JP7277788B2 - Method for manufacturing wavelength conversion member and wavelength conversion member - Google Patents

Description

The present invention provides a method for manufacturing a wavelength conversion member that converts the wavelength of light emitted from a light emitting diode (hereinafter also referred to as "LED") or a laser diode (hereinafter also referred to as "LD"). and a wavelength conversion member.

Light-emitting devices using light-emitting elements such as LEDs and LDs are light sources with high conversion efficiency, consume less power, have a long life, and can be made smaller. It's being used. In such a light-emitting device, a light-emitting element as a light source and a wavelength conversion member that absorbs part of the light emitted from the light-emitting element and converts it into a different wavelength are housed in a package. Light-emitting devices using LEDs and LDs are used in a wide range of fields such as light-emitting devices for vehicles and indoor lighting, backlight sources for liquid crystal display devices, illumination, and light source devices for projectors. Among them, light-emitting devices that combine a light-emitting element that emits blue light and a phosphor that emits yellow light or the like to emit mixed-color light are widely used.

Phosphors used in such light emitting devices include rare earth aluminate phosphors represented by (Y, Gd, Tb, Lu) ₃ (Al, Ga) ₅ O ₁₂ :Ce, (Sr, Ca, Ba) Inorganic phosphors such as silicate phosphors represented by ₂ SiO ₄ :Eu and Ca-α-sialon phosphors are known. These phosphors are dispersed in a resin, and the resin containing the phosphors is cured within the package to form the wavelength conversion member. As a wavelength conversion member, for example, a wavelength conversion member made of a sintered body obtained by mixing glass powder and inorganic phosphor powder and melting and solidifying the glass powder is also disclosed (Patent Document 1).

JP 2014-234487 A

However, a wavelength conversion member made by curing a resin containing a phosphor may cause deterioration of the resin, resulting in a decrease in brightness. Further, in the wavelength conversion member disclosed in Patent Document 1, the glass component may be mixed into the inorganic phosphor during the formation of the sintered body, which may interfere with the light emission of the phosphor. In addition, glass has a relatively low softening point, and when irradiated with light from a high-power LED or LD, a sintered body obtained by melting and solidifying glass powder mixed with inorganic phosphor powder cannot withstand high temperatures. There is fear.
Accordingly, an object of the present invention is to provide a method for manufacturing a wavelength conversion member that emits light having a desired emission peak wavelength by irradiation with excitation light, and the wavelength conversion member.

Means for solving the above problems include the following aspects.

A first aspect of the present invention is to prepare a molded body obtained by molding a mixed powder containing a Ca-α-sialon phosphor and alumina particles, and heat the molded body at a temperature in the range of 1000 ° C. to 1600 ° C. A method for manufacturing a wavelength conversion member, including primary firing at a temperature to obtain a first sintered body.

A second aspect of the present invention is a wavelength conversion member containing a Ca-α-sialon phosphor and alumina.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the wavelength conversion member which emits the light which has a desired emission peak wavelength, and a wavelength conversion member can be provided.

FIG. 1 is a flow chart showing the order of steps in the method for manufacturing a wavelength conversion member according to the first embodiment of the present disclosure. FIG. 2 is a flow chart showing the process sequence of a preferred method for manufacturing a wavelength conversion member according to the first embodiment of the present disclosure. 3 is an appearance photograph of a wavelength conversion member according to Example 3. FIG. 4 is an appearance photograph of a wavelength conversion member according to Example 12. FIG. 5 is an appearance photograph of a first sintered body according to Comparative Example 5. FIG. FIG. 6 is a diagram showing the chromaticity (x value, y value) of the CIE chromaticity coordinates of each wavelength conversion member according to Examples 23-26. 7 is a diagram showing the chromaticity (x value, y value) of the CIE chromaticity coordinates of each wavelength conversion member according to Examples 27 to 30 and the first sintered body of Comparative Example 6. FIG.

Hereinafter, a method for manufacturing a wavelength conversion member and a wavelength conversion member according to the present invention will be described based on embodiments. However, the embodiments shown below are examples for embodying the technical idea of the present invention, and the present invention is not limited to the following method for manufacturing a wavelength conversion member and wavelength conversion member. The relationship between the color name and chromaticity coordinates, the relationship between the wavelength range of light and the color name of monochromatic light, etc. conform to JIS Z8110.

Method for Manufacturing Wavelength Conversion Member A method for manufacturing a wavelength conversion member according to the first embodiment of the present invention includes Ca-α-sialon phosphor, optionally yttrium aluminum garnet phosphor, and alumina particles. The method includes preparing a molded body obtained by molding a mixed powder, and primary firing the molded body at a temperature in the range of 1000° C. or higher and 1600° C. or lower to obtain a first sintered body.

The first sintered body containing the Ca-α-sialon phosphor and alumina obtained by the manufacturing method according to the first embodiment of the present invention emits light having a desired emission peak wavelength when irradiated with excitation light. It can be used as a wavelength conversion member. Since the wavelength conversion member made of the first sintered body is made of ceramics containing Ca-α-sialon phosphor and alumina, it has high thermal conductivity and high heat resistance, and can suppress deterioration. .

According to the manufacturing method according to the first embodiment of the present invention, the Ca-α-sialon phosphor maintained the crystal structure of the Ca-α-sialon phosphor without part of the crystal structure being decomposed. It is possible to obtain a wavelength conversion member composed of a sintered body containing a Ca-α-sialon phosphor that is baked together with alumina, which is an oxide, and emits light having a desired emission peak wavelength by excitation light.

In a sintered body obtained by melting and solidifying a glass powder mixed with an inorganic phosphor powder, the glass component mixes into the inorganic phosphor during the formation of the sintered body, which may interfere with the light emission of the phosphor. . When an oxynitride phosphor such as a Ca-α-sialon phosphor and alumina particles, which are one of the same oxides as the oxides contained in the glass component, are fired, the composition of the oxynitride phosphor contains Nitrogen readily reacts with oxygen in the oxide, promoting the reaction between the oxynitride and the oxide, partially decomposing the crystal structure of the oxynitride phosphor, and containing a phosphor that emits light to a practical extent. It was assumed that a sintered body could not be obtained. However, according to experiments by the present inventors, it was found that a sintered body obtained by firing a Ca-α-sialon phosphor and alumina particles actually emits light. This is because, for example, alumina is less susceptible to compositional change due to heat than metal oxides other than alumina contained in the glass component, and oxygen released from the composition of alumina reacts with the Ca-α-sialon phosphor. Therefore, even if a sintered body is formed using alumina particles, the emission of the Ca-α-sialon phosphor is unlikely to be adversely affected.

In the method for manufacturing a wavelength conversion member according to the first embodiment of the present invention, a mixed powder containing Ca-α-sialon phosphor and alumina particles is added to a yttrium aluminum garnet phosphor (hereinafter referred to as "YAG phosphor"). Also referred to as "phosphor"). When the mixed powder contains Ca-α-sialon phosphor, alumina particles, and YAG-based phosphor, the molded body obtained by molding the mixed powder is heated to a temperature in the range of 1000 ° C. or higher and 1500 ° C. or lower. It is preferable to obtain a first sintered body by performing primary sintering at. In the wavelength conversion member obtained by the manufacturing method according to the first embodiment of the present invention, the crystal structure of the Ca-α-sialon phosphor and the crystal structure of the YAG-based phosphor are not partially decomposed. While maintaining the crystal structure of the phosphor, it is sintered together with alumina, which is an oxide, to form a first sintered body. The production method according to the first embodiment of the present invention produces a Ca-α-sialon phosphor and a YAG phosphor while maintaining the crystal structure of the Ca-α-sialon phosphor and the crystal structure of the YAG phosphor. Since it can be included in one sintered body, the Ca-α-sialon phosphor and the YAG-based phosphor contained in one sintered body can be combined without using a phosphor with a different composition to obtain a desired color tone. A wavelength conversion member that emits light in a desired color tone can be obtained by adjusting the blending amount of the body. Since the wavelength conversion member made of the first sintered body is made of ceramic containing Ca-α-sialon phosphor, YAG-based phosphor, and alumina, it has high thermal conductivity, high heat resistance, and is resistant to deterioration. can be suppressed.

Ca-α-sialon phosphor Ca-α-sialon phosphor having a composition represented by the following formula (I) is preferably used as the Ca-α-sialon phosphor.
_Cav (Si,Al) ₁₂ (O,N) ₁₆ :Eu(I)
(In formula (I), v is a number that satisfies 0<v≦2.)
In this specification, a plurality of elements separated by commas (,) in the composition formula means that at least one of these elements is contained in the composition. The plurality of elements described separated by commas (,) in the composition formula includes at least one element selected from the plurality of elements separated by commas in the composition, and two or more elements from the plurality of elements may be included in combination with

As the Ca-α-sialon phosphor, it is more preferable to use a Ca-α-sialon phosphor having a composition represented by the following formula (II).
_{MkSi12- (m+n)} Alm _{+ nOnN16 -n} : Eu (II)
(In formula (II), M is at least one element selected from the group consisting of Li, Mg, Ca, Sr, Y and lanthanoid elements (excluding La and Ce); k, m, n is a number that satisfies 0<k≦2.0, 2.0≦m≦6.0, and 0≦n≦1.0.)

In the manufacturing method according to the first embodiment of the present invention, the Ca-α-sialon phosphor is used as a raw material for the first sintered body. The Ca-α-sialon phosphor as a raw material is preferably powder. The average particle size of the Ca-α-sialon phosphor is preferably in the range of 2 μm or more and 30 μm or less, more preferably in the range of 3 μm or more and 25 μm or less, still more preferably in the range of 4 μm or more and 20 μm or less. The range is preferably 5 μm or more and 15 μm or less. When the Ca-α-sialon phosphor has an average particle diameter of 2 μm or more, the Ca-α-sialon phosphor is dispersed substantially uniformly in the mixed powder, and the Ca-α-sialon phosphor is dispersed in the compact. It can be dispersed substantially uniformly. When the Ca-α-sialon phosphor has an average particle diameter of 30 μm or less, the number of voids in the wavelength conversion member is reduced, so that the light conversion efficiency can be increased. In this specification, the average particle size of the Ca-α-sialon phosphor means the particle size (median diameter). In the laser diffraction scattering particle size distribution measurement method, for example, a laser diffraction particle size distribution analyzer (MASTER SIZER 3000, manufactured by MALVERN) can be used.

The content of the Ca-α-sialon phosphor is preferably 0.1% by mass or more and 40% by mass or less, more preferably 0% by mass, based on 100% by mass of the mixed powder constituting the molded body. 0.5% by mass or more and 38% by mass or less, more preferably 0.8% by mass or more and 35% by mass or less, and even more preferably 1% by mass or more and 30% by mass or less. When the content of the Ca-α-sialon phosphor is 0.1% by mass or more and 40% by mass or less with respect to 100% by mass of the mixed powder constituting the molded body, a wavelength conversion member having high light conversion efficiency is obtained. be able to. If the content of the Ca-α-sialon phosphor in the mixed powder constituting the molded body is less than 0.1% by mass, a wavelength conversion member having desired conversion efficiency cannot be obtained. Further, when the content of the Ca-α-sialon phosphor in the mixed powder constituting the molded body exceeds 40% by mass, the content of the alumina particles becomes relatively small, and the density of the obtained wavelength conversion member becomes low. It may become smaller and the mechanical strength may decrease. In addition, when the content of the Ca-α-sialon phosphor exceeds 40% by mass, the content of the Ca-α-sialon phosphor per volume in the wavelength conversion member is too large. In order to obtain , the thickness of the wavelength conversion member must be reduced, and the desired strength of the wavelength conversion member cannot be obtained, which may make handling difficult.

YAG Phosphor A rare earth aluminate phosphor represented by (Y, Gd, Tb, Lu) ₃ Al ₅ O ₁₂ :Ce can be used as the YAG phosphor.

As the YAG phosphor, it is preferable to use a rare earth aluminate phosphor having a composition represented by the following formula (III).
(Y _1-ab Gd _a Ce _b ) ₃ Al ₅ O ₁₂ (III)
(In formula (III), a and b are numbers satisfying 0≦a≦0.500 and 0<b≦0.030.)

