JP2022184763A - Fluoride fluorescent, manufacturing method thereof and light-emitting device - Google Patents

Abstract

To provide a fluoride fluorescent capable of improving reliability in a light-emitting device.SOLUTION: A fluoride fluorescent includes fluoride particles, and an oxide at least partially covering surfaces of the fluoride particles. The oxide contains at least one selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn, and a content thereof is 2 mass% or more and 30 mass% or less. The fluoride particles contain: an element M containing at least one selected from the group consisting of a group 4 element, a group 13 element and a group 14 element; an alkali metal; Mn; and F. When the number of moles of the alkali metal is specified as 2, the number of moles of the element Mn is more than 0 and less than 0.2; the number of moles of the element M is more than 0.8 and less than 1; and the number of moles of F is more than 5 and less than 7.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present disclosure relates to a fluoride phosphor, a manufacturing method thereof, and a light emitting device.

Light-emitting devices in which light-emitting elements and phosphors are combined are used in a wide range of fields such as lighting, vehicle-mounted lighting, displays, and backlights for liquid crystals. For example, phosphors used in light-emitting devices for backlighting liquid crystals are required to have high color purity, that is, to have a narrow half width of the emission peak. Fluoride phosphors to which Mn is added are known as red-emitting phosphors having a narrow half-value width of an emission peak.

For example, Patent Document 1 describes coating a manganese-doped red phosphor with aluminum oxide or the like in order to reduce the problem of instability due to deterioration of the manganese-doped red phosphor. It is also described as a light emitting device with a fluorescent member containing a doped red phosphor and a resin.

Japanese translation of PCT publication No. 2019-525974

A light-emitting device having a fluorescent member containing a fluoride phosphor and a resin may be less reliable as a light-emitting device depending on the environment in which the light-emitting device is used. An object of one aspect of the present disclosure is 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.

A first aspect is a fluoride phosphor containing fluoride particles and an oxide covering at least part of the surface of the fluoride particles. The oxide contains at least one 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 contain an element M containing at least one selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, an alkali metal, Mn, and F, and an alkali metal When the number of moles of is 2, the number of moles of Mn is more than 0 and less than 0.2, the number of moles of element M is more than 0.8 and less than 1, and the number of moles of F is 5 It has a composition that is greater than and less than 7.

A second aspect is a method for producing a fluoride phosphor, comprising preparing fluoride particles, the prepared fluoride particles, and selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn By contacting a metal alkoxide containing at least one species in a liquid medium, the oxide derived from the metal alkoxide is 2% by mass or more and 30% by mass or less with respect to the fluoride phosphor, and at least one surface of the fluoride particles. and covering the part. The fluoride particles contain an element M containing at least one selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, an alkali metal, Mn, and F, and an alkali metal When the number of moles of is 2, the number of moles of Mn is more than 0 and less than 0.2, the number of moles of element M is more than 0.8 and less than 1, and the number of moles of F is 5 It has a composition that is greater than and less than 7.

A third aspect is a method for producing a fluoride phosphor, comprising preparing fluoride particles, and selecting from the group consisting of La, Ce, Dy and Gd, the prepared fluoride particles in a liquid medium. contacting rare earth ions containing at least one of the above with phosphate ions to obtain fluoride particles to which a rare earth phosphate is attached, the fluoride particles to which the rare earth phosphate is attached, Si, Al, By contacting a metal alkoxide containing at least one selected from the group consisting of Ti, Zr, Sn and Zn in a liquid medium, the oxide derived from the metal alkoxide is 2% by mass with respect to the fluoride phosphor. and covering at least a portion of the surface of the fluoride particles to which the rare earth phosphate is attached with 30% by mass or less. The fluoride particles contain an element M containing at least one selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, an alkali metal, Mn, and F, and an alkali metal When the number of moles of is 2, the number of moles of Mn is more than 0 and less than 0.2, the number of moles of element M is more than 0.8 and less than 1, and the number of moles of F is 5 It has a composition that is greater than and less than 7.

A fourth aspect is a light-emitting device comprising a fluorescent member containing the fluoride phosphor of the first aspect and a resin, and a light-emitting element having an emission peak wavelength in a wavelength range of 380 nm or more and 485 nm or less.

According to one aspect of the present disclosure, it is possible 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.

1 is a schematic cross-sectional view showing an example of a light-emitting device containing a fluoride phosphor; FIG. It is an example of a backscattered electron image obtained by a scanning electron microscope (SEM) of a fluoride phosphor. 10 is an example of a cross-sectional SEM image of a fluoride phosphor according to Example 6. FIG. 10 is an example of an SEM image of a fluoride phosphor according to Example 6. FIG. It is an example of a cross-sectional SEM image of a fluoride phosphor according to Example 8. 10 is an example of an SEM image of a fluoride phosphor according to Example 8. FIG.

In this specification, the term "process" is not only an independent process, but even if it cannot be clearly distinguished from other processes, it is included in this term as long as the intended purpose of the process is achieved. . In addition, the content of each component in the composition means the total amount of the plurality of substances present in the composition unless otherwise specified when there are multiple substances corresponding to each component in the composition. Furthermore, the upper and lower limits of the numerical ranges described herein can be combined by arbitrarily selecting the numerical values exemplified as the numerical ranges. In this specification, the relationship between color names and chromaticity coordinates, the relationship between wavelength ranges of light and color names of monochromatic light, etc. conform to JIS Z8110. The half width of the phosphor means the wavelength width (full width at half maximum; FWHM) of the emission spectrum at which the emission intensity is 50% of the maximum emission intensity in the emission spectrum of the phosphor. The median diameter of the phosphor is the volume-based median diameter, and refers to the particle size corresponding to 50% of the cumulative volume from the small diameter side in the volume-based particle size distribution. The particle size distribution of the phosphor is measured by a laser diffraction method using a laser diffraction particle size distribution analyzer. Hereinafter, embodiments of the present invention will be described in detail. However, the embodiments shown below exemplify a fluoride phosphor, a method for producing the same, and a light-emitting device for embodying the technical idea of the present invention. It is not limited to the body, its manufacturing method and light emitting device.

Fluoride Phosphor The fluoride phosphor may comprise fluoride particles and an oxide covering at least part of the surface of the fluoride particles. The oxide contains at least one 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 or more and 30% by mass or less with respect to the fluoride phosphor. The fluoride particles contain an element M containing at least one selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, an alkali metal, Mn, and F, and an alkali metal When the number of moles of is 2, the number of moles of Mn is more than 0 and less than 0.2, the number of moles of element M is more than 0.8 and less than 1, and the number of moles of F is 5 It has a composition that is greater than and less than 7.

By covering at least part of the surface of the fluoride particles having a specific composition with a predetermined amount of specific oxide, for example, moisture resistance is improved. As a result, the reliability of the light-emitting device provided with the fluorescent member containing the fluoride phosphor and the resin can be improved. For example, reduction in mass of the fluorescent member is suppressed in a high-temperature environment or a high-humidity environment. The decrease in the mass of the fluorescent member is considered to be mainly due to the decrease in the amount of resin. Direct contact between the fluoride particles and the resin in a high-temperature environment or a high-humidity environment is thought to cause some kind of reaction, resulting in scattering of decomposition products in which some of the interatomic bonds of the resin are broken. By covering the fluoride particles with a certain amount of oxide, which is believed to be more chemically stable than the fluoride particles, direct contact between the resin and the fluoride particles is suppressed and reaction is suppressed and the amount of resin is maintained. Since the resin also functions as a protective member for the phosphor, it is conceivable that a reduction in the amount of the resin makes the phosphor more susceptible to the effects of the external environment including moisture, accelerating deterioration of the phosphor. Also, due to the decrease in the amount of resin, for example, the shape of the light emitting surface of the fluorescent member in the light emitting device shown in FIG. For this reason, less light is extracted to the outside of the light emitting device, and the luminous flux of the light emitting device may decrease.

The fluoride particles constituting the fluoride phosphor should contain at least a Mn-activated fluorescent substance, and may consist of only the Mn-activated fluorescent substance. In the composition of the fluoride particles, when the number of moles of the alkali metal is 2, the number of moles of Mn may be more than 0 and less than 0.2, preferably 0.01 or more and 0.12 or less. good. In the composition of the fluoride particles, when the number of moles of the alkali metal is 2, the number of moles of the element M may be more than 0.8 and less than 1, preferably 0.88 or more and 0.99 or less. It's okay. When the number of moles of alkali metal is 2, the composition of the fluoride particles may be such that the number of moles of F is more than 5 and less than 7, preferably 5.9 or more and 6.1 or less. The composition of fluoride particles can be measured, for example, by inductively coupled plasma (ICP) optical emission spectroscopy.

The alkali metal in the composition of the fluoride particles may contain at least one selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb) and cesium (Cs). The alkali metal contains at least potassium (K) and may contain at least one selected from the group consisting of lithium (Li), sodium (Na), rubidium (Rb) and cesium (Cs). The ratio of the number of moles of K to the total number of moles of alkali metals in the composition may be, for example, 0.90 or more, preferably 0.95 or more, or 0.97 or more. The upper limit of the molar ratio of K may be, for example, 1 or 0.995 or less. In the composition of the fluoride particles, part of the alkali metals may be replaced with ammonium ions (NH ₄ ⁺ ). When part of the alkali metal is replaced by ammonium ions, the ratio of the number of moles of ammonium ions to the total number of moles of alkali metal 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 ratio of the number of moles of ammonium ions may be, for example, greater than 0, preferably 0.005 or more.

The 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. Examples of Group 4 elements include titanium (Ti), zirconium (Zr), hafnium (Hf), and the like, and may contain at least one selected from the group consisting of these. Examples of Group 13 elements include boron (B), aluminum (Al), gallium (Ga), indium (In), thallium (Tl) and the like, including at least one selected from the group consisting of these you can stay Group 14 elements include carbon (C), silicon (Si), germanium (Ge), tin (Sn), etc., and may contain at least one selected from the group consisting of these. The element M may contain at least one Group 14 element, preferably at least one of Si and Ge, more preferably at least Si. In addition, the element M may contain at least one Group 13 element and at least one Group 14 element, preferably at least Al and at least one of Si and Ge. Preferably, at least Al and Si may be included.

The first composition, which is one aspect of the composition of the fluoride particles, may contain at least one selected from the group consisting of Group 4 elements and Group 14 elements as the element M, preferably from Group 14 elements It may contain at least one selected from the group consisting of, more preferably at least one of Si and Ge, still more preferably at least Si. In the first composition of the fluoride particles, the total number of moles of Si, Ge, and Mn may be 0.9 or more and 1.1 or less, preferably 0.95 or more, with respect to the number of moles of the alkali metal of 2. It may be 1.05 or less, or 0.97 or more and 1.03 or less.

The first composition of the fluoride particles may be a composition represented by the following formula (1).
A ¹ _c [M ¹ _1-b Mn _b F _d ] (1)

In formula (1), ^A1 may contain at least one selected from the group consisting of Li, Na, K, Rb and Cs. ^M1 contains at least one of Si and Ge, and may further contain 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−b Mn _b F _d ] ion, and d satisfies 5<d<7.

A ¹ in formula (1) contains at least K and may further contain at least one selected from the group consisting of Li, Na, Rb and Cs. Also, A ¹ may be partially substituted with an ammonium ion (NH ₄ ⁺ ). When part of A ¹ is replaced with ammonium ions, the ratio of the number of moles of ammonium ions to the total number of moles of A ¹ 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 ratio of the number of moles of ammonium ions may be, for example, greater than 0, preferably 0.005 or more.

b in formula (1) 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. c 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. d may preferably be 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.

