Phosphor powder, composite, and light-emitting device

Abstract

To provide a phosphor powder having enhanced balance of properties among applicability of the resulting composite for a compact light-emitting device, luminous intensity, and ability to block excitation light.SOLUTION: A phosphor powder comprises SCASN phosphor particles, the phosphor powder having a volume-based median diameter D50 of 0.1 μm or more and 5.0 μm or less as measured by a laser diffraction scattering method, the phosphor powder exhibiting a fluorescence spectrum peak wavelength of 590.0 nm or more and 630.0 nm or less as measured by a spectrophotometer when irradiated with light having a wavelength of 455 nm, and the phosphor powder having an absorption rate of 80.0% or more when irradiated with light having a wavelength of 455 nm.SELECTED DRAWING: None

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. Known examples of red phosphors include 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 in which the composite obtained has improved applicability to small light-emitting devices and an improved performance balance between luminance and excitation light-blocking properties; a composite in which the composite has improved applicability to small light-emitting devices and an improved performance balance between luminance and excitation light-blocking properties; and a light-emitting device in which the performance balance between luminance and excitation light-blocking properties is improved. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, it has been discovered that a phosphor powder containing SCASN phosphor particles has a volume-based median diameter D of the phosphor powder measured by a laser diffraction scattering method. 50 The inventors have found that a phosphor powder having a particle size of 0.1 μm or more and 5.0 μm or less, a peak wavelength of a fluorescence spectrum measured by a spectrophotometer when the phosphor powder is irradiated with light of a wavelength of 455 nm, of 590.0 nm or more and 630.0 nm or less, and an absorptance of 80.0% or more when the phosphor powder is irradiated with light of a wavelength of 455 nm, can improve the applicability to small light-emitting devices and the performance balance between brightness and excitation light-blocking properties, 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 volume-based median diameter D of the phosphor powder measured by the laser diffraction scattering method 50 is 0.1 μm or more and 5.0 μm or less, the peak wavelength of the fluorescence spectrum measured by a spectrophotometer when the phosphor powder is irradiated with light having a wavelength of 455 nm is 590.0 nm or more and 630.0 nm or less; The phosphor powder has an absorptance of 80.0% or more when irradiated with light having a wavelength of 455 nm. [2] The SCASN phosphor particles have the general formula Eu a Sr b Ca c AlSi d N eO f The phosphor powder according to [1], comprising phosphor particles represented by f , where 0 < a < 1.000, 0 ≤ b < 1.000, 0 ≤ c < 1.000, 0.700 < a + b + c < 1.300, 0.700 < d < 1.300, 0 ≤ e ≤ 3.000, 0 ≤ f ≤ 3.000, and 2.500 ≤ e + f ≤ 3.500. [3] The phosphor powder according to [2], where 0 < a < 0.300. [4] The phosphor powder according to [2] or [3], where 0.700 < b < 1.000. <00> [5] The phosphor powder according to any one of [2] to [4], where the molar ratio of b / (b + c) of the phosphor particles is 0.800 or more and 0.990 or less. [6] 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 is 10% 10 is 0.01 μm or more and 3.0 μm or less. The phosphor powder according to any one of [1] to [5]. [7] 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 is 90% 90 is 1.0 μm or more and 10.0 μm or less. The phosphor powder according to any one of [1] to [6]. [8]<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 is 10% 10 , the particle diameter D at which the cumulative value is 90% 90 , and the median diameter D 50 For these, (D 90 -D 10 ) / D 50 The value of is 3.00 or less. The phosphor powder according to any one of [1] to [7]. [9] The phosphor powder according to any one of [1] to [8], where the full width at half maximum of the peak of the fluorescence spectrum is 85.0 nm or less.

[10] The phosphor powder according to any one of [1] to [9], which has a diffuse reflectance of 80.0% or more at a wavelength of 700 nm measured by an ultraviolet-visible spectrophotometer.

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

[10] , which has an external quantum efficiency QE of 47.5% or more when formed into a sheet by the following method 1. (Method 1) The phosphor powder and silicone resin are mixed in a mixer so that the phosphor powder is 40% by mass, resulting in a composite. The composite is then coated and cured at 150°C to obtain a 20 μm-thick sheet. Light with a wavelength of 455 nm is then irradiated onto the sheet, and the emission spectrum of the light passing through the sheet is measured using a total luminous flux meter. The number of fluorescent photons in the wavelength range of 493 to 800 nm in the emission spectrum is then defined as Qem. The same device is then used to measure the emission spectrum of the 455 nm light used in the total luminous flux measurement. The number of excitation light photons in the wavelength range of 401 to 492 nm in the emission spectrum of the 455 nm light is then defined as Qex. The value (Qem / Qex) × 100 is then calculated, which is the external quantum efficiency QE of the sheet during molding.

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

[11] , which has an excitation light transmittance T of 11.0% or less, as measured by the following method 2. (Method 2) The phosphor powder and silicone resin are mixed in a mixer so that the phosphor powder is 40% by mass, to obtain a composite. The composite is then coated and cured at 150°C to obtain a sheet with a thickness of 20 μm. The sheet is then irradiated with light having a wavelength of 455 nm, and the emission spectrum of the light passing through the sheet is measured using a total luminous flux meter. In the emission spectrum, the number of photons of the transmitted excitation light in the wavelength range of 401 to 492 nm is defined as Qt. The same device is then used to measure the emission spectrum of the 455 nm light used in the total luminous flux measurement. In the emission spectrum of the 455 nm light, the number of photons of the excitation light in the wavelength range of 401 to 492 nm is defined as Qex. The value of (Qt / Qex) × 100 is then calculated, and this is defined as the excitation light transmittance T.

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

[12] , which can be used in a micro LED display.

[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 in which the composite obtained has improved applicability to small light-emitting devices and has an improved performance balance between luminance and excitation light-blocking properties, a composite in which the composite has improved applicability to small light-emitting devices and has an improved performance balance between luminance and excitation light-blocking properties, and a light-emitting device in which the performance balance between luminance and excitation light-blocking properties is improved. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail.

[0011] In this embodiment, "A to B" indicating a numerical range means A or more and B or less unless otherwise specified.

[0012] <Phosphor powder> The phosphor powder of this embodiment contains SCASN phosphor particles. The SCASN phosphor particles of this embodiment are composed of (Si,Al)-N4 regular tetrahedrons bonded together, and some of the Ca atoms located in the gaps of the skeleton are replaced with Sr atoms to form a solid solution. 2+ A part of Eu acts as a luminescence center 2+ These are phosphor particles in which activator elements such as fluorine atoms are substituted.

[0013] The phosphor powder of this embodiment has a volume-based median diameter D 50is 0.1 μm or more and 5.0 μm or less, the peak wavelength of the fluorescence spectrum measured by a spectrophotometer when the phosphor powder is irradiated with light of a wavelength of 455 nm is 590.0 nm or more and 630.0 nm or less, and the absorptance when the phosphor powder is irradiated with light of a wavelength of 455 nm is 80.0% or more.

