedding at least a portion of the optical semiconductor device into the adhesive layer provided by the optical stack.

[0165] By using the optical laminate of the present invention and attaching it to a substrate on which optical semiconductor elements are disposed, an optical semiconductor device can be obtained. When the optical laminate of the present invention is a sheet for sealing optical semiconductor elements, the optical semiconductor device can be obtained by attaching the sheet for sealing optical semiconductor elements to a substrate on which optical semiconductor elements are disposed via an adhesive layer or other adhesive layer, and sealing the optical semiconductor elements using the adhesive layer.

[0166] When the aforementioned optical semiconductor device sealing sheet has an adhesive layer on the side of the substrate portion opposite to the surface treatment layer side, specifically, firstly, the release liner is peeled off from the aforementioned optical semiconductor device sealing sheet to expose the adhesive layer. Then, the exposed surface of the aforementioned optical semiconductor device sealing sheet, i.e., the adhesive layer, is adhered to the substrate surface of an optical component having a substrate and optical semiconductor devices (preferably a plurality of optical semiconductor devices) disposed on the substrate. When the optical component has a plurality of optical semiconductor devices, the adhesive layer is used to fill the gaps between the plurality of optical semiconductor devices, thereby sealing the plurality of optical semiconductor devices together. In this manner, the aforementioned optical semiconductor device sealing sheet can be used to seal the optical semiconductor device. Furthermore, the aforementioned optical semiconductor device sealing sheet can also be used to seal the optical semiconductor device under reduced pressure or by applying pressure while adhering. Examples of such methods include those disclosed in Japanese Patent Application Publication No. 2016-29689 or Japanese Patent Application Publication No. Hei 6-97268.

[0167] [Optical Semiconductor Device] An optical semiconductor device can be fabricated using the optical multilayer of the present invention. The optical semiconductor device manufactured using the optical multilayer of the present invention includes a substrate, an optical semiconductor element disposed on the substrate, and the optical multilayer of the present invention deposited on the optical semiconductor element. When the optical multilayer has a curable adhesive layer, the adhesive layer in the optical semiconductor device can also be cured. When the optical multilayer of the present invention is a sheet for sealing optical semiconductor elements, the adhesive layer seals the optical semiconductor element.

[0168] Examples of the aforementioned light semiconductor elements include blue light-emitting diodes, green light-emitting diodes, red light-emitting diodes, ultraviolet light-emitting diodes, and other light-emitting diodes (LEDs).

[0169] When the optical stack in the above-mentioned optical semiconductor device is a sheet for sealing optical semiconductor elements, the sheet for sealing optical semiconductor elements is preferably used to seal a plurality of optical semiconductor elements together.

[0170] FIG2 illustrates one embodiment of an optical semiconductor device using the optical stack 1 shown in FIG1. ​​The optical semiconductor device 10 shown in FIG2 includes a substrate 6, a plurality of optical semiconductor elements 7 disposed on one side of the substrate 6, and a hardened portion 1' of the optical stack that seals the optical semiconductor elements 7. In the hardened portion 1' of the optical stack, the release liner 5 has been peeled off from the optical stack 1, and a hardened sealing layer 31' has been formed by hardening a first adhesive layer 31, which is a radiation-hardening adhesive layer, by irradiation. The plurality of optical semiconductor elements 7 are sealed together in the hardened sealing portion 31' and the second adhesive layer 32. The second adhesive layer 32 follows the uneven shape formed by the plurality of optical semiconductor elements 7 and is closely attached to the optical semiconductor elements 7 and the substrate 6, embedding the optical semiconductor elements 7 therein.

[0171] Furthermore, in the optical semiconductor device 10 shown in FIG2, the optical semiconductor element 7 is completely embedded in the second adhesive layer 32 and sealed, and indirectly sealed by the hardened sealing layer 31'. The above-described optical semiconductor device is not limited to this form, and may also be in the form where a portion of the optical semiconductor element 7 protrudes from the second adhesive layer 32, and this portion is embedded in the hardened sealing layer 31', and the optical semiconductor element 7 is completely embedded and sealed by the second adhesive layer 32 and the hardened sealing layer 31'.

