Phosphor powder, composite, and light-emitting device

Abstract

To provide phosphor powder which enables a light-emitting device improved in luminance to be provided.SOLUTION: The phosphor powder contains SCASN phosphor particles. The SCASN phosphor particles include phosphor particles (S) in which an SB area ratio to SA is 10.00% or less, in which SA denotes an area of a region (A) having a relative characteristic X-ray intensity of 0.5 or more when a maximum value of a characteristic X-ray intensity is 1.0 and SB denotes an area of a region (B) having a relative characteristic X-ray intensity of 0.8 or more in an element mapping image of SB measured under the following measuring conditions by an electron beam microanalyzer (EPMA). (Measuring conditions) acceleration voltage: 15 kV irradiation current: 50 nA beam diameter: O μm measurement time: 30 msec measurement region: 160 μm×160 μm measurement interval: 0.40 μm×0.40 μm measurement points: 400×400.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a phosphor powder, a composite, and a light-emitting device. [Background technology]

[0002] To manufacture white LEDs, research is being conducted into red phosphors that convert blue light from blue LED chips into red light, such as SCASN.

[0003] Patent Document 1 discloses a nitride phosphor having a general formula M a Sr b Ca c Al d Si e N f It contains a crystalline phase expressed by 4000mW / mm 2 The phosphor is characterized by a quantum efficiency maintenance rate of 85% or more when excited by light. In this general formula, M represents an activator element; <a<0.05、0.95≦b≦1、0≦c<0.1、a+b+c=1、0.7≦d≦1.3、0.7≦e≦1.3、2.5≦f≦3.5である。 [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-077800 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a phosphor powder and a composite that can provide a light emitting device with improved brightness, and a light emitting device with improved brightness. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, they have discovered a phosphor powder containing SCASN phosphor particles, wherein the SCASN phosphor particles have an area of ​​S in an elemental mapping image of Sr measured by an electron probe microanalyzer (EPMA) under specific measurement conditions, where the area of ​​a region (A) where the relative characteristic X-ray intensity is 0.5 or more when the maximum value of the characteristic X-ray intensity is 1.0 is S A The area of ​​the region (B) where the relative characteristic X-ray intensity is 0.8 or more is S B Then, S A S against B The present inventors have found that a phosphor powder containing phosphor particles (S) in which the area ratio of is 10.00% or less can improve the brightness of a light-emitting device obtained from the phosphor powder, and have completed the present invention.

[0007] According to the present invention, there are provided the following phosphor powder, composite body, and light-emitting device.

[0008] [1] A phosphor powder comprising SCASN phosphor particles, The SCASN phosphor particles are determined by measuring the area of ​​a region (A) where the relative characteristic X-ray intensity is 0.5 or more when the maximum value of the characteristic X-ray intensity is 1.0 in an elemental mapping image of Sr measured by an electron probe microanalyzer (EPMA) under the following measurement conditions: A The area of ​​the region (B) where the relative characteristic X-ray intensity is 0.8 or more is S B Then, S A S against B The phosphor powder contains phosphor particles (S) having an area ratio of 10.00% or less. (Measurement conditions) Accelerating voltage: 15 kV Irradiation current: 50nA Beam diameter: 0 μm Measurement time: 30msec Measurement area: 160μm x 160μm Measurement interval: 0.40μm×0.40μm Number of measurement points: 400 x 400 [2] The phosphor powder according to [1], wherein the proportion of the phosphor particles (S) in the SCASN phosphor particles is 0.5% or more and 50.0% or less. [3] The phosphor powder according to [1] or [2], wherein the SCASN phosphor particles contain columnar phosphor particles. [4] General formula, Eu a Sr b Ca c AlSi e N f O g The phosphor powder according to any one of [1] to [3], which contains phosphor particles represented by 0 < a < 1.000, 0 < b < 1.000, 0 < c < 1.000, 0.700 < a + b + c < 1.300, 0.700 < e < 1.300, 0 < f < 3.000, 0 < g < 3.000, 2.500 < f + g < 3.500. [5] The phosphor powder according to [4], wherein a < 0.300. [6]<00​​​​​​​​​​​​​​​​​​​​​​​​​​In the volume frequency particle size distribution of the phosphor powder by the laser diffraction scattering method, the particle diameter D at which the cumulative value reaches 10% 10 , 90% particle diameter D 90 , median diameter D 50 Regarding (D 90 -D 10 ) / D 50 The phosphor powder according to any one of [1] to

[10] , wherein the value is 0.50 or more and 1.50 or less.

[12] The phosphor powder according to any one of [1] to

[11] , wherein the total luminous flux and chromaticity y measured by the following method are expressed as a ratio of total luminous flux / chromaticity y of 370 lm or more. (method) The phosphor powder and silicone resin are mixed in a mixer so that the phosphor powder is 10% by mass, resulting in a composite. An LED with a peak wavelength of 455 nm is then placed at the bottom of the recessed package, and the LED is wire-bonded to an electrode on the substrate of the recessed package. The composite is then poured into the recess of the recessed package and cured at 150°C, resulting in a light-emitting device. The total luminous flux (lm) and chromaticity (y) of the light-emitting device are then measured using a total luminous flux meter.

[13] The phosphor powder according to

[12] , wherein the chromaticity y is 0.000 or more and 0.400 or less.

[14] A composite comprising the phosphor powder according to any one of [1] to

[13] and a sealant that seals the phosphor powder.

[15] a light emitting element that emits excitation light;

[14] A complex according to

[14] , which converts the wavelength of the excitation light; A light emitting device comprising: [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a phosphor powder and a composite that can provide a light emitting device with improved brightness, and a light emitting device with improved brightness. [Brief explanation of the drawings]

[0010] [Figure 1] This is a schematic cross-sectional view schematically showing an example of the structure of the light-emitting device of the present embodiment.

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. To avoid complexity, when there are a plurality of the same components in the same drawing, only one of them may be denoted by a reference numeral, and not all of them may be denoted by a reference numeral. The drawings are for illustrative purposes only. The shapes and dimensional ratios of the respective members in the drawings do not necessarily correspond to actual articles.

[0012] In the present embodiment, "A to B" indicating a numerical range represents A or more and B or less unless otherwise specified.

[0013] <Phosphor Powder> The phosphor powder of the present embodiment contains SCASN phosphor particles. The SCASN phosphor particles of the present embodiment are composed of the bonding of (Si,Al)-N4 regular tetrahedrons, and a part of the Ca atoms located in the gaps of the skeleton is substituted and solid-dissolved by Sr atoms, and further, a part of Ca 2+ acts as a luminescence center and is substituted by an activating element such as Eu 2+ and is a phosphor particle.

[0014] <SCASN Phosphor Particles> The SCASN phosphor particles of the present embodiment have an area S of a region (A) where the relative characteristic X-ray intensity is 0.5 or more when the maximum value of the characteristic X-ray intensity is set to 1.0 in the Sr element mapping image measured by an electron probe microanalyzer (EPMA). A When the area of the region (B) where the relative characteristic X-ray intensity is 0.8 or more is S B and S A is S with respect to S B and contains phosphor particles (S) having an area ratio of 10.00% or less.

[0015] According to the investigations of the present inventors, it has been found that in phosphor powders containing SCASN phosphor particles, there is a correlation between the area of ​​the region where the relative characteristic X-ray intensity is 0.8 or more in an elemental mapping image of Sr measured by an electron probe microanalyzer (EPMA) and the brightness of a light-emitting device obtained from the phosphor powder. As a result of further investigations by the inventors based on the above findings, it has been found that the area of ​​the region (A) where the relative characteristic X-ray intensity is 0.5 or more when the maximum value of the characteristic X-ray intensity is 1.0 in an elemental mapping image of Sr measured by an electron probe microanalyzer (EPMA) under specific measurement conditions is S A The area of ​​the region (B) where the relative characteristic X-ray intensity is 0.8 or more is S B Then, S A S against B The inventors have found that the brightness of a light-emitting device obtained from a phosphor powder can be improved by including phosphor particles (S) having an area ratio of 10.00% or less, and have completed the present invention.

