Phosphor powder, composite, and light emitting device

Abstract

One aspect of the present application is a phosphor powder composed of Eu-containing α-Sialon phosphor particles. The volume-based median particle diameter (D 50 ) of the phosphor powder, measured using a laser diffraction scattering method, is 10 μm to 20 μm, and the diffuse reflectance for light having a wavelength of 600 nm is 93% to 99%.

Description

[0001] This application is a divisional application of Chinese patent application No. 202080025140.8 (the original application was entitled "Fluorescent Powder, Composite and Light-Emitting Device", and the original application was filed on March 24, 2020). Technical Field

[0002] This invention relates to phosphor powders, composites, and light-emitting devices. Background Technology

[0003] As nitride and oxide phosphors, α-type silron phosphors obtained by activating specific rare earth elements are known to possess useful fluorescence properties and are applied in white LEDs, etc. In α-type silron phosphors, the Si-N bonds of the α-type silicon nitride crystal are partially replaced by Al-N and Al-O bonds. To maintain electroneutrality, specific elements (Ca, Li, Mg, and Y, or lanthanide metals excluding La and Ce) are incorporated into the lattice structure. By setting a portion of the incorporated elements as rare earth elements that become luminescent centers, fluorescence properties are exhibited. Among them, α-type silron phosphors obtained by dissolving Ca and replacing a portion of it with Eu are relatively effectively excited in a broad wavelength region from the ultraviolet to the cyan region, exhibiting yellow to orange luminescence. As an attempt to further improve the fluorescence properties of such α-type silron phosphors, for example, it has been proposed to select α-type silron phosphors with specific average particle sizes through a hierarchical process (Patent Document 1).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2009-96882 Summary of the Invention

[0007] In recent years, there has been a need for further increases in the brightness of white LEDs. For example, there is also a demand for further improvements in the luminescent properties of the phosphor powder used in white LEDs.

[0008] The present invention addresses the problems described above. The object of the present invention is to provide a phosphor powder with improved luminescent properties.

[0009] According to the present invention, a phosphor powder is provided, comprising α-type thionyl phosphor particles containing Eu, wherein the median particle size (D) on a volume basis is determined by laser diffraction scattering. 50 The micrometer diameter is 10μm to 20μm, and the diffusion reflectance of light with a wavelength of 600nm is 93% to 99%.

[0010] In addition, according to the present invention, a composite is provided comprising the above-described phosphor powder and a sealing material for sealing the phosphor powder.

[0011] In addition, according to the present invention, a light-emitting device is provided, comprising a light-emitting element that emits excitation light and the aforementioned composite that converts the wavelength of the excitation light.

[0012] According to the present invention, techniques related to phosphor powders with improved luminescent properties can be provided. Attached Figure Description

[0013] Figure 1 This represents the median particle size (D) of conventional phosphor powders. 50 The relationship between the reflectivity and the diffusion reflectance of light at a wavelength of 600 nm, and the median particle size (D) specified for the phosphor powder of this embodiment. 50 (and a conceptual diagram of the range of diffuse reflectivity for light with a wavelength of 600 nm.)

[0014] Figure 2 This is a schematic cross-sectional view showing the structure of the light-emitting device according to the embodiment. Detailed Implementation

[0015] The embodiments of the present invention will be described in detail below.

[0016] The phosphor powder of this embodiment is a phosphor powder composed of α-type thionon phosphor particles containing Eu. The median particle size (D) of this phosphor powder, measured using laser diffraction scattering as a volume reference, is... 50 The micrometer diameter is 10μm to 20μm, and the diffusion reflectance of light with a wavelength of 600nm is 93% to 99%.

[0017] The phosphor powder according to this embodiment can maintain the excitation wavelength region and fluorescence wavelength region of conventional α-type thionyl phosphor particles and improve their fluorescence characteristics. Therefore, the luminescence characteristics of the light-emitting device obtained using the phosphor powder of this embodiment can be improved.

[0018] The detailed mechanism for this reason is not yet clear, but it is believed that by taking into account both setting the median particle size in the range of 10 μm to 20 μm and setting the diffusion reflectance for light with a wavelength of 600 nm in the range of 93% to 99%, the fluorescence properties of the phosphor powder can be improved.

[0019] (α-type thionolite particles)

[0020] The α-type silon phosphor particles containing Eu are composed of the α-type silon phosphors described below.

[0021] α-type thionolites are composed of the general formula: (M1 x M2 y Eu z (Si) 12－（m＋n） Alm＋n (O) n N 16－n (where M1 is a monovalent Li element and M2 is one or more divalent elements selected from Mg, Ca and lanthanides (excluding La and Ce)) represents an α-type thionon phosphor containing Eu.