[0172] The aforementioned optical semiconductor device may also be formed by laying out individual optical semiconductor devices in a flat manner. That is, in the aforementioned optical semiconductor device, a plurality of optical semiconductor devices may be arranged in a brick-like shape in a planar direction.

[0173] Figure 3 shows one embodiment of an optical semiconductor device fabricated by arranging a plurality of optical semiconductor devices. The optical semiconductor device 20 shown in Figure 3 is formed by arranging (laying flat) a plurality of optical semiconductor devices 10 in a planar direction in a brick-like manner, with 4 in the longitudinal direction and 4 in the transverse direction. At the junction 20a between two adjacent optical semiconductor devices 10, the optical semiconductor devices 10 are adjacent to each other, but they can be easily pulled apart, and it is not easy to cause defects on the side of the optical laminate, or for resin with defects in the side of the optical laminate to adhere from one of the adjacent optical semiconductor devices to the other.

[0174] The aforementioned optical semiconductor device is preferably a backlight device for a liquid crystal display (LCD), and more preferably a full-surface direct-lit backlight device. Furthermore, an image display device can be manufactured by combining the aforementioned backlight device with a display panel. When the aforementioned optical semiconductor device is a backlight device for an LCD, the optical semiconductor element is an LED element. For example, in the aforementioned backlight device, a metal wiring layer for transmitting light emission control signals to each LED element is disposed on the aforementioned substrate. LED elements emitting red (R), green (G), and blue (B) light are alternately arranged on the substrate of the display panel, separated by the metal wiring layer. The metal wiring layer is formed of a metal such as copper and reflects the light emitted by each LED element, thus reducing image visibility. Furthermore, the light emitted by the RGB LED elements mixes, reducing contrast.

[0175] Furthermore, the aforementioned optical semiconductor device is preferably a self-emissive display device. Also, an image display device can be manufactured by combining the aforementioned self-emissive display device with a display panel used as needed. When the aforementioned optical semiconductor device is a self-emissive display device, the optical semiconductor element is an LED element. Examples of the aforementioned self-emissive display device include organic electroluminescent (organic EL) display devices or the aforementioned backlight device. For example, in the aforementioned self-emissive display device, a metal wiring layer for transmitting light emission control signals to each LED element is deposited on the substrate. Each LED element emitting red (R), green (G), and blue (B) light is alternately arranged on the substrate through the metal wiring layer. The metal wiring layer is formed of a metal such as copper, and each color is displayed by adjusting the light emission level of each LED element.

[0176] The optical stack of the present invention can be used in optical semiconductor devices that are bent for use, such as optical semiconductor devices having a bendable image display device (flexible display) (especially a foldable image display device). Specifically, it can be used in foldable backlight devices and foldable self-emissive display devices, etc.

[0177] The optical stack of the present invention can be preferably used in either the case where the above-mentioned optical semiconductor device is a small LED display device or a micro LED display device.

[0178] [Manufacturing Method of Optical Semiconductor Device] The optical semiconductor device described above can be manufactured, for example, by a manufacturing method including a step (deposition step) of laminating the optical stack onto the optical semiconductor element disposed on the substrate. When the optical stack is a semiconductor element sealing sheet, the manufacturing method may also include, in the lamination step, attaching the semiconductor element sealing sheet to the optical semiconductor element and embedding the optical semiconductor element by means of the adhesive layer.

[0179] When the optical laminate has a curable adhesive layer, the manufacturing method may further include the following step (curing step): curing the curable adhesive layer on the laminate obtained through the lamination step to obtain the cured product. The laminate includes the substrate, an optical semiconductor element disposed on the substrate, and the optical laminate deposited on the optical semiconductor element. The manufacturing method may further include the step of cutting the laminate obtained through the lamination step or the curing step to obtain an optical semiconductor device (cutting step). Furthermore, the manufacturing method may further include a tiling step of arranging a plurality of optical semiconductor devices obtained in the cutting step in a planar contact manner. Hereinafter, the manufacturing methods of the optical semiconductor device 10 shown in FIG2 and the optical semiconductor device 20 shown in FIG3 will be described with appropriate reference.