[0016] <Phosphor particles (S)> S of the phosphor particles (S) of this embodiment A S against B From the viewpoint of further improving the brightness of the light emitting device, the area ratio of is preferably 0.0001% or more, more preferably 0.001% or more, even more preferably 0.005% or more, even more preferably 0.01% or more, even more preferably 0.03% or more, even more preferably 0.05% or more, and even more preferably 0.07% or more, and is preferably 10.00% or less, more preferably 7.00% or less, even more preferably 5.00% or less, even more preferably 3.00% or less, even more preferably 2.00% or less, even more preferably 1.00% or less, even more preferably 0.50% or less, even more preferably 0.30% or less, even more preferably 0.20% or less, and even more preferably 0.15% or less. In addition, S of the phosphor particles (S) of this embodiment A S against BFrom the viewpoint of further improving the brightness of the light emitting device, the area ratio of is preferably 0.0001% or more and 10.00% or less, more preferably 0.001% or more and 7.00% or less, even more preferably 0.005% or more and 5.00% or less, even more preferably 0.01% or more and 3.00% or less, even more preferably 0.03% or more and 2.00% or less, even more preferably 0.05% or more and 1.00% or less, even more preferably 0.07% or more and 0.50% or less, even more preferably 0.07% or more and 0.30% or less, even more preferably 0.07% or more and 0.20% or less, and even more preferably 0.07% or more and 0.15% or less.

[0017] In this embodiment, S A S against B The area ratio can be measured, for example, by the following method. First, an elemental mapping image of Sr is prepared for the phosphor powder using an electron beam microanalyzer under the following conditions: acceleration voltage 15 kV, irradiation current 50 nA, beam diameter 0 μm, measurement time 30 msec, measurement area 160 μm × 160 μm, measurement interval 0.40 μm × 0.40 μm, and number of measurement points 400 × 400. Next, for each elemental mapping image prepared, the area (S) of the region (A) where the relative characteristic X-ray intensity is 0.5 or more when the maximum value of the characteristic X-ray intensity is 1.0 is calculated. A ), the area (S B ) are measured by image analysis. A and S B From S A S against B Calculate the area ratio.

[0018] In this embodiment, a method for determining whether or not the phosphor powder contains phosphor particles (S) is, for example, A S against B The method for measuring the area ratio of S was repeated for 100 different fields of view. A S against B If the sample contains one or more phosphor particles with an area ratio of 10.00% or less, it is determined to contain phosphor particles (S), and S AS against B For example, if the sample does not contain any phosphor particles having an area ratio of 10.00% or less, it is determined that the sample does not contain any phosphor particles (S).

[0019] From the viewpoint of further improving the brightness of the light emitting device, the number ratio of the phosphor particles (S) in the SCASN phosphor particles of this embodiment is preferably 0.5% or more, more preferably 1.0% or more, even more preferably 1.5% or more, and is preferably 50.0% or less, more preferably 40.0% or less, even more preferably 30.0% or less, even more preferably 20.0% or less, even more preferably 10.0% or less, even more preferably 5.0% or less. Furthermore, from the viewpoint of further improving the brightness of the light emitting device, the proportion of the number of phosphor particles (S) in the SCASN phosphor particles of this embodiment is preferably 0.5% or more and 50.0% or less, more preferably 1.0% or more and 40.0% or less, even more preferably 1.5% or more and 30.0% or less, even more preferably 1.5% or more and 20.0% or less, even more preferably 1.5% or more and 10.0% or less, and even more preferably 1.5% or more and 5.0% or less.

[0020] The SCASN phosphor particles of this embodiment preferably contain columnar phosphor particles, from the viewpoint of further improving the brightness of the light emitting device.

[0021] The phosphor powder of this embodiment can be obtained by appropriately selecting the raw materials, the ratio of each raw material used, the manufacturing procedure and manufacturing conditions, etc. Regarding the selection of raw materials and the ratio of raw materials, it is preferable to use a larger amount of Sr-containing raw material and a smaller amount of Eu-containing raw material, and to add "core particles." Regarding the manufacturing procedure and manufacturing conditions, it is preferable to perform firing in a sealed container and to perform atmospheric heat treatment. Details of these will be described later.

[0022] <Crystal structure, elemental composition, etc.> From the viewpoint of further improving the brightness of the light emitting device, the phosphor powder of this embodiment is preferably represented by the general formula: Eu a Sr bCa c AlSi e N f O g It is represented by 0 < a < 1.000, 0 ≦ b < 1.000, 0 ≦ c < 1.000, 0.700 < a + b + c < 1.300, 0.700 < e < 1.300, 0 ≦ f ≦ 3.000, 0 ≦ g ≦ 3.000, 2.500 ≦ f + g ≦ 3.500, and includes phosphor particles.

[0023] The crystal phase can be confirmed by powder X-ray diffraction. A single crystal phase is preferred for the crystal phase, but it may contain different phases as long as it does not significantly affect the phosphor characteristics. The presence or absence of different phases can be determined, for example, by the presence or absence of peaks other than those due to the target crystal phase by powder X-ray diffraction.

[0024] Regarding a, from the viewpoint of further improving the luminance of the light-emitting device, preferably 0.001 < a, and preferably a < 0.300, more preferably a < 0.200, still more preferably a < 0.100, still more preferably a < 0.050, still more preferably a < 0.010, still more preferably a < 0.008, still more preferably a < 0.006, still more preferably a < 0.005. Regarding a, from the viewpoint of further improving the luminance of the light-emitting device, preferably 0.001 < a < 0.300, more preferably 0.001 < a < 0.200, still more preferably 0.001 < a < 0.100, still more preferably 0.001 < a < 0.050, still more preferably 0.001 < a < 0.010, still more preferably 0.001 < a < 0.008, still more preferably 0.001 < a < 0.006, still more preferably 0.001 < a < 0.005.

[0025] Regarding b, from the viewpoint of further improving the luminance of the light-emitting device, preferably 0 < b, more preferably 0.500 < b, still more preferably 0.800 < b, still more preferably​Regarding b, from the perspective of further improving the luminance of the light-emitting device, preferably 0 < b < 0.995, more preferably 0.500 < b < 0.995, still more preferably 0.800 < b < 0.990, still more preferably 0.900 < b < 0.990, still more preferably 0.930 < b < 0.985, still more preferably 0.950 < b < 0.985.

[0026] As another index from the perspective of "a large amount of Sr", the molar ratio of b / (b + c) is preferably 0.960 or more, more preferably 0.965 or more, still more preferably 0.970 or more, and preferably 0.990 or less, more preferably 0.985 or less, still more preferably 0.980 or less, from the perspective of further improving the luminance of the light-emitting device. Regarding the molar ratio of b / (b + c), from the perspective of further improving the luminance of the light-emitting device, it is preferably 0.960 or more and 0.990 or less, more preferably 0.965 or more and 0.985 or less, still more preferably 0.970 or more and 0.980 or less.

[0027] Regarding c, from the perspective of further improving the luminance of the light-emitting device, preferably 0 < c < 0.500, more preferably 0.001 < c < 0.300, still more preferably 0.005 < c < 0.200, still more preferably 0.010 < c < 0.100, still more preferably 0.015 < c < 0.050, still more preferably 0.020 < c < 0.030.

[0028] Regarding e, from the perspective of further improving the luminance of the light-emitting device, preferably 0.750 < e < 1.200, more preferably 0.800 < e < 1.100, still more preferably 0.850 < e < 1.000, still more preferably 0.870 < e < 0.970.

[0029] Regarding f, from the viewpoint of further improving the luminance of the light-emitting device, preferably 0 < f < 3.000, more preferably 1.000 < f < 3.000, still more preferably 2.000 < f < 2.990, still more preferably 2.500 < f < 2.990, still more preferably 2.800 < f < 2.980, still more preferably 2.900 < f < 2.980.