[0022] The solid solution composition of α-type silon phosphors is represented by x, y, z in the above general formula, and m and n determined by the accompanying Si / Al ratio and O / N ratio, where 0 ≤ x < 2.0, 0 ≤ y < 2.0, 0 < z ≤ 0.5, 0 < x + y, 0.3 ≤ x + y + z ≤ 2.0, 0 < m ≤ 4.0, and 0 < n ≤ 3.0. In particular, if Ca is used as M2, the α-type silon phosphor is stabilized over a wide compositional range. By replacing a portion of it with Eu, which becomes the luminescence center, and exciting it with light in a broad wavelength range from ultraviolet to cyan, phosphors exhibiting visible emission from yellow to orange can be obtained.

[0023] Furthermore, from the viewpoint of obtaining bulb-colored light in lighting applications, α-type silron phosphors preferably do not contain Li as a solid solution component, or if they do, it is in a small amount. If we consider the above general formula, it is preferably 0 ≤ x ≤ 0.1. And / or the ratio of Li in the α-type silron phosphor is preferably 0% by mass to 1% by mass.

[0024] Generally, the solid solution composition of α-type thionon phosphors cannot be strictly defined by compositional analysis due to the presence of a second crystalline phase different from the α-type thionon phosphor and the unavoidable presence of an amorphous phase. The preferred crystalline phase for α-type thionon phosphors is a single α-type thionon phase, but it may also include aluminum nitride or its polymorphs as other crystalline phases.

[0025] For α-type silon phosphor particles, multiple equiaxed primary particles are sintered to form bulk secondary particles. In this embodiment, primary particles refer to the smallest particles that can exist independently and can be observed with an electron microscope or the like. The shape of α-type silon phosphor particles is not particularly limited. Examples of shapes include spheres, cubes, cylinders, and amorphous shapes.

[0026] The median particle size (D) of the phosphor powder in this embodiment 50 The median particle size (D) of the phosphor powder in this embodiment is 10 μm or more, preferably 12 μm or more. 50 The upper limit of the diameter of the phosphor powder is 20 μm or less, more preferably 18 μm or less. The median particle size (D) of the phosphor powder in this embodiment is... 50 ) represents the size of the aforementioned secondary particle.

[0027] Here, the median particle size (D) of the phosphor powder is... 50() refers to the 50% particle size in the cumulative fraction of the volume standard determined by laser diffraction scattering method according to JIS R1629:199.

[0028] The fluorescent particles in this embodiment satisfy the requirement that the median particle size (D) 50 The above-mentioned range and the condition of a diffuse reflectance of 93% to 99% for light with a wavelength of 600 nm are set. The diffuse reflectance can be measured by an ultraviolet-visible spectrophotometer equipped with an integrating sphere. It should be noted that, from the viewpoint of further improving the luminescence characteristics, the diffuse reflectance for light with a wavelength of 600 nm is preferably 94% to 99%, and more preferably 94% to 96%.

[0029] Figure 1 This represents the median particle size (D) of conventional phosphor powders. 50 The relationship between the reflectivity and the diffusion reflectance of light at a wavelength of 600 nm, and the median particle size (D) specified for the phosphor powder of this embodiment. 50 (and a conceptual diagram of the range of diffuse reflectivity for light with a wavelength of 600 nm.)

[0030] Based on the accumulated understanding of α-type silon phosphors, for previous α-type silon phosphor powders, if the diffusion reflectance of light at a wavelength of 600 nm is compared with the median particle size (D... 50 The relationship between ) is plotted on Figure 1 Then located at Figure 1 The curve shown is near this area. In contrast, for the phosphor powder of this embodiment, it was found that by optimizing the manufacturing method described later, a median particle size (D...) can be achieved. 50 The diffusion reflectivity is adjusted to a higher range of 93% to 99% within the range of 10μm to 20μm, which is higher than before, thereby improving the luminescence characteristics.

[0031] Furthermore, for the phosphor powder of this embodiment, by adjusting the median particle size (D... 50 By setting the light emission characteristics to the range specified above and the diffuse reflectance to at least one of the following conditions, the light emission characteristics can be further improved.

[0032] (i) Let the cumulative 10% particle size and the cumulative 90% particle size of the volume reference determined by laser diffraction scattering be D respectively. 10 D 90 At that time, (D) 90 -D 10 ) / D 50 It ranges from 1.0 to 1.5.

[0033] (ii) The diffuse reflectance of light with a wavelength of 500 nm is 66%–80%.

[0034] (iii) The difference (X1 - X2) between the diffuse reflectance X1 (%) for light with a wavelength of 800 nm and the diffuse reflectance X2 (%) for light with a wavelength of 600 nm is less than 3.0 (%).

[0035] Based on the phosphor powder described above, the median particle size (D) of the volume reference determined by laser diffraction scattering method is taken into account. 50 Setting the range to 10μm to 20μm and the range to 93% to 99% for the diffusion reflectance of light with a wavelength of 600nm can improve fluorescence properties.

[0036] (Method for manufacturing phosphor powder)

[0037] The method for manufacturing phosphor powder composed of α-type silon phosphor particles according to this embodiment will be described. For α-type silon phosphor particles, during the synthesis process, mainly a portion of the raw material powder reacts and forms a liquid phase, through which the elements move, thereby forming a solid solution and growing the particles.

