Fluoride phosphor, method for producing thereof, and light emitting device

Abstract

This invention provides a fluoride phosphor that improves the reliability of a light-emitting device. The fluoride phosphor comprises fluoride particles and an oxide covering at least a portion of the surface of the fluoride particles. The oxide comprises at least one element selected from the group consisting of Si, Al, Ti, Zr, Sn, and Zn, and its content is 2% by mass or more and 30% by mass or less. The fluoride particles have the following composition: containing element M, an alkali metal, Mn, and F, comprising at least one element selected from the group consisting of Group 4, Group 13, and Group 14 elements; and when the mole number of the alkali metal is set to 2, the mole number of Mn is greater than 0 and less than 0.2, the mole number of element M is greater than 0.8 and less than 1, and the mole number of F is greater than 5 and less than 7.

Description

Technical Field

[0001] This invention relates to a fluoride phosphor, its manufacturing method, and a light-emitting device. Prior Technology

[0002] Light-emitting devices, which combine light-emitting elements and phosphors, are used in a wide range of fields, including lighting, automotive lighting, displays, and LCD backlights. For example, phosphors used in light-emitting devices for LCD backlights require high color purity, i.e., a narrow half-width at half-maximum (WHM) of the emission peak. Fluoride phosphors containing Mn are known as red-emitting phosphors with a narrow WHM of the emission peak.

[0003] For example, Japanese Patent Publication No. 2019-5259741 describes a method for reducing instability caused by the deterioration of manganese-doped red phosphors by coating manganese-doped red phosphors with aluminum oxide or the like. It also describes the manufacture of a light-emitting device comprising a fluorescent component including the coated manganese-doped red phosphor and a resin. Summary of the Invention

[0004] [The problem the invention aims to solve]

[0005] Regarding light-emitting devices comprising a fluorescent component including a fluoride phosphor and a resin, the reliability of the light-emitting device may decrease depending on the environment in which it is used. One aspect of the present invention aims to provide a fluoride phosphor, a method for manufacturing the same, and a light-emitting device that can further improve the reliability of the light-emitting device. [Technical means to solve the problem]

[0006] The first form is a fluoride phosphor comprising fluoride particles and an oxide covering at least a portion of the surface of the fluoride particles. The oxide comprises at least one element selected from the group consisting of Si, Al, Ti, Zr, Sn, and Zn, and its content is 2% by mass or more and 30% by mass or less relative to the fluoride phosphor. The fluoride particles have the following composition: containing element M, an alkali metal, Mn, and F, comprising at least one element selected from the group consisting of Group 4, Group 13, and Group 14 elements, and when the mole number of the alkali metal is set to 2, the mole number of Mn is greater than 0 and less than 0.2, the mole number of element M is greater than 0.8 and less than 1, and the mole number of F is greater than 5 and less than 7.

[0007] The second aspect is a method for manufacturing a fluoride phosphor, comprising: preparing fluoride particles; and contacting the prepared fluoride particles with a metal alkoxide comprising at least one of the elements selected from the group consisting of Si, Al, Ti, Zr, Sn, and Zn in a liquid medium, wherein an oxide derived from the metal alkoxide covers at least a portion of the surface of the fluoride particles in an amount of 2% by mass to 30% by mass relative to the fluoride phosphor. The fluoride particles have the following composition: containing at least one element M, an alkali metal, Mn, and F comprising the elements selected from the group consisting of Group 4, Group 13, and Group 14 elements, and when the mole number of the alkali metal is set to 2, the mole number of Mn is greater than 0 and less than 0.2, the mole number of element M is greater than 0.8 and less than 1, and the mole number of F is greater than 5 and less than 7.

[0008] The third aspect is a method for manufacturing a fluoride phosphor, comprising: preparing fluoride particles; in a liquid medium, contacting the prepared fluoride particles with at least one rare earth ion selected from the group consisting of La, Ce, Dy and Gd and phosphate ions to obtain fluoride particles with rare earth phosphate attached; and by contacting the fluoride particles with rare earth phosphate attached with at least one metal alkoxide selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn in a liquid medium, wherein the oxide derived from the metal alkoxide covers at least a portion of the surface of the fluoride particles with rare earth phosphate attached in an amount of 2% to 30% by mass relative to the fluoride phosphor. The fluoride particles have the following composition: containing at least one element M, an alkali metal, Mn, and F selected from the group consisting of elements selected from Group 4, Group 13, and Group 14, and when the mole number of the alkali metal is set to 2, the mole number of Mn is greater than 0 and less than 0.2, the mole number of element M is greater than 0.8 and less than 1, and the mole number of F is greater than 5 and less than 7.

[0009] The fourth form is a light-emitting device comprising: a fluorescent component including the fluoride phosphor and resin of the first form described above; and a light-emitting element having a peak emission wavelength in the wavelength range of 380 nm to 485 nm. [Effects of the Invention]

[0010] According to one aspect of the present invention, a fluoride phosphor, a method for manufacturing the same, and a light-emitting device can be provided that can further improve the reliability of the light-emitting device. Simple Explanation of the Diagram

[0011] Figure 1 is a schematic cross-sectional view of an example of a light-emitting device containing a fluoride phosphor. Figure 2 shows an example of a reflected electron image of a fluoride fluoride fluoride obtained using a scanning electron microscope (SEM). Figure 3 is an example of a cross-sectional SEM image of the fluoride phosphor of Example 6. Figure 4 is an example of a SEM image of the fluoride phosphor of Example 6. Figure 5 is an example of a cross-sectional SEM image of the fluoride phosphor of Example 8. Figure 6 is an example of a SEM image of the fluoride phosphor of Example 8. Implementation

[0012] The term "step" used in this specification includes not only independent steps, but also steps that cannot be clearly distinguished from other steps, as long as the desired purpose of the step can be achieved. Furthermore, when multiple substances corresponding to each component are present in the composition, unless otherwise specified, the content of each component in the composition refers to the total amount of such multiple substances present in the composition. Moreover, the upper and lower limits of the numerical ranges described in this specification can be arbitrarily selected as numerical ranges and combined with them. In this specification, the relationship between color names and chromaticity coordinates, and the relationship between the wavelength range of light and the color name of monochromatic light, etc., are in accordance with JIS Z8110. The half-width at half-maximum (FWHM) of a phosphor refers to the wavelength width (FWHM) of the emission spectrum of a phosphor, where the emission intensity is 50% of the maximum emission intensity. The median diameter of a phosphor is the volume-based diameter, referring to the particle size corresponding to the cumulative 50% of the volume from the smallest diameter side in a volume-based particle size distribution. The particle size distribution of the phosphor is determined by laser diffraction using a laser diffraction particle size distribution measuring device. Hereinafter, embodiments of the present invention will be described in detail. However, the embodiments shown below illustrate fluoride phosphors, their manufacturing methods, and light-emitting devices used to embody the technical concept of the present invention; the present invention is not limited to the fluoride phosphors, their manufacturing methods, and light-emitting devices shown below.

[0013] Fluoride phosphors The fluoride phosphor may have fluoride particles and an oxide covering at least a portion of the surface of the fluoride particles. The oxide comprises at least one element selected from the group consisting of silicon (Si), aluminum (Al), titanium (Ti), zirconium (Zr), tin (Sn), and zinc (Zn), and its content is 2% by mass to 30% by mass relative to the fluoride phosphor. The fluoride particles have the following composition: containing at least one element M selected from the group consisting of elements selected from Group 4, Group 13, and Group 14, an alkali metal, Mn, and F, and when the mole number of the alkali metal is set to 2, the mole number of Mn is greater than 0 and less than 0.2, the mole number of element M is greater than 0.8 and less than 1, and the mole number of F is greater than 5 and less than 7.

[0014] By covering at least a portion of the surface of fluoride particles with a specific composition with a prescribed amount of a specific oxide, for example, moisture resistance is improved. This enhances the reliability of light-emitting devices comprising fluorescent components including fluoride phosphors and resins. For example, the reduction in the mass of the fluorescent component under high temperature or high humidity conditions is suppressed. It is believed that the reduction in the mass of the fluorescent component is primarily due to a reduction in the amount of resin. It is believed that under high temperature or high humidity conditions, the fluoride particles come into direct contact with the resin, resulting in a reaction that causes the partial breakage of interatomic bonds in the resin, leading to the dispersion of decomposition products. It is believed that by covering the fluoride particles with a prescribed amount of an oxide considered to have higher chemical stability than the fluoride particles, direct contact between the resin and the fluoride particles is suppressed, their reaction is inhibited, and the amount of resin is maintained. It is believed that since the resin also functions as a protective component for the phosphor, the reduction in the amount of resin makes it more susceptible to the effects of an external environment containing moisture, thereby accelerating the degradation of the phosphor. Furthermore, due to the reduction in resin content, the shape of the light-emitting surface of the fluorescent component in the light-emitting device, as shown in Figure 1, becomes deformed, thereby increasing the possibility of total internal reflection of light from inside the light-emitting device. Therefore, it is believed that less light is extracted to the outside of the light-emitting device, resulting in a decrease in the luminous flux of the light-emitting device.

[0015] The fluoride particles constituting a fluoride fluorophore need to contain at least a fluorescent substance activated by Mn, or may contain only a fluorescent substance activated by Mn. Regarding the composition of the fluoride particles, when the mole number of the alkali metal is set to 2, the mole number of Mn may exceed 0 but not reach 0.2, preferably 0.01 to 0.12. Furthermore, regarding the composition of the fluoride particles, when the mole number of the alkali metal is set to 2, the mole number of element M may exceed 0.8 but not reach 1, preferably 0.88 to 0.99. Regarding the composition of the fluoride particles, when the mole number of the alkali metal is set to 2, the mole number of F may exceed 5 but not reach 7, preferably 5.9 to 6.1. The composition of the fluoride particles can be determined, for example, by inductively coupled plasma (ICP) emission spectroscopy.

[0016] The alkali metal in the composition of the fluoride particles may include at least one element selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs). Furthermore, the alkali metal may include at least potassium (K), and may also include at least one element selected from the group consisting of lithium (Li), sodium (Na), rubidium (Rb), and cesium (Cs). The ratio of the mole number of K to the total mole number of the alkali metal in the composition may, for example, be 0.90 or more, preferably 0.95 or more, or 0.97 or more. The upper limit of the mole number ratio of K may, for example, be 1 or less than 0.995. In the composition of the fluoride particles, a portion of the alkali metal may be substituted with ammonium ions (NH₄⁺). When a portion of the alkali metal is replaced by ammonium ions, the ratio of the mole number of ammonium ions to the total mole number of the alkali metal in the composition may, for example, be 0.10 or less, preferably 0.05 or less, or 0.03 or less. The lower limit of the ratio of the mole number of ammonium ions may, for example, exceed 0, and preferably be 0.005 or more.

[0017] Element M in the composition of the fluoride particles includes at least one selected from the group consisting of Group 4 elements, Group 13 elements, and Group 14 elements. As Group 4 elements, examples include titanium (Ti), zirconium (Zr), hafnium (Hf), etc., and at least one selected from the group consisting of these can be included. As Group 13 elements, examples include boron (B), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), etc., and at least one selected from the group consisting of these can be included. As Group 14 elements, examples include carbon (C), silicon (Si), germanium (Ge), tin (Sn), etc., and at least one selected from the group consisting of these can be included. Element M may at least include at least one of the Group 14 elements, preferably may at least include at least one of Si and Ge, more preferably may at least include Si. Also, element M may at least include at least one of the Group 13 elements and at least one of the Group 14 elements, preferably may at least include at least one of Al, Si, and Ge, more preferably may at least include Al and Si.

[0018] The first composition, which is one form of the composition of the fluoride particles, may include at least one selected from the group consisting of Group 4 elements and Group 14 elements as element M, preferably may include at least one selected from the group consisting of Group 14 elements, more preferably may include at least one of Si and Ge, and even more preferably may at least include Si. Also, in the first composition of the fluoride particles, with respect to the molar number 2 of the alkali metal, the total molar number of Si, Ge, and Mn may be 0.9 or more and 1.1 or less, preferably may be 0.95 or more and 1.05 or less, or 0.97 or more and 1.03 or less.

[0019] The first composition of the fluoride particles may be the composition represented by the following formula (1). A 1 c[M 1 1-bMn bF d] (1)

[0020] In formula (1), A 1 may include at least one selected from the group consisting of Li, Na, K, Rb, and Cs. M 1 at least includes at least one of Si and Ge, and may further include at least one element selected from the group consisting of Group 4 elements and Group 14 elements. Mn may be a tetravalent Mn ion. b satisfies 0 < b < 0.2, c is the absolute value of the charge of the [M 2 1-bMn bF d] ion, and d satisfies 5 < d < 7.

