JP7369761B2 - Sheet for encapsulating optical semiconductor devices - Google Patents

Description

The present invention relates to a sheet for encapsulating optical semiconductor devices. More specifically, the present invention relates to a sheet suitable for sealing 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. The basic configuration of mini/micro LED display devices is to use a substrate on which many minute optical semiconductor elements (LED chips) are arranged at high density as a display panel, and the optical semiconductor elements are sealed with a sealing material. , a cover member such as a resin film or a glass plate is laminated on the outermost layer.

BACKGROUND ART Displays using self-luminous display devices such as backlights have a problem in that uneven brightness (luminance unevenness) occurs due to the light source of the optical semiconductor element. Patent Document 1 discloses, as an adhesive sheet capable of suppressing brightness unevenness, a composite adhesive layer comprising a light-diffusing adhesive layer containing light-diffusing fine particles and a transparent adhesive layer not containing light-diffusing fine particles. A pressure-sensitive adhesive sheet is disclosed, in which at least one of the light-diffusing pressure-sensitive adhesive layer and the transparent pressure-sensitive adhesive layer is made of an active energy ray-curable pressure-sensitive adhesive.

JP 2021-38365 Publication

However, while the adhesive sheet disclosed in Patent Document 1 exhibits a light-diffusing function due to the light-diffusing adhesive layer, the light incident on the adhesive sheet is reflected within the light-diffusing adhesive layer and is confined within the layer. It is difficult for light to be emitted from the adhesive sheet, and the light extraction efficiency of the adhesive sheet is low. For this reason, there has been a problem in that the brightness is insufficient when the pressure-sensitive adhesive sheet is used for sealing optical semiconductor devices.

The present invention was devised under these circumstances, and its purpose is to provide a sheet for encapsulating optical semiconductor elements that has excellent light diffusivity and light extraction efficiency. .

As a result of intensive studies to achieve the above object, the present inventors found that the difference in L ^* (SCE) measured from both sides of a sheet for encapsulating an optical semiconductor element having a light diffusion layer in a state in which functional layers are laminated; It has been found that an optical semiconductor element sealing sheet in which the difference in a ^* (SCE) and the difference in b ^* (SCE) are smaller than ±5 has excellent light diffusivity and light extraction efficiency. The present invention was completed based on these findings.

That is, the present invention is a sheet for sealing one or more optical semiconductor elements arranged on a substrate,
The sheet includes a sealing portion including a light diffusion layer and an antireflection layer,
With a functional layer laminated on one side ^{of the} sheet, L ^* (SCE), ^{a *} ( SCE), b ^* (SCE) are L ^* ₁ , a ^* ₁ , b ^* _1, respectively, and L ^* a ^* b ^* (SCE) when measured under the conditions of 10° field of view from the sheet side and light source D65. When L ^* (SCE), a ^* (SCE), b ^* (SCE) are respectively L ^* ₂ , a ^* ₂ , b ^* ₂ , the above L ^* ₁ , a ^* ₁ , b ^* ₁ , L ^* ₂ , a ^* ₂ , and b ^* ₂ each have values satisfying the following formulas (1) to (3).
-5<L ^* ₁ -L ^* ₂ <5 (1)
-5<a ^* ₁ -a ^* ₂ <5 (2)
-5<b ^* ₁ -b ^* ₂ <5 (3)

The above-mentioned sheet for encapsulating an optical semiconductor element has excellent light diffusing properties because the encapsulating portion includes a light diffusing layer. Further, since the sealing portion includes an antireflection layer, reflection of light by the metal wiring and the like is suppressed, for example, when the light is turned off, and the screen has a good appearance and is excellent in design. Moreover, the above-mentioned optical semiconductor element sealing sheet is often used with functional layers laminated thereon. Therefore, in the sheet for encapsulating optical semiconductor devices in which functional layers are laminated, the above L ^* ₁ , a ^* ₁ , b ^* ₁ , L ^* ₂ , a ^* ₂ , and b ^* ₂ satisfy the above formulas (1) to 1, respectively. ^{The optical semiconductor} Since the brightness and color tone of the light emitted by the device and the light that the viewer sees through the optical semiconductor element sealing sheet are approximately the same, the light extraction efficiency and light diffusivity of the optical semiconductor element sealing sheet are good. becomes.

The sheet for encapsulating an optical semiconductor element preferably has a total light transmittance of 2 to 30% when measured from the functional layer side with the functional layer laminated on one side. When the total light transmittance is 2% or more, the light extraction efficiency is excellent and the brightness of the optical semiconductor device can be further ensured. When the total light transmittance is 30% or less, the antireflection function and contrast of metal wiring in an optical semiconductor device can be further improved.

It is preferable that the sealing part has, in this order, the light diffusion layer, the antireflection layer, and the light diffusion layer or a colorless transparent layer that is not intended to exhibit a light diffusion function. By having such a configuration, it is possible to further reduce the difference in L ^* (SCE), the difference in a ^* (SCE), and the difference in b ^* (SCE) measured from both sides, and the brightness of the optical semiconductor device can be reduced. can be made higher.

The light diffusing layer preferably contains a light diffusing agent having a refractive index of 1.4 to 1.7. By having such a configuration, it is possible to further reduce the difference in L ^* (SCE), the difference in a ^* (SCE), and the difference in b ^* (SCE) measured from both sides, and the brightness of the optical semiconductor device can be reduced. can be made higher. Further, the sheet for encapsulating an optical semiconductor element also has excellent light diffusing properties.

It is preferable that the light diffusing agent is made of silicone resin. By having such a configuration, the light extraction efficiency of the light diffusion layer can be made higher, and the brightness of the optical semiconductor device can be made higher. Further, the sheet for encapsulating an optical semiconductor element also has excellent light diffusing properties.

Preferably, the functional layer includes a surface treatment layer. By having such a configuration, the sheet for encapsulating an optical semiconductor element in which a functional layer including a surface treatment layer is laminated has excellent light diffusivity and light extraction efficiency.

The present invention also provides an optical semiconductor device comprising a substrate, an optical semiconductor element disposed on the substrate, and the optical semiconductor element sealing sheet that seals the optical semiconductor element with the sealing portion. provide. Such an optical semiconductor device has excellent design, high brightness, and is less likely to have uneven brightness.

Preferably, the optical semiconductor device is a self-luminous display device.

Further, the present invention provides an image display device including the self-luminous display device.

The sheet for encapsulating an optical semiconductor element of the present invention has excellent light diffusivity and light extraction efficiency. Therefore, according to the sheet for encapsulating an optical semiconductor element of the present invention, in a state in which an optical semiconductor element is sealed, the sheet has excellent design, high brightness, and less uneven brightness. By using the optical semiconductor element sealing sheet of the present invention, the appearance of the optical semiconductor element is good when the optical semiconductor element is not lit, and the light emitted from the optical semiconductor element is efficiently used when the optical semiconductor element is lit. It is possible to provide an optical semiconductor device that allows light to pass through in a diffused state.

FIG. 1 is a cross-sectional view of a sheet for encapsulating an optical semiconductor device according to an embodiment of the present invention. FIG. 1 is a cross-sectional view of an optical semiconductor device using an optical semiconductor element sealing sheet according to an embodiment of the present invention. 3 is an external view showing an embodiment of an optical semiconductor device manufactured by tiling the optical semiconductor device shown in FIG. 2. FIG. FIG. 2 is a cross-sectional view showing a sealing process in an embodiment of a method for manufacturing an optical semiconductor device. 5 is a cross-sectional view showing a laminate obtained after the sealing step shown in FIG. 4. FIG. FIG. 6 is a cross-sectional view showing dicing positions in the dicing process of the laminate shown in FIG. 5. FIG.

[Sheet for encapsulating optical semiconductor elements]
The optical semiconductor device sealing sheet of the present invention includes at least a sealing portion including a light diffusion layer and an antireflection layer. The light diffusion layer and the antireflection layer are different layers, and the sealing section includes at least two layers: the light diffusion layer and the antireflection layer. Note that in this specification, the optical semiconductor element sealing sheet refers to a sheet for sealing one or more optical semiconductor elements arranged on a substrate with a sealing part. Moreover, in this specification, "sealing an optical semiconductor element" refers to embedding at least a portion of the optical semiconductor element in a sealing part, or following and covering it with the sealing part. The sealing section has flexibility that allows at least a portion of the optical semiconductor element to be embedded or to be followed and covered by the sealing section.

The antireflection layer has a function of suppressing reflection of light emitted by an optical semiconductor element in an optical semiconductor device. By providing the anti-reflection layer, for example, in a display device, reflection of light by metal wiring etc. can be suppressed when the lights are turned off, and the screen can be made to look good and have excellent design. The antireflection layer may be a single layer or a multilayer within the sealing part.

The light diffusion layer exhibits a function of diffusing light. By including the light diffusion layer, uneven brightness can be suppressed in the optical semiconductor device. The light diffusing layer may be a single layer or a multilayer within the sealing part.

The sealing portion may include a layer other than the antireflection layer and the light diffusion layer. Examples of the other layers include a colorless transparent layer (non-light-diffusing layer) that is not intended to exhibit a light-diffusing function.

The sealing section includes at least a first sealing layer that contacts the optical semiconductor element. The sealing section preferably further includes a second sealing layer laminated on the first sealing layer, and more preferably further includes a third sealing layer laminated on the second sealing layer. preferable. In this case, at least one of the first sealing layer, the second sealing layer, and the third sealing layer is the antireflection layer, and at least one other layer is the light diffusion layer. Among the first sealing layer, the second sealing layer, and the third sealing layer, one layer is the light diffusion layer, the other layer is the antireflection layer, and the remaining layer is the light diffusion layer. Or it is preferable that it is the said non-light-diffusion layer. In the sealing part, the stacking positions of the antireflection layer and the light diffusion layer are not particularly limited. In the optical semiconductor element sealing sheet, the first sealing layer, the second sealing layer, the second sealing layer, and the third sealing layer are preferably laminated directly, respectively.

The laminated structure of the first sealing layer, second sealing layer, and third sealing layer [first sealing layer/second sealing layer/third sealing layer] is [light diffusion layer/antireflection layer]. layer/non-light diffusion layer], [non-light diffusion layer/anti-reflection layer/light-diffusion layer], [light-diffusion layer/anti-reflection layer/light-diffusion layer], [non-light-diffusion layer/light-diffusion layer/anti-reflection layer ], [Light diffusion layer/non-light diffusion layer/antireflection layer], [light diffusion layer/light diffusion layer/antireflection layer], [light diffusion layer/antireflection layer/antireflection layer], [antireflection layer/ [Light diffusion layer/Non-light diffusion layer], [Anti-reflection layer/Non-light diffusion layer/Light diffusion layer], [Anti-reflection layer/Light diffusion layer/Light diffusion layer], [Anti-reflection layer/Light diffusion layer/Anti-reflection layer], [antireflection layer/antireflection layer/light diffusion layer], and the like.

Among these, it is preferable that the second sealing layer and/or the third sealing layer is an antireflection layer, and it is more preferable that the second sealing layer is an antireflection layer. When the second sealing layer is an anti-reflection layer, the third sealing layer may be any of an anti-reflection layer, a light-diffusing layer, and a non-light-diffusing layer; It is preferable that there be. When the third sealing layer is a light diffusion layer or a non-light diffusion layer, it is preferable that the first sealing layer and/or the third sealing layer are light diffusion layers. Among these, it is preferable that one of the first sealing layer and the third sealing layer is a light diffusion layer and the other is a non-light diffusion layer, it is more preferable that the first sealing layer is a light diffusion layer, and the first sealing layer is preferably a light diffusion layer. More preferably, one sealing layer is a light-diffusing layer and the third sealing layer is a non-light-diffusing layer. In these cases, the effect of suppressing uneven brightness and the designability tend to be better.