[0038] First, raw materials containing elements constituting α-type silon phosphor particles containing Eu are mixed. Specifically, in α-type silon phosphor particles with low oxygen content synthesized using calcium nitride as the calcium raw material, calcium is dissolved in a high concentration. In particular, with a high Ca solid solution concentration, phosphors with emission peak wavelengths at higher wavelengths (above 590 nm, more specifically 590 nm to 610 nm, and even more specifically 592 nm to 608 nm) can be obtained compared to conventional compositions using oxide raw materials. Specifically, in the above general formula, 1.5 < x + y + z ≤ 2.0 is preferred. A portion of Ca can also be substituted with Li, Mg, Sr, Ba, Y, and lanthanides (excluding La and Ce) and the emission spectrum can be fine-tuned.

[0039] Examples of raw material powders other than those mentioned above include silicon nitride, aluminum nitride, and Eu compounds. Eu compounds include europium oxide, compounds that become europium oxide upon heating, and europium nitride. Europium nitride, which can reduce the oxygen content in the system, is preferred.

[0040] If a suitable amount of pre-synthesized α-type silon phosphor particles are added to the raw material powder, this becomes the basis for particle growth, and α-type silon phosphor particles with a larger short axis diameter can be obtained. The particle shape can be controlled by changing the morphology of the added α-type silon particles.

[0041] Methods for mixing the above-mentioned raw materials include dry mixing and wet mixing in an inert solvent that does not substantially react with the components of the raw materials, followed by solvent removal. Mixing apparatus includes V-type mixers, oscillating mixers, ball mills, and vibratory mills. For the mixing of calcium nitride, which is unstable in the atmosphere, since its hydrolysis and oxidation can affect the properties of the synthesized product, it is preferable to carry out the mixing in a glove box with an inactive atmosphere.

[0042] The mixed powder (hereinafter referred to as the raw material powder) is filled into a container made of a material with low reactivity to the raw material and the synthesized phosphor, such as a boron nitride container. Then, it is heated in a nitrogen atmosphere for a specified time. This yields an α-type thionon phosphor. The heat treatment temperature is preferably set to 1650°C to 1950°C.

[0043] By setting the heat treatment temperature above 1650°C, the residual amount of unreacted products can be suppressed, allowing primary particles to grow sufficiently. Furthermore, setting it below 1950°C can significantly suppress interparticle sintering.

[0044] From the viewpoint of suppressing interparticle sintering during heating, it is preferable to increase the volume of the raw material powder when filling the container. Specifically, it is preferable to set the bulk density of the raw material powder to 0.6 g / cm³ when filling the container. 3 the following.

[0045] The preferred heating time for heat treatment is 2 to 24 hours, which is a time range that prevents unreacted substances from existing in large quantities, insufficient particle growth in one stage, or sintering between particles.

[0046] Through the above processes, an ingot-shaped α-type silon phosphor is generated. This ingot-shaped α-type silon phosphor is then subjected to a pulverization process using various pulverizers, including a grinder, mortar and pestle, ball mill, vibratory mill, and jet mill, followed by a sieving and classification process. This process yields a D-type phosphor with adjusted secondary particles. 50 Phosphor powder composed of α-type thionolite particles obtained by adjusting particle size. Furthermore, by performing a process of dispersing the phosphor powder in an aqueous solution to remove secondary particles with small particle size and poor sedimentation, the D-value of the secondary particles can be adjusted. 50 Particle size.

[0047] The phosphor powder composed of α-type thionolite particles in the embodiment can be produced by performing an acid treatment process after performing the above-described steps.

[0048] In the acid treatment process, α-type thionyl phosphor particles are impregnated in an acidic aqueous solution, for example. Examples of acidic aqueous solutions include those containing one acid selected from hydrofluoric acid, nitric acid, hydrochloric acid, etc., or mixed acid aqueous solutions obtained by mixing two or more of the aforementioned acids. More preferably, these are hydrofluoric acid aqueous solutions containing only hydrofluoric acid and mixed acid aqueous solutions obtained by mixing hydrofluoric acid and nitric acid. The concentration of the original acidic aqueous solution is appropriately set according to the strength of the acid used, for example, preferably 0.7% to 100%, more preferably 0.7% to 40%. Furthermore, the temperature during acid treatment is preferably 25°C to 90°C, more preferably 60°C to 90°C, and the reaction time (impregnation time) is preferably 15 minutes to 80 minutes.

[0049] In the acid treatment process, high-speed stirring of the acidic aqueous solution is preferred. High-speed stirring facilitates thorough acid treatment. The term "high speed" depends on the stirring device used, but when using a laboratory-grade magnetic stirrer, the stirring speed is, for example, 400 rpm or higher, and practically 400 rpm to 500 rpm.