[0030] Regarding g, from the viewpoint of further improving the luminance of the light-emitting device, preferably 0 < g < 3.000, more preferably 0.001 < g < 2.000, still more preferably 0.010 < g < 1.000, still more preferably 0.030 < g < 0.500, still more preferably 0.040 < g < 0.300, still more preferably 0.050 < g < 0.100, still more preferably 0.060 < g < 0.070.

[0031] Regarding a + b + c, from the viewpoint of further improving the luminance of the light-emitting device, preferably 0.800 < a + b + c < 1.200, more preferably 0.850 < a + b + c < 1.150, still more preferably 0.900 < a + b + c < 1.100, still more preferably 0.950 < a + b + c < 1.050, still more preferably 0.970 < a + b + c < 1.030.

[0032] Regarding f + g, from the viewpoint of further improving the luminance of the light-emitting device, preferably 2.700 < f + g < 3.300, more preferably 2.800 < f + g < 3.200, still more preferably 2.900 < f + g < 3.100, still more preferably 2.950 < f + g < 3.070, still more preferably 2.980 < f + g < 3.050.

[0033] [[ID=1,6]]In this embodiment, among the molar ratios of the respective elements contained in the phosphor powder, the molar ratios of Eu, Sr, Ca, Al, and Si can be measured, for example, by dissolving the phosphor powder by a pressurized acid decomposition method to prepare a sample solution and performing quantitative analysis of the elements on the obtained sample solution using an ICP emission spectroscopic analyzer. In this embodiment, the molar ratio of N and O among the molar ratios of each element contained in the phosphor powder can be determined, for example, by weighing out 0.03 g of the phosphor powder and measuring the oxygen and nitrogen contents using an oxygen / nitrogen analyzer.

[0034] <Particle size> The volume-based median diameter D of the phosphor powder of this embodiment measured by the laser diffraction scattering method 50 From the viewpoint of further improving the brightness of the light-emitting device, the thickness is preferably 15.0 μm or more, more preferably 18.0 μm or more, even more preferably 21.0 μm or more, even more preferably 23.0 μm or more, even more preferably 24.0 μm or more, and is preferably 35.0 μm or less, more preferably 32.0 μm or less, even more preferably 30.0 μm or less, even more preferably 28.0 μm or less, even more preferably 27.5 μm or less. In addition, the volume-based median diameter D of the phosphor powder of this embodiment measured by the laser diffraction scattering method is 50 From the viewpoint of further improving the brightness of the light-emitting device, the thickness is preferably 15.0 μm or more and 35.0 μm or less, more preferably 18.0 μm or more and 32.0 μm or less, even more preferably 21.0 μm or more and 30.0 μm or less, even more preferably 23.0 μm or more and 28.0 μm or less, and even more preferably 24.0 μm or more and 27.5 μm or less.

[0035] In the volume frequency particle size distribution of the phosphor powder of this embodiment by the laser diffraction scattering method, the particle diameter D at which the cumulative value reaches 10% 10 From the viewpoint of further improving the brightness of the light-emitting device, the thickness is preferably 10.0 μm or more, more preferably 11.0 μm or more, even more preferably 12.0 μm or more, even more preferably 13.0 μm or more, and even more preferably 14.0 μm or more, and is preferably 20.0 μm or less, more preferably 18.0 μm or less, even more preferably 17.0 μm or less, even more preferably 16.0 μm or less, and even more preferably 15.5 μm or less. In addition, in the volume frequency particle size distribution of the phosphor powder of this embodiment by the laser diffraction scattering method, the particle diameter D at which the cumulative value reaches 10% 10From the viewpoint of further improving the brightness of the light-emitting device, the thickness is preferably 10.0 μm or more and 20.0 μm or less, more preferably 11.0 μm or more and 18.0 μm or less, even more preferably 12.0 μm or more and 17.0 μm or less, even more preferably 13.0 μm or more and 16.0 μm or less, and even more preferably 14.0 μm or more and 15.5 μm or less.

[0036] In the volume frequency particle size distribution of the phosphor powder of this embodiment by the laser diffraction scattering method, the particle diameter D at which the cumulative value reaches 90% 90 From the viewpoint of further improving the brightness of the light-emitting device, is preferably 30.0 μm or more, more preferably 35.0 μm or more, even more preferably 38.0 μm or more, even more preferably 40.0 μm or more, even more preferably 42.0 μm or more, even more preferably 43.0 μm or more, and is preferably 60.0 μm or less, more preferably 55.0 μm or less, even more preferably 52.0 μm or less, even more preferably 50.0 μm or less, even more preferably 48.0 μm or less, even more preferably 46.0 μm or less. In addition, in the volume frequency particle size distribution of the phosphor powder of this embodiment by the laser diffraction scattering method, the particle diameter D at which the cumulative value reaches 90% 90 From the viewpoint of further improving the brightness of the light-emitting device, the thickness is preferably 30.0 μm or more and 60.0 μm or less, more preferably 35.0 μm or more and 55.0 μm or less, even more preferably 38.0 μm or more and 52.0 μm or less, even more preferably 40.0 μm or more and 50.0 μm or less, even more preferably 42.0 μm or more and 48.0 μm or less, and even more preferably 43.0 μm or more and 46.0 μm or less.

[0037] In the volume frequency particle size distribution of the phosphor powder of this embodiment, measured by the laser diffraction scattering method, (D 90 -D 10 ) / D 50From the viewpoint of further improving the luminance of the light-emitting device, the value of is preferably 0.50 or more, more preferably 0.70 or more, even more preferably 0.90 or more, even more preferably 1.00 or more, even more preferably 1.05 or more, even more preferably 1.10 or more, and is preferably 1.50 or less, more preferably 1.40 or less, even more preferably 1.35 or less, even more preferably 1.30 or less, even more preferably 1.25 or less, even more preferably 1.20 or less. In addition, the volume frequency particle size distribution of the phosphor powder of this embodiment, as measured by the laser diffraction scattering method, is (D 90 -D 10 ) / D 50 From the viewpoint of further improving the luminance of the light-emitting device, the value of is preferably 0.50 or more and 1.50 or less, more preferably 0.70 or more and 1.40 or less, even more preferably 0.90 or more and 1.35 or less, even more preferably 1.00 or more and 1.30 or less, even more preferably 1.05 or more and 1.25 or less, and even more preferably 1.10 or more and 1.20 or less.

[0038] In this embodiment, D 50 , D 10 and D 90 The particle size distribution can be adjusted by appropriately applying known means such as pulverization, sieving, etc. Details will be described later.

[0039] <Internal quantum efficiency> The internal quantum efficiency of the phosphor powder of this embodiment when irradiated with light having a wavelength of 455 nm is preferably 87.0% or more, and more preferably 88.0% or more, from the viewpoint of further improving the brightness of the light emitting device. The upper limit of the internal quantum efficiency of the phosphor powder of this embodiment is not particularly limited, and may be, for example, 98.0% or less, 95.0% or less, 93.0% or less, or 91.0% or less. Furthermore, from the viewpoint of further improving the brightness of the light emitting device, the internal quantum efficiency of the phosphor powder of this embodiment when irradiated with light having a wavelength of 455 nm is preferably 87.0% or more and 98.0% or less, more preferably 87.0% or more and 95.0% or less, even more preferably 88.0% or more and 93.0% or less, and even more preferably 88.0% or more and 91.0% or less.