[0180] (Lamination Step) In the above-described deposition step, the optical laminate is laminated onto a substrate on which optical semiconductor elements are disposed, preferably by embedding the optical semiconductor elements using the adhesive layer. Specifically, in the above-described deposition step, as shown in FIG4, the adhesive layer 3a of the optical laminate 1, which has been peeled off from the release liner 5, is arranged so that it faces the side of the substrate 6 on which the optical semiconductor elements 7 are disposed. The optical laminate 1 is laminated onto the side of the substrate 6 on which the optical semiconductor elements 7 are disposed, and as shown in FIG5, the optical semiconductor elements 7 are embedded into the second adhesive layer 32. In order to cut off the ends in the cutting step to ensure consistent dimensions, as shown in FIG4, the substrate 6 used for lamination extends wider in the planar direction than the substrate 6 in the optical semiconductor device 10 shown in FIG2, and no optical semiconductor elements 7 are disposed near the ends of the substrate 6. Furthermore, the optical laminate 1 used for lamination extends wider in the planar direction than the substrate 6 used for lamination. That is, the area of ​​the optical laminate 1 bonded in the lamination step facing the substrate 6 is larger than the area of ​​the substrate 6 bonded in the lamination step facing the optical laminate 1.

[0181] The temperature during the above-mentioned bonding process is, for example, within the range of room temperature to 150°C. Furthermore, pressure can be applied or depressurized during the bonding process. Depressurization or pressure application can suppress the formation of voids between the adhesive layer and the substrate or optical semiconductor element. In the above-mentioned lamination step, it is preferable to bond the optical laminate under depressurization followed by pressure application. The pressure during depressurization is, for example, 1 to 100 Pa, and the depressurization time is, for example, 5 to 600 seconds. The pressure during pressure application is, for example, 0.05 to 0.5 MPa, and the depressurization time is, for example, 5 to 600 seconds.

[0182] (Curing Step) In the above-described curing step, curing is performed according to the type of curability of the curable adhesive layer. When the adhesive layer has thermosetting properties, heating is performed; when it has radiosetting properties, radiation irradiation is performed. In the above-described curing step, the adhesive layer is cured by heating or radiation irradiation on the substrate to which the optical semiconductor element is disposed, formed by bonding the optical laminate (e.g., the laminate obtained in the above-described lamination step). Specifically, in the above-described curing step, as shown in FIG6, the first adhesive layer 31 is cured to form a cured sealing layer 3', obtaining a cured optical laminate 1'. The heating temperature is, for example, in the range of 80 to 200°C, and the heating time is, for example, 1 minute to 24 hours. Furthermore, as mentioned above, the radiation can include electron beams, ultraviolet light, alpha rays, beta rays, gamma rays, X-rays, etc. Among these, ultraviolet light is preferred. The temperature during radiation irradiation is, for example, in the range of room temperature to 100°C, and the irradiation time is, for example, 1 minute to 1 hour.

[0183] (Cutting Step) In the above-described cutting step, the laminated body that has undergone the above-described stacking step or the above-described curing step is cut. Here, in the laminated body undergoing the cutting step, as described above, the hardened part 1' of the optical laminated body and the substrate 6 extend wider in the planar direction than the final optical semiconductor device 10. Moreover, in the above-described cutting step, the side ends of the hardened part and the substrate of the optical laminated body are cut and removed. Specifically, the side ends are removed by cutting at the position of the chain line shown in FIG. 7. The above-described cutting can be performed by known or conventional methods, such as by using a cutting blade or by laser irradiation. In this way, an optical semiconductor device 10 as shown in FIG. 2 can be manufactured, for example.

[0184] (Tiling Step) In the tiling step described above, a plurality of optical semiconductor devices obtained in the cutting step are laid side by side in a planar manner, in contact with each other. In this manner, an optical semiconductor device 20, as shown in FIG3, can be manufactured, for example. [Example]

[0185] The present invention will be described in more detail below by way of example embodiments, but the present invention is not limited to these embodiments.