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

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

The second composition, which is one aspect of the composition of the fluoride particles, contains at least one selected from the group consisting of Group 4 elements and Group 14 elements as the element M, and at least one Group 13 element. preferably at least one selected from the group consisting of Group 14 elements and at least one Group 13 element, more preferably at least Si and Al. In addition, in the second composition of the fluoride particles, the total number of moles of Si, Al, and Mn may be 0.9 or more and 1.1 or less, preferably 0.95, with respect to the number of moles of the alkali metal of 2. It may be greater than or equal to 1.05 or less, or greater than or equal to 0.97 and less than or equal to 1.03. Furthermore, in the second composition of the fluoride particles, the number of moles of Al may be more than 0 and 0.1 or less, preferably more than 0 and 0.03 or less, and 0 0.002 or more and 0.02 or less, or 0.003 or more and 0.015 or less.

The second composition of the fluoride particles may be a composition represented by the following formula (2).
A ² _f [M ² _1-e Mn _e F _g ] (2)

In formula (2), ^A2 contains at least K and may further contain at least one selected from the group consisting of Li, Na, 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 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−e Mn _e F _g ] ion, and g satisfies 5<g<7.

A ² in Formula (2) may be partially substituted with an ammonium ion (NH ₄ ⁺ ). When part of ^A2 is replaced by ammonium ions, the ratio of the number of moles of ammonium ions to the total number of moles of ^A2 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 ratio of the number of moles of ammonium ions may be, for example, greater than 0, preferably 0.005 or more.

e in formula (2) 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 may preferably be 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.

Furthermore, the fluoride particles of the second composition may have a second theoretical composition represented by the following formula (2a).
^A22Si1 _{- pAlpF6 -p :} Mn (2a)

In formula (2a), ^A2 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.

The fluoride particles having the second composition may have irregularities, grooves, etc. on the particle surface. The state of the particle surface can be evaluated, for example, by measuring the angle of repose of powder composed of fluoride particles. The angle of repose of the powder of fluoride particles having the second composition 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.

Since the fluoride particles having the second composition have unevenness, grooves, etc. on the surface, for example, when the fluoride particles are covered with a predetermined amount of a specific oxide, the contact area between the fluoride particles and the oxide is large. Therefore, a strong bond can be obtained between the fluoride particles and the oxide, and the fluoride particles can be coated with an oxide film that is difficult to peel off due to an external force. In addition, in the step of covering the fluoride particles with a predetermined amount of a specific oxide, it is possible to cover the fluoride particles with a predetermined amount of oxide even when using a relatively small amount of the oxide raw material. Become. Similarly, when the surface of the fluoride particles is covered with the rare earth phosphate, or when the oxide covers the fluoride particles via the rare earth phosphate, the fluoride phosphor has unevenness, grooves, etc. on the surface. By having the Fluoride particles can be coated with a rare earth phosphate film that is more strongly bound to the acid salt and is not easily peeled off by an external force during manufacture of the light emitting device. In addition, in the step of covering the fluoride particles with a predetermined amount of a specific rare earth phosphate, even if a relatively small amount of raw material for the rare earth phosphate is used, the fluoride particles can be coated with a predetermined amount of the rare earth phosphate. can be covered.

The volume-based median diameter of the fluoride particles may be, for example, 5 μm or more and 90 μm or less, preferably 10 μm or more and 70 μm or less, or 15 μm or more and 50 μm or less, from the viewpoint of improving luminance. The particle size distribution of the fluoride particles may, for example, exhibit a single-peak particle size distribution, preferably a single-peak particle size distribution with a narrow distribution width, from the viewpoint of improving luminance.

The fluoride phosphor may have an oxide covering at least part of the surface of the fluoride particles. The oxide may cover the surface of the fluoride particles in the form of a film, or may be arranged on the surfaces of the fluoride particles as an oxide layer. In addition, the oxide film covering the surface of the fluoride particles is not limited to a state in which no cracks are present at all. Cracks may be present. In addition, although it is preferable that the oxide film covering the surface of the fluoride particles completely cover the entire surface, a part of the oxide film may be partially missing, and the fluoride particles may be partially coated with the fluoride particles to the extent that the effect can be obtained. Part of the particle surface may be exposed. The oxide coverage of fluoride particles in the fluoride phosphor may be, for example, 50% or more, preferably 80% or more, or 90% or more. The oxide coverage of the fluoride particles is calculated as the ratio of the area covered by the oxide to the surface area of the fluoride particles.

The oxide may contain at least one selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn. That is, oxides include silicon oxide (e.g., SiOx, where x may be 1 or more and 2 or less, preferably 1.5 or more and 2 or less, or about ₂ ), aluminum oxide (e.g., _Al2O3 ), oxide containing at least one selected from the group consisting of titanium (e.g. TiO ₂ ), zirconium oxide (e.g. ZrO ₂ ), tin oxide (e.g. SnO, SnO ₂ etc.) and zinc oxide (e.g. ZnO) It may well contain at least silicon oxide. The oxide may consist of only one kind, or may contain two or more kinds.

The content of the oxide in the fluoride phosphor may be from 2% by mass to 30% by mass, preferably from 5% by mass to 20% by mass, or from 8% by mass to 15% by mass. % or less. The oxide content in the fluoride phosphor can be determined, for example, when the oxide is silicon oxide, by inductively coupled plasma (ICP) emission spectroscopy to determine oxide-covered fluoride particles and oxide-free fluoride particles. The amount of each constituent element contained in the oxide particles is analyzed, and the molar ratio of each constituent element is calculated so that the number of moles of the alkali metal is two. The difference in the molar ratio of silicon before and after covering with oxide is converted to the mass of silicon oxide (e.g., SiO ₂ ), and the mass of fluoride particles (fluoride phosphor) covered with oxide is 100% by mass. A content of silicon (eg, SiO ₂ ) is calculated. When the oxide content is within the above range, the reliability of the light-emitting device can be further improved.

In fluoride phosphors, the fluoride particles may be covered with an oxide layer. The average thickness of the oxide layer covering the fluoride particles may be, for example, 0.1 μm or more and 1.8 μm or less, preferably 0.15 μm or more and 1.0 μm or less, or 0.20 μm or more and 0.8 μm or less. good. The average thickness of the oxide layer in the fluoride phosphor is, for example, a cross-sectional image of the fluoride phosphor, in which the thickness of the layer identified as the oxide layer is actually measured at several locations, and the arithmetic mean is the measured average thickness. It's okay. Moreover, the average thickness of the oxide layer in the fluoride phosphor may be a theoretical thickness calculated from the Kα ray intensity ratio of the F element, which will be described later. The theoretical thickness is obtained from the ratio of the peak intensity of the Kα ray of the F element in the fluoride phosphor covered with the oxide to the peak intensity of the Kα ray of the F element in the fluoride particles not covered with the oxide layer, CXRO (The Center for X-Ray Optics) database. The theoretical thickness is calculated as a value obtained by averaging the existence of defects such as cracks and chips in the oxide layer.

In the fluoride phosphor, since the fluoride particles are covered with oxide, the peak intensity of characteristic X-rays derived from the fluoride particles decreases according to the amount of oxide covering the fluoride particles. Therefore, by evaluating the peak intensity of the characteristic X-rays derived from the fluoride particles in the fluoride phosphor, it is possible to evaluate the oxide coating state. Specifically, in the fluorescent X-ray (XRF) elemental analysis method, the ratio of the peak intensity of the Kα ray of the F element in the fluoride phosphor to the peak intensity of the Kα ray of the F element in the fluoride particles is, for example, 80%. or less, preferably 70% or less, or 60% or less. The lower limit of the peak intensity ratio may be, for example, 20% or more. When the ratio of the peak intensity of the Kα ray of the F element in the fluoride phosphor is within the above range, the reliability of the light emitting device can be more effectively improved.

In the fluoride phosphor, the rare earth phosphate may be arranged on the surface of the fluoride particles, and the oxide may cover the fluoride particles via the rare earth phosphate. This tends to further improve the moist heat resistance of the fluoride phosphor. In addition, the adhesion of the oxide to the fluoride particles tends to be improved, and the coatability with the oxide tends to be further improved. The rare earth phosphate placed on the surface of the fluoride particles may adhere to the surfaces of the fluoride particles as particles, or may coat the surfaces of the fluoride particles as a film or layer. It may preferably adhere to the surface of the fluoride particles as particles.

The rare earth phosphate may contain at least one rare earth element selected from the group consisting of lanthanum (La), cerium (Ce), dysprosium (Dy) and gadolinium (Gd), and preferably contains at least lanthanum. can be

The content of the rare earth phosphate in the fluoride phosphor may be, for example, 0.1% by mass or more and 20% by mass or less, preferably 0.2% by mass or more and 15% by mass or less, as the content of the rare earth element. Alternatively, it may be 0.3% by mass or more and 10% by mass or less.

The surface of the fluoride phosphor may be treated with a coupling agent. That is, a surface treatment layer containing functional groups derived from a coupling agent may be arranged on the surface of the fluoride phosphor. By arranging the surface treatment layer on the surface of the fluoride phosphor, for example, the moisture resistance of the fluoride phosphor is further improved.

The functional group derived from the coupling agent includes, for example, a silyl group having an aliphatic group having 1 to 20 carbon atoms, preferably a silyl group having an aliphatic group having 6 to 12 carbon atoms. . The functional groups derived from the coupling agent may be used singly or in combination of two or more.

Examples of coupling agents include silane coupling agents, titanium coupling agents, and aluminum coupling agents. Examples of silane coupling agents include alkyltrialkoxysilanes such as methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, and decyltriethylsilane; aryltrialkoxysilanes such as trimethoxysilane and styryltrimethoxysilane; vinyltrialkoxysilanes such as vinyltrimethoxysilane; aminoalkyltrialkoxysilanes such as 3-aminopropyltriethoxysilane; and glycidoxyalkyltrialkoxysilanes, etc., and may be at least one selected from the group consisting of these. As the coupling agent, a silane coupling agent is preferred because it is relatively easily available.

In one aspect, the fluoride phosphor may include fluoride particles and a rare earth phosphate disposed on at least a portion of the surface of the fluoride particles. In addition, a fluoride phosphor in which a rare earth phosphate is arranged on at least a part of the surface of fluoride particles is further arranged with a surface treatment layer containing a functional group derived from a coupling agent on the surface. good too. By arranging the rare earth phosphate on the surface of the fluoride particles, for example, the moisture resistance of the fluoride phosphor is improved. As a result, the reliability of the light-emitting device provided with the fluorescent member containing the fluoride phosphor and the resin can be improved. Further, for example, reduction in the mass of the fluorescent member under high temperature or high humidity environment is suppressed. Furthermore, the fluoride phosphor in which the rare earth phosphate is arranged on at least a part of the surface of the fluoride particles has a surface treatment layer containing a functional group derived from a coupling agent on the surface, so that the surface treatment Since the interfacial energy between the fluoride phosphor and the encapsulating resin such as silicone resin is reduced, the fluoride phosphor is easily mixed and dispersed uniformly in the encapsulating resin. Furthermore, when the mixture is injected into the package of the light-emitting device and allowed to stand still, the fluoride phosphor can be deposited uniformly and densely on the light-emitting element (eg, LED chip). Therefore, the temperature of the fluoride phosphor can be kept low when the light-emitting device is driven, and as a result, a light-emitting device with high luminous efficiency and high reliability can be obtained.

From the viewpoint of improving luminance, the volume-based median diameter of the fluoride phosphor may be, for example, 10 μm or more and 90 μm or less, preferably 15 μm or more and 70 μm or less, or 20 μm or more and 50 μm or less. The particle size distribution of the fluoride phosphor may exhibit, for example, a single-peak particle size distribution, preferably a single-peak particle size distribution with a narrow distribution width, from the viewpoint of improving luminance.

A fluoride phosphor is, for example, a phosphor activated by tetravalent manganese ions, and emits red light by absorbing light in the short wavelength region of visible light. The excitation light may be mainly light in the blue region, and the peak wavelength of the excitation light may be within the wavelength range of 380 nm or more and 485 nm or less, for example. The emission peak wavelength in the emission spectrum of the fluoride phosphor may be, for example, within the wavelength range of 610 nm or more and 650 nm or less. The half width of the emission spectrum of the fluoride phosphor may be, for example, 10 nm or less.