In the manufacturing method according to the first embodiment of the present invention, the YAG-based phosphor is used as the raw material for the first sintered body. The YAG-based phosphor as a raw material is preferably powder. The average particle diameter of the YAG phosphor is preferably in the range of 1 μm to 50 μm, more preferably in the range of 1 μm to 40 μm, still more preferably in the range of 2 μm to 30 μm, and even more preferably 2 μm. It is in the range of 20 µm or more and 20 µm or less, and particularly preferably in the range of 2 µm or more and 15 µm or less. When the average particle diameter of the YAG phosphor is 1 μm or more, the YAG phosphor can be dispersed substantially uniformly in the mixed powder, and the YAG phosphor can be dispersed substantially uniformly in the compact. When the average particle diameter of the YAG-based phosphor is 50 μm or less, the number of voids in the wavelength conversion member is reduced, so that the light conversion efficiency can be increased. In the present specification, the average particle size of the YAG-based phosphor means an average particle size (Fisher Sub-sieve sizer's number ). The FSSS method is a kind of air permeation method, and is a method of measuring the specific surface area using air flow resistance and determining the particle size.

The total content of the YAG-based phosphor and the Ca-α-sialon phosphor is preferably 0.1% by mass or more and 70% by mass with respect to 100% by mass of the mixed powder constituting the molded body. % or less, more preferably 0.5% by mass or more and 65% by mass or less, still more preferably 0.8% by mass or more and 60% by mass or less, even more preferably 1% by mass or more and 55% by mass or less, particularly preferably 2% by mass It is more than 50 mass % or less. When the total content of the Ca-α-sialon phosphor and the YAG phosphor is 0.1% by mass or more and 70% by mass or less with respect to 100% by mass of the mixed powder constituting the molded body, the light conversion efficiency can obtain a high wavelength conversion member. When the total content of the Ca-α-sialon phosphor and the YAG phosphor is less than 0.1% by mass with respect to 100% by mass of the mixed powder constituting the molded body, the wavelength having the desired conversion efficiency Unable to obtain a conversion member. Further, when the total content of the Ca-α-sialon phosphor and the YAG phosphor exceeds 70% by mass with respect to 100% by mass of the mixed powder constituting the molded body, the content of the phosphor is relatively increased. Therefore, in order to obtain a desired wavelength conversion efficiency or a desired color tone, the thickness of the first sintered body needs to be reduced. The first sintered body, which is thinned to obtain a desired color tone, does not have a desired strength as a wavelength conversion member and may be difficult to handle. Further, when the total content of the Ca-α-sialon phosphor and the YAG phosphor with respect to 100% by mass of the mixed powder constituting the molded body exceeds 70%, the amount of phosphor particles contained in the molded body is As a result, the amount of alumina becomes relatively small, which may make it difficult to increase the relative density of the obtained wavelength conversion member.

The mixing ratio of the Ca-α-sialon phosphor and the YAG-based phosphor in the mixed powder that constitutes the molded body is the Ca-α-sialon phosphor with respect to 100% by mass of the mixed powder that constitutes the molded body The content of is in the range of 0.1% by mass to 40% by mass, and the total content of the Ca-α-sialon phosphor and the YAG phosphor is in the range of 0.1% by mass to 70% by mass It is sufficient that the desired wavelength conversion efficiency is obtained and the desired color tone is obtained. The total content of the Ca-α-sialon phosphor particles and the YAG-based phosphor particles is 0.1% by mass or more and 70% by mass or less with respect to 100% by mass of the mixed powder constituting the molded body, and Ca-α- If the content of the sialon phosphor is 0.1% by mass or more and 40% by mass or less, for example, the mass ratio between the Ca-α-sialon phosphor particles and the YAG phosphor particles (Ca-α-sialon phosphor particles: YAG The mass ratio of charged phosphor particles) is preferably in the range of 1:99 to 99:1, more preferably in the range of 2:98 to 98:2, still more preferably 3:97 to 95: 5, and more preferably 4:96 to 90:10.

The total content of the YAG-based phosphor is 0.1% by mass or more and 70% by mass with respect to 100% by mass of the mixed powder constituting the molded body. % or less, and the content of the Ca-α-sialon phosphor should be in the range of 0.1 mass % or more and 40 mass % or less. The content of the YAG-based phosphor is preferably 0.1% by mass or more and 69.9% by mass or less, more preferably 0.1% by mass or more and 69.9% by mass or less, more preferably 0.1% by mass or more, and more preferably 0.9% by mass or less. 5% by mass or more and 60% by mass or less, more preferably 0.8% by mass or more and 50% by mass or less, even more preferably 1% by mass or more and 40% by mass or less, and particularly preferably 1% by mass or more and 30% by mass or less. A wavelength conversion member capable of obtaining a desired color tone when the content of the YAG-based phosphor is in the range of 0.1% by mass or more and 69.9% by mass or less with respect to 100% by mass of the mixed powder constituting the molded body. can be obtained.

Alumina Particles In the manufacturing method according to the first embodiment of the present invention, alumina particles are used as a raw material for the first sintered body. The alumina particles used as a raw material preferably have an alumina purity of 99.0% by mass or more, more preferably 99.5% by mass or more. When the powder constituting the molded body contains alumina particles having an alumina purity of 99.0% by mass or more, the obtained first sintered body or second sintered body has high transparency, and light conversion Efficiency can be increased, and a wavelength conversion member having good thermal conductivity can be obtained. When commercially available alumina particles are used, the alumina purity value described in the catalog can be referred to. If the alumina purity is unknown, after measuring the mass of the alumina particles, each alumina particle is fired at 800 ° C. for 1 hour in an air atmosphere so that the organic matter adhering to the alumina particles and the alumina particles absorb moisture. The purity of alumina can be measured by removing the moisture contained in the powder, measuring the mass of the alumina particles after firing, and dividing the mass of the alumina particles after firing by the mass of the alumina particles before firing. Alumina purity can be calculated, for example, by the following formula.
Alumina purity (mass%) = (mass of alumina particles after firing / mass of alumina particles before firing) x 100

The average particle size of the alumina particles is preferably in the range of 0.1 μm or more and 1.3 μm or less, more preferably 0.2 μm or more and 1.0 μm or less, still more preferably 0.3 μm or more and 0.8 μm. The range is as follows, more preferably 0.3 μm or more and 0.6 μm or less. When the average particle diameter of the alumina particles is within the above range, the powder of the Ca-α-sialon phosphor and the alumina particles can be uniformly mixed, and the wavelength conversion member made of the sintered body with few voids and high density can be obtained. can be manufactured. In the present specification, the average particle size of alumina particles refers to the average particle size (Fisher sub-sieve sizer's number) measured by a Fisher sub-sieve sizer (hereinafter also referred to as "FSSS") method. .

The content of the alumina particles is the remainder excluding the phosphor with respect to 100% by mass of the mixed powder constituting the compact. When the mixed powder constituting the molded body is composed of the Ca-α-sialon phosphor and the alumina particles, the content of the alumina particles is the remainder of the mixed powder excluding the Ca-α-sialon phosphor, It is preferably 60% by mass or more and 99.9% by mass or less.
When the mixed powder constituting the molded body is composed of the Ca-α-sialon phosphor, the YAG-based phosphor, and the alumina particles, the content of the alumina particles is the Ca-α-sialon from the mixed powder. It is the remainder excluding the total amount of the phosphor and the YAG-based phosphor, and is preferably 30% by mass or more and 99.9% by mass or less.

The type of alumina constituting the alumina particles is not particularly limited, and any of γ-alumina, δ-alumina, θ-alumina and α-alumina can be used. It is preferable to use α-alumina because alumina is easily available, and the Ca-α-sialon phosphor powder and alumina particles can be easily mixed to form a compact.

A method for manufacturing a wavelength conversion member according to the first embodiment of the present invention comprises: a first sintered body containing Ca-α-sialon phosphor and alumina particles; : 2000, No. 2112 (HIP: Hot Isostatic Pressing, hereinafter also referred to as “HIP”) treatment is performed at a temperature in the range of 1000° C. or higher and 1600° C. or lower to obtain a second sintered body. The second sintered body obtained by the method for manufacturing a wavelength conversion member is secondary fired at a temperature in the range of 1000 ° C. or higher and 1600 ° C. or lower by HIP treatment of the first sintered body. The density of the sintered body can be further increased, and the sintered body can be used as a wavelength conversion member that emits light having a desired emission peak wavelength and less color unevenness when irradiated with excitation light.

Further, the method for manufacturing a wavelength conversion member according to the first embodiment of the present invention includes a first sintered body containing a Ca-α-sialon phosphor, optionally a YAG phosphor, and alumina particles is further subjected to secondary firing at a temperature in the range of 1000° C. or higher and 1500° C. or lower by HIP treatment to obtain a second sintered body. The second sintered body obtained by the method for manufacturing a wavelength conversion member is obtained by secondary firing of the first sintered body at a temperature in the range of 1000 ° C. or higher and 1500 ° C. or lower by HIP treatment. The density of the sintered body can be further increased, and it can be used as a wavelength conversion member that emits light having a desired emission peak wavelength and less color unevenness when irradiated with excitation light.

FIG. 1 is a flow chart showing an example of the order of steps in a method for manufacturing a wavelength conversion member according to the first embodiment. The steps of the method for manufacturing the wavelength conversion member will be described with reference to FIG. The method for manufacturing a wavelength conversion member includes a compact preparation step S102 and a primary firing step S103. The wavelength conversion member manufacturing method may include a powder mixing step S101 before the compact preparation step S102, and may include a processing step S104 for processing the wavelength conversion member after the primary firing step S103. good.

Powder Mixing Step In the powder mixing step, Ca-α-sialon phosphor powder and alumina particles are mixed as powders constituting the compact. In the powder mixing step, it is preferable to mix a Ca-α-sialon phosphor, optionally a YAG-based phosphor, and alumina particles as powders constituting the compact. Powder mixing can be performed using a mortar and pestle. Powders may be mixed using a mixing medium such as a ball mill. In addition, a molding aid may be used to facilitate mixing of the powder and molding of the mixed powder. Molding aids include water or ethanol. It is preferable that the molding aid is easily volatilized in the subsequent baking step. A molding aid may not be used. When a molding aid is added, it is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 5 parts by mass or less per 100 parts by mass of the powder.

Molded body preparation step In the molded body preparation step, a mixed powder containing Ca-α-sialon phosphor, optionally YAG phosphor, and alumina particles is molded into a desired shape to obtain a molded body. . As a method for molding the mixed powder, a known method such as a press molding method can be adopted. Also referred to as "processing".) and the like. As for the molding method, two types of methods may be adopted in order to adjust the shape of the molded body, and CIP treatment may be performed after mold press molding. In the CIP treatment, it is preferable to press the compact using water as a medium.

The pressure during mold press molding is preferably 3 MPa to 50 MPa, more preferably 4 MPa to 20 MPa. If the pressure at the time of mold press molding is within the above range, the molded body can be arranged into a desired shape.

The pressure in CIP treatment is preferably 50 MPa to 250 MPa, more preferably 100 MPa to 200 MPa. When the pressure in the CIP treatment is within the above range, the density of the molded body can be increased, and a molded body having a substantially uniform density as a whole can be obtained. It can increase body density.

Primary sintering step In the primary sintering step, a molded body obtained by molding a mixed powder containing Ca-α-sialon phosphor and alumina particles is primarily sintered at a temperature in the range of 1000 ° C. or higher and 1600 ° C. or lower, and is first sintered. It is the process of obtaining a body. In the primary firing step, when the molded body contains the Ca-α-sialon phosphor, the YAG phosphor, and the alumina particles, the primary firing is performed at a temperature in the range of 1000 ° C. or higher and 1500 ° C. or lower, and the first is a step of obtaining a sintered body. In the primary firing step, the sintering density of the Ca-α-sialon phosphor and alumina particles contained in the molded body is increased, and a wavelength conversion member that emits light having a desired emission peak wavelength by excitation light can be obtained.

A molded body obtained by molding a mixed powder containing a Ca-α-sialon phosphor and alumina particles is primarily fired at a temperature of 1000° C. or more and 1600° C. or less to obtain a first sintered body. In the secondary firing, the density of the obtained second sintered body can be further increased. The first sintered body obtained by the primary firing process may have a lower density than the second sintered body obtained by the secondary firing process described later, but the first sintered body obtained by the primary firing process The body emits light having a desired emission peak wavelength when irradiated with excitation light, and can be used as a wavelength conversion member.

Depending on the temperature and the content of the Ca-α-sialon phosphor in the first sintered body, the closed pores contained in the first sintered body are crushed by the secondary firing by the HIP treatment, and the second Since the Ca-α-sialon phosphor contained in the first sintered body is partially decomposed and evaporated to generate open pores in the second sintered body, the first sintered body may have a higher density than the second sintered body.

