JP2018041857A - Optical semiconductor element coated with phosphor layer and light diffusion layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical semiconductor element coated with a phosphor layer and a light diffusion layer, excellent in color uniformity in an angle direction.SOLUTION: An optical semiconductor element 1 coated with a phosphor layer and a light diffusion layer includes: an optical semiconductor element 2 whose top face 21 and side face 23 emit light; a phosphor layer 3 arranged on the top face 21 and the side face 23 of the optical semiconductor element 2; and a light diffusion layer 4 arranged on the top face and the side face of the phosphor layer 3 and containing light diffusion particles and a resin. The absolute value of a refractive index difference between the light diffusion particles and the resin is 0.04 or more and 0.20 or less. The light diffusion particles of 0.0010 cmor more and 0.0180 cmor less per exist per 1 cmin a plan view of an upper part 41 of the light diffusion layer, and also the light diffusion particles of 0.0010 cmor more and 0.0180 cmor less exist per 1 cmin a side view of a side portion 42 of the light diffusion layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a phosphor layer light diffusion layer-coated optical semiconductor element.

  Conventionally, a white light semiconductor device is known as a light emitting device capable of emitting high-energy light. The white light semiconductor device includes, for example, a diode substrate that supplies electric power to the LED, an LED (light emitting diode) that is mounted thereon and emits blue light, and a phosphor that can convert blue light into yellow light and covers the LED A layer, a sealing layer that seals the LED, and a reflective layer that is provided around the LED and reflects light forward are provided. The white light semiconductor device is a high-energy white by mixing blue light emitted from the LED and transmitted through the phosphor layer and the sealing layer with yellow light obtained by converting part of the blue light in the phosphor layer. Emits light.

  As such an optical semiconductor light emitting device, for example, an optical semiconductor light emitting device disclosed in Patent Document 1 has been proposed. The optical semiconductor light emitting device of Patent Document 1 has a semiconductor multilayer film including a light emitting layer and a base substrate, and the phosphor film has side and upper surfaces (surfaces opposite to the base substrate) of the optical semiconductor multilayer film. It is formed to cover.

  According to the optical semiconductor light-emitting device of Patent Document 1, the yield of the optical semiconductor light-emitting device can be improved without causing an increase in size.

JP 2005-252222 A

  However, in the optical semiconductor light emitting device of Patent Document 1, there is a problem that the light emitted from the semiconductor multilayer film through the phosphor film becomes non-uniform depending on the radiation angle. Specifically, the light emitted in the oblique direction is more yellowish than the light emitted in the front direction (upper side). As a result, color unevenness occurs depending on the emitted angle.

  The objective of this invention is providing the fluorescent substance layer light-diffusion layer coating | cover optical semiconductor element which is excellent in the color uniformity in an angle direction.

The present invention [1] includes an optical semiconductor element that emits light from an upper surface and a side surface, a phosphor layer that is disposed on the upper surface and the side surface of the optical semiconductor element, and a light diffusion particle that is disposed on the upper surface and the side surface of the phosphor layer. And a light diffusing layer containing a resin, and an absolute value of a difference in refractive index between the light diffusing particles and the resin is 0.04 or more and 0.20 or less, and is disposed on an upper surface of the optical semiconductor element. The light diffusing particles are present in the range of 0.0010 cm ³ or more and 0.0180 cm ³ or less per 1 cm ² in plan view of the light diffusing layer, and per 1 cm ^{2 in} side view of the light diffusing layer disposed on the side surface of the optical semiconductor element. The light diffusing particles include a phosphor layer light diffusing layer-coated optical semiconductor element in which 0.0010 cm ³ or more and 0.0180 cm ³ or less are present.

  In the present invention [2], the ratio (L1 / L2) of the vertical length L1 at the upper part of the phosphor layer to the orthogonal length L2 at the side part of the phosphor layer is 1.0 or more. The phosphor layer light diffusing layer-coated optical semiconductor element according to [1], which is 0 or less, is included.

  In the present invention [3], the ratio (L3 / L4) of the vertical length L3 in the upper part of the light diffusion layer and the orthogonal length L4 in the side part of the light diffusion layer is 0.8 or more. The phosphor layer light diffusion layer-coated optical semiconductor element according to [1] or [2], which is 2 or less.

  According to the phosphor layer light diffusion layer-coated optical semiconductor element of the present invention, the color uniformity in the angular direction is excellent.

1A to 1B show a first embodiment of a phosphor layer light diffusion layer-coated optical semiconductor element of the present invention, FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view taken along line AA in FIG. 1A. . 2A to 2G are process diagrams of the manufacturing method of the phosphor layer light diffusion layer-coated optical semiconductor element of FIG. 1, FIG. 2A is a temporary fixing sheet preparation process, FIG. 2B is a temporary fixing process, and FIG. 2D shows a phosphor layer removing process, FIG. 2E shows a light diffusion layer forming process, FIG. 2F shows a cutting process, and FIG. 2G shows a mounting process.

  In FIG. 1B, the vertical direction of the paper is the vertical direction (first direction, thickness direction), the upper side of the paper is the upper side (one side in the first direction, the one side in the thickness direction), and the lower side of the paper is the lower side (the other side in the first direction). , The other side in the thickness direction). The left-right direction on the paper surface is the left-right direction (second direction orthogonal to the first direction, an example of the orthogonal direction to the up-down direction), the left side of the paper is the left side (second side in the second direction), and the right side of the paper is the right side (the other in the second direction). Side). The paper thickness direction is the front-rear direction (the third direction orthogonal to the first direction and the second direction, an example of the orthogonal direction to the vertical direction), the front side of the paper is the front side (one side in the third direction), and the back side of the paper is the rear side (The other side in the third direction). Specifically, it conforms to the direction arrow in each figure.

<First Embodiment>
1A to 1B, a first embodiment of a phosphor layer light diffusion layer-coated optical semiconductor element 1 (hereinafter also simply referred to as a two-layer coated element) of the present invention will be described.

  The double-layer covering element 1 does not include an optical semiconductor device (light emitting device, symbol 5 shown in FIG. 2G), that is, includes a substrate (electrode substrate, symbol 6 shown in FIG. 2G) provided in the optical semiconductor device. Not. Specifically, the two-layer covering element 1 includes an optical semiconductor element 2, a phosphor layer 3, and a light diffusion layer 4. The two-layer covering element 1 is preferably composed of an optical semiconductor element 2, a phosphor layer 3, and a light diffusion layer 4. That is, the two-layer covering element 1 is configured so as not to be electrically connected to the electrode provided on the substrate of the optical semiconductor device. The double-layer covering element 1 is a part of an optical semiconductor device, that is, a part for producing the optical semiconductor device, and is a device that can be distributed and used industrially.

  As shown in FIGS. 1A to 1B, the two-layer covering element 1 includes an optical semiconductor element 2, a phosphor layer 3, and a light diffusion layer 4.