[0050] From the viewpoint of continuously supplying fresh acid to the particle surface, a stirring speed of around 200 rpm is considered sufficient. However, according to the inventors' understanding, in this embodiment, by performing high-speed stirring at 400 rpm or higher, it is possible to treat the particle surface through physical means in addition to chemical action. Furthermore, it is believed that phosphor powder with a diffusion reflectance of 93% to 99% for light with a wavelength of 600 nm can be easily obtained.

[0051] Median particle size (D) of phosphor powder 50 The diffuse reflectance of the phosphor powder to light with a wavelength of 600 nm can be optimally controlled by adjusting the degree of pulverization in the pulverization process, the mesh size of the sieve used in the sieving process, the concentration of the original acidic aqueous solution used in the acid treatment, the temperature during acid treatment, and the reaction time. For example, referring to the numerous embodiments described later, acid treatment can be performed using conditions similar to the combination of pulverization, sieving, original acidic aqueous solution concentration, temperature during acid treatment, and reaction time, thereby reducing the median particle size (D) of the phosphor powder. 50 The desired values ​​are obtained for the diffusion reflectivity of light with a wavelength of 600 nm.

[0052] (complex)

[0053] The composite of this embodiment includes the aforementioned phosphor particles and a sealing material for sealing the phosphor particles. In the composite of this embodiment, a plurality of the aforementioned phosphor particles are dispersed in the sealing material. Known materials such as resins, glass, and ceramics can be used as the sealing material. Examples of resins used as the sealing material include transparent resins such as silicone resins, epoxy resins, and polyurethane resins.

[0054] As a method for manufacturing the composite, one can exemplify the following: adding the powder composed of α-type silon phosphor particles of this embodiment to a liquid resin or powdered glass or ceramic, mixing them uniformly, and then curing or sintering them by heat treatment.

[0055] (Light-emitting device)

[0056] Figure 2 This is a schematic cross-sectional view showing the structure of the light-emitting device according to the embodiment. For example... Figure 2 As shown, the light-emitting device 100 includes a light-emitting element 120, a heat sink 130, a housing 140, a first lead frame 150, a second lead frame 160, a bonding wire 170, a bonding wire 172, and a composite 40.

[0057] The light-emitting element 120 is mounted on a designated area 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 improved. It should be noted that a packaging substrate can also be used instead of the heat sink 130.

[0058] The light-emitting element 120 is a semiconductor element that emits excitation light. For example, an LED chip can be used as the light-emitting element 120, which generates light with wavelengths from 300 nm to 500 nm, corresponding to near-ultraviolet to cyan light. An electrode (not shown) disposed on the upper surface of the light-emitting element 120 is connected to the surface of the first lead frame 150 via bonding wires such as gold wires 170. Furthermore, another 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 via bonding wires such as gold wires 172.

[0059] In the housing 140, a generally funnel-shaped recess is formed, with the aperture gradually increasing from the bottom to the top. The light-emitting element 120 is disposed on the bottom surface of the recess. The wall surface of the recess surrounding the light-emitting element 120 acts as a reflector.

[0060] The composite 40 fills the aforementioned recess in which the shell 140 forms a wall. The composite 40 is a wavelength conversion member that converts the excitation light emitted from the light-emitting element 120 into light of a longer wavelength. As the composite 40, the composite of this embodiment disperses the α-type silon phosphor particles 1 of this embodiment 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 by the α-type silon phosphor particles 1 that absorb and are excited by the light from the light-emitting element 120. Preferably, the light-emitting device 100 emits white light through the mixing of the light from the light-emitting element 120 and the light generated by the α-type silon phosphor particles 1.

[0061] In the light-emitting device 100 of this embodiment, as described above, the phosphor powder composed of α-type thionyl phosphor particles 1 satisfies the median particle size (D) of the volume reference determined by laser diffraction scattering. 50 The conditions of 10μm to 20μm and the diffusion reflectance of light with a wavelength of 600nm of 93% to 99% can improve the fluorescence characteristics of α-type silon phosphor particles 1 and complex 40, thereby increasing the luminescence intensity of the light-emitting device 100.

[0062] exist Figure 2 The image shows a surface-mount type light-emitting device, but the light-emitting device is not limited to surface-mount type. The light-emitting device can also be bullet type, COB (Chip-on-Board) type, or CSP (Chip-Scale Package) type.

[0063] The embodiments of the present invention have been described above, but these are merely examples of the present invention, and various configurations other than those described above may also be employed.

[0064] Example

[0065] The present invention will now be described by way of examples and comparative examples, but the present invention is not limited thereto.