The temperature of the primary firing is in the range of 1000°C or higher and 1600°C or lower. If the primary firing temperature is less than 1000° C., the relative density cannot be increased. When the primary firing temperature exceeds 1600° C., the Ca-α-sialon phosphor reacts with the alumina particles in the molded body, the crystal structure of the Ca-α-sialon phosphor is decomposed, and the obtained first The sintered body of does not emit light even when irradiated with excitation light. The primary firing temperature is preferably in the range of 1100° C. or higher and lower than 1600° C., more preferably 1100° C. or higher and 1580° C. or lower, still more preferably 1200° C. or higher and 1570° C. or lower. It is more preferably in the range of 1300°C or higher and 1560°C or lower, still more preferably in the range of 1400°C or higher and 1550°C or lower, still more preferably in the range of 1400°C or higher and 1540°C or lower, and still more preferably 1450°C. It is in the range of 1,540° C. or higher, and more preferably in the range of 1,470° C. or higher and 1,540° C. or lower. The temperature of the primary firing may be in the range of 1400°C or higher and 1500°C or lower.

When the compact is formed by molding a mixed powder containing a YAG-based phosphor together with a Ca-α-sialon phosphor and alumina particles, the primary firing temperature should be in the range of 1000° C. or higher and 1500° C. or lower. preferable. In the case where the molded body is formed by molding a mixed powder containing a YAG phosphor together with a Ca-α-sialon phosphor, if the primary firing temperature is in the range of 1000 ° C. or higher and 1500 ° C. or lower, Ca-α- Even with a molded body obtained by molding a mixed powder containing a YAG-based phosphor together with a sialon phosphor, the crystal structure of the Ca-α-sialon phosphor contained in the molded body is not decomposed, and excitation light can be emitted. A first sintered body that emits light having a desired emission peak wavelength can be obtained by irradiation. The temperature of the primary firing of the molded body obtained by molding the mixed powder containing the Ca-α-sialon phosphor, the YAG phosphor and the alumina particles is preferably in the range of 1100° C. or higher and 1500° C. or lower, more preferably 1100° C. °C or higher and 1450 °C or lower, more preferably 1200 °C or higher and 1450 °C or lower.

The primary sintering includes the atmosphere sintering method in which sintering is performed in a non-oxidizing atmosphere without applying pressure or load, the atmosphere pressure sintering method in which sintering is performed under pressure in a non-oxidizing atmosphere, and hot pressing. A sintering method and a discharge plasma sintering method (SPS: Spark Plasma Sintering) can be mentioned.

The primary firing is preferably performed in an atmosphere containing nitrogen gas. The atmosphere containing nitrogen gas is an atmosphere containing at least 99% by volume of nitrogen gas. The nitrogen gas content in the atmosphere containing nitrogen gas is preferably 99% by volume or more, more preferably 99.5% by volume or more. The atmosphere containing nitrogen gas may contain a small amount of gas such as oxygen in addition to nitrogen gas, but the content of oxygen in the atmosphere containing nitrogen gas should be 1% by volume or less. is preferably 0.5% by volume or less, more preferably 0.1% by volume or less, even more preferably 0.01% by volume or less, and particularly preferably 0.001% by volume or less. When the atmosphere of the primary firing is an atmosphere containing nitrogen gas, deterioration of the crystal structure of the Ca-α-sialon phosphor in the primary firing is suppressed, and the first firing atmosphere containing the Ca-α-sialon phosphor maintaining the crystal structure is suppressed. A sintered body can be obtained.

The atmospheric pressure for primary firing is preferably in the range of 0.2 MPa or more and 200 MPa or less. Ambient pressure refers to gauge pressure. The primary firing is preferably performed under an atmospheric pressure in the range of 0.2 MPa or more and 200 MPa or less. The Ca-α-sialon phosphor, which is an oxynitride, decomposes more easily as the temperature rises. A first sintered body having a more suppressed and high emission intensity is obtained. The gauge pressure of the atmosphere is more preferably 0.2 MPa or more and 1.0 MPa or less, more preferably 0.8 MPa or more and 1.0 MPa or less.

The primary firing time may be appropriately selected according to the atmospheric pressure. The heat treatment time is, for example, 0.5 hours or more and 20 hours or less, preferably 1 hour or more and 10 hours or less.

FIG. 2 is a flow chart showing an example of the order of steps in a preferred method for manufacturing a wavelength conversion member according to the first embodiment. A preferred method for manufacturing a wavelength conversion member includes a molded body preparation step S202, a primary firing step S203, and a secondary firing step S204. A preferred method for manufacturing a wavelength conversion member may include a powder mixing step S201 before the molded body preparation step S202, and a processing step S205 for processing the wavelength conversion member after the secondary firing step S204. You can

Secondary Firing Step In the secondary firing step, the first sintered body obtained by primary firing the molded body obtained by molding the mixed powder containing the Ca-α-sialon phosphor and the alumina particles is subjected to HIP treatment to 1000 C. to 1600.degree. C. to obtain a second sintered body. In the secondary firing step, the HIP treatment can further reduce the voids contained in the first sintered body and increase the density of the second sintered body. The high-density second sintered body obtained by HIP treatment has higher transparency. The second sintered body obtained by the secondary firing step can further increase the density of the sintered body, emits light having a desired emission peak wavelength when irradiated with excitation light, and can be used as a wavelength conversion member. can.

The secondary firing temperature is in the range of 1000° C. or higher and 1600° C. or lower. If the secondary firing temperature is less than 1000° C., the second sintered body having a higher relative density than the first sintered body cannot be obtained even if the secondary firing is performed. When the secondary firing temperature exceeds 1600° C., the Ca-α-sialon phosphor reacts with the alumina particles in the first sintered body, and part of the crystal structure of the Ca-α-sialon phosphor decomposes. As a result, the emission intensity of the obtained second sintered body is lowered. The secondary firing temperature is preferably in the range of 1100° C. or higher and 1580° C. or lower, more preferably in the range of 1200° C. or higher and 1570° C. or lower, still more preferably in the range of 1300° C. or higher and 1560° C. or lower. It is preferably in the range of 1400°C or higher and 1550°C or lower.

When the first sintered body is a molded body obtained by molding mixed powder containing YAG-based phosphor together with Ca-α-sialon phosphor and alumina particles, the secondary firing temperature is 1000 ° C. to 1500 ° C. The following ranges are preferred. When the first sintered body contains the YAG phosphor together with the Ca-α-sialon phosphor, Ca-α-sialon fluorescence can be obtained if the secondary firing temperature is in the range of 1000 ° C. or higher and 1500 ° C. or lower. YAG-based phosphor is included in the molded body together with the body, and even if a trace amount of the YAG-based phosphor is contained in the YAG-based phosphor, for example, even if a fluorine-containing compound that functions as a flux in the manufacturing process remains, a trace amount The density of the sintered body can be increased without the crystal structure of the Ca-α-sialon phosphor being decomposed by the residual fluorine-containing compound. The secondary firing temperature of the first sintered body containing the Ca-α-sialon phosphor, the YAG phosphor, and the alumina particles is preferably in the range of 1100°C or higher and 1500°C or lower, more preferably 1100°C. It is in the range of 1,450° C. or higher, and more preferably in the range of 1,200° C. or higher and 1,450° C. or lower.

Secondary firing is preferably performed in an inert gas atmosphere. An inert gas atmosphere means an atmosphere containing argon, helium, nitrogen, or the like as a main component. Here, the atmosphere containing argon, helium, nitrogen, etc. as a main component means that the atmosphere contains 50% by volume or more of at least one gas selected from the group consisting of argon, helium and nitrogen. The content of oxygen in the inert gas atmosphere is preferably 1% by volume or less, more preferably 0.5% by volume or less, still more preferably 0.1% by volume or less, and even more preferably 0.01% by volume. % or less, particularly preferably 0.001 volume % or less. The inert gas atmosphere may be the same atmosphere as the atmosphere containing nitrogen gas in the primary firing, and the content of nitrogen gas contained in the atmosphere containing nitrogen gas is preferably 99% by volume or more, more preferably It is 99.5% by volume or more. When the atmosphere of the secondary firing is an inert gas atmosphere, the deterioration of the crystal structure of the Ca-α-sialon phosphor in the secondary firing is suppressed, and the second containing the Ca-α-sialon phosphor maintaining the crystal structure is obtained. sintered body can be obtained.

The pressure in the HIP treatment for secondary firing is preferably 50 MPa or more and 300 MPa or less, more preferably 80 MPa or more and 200 MPa or less. When the pressure in the HIP treatment is within the above range, the entire sintered body can be uniformly made to have a higher density without deteriorating the crystal structure of the Ca-α-sialon phosphor.

The HIP treatment time for secondary firing is, for example, 0.5 hours or more and 20 hours or less, preferably 1 hour or more and 10 hours or less.

Processing Step The method for manufacturing the wavelength conversion member may include a processing step of processing the obtained wavelength conversion member made of the first sintered body or the second sintered body. The processing step includes a step of cutting the obtained wavelength conversion member into a desired size, and the like. A known method can be used for cutting the wavelength conversion member, and examples thereof include blade dicing, laser dicing, and wire sawing. Among these, a wire saw is preferable because the cut surface can be flattened with high accuracy. A desired thickness and size of the wavelength conversion member can be obtained by the processing step. The thickness of the wavelength conversion member is not particularly limited, but in consideration of mechanical strength and wavelength conversion efficiency, it is preferably in the range of 1 μm or more and 1 mm or less, more preferably 10 μm or more and 800 μm or less, still more preferably 50 μm or more and 500 μm or less. More preferably, it is in the range of 100 μm or more and 400 μm or less.

Relative Density of First Sintered Body In the wavelength conversion member manufacturing method of the first embodiment, the first sintered body obtained in the primary firing step preferably has a relative density of 80% or more, more preferably 85% or more, more preferably 90% or more, even more preferably 91% or more, and particularly preferably 92% or more. The relative density of the first sintered body may be 100%, and the relative density of the first sintered body may be 99% or less, or 98% or less. When the relative density of the first sintered body is 80% or more, it can be used as a wavelength conversion member having a desired emission peak wavelength upon irradiation with excitation light. In addition, when secondary firing is performed after primary firing, the relative density of the first sintered body is 80% or more, so that the density of the second sintered body is further increased in the secondary firing after the primary firing. Since the number of voids in the wavelength conversion member is reduced and scattering of light in the voids is suppressed, a wavelength conversion member with high light conversion efficiency can be manufactured. When the wavelength conversion member is made of the first sintered body, the relative density of the wavelength conversion member is the same as the relative density of the first sintered body.

As used herein, the relative density of the first sintered body refers to a value calculated from the apparent density of the first sintered body relative to the true density of the first sintered body. Relative density is calculated by the following formula (1).
Relative density (%) = (apparent density of first sintered body / true density of first sintered body) x 100 (1)
When the first sintered body is composed of the Ca-α-sialon phosphor and the alumina particles, the true density of the first sintered body is the mixed powder 100 for the compact constituting the first sintered body. A value obtained by multiplying the mass ratio of the Ca-α-sialon phosphor with respect to mass% by the true density of the Ca-α-sialon phosphor, and the mass ratio of alumina particles with respect to 100% by mass of the mixed powder for the molded body is the sum of the value obtained by multiplying by the true density of the alumina particles. The true density of the first sintered body is calculated from the following formula (2-1).
True density of the first sintered body = (mass ratio of Ca-α-sialon phosphor to 100% by mass of mixed powder for compact × true density of Ca-α-sialon phosphor) + (for compact Mass ratio of alumina particles to 100% by mass of mixed powder × true density of alumina particles) (2-1)
When the first sintered body is composed of the Ca-α-sialon phosphor, the YAG-based phosphor, and the alumina particles, the true density of the first sintered body is the molded body that constitutes the first sintered body. A value obtained by multiplying the true density of the Ca-α-sialon phosphor by the mass ratio of the Ca-α-sialon phosphor with respect to 100% by mass of the mixed powder for the molded body, and the mixed powder for the molded body 100% by mass A value obtained by multiplying the mass ratio of the YAG-based phosphor by the true density of the YAG-based phosphor, and the mass ratio of the alumina particles to 100% by mass of the mixed powder for the molded body. Multiply the true density of the alumina particles. It is the sum with the value obtained by The true density of the first sintered body is calculated from the following formula (2-2).
True density of the first sintered body = (mass ratio of Ca-α-sialon phosphor to 100% by mass of mixed powder for compact × true density of Ca-α-sialon phosphor) + (for compact Mass ratio of YAG phosphor with respect to 100% by mass of mixed powder x true density of YAG phosphor) + (mass ratio of alumina particles with respect to 100% by mass of mixed powder for molded body x true density of alumina particles) (2 -2)
The apparent density of the first sintered body is a value obtained by dividing the mass of the first sintered body by the volume of the first sintered body determined by the Archimedes method. The apparent density of the first sintered body is calculated by the following formula (3).
Apparent density of first sintered body = Mass of first sintered body / Volume of first sintered body obtained by Archimedes method (3)

Relative Density of Second Sintered Body The second sintered body obtained after secondary firing has a relative density of preferably 90% or more, more preferably 91% or more, still more preferably 92% or more, and even more preferably is at least 93%, particularly preferably at least 95%. When the relative density of the wavelength conversion member made of the second sintered body is 90% or more, the number of voids in the wavelength conversion member is reduced, and the light conversion efficiency can be increased. Further, since the relative density of the second sintered body is 90% or more, for example, in the processing step, the wavelength conversion member made of the processed second sintered body can be produced without chipping even if the processing is performed. Obtainable. The relative density of the second sintered body may be 100%, and the relative density of the second sintered body may be 99.9% or less, or 99.8% or less.

