Optical stack

Abstract

This invention provides an optical laminate for use in optical semiconductor devices, which is environmentally friendly. The optical laminate 1 comprises a surface treatment layer 4, a substrate portion 2, and adhesive layers 3a and 3b disposed on at least one side of the substrate portion 2, and is used in an optical semiconductor device 7. When the optical laminate 1 is deposited on the optical semiconductor device 7, the substrate portion 2 is located on the optical semiconductor device 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 substrate portion 2 has a substrate layer with a biomass of 30% or more.

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] For example, a backlight device used in a known liquid crystal display device has the following structure: a plurality of LEDs are disposed on a substrate, and the plurality of LEDs are sealed with a sealing resin. A known method for sealing the plurality of LEDs together using the sealing resin is a method using a sealing sheet having a sealing layer for overlapping the area where the plurality of LEDs are disposed to seal the LEDs (see, for example, Patent Document 1). [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2019 / 225761 [Summary of the Invention]

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

[0005] In recent years, Sustainable Development Goals (SDGs) have been established worldwide as a means to achieve them, and the problem-solving process of ESG (Environmental, Social, and Governance) has received attention. Therefore, in the operation or growth of enterprises, it is necessary to consider these three aspects, and ESG is increasingly recognized as a corporate social responsibility.

[0006] This invention was conceived based on the above circumstances, and its object is to provide an optical multilayer, which is a multilayer used for deposition on optical semiconductor devices and is environmentally friendly. [Technical Means for Solving the Problem]

[0007] In order to achieve the above-mentioned objectives, the inventors have conducted research and discovered that, based on an optical laminate having a specific laminate structure and using a substrate layer with high biomass in the substrate portion, an optical laminate that can be used as a laminate in an optical semiconductor device and is environmentally friendly can be obtained. The present invention was made based on these insights.

[0008] That is, 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 substrate portion has a substrate layer with a biomass of 30% or more.

[0009] As described above, the optical laminate includes a substrate portion having a substrate layer with a biomass of 30% or more. Therefore, the optical laminate is environmentally friendly.

[0010] Preferably, the substrate layer comprises a polycarbonate-based resin. If the substrate layer is a polycarbonate substrate, the substrate portion has higher rigidity, and the operability of the optical laminate is excellent. Furthermore, it is relatively easy to obtain a substrate layer with a biomass of 30% or more.

[0011] The tensile modulus of the substrate layer is preferably 1.5 to 3.5 GPa. If the tensile modulus is 1.5 GPa or higher, the substrate layer has moderate 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 layer has moderate flexibility, and when the optical semiconductor element is a protrusion and the gap between multiple optical semiconductor elements is a concave portion, the optical multilayer has excellent conformability to the protrusions and concavities, and the embedding of the optical semiconductor element is excellent.

[0012] The refractive index of the substrate layer is preferably 1.43 to 1.55. If the refractive index is within the above range, there is a tendency for the refractive index difference with the other layers constituting the optical stack 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.

[0013] Furthermore, the present invention provides an optical semiconductor device comprising a substrate, an optical semiconductor element disposed on the substrate, and an optical laminate deposited on the optical semiconductor element. By having a substrate portion having a substrate layer with a biomass of 30% or more, this optical semiconductor device is environmentally friendly.

[0014] The above-mentioned optical semiconductor device may also be a self-emissive display device.

[0015] Furthermore, the present invention provides an image display device comprising the above-described self-emissive display device. [Effects of the Invention]

[0016] The optical laminate of the present invention is environmentally friendly. Therefore, by using the above-described optical laminate, it is possible to help achieve the SDGs.

Implementation Method

[0018] [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.

[0019] When the optical multilayer 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 multilayer 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 laminated.

[0020] 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.

[0021] 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 serves as a protective material for the optical laminate and is peeled off when the optical laminate is used. The release liner is, for example, attached to the adhesive layer located on the surface of the optical laminate and is peeled off when the optical laminate is used. Furthermore, it is not necessary to provide a release liner.

[0022] 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.

[0023] 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, an adhesive layer 3a, a substrate portion 2, another adhesive layer 3b, and a release liner 5.