  The optical semiconductor element 2 is, for example, an LED (light emitting diode element) or LD (semiconductor laser element) that converts electrical energy into optical energy. Preferably, the optical semiconductor element 2 is a blue LED that emits blue light. On the other hand, the optical semiconductor element 2 does not include a rectifier (semiconductor element) such as a transistor having a technical field different from that of the optical semiconductor element 2.

  The optical semiconductor element 2 has a substantially flat plate shape along the left-right direction and the front-rear direction. The optical semiconductor element 2 has a substantially rectangular shape in plan view (preferably, a substantially square shape in plan view). The optical semiconductor element 2 includes an upper surface 21, a lower surface 22, and a side surface 23.

  The upper surface 21 is a light emitting surface that emits light upward, and has a flat shape. A phosphor layer 3 (described later) is provided on the upper surface 21.

  The lower surface 22 is a surface on which the electrode 24 is formed, and is disposed opposite to the upper surface 21 with a gap therebetween. A plurality of (two) electrodes 24 are provided, and have a shape that slightly protrudes from the lower surface 22 toward the lower side.

  The side surface 23 is a light emitting surface that emits light, and connects the peripheral edge of the upper surface 21 and the peripheral edge of the lower surface 22. The side surface 23 includes four surfaces including a front surface 23a, a rear surface 23b, a left surface 23c, and a right surface 23d. That is, light is emitted from the front surface 23a, the rear surface 23b, the left surface 23c, and the right surface 23d.

  The optical semiconductor element 2 emits light from at least five surfaces (that is, the upper surface 21 and the side surface 23) in five directions (that is, the upper side, the front side, the rear side, the left side, and the right side).

  The dimensions of the optical semiconductor element 2 are appropriately set. Specifically, the thickness (length in the vertical direction) is, for example, 0.1 μm or more, preferably 10 μm or more, more preferably 100 μm or more, For example, it is 2000 micrometers or less, Preferably, it is 1500 micrometers or less, More preferably, it is 500 micrometers or less. The length in the left-right direction and / or the front-rear direction of the optical semiconductor element 2 is, for example, 200 μm or more, preferably 500 μm or more, and for example, 3000 μm or less, preferably 2000 μm or less.

  The phosphor layer 3 is arranged on the upper side and the side of the optical semiconductor element 2 so as to cover the upper surface 21 and the side surface 23 (front surface 23a, rear surface 23b, left surface 23c, and right surface 23d) of the optical semiconductor element 2. That is, the phosphor layer 3 is arranged on the upper side and the periphery of the optical semiconductor element 2 so as to completely cover five surfaces other than the lower surface of the optical semiconductor element 2. The phosphor layer 3 has a substantially rectangular shape in plan view (preferably, a substantially square shape in plan view), and is formed so as to include the optical semiconductor element 2 when projected in the vertical direction. The phosphor layer 3 includes a phosphor layer upper part 31 disposed on the upper side of the optical semiconductor element 2 and a phosphor layer side part 32 disposed on the side of the optical semiconductor element 2.

  The phosphor layer upper part 31 has a substantially flat plate shape along the left-right direction and the front-rear direction, and has the outer shape of the phosphor layer 3 in plan view. Specifically, the central portion of the lower surface of the phosphor layer upper portion 31 is in contact with the entire upper surface 21 of the optical semiconductor element 2, and the outer peripheral portion of the lower surface of the phosphor layer upper portion 31 is in contact with the upper surface of the phosphor layer side portion 32. It is continuous continuously.

  The phosphor layer side portion 32 has a substantially rectangular frame shape in plan view extending in the vertical direction. The phosphor layer side portion 32 is disposed around the optical semiconductor element 2 so as to be in contact with and cover the side surface 23 of the optical semiconductor element 2. That is, the inner peripheral surface of the phosphor layer side portion 32 is in contact with the entire side surface 23 of the optical semiconductor element 2. The phosphor layer side portion 32 includes a phosphor layer front portion 32a, a phosphor layer rear portion 32b, a phosphor layer left portion 32c, and a phosphor layer right portion 32d.

  The vertical length L1 (thickness) of the phosphor layer upper portion 31 of the phosphor layer 3 is, for example, 10 μm or more, preferably 50 μm or more, more preferably 100 μm or more, and for example, 500 μm or less, preferably 400 μm or less, more preferably 300 μm or less.

  The length L2 in the orthogonal direction of the phosphor layer side portion 32 of the phosphor layer 3 (the length in the front-rear direction of the phosphor layer front portion 32a and the phosphor layer rear portion 32b, the phosphor layer left portion 32c, and the phosphor layer right portion 32d) The length in the left-right direction is, for example, 10 μm or more, preferably 50 μm or more, more preferably 70 μm or more, and for example, 1000 μm or less, preferably 500 μm or less, more preferably 200 μm or less.

  The ratio between L1 and L2 (L1 / L2) is, for example, 0.5 or more, preferably 1.0 or more, more preferably 1.5 or more, and for example, 5.0 or less. Preferably, it is 3.4 or less, more preferably 3.0 or less. By setting the ratio (L1 / L2) within the above range, color conversion on the upper side and side can be made uniform, and color uniformity in the angle direction can be made even better.

  The phosphor layer 3 is formed from, for example, a phosphor composition containing a phosphor and a resin.

  The phosphor converts the wavelength of the light emitted from the optical semiconductor element 2. Examples of the phosphor include a yellow phosphor that can convert blue light into yellow light, and a red phosphor that can convert blue light into red light.

Examples of the yellow phosphor include silicate phosphors such as (Ba, Sr, Ca) ₂ SiO ₄ ; Eu, (Sr, Ba) ₂ SiO ₄ : Eu (barium orthosilicate (BOS)), for example, Y ₃ Al Garnet-type phosphors having a garnet-type crystal structure such as ₅ O ₁₂ : Ce (YAG (yttrium, aluminum, garnet): Ce), Tb ₃ Al ₃ O ₁₂ : Ce (TAG (terbium, aluminum, garnet): Ce) Examples thereof include oxynitride phosphors such as Ca-α-SiAlON.

Examples of the red phosphor include nitride phosphors such as CaAlSiN ₃ : Eu and CaSiN ₂ : Eu.

  The phosphors can be used alone or in combination of two or more.

  Examples of the shape of the phosphor include a spherical shape, a plate shape, and a needle shape.

  The average value of the maximum length of the phosphor (in the case of a sphere, the average particle diameter) is, for example, 0.1 μm or more, preferably 1 μm or more, and for example, 200 μm or less, preferably 100 μm or less. It is.

  The content rate of a fluorescent substance is 1 mass% or more with respect to a fluorescent composition, Preferably, it is 10 mass% or more, for example, is 50 mass% or less, Preferably, it is 40 mass% or less.