[0014] According to the study by the present inventors, in a phosphor powder containing SCASN phosphor particles, the median diameter D 50 It was revealed that the smaller the value, the more the applicability of the resulting composite to a small light-emitting device and the more the excitation light-shielding property of the resulting composite improves, but the brightness of the resulting composite tends to decrease.

[0015] As a result of further investigations, the inventors have found that in phosphor powders containing SCASN phosphor particles, there is a correlation between the absorptivity when the phosphor powder is irradiated with light having a wavelength of 455 nm and the brightness of the resulting composite.

[0016] As a result of further investigation based on the above findings, the inventors have found that the volume-based median diameter D 50 The inventors have found that by setting the particle size to 0.1 μm or more and 5.0 μm or less, setting the peak wavelength of the fluorescence spectrum measured by a spectrophotometer when the phosphor powder is irradiated with light of a wavelength of 455 nm to 590.0 nm or more and 630.0 nm or less, and setting the absorptance when the phosphor powder is irradiated with light of a wavelength of 455 nm to 80.0% or more, the applicability of the obtained composite to small light-emitting devices and the performance balance of brightness and excitation light-blocking ability can be improved, thereby completing the present invention.

[0017] 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 obtained composite, is 0.1 μm or more, preferably 0.5 μm or more, more preferably 0.8 μm or more, even more preferably 1.0 μm or more, even more preferably 1.2 μm or more, even more preferably 1.5 μm or more, even more preferably 1.8 μm or more, and even more preferably 2.0 μm or more. The volume-based median diameter D of the phosphor powder of this embodiment measured by the laser diffraction scattering method is 50 is 5.0 μm or less, preferably 4.5 μm or less, more preferably 4.2 μm or less, even more preferably 3.9 μm or less, even more preferably 3.7 μm or less, even more preferably 3.0 μm or less, even more preferably 2.5 μm or less, and even more preferably 2.0 μm or less, from the viewpoint of further improving the applicability of the obtained composite to small light-emitting devices and the excitation light-blocking properties.

[0018] The volume-based median diameter D of the phosphor powder of this embodiment measured by the laser diffraction scattering method 50 is 0.1 μm or more and 5.0 μm or less, preferably 0.5 μm or more and 4.5 μm or less, more preferably 0.8 μm or more and 4.2 μm or less, even more preferably 1.0 μm or more and 3.7 μm or less, and even more preferably 1.2 μm or more and 3.0 μm or less, from the viewpoint of further improving the applicability of the obtained composite to small light-emitting devices and the performance balance between brightness and excitation light-blocking property. The volume-based median diameter D of the phosphor powder of this embodiment measured by the laser diffraction scattering method is 50 is from 0.1 μm to 5.0 μm, preferably from 0.3 μm to 4.0 μm, more preferably from 0.5 μm to 3.0 μm, even more preferably from 0.8 μm to 2.5 μm, even more preferably from 1.0 μm to 2.0 μm, and even more preferably from 1.2 μm to 1.7 μm, from the viewpoint of further improving the applicability of the obtained composite to small light-emitting devices and the performance balance between brightness and excitation light-blocking properties, while further improving the applicability of the obtained composite to small light-emitting devices and the excitation light-blocking properties. The volume-based median diameter D of the phosphor powder of this embodiment measured by the laser diffraction scattering method is 50 is from 0.1 μm to 5.0 μm, preferably from 0.5 μm to 4.5 μm, more preferably from 1.0 μm to 4.2 μm, even more preferably from 1.5 μm to 3.7 μm, and even more preferably from 2.0 μm to 3.0 μm, from the viewpoint of further improving the applicability of the obtained composite to a small light-emitting device and the performance balance between brightness and excitation light-blocking property, while further improving the brightness of the obtained composite.

[0019] In this embodiment, the median diameter D 50 can be determined, for example, by the following method. First, about 30 mg of phosphor powder is added to 100 mL of 0.2% sodium hexametaphosphate aqueous solution, and the mixture is dispersed for 3 minutes using an Ultrasonic Homogenizer US-150E (manufactured by Nippon Seiki Seisakusho, tip size φ20 mm, amplitude 100%, oscillation frequency 19.5 kHz, amplitude approximately 31 μm). After that, the particle size distribution is measured using a laser diffraction scattering particle size distribution measuring device. Next, the median diameter D of the phosphor powder is calculated from the obtained particle size distribution. 50 Ask for.

[0020] When the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm, the peak wavelength of the fluorescence spectrum measured by a spectrophotometer is 590.0 nm or more and 630.0 nm or less, preferably 600.0 nm or more and 629.0 nm or less, more preferably 610.0 nm or more and 628.0 nm or less, even more preferably 615.0 nm or more and 627.5 nm or less, and even more preferably 620.0 nm or more and 627.0 nm or less, from the viewpoint of further improving the performance balance of color gamut and brightness.

[0021] In this embodiment, the peak wavelength of the phosphor powder can be determined, for example, by the following method. First, the phosphor powder is filled into a concave cell so that the surface is smooth. The concave cell is then attached to the opening of an integrating sphere. Monochromatic light with a wavelength of 455 nm, split from a light source (Xe lamp), is then introduced into the integrating sphere using an optical fiber as excitation light. The monochromatic light is then irradiated onto the phosphor powder, and the fluorescence spectrum of the phosphor powder is measured using a spectrophotometer. The peak wavelength of the phosphor powder is then determined from the obtained fluorescence spectrum.

[0022] The absorptance when the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm is 80.0% or more, preferably 80.5% or more, more preferably 81.0% or more, even more preferably 83.0% or more, and even more preferably 85.0% or more, from the viewpoint of further improving the brightness of the resulting composite. The upper limit of the absorptance when the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm is not particularly limited, but may be, for example, 99.0% or less, 95.0% or less, or 90.0% or less.

[0023] The absorptance when the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm is preferably 80.0% or more and 99.0% or less, more preferably 80.5% or more and 95.0% or less, and even more preferably 81.0% or more and 90.0% or less, from the viewpoint of further improving the applicability of the resulting composite to small light-emitting devices and the performance balance between brightness and excitation light blocking properties. Furthermore, the absorptance when the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm is preferably 80.0% or more and 99.0% or less, more preferably 80.5% or more and 95.0% or less, even more preferably 81.0% or more and 90.0% or less, and even more preferably 81.0% or more and 86.0% or less, from the viewpoint of further improving the applicability of the obtained composite to small light-emitting devices and the performance balance between brightness and excitation light-blocking properties. Furthermore, the absorptance when the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm is preferably 80.0% or more and 99.0% or less, more preferably 81.0% or more and 95.0% or less, even more preferably 83.0% or more and 92.0% or less, even more preferably 85.0% or more and 91.0% or less, and even more preferably 86.0% or more and 90.0% or less, from the viewpoint of further improving the applicability of the resulting composite to small light-emitting devices and the performance balance between brightness and excitation light blocking properties while further improving the brightness of the resulting composite.