[0066] (Example 1)

[0067] As the composition of the raw material powder, silicon nitride powder (manufactured by Ube Industries, Ltd., E10 grade) was set at 62.4 parts by weight, aluminum nitride powder (manufactured by Tokuyama Corporation, E grade) was set at 22.5 parts by weight, europium oxide powder (manufactured by Shin-Etsu Chemical Industry Co., Ltd., RU grade) was set at 2.2 parts by weight, and calcium nitride powder (manufactured by High Purity Chemical Research Institute Co., Ltd.) was set at 12.9 parts by weight. The raw material powders were dry-mixed in a glove box and then passed through a nylon sieve with a mesh size of 250 μm to obtain a raw material mixed powder. 120 g of the raw material mixed powder was filled into a covered cylindrical boron nitride container (manufactured by Denka Co., Ltd., N-1 grade) with an internal volume of 0.4 liters.

[0068] The raw material mixture powder, along with its container, was heated in an electric furnace with a carbon heater at atmospheric pressure and a nitrogen atmosphere for 16 hours at 1800°C. Since the calcium nitride contained in the raw material mixture powder is easily hydrolyzed in air, the boron nitride container filled with the raw material mixture powder was quickly placed in the electric furnace after being removed from the glove box, and immediately subjected to vacuum degassing to prevent the calcium nitride from reacting.

[0069] The synthesized material was gently crushed in a mortar and pestle until it passed through a 150 μm sieve to obtain phosphor powder. The crystal phase of the phosphor powder was investigated by powder X-ray diffraction using CuKα rays. The results showed that the existing crystal phase was a Ca-α thionolite containing Eu (an α-type thionolite containing Ca).

[0070] Next, 3.2 ml of 50% hydrofluoric acid and 0.8 ml of 70% nitric acid were mixed to prepare a stock solution. 396 ml of distilled water was added to the stock solution to dilute its concentration to 1.0%, preparing 400 ml of a mixed acid aqueous solution. 30 g of the phosphor powder composed of α-type silon phosphor particles was added to this mixed acid aqueous solution. The temperature of the mixed acid aqueous solution was maintained at 80°C, and the solution was stirred using a magnetic stirrer at a rotation speed of 450 rpm while simultaneously undergoing an acid treatment for 30 minutes. The acid-treated powder was thoroughly rinsed with distilled water, filtered, dried, and then passed through a 45 μm mesh sieve to prepare the phosphor powder composed of α-type silon phosphor particles of Example 1.

[0071] (Example 2)

[0072] Instead of the mixed acid aqueous solution used in Example 1, 396 ml of distilled water was added to the mixed stock solution obtained by mixing 1.2 ml of 50% hydrofluoric acid and 2.8 ml of 70% nitric acid to prepare a mixed acid aqueous solution with a stock solution concentration of 1.0%. Otherwise, the phosphor powder composed of α-type thionolite particles of Example 2 was prepared using the same steps as in Example 1.

[0073] (Example 3)

[0074] Instead of the mixed acid aqueous solution used in Example 1, 380 ml of distilled water was added to the mixed stock solution obtained by mixing 10 ml of 50% hydrofluoric acid and 10 ml of 70% nitric acid to prepare a mixed acid aqueous solution with a stock solution concentration of 5.0%. The phosphor powder was immersed in the mixed acid aqueous solution for 30 minutes while maintaining the temperature of the mixed acid aqueous solution at 30°C. Otherwise, the phosphor powder composed of α-type thionyl phosphor particles of Example 3 was prepared using the same steps as in Example 1.

[0075] (Example 4)

[0076] Instead of the mixed acid aqueous solution used in Example 1, 300 ml of distilled water was added to the mixed stock solution obtained by mixing 50 ml of 50% hydrofluoric acid and 50 ml of 70% nitric acid to prepare a mixed acid aqueous solution with a stock solution concentration of 25%. The phosphor powder was immersed in the mixed acid aqueous solution for 60 minutes while maintaining the temperature of the mixed acid aqueous solution at 80°C. Otherwise, the phosphor powder composed of α-type thionyl phosphor particles of Example 4 was prepared using the same steps as in Example 1.

[0077] (Comparative Example 1)

[0078] Instead of the mixed acid aqueous solution used in Example 1, a mixed acid aqueous solution with a stock solution concentration of 0.5% was prepared by adding 398 ml of distilled water to a mixed stock solution obtained by mixing 1.0 ml of 50% hydrofluoric acid and 1.0 ml of 70% nitric acid. The temperature of the mixed acid aqueous solution was maintained at 80°C, and the mixture was stirred at a rotation speed of 300 rpm using a magnetic stirrer while being immersed in acid for 30 minutes. Otherwise, the phosphor powder composed of α-type thionyl phosphor particles of Comparative Example 1 was prepared using the same steps as in Example 1.

[0079] In the method for producing phosphor powder composed of α-type thionolite particles in Comparative Example 1, the concentration of the stock solution of the mixed acid aqueous solution used for acid treatment was set to the level of the conventional implementation.