[0024] (Substrate portion) The aforementioned substrate portion serves as a support in the aforementioned optical stack, thereby improving the operability of the aforementioned optical stack. Furthermore, the substrate layer used in the substrate portion is the part that is attached to the substrate containing the optical semiconductor element together with the adhesive layer when the optical stack is applied to the optical semiconductor element. The release liner that is peeled off during the use of the optical stack (during attachment) or the surface protective film used only to protect the surface of the substrate portion is not included in the "substrate portion".

[0025] The aforementioned substrate portion has at least a substrate layer with a biomass content of 30% or more. Furthermore, in this specification, the substrate layer with a biomass content of 30% or more is sometimes referred to as a "biomass substrate layer". The aforementioned substrate portion may be a single layer, or it may be multiple identical layers, or multiple layers with different compositions or thicknesses. When the aforementioned substrate portion includes multiple substrate layers, the multiple substrate layers may consist solely of a biomass substrate layer, or they may include a biomass substrate layer and other substrate layers.

[0026] By having a biomass substrate layer as the substrate, the aforementioned optical laminate is environmentally friendly. The biomass content of the aforementioned biomass substrate layer is calculated as the mass ratio of the biomass-derived components to the total amount (100% by mass) of the resin components constituting the aforementioned biomass substrate layer.

[0027] The tensile modulus of the aforementioned biomaterial substrate layer 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 aforementioned biomaterial substrate layer has appropriate hardness, and when the aforementioned 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 aforementioned substrate layer has appropriate flexibility, and when the optical semiconductor element is provided as a protrusion and the gap between the plurality of optical semiconductor elements is provided as a concave portion, the aforementioned optical multilayer has excellent conformability to the protrusions and concavities, and the embedding of the optical semiconductor element is excellent.

[0028] The refractive index of the above-mentioned biomass substrate layer is preferably 1.43 to 1.55, and more preferably 1.48 to 1.53. If the above-mentioned refractive index is within the above-mentioned range, there is a tendency for the refractive index difference with other layers constituting the above-mentioned optical laminate (such as substrate layers other than the above-mentioned biomass substrate layer constituting the above-mentioned substrate portion or the above-mentioned adhesive layer, etc.) 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.

[0029] The phase difference of the aforementioned biomass substrate layer 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 aforementioned phase difference is 20 nm or less (especially 10 nm or less), the generation of iris-like unevenness is suppressed even when polarized light passes through, resulting in excellent visibility when applied to an image display device.

[0030] The frontal reflectance of the above-mentioned biomass substrate layer is preferably 5% or less, more preferably 4.8% or less, and even more preferably 4.5% or less. If the frontal reflectance is 5% or less, color shift is less likely to occur when the above-mentioned optical laminate is applied to an image display device, and an image display device with stable appearance and improved visibility can be provided when viewing the screen from any direction.

[0031] The elongation at break of the aforementioned biomaterial substrate layer 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 irregularities 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.

[0032] Examples of the substrate layers constituting the above-mentioned substrate portion (the above-mentioned biomass substrate layer 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 (EVA), ethylene-propylene copolymers, cyclic olefin polymers, ethylene-butene copolymers, ethylene-hexene copolymers, etc. Polyolefin resins; polyurethanes; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PET), and polybutylene terephthalate (PBT); polycarbonate resins; polyimide resins; polyetheretherketone (PEEK); polyetherimide (PEM); aromatic polyamines and fully aromatic polyamines; polyphenylene sulfide (PPS); fluoropolymers; polyvinyl chloride (PVC); polyvinylidene chloride (PVDC); cellulose resins such as triacetin (TAC); silicone resins; acrylic resins such as polymethyl methacrylate (PMMA); polyurethane; polyarylates; polyvinyl acetate, etc. Only one of the above resins may be used, or two or more may be used.

[0033] Preferably, the aforementioned biomass substrate layer is a layer containing a polycarbonate-based resin, i.e., a polycarbonate substrate. If the aforementioned biomass substrate layer is a polycarbonate substrate, the rigidity of the substrate portion is higher, and the operability of the aforementioned optical laminate is more excellent. Furthermore, it is relatively easy to obtain a substrate layer with a biomass content of 30% or more.

[0034] 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.