[0024] In this embodiment, the absorptance of the phosphor powder can be determined, for example, by the following method. The emission intensity of the phosphor powder is determined from the fluorescence spectrum data obtained using the same method as for measuring the peak wavelength described above, 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. The number of excitation light photons (Qex) is then calculated from the spectrum in the wavelength range of 450 to 465 nm. Next, the absorption rate when the phosphor powder is irradiated with light with a wavelength of 455 nm is calculated from the above calculation results using the following formula. Absorption rate = ((Qex-Qref) / Qex) x 100

[0025] 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 Eu-containing raw material and a larger amount of Sr-containing raw material, etc. Regarding the manufacturing procedure and manufacturing conditions, it is preferable to extend the grinding time in the second grinding step, etc. Details of these will be described later.

[0026] <Crystal structure, elemental composition, etc.> The crystalline phase of the phosphor powder can be confirmed by powder X-ray diffraction. A single crystalline phase is preferable, but other phases may be present as long as they do not significantly affect the phosphor properties. The presence or absence of other phases can be determined, for example, by the presence or absence of peaks other than those due to the target crystalline phase by powder X-ray diffraction.

[0027] The SCASN phosphor particles in the phosphor powder of this embodiment are preferably represented by the general formula Eu a Sr b Ca c AlSi d N e O fIt 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 < d < 1.300, 0 ≤ e ≤ 3.000, 0 ≤ f ≤ 3.000, and 2.500 ≤ e + f ≤ 3.500.

[0028] In the above general formula, a is preferably 0 < a < 0.300, more preferably 0.001 < a < 0.200, still more preferably 0.010 < a < 0.150, still more preferably 0.020 < a < 0.100, still more preferably 0.030 < a < 0.080, and still more preferably 0.035 < a < 0.060.

[0029] In the above general formula, b is preferably 0.700 < b < 1.000, more preferably 0.800 < b < 0.990, still more preferably 0.850 < b < 0.970, still more preferably 0.860 < b < 0.960, and still more preferably 0.870 < b < 0.950.

[0030] As another index from the viewpoint of "a large amount of Sr", the molar ratio of b / (b + c) is preferably 0.800 or more and 0.990 or less, more preferably 0.850 or more and 0.990 or less, still more preferably 0.900 or more and 0.990 or less, still more preferably 0.910 or more and 0.985 or less, and still more preferably 0.915 or more and 0.985 or less.

[0031] In the above general formula, c is preferably 0 < c < 1.000, more preferably 0.001 < c < 0.500, still more preferably 0.005 < c < 0.300, still more preferably 0.010 < c < 0.200, and still more preferably 0.015 < c < 0.100.

[0032] In the above general formula, d is preferably 0.800 < d < 1.200, more preferably 0.900 < d < 1.100, still more preferably 0.950 < d < 1.080, still more preferably 0.980 < d < 1.060, and still more preferably 1.000 < d < 1.050.

[0033] In the above general formula, e is preferably 0 < e < 3.000, more preferably 1.000 < e < 3.000, still more preferably 2.000 < e < 3.000, still more preferably 2.100 < e < 2.900, still more preferably 2.200 < e < 2.850, still more preferably 2.300 < e < 2.800.

[0034] In the above general formula, f is preferably 0 < f < 3.000, more preferably 0.010 < f < 2.000, still more preferably 0.050 < f < 1.500, still more preferably 0.100 < f < 1.000, still more preferably 0.200 < f < 0.900, still more preferably 0.300 < f < 0.800.

[0035] In the above general formula, a + b + c is preferably 0.800 < a + b + c < 1.200, more preferably 0.900 < a + b + c < 1.100, still more preferably 0.950 < a + b + c < 1.050, still more preferably 0.980 < a + b + c < 1.030.

[0036] In the above general formula, e + f is preferably 2.500 < e + f < 3.500, more preferably 2.700 < e + f < 3.400, still more preferably 2.900 < e + f < 3.300, still more preferably 3.000 < e + f < 3.250, still more preferably 3.020 < e + f < 3.230.

[0037] 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 subjecting the obtained sample solution to quantitative analysis of the elements using an ICP emission spectroscopic analyzer. In this embodiment, among the molar ratios of the respective elements contained in the phosphor powder, the molar ratios of N and O can be obtained, for example, by weighing 0.03 g of the phosphor powder and measuring the contents of oxygen and nitrogen using an oxygen / nitrogen analyzer.

[0038] <Particle size> 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 is preferably 0.01 μm or more and 3.0 μm or less, more preferably 0.1 μm or more and 2.5 μm or less, even more preferably 0.3 μm or more and 2.0 μm or less, and even more preferably 0.5 μm or more and 1.5 μm or less, from the viewpoint of further improving the applicability of the obtained composite to small light-emitting devices and the performance balance between brightness and excitation light-blocking property. 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 10 is preferably 0.01 μm or more and 3.0 μm or less, more preferably 0.1 μm or more and 2.0 μm or less, even more preferably 0.3 μm or more and 1.5 μm or less, even more preferably 0.5 μm or more and 1.0 μm or less, and even more preferably 0.5 μm or more and 0.8 μm or less, from the viewpoint of further improving the applicability of the obtained composite to small light-emitting devices and the performance balance between brightness and excitation light-blocking properties while further improving the applicability of the obtained composite to small light-emitting devices and the excitation light-blocking properties. 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 10 is preferably 0.01 μm or more and 3.0 μm or less, more preferably 0.1 μm or more and 2.5 μm or less, even more preferably 0.5 μm or more and 2.0 μm or less, and even more preferably 1.0 μm or more and 1.5 μm or less, from the viewpoint of further improving the applicability of the obtained composite to a small light-emitting device and the performance balance between brightness and excitation light-blocking property, while further improving the brightness of the obtained composite.

[0039] 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 is preferably 1.0 μm or more and 10.0 μm or less, more preferably 1.5 μm or more and 8.0 μm or less, even more preferably 2.0 μm or more and 6.0 μm or less, and even more preferably 2.3 μm or more and 5.0 μm or less, from the viewpoint of further improving the applicability of the obtained composite to small light-emitting devices and the performance balance between brightness and excitation light-blocking property. 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 90 is preferably 1.0 μm or more and 10.0 μm or less, more preferably 1.5 μm or more and 7.0 μm or less, even more preferably 2.0 μm or more and 5.0 μm or less, even more preferably 2.3 μm or more and 4.0 μm or less, and even more preferably 2.4 μm or more and 3.0 μm or less, from the viewpoint of further improving the applicability of the obtained composite to small light-emitting devices and the performance balance between brightness and excitation light-blocking properties while further improving the applicability of the obtained composite to small light-emitting devices and the excitation light-blocking properties. 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 90 is preferably 1.0 μm or more and 10.0 μm or less, more preferably 2.0 μm or more and 8.0 μm or less, even more preferably 3.0 μm or more and 6.0 μm or less, even more preferably 3.5 μm or more and 5.5 μm or less, and even more preferably 4.0 μm or more and 5.0 μm or less, from the viewpoint of further improving the applicability of the obtained composite to small light-emitting devices and the performance balance between brightness and excitation light-blocking property, while further improving the brightness of the obtained composite.

