JP2023143639A - Adhesive layer, laminated sheet, adhesive composition, and optical semiconductor device - Google Patents

Abstract

To provide an adhesive layer which has excellent anti-reflection properties when bonded to an adherend and is capable of suppressing unevenness in the brightness of transmitted light.SOLUTION: A laminated sheet 1 is provided with at least an adhesive layer 21. The adhesive layer 21 has a haze value of 61% or more and a total light transmittance of 69% or less. The laminated sheet 1 may be provided with a layer 42 having anti-glare and/or anti-reflective properties on one surface. The thickness of the laminated sheet 1 is preferably 500 μm or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to an adhesive layer. More specifically, the present invention relates to an adhesive layer suitable for sealing optical semiconductor devices such as mini/micro LEDs.

In recent years, self-luminous display devices typified by mini/micro LED display devices (Mini/Micro Light Emitting Diode Displays) have been devised as next-generation display devices. The basic configuration of mini/micro LED display devices is to use a substrate on which many minute optical semiconductor elements (LED chips) are arranged at high density as a display panel, and the optical semiconductor elements are sealed with a sealing material. , a cover member such as a resin film or a glass plate is laminated on the outermost layer.

In a display body including a self-luminous display device such as a mini/micro LED display device, wiring (metal wiring) made of metal or a metal oxide such as ITO is arranged on a substrate of a display panel. Such display devices have a problem in that, for example, when the lights are turned off, light is reflected by the metal wiring and the like, resulting in poor screen appearance and poor design. For this reason, a technique has been adopted that uses an antireflection layer to prevent reflection from metal wiring as a sealing material for sealing an optical semiconductor element.

Furthermore, displays using self-luminous display devices have a problem in that uneven brightness (luminance unevenness) occurs due to the light source of the optical semiconductor element. When brightness unevenness occurs, a phenomenon called "color shift" occurs, in which the color tone changes when the display is viewed from the front and when viewed from an oblique viewing angle.

Patent Document 1 discloses an adhesive film in which an adhesive layer in which carbon black is dispersed is provided on one surface of a transparent base material. Patent Document 2 discloses a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer containing light-diffusing fine particles. Further, Patent Document 3 discloses a colored adhesive sheet including a colored adhesive layer having a haze value of 1% or more and 60% or less.

Japanese Patent Application Publication No. 11-335639 JP2021-138825A Japanese Patent Application Publication No. 2020-164702

However, although the adhesive layers in the adhesive sheets of Patent Documents 1 and 3 are expected to have the effect of preventing reflection from metal wiring when sealing an optical semiconductor element, they do not suppress uneven brightness. Further, although the adhesive layer in the adhesive sheet of Patent Document 2 is expected to have an effect of suppressing brightness unevenness, it did not have antireflection properties. Therefore, there is a need for an adhesive layer that has excellent antireflection properties when bonded to an adherend and is capable of suppressing uneven brightness of transmitted light.

The present invention was devised under these circumstances, and its purpose is to provide excellent antireflection properties when bonded to an adherend and to suppress uneven brightness of transmitted light. The purpose of this invention is to provide an adhesive layer that is capable of

As a result of intensive studies to achieve the above object, the present inventors found that an adhesive layer having a specific haze value and total light transmittance has excellent antireflection properties when bonded to an adherend; It has been found that it is possible to suppress uneven brightness of transmitted light. The present invention was completed based on these findings.

That is, the present invention provides an adhesive layer having a haze value of 61% or more and a total light transmittance of 69% or less.

Further, the present invention provides a laminated sheet including the pressure-sensitive adhesive layer.

The laminated sheet may include a layer having anti-glare and/or anti-reflection properties on one surface.

The thickness of the laminated sheet is preferably 500 μm or less.

The present invention also provides an adhesive composition that contains a colorant and light diffusing fine particles, and has a haze value of 61% or more and a total light transmittance of 69% or less when forming an adhesive layer. I will provide a.

The present invention also provides an optical semiconductor device comprising a substrate, an optical semiconductor element disposed on the substrate, and the laminated sheet or a cured product thereof that seals the optical semiconductor element.

The adhesive layer of the present invention has excellent antireflection properties when bonded to an adherend, and can suppress uneven brightness of transmitted light. Therefore, when an optical semiconductor element is sealed with a laminated sheet provided with the adhesive layer of the present invention, the substrate surface has excellent antireflection properties, and brightness unevenness due to light emitted by the optical semiconductor element is less likely to occur.

FIG. 1 is a cross-sectional view of a sheet for encapsulating an optical semiconductor device according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of a sheet for encapsulating an optical semiconductor device according to another embodiment of the present invention. FIG. 2 is a partial cross-sectional view showing an embodiment of an optical semiconductor device using the optical semiconductor element sealing sheet shown in FIG. 1. FIG. FIG. 3 is a partial cross-sectional view showing an embodiment of an optical semiconductor device using the optical semiconductor element sealing sheet shown in FIG. 2. FIG. FIG. 3 is a partial cross-sectional view showing another embodiment of an optical semiconductor device using the optical semiconductor element sealing sheet shown in FIG. 2. FIG.

[Adhesive layer]
The adhesive layer of the present invention has a haze value of 61% or more and a total light transmittance of 69% or less. The adhesive layer of the present invention is a single-layer adhesive layer. The adhesive layer of the present invention is preferably a resin layer made of resin.

The haze value (initial haze value) of the adhesive layer of the present invention is 61% or more, preferably 70% or more, more preferably 80% or more, even more preferably 90% or more, 95% or more, 97% or more. % or more, or even around 99.9%. When the haze value is 61% or more, uneven brightness of light transmitted through the adhesive layer can be suppressed when bonded to an adherend. Note that the upper limit of the haze value is not particularly limited, and may be 100%.

The total light transmittance of the adhesive layer of the present invention is 69% or less, preferably 60% or less, more preferably 50% or less, still more preferably 40% or less, and still more preferably 30% or less. Further, from the viewpoint of ensuring light transmittance, the above-mentioned total light transmittance is preferably 0.5% or more, more preferably 1% or more, still more preferably 1.5% or more, and still more preferably 2% or more. % or more, more preferably 2.5% or more, particularly preferably 3% or more.

The haze value and total light transmittance above are values for a single layer, respectively, and can be measured by the method specified in JIS K7136 and JIS K7361-1. It can be controlled by the type and amount of the fine particles.

The adhesive layer of the present invention may be a resin layer that has the property of being cured by radiation irradiation (radiation curable resin layer), or a resin layer that does not have the property of being cured by radiation irradiation (radiation non-curable resin layer). It may be. Examples of the radiation include electron beams, ultraviolet rays, α rays, β rays, γ rays, and X rays.

The adhesive layer of the present invention preferably contains a colorant. The colorant may be a dye or a pigment as long as it can be dissolved or dispersed in the adhesive layer of the present invention. Dyes are preferred because they do not have sedimentation properties like pigments and are easy to distribute uniformly. Pigments are also preferred because they provide high color development even when added in small amounts. If a pigment is used as a coloring agent, it is preferably one with low or no electrical conductivity. The above coloring agents may be used alone or in combination of two or more.

As the colorant, a black colorant is preferable. As the black colorant, known or commonly used colorants (pigments, dyes, etc.) for producing a black color can be used. For example, carbon black (furnace black, channel black, acetylene black, thermal black, lamp black, etc.) can be used. , pine smoke, etc.), graphite, copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (non-magnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide , chromium complexes, anthraquinone colorants, zirconium nitride, etc. Further, a colorant that functions as a black colorant by combining a colorant exhibiting a color other than black may be used.

When the adhesive layer of the present invention is a radiation-curable resin layer, the colorant preferably absorbs visible light and has transparency to light at a wavelength at which the radiation-curable resin layer can be cured.

The content of the colorant in the adhesive layer of the present invention is 0.04% by mass based on 100% by mass of the total amount of the adhesive layer of the present invention, from the viewpoint of imparting appropriate antireflection ability to the adherend. The above is preferable, more preferably 0.1% by mass or more, and may be 0.2% by mass or more, or 0.4% by mass or more. Further, the content ratio of the colorant is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less, 0.8% by mass or less, It may be 0.1% by mass or less. The content ratio may be appropriately set depending on the type of colorant, the color tone and light transmittance of the adhesive layer, and the like. The colorant may be added to the composition as a solution or dispersion dissolved or dispersed in a suitable solvent.

The adhesive layer of the present invention preferably contains light-diffusing fine particles. In particular, the adhesive layer of the present invention preferably contains light-diffusing fine particles dispersed in the resin layer. The above-mentioned light-diffusing fine particles may be used alone or in combination of two or more.

The light-diffusing fine particles have an appropriate refractive index difference with the resin that can constitute the adhesive layer of the present invention, and impart diffusion performance to the adhesive layer of the present invention. Examples of the light-diffusing fine particles include inorganic fine particles and polymer fine particles. Examples of the material for the inorganic fine particles include silica, calcium carbonate, aluminum hydroxide, magnesium hydroxide, clay, talc, and metal oxides. Examples of the material of the polymer fine particles include silicone resin, acrylic resin (including polymethacrylate resin such as polymethyl methacrylate), polystyrene resin, polyurethane resin, melamine resin, polyethylene resin, and epoxy resin. .

As the polymer fine particles, fine particles made of silicone resin are preferable. Further, as the inorganic fine particles, fine particles made of metal oxide are preferable. As the metal oxide, titanium oxide and barium titanate are preferable, and titanium oxide is more preferable. By having such a configuration, the adhesive layer of the present invention has excellent light diffusivity, and brightness unevenness is further suppressed. Among the above-mentioned polymer fine particles, fine particles made of silicone resin are particularly preferable. In this case, the color tone is hardly changed by the coloring agent of the adhesive layer, and the color is exhibited stably, and the transparency is excellent.

