α-type sialon phosphor and light-emitting device

Abstract

An α-type sialon phosphor represented by the general formula: (Cax, Euy)(Si12-(m+n)Alm+n)(OnN16-n), having an average linear expansion coefficient α´ of 4.2 ppm / ℃ or higher and 4.6 ppm / ℃ or lower at 25–900℃. In the general formula, 0 <x<2.0, 0<y≤0.5, 0.3≤x+y≤2.0, 0<m≤4.0, 0<n≤3.0이다.

Description

Technology Field The present invention relates to an α-type sialon phosphor and a light-emitting device. Background Technology α-type sialon phosphors, which are revitalized with rare earth elements such as Eu, can efficiently convert blue light into long-wavelength light. Therefore, they are applied, for example, to wavelength conversion components of white LEDs. α-type sialon phosphors typically have a structure in which the Si-N bonds of α-type silicon nitride crystals are partially replaced by Al-N and Al-O bonds, and specific elements (Ca, and lanthanide metals excluding Li, Mg, Y, or La and Ce) are interstitially dissolved within the crystal lattice to maintain electrical neutrality. Fluorescence properties are exhibited by making some of the interstitially dissolved elements rare earth elements that serve as emission centers. In particular, α-type sialon phosphors in which Ca is dissolved and a portion thereof is substituted with Eu are excited relatively efficiently over a wide wavelength range from ultraviolet to blue, exhibiting yellow or orange emission. Various attempts have been proposed to further improve the fluorescence properties of α-type sialon phosphors (e.g., Patent Documents 1–3, etc.). Prior art literature Patent Document 1: Japanese Published Patent Application No. 2009-96882 Patent Document 2: Japanese Patent Publication No. 6667025 Patent Document 3: Japanese Patent Publication No. 6785333 The problem to be solved With the widespread adoption of white LEDs, the performance requirements for α-type sialon phosphors are becoming increasingly high. The inventors have conducted various studies to obtain an α-type sialon phosphor having improved luminescence characteristics. means of solving the problem The inventors have completed the invention provided below through various reviews. 1. An α-type sialon phosphor represented by the general formula below, having an average linear expansion coefficient α´ at 25–900°C of 4.2 ppm / °C or more and 4.6 ppm / °C or less. General formula: (Ca x , Eu y )(Si 12-(m+n) Al m+n )(O n N 16-n ) In the above general formula, x, y, m and n satisfy the following. 0 <x<2.0 0 <y≤0.5 0.3≤x+y≤2.0 0 <m≤4.0 0 <n≤3.0 2. As an α-type sialon phosphor described in 1, 2.5≤m≤4.0 and 0 <n≤0.5인 α형 사이알론 형광체. 3. As an α-type sialon phosphor described in 1. or 2., α-type sialon phosphor having an average linear expansion coefficient of 25–300°C as α1’ and an average linear expansion coefficient of 700–900°C as α2’, wherein α2’ / α1’ is 1.3–1.8. 4. As an α-type sialon phosphor described in any one of 1 to 3, At 25℃, the lattice constant a of the unit cell 25 α is between 7.900 Å and 7.960 Å, and the lattice constant c 25 α-type sialon phosphor with a diameter of 5.720 Å or more and 5.780 Å or less. 5. As an α-type sialon phosphor described in any one of 1 to 4, At 25℃, the lattice volume V of the unit cell 25 308Å 3 Above 320Å 3 α-type sialon phosphor with less than 100 parts. 6. As an α-type sialon phosphor described in any one of 1 to 5, In the above general formula, x, y, m and n are α-type sialon phosphors satisfying the following. 1.3≤x<2.0 0.01≤y≤0.1 1.3≤x+y≤2.0 2.8≤m<4.0 0.1≤n≤0.27 7. A light-emitting element and, A light-emitting device comprising an α-type sialon phosphor described in any one of 1 to 6, and a wavelength conversion unit that converts light emitted from the light-emitting element into a long wavelength. Effects of the invention According to the present invention, an α-type sialon phosphor with improved luminescence properties is provided. Brief explanation of the drawing Figure 1 is a schematic cross-sectional view illustrating the structure of a light-emitting device. Specific details for implementing the invention Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Drawings are for illustrative purposes only. The shapes and dimensional ratios of each component in the drawings do not necessarily correspond to actual products. In the description of numerical ranges in this specification, the notation "X~Y" indicates X or more and Y or less, unless specifically explained otherwise. For example, "1~5 mass%" means "1 mass% or more and 5 mass% or less." α-type sialon fluorescence The α-type sialon phosphor of the present embodiment is, General formula: (Ca x , Eu y )(Si 12-(m+n) Al m+n )(O n N 16-n ) It appears as. In the above general formula, x, y, m and n satisfy the following. 