[0080] (Comparative Example 2)

[0081] The mixture obtained in Example 1 was gently crushed in a mortar and then pulverized using a ball mill with Φ1mm zirconia balls. Instead of the mixed acid aqueous solution used, a mixed acid aqueous solution with a stock solution concentration of 25% was prepared by adding 300ml of distilled water to a mixed stock solution obtained by mixing 50ml of 50% hydrofluoric acid and 50ml of 70% nitric acid. The phosphor powder was immersed in the mixed acid aqueous solution for 60 minutes while maintaining the temperature at 80°C. Otherwise, the phosphor powder composed of α-type thionyl phosphor particles of Comparative Example 2 was prepared using the same steps as in Example 1.

[0082] (Particle size determination)

[0083] Particle size was determined using a Microtrac MT3300EX II (manufactured by Microtrac Bel Co., Ltd.) via laser diffraction scattering according to JISR 1629:1997. 0.5 g of phosphor powder was added to 100 cc of ion-exchanged water and dispersed for 3 minutes using an Ultrasonic Homogenizer US-150E (Nippon Seiki Co., Ltd., chip size Φ20 mm, amplitude 100%, oscillation frequency 19.5 kHz, amplitude approximately 31 μm). Particle size was then measured using the MT3300EX II. The median particle size (D0) was determined from the obtained particle size distribution. 50 In addition, the cumulative 10% particle size on a volumetric basis (D) was calculated separately. 10 ), volumetric cumulative 90% particle size (D) 90 ), calculate (D) 90 -D 10 ) / D 50 The results obtained for particle size are shown in Table 1.

[0084] (Diffuse reflectivity)

[0085] Diffusion reflectance was measured using an integrating sphere (ISV-722) mounted on a UV-Vis spectrophotometer (V-650) manufactured by Nippon Spectrophotometer Co., Ltd. Baseline correction was performed using a standard reflector (Spectralon), and a solid sample holder filled with phosphor powder was mounted. Diffusion reflectance at wavelengths of 500 nm, 600 nm, 700 nm, and 800 nm was measured. The results for diffusion reflectance are shown in Table 1.

[0086] (Luminous properties)

[0087] For each phosphor powder obtained, the internal quantum efficiency and external quantum efficiency were measured by a spectrophotometer (MCPD-7000 manufactured by Otsuka Electronics Co., Ltd.) and calculated using the following steps.

[0088] Phosphor powder is filled into a concave cuvette with a smooth surface, and an integrating sphere is installed. Monochromatic light of 455 nm wavelength, split from a light source (Xe lamp), is guided into the integrating sphere using an optical fiber. The phosphor powder sample is then irradiated with this monochromatic light as the excitation source, and the fluorescence spectrum of the sample is measured.

[0089] A standard reflector (Spectralon, Labsphere) with a reflectivity of 99% was installed on the sample section, and the spectrum of the excitation light at a wavelength of 455 nm was measured. At this time, the number of excitation photons (Qex) was calculated from the spectrum in the wavelength range of 450 nm to 465 nm.

[0090] Phosphor powder composed of α-type thionolite particles was mounted on the sample section. The peak wavelength was determined from the obtained spectral data, and the number of excitation-reflected photons (Qref) and the number of fluorescence photons (Qem) were calculated. The number of excitation-reflected photons was calculated within the same wavelength range as the number of excitation photons, and the number of fluorescence photons was calculated within the range of 465 nm to 800 nm.

[0091] Internal quantum efficiency = (Qem / (Qex - Qref)) × 100

[0092] External quantum efficiency = (Qem / Qex) × 100

[0093] When measuring the standard sample NSG 1301 sold by Sialon Co., Ltd. using the above-described measurement method, the external quantum efficiency was 55.6% and the internal quantum efficiency was 74.8%. This sample was used as a standard to calibrate the device. The results obtained for the internal and external quantum efficiencies are shown in Table 1.

[0094] [Table 1]

[0095]

[0096] As shown in Table 1, the median particle size (D) was confirmed to be met. 50 The phosphor powders of Examples 1-4, which have a particle size of 10μm to 20μm and a diffusion reflectance of 93% to 99% for light with a wavelength of 600nm, show improved internal and external quantum efficiencies compared to Comparative Examples 1 and 2, which do not meet these conditions.

[0097] (Additional Examples)

[0098] The additional examples (Experimental Example 1 and Experimental Example 2 below) demonstrate that D 50 Phosphor powders with a diameter of 10μm to 20μm and a diffusion reflectance of 93% to 99% for light with a wavelength of 600nm exhibit good fluorescence properties.

[0099] Experimental Example 1 is an example of enhanced acid treatment compared to Examples 1-4, and Experimental Example 2 is an example of slightly changing the raw material composition compared to Examples 1-4.