[0186] Example 1 <Anti-reflective layer / anti-glare layer / TAC film> (Anti-glare layer) 40% by weight of UV-curable urethane acrylate resin (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "NK OLIGO UA-53H-80BK"), 57.5 parts by weight of multifunctional acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat#300"), mainly composed of pentaerythritol triacrylate, 2.5 parts by weight of a diluent for an optical adjustment layer composition containing zirconium oxide particles and UV-curable resin ("Opstar Z7540", manufactured by JSR Co., Ltd.), 2.8 parts by weight of silicone particles (manufactured by Momentive Performance Materials Japan LLC, trade name "Tospearl 130ND"), and thixotropic organic clay, namely synthetic bentonite (manufactured by Kunimine Industries Co., Ltd., trade name "Sumecton"), which is used as a thixotropic agent. The following mixtures were prepared: 2.5 parts by weight of SAN (a photopolymerization initiator, manufactured by BASF, trade name "OMNIRAD907"), 3 parts by weight of crosslinked acrylic-styrene copolymer microparticles (manufactured by Sekisui Chemicals Co., Ltd., trade name "SSX-103DXE"), and 0.1 parts by weight of leveling agent (manufactured by Kyoei Chemical Co., Ltd., trade name "LE-303"). Furthermore, the above-mentioned organoclay was diluted with toluene to a solid content of 6 parts by weight. The mixture was diluted with a toluene / cyclopentanone mixed solvent (mass ratio 64 / 36) to a solid content concentration of 38 parts by weight, and an anti-glare layer forming material (coating liquid) was prepared using an ultrasonic disperser.

[0187] A transparent plastic film (triacetin cellulose (TAC) film, trade name "TJ40UL", Fuji Film Co., Ltd., thickness: 40 μm) was prepared. The anti-glare layer forming material was applied to one side of the transparent plastic film using a bar coater to form a coating. The coating was then dried by heating at 95°C for 1 minute. Subsequently, the coating was hardened by irradiation with ultraviolet light at a cumulative intensity of 300 mJ / cm² using a high-pressure mercury lamp to produce an anti-glare layer (thickness 6.5 μm).

[0188] (Antireflective layer) 100 parts by weight of a multifunctional acrylate (trade name "Viscoat#300", manufactured by Osaka Organic Chemical Industry Co., Ltd.) with pentaerythritol triacrylate as the main component, 100 parts by weight of hollow silicon dioxide nanoparticles (trade name "Thrulya 5320", manufactured by Nichibukai Chemical Co., Ltd.), 40 parts by weight of solid silicon dioxide nanoparticles (trade name "MIBK-ST", manufactured by Nissan Chemical Co., Ltd., solid content 30% by weight, average particle size 10 nm), 12 parts by weight of fluorine-containing additive (trade name "KY-1203", manufactured by Shin-Etsu Chemical Industry Co., Ltd.), 5 parts by weight of photopolymerization initiator (trade name "OMNIRAD907", manufactured by IGM. RESINS B. V.), and 5 parts by weight of photopolymerization initiator (trade name "OMNIRAD2959", manufactured by IGM. RESINS B. V.) are mixed together. A mixed solvent consisting of methyl isobutyl ketone and propylene glycol monomethyl ether acetate in a mass ratio of 70:30 was added to the mixture as a diluent to make the total solid content 1.5% by mass, and the mixture was stirred to prepare a material for forming an antireflective layer.

[0189] The anti-reflective layer forming material described above is applied to the anti-glare layer of the TAC film having the anti-glare layer on its surface using a wire bar coater. The applied anti-reflective layer forming material is heated at 80°C for 1 minute to dry it and form a coating film. The dried coating film is then irradiated with ultraviolet light with a cumulative light intensity of 300 mJ / cm2 using a high-pressure mercury lamp to perform a curing treatment. This hardens the coating film, forming an anti-reflective layer with a thickness of 0.1 μm. A surface treatment layer having a multilayer structure of [anti-reflective layer / anti-glare layer / TAC film] is thus produced.