The shape of the light-diffusing fine particles is not particularly limited, and may be, for example, perfectly spherical, flat, or irregularly shaped.

The average particle diameter of the light-diffusing fine particles is preferably 0.1 μm or more, more preferably 0.15 μm or more, even more preferably 0.2 μm or more, particularly preferably 0. .25 μm or more. Furthermore, from the viewpoint of preventing the haze value from becoming too high and displaying a high-definition image, the average particle diameter of the light-diffusing fine particles is preferably 12 μm or less, more preferably 10 μm or less, and still more preferably 8 μm or less. It is. The average particle diameter can be measured using, for example, a Coulter counter.

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

Difference in refractive index between the light-diffusing fine particles and the adhesive constituting the adhesive layer of the present invention (for example, the resin layer excluding various additives such as colorants and light-diffusing fine particles in the adhesive layer of the present invention) The absolute value of is preferably 0.001 or more, more preferably 0.01 or more, even more preferably 0.02 or more, particularly preferably 0.03 or more, from the viewpoint of reducing brightness unevenness more efficiently. It may be 0.04 or more, or 0.05 or more. Further, the absolute value of the refractive index difference between the light-diffusing fine particles and the resin is preferably 5 or less, more preferably 4 or less, from the viewpoint of preventing the haze value from becoming too high and displaying a high-definition image. More preferably, it is 3 or less.

From the viewpoint of imparting appropriate light diffusing performance to the adhesive layer of the present invention, the content of the light-diffusing fine particles in the adhesive layer of the present invention is determined based on 100 mass of the adhesive constituting the adhesive layer of the present invention. 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, even more preferably 0.1 parts by mass or more, still more preferably 0.15 parts by mass or more, even more preferably 0.6 parts by mass. The amount is at least 1 part by mass, more preferably at least 1 part by mass, may be at least 2 parts by mass, or at least 5 parts by mass, particularly preferably at least 10 parts by mass. In addition, from the viewpoint of preventing the haze value from becoming too high, the content of the light-diffusing fine particles is preferably 80 parts by mass or less, more preferably is 70 parts by mass or less, more preferably 50 parts by mass or less, may be 40 parts by mass or less, 30 parts by mass or less, particularly preferably 20 parts by mass or less.

When the adhesive layer of the present invention is the resin layer, examples of the resin constituting the resin layer include known or commonly used resins, such as acrylic resins, urethane acrylate resins, urethane resins, and rubber-based resins. Resin, epoxy resin, epoxy acrylate resin, oxetane resin, silicone resin, silicone acrylic resin, polyester resin, polyether resin (polyvinyl ether, etc.), polyamide resin, fluorine resin, vinyl acetate/vinyl chloride Examples include copolymers and modified polyolefins. The above resins may be used alone or in combination of two or more.

Moreover, a known or commonly used pressure-sensitive adhesive can be used as the resin. Examples of the above-mentioned adhesives include acrylic adhesives, rubber adhesives (natural rubber-based, synthetic rubber-based, mixtures thereof, etc.), silicone-based adhesives, polyester-based adhesives, urethane-based adhesives, and polyether. Examples include adhesives such as adhesives based on polyamide, polyamide adhesives, and fluorine adhesives. The above adhesives may be used alone or in combination of two or more.

The above-mentioned acrylic resin is a polymer containing a structural unit derived from an acrylic monomer (a monomer component having a (meth)acryloyl group in the molecule) as a polymer structural unit. The above acrylic resins may be used alone or in combination of two or more.

It is preferable that the acrylic resin is a polymer containing the largest mass proportion of structural units derived from (meth)acrylic esters. In addition, in this specification, "(meth)acrylic" represents "acrylic" and/or "methacrylic" (either or both of "acrylic" and "methacrylic"), and the others are the same. .

Examples of the above (meth)acrylic esters include hydrocarbon group-containing (meth)acrylic esters. The above-mentioned hydrocarbon group-containing (meth)acrylic esters include alicyclic esters such as (meth)acrylic acid alkyl esters and (meth)acrylic acid cycloalkyl esters having a linear or branched aliphatic hydrocarbon group. Examples include (meth)acrylic esters having a hydrocarbon group, and (meth)acrylic esters having an aromatic hydrocarbon group such as aryl (meth)acrylic esters. The above hydrocarbon group-containing (meth)acrylic esters may be used alone or in combination of two or more.

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

Among the above-mentioned (meth)acrylic acid alkyl esters, ( Preferred are meth)acrylic acid alkyl esters. When the number of carbon atoms is within the above range, the glass transition temperature of the acrylic resin can be easily adjusted, and the adhesiveness of the resin layer can be made more appropriate.

Examples of the (meth)acrylic ester having an alicyclic hydrocarbon group include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, cyclooctyl (meth)acrylate, etc. (meth)acrylic esters having a monocyclic aliphatic hydrocarbon ring; (meth)acrylic esters having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth)acrylate; ) acrylate, dicyclopentanyloxyethyl (meth)acrylate, tricyclopentanyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl Examples include (meth)acrylic acid esters having three or more aliphatic hydrocarbon rings such as (meth)acrylate.

Examples of the (meth)acrylic ester having an aromatic hydrocarbon group include phenyl (meth)acrylate, benzyl (meth)acrylate, and the like.

The above-mentioned hydrocarbon group-containing (meth)acrylic acid ester preferably includes (meth)acrylic acid alkyl ester having a linear or branched aliphatic hydrocarbon group, and further includes an alicyclic hydrocarbon group. It is more preferable to include a (meth)acrylic acid ester having a group. In this case, the resin layer has a well-balanced adhesiveness and is excellent in conforming to irregularities on the adherend.

In order to properly exhibit the basic properties of the hydrocarbon group-containing (meth)acrylic acid ester, such as tackiness and adhesion to adherends, in the resin layer, it is necessary to The proportion of the hydrocarbon group-containing (meth)acrylic acid ester is preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass, based on the total amount (100% by mass) of all the monomer components. % or more. Further, the above ratio is preferably 95% by mass or less, more preferably 80% by mass or less, from the viewpoint of copolymerizing other monomer components and obtaining the effects of the other monomer components.

The proportion of the (meth)acrylic acid alkyl ester having a linear or branched aliphatic hydrocarbon group in all the monomer components constituting the above acrylic resin is based on the total amount (100% by mass) of all the above monomer components. The content is preferably 30% by mass or more, more preferably 40% by mass or more. Further, the above ratio is preferably 90% by mass or less, more preferably 70% by mass or less.

The proportion of the (meth)acrylic acid ester having an alicyclic hydrocarbon group in all the monomer components constituting the acrylic resin is preferably 1% by mass or more based on the total amount (100% by mass) of all the monomer components. , more preferably 5% by mass or more. Further, the above ratio is preferably 30% by mass or less, more preferably 20% by mass or less.

The above-mentioned acrylic resin may contain other copolymerizable acrylic esters with the above-mentioned hydrocarbon group-containing (meth)acrylic ester for the purpose of introducing the first functional group described below and for the purpose of modifying cohesive force, heat resistance, etc. It may also contain structural units derived from monomer components. Examples of the other monomer components include polar groups such as carboxy group-containing monomers, acid anhydride monomers, hydroxy group-containing monomers, glycidyl group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, and nitrogen atom-containing monomers. Examples include containing monomers. Each of the above other monomer components may be used alone or in combination of two or more.

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

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

Examples of the glycidyl group-containing monomer include glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, and the like.

Examples of the sulfonic acid group-containing monomers include styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acrylamidopropanesulfonic acid. ) Acryloyloxynaphthalene sulfonic acid and the like.

Examples of the phosphoric acid group-containing monomer include 2-hydroxyethyl acryloyl phosphate.

Examples of the nitrogen atom-containing monomer include morpholino group-containing monomers such as (meth)acryloylmorpholine, cyano group-containing monomers such as (meth)acrylonitrile, and amide group-containing monomers such as (meth)acrylamide.

It is preferable that the polar group-containing monomer constituting the acrylic resin includes a hydroxy group-containing monomer. By using a hydroxy group-containing monomer, it is easy to introduce the first functional group described below. In addition, the acrylic resin and the resin layer have excellent water resistance, and are resistant to fogging and have excellent whitening resistance even when used in a high humidity environment.

The hydroxy group-containing monomer is preferably 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate, more preferably 2-hydroxyethyl (meth)acrylate.

In order to properly exhibit the basic properties of the hydrocarbon group-containing (meth)acrylic acid ester, such as tackiness and adhesion to adherends, in the resin layer, all monomer components constituting the acrylic resin ( The proportion of the above-mentioned polar group-containing monomer in 100% by mass is preferably 5 to 50% by mass, more preferably 10 to 40% by mass. In particular, from the viewpoint of improving the water resistance of the resin layer, it is preferable that the proportion of the hydroxy group-containing monomer is within the above range.

Other monomer components mentioned above include vinyl monomers such as caprolactone adducts of (meth)acrylic acid, vinyl acetate, vinyl propionate, styrene, and α-methylstyrene; polyethylene glycol (meth)acrylate, and (meth)acrylic acid; Glycol-based acrylic ester monomers such as polypropylene glycol acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth)acrylate , acrylic acid ester monomers such as alkoxy-substituted hydrocarbon group-containing (meth)acrylates (2-methoxyethyl (meth)acrylate, 3-phenoxybenzyl (meth)acrylate, etc.).

The proportion of the other monomer components in the total monomer components (100% by mass) constituting the acrylic resin is, for example, about 3 to 50% by mass, 5 to 40% by mass, or 10 to 30% by mass. Good too.