[0040] <External quantum efficiency> The external quantum efficiency of the phosphor powder of this embodiment when irradiated with light having a wavelength of 455 nm is preferably 77.0% or more, more preferably 78.0% or more, and even more preferably 78.5% or more, from the viewpoint of further improving the brightness of the light emitting device. The upper limit of the external quantum efficiency of the phosphor powder of this embodiment is not particularly limited, and may be, for example, 98.0% or less, 95.0% or less, 90.0% or less, or 87.0% or less. Furthermore, from the viewpoint of further improving the brightness of the light emitting device, the external quantum efficiency of the phosphor powder of this embodiment when irradiated with light having a wavelength of 455 nm is preferably 77.0% or more and 98.0% or less, more preferably 77.0% or more and 95.0% or less, even more preferably 78.0% or more and 90.0% or less, and even more preferably 78.5% or more and 87.0% or less.

[0041] In this embodiment, the internal quantum efficiency and external quantum efficiency of the phosphor powder can be measured by, for example, the following method. First, the fluorescence spectrum of the phosphor powder is measured for light with an excitation wavelength of 455 nm using a spectrofluorometer calibrated with rhodamine B and a secondary standard light source. Next, the emission intensity of the phosphor powder is determined from the fluorescence spectrum data, and the number of reflected excitation light photons (Qref) and the number of fluorescence photons (Qem) are calculated. The number of reflected excitation light photons is calculated in the wavelength range of 450 to 465 nm, and the number of fluorescence photons is calculated in the range of 465 to 800 nm. Using the same device, a standard reflector with a reflectance of 99% is attached to the opening of the integrating sphere to measure the spectrum of excitation light with a wavelength of 455 nm. Then, the number of excitation light photons (Qex) is calculated from the spectrum in the wavelength range of 450 to 465 nm. From the above calculation results, the internal quantum efficiency and external quantum efficiency of the phosphor powder for light of 455 nm are calculated based on the following formulas. Internal quantum efficiency = (Qem / (Qex-Qref)) x 100 External quantum efficiency = (Qem / Qex) x 100

[0042] <Total luminous flux, chromaticity y> With respect to the total luminous flux and chromaticity y of the phosphor powder of this embodiment measured by the following method, the value of total luminous flux / chromaticity y is preferably 370 lm or more, more preferably 375 lm or more, even more preferably 380 lm or more, even more preferably 390 lm or more, and even more preferably 400 lm or more, from the viewpoint of further improving the luminance of the light emitting device. The upper limit of the value of total luminous flux / chromaticity y of the phosphor powder of this embodiment is not particularly limited, and may be, for example, 1000 lm or less, 800 lm or less, or 500 lm or less. Furthermore, with regard to the total luminous flux and chromaticity y of the phosphor powder of this embodiment, measured by the following method, the value of total luminous flux / chromaticity y is preferably 370 lm or more and 1000 lm or less, more preferably 375 lm or more and 1000 lm or less, even more preferably 380 lm or more and 800 lm or less, even more preferably 390 lm or more and 800 lm or less, and even more preferably 400 lm or more and 500 lm or less, from the viewpoint of further improving the brightness of the light-emitting device. (method) The phosphor powder and silicone resin are mixed in a mixer so that the phosphor powder is 10% by mass, resulting in a composite. An LED with a peak wavelength of 455 nm is then placed at the bottom of the recessed package, and the LED is wire-bonded to the electrode on the substrate of the recessed package. The composite is then poured into the recess of the recessed package and cured at 150°C, resulting in a light-emitting device. The total luminous flux (lm) and chromaticity y of the light-emitting device are then measured using a total luminous flux meter.

[0043] Here, total luminous flux (lm) is a physical property that is affected by the value of chromaticity y. In other words, even if the luminance is the same, the greater the chromaticity y, the greater the value of total luminous flux (lm). Therefore, the luminance of a light emitting device can be evaluated based on the value of total luminous flux / chromaticity y (lm), which is obtained by dividing total luminous flux (lm) by chromaticity y.

[0044] From the viewpoint of further improving the brightness of the light-emitting device, the chromaticity y of the phosphor powder of this embodiment obtained by the above method is preferably 0.100 or more, more preferably 0.150 or more, even more preferably 0.180 or more, and is preferably 0.400 or less, more preferably 0.350 or less, even more preferably 0.300 or less, even more preferably 0.250 or less. Furthermore, from the viewpoint of further improving the brightness of the light-emitting device, the chromaticity y of the phosphor powder of this embodiment obtained by the above method is preferably 0.100 or more and 0.400 or less, more preferably 0.100 or more and 0.350 or less, even more preferably 0.150 or more and 0.300 or less, and even more preferably 0.180 or more and 0.250 or less.

[0045] From the viewpoint of further improving the brightness of the light emitting device, the total luminous flux of the phosphor powder of this embodiment obtained by the above method is preferably 50 lm or more, more preferably 60 lm or more, even more preferably 70 lm or more, and even more preferably 75 lm or more. The upper limit of the total luminous flux of the phosphor powder of this embodiment is not particularly limited, and may be, for example, 200 lm or less, 150 lm or less, 100 lm or less, or 90 lm or less. Furthermore, from the viewpoint of further improving the brightness of the light-emitting device, the total luminous flux of the phosphor powder of this embodiment obtained by the above method is preferably 50 lm or more and 200 lm or less, more preferably 60 lm or more and 150 lm or less, even more preferably 70 lm or more and 100 lm or less, and even more preferably 75 lm or more and 90 lm or less.

[0046] <Method of manufacturing phosphor powder> The phosphor powder of this embodiment can be obtained by appropriately selecting raw materials, the ratio of each raw material used, the manufacturing procedure and manufacturing conditions, etc. Specifically, the phosphor powder of this embodiment is preferably a mixing step of mixing the starting materials to obtain a raw material mixed powder; a firing step of firing the raw material powder mixture to obtain a lumpy fired powder; A powdering process for powdering the lump fired powder; an acid treatment step of treating the powdered fired powder with an acid to obtain an acid-treated powder; an elutriation step for removing fine particles from the acid-treated powder by elutriation; an atmospheric heat treatment step of atmospherically heat treating the acid-treated powder to obtain atmospherically heat-treated powder; The phosphor powder can be produced through the steps described above. In addition, the phosphor powder may be produced through additional steps other than those described above.

[0047] <Mixing process> In the mixing step of this embodiment, the starting materials are mixed to form a raw material mixed powder. From the viewpoint of further improving the brightness of the light-emitting device, the starting materials of this embodiment preferably contain all of a europium compound, a strontium compound, a calcium compound, silicon nitride, and aluminum nitride, and more preferably contain all of europium oxide, strontium nitride, calcium nitride, silicon nitride, and aluminum nitride. The starting materials of this embodiment are preferably in the form of powder.

[0048] From the viewpoint of further improving the brightness of the light-emitting device, the europium compound of this embodiment preferably contains one selected from the group consisting of europium oxide, europium nitride, and europium fluoride, and more preferably contains europium oxide alone.

[0049] In the firing process of this embodiment, europium is divided into those that form a solid solution, those that volatilize, and those that remain as heterogeneous phase components. The heterogeneous phase components containing europium can be removed by acid treatment or the like. However, if too much heterogeneous phase component containing europium is produced, an insoluble component is produced by acid treatment, resulting in a decrease in brightness. Furthermore, any heterogeneous phase that does not absorb excess light may remain, and europium may be contained in this heterogeneous phase.

[0050] The amount of the europium compound in this embodiment is preferably used in an amount such that, from the viewpoint of further improving the luminance of the light-emitting device, a in the above general formula in the charging ratio satisfies preferably 0.001 < a < 0.030, more preferably 0.001 < a < 0.010, still more preferably 0.001 < a < 0.008, and still more preferably 0.001 < a < 0.005. Incidentally, when the nuclear particles described later are used, the amount of europium in the nuclear particles is not included in a in the above inequality.

[0051] The amount of the strontium compound in this embodiment is preferably used in an amount such that, from the viewpoint of further improving the luminance of the light-emitting device, b in the above general formula in the charging ratio satisfies preferably 0.950 < b < 0.99, more preferably 0.970 < b < 0.980. Incidentally, when the nuclear particles described later are used, the amount of strontium in the nuclear particles is not included in b in the above inequality.