[0100] Experimental Example 1

[0101] As the composition of the raw material powder, silicon nitride powder (manufactured by Ube Industries, Ltd., E10 grade) was set at 62.4 parts by weight, aluminum nitride powder (manufactured by Tokuyama Corporation, E grade) was set at 22.5 parts by weight, europium oxide powder (manufactured by Shin-Etsu Chemical Industry Co., Ltd., RU grade) was set at 2.2 parts by weight, and calcium nitride powder (manufactured by High Purity Chemical Research Institute Co., Ltd.) was set at 12.9 parts by weight. The raw material powders were dry-mixed in a glove box and then passed through a nylon sieve with a mesh size of 250 μm to obtain a raw material mixed powder. 120 g of the raw material mixed powder was filled into a covered cylindrical boron nitride container (manufactured by Denka Co., Ltd., N-1 grade) with an internal volume of 0.4 liters.

[0102] The raw material mixture powder, along with its container, was heated in an electric furnace with a carbon heater at atmospheric pressure and nitrogen atmosphere for 16 hours at 1800°C. Since the calcium nitride contained in the raw material mixture powder is easily hydrolyzed in air, the boron nitride container filled with the raw material mixture powder was quickly placed in the electric furnace after being removed from the glove box, and immediately subjected to vacuum degassing to prevent the calcium nitride from reacting.

[0103] The synthesized material was gently crushed in a mortar and pestle, allowing it to pass entirely through a 150 μm mesh sieve to obtain phosphor powder. The crystal phase of this phosphor powder was investigated using powder X-ray diffraction with CuKα rays, and the results showed that the existing crystal phase was a Ca-α type serone containing Eu (an α-type serone containing Ca).

[0104] Then, 100 ml of 50% hydrofluoric acid and 100 ml of 70% nitric acid were mixed to prepare a stock solution. 200 ml of distilled water was added to the stock solution to dilute its concentration to 50.0%, preparing 400 ml of a mixed acid aqueous solution. 30 g of the phosphor powder composed of α-type silon phosphor particles was added to this mixed acid aqueous solution. The temperature of the mixed acid aqueous solution was maintained at 80°C, and the solution was stirred using a magnetic stirrer at a rotation speed of 450 rpm while simultaneously undergoing an acid treatment for 30 minutes. The acid-treated powder was thoroughly rinsed with distilled water, filtered, dried, and then passed through a 45 μm mesh sieve to prepare the phosphor powder composed of α-type silon phosphor particles of Example 1.

[0105] Experiment Example 2

[0106] As the composition of the raw material powder, silicon nitride powder (manufactured by Ube Industries, Ltd., E10 grade) was set at 62.8 parts by weight, aluminum nitride powder (manufactured by Tokuyama Corporation, E grade) was set at 22.7 parts by weight, europium oxide powder (manufactured by Shin-Etsu Chemical Industry Co., Ltd., RU grade) was set at 1.1 parts by weight, and calcium nitride powder (manufactured by High Purity Chemical Research Institute Co., Ltd.) was set at 13.4 parts by weight. The raw material powders were dry-mixed in a glove box and then passed through a nylon sieve with a mesh size of 250 μm to obtain a raw material mixed powder. 120 g of the raw material mixed powder was filled into a covered cylindrical boron nitride container (manufactured by Denka Co., Ltd., N-1 grade) with an internal volume of 0.4 liters.

[0107] The raw material mixture powder, along with its container, was heated in an electric furnace with a carbon heater at atmospheric pressure and nitrogen atmosphere for 16 hours at 1800°C. Since the calcium nitride contained in the raw material mixture powder is easily hydrolyzed in air, the boron nitride container filled with the raw material mixture powder was quickly placed in the electric furnace after being removed from the glove box, and immediately subjected to vacuum degassing to prevent the calcium nitride from reacting.

[0108] The synthesized material was gently crushed in a mortar and pestle until it passed through a 150 μm sieve to obtain phosphor powder. The crystal phase of the phosphor powder was investigated by powder X-ray diffraction using CuKα rays. The results showed that the existing crystal phase was a Ca-α thionolite containing Eu (an α-type thionolite containing Ca).

[0109] Next, 3.2 ml of 50% hydrofluoric acid and 0.8 ml of 70% nitric acid were mixed to prepare a stock solution. 396 ml of distilled water was added to the stock solution to dilute its concentration to 1.0%, preparing 400 ml of a mixed acid aqueous solution. 30 g of the phosphor powder composed of α-type silon phosphor particles was added to this mixed acid aqueous solution. The temperature of the mixed acid aqueous solution was maintained at 80°C, and the solution was stirred using a magnetic stirrer at a rotation speed of 450 rpm while simultaneously undergoing an acid treatment for 30 minutes. The acid-treated powder was thoroughly rinsed with distilled water, filtered, dried, and then passed through a 45 μm mesh sieve to prepare the phosphor powder composed of α-type silon phosphor particles of Example 1.

[0110] The particle size, diffusion reflectance, and luminescence properties of the obtained phosphor powder were measured using the same method as in Examples 1-4.

[0111] Information related to Experiments 1 and 2 is summarized in Table 2 below.

[0112] [Table 2]

[0113]

[0114] As can be understood from the results of the additional embodiments, by changing the conditions and composition of acid treatment using high-speed stirring, a diffusion reflectance of around 99% can be achieved. Furthermore, the phosphor powder obtained in this way exhibits excellent fluorescence properties.