0 <x<2.0 0 <y≤0.5 0.3≤x+y≤2.0 0 <m≤4.0 0 <n≤3.0 In addition, the average linear expansion coefficient α´ of the α-type sialon phosphor of the present embodiment at 25 to 900°C is 4.2 ppm / °C or higher and 4.6 ppm / °C or lower. The luminescence characteristics of the α-type sialon phosphor of the present embodiment are good. Although the reason for this is not necessarily clear, considering that m and n in the above general formula are within a specific numerical range and that the coefficient of thermal expansion is considered to be an indicator that may be correlated with the crystal structure, it is presumed that the α-type sialon phosphor of the present embodiment has a crystal structure that is easy to efficiently emit fluorescence. In this embodiment, the average linear expansion coefficient α´ can be obtained by measuring and analyzing the relationship between temperature and lattice constants, for example, as shown below [Example of a procedure for obtaining the average linear expansion coefficient α´]. For a detailed calculation method, please refer to the example described below. [An example of the procedure for calculating the average linear expansion coefficient α´] (1) X-ray diffraction measurements of α-type sialon phosphors are performed at several points within a temperature range of 25 to 900°C. (2) From the results of X-ray diffraction measurements, the lattice constant of the crystal in the phosphor at each temperature T is determined. In the case of an α-type sialon phosphor, the lattice constant a at each temperature T is T and c T Calculate . For reference, regarding the crystal structure of α-type sialon, the lattice constant b of the unit cell T is, a T It becomes the same value as. (3) Temperature T - Lattice constant a T , temperature T-lattice constant c TCreate a graph plotting each. Then, find the equation of the approximate line for each graph. The approximate line can be determined using the least squares method. (4) From the approximate line, the lattice constant a at 25°C 25 and c 25 , and, lattice constant a at 900°C 900 and c 900 Read these values. V of formula 1 below 25 consciousness and V 900 Substitute into the equation, and the lattice volume V at 25℃ 25 and lattice volume V at 900°C 900 Calculate the volume expansion rate β based on the equation of formula 2 below. [Mathematical Formula 1] [Mathematical Formula 2] (5) Calculate the average linear expansion coefficient α´ using the equation α´=β / 3. For reference, this equation α´=β / 3 is used to calculate the average linear expansion coefficient as a polycrystalline material, assuming the sample is an isotropic material. The α-type sialon phosphor of the present embodiment can be manufactured by using appropriate raw materials in appropriate amounts and employing appropriate manufacturing conditions. Regarding "using appropriate raw materials in appropriate amounts," the amount of raw materials can be adjusted to satisfy x, y, m, and n of the general formula described above. Regarding "appropriate manufacturing conditions," examples include an "annealing process" under an inert gas atmosphere such as nitrogen gas, which will be explained in detail later, and a "hydrogen annealing process" under a hydrogen gas atmosphere. By adopting appropriate manufacturing methods and conditions, the α-type sialon phosphor of the present embodiment can be manufactured. Conversely, if appropriate manufacturing methods and conditions are not adopted, there may be cases where the α-type sialon phosphor of the present embodiment cannot be obtained even if appropriate raw materials are used in appropriate amounts. 본 실시형태의 α형 사이알론 형광체에 관한 설명을 계속한다. ( General formula: (Ca x , Eu y )(Si 12-(m+n) Al m+n )(O n N 16-n Regarding ) x is 0 <x<2.0을 충족시키면 되고, 바람직하게는 1.0≤x<2.0이며, 보다 바람직하게는 1.3≤x<2.0이고, y is 0 <y<0.5를 충족시키면 되며, 바람직하게는 0.01≤y≤0.1이고, x+y는, 0.3≤x+y≤2.0을 충족시키면 되며, 바람직하게는 1.0≤x+y≤2.0, 보다 바람직하게는 1.3≤x+y≤2.0이고, m is 0 <m≤4.0을 충족시키면 되며, 바람직하게는 2.5≤m≤4.0, 보다 바람직하게는 2.8≤m≤4.0, 더 바람직하게는 2.8≤m<4.0이고, n is 0 <n≤3.0을 충족시키면 되며, 바람직하게는 0<n≤0.5, 보다 바람직하게는 0.1≤n≤0.4, 더 바람직하게는 0.1≤n≤0.27이다. 특히 바람직한 x, y, x+y, m 및 n의 수치 범위는 이하와 같다. 1.3≤x<2.0 0.01≤y≤0.1 1.3≤x+y≤2.0 2.8≤m<4.0 0.1≤n≤0.27 In some cases, the luminescence characteristics of the α-type sialon phosphor can be further enhanced by optimizing x, y, x+y, m, and n. In addition, in some cases, the average linear expansion coefficient α´ can be more appropriately controlled by optimizing x, y, x+y, m, and n. (Regarding lattice constant and lattice volume) The lattice constant a of the unit cell at 25°C of the α-type sialon phosphor of the present embodiment 25 is, preferably 7.900 Å or more and 7.960 Å or less, lattice constant c 25 is preferably between 5.720 Å and 5.780 Å. For reference, regarding the crystal structure of α-type sialon, the lattice constant b of the unit cell at 25°C is 25 is, a 25 It becomes the same value as. Also, the lattice volume V of the unit cell at 25°C of the α-type sialon phosphor of the present embodiment 25 is, preferably 308Å 3 Above 320Å 3 It is as follows. As described above, the α-type sialon of the present embodiment is presumed to have a crystal structure that is efficient at emitting fluorescence. The numerical range of these lattice constants is thought to reflect the "crystal structure that is efficient at emitting fluorescence." Each of the above values ​​can be obtained by the Pawley method. (Regarding the average linear expansion coefficient at low temperature and, the average linear expansion coefficient at high temperature) In the α-type sialon phosphor of the present embodiment, the average linear expansion coefficient at low temperature or the average linear expansion coefficient at high temperature may be within a suitable numerical range, thereby further improving the luminescence characteristics. Specifically, when