[0190] <Anti-reflective layer / anti-glare layer / TAC film / adhesive layer> 69.7 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of 2-methoxyethyl acrylate, 13 parts by weight of 2-hydroxyethyl acrylate, 6 parts by weight of N-vinyl-2-pyrrolidone, 1.3 parts by weight of N-hydroxyethylacrylamide, 0.1 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator, and 200 parts by weight of ethyl acetate as a polymerization solvent were added to a separable flask and nitrogen gas was introduced while stirring for 1 hour. This method removed oxygen from the polymerization system. The mixture was then heated to 63°C and reacted for 10 hours. Ethyl acetate was then added to obtain an acrylic polymer solution with a solid content concentration of 30 parts by weight. An adhesive composition (solution) was prepared by adding 0.2 parts by weight of an isocyanate-based crosslinking agent (trade name "Takenate D110N", manufactured by Mitsui Chemicals Co., Ltd.) as a crosslinking agent, 0.15 parts by weight of γ-glycidoxypropyltrimethoxysilane (trade name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent, and 0.2 parts by weight of a polyol formed by the addition of p-ethylenediamine to propylene oxide (trade name "EDP-300", manufactured by ADEKA Co., Ltd.) as a crosslinking accelerator. Next, the adhesive composition was coated onto the release surface of a release liner (isolation element) (trade name "MRF38", manufactured by Mitsubishi Chemical Co., Ltd.) to a thickness of 25 μm after drying. The liner was then dried by heating at 60°C for 1 minute and then at 155°C for 1 minute under normal pressure to obtain a double-sided adhesive sheet as the adhesive layer. Subsequently, using a manual roller to adhere the adhesive layer to the untreated surface of the TAC film in the surface treatment layer obtained above in a bubble-free manner. In this way, a laminate with a [anti-reflective layer / anti-glare layer / TAC film / adhesive layer / release liner] is produced.

[0191] <Polycarbonate film / UV-curable adhesive layer / non-curable adhesive layer> (UV-curable adhesive layer) 189.77 parts by mass of butyl acrylate, 38.04 parts by mass of cyclohexyl acrylate, 85.93 parts by mass of 2-hydroxyethyl acrylate, 0.94 parts by mass of 2,2'-azobisisobutyronitrile (2,2'-azobisisobutyronitrile) as a polymerization initiator, and 379.31 parts by mass of methyl ethyl ketone (379.31 parts by mass) as a polymerization solvent were added to a 1 L round-bottom separable flask equipped with a separable hood, separatory funnel, thermometer, nitrogen inlet tube, Liebig condenser, vacuum seal, stir bar, and stirrer blades. The mixture was stirred and purged with nitrogen at room temperature for 6 hours. Subsequently, polymerization was carried out under nitrogen flow and stirring at 65°C for 4 hours, followed by 75°C for 2 hours, to obtain a resin solution. The obtained resin solution was then cooled to room temperature. Subsequently, 5.74 parts by weight of ethyl 2-isocyanate methacrylate (trade name "Karenz MOI", manufactured by Showa Denko Co., Ltd.) was added to the above resin solution as a compound with polymerizable carbon-carbon double bonds. Then, 0.03 parts by weight of dibutyltin dilaurate (IV) (manufactured by Fuji Film Wako Pure Chemical Co., Ltd.) was added, and the mixture was stirred at 50°C for 24 hours in an air atmosphere to obtain a base polymer. 1.5 parts by weight of an isocyanate compound (trade name "Coronate L", manufactured by Tosoh Co., Ltd., solid content 75 parts by weight) and 1 part by weight of 2,2-dimethoxy-1,2-diphenyl-1-one (trade name "omnirad 651", manufactured by IGM Resins Italia Srl) were mixed with 100 parts by weight of the obtained base polymer solid content. The mixture was adjusted to a solid content ratio of 20 to 40 parts by weight using toluene as a diluent to obtain an adhesive solution (1).

[0192] A polycarbonate film with a thickness of 70 μm was made by extrusion film forming of polycarbonate resin (trade name "DURABIO T7450A", manufactured by Mitsubishi Chemical Co., Ltd.) as the substrate layer. The adhesive solution (1) was applied to the substrate layer with a thickness of 112.5 μm after drying. The film was dried by heating at 50°C for 1 minute and then at 125°C for 5 minutes under normal pressure to form an ultraviolet-curable adhesive layer (1). On the other hand, the adhesive solution (1) obtained above was applied to the release treatment surface of the release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Co., Ltd.) with a thickness of 112.5 μm after drying. The film was dried by heating at 50°C for 1 minute and then at 125°C for 5 minutes under normal pressure to form an ultraviolet-curable adhesive layer (2).