[0052] The amount of the calcium compound in this embodiment is preferably used in an amount such that, from the viewpoint of further improving the luminance of the light-emitting device, c in the above general formula in the charging ratio satisfies preferably 0.010 < c < 0.040, more preferably 0.015 < c < 0.030. Incidentally, when the nuclear particles described later are used, the amount of calcium in the nuclear particles is not included in c in the above inequality.

[0053] The starting material of this embodiment (the raw material mixed powder) preferably contains SCASN phosphor core particles having a median diameter of 10 μm or more and 30 μm or less. That is, it is preferable that a part of the starting material is SCASN phosphor core particles having a median diameter of 10 μm or more and 30 μm or less. From the viewpoint of further improving the light-emitting characteristics, the median diameter of the SCASN phosphor core particles of this embodiment is preferably 10 μm or more, more preferably 14 μm or more, still more preferably 16 μm or more, and preferably 30 μm or less, more preferably 25 μm or less, and still more preferably 20 μm or less. In this specification, the SCASN phosphor core particles are also simply referred to as "core particles", "core", etc.

[0054] Although the details are unclear, it is thought that by using core particles, crystallization will proceed from the core particles as the starting point during the subsequent firing process. Therefore, it is thought that the way crystals grow will be different from when the firing process is carried out without using core particles. As a result, it is thought that it will be easier to obtain phosphor powder with improved luminescence properties.

[0055] The core particles of this embodiment can be, for example, a phosphor powder represented by the same general formula as the phosphor powder of this embodiment described above.

[0056] When core particles are used, the amount thereof is, from the viewpoint of further improving the light-emitting properties, preferably 3 mass % or more, more preferably 5 mass % or more, even more preferably 8 mass % or more of the total amount of the raw material mixed powder, and preferably 30 mass % or less, more preferably 20 mass % or less, even more preferably 15 mass % or less, even more preferably 12 mass % or less.

[0057] The core particles can be obtained, for example, through substantially the same process as that for the phosphor powder of this embodiment. That is, in the manufacturing process of the phosphor powder of this embodiment, the core particles can be obtained in the same manner except that the core particles are not added in the mixing step. The composition (general formula) of the core particles is also preferably the same as that of the phosphor powder of this embodiment.

[0058] In the mixing step of this embodiment, the raw material mixed powder can be obtained, for example, by dry mixing the starting materials or by wet mixing the starting materials in an inert solvent that does not substantially react with the starting materials and then removing the solvent. Examples of mixing devices that can be used include a small mill mixer, a V-type mixer, a rocking mixer, a ball mill, and a vibration mill. After mixing using the device, aggregates can be removed using a sieve, if necessary, to obtain the raw material mixed powder. In order to prevent deterioration of the starting materials and unintended incorporation of oxygen, the mixing step of this embodiment is preferably carried out in a nitrogen atmosphere or in an environment with as little moisture (humidity) as possible.

[0059] <Firing process> In the firing step of this embodiment, the raw material mixed powder obtained in the mixing step is fired to obtain a fired powder. The firing temperature in the firing step of this embodiment is preferably 1850° C. or higher and 2000° C. or lower, more preferably 1900° C. or higher and 2050° C. or lower, from the viewpoint of further improving the luminance of the light emitting device.

[0060] The heating and holding time in the firing step of this embodiment is preferably 5 hours or more and 15 hours or less, more preferably 7 hours or more and 10 hours or less, from the viewpoint of further improving the luminance of the light emitting device. The pressure in the firing step of this embodiment is preferably 0.7 MPaG or more and 1.0 MPaG or less, more preferably 0.8 MPaG or more and 0.9 MPaG or less, from the viewpoint of further improving the luminance of the light emitting device. From the viewpoint of controlling the oxygen concentration, the firing step of this embodiment is preferably carried out in a nitrogen gas atmosphere, that is, in a nitrogen gas atmosphere with a pressure of 0.7 MPaG or more and 1.0 MPaG or less.

[0061] In the firing process of this embodiment, in order to further improve the brightness of the light-emitting device, it is preferable to heat the mixture in a container that is less likely to react with the raw material mixed powder during firing. Specifically, it is preferable to use a high-melting-point container, and more preferably a tungsten container. This can suppress the generation of heterogeneous phases.

[0062] In addition, in the firing step of this embodiment, from the viewpoint of further improving the brightness of the light-emitting device, it is preferable that the container be a sealed container with high airtightness. By firing the raw material mixed powder under sealed conditions, it is possible to prevent oxygen and moisture (humidity) from entering the container and suppress deterioration of the raw material mixed powder, thereby further improving the brightness of the light-emitting device. The sealed container preferably has a structure in which the interior of the container is sealed by narrowing the gap between the lid and the body of the container. As a method for narrowing the gap between the lid and the body of the sealed container, for example, a method in which the body and the lid of the container are fitted together can be mentioned, whereas conventional containers have a structure in which the lid is simply placed on the body.

[0063] <Powderization process> In the pulverization step of this embodiment, the sintered powder is first pulverized by using treatments such as crushing, grinding, and classification, either alone or in combination. The sintered powder obtained through the sintering step is usually a sintered block, so the sintered powder is pulverized to make it easier to handle.

[0064] A specific example of a method for the pulverization step of this embodiment is to pulverize the sintered body to a predetermined particle size using a general pulverizer such as a ball mill, a vibration mill, a jet mill, etc. However, care should be taken because excessive pulverization may produce fine particles that easily scatter light or may cause crystal defects on the particle surfaces, resulting in a decrease in luminous efficiency.

[0065] <Annealing process> In the annealing step of this embodiment, after the pulverization step, the sintered powder is annealed at a temperature lower than the sintering temperature in the sintering step. This can sufficiently improve the luminous efficiency of the phosphor powder, and also, since the rearrangement of the elements removes distortions and defects, the fluorescent properties of the phosphor powder can be further improved. On the other hand, the annealing step may produce heterogeneous phases, but these can be sufficiently removed by the acid treatment step described below.

[0066] In order to further improve the brightness of the light-emitting device, the annealing step of this embodiment is preferably performed in a hydrogen gas atmosphere, an argon atmosphere, or a mixed atmosphere of hydrogen gas and argon, and more preferably in an argon atmosphere. Also, in order to further improve the brightness of the light-emitting device, the annealing step of this embodiment is preferably performed under atmospheric pressure.

[0067] The heat treatment temperature in the annealing step of this embodiment is preferably 1250° C. or higher and 1450° C. or lower, more preferably 1300° C. or higher and 1400° C. or lower, from the viewpoint of further improving the luminance of the light emitting device. The heat treatment time in the annealing step of this embodiment is preferably 5 hours or more and 10 hours or less, more preferably 7 hours or more and 9 hours or less, from the viewpoint of further improving the luminance of the light emitting device.

[0068] In the annealing step of this embodiment, similarly to the firing step, it is preferable to heat the mixture by filling it into a container that is unlikely to react with the fired powder during heat treatment, for example, a high-melting-point container, specifically a container whose inner wall is made of tungsten. Furthermore, from the viewpoint of further improving the brightness of the light-emitting device, it is preferable that the container used in the annealing step is a sealed container as described above, and it is more preferable that both the containers used in the firing step and the annealing step are sealed containers.

[0069] <Acid treatment process> In the acid treatment step of this embodiment, the powdery fired powder is subjected to an acid treatment to obtain an acid-treated powder. This makes it possible to remove at least a portion of the impurities that do not contribute to light emission. Incidentally, it is presumed that the impurities that do not contribute to light emission are generated during the firing and annealing processes.

[0070] In the acid treatment step of this embodiment, an aqueous solution containing one or more acids selected from the group consisting of hydrofluoric acid, sulfuric acid, phosphoric acid, hydrochloric acid, and nitric acid can be used as the acid. In particular, from the viewpoint of further improving the brightness of the light-emitting device, the aqueous solution preferably contains one or more acids selected from the group consisting of hydrochloric acid, hydrofluoric acid, nitric acid, and a mixed acid of hydrofluoric acid and nitric acid, and more preferably contains hydrochloric acid.