[0021] In formula (1), A1 contains at least K, and may further contain at least one selected from the group consisting of Li, Na, Rb, and Cs. Furthermore, a portion of A1 may be substituted with ammonium ions (NH4+). When a portion of A1 is substituted with ammonium ions, the ratio of the number of moles of ammonium ions to the total number of moles of A1 in the composition may, for example, be 0.10 or less, preferably 0.05 or less, or 0.03 or less. The lower limit of the ratio of the number of moles of ammonium ions may, for example, exceed 0, and preferably exceed 0.005.

[0022] In formula (1), b is preferably 0.005 to 0.15, 0.01 to 0.12, or 0.015 to 0.1. c can be, for example, 1.8 to 2.2, preferably 1.9 to 2.1, or 1.95 to 2.05. d is preferably 5.5 to 6.5, 5.9 to 6.1, 5.92 to 6.05, or 5.95 to 6.025.

[0023] Furthermore, the fluoride particles of the first composition may have the first theoretical composition represented by the following formula (1a). A 1 2M 1F 6:Mn (1a)

[0024] In formula (1a), A1 may include at least one element selected from the group consisting of Li, Na, K, Rb and Cs. M1 may include at least one element selected from Si and Ge, and may further include at least one element selected from the group consisting of Group 4 and Group 14 elements. Mn may be a tetravalent Mn ion.

[0025] The second composition, as one of the components of the fluoride particles, may include at least one element M selected from the group consisting of elements from Group 4 and Group 14, and at least one element from Group 13. Preferably, it may include at least one element selected from the group consisting of elements from Group 14, and at least one element from Group 13. More preferably, it may include at least Si and Al. Furthermore, in the second composition of the fluoride particles, the total molar number of Si, Al, and Mn relative to the alkali metal molar number 2 may be 0.9 or more and 1.1 or less, preferably 0.95 or more and 1.05 or less, or 0.97 or more and 1.03 or less. Moreover, in the second composition of the fluoride particles, the molar number of Al relative to the alkali metal molar number 2 may exceed 0 and be less than 0.1, preferably exceeding 0 and being less than 0.03, 0.002 or more and 0.02 or less, or 0.003 or more and 0.015 or less.

[0026] The second composition of the fluoride particles may be the composition represented by the following formula (2). A 2 f[M 2 1-eMn eF g] (2)

[0027] In formula (2), A 2 contains at least K and may further contain at least one selected from the group consisting of Li, Na, Rb, and Cs. M 2 contains at least Si and Al and may further contain at least one element selected from the group consisting of Group 4 elements, Group 13 elements, and Group 14 elements. Mn may be a tetravalent Mn ion. e satisfies 0 < e < 0.2, f is the absolute value of the charge of the [M 2 1-eMn eF g] ion, and g satisfies 5 < g < 7.

[0028] A part of A 2 in formula (2) may be replaced by an ammonium ion (NH 4 +). When a part of A 2 is replaced by an ammonium ion, the molar ratio of the ammonium ion to the total molar number of A 2 in the composition may be, for example, 0.10 or less, preferably 0.05 or less, or 0.03 or less. The lower limit of the molar ratio of the ammonium ion may exceed 0, and preferably may be 0.005 or more.

[0029] In formula (2), e is preferably 0.005 or more and 0.15 or less, 0.01 or more and 0.12 or less, or 0.015 or more and 0.1 or less. f may be, for example, 1.8 or more and 2.2 or less, preferably 1.9 or more and 2.1 or less, or 1.95 or more and 2.05 or less. g is preferably 5.5 or more and 6.5 or less, 5.9 or more and 6.1 or less, 5.92 or more and 6.05 or less, or 5.95 or more and 6.025 or less.

[0030] Furthermore, the fluoride particles of the second composition may have a second theoretical composition represented by the following formula (2a). A 2 2Si 1-pAl pF 6-p:Mn (2a)

[0031] In formula (2a), A 2 contains at least K and may further contain at least one selected from the group consisting of Li, Na, Rb, and Cs. p satisfies 0 < p < 1. Mn may be a tetravalent Mn ion.

[0032] Fluoride particles containing the second component may have irregularities, grooves, etc., on their surface. The surface condition of the particles can be evaluated, for example, by measuring the angle of repose of the powder containing the fluoride particles. The angle of repose of the powder containing the fluoride particles containing the second component may be, for example, 70° or less, preferably 65° or less, or 60° or less. The lower limit of the angle of repose is, for example, 30° or more. The angle of repose is measured, for example, by an injection method.

[0033] By creating irregularities or grooves on the surface of the fluoride particles having the second component, for example, when covering the fluoride particles with a specified amount of a specific oxide, the contact area between the fluoride particles and the oxide increases, thus achieving a strong bond between the fluoride particles and the oxide. This allows the fluoride particles to be coated with an oxide film that is not easily peeled off by external forces. Furthermore, in the step of covering the fluoride particles with a specified amount of a specific oxide, even if a relatively small amount of oxide raw material is used, it is possible to cover the fluoride particles with a specified amount of oxide. Similarly, when rare earth phosphates are coated on the surface of fluoride particles, or when rare earth phosphates are coated on fluoride particles through oxide media, by creating irregularities or grooves on the surface of the fluoride phosphor, the contact area between the fluoride particles and the rare earth phosphates increases when a specific amount of rare earth phosphates is used to coat the fluoride particles. Therefore, the bonding between the fluoride particles and the rare earth phosphates becomes stronger, resulting in a rare earth phosphate film that is not easily peeled off by external forces during the manufacture of the light-emitting device. Furthermore, in the step of coating fluoride particles with a specific amount of rare earth phosphates, even using a relatively small amount of rare earth phosphate raw material, it is possible to coat the fluoride particles with a specified amount of rare earth phosphates.

[0034] Regarding the median diameter of the fluoride particles based on volume, for example, from the viewpoint of improving brightness, it can be 5 μm to 90 μm, preferably 10 μm to 70 μm, or 15 μm to 50 μm. As for the particle size distribution of the fluoride particles, for example, from the viewpoint of improving brightness, it can represent a single-peak particle size distribution, preferably a single-peak particle size distribution with a narrow distribution width.

[0035] The fluoride phosphor may have an oxide covering at least a portion of the surface of the fluoride particles. The oxide may cover the surface of the fluoride particles in a film-like form, or it may be disposed as an oxide layer on the surface of the fluoride particles. Furthermore, the oxide film covering the surface of the fluoride particles is not limited to a completely crack-free state; cracks may exist in a portion of the oxide film covering the surface of the fluoride particles, provided that the desired effect of the invention is achieved. Preferably, the oxide film covering the surface of the fluoride particles completely covers the entire surface of the fluoride particles, but even if a portion of the oxide film is damaged, a portion of the surface of the fluoride particles may be exposed, provided that the desired effect of the invention is achieved. The ratio of fluoride particles covered by oxide in the fluoride phosphor may be, for example, 50% or more, preferably 80% or more, or 90% or more. The ratio of fluoride particles covered by oxide is calculated as the ratio of the area covered by oxide to the surface area of ​​the fluoride particles.

[0036] The oxide may contain at least one element selected from the group consisting of Si, Al, Ti, Zr, Sn, and Zn. That is, the oxide may contain at least one element selected from the group consisting of silicon oxide (e.g., SiOx, where x is 1 to 2, preferably 1.5 to 2, or approximately 2), aluminum oxide (e.g., Al₂O₃), titanium oxide (e.g., TiO₂), zirconium oxide (e.g., ZrO₂), tin oxide (e.g., SnO, SnO₂, etc.), and zinc oxide (e.g., ZnO), and may also contain at least silicon oxide. The oxide may contain only one element or may contain two or more elements.

[0037] The oxide content in the fluoride phosphor can be between 2% and 30% by mass, preferably between 5% and 20% by mass, or between 8% and 15% by mass. Regarding the oxide content in the fluoride phosphor, for example, when the oxide is silicon oxide, the amount of each constituent element in the oxide-covered fluoride particles and the fluoride particles without oxides is analyzed using inductively coupled plasma (ICP) emission spectroscopy. The molar ratio of each constituent element is calculated with the molar number of alkali metals being 2. The difference in the molar ratio of silicon before and after oxide coverage is converted into the mass of silicon oxide (e.g., SiO₂), and the mass of the oxide-covered fluoride particles (fluoride phosphor) is set to 100% by mass to calculate the silicon oxide (e.g., SiO₂) content. By keeping the oxide content within the above range, the reliability of the light-emitting device can be further improved.

[0038] In fluoride phosphors, fluoride particles can also be covered by an oxide layer. The average thickness of the oxide layer covering the fluoride particles can be, for example, 0.1 μm to 1.8 μm, preferably 0.15 μm to 1.0 μm, or 0.20 μm to 0.8 μm. The average thickness of the oxide layer in the fluoride phosphor is, for example, the measured average thickness obtained by taking the arithmetic mean of the thicknesses of multiple layers identified as oxide layers in a cross-sectional image of the fluoride phosphor. Furthermore, the average thickness of the oxide layer in the fluoride phosphor can be the theoretical thickness calculated based on the Kα ray intensity ratio of element F. The theoretical thickness can be calculated using the database of CXRO (The Center for X-Ray Optics), based on the ratio of the peak intensity of Kα rays from fluoride particles covered by oxide to the peak intensity of Kα rays from fluoride particles not covered by oxide. The theoretical thickness is calculated as an average value obtained by averaging the presence of defects such as cracks and gaps in the oxide layer.

[0039] In fluoride phosphors, since fluoride particles are covered by oxides, the peak intensity of characteristic X-rays from the fluoride particles decreases depending on the amount of oxide covering the fluoride particles. Therefore, in fluoride phosphors, the oxide coating state can be assessed by evaluating the peak intensity of characteristic X-rays from the fluoride particles. Specifically, in X-ray fluorescence (XRF) elemental analysis, the ratio of the peak intensity of Kα rays of element F in the fluoride phosphor to the peak intensity of Kα rays of element F in the fluoride particles can be, for example, 80% or less, preferably 70% or less, or 60% or less. The lower limit of the peak intensity ratio can be, for example, 20% or more. By keeping the ratio of the peak intensity of Kα rays of element F in the fluoride phosphor within the above range, the reliability of the light-emitting device can be further effectively improved.

[0040] In fluoride phosphors, rare earth phosphates can also be deposited on the surface of fluoride particles, thereby allowing the oxide to intersect and cover the fluoride particles with rare earth phosphates. This tends to further improve the resistance of the fluoride phosphor to damp heat. Furthermore, it tends to improve the adhesion of the oxide to the fluoride particles and further enhance the coating properties of the oxide. The rare earth phosphates deposited on the surface of the fluoride particles can act as particles attached to the surface of the fluoride particles, or as films or layers coating the surface of the fluoride particles. Preferably, they can act as particles attached to the surface of the fluoride particles.

[0041] Rare earth phosphates may contain at least one rare earth element selected from the group consisting of lanthanum (La), cerium (Ce), dysprosium (Dy) and thorium (Gd), preferably containing at least lanthanum.

[0042] The content of rare earth phosphates in fluorinated phosphors, in terms of the content of rare earth elements, can be, for example, 0.1% by mass or more but less than 20% by mass, preferably 0.2% by mass or more but less than 15% by mass, or 0.3% by mass or more but less than 10% by mass.

[0043] The surface of fluorinated phosphors can be treated with a coupling agent. Specifically, a surface treatment layer containing functional groups from the coupling agent can be deposited on the surface of the fluorinated phosphor. By depositing a surface treatment layer on the surface of the fluorinated phosphor, for example, the moisture resistance of the fluorinated phosphor is further improved.

[0044] As a functional group derived from the coupling agent, examples include silyl groups having an aliphatic group having 1 to 20 carbon atoms, and preferably silyl groups having an aliphatic group having 6 to 12 carbon atoms. The functional group derived from the coupling agent may be used alone or in combination of two or more.

[0045] Examples of coupling agents include silane coupling agents, titanium coupling agents, and aluminum coupling agents. Examples of silane coupling agents include, for example, alkyltrialkoxysilanes such as methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, and decyltriethoxysilane; aryltrialkoxysilanes such as phenyltrimethoxysilane and styryltrimethoxysilane; vinyltrimethoxysilanes such as vinyltrialkoxysilane; aminoalkyltrialkoxysilanes such as 3-aminopropyltriethoxysilane; and glycidoxyalkyltrialkoxysilanes such as 3-glycidoxypropyltrimethoxysilane. At least one of these can be selected from the group consisting of these. As a coupling agent, silane coupling agents are preferred due to their relatively easy availability.

