Wavelength conversion member, light emitting device, and method for manufacturing wavelength conversion member

Abstract

To provide a wavelength conversion member, a light-emitting device and a method for manufacturing a wavelength conversion member which can maintain high light-emitting intensity of a phosphor having a perovskite-type structure.SOLUTION: A wavelength conversion member includes a wavelength conversion layer which includes a translucent member containing a resin, and a phosphor having a perovskite-type structure and a composition of ABX3, and a first intermediate layer provided between the translucent member and the wavelength conversion layer. A method for manufacturing a wavelength conversion member includes a step of forming a first intermediate layer on the surface of a first translucent member containing a resin, and a step of forming a first wavelength conversion layer containing a first phosphor having a perovskite-type structure on the surface of the first intermediate layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a wavelength conversion member, a light emitting device, and a method for manufacturing a wavelength conversion member. [Background technology]

[0002] Light-emitting devices that use light-emitting elements such as light-emitting diodes (LEDs) or laser diodes (LDs) are light sources with high conversion efficiency and are used in a wide range of fields, such as light-emitting devices for automotive and interior lighting, backlight light sources for image display devices that use liquid crystal, illumination, and light source devices for projectors.

[0003] Compounds having a perovskite structure are of increasing interest as fluorescent materials with a narrow half-width of the emission spectrum and excellent color purity as phosphors for use in light-emitting devices. For example, Patent Document 1 discloses a composition for forming a phosphor film for use in a light-emitting device, the composition comprising a compound having a perovskite structure, inorganic particles, a solvent, a polymerizable compound, at least one compound selected from the group consisting of ammonia, amines, and carboxylic acids, and silazane or a modified product thereof. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 022194 Summary of the Invention [Problem to be solved by the invention]

[0005] When using a phosphor having a perovskite structure, further improvement is required to maintain the emission intensity.

[0006] An object of one aspect of the present invention is to provide a wavelength conversion member, a light emitting device, and a method for manufacturing a wavelength conversion member that are capable of maintaining the high luminous intensity of a phosphor having a perovskite structure. [Means for solving the problem]

[0007] A first aspect of the present invention is a wavelength conversion layer including a transparent member containing a resin, a first phosphor having a perovskite structure and a composition of ABX3, and a first intermediate layer provided between the transparent member and the wavelength conversion layer, wherein A is Rb + , CH3NH3 + , and Cs + and B is at least one cation selected from the group consisting of Pb 2+ , and Sn 2+ and X is at least one metal ion selected from the group consisting of F - , Cl - , Br - , and I - The wavelength converting member is at least one anion selected from the group consisting of:

[0008] A second aspect is a light emitting device including the wavelength conversion member and an excitation light source.

[0009] A third aspect includes the steps of: forming a first intermediate layer on a surface of a first light-transmissive member containing a resin; forming a first wavelength conversion layer on the surface of the first intermediate layer, the first wavelength conversion layer including a first phosphor having a perovskite structure and having a composition of ABX3; forming a second intermediate layer on the surface of the first wavelength conversion layer; and forming a second wavelength conversion layer on the surface of the second intermediate layer, the second wavelength conversion layer including a second phosphor having an emission peak wavelength in a wavelength range different from that of the first phosphor, + , CH3NH3 + , and Cs + and B is at least one cation selected from the group consisting of Pb 2+ , and Sn 2+ and X is at least one metal ion selected from the group consisting of F - , Cl - , Br - , and I - The present invention relates to a method for producing a wavelength conversion member, in which the anion is at least one type selected from the group consisting of: Effect of the Invention

[0010] According to one aspect of the present invention, it is possible to provide a wavelength conversion member, a light emitting device, and a method for manufacturing a wavelength conversion member that can maintain the high luminous intensity of a phosphor having a perovskite structure and having a composition of ABX3. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view showing the structure of a wavelength conversion member according to a first embodiment. [Diagram 2] 3 is a schematic cross-sectional view showing a structure of a light-transmitting member containing resin. FIG. [Diagram 3] FIG. 11 is a schematic cross-sectional view of a wavelength conversion member according to a second embodiment. [Figure 4] FIG. 11 is a schematic cross-sectional view of a wavelength conversion member according to a third embodiment. [Diagram 5] FIG. 11 is a schematic cross-sectional view of a wavelength conversion member according to a fourth embodiment. [Figure 6] FIG. 13 is a schematic cross-sectional view of a wavelength conversion member according to a fifth embodiment. [Figure 7] FIG. 13 is a schematic cross-sectional view of a wavelength conversion member according to a sixth embodiment. [Figure 8] FIG. 13 is a schematic cross-sectional view of a wavelength conversion member according to a seventh embodiment. [Figure 9] FIG. 13 is a schematic cross-sectional view of a wavelength conversion member according to an eighth embodiment. [Figure 10] FIG. 13 is a schematic cross-sectional view of a wavelength conversion member according to a ninth embodiment. [Figure 11] FIG. 23 is a schematic cross-sectional view of a wavelength conversion member according to a tenth embodiment. [Figure 12] FIG. 21 is a schematic cross-sectional view of a wavelength conversion member according to an eleventh embodiment. [Figure 13] 4 is a flowchart showing a method for manufacturing a wavelength conversion member according to the first embodiment. [Figure 14] 10 is a flowchart showing a method for manufacturing a wavelength conversion member according to a second embodiment. [Figure 15]13 is a flowchart showing a method for manufacturing a wavelength conversion member according to the third embodiment. [Figure 16] 10 is a flowchart showing a method for manufacturing a wavelength conversion member according to a fourth embodiment. [Figure 17] 13 is a flowchart showing a method for manufacturing a wavelength conversion member according to the fifth embodiment. [Figure 18] 13 is a flowchart showing a method for manufacturing a wavelength conversion member according to a sixth embodiment. [Figure 19] 13 is a flowchart showing a method for manufacturing a wavelength conversion member according to a seventh embodiment. [Figure 20] 1 is a schematic cross-sectional view of a light emitting device according to a first embodiment. [Figure 21] 1 is a schematic perspective view of a light emitting device according to a first embodiment. [Figure 22] FIG. 6 is a schematic cross-sectional view of a light emitting device according to a second embodiment. [Diagram 23] FIG. 11 is a schematic plan view of a light emitting device according to a second embodiment. [Figure 24] FIG. 1 is a schematic plan view of an image display device showing an edge-light type backlight structure according to a first embodiment. [Diagram 25] FIG. 11 is a schematic cross-sectional view of an image display device showing a direct type backlight structure according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The wavelength conversion member and the light emitting device according to the present invention will be described below based on one embodiment. However, the embodiment shown below is an example for realizing the technical idea of ​​the present invention, and the present invention is not limited to the wavelength conversion member, the light emitting device, and the manufacturing method of the wavelength conversion member described below. The relationship between the color name and the chromaticity coordinate, and the relationship between the wavelength range of light and the color name of monochromatic light are in accordance with JIS Z8110. In this specification, the terms "sheet", "film", "layer", and the like are not distinguished from each other based only on the difference in the name. Therefore, for example, "film" is used to mean a member that can be called a sheet, and "sheet" is used to mean a member that can be called a film.

[0013] A wavelength conversion member according to the first embodiment will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a wavelength conversion member according to the first embodiment. A wavelength conversion member 50 includes a translucent member 40 containing a resin, a wavelength conversion layer 20 containing a phosphor having a perovskite structure, and a first intermediate layer 30 provided between the translucent material 40 and the wavelength conversion layer 20. However, for convenience of explanation, the sizes, thicknesses, etc. of each layer in each drawing are merely examples and are exaggerated.

[0014] As a phosphor having a perovskite structure, there is a phosphor having an ABX3 type perovskite structure. In the perovskite structure, A is a component located at each vertex of a hexahedron with B at the center, and Rb + , CH3NH3 + , and Cs + In the perovskite structure, B is a component located at the center of a hexahedron with A at the vertex and an octahedron with X at the vertex, and Pb 2+ , and Sn 2+ In the perovskite structure, X represents a component located at each vertex of an octahedron with B at the center, and F - , Cl - , Br - , and I - The anion is at least one selected from the group consisting of:

[0015] The phosphor having a perovskite structure is preferably a cesium lead halide. The halogen contained in the cesium lead halide is preferably at least one selected from the group consisting of fluorine, chlorine, bromine and iodine. When the halogen contained in the cesium lead halide is at least one selected from the group consisting of fluorine, chlorine, bromine and iodine, it is easy to obtain a phosphor that has a perovskite structure and emits light.

[0016] The phosphor having a perovskite structure includes a cesium lead halide having a composition represented by CsPbBr3, and may include a cesium lead halide having a composition represented by Cs4PbBr6. The cesium lead halide having a composition represented by CsPbBr3 with a perovskite structure has high light absorption ability, high emission intensity, and vivid emission color. In addition, the phosphor having a perovskite structure has a narrow half-width of the emission peak in the emission spectrum and good color purity, so that when mixed color light is emitted together with light of other wavelength regions, color reproducibility is improved.

[0017] The phosphor may contain two or more halogens in the cesium lead halide having a perovskite structure. The cesium lead halide having a perovskite structure may have a composition represented by the following formula (I). CsPb(Br 1-x Ha 1 x )3(I) (In the above formula (I), Ha 1 is at least one selected from the group consisting of F, Cl, and I, and x satisfies 0≦x<1.0. x may satisfy 0.01≦x≦0.99, may satisfy 0.02≦x≦0.98, or may satisfy 0.03≦x≦0.95.

[0018] Cs4PbBr6 contained in the phosphor is a transparent crystal that ideally does not emit light when irradiated with visible light. It is speculated that if there are trace amounts of impurities in the crystal having the composition represented by Cs4PbBr6 contained in the phosphor, it may emit light when irradiated with visible light. If there are no impurities in the crystal having the composition represented by Cs4PbBr6 and it is a crystal having a pure composition represented by Cs4PbBr6, that is, if it is a crystal having an ideal composition represented by Cs4PbBr6, it is speculated that it will not emit light when irradiated with visible light. For example, a complex of CsPbBr3 and Cs4PbBr6 is formed by evaporating CsBr and PbBr2 as raw materials. By forming a complex containing CsPbBr3 dispersed in a transparent matrix of Cs4PbBr6, CsPbBr3 is stabilized, and the electrons and holes involved in the emission do not move to large aggregated particles as in the case where CsPbBr3 is present in an aggregated state, and therefore high emission intensity can be maintained.

[0019] When the phosphor is a cesium lead halide, the phosphor preferably contains cesium lead halide having a composition represented by CsPbBr3 in a range of 1% by mass to 50% by mass with respect to the total amount of the phosphor. By containing cesium lead halide having a composition represented by CsPbBr3 in a range of 1% by mass to 50% by mass, a wavelength conversion member with high luminous intensity can be provided. The phosphor may contain cesium lead halide having a composition represented by CsPbBr3 in a range of 2% by mass to 45% by mass, 3% by mass to 40% by mass, or 5% by mass to 35% by mass.