The laminated structure [first sealing layer/second sealing layer/third sealing layer] includes, among others, [light diffusion layer/antireflection layer/non-light diffusion layer], [non-light diffusion layer/antireflection layer] layer/light diffusion layer], [light diffusion layer/antireflection layer/light diffusion layer], [non-light diffusion layer/light diffusion/antireflection layer], and [light diffusion layer/non-light diffusion layer/antireflection layer]. preferable.

It is particularly preferable that the sealing part has the light diffusion layer, the antireflection layer, and the light diffusion layer or the non-light diffusion layer in this order. With such a configuration, the difference in L ^* (SCE), the difference in a ^* (SCE), and the difference in b ^* (SCE) measured from both sides can be made smaller, and the brightness of the optical semiconductor device can be reduced. Can be higher. Such a laminated structure [first sealing layer/second sealing layer/third sealing layer] includes [light diffusion layer/antireflection layer/non-light diffusion layer], [non-light diffusion layer/antireflection layer] layer/light diffusion layer] and [light diffusion layer/antireflection layer/light diffusion layer].

The first sealing layer, the second sealing layer, and the third sealing layer may each independently be a resin layer having a property of being cured by radiation irradiation (radiation curable resin layer), It may also be a resin layer that does not have the property of being cured by radiation (radiation non-curable resin layer). Examples of the radiation include electron beams, ultraviolet rays, α rays, β rays, γ rays, and X rays.

Preferably, the first sealing layer is a radiation non-curable resin layer. With such a configuration, the first sealing layer located on the surface of the optical semiconductor element sealing sheet has excellent adhesion to the optical semiconductor element and the substrate when the optical semiconductor element is sealed, and the optical semiconductor element Excellent followability and embeddability. As a result, the design is excellent even when the height difference due to the optical semiconductor element is high.

The second sealing layer and/or the third sealing layer are preferably radiation-curable resin layers. With such a configuration, after the optical semiconductor element is sealed, the second sealing layer and/or the third sealing layer are cured by radiation irradiation, and the adhesion of the side surface of the optical semiconductor element sealing sheet is improved. descend. As a result, the adhesion between the sheets of adjacent optical semiconductor devices in the tiling state is low, and when adjacent optical semiconductor devices are separated from each other, sheet loss and adhesion of sheets of adjacent optical semiconductor devices are less likely to occur.

The first sealing layer is a layer that comes into contact with the optical semiconductor element when sealing the optical semiconductor element (that is, the side of the substrate provided with the optical semiconductor element). The first sealing layer may or may not have adhesiveness and/or adhesiveness. Among these, the first sealing layer may have adhesiveness and/or adhesiveness in order to be able to adhere to the substrate and the optical semiconductor element with sufficient adhesion force and sufficiently seal the optical semiconductor element. preferable.

The second sealing layer may or may not have adhesiveness and/or adhesiveness. Among these, it is preferable to have adhesiveness and/or adhesiveness. By having such a configuration, when sealing the optical semiconductor element, the optical semiconductor element can be easily sealed, and the adhesion with the first sealing layer located on the surface on the optical semiconductor element side can be improved. It has excellent sealing properties for optical semiconductor devices.

The third sealant may or may not have adhesive and/or adhesive properties. Among these, it is preferable to have adhesiveness and/or adhesiveness. With such a configuration, the third sealing layer has excellent followability of the interface in a state where it is laminated with other members such as the base material part. For this reason, when an optical semiconductor element is sealed with the optical semiconductor element sealing sheet, it is difficult to form a gap between the third sealing layer and other members to which the third sealing layer is in close contact or adhered, and the light diffusivity and light extraction efficiency are improved. Excellent. Further, when sealing the optical semiconductor element, the optical semiconductor element can be easily sealed, and furthermore, the adhesiveness with the second sealing layer is excellent, and the sealing performance of the optical semiconductor element is more excellent.

The sheet for encapsulating an optical semiconductor element of the present invention may be provided on at least one surface of the base material portion, or may be formed on the release-treated surface of the release liner. When the base material portion is not provided, both surfaces of the sheet for encapsulating an optical semiconductor device may be in contact with a release liner. The release liner is used as a protective material for the optical semiconductor element sealing sheet, and is peeled off when sealing the optical semiconductor element. Note that the base material portion and the release liner do not necessarily need to be provided.

Hereinafter, one embodiment of the sheet for encapsulating an optical semiconductor element of the present invention will be described. FIG. 1 is a cross-sectional view showing one embodiment of the optical semiconductor device sealing sheet of the present invention. As shown in FIG. 1, an optical semiconductor element sealing sheet 1 can be used to seal one or more optical semiconductor elements arranged on a substrate, and is a sheet that can be used to seal one or more optical semiconductor elements arranged on a substrate. A sealing part 2 formed on a material part 4 is provided. The base portion 4 is composed of a base film 41 and a functional layer 42 which is a surface treatment layer, but may be composed of the base film 41 without the functional layer 42. The sealing part 2 includes, for example, a first sealing layer 21 that is a light diffusion layer, a second sealing layer 22 that is an antireflection layer, and a third sealing layer 23 that is a light diffusion layer or a non-light diffusion layer. It is formed from a laminate of The second sealing layer 22 is directly laminated on the first sealing layer 21 , and the third sealing layer 23 is directly laminated on the second sealing layer 22 . A release liner 3 is attached to one side of the first sealing layer 21, and a base member 4 is attached to the third sealing layer 23.

The sheet for encapsulating an optical semiconductor device of the present invention has L ^* a ^* b ^* (SCE) when measured with a functional layer laminated on one side under conditions of a 10° field of view from the functional layer side and a light source of D65. L ^* (SCE), a ^* (SCE), and b ^* (SCE) in are L ^* ₁ , a ^* ₁ , and b ^* ₁ respectively, and when measured under the conditions of 10° field of view from the sheet side and light source D65. When L ^* (SCE), a ^{* (} SCE), and b * (SCE) in L ^* a ^* b ^* (SCE) are respectively L ^* ₂ , a ^* ₂ , and b ^* ₂ , the above L ^* ₁ and a ^* ₁ , b ^* ₁ , L ^* ₂ , a ^* ₂ , and b ^* ₂ are values that satisfy the following formulas (1) to (3), respectively.
-5<L ^* ₁ -L ^* ₂ <5 (1)
-5<a ^* ₁ -a ^* ₂ <5 (2)
-5<b ^* ₁ -b ^* ₂ <5 (3)

The above L ^* ₁ , a ^* ₁ , b ^* ₁ , L ^* ₂ , a ^* ₂ , and b ^* ₂ must each satisfy the above formulas (1) to (3), that is, L ^* measured from both sides. (SCE), a ^* (SCE), and b ^* (SCE) are smaller than ±5, so that the light emitted by the optical semiconductor element and the viewer can be connected to each other through the optical semiconductor element sealing sheet. Since the brightness and color tone of the optical semiconductor element sealing sheet are the same as those of the visible light, the light extraction efficiency and light diffusivity of the optical semiconductor element sealing sheet are improved.

L ^* ₁ -L ^* ₂ in the above formula (1) is greater than -5, preferably greater than -3, and more preferably greater than -1. Further, L ^* ₁ -L ^* ₂ is less than 5, preferably less than 4, and more preferably less than 3.

a ^* ₁ -a ^* ₂ in the above formula (2) is greater than -5, preferably greater than -3, and more preferably greater than -1. Further, a ^* ₁ -a ^* ₂ is less than 5, preferably less than 3, more preferably less than 1, and still more preferably less than 0.5.

b ^* ₁ -b ^* ₂ in the above formula (3) is greater than -5, preferably greater than -3, and more preferably greater than -1.5. Further, b ^* ₁ -b ^* ₂ is less than 5, preferably less than 3, more preferably less than 1, and still more preferably less than 0.5.

In addition, L ^* in L ^* a ^* b ^* (SCE) when measured under the condition of 10° field of view from one side and light source D65 in the state where the above functional layer of the above optical semiconductor element sealing sheet is not laminated. (SCE), a ^* (SCE), and b ^* (SCE) are L ^* ₁ , a ^* ₁ , and b ^* ₁ respectively, and L ^* is measured under the conditions of 10° field of view from the other surface and light source D65. When L ^* (SCE), a ^* (SCE), and b ^* (SCE) in a ^* b * (SCE) ^are respectively L ^* ₂ , a ^* ₂ , and b ^* ₂ , the above L ^* ₁ and a ^* ₁ , b ^* ₁ , L ^* ₂ , a ^* ₂ , and b ^* ₂ are preferably values that satisfy the above formulas (1) to (3), respectively.

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

The sheet for encapsulating an optical semiconductor element of the present invention may include the above functional layer. When the above-mentioned functional layer is provided, the above-mentioned L ^* a ^* b ^* (SCE) can be measured without laminating a separate functional layer. In this case, the above-mentioned "sheet side" shall refer to the side not provided with the above-mentioned functional layer. When the sheet for encapsulating an optical semiconductor element of the present invention does not include the above functional layer, a functional layer is separately laminated and the above L ^* a ^* b ^* (SCE) is measured. The functional layer is preferably laminated on the third sealing layer side, which will be described later, with respect to the first sealing layer side, which will be described later.

In the optical semiconductor element sealing sheet 1 shown in FIG. 1, a functional layer 42 is laminated on the surface of the base film 41 in the base portion 4. For example, in the optical semiconductor element sealing sheet 1, L ^* ₁ , a ^* ₁ , and b ^* ₁ are values measured from the functional layer 42 side (upper side in FIG. 1), and L ^* ₂ , a ^* ₂ , and b ^* ₂ are measured from the first sealing layer 21 side (lower side in FIG. 1), which is the side opposite to the side on which the functional layer 4 is laminated, with or without peeling off the release liner 3. is the value.

(Anti-reflection layer)
The antireflection layer preferably contains at least a colorant. The antireflection layer is preferably a resin layer made of resin. The colorant may be 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 low haze even when added in small amounts, and are easy to distribute uniformly without settling unlike pigments. Pigments are also preferred because they provide high color development even when added in small amounts. If a pigment is used as a coloring agent, it is preferably one with low or no electrical conductivity. The above coloring agents may be used alone or in combination of two or more.

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

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

Examples of ultraviolet-transparent black pigments that absorb less ultraviolet light than visible light include the product name "9050BLACK" and the product name "UVBK-0001" (both manufactured by Tokushiki Co., Ltd.). Examples of the ultraviolet-transparent black dye include the trade name "SOC-L-0123" (manufactured by Orient Chemical Industry Co., Ltd.).

Carbon black and titanium black, which are commonly used as black colorants, absorb more ultraviolet light than visible light (their ultraviolet transmittance is lower than their visible light transmittance). Therefore, when a colorant such as carbon black is added to a radiation-curable resin that is sensitive to ultraviolet light, most of the ultraviolet light irradiated for photocuring is absorbed by the colorant, and the amount of light absorbed by the photopolymerization initiator is small. Photocuring takes time (the cumulative amount of irradiation light increases). Furthermore, when the thickness of the layers to be laminated is large, there is a tendency for insufficient photocuring even if light irradiation is performed for a long time because less ultraviolet rays reach the surface opposite to the light irradiation surface. On the other hand, by using a colorant that has a higher transmittance for ultraviolet light than visible light, curing inhibition caused by the colorant can be suppressed.