[0046] In one embodiment, the fluoride phosphor may comprise fluoride particles and at least a portion of a rare-earth phosphate disposed on the surface of the fluoride particles. Furthermore, the fluoride phosphor formed by disposing of rare-earth phosphate on at least a portion of the surface of the fluoride particles may have a surface treatment layer comprising functional groups derived from a coupling agent disposed on its surface. The placement of rare-earth phosphate on the surface of the fluoride particles, for example, enhances the moisture resistance of the fluoride phosphor. This improves the reliability of the light-emitting device having a fluorescent component comprising a fluoride phosphor and a resin. Furthermore, for example, the reduction in the mass of the fluorescent component under high temperature or high humidity environments is suppressed. Furthermore, by applying a surface treatment layer containing functional groups derived from a coupling agent to the surface of a fluoride phosphor formed by configuring rare-earth phosphates on at least a portion of the surface of fluoride particles, the interfacial energy between the surface-treated fluoride phosphor and sealing resins such as silicone resin is reduced. Therefore, the fluoride phosphor becomes easier to mix and disperse uniformly in the sealing resin. Furthermore, when this mixture is injected into the package of a light-emitting device and allowed to stand, the fluoride phosphor can be densely and uniformly deposited onto the light-emitting element (e.g., an LED (Light Emitting Diode) chip). Therefore, the temperature of the fluoride phosphor can be kept low when driving the light-emitting device, resulting in a light-emitting device with higher luminous efficiency and higher reliability.

[0047] Regarding the median diameter of the fluoride phosphor based on volume, from the viewpoint of improving brightness, it can be 10 μm to 90 μm, preferably 15 μm to 70 μm, or 20 μm to 50 μm. Regarding the particle size distribution of the fluoride phosphor, from the viewpoint of improving brightness, it can represent a single-peaked particle size distribution, preferably a single-peaked particle size distribution with a narrow distribution width.

[0048] Fluoride fluoresces, for example, are fluoresces activated by tetravalent manganese ions, absorbing short-wavelength visible light and emitting red light. The excitation light can be primarily in the blue region, with a peak wavelength, for example, between 380 nm and 485 nm. The emission peak wavelength of the fluoride fluorescein's emission spectrum can, for example, be between 610 nm and 650 nm. The half-width at half-maximum (FWHM) of the fluoride fluorescein's emission spectrum can, for example, be less than 10 nm.

[0049] When the fluoride particles constituting the fluoride phosphor have a second component, the fluoride phosphor may have irregularities, grooves, etc., on its particle surface. The angle of repose of the powder containing the fluoride phosphor may be, for example, 70° or less, preferably 65° or less, or 60° or less, and the aforementioned fluoride phosphor contains fluoride particles having the second component. The lower limit of the angle of repose is, for example, 30° or more. The angle of repose is measured, for example, by an injection method.

[0050] Fluoride phosphors obtained by coating fluoride particles having the second composition with at least one of oxides and rare earth phosphates still have irregularities and grooves on their surface after coating. This irregularity or grooves on the surface of the fluoride phosphor reduces the contact area between the fluoride phosphor particles, thus suppressing particle aggregation. Therefore, when manufacturing a light-emitting device, the fluoride phosphor particles can be more uniformly dispersed in the resin composition. Furthermore, for example, when using a dispensing device in manufacturing a light-emitting device, it is less likely for fluoride phosphors to become clogged in the dispensing needle. Moreover, a light-emitting device with less aggregation of fluoride phosphor particles and less color uniformity can be obtained.

[0051] Method for manufacturing fluoride phosphors A first embodiment of the method for manufacturing a fluoride phosphor (hereinafter also referred to as the first manufacturing method) includes: a preparation step, which involves preparing fluoride particles; and a synthesis step, which involves contacting the prepared fluoride particles with a metal alkoxide selected from the group consisting of Si, Al, Ti, Zr, Sn, and Zn in a liquid medium, and covering the fluoride particles with an oxide from the metal alkoxide. In the first manufacturing method, the amount of oxide coating relative to the fluoride phosphor can be 2% by mass or more and 30% by mass or less. Furthermore, the prepared fluoride particles have the following composition: containing at least one element M selected from the group consisting of Group 4 elements, Group 13 elements, and Group 14 elements, an alkali metal, Mn, and F, and when the total mole number of the above-mentioned alkali metal is set to 2, the mole number of Mn is greater than 0 and less than 0.2, the mole number of element M is greater than 0.8 and less than 1, and the mole number of F is greater than 5 and less than 7.

[0052] By contacting fluoride particles with a specific composition with metal alkoxides in a liquid medium, fluoride phosphors in which at least a portion of the surface of the fluoride particles is covered with oxides derived from metal alkoxides can be efficiently manufactured. This leads to improved reliability in light-emitting devices comprising a fluorescent component including the obtained fluoride phosphor and a resin, for example, in high-temperature environments.

[0053] In the preparation step, fluoride particles with a specific composition are prepared. This preparation step can be done by purchasing fluoride particles or by manufacturing the required fluoride particles. Furthermore, the details of the prepared fluoride particles are as described above.

[0054] Fluoride particles can be manufactured, for example, as follows. When the fluoride particles have a first composition, they can be manufactured, for example, by a manufacturing method that includes the step of mixing solution a and solution b, wherein solution a contains at least a first fluoride ion containing tetravalent manganese, a second fluoride ion containing at least one element selected from the group consisting of elements of group 4 and group 14 and fluoride, and hydrogen fluoride, and solution b contains at least an alkali metal containing at least potassium and hydrogen fluoride.

[0055] Alternatively, it can be manufactured, for example, by a manufacturing method including the step of mixing the first solution with the second and third solutions, wherein the first solution contains at least a first fluoride ion containing tetravalent manganese and hydrogen fluoride, the second solution contains at least an alkali metal containing potassium and hydrogen fluoride, and the third solution contains at least one element selected from the group consisting of Group 4 and Group 14 elements and a second fluoride ion containing fluoride.

[0056] Furthermore, when the fluoride particles have a second composition, a method for manufacturing fluoride particles having the second composition can be, for example, by a manufacturing method comprising: preparing fluoride particles having a first composition; preparing fluoride particles comprising Al, alkali metals, and F; and a first heat treatment step, wherein the mixture comprising the fluoride particles having the first composition and the fluoride particles having the first composition is subjected to a first heat treatment at a first heat treatment temperature of 600°C to 780°C in an inert gas atmosphere. Here, in the composition of the fluoride particles comprising Al, alkali metals, and F, the ratio of the total moles of alkali metals to the moles of Al (1) can be 1 to 3, and the ratio of the moles of F can be 4 to 6. Alternatively, the ratio of the total moles of alkali metals to the moles of Al (1) can be 2 to 3, and the ratio of the moles of F can be 5 to 6.

[0057] The method for manufacturing fluoride phosphors may further include a second heat treatment step, wherein the second heat treatment step involves subjecting the first heat-treated material, which has undergone the first heat treatment, to a second heat treatment temperature of 400°C or higher to obtain a second heat-treated material.

[0058] Furthermore, the second heat treatment step can be performed only on the fluoride particles, or it can be performed on both the fluoride particles and the fluorine-containing substance. The fluorine-containing substance can be in a solid, liquid, or gaseous state at room temperature. Examples of solid or liquid fluorine-containing substances include NH₄F. Examples of gaseous fluorine-containing substances include F₂, CHF₃, CF₄, NH₄HF₂, HF, SiF₄, KrF₄, XeF₂, XeF₄, NF₃, etc., and at least one can be selected from the group consisting of these substances, preferably at least one selected from the group consisting of F₂ and HF. The second heat treatment temperature is preferably above 400°C, above 425°C, above 450°C, or above 480°C. The upper limit of the second heat treatment temperature may, for example, be less than 600°C, but preferably below 580°C, below 550°C, or below 520°C. The second heat treatment temperature may be lower than the first heat treatment temperature.

[0059] It is believed that the fluoride particles of the second composition synthesized by solid-state reaction in the first heat treatment step, by placing tetravalent Si ions, trivalent Al ions, and tetravalent Mn ions in the same position in the crystallization of the fluoride particles, become a state containing compounds with so-called mixed valences. Therefore, it is believed that pores exist at positions in the crystallization where the fluoride ions should exist in proportion to the ratio of tetravalent Si ions to trivalent Al ions and tetravalent Mn ions, in order to compensate for the insufficient charge of the overall mixed valence cations.

[0060] Here, for example, regarding fluoride particles synthesized by liquid-phase reaction as disclosed in Japanese Patent Application Publication No. 2010-254933, it is argued that at the positions where fluoride ions should be present in the crystals, a large number of hydroxide ions introduced from the solution into the crystals mix with fluoride ions, and these hydroxide ions become a cause of impaired stability of the fluoride particles. On the other hand, for fluoride particles of the second composition synthesized by heat treatment and solid-phase reaction, since a solution in which hydroxide ions may be present is not used, hydroxide ions that would impair the stability of the fluoride particles are not present.

[0061] Furthermore, in the fluoride particles of the second composition synthesized by solid-state reaction in the first heat treatment step, Mn ions with different valences may sometimes be mixed in during the crystallization process or on the crystal surface of the fluoride particles. When Mn ions with different valences are mixed in the fluoride particles, by heat treatment under conditions of contact with fluorine-containing substances, the valence of the Mn ions can be reduced to a tetravalent state, thereby improving the luminescence efficiency of the fluoride particles.

[0062] In the synthesis step, the prepared fluoride particles are contacted in a liquid medium with a metal alkoxide comprising at least one of the following groups: Si, Al, Ti, Zr, Sn, and Zn. The fluoride particles are then coated with an oxide derived from the metal alkoxide to obtain a fluoride phosphor. Alternatively, by solvent decomposition of the metal alkoxide, an oxide derived from the metal alkoxide can be generated, thereby obtaining a fluoride phosphor comprising fluoride particles coated with the generated oxide.

[0063] The aliphatic group of the alkoxide constituting the metal alkoxide may have 1 to 6 carbon atoms, preferably 1 to 4 or 1 to 3. The metal alkoxide contains at least one element selected from the group consisting of Si, Al, Ti, Zr, Sn, and Zn, but may contain at least Si. The metal and aliphatic group contained in the metal alkoxide may each contain only one element, or may be combined to contain two or more elements.

[0064] Specific examples of metal alkoxides include: tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, trimethoxyaluminum, triethoxyaluminum, triisopropoxyaluminum, tetramethoxytitanium, tetraethoxytitanium, tetraisopropoxytitanium, tetramethoxyzirconium, tetraethoxyzirconium, tetraisopropoxyzirconium, tetraethoxytin, dimethoxyzinc, diethoxyzinc, etc., preferably at least one from the group consisting of these, more preferably at least one from the group consisting of tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane. The metal alkoxide used in the synthesis step may be a single type or a combination of two or more types.

[0065] Regarding the amount of metal alkoxides added in the synthesis step, relative to the total mass of the fluoride particles, the amount added, converted to oxides, can be, for example, 2% by mass or more and 30% by mass, preferably 5% by mass or more, or 8% by mass or more, and even more preferably 25% by mass or less, or 20% by mass or less. Furthermore, regarding the amount of metal alkoxides added in the synthesis step, relative to the total mass of the fluoride particles, the amount of metal alkoxides added can be, for example, 5% by mass or more and 110% by mass, preferably 15% by mass or more, or 25% by mass or more, and even more preferably 90% by mass or less, or 75% by mass or less.

[0066] The contact between fluoride particles and metal alkoxides is carried out in a liquid medium. Examples of liquid media include: water; alcohol solvents such as methanol, ethanol, and isopropanol; nitrile solvents such as acetonitrile; and hydrocarbon solvents such as hexane. The liquid medium may contain at least water and an alcohol solvent. When the liquid medium contains an alcohol solvent, the content of the alcohol solvent in the liquid medium may be, for example, 60% by mass or more, preferably 70% by mass or more. Furthermore, the content of water in the liquid medium may be, for example, 4% by mass or more and 40% by mass or less.

[0067] Furthermore, the liquid medium may also contain a pH adjuster. Examples of pH adjusters include alkaline substances such as ammonia, sodium hydroxide, and potassium hydroxide, and acidic substances such as hydrochloric acid, nitric acid, sulfuric acid, and acetic acid. When the liquid medium contains a pH adjuster, the pH value of the liquid medium can be, for example, between 1 and 6 under acidic conditions, preferably between 2 and 5. Under alkaline conditions, the pH value of the liquid medium can be between 8 and 12, preferably between 8 and 11.

