Phosphor composite particles, wavelength conversion member, light-emitting device, method for manufacturing phosphor composite particles, and method for manufacturing wavelength conversion member

Abstract

To provide a fluorescent composite particle that can maintain the luminescent property of fluorescent nanoparticles.SOLUTION: A fluorescent composite particle 1 includes light-transmitting inorganic particles 2 having a volume average particle size within a range of 30 nm or more and 500 nm or less, fluorescent nanoparticles 3 having an average particle size within a range of 5 nm or more and 25 nm or less, and a first resin 4, in which at least parts of the light-transmitting inorganic particles 2 are embedded in the first resin 4 and unevenly distributed on the particle surface, and has a volume average particle size within a range of 0.5 μm or more and 50 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to phosphor composite particles, wavelength conversion members, light-emitting devices, methods for manufacturing phosphor composite particles, and methods for manufacturing wavelength conversion members. [Background technology]

[0002] Light emission from quantum dots (QDs), which are semiconductor nanoparticles, exhibits excellent color purity. Furthermore, quantum dots are used as fluorescent materials in wavelength conversion films for displays, due to their superior quantum efficiency and excellent color reproduction. Display devices are increasingly demanding higher image quality. Therefore, wavelength conversion components and color filters are required to support wider color gamuts, as specified in the BT2020 standard. Fluorescent nanoparticles are promising as phosphors for use in wavelength conversion components because they have a narrower full width at half maximum of the emission spectrum with the emission peak wavelength, superior color purity, and high quantum efficiency compared to conventional quantum dots.

[0003] Fluorescent nanoparticles are easily decomposed by moisture, and their luminescence properties tend to deteriorate. When a wavelength conversion member is formed by incorporating fluorescent nanoparticles into a resin material, it is difficult to suppress the deterioration of the luminescence properties of the fluorescent nanoparticles because moisture easily diffuses and penetrates the resin material. For this reason, wavelength conversion members are sometimes used in which both sides of the resin layer containing fluorescent nanoparticles are laminated with a resin film that has a barrier layer to protect the resin layer from moisture and air. However, even when the resin layer containing fluorescent nanoparticles is laminated with a resin film that has a barrier layer, it is not sufficient to protect the fluorescent nanoparticles from moisture and air.

[0004] For example, Patent Document 1 discloses quantum dot beads in which the surface of polymer beads such as acrylate, which contain quantum dots, is coated with a layer of metal oxide by atomic deposition (ALD) method. Patent Document 2 also discloses phosphor-containing particles in which granular resin containing semiconductor nanoparticle phosphors and a metal oxide are dispersed in a dispersion medium, and the metal oxide is deposited on the surface of the granular material by evaporating the dispersion medium. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Special Publication No. 2016-518468 [Patent Document 2] Japanese Patent Publication No. 2018-203965 [Overview of the project] [Problems that the invention aims to solve]

[0006] Particles containing fluorescent nanoparticles require further improvement to maintain their luminescence properties.

[0007] One aspect of the present invention aims to provide phosphor composite particles, a wavelength conversion member, a light-emitting device, a method for producing phosphor composite particles, and a method for producing a wavelength conversion member, all of which can maintain high luminescence characteristics of fluorescent nanoparticles. [Means for solving the problem]

[0008] The first embodiment is a phosphor composite particle comprising translucent inorganic particles having a volume average particle size in the range of 30 nm to 500 nm, fluorescent nanoparticles having an average particle size in the range of 5 nm to 25 nm, and a first resin, wherein at least a portion of the translucent inorganic particles are embedded in the first resin and unevenly distributed on the particle surface, and the volume average particle size is in the range of 0.5 μm to 50 μm.

[0009] The second embodiment is a phosphor composite particle comprising translucent inorganic particles having a volume average particle size in the range of 30 nm to 500 nm, fluorescent nanoparticles having an average particle size in the range of 5 nm to 25 nm, and a first resin, wherein at least a portion of the translucent inorganic particles are embedded in the first resin and unevenly distributed on the particle surface, and at least a portion of the surface of the translucent inorganic particles is provided with a film-like material containing an inorganic substance that transmits light with a wavelength of 400 nm or more, and the volume average particle size is in the range of 0.5 μm to 50 μm.

[0010] A third embodiment is a wavelength conversion member comprising the phosphor composite particles and a second resin.

[0011] A fourth embodiment is a light-emitting device comprising the phosphor composite particles and an excitation light source.

[0012] The fifth embodiment is a light-emitting device including the wavelength conversion member and an excitation light source.

[0013] The sixth aspect is a method for producing phosphor composite particles, comprising: preparing a first dispersion that will be a dispersed phase, comprising fluorescent nanoparticles, a radical polymerizable monomer, and a polymerization initiator; preparing a second dispersion that will be a continuous phase, comprising a suspension stabilizer containing translucent inorganic particles and an organic solvent; and mixing the first dispersion and the second dispersion and performing suspension polymerization, wherein when particles of a first resin containing the fluorescent nanoparticles are formed by polymerization of the radical polymerizable monomer, at least a portion of the translucent inorganic particles are embedded in the first resin and unevenly distributed on the particle surface by a Pickering emulsion in which the translucent inorganic particles are present at the oil / oil interface.

[0014] The seventh aspect is a method for manufacturing a wavelength conversion member, which includes forming a wavelength conversion sheet on the surface of a light-transmitting member using a wavelength conversion sheet composition comprising the phosphor composite particles and a second resin.

[0015] The eighth aspect is a method for manufacturing a wavelength conversion member, which includes arranging a wavelength conversion sheet composition containing the phosphor composite particles and a second resin on the surface of a first light-transmitting member, arranging a second light-transmitting member with the wavelength conversion sheet composition sandwiched between it and the first light-transmitting member, and joining the first light-transmitting member and the second light-transmitting member with a wavelength conversion sheet sandwiched between them. [Effects of the Invention]

[0016] According to one aspect of the present invention, it is possible to provide phosphor composite particles that can maintain the luminescence properties of fluorescent nanoparticles, a wavelength conversion member, a light-emitting device, a method for producing phosphor composite particles, and a method for producing a wavelength conversion member. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic cross-sectional view showing a first embodiment of phosphor composite particles. [Figure 2] This is a schematic cross-sectional view showing a second embodiment of phosphor composite particles. [Figure 3] This is a flowchart showing a first embodiment of a method for manufacturing phosphor composite particles. [Figure 4] This is a schematic diagram illustrating the state of suspension polymerization. [Figure 5] This is a schematic diagram showing the state in which phosphor composite particles are obtained by suspension polymerization. [Figure 6] This is a flowchart showing a second embodiment of a method for producing phosphor composite particles. [Figure 7] This is a schematic cross-sectional view showing a first embodiment of the wavelength conversion member. [Figure 8] This is a schematic cross-sectional view showing a second embodiment of the wavelength conversion member. [Figure 9] This is a schematic cross-sectional view showing a first example configuration of a light-emitting device. [Figure 10] This is a schematic cross-sectional view showing a second example configuration of the light-emitting device. [Figure 11] This is a schematic perspective view showing a second configuration example of the light-emitting device. [Figure 12] This is a schematic cross-sectional view showing a third configuration example of the light-emitting device. [Figure 13] This is a schematic plan view showing a third configuration example of the light-emitting device. [Figure 14] This is a schematic cross-sectional view showing an edge-lit backlight structure, which is an example of an image display device. [Figure 15] This is a schematic cross-sectional view relating to another example of an image display device, showing a direct-lit backlight structure. [Figure 16]These are the XRD patterns of a fluorescent nanoparticle precursor having a composition represented by FAPbBr3 and the XRD pattern of FAPbBr3 registered in ICSD. [Figure 17] This is a TEM image of fluorescent nanoparticles in solution. [Figure 18] This is an SEM image (backscattered electron image) of the phosphor composite particles according to Example 1. [Figure 19] This is a magnified view of a portion of the SEM image (backscattered electron image) of the phosphor composite particles according to Example 1. [Figure 20] This is an SEM image (backscattered electron image) of a cross-section of the phosphor composite particles according to Example 1. [Figure 21] This is a partially enlarged view of a SEM image (backscattered electron image) of a cross-section of the phosphor composite particles according to Example 1. [Figure 22] This graph shows the relationship between time and the emission intensity maintenance rate (%) for the wavelength conversion members according to Examples 1 to 3 and the wavelength conversion member according to Comparative Example 1. [Figure 23] This is a schematic cross-sectional view of phosphor-containing particles disclosed in prior art documents. [Figure 24] This is a schematic cross-sectional view of a quantum dot bead disclosed in prior art literature. [Modes for carrying out the invention]

[0018] The following describes the phosphor composite particles, wavelength conversion member, light-emitting device, method for manufacturing phosphor composite particles, and method for manufacturing wavelength conversion member according to the present invention, based on embodiments. However, the embodiments shown below are illustrative examples for realizing the technical concept of the present invention, and the present invention is not limited to the following phosphor composite particles, wavelength conversion member, light-emitting device, method for manufacturing phosphor composite particles, and method for manufacturing wavelength conversion member. The relationship between color names and chromaticity coordinates, and the relationship between the wavelength range of light and the color names of monochromatic light, conform to JIS Z8110. In this specification, terms such as "sheet," "film," and "layer" are not distinguished from each other solely on the basis of differences in designation. Therefore, for example, "film" is used to include members that may also be called sheets, and "sheet" is used to include members that may also be called films.

[0019] The phosphor composite particles according to the first embodiment include translucent inorganic particles with a volume average particle size in the range of 30 nm to 500 nm, fluorescent nanoparticles with an average particle size in the range of 5 nm to 25 nm, and a first resin, wherein at least a portion of the translucent inorganic particles are embedded in the first resin and unevenly distributed on the particle surface, and the volume average particle size is in the range of 0.5 μm to 50 μm.

[0020] The schematic structure of the phosphor composite particles will be described with reference to the drawings. Figure 1 is a schematic cross-sectional view showing a first embodiment of the phosphor composite particles. The phosphor composite particle 1 includes translucent inorganic particles 2, fluorescent nanoparticles 3, and a first resin 4. In the phosphor composite particle 1, the fluorescent nanoparticles 3 are contained within the particles of the first resin 4, and at least a portion of the translucent inorganic particles 2 are embedded in the first resin 4 and unevenly distributed on the particle surface.

[0021] In the phosphor composite particle 1, translucent inorganic particles 2 are present on the surface of the particles of the first resin 4 containing fluorescent nanoparticles 3 with almost no gaps. The translucent inorganic particles 2 are unevenly distributed on the surface of the particles, with at least a portion embedded in the first resin 4. Because the translucent inorganic particles 2 are unevenly distributed in the phosphor composite particle 1, with at least a portion embedded on the surface of the particles of the first resin 4 containing fluorescent nanoparticles 3 with almost no gaps, moisture and other substances are less likely to penetrate into the first resin 4, and the fluorescent nanoparticles 3 contained in the first resin 4 are protected. The fluorescent nanoparticles 3 have a tetragonal or cubic crystal structure, and their crystal structure is easily decomposed by moisture. If the crystal structure is decomposed by moisture, the luminescence properties of the fluorescent nanoparticles 3 cannot be maintained. When translucent inorganic particles 2 are present on the surface of the first resin 4 with at least a portion embedded with almost no gaps, the effect of suppressing the penetration of moisture into the first resin 4 is greatly increased, and the phosphor composite particle 1 can maintain the luminescence properties of the fluorescent nanoparticles 3.

[0022] Figure 23 is a schematic cross-sectional view showing the schematic structure of the phosphor-containing particles C1 disclosed in the aforementioned Patent Document 2. The phosphor-containing particles C1 disclosed in Patent Document 2 are formed by dispersing granular resin C4 containing constituent units derived from an ionic liquid having polymerizable functional groups in which semiconductor nanoparticles C3 are dispersed, and metal oxide C2 in a dispersion medium, and evaporating the dispersion medium at a temperature of 30°C to 150°C to deposit the metal oxide C2 onto the surface of the granular resin C4, thereby forming a layer of metal oxide. In the phosphor-containing particles C1 disclosed in Patent Document 2, since the granular resin C4 contains semiconductor nanoparticles C3 and metal oxide C2 particles are deposited onto the surface of the granular resin C4 by drying the dispersion medium, a gap C5 is formed between the surface of the granular resin C4 and the metal oxide C2. When a gap exists between the granular resin C4 and the metal oxide C2, moisture can easily penetrate through this gap, and the semiconductor nanoparticles C3 in the resin C4 may be decomposed by the moisture, which may reduce the luminescence properties of the semiconductor nanoparticles.