As used herein, the relative density of the second sintered body refers to a value calculated from the apparent density of the second sintered body relative to the true density of the second sintered body. When the wavelength conversion member is made of the second sintered body, the relative density of the wavelength conversion member is the same as that of the second sintered body. Relative density is calculated by the following formula (4).
Relative density (%) = (apparent density of second sintered body / true density of second sintered body) x 100 (4)
The method of calculating the true density of the second sintered body is calculated by the same method as the true density of the first sintered body. The true density of the second sintered body is the same value as the true density of the first sintered body.
The apparent density of the second sintered body is a value obtained by dividing the mass of the second sintered body by the volume of the second sintered body determined by the Archimedes method. The apparent density of the second sintered body is calculated by the following formula (5).
Apparent density of second sintered body = Mass of second sintered body / Volume of second sintered body obtained by Archimedes method (5)

The obtained first sintered body or second sintered body can emit light having a desired emission peak wavelength by irradiation with excitation light, and can be used as a wavelength conversion member. The first sintered body or the second sintered body having a relative density of 90% or more can increase the relative luminous intensity and the light conversion efficiency.

Wavelength Conversion Member The wavelength conversion member preferably contains Ca-α-sialon phosphor and alumina, and the content of Ca-α-sialon phosphor is 0.1% by mass or more and 40% by mass or less. Desired conversion efficiency can be obtained when the content of the Ca-α-sialon phosphor in the wavelength conversion member is 0.1% by mass or more. When the content of the Ca-α-sialon phosphor in the wavelength conversion member is large, the content of the powder of the Ca-α-sialon phosphor per volume in the wavelength conversion member is too large, resulting in the desired color tone and conversion. In order to obtain efficiency, it is necessary to reduce the volume of the wavelength conversion member. For example, in order to reduce the volume of the obtained wavelength conversion member, the thickness must be reduced, which makes handling difficult. Further, when the content of the Ca-α-sialon phosphor in the wavelength conversion member is large, the amount of alumina in the wavelength conversion member decreases relatively, and the Ca-α-sialon phosphor and alumina in the wavelength conversion member The adhesion of the film may be lowered to form voids, thereby lowering the light conversion efficiency. The content of the Ca-α-sialon phosphor in the wavelength conversion member is determined by elemental analysis of the elements constituting the Ca-α-sialon phosphor using ICP emission spectroscopy (Inductively Coupled Plasma Atomic Emission Spectroscopy). , the content of the Ca-α-sialon phosphor contained in the wavelength conversion member can be measured from the obtained elemental analysis results. The Ca-α-sialon phosphor contained in the wavelength conversion member is preferably a Ca-α-sialon phosphor having a composition represented by the formula (I) or (II).

When the wavelength conversion member contains the Ca-α-sialon phosphor, the alumina particles, and the YAG-based phosphor, the total content of the YAG-based phosphor and the Ca-α-sialon phosphor is 0.1. It is preferably at least 70% by mass and no more than 70% by mass. When the wavelength conversion member contains the Ca-α-sialon phosphor and the YAG-based phosphor, the content of the Ca-α-sialon phosphor is 0.1% by mass or more and 40% by mass or less, and Ca - When the total content of the α-sialon phosphor and the YAG-based phosphor satisfies the range of 0.1% by mass or more and 70% by mass or less, emission of a desired color tone can be obtained by irradiation with excitation light. The content of the Ca-α-sialon phosphor is 0.1% by mass or more and 40% by mass or less, and the total content of the Ca-α-sialon phosphor and the YAG phosphor is 0.1% by mass or more and 70% by mass. For example, the content of the YAG-based phosphor in the wavelength conversion member may be 69.9% by mass or 0.1% by mass, as long as the range satisfies the range of mass % or less. A rare earth aluminate phosphor represented by (Y, Gd, Tb, Lu) ₃ Al ₅ O ₁₂ :Ce can be used as the YAG phosphor contained in the wavelength conversion member. The YAG-based phosphor contained in the wavelength conversion member is preferably the YAG-based phosphor represented by the formula (III). The total content of the Ca-α-sialon phosphor and the YAG-based phosphor in the wavelength conversion member is determined by using ICP emission spectroscopy (Inductively Coupled Plasma Atomic Emission Spectroscopy), the Ca-α-sialon phosphor and YAG Elemental analysis of the elements constituting the system phosphor is performed, and the total content of the Ca-α-sialon phosphor and the YAG phosphor contained in the wavelength conversion member can be measured from the results of the obtained elemental analysis. .

The Ca-α-sialon phosphor or YAG phosphor in the wavelength conversion member is distinguished from the alumina in the wavelength conversion member by the grain boundaries of the Ca-α-sialon phosphor or YAG phosphor. The wavelength conversion member contains a Ca-α-sialon phosphor or a YAG-based phosphor having a crystal structure different from that of alumina. The bodies are integrated to form a ceramic wavelength conversion member. A wavelength conversion member according to a second embodiment of the present invention is a wavelength conversion member comprising a first sintered body or a second sintered body obtained by the manufacturing method according to the first embodiment of the present invention. It is preferably a wavelength conversion member. The wavelength conversion member made of the first sintered body or the wavelength conversion member made of the second sintered body obtained by the manufacturing method according to the first embodiment of the present invention has a relative density of 80% or more. preferable. When the relative density of the wavelength conversion member is 80% or more, the wavelength conversion member has high emission intensity and high light conversion efficiency. In addition, since the wavelength conversion member has a relative density of 80% or more, even when the ceramic wavelength conversion member is subjected to processing such as cutting, the wavelength conversion member emits light without cracking or chipping. When used in a device, the occurrence of color unevenness can be suppressed. The relative density of the wavelength conversion member is more preferably 85% or higher, still more preferably 90% or higher, even more preferably 91% or higher, and particularly preferably 92% or higher. The relative density of the wavelength converting member may be 100%, 99.9% or less, or 99.8% or less.

The wavelength return conversion member obtained by the manufacturing method of the first embodiment or the wavelength conversion member according to the second embodiment converts the excitation light emitted from the light emitting element by combining it with a light emitting element such as an LED or an LD. As a result, it is possible to configure a light emitting device that emits light having a desired emission peak wavelength and emits mixed color light from the light from the light emitting element and the light wavelength-converted by the wavelength conversion member. As the light emitting element, for example, a light emitting element that emits light in a wavelength range of 350 nm or more and 500 nm or less can be used. As the light emitting element, for example, a semiconductor light emitting element using a nitride semiconductor (In _X Al _Y Ga _1-XY N, 0≦X, 0≦Y, X+Y≦1) can be used. 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.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. The invention is not limited to these examples.

Examples 1 to 22 are from the wavelength conversion member composed of the first sintered body containing the Ca-α-sialon phosphor and alumina or the second sintered body containing the Ca-α-sialon phosphor and alumina A wavelength conversion member was manufactured. Comparative Examples 1 to 5 produced first sintered bodies containing Ca-α-sialon phosphors and metal oxides other than alumina.

Example 1
Powder Mixing Process 1 part by mass of Ca-α-sialon phosphor (product name: Aronbright variety YL-600, manufactured by Denka Co., Ltd.) having an average particle size of 13.0 μm measured by a laser diffraction scattering particle size distribution measurement method (molding 1% by mass of Ca-α-sialon phosphor with respect to 100% by mass of mixed powder for the body) and α-alumina particles with an average particle size of 0.5 μm measured by the FSSS method (product name: AA03, Sumitomo Chemical Kogyo Co., Ltd., alumina purity 99.5% by mass) were weighed and mixed using a mortar and pestle to prepare a mixed powder for a compact. In Table 1 or Table 2, the content (% by mass) of the Ca-α-sialon phosphor indicates the mass ratio of the Ca-α-sialon phosphor to 100% by mass of the mixed powder for the molded body. In Table 1 or Table 2, the content of alumina particles in each example is the remainder obtained by subtracting the content (% by mass) of the Ca-α-sialon phosphor from 100% by mass of the mixed powder for the compact.

Formed Body Preparing Step The mixed powder was filled in a mold to form a cylindrical shaped body having a diameter of 17.0 mm and a thickness of 10 mm under a pressure of 4.6 MPa (46.9 kgf/cm ² ). The resulting compact was placed in a packaging container, vacuum-packaged, and subjected to CIP treatment at 176 MPa using water as a pressure medium using a cold isostatic press (CIP) apparatus (manufactured by KOBELCO).

Primary Firing Process The obtained molded body is held in a firing furnace (manufactured by Fuji Dempa Kogyo Co., Ltd.) in a nitrogen gas atmosphere (nitrogen: 99% by volume or more) at a temperature of 0.9 MPa and 1500 ° C. for 6 hours, followed by primary firing. was performed to obtain a first sintered body. The obtained first sintered body 1 was used as a wavelength conversion member. The content (% by mass) of the Ca-α-sialon phosphor in the wavelength conversion member composed of the first sintered body 1 of Example 1 is the Ca-α-sialon with respect to 100% by mass of the mixed powder for the compact. It is almost equal to the mass ratio of charged phosphor.

Example 2
First sintered body 2 was prepared in the same manner as in Example 1, except that mixed powder was prepared by mixing 3 parts by mass of Ca-α-sialon phosphor and 97 parts by mass of α-alumina particles. was obtained and used as a wavelength conversion member. In Examples 2 to 22, the content of the Ca-α-sialon phosphor in the wavelength conversion member composed of the first sintered body or the second sintered body is based on 100% by mass of the mixed powder for the compact. It is almost equal to the mass ratio of the charged Ca-α-sialon phosphor.

Example 3
First sintered body 3 was prepared in the same manner as in Example 1, except that mixed powder was prepared by mixing 5 parts by mass of Ca-α-sialon phosphor and 95 parts by mass of α-alumina particles. was obtained and used as a wavelength conversion member.

Example 4
First sintered body 4 was prepared in the same manner as in Example 1, except that mixed powder was prepared by mixing 10 parts by mass of Ca-α-sialon phosphor and 90 parts by mass of α-alumina particles. was obtained and used as a wavelength conversion member.

Example 5
First sintered body 5 was prepared in the same manner as in Example 1, except that mixed powder was prepared by mixing 20 parts by mass of Ca-α-sialon phosphor and 80 parts by mass of α-alumina particles. was obtained and used as a wavelength conversion member.

Example 6
Mixed powder was prepared by mixing 5 parts by mass of Ca-α-sialon phosphor and 95 parts by mass of α-alumina particles, and the same procedure as in Example 1 was performed except that the primary firing temperature was set to 1400 ° C. , a first sintered body 6 was obtained and used as a wavelength conversion member.

Example 7
Mixed powder was prepared by mixing 5 parts by mass of Ca-α-sialon phosphor and 95 parts by mass of α-alumina particles, and the same procedure as in Example 1 was performed except that the primary firing temperature was set to 1450 ° C. , a first sintered body 7 was obtained and used as a wavelength conversion member.

Example 8
Mixed powder was prepared by mixing 5 parts by mass of Ca-α-sialon phosphor and 95 parts by mass of α-alumina particles, and the same procedure as in Example 1 was performed except that the primary firing temperature was set to 1550 ° C. , a first sintered body 8 was obtained and used as a wavelength conversion member.

Example 9
Mixed powder was prepared by mixing 5 parts by mass of Ca-α-sialon phosphor and 95 parts by mass of α-alumina particles. Thus, a first sintered body 9 was obtained and used as a wavelength conversion member.

Example 10
Secondary firing process Using the first sintered body 1 obtained in Example 1, using a hot isostatic pressing (HIP) apparatus (manufactured by KOBELCO), nitrogen gas is used as a pressure medium. Under a gas atmosphere (nitrogen: 99% by volume or more), secondary firing is performed by HIP treatment at 1500 ° C. and 195 MPa for 2 hours to obtain a second sintered body 10, which is the second sintered body. 10 was used as a wavelength conversion member.