[0068] The mass ratio of the liquid medium to the fluoride particles can be, for example, 100% to 1000% by mass, preferably 150% or more, or 180% or more, and even more preferably 600% or less, or 300% or less. If the mass ratio of the liquid medium is within the above range, it is often possible to more uniformly cover the fluoride particles with oxides.

[0069] Contact between fluoride particles and metal alkoxides can be achieved, for example, by adding the metal alkoxide to a suspension containing fluoride particles. Stirring may be performed as needed. Furthermore, the contact temperature between the fluoride particles and the metal alkoxide can be, for example, between 0°C and 70°C, preferably between 10°C and 40°C. The contact time can be, for example, between 1 hour and 12 hours. Moreover, the contact time also includes the time required for adding the metal alkoxide.

[0070] A second method for manufacturing fluoride phosphors (hereinafter also referred to as the second manufacturing method) includes: a preparation step, which prepares fluoride particles; an attachment step, which involves contacting the prepared fluoride particles with rare earth ions containing at least one lanthanide element selected from the group consisting of La, Ce, Dy, and Gd, and phosphate ions in a liquid medium to obtain fluoride particles with attached rare earth phosphates; and a synthesis step, which involves contacting the fluoride particles with attached rare earth phosphates with a solution containing a metal alkoxide selected from the group consisting of Si, Al, Ti, Zr, Sn, and Zn, and covering the fluoride particles with attached rare earth phosphates with an oxide derived from the metal alkoxide. In the second manufacturing method, the amount of oxide coating relative to the fluoride phosphor can be more than 2% by mass and less than 30% by mass. Furthermore, the prepared fluoride particles have the following composition: containing at least one element M, an alkali metal, Mn, and F selected from the group consisting of elements selected from Group 4, Group 13, and Group 14, and when the mole number of the aforementioned alkali metal is set to 2, the mole number of Mn is greater than 0 and less than 0.2, the mole number of element M is greater than 0.8 and less than 1, and the mole number of F is greater than 5 and less than 7.

[0071] In the second manufacturing method, after attaching rare earth phosphates to the surface of fluoride particles, the fluoride particles with attached rare earth phosphates are covered with oxides derived from metal alkoxides, thereby further improving the resistance of the fluoride phosphor to damp heat.

[0072] The preparation steps in the second manufacturing method are the same as those in the first manufacturing method. Furthermore, the synthesis steps in the second manufacturing method are the same as those in the first manufacturing method, except that rare earth phosphates are attached to the fluoride particles used in the synthesis step.

[0073] In the adhesion step, the prepared fluoride particles are brought into contact with rare earth ions and phosphate ions in a liquid medium. Thereby, rare earth phosphates adhere to the surface of the fluoride particles, thereby obtaining fluoride particles with attached rare earth phosphates. It is believed that by adhering the rare earth phosphates to the fluoride particles in a liquid medium, the rare earth phosphates will adhere more uniformly to, for example, the surface of the fluoride particles.

[0074] The liquid medium only needs to be able to dissolve phosphate ions and rare earth ions. Considering the ease of dissolution of these ions, it is preferable to contain at least water. The liquid medium may also contain reducing agents such as hydrogen peroxide, organic solvents, pH adjusters, etc., as needed. Examples of organic solvents that can be included in the liquid medium include alcohols such as ethanol and isopropanol. Examples of pH adjusters include alkaline compounds such as ammonia, sodium hydroxide, and potassium hydroxide; and acidic compounds such as hydrochloric acid, nitric acid, sulfuric acid, and acetic acid. When the liquid medium contains a pH adjuster, the pH of the liquid medium is, for example, 1 to 6, preferably 1.5 to 4. If it is above the lower limit of the above values, there is a tendency to obtain a sufficient amount of rare earth phosphates adsorbed; and if it is below the upper limit of the above values, there is a tendency to suppress the decrease in the luminescence properties of fluoride phosphors. When the liquid medium contains water, the water content in the liquid medium is, for example, 70% by mass or more, preferably 80% by mass or more, and more preferably 90% by mass or more.

[0075] The mass ratio of the liquid medium to the fluoride particles is, for example, 100% by mass or more, or 200% by mass or more, or, for example, 1000% by mass or less, or 800% by mass or less. If the mass ratio of the liquid medium is above or below the aforementioned lower limit, it is easier for rare earth phosphates to adhere more uniformly to the surface of the fluoride particles. If the mass ratio of the liquid medium is below the aforementioned upper limit, there is a tendency for the proportion of rare earth phosphates adhering to the fluoride particles to further increase.

[0076] The liquid medium preferably contains phosphate ions, and more preferably contains both water and phosphate ions. When the liquid medium contains phosphate ions, by mixing the prepared fluoride particles with the liquid medium, and then mixing it with a solution containing rare earth ions, the phosphate ions and rare earth ions can be brought into contact in the liquid medium containing the fluoride particles. When the liquid medium contains phosphate ions, the concentration of phosphate ions in the liquid medium is, for example, 0.05% by mass or more, preferably 0.1% by mass or more, and, for example, 5% by mass or less, preferably 3% by mass or less. If the concentration of phosphate ions in the liquid medium is above or below the aforementioned lower limit, the amount of liquid medium will not become excessive, the dissolution of components from the fluoride particles will be suppressed, and the characteristics of the fluoride phosphor will be well maintained. Furthermore, if it is below the aforementioned upper limit, the uniformity of the adhering material to the fluoride particles will be better.

[0077] Phosphate ions include orthophosphate ions, polyphosphate (metaphosphate) ions, phosphite ions, and hypophosphite ions. Polyphosphate ions include linear polyphosphate ions such as pyrophosphate ions and tripolyphosphate ions, and cyclic polyphosphate ions such as hexametaphosphate ions.

[0078] When the liquid medium contains phosphate ions, it can be prepared by dissolving the compound that will serve as the phosphate ion source in the liquid medium, or by mixing the solution containing the phosphate ion source with the liquid medium. Examples of phosphate ion sources include: phosphoric acid; metaphosphoric acid; alkali metal phosphates such as sodium phosphate and potassium phosphate; alkali metal hydrogen phosphates such as sodium hydrogen phosphate and potassium hydrogen phosphate; dihydrogen phosphates such as sodium dihydrogen phosphate and potassium dihydrogen phosphate; alkali metal hexametaphosphates such as sodium hexametaphosphate and potassium hexametaphosphate; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; and ammonium phosphates such as ammonium phosphate.

[0079] The liquid medium preferably contains a reducing agent, more preferably water and a reducing agent, and even more preferably water, phosphate ions, and a reducing agent. By including a reducing agent in the liquid medium, the precipitation of manganese dioxide and other substances originating from manganese contained in fluoride particles can be effectively suppressed. The reducing agent contained in the liquid medium only needs to be able to reduce, for example, tetravalent manganese ions dissolved from the fluoride into the liquid medium; examples include hydrogen peroxide, oxalic acid, and hydroxylamine hydrochloride. Among these, hydrogen peroxide is preferred in terms of not adversely affecting the fluoride because it decomposes into water.

[0080] When the liquid medium contains a reducing agent, it can be prepared by dissolving the compound that will become the reducing agent in the liquid medium, or by mixing a solution containing the reducing agent with the liquid medium. There is no particular limitation on the content of the reducing agent in the liquid medium, but for the reasons mentioned above, it is, for example, 0.1% by mass or more, preferably 0.3% by mass or more.

[0081] Rare earth elements that can become rare earth ions in contact with phosphate ions include, in addition to Sc and Y, lanthanide elements including La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. It is preferred to select at least one lanthanide element, and more preferably at least one element selected from the group consisting of La, Ce, Dy and Gd.

[0082] The contact between phosphate ions and rare earth ions in a liquid medium can be achieved, for example, by dissolving a compound that will serve as a rare earth ion source in a liquid medium containing phosphate ions, or by mixing a liquid medium containing phosphate ions with a solution containing rare earth ions. A solution containing rare earth ions can be prepared, for example, by dissolving a compound that will serve as a rare earth ion source in a solvent such as water. Compounds serving as rare earth ion sources can be, for example, metal salts containing rare earth elements. Examples of anions constituting metal salts include nitrate ions, sulfate ions, acetate ions, and chloride ions.

[0083] Contact between phosphate ions and rare earth ions in a liquid medium may include, for example, mixing a liquid medium containing phosphate ions, preferably further containing a reducing agent, with fluoride particles to obtain a fluorescent slurry; and mixing the fluorescent slurry with a solution containing rare earth ions.

[0084] The content of rare earth ions in the liquid medium for contacting phosphate ions and rare earth ions is, for example, 0.05% by mass or more, or 0.1% by mass or more, or, for example, 3% by mass or less, or 2% by mass or less. Furthermore, the content of rare earth ions in the liquid medium relative to the amount of fluoride particles is, for example, 0.2% by mass or more, or 0.5% by mass or more, or, for example, 30% by mass or less, or 20% by mass or less. If the concentration of rare earth ions is above or below the aforementioned lower limit, there is a tendency for the ratio of rare earth phosphates adhering to fluoride particles to further increase; if the concentration of rare earth ions is below the aforementioned upper limit, there is a tendency for rare earth phosphates to adhere more uniformly to the surface of fluoride particles.

[0085] The contact temperature between phosphate ions and rare earth ions forming rare earth phosphates is, for example, 10°C to 50°C, preferably 20°C to 35°C. The contact time is, for example, 1 minute to 1 hour, preferably 3 minutes to 30 minutes. The liquid medium can be stirred while the contact is being maintained.

[0086] A separation step can also be added after the attachment step. This separation step separates the fluoride particles with attached rare earth phosphates from the liquid medium. Separation can be carried out, for example, by solid-liquid separation methods such as filtration or centrifugation. The phosphor obtained by solid-liquid separation can also be washed or dried as needed.

[0087] The method for manufacturing fluoride phosphors may further include: a step of recovering the fluoride phosphor obtained in the synthesis step by solid-liquid separation after the synthesis step, and a step of drying the fluoride phosphor after solid-liquid separation.

[0088] The method for manufacturing fluoride phosphors may also include a surface treatment step, which involves treating the fluoride phosphor obtained in the synthesis step with a coupling agent. It may also include the following treatment: after coating the fluoride particles with an oxide derived from a metal alkoxide, a silane coupling treatment is then performed. In the surface treatment step, by contacting the fluoride phosphor with the coupling agent, a surface treatment layer containing functional groups derived from the coupling agent can be applied to the surface of the fluoride phosphor. This, for example, improves the moisture resistance of the fluoride phosphor.

[0089] Specific examples of the coupling agent used in the surface treatment step are as described above. Furthermore, the amount of coupling agent used in the surface treatment step, for example, relative to the mass of the fluoride phosphor, can be 0.5% by mass or more and 10% by mass or less, preferably 1% by mass or more and 5% by mass or less. The contact temperature between the fluoride phosphor and the coupling agent can, for example, be 0°C or more and 70°C or less, preferably 10°C or more and 40°C or less. The contact time between the fluoride phosphor and the coupling agent can, for example, be 1 minute or more and 10 hours or less, preferably 10 minutes or more and 1 hour or less.

[0090] Light-emitting device The light-emitting device includes: a fluorescent component comprising a first phosphor containing the aforementioned fluoride phosphor and a resin; and a light-emitting element having a peak emission wavelength in the wavelength range of 380 nm to 485 nm. The light-emitting device may also include other constituent components as needed.

[0091] An example of a light-emitting device will be described based on the figures. Figure 1 is a schematic cross-sectional view showing an example of a light-emitting device according to this embodiment. This light-emitting device is an example of a surface-mount type light-emitting device. The light-emitting device 100 includes: a light-emitting element 10 that emits light at short wavelengths of visible light (e.g., 380 nm or higher, 485 nm). The light has a peak emission wavelength in the range below nm; and a molded body 40 on which a light-emitting element 10 is disposed. The molded body 40 has a first conductive wire 20 and a second conductive wire 30, and is integrally molded by thermoplastic resin or thermosetting resin. The molded body 40 is formed with a recess having a bottom surface and a side surface, and the light-emitting element 10 is disposed on the bottom surface of the recess. The light-emitting element 10 has a pair of positive and negative electrodes, which are electrically connected via the first conductive wire 20, the second conductive wire 30 and a metal wire 60. The light-emitting element 10 is sealed by a fluorescent component 50. The fluorescent component 50 contains a phosphor 70, which includes a fluorinated phosphor that performs wavelength conversion on the light from the light-emitting element 10. The phosphor 70 may also include: a first phosphor, which includes the aforementioned fluorinated phosphor; and a second phosphor, which emits light with a peak emission wavelength in a wavelength range different from that of the fluorinated phosphor by excitation light from the light-emitting element 10.