[0115] (Additional experiments related to changes in acid treatment conditions and the resulting changes in the final products)

[0116] In Example 2, the stirring speed using a magnetic stirrer was changed from 450 rpm to the usual 200 rpm. Otherwise, a phosphor powder composed of α-type thionyl phosphor particles was prepared in the same manner as in Example 2. For this phosphor powder, particle size distribution, diffusion reflectance measurement, and luminescence properties were evaluated in the same manner as in Examples 1-4. The results of Example 2 and the evaluation are shown in the table below.

[0117] [Table 3]

[0118]

[0119] By changing the stirring speed of the acid treatment from 450 rpm in Example 2 to 200 rpm, the diffuse reflectance of light with a wavelength of 600 nm decreased from 94.8% to 93.5%. In addition, the difference between the diffuse reflectance at 800 nm and the diffuse reflectance at 600 nm increased from 2.2% to 3.1%.

[0120] That is, as can be understood from the additional experiments, by carefully setting the stirring conditions of the acid treatment, phosphor powder with a large diffusion reflectance for light at a wavelength of 600 nm and / or a small difference between the diffusion reflectance at 800 nm and the diffusion reflectance at 600 nm can be obtained.

[0121] This application claims priority based on Japanese Patent Application No. 2019-069116, filed on March 29, 2019, the entire disclosure of which is incorporated herein by reference.

[0122] Symbol Explanation

[0123] 1 α-type thionolite particles

[0124] 30 Sealing material

[0125] 40 complex

[0126] 100 Light-emitting devices

[0127] 120 Light-emitting element

[0128] 130 radiator

[0129] 140 housing

[0130] 150 First lead frame

[0131] 160 Second lead frame

[0132] 170 joint line

[0133] 172 Joint line

Claims

1. A phosphor powder composed of α-type thionolite phosphor particles containing Eu. The Eu-containing α-type cerion phosphor particles are composed of Eu-containing α-type cerion phosphors, which are derived from the general formula: (M1) x M2 y Eu z (Si) 12－（m＋n） Al m＋n (O) n N 16－n The expression indicates that, in the general formula, M1 is monovalent Li, M2 is divalent Ca, x=0, 0<y<2.0, 0<z≤0.5, 0<x+y, 0.3≤x+y+z≤2.0, 0<n≤3.0, and it has an emission peak wavelength in the wavelength region above 590nm. The median particle size D of the volume standard determined by laser diffraction scattering method 50 The size is 10μm to 20μm. The diffusion reflectance of light with a wavelength of 600nm is 94%–99%. The difference between the diffuse reflectance X1 for light with a wavelength of 800 nm and the diffuse reflectance X2 for light with a wavelength of 600 nm, i.e., X1 - X2, is less than 3.0%. The units of diffuse reflectance X1 and diffuse reflectance X2 are %. Let the cumulative 10% particle size and the cumulative 90% particle size of the volume reference determined by laser diffraction scattering be set as D respectively. 10 D 90 At that time, (D) 90 -D 10 ) / D 50 It ranges from 1.0 to 1.

5.

2. A phosphor powder composed of α-type thionyl phosphor particles containing Eu. The Eu-containing α-type cerion phosphor particles are composed of Eu-containing α-type cerion phosphors, which are derived from the general formula: (M1) x M2 y Eu z (Si) 12－（m＋n） Al m＋n (O) n N 16－n The expression indicates that, in the general formula, M1 is a monovalent Li element, M2 is a divalent Ca element, x=0, 0<y<2.0, 0<z≤0.5, 0<x+y, 1.5<x+y+z≤2.0, 0<m≤4.0, and 0<n≤3.

0. The median particle size D of the volume standard determined by laser diffraction scattering method 50 The size is 10μm to 20μm. The diffusion reflectance of light with a wavelength of 600nm is 94%–99%. The difference between the diffuse reflectance X1 for light with a wavelength of 800 nm and the diffuse reflectance X2 for light with a wavelength of 600 nm, i.e., X1 - X2, is less than 3.0%. The units of diffuse reflectance X1 and diffuse reflectance X2 are %. Let the cumulative 10% particle size and the cumulative 90% particle size of the volume reference determined by laser diffraction scattering be set as D respectively. 10 D 90 At that time, (D) 90 -D 10 ) / D 50 It ranges from 1.0 to 1.

5.

3. The phosphor powder according to claim 2, wherein, It has emission peak wavelengths in the wavelength region above 590nm.

4. The phosphor powder according to any one of claims 1 to 3, wherein, The diffuse reflectance of light with a wavelength of 500nm is 66% to 80%.

5. A composite comprising the phosphor powder according to any one of claims 1 to 4 and a sealing material for sealing the phosphor powder.

6. A light-emitting device, comprising: A light-emitting element that emits excitation light; and The composite of claim 5 that converts the wavelength of the excitation light.

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