[0040] In the volume frequency particle size distribution of the phosphor powder of this embodiment by the laser diffraction scattering method, (D 90 -D 10 ) / D 50 From the viewpoint of further improving the applicability of the obtained composite to small light-emitting devices and the performance balance between brightness and excitation light-blocking property, the value of is preferably 3.00 or less, more preferably 2.50 or less, even more preferably 2.00 or less, even more preferably 1.80 or less, even more preferably 1.70 or less, and even more preferably 1.60 or less. In the volume frequency particle size distribution of the phosphor powder of this embodiment by the laser diffraction scattering method, (D 90 -D 10 ) / D 50The lower limit of the value is not particularly limited, but may be, for example, 0.50 or more, 0.80 or more, 1.00 or more, 1.10 or more, 1.20 or more, or 1.25 or more. In addition, in the volume frequency particle size distribution of the phosphor powder of this embodiment by the laser diffraction scattering method, (D 90 -D 10 ) / D 50 From the viewpoint of applicability of the obtained composite to a small light-emitting device and further improving the performance balance between brightness and excitation light-blocking property, the value of is preferably 0.50 or more and 3.00 or less, more preferably 0.80 or more and 2.50 or less, even more preferably 1.00 or more and 2.00 or less, even more preferably 1.10 or more and 1.80 or less, even more preferably 1.20 or more and 1.70 or less, and even more preferably 1.25 or more and 1.60 or less.

[0041] In this embodiment, the particle diameter D at which the cumulative value in the volume frequency particle size distribution of the phosphor powder by the laser diffraction scattering method becomes 10% 10 , the particle diameter D at which the cumulative value reaches 90% 90 and (D 90 -D 10 ) / D 50 The value of is, for example, the aforementioned median diameter D 50 It can be determined from the particle size distribution obtained in the same manner as in the method for measuring the particle size.

[0042] <Light-emitting characteristics> When the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm, the half-width of the peak of the fluorescence spectrum measured by a spectrophotometer is preferably 85.0 nm or less, more preferably 83.0 nm or less, even more preferably 82.0 nm or less, and even more preferably 81.0 nm or less, from the viewpoint of further improving the light-emitting characteristics. When the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm, the lower limit of the half-width of the peak of the fluorescence spectrum measured by a spectrophotometer is not particularly limited, but may be, for example, 70.0 nm or more, or 75.0 nm or more. Furthermore, when the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm, the half-width of the peak of the fluorescence spectrum measured by a spectrophotometer is preferably 70.0 nm or more and 85.0 nm or less, more preferably 70.0 nm or more and 83.0 nm or less, even more preferably 75.0 nm or more and 82.0 nm or less, and even more preferably 75.0 nm or more and 81.0 nm or less, from the viewpoint of further improving the light-emitting characteristics.

[0043] In this embodiment, the half-value width of the peak of the phosphor powder can be determined from a fluorescence spectrum obtained in the same manner as the above-mentioned method for measuring the peak wavelength.

[0044] The diffuse reflectance at a wavelength of 700 nm of the phosphor powder of this embodiment measured by an ultraviolet-visible spectrophotometer is preferably 80.0% or more, more preferably 82.0% or more, even more preferably 84.0% or more, and even more preferably 85.0% or more, from the viewpoint of further improving the light-emitting characteristics. The upper limit of the diffuse reflectance of the phosphor powder of this embodiment at a wavelength of 700 nm measured by an ultraviolet-visible spectrophotometer is not particularly limited, but may be, for example, 99.0% or less, or 95.0% or less. Furthermore, from the viewpoint of further improving the light-emitting characteristics, the diffuse reflectance at a wavelength of 700 nm of the phosphor powder of this embodiment measured by an ultraviolet-visible spectrophotometer is preferably 80.0% or more and 99.0% or less, more preferably 82.0% or more and 99.0% or less, even more preferably 84.0% or more and 95.0% or less, and even more preferably 85.0% or more and 95.0% or less.

[0045] In this embodiment, the diffuse reflectance of the phosphor powder can be determined, for example, by the following method. First, a UV-visible spectrophotometer equipped with an integrating sphere is used to perform baseline correction using a standard reflector, and then a solid sample holder filled with phosphor powder is set in place. The diffuse reflectance is measured in the wavelength range of 450 to 800 nm to obtain a diffuse reflectance spectrum. The diffuse reflectance at a wavelength of 700 nm is then calculated from the resulting diffuse reflectance spectrum.

[0046] When the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm, the relative fluorescence intensity of the fluorescence spectrum measured by a spectrophotometer is, from the viewpoint of further improving the light-emitting characteristics, preferably 120.0% or more, more preferably 140.0% or more, even more preferably 150.0% or more, even more preferably 155.0% or more, and even more preferably 156.0% or more, when the fluorescence intensity of the standard sample YAG:Ce is taken as 100%. When the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm, the upper limit of the relative fluorescence intensity of the fluorescence spectrum measured by a spectrophotometer is not particularly limited, but may be, for example, 250.0% or less, or 200.0% or less. Furthermore, from the viewpoint of further improving the light-emitting characteristics, when the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm, the relative fluorescence intensity of the fluorescence spectrum measured by a spectrophotometer is preferably 120.0% or more and 250.0% or less, more preferably 140.0% or more and 250.0% or less, even more preferably 150.0% or more and 250.0% or less, even more preferably 155.0% or more and 200.0% or less, and even more preferably 156.0% or more and 200.0% or less, when the fluorescence intensity of the standard sample YAG:Ce is taken as 100%.

[0047] In this embodiment, the relative fluorescence intensity of the phosphor powder can be measured, for example, by the following method. First, using a spectrofluorometer calibrated with rhodamine B and a secondary standard light source, and using the solid sample holder attached to the spectrometer, measure the fluorescence spectrum of the phosphor powder at an excitation wavelength of 455 nm. Next, the peak height of the emission spectrum obtained by irradiating YAG:Ce with monochromatic light at 455 nm is set to 100%, and the peak intensity of the obtained fluorescence spectrum is expressed as the relative peak intensity (%) to calculate the relative fluorescence intensity.