the average linear expansion rate of the α-type sialon phosphor of the present embodiment is set to α1´ at 25 to 300°C and the average linear expansion rate at 700 to 900°C is set to α2´, α2´ / α1´ is preferably 1.3 to 1.8, more preferably 1.3 to 1.7, and even more preferably 1.3 to 1.6. The method for calculating α1´ and α2´ will be explained in detail below. · Method for calculating the average linear expansion coefficient α1´ at 25~300℃ (1) Lattice constant a obtained by the Pawley method 25 , c 25 By substituting the value of (the definitions of these symbols are the same as above) into the following equation, the lattice volume V at 25℃ 25 Calculate. For reference, since the crystal structure of α-type sialon is hexagonal, the lattice volume is expressed by this equation. [Mathematical Formula 3] (2) Likewise, lattice constant a at 300℃ 300 , c 300 Using the value of, the lattice volume V at 300℃ 300 Produces. (3) The volume expansion rate β1 is calculated according to the following formula. ΔT is 300℃-25℃=275℃. [Mathematical Formula 4] (4) Assuming the sample is an isotropic material, the average linear expansion coefficient α1´ as a polycrystalline material is calculated using the formula α1´=β1 / 3. · Method for calculating the average linear expansion coefficient α2´ at 700~900℃ (1) Lattice constant a at 700°C according to the Pawley method 700 , c 700 Calculate the value of. The calculated value Substituting into the following equation, the lattice volume V at 700℃ 700Calculate. For reference, since the crystal structure of α-type sialon is hexagonal, the lattice volume is expressed by this equation. [Mathematical Formula 5] (2) Likewise, the lattice constant a at 900℃ 900 , c 900 Calculate the value of . And, the lattice volume V at 900℃ 900 Produces. (3) Calculate the volume expansion rate β2 using the following formula. ΔT is 900℃-700℃=200℃. [Mathematical Formula 6] (4) Assuming the sample is an isotropic material, the average linear expansion coefficient α2´ as a polycrystalline material is calculated using the formula α2´=β2 / 3. (Regarding the nature) The α-type sialon phosphor of the present embodiment is typically in powder form. The lower limit of the median diameter D50 of the powdered α-type sialon phosphor particles is preferably 1 μm or more, more preferably 5 μm or more, and more preferably 10 μm or more. In addition, the upper limit of the median diameter D50 is preferably 30 μm or less, and more preferably 20 μm or less. That is, the median diameter D50 is preferably 1 to 30 μm, more preferably 5 to 30 μm, and even more preferably 10 to 20 μm. By making the median diameter D50 5 μm or more, the transparency of the composite described below can be further increased. On the other hand, by making the median diameter D50 30 μm or less, chipping can be suppressed when the composite is cut and processed with a die cutter, etc. The median diameter D50 can be obtained by the laser diffraction scattering method in accordance with JIS R1629:1997. For more specific measurement methods, please refer to the examples described below. Method for manufacturing α-type sialon phosphors As described above, the α-type sialon phosphor of the present embodiment can be manufactured by using appropriate raw materials in appropriate amounts and employing appropriate manufacturing conditions. An example of a manufacturing method is described below. · Mixing of raw materials First, raw materials containing elements that constitute α-type sialon phosphor particles containing Eu are mixed. In α-type sialon phosphor particles with a low oxygen content synthesized using calcium nitride as a calcium raw material, calcium is dissolved in high concentrations. In particular, when the concentration of Ca is high, a phosphor is obtained having an emission peak wavelength on the higher wavelength side (590 nm or more, more specifically 590 nm or more and 610 nm or less, and even more specifically 592 nm or more and 608 nm or less) compared to conventional compositions using oxide raw materials. Examples of raw material powders other than those mentioned above include silicon nitride, aluminum nitride, and Eu compounds. Examples of Eu compounds include europium oxide, compounds that become europium oxide after heating, and europium nitride. Europium nitride, which can reduce the amount of oxygen in the system, is preferred. A suitable amount of pre-synthesized α-type sialon phosphor particles may be added to the raw material powder. These phosphor particles serve as a starting point for particle growth, and in some cases, α-type sialon phosphor particles with a relatively large uniaxial diameter can be obtained. In addition, the particle shape may be controlled by changing the shape of the added α-type sialon particles. Methods for mixing each raw material include dry mixing and wet mixing in an inert solvent that does not substantially react with each component of the raw material, followed by the removal of the solvent. Mixing devices include V-type mixers, locking mixers, ball mills, and vibrating mills. Regarding the mixing of calcium nitride, which is unstable in the atmosphere, it is preferable to perform the mixing in a glove box with an inert atmosphere, as its hydrolysis or oxidation affects the properties of