The acrylic resin may contain a structural unit derived from a polyfunctional (meth)acrylate copolymerizable with a monomer component constituting the acrylic resin in order to form a crosslinked structure in the polymer skeleton. Examples of the polyfunctional (meth)acrylate include hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, and neopentyl glycol di(meth)acrylate. , pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like. The above polyfunctional monomers may be used alone or in combination of two or more.

In order to properly exhibit the basic properties of the hydrocarbon group-containing (meth)acrylic acid ester, such as tackiness and adhesion to adherends, in the resin layer, all monomer components constituting the acrylic resin ( The proportion of the polyfunctional monomer in 100% by mass) is preferably 40% by mass or less, more preferably 30% by mass or less.

When the resin layer is a radiation-curable resin layer, the resin layer includes, for example, a base polymer and a radiation-polymerizable monomer component or oligomer component having a radiation-polymerizable functional group such as a carbon-carbon double bond. A layer containing a radiation-polymerizable functional group (especially an acrylic resin) as a base polymer, and the like.

Examples of the radiation polymerizable functional group include radiation radical polymerizable groups such as groups containing a carbon-carbon unsaturated bond such as ethylenically unsaturated groups, radiation cationic polymerizable groups, and the like. Examples of the group containing a carbon-carbon unsaturated bond include a vinyl group, a propenyl group, an isopropenyl group, an acryloyl group, a methacryloyl group, and the like. Examples of the radiation cationically polymerizable group include an epoxy group, an oxetanyl group, an oxolanyl group, and the like. Among these, groups containing a carbon-carbon unsaturated bond are preferred, and acryloyl and methacryloyl groups are more preferred. The number of the radiation polymerizable functional groups may be one type or two or more types. The radiation-polymerizable functional group may be located on a side chain of the polymer, in the main chain of the polymer, or at the end of the main chain of the polymer.

The radiation-polymerizable functional group-containing polymer has, for example, a functional group that can cause a reaction between a polymer having a reactive functional group (first functional group) and the first functional group to form a bond. (second functional group) and the compound having the radiation-polymerizable functional group can be produced by a method of reacting and bonding while maintaining the radiation-polymerizability of the radiation-polymerizable functional group. Therefore, the polymer having the radiation polymerizable functional group has a structural part derived from the polymer having the first functional group, and a structural part derived from the compound having the second functional group and the radiation polymerizable functional group. It is preferable to include.

Combinations of the first functional group and the second functional group include, for example, a carboxy group and an epoxy group, an epoxy group and a carboxy group, a carboxyl group and an aziridyl group, an aziridyl group and a carboxy group, a hydroxy group and an isocyanate group, Examples include isocyanate groups and hydroxy groups. Among these, a combination of a hydroxy group and an isocyanate group, and a combination of an isocyanate group and a hydroxy group are preferred from the viewpoint of ease of tracking the reaction. The above combination may be one type or two or more types.

Examples of the compound having the radioactive polymerizable functional group and isocyanate group include methacryloyl isocyanate, 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate (MOI), m-isopropenyl-α,α-dimethylbenzyl isocyanate, and the like. It will be done. The above compounds may be used alone or in combination of two or more.

The content of the structural part derived from the second functional group and the compound having a radiation-polymerizable functional group in the acrylic resin having a radiation-polymerizable functional group promotes the curing of the radiation-curable resin layer. From the viewpoint that it can be used, it is preferably 0.5 mol or more, more preferably 1 mol or more, and even more preferably 3 mol, based on 100 mol of the total amount of structural parts derived from the acrylic resin having the first functional group. The amount is particularly preferably 10 moles or more. The above content is, for example, 100 mol or less.

The molar ratio [second functional group/first functional group] of the second functional group to the first functional group in the acrylic resin having the radiation-curable functional group is the radiation-curable resin From the viewpoint of being able to further progress the curing of the layer, it is preferably 0.01 or more, more preferably 0.05 or more, even more preferably 0.2 or more, and particularly preferably 0.4 or more. Further, the molar ratio is preferably less than 1.0, more preferably 0.9 or less, from the viewpoint of further reducing the amount of low molecular weight substances in the radiation-curable resin layer.

The above-mentioned acrylic resin can be obtained by polymerizing the various monomer components mentioned above. This polymerization method is not particularly limited, and includes, for example, a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a polymerization method using active energy ray irradiation (active energy ray polymerization method), and the like. Further, the acrylic resin obtained may be a random copolymer, a block copolymer, a graft copolymer, or the like.

The above-mentioned acrylic resin having a radiation polymerizable functional group can be produced, for example, by polymerizing (copolymerizing) a raw material monomer containing a monomer component having a first functional group to obtain an acrylic resin having a first functional group. , a compound having the second functional group and a radiation-polymerizable functional group can be produced by a method of subjecting an acrylic resin to a condensation reaction or an addition reaction while maintaining the radiation-polymerizability of the radiation-polymerizable functional group. .

Various common solvents may be used in polymerizing the monomer components. Examples of the solvent 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; cyclohexane and methylcyclohexane. alicyclic hydrocarbons; organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. The above solvents may be used alone or in combination of two or more.

The polymerization initiator, chain transfer agent, emulsifier, etc. used in the radical polymerization of the monomer components are not particularly limited and can be appropriately selected and used. The weight average molecular weight of the acrylic resin can be controlled by the amounts of the polymerization initiator and chain transfer agent used and the reaction conditions, and the amounts used are adjusted as appropriate depending on the types of these.

As the polymerization initiator used for polymerizing the monomer components, a thermal polymerization initiator, a photopolymerization initiator (photoinitiator), etc. can be used depending on the type of polymerization reaction. The above polymerization initiators may be used alone or in combination of two or more.

The thermal polymerization initiator is not particularly limited, but includes, for example, an azo polymerization initiator, a peroxide polymerization initiator, a redox polymerization initiator, and the like. The amount of the thermal polymerization initiator used is preferably 1 part by mass or less, more preferably 0 parts by mass or less, based on 100 parts by mass of all the monomer components constituting the first acrylic resin having a functional group. The amount is .005 to 1 part by weight, more preferably 0.02 to 0.5 part by weight.

Examples of the photopolymerization initiators include benzoin ether photopolymerization initiators, acetophenone photopolymerization initiators, α-ketol photopolymerization initiators, aromatic sulfonyl chloride photopolymerization initiators, and photoactive oxime photopolymerization initiators. Initiator, benzoin-based photoinitiator, benzyl-based photoinitiator, benzophenone-based photoinitiator, ketal-based photoinitiator, thioxanthone-based photoinitiator, acylphosphine oxide-based photoinitiator, titanocene-based photoinitiator Examples include photopolymerization initiators. Among these, acetophenone photopolymerization initiators are preferred.

Examples of the acetophenone photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, 4-(t-butyl ) dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1 -one, methoxyacetophenone, etc.

The amount of the photopolymerization initiator used is preferably 0.005 to 1 part by mass, more preferably 0.01 to 0 parts by mass, based on 100 parts by mass of all monomer components constituting the acrylic resin. .7 parts by weight, more preferably 0.18 to 0.5 parts by weight. When the amount used is 0.005 parts by mass or more (particularly 0.18 parts by mass or more), the molecular weight of the acrylic resin can be easily controlled to be small, and the unevenness followability of the resin layer tends to be better.

The reaction between the acrylic resin having the first functional group and the compound having the second functional group and the radiation-polymerizable functional group can be carried out, for example, by stirring in a solvent in the presence of a catalyst. Examples of the above-mentioned solvent include those mentioned above. The above catalyst is appropriately selected depending on the combination of the first functional group and the second functional group. The reaction temperature in the above reaction is, for example, 5 to 100°C, and the reaction time is, for example, 1 to 36 hours.

The acrylic resin may have a structure derived from a crosslinking agent. For example, the acrylic resin can be crosslinked to further reduce the amount of low molecular weight substances in the resin layer. Moreover, the weight average molecular weight of the acrylic resin can be increased. In addition, when the above-mentioned acrylic resin has a radiation-polymerizable functional group, the above-mentioned crosslinking agent may be used to connect functional groups other than the radiation-polymerizable functional group (for example, between first functional groups, between first functional groups, between second functional groups, or between first functional groups). The first functional group and the second functional group are crosslinked. The above crosslinking agents may be used alone or in combination of two or more.

Examples of the crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, and metal salt crosslinking agents. Examples include crosslinking agents, carbodiimide crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, amine crosslinking agents, silicone crosslinking agents, and silane crosslinking agents. Among the above-mentioned crosslinking agents, from the viewpoint of excellent adhesion to optical semiconductor devices and the viewpoint of fewer impurity ions, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred, and isocyanate-based crosslinking agents are more preferred.

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

The content of the structural parts derived from the crosslinking agent is not particularly limited, but it may be contained in 5 parts by mass or less per 100 parts by mass of the acrylic resin, excluding the structural parts derived from the crosslinking agent. It is preferably 0.001 to 5 parts by weight, and even more preferably 0.01 to 3 parts by weight.

The resin layer may contain other components other than the above-mentioned components as long as the effects of the present invention are not impaired. Other ingredients listed above include curing agents, crosslinking accelerators, tackifying 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, granular materials, foil-like materials, etc. Can be mentioned. The above-mentioned other components may be used alone or in combination of two or more.