Example 11
Secondary firing step Using the first sintered body 2 obtained in Example 2, HIP treatment was performed in the same manner as in Example 10 to obtain a second sintered body 11, and this second sintered body The body 11 was used as a wavelength conversion member.

Example 12
Secondary firing step Using the first sintered body 3 obtained in Example 3, HIP treatment was performed in the same manner as in Example 10 to obtain a second sintered body 12, and this second sintering The body 12 was used as a wavelength conversion member.

Example 13
Secondary firing step Using the first sintered body 4 obtained in Example 4, HIP treatment was performed in the same manner as in Example 10 to obtain a second sintered body 13, and this second sintering The body 13 was used as a wavelength conversion member.

Example 14
Secondary firing step Using the first sintered body 5 obtained in Example 5, HIP treatment was performed in the same manner as in Example 10 to obtain a second sintered body 14, and this second sintering The body 14 was used as a wavelength conversion member.

Example 15
Secondary firing step Using the first sintered body 6 obtained in Example 6, HIP treatment was performed in the same manner as in Example 10 to obtain a second sintered body 15, and this second sintered body The body 15 was used as a wavelength conversion member.

Example 16
Secondary sintering step Using the first sintered body 7 obtained in Example 7, HIP treatment was performed in the same manner as in Example 10 to obtain a second sintered body 16, and this second sintering The body 16 was used as a wavelength conversion member.

Example 17
Secondary firing step Using the first sintered body 8 obtained in Example 8, HIP treatment was performed in the same manner as in Example 10 to obtain a second sintered body 17, and this second sintering The body 17 was used as a wavelength conversion member.

Example 18
Secondary firing step Secondary firing was performed by HIP treatment in the same manner as in Example 10, except that the first sintered body 3 obtained in Example 3 was used and the temperature was set to 1400 ° C., and the second firing was performed. A sintered body 18 was obtained, and this second sintered body 18 was used as a wavelength conversion member.

Example 19
Secondary firing step Secondary firing was performed by HIP treatment in the same manner as in Example 10, except that the first sintered body 3 obtained in Example 3 was used and the temperature was set to 1450 ° C., and the second firing was performed. A sintered body 19 was obtained, and this second sintered body 19 was used as a wavelength conversion member.

Example 20
Secondary firing step Secondary firing was performed by HIP treatment in the same manner as in Example 10, except that the first sintered body 3 obtained in Example 3 was used and the temperature was set to 1550 ° C., and the second firing was performed. A sintered body 20 was obtained, and this second sintered body 20 was used as a wavelength conversion member.

Example 21
Secondary firing step Secondary firing was performed by HIP treatment in the same manner as in Example 10, except that the first sintered body 9 obtained in Example 9 was used and the temperature was set to 1500 ° C., and the second firing was performed. A sintered body 21 was obtained, and this second sintered body 21 was used as a wavelength conversion member.

Example 22
Secondary firing step Secondary firing was performed by HIP treatment in the same manner as in Example 10 except that the first sintered body 3 obtained in Example 3 was used and the temperature was set to 1600 ° C., and the second firing was performed. A sintered body 22 was obtained, and this second sintered body 22 was used as a wavelength conversion member.

Comparative example 1
Powder mixing process 5 parts by mass of Ca-α-sialon phosphor, titanium oxide particles (manufactured by Toho Titanium Co., Ltd., titanium oxide purity 99.5% by mass, average size: 2.10 to 2.55 μm (catalog value) ) was mixed with 95 parts by mass to prepare a mixed powder. In Table 3, the content (% by mass) of the Ca-α-sialon phosphor indicates the mass ratio of the Ca-α-sialon phosphor charged to 100% by mass of the mixed powder for the compact. In Table 3, the content of the metal oxide particles in each comparative example is the remainder obtained by subtracting the content (% by mass) of the Ca-α-sialon phosphor from 100% by mass of the mixed powder for the compact. In Comparative Examples 1 to 5 and formula (2-1-1) described later, the metal oxide particles are α-alumina particles, titanium oxide particles, tantalum pentoxide particles, yttrium oxide particles, hafnium oxide particles, or zirconium oxide particles. Particles refer to any metal oxide particles.

Formed Body Preparing Step The mixed powder was filled in a mold to form a cylindrical shaped body having a diameter of 17.0 mm and a thickness of 10 mm under a pressure of 4.6 MPa (46.9 kgf/cm ² ). The resulting compact was placed in a packaging container, vacuum-packaged, and subjected to CIP treatment at 176 MPa using water as a pressure medium using a cold isostatic press (CIP) apparatus (manufactured by KOBELCO).

Primary Firing Step The obtained compact is held in a firing furnace (manufactured by Fuji Dempa Kogyo Co., Ltd.) in a nitrogen gas atmosphere (nitrogen: 99% by volume or more) at a temperature of 1500 ° C. for 6 hours to perform primary firing. A sintered body was obtained with a relative density of 71.0%. Luminescence of the first sintered body could not be confirmed. Since luminescence could not be confirmed and the relative density was as low as 71.0%, the HIP treatment of the first sintered body was not performed. When the relative density of the first sintered body is less than 80%, the voids contained in the first sintered body are large, and the second sintered body obtained by secondary firing by HIP treatment has a relative density of less than 80%. This is because the density cannot be increased to 90% or more.

Comparative example 2
5 parts by mass of Ca-α-sialon phosphor and 95 masses of tantalum pentoxide particles (manufactured by HC Starck, tantalum pentoxide purity 99.5 mass%, average particle diameter 0.7 μm by FSSS method) A first sintered body was obtained in the same manner as in Comparative Example 1, except that a mixed powder was prepared by mixing the parts with the first sintered body, and the relative density was 64.3%. Luminescence of the first sintered body could not be confirmed. Since luminescence could not be confirmed and the relative density was as low as 64.3%, HIP treatment of the first sintered body was not performed.

Comparative example 3
5 parts by mass of Ca-α-sialon phosphor and 95 parts by mass of yttrium oxide particles (manufactured by Nippon Yttrium Co., Ltd., yttrium oxide purity 99.5 mass%, average particle diameter 1.8 μm by FSSS method) were mixed. A first sintered body was obtained in the same manner as in Comparative Example 1 except that mixed powder was prepared, and the relative density was 49.6%. Luminescence of the first sintered body could not be confirmed. Since luminescence could not be confirmed and the relative density was as low as 49.6%, the HIP treatment of the first sintered body was not performed.

Comparative example 4
A mixture of 5 parts by mass of Ca-α-sialon phosphor and 95 parts by mass of hafnium oxide particles (manufactured by Kojundo Chemical Co., Ltd., hafnium oxide purity 98% by mass, average particle size 2.0 μm by FSSS method). A first sintered body was obtained in the same manner as in Comparative Example 1 except that the powder was prepared, and the relative density was 51.2%. Luminescence of the first sintered body could not be confirmed. Since luminescence could not be confirmed and the relative density was as low as 51.2%, HIP treatment of the first sintered body was not performed.

Comparative example 5
A mixture of 5 parts by mass of Ca-α-sialon phosphor and 95 parts by mass of zirconium oxide particles (manufactured by Wako Pure Chemical Industries, Ltd., zirconium oxide purity 99% by mass, average particle size 2.0 μm by FSSS method). A first sintered body was obtained in the same manner as in Comparative Example 1 except that mixed powder was prepared, and the relative density was 67.0%. Luminescence of the first sintered body could not be confirmed. Since luminescence could not be confirmed and the relative density was as low as 67.0%, HIP treatment of the first sintered body was not performed.

Measurement of Average Particle Size by Laser Diffraction Scattering Particle Size Distribution Measuring Method The particle diameter (median diameter) at which the volume cumulative frequency from the side reaches 50% was taken as the average particle diameter, and measured using a laser diffraction particle size distribution analyzer (MASTER SIZER 3000, manufactured by MALVERN).

Measurement of Average Particle Size by FSSS Method The α-alumina particles used in Examples, and the tantalum pentoxide particles, yttrium oxide particles, hafnium oxide particles and zirconium oxide particles used in Comparative Examples were measured by the FSSS method to determine the average particle size. (Fisher sub-sieve sizer's number) was measured.

Measurement of Purity of α-Alumina After measuring the mass of the α-alumina particles used in the examples, the α-alumina particles were calcined at 800° C. for 1 hour in an air atmosphere to remove the organic matter adhering to the α-alumina particles. After removing the moisture content and the moisture absorbed by the α-alumina particles, the mass of the α-alumina particles after firing is measured, and as shown in the following formula, the mass of the α-alumina particles after firing is the α- The α-alumina purity was determined by dividing by the mass of the alumina particles.
α-alumina purity (mass%) = (mass of α-alumina particles after firing/mass of α-alumina particles before firing) x 100

Measurement of Relative Density of First Sintered Body In Examples 1 to 9 and Comparative Examples 1 to 5, the relative density of each first sintered body was measured. Table 1 shows the apparent density and relative density of the first sintered bodies of Examples 1 to 9. For Comparative Examples 1 to 5, relative densities were calculated based on the following formulas (1) to (3) in the same manner as for the first sintered bodies of Examples 1 to 9. Table 3 shows the relative densities of the first sintered bodies of Comparative Examples 1 to 5.
Relative density was calculated by the following formula (1).
Relative density (%) = (apparent density of first sintered body / true density of first sintered body) x 100 (1)

The true density of the first sintered body was calculated from the following formula (2-1-1). The α-alumina particles used in Examples 1 to 9 had a true density of 3.98 g/cm ³ , and the titanium oxide particles used in Comparative Example 1 had a true density of 4.26 g/cm ³ and used in Comparative Example 2. The tantalum pentoxide particles have a true density of 8.7 g/cm ³ , the yttrium oxide particles used in Comparative Example 3 have a true density of 5.01 g/cm ³ , and the hafnium oxide particles used in Comparative Example 4 have a true density of 9.0 g/cm 3 . 68 g/cm ³ , and the true density of the zirconium oxide particles used in Comparative Example 5 was calculated as 5.6 g/cm ³ . The true density of the Ca-α-sialon phosphor was calculated as 3.22 g/cm ³ .
True density of the first sintered body = (mass ratio of Ca-α-sialon phosphor to 100% by mass of mixed powder for compact x true density of Ca-α-sialon phosphor) + (mixing for molding Mass ratio of metal oxide particles to 100% by mass of powder x true density of metal oxide particles) (2-1-1)

The apparent densities of the first sintered bodies 1 to 9 of Examples 1 to 9 and the first sintered bodies of Comparative Examples 1 to 5 were calculated by the following formula (3). Table 1 shows the mass (g) and the volume (cm ³ ) obtained by the Archimedes method of each of the first sintered bodies of Examples 1 to 9.
Apparent density of first sintered body = Mass of first sintered body / Volume of first sintered body obtained by Archimedes method (3)

Measurement of Relative Density of Second Sintered Body The relative density of the second sintered bodies 10 to 22 of Examples 10 to 22 was measured based on the following formulas (4) and (5). Table 1 shows the results. Relative density was calculated by the following formula (4).
Relative density (%) = (apparent density of second sintered body / true density of second sintered body) x 100 (4)

The method of calculating the true density of the second sintered body is based on the mass ratio of α-alumina (specifically, the α-alumina particles used in the powder mixing step) to 100% by mass of the mixed powder for the compact. - A value obtained by multiplying the true density of alumina, and the mass ratio of the Ca-α-sialon phosphor particles to 100% by mass of the mixed powder for the molded body, multiplied by the true density of the Ca-α-sialon phosphor particles It is the sum with the value obtained by For the true density of the Ca-α-sialon phosphor and the true density of α-alumina, the same values as those used in the method for calculating the true density of the first sintered body were used.

The apparent density of the second sintered body was calculated by the following formula (5).
Apparent density of second sintered body = Mass of second sintered body / Volume of second sintered body obtained by Archimedes method (5)

Measurement of Relative Emission Intensity Wavelength conversion members made of the first sintered bodies of Examples 1 to 9, wavelength conversion members made of the second sintered bodies of Examples 10 to 22, and first sintered bodies of Comparative Examples 1 to 5 The sintered body of was cut into a thickness of 300 μm using a wire saw to form a sample. Using an LED chip made of a nitride semiconductor having an emission peak wavelength of 455 nm as a light source, the sample of the wavelength conversion member was irradiated with light from this light source, and Examples 1 to 9 and Example 10 were obtained by receiving the light from the light source. The luminescence intensity of the luminescence peak wavelength in the wavelength range of 430 nm or more and 800 nm or less obtained from each sample of Examples 1 to 22 and Comparative Examples 1 to 5 was measured using a spectrofluorophotometer. The emission peak in the wavelength range of 430 nm or more and 800 nm or less obtained from each sample, with the emission intensity of the emission peak wavelength in the wavelength range of 430 nm or more and 800 nm or less obtained from the sample of the wavelength conversion member of Example 1 being 100%. The emission intensity of each wavelength was expressed as relative emission intensity (%). Table 1 shows the results of the wavelength conversion members of Examples 1 to 9. Table 2 shows the results of the wavelength conversion members of Examples 10 to 22. The samples made of the first sintered bodies of Comparative Examples 1 to 5 did not emit light even when irradiated with light from the light source. Table 3 shows the results of the first sintered bodies of Comparative Examples 1 to 5.