[0092] Fluorescent components may include resin and phosphor. Examples of resins constituting fluorescent components include silicone resin, epoxy resin, modified silicone resin, modified epoxy resin, and acrylic resin. For example, the refractive index of silicone resin can be between 1.35 and 1.55, and more preferably between 1.38 and 1.43. Silicone resin with a refractive index within these ranges exhibits excellent light transmittance and is suitable for use as a resin constituting fluorescent components. Here, the refractive index of the silicone resin is the refractive index after curing and is measured according to JIS K7142:2008. In addition to resin and phosphor, fluorescent components may also include light-diffusing materials. By including light-diffusing materials, the directivity from the light-emitting element can be mitigated, and the viewing angle can be expanded. Examples of light-diffusing materials include silicon oxide, titanium oxide, zinc oxide, zirconium oxide, and aluminum oxide.

[0093] The light-emitting element emits light with a peak emission wavelength in the short wavelength region of visible light, specifically in the range of 380 nm to 485 nm. The light-emitting element can be an excitation source for exciting a fluoride phosphor. Preferably, the light-emitting element has a peak emission wavelength in the range of 380 nm to 480 nm, more preferably in the range of 410 nm to 480 nm, and even more preferably in the range of 430 nm to 480 nm. A semiconductor light-emitting element is preferably used as the excitation source. By using a semiconductor light-emitting element as the excitation source, a stable light-emitting device with high efficiency, high linearity of output relative to input, and resistance to mechanical shock can be obtained. For example, a semiconductor light-emitting element utilizing a nitride-based semiconductor can be used. The half-width at half-maximum (FWHM) of the emission peak in the emission spectrum of the light-emitting element is preferably, for example, 30 nm or less.

[0094] The light-emitting device includes a first phosphor containing a fluoride phosphor. Details of the fluoride phosphor included in the light-emitting device are as described above. The fluoride phosphor is, for example, included in a fluorescent component covering an excitation light source. In a light-emitting device where the excitation light source is covered by a fluorescent component containing a fluoride phosphor, a portion of the light emitted from the excitation light source is absorbed by the fluoride phosphor and emitted as red light. By using an excitation light source that emits light with a peak emission wavelength in the range of 380 nm to 485 nm, the emitted light can be utilized more effectively, the light loss emitted by the self-emissive device can be reduced, and a high-efficiency light-emitting device can be provided.

[0095] The light-emitting device preferably includes a first phosphor containing a fluoride phosphor, and further includes a second phosphor containing a phosphor other than the fluoride phosphor. The phosphor other than the fluoride phosphor only needs to absorb light from the light source and convert its wavelength to a different wavelength than that of the fluoride phosphor. The second phosphor can, for example, be included in the fluorescent component in the same way as the first phosphor.

[0096] The second phosphor may have an emission peak wavelength within a wavelength range of more than 495 nm and less than 590 nm, and preferably may be at least one selected from the group consisting of β-sialon phosphors, halosilicate phosphors, silicate phosphors, rare earth aluminate phosphors, perovskite-based luminescent materials, and nitride phosphors. The β-sialon phosphor may have a composition represented by, for example, the following formula (IIa). The halosilicate phosphor may have a composition represented by, for example, the following formula (IIb). The silicate phosphor may have a composition represented by, for example, the following formula (IIc). The rare earth aluminate phosphor may have a composition represented by the following formula (IId). The perovskite-based luminescent material may have a composition represented by, for example, the following formula (IIe). The nitride phosphor may have a composition represented by, for example, the following formula (IIf), (IIg), or (IIh). By making the fluorescent member contain a β-sialon phosphor or a perovskite-based luminescent material as the second phosphor other than the fluoride phosphor, when the light-emitting device is used as a light source for, for example, a backlight, a light-emitting device with a wider color reproducibility range can be manufactured. By making the fluorescent member contain a halosilicate phosphor, a silicate phosphor, a rare earth aluminate phosphor, or a nitride phosphor as the second phosphor other than the fluoride phosphor, when the light-emitting device is used as a light source for, for example, illumination, a light-emitting device with higher color rendering properties or higher luminous efficiency can be manufactured.

[0097] Si 6-tAl tO tN 8-t:Eu (IIa) (In formula (IIa), t is a number satisfying 0 < t ≤ 4.2) (Ca,Sr,Ba) 8MgSi 4O 16(F,Cl,Br) 2:Eu (IIb) (Ba,Sr,Ca,Mg) 2SiO 4:Eu (IIc) (Y,Lu,Gd,Tb) 3(Al,Ga) 5O 12:Ce (IId) CsPb(F,Cl,Br,I) 3(IIe) (La,Y,Gd) 3Si 6N 11:Ce (IIf) (Sr,Ca)LiAl 3N 4:Eu (IIg) (Ca,Sr)AlSiN 3:Eu (IIh)

[0098] In this specification, in formulas representing the composition of phosphors or luminescent materials, the use of commas (,) to separate multiple elements indicates that the composition contains at least one of those multiple elements. Furthermore, in formulas representing the composition of phosphors, the part before the colon (:) represents the parent crystal, and the part after the colon (:) represents the activating element.

[0099] The average particle size of the second phosphor can be, for example, 0.1 μm or more and 7 μm or less, preferably 0.2 μm or more or 0.5 μm or more. Furthermore, the average particle size is preferably 5 μm or less or 3 μm or less. The average particle size of the second phosphor is determined by the FSSS (Fisher Sub-sieve Size) method. The fluorescent component may contain only one type of second phosphor, or it may combine two or more types.

[0100] The fluorescent component may, in addition to the first phosphor, further include at least one type of quantum dot. The quantum dot can absorb light from a light source and convert its wavelength to a different wavelength than that of the first phosphor, or it can convert the wavelength to the same degree. Examples of quantum dots include: quantum dots with a perovskite structure comprising (Cs, FA, MA)(Pb, Sn)(Cl, Br, I)3 (where FA refers to amitrazine and MA refers to methylammonium); quantum dots with a chalcopyrite structure comprising (Ag, Cu, Au)(In, Ga)(S, Se, Te)2; semiconductor quantum dots such as (Cd, Zn)(Se, S); and InP-based semiconductor quantum dots, etc., and may include at least one type selected from the group consisting of these. Here, in the formula representing the composition of the quantum dot, the multiple elements or cations separated by commas (,) indicate that the composition contains at least one of these multiple elements or cations.

[0101] The present invention further includes the following aspects: the use of the fluoride phosphor in the manufacture of the light-emitting device; the use of the fluoride phosphor in the manufacture of the light-emitting device; the use of the fluoride particles in the manufacture of the fluoride phosphor; and the use of the fluoride particles in the manufacture of the fluoride phosphor. [Example]

[0102] The present invention will be described in more detail below with reference to embodiments, but the present invention is not limited to these embodiments.

[0103] Manufacturing Example 1 Using the above method, a phosphor, namely fluoride particle A1, with a Mn content of 1.5% by mass and having the first theoretical composition represented by K2SiF6:Mn (hereinafter sometimes simply referred to as "KSF"), is obtained.

[0104] Manufacturing Example 2 Using the above method, a phosphor, namely fluoride particle A2, with a Mn content of 1.5% by mass and having the second theoretical composition represented by K 2Si 0.99Al 0.01F 5.99:Mn (hereinafter sometimes simply referred to as "KSAF"), is obtained.

[0105] Manufacturing Example 3 15.0 g of 35% hydrogen peroxide solution and 735.0 g of pure water were added to 150.0 g of sodium phosphate aqueous solution (phosphate concentration: 2.4% by mass) and stirred at 400 rpm using a stirrer. At the same time as stirring at room temperature, 300 g of fluoride particles A1 manufactured in Manufacturing Example 1 were added to prepare a fluorescent slurry.

[0106] Subsequently, an aqueous solution of lanthanum nitrate (lanthanum concentration: 5.0% by mass), prepared by dissolving 23.4 g of lanthanum nitrate dihydrate in 156.6 g of pure water, was added dropwise to the fluorescent slurry over a period of approximately 1 minute. Stirring was stopped approximately 30 minutes after the addition was completed, and the mixture was allowed to stand. After removing the supernatant, it was thoroughly washed with washing water containing 1% by mass hydrogen peroxide. The obtained precipitate was subjected to solid-liquid separation, washed with ethanol, and dried at 90°C for 10 hours, thereby producing fluoride particles A3 of Preparation Example 3 with lanthanum phosphate deposited on their surface.

[0107] Manufacturing Example 4 In addition to using the fluoride particles A2 manufactured in Manufacturing Example 2, fluoride particles A4 of Manufacturing Example 4, which have lanthanum phosphate deposited on their surface, are manufactured using the same method as in Manufacturing Example 3.

[0108] Manufacturing Example 5 Using the above method, a fluoride particle A5 was obtained, which has a Mn content of 1.0% by mass and has the second theoretical composition represented by K 2Si 0.99Al 0.01F 5.99:Mn.

[0109] Manufacturing Example 6 In addition to using the fluoride particles A5 manufactured in Manufacturing Example 5, the fluoride particles A6 of Manufacturing Example 6, which have lanthanum phosphate deposited on their surface, are manufactured using the same method as in Manufacturing Example 3.

[0110] Manufacturing Example 7 After obtaining a phosphor with a Mn content of 1.2% by mass and a second theoretical composition represented by K 2Si 0.99Al 0.01F 5.99:Mn by the above method, fluoride particles A7 of Manufacturing Example 7, which have lanthanum phosphate disposed on their surface, are produced by the same method as Manufacturing Example 3.

[0111] Example 1 300 g of fluoride particles A1 produced in Example 1 were weighed and added to a solution prepared by mixing 540 ml of ethanol, 130.2 ml of ammonia solution containing 16.5% by mass of ammonia, and 60 ml of pure water. The solution was stirred at 400 rpm with a stirrer while maintaining the temperature at room temperature to prepare a reaction mother liquor. 32.1 g of tetraethoxysilane (TEOS:Si(OC2H5)4) was weighed and added dropwise to the stirred reaction mother liquor over approximately 3 hours. Stirring was then continued for 1 hour, followed by the addition of 10 g of 35% by mass hydrogen peroxide (H2O2), after which stirring was stopped. The resulting precipitate was subjected to solid-liquid separation, washed with ethanol, and dried at 105°C for 10 hours to prepare the fluoride phosphor E1 of Example 1, which was coated with silicon dioxide (SiO2). Furthermore, the amount of tetraethoxysilane added is approximately 3 by mass relative to the fluoride particles, converted to silicon dioxide.

[0112] Example 2 Except that the amount of tetraethoxysilane added was set to 107.1 g, the fluoride phosphor E2 of Example 2 was prepared using the same method as in Example 1. The amount of tetraethoxysilane added relative to the fluoride particles was approximately 10% by mass in silica conversion.

[0113] Figure 2 shows a reflected electron image obtained by observing the fluoride phosphor obtained in Example 2 using a scanning electron microscope. In Figure 2, the relatively abundant gray areas observed correspond to the silicon dioxide film, while the slightly darker gray areas that appear to be a mesh correspond to a portion of the surface of the fluoride particles. As shown in Figure 2, in the fluoride phosphor, most of the surface of the fluoride particles is covered by silicon dioxide. It can be seen that the morphology of the silicon dioxide covering the fluoride particles is not particles but a continuous film. It is believed that by covering the fluoride particles with silicon dioxide in a film form, direct contact between the fluoride particles and the resin can be effectively suppressed. Furthermore, a portion of the silicon dioxide film has cracks (slightly darker gray areas). It is believed that when there are fewer of these cracks, direct contact between the fluoride particles and the resin can be suppressed more effectively.

[0114] Example 3 Except that the amount of tetraethoxysilane added was set to 214.2 g, the fluoride phosphor E3 of Example 3 was prepared using the same method as in Example 1. The amount of tetraethoxysilane added relative to the fluoride particles was approximately 20% by mass in silica conversion.

[0115] Example 4 Using the fluoride particles A2 manufactured in Manufacturing Example 2, the stirring speed was set to 500 rpm and the amount of tetraethoxysilane added was set to 107.1 g. Otherwise, the fluoride phosphor E4 of Example 4 was prepared in the same manner as in Example 1.