The content of the colorant in the antireflection layer is 0.01 to 20 parts by mass based on 100 parts by mass of the resin constituting the antireflection layer, from the viewpoint of imparting an appropriate antireflection ability to the sheet for encapsulating semiconductor elements. It is preferably 0.1 to 15 parts by mass, and even more preferably 1 to 10 parts by mass, and may be added as appropriate depending on the type of colorant, the color tone and light transmittance of the sheet for encapsulating semiconductor elements, etc. Just set it. The colorant may be added to the composition as a solution or dispersion dissolved or dispersed in a suitable solvent.

The haze value (initial haze value) of the antireflection layer is not particularly limited, but from the viewpoint of ensuring visibility of the optical semiconductor device, it is preferably 30% or less, more preferably 25% or less, and even more preferably 20% or less. , particularly preferably 15% or less. Further, the haze value of the antireflection layer is preferably 1% or more, more preferably 3% or more, still more preferably 5% or more, particularly preferably 8% or more, from the viewpoint of efficiently reducing brightness unevenness of the optical semiconductor device. % or more, and may be 10% or more. When the antireflection layer is a radiation-curable resin layer, the haze value may be a value before curing or a value after curing.

The total light transmittance of the antireflection layer is not particularly limited, but from the viewpoint of further improving the antireflection function and contrast of metal wiring in optical semiconductor devices, the total light transmittance of the antireflection layer is preferably 30% or less, more preferably 25% or less, More preferably it is 20% or less, particularly preferably 10% or less. Further, the total light transmittance of the antireflection layer is preferably 0.5% or more, more preferably 1% or more, and even more preferably 1.5% from the viewpoint of ensuring the brightness of the optical semiconductor device. Above, it is particularly preferably 2% or more, and may be 2.5% or more, or 3% or more. When the antireflection layer is a radiation-curable resin layer, the total light transmittance may be a value before curing or a value after curing.

The haze value and total light transmittance of the above antireflection layer can be measured by the methods specified in JIS K7136 and JIS K7361-1, respectively, and can be controlled by the type, thickness, type and amount of colorant, etc. I can do it.

(light diffusion layer)
The light diffusion layer is a layer having a function of diffusing light, and is preferably a resin layer made of resin. Although the light diffusion layer is not limited, it is preferable that the light diffusion layer contains a light diffusion agent. That is, it is preferable that the light diffusing layer includes a light diffusing agent dispersed in the resin layer. The above-mentioned light diffusing agents may be used alone or in combination of two or more.

The refractive index of the light diffusing agent is preferably 1.4 to 1.7, more preferably 1.41 to 1.68, even more preferably 1.42 to 1.66. When the refractive index is within the above range, the difference in L ^* (SCE), the difference in a ^* (SCE), and the difference in b ^* (SCE) measured from both sides can be made smaller, and the optical semiconductor device brightness can be made higher. Further, the sheet for encapsulating an optical semiconductor element also has excellent light diffusing properties.

The absolute value of the refractive index difference between the light diffusing agent and the resin constituting the light diffusing layer (the resin layer excluding the light diffusing agent in the light diffusing layer) is determined from the viewpoint of more efficiently reducing brightness unevenness in optical semiconductor devices. Therefore, it is preferably 0.001 or more, more preferably 0.01 or more, still more preferably 0.02 or more, particularly preferably 0.03 or more, and may be 0.04 or more, or 0.05 or more. . In addition, the absolute value of the refractive index difference between the light diffusing agent and the resin is preferably 5 or less, more preferably 4 or less, and more preferably 4 or less, from the viewpoint of preventing the haze value from becoming too high and displaying a high-definition image. Preferably it is 3 or less.

The light diffusing agent has an appropriate refractive index difference with the resin constituting the light diffusing layer, and imparts diffusion performance to the light diffusing layer. Examples of the material constituting the light diffusing agent include inorganic materials and polymer materials. Examples of the inorganic material include silica, calcium carbonate, aluminum hydroxide, magnesium hydroxide, clay, talc, and metal oxides. Examples of the polymer material include silicone resin, acrylic resin (including polymethacrylate resin such as polymethyl methacrylate), polystyrene resin, polyurethane resin, melamine resin, polyethylene resin, and epoxy resin. .

The material constituting the light diffusing agent is preferably a polymeric material, more preferably a silicone resin. Thereby, the light extraction efficiency of the light diffusion layer can be further increased, and the brightness of the optical semiconductor device can be further increased. Further, the sheet for encapsulating an optical semiconductor element also has excellent light diffusing properties.

The shape of the light diffusing agent is not particularly limited, and may be, for example, a true sphere, a flat shape, or an irregular shape.

The light diffusing agent is preferably light diffusing fine particles. The average particle diameter of the light-diffusing fine particles is preferably 0.1 μm or more, more preferably 0.15 μm or more, and even more preferably 0.1 μm or more, from the viewpoint of imparting appropriate light-diffusing performance to the optical semiconductor device sealing sheet. .2 μm or more, particularly preferably 0.25 μm or more. Furthermore, from the viewpoint of preventing the haze value from becoming too high and displaying a high-definition image, the average particle diameter of the light-diffusing fine particles is preferably 12 μm or less, more preferably 10 μm or less, and still more preferably 8 μm or less. It is. The average particle diameter can be measured using, for example, a Coulter counter.

From the viewpoint of imparting appropriate light diffusion performance to the optical semiconductor element sealing sheet, the content of the light diffusion agent in the light diffusion layer is 5 parts by mass based on 100 parts by mass of the resin constituting the light diffusion layer. The amount is preferably at least 10 parts by mass, more preferably at least 10 parts by mass, even more preferably at least 20 parts by mass, particularly preferably at least 30 parts by mass. In addition, from the viewpoint of preventing the haze value from becoming too high and displaying a high-definition image, the content of the light diffusing agent is 80 parts by mass or less based on 100 parts by mass of the resin constituting the light diffusing layer. Preferably, it is more preferably 70 parts by mass or less.

The haze value (initial haze value) of the light diffusion layer is not particularly limited, but is preferably 30% or more, more preferably 40% or more, from the viewpoint of achieving better light diffusion and efficiently reducing brightness unevenness of the optical semiconductor device. % or more, more preferably 50% or more, particularly preferably 60% or more, and may be 70% or more, 80% or more, 90% or more, 95% or more, or 97% or more. Note that the upper limit of the haze value of the light diffusion layer is not particularly limited, and may be 100% or 99%. When the light diffusion layer is a radiation-curable resin layer, the haze value may be a value before curing or a value after curing.

The total light transmittance of the light diffusion layer is not particularly limited, but from the viewpoint of having excellent light extraction efficiency and ensuring the brightness of the optical semiconductor device, the total light transmittance of the light diffusion layer is preferably 40% or more, more preferably 60% or more, and still more preferably It is 70% or more, more preferably 80% or more. Further, the upper limit of the total light transmittance of the light diffusion layer is not particularly limited, but may be less than 100%, 99.9% or less, or 99% or less. When the light diffusion layer is a radiation-curable resin layer, the total light transmittance may be a value before curing or a value after curing.

The haze value and total light transmittance of the above-mentioned light diffusing layer can be measured by the methods specified in JIS K7136 and JIS K7361-1, respectively, and are determined by the type and thickness of the light diffusing layer, the type and amount of the light diffusing agent. It can be controlled by etc.

(Non-light diffusion layer)
The non-light-diffusing layer is a colorless and transparent layer that is not intended to exhibit a light-diffusing function, and is preferably a resin layer made of resin.

The haze value (initial haze value) of the non-light diffusing layer is not particularly limited, but from the viewpoint of achieving excellent light extraction efficiency and excellent brightness of the optical semiconductor device, it is preferably less than 30%, more preferably 10%. % or less, more preferably 5% or less, particularly preferably 1% or less, and may be 0.5% or less. Note that the lower limit of the haze value of the non-light-diffusing layer is not particularly limited. When the non-light diffusing layer is a radiation-curable resin layer, the haze value may be a value before curing or a value after curing.

The total light transmittance of the non-light diffusing layer is not particularly limited, but from the viewpoint of having excellent light extraction efficiency and ensuring the brightness of the optical semiconductor device, the total light transmittance of the non-light diffusing layer is preferably 60% or more, more preferably 70% or more, and even more preferably is 80% or more, particularly preferably 90% or more. Further, the upper limit of the total light transmittance of the non-light diffusing layer is not particularly limited, but may be less than 100%, 99.9% or less, or 99% or less. When the non-light diffusing layer is a radiation-curable resin layer, the total light transmittance may be a value before curing or a value after curing.

The haze value and total light transmittance of the non-light diffusing layer can be measured by the methods specified in JIS K7136 and JIS K7361-1, respectively, and can be controlled by the type and thickness of the non-light diffusing layer. .

The content of the colorant and/or light diffusing agent in the non-light diffusing layer is determined based on the weight of the resin constituting the non-light diffusing layer, from the viewpoint of achieving excellent light extraction efficiency and brightness of the optical semiconductor device. The amount is preferably less than 0.01 parts by mass, more preferably 0.005 parts by mass or less.

<Resin layer>
When the antireflection layer, the light diffusion layer, and the non-light diffusion layer are the resin layers, examples of the resin constituting the resin layer include known or commonly used resins, such as acrylic resins and urethane resins. Acrylate resin, urethane resin, rubber resin, epoxy resin, epoxy acrylate resin, oxetane resin, silicone resin, silicone acrylic resin, polyester resin, polyether resin (polyvinyl ether, etc.), polyamide resin , fluororesins, vinyl acetate/vinyl chloride copolymers, modified polyolefins, and the like. The above resins may be used alone or in combination of two or more. The resins constituting the antireflection layer, the light diffusion layer, and the non-light diffusion layer may be the same or different.

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

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

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

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

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

Among the above (meth)acrylic acid alkyl esters, linear or branched fatty acids having 1 to 20 carbon atoms (preferably 1 to 14, more preferably 2 to 10, even more preferably 2 to 6) carbon atoms are used. Preferred are (meth)acrylic acid alkyl esters having group hydrocarbon groups. When the number of carbon atoms is within the above range, the glass transition temperature of the acrylic resin can be easily adjusted, and the adhesiveness of the resin layer can be made more appropriate.

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

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

The above-mentioned hydrocarbon group-containing (meth)acrylic acid ester preferably includes (meth)acrylic acid alkyl ester having a linear or branched aliphatic hydrocarbon group, and further includes an alicyclic hydrocarbon group. It is more preferable to include a (meth)acrylic acid ester having a group. In this case, the adhesiveness of the resin layer is well balanced and the sealing properties of the optical semiconductor element are more excellent.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Various common solvents may be used in polymerizing the monomer components. Examples of the solvent include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane and methylcyclohexane. alicyclic hydrocarbons; organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. The above solvents may be used alone or in combination of two or more.

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

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

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

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

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

The amount of the photopolymerization initiator used is preferably 0.005 to 1 part by mass, more preferably 0.01 to 0 parts by mass, based on 100 parts by mass of all monomer components constituting the acrylic resin. .7 parts by weight, more preferably 0.18 to 0.5 parts by weight. When the above usage amount is 0.005 parts by mass or more (particularly 0.18 parts by mass or more), it is easy to control the molecular weight of the acrylic resin to a small value, and the residual stress of the resin layer increases, resulting in better step absorbability. There is a tendency to

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

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

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

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

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

The resin layer may contain other components other than the above components in the antireflection layer, the light diffusion layer, and the non-light diffusion layer, as long as the effects of the present invention are not impaired. Other ingredients mentioned above include crosslinking accelerators, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), oligomers, anti-aging agents, fillers (metal powders, organic fillers, inorganic fillers, etc.) ), antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, granular materials, foil-like materials, etc. The above-mentioned other components may be used alone or in combination of two or more.