[0023] Figure 24 is a schematic cross-sectional view showing the schematic configuration of the quantum dot beads D1 disclosed in the aforementioned Patent Document 1. In the quantum dot beads D1 disclosed in Patent Document 1, a first surface coating layer D2a and a second surface coating layer D2b are alternately stacked on the surface of primary particles of a primary matrix material D4, such as a resin, in which quantum dot nanoparticles D3 are dispersed. The first surface coating layer D2a is formed by atomic deposition (ALD) using an inorganic material such as a metal oxide, and the second surface coating layer D2b is formed by ALD using an alkoxide alloy polymer, for example. It is presumed that if a surface coating layer is formed on the surface of primary particles containing quantum dot nanoparticles D3 and the primary matrix material D4 by ALD or the like, the penetration of moisture will be suppressed. However, the thermal expansion coefficients of the resin, which is the primary matrix material D4 constituting the primary particles, and the metal oxide, which is constituting the surface coating layer D2a, for example, have very different coefficients. When the quantum dot beads D1 are repeatedly heated and cooled by the presence or absence of light irradiation from an excitation light source, the difference in thermal expansion coefficients makes the first surface coating layer D2a or the second surface coating layer D2b more susceptible to peeling or cracking.

[0024] In contrast, in the phosphor composite particle 1 according to this embodiment, translucent inorganic particles 2 exist on the surface of the particles of the first resin 4 containing fluorescent nanoparticles 3, with at least a portion embedded in the first resin 4. Even when the phosphor composite particle 1 is repeatedly heated and cooled by the presence or absence of irradiation with light from an excitation light source, the translucent inorganic particles 2, which exist with at least a portion embedded on the surface of the particles of the first resin 4, can widen or narrow the space between adjacent translucent inorganic particles 2 in accordance with the expansion and contraction of the first resin 4. Even if the thermal expansion coefficient of the translucent inorganic particles 2 and the thermal expansion coefficient of the first resin 4 are different, the phosphor composite particle 1 can widen or narrow the space between adjacent translucent inorganic particles 2 in accordance with the expansion and contraction of the first resin 4. As a result, peeling of the translucent inorganic particles 2 is less likely to occur, the penetration of moisture into the first resin 4 can be suppressed, and the high luminescence characteristics of the fluorescent nanoparticles 3 contained in the first resin 4 can be maintained.

[0025] The phosphor composite particle 1 according to the second embodiment comprises translucent inorganic particles having a volume average particle size in the range of 30 nm to 500 nm, fluorescent nanoparticles having an average particle size in the range of 5 nm to 25 nm, and a first resin. At least a portion of the translucent inorganic particles are embedded in the first resin and unevenly distributed on the particle surface, and at least a portion of the surface of the translucent inorganic particles is provided with a film-like material containing an inorganic substance that transmits light with a wavelength of 400 nm or more, and the volume average particle size is in the range of 0.5 μm to 50 μm.

[0026] Figure 2 is a schematic cross-sectional view showing a second embodiment of the phosphor composite particle. The phosphor composite particle 1 comprises translucent inorganic particles 2, fluorescent nanoparticles 3, a first resin 4, and a film-like material 5. The phosphor composite particle 1 includes fluorescent nanoparticles 3 in the particles of the first resin 4, at least a portion of the translucent inorganic particles 2 are embedded in the first resin 4 and unevenly distributed on the particle surface, and a film-like material 5 containing an inorganic substance that transmits light with a wavelength of 400 nm or more on at least a portion of the surface of the translucent inorganic particles 2.

[0027] In the phosphor composite particle 1, translucent inorganic particles 2 are unevenly distributed with at least a portion embedded on the surface of particles of the first resin 4 containing fluorescent nanoparticles 3, and a film-like substance 5 is provided on at least a portion of the surface of the translucent inorganic particles 2. As a result, the penetration of moisture into the first resin 4 is further suppressed, and the fluorescent nanoparticles 3 contained in the first resin 4 are better protected from moisture.

[0028] Translucent inorganic particles The translucent inorganic particles have a volume-average particle size in the range of 30 nm to 500 nm. In this specification, the volume-average particle size refers to the average particle size (median diameter) of the cumulative 50% in the volume-based particle size distribution measured by laser diffraction (also called "laser diffraction scattering method"). The volume-average particle size can be measured, for example, using a laser diffraction particle size distribution analyzer (e.g., MATER SIZER2000, manufactured by MALVERN). The volume-average particle size of the translucent inorganic particles may be the value listed in catalogs, etc., as long as it is the volume-average particle size measured by laser diffraction. The volume-average particle size of the translucent inorganic particles may be in the range of 50 nm to 400 nm, in the range of 80 nm to 300 nm, or in the range of 100 nm to 250 nm. If the volume-average particle size of the translucent inorganic particles is in the range of 30 nm to 500 nm, at least a portion of the translucent inorganic particles can be embedded in the surface of the first resin and unevenly distributed on the particle surface.

[0029] The translucent inorganic particles are preferably at least one oxide or fluoride selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride. The translucent inorganic particles are preferably low in refractive index in order to facilitate the transmission of excitation light and the emission of fluorescent nanoparticles. The translucent inorganic particles are preferably 4.0 or less, more preferably 3.5 or less, even more preferably 3.0 or less, and particularly preferably 2.5 or less. The refractive index of silicon dioxide is 1.46, the refractive index of aluminum oxide is 1.77, the refractive index of zirconium oxide is 2.21, the refractive index of titanium oxide is 2.49, and the refractive index of magnesium fluoride is 1.38.

[0030] Fluorescent nanoparticles Fluorescent nanoparticles have an average particle size in the range of 5 nm to 25 nm. The average particle size of fluorescent nanoparticles may also be in the range of 6 nm to 22 nm, or 8 nm to 20 nm. The average particle size of fluorescent nanoparticles can be determined from the TEM image of the fluorescent nanoparticles obtained using a transmission electron microscope (TEM). Specifically, the particle size of a fluorescent nanoparticle refers to the longest line segment that passes through the center of the particle, connecting any two points on its outer circumference as observed in the TEM image. The average particle size of fluorescent nanoparticles is the arithmetic mean of the particle sizes of measurable fluorescent nanoparticles observed in the TEM image.

[0031] When the fluorescent nanoparticles have a rod-shaped particle, the length of the short axis is regarded as the particle diameter. Here, the rod-shaped particle refers to a quadrangular shape including a rectangular shape (the cross section has a circle, an ellipse, or a polygonal shape), an elliptical shape, or a polygonal shape (such as the shape of a pencil), etc., and the ratio of the length of the long axis to the length of the short axis is greater than 1.2. For the rod-shaped particle, the length of the long axis refers to the longest one among the line segments connecting any two points on the outer periphery of the particle in the case of an elliptical shape, and in the case of a rectangular shape or a polygonal shape, it is parallel to the longest side among the sides defining the outer periphery and refers to the longest one among the line segments connecting any two points on the outer periphery of the particle. The length of the short axis refers to the longest line segment that is orthogonal to the line segment defining the length of the long axis among the line segments connecting any two points on the outer periphery. Specifically, the average particle diameter of the fluorescent nanoparticles is the arithmetic mean of the particle diameters measured for all measurable nanoparticles observed in a TEM image at 50,000 to 150,000 times magnification. Here, "measurable" particles are those for which the entire particle can be observed in the TEM image. Therefore, in the TEM image, particles that are "broken" with a part not included in the imaging range are not measurable. When the total number of nanoparticles included in one TEM image is 100 or more, the average particle diameter is determined using one TEM image. When the number of nanoparticles included in one TEM image is small, the imaging location is changed to obtain more TEM images, and the particle diameters are measured for 100 or more particles included in two or more TEM images.

[0032] The fluorescent nanoparticles preferably contain a compound having a composition represented by the following formula (1). [M 1 d A 1 e a M 2 b X c (1) In the formula (1), M 1 is at least one first element selected from the group consisting of Cs, Rb, K, Na, and Li, and A 1 ​M is at least one organic cation selected from the group consisting of ammonium ions, formamidinium ions, guanidinium ions, imidazolium ions, pyridinium ions, pyrrolidinium ions, and protonated thiourea ions. 2 M is at least one second element selected from the group consisting of Ge, Sn, Pb, Sb, and Bi, X is an anion or ligand selected from the group consisting of chloride, bromide, iodine, cyanide, thiocyanate, isothiocyanate, and sulfide, a is an integer from 1 to 4, b is an integer from 1 to 2, c is an integer from 3 to 9, d is from 0 to 1, e is from 0 to 1, and d+e=1. In formula (1) above, the first element M 1 and organic cation A 1 If both are included, the first element M 1 and organic cation A 1 Both represent the atomic groups that make up the ligand.

[0033] Ammonium ions are [R4N + It is represented as ](A-1), and the formamidinium ion is [(NR2)2RC + It is represented as ](A-2), and the guanidinium ion is [(NR2)3C + It is represented as ](A-3), and the protonated thiourea ion is [(NR2)SHR2N + It is represented by (A-4). The imidazolium ion is represented by the following formula (A-5), the pyridinium ion by the following formula (A-6), and the pyrrolidinium ion by the following formula (A-7). In the formulas representing organic cations, R independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a benzyl group, a halogen atom, or a pseudohalogen.

[0034] [ka]

[0035] Fluorescent nanoparticles containing a compound having the composition represented by formula (1) emit light in response to light from an excitation light source. Preferably, the fluorescent nanoparticles are excited by light from an excitation light source having an emission peak wavelength in the range of 380 nm to 500 nm, and emit light having an emission peak wavelength in the range of greater than 500 nm and less than or equal to 600 nm. Alternatively, the fluorescent nanoparticles may be excited by light having an emission peak wavelength in the range of 380 nm to 500 nm, and emit light having an emission peak wavelength in the range of 510 nm to 570 nm, or light having an emission peak wavelength in the range of 520 nm to 560 nm.

[0036] Fluorescent nanoparticles containing a compound having the composition represented by formula (1) have high light absorption capacity, high emission intensity, and vivid emission color. The compound having the composition represented by formula (1) has a cubic perovskite crystal structure. Fluorescent nanoparticles containing a compound having the composition represented by formula (1) have a narrow full width at half maximum in the emission spectrum showing maximum emission intensity, good color purity, and can improve color reproducibility when mixed with light from other wavelength regions. In this specification, full width at half maximum refers to the full width at half maximum of the emission spectrum, and in the emission spectrum, it refers to the wavelength range where the emission intensity is 50% of the emission intensity at the emission peak wavelength showing maximum emission intensity. Fluorescent nanoparticles having the composition represented by formula (1) preferably have a narrow full width at half maximum in the emission spectrum, preferably 35 nm or less, more preferably 30 nm or less, and even more preferably 25 nm or less.

[0037] The cubic perovskite crystal structure ideally has a cubic unit cell, with the first element M constituting each vertex of the cubic crystal. 1 and / or organic cation A 1 The first chemical species consists of and the second element M which constitutes the body center of the cubic crystal. 2 It has, and this second element M 2A second chemical species X, consisting of an anion or ligand, forms an octahedron centered around a central element. Preferably, the second chemical species X constituting the octahedron is arranged at the center of each face of the cubic crystal. The second chemical species X and the second element M 2 The octahedron, composed of the first element M, is 1 and / or organic cation A 1 Due to interactions with the first chemical species, the material is easily distorted, and there are also voids in the crystal structure where the first and second chemical species are absent. Fluorescent nanoparticles containing compounds with a perovskite-type crystal structure are easily decomposed by moisture due to the distortion and voids in the perovskite-type crystal structure of the compound. Fluorescent nanoparticles contained in phosphor composite particles are protected from moisture-induced decomposition by the first resin and the translucent inorganic particles partially embedded on the surface of the first resin particles, thus maintaining high luminescence properties.

[0038] Fluorescent nanoparticles preferably contain compounds with a chalcopyrite-type crystal structure. Examples of compounds containing a chalcopyrite-type crystal structure include those represented by the compositional formula of AgInS2 having a tetragonal crystal structure. Specifically, as fluorescent nanoparticles, compounds containing a chalcopyrite-type crystal structure can be found in, for example, the compounds disclosed in Japanese Patent No. 6464215 and Japanese Patent Application Publication No. 2019-085575.

[0039] Fluorescent nanoparticles containing compounds with a chalcopyrite-type crystal structure emit light when stimulated by light from an excitation light source. Preferably, the fluorescent nanoparticles are excited by light from an excitation light source with an emission peak wavelength in the range of 380 nm to 500 nm, and emit light with an emission peak wavelength greater than 510 nm and less than or equal to 580 nm. Alternatively, the fluorescent nanoparticles may be excited by light with an emission peak wavelength in the range of 380 nm to 500 nm and emit light with an emission peak wavelength in the range of 510 nm to 550 nm, or light with an emission peak wavelength in the range of 515 nm to 545 nm. Fluorescent nanoparticles containing compounds with a chalcopyrite-type crystal structure have a full width at half maximum (FWHM) of 45 nm or less in their emission spectrum, but may also be 40 nm or less, or 35 nm or less. When light with a relatively broad FWHM emission spectrum is emitted, the appearance of the color of an object when irradiated with light (hereinafter also referred to as "color rendering") is excellent.