[0071] The acid treatment step of this embodiment can be carried out by dispersing the calcined powder in an aqueous solution containing the acid. The stirring time is preferably 30 minutes to 3 hours, more preferably 45 minutes to 2 hours, from the viewpoint of further improving the brightness of the light-emitting device. The stirring temperature is preferably 50°C to 100°C, more preferably 60°C to 90°C, from the viewpoint of further improving the brightness of the light-emitting device.

[0072] After the acid treatment step of this embodiment, the liquid containing the dispersed annealed powder may be boiled, and substances other than the phosphor powder may be separated by filtration. If necessary, the substances adhering to the phosphor particles may be washed with water. After washing with water, the phosphor powder is usually dried by natural drying or drying in a dryer. The dried phosphor powder may be placed in a crucible and heated to modify the surface.

[0073] <Elutriation process> In the elutriation step of this embodiment, after the acid treatment step, fine particles are removed from the acid-treated powder by elutriation, which makes it possible to remove fine particles that may deteriorate the fluorescent properties of the phosphor powder, thereby further improving the fluorescent properties.

[0074] The elutriation process is carried out by adding the acid-treated powder to a dispersion medium, preparing a dispersion and stirring the mixture, then precipitating the acid-treated powder in the dispersion, and removing the supernatant. After removing the supernatant, the precipitate is collected by filtration and dried to obtain an acid-treated powder from which the fine particle powder has been removed. In the elutriation process, the preparation of the dispersion and the removal of the supernatant may be repeated. From the viewpoint of further improving the brightness of the light-emitting device, it is preferable to use an aqueous solution of sodium hexametaphosphate as the dispersion medium.

[0075] <Atmospheric heat treatment process> In the atmospheric heat treatment step of this embodiment, after the elutriation step, the acid-treated powder is subjected to atmospheric heat treatment to obtain atmospheric heat-treated powder. This further improves the fluorescent properties of the phosphor powder. On the other hand, since excessive atmospheric heat treatment reduces the fluorescent properties of the phosphor powder, it is important to perform atmospheric heat treatment under appropriate conditions in order to improve the brightness of the light-emitting device.

[0076] The atmospheric heat treatment step of this embodiment is preferably carried out in the atmosphere under atmospheric pressure, from the viewpoint of further improving the luminance of the light-emitting device. The heat treatment temperature in the atmospheric heat treatment step of this embodiment is preferably 350° C. or higher and 450° C. or lower, more preferably 380° C. or higher and 420° C. or lower, from the viewpoint of further improving the luminance of the light emitting device.

[0077] The heat treatment time in the atmospheric heat treatment step of this embodiment is preferably 30 minutes or more and 4 hours or less, more preferably 45 minutes or more and 3 hours or less, from the viewpoint of further improving the luminance of the light emitting device.

[0078] The temperature rise rate in the atmospheric heat treatment step of this embodiment is preferably 1° C. / min to 4° C. / min, more preferably 2° C. / min to 3° C. / min, from the viewpoint of further improving the luminance of the light emitting device.

[0079] <Complex> The composite of this embodiment includes, for example, the above-described phosphor powder and a sealant that seals the phosphor powder. In the composite of this embodiment, the above-described phosphor powder is dispersed in the sealant. From the viewpoint of further improving the brightness of the light-emitting device, the sealing material of this embodiment preferably contains one or more materials selected from the group consisting of silicone resin, epoxy resin, urethane resin, glass, and ceramics, and more preferably contains silicone resin.

[0080] From the viewpoint of further improving the brightness of the light emitting device, the content of the phosphor powder in the composite of this embodiment is preferably 1 mass % or more, more preferably 3 mass % or more, even more preferably 5 mass % or more, even more preferably 7 mass % or more, and preferably 20 mass % or less, more preferably 17 mass % or less, even more preferably 15 mass % or less, even more preferably 13 mass % or less, when the total amount of the composite is taken as 100 mass %. Furthermore, from the viewpoint of further improving the brightness of the light emitting device, the content of the phosphor powder in the composite of this embodiment is preferably 1% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 17% by mass or less, even more preferably 5% by mass or more and 15% by mass or less, and even more preferably 7% by mass or more and 13% by mass or less, when the total amount of the composite is taken as 100% by mass.

[0081] A method for producing the composite of this embodiment may include, for example, adding the phosphor powder of this embodiment to a liquid resin, glass, ceramics, etc., mixing them uniformly, and then curing or sintering them by heat treatment.

[0082] <Light-emitting device> The light emitting device of this embodiment includes a light emitting element that emits excitation light and the composite of this embodiment that converts the wavelength of the excitation light. The light emitting device of this embodiment will be described below with reference to Fig. 1, which is a schematic cross-sectional view showing an example of the structure of the light emitting device of this embodiment. As shown in Fig. 1, the light emitting device 100 includes a light emitting element 120, a heat sink 130, a case 140, a first lead frame 150, a second lead frame 160, bonding wires 170 and 172, and a composite 40.

[0083] The light emitting element 120 is mounted in a predetermined region on the upper surface of the heat sink 130. Mounting the light emitting element 120 on the heat sink 130 can improve the heat dissipation properties of the light emitting element 120. Note that a packaging substrate may be used instead of the heat sink 130.

[0084] The light emitting element 120 is a semiconductor element that emits excitation light. For example, an LED chip that emits light with a wavelength of 300 nm or more and 500 nm or less, which corresponds to near-ultraviolet to blue light, can be used as the light emitting element 120. One 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 a bonding wire 170 such as a gold wire. 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 via a bonding wire 172 such as a gold wire.

[0085] A generally funnel-shaped recess whose diameter gradually increases from the bottom toward the top is formed in case 140. Light emitting element 120 is provided on the bottom of the recess. The wall of the recess surrounding light emitting element 120 serves as a reflector.

[0086] The composite 40 is filled in the recess whose wall is formed by the case 140. The composite 40 is a wavelength conversion member that converts excitation light emitted from the light emitting element 120 into light with a longer wavelength. The composite of this embodiment is used as the composite 40, and the above-mentioned phosphor powder 1 is dispersed in an encapsulant 30 such as a resin. The light emitting device 100 emits a mixed color of light from the light emitting element 120 and light emitted from the phosphor powder 1 that is excited by absorbing the light from the light emitting element 120. Note that, in order to obtain a white mixed color (to make the light emitting device 100 a white LED), it is preferable that the composite 40 contains, for example, LuAG phosphor powder in addition to the phosphor powder 1 (it is preferable that LuAG phosphor powder is dispersed in the encapsulant 30 in addition to the phosphor powder 1). In this embodiment, the peak wavelength and half width of the fluorescence spectrum of the phosphor powder 1 are within certain numerical ranges, so that good white light can be easily obtained.

[0087] 1 shows a surface-mounted light-emitting device as an example, the light-emitting device is not limited to the surface-mounted type. The light-emitting device may be a bullet type, a COB (chip-on-board) type, a CSP (chip-scale package) type, or the like.

[0088] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

[0089] The embodiments of the present invention will be described in detail based on examples and comparative examples, but the present invention is not limited to the examples.

[0090] Example 1 <Preparation of core particles> First, 62.14 g of α-type silicon nitride (Si3N4, manufactured by Ube Industries, Ltd., SN-E10 grade), 54.47 g of aluminum nitride (AlN, manufactured by Tokuyama Corporation, E grade), and 0.94 g of europium oxide (Eu2O3, manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a container and premixed.

[0091] Next, in a glove box maintained in a nitrogen atmosphere with a moisture content of 1 mass ppm or less and an oxygen concentration of 50 mass ppm or less, 3.02 g of calcium nitride (CaN, manufactured by Materion) and 119.45 g of strontium nitride (SrN, manufactured by Kojundo Chemical Laboratory Co., Ltd., purity 2N) were further placed in the container and dry-mixed to obtain a mixture.