Photograph of Appearance A photograph of the appearance of the wavelength conversion member of Example 3 was obtained. FIG. 3 is an appearance photograph of a sample obtained by cutting the wavelength conversion member of Example 3 with a wire saw.
A photograph of the appearance of the wavelength conversion member of Example 12 was obtained. Example 12 consists of a second sintered body obtained by secondary firing of the first sintered body of Example 3. FIG. 4 is an appearance photograph of a sample obtained by cutting the wavelength conversion member of Example 12 with a wire saw.
A photograph of the appearance of the wavelength conversion member of Comparative Example 5 was obtained. FIG. 5 is an appearance photograph of a sample obtained by cutting the first sintered body of Comparative Example 5 with a wire saw.

The first sintered bodies 1 to 9 of Examples 1 to 9 and the second sintered bodies 10 to 22 of Examples 10 to 22 were irradiated with excitation light having an emission peak wavelength of 455 nm from a light source, and the emission peak wavelength was 430 nm or more. It emitted light having an emission peak wavelength in a wavelength range of 800 nm or less, and could be used as a wavelength conversion member.

As shown in Table 1, in Examples 1 to 5, the content of the Ca-α-sialon phosphor was changed from 1% by mass to 20% by mass, and the primary firing temperature was 1500 ° C. for the first sintering. The bodies 1 to 5 are obtained and used as a wavelength conversion member. As shown in Table 1, the first sintered bodies 2 to 5 of Examples 2 to 5 have a high relative density of 92% or more and a Ca-α-sialon phosphor content of 1% by mass. The relative emission intensity was higher than that of the wavelength conversion member of Example 1.

As shown in Table 1, the wavelength conversion members according to Examples 6 to 9 had a Ca-α-sialon phosphor content of 5% by mass, and the primary firing temperature was set at 1400°C or higher and 1600°C or lower. The first sintered bodies 6 to 9 were obtained by changing the materials and used as wavelength conversion members. As shown in Table 1, in the wavelength conversion member of Example 6, the primary firing temperature was 1400°C, the relative density of the first sintered body 6 was 84.5%, and the first sintered body It is speculated that there are voids in 6. From this, the wavelength conversion member of Example 6 had a relative emission intensity of 36.9%. As shown in Table 1, the wavelength conversion member of Example 7 had a primary firing temperature of 1450°C and a relative density of the first sintered body 7 of 87.2%. It was presumed that voids were also present in the body 7 . The wavelength conversion member of Example 7 had a relative density of 87.2%, and it is presumed that voids were present, so the relative emission intensity was 49.6%. As shown in Table 1, in the wavelength conversion member of Example 8, the primary firing temperature was 1550°C, the relative density of the first sintered body 8 was as high as 95.0%, and voids were suppressed and dense. The relative luminescence intensity was as high as 166.4% due to the fact that the Since the wavelength conversion member of Example 9 had a high primary firing temperature of 1600° C., the first sintered body 9 had a high relative density of 92.9%. When the primary firing temperature is high, the Ca-α-sialon phosphor, which is an oxynitride, reacts with the alumina particles, which is an oxide, and the crystal structure of the Ca-α-sialon phosphor is partially decomposed. was speculated.

As shown in Table 2, the wavelength conversion members according to Examples 10 to 14 are second sintered bodies 10 obtained by secondary firing of the first sintered bodies 1 to 5 at 1500° C. by HIP treatment. and 14, which is further densified by secondary firing by HIP treatment, and in particular, the wavelength conversion members according to Examples 11 to 14 have a relative emission intensity higher than that of the wavelength conversion member of Example 1 by 180% or more. rice field.

As shown in Table 2, except for Example 14, in Examples 10 to 22, the second sintered bodies 10 to 13 and 15 to 22 were higher than the first sintered bodies 1 to 4 and 6 to 9. had a high relative density. In Example 14, the second sintered body 14 has a slightly lower relative density than the first sintered body 5 because the Ca-α-sialon fluorescence contained in the first sintered body 5 Since the content of the body is higher than in other examples, the closed pores contained in the first sintered body 5 are crushed and densified by the HIP treatment of the secondary firing, and the Ca-α- It is considered that the sialon phosphor partially decomposes and evaporates to form open pores in the second sintered body 14 . That is, in the second sintered body 14 of Example 14, the amount of open pores generated by HIP treatment is greater than the amount of closed pores crushed by HIP treatment. It is considered that the relative density of the second sintered body 14 is slightly lower than that of the first sintered body 5 because the density is slightly higher.

As shown in Table 2, the wavelength conversion member according to Example 15 or 16 has a primary firing temperature of 1400° C. or 1450° C., and the obtained first sintered body 6 or 7 has a relative density of 90% or less. , and the relative density of the obtained second sintered body 15 or 16 was 89.0% or 91.7% even when the secondary firing by HIP treatment was performed at 1500°C. From this, the wavelength conversion member according to Example 15 or 16 has a low temperature for obtaining the first sintered body 6 or 7, so the second sintered body obtained even if secondary firing by HIP treatment is performed. It was speculated that there were numerous voids in the body.

As shown in Table 2, the wavelength conversion member according to Example 17 has a primary firing temperature as high as 1550°C, and the second sintered body 17 obtained by secondary firing at 1500°C by HIP treatment is the first The relative density was higher than that of the sintered body 8 of No. Since the wavelength conversion member has a high primary firing temperature of 1550° C., even if the secondary firing temperature is 1500° C., the Ca-α-sialon phosphor, which is an oxynitride, becomes an oxide in the primary firing stage. It is presumed that the crystal structure of the Ca-α-sialon phosphor is decomposed only partially by the secondary firing. Therefore, even if the second sintered body is densified by the secondary firing by the HIP treatment and the transparency becomes high, the wavelength conversion member has a Ca-α- It is considered that the luminescence intensity may become lower than that of the first sintered body in some cases due to decomposition of a small portion of the crystal structure of the sialon phosphor.

As shown in Table 2, in the wavelength conversion members according to Examples 18 to 20, the secondary firing temperature was changed in the range of 1400°C or higher and 1550°C or lower, and the secondary firing temperature was 1400°C or Even if the temperature of the secondary firing is 1450 ° C., which is lower than the temperature of the primary firing, and even if the temperature of the secondary firing is 1,550 ° C., which is higher than the temperature of the primary firing, a high relative density of 98.5% or more can be obtained. It was possible to obtain the second sintered bodies 18 to 20 having The wavelength conversion member made of the second sintered body 18 or 19 has a relative emission intensity higher than 200%.

The wavelength conversion member according to Example 21 emitted light when irradiated with excitation light. The wavelength conversion member according to Example 21 had a primary firing temperature of 1600° C. and a relative emission intensity of the first sintered body 9 of 59.0%. If the primary firing temperature is high, the Ca-α-sialon phosphor, which is an oxynitride, reacts with the alumina particles, which is an oxide, and the crystal structure of the Ca-α-sialon phosphor may be partially decomposed. It was speculated that there was. Even if the wavelength conversion member was subjected to secondary firing by HIP treatment after the primary firing, the relative luminous intensity was lowered when part of the crystal structure of the Ca-α-sialon phosphor was decomposed.

The wavelength conversion member according to Example 22 emitted light when irradiated with excitation light. In the wavelength conversion member according to Example 22, the secondary firing temperature of the HIP treatment is as high as 1600° C. Therefore, the Ca-α-sialon phosphor, which is an oxynitride, reacts with the alumina, which is an oxide. It is presumed that the crystal structure of the Ca-α-sialon phosphor was partially decomposed, and although the relative density was relatively high at 97.5%, the relative emission intensity was 119.4%.

As shown in Table 3, the first sintered bodies according to Comparative Examples 1 to 5, in which the Ca-α-sialon phosphor was primarily fired together with an oxide other than alumina, all had relative densities of 71.0%. and did not emit light even when irradiated with excitation light.

The appearance of the wavelength conversion member according to Example 3 was bright orange as a whole, and maintained the original body color of the Ca-α-sialon phosphor. As shown in FIG. 3, in the appearance of the wavelength conversion member according to Example 3, color unevenness could not be confirmed, and the color was uniform overall. It was confirmed that the phosphor was not altered.

The appearance of the wavelength conversion member according to Example 12 was brighter as a whole, darker orange than that of Example 3, and maintained the original body color of the Ca-α-sialon phosphor. The reason why the appearance of the wavelength conversion member according to Example 12 is brighter than that of the wavelength conversion member according to Example 3 and looks dark orange is that the second sintered body 12 obtained by secondary firing by HIP treatment. This is thought to be because the densification progressed and the transparency increased. As shown in FIG. 4, in the appearance of the wavelength conversion member according to Example 12, no color unevenness could be confirmed, and the color was uniform as a whole. It was confirmed that the phosphor was not altered.

The appearance of the first sintered body according to Comparative Example 5 was changed to whitish as a whole and blackish in some places, and did not maintain the original orange color of the Ca-α-sialon phosphor. As shown in FIG. 5, in the appearance of the first sintered body according to Comparative Example 5, it is possible to confirm that the color unevenness that has turned blackish in places is confirmed, and it is presumed that the Ca-α-sialon phosphor has been altered by the primary firing. rice field.

In Examples 23 to 41, wavelength conversion members made of a first sintered body containing a Ca-α-sialon phosphor, a YAG-based phosphor, and alumina were manufactured. In Comparative Examples 6 to 9, first sintered bodies containing YAG phosphor and alumina, but not containing Ca-α-sialon phosphor were produced.

Production of YAG phosphor Yttrium oxide (Y ₂ O ₃ ), gadolinium oxide (Gd ₂ O ₃ ), cerium oxide (CeO ₂ ), and aluminum oxide (Al ₂ O ₃ ) were weighed so as to obtain the desired composition. and mixed to obtain a raw material mixture. Barium fluoride (BaF ₂ ) was added as a flux to the raw material mixture, and the raw material mixture and the flux were further mixed in a ball mill. This mixture was placed in an alumina crucible and heat-treated at 1500° C. for 10 hours in a reducing atmosphere to obtain a fired product. The baked product is dispersed in pure water, and while vibrating through a sieve, the solvent (pure water) is passed through a wet sieve, then dehydrated, dried, passed through a dry sieve, and classified. Then, a yttrium aluminum garnet (hereinafter also referred to as “YAG”) phosphor was obtained. The average particle size (Fisher sub-sieve sizer's number) of the YAG phosphor was measured by the FSSS method in the same manner as in Example 1 for measuring the average particle size of the α-alumina particles. The average particle size of the YAG phosphor was 5 μm.

Composition Analysis of YAG Phosphor For the YAG phosphor obtained, each element (Y , Gd, Ce, Al) were measured, and the molar ratio of each element in the composition of the YAG phosphor was calculated from the mass percentage value of each element. The molar ratio of Y, Gd, and Ce was calculated based on the measured Al molar ratio of 5 and the Al molar ratio of 5 as a reference. _{The composition ratio of} the YAG phosphor was ( _{Y0.575Gd0.400Ce0.025} ) _3Al5O12 .

Example 23
Powder mixing step 10 parts by mass of the obtained YAG phosphor represented by (Y _0.575 Gd _0.400 Ce _0.025 ) ₃ Al ₅ O ₁₂ having an average particle diameter of 5 μm measured by the FSSS method (for molding 10% by mass with respect to 100% by mass of the mixed powder) and a Ca-α-sialon phosphor with an average particle size of 13.0 μm measured by a laser diffraction scattering particle size distribution measurement method (product name: Aronbright variety YL-600 , manufactured by Denka Co., Ltd.) with 3 parts by mass (3% by mass of Ca-α-sialon phosphor with respect to 100% by mass of mixed powder for molding), and an average particle size of 0.5 μm measured by the FSSS method. 87 parts by mass of α-alumina particles (product name: AA03, manufactured by Sumitomo Chemical Co., Ltd., alumina purity 99.5% by mass) were weighed and mixed using a mortar and pestle to obtain a mixed powder for a compact. Got ready. In Tables 4 to 8, the Ca-α-sialon phosphor content (% by mass) indicates the mass ratio of the Ca-α-sialon phosphor charged with respect to 100% by mass of the mixed powder for the molded body. In Tables 4 to 8, the YAG phosphor content (% by mass) indicates the mass ratio of the YAG phosphor charged with respect to 100% by mass of the mixed powder for the molded body. In Tables 4 to 8, the content of alumina particles in each example and each comparative example is the content (% by mass) of the Ca-α-sialon phosphor from 100% by mass of the mixed powder for the molded body and the YAG fluorescence It is the remainder after subtracting the total amount of the body content (% by mass).