[0040] First resin The first resin preferably contains a polymer obtained by polymerizing radically polymerizable monomers. When the first resin is a polymer obtained by polymerizing radically polymerizable monomers, the first resin can contain fluorescent nanoparticles, and phosphorescent composite particles can be obtained in which translucent inorganic particles are unevenly distributed, with at least a portion of them embedded on the surface of the particles of the first resin.

[0041] The radical polymerizable monomer is preferably at least one monomer selected from the group consisting of acrylates, methacrylates, styrene, butadiene, isoprene, maleic anhydride, maleic acid derivatives, and fumaric acid derivatives.

[0042] Membrane The phosphor composite particles according to the second embodiment may have a film-like material on at least a portion of the surface of the translucent inorganic particles, which are embedded in the surface of the first resin and unevenly distributed on the particle surface, containing an inorganic substance that transmits light with a wavelength of 400 nm or more. When the phosphor composite particles have a film-like material, the intrusion of moisture from the outside can be further suppressed, the crystalline structure of the fluorescent nanoparticles contained in the first resin can be maintained, and the luminescence characteristics of the fluorescent nanoparticles can be maintained. The film-like material may transmit light with a wavelength of 850 nm or less.

[0043] The film-like substance is preferably at least one inorganic substance selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride. The inorganic substance contained in the film-like substance may be the same type as the translucent inorganic particles, or it may be a different type.

[0044] The thickness of the film is preferably in the range of 10 nm to 500 nm, but may also be in the range of 20 nm to 300 nm, or in the range of 50 nm to 200 nm. If the thickness of the film is in the range of 10 nm to 500 nm, it is possible to suppress the penetration of moisture from the outside into the first resin without suppressing the transmission of excitation light and the emission of fluorescent nanoparticles, and to maintain the crystal structure of the fluorescent nanoparticles and maintain the high luminescence efficiency of the fluorescent nanoparticles. The thickness of the film-like material attached to the phosphor composite particles can be measured as follows: The phosphor composite particles are embedded in a resin, and after the resin hardens, the cross-section of the phosphor composite particles is cut to expose it. Next, the cut cross-section is polished and cut out using a focused ion beam (FIB) device. The cut-out portion is then observed using a scanning electron microscope (SEM). The thickness of the film-like material can be measured from the SEM image obtained using the SEM. Epoxy resin can be used as the resin in which the phosphor composite particles are embedded.

[0045] The volume-average particle size of the phosphor composite particles is within the range of 0.5 μm to 50 μm. The volume-average particle size of the phosphor composite particles refers to the average particle size (median diameter) of the cumulative 50% of the volume-based particle size distribution measured by laser diffraction particle size distribution analysis. The volume-average particle size of the phosphor composite particles may also be within the range of 1.0 μm to 40 μm, 2.0 μm to 35 μm, or 3.0 μm to 30 μm. If the volume-average particle size of the phosphor composite particles is within the range of 0.5 μm to 50 μm, it is easy to handle and allows for an appropriate amount of fluorescent nanoparticles to be included in the first resin of the phosphor composite particles. The volume-average particle size of the phosphor composite particles is within the range of 0.5 μm to 50 μm even when a film-like material is present on at least a part of the surface of the translucent inorganic particles.

[0046] Method for manufacturing phosphor composite particles A method for producing phosphor composite particles involves preparing a first dispersion, which will be a dispersed phase, containing fluorescent nanoparticles, a radical polymerizable monomer, and a polymerization initiator; preparing a second dispersion, which will be a continuous phase, containing a suspension stabilizer containing translucent inorganic particles and an organic solvent; and mixing the first dispersion and the second dispersion and performing suspension polymerization. In this method, when particles of a first resin containing fluorescent nanoparticles are formed by the polymerization of the radical polymerizable monomer, at least a portion of the translucent inorganic particles are embedded in the first resin and unevenly distributed on the particle surface by a Pickering emulsion in which translucent inorganic particles are present at the oil / oil interface.

[0047] Figure 3 is a flowchart showing a first embodiment of a method for producing phosphor composite particles. The method for producing phosphor composite particles includes a step S101 of preparing a first dispersion liquid which will be a dispersed phase containing fluorescent nanoparticles, a radical polymerizable monomer, and a polymerization initiator; a step S102 of preparing a second dispersion liquid which will be a continuous phase containing a suspension stabilizer containing translucent inorganic particles and an organic solvent; and a step S103 of mixing the first dispersion liquid and the second dispersion liquid and performing suspension polymerization.

[0048] Steps to prepare the first dispersion, which will be the dispersed phase. The first dispersion, which forms the dispersed phase, contains fluorescent nanoparticles, a radical polymerizable monomer, and a polymerization initiator. The fluorescent nanoparticles may be those with an average particle size within the range of 5 nm to 25 nm. Preferably, the fluorescent nanoparticles contain the compound represented by formula (1).

[0049] The radical polymerizable monomer can be one of the radical polymerizable monomers that make up the first resin described above. Preferably, the radical polymerizable monomer is at least one monomer selected from the group consisting of acrylate, methacrylate, styrene, butadiene, isoprene, maleic anhydride, maleic acid derivatives, and fumaric acid derivatives. The radical polymerizable monomer may be used alone or in combination of two or more monomers.

[0050] A polymerization initiator can be any agent that initiates a radical polymerization reaction. The polymerization initiator may be a photopolymerization initiator that initiates the polymerization reaction by irradiation with light, or a thermal polymerization initiator that initiates the polymerization reaction by heat. Examples of photopolymerization initiators include alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, oxime ester-based photopolymerization initiators, and cationic photopolymerization initiators. Examples of alkylphenone-based photopolymerization initiators include 2-hydroxy-2-methyl-1-phenylpropanone and 1-hydroxycyclohexyl-phenyl ketone. Commercially available examples include Omnirad® 1173 and Omnirad® 184 (manufactured by IGM Resins). Examples of acylphosphine oxide-based photopolymerization initiators include diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO). Commercially available products include Omnirad® TPO (manufactured by IGM Resins) and BAPO (manufactured by Tokyo Chemical Industry Co., Ltd.). Oxime ester-based photopolymerization initiators include 1-[4-(phenylthio)phenyl]octane-1,2-dione=2-(O-benzoyloxime). A commercially available product is Irgacure® OXE01 (BASF Japan Ltd.). Cationic photopolymerization initiators include a mixture of iodonium,(4-methylphenyl)]4-(2-methylpropyl)phenyl]-hexafluorophosphate (1-) and propylene carbonate. A commercially available product is Omnicat® 250 (manufactured by IGM Resins). Thermal polymerization initiators include azo-based thermal polymerization initiators or organic peroxide-based thermal polymerization initiators. Examples of azo-based thermal polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN) and 2,2'-azobis(2,4-dimethylvaleronitrile) (ADVN). Examples of organic peroxide-based thermal polymerization initiators include dilauroyl peroxide and t-hexyl peroxypivalate.

[0051] Preferably, the first dispersion, which forms the dispersed phase, contains fluorescent nanoparticles in a range of 0.5% to 10.0% by mass, radical polymerizable monomers in a range of 90% to 99.5% by mass, and polymerization initiators in a range of 0.5% to 2.0% by mass, relative to the total volume of the first dispersion. When the amounts of each component constituting the first dispersion are within the above ranges, when mixed with the second dispersion, which forms the continuous phase (described later), and polymerized by a polymerization reaction, particles of the first resin containing fluorescent nanoparticles are formed, a Pickering emulsion with translucent inorganic particles present at the oil / oil interface allows translucent inorganic particles to be present at the interface between the first resin and the continuous phase. Furthermore, when the amounts of each component constituting the first dispersion, which forms the dispersed phase, are within the above ranges, phosphorescent composite particles with a volume average particle size in the range of 0.5 μm to 50 μm can be obtained. The first dispersion may contain a dispersion medium in which fluorescent nanoparticles are dispersed. For example, toluene can be used as a dispersion medium in which fluorescent nanoparticles are dispersed. The first dispersion, which forms the dispersed phase, is preferably stirred at 100 rpm to 500 rpm for 1 to 5 hours before being mixed with the continuous phase. The stirring time for the first dispersion may be 2 to 4 hours.

[0052] Steps to prepare a second dispersion that will be the continuous phase. The second dispersion, which forms the continuous phase, contains a suspension stabilizer containing translucent inorganic particles and an organic solvent. The translucent inorganic particles can be translucent inorganic particles having a volume-average particle size within the range of 30 nm to 500 nm. Alternatively, the translucent inorganic particles can be at least one oxide or fluoride selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride.

[0053] The suspension stabilizer may contain a surfactant in addition to the translucent inorganic particles. Examples of surfactants include fluorine-based surfactants and silicone-based surfactants. Specific examples of fluorine-based surfactants include 008-Fluorosurfactant (manufactured by RAN Biotechnologies) and FluoSurf (manufactured by Emulseo). Specific examples of silicone-based surfactants include PEG-9 polydimethylsiloxyethyl dimethicone (KF-6028, manufactured by Shin-Etsu Chemical Co., Ltd.) and lauryl PEG-9 polydimethylsiloxyethyl dimethicone (KF-6038, manufactured by Shin-Etsu Chemical Co., Ltd.). By including a surfactant as a suspension stabilizer in the second dispersion liquid, which forms the continuous phase, the interfacial tension of the oil / oil interface between the continuous phase and the dispersed phase is adjusted, allowing translucent inorganic particles to be present at the interface between the first resin, formed by the polymerization of radical polymerizable monomers contained in the dispersed phase, and the continuous phase.

[0054] The organic solvent can be at least one selected from the group consisting of dimethyl silicone oil, methylphenyl silicone oil, organically modified silicone oil, hydrofluoroether, and fluorinated hydrocarbon. As the organically modified silicone oil, at least one organically modified silicone oil can be selected from the group consisting of polyether-modified silicone oil, amino-modified silicone oil, fluoroalkyl-modified silicone oil, and mercapto-modified silicone oil. As the fluorinated hydrocarbon, for example, hydrofluoroether or perfluoroalkane such as perfluorohexane can be used. As a commercially available fluorinated hydrocarbon, Novec® 7500 (manufactured by 3M) can be used as a hydrofluoroether. Also, as perfluoroalkane, Fluorinert® FC-40, Fluorinert® FC-72, and Fluorinert® FC-75 (all manufactured by 3M) can be used. By using an organic solvent in the second dispersion which forms the continuous phase, the inclusion of water can be suppressed, and the decomposition of fluorescent nanoparticles by water during suspension polymerization can be suppressed, thereby maintaining the luminescence properties of the fluorescent nanoparticles and enabling the production of phosphor composite particles.

[0055] The second dispersion, which forms the continuous phase, preferably contains translucent inorganic particles in an amount of 0.5 parts by mass to 10.0 parts by mass per 100 parts by mass of the first dispersion, which forms the dispersed phase. It may also be in the range of 1.0 parts by mass to 8.0 parts by mass, or 2.0 parts by mass to 6.0 parts by mass. When the second dispersion contains translucent inorganic particles in an amount of 0.5 parts by mass to 10.0 parts by mass per 100 parts by mass of the first dispersion, the interfacial tension between the continuous phase and the dispersed phase can be adjusted during suspension polymerization, and when the particles of the first resin are formed, translucent inorganic particles can be present at the oil / oil interface between the droplets of the radical polymerizable monomer that will become the first resin and the continuous phase by a Pickering emulsion. The second dispersion is preferably stirred at 100 rpm to 5000 rpm for 3 minutes to 2 hours. The stirring time for the second dispersion may be 5 minutes to 1 hour.

[0056] Suspension polymerization process The first dispersion and the second dispersion are mixed to form a suspension in which the first dispersion, containing fluorescent nanoparticles, radical polymerizable monomers, and polymerization initiators, becomes the dispersed phase, and the second dispersion, containing translucent inorganic particles and an organic solvent, becomes the continuous phase. Figure 4 is a schematic diagram showing the state of suspension polymerization. The continuous phase Cp contains translucent inorganic particles Cp2. The dispersed phase Dp contains radical polymerizable monomers Dp4 and fluorescent nanoparticles Dp3.

[0057] When light or heat is applied to a suspension containing a dispersed phase Dp and a continuous phase Cp in a container, the polymerization initiator in the dispersed phase Dp initiates the polymerization reaction of the radical polymerizable monomer Dp4, forming particles of a first resin containing fluorescent nanoparticles. During the formation of the first resin particles, the translucent inorganic particles Cp2 contained in the continuous phase Cp are adsorbed at the oil / oil interface between the continuous phase Cp and the droplets of the radical polymerizable monomer Dp4 (dispersed phase Dp) by a Pickering emulsion.