[0020] When the phosphor contains a cesium lead halide having a composition represented by CsPbBr3, and the content of the cesium lead halide having a composition represented by CsPbBr3 is within the range of 1 mass% to 50 mass% relative to the total amount of the phosphor, it is preferable that the phosphor emits light having an emission peak wavelength within the range of 500 nm to 610 nm, which is longer than the wavelength of the excitation light, when excited by light having an emission peak wavelength within the range of 380 nm to 500 nm. The emission peak wavelength of the light emitted by the phosphor when excited by light having an emission peak wavelength within the range of 380 nm to 500 nm is more preferably within the range of more than 500 nm to 600 nm, even more preferably within the range of 510 nm to 570 nm, and even more preferably within the range of 520 nm to 560 nm.

[0021] When the phosphor contains a cesium lead halide having a composition represented by CsPbBr3, and the content of the cesium lead halide having a composition represented by CsPbBr3 is within a range of 1 mass% to 50 mass% relative to the total amount of the phosphor, the half-width in the emission spectrum of the phosphor is preferably narrow, and the half-width is preferably 35 nm or less, more preferably 30 nm or less, and even more preferably 25 nm or less. The half-width refers to the full width at half maximum (FWHM) of the emission peak in the emission spectrum, and refers to the wavelength width of the emission peak that shows 50% of the maximum value of the emission peak in the emission spectrum. A phosphor having an emission peak with a narrow half-width has high color purity and good color reproducibility.

[0022] The wavelength conversion layer includes a phosphor having the above-mentioned perovskite structure and having a composition of ABX3. The wavelength conversion layer including the above-mentioned phosphor having the perovskite structure and having a composition of ABX3 may be referred to as a first wavelength conversion layer. The wavelength conversion layer preferably includes 99% by mass or more of cesium lead halide, and may include 99.5% by mass or more, 99.8% by mass or more, or may include 100% by mass of cesium lead halide. When the wavelength conversion layer includes 99% by mass or more of cesium lead halide, high luminous intensity can be maintained.

[0023] The thickness of the wavelength conversion layer is preferably in the range of 10 nm to 10 μm. If the thickness of the wavelength conversion layer is in the range of 10 nm to 10 μm, the wavelength conversion member having high emission intensity and satisfying the demand for miniaturization can be provided by the phosphor having a perovskite structure and a composition of ABX3 contained in the wavelength conversion layer. The thickness of the wavelength conversion layer may be in the range of 20 nm to 5 μm, 30 nm to 3 μm, or 50 nm to 1 μm.

[0024] The first intermediate layer is disposed between the resin-containing light-transmitting member and the wavelength conversion layer. The first intermediate layer preferably contains at least one oxide selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, magnesium oxide, titanium oxide, cerium oxide, zinc oxide, and tin oxide, and may contain two or more oxides. The first intermediate layer preferably contains a transparent inorganic oxide, and more preferably is made of a transparent inorganic oxide. The first intermediate layer is preferably disposed on the entire surface of the resin-containing light-transmitting member on the wavelength conversion layer side. The phosphor having a perovskite structure and a composition of ABX3 contained in the wavelength conversion layer reacts with the resin contained in the light-transmitting member due to heat or the like generated when the excitation light source emits light, causing a change in crystal structure and making it easy for the emission intensity to decrease. The presence of the first intermediate layer between the light-transmitting member and the wavelength conversion layer suppresses the reaction between the phosphor having a perovskite structure and a composition of ABX3 contained in the wavelength conversion layer and the resin contained in the light-transmitting member, thereby suppressing a decrease in the emission intensity of the phosphor. In a wavelength conversion member according to an embodiment described below, the first intermediate layer can be the same as the first intermediate layer of the wavelength conversion member according to the first embodiment.

[0025] The thickness of the first intermediate layer is preferably in the range of 0.001 to 1000, where the thickness of the wavelength conversion layer is 1. If the thickness of the first intermediate layer is in the range of 0.001 to 1000, where the thickness of the wavelength conversion layer is 1, a reaction between the phosphor having a perovskite structure and a composition of ABX3 contained in the wavelength conversion layer and the resin contained in the light-transmitting member can be suppressed, and a decrease in the luminous intensity of the phosphor can be suppressed. The thickness of the first intermediate layer may be in the range of 0.005 to 500, or may be in the range of 0.01 to 100, where the thickness of the wavelength conversion layer is 1.

[0026] Specifically, the thickness of the first intermediate layer may be in the range of 0.1 nm or more and 10 μm or less, in the range of 0.5 nm or more and 1 μm or less, in the range of 1 nm or more and 500 nm or less, in the range of 3 nm or more and 300 nm or less, or in the range of 5 nm or more and 100 nm or less.

[0027] The light-transmitting member includes a resin and also functions as a protective member for the wavelength conversion layer. The light-transmitting member may be a single-layer member including a resin, or may be a member in which layers of different types of resins are laminated. The light-transmitting member may include layers of different types of resins and include a barrier layer formed of an inorganic oxide. The light-transmitting member may be a commercially available optical film or protective film in which layers of different types of resins are laminated and which includes a barrier layer formed of an inorganic oxide. When the light-transmitting member is composed of layers including a plurality of resins, it may include a functional layer having a function such as an adhesive layer or an antistatic layer for easily bonding the light-transmitting member to other members. The total thickness of the light-transmitting member is not particularly limited, but is preferably in the range of 5 μm to 500 μm, and more preferably 10 μm to 450 μm, in order to meet the demands for strength and miniaturization. below The thickness may be within the range, 15 μm or more and 400 μm or less, or 20 μm or more and 350 μm or less.

[0028] 2 is a schematic cross-sectional view showing an example of a light-transmitting member in which a plurality of layers of different types of resins are laminated. The light-transmitting member 40 may have a laminated structure in which, for example, a first bonding layer 43, a first protective layer 44, a second bonding layer 45, a second protective layer 46, a gas barrier layer or water vapor barrier layer 47, and an antistatic layer or third bonding layer 48 are laminated.

[0029] When the light-transmitting member is a member in which a plurality of layers are laminated as in FIG. 2, examples of the resin constituting the first protective layer and the second protective layer include polyester-based resins.

[0030] For example, the polyester-based resin constituting the first protective layer and the second protective layer may be a homopolyester or a copolymer polyester. The homopolyester is preferably one obtained by polycondensing an aromatic dicarboxylic acid such as terephthalic acid or 2,6-naphthalenedicarboxylic acid with an aliphatic glycol. A representative polyester resin may be, for example, polyethylene terephthalate (PET). The dicarboxylic acid component contained in the copolymer polyester may be one or more of isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, etc., and the glycol component may be one or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexanedimethanol, neopentyl glycol, etc. A representative example of the copolymer polyester may be polyethylene-2,6-naphthalenedicarboxylate (PEN).

[0031] The thickness of the first protective layer and the second protective layer is, for example, in the range of 5 μm to 400 μm, or may be in the range of 10 μm to 350 μm, or may be in the range of 20 μm to 300 μm, or may be in the range of 30 μm to 250 μm. The thickness of the first protective layer and the second protective layer may be the same or different.

[0032] The acrylic resin constituting the first bonding layer preferably contains a compound having a carbon-carbon double bond with a monofunctional (meth)acrylate group, a bifunctional (meth)acrylate group, a polyfunctional (meth)acrylate group, a vinyl group, an allyl group, etc. The term "(meth)acrylate" refers to acrylate and / or methacrylate.

[0033] The second bonding layer may be made of, for example, a polyisophthalic acid resin, which is a resin made of a polycarboxylic acid and a polyhydroxy compound. Examples of the polycarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, and phthalic acid. Examples of the polyhydroxy compound include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,6-hexanediol. One or more of these polycarboxylic acids and polyhydroxy compounds may be appropriately selected, and a polyester resin may be synthesized by a conventional polycondensation reaction.

[0034] The gas barrier layer or water vapor barrier layer preferably contains at least one oxide selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, magnesium oxide, titanium oxide, cerium oxide, zinc oxide, and tin oxide, and may contain two or more oxides. The gas barrier layer or water vapor barrier layer contained in the light-transmitting member may contain the same oxide as the intermediate layer described above, or may contain a different oxide. The gas barrier layer or water vapor barrier layer contained in the light-transmitting member may be formed by a deposition method such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). The thickness of the gas barrier layer or water vapor barrier layer contained in the light-transmitting member is not particularly limited, and may be in the range of 0.1 nm to 500 nm, 1 nm to 300 nm, or 5 nm to 100 nm.

[0035] The antistatic layer may be composed of a layer containing, for example, polyimide. The third bonding layer may be composed of a layer containing, for example, a urethane-based resin. Examples of polyester polyols constituting the urethane-based resin include polyvalent carboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or their acid anhydrides and polyhydric alcohols (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, etc.). Examples of polyisocyanates constituting the urethane resin include tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, etc.

[0036] The thickness of the first bonding layer, the second bonding layer, and the third bonding layer is in the range of 0.005 μm to 10 μm, or may be in the range of 0.01 μm to 5 μm, or may be in the range of 0.05 μm to 2 μm. The first bonding layer, the second bonding layer, and the third bonding layer may have the same thickness or different thicknesses.

[0037] Hereinafter, each embodiment will be described with reference to the drawings as necessary. Fig. 3 is a schematic cross-sectional view showing a schematic configuration of a wavelength conversion member according to a second embodiment. The wavelength conversion member 50 includes a first light-transmissive member 41 and a second light-transmissive member 42, a wavelength conversion layer 20 disposed between the first light-transmissive member 41 and the second light-transmissive member 42, a first intermediate layer 31 disposed on the first light-transmissive member 41 side of the wavelength conversion layer 20, a second intermediate layer 32 disposed on the second light-transmissive member 42 side of the wavelength conversion layer 20, and a first adhesive layer 55 bonding the second intermediate layer 32 and the second light-transmissive member 42.

[0038] The first and second light-transmitting members may be the same as the light-transmitting members according to the first embodiment. In order to satisfy the demands for strength and compactness, the thickness of the first and second light-transmitting members is preferably in the range of 5 μm to 500 μm, and more preferably 10 μm to 450 μm. m or less The wavelength conversion member according to the embodiment described later may be in the range of 15 μm or more and 400 μm or less, or may be in the range of 20 μm or more and 350 μm or less. In the wavelength conversion member according to the embodiment described later, the first light transmissive member and the second light transmissive member may be the same as the first light transmissive member and the second light transmissive member of the wavelength conversion member according to the second embodiment.

[0039] The second intermediate layer may be the same as the first intermediate layer according to the first embodiment. The thickness of the first intermediate layer and the second intermediate layer is preferably in the range of 10 nm to 10 μm, may be in the range of 20 nm to 5 μm, may be in the range of 30 nm to 3 μm, or may be in the range of 50 nm to 1 μm, in order to suppress the decrease in the emission intensity of the phosphor and to satisfy the demand for miniaturization. The thickness of the first intermediate layer and the second intermediate layer when the thickness of the wavelength conversion layer is 1 is preferably in the range of 0.01 to 1000, may be in the range of 0.05 to 500, or may be in the range of 0.1 to 100, as in the above intermediate layer.

[0040] The first adhesive layer preferably contains at least one resin selected from the group consisting of polyester resin, acrylic resin, acrylic urethane resin, polyester acrylate resin, polyurethane acrylate resin, epoxy acrylate resin, and urethane resin, and may contain two or more resins. The thickness of the first adhesive layer can be in the range of 0.005 μm to 10 μm.