The adhesive layer of the present invention has L ^* ( in L ^* a ^* b ^* (SCI)) when measured under conditions of a 10° field of view from the adhesive layer side and a light source of D65 in a state where the adhesive layer is bonded to an aluminum foil. L*(SCE) in SCI) and/or L ^* a ^* b ^* (SCE) is preferably 70 or less, more preferably 60 or less, still more ^preferably 50 or less. Furthermore, L ^* (SCE) is more preferably 40 or less. Light reflected by an object includes specular reflection light and diffuse reflection light, and specular reflection light is light that is difficult to recognize with the naked eye. L ^* (SCE) is a measurement of reflected light that does not include specularly reflected light, and when L ^* (SCE) is 70 or less, the image display device has excellent design when viewed with the naked eye. On the other hand, L ^* (SCI) is a measurement of reflected light including specularly reflected light, and although it has little relevance to visibility with the naked eye, it is possible to measure a color tone close to the true color tone of an object. Therefore, when L ^* (SCI) is 70 or less, the design is excellent even when the visibility of the image display device is affected by the environment. In this specification, the above L ^* (SCI) may be referred to as "reflection L ^* (SCI)" and the above L ^* (SCE) may be referred to as "reflection L ^* (SCE)". Reflection L ^* (SCI) and reflection L ^* (SCE) can be specifically measured by the method described in Examples. Note that the reflection L ^* (SCI) and the reflection L ^* (SCE) may be measured with a transparent layer such as a release liner provided on the surface of the adhesive layer opposite to the aluminum foil.

The pressure-sensitive adhesive layer of the present invention preferably has a circular diameter of 60 mm or more (particularly more than 60 mm), more preferably is 65 mm or more, more preferably 70 mm or more, particularly preferably 80 mm or more. When the diameter of the circular shape is 60 mm or more, uneven brightness is further suppressed.
<Light diffusion effect confirmation test>
When an LED lamp is installed on the screen, a glass plate is brought into close contact with the LED lamp, and light is irradiated from the LED lamp onto the screen through the glass plate, a circular light with a diameter of 16 mm appears on the screen. is the position of the LED lamp. Then, when the glass plate side of the measurement sample, in which the adhesive layer of the present invention was bonded to a glass plate, was brought into close contact with an LED lamp, light was irradiated from the LED lamp onto the screen through the glass plate and the adhesive layer. Measure the diameter of the circular light that appears. Note that the measurement may be performed with a transparent layer such as a release liner provided on the surface of the adhesive layer opposite to the glass plate.

The adhesive layer of the present invention may be in any form, for example, an emulsion type, a solvent type (solution type), an active energy ray-curable type, a heat melt type (hot melt type), etc. Examples of the active energy rays include ionizing radiation such as α rays, β rays, γ rays, neutron beams, and electron beams, and ultraviolet rays, with ultraviolet rays being particularly preferred. That is, the active energy ray-curable adhesive layer is preferably an ultraviolet ray-curable adhesive layer.

The adhesive layer of the present invention can be formed by, for example, applying (coating) an adhesive composition for forming the adhesive layer onto a release liner and drying and curing the resulting adhesive composition layer, or It can be manufactured by applying (coating) an adhesive composition onto a release liner and curing the resulting adhesive composition layer by irradiating it with active energy rays. Moreover, if necessary, it may be further dried by heating.

The adhesive composition forming the adhesive layer of the present invention contains, for example, the above-mentioned colorant, the above-mentioned light-diffusing fine particles, and other components as necessary. When the adhesive layer of the present invention is the resin layer, the adhesive composition may contain a resin forming the resin layer, a monomer component that is a constituent component of the resin, an oligomer of the monomer component, a partial polymer, etc. It may also contain a binder component. Examples of adhesive compositions containing resin include so-called solvent-type adhesive compositions. Also. Examples of the pressure-sensitive adhesive composition containing a monomer component, an oligomer component, or a partially polymerized product include a so-called active energy ray-curable pressure-sensitive adhesive composition.

The adhesive layer of the present invention is preferably used for a sheet for sealing one or more optical semiconductor elements arranged on a substrate. When an optical semiconductor element is sealed with a sheet containing the adhesive layer of the present invention, the substrate surface has excellent antireflection properties, and brightness unevenness due to light emitted by the optical semiconductor element is less likely to occur. And color shift is less likely to occur.

[Laminated sheet]
The adhesive layer of the present invention can be laminated with other layers to form a laminated sheet. Examples of the other layers include an adhesive layer other than the adhesive layer of the present invention, a resin layer, a base portion described below, a layer having anti-glare properties, a layer having anti-reflection properties, and the like. Moreover, the said laminated sheet may be equipped with multiple adhesive layers of this invention directly or indirectly. In this case, the plurality of adhesive layers of the present invention may have the same thickness, composition, physical properties, etc., or may have different layers.

The laminated sheet is preferably a sheet for sealing one or more optical semiconductor elements arranged on a substrate (sometimes referred to as a "sheet for optical semiconductor element sealing"). The optical semiconductor element sealing sheet includes at least a sealing resin layer. In this specification, "sealing the optical semiconductor element" refers to embedding at least a portion of the optical semiconductor element in a sealing resin layer, or following and covering with the above-mentioned sealing resin layer. Say something. The sealing resin layer has flexibility that allows it to embed at least a portion of the optical semiconductor element or to follow and cover it with the sealing resin layer.

When the adhesive layer of the present invention is used as a component of a sheet for encapsulating optical semiconductor devices, it has both the ability to diffuse light and the ability to prevent light from being reflected by metal wiring provided on a substrate. functions as a layer with Therefore, by using the adhesive layer of the present invention, it is possible to combine a light-diffusing functional layer, which is intended to exhibit a light-diffusing function, as a component of an optical semiconductor element sealing sheet, and a light-diffusing functional layer provided on a substrate. Compared to the case where two layers are used, including a colored layer whose purpose is to prevent the reflection of light from metal wiring, etc., the thickness of one layer is sufficient, so it can be made thinner, and the optical semiconductor device can be made thinner. Contributes to downsizing.

When the laminated sheet is the optical semiconductor element sealing sheet, the adhesive layer of the present invention is preferably a layer constituting the sealing resin layer. The sealing resin layer may include, as the other layer, a non-diffusion functional layer that is not intended to exhibit a light diffusing function.

The non-diffusion functional layer is a non-colored layer different from the colored layer described below. The non-diffusion functional layer may be a colorless layer or may be slightly colored. The non-diffusion functional layer may be transparent or non-transparent.

The haze value (initial haze value) of the non-diffusing functional layer is not particularly limited, but from the viewpoint of increasing the light transmittance of the laminated sheet, it is preferably less than 30%, more preferably 10% or less, and even more preferably 5%. The content is particularly preferably 1% or less, and may be 0.5% or less. Note that the lower limit of the haze value of the non-diffusion functional layer is not particularly limited.

The total light transmittance of the non-diffusing functional layer is not particularly limited, but from the viewpoint of increasing the light transmittance of the laminated sheet, it is preferably 60% or more, more preferably 70% or more, still more preferably 80% or more, especially Preferably it is 90% or more. Further, the upper limit of the total light transmittance of the non-diffusing functional layer is not particularly limited, but may be less than 100%, 99.9% or less, or 99% or less.

The haze value and total light transmittance of the above-mentioned non-diffusing functional layer are the values of a single layer, and can be measured by the method specified in JIS K7136 and JIS K7361-1, and may vary depending on the type and thickness of the non-diffusing functional layer. It can be controlled by etc.

The non-diffusion functional layer is preferably the resin layer. In this case, the resin in the non-diffusion functional layer may be the same as or different from the resin that can be contained in the adhesive layer of the present invention in constituent monomers and their composition ratios.

From the viewpoint of increasing the light transmittance of the laminated sheet, the content of the colorant and/or light-diffusing fine particles in the non-diffusing functional layer is set to 0.000 parts by mass based on 100 parts by mass of the resin constituting the non-diffusing functional layer. It is preferably less than 0.01 part by mass, more preferably less than 0.005 part by mass.

When the sealing resin layer includes the adhesive layer of the present invention and the non-diffusion functional layer, the non-diffusion functional layer may be located on the opposite side of the adherend from the adhesive layer of the present invention. Preferably, it is more preferably located on the surface of the sealing resin layer. When the non-diffusion functional layer is provided at the above position, even if the surface of the adhesive layer of the present invention has an uneven shape in the state where the sheet for encapsulating an optical semiconductor element is bonded together, the surface of the adhesive layer of the present invention The surface of the sealing resin layer on the opposite side from the optical semiconductor element is prevented from being exposed on the surface of the sealing resin layer on the opposite side of the optical semiconductor element, and the surface of the sealing resin layer on the front side tends to be flat, making it difficult to cause diffuse reflection of external light. The appearance of the optical semiconductor device is improved both when emitting light.

The sealing resin layer may include a layer other than the adhesive layer of the present invention and the non-diffusion functional layer. Examples of the other layers include a colored layer, a diffusion function layer, and the like. The colored layer and the diffusion functional layer are layers that do not correspond to the adhesive layer of the present invention. The above-mentioned colored layer is a layer whose purpose is to prevent light from being reflected by metal wiring provided on the substrate, and whose purpose is not to exhibit a light-diffusing function. Further, the above-mentioned diffusion functional layer is a non-colored layer whose purpose is to exhibit the function of diffusing light, and whose purpose is not to prevent reflection of light by metal wiring or the like provided on the substrate. The diffusion functional layer may be a colorless layer or may be slightly colored. The above-mentioned diffusion functional layer may be transparent or non-transparent.

The total number of layers constituting the sealing resin layer is not particularly limited, and may be two or more, or three or more. The total number of the layers is, for example, 10 or less, and may be 5 or less, or 4 or less, from the viewpoint of reducing the thickness of the optical semiconductor device.