[0058] Figure 5 is a schematic diagram showing the state in which phosphor composite particles are obtained by suspension polymerization. At the oil / oil interface between the continuous phase Cp and droplets of the dispersed phase Dp, which is a radical polymerizable monomer Dp4, translucent inorganic particles are adsorbed by a Pickering emulsion, and the polymerization reaction of the radical polymerizable monomer proceeds. As a result, in the first resin 4 formed by the polymerization of the radical polymerizable monomer, the translucent inorganic particles 2 are embedded in the first resin and unevenly distributed on the particle surface, and phosphor composite particles 1 are produced in this state. In the phosphor composite particles 1 obtained by suspension polymerization, at least a portion of the translucent inorganic particles 2, which are embedded in the first resin, are present on the particle surface with almost no gaps.

[0059] A method for producing phosphor composite particles preferably involves attaching a film-like substance containing an inorganic material that transmits light with a wavelength of 400 nm or more to at least a portion of the surface of a translucent inorganic particle.

[0060] Figure 6 is a flowchart showing a second embodiment of a method for producing phosphor composite particles. The method for producing phosphor composite particles includes a step S201 of preparing a first dispersion liquid which will be the dispersed phase, a step S202 of preparing a second dispersion liquid which will be the continuous phase, a step S203 of mixing the first dispersion liquid and the second dispersion liquid and performing suspension polymerization, and a step S204 of attaching a film-like substance.

[0061] It is preferable that, before attaching the film-like substance, the phosphor composite particles are separated from the continuous phase after suspension polymerization and dried. The phosphor composite particles separated from the continuous phase may be washed and dried. Washing and solid-liquid separation may be repeated multiple times. When washing multiple times, different types of washing solutions may be used for the first wash and for the second and subsequent washes. It is preferable to use a non-polar solvent such as toluene or hexane as the washing solution. Polar organic solvents such as chloroform, methanol, ethanol, isopropyl alcohol, acetone, dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF) may also be used as the washing solution. One type of washing solution may be used, or two or more types may be mixed and used. Drying can be performed at a temperature in the range of 15°C to 35°C in an atmospheric environment for one hour or more.

[0062] Process of attaching a film-like substance In a method for producing phosphor composite particles, as one aspect of the step of attaching a film-like substance, the film-like substance can be attached to the surface of the translucent inorganic particles of the phosphor composite particles by a sol-gel method. In another aspect of the method for producing phosphor composite particles, as another aspect of the step of attaching a film-like substance, the film-like substance can be attached to the surface of the translucent inorganic particles of the phosphor composite particles by an atomic layer deposition (ALD) method. Preferably, the film-like substance contains at least one inorganic substance selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride.

[0063] Adhesion of film-like substances by sol-gel method The phosphor composite particles are brought into contact with a solution containing a metal alkoxide containing at least one element selected from the group consisting of Si, Al, Zr, and Ti, and the metal alkoxide is hydrolyzed and polymerized to deposit an oxide containing at least one element selected from the group consisting of Si, Al, Zr, and Ti. According to the sol-gel method, by bringing the phosphor composite particles into contact with a solution containing a metal alkoxide and hydrolyzing and polymerizing the metal alkoxide, at least one oxide selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride is deposited as a main component, preferably in a film-like manner, on the surface of the translucent inorganic particles, thereby obtaining phosphor composite particles with a film-like substance. In this specification, the main component means that the film-like substance contains 50% by volume or more of at least one oxide selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, and titanium oxide. This film-like substance functions as a protective film, and together with translucent inorganic particles that are unevenly distributed with at least a portion embedded on the particle surface of the first resin, it can suppress the intrusion of moisture from the outside and maintain the luminescence efficiency of the fluorescent nanoparticles in the first resin.

[0064] The metal alkoxide is preferably a silane compound having two or more alkoxyl groups. Specifically, examples include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, titanium tetrapropoxide, titanium tetrabutoxide, aluminum triethoxide, aluminum tripropoxide, aluminum tripbutoxide, zirconium tetrapropoxide, and zirconium tetrabutoxide. Considering workability and availability, the metal alkoxide is preferably tetraethoxysilane.

[0065] The solution containing the metal alkoxide preferably contains an organic solvent for ease of use. The organic solvent in the solution containing the metal alkoxide is preferably a polar organic solvent, such as ethyl acetate, tetrahydrofuran, N,N-diethylformamide, dimethyl sulfoxide, alcohols having linear or branched alkyl groups with 1 to 8 carbon atoms, carboxylic acids such as formic acid and acetic acid, and ketones such as acetone. The polar organic solvent may preferably be a lower alcohol or ketone having linear or branched alkyl groups with 1 to 3 carbon atoms. The polar organic solvent may more preferably be ethanol or ketone with a dielectric constant of 18 to 33. Specifically, the polar organic solvent is more preferably at least one selected from the group consisting of methanol (dielectric constant 33), ethanol (dielectric constant 24), 1-propanol (dielectric constant 20), 2-propanol (dielectric constant 18), and acetone (dielectric constant 21). By including an acid or alkali catalyst in the solution containing the metal alkoxide, the hydrolysis decomposition rate of the metal alkoxide can be accelerated. Examples of catalytic acid or alkali solutions include hydrochloric acid solution and ammonia solution.

[0066] Deposition of film-like substances by atomic deposition method By forming a film-like substance on the surface of the translucent inorganic particles of a phosphor composite particle using atomic deposition, a film-like substance of uniform thickness can be formed without gaps on the surface of the phosphor composite particle. This film-like substance functions as a protective film, suppressing the evaporation of moisture contained in the phosphor composite particle and the intrusion of moisture from the outside, thereby maintaining high luminescence efficiency. Formation of the film-like substance by atomic deposition involves, for example, introducing the phosphor composite particle into an atomic layer deposition apparatus, then introducing, for example, trimethylaluminum (TMA) gas into the atomic layer deposition apparatus to react the OH groups on the surface of the translucent inorganic particles on the surface of the phosphor composite particle with the TMA. Next, the excess gas is exhausted. Then, H2O gas is introduced to react the TMA, which was bonded to the OH groups in the previous reaction, with the H2O. Next, the excess gas is exhausted. By repeating the reaction with TMA, exhaust, reaction with OH groups, and exhaust as one cycle, a protective film of a predetermined thickness, for example, Al2O3, can be formed. Alternatively, a protective film can be formed by introducing H2O2 gas or ozone (O3) instead of H2O gas. The film-like material formed by atomic deposition preferably contains at least one inorganic substance selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride.

[0067] The method for producing phosphor composite particles may include forming a film-like substance on the surface of the translucent inorganic particles of the phosphor composite particle, followed by heat treatment at a temperature of 40°C to 120°C. By forming a film-like substance on the surface of the translucent inorganic particles of the phosphor composite particle and then heat-treating it at a temperature of 40°C to 120°C, the film-like substance adheres closely to the surface of the translucent inorganic particles. This film-like substance functions as a protective film, suppressing the intrusion of moisture from the outside and maintaining the high luminescence efficiency of the fluorescent nanoparticles. When the film-like substance is formed by the sol-gel method, it is more preferable to include heat treatment at a temperature of 40°C to 120°C in the method for producing phosphor composite particles. The time for heat treatment after forming the film-like substance is preferably 0.5 hours to 48 hours, but may also be 0.5 hours to 24 hours. In this way, phosphor composite particles can be obtained.

[0068] Wavelength conversion component Next, a wavelength conversion member utilizing phosphor composite particles will be described. The wavelength conversion member includes phosphor composite particles and a second resin. A wavelength conversion member including phosphor composite particles and a second resin may be made by dropping a wavelength conversion member composition containing phosphor composite particles and a second resin onto a molded body having a recess of the light-emitting device of the first configuration example described later, and curing the second resin.

[0069] Second resin The second resin can be at least one resin selected from the group consisting of, for example, silicone resin, epoxy resin, phenolic resin, polycarbonate resin, acrylic resin, and modified resins thereof.

[0070] The wavelength conversion member may be in sheet form. The wavelength conversion member may be formed by creating a sheet from a composition containing phosphor composite particles and a second resin, and then curing the second resin to form a wavelength conversion sheet.

[0071] Figure 7 is a schematic cross-sectional view showing an example of the schematic configuration of a sheet-like wavelength conversion member. The wavelength conversion member 51 may comprise a wavelength conversion sheet 55 containing phosphor composite particles 1 and a second resin, and a light-transmitting member 56 containing resin. The wavelength conversion member 51 may also have the sheet-like light-transmitting member 56 on at least one surface of the wavelength conversion sheet 55 that is the incident or outgoing surface of light.

[0072] Figure 8 is a schematic cross-sectional view showing another example of the schematic configuration of a sheet-like wavelength conversion member. The wavelength conversion member 52 may include a wavelength conversion sheet 55 containing phosphor composite particles 1 and a second resin, and a sheet-like first light-transmitting member 57 and a sheet-like second light-transmitting member 58 on both the light-incident and light-exiting surfaces of the wavelength conversion sheet 55. The first light-transmitting member 57 and the second light-transmitting member 58 may have a barrier layer on the wavelength conversion sheet 55 side.

[0073] The amount of phosphor composite particles in the wavelength conversion sheet is preferably in the range of 1.0 part by mass to 20 parts by mass per 100 parts by mass of resin contained in the wavelength conversion sheet, but may also be in the range of 1.0 part by mass to 10 parts by mass, or 1.0 part by mass to 5.0 parts by mass.

[0074] The thickness of the wavelength conversion sheet is preferably in the range of 30 μm to 800 μm, more preferably in the range of 50 μm to 500 μm, and even more preferably in the range of 70 μm to 400 μm. If the thickness of the wavelength conversion sheet is within the predetermined range, a phosphor containing a quantity of phosphor composite particles that yields a desired color tone can be incorporated into the wavelength conversion sheet.

[0075] The light-transmitting member contains a resin and also functions as a protective member for the wavelength conversion sheet. The light-transmitting member may contain layers of several different types of resin and may include a barrier layer. The barrier layer may be a gas barrier layer or a water vapor barrier layer. The light-transmitting member may also have an antistatic layer or a bonding layer. The light-transmitting member may have a bonding layer between the wavelength conversion sheet and the light-transmitting member. Examples of resins constituting the light-transmitting member include polyester resins. Examples of barrier layers include those containing 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 barrier layer may contain two or more oxides. Examples of resins constituting the bonding layer include at least one resin selected from the group consisting of acrylic resins, polyisophthalate ester resins, and urethane resins. Examples of substances constituting the gas or water vapor barrier layer include inorganic oxides such as silicon dioxide and aluminum oxide. Examples of resins constituting the antistatic layer include polyimide resins.

[0076] The wavelength conversion member may contain phosphor composite particles as the first phosphor, and may also contain a phosphor having an emission peak wavelength in a wavelength range different from the emission peak wavelength of the phosphor composite particles as the second phosphor. By including the phosphor composite particles and the second phosphor having an emission peak wavelength different from that of the first phosphor in the wavelength conversion member, when the wavelength conversion member is used in a light-emitting device, desired mixed-color light can be emitted.

[0077] Second phosphor The wavelength conversion member preferably contains at least one fluoride phosphor selected from the group consisting of a fluoride phosphor having a composition represented by the following formula (2a) and a fluoride phosphor having a composition represented by the following formula (2b). A 2 g [M 3 1-f Mn 4+ f F h (2a) (In the formula (2a), A 2 is at least one selected from the group consisting of K + , Li + , Na + , Rb + , Cs + and NH4 + , M 3 contains at least one of Si and Ge at least, contains at least one element selected from the group consisting of Group 4 elements and Group 14 elements, f satisfies 0 < f < 0.2, and g is the absolute value of the charge of the [M 3 1-f Mn 4+ f F h ion, and h satisfies 5 < h < 7. ) For example, K2SiF6:Mn (also referred to as "KSF") can be mentioned. A 2 ’ g’ [M 3 ’ 1-f’ Mn 4+ f’ F h’ (2b) (In the formula (2b), A 2' is K + 、Li + 、Na + 、Rb + 、Cs + and NH4 + and includes at least one selected from the group consisting of, M 3 ' includes at least Si and Al, includes at least one element selected from the group consisting of Group 4 elements, Group 13 elements, and Group 14 elements, f' satisfies 0 < f' < 0.2, and g' is [M 3 ' 1-f’ Mn 4+ f’ F h’ and is the absolute value of the charge of the ion, and h' satisfies 5 < h' < 7. For example, K2(Si,Al)F 5.5 :Mn (also referred to as "KSAF").

[0078] The amount of the second phosphor contained in the wavelength conversion member can be appropriately selected according to the desired color tone of the mixed color light emitted from the light emitting device. The content of the second phosphor is preferably included in the range of 1.0 part by mass or more and 20 parts by mass or less, may be included in the range of 1.0 part by mass or more and 10 parts by mass or less, and may be included in the range of 1.0 part by mass or more and 5.0 part by mass or less with respect to 100 parts by mass of the resin contained in the wavelength conversion member or the wavelength conversion sheet.

[0079] The wavelength conversion member or the wavelength conversion sheet may further include a filler, a light diffusing material, etc. in addition to the resin and the phosphor. By including a filler or a light diffusing material, the directivity from the light emitting element can be relaxed and the viewing angle can be increased.