the synthesized product. · Heat treatment (sintering) The powder obtained by mixing (hereinafter simply referred to as raw material powder) is filled into a container made of a material having low reactivity with the raw material and the phosphor being synthesized, for example, a boron nitride container. Then, it is heated for a predetermined time in a nitrogen atmosphere. By doing so, an α-type sialon phosphor can be obtained. It is preferable that the temperature of the heat treatment be 1650°C or higher and 1950°C or lower. By setting the temperature of the heat treatment to 1650°C or higher, the amount of residual unreacted product can be suppressed and primary particles can be sufficiently grown. In addition, by setting the temperature of the heat treatment to 1950°C or lower, significant inter-particle sintering can be suppressed. It is desirable to make the raw material powder bulky when filling it into the container, from the perspective of suppressing inter-particle sintering during heating. Specifically, when filling the raw material powder into the container, the bulk density is 0.6 g / cm³ 3 It is desirable to do it below. The heating time in the heat treatment is preferably 2 hours or more and 24 hours or less, as this is a time range in which problems such as a large amount of unreacted material, insufficient growth of primary particles, or inter-particle sintering do not occur. By the process described above, an α-type sialon phosphor with an ingot-like appearance is produced. By grinding this ingot-like α-type sialon phosphor using a grinder such as a crusher, mortar and pestle grinder, ball mill, vibratory mill, or jet mill, and by sieving it after the grinding process, a powder-like α-type sialon phosphor with adjusted secondary particle size can be obtained. In addition, the particle size of the secondary particles can be adjusted by performing a process of removing secondary particles that are difficult to settle due to their small particle size by dispersing them in an aqueous solution. · Annealing process In the present embodiment, it is preferable to heat (anneal) the powdered α-type sialon phosphor obtained through heat treatment under a nitrogen atmosphere. In this specification, this heat treatment under a nitrogen atmosphere is referred to as the "annealing process." The heating temperature in the annealing process is preferably 1300 to 1600°C, more preferably 1400 to 1500°C. If the heating temperature is 1600°C or higher, it is undesirable because decomposition of the α-type sialon and volatilization of Eu, which is the luminescence center, may occur. Also, if the heating temperature is 1300°C or lower, it is undesirable because crystallinity may not be sufficiently improved. It is preferable that the heating temperature of the annealing process be lower than the heating temperature of the heating process (sintering) described above. It is preferable that the pressure of the annealing process be atmospheric pressure or near atmospheric pressure, specifically 0.02 to 0.9 MPa (gauge pressure). The time for the annealing process is preferably 5 to 20 hours, and more preferably 10 to 18 hours. · Hydrogen gas annealing process After the annealing process, the product obtained from the annealing process is heat-treated under a hydrogen gas atmosphere. In this specification, this process is referred to as the "hydrogen gas annealing process." In the hydrogen gas annealing process, it is preferable to heat-treat the α-type sialon phosphor after the annealing process in a hydrogen gas atmosphere after cooling it to room temperature. By performing the annealing process and the hydrogen gas annealing process in succession, the fluorescence properties are significantly improved. According to the findings of the inventors, the hydrogen gas annealing process is a treatment for reducing defects in the phosphor. It is believed that through heat treatment in a hydrogen gas atmosphere, hydrogen gas enters the crystal and stabilizes the defects in the crystal. As a result, it is believed that an α-type sialon phosphor with an average linear expansion coefficient α´ of 4.2 ppm / ℃ or higher and 4.6 ppm / ℃ or lower, and good luminescence characteristics, is obtained. The heating temperature in the hydrogen gas annealing process is preferably 1300 to 1600°C, and more preferably 1400 to 1500°C. If the heating temperature is 1300°C or lower, hydrogen gas does not enter the crystal lattice, making it difficult to obtain the desired effect, and if it is 1600°C or higher, there is a possibility that the crystal structure of the α-type sialon phosphor will decompose. In addition, it is preferable to set the heating temperature of the hydrogen gas annealing process to a temperature lower than the heating temperature of the above-mentioned calcination process. In the hydrogen gas annealing process, it is preferable to set the pressure to atmospheric pressure or near atmospheric pressure, specifically 0.02 to 0.9 MPa (gauge pressure). The time for the hydrogen gas annealing process is preferably 3 to 16 hours, and more preferably 5 to 12 hours. It is desirable that the purity of the hydrogen gas used in the hydrogen gas annealing process be 99% or higher. In particular, hydrogen gas with a purity of 99.9% or higher is