[0193] Next, using a manual roller, the adhesive layers of the UV-curable adhesive layer (1) formed on the polycarbonate film and the UV-curable adhesive layer (2) formed on the release liner are bonded together in a bubble-free manner to form a UV-curable adhesive layer. Then the release liner is peeled off. In this way, a laminate having the structure of [polycarbonate film / UV-curable adhesive layer] is produced.

[0194] (Non-curing adhesive layer) 189.77 parts by weight of butyl acrylate, 38.04 parts by weight of cyclohexyl acrylate, 85.93 parts by weight of 2-hydroxyethyl acrylate, 0.94 parts by weight of 2,2'-azobisisobutyronitrile (2,2'-azobisisobutyronitrile) as a polymerization initiator, and 379.31 parts by weight of methyl ethyl ketone (379.31 parts by weight of methyl ethyl ketone) as a polymerization solvent were added to a 1 L round-bottom separable flask equipped with a separable hood, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stir bar, and a stirrer blade. The mixture was stirred and purged with nitrogen at room temperature for 6 hours. Subsequently, polymerization was carried out under nitrogen flow while stirring at 65°C for 4 hours and then at 75°C for 2 hours to obtain a resin solution. To the obtained resin solution, 1.5 parts by mass of an isocyanate compound (trade name "Coronate L", manufactured by Tosoh Co., Ltd., solid content 75 parts by mass) were mixed with 100 parts by mass of the base polymer solid content. The solution was adjusted using toluene as a diluent to a solid content ratio of 20 to 40 parts by mass to obtain an adhesive solution (2).

[0195] The adhesive solution (2) was applied to the release treatment surface of the release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Co., Ltd.) with a thickness of 25 μm after drying, and then dried by heating at 125°C for 2 minutes under normal pressure to form a non-hardening adhesive layer.

[0196] (Polycarbonate film / UV-curable adhesive layer / non-curable adhesive layer) Using a hand roller, the non-curable adhesive layer is bonded to the UV-curable adhesive layer of the laminate having the [polycarbonate film / UV-curable adhesive layer] laminate structure in a bubble-free manner. A laminate having the [polycarbonate film / UV-curable adhesive layer / non-curable adhesive layer / release liner] laminate structure is thus produced.

[0197] <Optical Laminate (Optical Semiconductor Sealing Sheet)> The release liner is peeled off from the laminate having a structure of [polycarbonate film / adhesive layer / release liner], and the exposed adhesive layer is bonded to the substrate surface of the laminate having a structure of [polycarbonate film / UV-curable adhesive layer / non-curable adhesive layer / release liner] using a hand roller in a bubble-free manner. Subsequently, it is cured at 50°C for 48 hours to produce the optical laminate of Example 1 having a layer structure of [anti-reflective layer / anti-glare layer / TAC film / adhesive layer / polycarbonate film / UV-curable adhesive layer / non-curable adhesive layer / release liner].

[0198] Example 2 An optical laminate (sheet for sealing optical semiconductor devices) was fabricated in the same manner as in Example 1, except that a COP film (trade name "ZeonorFilm", manufactured by Zeon Corporation of Japan) was used instead of a polycarbonate film as the substrate layer.

[0199] Example 3 Except that the substrate of the surface treatment layer was changed to an acrylic resin film (trade name "HTX", manufactured by Kaneka Corporation, thickness 40 μm) instead of a TAC film, the optical laminate (sheet for sealing optical semiconductor devices) of Example 3 was made in the same manner as in Example 1.

[0200] Example 4 Except for adjusting the refractive index of the non-curing adhesive layer by material adjustment, the optical laminate (sheet for sealing optical semiconductor devices) of Example 4 was made in the same manner as in Example 1.