[0080] Manufacturing method of the wavelength conversion member The manufacturing method of the wavelength conversion member according to the first embodiment includes forming a wavelength conversion sheet on the surface of a translucent member using a composition for a wavelength conversion sheet including phosphor composite particles and a second resin. Examples of forming the wavelength conversion sheet include a printing method, a compression molding method, etc. When forming the wavelength conversion sheet by the printing method, the composition for the wavelength conversion sheet can be applied to a substrate by the printing method and cured to form the wavelength conversion sheet.

[0081] A method for manufacturing a wavelength conversion member according to the second embodiment includes arranging a wavelength conversion sheet composition containing phosphor composite particles and a second resin on the surface of a first translucent member, arranging a second translucent member with the wavelength conversion sheet composition sandwiched between it and the first translucent member, and joining the first translucent member and the second translucent member with a wavelength conversion sheet sandwiched between them.

[0082] The light-transmitting member, the first light-transmitting member, and the second light-transmitting member may have at least one light-transmitting member equipped with a barrier layer. If the light-transmitting member consists of multiple layers including a barrier layer, it is preferable that the barrier layer be positioned on the side closer to the wavelength conversion sheet.

[0083] The barrier layer may be formed by a vapor deposition method such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). The thickness of the barrier layer is not particularly limited, but may be in the range of 0.1 nm to 500 nm, 1 nm to 300 nm, or 5 nm to 100 nm.

[0084] Light-emitting device Next, a light-emitting device containing phosphor composite particles will be described. The light-emitting device comprises phosphor composite particles and an excitation light source. The phosphor composite particles may also be used as components of a wavelength conversion member. The light-emitting device comprises a wavelength conversion member containing phosphor composite particles and an excitation light source.

[0085] Light-emitting device of the first configuration example Embodiments of the light-emitting device will be described based on the drawings. Figure 9 is a schematic cross-sectional view showing a first configuration example of the light-emitting device.

[0086] The light-emitting device 100 comprises a molded body 40 having a recess, a light-emitting element 10 which serves as a light source, and a fluorescent member 50 which covers the light-emitting element 10. The molded body 40 is integrally molded from a first lead 20 and a second lead 30 and a resin part 42 containing a thermoplastic resin or a thermosetting resin. The molded body 40 has the first lead 20 and the second lead 30 which constitute the bottom surface of the recess, and the resin part 42 which constitutes the side surface of the recess. The light-emitting element 10 is placed on the bottom surface of the recess of the molded body 40. The light-emitting element 10 has a pair of positive and negative electrodes, and these pairs of positive and negative electrodes are electrically connected to the first lead 20 and the second lead 30, respectively, via wires 60. The light-emitting element 10 is covered with the fluorescent member 50. The fluorescent member 50 includes a phosphor 70 which converts the wavelength of light emitted by the light-emitting element 10. The phosphor 70 includes a phosphor composite particle 1 as the first phosphor 71. The phosphor 70 may include a second phosphor 72 having an emission peak wavelength that is in a different wavelength range from that of the first phosphor.

[0087] Light-emitting element A light-emitting element can be used as the light source. The light-emitting element emits light in the wavelength range of 380 nm to 500 nm. In order to efficiently excite the phosphor, the emission peak wavelength of the light-emitting element may be in the range of 400 nm to 490 nm, and more preferably in the range of 420 nm to 480 nm. In the emission spectrum of the light-emitting element, the full width at half maximum of the emission spectrum showing the maximum emission intensity can be, for example, 30 nm or less. As the semiconductor light-emitting element, for example, a semiconductor light-emitting element using a nitride-based semiconductor can be used.

[0088] Manufacturing method of the light-emitting device of the first configuration example A method for manufacturing the light-emitting device of the first configuration example will be described. Further details can be found in, for example, the disclosure in Japanese Patent Application Publication No. 2010-062272. The method for manufacturing the light-emitting device preferably includes a molded body preparation step, a light-emitting element arrangement step, a wavelength conversion member composition arrangement step, and a resin package formation step. If an aggregate molded body having a plurality of recesses is used as the molded body, a fragmentation step of separating each unit region into resin packages may be included after the resin package formation step.

[0089] In the preparation process for the molded body, multiple leads are integrally molded using a thermosetting resin or thermoplastic resin to prepare a molded body having a recess with sides and a bottom. The molded body may be a molded body consisting of an aggregate substrate containing multiple recesses. In the process of arranging the light-emitting element, the light-emitting element is placed on the bottom surface of the recess in the molded body, and the positive and negative electrodes of the light-emitting element are connected to the first lead and the second lead by wires. In the step of arranging the wavelength conversion member composition, the wavelength conversion member composition is arranged in the recess of the molded body. The wavelength conversion member composition includes phosphor composite particles as a first phosphor and a second resin, and may also include a second phosphor. In the resin package formation process, the wavelength conversion component composition placed in the recesses of the molded body is cured to form the resin package and manufacture the light-emitting device. If a molded body consisting of an aggregate substrate containing multiple recesses is used, after the resin package formation process, in the individualization process, each unit region of the aggregate substrate having multiple recesses is separated into resin packages, and individual light-emitting devices are manufactured. In this way, the light-emitting device of the first configuration example shown in Figure 9 can be manufactured.

[0090] Light-emitting device of the second configuration example Figure 10 is a schematic cross-sectional view showing a second configuration example of the light-emitting device. Figure 11 is a schematic perspective view showing a second configuration example of the light-emitting device.

[0091] The light-emitting device 200 comprises a light-emitting element 11 that serves as an excitation light source and a wavelength conversion member 51. The light-emitting device 200 of the second configuration is a side-emitting type (also called a "side-view type"). The light-emitting device 200 of the second configuration can be used, for example, in an image display device. The wavelength conversion member 51 comprises a wavelength conversion sheet 55 containing phosphor composite particles 1 and a second resin as a phosphor, and a light-transmitting member 56 on the emission side surface of the wavelength conversion sheet 55. The wavelength conversion member may be of any other form as long as it comprises a wavelength conversion sheet containing phosphor composite particles and a second resin as a first phosphor. The light-emitting element 11 is flip-chip mounted on the wiring 91 of the substrate 90 via a conductive member 61. The substrate 90 comprises the wiring 91 and a base body 92 that holds the wiring 91. The wavelength conversion member 51 is sized to cover the entire surface of the light-emitting element 11 when viewed from the front. The light incident surface 51a of the wavelength conversion member 51 is bonded to one surface of the light-emitting element 11 via the light-guiding member 62. The covering member 80 is formed on the substrate 90 and covers the sides of the conductive member 61, the light-emitting element 11, the light-guiding member 62, and the wavelength conversion member 51, completely surrounding the conductive member 61, the light-emitting element 11, the light-guiding member 62, and the wavelength conversion member 51. The front surface of the wavelength conversion member 51 and the front surface of the covering member 80 form substantially the same surface. The light-emitting element 11 can be the same type of light-emitting element as the light-emitting element 10 described above.

[0092] Light-emitting device of the third configuration example Figure 12 is a schematic cross-sectional view showing a third configuration example of the light-emitting device. Figure 13 is a schematic plan view showing a third configuration example of the light-emitting device. The light-emitting device 300 of the third configuration example is a top-view type. The light-emitting device 300 of the third configuration example can be used, for example, in an image display device. Components of the light-emitting device 300 that are common with the light-emitting device 200 of the second configuration example are denoted by the same reference numerals. The light-emitting device 300 uses, for example, a thin substrate 93 of 500 μm or less and a substrate 90 equipped with wiring 91A and 91B. The wavelength conversion member 52 includes a first translucent member 57 and a second translucent member 58 on both the incident and exit surfaces of a wavelength conversion sheet 55 containing phosphor composite particles 1 and a second resin as a phosphor. The wavelength conversion member may be of any other form, as long as it comprises a wavelength conversion sheet containing a phosphor composite particle as the first phosphor and a second resin. The light incident surface of the wavelength conversion member 52 is joined to one surface of the light-emitting element 11 via a light guide member 62. The light-emitting device 300 comprises a substrate 90 with a base 93, and other components are common to the light-emitting device 200.

[0093] Manufacturing method of the light-emitting device of the second and third configurations The manufacturing methods for the light-emitting devices of the second and third configurations can refer to the method described in Japanese Patent Application Publication No. 2017-188592. The manufacturing method for the light-emitting device of the third configuration may include a step of thinning the substrate by removing a portion of it.

[0094] The light-emitting device can be used, for example, as a backlight. By using a light-emitting element that emits blue light, a green phosphor that emits green light, and a red phosphor that emits red light, a wide range of emission colors can be produced. The phosphor composite particles used as the first phosphor can be used as the phosphor that emits green light. The second phosphor can be used as the phosphor that emits red light.

[0095] For example, in a light-emitting device used as a backlight, a wide range of emission colors can be achieved by using a light-emitting element that emits blue light, a green phosphor that emits green light, and a red phosphor that emits red light.

[0096] Image display device Next, we will describe an image display device that uses a light-emitting device.

[0097] Figure 14 is a schematic cross-sectional view showing an example of an image display device 400. The image display device 400 comprises a backlight device 160 and a display panel 170 located on the light-emitting side of the backlight device 160. The image display device 400 has a display surface 400A for displaying images. In the drawing, the surface of the display panel 170 is the display surface 400A.

[0098] The backlight device 160 illuminates the display panel 170 from the rear side in a planar manner.

[0099] Display panel The display panel 170 is a liquid crystal display panel and comprises a first polarizing sheet 140 positioned on the light-receiving side, a second polarizing sheet 150 positioned on the light-emitting side, and a liquid crystal cell 145 positioned between the first polarizing sheet 140 and the second polarizing sheet 150.

[0100] Further details regarding liquid crystal display panels can be found in various publicly available documents (for example, "Flat Panel Display Encyclopedia" (supervised by Tatsuo Uchida and Hiraki Uchiike), published by Kogyo Chosakai in 2001), and no further detailed explanation will be provided here.

[0101] Backlight device The backlight device 160 is configured as an edge-lit type backlight device and includes a housing 105, a light-emitting device 110 positioned on or away from the housing 105, a light guide plate 115 positioned to the side of the light-emitting device 110, a diffusion sheet 125 positioned on the light-emitting side of the light guide plate 115, a sheet-shaped second wavelength conversion member 130 positioned on the diffusion sheet, and a prism sheet 135 positioned on the light-emitting side of the sheet-shaped second wavelength conversion member 130. A reflective sheet 120 is provided between the housing 105 and the light guide plate 115.

[0102] The backlight device 160 has a light-emitting surface that emits light in a planar manner. In the drawing, the light-emitting surface of the prism sheet 135 is the light-emitting surface of the backlight device 160.

[0103] The side of the sheet-shaped second wavelength conversion member 130 facing the diffusion sheet 125 is the light-receiving surface, and the side of the sheet-shaped second wavelength conversion member 130 facing the prism sheet 135 is the light-emitting surface. The sheet-shaped second wavelength conversion member 130 can be the same wavelength conversion member as the wavelength conversion member according to the first and second embodiments described above, or it can be a different wavelength conversion member.

[0104] The light-emitting device 110 is constructed using a number of light-emitting elements arranged linearly along one side of the light guide plate 115 on the light-receiving surface side of the light guide plate 115. The light-emitting device 110 can use the aforementioned light-emitting devices. It may also include additional light-emitting devices that do not have wavelength conversion members.

[0105] Next, other examples of image display devices will be described using drawings. Figure 15 is a schematic cross-sectional view of an image display device showing a direct-lit backlight structure. The image display device 400E comprises a backlight device 160E and a display panel 170 positioned on the light-emitting side of the backlight device 160E, and has the same configuration as the display panel 170 described in the aforementioned image display device.

[0106] The backlight device 160E is configured as a direct-type backlight device and comprises a light-emitting device 110E, a housing 105E in which the light-emitting device 110E is arranged, a diffusion sheet 125E arranged separately from the light-emitting device 110E, a sheet-shaped second wavelength conversion member 130E arranged on the diffusion sheet, and a prism sheet 135E arranged on the light-emitting side of the sheet-shaped second wavelength conversion member 130E. The light-emitting device 110E can be the aforementioned light-emitting device. A reflective sheet 120E is provided between the housing 105E and the light guide plate 115E.

[0107] Reflective sheet The reflective sheet reflects the light emitted from the light-emitting device 110E to the back side, directs it to the light guide plate 115E, the diffusion sheet 125E, etc., and efficiently utilizes the light that passes through to the back side.

[0108] In this manner, the light emitted from the backlight device 160E is received by the first polarizing sheet 140 provided on the display panel 170 and emitted from the display surface 400A of the image display device.