[0048] <External quantum efficiency QE> The external quantum efficiency QE of the phosphor powder of this embodiment when molded into a sheet is preferably 47.5% or more, more preferably 48.0% or more, even more preferably 49.5% or more, and even more preferably 50.5% or more, from the viewpoint of further improving the brightness of the resulting composite. The upper limit of the external quantum efficiency QE of the phosphor powder of this embodiment when formed into a sheet is not particularly limited, but may be, for example, 70.0% or less, or 60.0% or less. Furthermore, from the viewpoint of further improving the brightness of the resulting composite, the external quantum efficiency QE of the phosphor powder of this embodiment when molded into a sheet is preferably 47.5% or more and 70.0% or less, more preferably 48.0% or more and 70.0% or less, even more preferably 49.5% or more and 60.0% or less, and even more preferably 50.5% or more and 60.0% or less.

[0049] In this embodiment, the external quantum efficiency QE when the phosphor powder is molded into a sheet can be determined, for example, by the following method. First, the phosphor powder and silicone resin are mixed in a mixer so that the phosphor powder is 40% by mass, resulting in a composite. The composite is then coated and cured at 150°C to obtain a 20 μm-thick sheet. The sheet is then irradiated with light at a wavelength of 455 nm, and the emission spectrum of the light passing through the sheet is measured using a total luminous flux meter. The number of fluorescent photons in the wavelength range of 493 to 800 nm in the emission spectrum is defined as Qem. The same device is then used to measure the emission spectrum of the 455 nm light used in the total luminous flux measurement. The number of excitation light photons in the wavelength range of 401 to 492 nm in the emission spectrum of the 455 nm light is then defined as Qex. The value (Qem / Qex) × 100 is then calculated, which is the external quantum efficiency (QE) of the sheet.

[0050] <Excitation light transmittance T> The excitation light transmittance T of the phosphor powder of this embodiment is preferably 11.0% or less, more preferably 10.0% or less, even more preferably 9.5% or less, even more preferably 9.0% or less, and even more preferably 8.5% or less, from the viewpoint of further improving the excitation light blocking properties of the resulting composite. The lower limit of the excitation light transmittance T of the phosphor powder of this embodiment is not particularly limited, but may be, for example, 1.0% or more, or 3.0% or more. Furthermore, from the viewpoint of further improving the excitation light blocking properties of the resulting composite, the excitation light transmittance T of the phosphor powder of this embodiment is preferably 1.0% or more and 11.0% or less, more preferably 1.0% or more and 10.0% or less, even more preferably 3.0% or more and 9.5% or less, even more preferably 3.0% or more and 9.0% or less, and even more preferably 3.0% or more and 8.5% or less.

[0051] In this embodiment, the excitation light transmittance T of the phosphor powder can be determined, for example, by the following method. First, the phosphor powder and silicone resin are mixed in a mixer so that the phosphor powder is 40% by mass, resulting in a composite. The composite is then coated and cured at 150°C to obtain a 20 μm-thick sheet. The sheet is then irradiated with light at a wavelength of 455 nm, and the emission spectrum of the light passing through the sheet is measured using a total luminous flux meter. The number of photons of the transmitted excitation light in the wavelength range of 401 to 492 nm in the emission spectrum is defined as Qt. The same device is then used to measure the emission spectrum of the 455 nm light used in the total luminous flux measurement. The number of photons of the excitation light in the wavelength range of 401 to 492 nm in the emission spectrum of the 455 nm light is then defined as Qex. The value of (Qt / Qex) × 100 is then calculated, which is the excitation light transmittance, T.

[0052] <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, the 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 mass; A first classification step in which the lumps are crushed and classified to obtain fired powder; a first grinding step of grinding the fired powder; an annealing step of annealing the pulverized sintered powder to obtain annealed powder; a second grinding step of grinding the annealed powder; an elutriation step of removing fine particles from the pulverized annealed powder by elutriation to obtain elutriated powder; A second classification process for classifying the elutriated 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.

[0053] <Mixing process> In the mixing step of this embodiment, starting materials are mixed to obtain a raw material mixed powder. In this embodiment, the starting materials 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.

[0054] In this embodiment, the europium compound preferably contains one selected from the group consisting of europium oxide, europium nitride, and europium fluoride, and more preferably contains europium oxide alone.

[0055] 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 elutriation or the like. Furthermore, any heterogeneous phase that does not absorb excess light may remain, and europium may be contained in this heterogeneous phase.

[0056] In this embodiment, from the perspective of further improving the applicability of the obtained composite to a small light-emitting device, the balance of performance in terms of luminance and excitation light blocking property, the amount of the europium compound is preferably used in an amount such that a in the above general formula in the charging ratio satisfies 0.035 < a < 0.060, more preferably 0.038 < a < 0.055. By using the europium compound in an amount such that a in the above general formula in the charging ratio is not less than the above lower limit value, the absorption rate of the phosphor powder can be further improved.

[0057] In this embodiment, from the perspective of further improving the applicability of the obtained composite to a small light-emitting device, the balance of performance in terms of luminance and excitation light blocking property, the amount of the strontium compound is preferably used in an amount such that b in the above general formula in the charging ratio satisfies 0.875 < b < 0.940, more preferably 0.880 < b < 0.935.

[0058] In this embodiment, from the perspective of further improving the applicability of the obtained composite to a small light-emitting device, the balance of performance in terms of luminance and excitation light blocking property, the amount of the calcium compound is preferably used in an amount such that c in the above general formula in the charging ratio satisfies 0.010 < c < 0.090, more preferably 0.015 < c < 0.080.

[0059] In the mixing step of this embodiment, the raw material mixed powder can be obtained, for example, by a method of dry-mixing starting materials or a method of wet-mixing in an inert solvent that does not substantially react with each starting material and then removing the solvent. As the mixing device, for example, a small mill mixer, a V-type mixer, a rocking mixer, a ball mill, a vibration mill, etc. can be used. After mixing using the device, the raw material mixed powder can be obtained by removing aggregates with a sieve as necessary. In order to suppress deterioration of the starting materials and unintentional mixing of oxygen, the mixing step of this embodiment is preferably carried out under a nitrogen atmosphere or in an environment with as little moisture (humidity) as possible.

[0060] <Firing Step> 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 1900°C or higher and 1950°C or lower, more preferably 1920°C or higher and 1940°C or lower, from the viewpoint of further improving the applicability of the resulting composite to a small light emitting device and the balance of brightness and excitation light blocking properties. By setting the firing temperature in the firing step within the above range, the median diameter D 50 The absorption rate can be further improved while reducing the

[0061] The firing time in the firing step of this embodiment is preferably 2 hours or more and 6 hours or less, more preferably 3 hours or more and 5 hours or less, from the viewpoint of further improving the applicability of the resulting composite to a small light emitting device and the performance balance between brightness and excitation light blocking property. By setting the firing time in the firing step within the above range, the median diameter D 50 The absorption rate can be further improved while reducing the

[0062] 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 controlling the oxygen concentration, the firing step of this embodiment is preferably carried out in a nitrogen gas atmosphere. That is, the firing step is preferably carried out in a nitrogen gas atmosphere with a pressure of 0.7 MPaG or more and 1.0 MPaG or less.

[0063] In the firing step of this embodiment, it is preferable to heat the mixture by filling it into 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 it is more preferable to use a tungsten container. This can prevent the generation of heterogeneous phases.