desirable. However, as long as the α-type sialon phosphor of the present embodiment is obtained, a mixed gas of hydrogen gas and another gas may be used in the hydrogen gas annealing process. Examples of other gases include noble gases such as nitrogen gas or argon gas. It is preferable that hydrogen gas be present in the mixed gas at a concentration of 30 vol% or more, and more preferable that it be present at a concentration of 40 vol% or more. · Acid treatment process In this embodiment, it is preferable to perform acid treatment after carrying out the process described above. By doing so, abnormalities that do not contribute to luminescence or cause a decrease in luminescence characteristics are reduced, and in some cases, the luminescence characteristics may be further enhanced. In the acid treatment process, for example, an α-type sialon phosphor is immersed in an acidic aqueous solution. Examples of acidic aqueous solutions include an acidic aqueous solution containing one acid selected from acids such as hydrofluoric acid, nitric acid, and hydrochloric acid, or a mixed acid aqueous solution obtained by mixing two or more of the above acids. Among these, an aqueous hydrofluoric acid solution containing hydrofluoric acid alone and a mixed acid aqueous solution obtained by mixing hydrofluoric acid and nitric acid are more preferred. The concentration of the acidic aqueous solution is appropriately set according to the strength of the acid used, but for example, it is preferably 0.7% or more and 100% or less, and more preferably 0.7% or more and 40% or less. In addition, the temperature at which the acid treatment is performed is preferably 60°C or more and 90°C or less, and the reaction time (immersion time) is preferably 15 minutes or more and 80 minutes or less. By performing stirring at high speed, sufficient acid treatment of the phosphor surface is facilitated. The term "high speed" here depends on the stirring device used; however, when using a laboratory-level magnetic stirrer, the stirring speed is, for example, 400 rpm or higher, and realistically, between 400 rpm and 500 rpm. From the perspective of the purpose of normal stirring, which is to constantly supply fresh acid to the particle surface, a stirring speed of about 200 rpm is sufficient; however, by performing high-speed stirring of 400 rpm or higher, sufficient treatment of the particle surface is facilitated through physical action in addition to chemical action. <Light Emitting Device> Figure 1 is a schematic cross-sectional view illustrating the structure of a light-emitting device. As shown in FIG. 1, the light-emitting device (100) comprises a light-emitting element (120), a heat sink (130), a case (140), a first lead frame (150), a second lead frame (160), a bonding wire (170), a bonding wire (172), and a composite (40). The light-emitting element (120) is mounted on a predetermined area of ​​the upper surface of the heat sink (130). By mounting the light-emitting element (120) on the heat sink (130), the heat dissipation of the light-emitting element (120) can be increased. Additionally, a substrate for a package may be used instead of the heat sink (130). The light-emitting element (120) is a semiconductor device that emits excitation light. As the light-emitting element (120), for example, an LED chip that emits light with a wavelength of 300 nm or more and 500 nm or less, corresponding to near-ultraviolet to blue light, can be used. One electrode (not shown) disposed on the upper surface side of the light-emitting element (120) is connected to the surface of the first lead frame (150) through a bonding wire (170) such as a gold wire. Also, the other electrode (not shown) formed on the upper surface of the light-emitting element (120) is connected to the surface of the second lead frame (160) through a bonding wire (172) such as a gold wire. In the case (140), a roughly funnel-shaped concave portion is formed, in which the diameter of the hole gradually increases upward from the bottom surface. A light-emitting element (120) is provided on the bottom surface of the concave portion. The wall surface of the concave portion surrounding the light-emitting element (120) serves as a reflector. The composite (40) is filled into the concave portion where the wall is formed by the case (140). The composite (40) is a wavelength conversion member that converts the wavelength of the excitation light emitted from the light-emitting element (120) into a long wavelength. As the composite (40), the composite of the present embodiment is used, and the phosphor (1) of the present embodiment is dispersed in a sealing material (30) such as resin. The light-emitting device (100) emits a mixed color of light from the light-emitting element (120) and light generated from the phosphor (1) that absorbs the light of the light-emitting element (120) and is excited. It is preferable that the light-emitting device (100) emits white light through the mixing of the light from the light-emitting element (120) and the light generated from the phosphor (1). For reference, transparent resins such as silicone resin, epoxy resin, and uretain resin can be used as the sealing material (30) in the composite (40). The composite (40) can be manufactured by, for example, adding the α-type sialon