[0201] Comparative Example 1 The optical laminate (sheet for sealing optical semiconductor devices) of Comparative Example 1 was made in the same manner as in Example 1, except that a PET film (trade name "Diafoil T100-75S", manufactured by Mitsubishi Chemical Co., Ltd., thickness 75 μm) was used instead of a polycarbonate film as the substrate layer.

[0202] Comparative Example 2 The optical laminate (sheet for sealing optical semiconductor devices) of Comparative Example 2 was made in the same manner as in Example 3, except that a PET film (trade name "Diafoil T100-75S", manufactured by Mitsubishi Chemical Co., Ltd., thickness 75 μm) was used instead of a polycarbonate film as the substrate layer.

[0203] Comparative Example 3 The optical laminate (sheet for sealing optical semiconductor devices) of Comparative Example 3 was fabricated in the same manner as in Example 4, except that a PET film (trade name "Diafoil T100-75S", manufactured by Mitsubishi Chemical Co., Ltd., thickness 75 μm) was used instead of a polycarbonate film as the substrate layer. <Evaluation> The optical laminates obtained in the Examples and Comparative Examples were evaluated as follows. The results are shown in Table 1.

[0204] (1) Refractive index: The refractive index of each surface treatment layer and substrate layer used or fabricated in the Examples and Comparative Examples was measured at (550) nm using a refractive index measuring device (trade name "Prism Coupler Model 2010 / M", manufactured by Metricon Corporation). For the adhesive layer (substrate-free double-sided adhesive sheet) in each example, the refractive index was measured using an Abbe refractometer (trade name "DR-M4", manufactured by ATAGO Corporation) at a measurement wavelength of 589 nm and a measurement temperature of 25°C. For the UV-curable adhesive layer, a laminate formed by sandwiching the UV-curable adhesive layer with two release liner was prepared, and the UV-curable adhesive layer was cured by UV irradiation under the UV irradiation conditions described later for the front reflectance, and the obtained adhesive layer was measured.

[0205] (2) A frontal reflectance of 40.34% with metal wiring printed on an acrylic resin board was used as a substitute for an organic EL device. Then, the release liner of the optical laminate obtained in the Examples and Comparative Examples was peeled off to expose the adhesive layer. The exposed adhesive layer was then attached to the aforementioned organic EL device substitute, and ultraviolet irradiation was performed under the following ultraviolet irradiation conditions to harden the ultraviolet-curable adhesive layer, thereby producing a test sample. Subsequently, the frontal reflectance of the surface treatment layer side surface of the test sample was measured using a spectrophotometer (trade name "CM2600D", manufactured by Konica Minolta) according to the method of JIS Z8722. <Ultraviolet Irradiation Conditions> Ultraviolet Irradiation Apparatus: Trade name "UM810", manufactured by Nitto Seiki Co., Ltd. Light Source: High-pressure mercury lamp Irradiation Intensity: 50 mW / cm2 (Measuring Machine: Trade name "UT-101 Ultraviolet Illuminometer", manufactured by Ushio Electric Co., Ltd.) Irradiation Time: 100 seconds Cumulative Light Intensity: 5000 mJ / cm2

[0206] (3) Brightness: The brightness of the test sample prepared in (2) above was measured using a viewing angle characteristic evaluation device (trade name "EZ-Contract160D", manufactured by ELDIM) from the surface treatment layer side surface under white light illumination. Based on the measurement data, the average value of the data obtained by deflecting the azimuth angle by 15° when the polar angle is 0° was taken as the front brightness, and the average value of the data obtained by deflecting the azimuth angle by 15° when the polar angle is 45° was taken as the oblique brightness at 45°. The values ​​were calculated.

[0207] (4) The phase difference of the substrate layer was measured at 23°C using a product called "AxoAcan" (manufactured by Axometrics) for the substrate layer used in the examples and comparative examples.

[0208] (5) Color difference: For the test samples prepared in (2) above, check whether the appearance is not visible when the polar angle and azimuth angle are deflected from the surface of the surface treatment layer. If no unevenness is detected, it is rated as ○. If the appearance is not visible but there is no problem with the quality, it is rated as △. If there is a problem with the quality, it is rated as ×.