The colored layer contains at least the coloring agent. The colored layer is preferably the resin layer. The content of the colorant in the colored layer is preferably 0.2% by mass or more, more preferably 0.4% by mass or more, based on 100% by mass of the total amount of the colored layer. Further, the content of the colorant is, for example, 10% by mass or less, preferably 5% by mass or less, and more preferably 3% by mass or less.

The haze value (initial haze value) of the colored layer is preferably 50% or less, more preferably 40% or less, still more preferably 30% or less, particularly preferably 20% or less. Further, the haze value of the colored layer is preferably 1% or more, more preferably 3% or more, still more preferably 5% or more, particularly preferably 8% or more, and may be 10% or more.

The total light transmittance of the colored layer is preferably 40% or less, more preferably 30% or less, even more preferably 25% or less, particularly preferably 20% or less. Further, the total light transmittance of the colored layer is preferably 0.5% or more, more preferably 1% or more, even more preferably 1.5% or more, particularly preferably 2% or more, and 2. It may be 5% or more, or 3% or more.

The haze value and total light transmittance of the above-mentioned colored layer are the values of a single layer, and can be measured by the method specified in JIS K7136 and JIS K7361-1. It can be controlled by the amount etc.

It is preferable that the above-mentioned diffusion functional layer contains the above-mentioned light-diffusing fine particles. The diffusion functional layer is preferably the resin layer. The above-mentioned diffusion functional layer may be transparent or non-transparent. The content of the colorant in the diffusion functional layer is preferably less than 0.2% by mass, more preferably less than 0.1% by mass, and even more preferably 0.05% by mass, based on the total amount of the diffusion functional layer 100% by mass. %, and may be less than 0.01% by weight or less than 0.005% by weight.

The content of the light-diffusing fine particles in the diffusion functional layer is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and Preferably it is 0.1 part by mass or more, particularly preferably 0.15 part by mass or more. Further, the content of the light-diffusing fine particles is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, based on 100 parts by mass of the resin constituting the diffusion functional layer.

The haze value (initial haze value) of the diffusion functional layer is preferably 30% or more, more preferably 40% or more, even more preferably 50% or more, particularly preferably 60% or more, 70% or more, 80% or more. , 90% or more, 95% or more, or 97% or more, and preferably around 99.9%. Note that the upper limit of the haze value of the diffusion functional layer may be 100%.

The total light transmittance of the diffusion functional layer is preferably 40% or more, more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more. Further, the total light transmittance of the diffusion functional layer may be less than 100%, 99.9% or less, or 99% or less.

The haze value and total light transmittance of the above-mentioned diffusion functional layer are the values of a single layer, and can be measured by the method specified in JIS K7136 and JIS K7361-1. It can be controlled by the type and amount of diffusible particles.

Each layer constituting the laminate sheet may or may not have adhesiveness and/or adhesiveness independently. It is particularly preferable that each layer constituting the sealing resin layer has adhesiveness and/or adhesiveness. By having such a structure, the above-mentioned sealing resin layer can easily seal the optical semiconductor element, and has excellent adhesion and/or adhesion between each layer, making it possible to seal the optical semiconductor element. Superior in nature. In particular, it is preferable that at least the layer that contacts the optical semiconductor element has adhesiveness and/or adhesiveness. By having such a configuration, the followability and embedding of the optical semiconductor element by the sealing resin layer are excellent. As a result, the design is excellent even when the height difference due to the optical semiconductor element is high. Note that layers other than the layer that contacts the optical semiconductor element do not need to have adhesiveness and/or adhesiveness. In this case, adhesion between adjacent encapsulating resin layers in the tiling state is low, resulting in small-sized adjacent laminates (laminates in which optical semiconductor elements placed on a substrate are encapsulated by encapsulating resin layers). ) When separating the sheets, damage to the sheet and adhesion of the adjacent sealing resin layer are less likely to occur.

Each layer constituting the sealing resin layer may be independently a radiation-curable resin layer or a radiation-non-curable resin layer.

The sealing resin layer may have a single layer structure consisting of a single layer of the adhesive layer of the present invention, or a laminated structure including the adhesive layer of the present invention. The laminated structure of the sealing resin layer is a structure consisting of two adhesive layers of the present invention; one layer is the adhesive layer of the present invention, and the other layer is the adhesive layer of the present invention; Structure that is an adhesive layer, a colored layer, a diffusion functional layer, or a non-diffusion functional layer of the invention (in no particular order); Consisting of three layers, one layer is the adhesive layer of the invention, and the other two layers are each of the adhesive layers of the invention. Structure that is an adhesive layer, a colored layer, a diffusion functional layer, or a non-diffusion functional layer of the invention (in no particular order); Consisting of 4 layers, one layer is the adhesive layer of the invention, and the other three layers are each of the adhesive layer of the invention. Examples include a structure (in no particular order) that is an adhesive layer, a colored layer, a diffusion functional layer, or a non-diffusion functional layer of the invention. More specifically, for example, [adhesive layer of the present invention], [adhesive layer of the present invention/non-diffusive functional layer], [adhesive layer of the present invention/diffusion functional layer], [adhesive of the present invention] layer/non-diffusion functional layer/diffusion functional layer] (in order from the optical semiconductor element side).

<Base material part>
The laminated sheet may include a base material portion. Moreover, in the sheet for encapsulating an optical semiconductor element, the encapsulating resin layer may be provided on at least one surface of the base material portion. When the base material part is provided on the opposite side of the encapsulating resin layer from the optical semiconductor element side in the encapsulating sheet for optical semiconductor elements, the surface of the encapsulating resin layer can be made flat, which makes it easier to The appearance of the optical semiconductor device is improved both when the light is off and when the light is emitted. Further, by forming an anti-glare layer or an anti-reflection layer, which will be described later, on the base material portion, anti-glare properties and anti-reflection properties can be imparted to the optical semiconductor device. Further, the laminated sheet serves as a support for the pressure-sensitive adhesive layer of the present invention, and by providing the base material portion, the laminated sheet has excellent handling properties. Note that the base material portion does not necessarily have to be provided.

The base material portion may be a single layer, or may be a multilayer having the same or different compositions, thicknesses, etc. When the base material part is multi-layered, each layer may be bonded together by another layer such as an adhesive layer. The base material layer used for the base material part is a part that is attached to an adherend together with the adhesive layer and sealing resin layer of the present invention, and is peeled off when the laminated sheet is used (applied). A "base material" does not include a release liner or a surface protection film that merely protects the surface of the base material.

Examples of the base layer constituting the base portion include glass and plastic base materials (especially plastic films). Examples of the resin constituting the plastic base material include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymerized polypropylene, block copolymerized polypropylene, and homopolyprolene. , polybutene, polymethylpentene, ionomer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester (random, alternating) copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene- Polyolefin resins such as propylene copolymers, cyclic olefin polymers, ethylene-butene copolymers, and ethylene-hexene copolymers; polyurethanes; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, and polybutylene terephthalate (PBT); Polycarbonate; Polyimide resin; Polyetheretherketone; Polyetherimide; Polyamide such as aramid and wholly aromatic polyamide; Polyphenylsulfide; Fluororesin; Polyvinyl chloride; Polyvinylidene chloride; Cellulose resin such as triacetylcellulose (TAC) ; silicone resin; acrylic resin such as polymethyl methacrylate (PMMA); polysulfone; polyarylate; polyvinyl acetate. The above resins may be used alone or in combination of two or more. The base material layer may be various optical films such as an antireflection (AR) film, a polarizing plate, and a retardation plate.

The thickness of the plastic film is preferably 20 to 300 μm, more preferably 40 to 250 μm. When the thickness is 20 μm or more, the supportability and handleability of the laminated sheet are further improved. When the thickness is 300 μm or less, the overall thickness when bonded to an adherend can be made thinner.

The surface of the base material on the side where the adhesive layer and the sealing resin layer are provided may be subjected to, for example, corona discharge treatment, plasma treatment, sand mat treatment, ozone exposure treatment, etc., for the purpose of improving adhesion, retention, etc. , physical treatment such as flame exposure treatment, high voltage electric shock exposure treatment, ionizing radiation treatment; chemical treatment such as chromic acid treatment; surface treatment such as adhesion treatment using a coating agent (undercoat). The surface treatment for improving adhesion is preferably applied to the entire surface of the base material on the pressure-sensitive adhesive layer side or the sealing resin layer side.

The thickness of the base material portion is preferably 5 μm or more, more preferably 10 μm or more, from the viewpoint of excellent support function and surface scratch resistance. The thickness of the base material portion is preferably 300 μm or less, more preferably 250 μm or less, from the viewpoint of better transparency.

<Laminated sheet>
The laminated sheet may include a layer having anti-glare and/or anti-reflection properties. By having such a configuration, when the optical semiconductor element is sealed, gloss and light reflection can be suppressed and the appearance can be improved. Examples of the layer having anti-glare properties include an anti-glare treated layer. Examples of the layer having antireflection properties include an antireflection treated layer. The anti-glare treatment and the anti-reflection treatment can be carried out using known or commonly used methods. The layer having anti-glare properties and the layer having anti-reflection properties may be the same layer or may be different layers. The layer having anti-glare properties and/or anti-reflection properties may have only one layer, or may have two or more layers. Further, the layer having anti-glare and/or anti-reflection properties is preferably provided on one surface of the laminated sheet.

FIG. 1 and FIG. 2 are cross-sectional views showing one embodiment of a sheet for encapsulating an optical semiconductor element including an adhesive layer of the present invention. As shown in FIGS. 1 and 2, the optical semiconductor element sealing sheet 1 can be used to seal one or more optical semiconductor elements arranged on a substrate, and has a base material part. 4 and a sealing resin layer 2 formed on the base material part 4. The base portion 4 is composed of a base film 41 and a functional layer 42 which is a surface treatment layer, but may be composed of the base film 41 without the functional layer 42.