[0116] Example 5 Weigh 100 g of the fluoride particles A3 produced in Manufacturing Example 3 and add them to a solution prepared by mixing 180 ml of ethanol, 43.4 ml of ammonia water containing 16.5% by mass of ammonia, and 20 ml of pure water. Set the stirring speed of the stirring blade to 300 rpm and add 35.7 g of tetraethoxysilane dropwise over 6 hours. Otherwise, prepare the fluoride phosphor E5 of Example 5 by the same method as in Example 1.

[0117] Example 6 100 g of fluoride particles A3 produced in Example 3 were weighed and added to a solution prepared by mixing 139 ml of ethanol and 35.7 ml of pure water. The solution was stirred at 300 rpm with a stirrer while maintaining the liquid temperature at room temperature to prepare a reaction mother liquor. 35.7 g of tetraethoxysilane was weighed as solution A, and 42.9 g of ammonia water containing 16.5% by mass of ammonia was weighed as solution B. After about 3 hours, solutions A and B were added dropwise to the reaction mother liquor under stirring. The mixture was stirred for 1 hour, and then 10 g of 35% by mass hydrogen peroxide (H2O2) was added, after which stirring was stopped. The obtained precipitate was subjected to solid-liquid separation, washed with ethanol, and dried at 105°C for 10 hours to prepare the fluoride phosphor E6 of Example 6.

[0118] Example 7 First, 50 g of the fluoride phosphor E6 prepared in Example 6 was weighed. Then, 84.9 ml of ethanol, 5.8 ml of pure water, and decyltrimethoxysilane ((CH3O)3Si(CH2)9CH3) as a silane coupling agent were mixed and stirred for 30 minutes, then allowed to stand for at least 20 hours. The fluoride phosphor E6 prepared in Example 6 was then added to this solution, and the mixture was stirred at 200 rpm for 1 hour, after which stirring was stopped. The obtained precipitate was subjected to solid-liquid separation and dried at 105°C for 10 hours for silane coupling treatment to obtain the fluoride phosphor E7.

[0119] Example 8 Except for using the fluoride particles A4 manufactured in Example 4, the fluoride phosphor E8 of Example 8 was manufactured in the same manner as in Example 4.

[0120] Example 9 Except for the fluoride phosphor E8 prepared in Example 8, the fluoride phosphor E9 of Example 9 was prepared in the same manner as in Example 7.

[0121] Example 10 Using the fluoride particles A5 manufactured in Example 5, the stirring speed was set to 350 rpm and the dropping time of tetraethoxysilane was set to 6 hours. Otherwise, the fluoride phosphor E10 of Example 10 was prepared in the same manner as in Example 2.

[0122] Example 11 Except for using the fluoride particles A6 manufactured in Manufacturing Example 6, the fluoride phosphor E11 of Example 11 was manufactured in the same manner as in Example 10.

[0123] Example 12 Except for the fluoride phosphor E11 prepared in Example 11, the fluoride phosphor E12 of Example 12 was prepared in the same manner as in Example 7.

[0124] Example 13 Except that the amount of tetraethoxysilane added was set to 64.3 g, the fluoride phosphor E13 of Example 13 was obtained by the same method as in Example 10.

[0125] Example 14 Except that the amount of tetraethoxysilane added was set to 32.2 g, the fluorinated phosphor E14 of Example 14 was obtained by the same method as in Example 10.

[0126] Example 15 Except for using the fluoride particles A7 manufactured in Manufacturing Example 7, the fluoride phosphor was obtained by the same method as in Example 13. Except for using hexyltrimethoxysilane as a silane coupling agent, the obtained phosphor was subjected to silane coupling treatment by the same method as in Example 7, thereby obtaining the fluoride phosphor E15 of Example 15.

[0127] Example 16 Except that vinyltrimethoxysilane was used as a silane coupling agent, the fluoride phosphor E16 of Example 16 was obtained by the same method as in Example 15.

[0128] Example 17 Except for the use of 3-aminopropyltriethoxysilane as a silane coupling agent, the fluorinated phosphor E17 of Example 17 was obtained by the same method as in Example 15.

[0129] Example 18 Except for the use of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, the fluorinated phosphor E18 of Example 18 was obtained by the same method as in Example 15.

[0130] Reference Example 1 The fluoride particles A1 obtained in Manufacturing Example 1 were used as the fluoride phosphor C1 in Reference Example 1.

[0131] See Example 2 The fluoride particle A2 obtained in Manufacturing Example 2 is used as the fluoride phosphor C2 of Reference Example 2.

[0132] See Example 3 The fluoride particles A3 obtained in Manufacturing Example 3 were used as the fluoride phosphor C3 in Reference Example 3.

[0133] See Example 4 The fluoride particles A4 obtained in Manufacturing Example 4 are used as the fluoride phosphor C4 of Reference Example 4.

[0134] See Example 5 The fluoride particles A6 obtained in Manufacturing Example 6 were used as the fluoride phosphor C5 in Reference Example 5.

[0135] See Example 6 The fluoride particles A7 obtained in Manufacturing Example 7 were used as the fluoride phosphor C6 in Reference Example 6.

[0136] Evaluate (1) Silicon dioxide content For each fluoride phosphor obtained, compositional analysis was performed using ICP emission spectroscopy. The amount of silicon dioxide covering the fluoride particles was calculated based on the difference between the analytical Si concentration of the silicon dioxide-coated fluoride phosphor obtained in the examples and the analytical Si concentration of the fluoride phosphor in the reference examples. The content of silicon dioxide relative to the fluoride phosphor (SiO2 analytical value) was then determined. The results are shown in Tables 1, 2, 3, and 4.

[0137] (2) Fluorescence X-ray elemental analysis: XRF assessment For each fluoride phosphor obtained above, the peak intensity of the Kα ray of element F was determined using XRF (X-Ray Fluorescence Spectrometry) with an XRF apparatus (product name: ZSX PrimusII, manufactured by RIGAKU Co., Ltd.). The peak intensity ratio of the fluoride phosphors in Examples 1 to 3 was calculated relative to the peak intensity of the fluoride phosphor in Reference Example 1 when it was 100. Similarly, the peak intensity ratio of the fluoride phosphor in Example 4 was calculated relative to the peak intensity of the fluoride particles in Reference Example 2 when it was 100. Based on the obtained peak intensity ratios, the average thickness of the silicon dioxide film in the fluoride phosphors of each example was calculated using the database of CXRO (The Center for X-Ray Optics). The results are shown in Table 1.

[0138] (3) Scanning electron microscopy observation The fluoride phosphors obtained in Examples 6 and 8 were imaged using a scanning electron microscope (SEM). The SEM images are shown in Figures 4 and 6. Furthermore, arbitrary cross-sections of the fluoride phosphors of Examples 6 and 8 were observed using a scanning electron microscope (SEM) and image analysis was performed to measure the average thickness of the silicon dioxide film. Specifically, a plurality of fluoride phosphor particles were embedded in resin, and cross-sectional samples were prepared by ion milling to create a state in which the cross-sections of the fluoride phosphor particles could be observed using a scanning electron microscope. The cross-sectional SEM images are shown in Figures 3 and 5.

[0139] For the obtained cross-sectional SEM images, the thickness of the silicon dioxide film at five locations was measured for each fluoride phosphor particle. The measured average thickness was calculated as the arithmetic mean of the thicknesses at a total of 25 locations for the five particles. Here, the silicon dioxide film thickness refers to the thickness of the film visible on the SEM image, including portions of the film obliquely cut relative to the thickness direction. The results are shown in Table 2.

[0140] (4) Total Carbon (TC) For the fluoride phosphors obtained in Examples 7, 9, 12, and 15 to 18, and Reference Examples 3 and 4, total carbon (TC) analysis was performed using a total organic carbon analyzer (product name: TOC-L, manufactured by Shimadzu Corporation). The results are shown in Tables 2, 4, and 5.

[0141] (5) Lanthanum content For the fluoride phosphors obtained in Examples 5 to 9 and 11 to 18 and Reference Examples 3 to 6, the lanthanum content was analyzed using inductively coupled plasma emission spectrometry (ICP-AES) to determine the content relative to the fluoride particles (La analytical value). The results are shown in Tables 2 and 4.

[0142] (6) Manganese content For the fluoride phosphors obtained in Examples 10 to 18 and Reference Examples 1, 3, 5 and 6, the manganese content was analyzed using inductively coupled plasma emission spectrometry (ICP-AES) to determine the content (Mn analysis value) relative to the fluoride phosphor. The results are shown in Tables 3 and 4.

[0143] (7) Assessment of quality changes in the resin composition The effect of fluorinated phosphors on the mass change of resin compositions containing resin and fluorinated phosphors was evaluated as follows: A resin composition was prepared by mixing fluorinated phosphors at 33% by mass relative to silicone resin. Approximately 1 g of the obtained resin composition was weighed onto aluminum foil and allowed to harden. The difference between the mass of the hardened resin composition and the mass of the aluminum foil was calculated and used as the initial value. The hardened resin composition on the aluminum foil was placed in a small oven (product name: LH-114 thermo-humidifier, manufactured by ESPEC) maintained at 200°C, and the mass was measured after 100 hours, 300 hours, 500 hours, and 1000 hours. The mass retention rate (%) of the resin composition after each time period was calculated with the initial value set to 100%. A higher mass retention rate indicates better inhibition of the reaction between the fluorinated phosphor and the resin, indicating better durability of the resin composition. Furthermore, the evaluation used silicone resins selected from those available for purchase. Specifically, for Examples 1 to 9 and Reference Examples 1 to 4, dimethyl silicone resin (product name KER-2936; refractive index 1.41, hereinafter referred to as "dimethyl silicone resin 1") manufactured by Shin-Etsu Chemical Industry Co., Ltd. was used for evaluation. Also, for Examples 10, 11 and Reference Example 1, evaluations were also conducted using dimethyl silicone resin (trade name OE-6351; refractive index 1.41, hereinafter referred to as "dimethyl silicone resin 2") manufactured by Toray Dow Corning Co., Ltd., phenyl silicone resin (trade name OE-6630; refractive index 1.53, hereinafter referred to as "phenyl silicone resin 1") manufactured by Toray Dow Corning Co., Ltd., and phenyl silicone resin with a different refractive index than phenyl silicone resin 1 (refractive index 1.50, hereinafter referred to as "phenyl silicone resin 2").

[0144] (8) Durability assessment The durability of the fluoride fluorides obtained above was evaluated as follows. For each fluoride ...

[0145] Example 1 of manufacturing a light-emitting device Fluoride phosphors from Examples 1 to 9 and Reference Examples 1 to 4 were used as the first phosphor. A β-silicon phosphor with a composition represented by Si 5.81Al 0.19O 0.19N 7.81:Eu and an emission peak wavelength around 540 nm was used as the second phosphor. A resin composition was obtained by mixing phosphor 70, which contains the first phosphor 71 and the second phosphor 72, with silicone resin in a manner where x is approximately 0.280 and y is approximately 0.270 in the CIE 1931 colorimetric system. Subsequently, a molded body 40 with a recess was prepared. A light-emitting element 10 with an emission peak wavelength of 451 nm on the bottom surface of the recess and using gallium nitride compound semiconductor as the material was disposed on the first wire 20. The electrodes of the light-emitting element 10 were then connected to the first wire 20 and the second wire 30 respectively via metal wires 60. Then, a syringe is used to inject the resin composition into the recess of the molded body 40 to cover the light-emitting element 10, so that the resin composition hardens to form a fluorescent component, thereby manufacturing the light-emitting device 1.

[0146] Example 2 of manufacturing a light-emitting device Fluoride phosphors used in Examples 10 to 18 and Reference Examples 3, 5, and 6 were used as the first phosphors. A rare-earth aluminate phosphor having a composition represented by Lu 3Al 5O 11:Ce and an emission peak near 530 nm, a rare-earth aluminate phosphor having a composition represented by Y 3Al 5O 11:Ce and an emission peak near 535 nm, and a nitride phosphor having a composition represented by (Ca,Sr)AlSiN 3:Eu and an emission peak wavelength near 630 nm were combined and used as the second phosphor. A resin composition was obtained by mixing phosphor 70, which contained the first phosphor 71 and the second phosphor 72, with silicone resin, such that x is approximately 0.459 and y is approximately 0.411 in the CIE 1931 colorimetric system. Otherwise, the light-emitting device 2 was manufactured in the same manner as in Example 1.