When the fluoride particles constituting the fluoride phosphor have the second composition, the fluoride phosphor may have unevenness, grooves, or the like on the particle surface. The angle of repose of the powder made of a fluoride phosphor containing fluoride particles having the second composition 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.

The fluoride phosphor obtained by coating the fluoride particles having the second composition with at least one of the oxide and the rare earth phosphate is coated with at least one of the oxide and the rare earth phosphate, and the It has unevenness, grooves, etc. on its surface. As a result, the contact area between the powders of the fluoride phosphor is reduced due to the irregularities and grooves on the surface of the fluoride phosphor, and aggregation of the powder is suppressed. Therefore, the fluoride phosphor particles can be more uniformly dispersed in the resin composition when manufacturing the light-emitting device. Further, for example, when a dispenser is used in manufacturing a light-emitting device, problems such as clogging of the needle of the dispenser with the fluoride phosphor are less likely to occur. In addition, a light-emitting device with little aggregation of fluoride phosphor particles and little variation in chromaticity can be obtained.

Method for producing fluoride phosphor A first aspect of the method for producing a fluoride phosphor (hereinafter also referred to as a first production method) includes a preparation step of preparing fluoride particles, the prepared fluoride particles, Si, a synthesis step of contacting a metal alkoxide containing at least one selected from the group consisting of Al, Ti, Zr, Sn and Zn in a liquid medium to cover the fluoride particles with an oxide derived from the metal alkoxide; including. In the first manufacturing method, the coating amount of the oxide may be 2% by mass or more and 30% by mass or less with respect to the fluoride phosphor. In addition, the prepared fluoride particles include an element M containing at least one selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, an alkali metal, Mn, F, When the total number of moles of the alkali metal is 2, the number of moles of Mn is more than 0 and less than 0.2, and the number of moles of the element M is more than 0.8 and less than 1, It has a composition in which the number of moles of F is more than 5 and less than 7.

By bringing fluoride particles having a predetermined composition into contact with a metal alkoxide in a liquid medium, a fluoride phosphor in which at least a portion of the surface of the fluoride particles is covered with an oxide derived from the metal alkoxide is efficiently produced. can be produced effectively. In a light-emitting device provided with a fluorescent member containing the obtained fluoride phosphor and resin, for example, the reliability in a high-temperature environment is improved.

In the preparation step, fluoride particles having a predetermined composition are prepared. In the preparation step, fluoride particles may be purchased and prepared, or desired fluoride particles may be manufactured and prepared. The details of the prepared fluoride particles are as described above.

Fluoride particles can be produced, for example, as follows. When the fluoride particles have the first composition, for example, at least one selected from the group consisting of a first complex ion containing tetravalent manganese, a group 4 element and a group 14 element, and a second compound containing fluorine ions It can be produced by a production method including a step of mixing a solution a containing at least a complex ion and hydrogen fluoride with a solution b containing at least an alkali metal containing at least potassium and hydrogen fluoride.

Further, for example, a first solution containing at least a first complex ion containing tetravalent manganese and hydrogen fluoride, a second solution containing at least an alkali metal containing at least potassium and hydrogen fluoride, a Group 4 element and a It can also be produced by a production method including a step of mixing at least one selected from the group consisting of Group 14 elements and a third solution containing at least a second complex ion containing a fluorine ion.

Further, when the fluoride particles have the second composition, the method for producing the fluoride particles having the second composition includes, for example, preparing fluoride particles having the first composition, Al, an alkali metal, and F. Preparing fluoride particles, and subjecting a mixture containing the fluoride particles and the fluoride particles having the first composition to a first heat treatment at a first heat treatment temperature of 600° C. or higher and 780° C. or lower in an inert gas atmosphere. It can be manufactured by a manufacturing method including one heat treatment step. Here, the composition of the fluoride particles containing Al, an alkali metal, and F is such that the ratio of the total number of moles of the alkali metal to the number of moles of Al is 1 or more and 3 or less, and the ratio of the number of moles of F is It may be 4 or more and 6 or less. Alternatively, the ratio of the total number of moles of alkali metals to 1 mole of Al may be 2 or more and 3 or less, and the ratio of the number of moles of F may be 5 or more and 6 or less.

The method for producing a fluoride phosphor further includes a second heat treatment step of subjecting the first heat-treated product after the first heat treatment to a second heat treatment at a second heat treatment temperature of 400° C. or higher to obtain a second heat-treated product. You can

The second heat treatment step may be performed with only the fluoride particles, or the second heat treatment step may be performed with the fluoride particles together with the fluorine-containing substance. This fluorine-containing substance may be in a solid state, a liquid state, or a gaseous state at room temperature. Examples of solid or liquid fluorine-containing substances include NH ₄ F and the like. Examples of gaseous fluorine-containing substances include F ₂ , CHF ₃ , CF ₄ , NH ₄ HF ₂ , HF, SiF ₄ , KrF ₄ , XeF ₂ , XeF ₄ , and NF ₃ . It may be at least one selected from the group consisting of, preferably at least one selected from the group consisting of _F2 and HF.
The second heat treatment temperature may preferably be higher than 400°C, 425°C or higher, 450°C or higher or 480°C or higher. The upper limit of the second heat treatment temperature may be, for example, less than 600°C, preferably 580°C or less, 550°C or less, or 520°C or less. The second heat treatment temperature may be lower than the first heat treatment temperature.

The fluoride particles of the second composition synthesized by the solid phase reaction method in the first heat treatment step have tetravalent Si ions, trivalent Al ions, and tetravalent Mn ions at the same positions in the crystal of the fluoride particles. It is believed that the presence of such a compound is such that it contains a compound having mixed valences. As a result, in proportion to the existence ratio of tetravalent Si ions, trivalent Al ions, and tetravalent Mn ions, there is a shortage of cations having mixed valences at positions in the crystal where fluorine ions should be present. It is believed that vacancies are present to compensate for the charge that is applied.

Here, for example, fluoride particles synthesized by a liquid phase reaction method as disclosed in Japanese Patent Application Laid-Open No. 2010-254933 contain water present in the solution at positions where fluorine ions should exist in the crystals. A large number of hydroxide ions introduced into the crystal from the oxide ions are mixed together with the fluoride ions, and it is considered that these hydroxide ions impair the stability of the fluoride particles. On the other hand, the fluoride particles of the second composition synthesized by the solid-phase reaction method by heat treatment do not use a solution in which hydroxide ions may exist. Oxide ions are not mixed.

In addition, Mn ions having different valences may be mixed in the crystals of the fluoride particles or on the crystal surfaces of the fluoride particles of the second composition synthesized by the solid phase reaction method in the first heat treatment step. When Mn ions with different valences are mixed in the fluoride particles, the valence of the Mn ions can be adjusted to a tetravalent state by further heat-treating while in contact with the fluorine-containing material. This can also increase the luminous efficiency of the fluoride particles.

In the synthesis step, the prepared fluoride particles and a metal alkoxide containing at least one selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn are contacted in a liquid medium to obtain A fluoride phosphor is obtained by covering the fluoride particles with an oxide that dissolves. By solvolyzing the metal alkoxide, an oxide derived from the metal alkoxide can be produced, and a fluoride phosphor containing fluoride particles covered with the produced oxide can be obtained.

The aliphatic group of the alkoxide constituting the metal alkoxide may have, for example, 1 or more and 6 or less carbon atoms, preferably 1 or more and 4 or less carbon atoms, or 1 or more and 3 or less carbon atoms. The metal alkoxide contains at least one selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn, and may contain at least Si. The metal and aliphatic group contained in the metal alkoxide may each be of only one type, or may be contained in combination of two or more types.

Specific examples of metal alkoxides include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, trimethoxyaluminum, triethoxyaluminum, triisopropoxyaluminum, tetramethoxytitanium, tetraethoxytitanium, tetraisopropoxytitanium, and tetramethoxyzirconium. , tetraethoxyzirconium, tetraisopropoxyzirconium, tetraethoxytin, dimethoxyzinc, diethoxyzinc and the like, preferably at least one selected from the group consisting of tetramethoxysilane, tetraethoxysilane and More preferably, it is at least one selected from the group consisting of tetraisopropoxysilane. The metal alkoxide in the synthesis step may be used singly or in combination of two or more.

The addition amount of the metal alkoxide used in the synthesis step may be, for example, 2% by mass or more and 30% by mass or less, preferably 5% by mass or more, with respect to the total mass of the fluoride particles, as an addition amount in terms of oxide. , or 8% by mass or more, and preferably 25% by mass or less, or 20% by mass or less. The amount of metal alkoxide added in the synthesis step may be, for example, 5% by mass or more and 110% by mass or less, preferably 15% by mass or more, relative to the total mass of the fluoride particles as the amount of metal alkoxide added. , or 25% by mass or more, and preferably 90% by mass or less, or 75% by mass or less.

Contacting the fluoride particles with the metal alkoxide takes place in a liquid medium. Examples of the liquid medium include water; alcohol solvents such as methanol, ethanol and isopropyl alcohol; nitrile solvents such as acetonitrile; and hydrocarbon solvents such as hexane. The liquid medium may contain at least water and an alcoholic solvent. When the liquid medium contains an alcohol-based solvent, the content of the alcohol-based solvent in the liquid medium may be, for example, 60% by mass or more, preferably 70% by mass or more. Moreover, the content of water in the liquid medium may be, for example, 4% by mass or more and 40% by mass or less.

Moreover, the liquid medium may further contain a pH adjuster. Examples of pH adjusters that can be used 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 of the liquid medium may be, for example, 1 or more and 6 or less, preferably 2 or more and 5 or less, under acidic conditions. Under alkaline conditions, it may be 8 or more and 12 or less, preferably 8 or more and 11 or less.

The mass ratio of the liquid medium to the fluoride particles may be, for example, 100% by mass or more and 1000% by mass or less, preferably 150% by mass or more, or 180% by mass or more, and preferably 600% by mass or less, Or it may be 300% by mass or less. When the mass ratio of the liquid medium is within the above range, there is a tendency that the fluoride particles can be more uniformly covered with the oxide.

The contact between the fluoride particles and the metal alkoxide can be performed, for example, by adding the metal alkoxide to the suspension containing the fluoride particles. At this time, stirring or the like may be performed as necessary. Further, the contact temperature between the fluoride particles and the metal alkoxide may be, for example, 0° C. or higher and 70° C. or lower, preferably 10° C. or higher and 40° C. or lower. The contact time may be, for example, from 1 hour to 12 hours. The contact time includes the time required for adding the metal alkoxide.

A second aspect of the method for producing a fluoride phosphor (hereinafter also referred to as a second production method) consists of a preparation step of preparing fluoride particles, the prepared fluoride particles, and La, Ce, Dy and Gd. an attachment step of contacting rare earth ions containing at least one lanthanoid selected from the group with phosphate ions in a liquid medium to obtain fluoride particles to which rare earth phosphates are attached; and a solution containing a metal alkoxide containing at least one selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn are brought into contact with an oxide derived from the metal alkoxide, coating the fluoride particles with rare earth phosphates attached thereto. In the second manufacturing method, the coating amount of the oxide may be 2% by mass or more and 30% by mass or less with respect to the fluoride phosphor. In addition, the prepared fluoride particles include an element M containing at least one selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, an alkali metal, Mn, F, When the number of moles of the alkali metal is 2, the number of moles of Mn is more than 0 and less than 0.2, the number of moles of element M is more than 0.8 and less than 1, and F may have a composition in which the number of moles of is greater than 5 and less than 7.

In the second production method, after the rare earth phosphate is attached to the surface of the fluoride particles, the fluoride particles to which the rare earth phosphate is attached are covered with an oxide derived from a metal alkoxide. There is a tendency for the moist heat resistance of the fluoride phosphor to be further improved.