  The resin is a matrix in which the phosphor is uniformly dispersed in the phosphor composition, and examples of the resin include resins described later in the light diffusion composition. Preferably, a curable resin is used, more preferably a thermosetting resin that can be a B-stage, more preferably a thermoplastic / thermosetting silicone resin, and particularly preferably phenyl. -Based silicone resin compositions.

  The content ratio of the resin is, for example, 10% by mass or more, preferably 20% by mass or more, and, for example, 90% by mass or less, preferably 70% by mass or less, more preferably, with respect to the fluorescent composition. 45 mass% or less.

  The fluorescent composition may further contain particles in addition to the above components.

  Examples of such particles include fillers and thixotropic particles.

  As a filler, the thing similar to what is later mentioned by a light-diffusion composition is mentioned, Preferably, a glass particle is mentioned.

  When the filler is contained, the content ratio of the filler is, for example, 10% by mass or more, preferably 20% by mass or more, and, for example, 50% by mass or less, preferably, with respect to the fluorescent composition. It is 45 mass% or less.

  Examples of the thixotropy-imparting particles include those described later for the light diffusing composition, and preferably fumed silica.

  When the thixotropic particles are contained, the content ratio of the thixotropic particles is, for example, 0.01% by mass or more, preferably 0.1% by mass or more with respect to the fluorescent composition. It is 10 mass% or less, Preferably, it is 5 mass% or less.

  The light diffusion layer 4 is a diffusion layer that diffuses light emitted from the optical semiconductor element 2 and wavelength-converted by the phosphor layer 3. The light diffusion layer 4 covers the phosphor layer upper part 31 and the phosphor layer side part 32 (phosphor layer front part 32a, phosphor layer rear part 32b, phosphor layer left part 32c, and phosphor layer right part 32d). The phosphor layer 3 is disposed on the upper side and the side. The light diffusion layer 4 has a substantially rectangular shape in plan view (preferably, a substantially square shape in plan view), and is formed so as to include the phosphor layer 3 when projected in the vertical direction.

  The light diffusion layer 4 has a light transmittance of 100 μm when irradiated with light having a wavelength of 450 nm, for example, exceeding 30%, preferably 40% or more, and for example, 80% or less, preferably 70% or less.

  The light diffusion layer 4 includes a light diffusion layer upper portion 41 disposed on the upper side of the phosphor layer 3 and a light diffusion layer side portion 42 disposed on the side of the phosphor layer 3.

  The light diffusion layer upper portion 41 has a substantially flat plate shape along the left-right direction and the front-rear direction, and has the outer shape of the light diffusion layer 4 in plan view. Specifically, the central portion of the lower surface of the light diffusion layer upper portion 41 is in contact with the entire surface of the phosphor layer upper portion 31, and the outer peripheral portion of the lower surface of the light diffusion layer upper portion 41 is integrated with the upper surface of the light diffusion layer side portion 42. It is continuous.

  The light diffusion layer side portion 42 has a substantially rectangular frame shape in plan view extending in the vertical direction. The light diffusion layer side portion 42 is disposed around the phosphor layer 3 so as to be in contact with and cover the side surface of the phosphor layer 3. That is, the inner peripheral surface of the light diffusion layer side portion 42 is in contact with the entire side surface of the phosphor layer upper portion 31 and the entire side surface of the phosphor layer side portion 32. The light diffusion layer side portion 42 includes a light diffusion layer front portion 42a, a light diffusion layer rear portion 42b, a light diffusion layer left portion 42c, and a light diffusion layer right portion 42d.

  The vertical length L3 (thickness) of the light diffusion layer upper portion 41 is, for example, 10 μm or more, preferably 50 μm or more, more preferably 100 μm or more, and, for example, 1000 μm or less, preferably 500 μm or less. Preferably, it is 300 μm or less.

  The length L4 in the orthogonal direction of the light diffusion layer side portion 42 (the length in the front-rear direction of the light diffusion layer front portion 42a and the light diffusion layer rear portion 42b, the length in the left-right direction of the light diffusion layer left portion 42c and the light diffusion layer right portion 42d) ) Is, for example, 10 μm or more, preferably 50 μm or more, more preferably 150 μm or more, and for example, 2000 μm or less, preferably 800 μm or less, more preferably 300 μm or less.

  The ratio of L3 to L4 (L3 / L4) is, for example, 0.1 or more, preferably 0.5 or more, more preferably 0.8 or more, and for example, 10 or less, preferably 7.0 or less, more preferably 2.0 or less, and still more preferably 1.2 or less. By setting the ratio (L1 / L2) within the above range, the light diffusion on the upper side and the side can be made more uniform, and the color uniformity in the angular direction can be further improved.

  The light diffusion layer 4 is formed of, for example, a light diffusion composition containing light diffusion particles and a resin.

  The light diffusing particles are transparent particles that diffuse light and include particles having a high refractive index difference from the resin.

  Specific examples include light diffusing inorganic particles and light diffusing organic particles.

  Examples of the light diffusing inorganic particles include silica particles and composite inorganic oxide particles.

  The composite inorganic oxide particles are preferably glass particles, specifically containing silica or silica and boron oxide as main components, and also containing aluminum oxide, calcium oxide, zinc oxide, strontium oxide, Magnesium oxide, zirconium oxide, barium oxide, antimony oxide and the like are contained as accessory components. The content ratio of the main component in the composite inorganic oxide particles is, for example, 40% by mass or more, preferably 50% by mass or more, and for example, 90% by mass or less, preferably with respect to the composite inorganic oxide particles. 80% by mass or less. The content ratio of the subcomponent is the remainder of the content ratio of the main component described above.

  Examples of the light diffusing organic particles include acrylic resin particles, styrene resins, acrylic-styrene resin particles, silicone resin particles, polycarbonate resin particles, benzoguanamine resin particles, polyolefin resin particles, polyester resin particles, Examples include polyamide resin particles and polyimide resin particles.

  The light diffusing organic particles preferably include acrylic resin and silicone resin particles, and more preferably include silicone resin particles.

  The light diffusing particles are preferably light diffusing inorganic particles, more preferably silica particles and glass particles, from the viewpoint of light diffusibility and durability.

  The refractive index of the light diffusing particles is, for example, 1.40 or more, preferably 1.45 or more, and for example, 1.60 or less, preferably 1.55 or less. The refractive index is measured by, for example, an Abbe refractometer.

  The absolute value of the refractive index difference between the light diffusing particles and the resin (described later) is 0.04 or more and 0.20 or less. Preferably, it is 0.08 or more, more preferably 0.11 or more, and preferably 0.18 or less, more preferably 0.15 or less. By setting the refractive index difference within the above range, the light incident on the light diffusion layer 4 can be diffused by the light diffusion particles with a good balance. Therefore, the color uniformity in the angular direction can be improved with respect to the light emitted from the light diffusion layer 4 to the outside.

