JP2023024316A - Optical semiconductor device sealing sheet - Google Patents

Abstract

A sheet for optical semiconductor element encapsulation suitable for manufacturing a self-luminous display device such as a mini/micro LED display device in which color cast is reduced while improving the antireflection function and contrast of metal wiring. provide.
A sheet (10) for optical semiconductor element encapsulation of the present invention comprises a diffusion layer (1) and an antireflection layer (2). The total light transmittance T ₁ of the diffusion layer 1 and the total light transmittance T 2 of the antireflection layer ₂ satisfy T ₁ >T ₂ , and the haze value H ₁ of the diffusion layer 1 and the haze value of the antireflection layer 2 H ₂ satisfies H ₁ >H ₂ .
[Selection drawing] Fig. 1

Description

TECHNICAL FIELD The present invention relates to a sheet for optical semiconductor element encapsulation. More particularly, the present invention relates to a sheet suitable for encapsulating optical semiconductor elements of self-luminous display 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. A mini/micro LED display device has, as a basic configuration, a substrate in which a large number of micro optical semiconductor elements (LED chips) are arranged at high density is used 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 self-luminous display device such as a mini/micro LED display device, wiring (metal wiring) of metal or metal oxide such as ITO is arranged on the substrate of the display panel. An antireflection layer is sometimes used as a sealing material (see, for example, Patent Document 1). In particular, in an RGB type mini/micro LED display device in which optical semiconductor elements of three colors of RGB are alternately arranged, the antireflection layer can contribute to prevention of color mixture of RGB and improvement of contrast.

JP 2019-204905 A

In the mini/micro LED display device, optical semiconductor elements of three colors of RGB are alternately arranged, but the intensity of the side emission of RGB is different. Specifically, the side emission of R is smaller than that of GB. , there was a problem that a phenomenon called color cast, in which the color tone changes depending on the viewing angle, occurs.

The present invention was conceived under the circumstances as described above. An object of the present invention is to provide a sheet for encapsulating an optical semiconductor element suitable for manufacturing a self-luminous display device such as an LED display device.
Another object of the present invention is to provide an optical semiconductor device, a self-luminous display device, a self-luminous display device, and an optical semiconductor device comprising the sheet for encapsulating an optical semiconductor element, which has an antireflection function of metal wiring and improved contrast while reducing color cast. It is to provide an image display device.

As a result of intensive studies to achieve the above object, the present inventors have found that a diffusion layer and an antireflection layer are provided, and the total light transmittance and haze value of the diffusion layer and the antireflection layer have a specific relationship. Manufacture self-luminous display devices such as mini/micro LED display devices with reduced color cast while improving the antireflection function and contrast of metal wiring, etc., by using a sheet for sealing optical semiconductor elements controlled to found that it can be done. The present invention has been completed based on these findings.

That is, the first aspect of the present invention provides a sheet for encapsulating one or more optical semiconductor elements arranged on a substrate, that is, an optical semiconductor element encapsulating sheet. The optical semiconductor element encapsulating sheet of the first aspect of the present invention comprises a diffusion layer and an antireflection layer.

The configuration in which the sheet for optical semiconductor element encapsulation according to the first aspect of the present invention includes a diffusion layer is suitable for reducing color cast in mini/micro LED display devices. In addition, the configuration in which the optical semiconductor element encapsulating sheet according to the first aspect of the present invention is provided with an antireflection layer is preferable in that it improves the antireflection function and contrast of metal wiring and the like in mini/micro LED display devices. be. The layer for encapsulating the optical semiconductor element may be either a diffusion layer or an antireflection layer. good too.

In the sheet for optical semiconductor element encapsulation of the first aspect of the present invention, the total light transmittance T ₁ of the diffusion layer and the total light transmittance T ₂ of the antireflection layer satisfy T ₁ >T ₂ , That is, the total light transmittance of the diffusion layer is higher than the total light transmittance of the antireflection layer. This configuration is suitable for improving the antireflection function and contrast of metal wiring in the mini/micro LED display device.

In the sheet for optical semiconductor element encapsulation of the first aspect of the present invention, the haze value H ₁ of the diffusion layer and the haze value H ₂ of the antireflection layer satisfy H ₁ >H ₂ , that is, the diffusion The haze value of the layer is higher than the haze value of said antireflection layer. This configuration is preferred for reducing color cast in mini/micro LED displays.

In the optical semiconductor element encapsulating sheet of the first aspect of the present invention, the diffusion layer preferably has a haze value H ₁ of 30 to 99.9%. This configuration is preferred for reducing color cast in mini/micro LED displays.

In the sheet for optical semiconductor element encapsulation of the first aspect of the present invention, the total light transmittance T ₂ of the antireflection layer is preferably 1 to 30%. This configuration is suitable for improving the antireflection function and contrast of metal wiring in the mini/micro LED display device.

In the sheet for optical semiconductor element encapsulation of the first aspect of the present invention, it is preferable that the diffusion layer and the antireflection layer are adjacent to each other. That is, it is preferable that the diffusion layer and the antireflection layer are directly laminated adjacent to each other. This configuration is preferred for reducing color cast in mini/micro LED displays. That is, when the diffusion layer and the antireflection layer are laminated via another layer structure, it is difficult to control the reflection and diffusion of the light emitted from the optical semiconductor element of the mini/micro LED display device. This tends to make it difficult to prevent color cast.

In the sheet for optical semiconductor element encapsulation of the first aspect of the present invention, as one embodiment, it is preferable that the diffusion layer is a resin layer and the antireflection layer is a resin layer. Moreover, it is preferable that the diffusion layer is an adhesive layer, and the antireflection layer is an adhesive layer. In these configurations, the steps of the optical semiconductor elements arranged on the substrate of the mini/micro LED display device are filled with the diffusion layer and/or the antireflection layer without any gaps, so that they are excellent in step absorption and can prevent display unevenness. point is preferable.

A second aspect of the present invention comprises a substrate, one or more optical semiconductor elements arranged on the substrate, and the optical semiconductor element encapsulating sheet of the first aspect of the present invention, wherein the optical semiconductor Provided is an optical semiconductor device in which an element-encapsulating sheet encapsulates the optical semiconductor element. The optical semiconductor device of the second aspect of the present invention is preferably a self-luminous display device. A third aspect of the present invention provides an image display device including the self-luminous display device.

The optical semiconductor device (preferably self-luminous display device) of the second aspect of the present invention and the image display device of the third aspect of the present invention are the optical semiconductor element encapsulating sheet of the first aspect of the present invention. Therefore, the color cast is reduced while improving the antireflection function and contrast of the metal wiring.

By using the sheet for optical semiconductor element encapsulation of the present invention, a self-luminous display device such as a mini/micro LED display device in which color cast is reduced while improving antireflection function and contrast of metal wiring is produced. can do.

FIG. 1 is a schematic diagram (cross-sectional view) showing one embodiment of the sheet for optical semiconductor element encapsulation of the present invention. FIG. 2 is a schematic diagram (cross-sectional view) showing another embodiment of the sheet for optical semiconductor element encapsulation of the present invention. FIG. 3 is a schematic diagram (sectional view) showing an embodiment of the self-luminous display device (mini/micro LED display device) of the present invention. FIG. 4 is a schematic diagram (sectional view) showing another embodiment of the self-luminous display device (mini/micro LED display device) of the present invention.

A first aspect of the present invention provides a sheet for optical semiconductor element encapsulation. The sheet for optical semiconductor element encapsulation of the first aspect of the present invention may be referred to as "the sheet for optical semiconductor element encapsulation of the present invention".

A "sheet for optical semiconductor element encapsulation" is a "sheet for encapsulating one or more optical semiconductor elements arranged on a substrate". The optical semiconductor element is not particularly limited as long as it is a semiconductor element having a light emitting function, and includes a light emitting diode (LED), a semiconductor laser, and the like. In particular, a form used for sealing LED chips of a self-luminous display device such as a mini/micro LED display device in which a plurality of LED chips are arranged on a substrate is preferable.

The sheet for optical semiconductor element encapsulation of the present invention comprises a diffusion layer and an antireflection layer. The diffusion layer and the antireflection layer that constitute the optical-semiconductor element encapsulation sheet of the present invention are sometimes referred to as the "diffusion layer of the present invention" and the "antireflection layer of the present invention", respectively.

The sheet for optical semiconductor element encapsulation of the present invention may be composed only of the diffusion layer and the antireflection layer, or may further have a layer (another layer) other than the diffusion layer and the antireflection layer. Other layers include substrates, release films (separators), surface protection films, adhesive layers, and the like. Other layers can be arranged on the surface of the sheet for optical semiconductor element encapsulation of the present invention or between any layers. You may arrange|position between the layers with.

A second aspect of the present invention comprises a substrate, one or more optical semiconductor elements arranged on the substrate, and the optical semiconductor element encapsulating sheet of the present invention, wherein the optical semiconductor element encapsulating sheet provides an optical semiconductor device in which the optical semiconductor element is encapsulated. The optical semiconductor device of the second aspect of the present invention is preferably a self-luminous display device. A third aspect of the present invention provides an image display device including the self-luminous display device.

The optical semiconductor device of the second aspect of the present invention, the self-luminous display device of the present invention, and the image display device of the third aspect of the present invention are referred to as "the optical semiconductor device of the present invention" and "the self-luminous display of the present invention", respectively. device” and “the image display device of the present invention”.

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto and is merely an example.
1 and 2 are schematic diagrams (cross-sectional views) showing one embodiment of the sheet for optical semiconductor element encapsulation of the present invention. 3 and 4 are schematic diagrams (cross-sectional views) showing one embodiment of the self-luminous display device (mini/micro LED display device) of the present invention.

In FIG. 1, the sheet 10 for encapsulating an optical semiconductor element has a laminated structure in which a diffusion layer 1 and an antireflection layer 2 are laminated. In the optical semiconductor element encapsulating sheet 10, the diffusion layer 1 and the antireflection layer 2 are adjacent to each other, that is, the diffusion layer 1 and the antireflection layer 2 are laminated in direct contact with each other. In FIG. 2, the sheet 11 for encapsulating an optical semiconductor element has a laminated structure in which a diffusion layer 1 and an antireflection layer 2 are laminated with a substrate S interposed therebetween. That is, the diffusion layer 1 and the antireflection layer 2 are laminated via other layers without being in direct contact with each other.

In FIG. 3, a self-luminous display device (mini/micro LED display device) 20 includes a display panel in which a plurality of LED chips 5 are arranged on one side of a substrate 3, and the optical semiconductor element encapsulation sheet 10 of the present invention. . The LED chip 5 on the substrate 3 is sealed with the antireflection layer 2 of the optical semiconductor element sealing sheet 10 . In FIG. 4, a self-luminous display device (mini/micro LED display device) 21 includes a display panel in which a plurality of LED chips 5 are arranged on one side of a substrate 3, and the optical semiconductor element sealing sheet 10 of the present invention. . The LED chip 5 on the substrate 3 is sealed with the diffusion layer 1 of the optical semiconductor element sealing sheet 10 .

In this embodiment, a metal wiring layer 4 for sending light emission control signals to each LED chip 5 is laminated on the substrate 3 of the display panel. LED chips 5 that emit red (R), green (G), and blue (B) lights are alternately arranged on a substrate 3 of the display panel via metal wiring layers 4 . The metal wiring layer 4 is made of a metal such as copper, reflects external light, and reduces the visibility of the image. In addition, the light emitted from each LED chip 5 of each color of RGB is mixed, and the contrast is lowered.

In this embodiment, each LED chip 5 arranged on the display panel is tightly sealed by the diffusion layer 1 and/or the antireflection layer 2 . That is, the laminated structure of the diffusion layer 1 and/or the antireflection layer 2 can serve as a sealing material for each LED chip 5 .

In this embodiment, the diffusion layer 1 and/or the antireflection layer 2 seal each LED chip 5 and metal wiring layer 4 arranged on the display panel. The total light transmittance of the diffusion layer 1 is higher than the total light transmittance of the antireflection layer 2 . That is, since the total light transmittance of the antireflection layer 2 is lower than the total light transmittance of the diffusion layer 1, it has sufficient light shielding properties. Since the optical semiconductor element encapsulating sheet 10 having the antireflection layer 2 with high light shielding properties seals the metal wiring layer 4 , reflection by the metal wiring layer 4 can be prevented.

In this embodiment, the haze value of the diffusion layer 1 is higher than the haze value of the antireflection layer 2, so that the light emitted by the LED chip 5 can be sufficiently diffused, and the color cast that varies in color depending on the viewing angle. can be suppressed.
Each configuration will be described in detail below.

<Sheet for optical semiconductor element encapsulation>
In the optical semiconductor element encapsulating sheet of the present invention, the total light transmittance T ₁ of the diffusion layer of the present invention and the total light transmittance T ₂ of the antireflection layer of the present invention satisfy T ₁ >T ₂ , that is, , the total light transmittance of the diffusion layer of the present invention is higher than the total light transmittance of the antireflection layer of the present invention. This configuration is suitable for improving the antireflection function and contrast of metal wiring in the mini/micro LED display device. From the viewpoint of further improving the antireflection function and contrast of the metal wiring in the mini/micro LED display device, it is preferable to satisfy T ₁ >2T ₂ , more preferably T ₁ >3T ₂ , and still more preferably T ₁ >. 4T ₂ , particularly preferably T ₁ >5T ₂ may be satisfied, T ₁ >6T ₂ , T ₁ >7T ₂ , T ₁ >8T ₂ , T ₁ >9T ₂ , T ₁ >10T ₂ , T ₁ > 11T ₂ , T ₁ >12T ₂ , T ₁ >13T ₂ , T ₁ >14T ₂ , or T ₁ >15T ₂ may be satisfied. Also, from the viewpoint of ensuring the brightness of the mini/micro LED display device, 1000T ₂ >T ₁ or 500T ₂ >T ₁ may be satisfied.