The preparatory steps in the second manufacturing method are similar to the preparatory steps in the first manufacturing method. The synthesis step in the second production method is the same as the synthesis step in the first production method, except that the rare earth phosphate is attached to the fluoride particles used in the synthesis step.

In the adhesion step, the prepared fluoride particles, rare earth ions, and phosphate ions are brought into contact in a liquid medium. As a result, the rare earth phosphate adheres to the surface of the fluoride particles to obtain the fluoride particles having the rare earth phosphate adhered thereto. It is believed that by attaching the rare earth phosphate to the fluoride particles in the liquid medium, the rare earth phosphate is more uniformly attached to, for example, the surfaces of the fluoride particles.

The liquid medium should be capable of dissolving phosphate ions and rare earth ions, and preferably contains at least water in order to facilitate dissolution of these ions. If necessary, the liquid medium may further contain a reducing agent such as hydrogen peroxide, an organic solvent, a pH adjuster, and the like. Examples of organic solvents that the liquid medium may contain include alcohols such as ethanol and isopropanol. Examples of pH adjusters include basic 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. When it is at least the above lower limit, there is a tendency to obtain a sufficient adhesion amount of the rare earth phosphate, and when it is at most the above upper limit, there is a tendency to suppress deterioration of the luminous properties of the fluoride phosphor. When the liquid medium contains water, the content of water 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.

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, and is, for example, 1000% by mass or less or 800% by mass or less. When the mass ratio of the liquid medium is equal to or higher than the above lower limit, the rare earth phosphate can be easily adhered to the surface of the fluoride particles more uniformly. There is a tendency for the adhesion rate of the salt to the fluoride particles to be further improved.

The liquid medium preferably contains phosphate ions, more preferably water and phosphate ions. When the liquid medium contains phosphate ions, the prepared fluoride particles and the liquid medium are mixed, and further mixed with a solution containing rare earth ions to obtain phosphate ions and rare earth ions in the liquid medium containing the fluoride particles. can be brought into contact with When the liquid medium contains phosphate ions, the phosphate ion concentration 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. When the phosphate ion concentration in the liquid medium is at least the above lower limit, the amount of the liquid medium does not become too large, the elution of the constituent components from the fluoride particles is suppressed, and the properties of the fluoride phosphor are maintained satisfactorily. Tend. Further, when the content is equal to or less than the above upper limit, there is a tendency that the uniformity of deposits on the fluoride particles is improved.

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.

When the liquid medium contains phosphate ions, it may be prepared by dissolving a compound serving as a phosphate ion source in the liquid medium, or by mixing a solution containing the phosphate ion source with the liquid medium. . Phosphate ion sources include, for example, 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; Alkali metal dihydrogen phosphates such as sodium hydrogen and potassium dihydrogen phosphate; alkali metal hexametaphosphates such as sodium hexametaphosphate and potassium hexametaphosphate; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; phosphoric acid and ammonium phosphate salts such as ammonium.

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. When the liquid medium contains the reducing agent, it is possible to effectively suppress the deposition of manganese dioxide and the like derived from the manganese contained in the fluoride particles. The reducing agent contained in the liquid medium should be capable of reducing, for example, tetravalent manganese ions eluted from fluoride into the liquid medium, and examples thereof include hydrogen peroxide, oxalic acid, and hydroxylamine hydrochloride. . Among these, hydrogen peroxide is preferable because it decomposes into water and does not adversely affect fluoride.

When the liquid medium contains a reducing agent, it may be prepared by dissolving a compound serving as the reducing agent in the liquid medium, or by mixing a solution containing the reducing agent with the liquid medium. Although the content of the reducing agent in the liquid medium is not particularly limited, it is, for example, 0.1% by mass or more, preferably 0.3% by mass or more, for the reason described above.

In addition to Sc and Y, rare earth elements that become rare earth ions to be brought into contact with phosphate ions include La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and A lanthanoid composed of Lu can be mentioned, and at least one selected from the lanthanoids is preferable, and at least one selected from the group consisting of La, Ce, Dy and Gd is more preferable.

The contact between the phosphate ions and the rare earth ions in the liquid medium may be carried out, for example, by dissolving a compound serving as a rare earth ion source in the liquid medium containing the phosphate ions. It may be performed by mixing with a solution containing ions. A solution containing rare earth ions can be prepared, for example, by dissolving a compound serving as a rare earth ion source in a solvent such as water. A compound that serves as a rare earth ion source is, for example, a metal salt containing a rare earth element, and examples of anions constituting the metal salt include nitrate ion, sulfate ion, acetate ion, chloride ion, and the like.

Contacting phosphate ions and rare earth ions in a liquid medium includes, for example, mixing a liquid medium containing phosphate ions and preferably further containing a reducing agent and fluoride particles to obtain a phosphor slurry; mixing with a body slurry and a solution containing rare earth ions.

The content of rare earth ions in the liquid medium in which phosphate ions and rare earth ions are brought into contact is, for example, 0.05% by mass or more or 0.1% by mass or more, and for example, 3% by mass or less or 2% by mass or less. be. Also, the content of rare earth ions relative to the amount of fluoride particles in the liquid medium is, for example, 0.2% by mass or more, or 0.5% by mass or more, and is, for example, 30% by mass or less, or 20% by mass or less. When the rare earth ion concentration is equal to or higher than the above lower limit, the adhesion rate of the rare earth phosphate to the fluoride particles tends to be further improved. tends to be easier to deposit more uniformly on the fluoride particle surfaces.

The contact temperature between the phosphate ions and the rare earth ions forming the rare earth phosphate 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. Contact may be performed while stirring the liquid medium

After the adhesion step, a separation step may be provided to separate the fluoride particles to which the rare earth phosphate is adhered from the liquid medium. Separation can be performed by solid-liquid separation means such as filtration and centrifugation. The phosphor obtained by solid-liquid separation may be subjected to washing treatment, drying treatment, or the like, if necessary.

The method for producing a fluoride phosphor further includes, after the synthesis step, a step of recovering the fluoride phosphor obtained in the synthesis step by solid-liquid separation, a step of drying the solid-liquid separated fluoride phosphor, and the like. You can

The method for producing a fluoride phosphor may include a surface treatment step of treating the fluoride phosphor obtained in the synthesis step with a coupling agent. After covering the fluoride particles with an oxide derived from a metal alkoxide, it may further include performing a silane coupling treatment. In the surface treatment step, a surface treatment layer containing functional groups derived from the coupling agent can be provided on the surface of the fluoride phosphor by bringing the fluoride phosphor and the coupling agent into contact with each other. This improves, for example, the moisture resistance of the fluoride phosphor.

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

Light-Emitting Device The light-emitting device includes a first phosphor containing the fluoride phosphor, a fluorescent member containing a resin, and a light-emitting element having an emission peak wavelength in a wavelength range of 380 nm or more and 485 nm or less. The light-emitting device may further include other components as necessary.

An example of a light-emitting device will be described with reference to the drawings. FIG. 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 having an emission peak wavelength on the short wavelength side of visible light (for example, in the range of 380 nm to 485 nm), and a molded body 40 on which the light-emitting element 10 is mounted. A body 40 has a first lead 20 and a second lead 30, and is integrally molded of thermoplastic resin or thermosetting resin. A light emitting element 10 is mounted on the bottom surface of the recess, and the light emitting element 10 has a pair of positive and negative electrodes, and the pair of positive and negative electrodes are a first lead 20 and a second lead 30 . They are electrically connected via a wire 60. The light emitting element 10 is sealed with a fluorescent member 50. The fluorescent member 50 is a fluorescent material including a fluoride fluorescent material that converts the wavelength of the light from the light emitting element 10. 70. The phosphor 70 emits light having an emission peak wavelength in a wavelength range different from that of the fluoride phosphor by excitation light from the first phosphor containing the fluoride phosphor and the light emitting element 10. A second phosphor that emits light may be included.

The fluorescent member may contain a resin and a fluorescent substance. Examples of resins constituting the fluorescent member include silicone resins, epoxy resins, modified silicone resins, modified epoxy resins, and acrylic resins. For example, the refractive index of the silicone resin may range from 1.35 to 1.55, more preferably from 1.38 to 1.43. If the refractive index of the silicone resin is within these ranges, it is excellent in translucency, and can be suitably used as the resin constituting the fluorescent member. Here, the refractive index of the silicone resin is the refractive index after curing, and is measured according to JIS K7142:2008. The fluorescent member may further contain a light diffusing material in addition to the resin and the fluorescent substance. By containing the light diffusing material, the directivity from the light emitting element can be relaxed and the viewing angle can be increased. Examples of light diffusing materials include silicon oxide, titanium oxide, zinc oxide, zirconium oxide, and aluminum oxide.

The light emitting element emits light having an emission peak wavelength in a wavelength range of 380 nm or more and 485 nm or less, which is a short wavelength region of visible light. The light emitting element may be an excitation light source that excites the fluoride phosphor. The light-emitting element preferably has an emission peak wavelength in the range of 380 nm or more and 480 nm or less, more preferably 410 nm or more and 480 nm or less, and more preferably 430 nm or more and 480 nm or less. It is further preferred to have A semiconductor light-emitting element is preferably used as the light-emitting element as the excitation light source. By using a semiconductor light-emitting element as an excitation light source, it is possible to obtain a stable light-emitting device with high efficiency, high output linearity with respect to input, and resistance to mechanical impact. As the semiconductor light emitting device, for example, a semiconductor light emitting device using a nitride semiconductor can be used. The half width of the emission peak in the emission spectrum of the light emitting element is preferably, for example, 30 nm or less.

The light emitting device comprises a first phosphor containing a fluoride phosphor. The details of the fluoride phosphor contained in the light emitting device are as described above. A fluoride phosphor is contained, for example, in a fluorescent member that covers the excitation light source. In a light-emitting device whose excitation light source is covered with a fluorescent member containing a fluoride phosphor, part 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 having an emission peak wavelength in the range of 380 nm or more and 485 nm or less, the radiated light can be used more effectively, and the loss of light emitted from the light emitting device can be reduced. and a highly efficient light emitting device can be provided.

Preferably, the light emitting device further includes a second phosphor including a phosphor other than the fluoride phosphor, in addition to the first phosphor including the fluoride phosphor. Any phosphor other than the fluoride phosphor may be used as long as it absorbs light from the light source and converts the wavelength into light of a wavelength different from that of the fluoride phosphor. The second phosphor can be contained in the fluorescent member, for example, in the same manner as the first phosphor.

The second phosphor may have an emission peak wavelength in a wavelength range of 495 nm or more and 590 nm or less, and is preferably a β-sialon phosphor, a halosilicate phosphor, a silicate phosphor, a rare earth aluminate phosphor, or a perovskite-based luminescence. It may be at least one selected from the group consisting of materials and nitride phosphors. The β-sialon phosphor may have, for example, a composition represented by the following formula (IIa). The halosilicate phosphor may have, for example, a composition represented by formula (IIb) below. The silicate phosphor may have, for example, a composition represented by formula (IIc) below. The rare earth aluminate phosphor may have a composition represented by the following formula (IId). The perovskite-based light-emitting material may have, for example, a composition represented by the following formula (IIe). The nitride phosphor may have a composition represented by, for example, formula (IIf), (IIg) or (IIh) below. Since the fluorescent member contains a β-sialon fluorescent substance or a perovskite-based light-emitting material as a second fluorescent substance other than a fluoride fluorescent substance, when the light-emitting device is used as, for example, a light source for a backlight, the range of color reproducibility is reduced. It can be a wider light-emitting device. The fluorescent member contains a halosilicate fluorescent substance, a silicate fluorescent substance, a rare earth aluminate fluorescent substance or a nitride fluorescent substance as a second fluorescent substance other than the fluoride fluorescent substance, so that the light emitting device can be used as a light source for illumination, for example. In that case, the light-emitting device can have higher color rendering properties or higher emission efficiency.