  The average particle diameter of the light diffusing particles is, for example, 1.0 μm or more, preferably 3.0 μm or more, more preferably 5.0 μm or more, and for example, 100 μm or less, preferably 50 μm or less. In the present invention, the average particle size is obtained as a volume-based D50 value by a particle size distribution measuring device.

  The mass ratio of the light diffusing particles is, for example, 1% by mass or more, preferably 2% by mass or more, more preferably 5% by mass or more, and, for example, 45% by mass or less with respect to the light diffusing composition. The amount is preferably 30% by mass or less, more preferably 10% by mass or less. The volume ratio of the light diffusing particles is, for example, 1% by volume or more, preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 18% by volume or more with respect to the light diffusion composition. Moreover, it is 50 volume% or less, for example, Preferably, it is 40 volume% or less.

  Examples of the resin include a curable resin and a thermoplastic resin. Preferably, a curable resin is used. Examples of the curable resin include thermosetting resins such as a two-stage reaction curable resin and a one-stage reaction curable resin.

  The two-stage reaction curable resin has two reaction mechanisms. In the first stage reaction, the A stage is changed to the B stage (semi-cured), and then the second stage reaction is performed from the B stage to the C stage. It can be staged (completely cured). That is, the two-stage reaction curable resin is a thermosetting resin that can be a B stage under appropriate heating conditions. The B stage is a state between the A stage in which the thermosetting resin is in a liquid state and the fully cured C stage, and the curing and gelation proceed slightly, and the compression elastic modulus is the elastic modulus of the C stage. A smaller semi-solid or solid state.

  The one-stage reaction curable resin has one reaction mechanism, and can be changed from the A stage to the C stage (completely cured) by the first stage reaction. Such a one-stage reaction curable resin can be changed from the A stage to the B stage in the middle of the first stage reaction, and the subsequent stage heating causes the first stage reaction to proceed. It includes a thermosetting resin that can be resumed to be C-staged (completely cured) from the B-stage. That is, such a thermosetting resin is a one-stage reaction curable resin that can be a B-stage. In addition, the one-stage reaction curable resin cannot be controlled to stop in the middle of the one-stage reaction, that is, cannot become the B stage, and is changed from the A stage to the C stage (fully cured) at a time. Also includes thermosetting resin. That is, such a thermosetting resin is a one-stage reaction curable resin that cannot be a B-stage.

  Preferably, the thermosetting resin includes a thermosetting resin (two-stage reaction curable resin and one-stage reaction curable resin) that can be a B-stage.

  The thermosetting resin that can be the B stage is preferably a silicone resin or an epoxy resin, and more preferably a silicone resin.

  In addition, as a silicone resin that can be a B stage, for example, a silicone resin that has both thermoplasticity and thermosetting properties (thermoplastic / thermosetting silicone resin), has no thermoplasticity, and has thermosetting properties. Examples include silicone resins (non-thermoplastic / thermosetting silicone resins).

  The thermoplastic / thermosetting silicone resin is once plasticized (or liquefied) by heating in the B stage and then cured (C stage) by further heating. Specific examples of the one-step reaction curable resin include phenyl silicone resin compositions described in JP-A-2006-037562 and JP-A-2006-119454. As the two-stage reaction curable resin, for example, first to sixth thermoplastic / thermosetting silicone resin compositions (for example, both terminals) described in JP-A-2014-72351 and JP-A-2013-187227 are disclosed. A composition containing an amino-type silicone resin, a composition containing a cage-type octasilsesquioxane) and the like.

  The phenyl silicone resin composition has a phenyl group in the main skeleton which is a siloxane bond. The phenyl silicone resin composition is preferably an addition reaction curable silicone resin composition. Specifically, it contains an alkenyl group-containing polysiloxane, a hydrosilyl group-containing polysiloxane, and a hydrosilylation catalyst, and at least one of the alkenyl group-containing polysiloxane and the hydrosilyl group-containing polysiloxane has a phenyl group. A silicone resin composition etc. are mentioned.

  The phenyl silicone resin composition softens (shows a minimum point) upon further heating as described above, but is harder than a general thermoplastic / thermosetting silicone resin.

  As the non-thermoplastic / thermosetting silicone resin, as the two-stage reaction curable resin, for example, first to eighth condensation / reduction described in JP2010-265436A, JP2013-187227A, and the like. An addition reaction curable silicone resin composition may be mentioned.

  An example of the thermosetting resin that does not take the B stage is an addition reaction curable silicone resin composition. As an addition reaction curable silicone resin composition that does not take the B stage, commercially available products (for example, trade names: KER-2500, KER-6110, manufactured by Shin-Etsu Chemical Co., Ltd., trade names: LR-7665, manufactured by Asahi Kasei Wacker) Can be used.

  Such an addition reaction curable silicone resin composition that does not take the B stage has substantially only a methyl group in the main skeleton that is a siloxane bond, for example. Such a silicone resin composition is a methyl-based silicone resin composition.

  The refractive index of the resin is, for example, 1.30 or more and 1.75 or less. In particular, when the resin is a phenyl-based silicone resin composition, the refractive index thereof is, for example, 1.45 or more, preferably 1.50 or more, more preferably 1.55 or more in the C-stage state. For example, it is 1.75 or less, preferably 1.65 or less. Further, when the resin is a methyl silicone resin composition, the refractive index thereof is, for example, 1.30 or more, further 1.35 or more in the C stage state, and for example, 1.50 or less. is there.

  The content ratio of the resin is, for example, 10% by mass or more, preferably 20% by mass or more, and for example, 90% by mass or less, preferably 70% by mass or less with respect to the light diffusion composition.

  The light diffusing composition can further contain particles such as thixotropic particles and fillers in addition to the above components.

  The thixotropic particle is a thixotropic agent that imparts or improves thixotropy to the light diffusing composition. Thixotropy is a property in which the viscosity gradually decreases when subjected to shear stress, and the viscosity gradually increases when stationary. As a result, the light diffusing particles can be uniformly dispersed in the light diffusing composition (further, the light diffusing layer 4).

  The thixotropic particles preferably include nano silica such as fumed silica (fumed silica) from the viewpoint of light diffusibility.

  The fumed silica may be, for example, either hydrophobic fumed silica whose surface has been hydrophobized by a surface treating agent such as dimethyldichlorosilane or silicone oil, or hydrophilic fumed silica that has not been surface-treated.

The average particle diameter of nano silica (particularly fumed silica) is, for example, 1 nm or more, preferably 5 nm or more, and for example, 200 nm or less, preferably 50 nm or less. The specific surface area of nanosilica (particularly fumed silica) (BET method), for example, ^{50 m} 2 / g or more, preferably not 200 meters ² / g or more, and is, for example, at most 500m ² / g.

  When the light diffusion composition contains thixotropic particles, the content ratio of the thixotropic particles is, for example, 0.1% by mass or more, preferably 0.5% by mass or more with respect to the light diffusion composition, For example, it is 10 mass% or less, Preferably, it is 3 mass% or less.