[0209] ◎[Table 1] Table 1 Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Refractive index Surface treatment layer 1.49 1.49 1.51 1.49 1.49 1.53 1.49 Adhesive layer 1.49 1.49 1.49 1.49 1.49 1.49 1.49 Substrate layer 1.51 1.53 1.51 1.51 1.61 1.61 1.61 Hardened adhesive layer 1.48 1.48 1.48 1.48 1.48 1.48 1.48 Non-hardening adhesive layer 1.48 1.48 1.48 1.53 1.48 1.48 1.53 Frontal reflectance (%) 2.98 3.01 3.06 3.05 3.3 3.31 3.39 Diagonal (45°) / Front-facing brightness 0.986 0.978 0.983 0.985 0.931 0.933 0.941 Phase difference (nm) 7 2 5 2 3561 3926 4261 Hue difference ○ ○ ○ ○ △ △ △

[0210] As shown in Table 1, the optical laminate of the present invention (example) is evaluated as follows: the refractive index difference between the substrate layer in the substrate portion and the layer adjacent to the substrate layer, or at least one other layer included in the optical laminate, is 0.05 or less, the reflectivity is reduced, the phase difference and hue difference are also smaller, interlayer reflection is reduced, and color shift is suppressed.

[0211] On the other hand, when the refractive index difference between the substrate layer in the substrate portion and the layer adjacent to the substrate layer or other layers constituting the optical laminate exceeds 0.05 (Comparative Examples 1 to 3), the reflectivity and hue difference increase compared to the Examples, causing interlayer reflection and confirming color shift. [Simplified Explanation of the Diagram]

[0019] FIG1 is a cross-sectional view showing one embodiment of the optical stack of the present invention. FIG2 is a cross-sectional view of an optical semiconductor device using the optical stack shown in FIG1. ​​FIG3 is an external view showing one embodiment of an optical semiconductor device fabricated by tiling the optical semiconductor device shown in FIG2. FIG4 is a cross-sectional view showing the stacking step in one embodiment of the manufacturing method of the optical semiconductor device. FIG5 is a cross-sectional view of the stack obtained after the stacking step shown in FIG4. FIG6 is a cross-sectional view of the stack obtained by performing a hardening step on the stack shown in FIG5. FIG7 is a cross-sectional view showing the cutting position in the cutting step of the stack shown in FIG6.

Claims

1. An optical laminate comprising a surface treatment layer, a substrate portion, and an adhesive layer disposed on at least one side of the substrate portion, and used in a photonic semiconductor element, wherein when the optical laminate is bulk-laminated in the photonic semiconductor element, the substrate portion is located on the photonic semiconductor element side relative to the surface treatment layer, the surface treatment layer is a layer that imparts anti-reflective and / or anti-glare properties to the optical laminate, the refractive index of the substrate layer in the substrate portion is 1.43 to 1.55, the refractive index difference between the substrate layer in the substrate portion and all other layers included in the optical laminate is 0.05 or less, and the optical laminate has a configuration of [substrate layer / first adhesive layer / second adhesive layer].

2. The optical laminate of claim 1, wherein the phase difference of the substrate layer is less than 20 nm.

3. The optical laminate as claimed in claim 1 or 2, wherein when the side of the optical laminate with the substrate portion opposite to the side with the surface treatment layer is bonded to a sheet with a surface reflectance of 40.34% and the measurement is performed, the ratio of the 45° brightness measured at an oblique angle of 45° to the front brightness measured in the vertical direction from the front [45° brightness / front brightness] is 0.95 to 1.

0.

4. The optical laminate of claim 1 or 2, wherein when the side of the optical laminate having the substrate portion opposite to the side having the surface treatment layer is bonded to a sheet with a surface reflectance of 40.34% and the measurement is performed, the front reflectance is 3.2% or less.

5. An optical semiconductor device comprising a substrate, an optical semiconductor element disposed on the substrate, and an optical laminate of claim 1 or 2 deposited on the optical semiconductor element.

6. The optical semiconductor device as described in claim 5 is a self-emissive display device.

7. An image display device comprising a self-emissive display device as claimed in claim 6.

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