[0041] FIG. 4 is a schematic cross-sectional view showing a schematic configuration of a wavelength conversion member according to the third embodiment. The wavelength conversion member 50 according to the third embodiment includes a first intermediate layer 31, a wavelength conversion layer 20, a second intermediate layer 32, and a first adhesive layer 55, which are disposed between the first light-transmissive member 41 and the second light-transmissive member 42, as in the wavelength conversion member 50 according to the second embodiment. The wavelength conversion member 50 according to the third embodiment may include a sealing layer 59 that covers the side surfaces of the first intermediate layer 31, the wavelength conversion layer 20, and the second intermediate layer 32. The sealing layer 59 is preferably disposed around the first intermediate layer 31, the wavelength conversion layer 20, and the second intermediate layer 32 so as not to come into contact with the side surfaces of the wavelength conversion layer 20 in order to suppress adverse effects on the wavelength conversion layer 20. By disposing the sealing layer 59 around the first intermediate layer 31, the wavelength conversion layer 20, and the second intermediate layer 32, the periphery of the wavelength conversion layer 20 is protected, and the wavelength conversion layer 20 is less likely to come into contact with moisture, gases contained in the air, and the like, and deterioration of the wavelength conversion layer can be suppressed.

[0042] The sealing layer can be made of the same material as the first adhesive layer according to the first embodiment.

[0043] 5 is a schematic cross-sectional view showing a schematic configuration of a wavelength conversion member according to the fourth embodiment. The wavelength conversion member 50 preferably includes a first light-transmissive member 41 and a second light-transmissive member 42, a wavelength conversion layer 20 disposed between the first light-transmissive member 41 and the second light-transmissive member 42, a first intermediate layer 31 disposed on the first light-transmissive member 41 side of the wavelength conversion layer 20, and a second adhesive layer 56 disposed around the wavelength conversion layer 20 and having a thickness larger than that of the wavelength conversion layer 20 so that the wavelength conversion layer 20 does not come into contact with the second light-transmissive member 42. By arranging a second adhesive layer having a thickness greater than that of the wavelength conversion layer around the wavelength conversion layer so that the wavelength conversion layer does not come into contact with the second translucent member, the wavelength conversion layer and the second translucent member do not come into contact with each other, and the reaction between the phosphor contained in the wavelength conversion layer and the resin contained in the second translucent member is suppressed, thereby suppressing a decrease in the luminous intensity of the phosphor. The wavelength conversion layer may be the same as the wavelength conversion layer of the wavelength conversion member according to the first embodiment.

[0044] The second adhesive layer may be made of the same material as the first adhesive layer according to the first embodiment. Specifically, the thickness of the second adhesive layer may be in the range of 100 nm to 18 μm, or in the range of 200 nm to 17 μm.

[0045] The wavelength conversion member may include a second wavelength conversion layer including a second phosphor having a perovskite structure and having an emission peak wavelength in a wavelength range different from that of the phosphor having the ABX3 composition. When the wavelength conversion member includes the second wavelength conversion layer, the phosphor having the perovskite structure and having the ABX3 composition can be used as the first phosphor, and the wavelength conversion layer including this first phosphor can be used as the first wavelength conversion layer.

[0046] 6 is a schematic cross-sectional view showing a schematic configuration of a wavelength conversion member according to the fifth embodiment. The wavelength conversion member 50 includes a first light-transmissive member 41 and a second light-transmissive member 42, a first wavelength conversion layer 21 disposed between the first light-transmissive member 41 and the second light-transmissive member 42, a first intermediate layer 31 disposed on the first light-transmissive member 41 side of the first wavelength conversion layer 21, and a second intermediate layer 32 disposed on the second light-transmissive member 42 side of the first wavelength conversion layer 21, and a second wavelength conversion layer 22 between the second intermediate layer 32 and the second light-transmissive member 42. In the wavelength conversion member 50, a third adhesive layer 57 is disposed between the second intermediate layer 32 and the second wavelength conversion layer 22, and the second intermediate layer 32 and the second wavelength conversion layer 22 are bonded to each other, but the second intermediate layer 32 and the second wavelength conversion layer 22 may be directly bonded to each other without the third adhesive layer 57.

[0047] FIG. 7 is a schematic cross-sectional view showing a schematic configuration of a wavelength conversion member according to the sixth embodiment. As in the fifth embodiment described above, the wavelength conversion member 50 includes, between the first light-transmissive member 41 and the second light-transmissive member 42, a first intermediate layer 31, a first wavelength conversion layer 21, a second intermediate layer 32, a third adhesive layer 57, and a second wavelength conversion layer 22, in that order from the first light-transmissive member 41 side. The wavelength conversion member according to the sixth embodiment includes, between the first light-transmissive member 41 and the second light-transmissive member 42, a sealing layer 59 that covers the side surfaces of the first intermediate layer 31, the first wavelength conversion layer 21, the second intermediate layer 32, the third adhesive layer 57, and the second wavelength conversion layer 22. The sealing layer 59 can be made of the same material as the sealing layer described above. By providing such a sealing layer 59, the side surfaces of the first wavelength conversion layer 21 and the second wavelength conversion layer 22 are less likely to come into contact with moisture, gas contained in the air, and the like, and deterioration of the first wavelength conversion layer and the second wavelength conversion layer can be suppressed.

[0048] 8 is a schematic cross-sectional view showing a schematic configuration of a wavelength conversion member according to the seventh embodiment. In the wavelength conversion member 50, the second wavelength conversion layer 22 is formed in contact with the second intermediate layer 32, and the second wavelength conversion layer 22 and the second light-transmissive member 42 are bonded via a third adhesive layer 57. The second wavelength conversion layer 22 and the second light-transmissive member 42 may be bonded directly to each other without the third adhesive layer 57.

[0049] 9 is a schematic cross-sectional view showing a schematic configuration of a wavelength conversion member according to the eighth embodiment. The wavelength conversion member 50 includes, between the first light-transmissive member 41 and the second light-transmissive member 42, a first intermediate layer 31, a first wavelength conversion layer 21, a second intermediate layer 32, a second wavelength conversion layer 22, and a third adhesive layer 57, in that order from the first light-transmissive member 41 side. The wavelength conversion member according to the eighth embodiment includes, between the first light-transmissive member 41 and the third adhesive layer 57, a sealing layer 59 that covers the side surfaces of the first intermediate layer 31, the first wavelength conversion layer 21, the second intermediate layer 32, and the second wavelength conversion layer 22. The sealing layer 59 can be made of the same material as the sealing layer described above. The sealing layer 59 and the third adhesive layer 57 may be in contact with each other and integrated.

[0050] Second phosphor It is preferable that the second phosphor contained in the second wavelength conversion layer has at least one emission peak wavelength in the range of 600 nm or more and 670 nm or less when excited by light having an emission peak wavelength in the range of 380 nm or more and 500 nm or less.

[0051] The second phosphor may be, for example, (2a) a silicon nitride phosphor containing at least one element selected from Sr and Ca and Al in its composition and activated with Eu, (2b) an alkaline earth metal silicon nitride phosphor activated with Eu, or (2c) a phosphor containing K, Li, Na, Rb, Cs, and NH4 + and at least one selected from the group consisting of a Group 4 element , group 13 elements and Group 14 elements in its composition, and preferably contains at least one phosphor selected from the group consisting of Mn-activated fluoride phosphors and (2d) Mn-activated fluorogermanate phosphors, and may contain two or more phosphors.

[0052] (2a) Examples of silicon nitride phosphors that contain at least one element selected from Sr and Ca and Al in their composition and are activated with Eu include phosphors that contain a composition represented by the following formula (i): (Ca 1-s-t Sr s EU t ) x Al u S v N w (i) (In formula (i), s, t, u, v, w, and x are numbers satisfying 0≦s≦1.0, 0<t<1.0, 0<s + t<1.0, 0.8≦x≦1.0, 0.8≦u≦1.2, 0.8≦v≦1.2, 1.9≦u + v≦2.1, and 2.5≦w≦3.5, respectively.). The phosphor containing the composition represented by formula (i) may be represented as a CaAlSiN3:Eu phosphor or a (Sr,Ca)AlSiN3:Eu phosphor. In this specification, in the formula representing the composition of the phosphor, a plurality of elements described separated by a comma (,) means that the composition contains at least one of these plurality of elements. Further, in this specification, in the formula representing the composition of the phosphor, before the colon (:) represents the elements constituting the host crystal and their molar ratios, and after the colon (:) represents the activating element.)

[0053] (2b) Examples of the alkaline earth metal silicon nitride-based phosphor activated with Eu include a phosphor containing a composition represented by the following formula (ii). (Ca 1-p-q-r Sr p Ba q Eu r )2Si5N8 (ii) In formula (ii), p, q, and r satisfy 0≦p≦1.0, 0≦q≦1.0, 0<r<1.0, and p + q + r≦1.0.

[0054] (2c) A fluoride phosphor containing at least one element selected from the group consisting of K, Li, Na, Rb, Cs, and NH4 and at least one element selected from the group consisting of a Group 4 element, a Group 13 element, and a Group 14 element and activated with Mn includes a phosphor containing a composition represented by the following formula (iii). + Examples of the fluoride phosphor containing at least one element selected from the group consisting of K, Li, Na, Rb, Cs, and NH4 and at least one element selected from the group consisting of a Group 4 element, a Group 13 element, and a Group 14 element and activated with Mn include a phosphor containing a composition represented by the following formula (iii). A2[M 1 1-g Mn 4+ g F6] (iii) In formula (iii), A is at least one element selected from the group consisting of K, Li, Na, Rb, Cs, and NH4 + and is, for example, an element containing at least K. M 1is at least one element selected from the group consisting of Group 4 elements, Group 13 elements, and Group 14 elements, and examples thereof include Si and Al. g satisfies 0 < g < 0.2.

[0055] (2d) The fluorogermanate phosphor activated by Mn includes a phosphor having a composition represented by the following formula (iv). (i-j)MgO·(j / 2)Sc2O3·kMgF2·mCaF2·(1-n)GeO2·(n / 2)M 3 2O3:zMn 4+ (iv) In formula (iv), M 3 is at least one selected from the group consisting of Al, Ga, and In, and i, j, k, m, n, and z each satisfy 2 ≤ i ≤ 4, 0 ≤ j < 0.5, 0 < k < 1.5, 0 ≤ m < 1.5, 0 < n < 0.5, and 0 < z < 0.05.

[0056] When the second phosphor is a phosphor having an emission peak wavelength in the range of 600 nm or more and 670 nm or less when excited by light having an emission peak wavelength in the range of 380 nm or more and 500 nm or less, specifically, as the second phosphor, a fluoride phosphor represented by K2(Si,Al)F6:Mn, 3.5MgO·0.5MgF2·GeO2:Mn 4+ and other magnesium fluorogermanate phosphors represented by, Ca2Si5N8:Eu, (Ba,Sr)2Si5N8:Eu, (Sr,Ca)AlSiN3:Eu, CaAlSiN3:Eu, SrLiAl3N4:Eu, etc. The second phosphor has a narrow full width at half maximum in the emission spectrum of 10 nm or less, high color purity, and excellent color reproducibility. (2c) At least one selected from the group consisting of K, Li, Na, Rb, Cs, and NH4 + and at least one element selected from the group consisting of Group 4 elements , group 13 elements and at least one element selected from the group consisting of Group 14 elements are included in the composition, and it is preferable to use a fluoride phosphor activated by Mn. In addition to the above-mentioned phosphors, the second phosphor may contain cesium lead halide having a perovskite structure. That is, the second phosphor is CsPb(Br 1-x Ix )3 (0≦x<1.0), including cesium lead halide Cs4Pb(Br 1-x I x )6 (0≦x<1.0) and may contain cesium lead halide having a composition represented by the formula CsPb(Br 1-x I x A cesium lead halide having a composition represented by the formula (3) has at least one emission peak wavelength in the range of 600 nm or more and 670 nm or less when excited by light having an emission peak wavelength in the range of 380 nm or more and 500 nm or less.