[0064] <First classification process> In the first classification step of this embodiment, the lumps obtained in the firing step are crushed and classified to obtain a fired powder. Since the fired powder obtained through the firing step is usually lumps, the lumps are pulverized to make them easier to handle. In the first classification step of this embodiment, the method for crushing the lumps is not particularly limited, but examples thereof include a method using a hammer or a mortar.Furthermore, the method for classifying the crushed lumps is also not particularly limited, but examples thereof include a method of passing the lumps through a sieve with openings of 800 to 900 μm.

[0065] <First crushing process> In the first pulverization step of this embodiment, the fired powder obtained in the first classification step is pulverized. After the first classification step, the first pulverization step is further performed to reduce the median diameter D 50 can be made smaller. In the first pulverization step of this embodiment, the method for pulverizing the sintered powder is not particularly limited, but examples thereof include a method in which the sintered powder is pulverized to a predetermined particle size using a general pulverizer such as a ball mill, a vibration mill, a jet mill, etc. Among these, it is preferable to use a jet mill in the first pulverization step.

[0066] <Annealing process> In the annealing step of this embodiment, the pulverized fired powder obtained in the first pulverization step is annealed to obtain an annealed powder, which removes distortions and defects due to rearrangement of elements, thereby further improving the luminescence properties of the phosphor powder.

[0067] 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, more preferably in an argon atmosphere, and is preferably performed under atmospheric pressure.

[0068] 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. The heat treatment time in the annealing step of this embodiment is preferably 6 hours or more and 10 hours or less, and more preferably 7 hours or more and 9 hours or less.

[0069] 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.

[0070] <Second crushing process> In the second pulverization step of this embodiment, the annealed powder obtained in the annealing step is pulverized. By performing the second pulverization step after the annealing step, the median diameter D 50 can be made smaller. In the second pulverization step of this embodiment, the method for pulverizing the sintered powder is not particularly limited, but examples thereof include a method in which the sintered powder is pulverized to a predetermined particle size using a general pulverizer such as a ball mill, a vibration mill, a jet mill, etc. Among these, it is preferable to use a ball mill in the second pulverization step.

[0071] The grinding time in the second grinding step of this embodiment is preferably 10 hours or more and 30 hours or less, more preferably 12 hours or more and 27 hours or less, from the viewpoint of further improving the applicability of the obtained composite to small light-emitting devices and the performance balance between brightness and excitation light blocking properties.

[0072] <Elutriation process> In the elutriation step of this embodiment, fine particles are removed from the pulverized annealed powder obtained in the second pulverization step by elutriation to obtain elutriated powder, which can remove fine particles that may deteriorate the luminescence properties of the phosphor powder, thereby further improving the luminescence properties.

[0073] The elutriation step of this embodiment is carried out by adding the pulverized annealed powder to a dispersion medium, preparing a dispersion and stirring the mixture, then precipitating the annealed powder in the dispersion and removing the supernatant. After removing the supernatant, the precipitate is collected by filtration and dried to obtain elutriated powder from which the fine particle powder has been removed. In the elutriation step of this embodiment, the preparation of the dispersion and the removal of the supernatant may be repeated. In the elutriation step of this embodiment, it is preferable to use an aqueous solution of sodium hexametaphosphate as the dispersion medium.

[0074] <Second classification process> In the second classification step of this embodiment, the elutriated powder obtained in the elutriation step is classified. 50 can be made smaller. In the second classification step of this embodiment, the method for classifying the elutriated powder is not particularly limited, but an example thereof is a method of passing the powder through a sieve with openings of 40 to 50 μm.

[0075] <Application> The phosphor powder of this embodiment can be suitably used in small light-emitting devices, particularly in micro LED displays, because the resulting composite has an improved applicability to small light-emitting devices and an improved performance balance between brightness and excitation light blocking properties.

[0076] <Complex> The composite of this embodiment includes the phosphor powder of this embodiment and a sealant that seals the phosphor powder. In the composite of this embodiment, the phosphor powder of this embodiment is dispersed in the sealant. The phosphor powder of this embodiment has an improved performance balance between the applicability to small light-emitting devices and the brightness and excitation light-blocking properties of the resulting composite, and therefore the composite of this embodiment has an improved performance balance between the applicability to small light-emitting devices and the brightness and excitation light-blocking properties of the resulting composite.

[0077] In the composite of this embodiment, the sealing material preferably contains one or more materials selected from the group consisting of silicone resin, epoxy resin, urethane resin, glass, and ceramics.

[0078] A method for producing the composite of this embodiment includes 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.

[0079] The composite of this embodiment can be formed into a sheet having a thickness of 100 μm or less. The phosphor powder of this embodiment in the composite of this embodiment has a median diameter D 50 Since the particle size is appropriately fine, between 0.1 μm and 5.0 μm, the phosphor powder in the sheet is uniformly dispersed and aggregation is suppressed, making the composite of this embodiment suitable for use in small light-emitting devices such as micro LED displays.

[0080] <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 composite of this embodiment has improved applicability to small light-emitting devices and a balance of brightness and excitation light-blocking properties, and therefore the light-emitting device of this embodiment has an improved balance of brightness and excitation light-blocking properties.

[0081] The composite of this embodiment has an improved applicability to small light-emitting devices and an improved performance balance between brightness and excitation light-blocking properties, and therefore, even when the light-emitting device of this embodiment is a small light-emitting device such as a micro LED display, the performance balance between brightness and excitation light-blocking properties is improved. When the light emitting device of this embodiment is a small light emitting device such as a micro LED display, the composite of this embodiment in the light emitting device of this embodiment is preferably a sheet having a thickness of 100 μm or less, more preferably a thickness of 50 μm or less.

[0082] 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]

[0083] 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.

[0084] Example 1 <Production of phosphor powder> 58.39 g of α-type silicon nitride (Si3N4, manufactured by UBE, SN-E10 grade), 51.19 g of aluminum nitride (AlN, manufactured by Tokuyama, E grade), and 10.99 g of europium oxide (Eu2O3, manufactured by Shin-Etsu Chemical Co., Ltd.) were weighed and premixed in a container.

[0085] 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, 3.09 g of calcium nitride (Ca3N2, manufactured by Materion) and 106.35 g of strontium nitride (Sr3N2, manufactured by Kojundo Chemical Laboratory, purity 2N) were weighed into the container and dry-mixed. This resulted in a mixed powder. The breakdown (molar ratio) of the amounts of each element in the raw material powder is shown in Table 1.

[0086] In a glove box, 230 g of the mixed powder was placed in a tungsten container. After closing the lid of the 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.

[0087] While continuing to evacuate, the temperature inside the electric furnace was increased 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. Then, in a nitrogen gas atmosphere, the temperature inside the electric furnace was increased to 1930°C, and after reaching 1930°C, heat treatment was carried out for 4 hours. Then, heating was stopped and the material was allowed to cool to room temperature. After cooling to room temperature, the mass was recovered from the container.