In the sheet for optical semiconductor element encapsulation of the present invention, the difference (T ₁ −T ₂ ) between the total light transmittance T ₁ of the diffusion layer of the present invention and the total light transmittance T ₂ of the antireflection layer of the present invention is From the viewpoint of further improving antireflection function such as metal wiring and contrast in mini/micro LED display devices, it is preferably 30% or more, more preferably 35% or more, still more preferably 40% or more, and particularly preferably 45% or more. and may be 50% or more. Also, from the viewpoint of ensuring the brightness of the mini/micro LED display device, (T ₁ -T ₂ ) may be 95% or less, or 92% or less.

In the optical semiconductor element encapsulating sheet of the present invention, the above relationship between T ₁ and T ₂ depends on the type and thickness of the resin layer and adhesive layer, which will be described later, constituting the diffusion layer and the antireflection layer, and the colorant, which will be described later. , can be controlled by the type and blending amount of the light-diffusing fine particles.

In the optical semiconductor element encapsulating sheet of the present invention, the haze value H ₁ of the diffusion layer of the present invention and the haze value H ₂ of the antireflection layer of the present invention satisfy H ₁ >H ₂ , that is, the diffusion layer is higher than the haze value of the antireflection layer. This configuration is preferred for reducing color cast in mini/micro LED displays. From the viewpoint of more efficiently reducing the color cast of the mini/micro LED display device, it is preferable to satisfy H ₁ >1.1H ₂ , more preferably H ₁ >1.5H ₂ , and even more preferably H ₁ >2H. ₂ , particularly preferably H ₁ >2.5H ₂ , H ₁ >3H ₂ , H ₁ >3.5H ₂ , H ₁ >4H ₂ , H ₁ >4.5H ₂ , H ₁ >5H ₂ , H ₁ >5.5H ₂ , H ₁ >6H ₂ , H ₁ >6.5H ₂ , H ₁ >7H ₂ , H ₁ >7.5H ₂ , H ₁ >8H ₂ , H ₁ >8.5H ₂ , or H ₁ >9H ₂ may be satisfied. Also, from the viewpoint of ensuring the visibility of the mini/micro LED display device, 100H ₂ >H ₁ or 50H ₂ >H ₁ may be satisfied.

In the optical semiconductor element encapsulating sheet of the present invention, the difference (H ₁ −H ₂ ) between the haze value H ₁ of the diffusion layer of the present invention and the haze value H ₂ of the antireflection layer of the present invention is the mini/micro LED From the viewpoint of more efficiently reducing the color cast of the display device, it is preferably 1% or more, more preferably 4% or more, still more preferably 10% or more, particularly preferably 15% or more, and 20% or more. good too. Also, from the viewpoint of ensuring the visibility of the mini/micro LED display device, (H ₁ −H ₂ ) may be 95% or less, or 90% or less.

In the sheet for optical semiconductor element encapsulation of the present invention, the above relationship between H ₁ and H ₂ depends on the type and thickness of the resin layer and the pressure-sensitive adhesive layer, which constitute the diffusion layer and the antireflection layer, and the light diffusion property, which will be described later. It can be controlled by the type and blending amount of the fine particles and the colorant.

The total light transmittance of the optical semiconductor element encapsulating sheet of the present invention (the total light transmittance including the diffusion layer and the antireflection layer) is not particularly limited, but the reflection of metal wiring etc. in the mini / micro LED display device is From the viewpoint of further improving the prevention function and contrast, it is preferably 55% or less, more preferably 50% or less, still more preferably 45% or less, and particularly preferably 40% or less. In addition, the total light transmittance of the optical semiconductor element encapsulating sheet of the present invention is preferably 0.1% or more, more preferably 0.1% or more, from the viewpoint of ensuring the brightness of the mini/micro LED display device. It is 3% or more, more preferably 0.5% or more, particularly preferably 0.7% or more, or may be 0.8% or more.

The total light transmittance of the optical semiconductor element encapsulating sheet of the present invention can be measured by the method defined in JIS 7361, and the type and thickness of the resin layer and adhesive layer described later, the colorant described later, and the light diffusion It can be controlled by the type and blending amount of the organic fine particles.

The haze value (whole haze value including diffusion layer and antireflection layer) of the sheet for optical semiconductor element encapsulation of the present invention is not particularly limited, but it more efficiently reduces color cast of mini/micro LED display devices. From the viewpoint, it is preferably 20% or more, more preferably 30% or more, further preferably 40% or more, particularly preferably 50% or more, 60% or more, 70% or more, 80% or more, 90% or more. more preferably around 99.9% because it is most excellent in color cast improvement effect. In addition, the upper limit of the haze value of the sheet for optical semiconductor element encapsulation is not particularly limited, that is, it may be 100%.

The haze value of the optical semiconductor element encapsulating sheet of the present invention can be measured by the method defined in JIS 7136, and the type and thickness of the resin layer and adhesive layer described later, the light diffusing fine particles described later, and the colorant. can be controlled by the type and blending amount of

The thickness of the optical semiconductor element encapsulating sheet of the present invention (the total thickness including the diffusion layer and the antireflection layer) improves the antireflection function and contrast of metal wiring etc. in the mini / micro LED display device, while improving the color cast. From the viewpoint of reducing the more efficiently, it is preferably 10 to 600 μm, more preferably 20 to 550 μm, even more preferably 30 to 500 μm, 40 to 450 μm, 50 to 400 μm. Especially preferred. In addition, when the sheet for optical semiconductor element encapsulation of the present invention contains a substrate as other layers, the substrate is included in the thickness of the sheet for optical semiconductor element encapsulation of the present invention, but the release film (separator) is not included in the thickness of the sheet for optical semiconductor element encapsulation of the present invention.

The ratio of the thickness of the antireflection layer to the thickness of the diffusion layer (thickness of antireflection layer/thickness of diffusion layer) is not particularly limited. It can be set accordingly to more efficiently reduce the color cast of the mini/micro LED display. Specifically, (thickness of antireflection layer/thickness of diffusion layer) is, for example, about 0.1 to 3, preferably 0.15 to 3, and more preferably 0.2 to 3. good. Also, for example, it may be about 0.1 to 3, preferably 0.1 to 2.5, and more preferably 0.1 to 2.

<Diffusion layer>
The diffusion layer of the present invention is a layer having a function of diffusing light, and is preferably composed of a resin layer. The diffusion layer of the present invention is not limited as long as it has a function of diffusing light, but preferably contains light diffusing fine particles dispersed in the resin layer.

Although the haze value of the diffusion layer of the present invention is not particularly limited, it is preferably 30% or more, more preferably 40% or more, and still more preferably 50% or more from the viewpoint of efficiently reducing color cast of the mini/micro LED display device. % or more, particularly preferably 60% or more, and may be 70% or more, 80% or more, or 90% or more, and more preferably around 99.9% because of its excellent color cast improvement effect. The upper limit of the haze value of the diffusion layer is not particularly limited, that is, it may be 100%.

The total light transmittance of the diffusion layer of the present invention is not particularly limited, but from the viewpoint of ensuring the brightness of the mini/micro LED display device, it is preferably 60% or more, more preferably 70% or more, and still more preferably 80%. 90% or more, particularly preferably 90% or more. Moreover, the upper limit of the total light transmittance of the diffusion layer of the present invention is not particularly limited, but may be less than 100%, or may be 99.9% or less, or 99% or less.

The haze value and total light transmittance of the diffusion layer of the present invention can be measured by the methods defined in JIS 7136 and JIS 7361, respectively. It can be controlled by controlling the type and blending amount of the fine particles and the colorant.

The thickness of the diffusion layer of the present invention is preferably 10 to 300 μm, more preferably 15 to 250 μm, more preferably 20 to 300 μm, from the viewpoint of more efficiently reducing color cast in mini/micro LED display devices. and more preferably 25 to 200 μm.

The light diffusing fine particles have an appropriate difference in refractive index from the resin layer and impart diffusion performance to the diffusion layer. When the diffusion layer contains light-diffusing fine particles, light diffusion performance is imparted, and H ₁ and H ₂ preferably satisfy H ₁ >H ₂ . Examples of light diffusing fine particles include inorganic fine particles and polymer fine particles. Examples of materials for the inorganic fine particles include silica, calcium carbonate, aluminum hydroxide, magnesium hydroxide, clay, talc, and titanium dioxide. Examples of materials for the polymer fine particles include silicone resins, acrylic resins, methacrylic resins (eg, polymethyl methacrylate), polystyrene resins, polyurethane resins, melamine resins, polyethylene resins, and epoxy resins. The light diffusing fine particles are preferably polymer fine particles, and in particular, fine particles composed of silicone resin (e.g., Tospearl series manufactured by Momentive Performance Materials Japan Co., Ltd.) have excellent dispersibility in the resin layer. , It has stability and an appropriate refractive index difference with the resin layer, and a diffusion layer with excellent diffusion performance that exhibits uniform haze in the plane can be obtained, and the color cast of the mini / micro LED display device can be reduced. preferred. The shape of the light diffusing fine particles can be spherical, flat, or irregular, for example. The light diffusing fine particles may be used alone or in combination of two or more.

The average particle diameter of the light diffusing fine particles is preferably 0.1 μm or more, more preferably 0.15 μm or more, still more preferably 0.2 μm or more, and particularly preferably from the viewpoint of imparting appropriate light diffusion performance to the diffusion layer. is 0.25 μm or more. In addition, 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 from the viewpoint of preventing the haze value from becoming too high and displaying high-definition images. It is below. The average particle size can be measured using, for example, a Coulter Counter.

The refractive index of the light diffusing fine particles is preferably 1.2-5, more preferably 1.25-4.5, and may be 1.3-4, or 1.35-3.

The absolute value of the refractive index difference between the light diffusing fine particles and the resin layer composing the diffusion layer (the resin layer excluding the light diffusing fine particles in the diffusion layer) makes the color cast of the mini/micro LED display device more efficient. From the viewpoint of reducing the may The absolute value of the refractive index difference between the light diffusing fine particles and the resin layer is preferably 5 or less, more preferably 5 or less, more preferably from the viewpoint of preventing the haze value from becoming too high and displaying high-definition images. It is 4 or less, more preferably 3 or less.

The content of the light diffusing fine particles in the diffusion layer is preferably 0.01 parts by weight or more with respect to 100 parts by weight of the resin constituting the resin layer, from the viewpoint of imparting appropriate light diffusion performance to the diffusion layer. More preferably 0.05 parts by weight or more, still more preferably 0.1 parts by weight or more, and particularly preferably 0.15 parts by weight or more. In addition, the content of the light diffusing fine particles is preferably 80 parts by weight with respect to 100 parts by weight of the resin constituting the resin layer from the viewpoint of preventing the haze value from becoming too high and displaying a high-definition image. or less, more preferably 70 parts by weight or less.

Examples of the resin layer constituting the diffusion layer include an ionizing radiation-curable resin layer and an adhesive layer. When the resin layer is composed of an ionizing radiation-curable resin layer, examples of ionizing radiation include ultraviolet rays, visible light, infrared rays, and electron beams. Ultraviolet rays are preferred, and therefore, it is preferably composed of an ultraviolet curable resin layer. Examples of UV curable resins include acrylic resins, aliphatic (for example, polyolefin) resins, and urethane resins.

The diffusion layer of the invention is preferably an adhesive layer. When the diffusion layer is composed of an adhesive layer, the steps of the optical semiconductor elements arranged on the substrate of the mini/micro LED display device are filled with the diffusion layer and/or the antireflection layer without gaps, thereby absorbing the steps. It is preferable in that it is excellent and can prevent display unevenness. The pressure-sensitive adhesive layer includes a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition selected from photocurable pressure-sensitive adhesive compositions and solvent-based pressure-sensitive adhesive compositions. The pressure-sensitive adhesive layer is preferably a pressure-sensitive adhesive layer formed from a photo-curable pressure-sensitive adhesive composition in terms of excellent step absorbability and excellent workability.

The photocurable pressure-sensitive adhesive composition contains a polymer, a photopolymerizable compound, and a photopolymerization initiator. That is, the photocurable pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer contains a polymer, a photopolymerizable compound, and a photopolymerization initiator.

The pressure-sensitive adhesive layer formed using the photocurable pressure-sensitive adhesive composition is a type that performs photocuring (first form), and a type that does not perform photocuring and performs photocuring after bonding with a display panel described later. It is roughly divided into type (second form).

[First form]
The pressure-sensitive adhesive layer of the first form is formed by applying a photocurable pressure-sensitive adhesive composition containing a polymer, a photopolymerizable compound, and a photopolymerization initiator onto a release film and performing photocuring. can do.

(polymer)
Base polymers contained in the photocurable pressure-sensitive adhesive composition include acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate/vinyl chloride copolymers, modified polyolefins, epoxy-based, fluorine-based, and natural polymers. Polymers such as rubbers such as rubbers and synthetic rubbers can be used. In particular, acrylic polymers are suitable because they exhibit moderate wettability, cohesiveness, adhesive properties, etc., are excellent in weather resistance and heat resistance, etc., and have a wide variety of monomers and a high design margin. used for

The acrylic polymer contains a (meth)acrylic acid alkyl ester as a main constituent monomer component. In addition, in this specification, "(meth)acryl" means acryl and/or methacryl. The amount of (meth)acrylic acid alkyl ester is preferably 50% by weight or more, more preferably 55% by weight or more, and still more preferably 60% by weight or more, relative to the total amount of monomer components constituting the acrylic polymer.

As the (meth)acrylic acid alkyl ester, a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms is preferably used. The (meth)acrylic acid alkyl ester may have a branched alkyl group or a cyclic alkyl group.