[0109] [Section 1] The material comprises translucent inorganic particles with a volume-average particle size in the range of 30 nm to 500 nm, fluorescent nanoparticles with an average particle size in the range of 5 nm to 25 nm, and a first resin. A phosphor composite particle having a volume-average particle size in the range of 0.5 μm to 50 μm, wherein at least a portion of the translucent inorganic particles are embedded in the first resin and unevenly distributed on the particle surface. [Section 2] The material comprises translucent inorganic particles with a volume-average particle size in the range of 30 nm to 500 nm, fluorescent nanoparticles with an average particle size in the range of 5 nm to 25 nm, and a first resin. A phosphor composite particle comprising at least a portion of the translucent inorganic particles embedded in the first resin and unevenly distributed on the particle surface, a film-like material containing an inorganic substance that transmits light with a wavelength of 400 nm or more on at least a portion of the surface of the translucent inorganic particles, and a volume-average particle size in the range of 0.5 μm to 50 μm. [Section 3] The phosphor composite particle according to claim 1 or 2, wherein the first resin comprises a polymer obtained by polymerizing a radically polymerizable monomer. [Section 4] The phosphor composite particle according to claim 3, wherein the radical polymerizable monomer is at least one monomer selected from the group consisting of acrylate, methacrylate, styrene, butadiene, isoprene, maleic anhydride, maleic acid derivatives, and fumaric acid derivatives. [Section 5] The phosphor composite particle according to any one of claims 1 to 4, wherein the translucent inorganic particles are at least one oxide or fluoride selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride. [Section 6] The fluorescent composite particle according to any one of claims 1 to 5, wherein the fluorescent nanoparticle comprises a compound having a composition represented by the following formula (1). [M 1 d A 1 e ] a M 2 b X c (1) (In the above formula (1), M 1 is at least one first element selected from the group consisting of Cs, Rb, K, Na, and Li, and A 1 M is at least one organic cation selected from the group consisting of ammonium ions, formamidinium ions, guanidinium ions, imidazolium ions, pyridinium ions, pyrrolidinium ions, and protonated thiourea ions. 2 (where X is at least one secondary element selected from the group consisting of Ge, Sn, Pb, Sb, and Bi; X is an anion or ligand selected from the group consisting of chlorides, bromides, iodines, cyanides, thiocyanates, isothiocyanates, and sulfides; a is an integer from 1 to 4; b is an integer from 1 to 2; c is an integer from 3 to 9; d is from 0 to 1; e is from 0 to 1; and d+e=1.) [Section 7] The phosphor composite particles according to any one of items 1 to 6, wherein the fluorescent nanoparticles contain a compound having a chalcopyrite-type crystal structure. [Item 8] The phosphor composite particles according to item 2, wherein the film-like substance is composed of at least one inorganic substance selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride. [Item 9] A wavelength conversion member comprising the phosphor composite particles according to any one of items 1 to 8 and a second resin. [Item 10] The wavelength conversion member according to item 9, wherein the wavelength conversion member is sheet-shaped. [Item 11] The wavelength conversion member according to item 9 or item 10, wherein the wavelength conversion member further contains at least one fluoride phosphor selected from the group consisting of a fluoride phosphor having a composition represented by the following formula (2a) and a fluoride phosphor having a composition represented by the following formula (2b). A 2 g [M 3 1-f Mn 4+ f F h (2a) (In the formula (2a), A 2 includes at least one selected from the group consisting of K + , Li + , Na + , Rb + , Cs + and NH4 + , M 3 includes at least one element selected from the group consisting of a Group 4 element and a Group 14 element, f satisfies 0 < f < 0.2, g is the absolute value of the charge of the [M 3 1-f Mn 4+ f F h ion, and h satisfies 5 < h < 7.) A 2 ’ g’ [M 3 ’ 1-f’ Mn 4+ f’ Fh’ (2b) (In the formula (2b), A 2 ’ is at least one selected from the group consisting of K + , Li + , Na + , Rb + , Cs + and NH4 + and contains at least one selected from the group consisting of M 3 ’ contains at least one element selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, f’ satisfies 0 < f’ < 0.2, and g’ is [M 3 ’ 1-f’ Mn 4+ f’ F h’ is the absolute value of the charge of the ion, and h’ satisfies 5 < h’ < 7.) [Item 12] A light-emitting device including the phosphor composite particles according to any one of Items 1 to 8 and an excitation light source. [Item 13] A light-emitting device including the wavelength conversion member according to any one of Items 9 to 11 and an excitation light source. [Item 14] Preparing a first dispersion serving as a dispersed phase, including fluorescent nanoparticles, a radically polymerizable monomer, and a polymerization initiator; Preparing a second dispersion serving as a continuous phase, including a suspension stabilizer containing translucent inorganic particles and an organic solvent; Mixing the first dispersion and the second dispersion and performing suspension polymerization, When the radically polymerizable monomer is polymerized and particles of a first resin containing the fluorescent nanoparticles are formed, at least a part of the translucent inorganic particles is embedded in the first resin by a pickering emulsion in which the translucent inorganic particles are present at an oil / oil interface, and a phosphor composite particle in which the particles are unevenly distributed on the surface is obtained. A method for producing a phosphor composite particle. [Item 15] The method for producing a phosphor composite particle according to Item 14, including attaching a film-like substance containing an inorganic substance that transmits light having a wavelength of 400 nm or more to at least a part of the surface of the translucent inorganic particles. [Item 16] A method for producing phosphor composite particles according to item 15, wherein the aforementioned film-like material is attached by a sol-gel method. [Section 17] A method for producing phosphor composite particles according to item 15, wherein the aforementioned film-like material is attached by atomic deposition. [Section 18] A method for producing phosphor composite particles according to any one of claims 14 to 17, wherein the first dispersion has a content of fluorescent nanoparticles in the range of 0.5% by mass or more and 10.0% by mass or less, a content of the radical polymerizable monomer in the range of 90% by mass or more and 99.5% by mass or less, and a content of the polymerization initiator in the range of 0.5% by mass or more and 2.0% by mass or less, based on the total amount of the first dispersion. [Section 19] The method for producing phosphor composite particles according to any one of claims 14 to 18, wherein the second dispersion contains the translucent inorganic particles in an amount of 0.5 parts by mass or more and 10.0 parts by mass or less, per 100 parts by mass of the total amount of the first dispersion. [Section 20] A method for producing phosphor composite particles according to any one of claims 14 to 19, wherein the organic solvent is at least one selected from the group consisting of dimethyl silicone oil, methylphenyl silicone oil, organically modified silicone oil, hydrofluoroether, and fluorinated hydrocarbons. [Section 21] A method for producing phosphor composite particles according to any one of claims 14 to 20, wherein the translucent inorganic particles are at least one oxide or fluoride selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride. [Section 22] A method for producing phosphor composite particles according to any one of claims 14 to 21, wherein the radical polymerizable monomer is at least one monomer selected from the group consisting of acrylate, methacrylate, styrene, butadiene, isoprene, maleic anhydride, maleic acid derivatives, and fumaric acid derivatives. [Section 23] A method for producing phosphor composite particles according to any one of claims 14 to 22, wherein the fluorescent nanoparticles include a compound having a composition represented by the following formula (1). [M 1 d A 1 e ] a M 2 b X c (1) (In the above formula (1), M 1 is at least one first element selected from the group consisting of Cs, Rb, K, Na, and Li, and A 1 M is at least one organic cation selected from the group consisting of ammonium ions, formamidinium ions, guanidinium ions, imidazolium ions, pyridinium ions, pyrrolidinium ions, and protonated thiourea ions. 2 (where is at least one secondary element selected from the group consisting of Ge, Sn, Pb, Sb, and Bi; X is an anion or ligand selected from the group consisting of chlorides, bromides, iodines, cyanides, thiocyanates, isothiocyanates, and sulfides; a is an integer from 1 to 4; b is an integer from 1 to 2; c is an integer from 3 to 9; d is from 0 to 1; e is from 0 to 1; and d+e=1.) [Section 24] A method for producing phosphor composite particles according to any one of claims 15 to 23, wherein the film-like material consists of at least one inorganic substance selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride. [Section 25] A method for manufacturing a wavelength conversion member, comprising forming a wavelength conversion sheet on the surface of a light-transmitting member using a wavelength conversion sheet composition comprising phosphor composite particles manufactured by the method described in any one of claims 14 to 24 and a second resin. [Section 26] A method for manufacturing a wavelength conversion member, comprising: arranging a wavelength conversion sheet composition comprising phosphor composite particles manufactured by the method described in any one of claims 14 to 24 and a second resin on the surface of a first light-transmitting member; arranging a second light-transmitting member with the wavelength conversion sheet composition sandwiched between it and the first light-transmitting member; and joining the first light-transmitting member and the second light-transmitting member with a wavelength conversion sheet sandwiched between them. [Examples]

[0110] The present invention will be described in detail below with reference to examples. The present invention is not limited to these examples.

[0111] The reagents and other materials used in the examples and comparative examples are as follows: Formamidinium hydrobromide (FABr) (manufactured by Tokyo Chemical Industry Co., Ltd.) Lead(II) Bromide (PbBr2) (manufactured by Strem Chemicals) Octadecyldimethyl(3-sulfopropyl)ammonium hydroxide (SBE-18) (manufactured by Merck KGaA) Oleylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) Hexane (manufactured by Fujifilm Wako Pure Chemical Corporation) Toluene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Tricyclodecanedimethanol diacrylate (A-DCP, Shin-Nakamura Chemical Industry Co., Ltd.) Dicyclopentanyl acrylate (FA-513AS, manufactured by Showa Denko Materials Co., Ltd.) EO-modified bisphenol A dimethacrylate (FA-320M, manufactured by Showa Denko Materials Co., Ltd.) EO-modified bisphenol A dimethacrylate (FA-321M, manufactured by Showa Denko Materials Co., Ltd.) Silica particles (average particle size 110 nm (catalog value) as determined by laser diffraction scattering method, product name QSG-100, manufactured by Shin-Etsu Chemical Co., Ltd.) Dimethyl silicone oil (KF-96-3000cs, manufactured by Shin-Etsu Chemical Co., Ltd.) Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 10mm diameter (φ10mm) zirconia ball YTZ (yttria-stabilized zirconia) (manufactured by AS ONE Corporation) 4mm diameter (φ4mm) zirconia ball YTZ (yttria-stabilized zirconia) (manufactured by AS ONE Corporation) 2mm diameter (φ2mm) zirconia ball YTZ (yttria-stabilized zirconia) (manufactured by AS ONE Corporation) 0.2mm diameter (φ0.2mm) zirconia ball YTZ (yttria-stabilized zirconia) (manufactured by AS ONE Corporation)

[0112] The equipment used to manufacture fluorescent nanoparticles and phosphor composite particles is as follows: Ball mill rotating stand (AV-1, manufactured by AS ONE Corporation) Wet-type micro-bead mill grinding and dispersing machine (Labostar Mini, manufactured by Ashizawa Finetech Co., Ltd.) Evaporator (R-205, manufactured by Buchi) Rotation and Revolution Mixer (AR-250, manufactured by Thinky Co., Ltd.) UV irradiation unit (SUV-008, manufactured by Sen Special Light Source Co., Ltd.) Centrifuge (CN-2060, rotation radius 94mm, manufactured by AS ONE Corporation)

[0113] Fluorescent nanoparticle precursor The following ingredients were placed in an alumina pot. Formamidinium hydrobromide (FABr): 25,200g Lead(II) bromide (PbBr2): 74.2g, 10mm diameter zirconia balls YTZ: 22.600g Zirconia ball YTZ, 2mm diameter: 5.6g The alumina pot containing the raw materials was mounted on a ball mill rotating stand, and the raw materials were mixed at a rotation speed of 160 rpm for 48 hours. 50g of hexane was added as an organic solvent to the alumina pot containing the raw materials, and the raw materials were mixed for a further 3 hours at a rotation speed of 160 rpm. After the mixing of the raw materials was completed, the mixture obtained by suction filtration was passed through a nylon mesh with a mesh size of 300 μm to remove the zirconia balls YTZ and obtain a slurry-like first mixture. This first mixture was then filtered by suction and air-dried for 24 hours to obtain a fluorescent nanoparticle precursor. The fluorescent nanoparticle precursor has a composition represented by [(NH2)2CH]PbBr3 (hereinafter also referred to as "FAPbBr3"). The fluorescent nanoparticle precursor was orange in color. The fluorescent nanoparticle precursor did not emit light when irradiated with light from an excitation light source.

[0114] Measurement of X-ray diffraction patterns The X-ray diffraction (XRD) patterns of fluorescent nanoparticle precursors were measured using CuKα-based X-ray diffraction (XRD). An X-ray diffractometer (MiniFlex, Rigaku Corporation) was used to measure the XRD patterns, which represent the diffraction intensity against the diffraction angle (2θ). Figure 16 shows the XRD patterns of a fluorescent nanoparticle precursor with a composition represented by FAPbBr3 and the XRD patterns of FAPbBr3 with an orthorhombic crystal structure registered in the ICSD (Inorganic Crystal Structure Database).