[0147] Durability assessment 1 For the light-emitting devices 1 or 2 using the fluoride phosphors obtained in Examples 1 to 9 and 15 to 18, and Reference Examples 1 to 4 and 6, a durability test 1 was conducted by storing them in an environmental testing machine at a temperature of 85°C and a relative humidity of 85% for 500 hours. The luminous flux retention rate 1 (%) of the light-emitting device 1 or 2 after durability test 1 was determined when the luminous flux of the light-emitting device 1 or 2 before durability test 1 was set to 100%. The higher the luminous flux retention rate 1, the better the durability against high heat and high humidity. The results are shown in Tables 1, 2, and 5.

[0148] Durability assessment 2 For the light-emitting devices 2 using the various fluoride phosphors obtained in Examples 10 to 18 and Reference Examples 3, 5, and 6, a durability test 2 was conducted for 1000 hours in an environmental testing chamber at an unhumidified temperature of 85°C, driven by a current of 150 mA. The luminous flux retention rate 2 (%) of the light-emitting device 2 after the durability test 2 was determined when the luminous flux of the light-emitting device 2 before the durability test 2 was set to 100%. A higher luminous flux retention rate 2 indicates better durability against high heat. The results are shown in Tables 4 and 5.

[0149] [Table 1] Fluorescent Light-emitting device 1 Fluorescent composition SiO2 addition amount (mass%) SiO2 analytical value (mass%) Peak intensity ratio Average thickness (μm) Quantum efficiency maintenance rate (%) Quality retention rate (%) Luminous flux maintenance rate 1 (%) 100 hours 300 hours 500 hours 1000 hours Reference Example 1 KSF 0 - 100 0 79.2 92 36 32 31 85 Example 1 3 3.3 77 0.13 90.9 100 96 90 68 86 Example 2 10 9.2 44 0.44 95.3 100 97 95 92 90 Example 3 20 14.5 32 0.54 91.8 100 97 95 93 91 See Example 2 KSAF 0 - 100 0 68.9 79 37 34 31 88 Example 4 10 9.1 42 0.45 84.9 100 97 95 91 91

[0150] [Table 2] Fluorescent Light-emitting device 1 Fluorescent composition SiO2 addition amount (mass%) SiO2 analytical value (mass%) Peak intensity ratio Average thickness (μm) Quantum efficiency maintenance rate (%) Quality retention rate (%) Luminous flux maintenance rate 1 (%) 100 hours 300 hours 500 hours 1000 hours See Example 3 KSF 0 - 1.36 50 - 91.7 99 69 49 41 Example 5 10 8.0 1.08 - - 95.1 100 98 96 92 Example 6 10 8.9 1.08 - 0.50 93.2 100 97 96 92 Example 7 10 9.0 1.06 280 - 98.4 100 97 96 92 See Example 4 KSAF 0 - 1.02 20 - 90.3 99 64 45 38 Example 8 10 9.1 0.93 - 0.44 92.6 100 97 95 92 Example 9 10 8.7 0.91 170 - 93.7 99 97 - -

[0151] [Table 3] Fluorescent composition SiO2 addition amount (mass%) SiO2 analytical value (mass%) Mn analytical value (mass%) La analytical value (mass%) Quantum efficiency maintenance rate (%) resin Quality retention rate (%) 100 hours 300 hours 500 hours Reference Example 1 KSF 0 - 1.50 0 79.2 Dimethyl silicone resin 1 92 36 32 Dimethyl silicone resin 2 41 38 37 Phenyl silicone resin 1 88 79 76 Phenyl silicone resin 2 92 88 86 Example 10 KSAF 10 9.0 0.92 0 93.5 Dimethyl silicone resin 1 100 96 95 Dimethyl silicone resin 2 97 86 74 Phenyl silicone resin 1 98 95 93 Phenyl silicone resin 2 100 96 94 Example 11 8.6 0.91 1.03 95.9 Dimethyl silicone resin 1 100 97 96 Dimethyl silicone resin 2 98 92 85 Phenyl silicone resin 1 98 96 95 Phenyl silicone resin 2 97 96 95

[0152] [Table 4] Fluorescent Light-emitting device 2 Fluorescent composition SiO2 addition amount (mass%) SiO2 analytical value (mass%) Mn analytical value (mass%) La analytical value (mass%) TC analytical value (ppm) Quantum efficiency maintenance rate (%) resin Quality retention rate (%) Luminous flux maintenance rate 2 (%) 100 hours 300 hours 1000 hours See Example 3 KSF 0 - 1.50 1.36 50 91.7 Dimethyl silicone resin 1 99 69 41 97.5 See Example 5 KSAF - - 1.00 1.14 - 93.9 98 78 45 96.3 Example 10 10 9.0 0.92 - - 93.5 100 96 92 96.4 Example 11 10 8.6 0.91 1.03 - 95.9 100 97 93 97.7 Example 12 10 8.7 0.92 1.02 260 98.2 100 97 92 98.4 Example 13 6 5.9 0.94 - - 94.9 100 97 90 99.0 Example 14 3 3.0 0.95 - - 96.8 100 97 80 98.7

[0153] [Table 5] Fluorescent Light-emitting device 2 Fluorescent composition SiO2 addition amount (mass%) SiO2 analytical value (mass%) Mn analytical value (mass%) La analytical value (mass%) TC analytical value (ppm) Quantum efficiency maintenance rate (%) resin Quality retention rate (%) Luminous flux maintenance rate 1 (%) Luminous flux maintenance rate 2 (%) 1000 hours See Example 6 KSAF 0 - 1.20 1.05 - 93.3 Dimethyl silicone resin 1 42 98.9 95.8 Example 15 6 5.8 1.13 0.94 560 97.1 92 99.5 96.3 Example 16 5.8 1.13 0.96 400 97.0 92 99.9 96.7 Example 17 6.0 1.13 0.97 1600 96.2 91 97.3 97.3 Example 18 5.8 1.13 0.96 430 97.9 92 100.3 96.8

[0154] The SiO₂ analysis values ​​of the fluoride phosphors in Examples 1 to 4 increased with increasing SiO₂ content. Compared to the peak intensities of the fluoride phosphors in Reference Examples 1 and 2, the peak intensities of Kα rays of element F measured by XRF in the fluoride phosphors of the Examples were all reduced to below 80%. This suggests that the Kα rays of element F are absorbed by the SiO₂ film, and that SiO₂ acts as a film covering the surface of the fluoride particles. Furthermore, the film thickness was calculated to be 0.13 μm or more based on the absorption rates.

[0155] Compared to the fluoride phosphor in Reference Example 1, the fluoride phosphors in Examples 1 to 3 exhibited higher quantum efficiency retention rates. Furthermore, compared to the resin composition containing the fluoride phosphor in Reference Example 1, the resin compositions containing the fluoride phosphors in Examples 1 to 3 showed higher mass retention rates and superior durability. Regarding the durability of the resin compositions, it was observed that, compared to Example 1, which had a thinner average SiO2 film thickness, Examples 2 and 3, with thicker average thicknesses, showed further improved mass retention rates and durability after 500 hours. Compared to Reference Example 2, which changed the composition of the fluoride particles, the fluoride phosphor in Example 4, which covered the SiO2 film with the same composition, showed higher quantum efficiency retention rates in the durability evaluation, and the mass retention rate of the resin composition also increased. That is, fluoride particles containing KSAF in the composition can also achieve the same effect.

[0156] Compared to the light-emitting device 1 using the fluoride phosphor of Reference Example 1, the light-emitting device 1 using the fluoride phosphors of Examples 1 to 3 exhibits a higher luminous flux maintenance rate and superior durability. This demonstrates that using a fluoride phosphor coated with a SiO2 film in the light-emitting device 1 results in higher durability. Compared to the light-emitting device 1 using the fluoride phosphor of Reference Example 2, the light-emitting device 1 using the fluoride phosphor of Example 4 also shows improved durability; the same effect can be achieved with a fluoride phosphor containing KSAF in its composition. Comparing the light-emitting device 1 using the fluoride phosphor of Example 2 with the light-emitting device 1 using the fluoride phosphor of Example 4, it can be seen that the luminous flux maintenance rate 1 of the light-emitting device 1 using the fluoride phosphor of Example 4 is 1% higher than that of the light-emitting device 1 using the fluoride phosphor of Example 2. The fluoride phosphor of Example 4 uses a fluoride phosphor containing KSAF, while the fluoride phosphor of Example 2 uses a fluoride phosphor containing KSF.

[0157] Figure 4 shows the SEM image of the fluoride phosphor obtained in Example 6 obtained by scanning electron microscopy. As shown in Figure 4, the surface of the fluoride phosphor is smooth, and the silicon dioxide covering the fluoride particles is not in the form of particles, but rather a continuous film. Figure 6 shows the SEM image of the fluoride phosphor obtained in Example 8 obtained by scanning electron microscopy. As shown in Figure 6, the silicon dioxide covering the fluoride particles is not in the form of particles; even the fluoride particles containing KSAF are in a continuous film.

[0158] Figure 3 shows an image obtained by observing the cross-section of the fluoride phosphor obtained in Example 6 using a scanning electron microscope. In Figure 3, the gray area corresponds to fluoride particles 2, the white area corresponds to lanthanum phosphate 4, and the dark gray area corresponds to silicon dioxide 6. It can be seen that in the fluoride phosphor, fluoride particles 2 are attached to lanthanum phosphate 4 and are subsequently covered by silicon dioxide 6. Figure 5 shows an image obtained by observing the cross-section of the fluoride phosphor obtained in Example 8 using a scanning electron microscope. In Figure 5, the gray area corresponds to fluoride particles 2, the white area corresponds to lanthanum phosphate 4, and the dark gray area corresponds to silicon dioxide 6. It can be seen that fluoride particles 2 are attached to lanthanum phosphate 4 and are subsequently covered by silicon dioxide 6.

[0159] The SiO2 analysis values ​​of the fluoride phosphors in Examples 5 to 11 were the same as those in Examples 2 and 4. The measured average thicknesses of the SiO2 film obtained by image analysis of the cross-sectional SEM images of the fluoride phosphors in Examples 6 and 8 shown in Figures 3 and 5 were 0.50 μm and 0.44 μm, respectively, which are approximately the same as the average film thicknesses calculated by XRF according to Examples 2 and 4. This confirms that the surface of the fluoride phosphor with attached lanthanum phosphate is also covered by a SiO2 film of the same thickness. Therefore, it is believed that even if the dropping method, dropping time, and stirring speed are changed during the reaction, SiO2 will similarly act as a film covering the fluoride particles.

[0160] The TC analysis values ​​of the fluoride phosphors in Examples 7 and 9 were higher than those in Reference Examples 3 and 4, confirming the presence of carbon. It is believed that this carbon originates from the silane coupling agent. Therefore, it is thought that by performing silane coupling treatment on the fluoride phosphor covered by SiO2, components originating from the silane coupling agent would adhere to the surface of the fluoride phosphor.

[0161] Compared to the fluoride phosphor of Reference Example 3, the fluoride phosphors of Examples 5 to 7 exhibited higher quantum efficiency retention rates. Furthermore, compared to the fluoride phosphor of Reference Example 3, the resin composition in Examples 5 to 7 showed higher mass retention rates and superior durability. Regarding durability, compared to Example 6, Example 7, which underwent silane coupling treatment, showed further improved quantum efficiency retention and enhanced durability. This is because the silane coupling treatment hydrophobically rejuvenated the surface of the SiO2 film. Compared to the fluoride phosphor of Reference Example 4, which consisted of lanthanum phosphate attached to fluoride particles having a second composition (KSAF), the fluoride phosphor of Example 8, which had the same composition (KSAF) and was covered by a SiO2 film, showed higher quantum efficiency retention and higher mass retention rates in the durability evaluation, indicating superior durability for both the fluoride phosphor and the resin composition. Regarding durability, compared to Example 8, Example 9, which underwent silane coupling treatment, showed a further improvement in quantum efficiency retention and durability. Among the fluoride particles with the second composition (KSAF), Example 8, with lanthanum phosphate, exhibited a higher quantum efficiency retention compared to Example 4 without lanthanum phosphate. This improvement was further enhanced by covering the surface of the lanthanum phosphate-coated phosphor with SiO2. In other words, by covering the fluoride phosphor with lanthanum phosphate with a SiO2 film, improved durability can also be achieved.