Si6 _{- tAltOtN8 -t} :Eu ₍ IIa)
(In formula (IIa), t is a number that satisfies 0<t≤4.2.)
_{(Ca,Sr,Ba)8MgSi4O16 ( F} ,Cl,Br) ₂ :Eu (IIb)
(Ba, Sr, Ca, Mg) ₂ SiO ₄ :Eu (IIc)
(Y, Lu, Gd, Tb) ₃ (Al, Ga) ₅ O ₁₂ :Ce (IId)
CsPb(F,Cl,Br,I) ₃ (IIe)
(La, Y, Gd) ₃ Si ₆ N ₁₁ :Ce (IIf)
(Sr, Ca) LiAl ₃ N ₄ :Eu (IIg)
(Ca,Sr) _AlSiN3 :Eu(IIh)

In this specification, in the formulas representing the composition of the phosphor or light-emitting material, the plurality of elements described separated by commas (,) means that at least one of these elements is included in the composition. means to contain Further, in the formulas representing the composition of the phosphor, before the colon (:) represents the host crystal, and after the colon (:) represents the activating element.

The average particle diameter of the second phosphor may 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. Also, the average particle size may preferably be 5 μm or less, or 3 μm or less. The average particle size of the second phosphor is measured by the FSSS method. The fluorescent member may contain the second phosphor singly or in combination of two or more.

The fluorescent member may further contain at least one kind of quantum dots in addition to the first fluorescent material. The quantum dot may absorb light from the light source and convert the wavelength into light with a wavelength different from that of the first phosphor, or may convert the wavelength into light with a similar wavelength. As quantum dots, perovskite having a composition such as (Cs, FA, MA) (Pb, Sn) (Cl, Br, I) ₃ (wherein FA means formamidinium and MA means methylammonium) Quantum dots having a structure, quantum dots having a chalcopyrite structure having a composition such as (Ag, Cu, Au) (In, Ga) (S, Se, Te) ₂ , (Cd, Zn) (Se, S), etc. and InP-based semiconductor quantum dots, etc., and may contain at least one selected from the group consisting of these. Here, in the formula representing the composition of the quantum dots, the multiple elements or cations described separated by commas (,) contain at least one of these multiple elements or cations in the composition. means

The invention according to the present disclosure includes the following aspects.
[1] A fluoride phosphor containing fluoride particles and an oxide covering at least part of the surface of the fluoride particles, wherein the oxide is Si, Al, Ti, Zr, Sn and Zn containing at least one selected from the group consisting of, the content of the oxide is 2% by mass or more and 30% by mass or less with respect to the fluoride phosphor, and the fluoride particles include a Group 4 element, When an element M containing at least one selected from the group consisting of Group 13 elements and Group 14 elements, an alkali metal, Mn, and F, and the number of moles of the alkali metal is 2 , the number of moles of Mn is more than 0 and less than 0.2, the number of moles of the element M is more than 0.8 and less than 1, and the number of moles of F is more than 5 and less than 7. Fluoride phosphor.

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

[3] The fluoride phosphor according to [1] or [2], wherein the fluoride particles have a composition represented by the following formula (1).
A ¹ _c [M ¹ _1-b Mn _b F _d ] (1)
(In formula (1), A ¹ contains at least one selected from the group consisting of Li, Na, K, Rb and Cs. M ¹ contains at least one of Si and Ge, Group 4 and at least one element selected from the group consisting of the elements of Group 14. b satisfies 0<b<0.2, and c is the [M ² _1-b Mn _b F _d ] ion is the absolute value of the charge of , and d satisfies 5<d<7.)

[4] The fluoride particles contain Si and Al as elements M in their composition, and the total number of moles of Si, Al and Mn is 0.9 or more when the number of moles of the alkali metal is 2.1. 1 or less, and the number of moles of Al is more than 0 and 0.1 or less, the fluoride phosphor according to [1].

[5] The fluoride phosphor according to [1] or [4], wherein the fluoride particles have a composition represented by the following formula (2).
A ² _f [M ² _1-e Mn _e F _g ] (2)
(In formula (2), A ² contains at least one selected from the group consisting of Li, Na, K, Rb and Cs. M ² contains at least Si and Al, a group 4 element, a It may further contain at least one element selected from the group consisting of elements of Group 13 and elements of Group 14. e satisfies 0<e<0.2, and f is [M ² _1-e Mn _e F _g ] is the absolute value of the charge of the ion, and g satisfies 5<g<7.)

[6] The fluoride phosphor according to any one of [1] to [5], wherein the oxide contains silicon.

[7] The fluoride phosphor according to any one of [1] to [6], wherein the oxide has an average thickness of 0.1 μm or more and 1.8 μm or less.

[8] In a fluorescent X-ray elemental analysis method, the ratio of the peak intensity of the Kα ray of the F element in the fluoride phosphor to the peak intensity of the Kα ray of the F element in the fluoride particles is 80% or less [1 ] The fluoride phosphor according to any one of [7].

[9] The fluoride particles have, on their surfaces, a rare earth phosphate containing at least one rare earth element selected from the group consisting of La, Ce, Dy and Gd, and the oxide is the rare earth phosphorus. The fluoride phosphor according to any one of [1] to [8], wherein the fluoride particles are coated via an acid salt.

[10] The fluoride phosphor according to [9], wherein the rare earth phosphate contains lanthanum.

[11] The fluoride phosphor according to [9] or [10], wherein the content of the rare earth phosphate is 0.1% by mass or more and 20% by mass or less as the content of the rare earth element.

[12] A method for producing a fluoride phosphor, comprising an element M containing at least one selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, an alkali metal, and Mn , and F, where the number of moles of the alkali metal is 2, the number of moles of Mn is more than 0 and less than 0.2, and the number of moles of the element M is more than 0.8 and less than 1 and providing fluoride particles having a composition in which the number of moles of F is greater than 5 and less than 7;
Derived from the metal alkoxide by contacting the prepared fluoride particles with a metal alkoxide containing at least one selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn in a liquid medium and covering at least part of the surface of the fluoride particles with an oxide in an amount of 2% by mass or more and 30% by mass or less with respect to the fluoride phosphor.

[13] A method for producing a fluoride phosphor, comprising an element M containing at least one selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, an alkali metal, and Mn , and F, where the number of moles of the alkali metal is 2, the number of moles of Mn is more than 0 and less than 0.2, and the number of moles of the element M is more than 0.8 and less than 1 and providing fluoride particles having a composition in which the number of moles of F is greater than 5 and less than 7;
In a liquid medium, the prepared fluoride particles, rare earth ions containing at least one selected from the group consisting of La, Ce, Dy and Gd, and phosphate ions are brought into contact to form a rare earth phosphate. obtaining attached fluoride particles;
By contacting the fluoride particles to which the rare earth phosphate is attached and a metal alkoxide containing at least one selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn in a liquid medium, the an oxide derived from a metal alkoxide covering at least a portion of the surface of the fluoride particles to which the rare earth phosphate is attached in an amount of 2% by mass or more and 30% by mass or less relative to the fluoride phosphor; Manufacturing method including.

[14] The prepared fluoride particles contain at least one of Si and Ge as the element M in their composition, and when the number of moles of the alkali metal is 2, the total number of moles of Si, Ge and Mn is 0. .The production method according to [12] or [13], which is 9 or more and 1.1 or less.

[15] The production method according to [14], wherein the prepared fluoride particles have a composition represented by the following formula (1).
A ¹ _c [M ¹ _1-b Mn _b F _d ] (1)
(In formula (1), A ¹ contains at least one selected from the group consisting of Li, Na, K, Rb and Cs. M ¹ contains at least one of Si and Ge, Group 4 and at least one element selected from the group consisting of the elements of Group 14. b satisfies 0<b<0.2, and c is the [M ² _1-b Mn _b F _d ] ion is the absolute value of the charge of , and d satisfies 5<d<7.)

[16] The prepared fluoride particles contain Si and Al as elements M in their composition, and when the number of moles of the alkali metal is 2, the total number of moles of Si, Al, and Mn is 0.9 or more. 1.1 or less, and the number of moles of Al is more than 0 and 0.1 or less, [12] or [13].

[17] The production method according to [16], wherein the prepared fluoride particles have a composition represented by the following formula (2).
A ² _f [M ² _1-e Mn _e F _g ] (2)
(In formula (2), A ² contains at least one selected from the group consisting of Li, Na, K, Rb and Cs. M ² contains at least Si and Al, a group 4 element, a It may further contain at least one element selected from the group consisting of elements of Group 13 and elements of Group 14. e satisfies 0<e<0.2, and f is [M ² _1-e Mn _e F _g ] is the absolute value of the charge of the ion, and g satisfies 5<g<7.)

[18] The production according to any one of [12] to [17], further comprising covering at least part of the surface of the fluoride particles with an oxide derived from the metal alkoxide, and then performing a silane coupling treatment. Method.

[19] Any one of [12] to [18], wherein the metal alkoxide contacted in the liquid medium contains at least one selected from the group consisting of tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane. Method of manufacture as described.

[20] A light-emitting device comprising a fluorescent member containing the fluoride phosphor according to any one of [1] to [11] and a resin, and a light-emitting element having an emission peak wavelength in a wavelength range of 380 nm or more and 485 nm or less. .

EXAMPLES The present invention will be specifically described below by way of examples, but the present invention is not limited to these examples.

Production example 1
A phosphor having a Mn content of 1.5% by mass and a first theoretical composition represented by K ₂ SiF ₆ :Mn (hereinafter sometimes abbreviated as “KSF”) by the above-described method Fluoride particles A1 were obtained.

Production example 2
According to the above method, the Mn content is 1.5% by mass, and the second theoretical composition represented by K ₂ Si _0.99 Al _0.01 F _5.99 :Mn (hereinafter abbreviated as “KSAF” Fluoride particles A2, which are phosphors having

Production example 3
To 150.0 g of an aqueous sodium salt solution of phosphoric acid (phosphoric acid concentration: 2.4% by mass), 15.0 g of 35% by mass hydrogen peroxide solution and 735.0 g of pure water were added, and 300 g of the fluoride particles A1 produced in Production Example 1 were added while stirring at several 400 rpm and then at room temperature to prepare a phosphor slurry.

Next, a lanthanum nitrate aqueous solution (lanthanum concentration: 5.0% by mass) prepared by dissolving 23.4 g of lanthanum nitrate dihydrate in 156.6 g of pure water was dropped into the phosphor slurry over about 1 minute. After about 30 minutes from the completion of dropping, stirring was stopped and the mixture was allowed to stand. The obtained precipitate was subjected to solid-liquid separation, washed with ethanol, and dried at 90° C. for 10 hours to prepare fluoride particles A3 of Production Example 3 having lanthanum phosphate arranged on the surface.

Production example 4
Fluoride particles A4 of Production Example 4 having lanthanum phosphate arranged on the surface thereof were produced in the same manner as in Production Example 3, except that the fluoride particles A2 produced in Production Example 2 were used.

Production example 5
Fluoride, which is a phosphor having a Mn content of 1.0% by mass and a second theoretical composition represented by K ₂ Si _0.99 Al _0.01 F _5.99 :Mn by the above method Particles A5 were obtained.

Production example 6
Fluoride particles A6 of Production Example 6 having lanthanum phosphate arranged on the surface thereof were produced in the same manner as in Production Example 3 except that the fluoride particles A5 produced in Production Example 5 were used.

Production example 7
After obtaining a phosphor having a Mn content of 1.2% by mass and a second theoretical composition represented by K ₂ Si _0.99 Al _0.01 F _5.99 :Mn by the above method Fluoride particles A7 of Production Example 7 having lanthanum phosphate arranged on the surface thereof were produced in the same manner as in Production Example 3.