[0035] The aforementioned dihydroxy compound can be exemplified as a known or commonly used dihydroxy compound constituting a polycarbonate resin. When the aforementioned biomass substrate layer 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. Since isosorbide can be manufactured using sorbitol derived from plants, a polycarbonate resin with a higher biomass can be easily manufactured. Furthermore, compared to conventional polycarbonate resins using dihydroxy diaryl compounds, it exhibits superior UV resistance. Also, due to its amorphous tendency, it exhibits superior surface conformability compared to crystalline resins such as PET.

[0036] 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.

[0037] 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.

[0038] The thickness of the above-mentioned biomass substrate layer 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.

[0039] 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.

[0040] 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.

[0041] (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.

[0042] Preferably, the adhesive layer is provided at least on the side opposite to the side where the optical semiconductor element is deposited (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.

[0043] Alternatively, the adhesive layer may be provided on the side of the substrate portion having the surface treatment layer (i.e., the side opposite to the side of the optical semiconductor element stack). When the surface treatment layer is a surface treatment stack body described later, the substrate portion and the surface treatment stack body can be bonded together via the adhesive layer.

[0044] 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.

[0045] When the adhesive layer is composed of multiple layers on one side of the substrate portion where an optical laminate exists, the adhesive layer preferably includes a curable adhesive layer (curable adhesive layer) and a non-curable adhesive layer (non-curable adhesive layer). Examples of the curable adhesive layer include an adhesive layer that cures upon exposure to radiation (radiation-curable adhesive layer) and an adhesive layer that cures upon exposure to heat (thermo-curable adhesive layer). Examples of radiation include active energy lines such as electron beams, ultraviolet light, alpha rays, beta rays, gamma rays, and X-rays. Ultraviolet light is preferred.

[0046] 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.

[0047] 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 irradiation, etc., reducing the adhesion of the sealing sheet side. Consequently, the adhesion between adhesive layers in adjacent optical semiconductor devices in a flat state is low, and when adjacent optical semiconductor devices are pulled apart, sheet defects or adhesion between adjacent optical semiconductor devices are less likely to occur. Moreover, when an optical laminate is bulk-laminated onto an optical semiconductor device to fabricate an optical semiconductor device and subsequently cut, the stickiness of the cut portion can be suppressed, resulting in the fabrication of an optical semiconductor device with a good appearance.

[0048] 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.

[0049] The aforementioned colorant is preferably a black colorant. The aforementioned black colorant may be any known or commonly used colorant (pigment, dye, etc.) for producing a black color. 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 colorants of colors other than black.

[0050] 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.

[0051] The refractive index of the aforementioned 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 aforementioned range, there is a tendency for the refractive index difference with that of other layers constituting the aforementioned optical laminate (such as the aforementioned biomaterial substrate layer and other layers constituting the aforementioned substrate portion) to decrease, thereby reducing the reflectivity at the interface, resulting in excellent visibility of the optical semiconductor device and reducing the likelihood of color shift. Furthermore, the refractive index of the aforementioned adhesive layer is a value under the operating conditions of the optical laminate, and when the aforementioned adhesive layer includes a curable adhesive layer, it is a value under the condition that the curable adhesive layer has been cured.

[0052] 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.

[0053] (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. Examples of the anti-glare layer include an anti-glare treatment layer. Examples of the anti-reflective layer include 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.

[0054] 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 biomass substrate layer). The anti-glare treatment and anti-reflection treatment can be performed using known or conventional methods.

[0055] 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 biomaterial substrate layer, 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.

[0056] 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 (such as the above-mentioned biomass substrate layer 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, 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.

[0057] 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.

[0058] (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.

[0059] 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.

[0060] 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.

[0061] (Optical Stack) In the above-described optical stack, the refractive index difference between the biomass substrate layer and the layer adjacent to the biomass 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 is 0.05 or less, when the above-described optical stack is applied to an image display device, interlayer reflection between the biomass substrate layer and the layer adjacent to the biomass substrate layer can be reduced. As a result, the light extraction efficiency of the optical semiconductor device is excellent due to the reduced interlayer reflectivity, and color shift can be suppressed. Furthermore, it is preferable that at least one of the two layers adjacent to the biomass substrate layer has a refractive index difference with the biomass substrate layer within the above-described range, and more preferably that the refractive index differences between both layers and the biomass substrate layer are within the above-described range. Furthermore, the refractive index of the aforementioned adjacent layer is the value under the operating conditions of the optical laminate. When the aforementioned adjacent layer is a hardening layer (hardening layer) such as a hardening adhesive layer, it is the value under the hardened state of the hardening layer.