[0115] As shown in Figure 16, the peak positions of the XRD pattern of the fluorescent nanoparticle precursor coincided with the peak positions of the XRD pattern of FAPbBr3 registered in ICSD. The XRD pattern results confirmed that the fluorescent nanoparticle precursor has an orthorhombic crystal structure.

[0116] Fluorescent nanoparticles 4.40 g of fluorescent nanoparticle precursor, 1.30 g of oleylamine, 0.40 g of octadecyldimethyl(3-sulfopropyl)ammonium hydroxide (SBE-18) as organic solvents, and 432.00 g of toluene, along with 442.00 g of zirconia balls YTZ with a diameter of 0.2 mm as a dispersion medium, were placed in a wet micro-bead mill grinding and dispersing machine and stirred for 1 hour at a peripheral speed of 14 m / sec and a rotation speed of 4456 rpm. The mixture obtained by stirring was filtered through a 25 μm mesh nylon net by suction filtration to remove the zirconia balls YTZ and unground coarse fluorescent nanoparticle precursors, yielding a slurry-like second mixture. The second mixture was placed in a container and centrifuged at 5000 rpm for 10 minutes using the aforementioned centrifuge to allow the coarse particles to settle, and the supernatant was collected. The obtained supernatant was passed through a syringe filter with a pore size of 0.2 μm to obtain a solution containing fluorescent nanoparticles. The fluorescent nanoparticle content in the solution was 1.0 mass%. When the solution containing fluorescent nanoparticles was irradiated with light, the solution emitted light.

[0117] Luminescence characteristics The luminescence properties of a solution containing fluorescent nanoparticles (fluorescent nanoparticle content 1.0 mass%) were measured. Using a quantum efficiency meter (QE-2100, manufactured by Otsuka Electronics Co., Ltd.), excitation light with an emission peak wavelength of 450 nm was irradiated onto the solution containing fluorescent nanoparticles. The solution containing fluorescent nanoparticles was diluted with a solvent (toluene) to an absorbance of 0.15 at 450 nm, and the emission spectrum at room temperature (25°C) was measured. From the obtained emission spectrum, the internal quantum efficiency (%), emission peak wavelength (nm), and full width at half maximum (nm) of the emission spectrum with the emission peak wavelength were determined. The internal quantum efficiency (%) is the ratio of photons converted to emission out of the photons absorbed by the fluorescent nanoparticles, and was calculated by dividing the number of emitted photons (%) by the number of absorbed photons (%). The luminescence properties of the fluorescent nanoparticles are shown in Table 1.

[0118] Fluorescent nanoparticles in solution were observed using a transmission electron microscope (TEM) (H-7650, Hitachi High-Technologies Corporation). Figure 17 is a TEM image of the fluorescent nanoparticles in solution.

[0119] Average particle size of fluorescent nanoparticles The average particle size of fluorescent nanoparticles in solution was measured from TEM images at magnifications of 80,000 to 200,000 times the average particle size. The TEM grid used was the Hi-Res Carbon HRC-C10 STEM Cu100P grid (manufactured by Ouken Shoji Co., Ltd.). The resulting particles were either spherical or polygonal. The average particle size was calculated by selecting TEM images from three or more locations, measuring the particle sizes of all measurable fluorescent nanoparticles included in these images, and taking the arithmetic mean. The average particle size of a fluorescent nanoparticle is defined as the longest line segment connecting any two points on the outer circumference of the particle observed in the TEM image, passing through the center of the particle. Fluorescent nanoparticles whose images were cut off at the edges of the TEM image were excluded from the particle size measurement. Specifically, the particle sizes of a total of 100 or more fluorescent nanoparticles were measured using TEM images from three or more locations. The average particle sizes are shown in Table 1.

[0120] [Table 1]

[0121] The fluorescent nanoparticles exhibited high emission characteristics with an internal quantum efficiency of 76%, a narrow full width at half maximum of 50 nm, and excellent color purity. Furthermore, in the emission spectrum of the fluorescent nanoparticles, the emission peak wavelength was 517 nm, and they absorbed excitation light with an emission peak wavelength of 450 nm, resulting in green emission.

[0122] Phosphor composite particles of Example 1 Preparation of the first dispersion A solution was prepared by mixing 12,000 g of a solution containing fluorescent nanoparticles (fluorescent nanoparticle content 1.0 mass%) with 5,880 g of tricyclodecanedimethanol diacrylate (A-DCP) as a radical polymerizable monomer. This solution was reduced to 20 mbar using an evaporator, and toluene was evaporated over 15 minutes while heating at 70°C to obtain an A-DCP dispersion containing fluorescent nanoparticles. This A-DCP dispersion containing fluorescent nanoparticles (5,000 g) and 0.050 g of diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide (TPO) as a photopolymerization initiator were mixed at room temperature (25°C) for 5 hours to obtain a first dispersion, which would become the dispersed phase.

[0123] Preparation of the second dispersion 0.120 g of silica particles (QSG-100) with a volume-average particle size of 110 nm as translucent inorganic particles and 16.230 g of dimethyl silicone oil (KF-96-3000cs) as an organic solvent were stirred in a rotary-orbit mixer for 3 minutes, and then degassed for 1 minute to obtain a second dispersion in which silica particles were dispersed in dimethyl silicone oil.

[0124] Suspension polymerization A first dispersion (2.000 g) containing fluorescent nanoparticles, a radical polymerizable monomer, and a photopolymerization initiator, and a second dispersion (16.350 g) containing translucent inorganic particles and an organic solvent were stirred for 3 minutes in a rotary-orbit mixer to form an emulsion in which the first dispersion became the dispersed phase and the second dispersion became the continuous phase. The emulsion was placed in a petri dish so that its thickness was 1 mm. The emulsion was irradiated with ultraviolet light from a UV irradiator to initiate the polymerization reaction of the radical polymerizable monomer. Translucent inorganic particles were adsorbed by the Pickering emulsion at the oil / oil interface between the continuous phase and the droplets of the dispersed radical polymerizable monomer. The radical polymerizable monomer was then cured by the polymerization reaction to form particles of a first resin containing fluorescent nanoparticles. At least a portion of the translucent inorganic particles were embedded in the first resin and unevenly distributed on the particle surface to obtain phosphor composite particles.

[0125] Washing and drying The obtained phosphor composite particles were washed with 35 mL of hexane. After washing, the phosphor composite particles were centrifuged at 5000 rpm for 5 minutes using a centrifuge to allow them to settle. The supernatant was removed to separate the solid and liquid components and obtain a precipitate. The obtained precipitate was washed with hexane and then subjected to solid-liquid separation using a centrifuge, repeating this process three times in that order. The resulting precipitate was then washed with 50 mL of hexane for 2 hours. After stirring, the phosphor composite particles were centrifuged at 5000 rpm for 5 minutes using a centrifuge to settle, and the supernatant was removed to separate the solid and liquid components, yielding a precipitate. This precipitate was air-dried in an atmospheric environment for 15 hours to obtain the phosphor composite particles of Example 1.

[0126] Phosphor composite particles of Example 2 The phosphor composite particles of Example 2 were obtained in the same manner as in Example 1, except that tricyclodecanedimethanol diacrylate (A-DCP) and EO-modified bisphenol A dimethacrylate (FA-320M) were used as radical polymerizable monomers in a mass ratio of 70:30.

[0127] Phosphor composite particles of Example 3 The phosphor composite particles of Example 3 were obtained in the same manner as in Example 1, except that tricyclodecanedimethanol diacrylate (A-DCP) and EO-modified bisphenol A dimethacrylate (FA-321M) were used as radical polymerizable monomers in a mass ratio of 70:30.

[0128] Luminescence properties of phosphor composite particles For each phosphor composite particle in the examples, the internal quantum efficiency (%), emission peak wavelength (nm), and full width at half maximum (nm) of the emission spectrum with the emission peak wavelength were determined in the same manner as when measuring fluorescent nanoparticles. The emission characteristics of the phosphor composite particles are shown in Table 2.

[0129] Volume-average particle size of phosphor composite particles For each of the phosphor composite particles in the examples, the average particle size was measured using a laser diffraction particle size distribution analyzer (MASTER SIZER2000, MALVERN) by determining the cumulative 50% particle size from the smallest diameter side in the volume-based particle size distribution (median diameter). The results are shown in Table 2.

[0130] SEM photo-backscattered electron image A scanning electron microscope (FE-SEM, SU3500, manufactured by Hitachi High-Technologies Corporation) was used to obtain SEM images of the phosphor composite particles, which are backscattered electron images. Figure 18 is an SEM image (backscattered electron image) of the phosphor composite particles of Example 1. Figure 19 is a magnified view of a portion of the SEM image (backscattered electron image) of Figure 18.

[0131] SEM photo-backscattered electron image The phosphor composite particles according to Example 1 were embedded in epoxy resin, and after the resin was cured, the cross-section of the phosphor composite particles was cut to expose it. The surface was then polished with sandpaper, and the surface was finished with a cross-section polisher (CP). An SEM image of the backscattered electron image of the cross-section of the phosphor composite particles according to Example 1 was obtained using a field emission scanning electron microscope (FE-SEM, SU8230, manufactured by Hitachi High-Technologies Corporation). Figure 20 is an SEM image (backscattered electron image) of the cross-section of the phosphor composite particles of Example 1. Figure 21 is a magnified view of a part of the SEM image (backscattered electron image) of Figure 20.

[0132] [Table 2]

[0133] Each of the phosphor composite particles in Examples 1 to 3 had high luminescence characteristics with an internal quantum efficiency of 62% or 66%. Each of the phosphor composite particles in Examples 1 to 3 had a narrow full width at half maximum of 31 nm and excellent color purity. Each of the phosphor composite particles in Examples 1 to 3 had an emission peak wavelength of 525 nm or 526 nm in the emission spectrum of the phosphor composite particle, and emitted green light when absorbing excitation light with an emission peak wavelength of 450 nm. Each of the phosphor composite particles in Examples 1 to 3 had a volume average particle size in the range of 0.5 μm to 50 μm.

[0134] Figures 18 and 19 are SEM images (backscattered electron images) of the phosphor composite particles according to Example 1. It was confirmed that the phosphor composite particles had translucent inorganic particles embedded almost completely on their surface.

[0135] Figures 20 and 21 are SEM images (backscattered electron images) of the cross-section of the phosphor composite particles according to Example 1. It was confirmed that at least a portion of the translucent inorganic particles 2 of the phosphor composite particle 1 are embedded in the first resin 4 and are unevenly distributed on the particle surface.

[0136] Wavelength conversion member of Example 1 A composition for a wavelength conversion sheet was prepared by mixing 0.3 g of the phosphor composite particles according to Example 1, 0.693 g of the resin dicyclopentanyl acrylate (FA-513AS), 0.297 g of EO-modified bisphenol A dimethacrylate (FA-321M), and 0.010 g of the photoinitiation polymerization initiator diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide (TPO). A first translucent member was prepared, comprising a gas barrier layer made of silicon dioxide and a layer made of polyethylene terephthalate. The thickness of the first translucent member was 120 μm. 0.140 g of the wavelength conversion sheet composition was applied to the surface of the first translucent member near the gas barrier layer using a squeegee by printing. The surface of the second translucent member near the gas barrier layer, similar to that of the first translucent member, was placed on the side of the wavelength conversion sheet composition. The wavelength conversion sheet composition was sandwiched between the first and second translucent members, and ultraviolet light was irradiated from a UV irradiator to initiate the polymerization reaction of the resin and cure it. The first and second translucent members were joined with a wavelength conversion sheet 80 μm thick sandwiched in between to produce the wavelength conversion member according to Example 1. The concentration of fluorescent nanoparticles in the wavelength conversion member was 0.6% by mass relative to the total amount of the wavelength conversion sheet composition. The wavelength conversion member according to Example 1 includes a gas barrier layer between the first translucent member and the wavelength conversion sheet, and between the second translucent member and the wavelength conversion sheet.

[0137] Wavelength conversion member of Example 2 The wavelength conversion member of Example 2 was manufactured in the same manner as the wavelength conversion member of Example 1, except that the phosphor composite particles according to Example 2 were used.

[0138] Wavelength conversion member of Example 3 The wavelength conversion member of Example 3 was manufactured in the same manner as the wavelength conversion member of Example 1, except that the phosphor composite particles according to Example 3 were used.

[0139] Wavelength conversion member of Comparative Example 1 A solution was prepared by mixing 12.000 g of the aforementioned solution containing fluorescent nanoparticles (fluorescent nanoparticle content 1.0% by mass) with 5.880 g of the resin dicyclopentanyl acrylate (FA-513AS). This solution was reduced to 20 mbar using an evaporator, and toluene was evaporated over 15 minutes while heating at 70°C to obtain an FA-513AS dispersion containing fluorescent nanoparticles. To this FA-513AS dispersion (0.300 g) containing fluorescent nanoparticles, 0.399 g of the resin FA-513AS, 0.297 g of EO-modified bisphenol A dimethacrylate (FA-321M), and 0.010 g of diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide (TPO) as a photopolymerization initiator to prepare a wavelength conversion sheet composition. The wavelength conversion member of Comparative Example 1 was manufactured in the same manner as the wavelength conversion member of Example 1, except that this wavelength conversion sheet composition was used. The concentration of fluorescent nanoparticles in the wavelength conversion member was 0.6% by mass relative to the total amount of the composition for the wavelength conversion sheet.