Specific examples of (meth)acrylic acid alkyl esters having a chain alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, and (meth)acrylate. s-butyl acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate , undecyl (meth)acrylate, dodecyl (meth)acrylate, isotridecyl (meth)acrylate, tetradecyl (meth)acrylate, isotetradecyl (meth)acrylate, pentadecyl (meth)acrylate, (meth)acrylic acid cetyl, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isooctacyl (meth)acrylate, nonadecyl (meth)acrylate and the like. Preferred alkyl (meth)acrylates having a chain alkyl group used in the first embodiment include butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octadecyl (meth)acrylate, and (meth)acrylic acid. dodecyl acid. The amount of (meth)acrylic acid alkyl ester having a chain alkyl group with respect to the total amount of monomer components constituting the acrylic polymer is, for example, about 40 to 90% by weight, and 45 to 80% by weight or 50 to 70% by weight. There may be.

Specific examples of (meth)acrylic acid alkyl esters having an alicyclic alkyl group include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate. (meth) acrylic acid cycloalkyl ester; (meth) acrylic acid ester having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth) acrylate; dicyclopentanyl (meth) acrylate, dicyclopentanyloxy Tricyclics such as ethyl (meth)acrylate, tricyclopentanyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate (Meth)acrylic acid esters having the above aliphatic hydrocarbon ring can be mentioned. Preferred alkyl (meth)acrylates having an alicyclic alkyl group used in the first embodiment are cyclohexyl (meth)acrylate and isobornyl (meth)acrylate. The amount of (meth)acrylic acid alkyl ester having an alicyclic alkyl group relative to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, 5 to 40% by weight or 10 to 30% by weight. may be

The acrylic polymer may contain polar group-containing monomers such as hydroxyl group-containing monomers, carboxy group-containing monomers, and nitrogen-containing monomers as constituent monomer components. By including a polar group-containing monomer as a constituent monomer component of the acrylic polymer, the cohesive force of the pressure-sensitive adhesive tends to be enhanced and the adhesive force tends to be improved. Preferred polar group-containing monomers used in the first embodiment are hydroxyl group-containing monomers and nitrogen-containing monomers, and more preferably hydroxyl group-containing monomers. The amount of the polar group-containing monomer (the sum of the hydroxyl group-containing monomer, the carboxy group-containing monomer, and the nitrogen-containing monomer) relative to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and 5 to 40% by weight. % or 10-30% by weight.

Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and (meth)acrylic acid. (Meth)acrylic acid esters such as 8-hydroxyoctyl acid, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate and (4-hydroxymethylcyclohexyl)-methyl (meth)acrylate . When the isocyanate cross-linking agent introduces a cross-linked structure into the polymer, the hydroxyl group can become a reaction point (cross-linking point) with the isocyanate group. Preferred hydroxyl group-containing monomers used in the first embodiment are 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate. The amount of the hydroxyl group-containing monomer relative to the total amount of monomer components constituting the acrylic polymer is, for example, approximately 3 to 50% by weight, and may be 5 to 40% by weight or 10 to 30% by weight.

Carboxy group-containing monomers include acrylic monomers such as (meth)acrylic acid, carboxyethyl (meth)acrylate, and carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and the like. . When the epoxy-based cross-linking agent introduces a cross-linked structure into the polymer, the carboxy group can serve as a reaction point (cross-linking point) with the epoxy group. A preferred carboxy group-containing monomer used in the first embodiment is (meth)acrylic acid. The amount of the carboxy group-containing monomer relative to the total amount of monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and may be 5 to 40% by weight or 10 to 30% by weight.

Nitrogen-containing monomers include N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, (meth)acryloylmorpholine, N-vinyl Vinyl monomers such as carboxylic acid amides, N-vinylcaprolactam and acrylamide, and cyano group-containing monomers such as acrylonitrile and methacrylonitrile can be used. A preferred nitrogen-containing monomer for use in the first form is N-vinylpyrrolidone. The amount of the nitrogen-containing monomer relative to the total amount of monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and may be 5 to 40% by weight or 10 to 30% by weight.

The acrylic polymer contains, as monomer components other than the above (sometimes referred to as "other monomers"), an acid anhydride group-containing monomer, a caprolactone adduct of (meth)acrylic acid, a sulfonic acid group-containing monomer, and a phosphoric acid group-containing monomer. monomers, vinyl-based monomers such as vinyl acetate, vinyl propionate, styrene, α-methylstyrene; epoxy group-containing monomers such as glycidyl (meth)acrylate; polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, Glycol-based acrylic ester monomers such as methoxyethylene glycol (meth)acrylate and methoxypolypropylene glycol (meth)acrylate; tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth)acrylate, (meth)acryl Acrylic ester monomers such as substituted or unsubstituted aralkyl (meth)acrylates such as 2-methoxyethyl acid, 3-phenoxybenzyl (meth)acrylate, and benzyl (meth)acrylate may also be included. The amount of other monomers relative to the total amount of monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and may be 5 to 40% by weight or 10 to 30% by weight.

The glass transition temperature (Tg) of the polymer contained in the photocurable pressure-sensitive adhesive composition is preferably 0°C or lower. The glass transition temperature of the polymer may be -5°C or lower, -10°C or lower, or -15°C or lower. The glass transition temperature of a polymer is the peak top temperature of the loss tangent (tan δ) determined by dynamic viscoelasticity measurements. When a crosslinked structure is introduced into the polymer, the glass transition temperature can be calculated based on the theoretical Tg from the composition of the polymer. The theoretical Tg is calculated by the following Fox formula.

1/Tg=Σ(W _i /Tg _i )
Tg: glass transition temperature of the copolymer (unit: K)
W _i : weight fraction of monomer i in the copolymer (copolymerization ratio based on weight)
Tg _i : glass transition temperature of homopolymer of monomer i (unit: K)

A polymer is obtained by polymerizing the above monomer components by various known methods. Although the polymerization method is not particularly limited, it is preferable to prepare the polymer by photopolymerization. Since a polymer can be prepared by photopolymerization without using a solvent, it is not necessary to remove the solvent by drying when forming the pressure-sensitive adhesive layer, and a thick pressure-sensitive adhesive layer can be uniformly formed.

In the preparation of the pressure-sensitive adhesive layer of the first mode, it is preferable to prepare a low polymerization degree polymer (prepolymer) in which a part of the monomer components remain unreacted. The composition used for preparing the prepolymer (prepolymer-forming composition) preferably contains a photopolymerization initiator in addition to the monomers. A photopolymerization initiator may be appropriately selected according to the type of monomer. For example, a radical photopolymerization initiator is used for polymerization of an acrylic polymer. Examples of photopolymerization initiators include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, Examples include benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and acylphosphine oxide-based photopolymerization initiators.

In the polymerization, a chain transfer agent, a polymerization inhibitor (polymerization retarder), or the like may be used for the purpose of molecular weight adjustment or the like. Chain transfer agents include thiols such as α-thioglycerol, lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, 2,3-dimercapto-1-propanol, Examples include α-methylstyrene dimer and the like.

Although the polymerization rate of the prepolymer is not particularly limited, it is preferably 3 to 50% by weight, more preferably 5 to 40% by weight, from the viewpoint of obtaining a viscosity suitable for coating on a substrate. The polymerization rate of the prepolymer can be adjusted within a desired range by adjusting the type and amount of the photopolymerization initiator used, and the irradiation intensity and irradiation time of actinic rays such as UV light. The polymerization rate of the prepolymer is the non-volatile content when heated at 130° C. for 3 hours, and is calculated by the following formula. The rate of polymerization (non-volatile content) of the pressure-sensitive adhesive layer is also measured by the same method.
Polymerization rate (%) = weight after heating/weight before heating x 100

As described above, the photocurable pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer contains a polymer, a photopolymerizable compound, and a photopolymerization initiator. For example, a photocurable pressure-sensitive adhesive composition can be obtained by adding a photopolymerizable compound and a photopolymerization initiator to a prepolymer. Instead of using a prepolymer, a low-molecular-weight polymer (oligomer) may be used, and a photopolymerizable compound and a photopolymerization initiator may be mixed with the low-molecular-weight polymer to prepare a photocurable pressure-sensitive adhesive composition. .

(Photopolymerizable compound)
The photopolymerizable compound contained in the photocurable pressure-sensitive adhesive composition has one or more photopolymerizable functional groups in one molecule. The photopolymerizable functional group may be either radically polymerizable, cationic polymerizable or anionic polymerizable. is preferred.

A prepolymer contains a polymer and unreacted monomers, and the unreacted monomers retain photopolymerizability. Therefore, it is not always necessary to add a photopolymerizable compound in the preparation of the photocurable pressure-sensitive adhesive composition. When a photopolymerizable compound is added to the prepolymer, the photopolymerizable compound to be added may be the same as or different from the monomer used for preparing the prepolymer.

When the polymer is an acrylic polymer, the compound to be added as the photopolymerizable compound is preferably a monomer or oligomer having a (meth)acryloyl group as the photopolymerizable functional group, since it has high compatibility with the polymer. The photopolymerizable compound may be a polyfunctional compound having two or more photopolymerizable functional groups in one molecule. A polyfunctional (meth)acrylate is mentioned as a photopolymerizable polyfunctional compound. Polyfunctional (meth)acrylates include polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, bisphenol A ethylene oxide-modified di(meth)acrylate, bisphenol A propylene oxide Modified di(meth)acrylate, alkanediol di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, pentaerythritol di(meth)acrylate, neopentyl glycol di(meth)acrylate, glycerin di(meth)acrylate , urethane di(meth)acrylate and the like; trifunctional (meth)acrylates such as pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, and ethoxylated isocyanurate tri(meth)acrylate; meth)acrylic acid ester; tetrafunctional (meth)acrylic acid ester such as ditrimethylolpropane tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate; dipentaerythritol penta Penta- or higher-functional (meth)acrylic acid esters such as (meth)acrylates and dipentaerythritol hexa(meth)acrylates can be mentioned.

When a polyfunctional compound is used as the photopolymerizable compound, the amount of the polyfunctional compound used is preferably 10 parts by weight or less, more preferably 0.001 to 1 weight part per 100 parts by weight of the polymer (including the prepolymer). parts, more preferably 0.005 to 0.5 parts by weight. If the amount of polyfunctional monomer used is excessively large, the adhesive layer after photocuring may have low viscosity and poor adhesion. The amount of polyfunctional compound used may be 10 parts by weight or less, 5 parts by weight or less, 3 parts by weight or less, or 1 part by weight or less. The amount of polyfunctional monomer used may be 0, 0.001 parts by weight or more, 0.01 parts by weight or more, or 0.1 parts by weight or more.

When a monomer forming a prepolymer is used as the photopolymerizable compound, a hydroxyl group-containing monomer is preferable, and 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are more preferable. When a hydroxyl group-containing monomer is used as the photopolymerizable compound, the amount of the hydroxyl group-containing monomer used is preferably 40 parts by weight or less, more preferably 1 to 30 parts by weight, based on 100 parts by weight of the polymer (including the prepolymer). Yes, more preferably 5 to 20 parts by weight. The amount of the hydroxyl group-containing monomer used may be 40 parts by weight or less, 30 parts by weight or less, or 20 parts by weight or less. The amount of the hydroxyl group-containing monomer used may be 0, or may be 1 part by weight or more, 5 parts by weight or more, or 10 parts by weight or more.

(Photoinitiator)
A photocurable adhesive composition contains a photoinitiator. The photopolymerization initiator generates radicals, acids, bases, etc. by irradiation with actinic rays such as ultraviolet rays, and can be appropriately selected according to the type of the photopolymerizable compound. When the photopolymerizable compound is a compound having a (meth)acryloyl group (for example, a monofunctional or polyfunctional (meth)acrylate), a photoradical polymerization initiator is preferably used as the photopolymerization initiator. A photoinitiator may be used individually and may be used in mixture of 2 or more types.

When the photopolymerization initiator used in the preparation (polymerization) of the polymer (including the prepolymer) remains without being deactivated, the addition of the photopolymerization initiator may be omitted. When adding a photoinitiator to the polymer, the added photoinitiator may be the same as or different from the photoinitiator used in the preparation of the polymer.

The content of the photopolymerization initiator in the photocurable pressure-sensitive adhesive composition is 0.01 to 10 parts by weight with respect to 100 parts by weight of the total amount of monomers (monomers used for polymer preparation and photopolymerizable compounds added to the polymer). about 0.05 to 5 parts by weight.

(Silane coupling agent)
The photocurable pressure-sensitive adhesive composition may contain a silane coupling agent as long as the effects of the present invention are not impaired. When the photocurable pressure-sensitive adhesive composition contains a silane coupling agent, the adhesion reliability to glass (in particular, the adhesion reliability to glass under a high-temperature and high-humidity environment) is improved, which is preferable.

Examples of the silane coupling agent include, but are not limited to, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-aminopropyltrimethoxysilane. , 3-acryloxypropyltrimethoxysilane and the like are preferred. Among them, γ-glycidoxypropyltrimethoxysilane is preferred. Further, as a commercially available product, for example, trade name "KBM-403" (manufactured by Shin-Etsu Chemical Co., Ltd.) can be mentioned. In addition, a silane coupling agent may be used individually or in combination of 2 or more types.

The content of the silane coupling agent in the photocurable pressure-sensitive adhesive composition is not particularly limited, but is preferably 0.01 to 1 part by weight, more preferably 0.03 to 0.5 parts by weight, with respect to 100 parts by weight of the polymer. weight part.

(other ingredients)
In the first mode, the photocurable pressure-sensitive adhesive composition may contain components other than the polymer, the photopolymerizable compound, and the photopolymerization initiator. For example, a chain transfer agent may be included for the purpose of adjusting the photocuring speed. Moreover, an oligomer or a tackifier may be contained for the purpose of adjusting the viscosity of the photocurable pressure-sensitive adhesive composition and adjusting the adhesive strength of the pressure-sensitive adhesive layer. As the oligomer, for example, one having a weight average molecular weight of about 1,000 to 30,000 is used. As the oligomer, an acrylic oligomer is preferable because of its excellent compatibility with the acrylic polymer. The photocurable pressure-sensitive adhesive composition may contain additives such as plasticizers, softeners, antidegradants, fillers, antioxidants, surfactants, antistatic agents, and colorants.