In the optical semiconductor element sealing sheet 1 shown in FIG. 1, the sealing resin layer 2 is formed of a single layer of the adhesive layer 21 of the present invention. A release liner 3 is attached to one side of the adhesive layer 21 of the present invention, and a base member 4 is attached to the other side.

In the optical semiconductor element sealing sheet 1 shown in FIG. 2, the sealing resin layer 2 is formed from a laminate of the adhesive layer 21 of the present invention and the non-diffusive functional layer 22. The non-diffusion functional layer 22 is directly laminated on the adhesive layer 21 of the present invention. A release liner 3 is attached to the adhesive layer 21 of the present invention, and a base member 4 is attached to the non-diffusion functional layer 22.

In FIGS. 1 and 2, the functional layer 42 is a layer that is not included in the sealing resin layer, and includes a layer that can impart various functions to the optical semiconductor element sealing sheet. Examples of the functional layer include a layer including a surface treatment layer. By having such a configuration, the sheet for encapsulating an optical semiconductor element in which a functional layer including a surface treatment layer is laminated has excellent light diffusivity and light extraction efficiency. Examples of the surface treatment layer include an anti-glare treatment layer (antiglare treatment layer), an antireflection treatment layer, a hard coat treatment layer, and the like. The functional layer may be laminated on the encapsulating resin layer in the optical semiconductor element encapsulating sheet, or may be laminated on the base material when the base material is provided, but It is preferable that it is laminated on the material part, and it is preferable that it is laminated on the opposite side of the base material part to the side that is provided with the sealing resin layer.

The haze value (initial haze value) of the laminated sheet is not particularly limited, but from the viewpoint of achieving better luminance unevenness suppression effect and design, it is preferably 80% or more, more preferably 85% or more, More preferably, it is 90% or more, particularly preferably 95% or more. Note that the upper limit of the haze value is not particularly limited.

The total light transmittance of the laminated sheet is not particularly limited, but from the viewpoint of further improving the antireflection function of metal wiring and the like, the total light transmittance of the laminated sheet is preferably 40% or less, more preferably 30% or less, and even more preferably 20%. It is as follows. Further, the total light transmittance is preferably 0.5% or more from the viewpoint of ensuring brightness.

The haze value and total light transmittance can be measured by the methods defined in JIS K7136 and JIS K7361-1, respectively. It can be controlled by the stacking order, type, thickness, etc.

The thickness of the adhesive layer of the present invention is preferably 5 to 100 μm, more preferably 10 to 80 μm, and still more preferably 20 to 70 μm. When the thickness is 5 μm or more, antireflection properties and light diffusion functions are better. When the thickness is 100 μm or less, it is easier to ensure light transmittance. Moreover, the adhesive layer of the present invention can be made as thin as 100 μm or less while having both the functions of a conventional colored layer and a light-diffusing functional layer.

The thickness of the non-diffusion functional layer is, for example, 5 to 480 μm, preferably 5 to 100 μm, more preferably 10 to 80 μm, and still more preferably 20 to 70 μm. When the thickness is 5 μm or more, the sealing performance of the optical semiconductor element becomes better. When the thickness is 480 μm or less, it is easier to ensure brightness when the optical semiconductor element emits light.

The thickness of the sealing resin layer is, for example, 100 to 500 μm, preferably 120 to 400 μm, and more preferably 150 to 300 μm. When the thickness is 100 μm or more, the sealing properties of the optical semiconductor device will be better. When the thickness is 500 μm or less, the thickness of the optical semiconductor device becomes thinner.

The thickness of the laminated sheet (for example, the optical semiconductor element sealing sheet) is not particularly limited, but is preferably 500 μm or less, more preferably 400 μm or less, still more preferably 300 μm or less. Since the adhesive layer of the present invention has both the functions of a conventional colored layer and a light-diffusing functional layer, it can be made thinner than a conventional laminated sheet having both a colored layer and a light-diffusing functional layer. Further, the thickness is, for example, 10 μm or more.

[Release liner]
The adhesive layer of the present invention and the sealing resin layer may be formed on the release-treated surface of the release liner. When the adhesive layer of the present invention or the sealing resin layer is formed on the base material part, the release liner is opposite to the base material layer of the adhesive layer of the present invention or the sealing resin layer. The side will be the side that will be in contact with the release liner. When the base material portion is not provided, both surfaces of the adhesive layer of the present invention or the sealing resin layer may be the side that comes into contact with the release liner. The release liner is used as a protective material for the adhesive layer of the present invention or the above-mentioned laminated sheet, and is peeled off when bonding to an adherend. Note that the release liner does not necessarily have to be provided.

Examples of the above-mentioned release liner include polyethylene terephthalate (PET) film, polyethylene film, polypropylene film, plastic films and papers whose surface is coated with a release agent such as a fluorine-based release agent or a long-chain alkyl acrylate release agent. It will be done.

The thickness of the release liner is, for example, 10 to 200 μm, preferably 15 to 150 μm, and more preferably 20 to 100 μm. When the thickness is 10 μm or more, the release liner is less likely to break due to cuts during processing. When the thickness is 200 μm or less, the release liner can be more easily peeled off from the laminated sheet during use.

[Method for manufacturing a sheet for encapsulating optical semiconductor elements]
An embodiment of the method for manufacturing the above sheet for encapsulating an optical semiconductor element will be described. For example, the sheet 1 for encapsulating an optical semiconductor element shown in FIG. 1 has an adhesive layer 21 of the present invention sandwiched between the release-treated surfaces of two release liners. One of the release liners bonded to the adhesive layer 21 of the present invention is release liner 3. Next, one of the release liners (the release liner that is not the release liner 3) attached to the adhesive layer 21 of the present invention is peeled off to expose the surface of the adhesive layer 21 of the present invention, and the exposed surface is attached to the base material 4. Paste it on. In this way, the sheet 1 for encapsulating an optical semiconductor element shown in FIG. 1 can be produced, in which the adhesive layer 21 of the present invention and the release liner 3 are laminated in this order on the base material part 4.

In addition, the sheet 1 for encapsulating optical semiconductor elements shown in FIG. 2 is made by separately producing the adhesive layer 21 and the non-diffusion functional layer 22 of the present invention, which are sandwiched between the release-treated surfaces of two release liners, respectively. do. One of the release liners bonded to the adhesive layer 21 of the present invention is release liner 3. Next, one side of the release liner attached to the non-diffusion functional layer 22 is peeled off to expose the surface of the non-diffusion functional layer 22, and the exposed surface is bonded to the base member 4. Thereafter, one of the release liners (the release liner that is not the release liner 3) attached to the adhesive layer 21 of the present invention is peeled off, and the release liner on the surface of the non-diffusion functional layer 22 is peeled off to expose the non-diffusion functional layer 22. The exposed surface of the adhesive layer 21 of the present invention is bonded to the surface. Note that the various layers can be laminated using a known roller or laminator. In this way, the sheet 1 for encapsulating optical semiconductor elements shown in FIG. 2 was produced, in which the non-diffusion functional layer 22, the adhesive layer 21 of the present invention, and the release liner 3 were laminated in this order on the base material part 4. can do.

[Optical semiconductor device]
Optical semiconductor devices such as displays can be manufactured using the above sheet for encapsulating optical semiconductor elements. An optical semiconductor device manufactured using the optical semiconductor element sealing sheet includes a substrate, an optical semiconductor element disposed on the substrate, and the optical semiconductor element sealing sheet that seals the optical semiconductor element. Or a cured product obtained by curing the sheet. The cured product is a cured product in which the radiation-curable resin layer is cured by radiation irradiation when the optical semiconductor element sealing sheet includes a radiation-curable resin layer.

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

In the above-mentioned optical semiconductor device, the above-mentioned optical semiconductor element sealing sheet has excellent followability to irregularities when the optical semiconductor element is used as a convex part and the gaps between a plurality of optical semiconductor elements are used as concave parts, and the optical semiconductor element has excellent followability. In addition, since the embeddability is excellent, it is preferable to seal a plurality of optical semiconductor elements at once.

The height of the optical semiconductor element on the substrate (height from the substrate surface to the front end of the optical semiconductor element) is preferably 500 μm or less. When the height is 500 μm or less, the sealing resin layer has better followability with respect to the uneven shape.

FIG. 3 shows an embodiment of an optical semiconductor device using the optical semiconductor element sealing sheet 1 shown in FIG. 1. The optical semiconductor device 10 shown in FIG. The base material part 4 is laminated on the layer 7. The plurality of optical semiconductor elements 6 are collectively sealed in a sealing resin layer 7. The sealing resin layer 7 is formed of a single layer of a coloring layer 71 with a diffusion function. The diffusion functional colored layer 71 follows the uneven shape formed by the plurality of optical semiconductor elements 6, adheres closely to the optical semiconductor element 6 and the substrate 5, and embeds the optical semiconductor element 6. Furthermore, the diffusion functional colored layer 71 has an uneven shape at its interface on the optical semiconductor element 6 side, following the above-mentioned uneven shape, and the other interface is flat.