[0062] The refractive index difference between the aforementioned biomaterial substrate layer and at least one other layer included in the aforementioned optical stack 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 is 0.05 or less, when the aforementioned optical stack is applied to an image display device, light reflection between the biomaterial substrate layer and the aforementioned other 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, it is preferable that the refractive index difference between the aforementioned biomaterial substrate layer and all other layers included in the aforementioned optical stack is within the aforementioned range. Moreover, the refractive index of the aforementioned other layers is a value under the operating state of the optical stack, and when the aforementioned other layers are hardening layers (hardening layers) such as hardening adhesive layers, it is a value under the hardened state of the hardening layer.

[0063] The refractive index difference between the biomaterial substrate layer 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 laminate is applied to an image display device, light reflection between the biomaterial substrate layer 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 biomaterial substrate layer and at least one adhesive layer is within the above range. Preferably, the refractive index difference between the biomaterial substrate layer and all adhesive layers in the optical laminate is within the above range. Furthermore, the refractive index of the adhesive layer is the value under the operating state of the optical laminate. When the adhesive layer includes a curable adhesive layer, it is the value under the curable adhesive layer's cured state.

[0064] The refractive index difference between the biomaterial substrate layer 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 biomaterial substrate layer 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.

[0065] In the aforementioned optical laminate, the ratio of the brightness measured at a 45° angle 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 higher (e.g., 0.95 to 1.0), more preferably 0.97 or higher, and even more preferably 0.98 or higher. If the ratio is 0.95 or higher, when the aforementioned 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 aforementioned ratio is a value under the operating state of the optical laminate, and in the case where the aforementioned optical laminate has a hardened layer, for example, it is a value under the state where that layer has been hardened.

[0066] 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, more preferably 3.1% or less. If the frontal reflectance is 3.2% or less, when the above-described optical laminate is applied to an image display device, an image display device that prevents reduced visibility due to reflection of external light or image projection and adjusts its appearance can be provided. Furthermore, the above-described frontal reflectance is a value of the optical laminate in its usage state, and in the case where the optical laminate has a hardened layer, for example, it is a value of the layer in its hardened state.

[0067] 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 biomass substrate layer constituting 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 (biomass substrate layer) 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 to form a laminate.

[0068] 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.

[0069] On one 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 solvent removal 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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 an optical semiconductor device" means embedding at least a portion of the optical semiconductor device into the adhesive layer provided with the optical stack.

[0074] 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.

[0075] 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.

[0076] [Optical Semiconductor Device] An optical semiconductor device can be fabricated using the optical multilayer of the present invention. The optical semiconductor device fabricated 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.

[0077] Examples of the aforementioned light semiconductor devices include blue light-emitting diodes, green light-emitting diodes, red light-emitting diodes, ultraviolet light-emitting diodes, and other light-emitting diodes (LEDs).

[0078] 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.

[0079] 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 hardening resin layer, by means of radiation 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.

[0080] 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-mentioned optical semiconductor device is not limited to this form, and may also be in the form in which 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'.

[0081] As described above, the aforementioned optical semiconductor device includes a biomaterial substrate layer as the substrate layer in the optical stack. Therefore, the aforementioned optical semiconductor device has a high degree of biocompatibility and is environmentally friendly.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] The optical laminate 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.

[0087] 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.

[0088] [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.

[0089] 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.

[0090] (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 facing the substrate 6 in the lamination step is larger than the area of ​​the substrate 6 facing the optical laminate 1 in the lamination step.

[0091] 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.

[0092] (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.

[0093] (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.

[0094] (Laying Step) In the above-described laying step, a plurality of optical semiconductor devices obtained in the above-described 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]

[0095] 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.