[0057] The resin may be at least one selected from the group consisting of silicone resins, epoxy resins, acrylic resins, and modified resins thereof.

[0058] When the second wavelength conversion layer contains a resin, it preferably contains the second phosphor in a range of 1 part by mass to 50 parts by mass to 100 parts by mass of the resin, alternatively it may contain the second phosphor in a range of 2 parts by mass to 40 parts by mass to 3 parts by mass to 30 parts by mass to 100 parts by mass of the resin.

[0059] The thickness of the second wavelength conversion layer is preferably in the range of 0.1 μm to 500 μm, more preferably in the range of 0.2 μm to 300 μm.

[0060] In the wavelength conversion members according to the fifth to eighth embodiments, the third adhesive layer may be the same as the adhesive layer described above.

[0061] 10 is a schematic cross-sectional view showing a schematic configuration of a wavelength conversion member according to a ninth embodiment. The wavelength conversion member 50 includes a first light-transmissive member 41 and a second light-transmissive member 42, and includes, between the first light-transmissive member 41 and the second light-transmissive member 42, in this order from the first light-transmissive member 41 side, a first intermediate layer 31, a first wavelength conversion layer 21, a second intermediate layer 32, a second wavelength conversion layer 22, a third intermediate layer 33, and a third adhesive layer 57. The third intermediate layer 33 and the second light-transmissive member 42 may be directly bonded to each other without the third adhesive layer 57.

[0062] FIG. 11 is a schematic cross-sectional view showing a schematic configuration of a wavelength conversion member according to the tenth embodiment. The wavelength conversion member 50 includes, between the first light-transmissive member 41 and the second light-transmissive member 42, a first intermediate layer 31, a first wavelength conversion layer 21, a second intermediate layer 32, a second wavelength conversion layer 22, a third intermediate layer 33, and a third adhesive layer 57, in that order from the first light-transmissive member 41 side, and includes a sealing layer 59 around the periphery except for the third adhesive layer 57. The sealing layer 59 may be made of the same material as the sealing layer according to the fourth embodiment. The sealing layer 59 is preferably thick enough to cover the entire periphery of the first intermediate layer 31, the first wavelength conversion layer 21, the second intermediate layer 32, the second wavelength conversion layer 22, and the third intermediate layer 33 arranged between the first light-transmissive member and the second light-transmissive member. The sealing layer 59 and the third adhesive layer 57 may be in contact with each other and integrated. By providing the sealing layer 59, the surroundings of the first wavelength conversion layer 21 and the second wavelength conversion layer 22 are protected, making the first wavelength conversion layer 21 and the second wavelength conversion layer 22 less likely to come into contact with moisture or gases contained in the atmosphere, thereby suppressing deterioration of the first wavelength conversion layer and the second wavelength conversion layer.

[0063] In the wavelength conversion members according to the ninth and tenth embodiments, the third intermediate layer may be the same as the intermediate layer described above. The third adhesive layer may be the same as the first adhesive layer according to the first embodiment. The first wavelength conversion layer may be the same as the first embodiment. The second wavelength conversion layer may be the same as the fifth embodiment.

[0064] The wavelength conversion member may include a layered first light-transmissive member and a layered second light-transmissive member, and the wavelength conversion layer may include a first wavelength conversion layer including a first phosphor having a perovskite structure and a composition of ABX3, and a second wavelength conversion layer including a second phosphor having an emission peak wavelength in a wavelength range different from that of the first phosphor. The wavelength conversion member may include a first intermediate layer between the first light-transmissive member and the first wavelength conversion layer, a second intermediate layer on the second light-transmissive member side of the first wavelength conversion layer and between the first wavelength conversion layer and the second wavelength conversion layer, and a fourth adhesive layer having a thickness larger than that of the second wavelength conversion layer around the second wavelength conversion layer so that the second wavelength conversion layer does not come into contact with the second light-transmissive member. The wavelength conversion member preferably includes a second wavelength conversion layer having an area smaller than that of the second intermediate layer in order to arrange the fourth adhesive layer. By arranging a fourth adhesive layer having a thickness greater than that of the second wavelength conversion layer around the second wavelength conversion layer so that the second wavelength conversion layer does not come into contact with the second translucent member, the second wavelength conversion layer and the second translucent member do not come into contact, and reaction between the second phosphor, which is a phosphor having a perovskite structure contained in the second wavelength conversion layer, and the resin contained in the second translucent member is suppressed, thereby suppressing a decrease in the luminous intensity of the second phosphor.

[0065] 12 is a schematic cross-sectional view showing a schematic configuration of a wavelength conversion member according to the 11th embodiment. The wavelength conversion member 50 includes a first intermediate layer 31, a first wavelength conversion layer 21, a second intermediate layer 32, and a second wavelength conversion layer 22 between a first light-transmissive member 41 and a second light-transmissive member 42, in that order from the first light-transmissive member 41 side. , second wavelength A fourth adhesive layer 58 having a thickness greater than that of the second wavelength conversion layer 22 is provided around the conversion layer 22 so that the second wavelength conversion layer 22 does not contact the second light-transmissive member 42. The wavelength conversion member 50 preferably includes the second wavelength conversion layer 22 having an area smaller than that of the second intermediate layer 32 in order to arrange the fourth adhesive layer 58.

[0066] In the wavelength conversion member according to the 11th embodiment, the first wavelength conversion layer may be the same as that in the first embodiment, and the second wavelength conversion layer may be the same as that in the fifth embodiment.

[0067] The fourth adhesive layer may be made of the same material as the above-mentioned adhesive layer. Specifically, the thickness of the fourth adhesive layer may be in the range of 100 nm to 18 μm, or in the range of 200 nm to 17 μm.

[0068] Method for manufacturing wavelength conversion member The method for producing a wavelength conversion member includes a step of forming a first intermediate layer on a surface of a first light-transmissive member containing a resin, and a step of forming a first wavelength conversion layer containing a first phosphor having a perovskite structure and having a composition of ABX3 on the surface of the first intermediate layer. FIG. 13 is a flowchart showing a first embodiment of the method for producing a wavelength conversion member. The method for producing a wavelength conversion member of the first embodiment includes a step S101 of forming a first intermediate layer on the surface of the first light-transmissive member, and a step S102 of forming a first wavelength conversion layer on the surface of the first intermediate layer. The method for producing a wavelength conversion member may include a step of preparing a first light-transmissive member.

[0069] First light-transmissive member or a step of preparing a first light-transmissive member 1st transparent light The first light-transmitting member may be the same as the light-transmitting member used in the wavelength conversion member described above.

[0070] Steps of forming first to third intermediate layers The first to third intermediate layers (hereinafter also referred to as "intermediate layers") are preferably made of at least one oxide selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, magnesium oxide, titanium oxide, cerium oxide, zinc oxide, and tin oxide. The intermediate layer is preferably formed on the surface of the first light-transmitting member or the surface of the wavelength conversion layer by using a vapor deposition method or a sputtering method with an oxide as a raw material. The vapor deposition method may be either a physical vapor deposition method or a chemical vapor deposition method. Examples of the physical vapor deposition method include an electron beam vapor deposition method, a resistance heating vapor deposition method, and an ion plating method. Examples of the chemical vapor deposition method include a chemical vapor deposition method (CVD: Chemical Vapor Deposition) method. In the sputtering method, gas particles are collided with a target raw material, and the raw material that is blown off by the impact is deposited on the surface of the member to form the first intermediate layer. The intermediate layer is preferably formed by any of the electron beam vapor deposition method, the resistance heating vapor deposition method, the ion plating method, and the sputtering method. By forming the intermediate layer using these methods, an intermediate layer with a stable composition and a substantially uniform thickness can be formed on the surface of the light-transmitting member or the surface of the wavelength conversion layer in a relatively short time.

[0071] When the intermediate layer is formed by sputtering, a voltage of 50 V or more and 1000 V or less can be applied between the electrodes at room temperature in an argon atmosphere to form the first intermediate layer.

[0072] Forming a first wavelength conversion layer The first wavelength conversion layer can be formed by depositing raw materials constituting the composition of a phosphor having a perovskite structure and a composition of ABX3 on the surface of the intermediate layer by a vapor deposition method. The vapor deposition method can be either physical vapor deposition or chemical vapor deposition. Examples of physical vapor deposition methods include resistance heating vapor deposition. Among resistance heating vapor deposition methods, it is preferable to perform vapor deposition by electron bombardment vapor deposition. The electron bombardment vapor deposition method is a method in which an electron beam is irradiated onto a crucible filled with an evaporation source to indirectly evaporate the evaporation source and deposit it on the target object. The electron bombardment vapor deposition method reduces damage from reflected X-rays and improves film quality and adhesion compared to a method in which an electron beam is directly irradiated onto an evaporation source, such as the electron beam vapor deposition method. When the phosphor having a perovskite structure and a composition of ABX3 is cesium lead halide, it is preferable to manufacture the wavelength conversion layer by using a physical vapor deposition method. It is preferable to form the first wavelength conversion layer containing a phosphor made of cesium lead halide having a perovskite structure and a composition of ABX3 by a physical vapor deposition method, since this results in a first wavelength conversion layer that has high luminous efficiency and does not contain resin.

[0073] When the phosphor having a perovskite structure and a composition of ABX3 contained in the first wavelength conversion layer is, for example, cesium bromide lead, cesium bromide and lead bromide can be used as the material for forming the first wavelength conversion layer. For example, as the material for forming the first wavelength conversion layer, cesium bromide (CsBr) and lead bromide (PbBr2) are preferably used in a deposition rate ratio range of 1:1 to 10:1. They may be used in a range of 2:1 to 9:1, or may be used in a range of 3:1 to 8:1. The cesium halide is preferably cesium bromide. The lead halide is preferably lead bromide. Specifically, the first wavelength conversion layer is manufactured by using cesium bromide and lead bromide as raw materials in a rate ratio range of 1:1 to 10:1 by physical vapor deposition. When the phosphor having a perovskite structure and a composition ABX3 contained in the first wavelength conversion layer is cesium lead bromide, the cesium lead bromide having a perovskite structure and a composition ABX3 contained in the first wavelength conversion layer may have a composition in which some of the bromine is replaced by fluorine, chlorine or iodine.

[0074] When manufacturing the wavelength conversion member according to the first embodiment described above, it is sufficient to provide the first intermediate layer and the first translucent member only on one side of the first wavelength conversion layer. When manufacturing the wavelength conversion member according to the second embodiment described above, it is possible to provide the first intermediate layer and the first translucent member on one side of the first wavelength conversion layer, and provide the second intermediate layer and the second translucent member on the side of the first wavelength conversion layer opposite to the first intermediate layer.