Molded body preparation step A mold was filled with the mixed powder for the molded body, and a cylindrical molded body with a diameter of 17.0 mm and a thickness of 10 mm was formed at a pressure of 4.6 MPa (46.9 kgf/cm ² ). . The resulting compact was placed in a packaging container, vacuum-packaged, and subjected to CIP treatment at 176 MPa using water as a pressure medium using a cold isostatic press (CIP) apparatus (manufactured by KOBELCO).

Primary Firing Step The obtained molded body is held in a firing furnace (manufactured by Fuji Dempa Kogyo Co., Ltd.) in a nitrogen gas atmosphere (nitrogen: 99% by volume or more) at a temperature of 0.9 MPa and 1300 ° C. for 6 hours, followed by primary firing. was performed to obtain a first sintered body. The obtained first sintered body was used as a wavelength conversion member according to Example 23. In Examples 23 to 41, the content (% by mass) of the Ca-α-sialon phosphor in the wavelength conversion member made of the first sintered body was Ca-α with respect to 100% by mass of the mixed powder for the compact. - The content (% by mass) of the YAG phosphor is almost equal to the mass ratio of the YAG phosphor with respect to 100% by mass of the mixed powder for the molding. Further, in Comparative Examples 6 to 9, the content (% by mass) of the YAG phosphor in the first sintered body was approximately the mass ratio of the YAG phosphor charged to 100% by mass of the mixed powder for the compact. equal.

Example 24
A first sintered body was obtained in the same manner as in Example 23, except that the firing temperature in the primary firing step was set to 1400 ° C., and the obtained first sintered body was used for wavelength conversion according to Example 24. It was used as a member.

Example 25
A first sintered body was obtained in the same manner as in Example 23, except that the firing temperature in the primary firing step was set to 1450 ° C., and the obtained first sintered body was used for wavelength conversion according to Example 25. It was used as a member.

Example 26
A first sintered body was obtained in the same manner as in Example 23, except that the firing temperature in the primary firing step was set to 1500 ° C., and the obtained first sintered body was used for wavelength conversion according to Example 26. It was used as a member.

Example 27
Same as Example 25, except that mixed powder for molding was prepared by mixing 5 parts by mass of YAG phosphor, 1 part by mass of Ca-α-sialon phosphor, and 94 parts by mass of α-alumina particles. Then, a first sintered body was obtained, and the obtained first sintered body was used as a wavelength conversion member according to Example 27.

Example 28
A first sintered body was prepared in the same manner as in Example 27, except that the YAG phosphor was 5 parts by mass, the Ca-α-sialon phosphor was 3 parts by mass, and the α-alumina particles were 92 parts by mass. The obtained first sintered body was used as a wavelength conversion member according to Example 28.

Example 29
A first sintered body was prepared in the same manner as in Example 27, except that the YAG phosphor was 5 parts by mass, the Ca-α-sialon phosphor was 10 parts by mass, and the α-alumina particles were 85 parts by mass. The obtained first sintered body was used as a wavelength conversion member according to Example 29.

Example 30
Example 27, except that mixed powder for molding was prepared by mixing 5 parts by mass of YAG phosphor, 20 parts by mass of Ca-α-sialon phosphor, and 75 parts by mass of α-alumina particles. Similarly, a first sintered body was obtained, and the obtained first sintered body was used as a wavelength conversion member according to Example 30.

Comparative example 6
A first sintered body was obtained in the same manner as in Example 27, except that the YAG phosphor was 5 parts by mass and the α-alumina particles were 95 parts by mass. A wavelength conversion member according to Comparative Example 6 was obtained. The wavelength conversion member according to Comparative Example 6 does not contain the Ca-α-sialon phosphor.

Example 31
Example 25 except that mixed powder for molding was prepared by mixing 10 parts by mass of YAG phosphor, 1 part by mass of Ca-α-sialon phosphor, and 89 parts by mass of α-alumina particles. Similarly, a first sintered body was obtained, and the obtained first sintered body was used as a wavelength conversion member according to Example 31.

Example 32
A first sintered body was prepared in the same manner as in Example 31, except that the YAG phosphor was 10 parts by mass, the Ca-α-sialon phosphor was 10 parts by mass, and the α-alumina particles were 80 parts by mass. The obtained first sintered body was used as a wavelength conversion member according to Example 32.

Example 33
A first sintered body was prepared in the same manner as in Example 31, except that the YAG phosphor was 10 parts by mass, the Ca-α-sialon phosphor was 20 parts by mass, and the α-alumina particles were 70 parts by mass. The obtained first sintered body was used as a wavelength conversion member according to Example 33.

Comparative example 7
A first sintered body was obtained in the same manner as in Example 31, except that the YAG phosphor was 10 parts by mass and the α-alumina particles were 90 parts by mass. A wavelength conversion member according to Comparative Example 7 was obtained. The wavelength conversion member according to Comparative Example 7 does not contain the Ca-α-sialon phosphor.

Example 34
Example 25, except that mixed powder for molding was prepared by mixing 20 parts by mass of YAG phosphor, 1 part by mass of Ca-α-sialon phosphor, and 79 parts by mass of α-alumina particles. Similarly, a first sintered body was obtained, and the obtained first sintered body was used as a wavelength conversion member according to Example 34.

Example 35
Example 34, except that mixed powder for molding was prepared by mixing 20 parts by mass of YAG phosphor, 3 parts by mass of Ca-α-sialon phosphor, and 77 parts by mass of α-alumina particles. Similarly, a first sintered body was obtained, and the obtained first sintered body was used as a wavelength conversion member according to Example 35.

Example 36
A first sintered body was prepared in the same manner as in Example 34, except that the YAG phosphor was 20 parts by mass, the Ca-α-sialon phosphor was 10 parts by mass, and the α-alumina particles were 70 parts by mass. The obtained first sintered body was used as a wavelength conversion member according to Example 36.

Example 37
A first sintered body was prepared in the same manner as in Example 34, except that the YAG phosphor was 20 parts by mass, the Ca-α-sialon phosphor was 20 parts by mass, and the α-alumina particles were 60 parts by mass. The obtained first sintered body was used as a wavelength conversion member according to Example 37.

Comparative example 8
A first sintered body was obtained in the same manner as in Example 34, except that the YAG phosphor was 20 parts by mass and the α-alumina particles were 80 parts by mass. A wavelength conversion member according to Comparative Example 8 was obtained. The wavelength conversion member according to Comparative Example 8 does not contain the Ca-α-sialon phosphor.

Example 38
Example 25 except that mixed powder for molding was prepared by mixing 30 parts by mass of YAG phosphor, 1 part by mass of Ca-α-sialon phosphor, and 69 parts by mass of α-alumina particles. Similarly, a first sintered body was obtained, and the obtained first sintered body was used as a wavelength conversion member according to Example 38.

Example 39
A first sintered body was prepared in the same manner as in Example 38, except that the YAG phosphor was 30 parts by mass, the Ca-α-sialon phosphor was 3 parts by mass, and the α-alumina particles were 67 parts by mass. The obtained first sintered body was used as a wavelength conversion member according to Example 39.

Example 40
A first sintered body was prepared in the same manner as in Example 38, except that the YAG phosphor was 30 parts by mass, the Ca-α-sialon phosphor was 10 parts by mass, and the α-alumina particles were 60 parts by mass. The obtained first sintered body was used as a wavelength conversion member according to Example 40.

Example 41
A first sintered body was prepared in the same manner as in Example 38, except that the YAG phosphor was 30 parts by mass, the Ca-α-sialon phosphor was 20 parts by mass, and the α-alumina particles were 50 parts by mass. The obtained first sintered body was used as a wavelength conversion member according to Example 41.

Comparative example 9
A first sintered body was obtained in the same manner as in Example 38, except that the YAG phosphor was 30 parts by mass and the α-alumina particles were 70 parts by mass. A wavelength conversion member according to Comparative Example 9 was obtained. The wavelength conversion member according to Comparative Example 9 does not contain the Ca-α-sialon phosphor.

Measurement of Relative Density of First Sintered Body In Examples 23 to 41 and Comparative Examples 6 to 9, the relative density of each first sintered body was measured based on the following formulas (1) to (3). Table 4 shows the relative densities of the first sintered bodies of Examples 23-26. Table 5 shows the relative densities of the first sintered bodies of Examples 27 to 30 and Comparative Example 6. Table 6 shows the relative densities of the first sintered bodies of Examples 31 to 33 and Comparative Example 7. Table 7 shows the relative densities of the first sintered bodies of Examples 34 to 37 and Comparative Example 8. Table 8 shows the relative densities of the first sintered bodies of Examples 38 to 41 and Comparative Example 9.
Relative density was measured by the following formula (1).
Relative density (%) = (apparent density of first sintered body / true density of first sintered body) x 100 (1)

The true density of the first sintered body was calculated from the following formula (2-2). The true density of the α-alumina particles used in each example and comparative example was 3.98 g/cm ³ . The true density of the Ca-α-sialon phosphor was 3.22 g/cm ³ . The true density of the YAG phosphor was 4.77 g/cm ³ . The true density of the YAG phosphor was measured using a dry automatic densitometer (trade name: ACUBIC 1330, manufactured by Shimadzu Corporation).
True density of the first sintered body = (mass ratio of Ca-α-sialon phosphor to 100% by mass of mixed powder for compact × true density of Ca-α-sialon phosphor) + (for compact Mass ratio of YAG phosphor with respect to 100% by mass of mixed powder x true density of YAG phosphor) + (mass ratio of alumina particles with respect to 100% by mass of mixed powder for molded body x true density of alumina particles) (2-2 )

The apparent density of the first sintered body was calculated by the following formula (3).
Apparent density of first sintered body = Mass of first sintered body / Volume of first sintered body obtained by Archimedes method (3)

Measurement of Relative Emission Intensity and Chromaticity A wavelength conversion member made of the first sintered body of each example and comparative example was cut to a thickness of 300 μm using a wire saw to form a sample. Using an LED chip made of a nitride semiconductor having an emission peak wavelength of 455 nm as a light source, the sample of the wavelength conversion member is irradiated with light from this light source, and the light from the light source is received from each sample to obtain a wavelength of 430 nm or more and 800 nm. The emission intensity and chromaticity (x value and y value in CIE chromaticity coordinates) of the emission peak wavelength in the following wavelength range were measured using a spectrofluorometer. Some of the wavelength conversion members having relative densities exceeding 90% transmit blue light emitted from the light source. The chromaticities of Examples 23 to 41 and Comparative Examples 6 to 9 were measured by excluding the emission spectrum of blue light in the range of 490 nm or less among the emission spectra in the wavelength range of 430 nm or more and 800 nm or less obtained from each sample. Chromaticity (x value, y value).

Table 4 shows the relative emission intensity and chromaticity (x value, y value) of the first sintered bodies, which are the wavelength conversion members according to Examples 23 to 26. Among the first sintered bodies of Examples 23 to 26, the emission intensity of the first sintered body of Example 25, whose relative density is closest to the value of 90%, is set to 100%, and of Examples 23 to 26. The emission intensity of the first sintered body was expressed as relative emission intensity (%).

Table 5 shows the relative emission intensity and chromaticity (x value, y value) of the first sintered bodies in the wavelength conversion members according to Examples 27 to 30 and Comparative Example 6. Among the first sintered bodies of Examples 27 to 30 and Comparative Example 6, the emission intensity of the first sintered body of Example 30, whose relative density is closest to the value of 90%, is set to 100%. The emission intensities of the first sintered bodies of Nos. 27 to 30 and Comparative Example 6 were expressed as relative emission intensities (%).

Table 6 shows the relative emission intensity and chromaticity (x value, y value) of the first sintered bodies, which are the wavelength conversion members according to Examples 31 to 33 and Comparative Example 7. Among the first sintered bodies of Examples 31 to 33 and Comparative Example 7, the emission intensity of the first sintered body of Example 33, whose relative density is closest to the value of 90%, is set to 100%. The luminescence intensity of the first sintered bodies of Nos. 31 to 33 and Comparative Example 7 was expressed as relative luminescence intensity (%).