  The filler is a transparent particle that has a low refractive index difference from the resin. Specifically, particles having an absolute value of the difference in refractive index from the resin of 0.03 or less, and preferably 0.01 or less can be given.

  The refractive index of the filler is, for example, 1.40 or more, preferably 1.45 or more, and for example, 1.60 or less, preferably 1.55 or less.

  Examples of such a filler include inorganic particles and organic particles. Preferably, inorganic particles are used.

  Examples of the inorganic particles include particles of the same material as the light diffusing particles, and preferably include silica particles and composite inorganic oxide particles (such as glass particles).

  Examples of the organic particles include particles of the same material as the light diffusing organic particles.

  The average particle diameter of the filler is, for example, 1.0 μm or more, preferably 5.0 μm or more, and for example, 100 μm or less, preferably 50 μm or less.

  When the filler is contained, the content of the filler is, for example, 10% by mass or more, preferably 20% by mass or more, and, for example, 50% by mass or less, preferably with respect to the light diffusing composition. 30% by mass or less.

  In addition, in the particle | grains used for this invention, even if it is the same material, even if a material is the same, it will distinguish suitably according to the refractive index difference of resin.

In the upper part 41 of the light diffusion layer, the abundance of light diffusion particles per 1 cm ² in plan view is 0.0010 cm ³ or more and 0.0180 cm ³ or less. Preferably, it is 0.0030 cm ³ or more, more preferably 0.0040 cm ³ or more, and preferably 0.0100 cm ³ or less, more preferably 0.0080 cm ³ or less.

In the light diffusion layer side portion 42, the abundance of light diffusion particles per 1 cm ² in side view is 0.0010 cm ³ or more and 0.0180 cm ³ or less. Preferably, it is 0.0030 cm ³ or more, more preferably 0.0040 cm ³ or more, and preferably 0.0100 cm ³ or less, more preferably 0.0080 cm ³ or less.

  By setting both the amount of the light diffusion particles in the light diffusion layer upper portion 41 and the light diffusion layer side portion 42 within the above range, the light emitted in the vertical direction and the orthogonal direction can be evenly and sufficiently diffused. The color uniformity in the angular direction can be improved.

The abundance of light diffusing particles per 1 cm ² in plan view (or side view) is a volume obtained by projecting 1 cm ² of light diffusion layer upper portion 41 (or light diffusion layer side portion 42) in the thickness direction regardless of the thickness. The amount of light diffusing particles present inside.

The abundance of the light diffusing particles can be calculated from the charged amount of the light diffusing composition. Specifically, (1) the volume ratio of each composition contained in the light diffusion composition constituting the light diffusion layer is measured. In addition, about particles, such as light-diffusion particle | grains, a volume can be measured from true specific gravity and mass. (2) Next, the volume X (/ cm ³ ) of the light diffusing particles contained in 1 cm ³ of the light diffusing composition is measured. (3) Next, the vertical length (cm) of the light diffusion layer upper portion 41 or the orthogonal length (cm) of the light diffusion layer side portion 42 is set to the volume X (/ cm ³ ) of the light diffusion particles. Take a ride.

<The manufacturing method of 1st Embodiment>
With reference to FIG. 2A-FIG. 2G, the manufacturing method of the two-layer coating | coated element 1 of 1st Embodiment is demonstrated. The manufacturing method of the two-layer covering element 1 of the first embodiment includes, for example, a temporary fixing sheet preparation step, a temporary fixing step, a phosphor layer forming step, a phosphor layer removing step, a light diffusion layer forming step, and a cutting step. Prepare.

  First, as shown in FIG. 2A, in the temporarily fixing sheet preparation step, a temporarily fixing sheet is prepared.

  The temporarily fixed sheet 50 can be a known or commercially available sheet, and includes, for example, a support base 51 and a pressure-sensitive adhesive layer 52 disposed on the support base 51.

  Examples of the support substrate 51 include polymer films such as polyethylene film and polyester film (PET), for example, ceramic sheets, and flexible sheets such as metal foil.

  The pressure sensitive adhesive layer 52 is disposed on the entire upper surface of the support substrate 51. The pressure sensitive adhesive layer 52 has a sheet shape on the upper surface of the support substrate 51. The pressure-sensitive adhesive layer 52 is formed of a pressure-sensitive adhesive whose pressure-sensitive adhesive force is reduced by, for example, treatment (for example, irradiation of ultraviolet rays or heating). The thickness of the pressure-sensitive adhesive layer 52 is, for example, 1 μm or more, preferably 10 μm or more, and for example, 1000 μm or less, preferably 500 μm or less.

  Next, as shown in FIG. 2B, in the temporary fixing step, the plurality of optical semiconductor elements 2 are temporarily fixed on the temporary fixing sheet 50 at intervals in the left-right direction and the front-rear direction.

  Specifically, the lower surfaces 22 of the plurality of optical semiconductor elements 2 are pressure-bonded to the upper surface of the pressure-sensitive adhesive layer 52. At this time, the optical semiconductor element 2 is pressed against the pressure sensitive adhesive layer 52 so that the plurality of electrodes 24 are buried in the pressure sensitive adhesive layer 52.

  Thereby, the element assembly 7 provided with the temporarily fixing sheet 50 and the some optical semiconductor element 2 is obtained.

  Next, as shown in FIG. 2C, in the phosphor layer forming step, the phosphor layer 3 is disposed on the element assembly 7 so as to cover the optical semiconductor element 2.

  For example, a phosphor layer transfer sheet in which the phosphor layer 3 is disposed on a release sheet is prepared, and then the fluorescent light is applied to the element assembly 7 so that the optical semiconductor element 2 is buried in the phosphor layer 3. The body layer transfer sheet is laminated by hot pressing, and then the release sheet is peeled from the phosphor layer 3.

  For producing the phosphor layer transfer sheet, for example, a phosphor composition (varnish) is prepared, and the phosphor composition is applied to the surface of the release sheet and dried. At this time, when the fluorescent composition contains a thermosetting resin that can be a B-stage, the fluorescent composition is B-staged (semi-cured). Specifically, the fluorescent composition is heated. Thereby, the phosphor layer 3 is formed on the release sheet.

  The hot press temperature is, for example, 40 ° C. or more, preferably 45 ° C. or more, and for example, 200 ° C. or less, preferably 150 ° C. or less.

  The pressure of the hot press is, for example, 0.01 MPa or more, preferably 0.10 MPa or more, and for example, 10 MPa or less, preferably 5 MPa or less.

  The hot press time is, for example, 1 second or more, preferably 3 seconds or more, and for example, 30 minutes or less, preferably 10 minutes or less.

  The hot press can be performed a plurality of times.