[0075] The method for producing a wavelength conversion member may include a step of forming a second intermediate layer on the surface of the wavelength conversion layer, and a step of bonding the second intermediate layer and the second light-transmissive member. Fig. 14 is a flowchart showing a second embodiment of the method for producing a wavelength conversion member. The method for producing a wavelength conversion member of the second embodiment includes a step S201 of forming a first intermediate layer on the surface of the first light-transmissive member, a step S202 of forming a wavelength conversion layer on the surface of the first intermediate layer, a step S203 of forming a second intermediate layer on the surface of the wavelength conversion layer, and a step S204 of bonding the second intermediate layer and the second light-transmissive member.

[0076] A step of joining the second intermediate layer and the second light-transmitting member The method for producing a wavelength conversion member preferably includes a step of bonding the second intermediate layer and the second light-transmitting member. In the step of bonding the second intermediate layer and the second light-transmitting member, the second intermediate layer and the second light-transmitting member are preferably bonded via a first adhesive layer. The adhesive layer may be formed on the second intermediate layer or on the second light-transmitting member. The first adhesive layer preferably contains at least one resin selected from the group consisting of polyester resins, acrylic resins, acrylic urethane resins, polyester acrylate resins, polyurethane acrylate resins, epoxy acrylate resins, and urethane resins, and may contain two or more resins. The first adhesive layer is formed by applying a first adhesive layer composition containing the above-mentioned resin to one surface of the second intermediate layer or the second light-transmitting member. The method for applying the first adhesive layer composition can be a known method such as a knife coating method, a roll coating method, a bar coating method, a blade coating method, a roll coating method, a die coating method, or a gravure coating method. The thickness of the first adhesive layer may be within the range of 0.005 μm to 10 μm.

[0077] A wavelength conversion member may be formed having a first intermediate layer and a first translucent member on one side of the first wavelength conversion layer, or a wavelength conversion member according to a second embodiment may be formed having a first intermediate layer and a first translucent member on one side of the first wavelength conversion layer and a second intermediate layer and a second translucent member on the other side of the first wavelength conversion layer.

[0078] The manufacturing method of the wavelength conversion member may include a step of forming a sealing layer. Fig. 15 is a flowchart showing a third embodiment of the manufacturing method of the wavelength conversion member. The manufacturing method of the wavelength conversion member of the third embodiment may include a step S301 of forming a first intermediate layer on a surface of a first light-transmissive member, a step S302 of forming a first wavelength conversion layer on the surface of the first intermediate layer, and a step S303 of forming a second intermediate layer on the surface of the first wavelength conversion layer, and may include a step S304 of forming a sealing layer around the first intermediate layer, the first wavelength conversion layer, and the second intermediate layer, and a step S305 of bonding the second intermediate layer and the sealing layer to the second light-transmissive member.

[0079] When forming a sealing layer, it is preferable that the first intermediate layer, the first wavelength conversion layer, and the second intermediate layer are formed so as to have an area smaller than that of the first light-transmitting member and the second light-transmitting member. When forming a sealing layer apart from the first intermediate layer, the first wavelength conversion layer, and the second intermediate layer, it is preferable to cover the first intermediate layer, the first wavelength conversion layer, and the second intermediate layer with a cover member or the like, and then apply a sealing layer composition around the first intermediate layer, the first wavelength conversion layer, and the second intermediate layer to form a sealing layer. After forming the sealing layer, it is preferable to remove the cover member. When forming a sealing layer in contact with the first intermediate layer, the first wavelength conversion layer, and the second intermediate layer, it is preferable to apply a sealing layer composition directly around the first intermediate layer, the first wavelength conversion layer, and the second intermediate layer to form a sealing layer. After forming the sealing layer, it is also possible to apply a first adhesive layer composition to the top surface of the sealing layer and one surface of the second intermediate layer that is to be the second light-transmitting member side, and bond the second intermediate layer and the sealing layer to the second light-transmitting member via the first adhesive layer.

[0080] The method for producing a wavelength conversion member may include a step of forming a second adhesive layer having a thickness greater than that of the first wavelength conversion layer around the first wavelength conversion layer on the surface of the first intermediate layer, and a step of bonding a second translucent member to the second adhesive layer. Fig. 16 is a flowchart showing a fourth embodiment of the method for producing a wavelength conversion member. The method for producing a wavelength conversion member of the fourth embodiment may include a step S401 of forming a first intermediate layer on the surface of the first translucent member, a step S402 of forming a first wavelength conversion layer on the surface of the first intermediate layer, a step S403 of forming a second adhesive layer having a thickness greater than that of the first wavelength conversion layer around the first wavelength conversion layer on the surface of the first intermediate layer, and a step S404 of bonding the second adhesive layer to the second translucent member.

[0081] Forming a second adhesive layer The first wavelength conversion layer formed on the surface of the first intermediate layer is preferably formed to have an area smaller than that of the first intermediate layer in order to form a second adhesive layer around the first wavelength conversion layer. The second adhesive layer is preferably formed by covering the wavelength conversion layer formed on the first intermediate layer with a cover member or the like, and then applying a composition for the second adhesive layer by a known method, similar to the first adhesive layer described above, so as to have a thickness greater than that of the wavelength conversion layer. After forming the second adhesive layer, it is preferable to remove the cover member. The second adhesive layer is preferably formed using a composition for the second adhesive layer containing the same resin as the first adhesive layer described above.

[0082] The method for producing a wavelength conversion member includes a step of forming a second wavelength conversion layer when producing a wavelength conversion member including a second wavelength conversion layer containing a second phosphor having a perovskite structure and having an emission peak wavelength in a wavelength range different from that of the phosphor having an ABX3 composition included in the first wavelength conversion layer, as in the wavelength conversion members according to the fifth to eleventh embodiments. The method for producing a wavelength conversion member includes a step of forming a first intermediate layer on a surface of a first light-transmissive member containing a resin, a step of forming a first wavelength conversion layer containing a first phosphor, the first phosphor having a perovskite structure and having an ABX3 composition, on the surface of the first intermediate layer, a step of forming a second intermediate layer on the surface of the first wavelength conversion layer, and a step of forming a second wavelength conversion layer containing a second phosphor having an emission peak wavelength in a wavelength range different from that of the first phosphor, on the surface of the second intermediate layer. Process It is preferred that it includes

[0083] 17 is a flowchart showing a fifth embodiment of the method for producing a wavelength conversion member. The method for producing a wavelength conversion member of the fifth embodiment includes a step S501 of forming a first intermediate layer on a surface of a first light-transmissive member, a step S502 of forming a first wavelength conversion layer on the surface of the first intermediate layer, a step S503 of forming a second intermediate layer on the surface of the first wavelength conversion layer, and a step S504 of forming a second wavelength conversion layer on the surface of the second intermediate layer. The method for producing a wavelength conversion member may include a step of preparing a first light-transmissive member. In the method for producing a wavelength conversion member according to the fifth embodiment, the first intermediate layer, the first wavelength conversion layer, and the second intermediate layer can be produced in the same manner as in the method for producing a wavelength conversion member of the second embodiment.

[0084] Forming a second wavelength conversion layer When the second phosphor contained in the second wavelength conversion layer is a second phosphor having a perovskite structure with an emission peak wavelength in a wavelength range different from that of the first phosphor, the second wavelength conversion layer can be formed by depositing the raw material constituting the composition of the second phosphor having a perovskite structure on the surface of the second intermediate layer by a vapor deposition method, similar to the first phosphor. When the second phosphor contained in the second wavelength conversion layer is cesium lead halide having a perovskite structure, it is preferable to form the second wavelength conversion layer by a vapor deposition method. The vapor deposition method for forming the second wavelength conversion layer can be the same as that for forming the first wavelength conversion layer. When the phosphor having a perovskite structure contained in the second wavelength conversion layer is cesium lead halide, cesium halide and lead halide can be used as the wavelength conversion layer forming material. When the phosphor having a perovskite structure contained in the second wavelength conversion layer is, for example, cesium lead iodide, cesium iodide and lead iodide can be used as the second wavelength conversion layer forming material.

[0085] When the second phosphor contained in the second wavelength conversion layer is in a powder form, the powdered second phosphor can be mixed with a resin to produce a composition for a second wavelength conversion layer for forming the second wavelength conversion layer, and the composition for a second wavelength conversion layer can be used to form the second wavelength conversion layer. The resin contained in the second wavelength conversion layer can be at least one selected from the group consisting of silicone resin, modified silicone resin, and epoxy resin. The second phosphor contained in the composition for a second wavelength conversion layer can be in a range of 1 part by mass to 50 parts by mass, 2 parts by mass to 40 parts by mass, or 3 parts by mass to 30 parts by mass, relative to 100 parts by mass of the resin. Examples of methods for forming the second wavelength conversion layer using the composition for a second wavelength conversion layer include a printing method and a compression molding method. When the second wavelength conversion layer is formed by a printing method, the composition for a second wavelength conversion layer for forming the second wavelength conversion layer is applied to the surface of the second intermediate layer or the second light-transmitting member by a printing method and cured. The second wavelength conversion layer may be formed on the surface of the second intermediate layer or on the surface of the second light-transmitting member. When the second wavelength conversion layer is formed by compression molding, the composition for the second wavelength conversion layer is placed in a mold and the resin is cured to form the second wavelength conversion layer. As in the wavelength conversion member according to the fifth or sixth embodiment, the second wavelength conversion layer may be bonded to the second intermediate layer via a third adhesive layer. As in the wavelength conversion member according to the seventh or eighth embodiment, the second wavelength conversion layer may be bonded to the second light-transmitting member via a third adhesive layer.

[0086] The method for manufacturing the wavelength conversion member may include a step of forming a sealing layer around a member disposed between the first light-transmissive member and the second light-transmissive member. When forming the wavelength conversion member according to the sixth embodiment, the method may include a step of forming a sealing layer around the first intermediate layer, the first wavelength conversion layer, the second intermediate layer, the third adhesive layer, and the second wavelength conversion layer, and a step of bonding a top surface of the sealing layer to the second light-transmissive member, after the step of forming the second wavelength conversion layer. When forming the sealing layer, it is preferable that the first intermediate layer, the first wavelength conversion layer, the second intermediate layer, the third adhesive layer, and the second wavelength conversion layer are formed so as to have an area smaller than the areas of the first light-transmissive member and the second light-transmissive member. When the sealing layer is formed apart from the first intermediate layer, the first wavelength conversion layer, the second intermediate layer, the third adhesive layer, and the second wavelength conversion layer, it is preferable to cover the first intermediate layer, the first wavelength conversion layer, the second intermediate layer, the third adhesive layer, and the second wavelength conversion layer with a cover member or the like, and then apply a sealing layer composition around the first intermediate layer, the first wavelength conversion layer, the second intermediate layer, the third adhesive layer, and the second wavelength conversion layer to form the sealing layer. After the sealing layer is formed, it is preferable to remove the cover member. When the sealing layer is formed in contact with the first intermediate layer, the first wavelength conversion layer, the second intermediate layer, the third adhesive layer, and the second wavelength conversion layer, it is also possible to form the sealing layer by applying the sealing layer composition directly around the first intermediate layer, the first wavelength conversion layer, the second intermediate layer, the third adhesive layer, and the second wavelength conversion layer. After the sealing layer is formed, the top surface of the sealing layer and the second light-transmitting member may be joined.