[Second form]
The pressure-sensitive adhesive layer of the second form is a type of pressure-sensitive adhesive layer that does not undergo photocuring, and is formed by forming a photocurable pressure-sensitive adhesive composition into a sheet. Since the adhesive layer of the second form contains the photopolymerizable compound in an unreacted state, the adhesive layer has photocurability.

The photocurable pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer of the second mode contains a polymer, a photopolymerizable compound, and a photopolymerization initiator.

(polymer)
As the polymer contained in the pressure-sensitive adhesive composition, as in the first embodiment, various polymers can be applied, and an acrylic polymer is preferably used. The monomer components constituting the acrylic polymer are the same as in the first embodiment.

In order to introduce a crosslinked structure using a crosslinking agent, which will be described later, the monomer component constituting the polymer preferably contains a hydroxy group-containing monomer and/or a carboxy group-containing monomer. For example, when using an isocyanate-based cross-linking agent, it is preferable to contain a hydroxy group-containing monomer as a monomer component. When an epoxy-based cross-linking agent is used, it preferably contains a carboxy group-containing monomer as a monomer.

In the second form, since photocuring is not performed on the base material, in order to form a solid (regular) pressure-sensitive adhesive layer, the polymer contained in the photocurable pressure-sensitive adhesive composition should have a relatively large molecular weight. Used. The weight average molecular weight of the polymer is, for example, about 100,000 to 2,000,000.

Since high-molecular-weight polymers are solid, the pressure-sensitive adhesive composition is preferably a solution in which the polymer is dissolved in an organic solvent. For example, a polymer solution is obtained by solution polymerization of the monomer components. A polymer solution may be prepared by dissolving a solid polymer in an organic solvent.

Ethyl acetate, toluene and the like are generally used as solvents for solution polymerization. The solution concentration is usually about 20 to 80% by weight. Examples of polymerization initiators include azo initiators, peroxide initiators, redox initiators obtained by combining peroxides and reducing agents (for example, combinations of persulfate and sodium hydrogen sulfite, peroxides and ascorbic A thermal polymerization initiator such as a combination of sodium phosphates) is preferably used. The amount of the polymerization initiator used is not particularly limited, but for example, it is preferably about 0.005 to 5 parts by weight, more preferably about 0.02 to 3 parts by weight, relative to 100 parts by weight of the total amount of the monomer components forming the polymer. preferable.

(Photopolymerizable compound)
The photopolymerizable compound contained in the pressure-sensitive adhesive composition in the second mode is the same as described above for the first mode, and a compound having one or more photopolymerizable functional groups is used.

(Photoinitiator)
The photopolymerization initiator contained in the pressure-sensitive adhesive composition in the second mode is the same as that described in the first mode, and preferably has an absorption maximum in the wavelength region of 330 to 400 nm. The amount of the photopolymerization initiator is about 0.01 to 10 parts by weight, preferably about 0.05 to 5 parts by weight, per 100 parts by weight of the polymer.

(crosslinking agent)
The second form of pressure-sensitive adhesive composition preferably contains a cross-linking agent capable of cross-linking with the above polymer. Specific examples of cross-linking agents for introducing a cross-linked structure into a polymer include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, carbodiimide-based cross-linking agents, and metal chelate-based cross-linking agents. be done. Among these, isocyanate-based cross-linking agents and epoxy-based cross-linking agents are preferred because they are highly reactive with hydroxyl groups and carboxy groups of polymers and facilitate the introduction of a cross-linked structure. These cross-linking agents react with functional groups such as hydroxyl groups and carboxy groups introduced into the polymer to form cross-linked structures.

A polyisocyanate having two or more isocyanate groups in one molecule is used as the isocyanate-based cross-linking agent. Examples of isocyanate-based cross-linking agents include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; Aromatic isocyanates such as isocyanate, 4,4′-diphenylmethane diisocyanate, and xylylene diisocyanate; trimethylolpropane/tolylene diisocyanate trimer adduct (for example, “Coronate L” manufactured by Tosoh), trimethylolpropane/hexamethylene Diisocyanate trimer adduct (e.g., Tosoh "Coronate HL"), trimethylolpropane adduct of xylylene diisocyanate (e.g., Mitsui Chemicals "Takenate D110N", isocyanurate of hexamethylene diisocyanate (e.g., Tosoh " and isocyanate adducts such as "Coronate HX").

A polyfunctional epoxy compound having two or more epoxy groups in one molecule is used as the epoxy-based cross-linking agent. The epoxy group of the epoxy-based cross-linking agent may be a glycidyl group. Examples of epoxy-based cross-linking agents include N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1, 6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, penta erythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipate diglycidyl ester, o-phthalate diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether and the like. As the epoxy-based cross-linking agent, commercially available products such as "Denacol" manufactured by Nagase ChemteX, "Tetrad X" and "Tetrad C" manufactured by Mitsubishi Gas Chemical may be used.

The amount of the cross-linking agent is about 0.01 to 5 parts by weight with respect to 100 parts by weight of the polymer, and may be 0.05 parts by weight or more, 0.1 parts by weight or more, or 0.2 parts by weight or more. , 3 parts by weight or less, 2 parts by weight or less, or 1 part by weight or less.

(other ingredients)
In addition to the above components, the pressure-sensitive adhesive composition of the second form contains an oligomer, a tackifier, a silane coupling agent, a chain transfer agent, a plasticizer, a softening agent, an anti-degradation agent, a filler, an antioxidant, and a surfactant. agents, antistatic agents, colorants, and the like.

The pressure-sensitive adhesive layer may be a pressure-sensitive adhesive layer (third mode) formed from a solvent-based pressure-sensitive adhesive composition. The solvent-based pressure-sensitive adhesive composition contains at least a polymer and a solvent, and may contain a cross-linking agent. That is, the solvent-based pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer of the third mode contains a polymer, a solvent, and optionally a cross-linking agent.

[Third form]
The pressure-sensitive adhesive layer of the third form is formed by applying a solvent-based pressure-sensitive adhesive composition containing a polymer, a solvent, and optionally a cross-linking agent onto the release film and removing the solvent by drying. can do.

The solvent-based pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer of the third mode contains a polymer, a solvent, and optionally a cross-linking agent.

(polymer)
As the polymer contained in the solvent-based pressure-sensitive adhesive composition, various polymers can be applied as in the first embodiment, and an acrylic polymer is preferably used. The monomer components constituting the acrylic polymer are the same as in the first embodiment.

In the third embodiment, a polymer having a relatively large molecular weight is used as the polymer contained in the solvent-based pressure-sensitive adhesive composition in order to form a solid (regular) pressure-sensitive adhesive layer on the substrate. The weight average molecular weight of the polymer is, for example, about 100,000 to 2,000,000.

(solvent)
Since the polymer in the third form is solid, the solvent-based pressure-sensitive adhesive composition is a solution in which the polymer is dissolved in an organic solvent. For example, a polymer solution is obtained by solution polymerization of the monomer components. A polymer solution may be prepared by dissolving a solid polymer in an organic solvent.

Ethyl acetate, toluene and the like are generally used as the solvent. The solution concentration is usually about 20 to 80% by weight.

Polymerization initiators for solution polymerization of monomer components include azo initiators, peroxide initiators, redox initiators combining peroxides and reducing agents (for example, persulfate and sodium hydrogen sulfite combination, combination of peroxide and sodium ascorbate) and the like are preferably used. The amount of the polymerization initiator used is not particularly limited, but for example, it is preferably about 0.005 to 5 parts by weight, more preferably about 0.02 to 3 parts by weight, relative to 100 parts by weight of the total amount of the monomer components forming the polymer. preferable.

(crosslinking agent)
The solvent-based pressure-sensitive adhesive composition of the third form may contain a cross-linking agent capable of cross-linking with the above polymer. In addition, when the solvent-based pressure-sensitive adhesive composition contains a (meth)acrylic block copolymer, the pressure-sensitive adhesive layer of the third form has sufficient shape stability and thus does not need to contain a cross-linking agent.

When the solvent-based pressure-sensitive adhesive composition contains a cross-linking agent in the third mode, the cross-linking agent is the same as that described above for the second mode, and is preferably an isocyanate-based cross-linking agent or an epoxy-based cross-linking agent.

In the third embodiment, when the solvent-based pressure-sensitive adhesive composition contains a cross-linking agent, the content thereof is about 0.01 to 5 parts by weight, 0.05 parts by weight or more, and 0.05 part by weight or more, based on 100 parts by weight of the polymer. It may be 1 part by weight or more, or 0.2 parts by weight or more, and may be 3 parts by weight or less, 2 parts by weight or less, or 1 part by weight or less.

(other ingredients)
In addition to the above components, the solvent-based pressure-sensitive adhesive composition of the third form contains an oligomer, a tackifier, a silane coupling agent, a chain transfer agent, a plasticizer, a softening agent, a deterioration inhibitor, a filler, an antioxidant, Surfactants, antistatic agents, colorants and the like may also be included.

<Antireflection layer>
The antireflection layer of the present invention is a layer having an antireflection function of light, specifically, an antireflection function of metal wiring in a mini/micro LED display device, and is preferably composed of a resin layer. The antireflection layer of the present invention is not limited as long as it has a function of preventing reflection of light, but it preferably contains a colorant dispersed or dissolved in the resin layer.

The haze value of the antireflection layer of the present invention is not particularly limited, but is preferably 30% or less, more preferably 25% or less, still more preferably 20% or less from the viewpoint of ensuring the visibility of the mini/micro LED display device. , particularly preferably 15% or less. In addition, the haze value of the antireflection layer of the present invention is preferably 1% or more, more preferably 3% or more, and still more preferably 5% or more, from the viewpoint of efficiently reducing the color cast of the mini/micro LED display device. , particularly preferably 8% or more, and may be 10% or more.

The total light transmittance of the antireflection layer of the present invention is not particularly limited, but is preferably 30% or less, more preferably 30% or less, from the viewpoint of further improving the antireflection function of metal wiring and the like in the mini/micro LED display device and the contrast. is 25% or less, more preferably 20% or less, particularly preferably 10% or less. In addition, the total light transmittance of the antireflection layer of the present invention is preferably 0.5% or more, more preferably 1% or more, still more preferably 1% or more, from the viewpoint of ensuring the brightness of the mini/micro LED display device. is 1.5% or more, particularly preferably 2% or more, and may be 2.5% or more, or 3% or more.

The haze value and total light transmittance of the antireflection layer of the present invention can be measured by the methods defined in JIS 7136 and JIS 7361, respectively. It can be controlled by the diffusible fine particles, the kind and blending amount of the colorant described later, and the like.

The thickness of the antireflection layer of the present invention is preferably 10 to 300 μm, more preferably 15 to 250 μm, from the viewpoint of further improving the antireflection function and contrast of metal wiring in a mini/micro LED display device. It is more preferably 20 to 200 μm, more preferably 25 to 150 μm, further preferably 30 to 100 μm.

Examples of the resin layer constituting the antireflection layer include an ionizing radiation-curable resin layer and an adhesive layer. As the ionizing radiation-curable resin layer and the adhesive layer, the same ionizing radiation-curable resin layer and adhesive layer as those constituting the diffusion layer can be used. The steps of the optical semiconductor elements arranged on the substrate of the mini/micro LED display device are filled with the diffusion layer and/or the antireflection layer without any gaps, so that they are excellent in step absorption and can prevent display unevenness. It is preferred that the layer is composed of an adhesive layer.

The diffusing layer and/or the antireflection layer fills the steps of the optical semiconductor elements arranged on the substrate of the mini/micro LED display device without gaps, has excellent step absorption, and can prevent display unevenness. and the antireflection layer are preferably pressure-sensitive adhesive layers. The antireflection layer may be composed of the same resin layer as the diffusion layer, or may be composed of a different resin layer.

The coloring agent imparts light-shielding properties to the antireflection layer and imparts antireflection performance. If the antireflection layer contains a coloring agent, the transmittance to light is lowered, and it is preferable for the above T ₁ and the above T ₂ to satisfy T ₁ >T ₂ . The antireflection layer seals between the metal wiring layer of the self-luminous display device (mini/micro LED display device) and the LED chip, thereby preventing reflection due to the metal wiring and preventing color mixing between the LED chips. , the contrast of the image is improved.

The colorant may be either a dye or a pigment as long as it can be dissolved or dispersed in the antireflection layer. Dyes are preferred because they can achieve a low haze even when added in small amounts, and are easy to distribute uniformly without sedimentation like pigments. Pigments are also preferred because they have high color development even when added in small amounts. If a pigment is used as the colorant, it preferably has low or no conductivity.

Although the coloring agent is not particularly limited, one that absorbs visible light and has ultraviolet transparency is preferable. That is, the colorant preferably has a higher average transmittance at wavelengths of 330 to 400 nm than at wavelengths of 400 to 700 nm. Further, the colorant preferably has a maximum transmittance at a wavelength of 330 to 400 nm larger than a maximum transmittance at a wavelength of 400 to 700 nm. The transmittance of the colorant is adjusted by an appropriate solvent such as tetrahydrofuran (THF) or a dispersion medium (organic solvent with low absorption in the wavelength range of 330 to 700 nm) so that the transmittance at a wavelength of 400 nm is about 50 to 60%. Measure using diluted solutions or dispersions.

Examples of ultraviolet-transmitting black pigments that absorb ultraviolet light less than that of visible light include "9050BLACK" and "UVBK-0001" manufactured by Tokushiki. Examples of the ultraviolet-transmitting black dye include "SOC-L-0123" manufactured by Orient Chemical Industry Co., Ltd., and the like.