phosphor of the present embodiment to a liquid resin or powdered glass or ceramics, mixing them uniformly, and then curing or sintering them by heat treatment. The light-emitting device (100) of the present embodiment has good light-emitting characteristics by using the α-type sialon phosphor described above as the phosphor (1). For reference, in FIG. 1, a surface-mount type light-emitting device is exemplified, but the light-emitting device is not limited to a surface-mount type and may be a projectile type, COB (chip on board) type, or CSP (chip scale package) type. Although embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than those described above may be adopted. Furthermore, the present invention is not limited to the embodiments described above, and modifications and improvements within the scope of achieving the objectives of the present invention are included in the present invention. Examples Embodiments of the present invention are described in detail based on examples and comparative examples. For the sake of clarity, the present invention is not limited to the examples. <Example 1: Preparation of α-type sialon phosphor> In a glove box, 60.14 mass% of Si3N4 powder (Ube Kosan Co., Ltd., E10 grade), 23.96 mass% of AlN powder (Tokuyama Co., Ltd., E grade), 2.07 mass% of EuN powder (Kojundo Kagaku Genkyusho Co., Ltd.), and 13.83 mass% of Ca3N2 powder (Kojundo Kagaku Genkyusho Co., Ltd.) were dry blended as a raw material powder composition such that m value was 3.75, n value was 0, x value was 1.795, and y value was 0.08, and then passed through a nylon sieve with a mesh size of 250 μm. In this way, a raw material mixed powder was obtained. 120g of this raw material mixture powder was filled into a lidded cylindrical boron nitride container with an internal volume of 0.4 liters (manufactured by Denka Corporation, N-1 grade). A container filled with the raw material mixture powder was heat-treated at 1800°C for 16 hours in an atmospheric pressure nitrogen atmosphere using an electric furnace equipped with a carbon heater. Since the calcium nitride contained in the raw material mixture powder is prone to easy hydrolysis in air, the boron nitride container filled with the raw material mixture powder was removed from the glove box, quickly placed in the electric furnace, and immediately vacuum-evacuated to prevent the reaction of calcium nitride. The synthetic compound was lightly crushed using a mortar and pestle and passed through a sieve with a mesh size of 150 μm to obtain a phosphor powder. As a result of investigating the crystal phase of this phosphor powder by X-ray diffraction (hereinafter referred to as XRD measurement) using CuKα rays, the crystal phase present was α-type sialon. A boron nitride container filled with the obtained phosphor powder was heat-treated at 1400°C for 16 hours in an atmospheric pressure nitrogen atmosphere using an electric furnace equipped with a carbon heater (annealing process). The composite was lightly crushed in a mortar and pestle and sieved through a mesh size of 150 μm to obtain phosphor powder. Afterwards, a boron nitride container filled with the above phosphor powder was heat-treated at 1400°C for 16 hours in an atmospheric pressure hydrogen atmosphere using an electric furnace equipped with a metal heater (hydrogen annealing process). The composite was lightly crushed in a mortar and pestle and sieved through a mesh size of 150 μm to obtain phosphor powder. Next, 50 ml of 50% hydrofluoric acid and 50 ml of 70% nitric acid were mixed to prepare a stock solution. 300 ml of distilled water was added to the stock solution, and the concentration of the stock solution was diluted to 25% to prepare 400 ml of a mixed acid aqueous solution. 30 g of powder consisting of the aforementioned α-type sialon phosphor particles was added to this mixed acid aqueous solution. Acid treatment was performed by immersing the powder for 60 minutes while maintaining the temperature of the mixed acid aqueous solution at 80°C and stirring with a magnetic stirrer at a rotation speed of 450 rpm. After acid treatment, the powder was thoroughly washed to remove the acid with distilled water, filtered, dried, and then passed through a sieve with a mesh size of 45 μm. A powdered α-type sialon phosphor was obtained by the above. Compositional analysis was performed on the obtained α-type sialon phosphor to determine x, y, x+y, m, and n in the general formula. The specific method of compositional analysis is as follows. The content of Eu, Ca, Si, and Al in the phosphor was quantitatively analyzed using an ICP emission spectroscopic analyzer (SPECTRO Inc., CIROS-120) after dissolving the α-type sialon phosphor by the pressurized acid digestion method. In addition, the O and N content in the phosphor was quantitatively analyzed using an oxygen nitrogen analyzer (EMGA-920 manufactured by Horiba Seisakusho Co., Ltd.). Based on the compositional analysis results, the general formula of α-type sialon (Ca x , Eu y )(Si 12-(m+n) Al m+n )(O n N 16-n As a result of converting to ), m value: 3.5, n value: 0.27, x value: 1.63, y value: 0.05, x+y value: 1.68. Calculation of Lattice Constant and Average Linear Expansion Coefficient (X-ray diffraction measurement) An α-type sialon phosphor was placed on a sample