[0140] Luminous intensity maintenance rate (%) The wavelength conversion members of the examples and comparative examples were evaluated as follows. Each wavelength conversion member in the examples and comparative examples was placed in a constant temperature and humidity chamber (manufactured by ESPEC Corporation) at a temperature of 60°C and a relative humidity of 90%. The emission intensity of the wavelength conversion members was measured after 1 hour, 3 hours, 8 hours, 24 hours, and 48 hours. To measure the emission intensity of the wavelength conversion members, the wavelength conversion member was placed on a backlight source with an emission peak wavelength of 450 nm, a prism sheet and a polarizing sheet were placed on top, and the emission spectrum at room temperature (25°C) was measured using a spectrophotometer. The maximum emission intensity was taken as the emission intensity of the wavelength conversion member after each time period. The emission intensity of the wavelength conversion member before being placed in the constant temperature and humidity chamber was taken as the emission intensity at 0 hours, with the emission intensity at 0 hours set to 100%, and the percentage of the emission intensity of the wavelength conversion member after each time period in the constant temperature and humidity chamber was calculated as the emission intensity maintenance rate (%). The results are shown in Figure 22.

[0141] Figure 22 shows the relationship between time and emission intensity maintenance rate (%) for the wavelength conversion members in Examples 1 to 3 and Comparative Example 1. The wavelength conversion member according to Example 1 maintained a luminescence intensity retention rate of 100% or more even after 24 hours in a constant temperature and humidity chamber. From this result, it was confirmed that the wavelength conversion member using phosphor composite particles according to Example 1 maintains the high luminescence intensity of the fluorescent nanoparticles. The wavelength conversion member according to Example 2 maintained a luminescence intensity retention rate of 100% or more even after 24 hours in a constant temperature and humidity chamber. From this result, it was confirmed that the wavelength conversion member using phosphor composite particles according to Example 2 maintains the high luminescence intensity of the fluorescent nanoparticles. The wavelength conversion member according to Example 3 maintained a luminescence intensity retention rate of 90% or more even after 24 hours in a constant temperature and humidity chamber. From this result, it was confirmed that the wavelength conversion member using phosphor composite particles according to Example 3 maintains the high luminescence intensity of the fluorescent nanoparticles.

[0142] On the other hand, the wavelength conversion member according to Comparative Example 1 showed a luminescence intensity maintenance rate of less than 80% after 24 hours, indicating that it was unable to maintain the luminescence intensity of the fluorescent nanoparticles. [Industrial applicability]

[0143] The phosphor composite particles, wavelength conversion member, and light-emitting device according to the embodiments of this disclosure are useful for various lighting light sources, automotive light sources, display light sources, etc. In particular, they are advantageously applicable to backlight units of image display devices using liquid crystals. The light-emitting device according to the embodiments of this disclosure is also advantageous for backlights of display devices for mobile devices. It can be used as a light-emitting device for general lighting and a light-emitting device for vehicles. [Explanation of Symbols]

[0144] 1: Phosphor composite particles, 2: Translucent inorganic particles, 3: Fluorescent nanoparticles, 4: First resin, 5: Film-like material, 10, 11: Light-emitting element, 20: First lead, 30: Second lead, 40: Molded body, 42: Resin part, 50: Fluorescent component, 51, 52: Wavelength conversion component, 55: Wavelength conversion sheet, 56: Translucent component, 57: First translucent component, 58: Second translucent component, 60: Wire, 61: Conductive component, 62: Light guide component, 70: Phosphor, 71: First phosphor, 72: Second phosphor, 80: Coating component, 90 : Substrate, 100, 200, 300: Light-emitting device, 105, 105E: Housing, 110, 110E: Light-emitting device, 115, 115E: Light guide plate, 120, 120E: Reflective sheet, 125, 125E: Diffusing sheet, 130, 130E: Sheet-shaped 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, 400, 400E: Image display device.

Claims

1. The material comprises translucent inorganic particles with a volume-average particle size in the range of 30 nm to 500 nm, fluorescent nanoparticles with an average particle size in the range of 5 nm to 25 nm, and a first resin. At least a portion of the translucent inorganic particles are embedded in the first resin and unevenly distributed on the particle surface, with a volume-average particle size in the range of 0.5 μm to 50 μm. The first resin comprises a polymer obtained by polymerizing a radically polymerizable monomer, The radical polymerizable monomer is at least one monomer selected from the group consisting of acrylate, methacrylate, styrene, butadiene, isoprene, maleic anhydride, maleic acid derivatives, and fumaric acid derivatives. Phosphor composite particles wherein the translucent inorganic particles are at least one oxide or fluoride selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride.

2. The material comprises translucent inorganic particles with a volume-average particle size in the range of 30 nm to 500 nm, fluorescent nanoparticles with an average particle size in the range of 5 nm to 25 nm, and a first resin. At least a portion of the translucent inorganic particles are embedded in the first resin and unevenly distributed on the particle surface, and at least a portion of the surface of the translucent inorganic particles is provided with a film-like material containing an inorganic substance that transmits light with a wavelength of 400 nm or more, and the volume average particle size is in the range of 0.5 μm to 50 μm. The first resin comprises a polymer obtained by polymerizing a radically polymerizable monomer, The radical polymerizable monomer is at least one monomer selected from the group consisting of acrylate, methacrylate, styrene, butadiene, isoprene, maleic anhydride, maleic acid derivatives, and fumaric acid derivatives. Phosphor composite particles wherein the translucent inorganic particles are at least one oxide or fluoride selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride.

3. The fluorescent composite particle according to claim 1 or 2, wherein the fluorescent nanoparticle comprises a compound having a composition represented by the following formula (1). [M １ ｄ A １ ｅ ] ａ M ２ ｂ X ｃ (1) (In the above formula (1), M １ is at least one first element selected from the group consisting of Cs, Rb, K, Na, and Li, A １ is at least one organic cation selected from the group consisting of ammonium ion, formamidinium ion, guanidinium ion, imidazolium ion, pyridinium ion, pyrrolidinium ion, and protonated thiourea ion, M ２ is at least one second element selected from the group consisting of Ge, Sn, Pb, Sb, and Bi, X is an anion or ligand selected from the group consisting of chloride, bromide, iodide, cyanide, thiocyanate, isothiocyanate, and sulfide, a is an integer from 1 to 4, b is an integer from 1 to 2, c is an integer from 3 to 9, d is from 0 to 1, e is from 0 to 1, and d + e = 1.)

4. The fluorescent composite particle according to claim 1 or 2, wherein the fluorescent nanoparticle comprises a compound having a chalcopyrite-type crystal structure.

5. The phosphor composite particle according to claim 2, wherein the film-like material consists of at least one inorganic substance selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride.

6. A wavelength conversion member comprising phosphor composite particles according to claim 1 or 2 and a second resin.

7. The wavelength conversion member according to claim 6, wherein the wavelength conversion member is in the form of a sheet.

8. The wavelength conversion member according to claim 6, further comprising at least one fluoride phosphor selected from the group consisting of a fluoride phosphor having a composition represented by the following formula (2a) and a fluoride phosphor having a composition represented by the following formula (2b). A ２ ｇ [M ３ １－ｆ Mn ４＋ ｆ F ｈ ] (2a) (In the above formula (2a), A ２ is, K ＋ Li ＋ Na ＋ , Rb ＋ , Cs ＋ and NH ４ ＋ It includes at least one selected from the group consisting of M ３ It includes at least one element selected from the group consisting of Group 4 and Group 14 elements, f satisfies 0 < f < 0.2, and g is [M ３ １－ｆ Mn ４＋ ｆ F ｈ (This is the absolute value of the ion's charge, where h satisfies 5 < h < 7.) A ２ ’ ｇ’ [M ３ ’ １－ｆ’ Mn ４＋ ｆ’ F ｈ’ ] (2b) (In the above formula (2b), A ２ ' is K ＋ Li ＋ Na ＋ , Rb ＋ , Cs ＋ and NH ４ ＋ It includes at least one selected from the group consisting of M ３ ' contains at least one element selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, f' satisfies 0 < f' < 0.2, and g' is [M ３ ' １－ｆ’ Mn ４＋ ｆ’ F ｈ’ (This is the absolute value of the ion's charge, and h' satisfies the condition 5 < h' < 7.)

9. A light-emitting device comprising phosphor composite particles according to claim 1 or 2 and an excitation light source.

10. A light-emitting device comprising the wavelength conversion member described in Claim 6 and an excitation light source.

11. Prepare a first dispersion that will be the dispersed phase, containing fluorescent nanoparticles, a radical polymerizable monomer, and a polymerization initiator. Prepare a second dispersion that forms a continuous phase, containing a suspension stabilizer with translucent inorganic particles and an organic solvent. The process includes mixing the first dispersion and the second dispersion and performing suspension polymerization. When the radical polymerizable monomer is polymerized to form particles of the first resin containing the fluorescent nanoparticles, a Pickering emulsion in which the translucent inorganic particles are present at the oil / oil interface allows for the formation of phosphorescent composite particles in which at least a portion of the translucent inorganic particles are embedded in the first resin and unevenly distributed on the particle surface. The radical polymerizable monomer is at least one monomer selected from the group consisting of acrylate, methacrylate, styrene, butadiene, isoprene, maleic anhydride, maleic acid derivatives, and fumaric acid derivatives. A method for producing phosphor composite particles, wherein the translucent inorganic particles are at least one oxide or fluoride selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride.

12. A method for producing phosphor composite particles according to claim 11, comprising attaching a film-like material containing an inorganic substance that transmits light with a wavelength of 400 nm or more to at least a portion of the surface of the translucent inorganic particles.

13. A method for producing phosphor composite particles according to claim 12, wherein the aforementioned film-like material is attached by a sol-gel method.

14. A method for producing phosphor composite particles according to claim 12, wherein the aforementioned film-like material is attached by atomic deposition.

15. A method for producing phosphor composite particles according to claim 11 or 12, wherein the first dispersion has a content of fluorescent nanoparticles in the range of 0.5% by mass or more and 10.0% by mass or less, a content of the radical polymerizable monomer in the range of 90% by mass or more and 99.5% by mass or less, and a content of the polymerization initiator in the range of 0.5% by mass or more and 2.0% by mass or less, based on the total amount of the first dispersion.

16. The method for producing phosphor composite particles according to claim 11 or 12, wherein the second dispersion contains the translucent inorganic particles in an amount of 0.5 parts by mass or more and 10.0 parts by mass or less, based on 100 parts by mass of the total amount of the first dispersion.

17. The method for producing phosphor composite particles according to claim 11 or 12, wherein the organic solvent is at least one selected from the group consisting of dimethyl silicone oil, methylphenyl silicone oil, organically modified silicone oil, hydrofluoroether, and fluorinated hydrocarbon.

18. A method for producing phosphor composite particles according to claim 11 or 12, wherein the fluorescent nanoparticles include a compound having a composition represented by the following formula (1). [M １ ｄ A １ ｅ ] ａ M ２ ｂ X ｃ (1) (In the above formula (1), M １ is at least one first element selected from the group consisting of Cs, Rb, K, Na, and Li, and A １ M is at least one organic cation selected from the group consisting of ammonium ions, formamidinium ions, guanidinium ions, imidazolium ions, pyridinium ions, pyrrolidinium ions, and protonated thiourea ions. ２ (where X is at least one second element selected from the group consisting of Ge, Sn, Pb, Sb, and Bi; X is an anion or ligand selected from the group consisting of chlorides, bromides, iodines, cyanides, thiocyanates, isothiocyanates, and sulfides; a is an integer from 1 to 4; b is an integer from 1 to 2; c is an integer from 3 to 9; d is from 0 to 1; e is from 0 to 1; and d + e = 1.)

19. The method for producing phosphor composite particles according to claim 12, wherein the film-like material consists of at least one inorganic substance selected from the group consisting of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and magnesium fluoride.

20. A method for manufacturing a wavelength conversion member, comprising forming a wavelength conversion sheet on the surface of a light-transmitting member using a wavelength conversion sheet composition comprising phosphor composite particles manufactured by the method of claim 11 or 12 and a second resin.

21. A method for manufacturing a wavelength conversion member, comprising: arranging a wavelength conversion sheet composition comprising phosphor composite particles manufactured by the method of claim 11 or 12 and a second resin on the surface of a first light-transmitting member; arranging a second light-transmitting member with the wavelength conversion sheet composition sandwiched between it and the first light-transmitting member; and joining the first light-transmitting member and the second light-transmitting member with a wavelength conversion sheet sandwiched between them.

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