[0092] In a glove box, 240 g of the mixture was filled into a sealed tungsten container. After closing the lid of the sealed container, it was removed from the glove box and placed in an electric furnace equipped with a carbon heater. The electric furnace was then fully evacuated until the pressure inside was 0.1 PaG or less. Here, the sealed container has a structure in which the main body and the lid fit together, so the gap between the lid and the main body is narrower than in conventional containers, improving sealing performance.

[0093] While continuing to evacuate, the temperature inside the electric furnace was raised to 600°C. After reaching 600°C, nitrogen gas was introduced into the electric furnace and the pressure inside the electric furnace was adjusted to 0.85 MPaG. The temperature inside the electric furnace was then raised to 1950°C in a nitrogen gas atmosphere, and after reaching 1950°C, heat treatment was carried out for 8 hours. Heating was then terminated and the mixture was cooled to room temperature. After cooling to room temperature, red lumps were recovered from the container. The recovered lumps were crushed in a mortar and sieved to prepare core particles with a median diameter of 18 μm.

[0094] <Production of phosphor powder> 55.65 g of α-type silicon nitride (Si3N4, manufactured by Ube Industries, Ltd., SN-E10 grade), 48.78 g of aluminum nitride (AlN, manufactured by Tokuyama Corporation, E grade), 0.42 g of europium oxide (Eu2O3, manufactured by Shin-Etsu Chemical Co., Ltd.), and 24.00 g of the core particles prepared as described above were weighed and premixed in a container.

[0095] Next, in a glove box maintained in a nitrogen atmosphere with a moisture content of 1 mass ppm or less and an oxygen concentration of 50 mass ppm or less, 1.36 g of calcium nitride (Ca3N2, manufactured by Materion) and 109.80 g of strontium nitride (Sr3N2, manufactured by Kojundo Chemical Laboratory Co., Ltd., purity 2N) were further weighed and dry-mixed into the container. This yielded a mixed powder. Table 2 shows the relationship between the charged amounts of the core particles and the raw material powder (mass %), and Table 1 shows the breakdown of the charged amounts of each element in the raw material powder (molar ratio).

[0096] In a glove box, 240 g of the mixed powder was placed in a sealed tungsten container. After closing the lid of the sealed container, it was removed from the glove box and placed in an electric furnace equipped with a carbon heater. The electric furnace was then evacuated to a vacuum until the pressure inside was 0.1 PaG or less.

[0097] While continuing to evacuate, the temperature inside the electric furnace was raised to 600°C. After reaching 600°C, nitrogen gas was introduced into the electric furnace and the pressure inside the electric furnace was adjusted to 0.85 MPaG. The temperature inside the electric furnace was then raised to 1950°C in a nitrogen gas atmosphere, and after reaching 1950°C, heat treatment was carried out for 8 hours. After that, heating was stopped and the mixture was allowed to cool to room temperature. After cooling to room temperature, red lumps were recovered from the container. The recovered lumps were crushed and sieved to adjust the particle size, and a fired powder was obtained.

[0098] The resulting sintered powder was packed into a sealed tungsten container and quickly transferred to an electric furnace equipped with a carbon heater. The furnace was thoroughly evacuated until the pressure inside the furnace reached 0.1 PaG or less. Heating was started while continuing the evacuation. When the temperature reached 600°C, argon gas was introduced into the furnace and the pressure inside the furnace was adjusted to atmospheric pressure. After the introduction of argon gas began, the temperature continued to rise to 1350°C. After the temperature reached 1350°C, the heat treatment was carried out for 8 hours. Then, heating was stopped and the mixture was cooled to room temperature. After cooling to room temperature, the annealed powder was recovered from the container. The recovered powder was passed through a sieve to adjust the particle size. In this way, the annealed powder was obtained.

[0099] The obtained annealed powder was placed in 2.0 M hydrochloric acid at room temperature so that the slurry concentration was 25% by mass, and immersed at 70 to 80°C for 1 hour. This resulted in an acid treatment. After the acid treatment, the hydrochloric acid slurry was boiled for 1 hour while stirring. The boiled slurry was cooled to room temperature and filtered to separate the acid treatment liquid from the solid content, yielding an acid-treated product. The acid-treated product was then dried in a dryer set at a temperature in the range of 100 to 120°C for 12 hours, yielding an acid-treated powder.

[0100] The obtained acid-treated powder was added to an aqueous solution of sodium hexametaphosphate to prepare a dispersion, which was then stirred. The acid-treated powder in the dispersion was then allowed to settle, and the supernatant was removed. After removing the supernatant, the precipitate was collected by filtration and dried to obtain an acid-treated powder from which the fine particles had been removed. The preparation of the dispersion and the removal of the supernatant were repeated five times.

[0101] The resulting acid-treated powder was then loaded into an alumina crucible and quickly transferred to an electric furnace equipped with a carbon heater, where it was heated at a rate of 2.5°C / min under atmospheric pressure in an air atmosphere until the temperature reached 300°C. After the temperature reached 400°C, air heat treatment was carried out for 1 hour. After that, heating was stopped and the powder was cooled to room temperature, yielding an air-heat-treated powder. In this way, the phosphor powder of Example 1 was obtained.

[0102] The obtained phosphor sample was subjected to powder X-ray diffraction using CuKα radiation using an X-ray diffractometer (Ultima IV manufactured by Rigaku Corporation). The obtained X-ray diffraction pattern was identical to that of CaAlSiN3 crystals, confirming that the main crystalline phase had the same crystal structure as CaAlSiN3 crystals.

[0103] Example 2 A phosphor powder of Example 2 was obtained in the same manner as in Example 1, except that the raw material charging ratio was changed to the value shown in Table 1.

[0104] (Comparative Examples 1 to 3) The phosphor powders of Comparative Examples 1 to 3 were obtained in the same manner as in Example 1, except that a non-sealed tungsten container was used instead of a sealed tungsten container for firing and annealing, core particles were not added, atmospheric heat treatment was not performed, and the raw material charging ratio was changed to the value shown in Table 1. Here, the non-sealed container is a container having a structure in which a lid is simply placed on a main body.

[0105] <Elemental mapping> For the phosphor powder, an elemental mapping image of Sr was prepared using an electron beam microanalyzer (JEOL, JXA-8230) under the following conditions: acceleration voltage 15 kV, irradiation current 50 nA, beam diameter 0 μm, measurement time 30 msec, measurement area 160 μm × 160 μm, measurement interval 0.40 μm × 0.40 μm, and number of measurement points 400 × 400. Next, for each elemental mapping image, the area (S A ), the area of ​​the region (B) where the relative characteristic X-ray intensity is 0.8 or more (S B ) were measured by image analysis. A and S B From S A S against B The area ratio was calculated. The above procedure was repeated for 100 different fields of view, and the phosphor powder was A S against B If the sample contains one or more phosphor particles with an area ratio of 10.00% or less, it is determined to contain phosphor particles (S), and S A S against B If the phosphor powders contained no phosphor particles having an area ratio of 10.00% or less, they were determined to not contain phosphor particles (S). As a result, the phosphor powders of Examples 1 and 2 contained phosphor particles (S), while the phosphor powders of Comparative Examples 1 to 3 did not contain phosphor particles (S). Table 2 shows the S for any one visual field containing phosphor particles (S) for Examples 1 and 2. A S against B For Comparative Examples 1 to 3, the area ratio of S A S against B The area ratios of the above are shown. Next, for Examples 1 and 2, the proportion of the number of phosphor particles (S) was measured for any one visual field containing phosphor particles (S). The results are shown in Table 2.