Example 1
300 g of the fluoride particles A1 produced in Production Example 1 were weighed, added to a mixed solution of 540 ml of ethanol, 130.2 ml of ammonia water containing 16.5% by mass of ammonia, and 60 ml of pure water, and stirred. While stirring at a rotation speed of 400 rpm using a blade, the liquid temperature was kept at room temperature to obtain a reaction mother liquid. 32.1 g of tetraethoxysilane (TEOS: Si(OC ₂ H ₅ ) ₄ ) was weighed and added dropwise to the stirring reaction mother liquor over about 3 hours. After that, stirring was continued for 1 hour, and after adding 10 g of 35% by mass hydrogen peroxide (H ₂ O ₂ ), the 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 covered with silicon dioxide (SiO ₂ ). The amount of tetraethoxysilane dropped was about 3% by mass in terms of silicon dioxide with respect to the fluoride particles.

Example 2
A fluoride phosphor E2 of Example 2 was produced in the same manner as in Example 1, except that the amount of tetraethoxysilane added was 107.1 g. The amount of tetraethoxysilane dropped was about 10% by mass in terms of silicon dioxide with respect to the fluoride particles.

A backscattered electron image of the fluoride phosphor obtained in Example 2 observed with a scanning electron microscope is shown in FIG. The relatively many gray areas observed in FIG. 2 correspond to the silicon dioxide films, and the slightly darker gray areas seen in the mesh between them indicate that part of the surface of the fluoride particles is exposed. handle. As shown in FIG. 2, in the fluoride phosphor, most of the surfaces of the fluoride particles are covered with silicon dioxide. It can be seen that the form of silicon dioxide covering the fluoride particles is not particles but a continuous film. It is believed that direct contact between the fluoride particles and the resin is effectively suppressed by the film-like covering of the fluoride particles by the silicon dioxide. Also, cracks (slightly darker gray areas) are present in part of the silicon dioxide film. It is considered that the fewer these cracks, the more effectively the direct contact between the fluoride particles and the resin can be suppressed.

Example 3
A fluoride phosphor E3 of Example 3 was produced in the same manner as in Example 1, except that the amount of tetraethoxysilane dropped was 214.2 g. The amount of tetraethoxysilane dropped was about 20% by mass in terms of silicon dioxide with respect to the fluoride particles.

Example 4
The fluoride phosphor of Example 4 was produced in the same manner as in Example 1 except that the fluoride particles A2 produced in Production Example 2 were used, the stirring speed was 500 rpm, and the amount of tetraethoxysilane dropped was 107.1 g. E4 was made.

Example 5
100 g of fluoride particles A3 produced in Production Example 3 were weighed, 180 ml of ethanol, 43.4 ml of ammonia water containing 16.5% by mass of ammonia, 20 ml of pure water, and a rotation speed using a stirring blade of 300 rpm. A fluoride phosphor E5 of Example 5 was produced in the same manner as in Example 1, except that 35.7 g of tetraethoxysilane was added dropwise in 6 hours.

Example 6
100 g of the fluoride particles A3 produced in Production Example 3 were weighed, added to a mixed solution of 139 ml of ethanol and 35.7 ml of pure water, and stirred at a rotation speed of 300 rpm using a stirring blade. was kept at room temperature and used as the reaction mother liquor. 35.7 g of tetraethoxysilane was weighed as A solution, and 42.9 g of ammonia water containing 16.5% by mass of ammonia was weighed as B solution. After the liquids A and B were added dropwise to the stirring reaction mother liquor over about 3 hours, the mixture was stirred for 1 hour, and 10 g of 35% by mass hydrogen peroxide (H ₂ O ₂ ) was further added, and then the 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 a fluoride phosphor E6 of Example 6.

Example 7
First, 50 g of the fluoride phosphor E6 produced in Example 6 was weighed. Next, 84.9 ml of ethanol, 5.8 ml of pure water, and decyltrimethoxysilane ((CH ₃ O) ₃ Si(CH ₂ ) ₉ CH ₃ )) as a silane coupling agent were mixed. After stirring for 20 minutes, the mixture was allowed to stand for 20 hours or more. The fluoride phosphor E6 produced in Example 6 was added to this solution, and after stirring at 200 rpm for 1 hour, the stirring was stopped. After solid-liquid separation of the resulting precipitate, the precipitate was dried at 105° C. for 10 hours for silane coupling treatment to obtain a fluoride phosphor E7.

Example 8
A fluoride phosphor E8 of Example 8 was produced in the same manner as in Example 4, except that the fluoride particles A4 produced in Production Example 4 were used.

Example 9
Fluoride phosphor E9 of Example 9 was produced in the same manner as in Example 7 except that the fluoride phosphor E8 produced in Example 8 was used.

Example 10
Fluoride phosphor E10 of Example 10 was produced in the same manner as in Example 2 except that the fluoride particles A5 produced in Production Example 5 were used, the stirring speed was 350 rpm, and the dropping time of tetraethoxysilane was 6 hours. was made.

Example 11
A fluoride phosphor E11 of Example 11 was produced in the same manner as in Example 10 except that the fluoride particles A6 produced in Production Example 6 were used.

Example 12
A fluoride phosphor E12 of Example 12 was produced in the same manner as in Example 7 except that the fluoride phosphor E11 produced in Example 11 was used.

Example 13
A fluoride phosphor E13 of Example 13 was obtained in the same manner as in Example 10, except that the amount of tetraethoxysilane dropped was 64.3 g.

Example 14
A fluoride phosphor E14 of Example 14 was obtained in the same manner as in Example 10, except that the amount of tetraethoxysilane added was 32.2 g.

Example 15
A fluoride phosphor was obtained in the same manner as in Example 13, except that the fluoride particles A7 produced in Production Example 7 were used. The obtained phosphor was subjected to silane coupling treatment in the same manner as in Example 7 except that hexyltrimethoxysilane was used as the silane coupling agent, to obtain fluoride phosphor E15 of Example 15. .

Example 16
A fluoride phosphor E16 of Example 16 was obtained in the same manner as in Example 15 except that vinyltrimethoxysilane was used as the silane coupling agent.

Example 17
A fluoride phosphor E17 of Example 17 was obtained in the same manner as in Example 15 except that 3-aminopropyltriethoxysilane was used as the silane coupling agent.

Example 18
A fluoride phosphor E18 of Example 18 was obtained in the same manner as in Example 15 except that 3-glycidoxypropyltrimethoxysilane was used as the silane coupling agent.

Reference example 1
The fluoride particles A1 obtained in Production Example 1 were used as the fluoride phosphor C1 of Reference Example 1.

Reference example 2
The fluoride particles A2 obtained in Production Example 2 were used as the fluoride phosphor C2 of Reference Example 2.

Reference example 3
The fluoride particles A3 obtained in Production Example 3 were used as the fluoride phosphor C3 of Reference Example 3.

Reference example 4
The fluoride particles A4 obtained in Production Example 4 were used as the fluoride phosphor C4 of Reference Example 4.

Reference example 5
The fluoride particles A6 obtained in Production Example 6 were used as the fluoride phosphor C5 of Reference Example 5.

Reference example 6
The fluoride particles A7 obtained in Production Example 7 were used as the fluoride phosphor C6 of Reference Example 6.

Evaluation (1) Amount of silicon dioxide For each fluoride phosphor obtained, composition analysis was performed by ICP emission spectrometry, and the analyzed Si concentration of the fluoride phosphor covered with silicon dioxide obtained in the example and the reference From the difference in the analyzed Si concentration of the fluoride phosphor of the example, the amount of silicon dioxide covering the fluoride particles was calculated, and the silicon dioxide content (SiO ₂ analysis value) relative to the fluoride phosphor was obtained. The results are shown in Tables 1, 2, 3 and 4.

(2) Fluorescent X-ray elemental analysis: XRF evaluation For each fluoride phosphor obtained above, an XRF device (product name: ZSX Primus II, manufactured by Rigaku Co., Ltd.) was used to perform a fluorescent X-ray elemental analysis (XRF: The peak intensity of the Kα line of the F element was measured by X-Ray Fluorescence spectrometry). The peak intensity ratios of the fluoride phosphors of Examples 1 to 3 were calculated as relative values with the peak intensity of the fluoride phosphor of Reference Example 1 being 100. Similarly, the peak intensity ratio of the fluoride phosphor of Example 4 was calculated as a relative value with the peak intensity of the fluoride particles of Reference Example 2 being 100. From the obtained peak intensity ratio, the average thickness of the silicon dioxide film in the fluoride phosphor of each example was calculated using the CXRO (The Center for X-Ray Optics) database. Table 1 shows the results.

(3) Scanning Electron Microscope Observation Image observation of the obtained fluoride phosphors of Examples 6 and 8 was performed using a scanning electron microscope (SEM). SEM images are shown in FIGS. Furthermore, for the fluoride phosphors of Examples 6 and 8, an arbitrary cross section was observed using a scanning electron microscope (SEM), and the average thickness of the silicon dioxide film was measured by image analysis. Specifically, a plurality of fluoride phosphor particles were embedded in a resin, a cross-sectional sample was prepared by ion milling, and a cross-sectional observation of the fluoride phosphor particles was made possible with a scanning electron microscope. Cross-sectional SEM images are shown in FIGS.

Regarding the obtained cross-sectional SEM image, the thickness of the silicon dioxide film was measured at five locations per one fluoride phosphor particle, and the measured average thickness was calculated as the arithmetic mean of the thicknesses at a total of 25 locations for the five particles. However, the thickness of the silicon dioxide film here means the thickness of the film that can be seen on the SEM image, including the portion where the film is cut obliquely to the thickness direction. Table 2 shows the results.

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

(5) Lanthanum content For the obtained fluoride phosphors of Examples 5 to 9 and 11 to 18 and Reference Examples 3 to 6, the lanthanum content was analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). to determine the content (La analysis value) with respect to the fluoride particles. The results are shown in Tables 2 and 4.

(6) Manganese content The manganese content of the obtained fluoride phosphors of Examples 10 to 18 and Reference Examples 1, 3, 5 and 6 was analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Then, the content ratio (Mn analysis value) with respect to the fluoride phosphor was obtained. Tables 3 and 4 show the results.

(7) Evaluation of change in mass of resin composition The effect of the fluoride phosphor on the change in mass of the resin composition containing the resin and the fluoride phosphor was evaluated as follows. A resin composition was prepared by mixing a silicone resin with 33% by mass of a fluoride phosphor relative to the silicone resin. About 1 g of the obtained resin composition was weighed onto an aluminum foil and cured, and then the difference between the mass of the cured resin composition and the mass of the aluminum foil was calculated and used as the initial value. The resin composition cured on the aluminum foil was left to stand in a small oven (product name: constant temperature and humidity chamber LH-114, manufactured by Espec Co., Ltd.) maintained at 200 ° C. After 100 hours, 300 hours, and 500 hours. , and the mass after 1000 hours were measured. Taking the initial value as 100%, the mass retention rate (%) of the resin composition after each time was calculated. A higher mass retention rate indicates that the reaction between the fluoride phosphor and the resin is more suppressed, which means that the durability of the resin composition is superior. For the evaluation, silicone resins selected from commercially available silicone resins were used. Specifically, for Examples 1 to 9 and Reference Examples 1 to 4, Shin-Etsu Chemical Co., Ltd. dimethyl silicone resin (product name KER-2936; refractive index 1.41, hereinafter referred to as "dimethyl silicone resin 1" ) was used for evaluation. Further, for Examples 10 and 11 and Reference Example 1, Dow Corning Toray Co., Ltd. dimethyl silicone resin (trade name OE-6351; refractive index 1.41, hereinafter referred to as "dimethyl silicone resin 2"), Toray・ Phenyl silicone resin manufactured by Dow Corning Co., Ltd. (trade name OE-6630; refractive index 1.53, hereinafter referred to as “phenyl silicone resin 1”) and a phenyl silicone resin having a different refractive index from the above phenyl silicone resin 1 (refractive ratio 1.50, hereinafter referred to as "phenyl silicone resin 2").