[0096] Example 1 <Anti-reflective layer / anti-glare layer / TAC film> (Anti-glare layer) 40 parts by weight of UV-curable urethane acrylate resin (trade name "NK OLIGO UA-53H-80BK", manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), which is included as the resin forming material of the anti-glare layer; 57.5 parts by weight of multifunctional acrylate (trade name "Viscoat#300", manufactured by Osaka Organic Chemical Industry Co., Ltd.), which is 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 (trade name "Opstar Z7540", manufactured by JSR Co., Ltd.); 2.8 parts by weight of silicone particles (trade name "Tospearl 130ND", manufactured by Momentive Performance Materials Japan LLC); and thixotropic organic clay, namely synthetic bentonite (trade name "Sumecton SAN", Kunimine), which is used as a thixotropic agent. The following mixture was prepared: 2.5 parts by weight of an anti-glare coating material (coating solution) manufactured by Industries Co., Ltd.; 3 parts by weight of a photopolymerization initiator (trade name "OMNIRAD907", manufactured by BASF); 6.5 parts by weight of crosslinked acrylic-styrene copolymer microparticles (trade name "SSX-103DXE", manufactured by Sekisui Chemicals Co., Ltd.); and 0.1 parts by weight of a leveling agent (trade name "LE-303", manufactured by Kyoei Chemical Co., Ltd.). Furthermore, the above-mentioned organoclay was diluted with toluene to a solid content of 6% by weight. The mixture was diluted with a toluene / cyclopentanone mixed solvent (mass ratio 64 / 36) to a solid content concentration of 38% by weight, and an anti-glare coating material (coating solution) was prepared using an ultrasonic disperser.

[0097] 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 a TAC film with an anti-glare layer thickness of 6.5 μm on its surface.

[0098] (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 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.

[0099] The anti-reflective layer forming material 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 for curing. 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.

[0100] <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 before adding ethyl acetate to obtain an acrylic polymer solution with a solid content concentration of 30% 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.

[0101] <Polycarbonate film / UV-curable adhesive layer / non-curable adhesive layer> (UV-curable adhesive layer) In a 1 L round-bottom separable flask, 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 of methyl ethyl ketone) as a polymerization solvent were added to a polymerization apparatus 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. The mixture was stirred and simultaneously purged with nitrogen at room temperature for 6 hours. Subsequently, polymerization was carried out under nitrogen flow, stirring, and maintained at 65°C for 4 hours, followed by maintaining at 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% 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 of 20-40% by weight using toluene as a diluent to obtain an adhesive solution (1).

[0102] 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).

[0103] Next, using a manual roller to bond 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 together without air bubbles, forming one 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.

[0104] (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 polymerization apparatus consisting of a 1 L round-bottom separable flask equipped with a separable cover, 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% by mass) were mixed with 100 parts by mass of the solid content of the base polymer. The solution was adjusted to a solid content of 20-40% by mass using toluene as a diluent to obtain an adhesive solution (2).

[0105] 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.

[0106] (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.

[0107] <Optical Stacked Body (Sheet for Sealing Optical Semiconductor Components)> A release liner is peeled off from a stacked body having a [anti-reflective layer / anti-glare layer / TAC film / adhesive layer / release liner] layer structure. Using a hand roller, the exposed adhesive layer is bonded to the polycarbonate film surface of the stacked body having a [polycarbonate film / UV-curable adhesive layer / non-curable adhesive layer / release liner] layer structure in a bubble-free manner. Subsequently, it is cured at 50°C for 48 hours to produce the optical stacked body (sheet for sealing optical semiconductor components) of Example 1, which has the 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].

[0108] Example 2 A polycarbonate film with a thickness of 70 μm was made from the polycarbonate resin (trade name "DURABIO T7450A" (different batches), manufactured by Mitsubishi Chemical Co., Ltd.) of the biomass shown in Table 1 by extrusion as the substrate layer. An acrylic film (trade name "HTX", manufactured by Kaneka Co., Ltd., thickness 40 μm) was used instead of the TAC film. Otherwise, the optical laminate (sheet for sealing optical semiconductor devices) of Example 2 was made in the same manner as in Example 1.