Carbon black and titanium black, which are generally used as black colorants, absorb more ultraviolet light than visible light (the transmittance of ultraviolet light is smaller than the transmittance of visible light). Therefore, when a coloring agent such as carbon black is added to a photocurable pressure-sensitive adhesive composition sensitive to ultraviolet rays, most of the ultraviolet rays irradiated for photocuring are absorbed by the coloring agent, and the amount of light absorbed by the photopolymerization initiator is is small, and photocuring takes time (accumulated amount of irradiation light increases). In addition, when the thickness of the pressure-sensitive adhesive layer is large, less ultraviolet rays reach the surface opposite to the light irradiation surface, so that photocuring tends to be insufficient even if light irradiation is performed for a long time. On the other hand, by using a coloring agent having a higher transmittance for ultraviolet light than for visible light, inhibition of curing due to the coloring agent can be suppressed.

The content of the coloring agent in the antireflection layer is preferably 0.01 to 20 parts by weight with respect to 100 parts by weight of the resin constituting the resin layer from the viewpoint of imparting appropriate antireflection performance to the antireflection layer. It is more preferably 0.1 to 15 parts by weight, still more preferably 1 to 10 parts by weight, and may be appropriately set according to the type of colorant, color tone and light transmittance of the pressure-sensitive adhesive layer, and the like. Colorants may be added to the composition as a solution or dispersion dissolved or dispersed in a suitable solvent.

<Base material>
The base material that the sheet for optical semiconductor element encapsulation of the present invention may have as other layers is not particularly limited, and examples thereof include glass and transparent plastic film base materials. The transparent plastic film substrate is not particularly limited, but preferably has excellent visible light transmittance and excellent transparency (preferably haze value of 5% or less). and the transparent plastic film substrate described in . As the transparent plastic film substrate, one having optically low birefringence is preferably used. The base material can also be used, for example, as a cover member of a self-luminous display device. A film formed of polyolefin or the like having a norbornene structure is preferred. With such a configuration, the step of separately laminating the cover member in the manufacture of the self-luminous display device can be eliminated, so the number of steps and required members can be reduced, and the production efficiency can be improved. Moreover, with such a configuration, the thickness of the cover member can be reduced. In addition, when the base material is the cover member, it becomes the outermost surface of the self-luminous display device.

The total light transmittance of the substrate is not particularly limited, but is, for example, 85 to 100%, and may be 88% or more, 90% or more, or 92% or more.

The thickness of the substrate is not particularly limited, but is preferably in the range of 10 to 500 μm, more preferably in the range of 20 to 300 μm, in consideration of workability such as strength, handleability, and thin layer properties. , optimally in the range of 30-200 μm. The refractive index of the substrate is not particularly limited, but is, for example, in the range of 1.30 to 1.80, preferably in the range of 1.40 to 1.70.

The substrate is preferably subjected to reflective surface treatment and/or anti-glare treatment. When the base material is subjected to reflective surface treatment and / or anti-glare treatment, it becomes the outermost surface of the self-luminous display device, preventing deterioration of visibility due to reflection of external light and reflection of images, or glossiness You can adjust the appearance such as Anti-glare treatments are preferred as they are easy to manufacture and low in cost.

As the antireflection treatment, any known antireflection treatment can be used without particular limitation, and examples thereof include antireflection (AR) treatment.

As the antireflection (AR) treatment, a known AR treatment can be applied without particular limitation. It can be carried out by forming an anti-reflection layer (AR layer) in which more than one layer is laminated. The AR layer exerts an antireflection function by canceling out the reversed phases of the incident light and the reflected light using the interference effect of light. The wavelength region of visible light that exhibits the antireflection function is, for example, 380 to 780 nm, and the wavelength region with particularly high luminosity is in the range of 450 to 650 nm. It is preferable to design the AR layer so that

The AR layer generally includes a multilayer antireflection layer having a structure in which two to five optical thin layers (thin films with strictly controlled thickness and refractive index) are laminated. By forming multiple layers with a thickness of , the degree of freedom in the optical design of the AR layer increases, the anti-reflection effect can be further improved, and the spectral reflection characteristics can be made uniform (flat) in the visible light region. become. Since the optical thin film requires high thickness accuracy, each layer is generally formed by dry methods such as vacuum deposition, sputtering, and CVD.

As the anti-glare (AG) treatment, any known AG treatment can be applied without particular limitation, and can be carried out, for example, by forming an anti-glare layer on the substrate. As the anti-glare layer, known layers can be employed without limitation, and it is generally formed as a layer in which inorganic or organic particles are dispersed as an anti-glare agent in a resin.

In the present embodiment, the antiglare layer is formed using an antiglare layer-forming material containing a resin, particles, and a thixotropy-imparting agent. A shape is formed. With this configuration, the anti-glare layer has excellent display characteristics that achieve both anti-glare properties and prevention of white blurring, and despite the fact that the anti-glare layer is formed using aggregation of particles, there are no defects in appearance. It is possible to prevent the occurrence of protrusions on the surface of the anti-glare layer and improve the yield of products.

Examples of the resin include thermosetting resins and ionizing radiation-curable resins that are cured by ultraviolet light or light. As the resin, it is possible to use a commercially available thermosetting resin, ultraviolet curable resin, or the like.

As the thermosetting resin or UV-curable resin, for example, a curable compound having at least one of an acrylate group and a methacrylate group that is cured by heat, light (ultraviolet rays, etc.), electron beams, or the like can be used. Silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, oligomers or prepolymers such as acrylates and methacrylates of polyfunctional compounds such as polyhydric alcohols. can give. These may be used individually by 1 type, and may use 2 or more types together.

For the resin, for example, a reactive diluent having at least one of an acrylate group and a methacrylate group can be used. As the reactive diluent, for example, reactive diluents described in JP-A-2008-88309 can be used, and examples include monofunctional acrylates, monofunctional methacrylates, polyfunctional acrylates, polyfunctional methacrylates, and the like. As the reactive diluent, tri- or more functional acrylates and tri- or more functional methacrylates are preferable. This is because the hardness of the antiglare layer can be made excellent. Examples of the reactive diluent include butanediol glycerol ether diacrylate, isocyanuric acid acrylate, and isocyanuric acid methacrylate. These may be used individually by 1 type, and may use 2 or more types together.

The main functions of the particles for forming the antiglare layer are to make the surface of the formed antiglare layer uneven to impart antiglare properties and to control the haze value of the antiglare layer. The haze value of the antiglare layer can be designed by controlling the refractive index difference between the particles and the resin. Examples of the particles include inorganic particles and organic particles. The inorganic particles are not particularly limited, and examples include silicon oxide particles, titanium oxide particles, aluminum oxide particles, zinc oxide particles, tin oxide particles, calcium carbonate particles, barium sulfate particles, talc particles, kaolin particles, calcium sulfate particles, and the like. is given. The organic particles are not particularly limited, and examples include polymethyl methacrylate resin powder (PMMA fine particles), silicone resin powder, polystyrene resin powder, polycarbonate resin powder, acrylic styrene resin powder, benzoguanamine resin powder, melamine resin powder, polyolefin. Examples thereof include resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, polyethylene fluoride resin powder, and the like. One type of these inorganic particles and organic particles may be used alone, or two or more types may be used in combination.

The weight average particle size (D) of the particles is preferably in the range of 2.5 to 10 μm. By setting the weight-average particle size of the particles within the above range, for example, the anti-glare property is more excellent and white blurring can be prevented. The weight average particle size of the particles is more preferably in the range of 3-7 μm. The weight-average particle diameter of the particles can be measured, for example, by the Coulter counting method. For example, using a particle size distribution measuring device (trade name: Coulter Multisizer, manufactured by Beckman Coulter, Inc.) using the pore electrical resistance method, the volume of the electrolyte solution corresponding to the volume of the particles when the particles pass through the pores. By measuring the electrical resistance, the number and volume of the particles are measured, and the weight average particle diameter is calculated.

The shape of the particles is not particularly limited, and may be, for example, a substantially spherical bead shape, or an irregular shape such as a powder. They are substantially spherical particles with a ratio of 1.5 or less, most preferably spherical particles.

The proportion of the particles in the anti-glare layer is preferably in the range of 0.2 to 12 parts by weight, more preferably in the range of 0.5 to 12 parts by weight, still more preferably 1 to 12 parts by weight, with respect to 100 parts by weight of the resin. It is in the range of 7 parts by weight. By setting it within the above range, for example, it is possible to achieve more excellent anti-glare properties and prevent white blurring.

Examples of the thixotropy imparting agent for forming the antiglare layer include organic clay, polyolefin oxide, modified urea and the like.

The organoclay is preferably an organized clay in order to improve affinity with the resin. Examples of organic clays include layered organic clays. The organic clay may be self-prepared, or a commercially available product may be used. Examples of the commercially available products include Lucentite SAN, Lucentite STN, Lucentite SEN, Lucentite SPN, Somasif ME-100, Somasif MAE, Somasif MTE, Somasif MEE, Somasif MPE (trade names, all of which are manufactured by Co-op Chemical Co., Ltd.). ) manufactured); Organite, Organite D, Organite T (trade names, all manufactured by Hojun Co., Ltd.); Kunipia F, Kunipia G, Kunipia G4 (trade names, manufactured by Kunimine Industry Co., Ltd.); Thixogel VZ, Kraton HT , Kraton 40 (trade name, both manufactured by Rockwood Additives), and the like.

The oxidized polyolefin may be self-prepared or a commercially available product may be used. Examples of the commercially available products include Disparlon 4200-20 (trade name, manufactured by Kusumoto Kasei Co., Ltd.) and Flownon SA300 (trade name, manufactured by Kyoeisha Chemical Co., Ltd.).

The modified urea is a reaction product of an isocyanate monomer or its adduct and an organic amine. The modified urea may be self-prepared, or a commercially available product may be used. Examples of the commercial product include BYK410 (manufactured by Big Chemie).

The thixotropy-imparting agents may be used alone or in combination of two or more.

In this embodiment, it is preferable that the height of the convex portion from the roughness average line of the antiglare layer is less than 0.4 times the thickness of the antiglare layer. More preferably, it is in the range of 0.01 times or more and less than 0.4 times, and still more preferably in the range of 0.01 times or more and less than 0.3 times. Within this range, it is possible to suitably prevent the formation of projections that impair the appearance of the convex portions. The anti-glare layer of the present embodiment has convex portions with such heights, so that it is possible to make appearance defects less likely to occur. Here, the height from the average line can be measured, for example, by the method described in JP-A-2017-138620.

The proportion of the thixotropy imparting agent in the antiglare layer is preferably in the range of 0.1 to 5 parts by weight, more preferably in the range of 0.2 to 4 parts by weight, with respect to 100 parts by weight of the resin.

Although the thickness (d) of the antiglare layer is not particularly limited, it is preferably in the range of 3 to 12 μm. By setting the thickness (d) of the antiglare layer within the above range, for example, it is possible to prevent curling of the sheet for optical semiconductor element encapsulation, and to avoid the problem of reduced productivity such as poor transportability. Further, when the thickness (d) is within the above range, the weight average particle size (D) of the particles is preferably within the range of 2.5 to 10 μm as described above. By combining the thickness (d) of the antiglare layer and the weight average particle diameter (D) of the particles, the antiglare property can be further improved. The thickness (d) of the antiglare layer is more preferably in the range of 3-8 μm.

The relationship between the thickness (d) of the antiglare layer and the weight average particle size (D) of the particles is preferably within the range of 0.3≦D/d≦0.9. By having such a relationship, it is possible to obtain an anti-glare layer that is more excellent in anti-glare properties, can prevent white blurring, and has no defects in appearance.

In the sheet for optical-semiconductor element encapsulation of the present invention, as described above, the anti-glare layer forms projections on the surface of the anti-glare layer due to aggregation of the particles and the thixotropy-imparting agent. In the agglomerated portions forming the convex portions, the particles are present in a plurality of aggregated states in the plane direction of the antiglare layer. As a result, the convex portion has a gentle shape. Since the anti-glare layer of the present embodiment has convex portions having such a shape, it is possible to maintain anti-glare properties, prevent white blurring, and make it difficult for appearance defects to occur. .

The surface shape of the antiglare layer can be arbitrarily designed by controlling the aggregation state of particles contained in the antiglare layer forming material. The aggregation state of the particles can be controlled by, for example, the material of the particles (for example, chemically modified state of the particle surface, affinity for solvent or resin, etc.), type of resin (binder) or solvent, combination, and the like. Here, in the present embodiment, the aggregation state of the particles can be controlled by the thixotropy imparting agent contained in the antiglare layer-forming material. As a result, the aggregated state of the particles can be made as described above, and the convex portion can be formed into a smooth shape.

In the sheet for encapsulating optical semiconductor elements of the present embodiment, when the base material is made of resin or the like, it is preferable that the sheet has a permeation layer at the interface between the base material and the antiglare layer. The permeation layer is formed by permeating the base material with the resin component contained in the material for forming the antiglare layer. The formation of the permeation layer is preferable because the adhesion between the substrate and the antiglare layer can be improved. The penetration layer preferably has a thickness in the range of 0.2 to 3 μm, more preferably in the range of 0.5 to 2 μm. For example, when the base material is triacetyl cellulose and the resin contained in the antiglare layer is an acrylic resin, the permeation layer can be formed. The permeation layer can be confirmed, for example, by observing the cross section of the sheet for optical semiconductor element encapsulation with a transmission electron microscope (TEM), and the thickness can be measured.

In the present embodiment, even when applied to a sheet for optical semiconductor element encapsulation having such a permeation layer, it is possible to easily achieve a desired gentle surface unevenness that achieves both anti-glare properties and prevention of white blurring. can be formed. It is preferable to form the permeation layer thicker in order to improve the adhesion of the base material with poorer adhesion to the anti-glare layer.