plate, and the sample was pressed with a glass plate to spread it out so that the surface of the sample and the surface of the sample plate were aligned. Then, X-ray diffraction measurements were performed under the following conditions. Measurements of Si (NIST SRM 640c, hereinafter also referred to as "Si_640c") were also performed as an angle standard sample (external standard). Device: Rigaku X-ray Diffraction Device Ultima IV Optical parallel beam method X-ray source Cu encapsulation tube Applied voltage / current 40kV / 40mA Detector scintillation counter Measurement stage sample high temperature device Measurement atmosphere N2 flow (30 mL / min) Set temperatures 25℃, 300℃, 500℃, 700℃, 900℃ (excluding Si_640c) 25℃(Si_640c) Heating rate 20℃ / min 10-minute interval Measurement angle range 2θ = 24~140° Sampling width 0.04° Scan speed 2° / min 4 repeated measurements (excluding Si_640c) 3 times (Si_640c) Slit configuration Incident-side solar slit: 5.0°, Receiving-side solar slit: 5.0° Thin film PSA DS: 1mm, DS Vertical: 10mm, SS: Open, RS: Open Sample plate Pt (Calculation of lattice constants) In the above X-ray diffraction measurements, the measurement results at each temperature (25℃, 300℃, 500℃, 700℃, 900℃) were used to perform analysis using Jade 9, a comprehensive analysis software for powder X-ray diffraction patterns manufactured by Materials Data. By doing so, precise lattice constants were calculated. The conditions for the analysis are described below. Pawley method Analysis temperatures 25℃, 300℃, 500℃, 700℃, 900℃ Angle range 2θ=24~140°(Note 1) Background 4th-Order Polynomial Refinement Peak shift zero point correction 2θ 0.005948(Note 2) Sample displacement cosθ 0 (fixed) Vertical divergence cot(2θ) -0.012557(Note 2) Peak shape pseudo-Voigt function Peak intensity ratio refinement (Note 1: In the analysis using the Pawley method for the angular range 2θ = 24–140°, if diffraction lines other than α-type sialons appeared, these lines were appropriately excluded for the analysis.) (Note 2: The measurement results of the standard sample (Si_640c) were interpreted, and the obtained values ​​were used.) (Calculation of volumetric expansion rate) (1) For the measured temperature T, the lattice constant a T and c TA graph plotting [it] was constructed. Then, an approximate linear equation was derived for the range of 25–900°C. The approximate linear equation can be obtained by the least squares method. For reference, regarding the crystal structure of α-type sialon, a T wa b T becomes the same value. (2) Using the approximate linear equation, the lattice constant a at 25℃ 25 and c 25 It produced. (3) Using the approximate linear equation, the lattice constant a at 900°C 900 and c 900 It produced. (4) Lattice constant a 25 and c 25 Using the value of, the lattice volume V at 25℃ 25 It produced (Note 3). (5) Lattice constant a 900 and c 900 Using the value of, the lattice volume V at 900℃ 900 It produced (Note 3). (6) The volume expansion rate β was calculated using the following formula. Here, ΔT is 900℃-25℃=875℃. (Note 3: The crystal structure of α-type sialon is hexagonal.) [Mathematical Formula 7] (Calculation of average linear expansion rate) The average linear expansion coefficient α´ was calculated using the equation α´=β / 3. For reference, this equation α´=β / 3 is used to calculate the average linear expansion coefficient as a polycrystalline material, assuming that the sample is an isotropic material. (Calculation of average linear expansion coefficient α1´ at 25~300℃ and average linear expansion coefficient α2´ at 700~900℃) By following the series of steps described above, the average linear expansion coefficient α1´ at 25~300℃ and the average linear expansion coefficient α2´ at 700~900℃ were calculated. (Measurement of particle size distribution and calculation of median diameter) Measurements were taken using the Microtrac MT3300EX II (Microtrac Bell Co., Ltd.) by the laser diffraction scattering method in accordance with JIS R1629:1997. Specifically, first, 0.5 g of powdered α-type sialon phosphor was added to 100 cc of ion-exchanged water, and dispersion treatment was performed for 3 minutes using an Ultrasonic Homogenizer US-150E (Nippon Seiki Seisakusho Co., Ltd., chip size φ20 mm, amplitude 100%, oscillation frequency 19.5 KHz, amplitude approx. 31 μm) to obtain a dispersion. This dispersion was set up in an MT3300EX II, and the particle size distribution was measured. From the obtained particle size distribution, the median diameter D50 was determined. <Evaluation of Luminescence Characteristics> Regarding the obtained powdered α-type sialon phosphor, the absorption rate, internal quantum efficiency, and external quantum efficiency were measured using a spectrophotometer (MCPD-7000 manufactured by Otsuka Denshi Co., Ltd.) and calculated in the following order. Powdered α-type sialon phosphor was packed into a concave cell so that its surface was smooth. This cell was mounted at a predetermined position on an integrating sphere. Monochromatic light spectrally separated to a wavelength of 455 nm from a light-emitting source (Xe lamp) was introduced into this integrating sphere using an optical fiber. This monochromatic light was irradiated onto a sample of phosphor, and the fluorescence spectrum of