[0109] Example 3 A polycarbonate film with a thickness of 70 μm was made from the polycarbonate resin (trade name "DURABIO T7450A" (different batches), manufactured by Mitsubishi Chemical Co., Ltd.) of the quality shown in Table 1 by extrusion as a substrate layer. The refractive index was adjusted by adjusting the composition of the non-curing adhesive layer. Otherwise, the optical laminate (sheet for sealing optical semiconductor devices) of Example 4 was made in the same manner as in Example 1.

[0110] 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.

[0111] 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 2, 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.

[0112] Comparative Example 3 The optical laminate (sheet for sealing optical semiconductor devices) of Comparative Example 3 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.

[0113] <Evaluation> The optical laminates obtained in the Examples and Comparative Examples and each layer constituting the optical laminates were evaluated as follows. The results are shown in the table.

[0114] (1) 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). Furthermore, the refractive index of the adhesive layer 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 frontal reflectance, and the obtained adhesive layer was measured.

[0115] (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. <UV Irradiation Conditions> UV 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 UV Illuminometer", manufactured by Ushio Electric Co., Ltd.) Irradiation Time: 100 seconds Cumulative Light Intensity: 5000 mJ / cm²

[0116] (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) with the white light on, from the surface of the surface treatment layer side surface. 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.

[0117] (4) The phase difference of the substrate layer was measured at 23°C using a product called "AxoAcan" (manufactured by Axometrics).

[0118] (5) Front reflectance of substrate layer The substrate layer used in the examples and comparative examples was bonded to a black acrylic resin board, and the front reflectance of the side surface of the substrate layer was measured using a spectrophotometer (trade name "CM2600D", manufactured by Konica Minolta) according to the method of JIS Z8722.

[0119] (6) Tensile modulus of elasticity and elongation at break of the substrate layer The substrate layer used in the examples and comparative examples was cut into 1 cm wide and 13 cm long. Tensile tests were performed using an Autograph ASG-50D tensile testing machine (manufactured by Shimadzu Corporation) at a tensile speed of 200 mm / min, a clamping distance of 50 mm, and a room temperature (23°C). The tensile modulus of elasticity was then measured.

[0120] (7) Color difference: For the test sample prepared in (2) above, check whether the appearance is uneven when the polar angle and azimuth angle are deflected from the surface of the surface treatment layer. If no unevenness is found, it is rated as ○. If the appearance is uneven but there is no problem with the quality, it is rated as △. If there is a problem with the quality, it is rated as ×.

[0121] ◎[Table 1] (Table 1) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Substrate layer Biomass [%] 35 38 36 0 0 0 Phase difference [nm] 7 5 2 3561 3926 4261 Frontal reflectance [%] 4.14 4.12 4.17 5.21 5.09 5.13 Tensile modulus of elasticity [%] 2.5 2.5 2.5 4.2 4.2 4.2 Elongation at break [%) 5 5 5 16 16 16 Refractive index Surface treatment layer 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 Substrate layer 1.51 1.51 1.51 1.61 1.61 1.61 UV-curable adhesive layer 1.48 1.48 1.48 1.48 1.48 1.48 Non-hardening adhesive layer 1.48 1.48 1.53 1.48 1.48 1.53 Frontal reflectance [%] 2.98 3.06 3.05 3.30 3.31 3.39 [45° angled brightness / frontal brightness] 0.986 0.983 0.985 0.931 0.933 0.941 Hue difference ○ ○ ○ △ △ △

[0122] As shown in Table 1, the optical laminate of the present invention (example) is judged to have a high biomass and is environmentally friendly. Furthermore, the optical laminate is judged to have a low frontal reflectance and excellent chromatic aberration, thus exhibiting excellent performance as an optical laminate. On the other hand, the optical laminate of the comparative example is judged to have a lower biomass, and consequently, its performance as an optical laminate is also inferior. [Simplified Explanation of the Diagram]

[0017] 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, and the substrate portion has a substrate layer with a biomass of 30% or more, the refractive index difference between the substrate layer and the surface treatment layer is 0.10 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 substrate layer comprises a polycarbonate resin.

3. The optical laminate as claimed in claim 1 or 2, wherein the tensile modulus of the substrate layer is 1.5 to 3.5 GPa.

4. The optical laminate as claimed in claim 1 or 2, wherein the refractive index of the substrate layer is 1.43 to 1.

55.

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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