FIG. 4 shows an embodiment of an optical semiconductor device using the optical semiconductor element sealing sheet 1 shown in FIG. 2. The optical semiconductor device 10 shown in FIG. 4 includes a substrate 5, a plurality of optical semiconductor elements 6 arranged on one surface of the substrate 5, a sealing resin layer 7 for sealing the optical semiconductor elements 6, and a sealing resin layer 7. The base material part 4 is laminated on the layer 7. The plurality of optical semiconductor elements 6 are collectively sealed in a sealing resin layer 7. The sealing resin layer 7 is formed by laminating a diffusion functional colored layer 71 and a non-diffusion functional layer 73. The diffusion functional colored layer 71 follows the uneven shape formed by the plurality of optical semiconductor elements 6, adheres closely to the optical semiconductor element 6 and the substrate 5, and embeds the optical semiconductor element 6. Furthermore, the diffusion functional colored layer 71 has an uneven shape at its interface on the optical semiconductor element 6 side, following the above-mentioned uneven shape, and the other interface is flat.

The sealing resin layer 7 is formed by the sealing resin layer 2. Specifically, when the sealing resin layer 2 in the optical semiconductor element sealing sheet 1 does not have a radiation-curable resin layer, the sealing resin layer 2 becomes the sealing resin layer 7 in the optical semiconductor device 10. . On the other hand, when the sealing resin layer 2 in the optical semiconductor element sealing sheet 1 has a radiation-curable resin layer, for example, when the adhesive layer 21 of the present invention is a radiation-curable resin layer, the adhesive of the present invention By curing the layer 21, a diffusion functional coloring 71 is formed and the sealing resin layer 7 is formed.

In the optical semiconductor device 10 shown in FIG. 4, the optical semiconductor element 6 is completely embedded and sealed in the diffusion functional colored layer 71, and is indirectly sealed by the non-diffusion functional layer 72. ing. That is, the optical semiconductor element 6 is sealed with the sealing resin layer 7 made of a laminate of a colored layer 71 with a diffusion function and a layer 72 with a non-diffusion function. The above optical semiconductor device is not limited to such an embodiment, and for example, as shown in FIG. It may be an aspect in which the

The above-mentioned optical semiconductor device may be one in which individual optical semiconductor devices are tiled. That is, the optical semiconductor device may be one in which a plurality of optical semiconductor devices are arranged in a tile shape in a planar direction.

Preferably, the optical semiconductor device includes a self-luminous display device. Further, by combining the above self-luminous display device and a display panel as necessary, a display body that is an image display device can be obtained. The optical semiconductor element in this case is an LED element. Examples of the self-luminous display device include an LED display, a backlight, an organic electroluminescence (organic EL) display device, and the like. It is particularly preferable that the backlight is a full-surface direct type backlight. The backlight includes, for example, a laminate including the substrate and a plurality of optical semiconductor elements arranged on the substrate as at least a part of its constituent members. For example, in the self-luminous display device, a metal wiring layer for sending a light emission control signal to each LED element is laminated on the substrate. LED elements that emit light of red (R), green (G), and blue (B) colors are alternately arranged on a substrate with metal wiring layers interposed therebetween. The metal wiring layer is made of metal such as copper, and displays each color by adjusting the degree of light emission of each LED element.

The above-mentioned optical semiconductor element sealing sheet is used for optical semiconductor devices that are used by being folded, such as optical semiconductor devices having a foldable image display device (flexible display) (in particular, a foldable image display device (foldable display)). It can be used for equipment. Specifically, it can be used for foldable backlights, foldable self-luminous display devices, and the like.

The optical semiconductor device sealing sheet has excellent followability and embeddability for optical semiconductor devices, and is therefore preferably used both when the optical semiconductor device is a mini LED display device and a micro LED display device. be able to.

[Method for manufacturing optical semiconductor device]
The above-mentioned optical semiconductor device can be manufactured by, for example, bonding the above-mentioned optical semiconductor element sealing sheet to a substrate on which an optical semiconductor element is arranged, and sealing the optical semiconductor element with a sealing resin layer. .

(Sealing process)
In the method for manufacturing an optical semiconductor device using the above sheet for encapsulating an optical semiconductor element, the above sheet for encapsulating an optical semiconductor element is bonded to a substrate on which an optical semiconductor element is arranged, and a resin layer for sealing is used to form an optical semiconductor device. It has a sealing process of sealing the element. Specifically, in the sealing step, first, the release liner is peeled off from the optical semiconductor element sealing sheet to expose the sealing resin layer. Then, in a laminate (such as an optical member) comprising a substrate and an optical semiconductor element (preferably a plurality of optical semiconductor elements) arranged on the substrate, the optical semiconductor is placed on the substrate surface on which the optical semiconductor element is arranged. The exposed surfaces of the encapsulation resin layers of the element encapsulation sheets are bonded together, and when the laminate includes a plurality of optical semiconductor elements, the encapsulation resin layer further fills the gaps between the plurality of optical semiconductor elements. The plurality of optical semiconductor elements are sealed together. Specifically, the adhesive layer 21 of the present invention exposed by peeling off the release liner 3 from the optical semiconductor element sealing sheet 1 shown in FIG. 1 or FIG. The optical semiconductor element sealing sheet 1 is bonded to the surface of the substrate 5 on which the optical semiconductor element 6 is arranged, and the optical semiconductor element 6 is embedded in the sealing resin layer 2.

The temperature during the above bonding is, for example, within the range of room temperature to 110°C. Further, during the above bonding, pressure may be reduced or increased. It is possible to suppress the formation of voids between the sealing resin layer and the substrate or the optical semiconductor element due to reduced pressure or increased pressure. Moreover, in the said sealing process, it is preferable to bond the optical semiconductor element sealing sheet together under reduced pressure, and to apply pressure after that. The pressure for reducing the pressure is, for example, 1 to 100 Pa, and the time for reducing the pressure is, for example, 5 to 600 seconds. Further, the pressure when pressurizing is, for example, 0.05 to 0.5 MPa, and the pressurizing time is, for example, 5 to 600 seconds.

(Radiation irradiation process)
When the sealing resin layer includes a radiation-curable resin layer, the manufacturing method further includes the substrate, an optical semiconductor element disposed on the substrate, and the optical semiconductor element for sealing the optical semiconductor element. The method may include a radiation irradiation step of irradiating a laminate including an element sealing sheet with radiation to cure the radiation-curable resin layer to form a cured material layer. As mentioned above, examples of the radiation include electron beams, ultraviolet rays, α rays, β rays, γ rays, and X rays. Among these, ultraviolet light is preferred. The temperature during radiation irradiation is, for example, within the range of room temperature to 100° C., and the irradiation time is, for example, 1 minute to 1 hour.

(dicing process)
The manufacturing method further includes a dicing step of dicing a laminate including the substrate, an optical semiconductor element disposed on the substrate, and the optical semiconductor element sealing sheet for sealing the optical semiconductor element. may be provided. The above-mentioned laminate may be formed on a laminate that has undergone the above-mentioned radiation irradiation step. When the laminate includes a cured material layer in which the radiation-curable resin layer is cured by the radiation irradiation, in the dicing step, the cured material layer of the optical semiconductor element sealing sheet and the side edges of the substrate are diced. Remove. Thereby, the surface of the cured material layer, which has been sufficiently cured and whose tackiness has been reduced, can be exposed on the side surface. The above-mentioned dicing can be performed by a known or commonly used method, for example, by using a dicing blade or by laser irradiation.

(Tiling process)
The manufacturing method may further include a tiling step of arranging the plurality of optical semiconductor devices obtained in the dicing step so as to be in contact with each other in a planar direction. In the tiling step, the plurality of laminates obtained in the dicing step are arranged and tiled so as to be in contact with each other in a planar direction. In this way, one large display can be produced.

In the manner described above, an optical semiconductor device can be manufactured. When the sealing resin layer 2 in the optical semiconductor element sealing sheet 1 does not have a radiation-curable resin layer, the sealing resin layer 2 becomes the sealing resin layer 7 in the optical semiconductor device 10 . On the other hand, when the sealing resin layer 2 in the optical semiconductor element sealing sheet 1 has a radiation-curable resin layer, for example, when the adhesive layer 21 of the present invention is a radiation-curable resin layer, the adhesive of the present invention By curing the layer 21, a diffusion functional colored layer 71 is formed, which becomes the sealing resin layer 7.

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

Manufacturing example 1
(Preparation of acrylic prepolymer solution A)
In a separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet tube, 67 parts by mass of butyl acrylate (BA), 14 parts by mass of cyclohexyl acrylate (CHA), and 4-hydroxybutyl acrylate were added as monomer components. (4-HBA) 19 parts by mass, 0.09 parts by mass of photopolymerization initiator (trade name "omnirad 184", manufactured by IGM Resins Italia Srl), and photopolymerization initiator (trade name "omnirad 651", manufactured by IGM Resins Italia) After adding 0.09 parts by mass (manufactured by Srl), nitrogen gas was flowed and nitrogen substitution was performed for about 1 hour while stirring. Thereafter, polymerization was carried out by irradiating ultraviolet rays at 5 mW/cm ² , and the reaction rate was adjusted to 5 to 15% to obtain acrylic prepolymer solution A.

Manufacturing example 2
(Preparation of adhesive composition A)
To the acrylic prepolymer solution A prepared in Production Example 1 (the total amount of prepolymer is 100 parts by mass), 9 parts by mass of 2-hydroxyethyl acrylate (HEA), 8 parts by mass of 4-hydroxybutyl acrylate (4HBA), and polypropylene were added. As a functional monomer, 0.02 parts by mass of dipentaerythritol hexaacrylate (trade name "KAYARAD DPHA", manufactured by Shin-Nakamura Chemical Co., Ltd.), a silane coupling agent (trade name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd., Adhesive composition A was prepared by adding 0.35 parts by mass of 3-glycidoxypropyltrimethoxysilane) and 0.3 parts by mass of a photopolymerization initiator (trade name "omnirad 651", manufactured by IGM Resins Italia Srl). I got it.