the sample was measured. A standard reflector (Labsphere Spectraron) with a reflectance of 99% was mounted on the sample, and the spectrum of the excitation light at a wavelength of 455 nm was measured. At that time, the number of excitation light photons (Qex) was calculated from the spectrum in the wavelength range of 450 nm to 465 nm. A cell filled with powdered α-type sialon phosphor was mounted in the sample section, and the number of excitation reflected photons (Qref) and fluorescence photons (Qem) were calculated from the obtained spectrum data. The number of excitation reflected photons was calculated in the same wavelength range as the number of excitation photons, and the number of fluorescence photons was calculated in the range from 465 nm to 800 nm. Absorption rate (%) = (Qex - Qref) / Qex × 100 Internal quantum efficiency (%) = (Qem / (Qex - Qref)) × 100 External quantum efficiency (%) = (Qem / Qex) × 100 Using the above measurement method, when the standard sample NSG1301 sold by Sialon Co., Ltd. was measured, the external quantum efficiency was 55.6% and the internal quantum efficiency was 74.8%. The device was calibrated using this sample as a standard. <Example 2: Preparation and Evaluation of α-Type Sialon Phosphor> Except for changing the composition of the introduction, an α-type sialon phosphor was prepared using the same method as in Example 1. Then, the luminescence characteristics were evaluated. In the manufactured α-type sialon phosphor, the m value was 3.0, the n value was 0.25, the x value was 1.45, the y value was 0.05, and the x+y value was 1.50. <Example 3: Preparation and Evaluation of α-Type Sialon Phosphor> Except for changing the composition of the introduction, an α-type sialon phosphor was prepared using the same method as in Example 1. Then, the luminescence characteristics were evaluated. In the manufactured α-type sialon phosphor, the m value was 4.0, the n value was 0.21, the x value was 1.94, the y value was 0.06, and the x+y value was 2.01. <Comparative Example 1: Preparation and Evaluation of α-Type Sialon Phosphor> An α-type sialon phosphor was prepared using the same method as in Example 1, except that the composition was changed and the hydrogen annealing process was not performed. Then, the luminescence characteristics were evaluated. In the manufactured α-type sialon phosphor, the m value was 2.0, the n value was 0.32, the x value was 0.94, the y value was 0.06, and the x+y value was 1.00. <Comparative Example 2: Preparation and Evaluation of α-Type Sialon Phosphor> An α-type sialon phosphor was prepared using the same method as in Example 1, except that the composition was changed and the hydrogen annealing process was not performed. Then, the luminescence characteristics were evaluated. In the manufactured α-type sialon phosphor, the m value was 3.5, the n value was 1.47, the x value was 1.70, the y value was 0.05, and the x+y value was 1.75. Information regarding each example and comparative example is summarized in the table below. In the table, the units of each value are as follows. α´, α1´ and α2´: ppm / ℃ a 25 and c 25 : Å V 25 : Å 3 Absorption rate, internal quantum efficiency and external quantum efficiency: % [Table 1]

[0093] [Table 2]

[0094] As shown in Tables 1 and 2, general formula: (Ca x , Eu y )(Si 12-(m+n) Al m+n )(O n N 16-n In ), 0 <x<2.0, 0<y≤0.5, 0.3≤x+y≤2.2, 0<m≤4.0 및 0<n≤3.0을 충족시키는 조성을 갖고, 또한, 25~900℃에서의 평균 선팽창률 α´가 4.2ppm ℃ 이상 4.6ppm 이하인 α형 사이알론 형광체는, 그렇지 않은 형광체에 대하여, 양호한 내부 양자 효율 외부 효율을 나타냈다.This application claims priority based on Japanese Patent Application No. 2023-059122 filed on March 31, 2023, and incorporates all of the disclosures thereof herein. Explanation of the symbols 1 Phosphor 30 bag materials 40 complex 100 light-emitting devices 120 light-emitting elements 130 heat sink 140 cases 150 1st Lead Frame 160 2nd Lead Frame 170 bonding wire 172 Bonding Wire

Claims

Claim 1 An α-type sialon phosphor represented by the general formula below, having an average linear expansion coefficient α´ from 25 to 900°C of 4.2 ppm / °C or higher and 4.6 ppm / °C or lower. General formula: (Ca x , Eu y )(Si 12-(m+n) Al m+n )(O n N 16-n In the above general formula, x, y, m, and n satisfy the following: 1.3≤x<2.0 0.01≤y≤0.06 1.3≤x+y≤2.0 2.8≤m<4.0 0.1≤n≤0.27 Claim 2 An α-type sialon phosphor as described in claim 1, wherein α2´ / α1´ is 1.3 to 1.8 when the average linear expansion coefficient at 25 to 300°C is α1´ and the average linear expansion coefficient at 700 to 900°C is α2´. Claim 3 As an α-type sialon phosphor described in claim 1 or claim 2, at 25°C, the lattice constant of the unit cell a 25 α is between 7.900 Å and 7.960 Å, and the lattice constant c 25 α-type sialon phosphor with a diameter of 5.720 Å or more and 5.780 Å or less. Claim 4 As an α-type sialon phosphor described in claim 1 or claim 2, at 25°C, the lattice volume V of the unit cell 25 308Å 3 Above 320Å 3 α-type sialon phosphor with less than 100 parts. Claim 5 A light-emitting device comprising a light-emitting element and an α-type sialon phosphor described in claim 1 or claim 2, and a wavelength conversion unit that converts light emitted from the light-emitting element into a long wavelength. Claim 6 delete Claim 7 delete

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