[0087] When forming the wavelength conversion member according to the eighth embodiment, the process may include, after the process of forming the second wavelength conversion layer, a process of forming a sealing layer around the first intermediate layer, the first wavelength conversion layer, the second intermediate layer and the second wavelength conversion layer, and a process of bonding the top surface of the sealing layer to the second translucent member. The sealing layer can be formed by the same method as in the case of manufacturing the wavelength conversion member according to the sixth embodiment. After forming the sealing layer, a sealing layer is bonded to the top surface of the sealing layer and the surface of the second wavelength conversion layer that faces the second translucent member. 3rd contact The second wavelength-converting layer and the sealing layer may be bonded to the second light-transmissive member via a third adhesive layer by applying a layering composition.

[0088] The method for producing a wavelength conversion member includes the steps of: The conversion layer is When the first wavelength conversion layer contains a second phosphor having a perovskite structure and having an emission peak wavelength in a different wavelength range from the first phosphor having a composition of ABX3, it is preferable to include a step of forming a third intermediate layer on the surface of the second wavelength conversion layer and a step of joining the third intermediate layer to the second translucent member.

[0089] 18 is a flowchart showing a sixth embodiment of the method for producing a wavelength conversion member. The method for producing a wavelength conversion member of the sixth embodiment includes a step S601 of forming a first intermediate layer on a surface of a first light-transmissive member, a step S602 of forming a first wavelength conversion layer on a surface of the first intermediate layer, a step S603 of forming a second intermediate layer on a surface of the first wavelength conversion layer, a step S604 of forming a second wavelength conversion layer on a surface of the second intermediate layer, a step S605 of forming a third intermediate layer on a surface of the second wavelength conversion layer, and a step S606 of bonding the third intermediate layer to the second light-transmissive member. The method for producing a wavelength conversion member may include a step of preparing a first light-transmissive member, and the first intermediate layer, the first wavelength conversion layer, and the second intermediate layer can be produced in the same manner as the method for producing a wavelength conversion member of the first embodiment.

[0090] A step of joining the third intermediate layer and the second light-transmitting member The method for manufacturing the wavelength conversion member preferably includes a step of bonding the third intermediate layer and the second light-transmissive member. In the step of bonding the third intermediate layer and the second light-transmissive member, the third intermediate layer and the second light-transmissive member are preferably bonded via a third adhesive layer. The third adhesive layer may be formed on the third intermediate layer or on the second light-transmissive member. The third adhesive layer can be manufactured using the same material and method as the first adhesive layer. The thickness of the third adhesive layer can be within a range of 0.005 μm to 10 μm.

[0091] The method for manufacturing the wavelength conversion member may include a step of forming a sealing layer around a member disposed between the first light-transmissive member and the second light-transmissive member. When forming the wavelength conversion member according to the tenth embodiment, the method may include a step of forming a sealing layer around the first intermediate layer, the first wavelength conversion layer, the second intermediate layer, the second wavelength conversion layer, and the third intermediate layer, and a step of bonding a top surface of the sealing layer to the second light-transmissive member, after the step of forming the third intermediate layer. When forming the sealing layer, it is preferable that the first intermediate layer, the first wavelength conversion layer, the second intermediate layer, the second wavelength conversion layer, and the third intermediate layer are formed so as to have an area smaller than the areas of the first light-transmissive member and the second light-transmissive member. When the sealing layer is formed apart from the first intermediate layer, the first wavelength conversion layer, the second intermediate layer, the second wavelength conversion layer, and the third intermediate layer, it is preferable to cover the first intermediate layer, the first wavelength conversion layer, the second intermediate layer, the second wavelength conversion layer, and the third intermediate layer with a cover member or the like, and then apply a sealing layer composition to the periphery of the first intermediate layer, the first wavelength conversion layer, the second intermediate layer, the second wavelength conversion layer, and the third intermediate layer to form the sealing layer. After the sealing layer is formed, it is preferable to remove the cover member. When the sealing layer is formed in contact with the first intermediate layer, the first wavelength conversion layer, the second intermediate layer, the second wavelength conversion layer, and the third intermediate layer, it is also possible to form the sealing layer by applying the sealing layer composition directly to the periphery of these members. After the sealing layer is formed, a third adhesive layer may be interposed between the third intermediate layer and the second translucent member to bond the top surfaces of the third intermediate layer and the sealing layer to the second translucent member.

[0092] The method for producing a wavelength conversion member may include a step of forming a fourth adhesive layer having a thickness greater than that of the second wavelength conversion layer around the second wavelength conversion layer on the surface of the second intermediate layer, and a step of bonding a second translucent member to the fourth adhesive layer. Fig. 19 is a flowchart showing a seventh embodiment of the method for producing a wavelength conversion member. The method for producing a wavelength conversion member of the seventh embodiment preferably includes a step S701 of forming a first intermediate layer on the surface of the first translucent member, a step S702 of forming a first wavelength conversion layer on the surface of the first intermediate layer, a step S703 of forming a second intermediate layer on the surface of the first wavelength conversion layer, a step S704 of forming a second wavelength conversion layer on the surface of the second intermediate layer, a step S705 of forming a fourth adhesive layer having a thickness greater than that of the second wavelength conversion layer around the second wavelength conversion layer on the surface of the second intermediate layer, and a step S706 of bonding the fourth adhesive layer to the second translucent member.

[0093] Step of forming a fourth adhesive layer The second wavelength conversion layer formed on the surface of the second intermediate layer is preferably formed to have an area smaller than that of the second intermediate layer in order to form a fourth adhesive layer around the second wavelength conversion layer. The fourth adhesive layer is preferably formed by covering the second wavelength conversion layer formed on the second intermediate layer with a cover member or the like, and then applying a composition for the fourth adhesive layer by a known method, similar to the first adhesive layer described above, so as to have a thickness greater than that of the second wavelength conversion layer. After forming the fourth adhesive layer, it is preferable to remove the cover member. The fourth adhesive layer is preferably formed using a composition for the fourth adhesive layer containing the same resin as the first adhesive layer described above.

[0094] Light-emitting device The light emitting device includes the wavelength conversion member described above and an excitation light source. The wavelength conversion member may be any of the wavelength conversion members according to the first to eleventh embodiments described above.

[0095] The light emitting device will be described below. Fig. 20 is a schematic cross-sectional view of the light emitting device according to the first embodiment. Fig. 21 is a schematic perspective view of the light emitting device according to the first embodiment.

[0096] The light emitting device 100 according to the first embodiment can be used in the image display device according to the first embodiment described below.

[0097] The light emitting device 100 includes a light emitting element 10 serving as an excitation light source, and a wavelength conversion member 50 according to the second embodiment. The wavelength conversion member 50 includes a wavelength conversion layer 20 having a perovskite structure and containing a phosphor having a composition of ABX3, a first intermediate layer 31 and a first light transmissive member 41 on one surface side of the wavelength conversion layer 20, and a second intermediate layer 32 and a second light transmissive member 42 on the other surface side of the wavelength conversion layer 20. The light emitting element 10 is flip-chip mounted on wiring 91 of a substrate 90 via a conductive member 60. The substrate 90 includes wiring 91 and a base 92 having the wiring 91. The wavelength conversion member 50 is large enough to cover the entire surface of the light emitting element 10 in a front view. A light incident surface 50a of the wavelength conversion member 50 is bonded to one surface of the light emitting element 10 via a light guiding member 80. The covering member 70 is formed on the substrate 90, covers the side surfaces of the conductive member 60, the light emitting element 10, the light guiding member 80, and the wavelength conversion member 50, and surrounds the entire periphery of the conductive member 60, the light emitting element 10, the light guiding member 80, and the wavelength conversion member 50. The front surface of the wavelength conversion member 50 and the front surface of the covering member 70 form substantially the same plane.

[0098] The wavelength conversion member 50 according to the second embodiment includes a first intermediate layer 31 and a first light-transmissive member 41, and a second intermediate layer 32 and a second light-transmissive member 42, respectively, on both sides of the wavelength conversion layer 20, and a first adhesive layer 55 is interposed between the second intermediate layer 32 and the second light-transmissive member 42. This protects the wavelength conversion layer. Although the light emitting device according to the first embodiment has been described as using the wavelength conversion member 50 according to the second embodiment, the wavelength conversion member 50 according to the first embodiment may also be used. The wavelength conversion member 50 according to the first embodiment includes a first intermediate layer 30 and a light-transmissive member 40 on one side of the wavelength conversion layer 20.

[0099] Light emitting element A light-emitting element includes at least a semiconductor device structure and often includes a substrate. An example of a light-emitting element is an LED chip.

[0100] The light emitting element can have an emission peak wavelength selected from the ultraviolet region to the infrared region depending on the semiconductor material and its mixed crystal ratio. As the semiconductor material, it is preferable to use a nitride semiconductor capable of emitting light of a short wavelength capable of efficiently exciting the phosphor. From the viewpoints of luminous efficiency, excitation of the phosphor and the color mixing relationship with the emission, the emission peak wavelength of the light emitting element is in the range of 380 nm to 500 nm, preferably in the range of 400 nm to 480 nm, and more preferably in the range of 420 nm to 475 nm.

[0101] substrate The substrate is composed of at least a wiring and a base that holds the wiring. In addition, the substrate may include an insulating protective film such as a solder resist or a coverlay.

[0102] wiring The wiring is formed at least on the upper surface (front surface) of the base, and may also be formed inside and / or on the side and / or lower surface (rear surface) of the base. The wiring preferably has an element connection terminal portion on which the light emitting element is mounted, an external connection terminal portion connected to an external circuit, and a lead wiring portion connecting these terminal portions. The wiring may be formed of copper, iron, nickel, tungsten, chromium, aluminum, silver, gold, titanium, palladium, rhodium, or an alloy thereof.

[0103] base body If the substrate is a rigid substrate, it can be made of resin or fiber-reinforced resin, ceramics, glass, metal, paper, etc. Examples of resin or fiber-reinforced resin include epoxy, glass epoxy, bismaleimide triazine, polyimide, etc.

[0104] Conductive Materials As the conductive member, at least one of the following can be used: bumps of gold, silver, copper, etc.; metal pastes containing metal powders of silver, gold, copper, platinum, aluminum, palladium, etc. and resin binders; solders such as tin-bismuth, tin-copper, tin-silver, and gold-tin; and brazing materials such as low-melting point metals.

[0105] Light guide member The light guide member is a member that bonds the light emitting element and the wavelength conversion member and guides light from the light emitting element to the wavelength conversion member. Examples of the base material of the light guide member include silicone resin, epoxy resin, phenol resin, polycarbonate resin, acrylic resin, and modified resins thereof.

[0106] Covering material From the viewpoint of forward light extraction efficiency, the covering member preferably has a light reflectance of 70% or more at the emission peak wavelength of the light emitting element, more preferably 80% or more, and even more preferably 90% or more.

[0107] Resin for covering material Examples of the resin constituting the coating member include silicone resin, epoxy resin, phenol resin, polycarbonate resin, acrylic resin, and modified resins thereof.