  Thereby, the upper surface 21 and the side surface 23 of the optical semiconductor element 2 and the upper surface of the temporary fixing sheet 50 (the upper surface exposed from the optical semiconductor element 2) are covered with the phosphor layer 3. That is, the phosphor layer-covered element assembly 8 including the temporary fixing sheet 50, the plurality of optical semiconductor elements 2, and the phosphor layer 3 is obtained.

  Next, as shown in FIG. 2D, in the phosphor layer removing step, a part of the phosphor layer 3 of the phosphor layer-covered element assembly 8 is removed.

  Specifically, the phosphor layer 3 between the adjacent optical semiconductor elements 2 is removed so that the phosphor layer 3 has a desired size. For example, using a wide dicing saw (dicing blade) 53 (see FIG. 2D), the phosphor layer 3 is cut into a substantially grid shape in plan view.

  Thereby, in the phosphor layer-covered element assembly 8, a gap 54 is formed in a portion where the phosphor layer 3 is removed. For this reason, the phosphor layer 3 is separated into one-to-one correspondence with one optical semiconductor element 2. In the separated phosphor layer 3, a phosphor layer upper part 31 and a phosphor layer side part 32 are formed.

  Next, as shown in FIG. 2E, in the light diffusion layer forming step, the light diffusion layer 4 is disposed on the phosphor layer-covered element aggregate 8 so as to cover the phosphor layer 3.

  For example, a light diffusion layer transfer sheet in which the light diffusion layer 4 is disposed on the release sheet is prepared, and then the phosphor layer-covered element assembly 8 so that the phosphor layer 3 is buried in the light diffusion layer 4. Then, the light diffusion layer transfer sheet is laminated by hot pressing, and then the release sheet is peeled from the light diffusion layer 4.

  For the light diffusion layer transfer sheet, for example, a light diffusion composition (varnish) is prepared, and the light diffusion composition is applied to the surface of the release sheet and dried. At this time, when the light diffusing composition contains a thermosetting resin that can be a B stage, the light diffusing composition is B-staged (semi-cured). Specifically, the light diffusing composition is heated. Thereby, the light-diffusion layer 4 is formed on a peeling sheet.

  The hot pressing conditions for the light diffusion layer transfer sheet are the same as the hot pressing conditions for the phosphor layer transfer sheet.

  Alternatively, the light diffusion composition can be directly potted on the phosphor layer-covered element assembly 8 without using the light diffusion layer transfer sheet, and the light diffusion composition can be compression molded and heated. Layer 4 can be disposed.

  Thereby, the upper surface and side surfaces of the phosphor layer 3 and the upper surface of the gap 54 of the temporary fixing sheet 50 are covered with the light diffusion layer 4. That is, a two-layer covering element assembly 9 including the temporary fixing sheet 50, the plurality of optical semiconductor elements 2, the phosphor layer 3, and the light diffusion layer 4 is obtained.

  Thereafter, when the light diffusion layer 4 and / or the phosphor layer 3 is in the B stage, the two-layer covered element assembly 9 is heated by, for example, an oven. Thereby, the light-diffusion layer 4 and the fluorescent substance layer 3 can be completely hardened (C-staged).

  The heating temperature is, for example, 100 ° C. or more, preferably 120 ° C. or more, and for example, 200 ° C. or less, preferably 160 ° C. or less. The heating time is, for example, 10 minutes or longer, preferably 30 minutes or longer, and for example, 480 minutes or shorter, preferably 300 minutes or shorter. Note that the heating can be performed a plurality of times at different temperatures.

When a phenyl-based silicone resin composition is used as the resin, the content ratio of the phenyl group in the hydrocarbon group directly bonded to the silicon atom in the C-stage product is, for example, 30 mol% or more, preferably 35 mol%. For example, it is 55 mol% or less, preferably 50 mol% or less. The phenyl group content is calculated by ²⁹ Si-NMR. Details of the method for calculating the phenyl group content are described in, for example, WO2011 / 125463.

  Next, as shown in FIG. 2F, in the cutting step, the two-layer covering element assembly 9 is cut (individualized).

  Specifically, the light diffusion layer 4 is completely cut in the thickness direction between the optical semiconductor elements 2 adjacent to each other, as indicated by the phantom lines in FIG. 2E. Thereby, the two-layer covering element assembly 9 is separated into pieces for each of the plurality of optical semiconductor elements 2. Therefore, the light diffusion layer 4 is separated into one-to-one correspondence with one optical semiconductor element 2. In the separated light diffusion layer 4, a light diffusion layer upper portion 41 and a light diffusion layer side portion 42 are formed.

  In order to cut the light diffusion layer 4, for example, a dicing apparatus using a narrow disc-shaped dicing saw, for example, a cutting apparatus using a cutter, for example, a cutting apparatus such as a laser irradiation apparatus is used.

  Next, the temporary fixing sheet 50 is peeled from the optical semiconductor element 2 as indicated by the phantom lines in FIG.

  In this way, the two-layer covering element 1 including the optical semiconductor element 2, the phosphor layer 3, and the light diffusion layer 4 is obtained.

  In this two-layer covering element 1, the amount of light diffusing particles in the light diffusion layer upper portion 41 and the amount of light diffusing particles in the light diffusion layer side portion 42 are substantially the same. The diffusion particles are uniformly dispersed.

  2G, an optical semiconductor device 5 such as a light-emitting diode device can be obtained by flip-chip mounting the two-layer covering element 1 on an electrode substrate 6 such as a diode substrate.

  The electrode substrate 6 has a substantially flat plate shape. Specifically, the electrode substrate 6 is formed of a laminated plate in which a conductor layer is laminated as a circuit pattern on the upper surface of an insulating substrate. The insulating substrate is made of, for example, a silicon substrate, a ceramic substrate, a plastic substrate (for example, a polyimide resin substrate), or the like. The conductor layer is made of a conductor such as gold, copper, silver, or nickel. The conductor layer includes an electrode (not shown) for electrical connection with the single optical semiconductor element 2. The thickness of the electrode substrate 6 is, for example, 25 μm or more, preferably 50 μm or more, and, for example, 2000 μm or less, preferably 1000 μm or less.

<Effect>
In the two-layer covering element 1, the optical semiconductor element 2 in which the upper surface 21 and the side surface 23 emit light, the phosphor layer 3 disposed on the upper surface 21 and the side surface 23 of the optical semiconductor element 2, and the upper surface and side surface of the phosphor layer 3. And a light diffusion layer 4 containing light diffusion particles and a resin. The absolute value of the difference in refractive index between the light diffusing particles and the resin is 0.04 or more and 0.20 or less. Further, the light diffusing particles exist in an amount of 0.0010 cm ³ or more and 0.0180 cm ³ or less per 1 cm ² in plan view of the light diffusion layer upper portion 41, and the light diffusing particles per 1 cm ² in side view of the light diffusion layer side portion 42 0.0010cm ³ or more 0.0180cm ³ exist below.