The thickness of each of the first sealing layer, the second sealing layer, and the third sealing layer is, for example, 5 to 480 μm. The thickness of the first sealing layer is preferably 5 to 100 μm, more preferably 10 to 80 μm, and still more preferably 20 to 70 μm. When the thickness of the first sealing layer is 5 μm or more, the sealability of the semiconductor element becomes better. When the thickness of the first sealing layer is 100 μm or less, it is easier to ensure brightness when the optical semiconductor element emits light.

The thickness of the second sealing layer is preferably 5 to 100 μm, more preferably 10 to 80 μm, and even more preferably 20 to 70 μm. When the thickness of the second sealing layer is 5 μm or more, the sealability of the semiconductor element becomes better. When the thickness of the second sealing layer is 100 μm or less, it is easier to ensure brightness when the optical semiconductor element emits light.

The thickness of the third sealing layer is preferably 30 to 480 μm, more preferably 40 to 380 μm, and still more preferably 50 to 280 μm. When the thickness of the third sealing layer is 30 μm or more, the sealing performance of the semiconductor element becomes better. When the thickness of the third sealing layer is 480 μm or less, when separating adjacent optical semiconductor devices in a tiling state, damage to the optical semiconductor element sealing sheet and adhesion of sheets of adjacent optical semiconductor devices is more likely to occur. Hard to happen.

The thickness of the sealing portion (for example, a laminate having both ends of the first sealing layer and the third sealing layer) is, for example, 100 to 500 μm, preferably 120 to 400 μm, and more preferably 150 to 300 μm. It is. When the thickness is 100 μm or more, the sealing properties of the optical semiconductor device will be better. When the thickness is 500 μm or less, the handling property as a sheet and the reworkability in the tiling process are better, and the side surfaces are less likely to become sticky.

In the case of resin layers, the first sealing layer, the second sealing layer, and the third sealing layer are formed by, for example, applying the resin composition forming each layer to the release-treated surface of a release liner. After forming the layer, the resin composition layer can be produced by removing the solvent by heating or irradiating active energy rays to polymerize the monomer components, and if necessary further heating to solidify the resin composition layer.

The resin composition may be in any form. For example, when the resin layer is an adhesive layer, the resin composition (adhesive composition) may be an emulsion type, a solvent type (solution type), an active energy ray-curable type, a heat melt type (hot melt type), etc. It's okay. Among these, solvent-type and active energy ray-curable types are preferred since they are easy to obtain adhesive layers with excellent productivity.

Examples of the resin composition include a resin composition containing a resin as an essential component, a mixture of monomers (monomer components) constituting the resin (sometimes referred to as a "monomer mixture"), or a partial polymerization thereof. Examples include resin compositions containing esters as essential components. Examples of the former include so-called solvent-type resin compositions. Also. Examples of the latter include so-called active energy ray-curable resin compositions. The above-mentioned "monomer mixture" means a mixture containing monomer components constituting a polymer. The above-mentioned "partially polymerized product" may also be referred to as "prepolymer", "syrup", etc., and is a product in which one or more of the monomer components in the monomer mixture is partially polymerized. means a composition containing

The above resin composition can be produced by a known or commonly used method. For example, a solvent-type resin composition can be produced by mixing additives such as a coloring agent and a light diffusing agent, if necessary, into a solution containing the resin. For example, an active energy ray-curable resin composition can be produced by mixing additives, if necessary, with a mixture of monomer components constituting the resin or a partial polymer thereof.

Note that a known coating method may be used for applying (coating) the resin composition. For example, coaters such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, a comma coater, and a direct coater may be used.

The heat drying temperature of the solvent-type resin composition is preferably 40 to 200°C, more preferably 50 to 180°C, and still more preferably 70 to 170°C. The drying time may be any suitable time, and is, for example, 5 seconds to 20 minutes, preferably 5 seconds to 10 minutes, more preferably 10 seconds to 5 minutes.

When forming a resin layer by irradiation with active energy rays, the resin layer can be formed while producing the resin from the monomer components. The above-mentioned monomer component can be partially polymerized to syrup before irradiation with active energy rays. A high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, etc. can be used for ultraviolet irradiation.

(Base material part)
The base material part serves as a support for the sealing part in the sheet for encapsulating an optical semiconductor element, and by providing the base material part, the sheet for encapsulating an optical semiconductor element has excellent handling properties. The base material portion may be a single layer, or may be a multilayer having the same or different compositions, thicknesses, etc. When the base material part is multi-layered, each layer may be bonded together by another layer such as an adhesive layer. In addition, when sealing an optical semiconductor element using an optical semiconductor element sealing sheet, the base material layer used for the base material part is the part that is attached to the substrate provided with the optical semiconductor element together with the sealing part. The "base material" does not include a release liner that is peeled off when the optical semiconductor element sealing sheet is used (applied) or a surface protection film that merely protects the surface of the base material. The base material portion is laminated, for example, on the third sealing layer.

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

The base material layer may be various optical films such as an antireflection (AR) film, a polarizing plate, and a retardation plate. When the base material portion has an optical film, the optical semiconductor element sealing sheet can be applied to the optical member as it is.

The thickness of the plastic film is preferably 20 to 200 μm, more preferably 40 to 150 μm. When the thickness is 20 μm or more, the supportability and handleability of the sheet for encapsulating an optical semiconductor device are further improved. When the thickness is 200 μm or less, the thickness of the optical semiconductor element sealing sheet can be reduced, and the optical semiconductor device can be made even thinner.

The surface of the base portion on the side where the sealing portion is provided may be subjected to, for example, corona discharge treatment, plasma treatment, sand mat processing treatment, ozone exposure treatment, etc., for the purpose of improving adhesion and retention with the sealing portion. Physical treatments such as flame exposure treatment, high-voltage electric shock exposure treatment, and ionizing radiation treatment; chemical treatments such as chromic acid treatment; and surface treatments such as adhesion-facilitating treatment with a coating agent (undercoat). The surface treatment for improving adhesion is preferably applied to the entire surface of the base member on the side of the sealing part.

The thickness of the base material portion is preferably 5 μm or more, more preferably 10 μm or more, from the viewpoint of excellent support function and surface scratch resistance. The thickness of the base material portion is preferably 300 μm or less, more preferably 200 μm or less, from the viewpoint of better transparency.

(Sheet for encapsulating optical semiconductor elements)
As described above, the optical semiconductor element sealing sheet may include the functional layer such as a surface treatment layer (for example, the anti-glare treatment layer, the anti-reflection treatment layer, the hard coat treatment layer, etc.). . By having such a configuration, when the optical semiconductor device is applied to a display, it is possible to suppress the gloss of the display and the reflection of light, improve the appearance of the display, and improve the scratch resistance of the display surface. I can do it. The anti-glare treatment layer, the anti-reflection treatment layer, and the hard coat treatment layer may be a single layer having two or more of these functions, or may be different layers. It is preferable that the functional layer is provided on the surface of the base portion (particularly on the surface opposite to the sealing portion). Each of the anti-glare treated layer, anti-reflection treated layer, and hard coat treated layer may have only one layer, or may have two or more layers.

As the above-mentioned anti-reflection treatment, any known anti-reflection treatment can be applied without any particular restriction. Specifically, an optical thin film whose thickness and refractive index are strictly controlled or the above-mentioned optical thin film is coated on the base material. This can be carried out by forming an antireflection treatment layer in which more than one layer is laminated. The antireflection treatment layer exhibits an antireflection function by canceling out the reversed phases of incident light and reflected light using the interference effect of light. The wavelength range of visible light that exhibits the antireflection function is, for example, 380 to 780 nm, and the wavelength range with particularly high visibility is 450 to 650 nm, and the reflectance at the center wavelength of 550 nm is minimized. It is preferable to design the antireflection treatment layer in such a manner.

The above-mentioned antireflection treatment layer generally includes a multilayer antireflection treatment layer having a laminated structure of 2 to 5 optical thin layers (thin films whose thickness and refractive index are strictly controlled). By forming multiple layers of components with different refractive indexes to a predetermined thickness, the degree of freedom in optical design of the anti-reflection treatment layer is increased, the anti-reflection effect can be further improved, and the spectral reflection characteristics also improve in the visible light region. It becomes possible to make it uniform (flat). Since high thickness accuracy is required in the optical thin film, each layer is generally formed by a dry method such as vacuum evaporation, sputtering, or CVD.

As the above-mentioned anti-glare treatment, any known anti-glare treatment can be applied without particular limitation, and for example, it can be carried out by forming an anti-glare treatment layer on the base material portion. As the anti-glare treatment layer, any known anti-glare treatment layer can be used without any limitation, and is generally formed as a layer in which inorganic or organic particles as an anti-glare agent are dispersed in a resin.

The anti-glare treatment layer is formed using, for example, an anti-glare treatment layer forming material containing a resin, particles, and a thixotropy agent. By aggregating the particles and the thixotropy imparting agent, convex portions are formed on the surface of the anti-glare treatment layer. With this configuration, the anti-glare treatment layer has excellent display characteristics that combine anti-glare properties and prevention of white blur, and the appearance is improved even though the anti-glare treatment layer is formed using particle aggregation. It is possible to prevent the generation of protrusions on the surface of the anti-glare treatment layer, which would be a drawback, and improve the yield of the product.

The haze value (initial haze value) of the optical semiconductor element sealing sheet in a state where the functional layer is not laminated is not particularly limited, but the light diffusivity is further improved, the effect of suppressing brightness unevenness and the designability are further improved. From the viewpoint of being excellent, it is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more, and particularly preferably 95% or more. Note that the upper limit of the haze value is not particularly limited. The haze value may be a value measured from either side. When the optical semiconductor element sealing sheet includes a radiation-curable resin layer, the haze value may be a value before curing the radiation-curable resin layer, or a value after curing the radiation-curable resin layer. Further, in the sheet for encapsulating an optical semiconductor element, in a state where a functional layer is laminated on one side thereof, it is preferable that the haze value (initial haze value) measured from the functional layer side is within the above range.

The total light transmittance of the sheet for encapsulating an optical semiconductor element in a state where the functional layer is not laminated is not particularly limited, but from the viewpoint of further improving the antireflection function and contrast of metal wiring in an optical semiconductor device, it is 30. % or less, more preferably 20% or less, still more preferably 5% or less. Further, the total light transmittance is preferably 0.5% or more from the viewpoint of superior light extraction efficiency and ensuring brightness of the optical semiconductor device. When the optical semiconductor element sealing sheet includes a radiation-curable resin layer, the total light transmittance may be a value before curing the radiation-curable resin layer, or a value after curing the radiation-curable resin layer. .

The sheet for encapsulating an optical semiconductor element preferably has a total light transmittance of 0.5 to 30%, more preferably 0.5 to 30%, when the functional layer is laminated on one side of the sheet. It is 1 to 25%, more preferably 2 to 20%, particularly preferably 3 to 15%. When the total light transmittance is 0.5% or more, the light extraction efficiency is excellent and the brightness of the optical semiconductor device can be further ensured. When the total light transmittance is 30% or less, the antireflection function and contrast of metal wiring in an optical semiconductor device can be further improved.

The haze value and total light transmittance of the above sheet for encapsulating optical semiconductor elements can be measured by the methods specified in JIS K7136 and JIS K7361-1, respectively, and the haze value and total light transmittance of each layer constituting the sheet for encapsulating optical semiconductor elements can be measured by the methods specified in JIS K7136 and JIS K7361-1, respectively. It can be controlled by the stacking order, type, thickness, etc.