[0108] White pigment The white pigment may be one selected from the group consisting of titanium oxide, zinc oxide, magnesium oxide, magnesium carbonate, magnesium hydroxide, calcium carbonate, calcium hydroxide, calcium silicate, magnesium silicate, barium titanate, barium sulfate, aluminum hydroxide, aluminum oxide, and zirconium oxide, either alone or in combination.

[0109] Method for manufacturing a light emitting device The light emitting device can be manufactured by the method described in JP 2017-188592 A.

[0110] A light emitting device according to a second embodiment will be described below. Fig. 22 is a schematic cross-sectional view of the light emitting device according to the second embodiment. Fig. 23 is a schematic plan view of the light emitting device according to the second embodiment. The light emitting device 200 according to the second embodiment is a top-emitting type. The top-emitting type light emitting device can be used in the image display device according to the second embodiment described later. In the light emitting device 200 according to the second embodiment, the same reference numerals are used for the members common to the light emitting device 100 according to the first embodiment. The light emitting device 200 according to the second embodiment uses a thin base material 93 of, for example, 500 μm or less, and a substrate 90 provided with wirings 91A and 91B. The wavelength conversion member 50 includes a wavelength conversion layer 20 having a perovskite structure and containing a phosphor having a composition of ABX3, a first intermediate layer 31 and a first translucent member 41 on one surface side of the wavelength conversion layer 20, and a second intermediate layer 32 and a second translucent member 42 on the other surface side of the wavelength conversion layer 20. In the wavelength conversion member 50, a first adhesive layer 55 is interposed between the second intermediate layer 32 and the second translucent member. The light incident surface of the wavelength conversion member 50 is joined to one surface of the light emitting element 10 via a light guiding member 80. The light emitting device 200 includes a substrate 90 including a thin base material 93, and the other members are the same as those of the light emitting device 100.

[0111] The manufacturing method of the light emitting device 200 is common to the manufacturing method of the light emitting device 100, and the manufacturing method of the light emitting device 200 may include a step of removing a part of the base material 93 to make the base material thinner.

[0112] For example, in a light-emitting device used in a backlight, a light-emitting element that emits blue light, a green phosphor that emits green light, and a red phosphor that emits red light can be used to produce a wide range of emitted colors.

[0113] Next, an image display device using the light emitting device according to the first embodiment or the light emitting device according to the second embodiment will be described.

[0114] Fig. 24 shows an image display device 300 according to the first embodiment. The image display device 300 according to the first embodiment includes a backlight device 160 and a display panel 170 arranged on the light output side of the backlight device 160. The image display device 300 has a display surface 300A for displaying an image. In the drawing, the surface of the display panel 170 serves as the display surface 300A.

[0115] The backlight device 160 illuminates the display panel 170 from the rear side in a planar manner.

[0116] Display Panel The display panel 170 is a liquid crystal display panel and includes a first polarizing sheet 140 arranged on the light incident side, a second polarizing sheet 150 arranged on the light exiting side, and a liquid crystal cell 145 arranged between the first polarizing sheet 140 and the second polarizing sheet 150.

[0117] Details of liquid crystal display panels are described in various publicly known documents (for example, "Encyclopedia of Flat Panel Displays (edited by Uchida Tatsuo and Uchiike Heiki)" published by the Industrial Research Institute in 2001), and further detailed explanation will not be given here.

[0118] Backlight Device The backlight device 160 is configured as an edge light type backlight device, and includes a housing 105, a light emitting device 110 arranged on the housing 105 or at a position separated from the housing 105, a light guide plate 115 arranged on the side of the light emitting device 110, a diffusion sheet 125 arranged on the light output side of the light guide plate 115, a sheet-like second wavelength conversion member 130 arranged on the diffusion sheet, and a prism sheet 135 arranged on the light output surface side of the sheet-like wavelength conversion member 130. A reflection sheet 120 is provided between the housing 105 and the light guide plate 115.

[0119] The backlight device 160 has a light emitting surface that emits light in a planar manner. In the drawing, the light exit surface of the prism sheet 135 is the light emitting surface of the backlight device 160.

[0120] The surface of the sheet-shaped second wavelength conversion member 130 facing the diffusion sheet 125 is a light incident surface, and the surface of the sheet-shaped second wavelength conversion member 130 facing the prism sheet 135 is a light exiting surface. The sheet-shaped second wavelength conversion member 130 may be the same wavelength conversion member as any of the wavelength conversion members according to the first to eleventh embodiments described above, or may be another wavelength conversion member.

[0121] Light-emitting device The light emitting device 110 is configured using a number of light emitting elements arranged linearly along one side of the side surface of the light guiding plate 115 on the light incident surface side of the light guiding plate 115. The light emitting device according to the first embodiment or the light emitting device according to the second embodiment described above can be used as the light emitting device 110. An additional light emitting device not provided with a wavelength conversion member may be further provided.

[0122] light guide plate Light guide plate 115 has a light exit surface constituted by one main surface on the display panel 170 side, a back surface constituted by the other main surface opposite the light exit surface, and side surfaces extending between the light exit surface and the back surface. The side surface on the light emitting device 110 side among the side surfaces serves as a light entrance surface that receives light from light emitting device 110. Light that enters light guide plate 115 from the light entrance surface is guided inside the optical plate in a direction connecting the light entrance surface and the opposite surface opposite the light entrance surface, and is emitted from the light exit surface.

[0123] Suitable materials for forming the light guide plate 115 include transparent resins mainly composed of one or more of acrylic resin, polystyrene, polycarbonate, polyethylene terephthalate, polyacrylonitrile, etc., and epoxy acrylate or urethane acrylate reactive resins (such as ionizing radiation curable resins).

[0124] Diffusion Sheet The diffusion sheet 125 has a function of diffusing the light emitted from the light output surface of the light guide plate 115 and making the light uniformly enter the sheet-shaped second wavelength conversion member 130. The diffusion sheet 125 uses a resin containing a light diffusing material or the like.

[0125] Prism Sheet The prism sheet 135 has a function of increasing the brightness of the light emitted from the sheet-shaped second wavelength converting member 130 .

[0126] Reflective sheet The reflective sheet 120 allows the light emitted from the light emitting device 110 to enter the light guide plate 115 and exit from the light exit surface side.

[0127] In this manner, the light emitted from the backlight device 160 enters the first polarizing sheet 140 provided on the display panel 170 and is emitted from the display surface 300A of the image display device.

[0128] Next, an image display device according to a second embodiment will be described with reference to the drawings. Figure 25 is a schematic cross-sectional view of an image display device showing a direct type backlight structure according to the second embodiment. The image display device 300E of the second embodiment includes a backlight device 160E and a display panel 170 arranged on the light output side of the backlight device 160E, and has a configuration similar to that of the display panel 170 described in the image display device of the first embodiment.

[0129] The backlight device 160E is configured as a direct type backlight device, and includes a light emitting device 110E, a housing 105E in which the light emitting device 110E is disposed, a diffusion sheet 125E disposed apart from the light emitting device 110E, a sheet-like second wavelength conversion member 130E disposed on the diffusion sheet, and a prism sheet 135E disposed on the light output side of the sheet-like second wavelength conversion member 130E. The light emitting device 110E may be the light emitting device according to the first embodiment or the light emitting device according to the second embodiment. A reflection sheet 120E is provided between the housing 105E and the light guide plate 115E.

[0130] Illumination equipment The light emitted from the device 110E enters the diffusion sheet 125E via the light guide plate 115E.

[0131] In this manner, the light emitted from the backlight device 160E enters the first polarizing sheet 140 provided on the display panel 170 and is emitted from the display surface 300A of the image display device. EXAMPLES

[0132] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0133] Example 1 A wavelength conversion member according to the first embodiment was formed (see FIG. 1). A single-layer first light-transmitting member made of polyethylene terephthalate was prepared. The first light-transmitting member had a thickness of 120 μm. Silicon dioxide (SiO2) was used as a raw material, and a first intermediate layer made of silicon dioxide (SiO2) and having a thickness of 100 nm was formed by sputtering at room temperature in an argon atmosphere using a magnetron sputtering device. Cesium bromide (CsBr) and lead bromide (PbBr2) were used as the raw materials for the phosphor, and a wavelength conversion layer containing 99% by mass or more of cesium lead bromide was formed by physical vapor deposition using a vapor deposition device at room temperature with a rate ratio in the range of 1:1 to 10:1. Cesium lead bromide was a phosphor that emits light when irradiated with excitation light in the wavelength range from ultraviolet light to visible light. It was confirmed that the cesium lead bromide contained in the wavelength conversion layer emits light when irradiated with visible light, and contains a phosphor having a composition represented by CsPbBr3 with a perovskite structure. Specifically, the wavelength conversion layer contained cesium lead bromide, a phosphor that emits light when irradiated with excitation light with an emission peak wavelength of 450 nm. A composition analysis of another wavelength conversion layer deposited under similar conditions was performed using an energy dispersive X-ray spectrometer (EDX, Oxford, accelerating voltage: 10 kV). It was confirmed that the phosphor having a composition expressed by CsPbBr3 accounted for approximately 10 mass% of the phosphor, and the phosphor having a composition expressed by Cs4PbBr6 accounted for approximately 90 mass%.

[0134] Comparative Example 1 A wavelength conversion member of Comparative Example 1, which did not have a first intermediate layer, was formed in the same manner as in Example 1, except that a wavelength conversion layer was formed on the surface of the first light-transmissive member without forming a first intermediate layer.

[0135] Comparative Example 2 A wavelength conversion member of Comparative Example 2, which did not have a first intermediate layer, was formed in the same manner as in Example 1, except that a wavelength conversion layer was formed on the surface of the first light-transmissive member, the first light-transmissive member including a gas barrier layer and a layer made of polyethylene terephthalate and in which a plurality of layers were laminated, without forming a first intermediate layer.

[0136] The wavelength conversion members of the examples and comparative examples were evaluated as follows. Each of the wavelength conversion members of the Examples and Comparative Examples was kept in an oven at 80° C. for 100 hours. The emission spectrum of each wavelength conversion member before it was placed in the oven and the emission spectrum of each wavelength conversion member kept in the oven at 80° C. for 100 hours were measured using a spectroradiometer (CL-500A, manufactured by Konica Minolta, Inc.). The emission intensity of the emission peak of each wavelength conversion material before being placed in the furnace was taken as 100%, and the percentage of decrease in the emission intensity of the emission peak of each wavelength conversion material after being held in the furnace at 80° C. for 100 hours was calculated. The results are shown in Table 1.

[0137] [Table 1]

[0138] The wavelength conversion member of Example 1 had a 14% decrease in emission intensity of the emission peak after being held in an oven at 80° C. for 100 hours, compared to 100% of the emission intensity of the emission peak of the wavelength conversion member before being placed in the oven. The wavelength conversion member of Example 1 has a first intermediate layer between the resin-containing translucent member and the wavelength conversion layer, and therefore the reaction between the phosphor having a perovskite structure and having an ABX3 composition contained in the wavelength conversion layer and the resin contained in the translucent member is suppressed, and a decrease in the emission intensity of the phosphor having a perovskite structure and having an ABX3 composition contained in the wavelength conversion layer is suppressed.