  Therefore, white light passing through the phosphor layer 3 from the upper surface 21 and the side surface 23 of the optical semiconductor element 2 is evenly distributed by a specific amount of light diffusing particles in the light diffusion layer upper portion 41 and the light diffusion layer side portion 42. And fully diffused. Therefore, the light emitted from the light diffusing layer 4 to the outside in the upward direction and the orthogonal direction is suppressed in color change in the angular direction and is excellent in color uniformity in the angular direction.

<Modification>
In the manufacturing method of the two-layer covering element 1 described above, the amount of light diffusing particles in the light diffusion layer upper portion 41 and the amount of light diffusing particles in the light diffusion layer side portion 42 are substantially the same. However, the light diffusing particles can be dispersed so that the amount of the light diffusing particles in the light diffusing layer upper portion 41 and the amount of the light diffusing particles in the light diffusing layer side portion 42 are different from each other.

  In this embodiment, for example, an upper light diffusing composition for forming the light diffusing layer upper portion 41 and a side light diffusing composition for forming the light diffusing layer side portion 42 are prepared, respectively, As shown by the phantom lines, the side light diffusing composition is disposed so as to cover the side portions of the phosphor layer 3, and finally, the upper light diffusing layer is covered with the upper portion of the phosphor layer 3. Arrange as follows.

  Further, by adjusting the vertical length of the light diffusion layer upper part 41 and the orthogonal length of the light diffusion layer side part 42, the amount of light diffusion particles in the light diffusion layer upper part 41 and the light diffusion layer side part 42 The abundance of the light diffusing particles can be adjusted to each other.

  Also in the two-layer covering element 1 of this embodiment, there are the same functions and effects as the above-described two-layer covering element 1.

  Specific numerical values such as blending ratio (content ratio), physical property values, and parameters used in the following description are described in the above-mentioned “Mode for Carrying Out the Invention”, and the corresponding blending ratio (content ratio) ), Physical property values, parameters, etc. may be replaced with the upper limit values (numerical values defined as “less than” or “less than”) or lower limit values (numbers defined as “greater than” or “exceeded”). it can.

<Preparation of silicone resin composition A>
In accordance with Preparation Example 1 described in Examples of JP-A-2006-037562, A-stage phenyl-based silicone resin composition A (one-stage reaction curable resin capable of becoming B-stage) was prepared.

Next, the A-stage silicone resin composition was reacted (completely cured, C-staged) at 100 ° C. for 1 hour to obtain a product. The ²⁹ Si-NMR of the obtained product was measured, and the proportion (mol%) occupied by the phenyl group in the hydrocarbon group directly bonded to the silicon atom was calculated to be 48%.

  Moreover, the refractive index in the C stage of phenyl-type silicone resin composition A was measured with the Abbe refractometer. As a result, it was 1.56.

<Preparation of silicone resin composition B>
As the silicone resin composition B, a methyl silicone resin composition (silicone resin not taking B stage, “KER2500”, manufactured by Shin-Etsu Silicone Co., Ltd.) was prepared. Moreover, the refractive index in the C stage of the silicone resin composition B was 1.41.

<Materials used in Examples>
Phosphor: Trade name “Y468”, YAG: Ce, average particle diameter 17 μm, manufactured by Nemoto Lumimaterial, Inc. Silica particles: trade name “FB-3SDC”, refractive index 1.45, average particle diameter 3.4 μm, Denka Corporation Manufactured glass particles: refractive index 1.55, composition and composition ratio (% by mass): inorganic particles of SiO ₂ / Al ₂ O ₃ / CaO / MgO = 60/20/15/5, average particle diameter 20 μm
Silicone resin particles: trade name “Tospearl 120”, refractive index 1.42, average particle size 2.0 μm, manufactured by Momentive Performance Materials Japan, Inc. Fumed silica: trade name “R976S”, thixotropic particles, average Example 1 with a particle size of 7 nm, manufactured by Evonik
(Preparation of fluorescent composition)
Silicone resin composition A 41.7g, phosphor 15.0g, glass particles 42.5g and fumed silica 0.85g were mixed to prepare a phosphor composition.

(Preparation of light diffusion composition)
64.2 g of silicone resin composition A, 7.0 g of silica particles, 27.9 g of glass particles, and 0.9 g of fumed silica so that the content ratio of silica particles in the light diffusion composition is 21.8% by volume. A light diffusing composition was prepared by mixing.

(Manufacture of double-layer covered elements)
A two-layer coated element was manufactured according to FIGS. 2A-2F.

  Specifically, first, a plurality of optical semiconductor elements (1.1 mm square, thickness 150 μm, manufactured by Epistar) having electrodes provided on the lower surface were prepared. Next, a plurality of alignment plates were arranged on a temporary fixing sheet including a support plate (stainless steel carrier) and an adhesive sheet ("Riva Alpha", manufactured by Nitto Denko Corporation) arranged on the upper surface of the support plate (see FIG. 2B). .

  Next, the phosphor layer was disposed on the temporary fixing sheet so as to cover the optical semiconductor element (see FIG. 2C). Specifically, the phosphor composition (varnish) was applied to the surface of the release sheet, dried and heated to prepare a B-stage phosphor layer transfer sheet. Subsequently, this phosphor layer transfer sheet was hot-pressed at 90 ° C. for 10 minutes at a pressure of 0.1 MPa against the element assembly in which the optical semiconductor elements were temporarily fixed to the temporary fixing sheet. Thereby, a phosphor layer-covered element assembly was obtained.

  Next, a part of the phosphor layer of the phosphor layer-covered element assembly was removed into a grid pattern in a plan view using a wide dicing saw (see FIG. 2D).

  Next, the light diffusion layer was disposed on the phosphor layer-covered element assembly so as to cover the phosphor layer (see FIG. 2E). Specifically, the light diffusion composition A (varnish) was applied to the surface of the release sheet, dried and heated to prepare a B-stage light diffusion layer transfer sheet. Subsequently, this light diffusion layer transfer sheet was hot pressed at 90 ° C. for 10 minutes at a pressure of 0.1 MPa against the phosphor layer-covered element assembly. Thereby, a two-layer covered element assembly was obtained.

  Thereafter, the two-layer coated element assembly was left in an oven at 150 ° C. for 3 hours. Thereby, the light diffusion layer and the phosphor layer were completely cured.

  Next, the light diffusion layer between adjacent optical semiconductor elements was cut to separate the optical semiconductor elements. Subsequently, the temporarily fixing sheet 50 was peeled from the optical semiconductor element 2.

  Thereby, a two-layer covering element was produced. Note that. The thickness L1 of the upper part of the phosphor layer was 150 μm, and the length L2 of the phosphor layer side parts (front part, rear part, left part, right part) was 70 μm. The thickness L3 of the upper part of the light diffusion layer was 200 μm, and the length L4 of the side part of the light diffusion layer (front part, rear part, left part, right part) was 200 μm.