The above-mentioned sheet for encapsulating an optical semiconductor element has a functional layer laminated on one side thereof, and L ^* (SCE ) is preferably 5 to 60, more preferably 8 to 40, even more preferably 10 to 20. Light reflected by an object includes specular reflection light and diffuse reflection light, and specular reflection light is light that is difficult to recognize with the naked eye. L ^* (SCE) is a measurement of reflected light that does not include specularly reflected light, and when L ^* (SCE) is 60 or less, the image display device has excellent design when viewed with the naked eye. When L ^* (SCE) is 5 or more, the light extraction efficiency is excellent, and the brightness of the optical semiconductor device can be further ensured. Further, it is preferable that the L ^* (SCE) of the optical semiconductor element sealing sheet in a state in which the functional layer is not laminated is within the above range. Specifically, L ^* (SCE) can be measured by the method described in Examples.

The above optical semiconductor element sealing sheet has a functional layer laminated on one side and has a ^* (SCE) when measured from at least one side (preferably both sides) with a field of view of 10° and a light source of D65. ) is preferably -5 to 5, more preferably -3 to 3, still more preferably -2 to 2. When a ^* (SCE) is within the above range, the brightness and color tone of the light emitted by the optical semiconductor element and the light recognized by the viewer through the optical semiconductor element sealing sheet are comparable, and the appearance is good. Moreover, it is preferable that the a ^* (SCE) of the optical semiconductor element sealing sheet in a state in which the functional layer is not laminated is within the above range. a ^* (SCE) can be specifically measured by the method described in Examples.

The above-mentioned sheet for encapsulating an optical semiconductor device has b ^* (SCE) when measured with a functional layer laminated on one side and under conditions of a 10° field of view from at least one side (preferably both sides) and a light source of D65. ) is preferably -5 to 5, more preferably -3 to 3, still more preferably -2 to 2. When b ^* (SCE) is within the above range, the brightness and color tone of the light emitted by the optical semiconductor element and the light recognized by the viewer through the optical semiconductor element sealing sheet are comparable, and the appearance is good. Moreover, it is preferable that the b ^* (SCE) of the optical semiconductor element sealing sheet in a state in which the functional layer is not laminated is within the above range. b ^* (SCE) can be specifically measured by the method described in Examples.

The closer L ^* (SCE) is to 1, the better the design. In this specification, L ^* a ^* b ^* (SCE) can be measured using a known or commonly used spectrophotometric colorimeter. The measurement of L ^* a ^* b ^* (SCE) may be performed with a transparent layer attached to the sealing part. For example, when the sealing portion has adhesive properties, handling during measurement is improved. Examples of the transparent layer include a release liner and a plastic substrate. The transparent layer preferably has a haze value of 30% or less and/or a total light transmittance of 80% or more from the viewpoint of having a small influence on L ^* a ^* b ^* (SCE). Specifically, the above L ^* a ^* b ^* (SCE) can be measured, for example, by the method described in Examples. In addition, when the optical semiconductor element sealing sheet includes a radiation-curable resin layer, it is desirable to measure in a state closer to the state in use, so each value after curing of the radiation-curable resin layer ( L ^* ₁ , a ^* ₁ , b ^* ₁ , L ^* ₂ , a ^* ₂ , b ^* ₂ , L ^* ₁ - L ^* ₂ , a ^* ₁ - ^{a *} ₂ , and b ^* ₁ - b ^* ₂ ) are It may be within the above range, and each value of the radiation curable resin layer before curing may be within the above range.

The circular diameter measured by the light diffusion effect confirmation test below using a measurement sample in which the sealing part (first sealing layer) of the optical semiconductor element sealing sheet was bonded to a glass plate was 20 mm or more. The length is preferably 25 mm or more, and even more preferably 26 mm or more. When the diameter of the circular shape is 20 mm or more, the light diffusivity is excellent and uneven brightness is further suppressed. In addition, the light diffusion effect of the optical semiconductor element sealing sheet described above was confirmed using a measurement sample in which a functional layer was laminated on one side and the sealing part (first sealing layer) was bonded to a glass plate. It is preferable that the diameter of the circle measured by the test is within the above range.
<Light diffusion effect confirmation test>
When an LED lamp is installed on the screen, a glass plate is brought into close contact with the LED lamp, and light is irradiated from the LED lamp onto the screen through the glass plate, a circular light with a diameter of 16 mm appears on the screen. is the position of the LED lamp. Then, with the glass plate side of the measurement sample in which the sealing part (first sealing layer) of the optical semiconductor element sealing sheet was bonded to the glass plate in close contact with the LED lamp, the glass plate and the The diameter of the circular light that appears when light is irradiated onto the screen through the optical semiconductor element sealing sheet is measured.

The thickness of the sheet for encapsulating optical semiconductor elements of the present invention is 10 to 600 μm from the viewpoint of more efficiently reducing color cast while improving the antireflection function and contrast of metal wiring in image display devices. It is preferably from 20 to 550 μm, even more preferably from 30 to 500 μm, even more preferably from 40 to 450 μm, particularly preferably from 50 to 400 μm. In addition, when the sheet for encapsulating an optical semiconductor element of the present invention includes a base material part, the base material part is included in the thickness of the sheet for encapsulating an optical semiconductor element of the present invention, but the release liner is included in the thickness of the sheet for encapsulating an optical semiconductor element of the present invention. This is not included in the thickness of the element sealing sheet.

The sheet for encapsulating an optical semiconductor element of the present invention has excellent light diffusivity and light extraction efficiency. Therefore, according to the sheet for encapsulating an optical semiconductor element of the present invention, in a state in which an optical semiconductor element is sealed, the sheet has excellent design, high brightness, and less uneven brightness. By using the optical semiconductor element sealing sheet of the present invention, the appearance of the optical semiconductor element is good when the optical semiconductor element is not lit, and the light emitted from the optical semiconductor element is efficiently used when the optical semiconductor element is lit. It is possible to provide an optical semiconductor device that allows light to pass through in a diffused state.

[Release liner]
The release liner is an element for covering and protecting the surface of the sheet for encapsulating an optical semiconductor element, and when the sheet for encapsulating an optical semiconductor element is attached to a substrate on which an optical semiconductor element is arranged, the sheet is be stripped from.

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

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

[Method for manufacturing a sheet for encapsulating optical semiconductor elements]
An embodiment of the method for manufacturing an optical semiconductor device sealing sheet of the present invention will be described. For example, the optical semiconductor element sealing sheet 1 shown in FIG. Layer 22 and third sealing layer 23 are produced separately. One of the release liners bonded to the first sealing layer 21 is the release liner 3.

Next, one side of the release liner attached to the third sealing layer 23 is peeled off to expose the surface of the third sealing layer 23, and the exposed surface is bonded to the base member 4. After that, one side of the release liner affixed to the second sealing layer 22 is peeled off, and the release liner on the surface of the third sealing layer 23 is peeled off, and the second sealing layer 22 is attached to the exposed surface of the third sealing layer 23. Attach the exposed surfaces of the

Next, one of the release liners affixed to the first sealing layer 21 (the release liner that is not the release liner 3) is peeled off, and the release liner on the surface of the second sealing layer 22 is peeled off to expose the second sealant. The exposed surface of the first sealing layer 21 is bonded to the surface of the layer 22. Note that the various layers can be laminated using a known roller or laminator. In this way, the optical semiconductor element shown in FIG. The sealing sheet 1 can be produced.

An optical semiconductor device can be obtained by bonding a first sealing layer onto a substrate on which an optical semiconductor element is placed and sealing the optical semiconductor element using the optical semiconductor device sealing sheet of the present invention. can. Specifically, first, the release liner is peeled off from the optical semiconductor device sealing sheet of the present invention to expose the first sealing layer. Then, the optical semiconductor element sealing of the present invention is applied to the substrate surface on which the optical semiconductor element is arranged, of the optical member comprising a substrate and an optical semiconductor element (preferably a plurality of optical semiconductor elements) arranged on the substrate. The first sealing layer surface, which is the exposed surface of the sheet, is bonded together, and when the optical member includes a plurality of optical semiconductor elements, the radiation first sealing layer fills the gaps between the plurality of optical semiconductor elements. and seal the plurality of optical semiconductor elements at once. In this way, an optical semiconductor element can be sealed using the optical semiconductor device sealing sheet of the present invention. Moreover, an optical semiconductor element may be sealed using the sheet for encapsulating an optical semiconductor device of the present invention by bonding them together in a reduced pressure environment or while applying pressure. Examples of such a method include methods disclosed in JP-A-2016-29689 and JP-A-6-97268.

[Optical semiconductor device]
An optical semiconductor device can be manufactured using the optical semiconductor element sealing sheet of the present invention. An optical semiconductor device manufactured using the optical semiconductor element sealing sheet of the present invention includes a substrate, an optical semiconductor element disposed on the substrate, and a book that seals the optical semiconductor element with the sealing portion. A sheet for encapsulating an optical semiconductor element of the invention or a cured product obtained by curing the sheet. The above-mentioned cured product is a cured product obtained by curing the radiation-curable resin layer by radiation irradiation when the sheet for encapsulating an optical semiconductor element of the present invention includes a radiation-curable resin layer.

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

In the above-mentioned optical semiconductor device, the sheet for encapsulating optical semiconductor elements of the present invention has excellent followability to irregularities when the optical semiconductor element is used as a convex part and the gaps between a plurality of optical semiconductor elements are used as recesses. In order to have excellent followability and embeddability, it is preferable to seal a plurality of optical semiconductor elements at once.

FIG. 2 shows an embodiment of an optical semiconductor device using the optical semiconductor element sealing sheet 1 shown in FIG. The optical semiconductor device 10 shown in FIG. 2 includes a substrate 5, a plurality of optical semiconductor elements 6 arranged on one surface of the substrate 5, and an optical semiconductor element sealing sheet 1 for sealing the optical semiconductor elements 6. Be prepared. The optical semiconductor element sealing sheet 1 is obtained by removing the release liner 3 from the optical semiconductor element sealing sheet 1 shown in FIG. The plurality of optical semiconductor elements 6 are collectively sealed in a sealing part. The first sealing layer 21 follows the uneven shape formed by the plurality of optical semiconductor elements 6, adheres to the optical semiconductor element 6 and the substrate 5, and embeds the optical semiconductor element 6.

In the optical semiconductor device 10 shown in FIG. 2, the optical semiconductor element 6 is completely embedded and sealed in the first sealing layer 21, and the second sealing layer 22 and the third sealing layer It is indirectly sealed by layer 23. That is, the optical semiconductor element 6 is sealed by the sealing part 2 made of a laminate of a first sealing layer 21 , a second sealing layer 22 , and a third sealing layer 23 . The above-mentioned optical semiconductor device is not limited to such an embodiment, and a part of the optical semiconductor element 6 protrudes from the first sealing layer 21, and the part protrudes from the second sealing layer 22 or the second sealing layer 21. It is embedded in the sealing layer 22 and the third sealing layer 23, and the first sealing layer 21 and the second sealing layer 22, or the first sealing layer 21, the second sealing layer 22, and the third sealing layer The optical semiconductor element 6 may be completely buried and sealed by the sealing layer 23 .

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

FIG. 3 shows an embodiment of an optical semiconductor device manufactured by arranging a plurality of optical semiconductor devices. In the optical semiconductor device 20 shown in FIG. 3, a total of 16 optical semiconductor devices 10, four in the vertical direction and four in the horizontal direction, are arranged in a tile shape (tiling) in the planar direction. At the boundary 20a between two adjacent optical semiconductor devices 10, the optical semiconductor devices 10 are adjacent to each other.