In this embodiment, in the antiglare layer, it is preferable that the number of appearance defects having a maximum diameter of 200 μm or more is 1 or less per 1 m ² of the antiglare layer. More preferably, it does not have the appearance defect.

In this embodiment, the base material on which the antiglare layer is formed preferably has a haze value within the range of 0 to 10%. The haze value is a haze value (cloudiness) according to JIS K 7136 (2000 version). The haze value is more preferably in the range of 0 to 5%, still more preferably in the range of 0 to 3%. In order to keep the haze value within the above range, it is preferable to select the particles and the resin such that the refractive index difference between the particles and the resin is in the range of 0.001 to 0.02. When the haze value is within the above range, a clear image can be obtained and the contrast in a dark place can be improved.

In the present embodiment, the uneven shape of the antiglare layer surface preferably has an average inclination angle θa (°) in the range of 0.1 to 5.0, more preferably in the range of 0.3 to 4.5. It is preferably in the range of 1.0 to 4.0, and particularly preferably in the range of 1.6 to 4.0. Here, the average tilt angle θa is a value defined by the following formula (1). The average tilt angle θa is, for example, a value measured by the method described in JP-A-2017-138620.
Average tilt angle θa=tan-1Δa (1)

In the above formula (1), Δa is, as shown in the following formula (2), in the reference length L of the roughness curve defined in JIS B 0601 (1994 edition), the distance between the top and the valley of the adjacent peaks It is a value obtained by dividing the sum (h1+h2+h3 . The roughness curve is a curve obtained by removing surface waviness components longer than a predetermined wavelength from the cross-sectional curve with a phase difference compensation type high-pass filter. Further, the cross-sectional curve is a contour that appears at the cut end when the target plane is cut along a plane perpendicular to the target plane.
Δa=(h1+h2+h3...+hn)/L (2)

When θa is within the above range, the anti-glare property is more excellent, and white blurring can be prevented.

In forming the antiglare layer, the prepared antiglare layer forming material (coating solution) preferably exhibits thixotropy, and the Ti value defined below is in the range of 1.3 to 3.5. is preferred, and more preferably in the range of 1.3 to 2.8.
Ti value = β1/β2
Here, β1 is the viscosity measured at a shear rate of 20 (1/s) using HAAKE's Rheostress 6000, and β2 is the viscosity measured using HAAKE's Rheostress 6000 at a shear rate of 200 (1/s). Viscosity measured under conditions.

If the Ti value is less than 1.3, defects in appearance tend to occur, and anti-glare properties and white blur characteristics deteriorate. On the other hand, when the Ti value exceeds 3.5, the particles are less likely to agglomerate and more likely to be in a dispersed state.

The method for producing the antiglare layer of the present embodiment is not particularly limited and may be produced by any method. For example, an antiglare layer forming material (coating liquid ) is prepared, the antiglare layer-forming material (coating liquid) is applied to the substrate to form a coating film, and the coating film is cured to form an antiglare layer. In this embodiment, a transfer method using a mold, a method of imparting an uneven shape by an appropriate method such as sandblasting or an embossing roll, or the like can be used together.

The solvent is not particularly limited, and various solvents can be used. One type may be used alone, or two or more types may be used in combination. There is an optimum solvent type and solvent ratio depending on the composition of the resin, the types and contents of the particles and the thixotropy-imparting agent, and the like. Examples of solvents include, but are not limited to, alcohols such as methanol, ethanol, isopropyl alcohol, butanol, and 2-methoxyethanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclopentanone; methyl acetate, ethyl acetate. , Esters such as butyl acetate; Ethers such as diisopropyl ether and propylene glycol monomethyl ether; Glycols such as ethylene glycol and propylene glycol; Cellosolves such as ethyl cellosolve and butyl cellosolve; Aliphatic hydrocarbons such as hexane, heptane and octane Aromatic hydrocarbons such as benzene, toluene, and xylene.

For example, when triacetyl cellulose (TAC) is used as the base material to form the permeation layer, a good solvent for TAC can be suitably used. Examples of the solvent include ethyl acetate, methyl ethyl ketone, cyclopentanone and the like.

Further, by appropriately selecting the solvent, the thixotropy of the antiglare layer-forming material (coating liquid) by the thixotropy-imparting agent can be exhibited satisfactorily. For example, when organoclays are used, toluene and xylene can be suitably used alone or in combination. They can be used or used in combination. For example, when modified urea is used, butyl acetate and methyl isobutyl ketone can be preferably used alone or in combination.

Various leveling agents can be added to the antiglare layer-forming material. As the leveling agent, for example, a fluorine-based or silicone-based leveling agent can be used for the purpose of preventing coating unevenness (uniformizing the coated surface). In this embodiment, depending on the case where antifouling property is required on the surface of the antiglare layer, or the case where an antireflection layer (low refractive index layer) or a layer containing an interlayer filler is formed on the antiglare layer, A leveling agent can be appropriately selected. In the present embodiment, for example, the thixotropic property can be expressed in the coating liquid by including the thixotropy-imparting agent, so uneven coating is less likely to occur. For this reason, this embodiment has an advantage that, for example, the options for the leveling agent can be expanded.

The amount of the leveling agent compounded is, for example, 5 parts by weight or less, preferably in the range of 0.01 to 5 parts by weight, per 100 parts by weight of the resin.

Pigments, fillers, dispersants, plasticizers, UV absorbers, surfactants, antifouling agents, antioxidants and the like are added to the antiglare layer-forming material as necessary within a range that does not impair the performance. may These additives may be used singly or in combination of two or more.

Conventionally known photopolymerization initiators, such as those described in JP-A-2008-88309, can be used for the anti-glare layer-forming material.

Examples of methods for applying the anti-glare layer-forming material onto a substrate include coating methods such as fountain coating, die coating, spin coating, spray coating, gravure coating, roll coating, and bar coating. can be used.

The antiglare layer-forming material is applied to form a coating film on the substrate, and the coating film is cured. It is preferable to dry the coating film prior to the curing. The drying may be, for example, natural drying, air drying by blowing air, heat drying, or a combination thereof.

The means for curing the coating film of the anti-glare layer-forming material is not particularly limited, but ultraviolet curing is preferable. The irradiation amount of the energy beam source is preferably 50 to 500 mJ/cm ² as an integrated exposure amount at an ultraviolet wavelength of 365 nm. When the irradiation dose is 50 mJ/cm ² or more, the curing becomes more sufficient, and the hardness of the formed anti-glare layer becomes more sufficient. Also, if it is 500 mJ/cm ² or less, coloring of the formed antiglare layer can be prevented.

As described above, an antiglare layer can be formed on the substrate. The anti-glare layer may be formed by a manufacturing method other than the method described above. The hardness of the antiglare layer of the present embodiment is preferably 2H or higher in terms of pencil hardness, although it is also affected by the thickness of the layer.

In this embodiment, the antiglare layer may have a multi-layer structure in which two or more layers are laminated.

In this embodiment, the above-mentioned AR layer (low refractive index layer) may be arranged on the antiglare layer. For example, when the sheet for encapsulating an optical semiconductor element according to the present embodiment is attached to a self-luminous display device, one factor that reduces the visibility of images is the reflection of light at the interface between the air and the antiglare layer. The AR layer reduces the surface reflection. Each of the antiglare layer and the antireflection layer may have a multi-layer structure in which two or more layers are laminated.

In addition, in order to prevent the adhesion of contaminants and improve the ease of removing adhered contaminants, a contamination prevention layer made of a fluorine group-containing silane compound or a fluorine group-containing organic compound is laminated on the anti-glare layer. preferably.

In this embodiment, it is preferable to surface-treat at least one of the substrate and the antiglare layer. If the surface of the substrate is surface-treated, the adhesion with the anti-glare layer is further improved. Moreover, if the surface of the anti-glare layer is treated, the adhesion to the AR layer is further improved.

In order to prevent curling of the substrate, the other side of the antiglare layer may be subjected to a solvent treatment. A transparent resin layer may be formed on the other side of the antiglare layer to prevent curling.

<Production of optical semiconductor element encapsulation sheet>
The optical semiconductor element encapsulating sheet can be prepared by laminating a diffusion layer and an antireflection layer. Specifically, it can be carried out by forming a sheet-like diffusion layer and an antireflection layer, respectively, and then laminating them together.

The diffusion layer and the antireflection layer are formed by applying a composition (ionizing radiation-curable resin composition, pressure-sensitive adhesive composition) for forming a resin layer in a sheet (layer) form on a release film. It can be obtained by curing the film by heating and/or irradiating it with ultraviolet rays.

When performing photocuring, a release film is further attached to the surface of the coating film, and the photocurable pressure-sensitive adhesive composition is sandwiched between the two release films and irradiated with ultraviolet rays to prevent polymerization inhibition due to oxygen. Prevention is preferred. Before photocuring, the sheet-like coating film may be heated for the purpose of removing the solvent or dispersion medium. If the solvent or the like is removed by heating, it is preferably carried out before attaching the release film.

Films made of various resin materials are used as the film substrate of the release film. Examples of resin materials include polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate, acetate-based resins, polyethersulfone-based resins, polycarbonate-based resins, polyamide-based resins, polyimide-based resins, polyolefin-based resins, (meth)acrylic-based resins, Polyvinyl chloride-based resins, polyvinylidene chloride-based resins, polystyrene-based resins, polyvinyl alcohol-based resins, polyarylate-based resins, polyphenylene sulfide-based resins, and the like are included. Among these, polyester resins such as polyethylene terephthalate are particularly preferred. The thickness of the film substrate is preferably 10-200 μm, more preferably 25-150 μm. Materials for the release layer include silicone-based release agents, fluorine-based release agents, long-chain alkyl-based release agents, fatty acid amide-based release agents, and the like. The thickness of the release layer is generally about 10 to 2000 nm.

Methods for applying the composition onto the release film include roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, and lip coating. Various methods such as coating and die coating are used.

By irradiating the composition coated in layers on the release film with ultraviolet rays, active species are generated from the photopolymerization initiator, the photopolymerizable compound is polymerized, and the polymerization rate increases (reduces unreacted monomers). Accordingly, the liquid composition becomes a solid (regular) resin layer. The light source for ultraviolet irradiation is not particularly limited as long as it can irradiate light in the wavelength range to which the photopolymerization initiator contained in the composition is sensitive. A metal halide lamp, a xenon lamp, or the like is used.

The integrated light quantity of the irradiation light is, for example, about 100 to 5000 mJ/cm ² . The polymerization rate (non-volatile content) of the pressure-sensitive adhesive layer made of the photocured product of the composition is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. The polymerization rate may be 93% or more or 95% or more. In order to reduce the non-volatile content, the pressure-sensitive adhesive layer may be heated to remove volatile content such as residual monomers, unreacted polymerization initiators and solvents.

The heating temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and particularly preferably 70°C to 170°C. Appropriate time can be adopted as the heating time. The heating time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, particularly preferably 10 seconds to 10 minutes.

When release films are provided on both sides of the pressure-sensitive adhesive layer, the thickness of one release film and the thickness of the other release film may be the same or different. The peeling force when peeling the release film temporarily attached to one surface from the resin layer and the peeling force when peeling the release film temporarily attached to the other surface from the resin layer may be the same or different. good. If the two have different peeling strengths, peel off the peeling film with the relatively smaller peeling strength (light peeling film) first, and then attach the exposed diffusion layer and the antireflection layer to form the diffusion layer. and the antireflection layer are adjacent to each other, and a directly laminated sheet for encapsulating an optical semiconductor element can be produced.

When the sheet for optical semiconductor element encapsulation of the present invention has a form in which the diffusion layer and the antireflection layer are laminated via a base material, the release film (light release film) having a relatively small release force is first peeled off. Then, the exposed diffusion layer and the antireflection layer are attached to the front surface and the back surface of the base material, respectively, thereby obtaining a sheet for optical semiconductor element encapsulation in which the diffusion layer and the antireflection layer are laminated via the base material. can be made.

In the sheet for optical semiconductor element encapsulation of the present invention, it is preferable that the diffusion layer and the antireflection layer are adjacent to each other. That is, the diffusion layer and the antireflection layer are preferably adjacent and directly laminated. This configuration is preferred for reducing color cast in mini/micro LED displays. That is, when the diffusion layer and the antireflection layer are laminated via another layer structure, it becomes difficult to control the reflection and diffusion of the light emitted from the optical semiconductor element of the mini/micro LED display device. It tends to be difficult to prevent color cast.

The shear storage modulus G′25° C. of the diffusion layer and the antireflection layer at a temperature of 25° C. is, for example, about 10 to 1000 kPa, and may be 30 kPa or more, 50 kPa or more, 70 kPa or more, or 100 kPa or more, 700 kPa or less, 500 kPa or more. Below, it may be 300 kPa or less or 200 kPa or less. The shear storage modulus G′85° C. of the diffusion layer and the antireflection layer at a temperature of 85° C. is, for example, about 3 to 300 kPa, and may be 5 kPa or more, 7 kPa or more, or 10 kPa or more, and 200 kPa or less and 150 kPa or less. , or 100 kPa or less. If the shear storage modulus is within the above range, both moderate flexibility and adhesiveness can be achieved. The shear storage modulus is a value measured by dynamic viscoelasticity measurement at a frequency of 1 Hz.

The sheet for optical semiconductor element encapsulation of the present invention may have a release film provided on the diffusion layer and/or the antireflection layer until use. Moreover, when the sheet|seat for optical-semiconductor element encapsulation of this invention has a base material, the surface protection film may be laminated|stacked on the base material. The surface protection film is suitable for preventing the adhesion of scratches and stains during the production, transportation and shipment of the sheet for encapsulating optical semiconductor elements and optical products containing the same.