(8) Evaluation of Durability Durability of each fluoride phosphor obtained above was evaluated as follows. For each fluoride phosphor, the internal quantum efficiency with respect to excitation light of 450 nm was measured using a quantum efficiency measurement device (product name: QE-2000, manufactured by Otsuka Electronics Co., Ltd.), and used as initial characteristics. Next, the fluoride particles or the fluoride phosphor were placed in a glass petri dish and allowed to stand for 100 hours in a small high-temperature, high-humidity bath (manufactured by Espec Co., Ltd.) maintained at a temperature of 85° C. and a relative humidity of 85%. After that, the internal quantum efficiency of each fluoride phosphor was measured by the same method, and the quantum efficiency retention rate (%) was calculated when the initial characteristics were assumed to be 100%. A higher quantum efficiency retention rate means better durability. Tables 1 to 5 show the results.

Production Example 1 of Light Emitting Device
The fluoride phosphors of Examples 1 to 9 and Reference Examples 1 to 4 were used as first phosphors. A β-sialon phosphor having a composition represented by Si _5.81 Al _0.19 O _0.19 N _7.81 :Eu and having an emission peak wavelength near 540 nm was used as the second phosphor. A phosphor 70 containing a first phosphor 71 and a second phosphor 72 is mixed with a silicone resin such that x is 0.280 and y is around 0.270 in the CIE 1931 color system. A resin composition was obtained. Next, a molded body 40 having a concave portion is prepared, and a light emitting element 10 made of a gallium nitride-based compound semiconductor having an emission peak wavelength of 451 nm is placed on the first lead 20 on the bottom surface of the concave portion. The ten electrodes, the first lead 20 and the second lead 30 were connected with wires 60, respectively. Further, a resin composition was injected into the concave portion of the molded body 40 using a syringe so as to cover the light emitting element 10 , and the resin composition was cured to form a fluorescent member, thereby manufacturing the light emitting device 1 .

Production Example 2 of Light Emitting Device
The fluoride phosphors of Examples 10 to 18 and Reference Examples 3, 5 and 6 were used as first phosphors. A rare earth aluminate phosphor having a composition represented by Lu ₃ Al ₅ O ₁₁ :Ce as a second phosphor and having an emission peak near 530 nm, and a composition represented by Y ₃ Al ₅ O ₁₁ :Ce and a rare earth aluminate phosphor having an emission peak around 535 nm, and a nitride phosphor having a composition represented by (Ca, Sr)AlSiN ₃ :Eu and having an emission peak wavelength around 630 nm used in combination. A phosphor 70 containing a first phosphor 71 and a second phosphor 72 is mixed with a silicone resin such that x is 0.459 and y is around 0.411 in the CIE 1931 color system. A light-emitting device 2 was manufactured in the same manner as in Light-Emitting Device Manufacturing Example 1, except that the resin composition was obtained.

Durability evaluation 1
For the light emitting device 1 or 2 using each fluoride phosphor obtained in Examples 1 to 9 and 15 to 18 and Reference Examples 1 to 4 and 6, in an environmental tester at a temperature of 85 ° C. and a relative humidity of 85% Durability test 1 was performed after storing for 500 hours. The luminous flux maintenance factor 1 (%) of the light-emitting device 1 or 2 after the durability test 1 was obtained when the luminous flux of the light-emitting device 1 or 2 before the durability test 1 was taken as 100%. The higher the luminous flux maintenance factor 1, the better the durability against high heat and high humidity. The results are shown in Tables 1, 2 and 5.

Durability evaluation 2
For the light-emitting device 2 using each fluoride phosphor obtained in Examples 10 to 18 and Reference Examples 3, 5 and 6, in an unhumidified environmental tester at a temperature of 85 ° C., a current value of 150 mA and 1000 A durability test 2 was performed by time-driving. The luminous flux maintenance factor 2 (%) of the light-emitting device 2 after the durability test 2 was obtained when the luminous flux of the light-emitting device 2 before the durability test 2 was taken as 100%. The higher the luminous flux maintenance factor 2, the better the durability against high heat. The results are shown in Tables 4 and 5.

The SiO ₂ analysis values of the fluoride phosphors of Examples 1 to 4 increased with increasing SiO ₂ loading. The peak intensity ratios of the Kα rays of the F element by XRF in the fluoride phosphors of Examples were all reduced to 80% or less of the peak intensity of the fluoride phosphors of Reference Examples 1 and 2. From this, it is considered that the Kα ray of the F element is absorbed by the SiO ₂ film, and the SiO ₂ is considered to cover the surface of the fluoride particles as a film. The film thickness was calculated to be 0.13 μm or more from each absorptance.

The fluoride phosphors of Examples 1 to 3 had higher quantum efficiency retention rates than the fluoride phosphor of Reference Example 1. Further, compared to the resin composition containing the fluoride phosphor of Reference Example 1, the resin compositions containing the fluoride phosphors of Examples 1 to 3 have a higher mass retention rate, and the durability of the resin composition is excellent. was Regarding the durability of the resin composition, in comparison with Example 1, in which the average thickness of the _SiO film is thin, in Examples 2 and 3, in which the average thickness is thick, the mass retention rate of the resin composition after 500 hours is further improved. It can be seen that the durability of the resin composition is further improved. Compared to Reference Example 2 in which the composition of the fluoride particles was changed, the fluoride phosphor of Example 4 coated with a _SiO2 film with the same composition had a high quantum efficiency maintenance rate in the durability evaluation, and the resin composition Mass retention rate is also high. That is, similar effects were obtained with fluoride particles having KSAF in their composition.

Compared to the light-emitting device 1 using the fluoride phosphor of Reference Example 1, the light-emitting devices 1 using the fluoride phosphors of Examples 1 to 3 had a higher luminous flux maintenance factor 1 and were excellent in durability. From this, it can be seen that even in the light emitting device 1, the use of the fluoride phosphor coated with the SiO ₂ film exhibits 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 exhibited improved durability. A similar effect was obtained. Comparing the light emitting device 1 using the fluoride phosphor of Example 2 and the light emitting device 1 using the fluoride phosphor of Example 4, the light emitting device 1 using the fluoride phosphor having KSAF in the composition is compared. Luminous flux maintenance factor 1 of the light emitting device 1 using the fluoride phosphor was 1% higher than that of the light emitting device 1 using the fluoride phosphor of Example 2 using the fluoride phosphor having KSF in its composition. .

A SEM image of the fluoride phosphor obtained in Example 6 observed with a scanning electron microscope is shown in FIG. It can be seen from FIG. 4 that the surface of the fluoride phosphor is smooth, and the form of silicon dioxide covering the fluoride particles is not particles but a continuous film. FIG. 6 shows an SEM image of the fluoride phosphor obtained in Example 8 observed with a scanning electron microscope. From FIG. 6, it can be seen that the form of silicon dioxide covering the fluoride particles is not particles, but a continuous film even in the case of fluoride particles having KSAF in the composition.

FIG. 3 shows an image obtained by observing a cross section of the fluoride phosphor obtained in Example 6 with a scanning electron microscope. In FIG. 3 , the gray portion corresponds to fluoride particles 2 , the white portion corresponds to lanthanum phosphate 4 , and the dark gray portion corresponds to silicon dioxide 6 . From this, it can be seen that in the fluoride phosphor, lanthanum phosphate 4 adheres to fluoride particles 2 and is further covered with silicon dioxide 6 . Further, FIG. 5 shows an image of a cross section of the fluoride phosphor obtained in Example 8 observed with a scanning electron microscope. In FIG. 5 , the gray portion corresponds to fluoride particles 2 , the white portion corresponds to lanthanum phosphate 4 , and the dark gray portion corresponds to silicon dioxide 6 . From this, it can be seen that lanthanum phosphate 4 adheres to fluoride particles 2 and is further covered with silicon dioxide 6 .

The SiO ₂ analysis values of the fluoride phosphors of Examples 5 to 11 were comparable to those of Examples 2 and 4. The measured average thicknesses of _{the SiO} films measured by image analysis of the cross-sectional SEM images of the fluoride phosphors of Examples 6 and 8 shown in FIGS. It roughly agrees with the average film thickness calculated from the XRF of 2 and 4. From this, it was confirmed that the surface of the fluoride phosphor to which lanthanum phosphate was adhered was also covered with a SiO ₂ film having a similar thickness. Therefore, it is considered that SiO ₂ similarly covers the fluoride particles as a film even if the dropping method, the dropping time, and the number of stirring during the reaction are changed.

The TC analysis values of the fluoride phosphors of Examples 7 and 9 were higher than those of the fluoride phosphors of Reference Examples 3 and 4, confirming the presence of carbon. Since this carbon is considered to be derived from the silane coupling agent, by subjecting the fluoride phosphor covered with SiO ₂ to the silane coupling treatment, a component derived from the silane coupling agent is formed on the surface of the fluoride phosphor. It is considered to adhere.

The fluoride phosphors of Examples 5 to 7 had higher quantum efficiency retention rates than the fluoride phosphor of Reference Example 3. Further, in the fluoride phosphors of Examples 5 to 7, the mass retention rate of the resin composition was higher than that of the fluoride phosphor of Reference Example 3, and the durability of the resin composition was excellent. As for durability, compared with Example 6, Example 7, in which the silane coupling treatment was performed, has a higher quantum efficiency retention rate, indicating that the durability is further improved. This is probably because the surface of the SiO ₂ film was made hydrophobic by the silane coupling treatment. With respect to the fluoride phosphor in which lanthanum phosphate is attached to the fluoride particles having the second composition (KSAF) of Reference Example 4, the same composition (KSAF) of Example ₈ covered with a SiO film With the fluoride phosphor, both the quantum efficiency retention rate in the durability evaluation and the mass retention rate of the resin composition were high, and the fluoride phosphor and the resin composition were excellent in durability. As for durability, compared with Example 8, Example 9, in which the silane coupling treatment was performed, has a higher quantum efficiency retention rate, indicating that the durability is further improved. In the fluoride particles having the second composition (KSAF), the quantum efficiency maintenance rate is higher in Example 8 with lanthanum phosphate attached than in Example 4 with no lanthanum phosphate attached. A higher effect was obtained by covering the surface of the phosphor with lanthanum acid attached with SiO ₂ . That is, even in the fluoride phosphor to which lanthanum phosphate was adhered, the effect of improving the durability was obtained by covering it with the SiO ₂ film.

Compared to the light-emitting device 1 using the fluoride phosphor of Reference Example 3, the light-emitting devices 1 using the fluoride phosphors of Examples 5 to 7 had a high luminous flux maintenance factor 1 and excellent durability. It can be seen that the luminous flux maintenance factor 1 of the light emitting device 1 using the fluoride phosphor of Example 7, which was subjected to silane coupling treatment, was further improved, and the durability was further improved. There is a correlation between the quantum efficiency maintenance factor of the fluoride phosphor and the luminous flux maintenance factor 1 of the light emitting device 1, and the durability is improved by covering the fluoride phosphor with a _SiO2 film, and the durability is further enhanced by the silane coupling treatment. improvement effect was obtained. Compared to the light-emitting device 1 using the fluoride phosphor of Reference Example 4, the light-emitting device 1 using the fluoride particles of Examples 8 and 9 also showed improved durability, and the lanthanum phosphate was attached to the light-emitting device 1. Even with fluoride particles having a composition of 2 (KSAF), the effect of improving durability was obtained by covering with a SiO ₂ film.

Observation of the cross-section of the light-emitting device 1 confirmed the sedimentation state of the phosphor. It is believed that the silane coupling treatment improved the affinity with the resin, making it easier for the phosphor to settle.