The optical semiconductor device is preferably a backlight for a liquid crystal screen, and particularly preferably a full-surface direct type backlight. Moreover, an image display device can be obtained by combining the above-described backlight and a display panel. When the optical semiconductor device is a backlight for a liquid crystal screen, the optical semiconductor element is an LED element. For example, in the backlight, a metal wiring layer for sending a light emission control signal to each LED element is laminated on the substrate. LED elements that emit red (R), green (G), and blue (B) light are alternately arranged on the substrate of the display panel via metal wiring layers. The metal wiring layer is made of metal such as copper and reflects the light emitted from each LED element, reducing the visibility of the image. Furthermore, the light emitted by each LED element of each color of RGB is mixed, resulting in a decrease in contrast.

Further, it is preferable that the optical semiconductor device is a self-luminous display device. Moreover, an image display device can be obtained by combining the above self-luminous display device and a display panel as necessary. When the optical semiconductor device is a self-luminous display device, the optical semiconductor element is an LED element. Examples of the self-luminous display device include an organic electroluminescence (organic EL) display device and the backlight described above. For example, in the self-luminous display device, a metal wiring layer for sending a light emission control signal to each LED element is laminated on the substrate. LED elements that emit light of red (R), green (G), and blue (B) colors are alternately arranged on a substrate with metal wiring layers interposed therebetween. The metal wiring layer is made of metal such as copper, and displays each color by adjusting the degree of light emission of each LED element.

The optical semiconductor element sealing sheet of the present invention has an optical semiconductor device that is used by being folded, for example, a foldable image display device (flexible display) (particularly a foldable image display device (foldable display)). It can be used for optical semiconductor devices. Specifically, it can be used for foldable backlights, foldable self-luminous display devices, and the like.

The optical semiconductor device sealing sheet of the present invention has excellent followability and embeddability for optical semiconductor devices, and is therefore suitable for both cases where the optical semiconductor device is a mini LED display device and a micro LED display device. can be used.

[Method for manufacturing optical semiconductor device]
The above-mentioned optical semiconductor device includes, for example, a substrate, an optical semiconductor element disposed on the substrate, and a sheet for sealing an optical semiconductor element of the present invention or a radiation-curable resin layer that seals the optical semiconductor element and is cured. The optical semiconductor device can be manufactured by a manufacturing method including at least a dicing step of dicing a laminate including a cured product and a dicing step of obtaining an optical semiconductor device. The above-mentioned cured product is a cured product obtained by curing the sheet for encapsulating an optical semiconductor element of the present invention by radiation irradiation. Specifically, the cured product is a cured product obtained by curing the sheet for encapsulating an optical semiconductor element of the present invention. It includes a cured product cured by radiation irradiation.

The manufacturing method further includes irradiating a laminate including the substrate, an optical semiconductor element disposed on the substrate, and the optical semiconductor element sealing sheet for sealing the optical semiconductor element. The method may further include a radiation irradiation step of curing the radiation-curable resin layer to obtain the cured product.

The above manufacturing method includes, before the radiation irradiation step, bonding the optical semiconductor element sealing sheet to the optical semiconductor element provided on the substrate, and sealing the optical semiconductor element with the sealing part. It may also include a sealing step.

Further, the manufacturing method may further include a tiling step of arranging the plurality of optical semiconductor devices obtained in the dicing step so as to be in contact with each other in a planar direction. Hereinafter, a method for manufacturing the optical semiconductor device 10 shown in FIG. 2 and the optical semiconductor device 20 shown in FIG. 3 will be described with appropriate reference.

(Sealing process)
In the above-mentioned sealing step, the optical semiconductor element sealing sheet of the present invention is bonded to the substrate on which the optical semiconductor element is arranged, and the optical semiconductor element is sealed by the sealing portion. In the above-mentioned sealing step, specifically, as shown in FIG. The optical semiconductor element sealing sheet 1 is bonded to the surface of the substrate 5 on which the optical semiconductor element 6 is placed, and the optical semiconductor element 6 is placed in the sealing portion as shown in FIG. Embed in 2.

When the optical semiconductor element sealing sheet 1 includes a radiation-curable resin layer, as shown in FIG. 4, the substrate 5 used for bonding is arranged in a plane direction more than the substrate 5 in the optical semiconductor device 10 shown in FIG. The optical semiconductor element 6 is not arranged near the edge of the substrate 5. Moreover, in this case, the optical semiconductor element sealing sheet 1 to be bonded extends wider in the plane direction than the substrate 5 used for bonding. That is, the area of the surface of the optical semiconductor element sealing sheet 1 facing the substrate 5 to be bonded together in the sealing process is the area of the surface of the substrate 5 facing the optical semiconductor element sealing sheet 1 to be bonded together in the sealing process. larger than the area of This allows the area of the laminate of the optical semiconductor element sealing sheet 1 and the substrate 5 that will be used for the optical semiconductor device to be sufficiently cured in the subsequent radiation irradiation step, and the optical semiconductor element sealing sheet 1 and the substrate 5 to be cured sufficiently in the subsequent radiation irradiation step. This is because the vicinity of the edges of the substrate 5 where there is a possibility that the curing is insufficient will be diced and removed in a later dicing step.

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

(Radiation irradiation process)
In the radiation irradiation step, radiation is applied to a laminate (for example, a laminate obtained in the encapsulation step) in which the optical semiconductor element sealing sheet is bonded to the substrate on which the optical semiconductor element is arranged. is irradiated to cure the radiation-curable resin layer. As mentioned above, examples of the radiation include electron beams, ultraviolet rays, α rays, β rays, γ rays, and X rays. Among these, ultraviolet light is preferred. The temperature during radiation irradiation is, for example, in the range from room temperature to 100° C., and the irradiation time is, for example, 1 minute to 1 hour.

(dicing process)
In the dicing step, a substrate, an optical semiconductor element disposed on the substrate, and a cured product obtained by curing the optical semiconductor element sealing sheet or radiation-curable resin layer of the present invention for sealing the optical semiconductor element A laminate comprising the above is diced. Here, when the above-mentioned laminate includes the above-mentioned cured product, in the laminate subjected to the dicing process, the cured product of the optical semiconductor element sealing sheet and the substrate 5 are used for the finally obtained optical semiconductor device, as described above. 10 extends wider in the plane direction. In the dicing step, the cured product of the optical semiconductor element sealing sheet and the side edges of the substrate are diced and removed. Specifically, dicing is performed at the position indicated by the chain line shown in FIG. 6, and the side edges are removed. The above-mentioned dicing can be performed by a known or commonly used method, for example, by using a dicing blade or by laser irradiation. In this way, for example, the optical semiconductor device 10 shown in FIG. 2 can be manufactured.

(Tiling process)
In the tiling step, the plurality of optical semiconductor devices obtained in the dicing step are arranged and tiled so as to be in contact with each other in a planar direction. In this way, for example, the optical semiconductor device 20 shown in FIG. 3 can be manufactured.

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

Manufacturing example 1
(Preparation of non-light diffusing layer 1)
Butyl acrylate (BA) 67 parts by mass, cyclohexyl acrylate (CHA) 14 parts by mass, 4-hydroxybutyl acrylate (4HBA) 27 parts by mass, 2-hydroxyethyl acrylate (HEA) 9 parts by mass, 2,2 -dimethoxy-1,2-diphenyl-1-one (trade name "omnirad 651", manufactured by IGM Resins Italia Srl) 0.05 parts by mass, and 1-hydroxy-cyclohexyl-phenyl-ketone (trade name "omnirad 184") , manufactured by IGM Resins Italia Srl) into a four-necked flask, and exposed to ultraviolet rays in a nitrogen atmosphere to partially photopolymerize, yielding a partially polymerized product (with a polymerization rate of 10%). Monomer syrup) was obtained. After adding 0.1 part by mass of an isocyanate compound (trade name "Takenate D-101A", manufactured by Mitsui Chemicals, Inc., solid content: 75% by mass) to 100 parts by mass of this partially polymerized product, they were uniformly mixed. A photopolymerizable composition was prepared.

The above photopolymerizable composition was applied onto the release-treated surface of a release liner (trade name "MRA50", manufactured by Mitsubishi Chemical Corporation, polyethylene terephthalate film with release treatment on one side, thickness 50 μm). After forming the resin composition layer, a release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the resin composition layer. Next, polymerization was performed by irradiating ultraviolet rays with an intensity of 5 mW/cm ² using a black light until the cumulative amount of light reached 3600 mJ/cm ² , thereby producing a non-light-diffusing layer 1 as an adhesive layer.

Manufacturing example 2
(Preparation of antireflection layer 1)
Butyl acrylate (BA) 67 parts by mass, cyclohexyl acrylate (CHA) 14 parts by mass, 4-hydroxybutyl acrylate (4HBA) 27 parts by mass, 2-hydroxyethyl acrylate (HEA) 9 parts by mass, 2,2 -dimethoxy-1,2-diphenyl-1-one (trade name "omnirad 651", manufactured by IGM Resins Italia Srl) 0.05 parts by mass, and 1-hydroxy-cyclohexyl-phenyl-ketone (trade name "omnirad 184") , manufactured by IGM Resins Italia Srl) into a four-necked flask, and exposed to ultraviolet rays in a nitrogen atmosphere to partially photopolymerize, yielding a partially polymerized product (with a polymerization rate of 10%). Monomer syrup) was obtained. To 100 parts by mass of this partially polymerized material, 0.1 part by mass of an isocyanate compound (product name "Takenate D-101A", manufactured by Mitsui Chemicals, solid content: 75% by mass) in terms of solid content, and a black pigment dispersion (trade name) After adding 9.2 parts by mass of 9050 Black (manufactured by Tokushiki Co., Ltd.), these were uniformly mixed to prepare a photopolymerizable composition.

The above photopolymerizable composition was applied onto the release-treated surface of a release liner (trade name "MRA50", manufactured by Mitsubishi Chemical Corporation, polyethylene terephthalate film with release treatment on one side, thickness 50 μm). After forming the resin composition layer, a release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the resin composition layer. Next, polymerization was performed by irradiating ultraviolet rays with an intensity of 5 mW/cm ² using a black light until the cumulative amount of light reached 3600 mJ/cm ² , thereby producing an antireflection layer 1 as an adhesive layer.

Manufacturing example 3
(Preparation of light diffusion layer 1)
Butyl acrylate (BA) 67 parts by mass, cyclohexyl acrylate (CHA) 14 parts by mass, 4-hydroxybutyl acrylate (4HBA) 27 parts by mass, 2-hydroxyethyl acrylate (HEA) 9 parts by mass, 2,2 -dimethoxy-1,2-diphenyl-1-one (trade name "omnirad 651", manufactured by IGM Resins Italia Srl) 0.05 parts by mass, and 1-hydroxy-cyclohexyl-phenyl-ketone (trade name "omnirad 184") , manufactured by IGM Resins Italia Srl) into a four-necked flask, and exposed to ultraviolet rays in a nitrogen atmosphere to partially photopolymerize, yielding a partially polymerized product (with a polymerization rate of 10%). Monomer syrup) was obtained. To 83 parts by mass of this partial polymer, 1.2 parts by mass of an isocyanate compound (product name "Takenate D-101A", manufactured by Mitsui Chemicals, Inc., solid content 75% by mass) in terms of solid content, and a silicone resin (product name " 30 parts by mass of Tospearl 145, manufactured by Momentive Performance Materials Japan, refractive index: 1.42, average particle size: 4.5 μm), 3-phenoxybenzyl acrylate (trade name: "Light Acrylate POB-A") , manufactured by Kyoeisha Kagaku Co., Ltd.) and 1 part by mass of "Omnirad 651" (trade name) were added, and these were uniformly mixed to prepare a photopolymerizable composition.