Example 2
A two-layer coated element was produced in the same manner as in Example 1 except that the light diffusion composition was prepared so that the content ratio of the silica particles in the light diffusion composition was 14.0% by volume.

Example 3
65.6 g of silicone resin composition A, 5.0 g of silicone resin particles, 28.5 g of glass particles, and fumed silica so that the content ratio of the silicone resin particles in the light diffusion composition is 5.4% by volume. 1.0 g was mixed to prepare a light diffusing composition. A two-layer coated element was produced in the same manner as in Example 1 except that this light diffusing composition was used.

Examples 4-5
A two-layer covering element was produced in the same manner as in Example 1 except that the thickness L3 of the upper part of the light diffusion layer and the length L4 of the side part of the light diffusion layer were changed to the thicknesses and lengths shown in Table 1.

Example 6
A two-layer coated element was produced in the same manner as in Example 1 except that the phosphor layer was subjected to the following steps.

  The upper light diffusion composition was prepared so that the content ratio of the silica particles in the light diffusion composition was 4.7% by volume. Moreover, the light-diffusion composition for side parts from which the content rate of the silica particle in a light-diffusion composition becomes 21.8 volume% was prepared. In the phosphor layer forming step shown in FIG. 2E, as shown by the phantom line, first, the side light diffusing composition is disposed so as to cover the side part of the phosphor layer 3, and then the light diffusion for the upper part. The layer composition was placed to cover the phosphor layer top and side light scatter composition. Note that the thickness L3 of the upper part of the light diffusion layer and the length L4 of the side part of the light diffusion layer were the thicknesses and lengths shown in Table 1.

Example 7
In the light diffusing composition, a two-layer coated element was produced in the same manner as in Example 6 except that silicone resin particles were used instead of silica particles.

Example 8
Silicone resin composition B (50.8 g), glass particles (40.9 g) and fumed silica (1.0 g) were mixed so that the content ratio of the glass particles in the light diffusion composition was 21.8% by volume. A light diffusing composition was prepared.

  Further, in the same manner as in the side light diffusing composition, an upper light diffusing composition was prepared so that the content ratio of the glass particles in the light diffusing composition was 4.7% by volume.

  The phosphor layer was formed in the same manner as in Example 6. For the formation of the light diffusing layer, since the silicone resin composition B cannot take the B stage, the light diffusing composition (liquid) is potted on the phosphor layer-covered element assembly, and a compression molding machine is used. Molded. Thereby, a two-layer covering element was produced.

Examples 9-12
A two-layer covering element was produced in the same manner as in Example 1 except that the thickness L1 of the upper part of the phosphor layer and the length L2 of the side part of the phosphor layer were changed to the thicknesses and lengths shown in Table 1.

Comparative Example 1
A two-layer coated element was produced in the same manner as in Example 1 except that the light diffusing composition was prepared so that the content ratio of the silica particles in the light diffusing composition was 3.4% by volume.

Comparative Example 2
In the light diffusing composition, a two-layer covering element was produced in the same manner as in Example 1 except that the light diffusing composition was prepared without blending silica particles and glass particles.

Comparative Example 3
A two-layer coated element was produced in the same manner as in Example 6 except that the upper light diffusing composition was prepared so that the content ratio of the silica particles in the light diffusing composition was 30.2% by volume.

Comparative Example 4
A two-layer covering element was produced in the same manner as in Example 1 except that the thickness L3 of the upper part of the light diffusion layer and the length L4 of the side part of the light diffusion layer were changed to the thicknesses and lengths shown in Table 1.

Comparative Example 5
In the upper light diffusing composition, titanium oxide (content ratio 4.7 volume%) was used instead of silica particles (content ratio 4.7 volume%). In the side light diffusing composition, titanium oxide (content ratio 21.8% by volume) was used instead of silica particles (content ratio 21.8% by volume). Except for these, a double-layer covered element was produced in the same manner as in Example 6.

Comparative Example 6
In the upper light diffusing composition, the upper light diffusing composition was prepared so that the content ratio of the glass particles was 4.7% by volume without blending the silica particles. In the side light diffusing composition, the side light diffusing composition was prepared such that the silica particles were not blended and the glass particle content was 21.8% by volume. Except for these, a double-layer covered element was produced in the same manner as in Example 6.

(Measurement of thickness)
The thicknesses of the phosphor layer and the diffusion layer were measured with a measuring meter (linear gauge, manufactured by Citizen).

(Color uniformity in angular direction)
In the two-layer coated element of each example and each comparative example, the chromaticity (CIE, y) of light emitted from the front direction (0 °: upward direction) to the oblique direction (−60 ° to 60 °) is 5 °. Measured in steps, the difference (Δu′v ′) between the maximum and minimum chromaticity in the range of −60 ° to 60 ° was calculated. As the chromaticity, an instantaneous multi-metering system (“MCPD-9800”, manufactured by Otsuka Electronics Co., Ltd.) was used, and a current of 300 mA was applied to the two-layer covering element. The results are shown in Tables 1 and 2.

DESCRIPTION OF SYMBOLS 1 Phosphor layer light diffusion layer covering optical semiconductor element 2 Optical semiconductor element 3 Phosphor layer 4 Light diffusion layer 21 Upper surface 23 Side surface 31 Phosphor layer upper part 32 Phosphor layer side part 41 Light diffusion layer upper part 42 Light diffusion layer side part

Claims (3)

An optical semiconductor element whose top and side surfaces emit light;
A phosphor layer disposed on an upper surface and a side surface of the optical semiconductor element;
A light diffusing layer that is disposed on the top and side surfaces of the phosphor layer and contains light diffusing particles and a resin;
The absolute value of the difference in refractive index between the light diffusing particles and the resin is 0.04 or more and 0.20 or less,
The light diffusing particles are present in an amount of 0.0010 cm ³ or more and 0.0180 cm ³ or less per 1 cm ² in plan view of the light diffusion layer disposed on the upper surface of the optical semiconductor element,
The phosphor layer light diffusion, wherein the light diffusion particles are present in an amount of 0.0010 cm ³ or more and 0.0180 cm ³ or less per 1 cm ² of the light diffusion layer disposed on the side surface of the optical semiconductor element in a side view. Layer-coated optical semiconductor element.   The ratio (L1 / L2) of the vertical length L1 in the upper part of the phosphor layer and the orthogonal length L2 in the side part of the phosphor layer is 1.0 or more and 3.0 or less. The phosphor layer light diffusion layer-coated optical semiconductor element according to claim 1.   The ratio (L3 / L4) of the vertical length L3 at the top of the light diffusion layer and the orthogonal length L4 at the side of the light diffusion layer is 0.8 or more and 1.2 or less. The phosphor layer light diffusion layer-coated optical semiconductor element according to claim 1 or 2.

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