[0139] The wavelength conversion member of Comparative Example 1 had a 23% decrease in emission intensity of its emission peak after being held in an oven at 80° C. for 100 hours, compared to 100% of the emission intensity of the emission peak of the wavelength conversion member before it was placed in the oven. Since the wavelength conversion member of Comparative Example 1 does not have a first intermediate layer between the resin-containing translucent member and the wavelength conversion layer, it is presumed that heating at 80° C. for 100 hours caused a reaction between the phosphor having a perovskite structure and a composition of ABX3 contained in the wavelength conversion layer and the resin contained in the translucent member, changing the crystal structure of the phosphor contained in the wavelength conversion layer and decreasing the emission intensity.

[0140] The wavelength conversion member according to Comparative Example 2 had a 37% decrease in emission intensity of the emission peak after being held in an oven at 80° C. for 100 hours, compared to 100% of the emission intensity of the emission peak of the wavelength conversion member before being placed in the oven. Since the wavelength conversion member according to Comparative Example 2 does not have a first intermediate layer between the resin-containing translucent member and the wavelength conversion layer, even if the first translucent member has a multi-layer structure including a gas barrier layer, it is presumed that heating at 80° C. for 100 hours caused a reaction between the phosphor having a perovskite structure and a composition of ABX3 contained in the wavelength conversion layer and the resin contained in the translucent member, changing the crystal structure of the phosphor contained in the wavelength conversion layer and decreasing the emission intensity. [Industrial Applicability]

[0141] The embodiments of the present disclosure are useful for various lighting light sources, in-vehicle light sources, display light sources, and the like. In particular, they can be advantageously applied to backlight units of image display devices using liquid crystal. The light-emitting device according to the embodiments of the present disclosure is also advantageous for backlights for display devices of mobile devices. They can be used as light-emitting devices for general lighting and light-emitting devices for vehicles. [Explanation of symbols]

[0142] 10: light-emitting element, 20: wavelength conversion layer, 21: first wavelength conversion layer, 22: second wavelength conversion layer, 30: first intermediate layer, 31: first intermediate layer, 32: second intermediate layer, 33: third intermediate layer, 40: light-transmitting member, 41: first light-transmitting member, 42: second light-transmitting member, 43: first bonding layer, 44: first protective layer, 45: second bonding layer, 46: second protective layer, 47: gas barrier layer or water vapor barrier layer, 48: antistatic layer or third bonding layer, 50: wavelength conversion member, 55: first adhesive layer, 56: second adhesive layer, 57: third adhesive layer, 58: fourth adhesive layer, 59: sealing layer, 60: conductive member, 70: covering member, 80: light-guiding member, 90: substrate, 100, 200: light-emitting device, 105, 105E: housing, 110, 110E: light-emitting device, 115, 115E: light-guiding plate, 120, 120E: reflective sheet, 125, 125E: diffusion sheet, 130, 130E: sheet-like second wavelength conversion member, 135, 135E: prism sheet, 140: first polarizing sheet, 145: liquid crystal cell, 150: second polarizing sheet, 160, 160E: backlight device, 170: display panel, 300, 300E: image display device.

Claims

1. A transparent member containing a resin and a perovskite structure having a composition of ABX ３ a wavelength conversion layer that does not contain resin and that contains a first phosphor, and a first intermediate layer that contains a transparent inorganic oxide and is provided between the light-transmitting member and the wavelength conversion layer, The first intermediate layer is provided on a surface of the light-transmitting member, The wavelength conversion layer is provided on a surface of the first intermediate layer, the wavelength conversion layer has a perovskite structure and is formed by evaporating raw materials constituting a composition of a phosphor having a composition of ABX 3 on a surface of the first intermediate layer; Regarding the composition of the first phosphor, A is Rb ＋ , C.H. ３ N.H. ３ ＋ , and Cs ＋ and B is at least one cation selected from the group consisting of Pb ２＋ , and Sn ２＋ and X is at least one metal ion selected from the group consisting of F － , Cl － , B － , and I － The wavelength converting member is at least one anion selected from the group consisting of:

2. The wavelength conversion member according to claim 1 , wherein the first phosphor is a cesium lead halide.

3. The first phosphor is CsPbBr ３ Cs includes cesium lead halide having a composition represented by the formula: ４ PbBr ６ The wavelength conversion member according to claim 1 or 2, which may contain cesium lead halide having a composition represented by the following formula:

4. CsPbBr ３ The wavelength conversion member according to claim 3 , comprising 1 mass % or more and 50 mass % or less of cesium lead halide having a composition represented by the following formula with respect to a total amount of the first phosphor.

5. The wavelength conversion member according to claim 1 , wherein the wavelength conversion layer contains 99 mass % or more of cesium lead halide.

6. 6. The wavelength conversion member according to claim 1, wherein the first intermediate layer contains at least one oxide selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, magnesium oxide, titanium oxide, cerium oxide, zinc oxide, and tin oxide.

7. The wavelength conversion member according to claim 1 , wherein the wavelength conversion layer has a thickness in the range of 10 nm to 10 μm.

8. The wavelength conversion member according to claim 1 , wherein a thickness of the first intermediate layer is in a range of 0.001 to 1000 when a thickness of the wavelength conversion layer is taken as 1.

9. 9. The wavelength conversion member according to claim 1, wherein the light-transmitting member comprises a layered first light-transmitting member and a layered second light-transmitting member, the wavelength conversion layer is disposed between the first light-transmitting member and the second light-transmitting member, and comprises a second intermediate layer disposed on the second light-transmitting member side of the wavelength conversion layer.

10. 9. The wavelength conversion member according to claim 1, wherein the light-transmitting member comprises a layered first light-transmitting member and a layered second light-transmitting member, the wavelength conversion layer is disposed between the first light-transmitting member and the second light-transmitting member, and a second adhesive layer having a thickness larger than that of the wavelength conversion layer is provided around the wavelength conversion layer so that the wavelength conversion layer does not come into contact with the second light-transmitting member.

11. 9. The wavelength conversion member according to claim 1, wherein the translucent member comprises a layered first translucent member and a layered second translucent member, the wavelength conversion layer comprises a first wavelength conversion layer containing the first phosphor and a second wavelength conversion layer containing a second phosphor having an emission peak wavelength in a wavelength range different from that of the first phosphor, the first wavelength conversion layer and the second wavelength conversion layer are disposed between the first translucent member and the second translucent member and are on the second translucent member side of the first wavelength conversion layer, a second intermediate layer is disposed between the first wavelength conversion layer and the second wavelength conversion layer, and a third intermediate layer is disposed on the second translucent member side of the second wavelength conversion layer.

12. 9. The wavelength conversion member according to claim 1, wherein the light-transmitting member comprises a layered first light-transmitting member and a layered second light-transmitting member, the wavelength conversion layer comprises a first wavelength conversion layer containing the first phosphor and a second wavelength conversion layer containing a second phosphor having an emission peak wavelength in a wavelength range different from that of the first phosphor, the first wavelength conversion layer and the second wavelength conversion layer are disposed between the first light-transmitting member and the second light-transmitting member, the second intermediate layer is on the second light-transmitting member side of the first wavelength conversion layer, and is disposed between the first wavelength conversion layer and the second wavelength conversion layer, and a fourth adhesive layer having a thickness greater than that of the second wavelength conversion layer and disposed around the second wavelength conversion layer so that the second wavelength conversion layer does not come into contact with the second light-transmitting member.

13. 13. The wavelength conversion member according to claim 9, wherein the first light-transmissive member or the second light-transmissive member has a thickness in the range of 5 μm to 500 μm.

14. The second phosphor is CsPb(Br １－ｘ I ｘ ) ３ Cesium lead halide having a composition represented by the formula (0≦x<1.0) is included, Cs ４ Pb(Br １－ｘ I ｘ ) ６ The wavelength conversion member according to claim 11 or 12, which may contain cesium lead halide having a composition represented by (0≦x<1.0).

15. The second phosphor is CsPb(Br １－ｘ I ｘ ) ３ The wavelength conversion member according to claim 14 , comprising 1 mass % or more and 50 mass % or less of cesium lead halide having a composition represented by (0≦x<1.0).

16. A light emitting device comprising: the wavelength conversion member according to claim 1 ; and an excitation light source.

17. forming a first intermediate layer containing a transparent inorganic oxide on a surface of a first light-transmissive member containing a resin; A raw material constituting a composition of a phosphor having a perovskite structure and a composition of ABX 3 is deposited on the surface of the first intermediate layer by a vapor deposition method to form a phosphor having a perovskite structure and a composition of ABX 3 . ３ and forming a first wavelength conversion layer containing a first phosphor and not containing resin, Regarding the composition of the first phosphor, A is Rb ＋ , C.H. ３ N.H. ３ ＋ , and Cs ＋ and B is at least one cation selected from the group consisting of Pb ２＋ , and Sn ２＋ and X is at least one metal ion selected from the group consisting of F － , Cl － , B － , and I － The method for producing a wavelength conversion member, wherein the anion is at least one type of anion selected from the group consisting of:

18. forming a second intermediate layer on a surface of the first wavelength conversion layer; The method for manufacturing a wavelength conversion member according to claim 17 , further comprising a step of bonding the second intermediate layer and the second translucent member.

19. 20. The method for manufacturing a wavelength conversion member according to claim 18, wherein in the step of bonding the second intermediate layer and the second translucent member, the second intermediate layer and the second translucent member are bonded via a first adhesive layer.

20. 20. The method for manufacturing a wavelength conversion member according to claim 19, comprising: a step of forming a second adhesive layer having a thickness greater than that of the first wavelength conversion layer around the first wavelength conversion layer on a surface of the first intermediate layer; and a step of bonding a second translucent member to the second adhesive layer.

21. forming a first intermediate layer on a surface of a first light-transmissive member containing a resin; The first intermediate layer has a perovskite structure on its surface and a composition of ABX ３ forming a first wavelength conversion layer comprising a first phosphor, forming a second intermediate layer on a surface of the first wavelength conversion layer; forming a second wavelength conversion layer on a surface of the second intermediate layer, the second wavelength conversion layer including a second phosphor having an emission peak wavelength in a wavelength range different from that of the first phosphor; The first phosphor is ＋ , C.H. ３ N.H. ３ ＋ , and Cs ＋ and B is at least one cation selected from the group consisting of Pb ２＋ , and Sn ２＋ and X is at least one metal ion selected from the group consisting of F － , Cl － , B － , and I － The method for producing a wavelength conversion member, wherein the anion is at least one type of anion selected from the group consisting of:

22. forming a third intermediate layer on a surface of the second wavelength conversion layer; The method for manufacturing a wavelength conversion member according to claim 21 , comprising a step of bonding the third intermediate layer and the second translucent member.

23. The method for manufacturing a wavelength conversion member according to claim 22 , wherein in the step of bonding the third intermediate layer and the second light-transmissive member, the third intermediate layer and the second light-transmissive member are bonded via a third adhesive layer.

24. 22. The method for manufacturing a wavelength conversion member according to claim 21, comprising: a step of forming a fourth adhesive layer having a thickness greater than that of the second wavelength conversion layer around the second wavelength conversion layer on a surface of the second intermediate layer; and a step of adhering a second translucent member to the fourth adhesive layer.

25. 25. The method for producing a wavelength conversion member according to claim 17, wherein the first phosphor is a cesium lead halide, and the first wavelength conversion layer is formed by using a vapor deposition method.

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