Table 7 shows the relative emission intensity and chromaticity (x value, y value) of the first sintered bodies, which are the wavelength conversion members according to Examples 34 to 37 and Comparative Example 8. Among the first sintered bodies of Examples 34 to 37 and Comparative Example 8, the emission intensity of the first sintered body of Example 37, whose relative density is closest to the value of 90%, is set to 100%. The luminescence intensity of the first sintered bodies of Nos. 34 to 37 and Comparative Example 8 was expressed as relative luminescence intensity (%).

Table 8 shows the relative emission intensity and chromaticity (x value, y value) of the first sintered bodies, which are the wavelength conversion members according to Examples 38 to 41 and Comparative Example 9. Among the first sintered bodies of Examples 38 to 41 and Comparative Example 9, the emission intensity of the first sintered body of Example 40, whose relative density is closest to the value of 90%, is set to 100%. The luminescence intensity of the first sintered bodies of 38 to 41 and Comparative Example 9 was expressed as relative luminescence intensity (%).

FIG. 6 is a diagram plotting the chromaticity (x value, y value) of the wavelength conversion members made of the first sintered bodies according to Examples 23 to 26 on the CIE chromaticity coordinates. FIG. 7 shows the wavelength conversion members made of the first sintered bodies according to Examples 27 to 30 and the chromaticity (x value, y value) of the first sintered body of Comparative Example 6 on the CIE chromaticity coordinates. It is a plotted figure.

As shown in Table 4, the wavelength conversion members according to Examples 23 to 26 consist of first sintered bodies obtained by changing the primary firing temperature from 1300°C to 1500°C, and the primary firing temperature is The higher, the higher the relative density and the higher the relative emission intensity.

As shown in Table 4 and FIG. 6, the chromaticity of the wavelength conversion member according to Example 26 shifted to the short wavelength side compared to the wavelength conversion members according to Examples 23-25. Since the wavelength conversion member of Example 26 had a high relative density of 93.1%, the blue light emitted from the light source was clearly transmitted. The chromaticity x value and y value of each example shown in FIG. 6 are the chromaticities measured excluding the blue light emitted from the light source. The reason for the migration is that the primary firing temperature is relatively high at 1500° C., and the crystal structure of the Ca-α-sialon phosphor is partially decomposed and deteriorated by a compound containing a trace amount of fluorine, for example, contained in the YAG phosphor. , because only the YAG phosphor emitted light upon irradiation with the excitation light.

As shown in Table 5, in the wavelength conversion members according to Examples 27 to 30, when the content of the YAG phosphor is 5% by mass, the Ca-α-sialon phosphor is in the range of 1 to 10% by mass. The increase resulted in higher relative density and relative emission intensity. Like the wavelength conversion members according to Examples 27 to 30, the total content of the Ca-α-sialon phosphor and the YAG phosphor is in the range of 0.1% by mass or more and 70% by mass or less, and Ca-α- If the content of the sialon phosphor is in the range of 0.1% by mass or more and 40% by mass or less, the relative density is 80% or more, and the emission peak wavelength is 430 nm or more and 800 nm or less by irradiation with excitation light having an emission peak wavelength of 455 nm. It emitted light having an emission peak wavelength in the wavelength range and could be used as a wavelength conversion member.

As shown in Table 5 and FIG. 7, the wavelength conversion members according to Examples 27 to 30 had an emission peak wavelength in the wavelength range of 430 nm or more and 800 nm or less by irradiation with excitation light having an emission peak wavelength of 455 nm, Compared with Comparative Example 6, it could be used as a wavelength conversion member that emits light with chromaticity on the long wavelength side and emits light in a desired color tone.

Since the wavelength conversion member of Comparative Example 6 had a high relative density of 90.3%, the blue light emitted from the light source was clearly transmitted. The chromaticity x value and y value of each example and comparative example shown in Table 5 and FIG. Since the body does not contain the Ca-α-sialon phosphor, compared to the wavelength conversion members made of the first sintered bodies according to Examples 27 to 30, the chromaticity (x value, y value ).

As shown in Table 6, in the wavelength conversion members according to Examples 31 to 33, when the content of the YAG phosphor is 10% by mass, the Ca-α-sialon phosphor is in the range of 1 to 20% by mass. The increase resulted in higher relative density and relative emission intensity. Like the wavelength conversion members according to Examples 31 to 33, the total content of the Ca-α-sialon phosphor and the YAG phosphor is in the range of 0.1% by mass or more and 70% by mass or less, and the Ca-α- If the content of the sialon phosphor is in the range of 0.1% by mass or more and 40% by mass or less, the relative density is 80% or more, and the emission peak wavelength is 430 nm or more and 800 nm or less by irradiation with excitation light having an emission peak wavelength of 455 nm. It emitted light having an emission peak wavelength in the wavelength range, emitted light with chromaticity on the longer wavelength side compared to Comparative Example 7, and could be used as a wavelength conversion member that emits light in a desired color tone.

As shown in Table 6, since the first sintered body of Comparative Example 7 does not contain the Ca-α-sialon phosphor, the wavelength conversion member composed of the first sintered bodies of Examples 31 to 33 , emitted light with chromaticity (x value, y value) on the short wavelength side.

As shown in Table 7, in the wavelength conversion members according to Examples 34 to 37, when the content of the YAG phosphor is 20% by mass, the Ca-α-sialon phosphor is in the range of 1 to 10% by mass. The increase resulted in higher relative density and relative emission intensity. Like the wavelength conversion members according to Examples 34 to 37, the total content of the Ca-α-sialon phosphor and the YAG phosphor is in the range of 0.1% by mass or more and 70% by mass or less, and Ca-α- If the content of the sialon phosphor is in the range of 0.1% by mass or more and 40% by mass or less, the relative density is 80% or more, and the emission peak wavelength is 430 nm or more and 800 nm or less by irradiation with excitation light having an emission peak wavelength of 455 nm. It emitted light having an emission peak wavelength in the wavelength range, emitted light with chromaticity on the longer wavelength side compared to Comparative Example 8, and could be used as a wavelength conversion member that emits light in a desired color tone.

As shown in Table 7, since the first sintered body of Comparative Example 8 does not contain the Ca-α-sialon phosphor, the wavelength conversion member composed of the first sintered bodies of Examples 34 to 37 , emitted light with chromaticity (x value, y value) on the short wavelength side.

As shown in Table 8, in the wavelength conversion members according to Examples 38 to 41, when the content of the YAG phosphor is 30% by mass, the Ca-α-sialon phosphor is in the range of 1 to 10% by mass. As it increased, the relative density increased. Further, in the wavelength conversion members according to Examples 38 to 41, when the content of the YAG phosphor is 30% by mass and the Ca-α-sialon phosphor is increased in the range of 1 to 20% by mass, the relative emission intensity became higher. Like the wavelength conversion members according to Examples 38 to 41, the total content of the Ca-α-sialon phosphor and the YAG phosphor is in the range of 0.1% by mass or more and 70% by mass or less, and Ca-α- If the content of the sialon phosphor is in the range of 0.1% by mass or more and 40% by mass or less, the relative density is 80% or more, and the emission peak wavelength is 430 nm or more and 800 nm or less by irradiation with excitation light having an emission peak wavelength of 455 nm. It has an emission peak wavelength in the wavelength range, emits light with chromaticity on the longer wavelength side than Comparative Example 9, and can be used as a wavelength conversion member that emits light in a desired color tone.

As shown in Table 8, since the first sintered body of Comparative Example 9 does not contain the Ca-α-sialon phosphor, the wavelength conversion member composed of the first sintered bodies of Examples 38 to 41 , emitted light with chromaticity (x value, y value) on the short wavelength side.

The wavelength conversion member according to the present disclosure emits light when irradiated with excitation light, and can be used as a material for a wavelength conversion member and a solid scintillator capable of converting the wavelength of light emitted from an LED or LD.

Claims (14)

Preparing a molded body obtained by molding a mixed powder containing a Ca- α-sialon phosphor and alumina particles, and primary firing the molded body at a temperature in the range of 1000 ° C. or higher and 1600 ° C. or lower to obtain a first obtaining a sintered body,
In the mixed powder, the content of the Ca- α-sialon phosphor is in the range of 0.1% by mass or more and 40% by mass or less with respect to 100% by mass of the mixed powder, and the mixed powder 100 The remainder excluding the Ca- α-sialon phosphor from the mass% is the alumina particles,
The content of the alumina particles is in the range of 60% by mass or more and 99.9% by mass or less,
Using a mold press, the mixed powder is molded at a pressure of 3 MPa or more and 50 MPa or less, and the mixed powder is cold isostatically pressed (CIP) at a pressure of 50 MPa or more and 250 MPa or less, and the molding is performed. prepare the body
A method for producing a wavelength conversion member , wherein the first sintered body has a relative density of 80% or more . preparing a molded body obtained by molding a mixed powder containing a Ca- α-sialon phosphor, alumina particles, and an yttrium aluminum garnet phosphor; Primary firing at a temperature to obtain a first sintered body,
In the mixed powder, the content of the Ca- α-sialon phosphor is in the range of 0.1% by mass or more and 40% by mass or less with respect to 100% by mass of the mixed powder, and the Ca- α- The total amount of the sialon phosphor and the yttrium aluminum garnet phosphor is in the range of 0.1% by mass or more and 70% by mass or less, and the content of the Ca- α-sialon phosphor is from 100% by mass of the mixed powder and the remainder excluding the yttrium-aluminum garnet-based phosphor is the alumina particles, and the content of the alumina particles is in the range of 30% by mass or more and 99.9% by mass or less,
Using a mold press, the mixed powder is molded at a pressure of 3 MPa or more and 50 MPa or less, and the mixed powder is cold isostatically pressed (CIP) at a pressure of 50 MPa or more and 250 MPa or less, and the molding is performed. prepare the body
A method for producing a wavelength conversion member , wherein the first sintered body has a relative density of 80% or more . 3. The method for producing a wavelength conversion member according to claim 1, wherein the Ca- α-sialon phosphor has a composition represented by the following formula (I) .
Cav (Si,Al) ₁₂ (O,N) ₁₆ :Eu ₍ I)
(In formula (I), v is a number that satisfies 0<v≦2.) The second sintered body is obtained by secondarily firing the first sintered body at a temperature in the range of 1000 ° C. or higher and 1600 ° C. or lower by hot isostatic pressing (HIP) treatment. 4. A method for manufacturing a wavelength conversion member according to 1 or 3. The second sintered body is obtained by secondarily firing the first sintered body at a temperature in the range of 1000 ° C. or higher and 1500 ° C. or lower by hot isostatic pressing (HIP) treatment. 3. The method for manufacturing the wavelength conversion member according to 2. The method for manufacturing a wavelength conversion member according to any one of claims 1, 3 to 4 , wherein the primary firing temperature is in the range of 1200°C or higher and 1570°C or lower. The method for manufacturing a wavelength conversion member according to claim 2 or 5, wherein the primary firing temperature is in the range of 1200°C or higher and 1450°C or lower. 8. The method for producing a wavelength conversion member according to claim 1, wherein the Ca- α-sialon phosphor has an average particle diameter in the range of 2 μm or more and 30 μm or less. The method for manufacturing a wavelength conversion member according to any one of claims 1 to 8 , wherein the alumina particles have an average particle diameter in the range of 0.1 µm or more and 1.3 µm or less. The method for producing a wavelength conversion member according to any one of claims 1 to 9 , wherein the alumina particles have an alumina purity of 99.0% by mass or more. The method for manufacturing a wavelength conversion member according to claim 4 or 5 , wherein the second sintered body has a relative density of 90% or more. Ca- α-sialon phosphor and alumina, the content of the Ca- α-sialon phosphor is in the range of 0.1% by mass or more and 40% by mass or less, the balance being alumina and voids, A wavelength conversion member having a density of 80% or more . A Ca- α-sialon phosphor, alumina, and an yttrium aluminum garnet-based phosphor are included, and the content of the Ca- α-sialon phosphor is in the range of 0.1% by mass or more and 40% by mass or less. , the total content of the yttrium aluminum garnet phosphor and the Ca- α-sialon phosphor is 0.1% by mass or more and 70% by mass or less, and the balance is the alumina and voids , and the relative density is 80% or more. There is a wavelength conversion member. The wavelength conversion member according to claim 12 or 13 , wherein the Ca- α-sialon phosphor has a composition represented by the following formula (I) .
Cav (Si,Al) ₁₂ (O,N) ₁₆ :Eu ₍ I)
(In formula (I), v is a number that satisfies 0<v≦2.)

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