[0088] The collected lumps were crushed with a hammer, passed through a sieve with 850 μm openings, and then crushed in a supersonic jet crusher (PJM-80SP, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain a calcined powder. The crushing conditions were a sample feed rate of 100 g / min and a crushing air pressure of 0.5 MPa.

[0089] The resulting sintered powder was loaded into a 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, and 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 took 8 hours. After that, heating was stopped and the powder was cooled to room temperature. After cooling to room temperature, the annealed powder was recovered from the container.

[0090] The collected powder was pulverized in a ball mill using zirconia balls in an aqueous solvent for 26 hours to obtain an annealed powder.

[0091] The obtained annealed powder was added to an aqueous solution of sodium hexametaphosphate to prepare a dispersion, which was then stirred. The annealed powder in the dispersion was then allowed to settle, and the supernatant was removed. After removing the supernatant, the precipitate was collected by filtration, dried, and passed through a sieve with 45 μm openings to obtain elutriated powder from which fine particles had been removed. The preparation of the dispersion and the removal of the supernatant were repeated five times. In this way, the phosphor powder of Example 1 was obtained.

[0092] (Examples 2 to 5, Comparative Example 1) As shown in Table 1, phosphor powders of Examples 2 to 5 and Comparative Example 1 were obtained in the same manner as in Example 1, except that the breakdown (molar ratio) of the amounts of each element charged in the raw material powder was changed.

[0093] Example 6 As shown in Table 1, the phosphor powder of Example 6 was obtained in the same manner as in Example 3, except that the pulverization time in the second pulverization step was changed.

[0094] (Example 7, Comparative Example 2) As shown in Table 1, phosphor powders of Example 7 and Comparative Example 2 were obtained in the same manner as in Example 5, except that the pulverization time in the second pulverization step was changed.

[0095] <X-ray diffraction spectrum> For the X-ray diffraction spectra of the phosphor powders of each example and each comparative example, CuKα1 rays (CuKα with a wavelength of 1.5406 Å) were used as the radiation source, and the measurements were carried out using an X-ray diffractometer (manufactured by Rigaku Corporation, UltimaIV) under the conditions of a tube voltage of 40 kV, a tube current of 40 mA, a measurement range of 2θ = 10° to 140°, a sampling width of 0.008°, and a scanning speed of 0.008° / 0.1 sec. In the X-ray diffraction spectra of each obtained example and each comparative example, diffraction patterns identical to those of CaAlSiN3 crystals were observed, and it was confirmed that the main crystal phase had the same crystal structure as CaAlSiN3 crystals.

[0096] <Composition> First, for the phosphor powders of each example and each comparative example, the phosphor powders were dissolved by the pressurized acid decomposition method to prepare a sample solution. Next, quantitative analysis of elements was performed on the obtained sample solution using an ICP emission spectrometer (manufactured by Shimadzu Corporation, ICPE-9000), and the molar ratios of Eu, Sr, Ca, Al, and Si contained in the phosphor powders of each example and each comparative example were measured. The results are shown in Table 1. Furthermore, for the phosphor powders of each example and each comparative example, 0.03 g of the phosphor powder was weighed, and the oxygen and nitrogen contents were measured using an oxygen / nitrogen analyzer (manufactured by Horiba, Ltd., EMGA-920), and the molar ratios of N and O were determined. The results are shown in Table 1.

[0097] <Particle size> Using a particle size distribution measuring device by laser diffraction scattering method (manufactured by Microtrac Bell Corporation, MT3300EX II), the particle size distributions of the phosphor powders of each example and each comparative example were measured by the following method. Specifically, about 30 mg of the phosphor powder was added to 100 mL of an aqueous sodium hexametaphosphate solution with a concentration of 0.2%, and dispersion treatment was carried out using an Ultrasonic Homogenizer US-150E (manufactured by Nihon Seiki Seisakusho Co., Ltd., chip size φ20 mm, Amplitude 100%, oscillation frequency 19.5 KHz, amplitude about 31 μm) for 3 minutes, and then the measurement was carried out using the particle size distribution measuring device. From the obtained particle size distribution, the median diameter D of the phosphor powders of each example and each comparative example50 , 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 1.

[0098] <Relative fluorescence intensity> The relative fluorescence intensity of the phosphor powders of each Example and Comparative Example was measured using a spectrofluorometer (Hitachi High-Technologies Corporation, F-7000) calibrated with rhodamine B and a secondary standard light source. A solid sample holder attached to the spectrometer was used to measure the fluorescence spectrum at an excitation wavelength of 455 nm. The relative fluorescence intensity of the phosphor powders of each Example and Comparative Example was then calculated from the peak intensity of the obtained fluorescence spectrum. The results are shown in Table 1. Here, the relative fluorescence intensity was calculated by taking the peak height of the emission spectrum obtained by irradiating 455 nm monochromatic light onto YAG:Ce (P46Y3, manufactured by Mitsubishi Chemical Corporation) as 100% and expressing the peak intensity of the fluorescence spectrum as the relative peak intensity (%). In other words, the relative fluorescence intensity is a value relative to the standard sample.

[0099] <Absorptivity, peak wavelength, half-width> For each example and comparative example, the phosphor powder was filled into a concave cell so that the surface was smooth, and the concave cell was attached to the opening of an integrating sphere. Monochromatic light with a wavelength of 455 nm, split from a light source (Xe lamp), was introduced into the integrating sphere using an optical fiber as excitation light. The monochromatic light was then irradiated onto the phosphor powder, and the fluorescence spectrum of the phosphor powder was measured using a spectrophotometer (MCPD-7000, manufactured by Otsuka Electronics Co., Ltd.). The number of reflected excitation light photons (Qref) and the number of fluorescent photons (Qem) were calculated from the obtained fluorescence spectrum data for each Example and Comparative Example. The number of reflected excitation light photons was calculated in the wavelength range of 450 to 465 nm, and the number of fluorescent photons was calculated in the range of 465 to 800 nm. Using the same device, a standard reflector with a reflectance of 99% (Spectralon (registered trademark), 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 absorptance when the phosphor powder of each example and comparative example was irradiated with light having a wavelength of 455 nm was calculated based on the following formula. The results are shown in Table 1. Absorption rate = ((Qex-Qref) / Qex) x 100 The peak wavelength and half-width of the peak were determined from the obtained fluorescence spectrum of each example and comparative example. The results are shown in Table 1.

[0100] When the absorptance, peak wavelength, and half-width of a standard sample of β-SiAlON phosphor (NIMS Standard Green lot No. NSG1301, manufactured by SiAlON Co., Ltd.) were measured using the above measurement method, the absorptance was 74.4%, the peak wavelength was 543 nm, and the half-width was 53 nm. The measured values ​​of the absorptance, peak wavelength and half-width may fluctuate if the manufacturer, production lot number, etc. of the measuring device changes. Therefore, when measurements are performed using a measuring device with a different manufacturer, production lot number, etc. from the measuring device in this embodiment, the measured values ​​can be corrected based on the measured values ​​of a standard sample of the β-sialon phosphor.