The above photopolymerizable composition was applied onto the release-treated surface of a release liner (trade name "MRA50", manufactured by Mitsubishi Chemical Corporation, polyethylene terephthalate film with release treatment on one side, thickness 50 μm). After forming the resin composition layer, a release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the resin composition layer. Next, polymerization was performed by irradiating ultraviolet rays with an intensity of 5 mW/cm ² using a black light until the cumulative amount of light reached 3600 mJ/cm ² , thereby producing a light-diffusing layer 1 as an adhesive layer.

Production example 4
(Preparation of light diffusion layer 2)
Butyl acrylate (BA) 67 parts by mass, cyclohexyl acrylate (CHA) 14 parts by mass, 4-hydroxybutyl acrylate (4HBA) 27 parts by mass, 2-hydroxyethyl acrylate (HEA) 9 parts by mass, 2,2 -dimethoxy-1,2-diphenyl-1-one (trade name "omnirad 651", manufactured by IGM Resins Italia Srl) 0.05 parts by mass, and 1-hydroxy-cyclohexyl-phenyl-ketone (trade name "omnirad 184") , manufactured by IGM Resins Italia Srl) into a four-necked flask, and exposed to ultraviolet rays in a nitrogen atmosphere to partially photopolymerize, yielding a partially polymerized product (with a polymerization rate of 10%). Monomer syrup) was obtained. To 83 parts by mass of this partial polymer, 0.08 parts by mass of an isocyanate compound (product name "Takenate D-101A", manufactured by Mitsui Chemicals, Inc., solid content 75% by mass) in terms of solid content, silicone resin (product name " 30 parts by mass of Tospearl 145, manufactured by Momentive Performance Materials Japan, refractive index: 1.42, average particle size: 4.5 μm), 3-phenoxybenzyl acrylate (trade name: "Light Acrylate POB-A") , manufactured by Kyoeisha Kagaku Co., Ltd.) and 1 part by mass of "Omnirad 651" (trade name) were added, and these were uniformly mixed to prepare a photopolymerizable composition.

The above photopolymerizable composition was applied onto the release-treated surface of a release liner (trade name "MRA50", manufactured by Mitsubishi Chemical Corporation, polyethylene terephthalate film with release treatment on one side, thickness 50 μm). After forming the resin composition layer, a release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the resin composition layer. Next, ultraviolet rays with an intensity of 5 mW/cm ² were irradiated with a black light until the cumulative amount of light reached 3600 mJ/cm ² to perform polymerization, thereby producing a light-diffusing layer 2 as an adhesive layer.

Manufacturing example 5
(Preparation of non-light diffusing layer 2)
Butyl acrylate (BA) 67 parts by mass, cyclohexyl acrylate (CHA) 14 parts by mass, 4-hydroxybutyl acrylate (4HBA) 27 parts by mass, 2-hydroxyethyl acrylate (HEA) 9 parts by mass, 2,2 -dimethoxy-1,2-diphenyl-1-one (trade name "omnirad 651", manufactured by IGM Resins Italia Srl) 0.05 parts by mass, and 1-hydroxy-cyclohexyl-phenyl-ketone (trade name "omnirad 184") , manufactured by IGM Resins Italia Srl) into a four-necked flask, and exposed to ultraviolet rays in a nitrogen atmosphere to partially photopolymerize, yielding a partially polymerized product (with a polymerization rate of 10%). Monomer syrup) was obtained. After adding 1.5 parts by mass of an isocyanate compound (trade name "Takenate D-101A", manufactured by Mitsui Chemicals, Inc., solid content 75% by mass) in terms of solid content to 100 parts by mass of this partially polymerized product, these were uniformly mixed. A photopolymerizable composition was prepared.

The above photopolymerizable composition was applied onto the release-treated surface of a release liner (trade name "MRA50", manufactured by Mitsubishi Chemical Corporation, polyethylene terephthalate film with release treatment on one side, thickness 50 μm). After forming the resin composition layer, a release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the resin composition layer. Next, polymerization was performed by irradiating ultraviolet rays with an intensity of 5 mW/cm ² using a black light until the cumulative amount of light reached 3600 mJ/cm ² , thereby producing a non-light-diffusing layer 2 as an adhesive layer.

Manufacturing example 6
(Preparation of light diffusion layer 3)
Butyl acrylate (BA) 67 parts by mass, cyclohexyl acrylate (CHA) 14 parts by mass, 4-hydroxybutyl acrylate (4HBA) 27 parts by mass, 2-hydroxyethyl acrylate (HEA) 9 parts by mass, 2,2 -dimethoxy-1,2-diphenyl-1-one (trade name "omnirad 651", manufactured by IGM Resins Italia Srl) 0.05 parts by mass, and 1-hydroxy-cyclohexyl-phenyl-ketone (trade name "omnirad 184") , manufactured by IGM Resins Italia Srl) into a four-necked flask, and exposed to ultraviolet rays in a nitrogen atmosphere to partially photopolymerize, yielding a partially polymerized product (with a polymerization rate of 10%). Monomer syrup) was obtained. To 100 parts by mass of this partial polymer, 0.1 part by mass of an isocyanate compound (trade name "Takenate D-101A", manufactured by Mitsui Chemicals, Inc., solid content 75 mass%) in terms of solid content and titanium oxide (trade name " After adding 3 parts by mass of "Tipure R706" (manufactured by DuPont, refractive index: about 2.5, average particle size: 0.36 μm), these were uniformly mixed to prepare a photopolymerizable composition.

The above photopolymerizable composition was applied onto the release-treated surface of a release liner (trade name "MRA50", manufactured by Mitsubishi Chemical Corporation, polyethylene terephthalate film with release treatment on one side, thickness 50 μm). After forming the resin composition layer, a release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the resin composition layer. Next, polymerization was performed by irradiating ultraviolet rays with an intensity of 5 mW/cm ² using a black light until the cumulative amount of light reached 3600 mJ/cm ² , thereby producing a light-diffusing layer 3 as an adhesive layer.

Manufacturing example 7
(Preparation of light diffusion layer 4)
Butyl acrylate (BA) 67 parts by mass, cyclohexyl acrylate (CHA) 14 parts by mass, 4-hydroxybutyl acrylate (4HBA) 27 parts by mass, 2-hydroxyethyl acrylate (HEA) 9 parts by mass, 2,2 -dimethoxy-1,2-diphenyl-1-one (trade name "omnirad 651", manufactured by IGM Resins Italia Srl) 0.05 parts by mass, and 1-hydroxy-cyclohexyl-phenyl-ketone (trade name "omnirad 184") , manufactured by IGM Resins Italia Srl) into a four-necked flask, and exposed to ultraviolet rays in a nitrogen atmosphere to partially photopolymerize, yielding a partially polymerized product (with a polymerization rate of 10%). Monomer syrup) was obtained. To 100 parts by mass of this partial polymer, 1.5 parts by mass of an isocyanate compound (trade name "Takenate D-101A", manufactured by Mitsui Chemicals, Inc., solid content 75 mass%) in terms of solid content and titanium oxide (trade name " After adding 3 parts by mass of "Tipure R706" (manufactured by DuPont, refractive index: about 2.5, average particle size: 0.36 μm), these were uniformly mixed to prepare a photopolymerizable composition.

The above photopolymerizable composition was applied onto the release-treated surface of a release liner (trade name "MRA50", manufactured by Mitsubishi Chemical Corporation, polyethylene terephthalate film with release treatment on one side, thickness 50 μm). After forming the resin composition layer, a release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) was laminated onto the resin composition layer. Next, polymerization was performed by irradiating ultraviolet rays with an intensity of 5 mW/cm ² using a black light until the cumulative amount of light reached 3600 mJ/cm ² , thereby producing a light-diffusing layer 4 as an adhesive layer.

Example 1
(Preparation of sheet for encapsulating optical semiconductor elements)
The release liner (trade name "MRF38") was peeled off from the light diffusing layer 1 obtained in Production Example 1 to expose the adhesive surface. The exposed surface of the light diffusion layer 1 is covered with a base film (trade name: "Diafoil T912E75 (UE80-)", manufactured by Mitsubishi Chemical Corporation, polyethylene terephthalate film with easy adhesion treatment on one side, thickness 75 μm). The third sealing layer consisting of the light diffusing layer 1 was formed on the base film.
Next, the release liner (trade name "MRA50") was peeled off from the surface of the third sealing layer (light diffusion layer 1) to expose the adhesive surface. The adhesive surface exposed by peeling off the release liner (trade name "MRF38") from the antireflection layer 1 obtained in Production Example 2 is bonded to the exposed surface of the third sealing layer. A second sealing layer consisting of antireflection layer 1 was formed on the substrate.
Next, the release liner (trade name "MRA50") was peeled off from the surface of the second sealing layer (antireflection layer 1) to expose the adhesive surface. The adhesive surface exposed by peeling off the release liner (trade name "MRF38") from the non-light-diffusing layer 1 obtained in Production Example 3 is bonded to the exposed surface of the second sealing layer to form the second sealing layer. A first sealing layer consisting of a non-light diffusing layer 1 was formed thereon.
Then, they were pasted together using a hand roller at room temperature (23° C.) to avoid air bubbles, and left for two days in the dark. In this way, a sheet for encapsulating an optical semiconductor element consisting of [release liner/non-light diffusing layer 1/antireflection layer 1/light diffusing layer 1/base film] was obtained.

Examples 2-3, Comparative Examples 1-5
(Preparation of sheet for encapsulating optical semiconductor elements)
A sheet for encapsulating an optical semiconductor element was obtained in the same manner as in Example 1 except that the layers shown in the table were formed as the first sealing layer, the second sealing layer, and the third sealing layer.

<Evaluation>
The following evaluations were made for the sheets for encapsulating optical semiconductor elements obtained in the Examples and Comparative Examples, and the sheets in which an anti-glare treatment layer as a functional layer was provided on the surface of the base film of these sheets for encapsulating optical semiconductor elements. I did it. The results are shown in the table. In the table, "whole sheet (without anti-glare treatment layer)" indicates the sheet for encapsulating optical semiconductor elements obtained in Examples and Comparative Examples, and "whole sheet (with anti-glare treatment layer)" indicates the surface of the base film. 2 shows a sheet for encapsulating optical semiconductor devices that has been subjected to anti-glare treatment.

In addition, in each of the Examples and Comparative Examples, the sheet for encapsulating an optical semiconductor element provided with an anti-glare treatment layer was used as a base film in advance on the side opposite to the side to which the third sealing layer and the third sealing layer of the base film were bonded. It was produced in the same manner as in each of the Examples and Comparative Examples except that an anti-glare treatment layer was used. A base film provided with an anti-glare treated layer was produced as follows.

(Method for producing base film with anti-glare treatment layer)
The main components of the resin contained in the anti-glare treatment layer forming material are 40 parts by mass of an ultraviolet curable polyfunctional acrylate resin (trade name "UA-53H", manufactured by Shin Nakamura Chemical Co., Ltd.) and pentaerythritol triacrylate. 60 parts by mass of polyfunctional acrylate (trade name "Viscoat #300" manufactured by Osaka Organic Chemical Industry Co., Ltd.) was prepared. Per 100 parts by mass of the total resin solid content of the above resin, 7.0 parts by mass of acrylic and styrene copolymer particles (trade name "Techpolymer SSX-103DXE", manufactured by Sekisui Plastics Co., Ltd.) are used as anti-glare treatment layer forming particles. 3 parts by mass of silicone resin (trade name "TOSPEARL130", manufactured by Momentive Performance Materials Japan), 2 parts by mass of synthetic smectite (trade name "Smecton SAN", manufactured by Kunimine Industries Co., Ltd.) as a thixotropy imparting agent. 5 parts by mass, 3 parts by mass of a photopolymerization initiator (trade name "OMNIRAD907", manufactured by BASF Corporation), and 0.15 parts by mass of a leveling agent (trade name "GRANDIC PC4100", manufactured by DIC Corporation) were mixed. This mixture was diluted with a toluene/cyclopentanone mixed solvent (mass ratio 80/20) so that the solid content concentration was 40% by mass to prepare an anti-glare treatment layer forming material (coating liquid).