<Optical semiconductor device, self-luminous display device, image display device>
The optical semiconductor device of the present invention comprises a substrate, one or more optical semiconductor elements arranged on the substrate, and the optical semiconductor element encapsulating sheet of the present invention, wherein the optical semiconductor element encapsulating sheet is , and seals the optical semiconductor element. The optical semiconductor device of the present invention is preferably a self-luminous display device. The image display device of the present invention preferably includes the self-luminous display device of the present invention.

The optical semiconductor device (self-luminous display device) of the present invention comprises a large number of minute optical semiconductor elements arranged on a wiring substrate, and each optical semiconductor element being selectively caused to emit light by a light emission control means connected thereto. Therefore, visual information such as characters, images, moving images, etc. can be directly displayed on the display screen by blinking of each optical semiconductor element. Examples of self-luminous display devices include mini/micro LED display devices and organic EL (electroluminescence) display devices. The sheet for optical semiconductor element encapsulation of the present invention is particularly suitable for use in the production of mini/micro LED display devices.

3 and 4 are schematic diagrams (cross-sectional views) showing an embodiment of the self-luminous display device (mini/micro LED display device) of the present invention.
In FIG. 3, a self-luminous display device (mini/micro LED display device) 20 includes a display panel in which a plurality of LED chips 5 are arranged on one side of a substrate 3, and the optical semiconductor element encapsulation sheet 10 of the present invention. . The LED chip 5 on the substrate 3 is sealed with the antireflection layer 2 of the optical semiconductor element sealing sheet 10 . In FIG. 4, a self-luminous display device (mini/micro LED display device) 21 includes a display panel in which a plurality of LED chips 5 are arranged on one side of a substrate 3, and the optical semiconductor element sealing sheet 10 of the present invention. . The LED chip 5 on the substrate 3 is sealed with the diffusion layer 1 of the optical semiconductor element sealing sheet 10 .

In this embodiment, a metal wiring layer 4 for sending light emission control signals to each LED chip 5 is laminated on the substrate 3 of the display panel. LED chips 5 that emit red (R), green (G), and blue (B) lights are alternately arranged on a substrate 3 of the display panel via metal wiring layers 4 . The metal wiring layer 4 is made of a metal such as copper, reflects external light, and reduces the visibility of the image. In addition, the light emitted from each LED chip 5 of each color of RGB is mixed, and the contrast is lowered.

In the mini/micro LED display device 20 of FIG. 3, the antireflection layer 2 seals between the LED chips 5 arranged on the display panel and the metal wiring layer 4 . The anti-reflection layer 2, which has a higher light-shielding property (lower transparency) than the diffusion layer 1, seals the gaps between the LED chips 5, thereby preventing color mixture between the LED chips 5 and improving the contrast. be able to. In addition, since the antireflection layer 2, which has a higher light-shielding property (lower transparency) than the diffusion layer 1, also seals the surface of the metal wiring layer 4, reflection by the metal wiring layer 4 can be prevented.

In FIG. 3, the diffusion layer 1 seals the upper portion (display image side) of each LED chip 5 arranged on the display panel. The haze value of the diffusion layer 1 is higher than that of the antireflection layer 2, so that the diffusion layer 1 has sufficient light diffusion performance. Since the diffusion layer 1, which has a higher haze value than the antireflection layer 2, seals the upper portion (display image side) of each LED chip 5, the visible light emitted from each LED chip 5 is sufficiently diffused, resulting in a color display. Cast can be effectively reduced.

In the mini/micro LED display device 21 of FIG. 4, the diffusion layer 1 seals between the LED chips 5 arranged on the display panel and the metal wiring layer 4 . Since the diffusion layer 1, which has a higher haze value than the antireflection layer 2, seals the gaps between the LED chips 5, the strong light emitted from the side surfaces of the LED chips 5 is efficiently diffused and made uniform. and effectively reduce color cast.

In FIG. 4, the antireflection layer 2 seals the upper portion (display image side) of each LED chip 5 arranged on the display panel. Since the total light transmittance of the antireflection layer 2 is lower than that of the diffusion layer 1, it has sufficient light shielding performance. Since the antireflection layer 2, which has a lower total light transmittance than the diffusion layer 1, seals the upper portion (on the display image side) of each LED chip 5, the external light reflected on the metal wiring layer 4 is sufficiently blocked. be able to.

As described above, the sheet for encapsulating an optical semiconductor element of the present invention includes an antireflection layer with a higher light-shielding property (lower transparency), and therefore can prevent reflection and gloss on the metal surface. When a metal adherend is laminated on the sheet for optical semiconductor element encapsulation of the present invention, the reflectance in the entire light area may be, for example, 10% or less, but is preferably 8.5% or less. It is preferably 8% or less, more preferably 7.5% or less, and particularly preferably 7% or less. As the metal adherend, copper, aluminum, stainless steel, or the like can be used.

The image display device of the present embodiment may include an optical member other than the self-luminous display device and the optical semiconductor element sealing sheet. Examples of the optical member include, but are not particularly limited to, a polarizing plate, a retardation plate, an antireflection film, a viewing angle adjusting film, and an optical compensation film. The optical member also includes members (design film, decorative film, surface protective plate, etc.) that play a role of decoration and protection while maintaining the visibility of the display device and the input device.

The mini/micro LED display device of the present embodiment is manufactured by bonding a display panel having a plurality of LED chips arranged on one side of a substrate and a diffusion layer or an antireflection layer of the optical semiconductor element encapsulation sheet of the present invention. can do.

Specifically, the display panel and the optical semiconductor element encapsulating sheet can be attached by stacking them under heat and/or pressure. When the display panel and the sheet for optical semiconductor element encapsulation are attached, they can be laminated under heat and/or pressure and then photocured. Photocuring can be performed in the same manner as the photocuring for forming the diffusion layer and/or the antireflection layer described above.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. Various properties in the production examples below were evaluated or measured by the following methods.

(Haze)
The haze value was measured using a haze meter (manufactured by Murakami Color Science Laboratory, trade name "HN-150") according to the method defined in JIS 7136.

(Total light transmittance)
The total light transmittance was measured using a haze meter (manufactured by Murakami Color Science Laboratory, trade name "HN-150") according to the method defined in JIS 7361.

Production example 1
(Preparation of prepolymer)
In a separable flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas inlet tube, 67 parts by weight of butyl acrylate (BA) and 14 parts of cyclohexyl acrylate (CHA, manufactured by Osaka Organic Chemical Industry, trade name "Viscoat #155") were added. parts by weight, 19 parts by weight of 4-hydroxybutyl acrylate (4-HBA), 0.09 parts by weight of a photopolymerization initiator (manufactured by IGM, trade name "Omnilad 184"), and a photopolymerization initiator (manufactured by IGM, product After 0.09 parts by weight of "Omnilad 651") was added, nitrogen gas was supplied and nitrogen substitution was performed for about 1 hour while stirring. Thereafter, UVA was irradiated at 5 mW/cm ² to carry out polymerization, and the reaction rate was adjusted to 5 to 15% to obtain an acrylic prepolymer solution.

Production example 2
(Preparation of black adhesive composition)
9 parts by weight of 2-hydroxyethyl acrylate (HEA) and 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA) were added to the acrylic prepolymer solution obtained in Production Example 1 (the total prepolymer amount being 100 parts by weight). , 0.02 parts by weight of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku, trade name "KAYARAD DPHA") as a polyfunctional monomer, 0.35 parts by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and A photopolymerization initiator (manufactured by IGM, trade name "Omnilad 651") of 0.3 parts was added to prepare a photopolymerizable pressure-sensitive adhesive composition solution.
To 100 parts by weight of the photopolymerizable pressure-sensitive adhesive composition solution obtained above, 0.2 parts of a photopolymerization initiator (manufactured by IGM, trade name "Omnilad 651") and a black pigment dispersion (manufactured by Tokushiki Co., Ltd., 9.2 parts by weight of "TOKUSHIKI 9050 Black" (trade name) was added to prepare a photopolymerizable black adhesive composition solution.

Production example 3
(Preparation of antireflection sheet)
The black adhesive composition solution prepared in Production Example 2 was cured on the release surface of a 38 μm thick release film R1 (Mitsubishi Plastics Co., Ltd., trade name “MRF#38”) in which one side of the polyester film was a release surface. The coating was applied to a thickness of 50 μm afterward, and was covered with a release film R2 (MRE #38, manufactured by Mitsubishi Plastics Co., Ltd.) having a release surface on one side of the polyester film to block air. Ultraviolet rays were irradiated from one side of this laminate using a black light (manufactured by Toshiba Corporation, trade name "FL15BL") under the conditions of an illuminance of 5 mW/cm ² and an integrated light amount of 1300 mJ/cm ² . As a result, an antireflection sheet 1 having a thickness of 50 μm in which the photocrosslinkable adhesive, which is the cured product of the black adhesive composition, is sandwiched between the release films R1 and R2 was obtained in the form of a substrate-less adhesive sheet. .
The illuminance value of the black light is a value measured by an industrial UV checker with a peak sensitivity wavelength of about 350 nm (manufactured by Topcon Corporation, trade name: UVR-T1, light receiving part type UD-T36).
The antireflection sheet 1 had a haze of 22.2% and a total light transmittance of 0.9%.

Production example 4
(Preparation of antireflection sheet)
An antireflection sheet 2 having a thickness of 50 μm was prepared in the same manner as in Production Examples 2 and 3, except that 5.8 parts by weight of a black pigment dispersion (manufactured by Tokushiki Co., Ltd., trade name “Tokushiki 9050 Black”) was added. It was obtained in the form of a substrate-less pressure-sensitive adhesive sheet.
The antireflection sheet 2 had a haze of 16.9% and a total light transmittance of 5.9%.

Production example 5
(Preparation of antireflection sheet)
Antireflection sheet 3 with a thickness of 50 μm was prepared in the same manner as in Production Examples 2 and 3, except that 2.3 parts by weight of a black pigment dispersion (manufactured by Tokushiki Co., Ltd., trade name “Tokushiki 9050 Black”) was added. It was obtained in the form of a substrate-less pressure-sensitive adhesive sheet.
The antireflection sheet 3 had a haze of 8.4% and a total light transmittance of 29.7%.

Production example 6
(Preparation of antireflection sheet)
An antireflection sheet 4 having a thickness of 50 μm was prepared in the same manner as in Production Examples 2 and 3, except that 1.7 parts by weight of a black pigment dispersion (manufactured by Tokushiki Co., Ltd., trade name “Tokushiki 9050 Black”) was added. It was obtained in the form of a substrate-less pressure-sensitive adhesive sheet.
The antireflection sheet 4 had a haze of 7% and a total light transmittance of 38.5%.

Production example 7
(Preparation of antireflection sheet)
Antireflection sheet 5 with a thickness of 50 μm was prepared in the same manner as in Production Examples 2 and 3, except that 3.0 parts by weight of a black pigment dispersion (manufactured by Tokushiki Co., Ltd., trade name “Tokushiki 9256 Black”) was added. It was obtained in the form of a substrate-less pressure-sensitive adhesive sheet.
The antireflection sheet 5 had a haze of 9.1% and a total light transmittance of 20.8%.

Production example 8
(Preparation of adhesive composition)
9 parts by weight of 2-hydroxyethyl acrylate (HEA) and 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA) were added to the acrylic prepolymer solution obtained in Production Example 1 (the total prepolymer amount being 100 parts by weight). , 0.02 parts by weight of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku, trade name "KAYARAD DPHA") as a polyfunctional monomer, 0.35 parts by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and A photopolymerization initiator (manufactured by IGM, trade name "Omnilad 651") of 0.3 parts was added to prepare a photopolymerizable pressure-sensitive adhesive composition solution.
To 100 parts by weight of the photopolymerizable pressure-sensitive adhesive composition solution obtained above, light diffusing fine particles (manufactured by Momentive Performance Materials Japan, trade name "Tospearl 145", silicone resin, refractive index: 1.42 , average particle size: 4.5 μm) was added to prepare a photopolymerizable pressure-sensitive adhesive composition solution.

Production example 9
(Preparation of light diffusion sheet)
The photopolymerizable adhesive composition solution prepared in Production Example 8 was applied to the release surface of a 38 μm-thick release film R1 (manufactured by Mitsubishi Plastics, Inc., trade name “MRF#38”) in which one side of the polyester film was a release surface. was applied so that the thickness after curing was 100 μm, and a release film R2 (manufactured by Mitsubishi Plastics Co., Ltd., MRE #38) having a release surface on one side of the polyester film was covered to block air. Ultraviolet rays were irradiated from one side of this laminate using a black light (manufactured by Toshiba Corporation, trade name "FL15BL") under the conditions of an illuminance of 5 mW/cm ² and an integrated light amount of 1300 mJ/cm ² . As a result, the light diffusion sheet 1 having a thickness of 100 μm in which the photocrosslinkable adhesive, which is the cured product of the photopolymerizable adhesive composition, is sandwiched between the release films R1 and R2 is formed in the form of a substrate-less adhesive sheet. Obtained.
The illuminance value of the black light is a value measured by an industrial UV checker with a peak sensitivity wavelength of about 350 nm (manufactured by Topcon Corporation, trade name: UVR-T1, light receiving part type UD-T36).
The light diffusion sheet 1 had a haze of 38.4% and a total light transmittance of 91.5%.

Production example 10
(Preparation of light diffusion sheet)
Except for adding 2 parts by weight of light diffusing fine particles (manufactured by Momentive Performance Materials Japan, trade name “Tospearl 145”, silicone resin, refractive index: 1.42, average particle size: 4.5 μm) A light diffusion sheet 2 having a thickness of 100 μm was obtained in the form of a substrate-less pressure-sensitive adhesive sheet in the same manner as in Production Examples 8 and 9.
The light diffusion sheet 2 had a haze of 56% and a total light transmittance of 91.3%.