[0101] <Diffuse reflectance> For each of the phosphor powders in the Examples and Comparative Examples, a UV-visible spectrophotometer (JASCO Corporation, V-650) equipped with an integrating sphere (JASCO Corporation, ISV-722) was used. Baseline correction was performed using a standard reflector (Spectralon®). A solid sample holder filled with the phosphor powder was then set, and the diffuse reflectance was measured in the wavelength range of 450 to 800 nm to obtain a diffuse reflectance spectrum. The diffuse reflectance at a wavelength of 700 nm was then calculated from the resulting diffuse reflectance spectrum. The results are shown in Table 1.

[0102] <Sheet formability> For each example and comparative example, the phosphor powder and silicone resin (OE6630, manufactured by Dow-Toray) were mixed in a mixer so that the phosphor powder was 40% by mass, to obtain a composite. The composite was then coated and cured at 150°C to form a 20 μm-thick sheet, and the sheet formability was evaluated according to the following criteria. The results are shown in Table 1. A: No aggregation of phosphor powder occurs, and uniform sheets can be formed. B: The phosphor powder aggregates, making it impossible to form a uniform sheet.

[0103] <External quantum efficiency QE and excitation light transmittance T during sheet molding> For each example and comparative example, the phosphor powder and silicone resin (OE6630, manufactured by Dow-Toray Industries, Inc.) were mixed in a mixer so that the phosphor powder was 40% by mass, yielding a composite. The composite was then coated and cured at 150°C to obtain a 20 μm-thick sheet. The sheet was then irradiated with light at a wavelength of 455 nm, and the emission spectrum of the light passing through the sheet was measured using a total luminous flux meter (HM series, manufactured by Otsuka Electronics Co., Ltd.). In the emission spectrum, the number of photons of the transmitted excitation light in the wavelength range of 401 to 492 nm was defined as Qt, and the number of fluorescent photons in the wavelength range of 493 to 800 nm was defined as Qem. The same device was then used to measure the emission spectrum of the 455 nm light used in the total luminous flux measurement. In the emission spectrum of the 455 nm light, the number of photons of the excitation light in the wavelength range of 401 to 492 nm was defined as Qex. Next, the value of (Qem / Qex) × 100 was calculated and used as the external quantum efficiency QE during sheet molding. Also, the value of (Qt / Qex) × 100 was calculated and used as the excitation light transmittance T. The results are shown in Table 1.

[0104] The ratio of raw materials used in each example and comparative example is shown in Table 1. The ratio is a molar ratio when Al is taken as 1.000. The composition of the phosphor powder of each example and comparative example is shown in Table 1. The composition is expressed as a molar ratio when Al is taken as 1.000.

[0105] [Table 1]

Claims

1. A phosphor powder comprising SCASN phosphor particles, The volume-based median diameter D of the phosphor powder measured by the laser diffraction scattering method ５０ is 0.1 μm or more and 5.0 μm or less, the peak wavelength of a fluorescence spectrum measured by a spectrophotometer when the phosphor powder is irradiated with light having a wavelength of 455 nm is 590.0 nm or more and 630.0 nm or less; The phosphor powder has an absorptivity of 80.0% or more when irradiated with light having a wavelength of 455 nm.

2. The SCASN phosphor particles are represented by the general formula Eu ａ Sr ｂ Ca ｃ AlSi ｄ N ｅ O ｆ 2. 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<d<1.300, 0≦e≦3.000, 0≦f≦3.000, 2.500≦e+f≦3.

500.

3. The phosphor powder according to claim 2 , wherein 0<a<0.

300.

4. The phosphor powder according to claim 2 , wherein b is 0.700<b<1.

000.

5. 3. The phosphor powder according to claim 2, wherein the molar ratio of b / (b+c) of the phosphor particles is 0.800 or more and 0.990 or less.

6. 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 The phosphor powder according to any one of claims 1 to 5, wherein the particle size is 0.01 µm or more and 3.0 µm or less.

7. The particle diameter D at which the cumulative value reaches 90% in the volume frequency particle size distribution by the laser diffraction scattering method of the phosphor powder ９０ The phosphor powder according to any one of claims 1 to 5, wherein the particle size is 1.0 µm or more and 10.0 µm or less.

8. 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 6. The phosphor powder according to claim 1, wherein the value of is 3.00 or less.

9. 6. The phosphor powder according to claim 1, wherein the half-width of the peak of the fluorescence spectrum is 85.0 nm or less.

10. 6. The phosphor powder according to claim 1, which has a diffuse reflectance of 80.0% or more at a wavelength of 700 nm as measured by an ultraviolet-visible spectrophotometer.

11. The phosphor powder according to any one of claims 1 to 5, which has an external quantum efficiency QE of 47.5% or more when formed into a sheet by the following method 1. (Method 1) The phosphor powder and silicone resin are mixed in a mixer so that the phosphor powder is 40% by mass to obtain a composite. The composite is then applied and cured at 150°C to obtain a sheet with a thickness of 20 μm. The sheet is then irradiated with light having a wavelength of 455 nm, and the emission spectrum of the light passing through the sheet is measured using a total luminous flux meter. The number of fluorescent photons in the wavelength range of 493 to 800 nm in the emission spectrum is defined as Qem. Next, the same device is used to measure the emission spectrum of the 455 nm light used in the total luminous flux measurement. Next, in the emission spectrum of the 455 nm light, the number of excitation light photons in the wavelength range of 401 to 492 nm is defined as Qex. Next, the value of (Qem / Qex)×100 is calculated and used as the external quantum efficiency QE during the sheet formation.

12. 6. The phosphor powder according to claim 1, wherein the excitation light transmittance T measured by the following method 2 is 11.0% or less. (Method 2) The phosphor powder and silicone resin are mixed in a mixer so that the phosphor powder is 40% by mass, resulting in a composite. The composite is then applied and cured at 150°C to obtain a sheet with a thickness of 20 μm. The sheet is then irradiated with light having a wavelength of 455 nm, and the emission spectrum of the light passing through the sheet is measured using a total luminous flux meter. In the emission spectrum, the number of photons of the transmitted excitation light in the wavelength range of 401 to 492 nm is defined as Qt. Next, the same device is used to measure the emission spectrum of 455 nm light used in the total luminous flux measurement. Next, in the emission spectrum of 455 nm light, the number of excitation light photons in the wavelength range of 401 to 492 nm is defined as Qex. Next, the value of (Qt / Qex) x 100 is calculated, and this is defined as the excitation light transmittance T.

13. The phosphor powder according to any one of claims 1 to 5, which can be used in a micro LED display.

14. A composite comprising the phosphor powder according to any one of claims 1 to 5 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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