The fluoride phosphors of Examples 10 and 11 had higher quantum efficiency retention rates than the fluoride particles of Reference Example 1. Further, compared with the fluoride particles of Reference Example 1, the fluoride phosphors of Examples 10 and 11 had a higher mass retention rate of the resin composition, and the durability of the resin composition was superior. In the phenyl silicone resins 1 and 2, even the fluoride particles of Reference Example 1 had a high mass retention rate, but Examples 10 and 11 had a higher mass retention rate. When the dimethyl silicone resins 1 and 2 were used, the mass retention rate of the fluoride particles of Reference Example 1 was greatly reduced, but in Examples 10 and 11, the mass retention rate was high. In particular, the mass retention rate of Example 11 was high, and a higher effect was obtained by covering the surface of the phosphor to which lanthanum phosphate was attached with a SiO ₂ film. In any resin, rather than the fluoride particles having KSF in the composition of Reference Example 1, Example 10 in which the fluoride particles having KSAF in the composition were covered with a _SiO film, and the phosphor to which lanthanum phosphate was attached The durability of the resin composition was superior in Example 11, in which the surface was covered with a SiO ₂ film.

The fluoride phosphors of Examples 11 to 14 had higher quantum efficiency retention rates than the fluoride phosphor of Reference Example 5. The mass retention rate of the resin composition was also increased, and the durability of the resin composition was excellent. The light-emitting devices 2 using the fluoride phosphors of Examples 10 to 14 had a higher luminous flux maintenance factor 2 than the light-emitting device 2 using the fluoride phosphor of Reference Example 5, and were superior in durability. The light-emitting devices 2 using fluoride phosphors of Examples 11 and 12 use fluoride phosphors in which the surface of the phosphor to which lanthanum phosphate is attached is covered with SiO ₂ . It was superior in durability to the light emitting device 2 using a fluoride phosphor. This is probably because lanthanum phosphate improves the adhesion of the silica coat and suppresses peeling of the coat layer. Furthermore, in the light-emitting device 2 using the fluoride phosphor of Example 12, the affinity with the resin is improved by the silane coupling treatment, so that the phosphor easily settles and the adhesion with the resin is also improved. Therefore, it is considered that a higher effect can be obtained. The light-emitting devices 2 using the fluoride phosphors of Examples 13 and 14 with a reduced SiO ₂ concentration were superior in durability to the light-emitting device 2 using the fluoride phosphor of Example 10. The reason for this is thought to be that by reducing the SiO ₂ concentration, cracking of the SiO ₂ film was suppressed, and contact with the external environment at the location of the crack was suppressed. The fluoride particles having the second composition (KSAF) of Examples 13 and 14 were covered with a SiO film rather than the light-emitting device 2 using the fluoride particles having the KSF composition to which _lanthanum phosphate was attached in Reference Example 3. Light emitting device 2 using a fluoride phosphor, and light emission using a fluoride phosphor in which fluoride particles having a second composition (KSAF) with lanthanum phosphate attached in Examples 11 and 12 were covered with a SiO ₂ film Apparatus 2 was superior in durability.

The fluoride phosphors of Examples 15 to 18 had higher quantum efficiency retention rates than the fluoride phosphor of Reference Example 6. The mass retention rate of the resin composition is also increased, the durability as a powder is excellent, and it is considered that the affinity with the resin is improved by the silane coupling treatment. In the durability evaluation 1, the light-emitting device 2 using the fluoride phosphors of Examples 15, 16 and 18 had a higher luminous flux maintenance factor 1 than the light-emitting device 2 using the fluoride phosphor of Reference Example 6. rice field. Furthermore, in the durability evaluation 2, the light emitting device 2 using the fluoride phosphor of Examples 15 to 18 had a higher luminous flux maintenance factor 2 than the light emitting device 2 using the fluoride phosphor of Reference Example 6. rice field. This factor can be considered, for example, as follows. In the silane coupling agent, the methoxy group or ethoxy group hydrolyzes to form a hydrogen bond with the —OH group on the surface of the phosphor, which is then chemically bonded by heating. Therefore, the silane coupling agent is difficult to bond to the fluoride particles of the first composition (KSF) and the second composition (KSAF), which have few —OH groups on the surface. On the other hand, it is thought that there are many —OH groups on the surface of the fluoride phosphor in which the fluoride particles are covered with SiO ₂ . , it is considered that the effects as described above were obtained. In particular, the fluoride phosphors of Examples 15 to 18 have a second composition in which the surface of the phosphor to which lanthanum phosphate is attached is covered with SiO ₂ . It is believed that this lanthanum phosphate improves the adhesion of the _SiO2 film and suppresses cracking and peeling of the coating layer, which facilitates uniform bonding of the silane coupling agent and improves affinity with the resin. be done.

The fluoride phosphor according to the present disclosure is particularly used in a light emitting device using a light emitting diode as an excitation light source, for example, a light source for illumination, a light source for LED display or liquid crystal backlight application, a traffic light, an illuminated switch, various sensors, It can be suitably used for various indicators, small stroboscopes, and the like.

2: Fluoride particles, 4: Lanthanum phosphate, 6: Silicon dioxide, 10: Light emitting element, 20: First lead, 30: Second lead, 40: Molded body, 50: Fluorescent member, 60: Wire, 70: Phosphor, 100: Light-emitting device.

Claims (20)

A fluoride phosphor containing fluoride particles and an oxide covering at least part of the surface of the fluoride particles,
The oxide contains at least one 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 with respect to the fluoride phosphor. % by mass or less,
The fluoride particles contain an element M containing at least one 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 number of moles of the alkali metal is 2, the number of moles of Mn is more than 0 and less than 0.2, the number of moles of the element M is more than 0.8 and less than 1, and the number of moles of F is A fluoride phosphor having a composition greater than 5 and less than 7. The fluoride particles contain at least one of Si and Ge as an element M in their composition, and the total number of moles of Si, Ge and Mn is 0.9 or more when the number of moles of the alkali metal is 2.1. 2. The fluoride phosphor according to claim 1, which is 1 or less. 2. The fluoride phosphor according to claim 1, wherein said fluoride particles have a composition represented by the following formula (1).
A ¹ _c [M ¹ _1-b Mn _b F _d ] (1)
(In formula (1), A ¹ contains at least one selected from the group consisting of Li, Na, K, Rb and Cs. M ¹ contains at least one of Si and Ge, Group 4 and at least one element selected from the group consisting of the elements of Group 14. b satisfies 0<b<0.2, and c is the [M ² _1-b Mn _b F _d ] ion is the absolute value of the charge of , and d satisfies 5<d<7.) The fluoride particles contain Si and Al as elements M in their composition, and when the number of moles of the alkali metal is 2, the total number of moles of Si, Al, and Mn is 0.9 or more and 1.1 or less. 2. The fluoride phosphor according to claim 1, wherein the number of moles of Al is more than 0 and 0.1 or less. 2. The fluoride phosphor according to claim 1, wherein said fluoride particles have a composition represented by the following formula (2).
A ² _f [M ² _1-e Mn _e F _g ] (2)
(In formula (2), A ² contains at least one selected from the group consisting of Li, Na, K, Rb and Cs. M ² contains at least Si and Al, a group 4 element, a It may further contain at least one element selected from the group consisting of elements of Group 13 and elements of Group 14. e satisfies 0<e<0.2, and f is [M ² _1-e Mn _e F _g ] is the absolute value of the charge of the ion, and g satisfies 5<g<7.) 6. The fluoride phosphor according to any one of claims 1 to 5, wherein said oxide contains silicon. The fluoride phosphor according to any one of claims 1 to 5, wherein the oxide has an average thickness of 0.1 µm or more and 1.8 µm or less. 6. In fluorescent X-ray elemental analysis, the ratio of the peak intensity of the Kα ray of the F element in the fluoride phosphor to the peak intensity of the Kα ray of the F element in the fluoride particles is 80% or less. Fluoride phosphor according to any one of. The fluoride particles have, on their surfaces, a rare earth phosphate containing at least one rare earth element selected from the group consisting of La, Ce, Dy and Gd, and the oxide comprises the rare earth phosphate. 6. The fluoride phosphor according to any one of claims 1 to 5, which coats the fluoride particles through the holes. 10. The fluoride phosphor according to claim 9, wherein said rare earth phosphate contains lanthanum. 10. The fluoride phosphor according to claim 9, wherein the content of the rare earth phosphate is 0.1% by mass or more and 20% by mass or less as the content of the rare earth element. A method for producing a fluoride phosphor, comprising an element M containing at least one selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, an alkali metal, Mn, and F , When the number of moles of the alkali metal is 2, the number of moles of Mn is more than 0 and less than 0.2, and the number of moles of the element M is more than 0.8 and less than 1, preparing fluoride particles having a composition in which the number of moles of F is greater than 5 and less than 7;
Derived from the metal alkoxide by contacting the prepared fluoride particles with a metal alkoxide containing at least one selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn in a liquid medium and covering at least part of the surface of the fluoride particles with an oxide in an amount of 2% by mass or more and 30% by mass or less with respect to the fluoride phosphor. A method for producing a fluoride phosphor, comprising an element M containing at least one selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, an alkali metal, Mn, and F , When the number of moles of the alkali metal is 2, the number of moles of Mn is more than 0 and less than 0.2, and the number of moles of the element M is more than 0.8 and less than 1, preparing fluoride particles having a composition in which the number of moles of F is greater than 5 and less than 7;
In a liquid medium, the prepared fluoride particles, rare earth ions containing at least one selected from the group consisting of La, Ce, Dy and Gd, and phosphate ions are brought into contact to form a rare earth phosphate. obtaining attached fluoride particles;
By contacting the fluoride particles to which the rare earth phosphate is attached and a metal alkoxide containing at least one selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn in a liquid medium, the an oxide derived from a metal alkoxide covering at least a portion of the surface of the fluoride particles to which the rare earth phosphate is attached in an amount of 2% by mass or more and 30% by mass or less relative to the fluoride phosphor; Manufacturing method including. The prepared fluoride particles contain at least one of Si and Ge as an element M in their composition, and when the number of moles of the alkali metal is 2, the total number of moles of Si, Ge, and Mn is 0.9 or more. 14. The production method according to claim 12 or 13, which is 1.1 or less. 15. The manufacturing method according to claim 14, wherein the prepared fluoride particles have a composition represented by the following formula (1).
A ¹ _c [M ¹ _1-b Mn _b F _d ] (1)
(In formula (1), A ¹ contains at least one selected from the group consisting of Li, Na, K, Rb and Cs. M ¹ contains at least one of Si and Ge, Group 4 and at least one element selected from the group consisting of the elements of Group 14. b satisfies 0<b<0.2, and c is the [M ² _1-b Mn _b F _d ] ion is the absolute value of the charge of , and d satisfies 5<d<7.) The prepared fluoride particles contain Si and Al as elements M in their composition, and when the number of moles of the alkali metal is 2, the total number of moles of Si, Al, and Mn is 0.9 or more and 1.1. or less, and the number of moles of Al is more than 0 and 0.1 or less. 17. The manufacturing method according to claim 16, wherein the prepared fluoride particles have a composition represented by the following formula (2).
A ² _f [M ² _1-e Mn _e F _g ] (2)
(In formula (2), A ² contains at least one selected from the group consisting of Li, Na, K, Rb and Cs. M ² contains at least Si and Al, a group 4 element, a It may further contain at least one element selected from the group consisting of elements of Group 13 and elements of Group 14. e satisfies 0<e<0.2, and f is [M ² _1-e Mn _e F _g ] is the absolute value of the charge of the ion, and g satisfies 5<g<7.) 14. The production method according to claim 12 or 13, further comprising performing a silane coupling treatment after covering at least part of the surface of the fluoride particles with the oxide derived from the metal alkoxide. 14. The production method according to claim 12 or 13, wherein said metal alkoxide contacted in said liquid medium contains at least one selected from the group consisting of tetramethoxysilane, tetraethoxysilane and tetraisopropoxysilane. A light-emitting device comprising a fluorescent member containing the fluoride phosphor according to any one of claims 1 to 5 and a resin, and a light-emitting element having an emission peak wavelength in a wavelength range of 380 nm or more and 485 nm or less.

Images