Examples 1 to 12
Adhesive composition A and additives were mixed at the mass ratio shown in Table 1 or Table 2. This mixture (adhesive composition) is applied on the release-treated surface of a release liner (trade name "MRE38", manufactured by Mitsubishi Chemical Corporation, polyethylene terephthalate film with release treatment on one side, thickness 38 μm). After forming a resin composition layer, a release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the resin composition layer. Next, polymerization was carried out by irradiating ultraviolet rays with the illuminance shown in Table 1 or 2 using a black light until the cumulative amount of light was 2520 mJ/cm ² , and the adhesive layer of Examples 1 to 12 (thickness: 50 μm) was formed. was created. Note that 9256BLACK is a 20% dispersion of black pigment (trade name "9256BLACK", manufactured by Tokushiki Co., Ltd.). Tospearl 145 is a product name "Tospearl 145" (manufactured by Momentive Performance Materials Japan, a silicone resin with a refractive index of 1.42 and an average particle size of 4.5 μm). Ti-PURE R-706 is a titanium dioxide pigment with the trade name "Ti-PURE-PAINT COATINGS-DRY GRADES R-706" (manufactured by DUPONT).

Peel off one of the release liners (trade name "MRE38") from the adhesive layer obtained above, and use the exposed adhesive surface as a non-diffusing functional adhesive layer that is not intended to exhibit a light diffusing function. (Thickness: 150 μm, total light transmittance: 92.1%, haze value: 0.4%) The pressure-sensitive adhesive sheets of Examples 1 to 12 were prepared by bonding the adhesive sheets to a pressure-sensitive adhesive surface.

Examples 13-15
Adhesive composition A and additives were mixed at the mass ratio shown in Table 2. This mixture (adhesive composition) is applied on the release-treated surface of a release liner (trade name "MRE38", manufactured by Mitsubishi Chemical Corporation, polyethylene terephthalate film with release treatment on one side, thickness 38 μm). After forming a resin composition layer, a release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the resin composition layer. Next, polymerization was carried out by irradiating ultraviolet rays with the illumination intensity shown in Table 2 using a black light until the cumulative amount of light reached 2520 mJ/cm ² . ) was created. Note that BA is butyl acrylate. Moreover, DPHA is dipentaerythritol hexaacrylate (trade name "KAYARAD DPHA", manufactured by Shin-Nakamura Chemical Co., Ltd.). Furthermore, 4HBA is 4-hydroxybutyl acrylate.

Comparative examples 1 to 4
Adhesive composition A and additives were mixed at the mass ratio shown in Table 2. This mixture (adhesive composition) is applied on the release-treated surface of a release liner (trade name "MRE38", manufactured by Mitsubishi Chemical Corporation, polyethylene terephthalate film with release treatment on one side, thickness 38 μm). After forming a resin composition layer, a release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the resin composition layer. Next, polymerization was performed by irradiating ultraviolet rays with the illuminance shown in Table 2 using a black light until the cumulative light amount was 2520 mJ/cm ² , thereby producing adhesive layers (thickness 50 μm) of Comparative Examples 1 to 4. .

<Evaluation>
The adhesive layers obtained in Examples and Comparative Examples were evaluated as follows. The results are shown in Tables 3 and 4.

(1) Total light transmittance One side of the release liner was peeled off from each adhesive layer produced in Examples and Comparative Examples (two release liners sandwiched together), and the exposed surface of each adhesive layer was covered with a glass plate. (Slide glass, product number "S-9112", manufactured by Matsunami Glass Industries Co., Ltd.). Then, the other release liner was peeled off to prepare a measurement sample having a layer structure of [glass plate/adhesive layer]. The total light transmittance of the above measurement sample was measured using a haze meter (device name: "HM-150", manufactured by Murakami Color Research Institute Co., Ltd.). Measurement was performed by entering measurement light from the adhesive layer side.

(2) Haze value Regarding the measurement sample prepared to measure the above total light transmittance, total light transmittance and diffuse transmittance were measured using a haze meter (equipment name "HM-150", manufactured by Murakami Color Research Institute Co., Ltd.). was measured. Then, the haze value of the measurement sample was determined using the formula "diffuse transmittance/total light transmittance x 100" and was determined as the initial haze value. Measurement was performed by entering measurement light from the adhesive layer side.

(3) Reflection L ^* Measurement One side of the adhesive layer obtained in Examples and Comparative Examples was peeled off on the inner surface of an aluminum foil manufactured by Mitsubishi Aluminum Co., Ltd. (width 30 cm x length 50 m x thickness 12 μm). A measurement sample was prepared by pasting together the surfaces from which the liner had been removed using a hand roller without causing any air bubbles to be trapped. After bonding, the panels were left at 25° C. for 30 minutes in the dark. Thereafter, the bonded product was cut out in a size larger than 5.0 cm x 5.0 cm. Thereafter, the measurement sample was placed on a flat surface with the release liner surface of the adhesive layer facing up. Then, L ^* (SCI) and L ^* (SCE) were measured from the release liner surface side using a spectrophotometer (trade name "CM-26dG", manufactured by Konica Minolta, Inc.). The measurement area of the colorimeter was placed in the center of the sample to be measured, and measurements were made under the following conditions. Furthermore, before performing measurements with the spectrophotometer, zero point calibration, white calibration, and GROSS calibration were performed according to the manufacturer's manual. In addition, when measuring only the aluminum foil (inner winding surface), L ^* (SCI) was 95.88 and L ^* (SCE) was 88.32. When both reflection L ^* (SCI) and reflection L ^* (SCE) are 60 or less, the antireflection property is ``○'', and when one is over 60 and 70 or less and the other is 70 or less (〇 and × The antireflection property was evaluated as "x" when at least one of the antireflection properties exceeded 70.
<Measurement conditions>
Measurement method: Color & Gloss Geometry: DI: 8°, DE: 8°
Specular reflection light processing: SCI+SCE
Observation light source: D65
Observation conditions: 10° field of view Measurement diameter: MAV (8 mm)
UV conditions: 100%Full
Automatic average measurement: 3 times Zero calibration skip: Enabled

(4) Light diffusion effect confirmation test Peel off one release liner of each adhesive layer prepared in Examples and Comparative Examples, and use a hand roller to roll a glass plate (slide glass, product number "S- 9112'', manufactured by Matsunami Glass Industries Co., Ltd., 76 mm x 52 mm x 1.0 to 1.2 mm). After bonding, the panels were left at 25° C. for 30 minutes in the dark. The size of the attached adhesive layer was appropriately cut to the same size as the glass plate, and a measurement sample was prepared. An LED lamp (product name ``LK-3PG'', manufactured by EK Japan Co., Ltd.) was installed at the top of the screen so that the height was 2.4 cm. The glass plate side of the obtained measurement sample was brought into close contact with the LED lamp. A battery box (trade name "AP-180", manufactured by EK Japan Co., Ltd.) was connected to the LED lamp, the LED lamp was turned on, and the diameter of the circular image projected on the screen was measured. When measured using only the glass plate without the adhesive layer, the diameter of the light reflected on the screen was 16 mm. When measured through the adhesive layer, if the light diameter is 65 mm or more, the light diffusion effect is judged to be good (brightness unevenness "○"), and if the light diameter is more than 60 mm and less than 65 mm, the light diffusion effect is judged to be good. It was judged that there was an effect (brightness unevenness: "Δ"), and when the light diameter was 60 mm or less, it was judged that there was no light diffusion effect (brightness unevenness: "x").

(5) Compatibility “○” indicates that both anti-reflection property and brightness unevenness are “○”, and cases where one of anti-reflection property and brightness unevenness is “△” and the other is “○” or “△” The evaluation was rated as "△", and the case where at least one of antireflection property and brightness unevenness was "x" was evaluated as "x".

Variations of the invention according to the present disclosure will be described below.
[Appendix 1] An adhesive layer having a haze value of 61% or more and a total light transmittance of 69% or less.
[Appendix 2] A laminated sheet comprising the adhesive layer according to Appendix 1.
[Additional Note 3] The laminated sheet according to Additional Note 2, comprising a layer having anti-glare and/or antireflection properties on one surface.
[Appendix 4] The laminated sheet according to Appendix 2, which has a thickness of 500 μm or less.
[Appendix 5] An adhesive composition containing a colorant and light-diffusing fine particles, and having a haze value of 61% or more and a total light transmittance of 69% or less when forming an adhesive layer.
[Appendix 6] A substrate, an optical semiconductor element disposed on the substrate, and a laminated sheet or a cured product thereof according to any one of Appendices 2 to 4, which seals the optical semiconductor element. Optical semiconductor device.

1 Sheet for optical semiconductor element sealing 2 Resin layer for sealing 21 Adhesive layer of the present invention 22 Non-diffusion functional layer 3 Release liner 4 Base material part 41 Base film 42 Functional layer 5 Substrate 6 Optical semiconductor element 7 Sealing resin Layer 71 Diffusion function colored layer 72 Non-diffusion function layer 10 Optical semiconductor device

The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples in any way. Note that Example 3 shall be read as Reference Example 1.

Claims (6)

An adhesive layer having a haze value of 61% or more and a total light transmittance of 69% or less. A laminated sheet comprising the adhesive layer according to claim 1. The laminated sheet according to claim 2, comprising a layer having anti-glare and/or anti-reflection properties on one surface. The laminated sheet according to claim 2, having a thickness of 500 μm or less. An adhesive composition containing a colorant and light-diffusing fine particles, having a haze value of 61% or more and a total light transmittance of 69% or less when an adhesive layer is formed. An optical semiconductor device comprising a substrate, an optical semiconductor element disposed on the substrate, and the laminated sheet or cured product thereof according to any one of claims 2 to 4, which seals the optical semiconductor element. .

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