[0106] <Composition> First, the phosphor powder was dissolved by pressure acid decomposition to prepare a sample solution. The resulting sample solution was then quantitatively analyzed using an ICP optical emission spectrometer (Shimadzu Corporation, ICPE-9000) to measure the molar ratios of Eu, Sr, Ca, Al, and Si contained in the phosphor powder. The results are shown in Table 1. Furthermore, 0.03 g of the phosphor powder was weighed out, and the oxygen and nitrogen contents were measured using an oxygen / nitrogen analyzer to determine the molar ratio of N and O. The results are shown in Table 1.

[0107] <Particle size> The particle size distribution of the phosphor powder was measured using a particle size distribution analyzer (Microtrac MT3300EX II, manufactured by Microtrac-Bell) by the laser diffraction scattering method in accordance with JIS R1629:1997. Specifically, approximately 0.1 g of phosphor powder was added to 100 mL of ion-exchanged water, and the mixture was dispersed for 3 minutes using an ultrasonic homogenizer (Nippon Seiki Seisakusho, Ultrasonic Homogenizer US-150E, tip size φ20 mm, amplitude 100%, oscillation frequency 19.5 kHz, amplitude approximately 31 μm). After that, measurements were made using the particle size distribution analyzer. From the obtained particle size distribution, the median diameter D of the phosphor powder was calculated. 50 , the particle diameter D at which the cumulative value reaches 10% 10 , the particle diameter D at which the cumulative value reaches 90% 90 and (D 90 -D 10 ) / D 50 The results are shown in Table 2.

[0108] <Fluorescence spectrum> The fluorescence spectrum of the phosphor powder was measured using a spectrofluorometer (Hitachi High-Technologies Corporation, F-7000) corrected with rhodamine B and a secondary standard light source. A solid sample holder attached to the spectrometer was used for the measurement, and the fluorescence spectrum was measured for light with an excitation wavelength of 455 nm.

[0109] <Internal quantum efficiency, external quantum efficiency> The emission intensity of the phosphor powder was determined from the obtained fluorescence spectrum data, and the number of reflected excitation light photons (Qref) and the number of fluorescence photons (Qem) were calculated. The number of reflected excitation light photons was calculated in the wavelength range of 450 to 465 nm, and the number of fluorescence photons was calculated in the range of 465 to 800 nm. Using the same device, a standard reflector with a reflectivity of 99% (Spectralon®, manufactured by Labsphere) was attached to the opening of the integrating sphere to measure the spectrum of excitation light with a wavelength of 455 nm. The number of excitation light photons (Qex) was calculated from the spectrum in the wavelength range of 450 to 465 nm. From the above calculation results, the internal quantum efficiency and external quantum efficiency of the phosphor powder for light of 455 nm were calculated based on the following formulas. The results are shown in Table 2. Internal quantum efficiency = (Qem / (Qex-Qref)) x 100 External quantum efficiency = (Qem / Qex) x 100

[0110] <Total luminous flux, chromaticity y> The phosphor powder and silicone resin (DuPont Toray Specialty Materials, OE6656) were mixed in a mixer (Thinky Corporation, ARE-310) to obtain a composite, with the phosphor powder content at 10% by mass. An LED with a peak wavelength of 455 nm was then placed at the bottom of the recessed package, and the LED was wire-bonded to the electrode on the substrate of the recessed package. The composite was then poured into the recess of the recessed package and cured at 150°C to obtain a light-emitting device. The total luminous flux (lm) and chromaticity (y) of the light-emitting device were then measured using a total luminous flux meter (Otsuka Electronics, HM Series). The results are shown in Table 2.

[0111] The raw material ratios are shown in Table 1. The raw material ratios are molar ratios when Al is taken as 1.000. The composition of the phosphor powder is shown in Table 1. The composition is expressed as a molar ratio when Al is taken as 1.000.

[0112] [Table 1]

[0113] [Table 2]

[0114] 1. Phosphor powder 30 Encapsulating material 40 Complex 100 Light-emitting device 120 Light-emitting element 130 Heatsink 140 cases 150 First lead frame 160 Second lead frame 170 Bonding Wire 172 Bonding Wire

Claims

1. A phosphor powder comprising SCASN phosphor particles, The SCASN phosphor particles are determined by measuring an elemental mapping image of Sr using an electron probe microanalyzer (EPMA) under the following measurement conditions. The area of ​​a region (A) where the relative characteristic X-ray intensity is 0.5 or more when the maximum value of the characteristic X-ray intensity is 1.0 is defined as S. Ａ The area of ​​the region (B) where the relative characteristic X-ray intensity is 0.8 or more is defined as S Ｂ When this is done, S Ａ S against Ｂ The phosphor powder comprises phosphor particles (S) having an area ratio of 10.00% or less. (Measurement conditions) Acceleration voltage: 15 kV Irradiation current: 50 nA Beam diameter: 0 μm Measurement time: 30msec Measurement area: 160μm x 160μm Measurement interval: 0.40μm x 0.40μm Number of measurement points: 400 x 400

2. The phosphor powder according to claim 1 , wherein the number ratio of the phosphor particles (S) in the SCASN phosphor particles is 0.5% or more and 50.0% or less.

3. The phosphor powder according to claim 1 or 2, wherein the SCASN phosphor particles include columnar phosphor particles.

4. General formula, Eu ａ Sr ｂ Ca ｃ AlSi ｅ N ｆ O ｇ 3. The phosphor powder according to claim 1, comprising phosphor particles represented by the formula: 0<a<1.000, 0<b<1.000, 0<c<1.000, 0.700<a+b+c<1.300, 0.700<e<1.300, 0<f<3.000, 0<g<3.000, 2.500<f+g<3.

500.

5. The phosphor powder according to claim 4, wherein a<0.

300.

6. 5. The phosphor powder according to claim 4, wherein b>0.

500.

7. 5. The phosphor powder according to claim 4, wherein the molar ratio of b / (b+c) of the phosphor particles is 0.960 or more and 0.990 or less.

8. The volume-based median diameter D of the phosphor powder measured by the laser diffraction scattering method ５０ The phosphor powder according to claim 1 or 2, wherein the particle size is 15.0 μm or more and 35.0 μm or less.

9. In the volume frequency particle size distribution of the phosphor powder by the laser diffraction scattering method, the particle diameter D at which the cumulative value becomes 10% is １０ The phosphor powder according to claim 1 or 2, wherein the particle size is 10.0 μm or more and 20.0 μm or less.

10. In the volume frequency particle size distribution of the phosphor powder by the laser diffraction scattering method, the particle diameter D at which the cumulative value reaches 90% ９０ The phosphor powder according to claim 1 or 2, wherein the particle size is 30.0 μm or more and 60.0 μm or less.

11. In the volume frequency particle size distribution of the phosphor powder by the laser diffraction scattering method, the particle diameter D at which the cumulative value becomes 10% is １０ , 90% particle diameter D ９０ , median diameter D ５０ Regarding (D ９０ -D １０ ) / D ５０ 3. The phosphor powder according to claim 1, wherein the value of is 0.50 or more and 1.50 or less.

12. 3. The phosphor powder according to claim 1, wherein the total luminous flux and chromaticity y are measured by the following method, and the value of total luminous flux / chromaticity y is 370 lm or more. (method) The phosphor powder and silicone resin are mixed in a mixer so that the phosphor powder is 10% by mass, resulting in a composite. An LED with a peak wavelength of 455 nm is then placed at the bottom of the recessed package, and the LED is wire-bonded to an electrode on the substrate of the recessed package. The composite is then poured into the recess of the recessed package and cured at 150°C, resulting in a light-emitting device. The total luminous flux (lm) and chromaticity y of the light-emitting device are then measured using a total luminous flux meter.

13. The phosphor powder according to claim 12 , wherein the chromaticity y is 0.100 or more and 0.400 or less.

14. A composite comprising the phosphor powder according to claim 1 or 2 and a sealant that seals the phosphor powder.

15. a light emitting element that emits excitation light; The composite of claim 14 that converts the wavelength of the excitation light; A light emitting device comprising:

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