Production Example 11
(Preparation of light diffusion sheet)
Except for adding 5 parts by weight of light diffusing fine particles (manufactured by Momentive Performance Materials Japan, trade name “Tospearl 145”, silicone resin, refractive index: 1.42, average particle size: 4.5 μm) A light diffusion sheet 3 having a thickness of 100 μm was obtained in the form of a substrate-less pressure-sensitive adhesive sheet in the same manner as in Production Examples 8 and 9.
The light diffusion sheet 3 had a haze of 86.6% and a total light transmittance of 91.7%.

Production example 12
(Preparation of light diffusion sheet)
60 parts by weight of light diffusing fine particles (manufactured by Momentive Performance Materials Japan, trade name “Tospearl 145”, silicone resin, refractive index: 1.42, average particle size: 4.5 μm), and 3-phenoxybenzyl A light diffusion sheet 4 with a thickness of 100 μm was prepared in the same manner as in Production Examples 8 and 9, except that 20 parts by weight of acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name “Light Acrylate POB-A”) was added. It was obtained in the form of an adhesive sheet.
The light diffusion sheet 4 had a haze of 99.5% and a total light transmittance of 77%.

Production example 13
(Preparation of light diffusion sheet)
2 parts by weight of light diffusing fine particles (manufactured by Momentive Performance Materials Japan, trade name “Tospearl 145”, silicone resin, refractive index: 1.42, average particle size: 4.5 μm), and 3-phenoxybenzyl A light diffusion sheet 5 with a thickness of 100 μm was prepared in the same manner as in Production Examples 8 and 9, except that 20 parts by weight of acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name “Light Acrylate POB-A”) was added. It was obtained in the form of an adhesive sheet.
The light diffusion sheet 5 had a haze of 58.8% and a total light transmittance of 90.5%.

Production example 14
(Preparation of light diffusion sheet)
Light diffusing fine particles (manufactured by Dupont, trade name “Ti-Pure R706”, titanium oxide, refractive index: about 2.5, average particle size: 0.36 μm) except for adding 0.2 parts by weight In the same manner as in Examples 8 and 9, a light diffusion sheet 6 having a thickness of 100 μm was obtained in the form of a substrate-less pressure-sensitive adhesive sheet.
The light diffusion sheet 6 had a haze of 44.8% and a total light transmittance of 78.4%.

Production example 15
(Preparation of light diffusion sheet)
9 parts by weight of 2-hydroxyethyl acrylate (HEA) and 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA) were added to the acrylic prepolymer solution obtained in Production Example 1 (the total prepolymer amount being 100 parts by weight). , 0.02 parts by weight of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku, trade name "KAYARAD DPHA") as a polyfunctional monomer, 0.35 parts by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and A photopolymerization initiator (manufactured by IGM, trade name "Omnilad 651") of 0.3 parts was added to prepare a photopolymerizable pressure-sensitive adhesive composition solution.
7.18 parts by weight of 4-hydroxybutyl acrylate (4-HBA) and 21.53 parts by weight of 2-ethylhexyl acrylate (2-EHA) were added to 41.3 parts by weight of the photopolymerizable adhesive composition solution obtained above. , Dipentaerythritol hexaacrylate (DPHA) 0.01 parts by weight, photopolymerization initiator (manufactured by IGM, trade name "Omnilad 651") 0.092 parts by weight, and light diffusing fine particles (Momentive Performance Materials, Japan Co., Ltd., trade name "Tospearl 145", silicone resin, refractive index: 1.42, average particle size: 4.5 µm) was added to prepare a photopolymerizable pressure-sensitive adhesive composition solution.
Using the photopolymerizable adhesive composition solution obtained above, in the same manner as in Production Example 9, a light diffusion sheet 7 having a thickness of 50 μm sandwiched between release films R1 and R2 was prepared as a substrate-less adhesive sheet. obtained in the form The light diffusion sheet 7 had a haze of 96.3% and a total light transmittance of 91.8%.

Production example 16
(Preparation of light diffusion sheet)
9 parts by weight of 2-hydroxyethyl acrylate (HEA) and 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA) were added to the acrylic prepolymer solution obtained in Production Example 1 (the total prepolymer amount being 100 parts by weight). , 0.02 parts by weight of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku, trade name "KAYARAD DPHA") as a polyfunctional monomer, 0.35 parts by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and A photopolymerization initiator (manufactured by IGM, trade name "Omnilad 651") of 0.3 parts was added to prepare a photopolymerizable pressure-sensitive adhesive composition solution.
23 parts by weight of benzyl acrylate (BZA, Viscoat #160, Osaka Organic Chemical Industry Co., Ltd.) and 15.7 parts by weight of butyl acrylate (BA) were added to 38.2 parts by weight of the photopolymerizable adhesive composition solution obtained above. , Dipentaerythritol hexaacrylate (DPHA) 0.02 parts by weight, photopolymerization initiator (manufactured by IGM, trade name "Omnilad 651") 0.092 parts by weight, and light diffusing fine particles (Momentive Performance Materials, Japan Co., Ltd., trade name "Tospearl 145", silicone resin, refractive index: 1.42, average particle size: 4.5 µm) was added to prepare a photopolymerizable pressure-sensitive adhesive composition solution.
Using the photopolymerizable adhesive composition solution obtained above, in the same manner as in Production Example 9, a light diffusion sheet 8 having a thickness of 50 μm sandwiched between release films R1 and R2 was prepared as a substrate-less adhesive sheet. obtained in the form The light diffusion sheet 8 had a haze of 98.0% and a total light transmittance of 89.5%.

Production Example 17
(Preparation of adhesive sheet)
Adhesive sheet 1 having a thickness of 50 μm was prepared as a substrate-less adhesive sheet in the same manner as in Production Examples 8 and 9, except that the light diffusing fine particles were not added and the thickness after curing was 50 μm. obtained in the form
The adhesive sheet 1 had a haze of 0.6% and a total light transmittance of 92.4%.

Production example 18
(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet 2 having a thickness of 100 μm was obtained in the form of a substrate-less pressure-sensitive adhesive sheet in the same manner as in Production Examples 8 and 9, except that the light-diffusing fine particles were not added.
The adhesive sheet 2 had a haze of 0.6% and a total light transmittance of 92.4%.

Example 1
(Preparation of sheet for optical semiconductor element encapsulation)
One release film was peeled off from the antireflection sheet 2 obtained in Production Example 4 cut into a size of 50 mm×45 mm to expose the adhesive surface. The adhesive surface exposed by peeling one of the release films from the light diffusion sheet 1 obtained in Production Example 9 cut to 50 mm × 45 mm is attached to the adhesive surface of the antireflection sheet 2, whereby the release film 1 is obtained. A laminate 1 was obtained as a sheet for optical semiconductor element encapsulation consisting of /antireflection sheet 2/light diffusion sheet 1/release film 2.

Examples 2-14, Comparative Examples 1-4
(Preparation of sheet for optical semiconductor element encapsulation)
Laminates 2 to 18 were obtained in the same manner as in Example 1, except that the laminate structures shown in Tables 1 and 2 were used.

(evaluation)
The following evaluations were performed using the sheets for optical semiconductor element encapsulation obtained in the above Examples and Comparative Examples. The evaluation method is shown below.

(1) Haze The release film 2 of the sheet for optical semiconductor element encapsulation obtained in Examples and Comparative Examples was peeled off and attached to a glass plate. Next, peel off the release film 1, set it in a haze meter (manufactured by Murakami Color Science Laboratory, trade name "HN-150") so that light enters from the exposed adhesive surface, and set it according to JIS 7136. The haze value was measured by Tables 1 and 2 show the results.

(2) Total Light Transmittance The release film 2 of the optical semiconductor element encapsulation sheet obtained in Examples and Comparative Examples was peeled off and attached to a glass plate. Next, peel off the release film 1, set it in a haze meter (manufactured by Murakami Color Science Laboratory, trade name "HN-150") so that light enters from the exposed adhesive surface, and set it according to JIS 7361. was used to measure the total light transmittance. Tables 1 and 2 show the results.

(3) Reflectance The adhesive surface exposed by peeling the release film 2 of the optical semiconductor element encapsulation sheet obtained in the above Examples and Comparative Examples was bonded to an aluminum foil. The resulting sample was placed on Solidspec 3700 (manufactured by Shimadzu Corporation) with release film 1 on the light source side, and the reflectance (%) of 280 to 780 nm was measured. Tables 1 and 2 show the reflectance at 550 nm. The antireflection function was evaluated according to the following criteria. Tables 1 and 2 show the results.
○: Reflectance at 550 nm is 8.5% or less △: Reflectance at 550 nm is more than 8.5% and 10% or less ×: Reflectance at 550 nm is more than 10%

(4) Light Diffusion Effect The release film 2 of the sheet for encapsulating optical semiconductor elements obtained in Examples and Comparative Examples was peeled off and attached to a glass plate.
An LED lamp (manufactured by EK Japan Co., Ltd., trade name “LK-3PG”) was installed on the upper part of the screen so as to have a height of 2.4 cm. The glass plate side of the obtained sample was brought into close contact with the LED lamp. Connect a battery box (manufactured by EK Japan Co., Ltd., product name "AP-180") to the LED lamp, turn on the LED lamp, measure the diameter of the circular image projected on the screen, and measure the light diffusion effect according to the following criteria. evaluated. Tables 1 and 2 show the results.

〇: Diameter exceeds 2 cm ×: Diameter is 2 cm or less

* In Table 2, Comparative Example 1 uses Adhesive Sheet 1 as an antireflection layer, Comparative Example 2 uses Adhesive Sheet 2 as a diffusion layer, Comparative Example 3 uses Adhesive Sheet 1 as an antireflection layer, Adhesive Sheet 2 as a diffusion layer, and Comparative Example 4. shows T ₁ , T ₂ , H ₁ , and H ₂ using the adhesive sheet 2 as a diffusion layer.

Variations of the present invention are appended below.
[Appendix 1] A sheet for sealing one or more optical semiconductor elements arranged on a substrate,
The sheet comprises a diffusion layer and an antireflection layer,
The total light transmittance T ₁ of the diffusion layer and the total light transmittance T ₂ of the antireflection layer satisfy T ₁ >T ₂ ,
A sheet for encapsulating an optical semiconductor element, wherein a haze value H ₁ of the diffusion layer and a haze value H ₂ of the antireflection layer satisfy H ₁ >H ₂ .
[Appendix 2] The sheet for optical semiconductor element encapsulation according to Appendix 1, wherein the diffusion layer has a haze value H ₁ of 30 to 99.9%.
[Appendix 3] The sheet for optical semiconductor element encapsulation according to Appendix 1 or 2, wherein the antireflection layer has a total light transmittance T ₂ of 1 to 30%.
[Appendix 4] The sheet for optical semiconductor element encapsulation according to any one of Appendices 1 to 3, wherein the diffusion layer and the antireflection layer are adjacent to each other.
[Appendix 5] The sheet for optical semiconductor element encapsulation according to any one of Appendices 1 to 4, wherein the diffusion layer is a resin layer, and the antireflection layer is a resin layer.
[Appendix 6] The sheet for optical semiconductor element encapsulation according to any one of Appendices 1 to 4, wherein the diffusion layer is an adhesive layer, and the antireflection layer is an adhesive layer.
[Appendix 7] A substrate, one or more optical semiconductor elements arranged on the substrate, and the optical semiconductor element sealing sheet according to any one of Appendixes 1 to 6,
An optical semiconductor device, wherein the sheet for optical semiconductor element encapsulation seals the optical semiconductor element.
[Appendix 8] The optical semiconductor device according to Appendix 7, which is a self-luminous display device.
[Appendix 9] An image display device comprising the self-luminous display device according to Appendix 8.

The sheet for encapsulating optical semiconductor elements of the present invention is suitable for encapsulating optical semiconductor elements of self-luminous display devices such as mini/micro LEDs.

10, 11 Optical semiconductor element sealing sheet 1 Diffusion layer 2 Antireflection layer S Base material 20, 21 Self-luminous display device (mini/micro LED display device)
3 substrate 4 metal wiring layer 5 optical semiconductor device (LED chip)

Claims (10)

A sheet for sealing one or more optical semiconductor elements arranged on a substrate,
The sheet comprises a diffusion layer and an antireflection layer,
The total light transmittance T ₁ of the diffusion layer and the total light transmittance T ₂ of the antireflection layer satisfy T ₁ >T ₂ ,
A sheet for encapsulating an optical semiconductor element, wherein a haze value H ₁ of the diffusion layer and a haze value H ₂ of the antireflection layer satisfy H ₁ >H ₂ . 2. The sheet for optical semiconductor element encapsulation according to claim 1, wherein the diffusion layer has a haze value H ₁ of 30 to 99.9%. 2. The sheet for optical semiconductor element encapsulation according to claim 1, wherein the antireflection layer has a total light transmittance T ₂ of 1 to 30%. 3. The sheet for optical semiconductor element encapsulation according to claim 2, wherein the antireflection layer has a total light transmittance T ₂ of 1 to 30%. The sheet for optical semiconductor element encapsulation according to any one of claims 1 to 4, wherein the diffusion layer and the antireflection layer are adjacent to each other. The sheet for encapsulating an optical semiconductor element according to any one of claims 1 to 4, wherein the diffusion layer is a resin layer, and the antireflection layer is a resin layer. The optical semiconductor element encapsulating sheet according to any one of claims 1 to 4, wherein the diffusion layer is an adhesive layer, and the antireflection layer is an adhesive layer. A substrate, one or more optical semiconductor elements arranged on the substrate, and the sheet for encapsulating an optical semiconductor element according to any one of claims 1 to 4,
An optical semiconductor device, wherein the sheet for optical semiconductor element encapsulation seals the optical semiconductor element. 9. The optical semiconductor device according to claim 8, which is a self-luminous display device. An image display device comprising the self-luminous display device according to claim 9 .

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