A transparent plastic film substrate (trade name "KC4UY", TAC, manufactured by Konica Minolta, Inc.) was prepared as a translucent substrate. A coating film was formed on one side of the transparent plastic film substrate using the anti-glare treatment layer forming material (coating liquid) using a bar coater. The transparent plastic film base material on which this coating film was formed was then transported to a drying process. In the drying step, the coating film was dried by heating at 80° C. for 1 minute. Thereafter, the coating film is cured by irradiating ultraviolet rays with a cumulative light intensity of 300 mJ/cm ² using a high-pressure mercury lamp to form an anti-glare layer with a thickness of 8.5 μm, resulting in an anti-glare film with a haze of 25%. (Base film with anti-glare treatment layer) was obtained.

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

(2) Haze value (each layer)
Measure the total light transmittance and diffuse transmittance of the measurement sample prepared to measure the total light transmittance in (1) above using a haze meter (equipment name "HM-150", manufactured by Murakami Color Research Institute Co., Ltd.) did. Then, the haze value of the measurement sample was determined using the formula "diffuse transmittance/total light transmittance x 100" and was determined as the initial haze value.

(3) Total light transmittance (sheet for encapsulating optical semiconductor elements)
A measurement sample was prepared by peeling off the release liner from the optical semiconductor element sealing sheet and pasting the exposed adhesive layer surface onto a glass plate (slide glass, product number "S-9112", manufactured by Matsunami Glass Industries Co., Ltd.). The total light transmittance of the above measurement sample was measured using a haze meter (device name: "HM-150", manufactured by Murakami Color Research Institute Co., Ltd.). Measurement light was applied from the base film side (first surface side) to perform measurements.

(4) Haze value (sheet for optical semiconductor device sealing)
Measure the total light transmittance and diffuse transmittance of the measurement sample prepared to measure the total light transmittance (3) above using a haze meter (equipment name "HM-150", manufactured by Murakami Color Research Institute Co., Ltd.) did. Then, the haze value of the measurement sample was determined using the formula "diffuse transmittance/total light transmittance x 100" and was defined as the haze value. Measurement light was applied from the base film side (first surface side) to perform measurements.

(5) L ^* a ^* b ^* (SCE) (with release liner)
The optical semiconductor element sealing sheet was placed on the flat surface of a blackboard (made of acrylic, black, size: 45 mm x 50 mm x 1 mm, manufactured by Mizunoue Disaster Bogu Co., Ltd.) with the base film side facing up. Then, L ^* (SCE), a ^* (SCE), and b ^* (SCE) were measured from the base film side (first surface side) using a spectrophotometer (product name "CM-26dG", manufactured by Konica Minolta, Inc.). ) were measured. Further, the sheet for encapsulating an optical semiconductor element was placed on a flat surface of a blackboard with the release liner surface facing up. Then, L ^* (SCE), a ^* (SCE), and b ^* (SCE) were measured from the release liner surface side (second surface side) using a spectrophotometer (product name "CM-26dG", manufactured by Konica Minolta, Inc.). ) were measured. The measurement area of the colorimeter was placed in the center of the sample to be measured, and measurements were made under the following conditions. Furthermore, before performing measurements with the spectrophotometer, zero point calibration, white calibration, and GROSS calibration were performed according to the manufacturer's manual. Note that the release liner bonded to the sealing portion has a haze value of 10.2% and a total light transmittance of 91.2%.
<Measurement conditions>
Measurement method: Color & Gloss Geometry: DI: 8°, DE: 8°
Specular reflection light processing: SCI+SCE
Observation light source: D65
Observation conditions: 10° field of view Measurement diameter: MAV (8mm)
UV conditions: 100%Full
Automatic average measurement: 3 times Zero calibration skip: Enabled

(6) L ^* a ^* b ^* (SCE) (without release liner)
The release liner attached to the sealing part was peeled off from the optical semiconductor device sealing sheet, and the sealing part was exposed on a blackboard (made of acrylic, black, size: 45 mm x 50 mm x 1 mm, manufactured by Mizunoue Disaster Bogu Co., Ltd.) were pasted together, and pressure was applied once on each side of the base film using a hand roller to prevent air bubbles from entering, so that the sealed portion was brought into close contact with the blackboard. Then, it was placed on the flat surface of a blackboard with the base film side facing up. Then, L ^* (SCE), a ^* (SCE), and b ^* (SCE) were measured from the base film side (first surface side) using a spectrophotometer (product name "CM-26dG", manufactured by Konica Minolta, Inc.). ) were measured. Further, the release liner bonded to the sealing part was peeled off from the optical semiconductor element sealing sheet, and the sheet was left standing on the flat surface of a blackboard with the exposed sealing part facing up. Then, L ^* (SCE), a ^* (SCE), and b ^* ( SCE) was measured. The measurement area of the colorimeter was placed in the center of the measurement sample, and the measurement was conducted under the same conditions as in the evaluation (5) above. Furthermore, before performing measurements with the spectrophotometer, zero point calibration, white calibration, and GROSS calibration were performed according to the manufacturer's manual.

(7) Light diffusion effect confirmation test Peel off the release liner of the optical semiconductor element sealing sheet, and use a hand roller to remove the glass plate (slide glass, product number "S-9112", Matsunami Glass Industries Co., Ltd.) to prevent air bubbles from entering. (manufactured by the company, 76 mm x 52 mm x 1.0 to 1.2 mm). After bonding, the panels were left standing at 25° C. for 30 minutes in the dark. The pasted optical semiconductor element sealing sheet was appropriately cut to the same size as the glass plate, and a measurement sample was prepared. An LED lamp (product name ``LK-3PG'', manufactured by EK Japan Co., Ltd.) was installed at the top of the screen so that the height was 2.4 cm. The glass plate side of the obtained measurement sample was brought into close contact with the LED lamp. A battery box (trade name "AP-180", manufactured by EK Japan Co., Ltd.) was connected to the LED lamp, the LED lamp was turned on, and the diameter of the circular image projected on the screen was measured. When measured using only the glass plate without the optical semiconductor element sealing sheet, the diameter of the light reflected on the screen was 16 mm. When the light diameter was 20 mm or more when measured through the optical semiconductor element sealing sheet, it was determined that there was a light diffusion effect.

(8) Judgment Based on the results of the above evaluations (3) and (6) (with anti-glare treatment layer), the light extraction efficiency and light diffusion effect were judged based on the following criteria. As a comprehensive judgment, for the optical semiconductor encapsulation sheet provided with an anti-glare treatment layer, if the light extraction efficiency is ○ or △ and the light diffusion effect is ○, it is ○, and if even one is ○, it is rated ×. did.
Light extraction efficiency: ○ when the total light transmittance is 3% or more, △ when the total light transmittance is 2% or more and less than 3%, and × when the total light transmittance is less than 2%.
Light diffusion effect: A case of 20 mm or more is marked as ○, a case of less than 20 mm is marked as ×.

As shown in Table 1, the optical semiconductor element sealing sheet (Example) of the present invention was evaluated to be excellent in light extraction efficiency and light diffusivity. On the other hand, as shown in Table 2, when the difference in L ^* (SCE) was large, the light extraction efficiency was evaluated to be poor (Comparative Examples 1 and 2). In particular, in Comparative Example 2, the optical semiconductor element sealing sheet without an anti-glare layer had excellent light diffusivity, but the sheet with an anti-glare layer had poor light diffusivity. Moreover, in the case of not having a light-diffusing layer, the light-diffusing property was poor (Comparative Example 3). Further, when the difference in L ^* (SCE) was large, there were cases where the light diffusivity was evaluated as being inferior (Comparative Examples 4 and 5).

1 Sheet for optical semiconductor element sealing 2 Sealing part 21 First sealing layer 22 Second sealing layer 23 Third sealing layer 3 Release liner 4 Base material part 41 Base film 42 Functional layer 5 Substrate 6 Optical semiconductor element 10,20 Optical semiconductor device

Claims (8)

A sheet for sealing one or more optical semiconductor elements arranged on a substrate, the sheet comprising:
The sheet includes a sealing portion having a light diffusion layer and an antireflection layer,
The sealing section includes a first sealing layer in contact with the optical semiconductor element, a second sealing layer laminated on the first sealing layer, and a third sealing layer laminated on the second sealing layer. A stop layer is provided,
Among the first sealing layer, the second sealing layer, and the third sealing layer, at least one layer is the antireflection layer, and at least one other layer is the light diffusion layer,
The light diffusing layer includes a light diffusing agent made of silicone resin,
The antireflection layer has adhesiveness and/or adhesiveness,
A functional layer may be provided on the surface of the sheet opposite to the surface that contacts the optical semiconductor element,
If the sheet does not include the functional layer, separately, in a state where the functional layer is laminated on the surface of the sheet opposite to the surface that contacts the optical semiconductor element, a field of view of 10° from the functional layer side, a light source L ^* (SCE), a ^* (SCE), b ^* (SCE) in L ^* a ^* b ^* (SCE) when measured under the conditions of D65 are respectively L ^* ₁ , a ^* ₁ , b ^* ₁ , L ^* (SCE), a ^* (SCE), and ^{b *} (SCE) in L * a ^* b ^* (SCE) when measured under the conditions of 10° field of view from the sheet side and light source D65 are L ^* ₂ , When a ^* ₂ and b ^* ₂ , the above L ^* ₁ , a ^* ₁ , b ^* ₁ , L ^* ₂ , a ^* ₂ , and b ^* ₂ are values that satisfy the following formulas (1) to (3), respectively. and
The sheet for encapsulating an optical semiconductor device, wherein the functional layer includes at least one of an anti-glare treated layer, an anti-reflection treated layer, and a hard coat treated layer.
-5<L ^* ₁ -L ^* ₂ <5 (1)
-5<a ^* ₁ -a ^* ₂ <5 (2)
-5<b ^* ₁ -b ^* ₂ <5 (3) The sheet for encapsulating an optical semiconductor element according to claim 1, wherein the sheet has a total light transmittance of 2 to 30% measured from the functional layer side in a state where the functional layer is laminated on one side of the sheet. 3. The sealing part includes, in this order, the light diffusion layer, the antireflection layer, and the light diffusion layer or a colorless transparent layer that is not intended to exhibit a light diffusion function. sheet for encapsulating optical semiconductor devices. The sheet for encapsulating an optical semiconductor device according to any one of claims 1 to 3, wherein the light diffusing agent has a refractive index of 1.4 to 1.7. The sheet for encapsulating an optical semiconductor device according to any one of claims 1 to 4 , wherein the functional layer includes a surface treatment layer. The sheet for encapsulating an optical semiconductor element according to any one of claims 1 to 5 , comprising a substrate, an optical semiconductor element disposed on the substrate, and the optical semiconductor element sealed by the sealing part. An optical semiconductor device comprising: The optical semiconductor device according to claim 6 , which is a self-luminous display device. An image display device comprising the self-luminous display device according to claim 7 .

Images