[0162] Compared to the light-emitting device 1 using the fluoride phosphor in Reference Example 3, the light-emitting device 1 using the fluoride phosphors in Examples 5 to 7 exhibits a higher luminous flux maintenance rate 1 and superior durability. It is evident that the light-emitting device 1 using the fluoride phosphor in Example 7, which underwent silane coupling treatment, further improved the luminous flux maintenance rate 1 and enhanced durability. The quantum efficiency maintenance rate of the fluoride phosphor is closely related to the luminous flux maintenance rate 1 of the light-emitting device 1. By covering the fluoride phosphor with a SiO2 film, durability is improved; further improvements in durability can be achieved through silane coupling treatment. Compared to the light-emitting device 1 using the fluoride phosphor in Reference Example 4, the durability of the light-emitting device 1 using the fluoride particles in Examples 8 and 9 is also improved. Even with fluoride particles coated with lanthanum phosphate and having a second composition (KSAF), covering them with a SiO2 film also enhances durability.

[0163] If the phosphor settling status is confirmed by observing the cross-section of the light-emitting device 1, the phosphor settling is the most in the light-emitting device of Example 7, which has undergone silane coupling treatment. It is believed that the affinity with the resin is increased by silane coupling treatment, making the phosphor settling easier.

[0164] Compared to the fluoride particles of Reference Example 1, the fluoride phosphors of Examples 10 and 11 exhibited higher quantum efficiency retention rates. Furthermore, compared to the fluoride particles of Reference Example 1, the resin compositions of the fluoride phosphors of Examples 10 and 11 showed higher mass retention rates and superior durability. When using phenyl silicone resins 1 and 2, the mass retention rate of the fluoride particles of Reference Example 1 also increased, but the mass retention rates of Examples 10 and 11 were even higher. When using dimethyl silicone resins 1 and 2, the mass retention rate of the fluoride particles of Reference Example 1 decreased significantly, but the mass retention rates of Examples 10 and 11 were higher. In particular, the high mass retention rate of Example 11 was achieved by covering the surface of the phosphor with a SiO2 film, resulting in a higher effect. In any resin, the resin compositions of Example 10, in which KSAF fluoride particles are covered by a SiO2 film, and of Example 11, in which the surface of the phosphor with attached lanthanum phosphate is covered by a SiO2 film, exhibit superior durability compared to the composition of Reference Example 1, which contains KSF fluoride particles.

[0165] Compared to the fluoride phosphor in Reference Example 5, the fluoride phosphors in Examples 11 to 14 exhibit higher quantum efficiency retention. The quality retention of the resin composition is also higher, and the durability of the resin composition is excellent. Compared to the light-emitting device 2 using the fluoride phosphor in Reference Example 5, the light-emitting device 2 using the fluoride phosphors in Examples 10 to 14 exhibits higher luminous flux retention and superior durability. The light-emitting devices 2 using the fluoride phosphors in Examples 11 and 12 employ fluoride phosphors with a surface covered by SiO2 and coated with lanthanum phosphate. These light-emitting devices exhibit superior durability compared to the light-emitting device 2 using the fluoride phosphor in Example 10. This is believed to be because the adhesion of the silicon dioxide coating is improved by lanthanum phosphate, and coating peeling is suppressed. Furthermore, it is believed that for the light-emitting device 2 using the fluoride phosphor of Example 12, the affinity with the resin is improved through silane coupling treatment, thereby making the phosphor easier to settle and improving its adhesion to the resin, thus achieving a higher effect. Compared with the light-emitting device 2 using the fluoride phosphor of Example 10, the light-emitting devices 2 using the fluoride phosphors of Examples 13 and 14 with reduced SiO2 concentration have better durability. It is believed that this is because by reducing the SiO2 concentration, the cracking of the SiO2 film is suppressed, thereby inhibiting contact between the cracked areas and the external environment. Compared to the light-emitting device 2 using fluoride particles with lanthanum phosphate and KSF composition attached in Reference Example 3, the light-emitting device 2 using fluoride phosphors with second composition (KSAF) covered by SiO2 film using fluoride particles with second composition (KSAF) in Examples 13 and 14, and the light-emitting device 2 using fluoride phosphors with lanthanum phosphate and second composition (KSAF) covered by SiO2 film using Examples 11 and 12 have superior durability.

[0166] Compared to the fluoride phosphor of Reference Example 6, the fluoride phosphors of Examples 15 to 18 exhibited higher quantum efficiency retention rates. It was also believed that the quality retention rate of the resin composition was higher, resulting in excellent durability as a powder, and that the affinity with the resin was improved through silane coupling treatment. In durability evaluation 1, the luminous flux retention rate 1 of the light-emitting device 2 using the fluoride phosphor of Reference Example 6 was higher than that of the light-emitting device 2 using the fluoride phosphor of Examples 15, 16, and 18. Furthermore, in durability evaluation 2, the luminous flux retention rate 2 of the light-emitting device 2 using the fluoride phosphor of Examples 15 to 18 was higher than that of the light-emitting device 2 using the fluoride phosphor of Reference Example 6. The main reason for this is, for example, that in the silane coupling agent, the methoxy or ethoxy group hydrolyzes, forming hydrogen bonds with the -OH groups on the phosphor surface, and chemically bonding occurs through heating. Therefore, silane coupling agents are difficult to bond to fluoride particles of the first composition (KSF) or the second composition (KSAF) with fewer -OH groups on the surface. On the other hand, it is believed that the fluoride phosphor with more -OH groups on the surface of the fluoride particles covered by SiO2 has easier bonding, thus improving the affinity with the resin and achieving the effects described above. In particular, the fluoride phosphors of Examples 15 to 18 have a second composition with a surface covered by SiO2 on which lanthanum phosphate is attached. It is believed that the adhesion of the SiO2 film is improved by the lanthanum phosphate, and cracking or peeling of the coating is suppressed, thereby making it easier for the silane coupling agent to bond uniformly and improving the affinity with the resin.

[0167] The fluoride phosphor of the present invention is particularly useful in light-emitting devices that use light-emitting diodes as excitation light sources, such as suitable for lighting sources, light sources for LED displays or liquid crystal backlights, signal machines, lighting switches, various sensors, various indicators, and small flash units.

[0168] The entire contents disclosed in Japanese Patent Application No. 2021-091754 (filed May 31, 2021), Japanese Patent Application No. 2021-130074 (filed August 6, 2021), Japanese Patent Application No. 2021-141629 (filed August 31, 2021), and Japanese Patent Application No. 2022-083514 (filed May 23, 2022) are incorporated herein by reference. All documents, patent applications, and technical specifications described herein are incorporated by reference to the same extent as described in detail below.

Claims

1. A fluoride phosphor comprising fluoride particles and an oxide covering at least a portion of the surface of the fluoride particles, wherein the oxide comprises at least one element selected from the group consisting of Si, Al, Ti, Zr, Sn, and Zn, and the content of the oxide is 2% by mass or more and 30% by mass or less relative to the fluoride phosphor, wherein the fluoride particles have the following composition: containing element M, an alkali metal, Mn, and F, comprising at least one element selected from the group consisting of Group 4, Group 13, and Group 14 elements, and when the mole number of the alkali metal is set to 2, the mole number of Mn is greater than 0 and less than 0.2, the mole number of element M is greater than 0.8 and less than 1, and the mole number of F is greater than 5 and less than 7. The fluoride particles are disposed on their surface with a rare earth phosphate containing at least one rare earth element selected from the group consisting of La, Ce, Dy and Gd, and the oxides are used to coat the fluoride particles with the rare earth phosphates.

2. The fluoride phosphor of claim 1, wherein the fluoride particles contain at least one of Si and Ge as element M in their composition, and when the mole number of the alkali metal is set to 2, the total mole number of Si, Ge and Mn is 0.9 or more and 1.1 or less.

3. The fluoride phosphor of claim 1 or 2, wherein the fluoride particles have the composition represented by the following formula (1): A1c[M11-bMnbFd] (1) (in formula (1), A1 includes at least one element selected from the group consisting of Li, Na, K, Rb and Cs; M1 includes at least one element selected from Si and Ge, and may further include at least one element selected from the group consisting of Group 4 and Group 14 elements; b satisfies 0 < b < 0.2, c is the absolute value of the charge of the [M21-bMnbFd] ion, and d satisfies 5 < d < 7).

4. The fluoride phosphor of claim 1, wherein the fluoride particles contain Si and Al as element M in their composition, and when the mole number of the alkali metal is set to 2, the total mole number of Si, Al and Mn is 0.9 or more and 1.1 or less, and the mole number of Al is more than 0 and less than 0.

1.

5. A fluoride phosphor as claimed in claim 1 or 4, wherein the fluoride particles have the composition represented by the following formula (2): A2f[M21-eMneFg] (2) (in formula (2), A2 contains at least one element selected from the group consisting of Li, Na, K, Rb and Cs; M2 contains at least Si and Al, and may further contain at least one element selected from the group consisting of Group 4, Group 13 and Group 14 elements; e satisfies 0 < e < 0.2, f is the absolute value of the charge of the [M21-eMneFg] ion, and g satisfies 5 < g < 7).

6. A fluoride phosphor as claimed in claim 1 or 2, wherein the oxide comprises silicon.

7. The fluoride phosphor of claim 1 or 2, wherein the average thickness of the oxide is more than 0.1 μm and less than 1.8 μm.

8. The fluoride phosphor of claim 1 or 2, wherein, in the fluorescence X-ray elemental analysis, the ratio of the peak intensity of Kα rays of element F in the fluoride phosphor to the peak intensity of Kα rays of element F in the fluoride particles is 80% or less.

9. The fluoride phosphor of claim 1 or 2, wherein the rare earth phosphate contains lanthanum.

10. The fluoride phosphor of claim 1 or 2, wherein the content of the rare earth phosphate is 0.1% by mass or more and 20% by mass, calculated based on the content of the rare earth elements.

11. A method of manufacturing a fluoride phosphor as described in any one of claims 1 to 10, comprising: Prepare fluoride particles having the following composition: containing at least one element M, an alkali metal, Mn, and F selected from the group consisting of elements selected from Group 4, Group 13, and Group 14, and when the mole number of the alkali metal is set to 2, the mole number of Mn is greater than 0 and less than 0.2, the mole number of element M is greater than 0.8 and less than 1, and the mole number of F is greater than 5 and less than 7. In a liquid medium, the prepared fluoride particles are contacted with at least one rare earth ion selected from the group consisting of La, Ce, Dy and Gd, and phosphate ions to obtain fluoride particles coated with rare earth phosphates; and by contacting the fluoride particles coated with rare earth phosphates with at least one metal alkoxide selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn in a liquid medium, the oxide derived from the metal alkoxide covers at least a portion of the surface of the fluoride particles coated with rare earth phosphates in an amount of 2% to 30% by mass relative to the fluoride phosphor.

12. The manufacturing method of claim 11, wherein the prepared fluoride particles contain at least one of Si and Ge as element M in their composition, and when the mole number of the alkali metal is set to 2, the total mole number of Si, Ge and Mn is 0.9 or more and 1.1 or less.

13. The manufacturing method of claim 12, wherein the prepared fluoride particles have the composition represented by the following formula (1): A1c[M11-bMnbFd] (1) (in formula (1), A1 includes at least one element selected from the group consisting of Li, Na, K, Rb and Cs; M1 includes at least one element selected from Si and Ge, and may further include at least one element selected from the group consisting of Group 4 elements and Group 14 elements; b satisfies 0 < b < 0.2, c is the absolute value of the charge of the [M21-bMnbFd] ion, and d satisfies 5 < d < 7).

14. The manufacturing method of claim 11, wherein the prepared fluoride particles contain Si and Al as element M in their composition, and when the mole number of the alkali metal is set to 2, the total mole number of Si, Al and Mn is 0.9 or more and 1.1 or less, and the mole number of Al is more than 0 and less than 0.

1.

15. The manufacturing method of claim 14, wherein the prepared fluoride particles have the composition represented by the following formula (2): A2f[M21-eMneFg] (2) (in formula (2), A2 contains at least one element selected from the group consisting of Li, Na, K, Rb and Cs; M2 contains at least Si and Al, and may further contain at least one element selected from the group consisting of Group 4, Group 13 and Group 14 elements; e satisfies 0 < e < 0.2, f is the absolute value of the charge of the [M21-eMneFg] ion, and g satisfies 5 < g < 7).

16. The manufacturing method of claim 11, further comprising, after coating at least a portion of the surface of the fluoride particles with an oxide derived from the aforementioned metal alkoxide, performing a silane coupling treatment.

17. The manufacturing method of claim 11, wherein the metal alkoxide contacted in the liquid medium comprises at least one selected from the group consisting of tetramethoxysilane, tetraethoxysilane and tetraisopropoxysilane.

18. A light-emitting device comprising: a fluorescent component including a fluorinated phosphor and a resin as claimed in any one of claims 1 to 10; and a light-emitting element having a peak emission wavelength in a wavelength range of 380 nm to 485 nm.

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