Phosphor powder, composite, and light-emitting device

Abstract

Provided is a phosphor powder in which the balance of suitability, brightness, and excitation light blocking properties of a complex obtained from the phosphor powder with respect to a small-sized light-emitting device is improved. A phosphor powder containing SCASN phosphor particles, the phosphor powder having a volume-based median diameter (D50) of 0.1 [mu] m to 5.0 [mu] m (inclusive) as determined by a laser diffraction scattering method, and a peak wavelength of a fluorescence spectrum measured by a spectrophotometer when the phosphor powder is irradiated with light having a wavelength of 455 nm of 590.0 nm to 630.0 nm (inclusive), the absorption rate when the phosphor powder is irradiated with light having a wavelength of 455 nm is 80.0% or more.

Description

Technical Field

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

[0002] In order to manufacture white LEDs, research is underway into red phosphors that convert blue light from a blue LED chip into red light. As red phosphors, so-called SCASN and the like are known.

[0003] Patent Document 1 describes a phosphor characterized by comprising a phosphor having a general formula M a Sr b Ca c Al d Si e N f The crystal phase is shown at 4000mW / mm 2 The quantum efficiency maintenance rate under light excitation is 85% or more. In the general formula, M represents an activating element, 0<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.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2019-077800 Summary of the Invention

[0005] The present invention provides a phosphor powder in which the obtained composite has an improved performance balance in terms of applicability to small light-emitting devices, brightness, and excitation light-shielding properties, a composite in which the applicability to small light-emitting devices, brightness, and excitation light-shielding properties have an improved performance balance, and a light-emitting device in which the brightness and excitation light-shielding properties have an improved performance balance.

[0006] The present inventors have conducted extensive research to address the above-mentioned issues. As a result, they discovered that a phosphor powder can improve the performance balance between applicability to small-sized light-emitting devices, brightness, and excitation light shielding, thereby completing the present invention. The phosphor powder comprises SCASN phosphor particles, and the volume-based median particle size D of the phosphor powder, as determined by laser diffraction scattering, is 0.0447 W / cm2. 50 The phosphor powder has a particle size of 0.1 μm to 5.0 μm, a fluorescence spectrum having a peak wavelength of 590.0 nm to 630.0 nm as measured by a spectrophotometer when the phosphor powder is irradiated with light having a wavelength of 455 nm, and an absorptivity of 80.0% or more when the phosphor powder is irradiated with light having a wavelength of 455 nm.

[0007] According to the present invention, the following phosphor powder, composite, and light-emitting device can be provided. [1]

[0009] A phosphor powder comprising SCASN phosphor particles, wherein:

[0010] The volume-based median particle size D of the phosphor powder based on the laser diffraction scattering method is 50 is 0.1 μm or more and 5.0 μm or less,

[0011] When the phosphor powder 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,

[0012] The absorptivity of the phosphor powder when irradiated with light having a wavelength of 455 nm is 80.0% or more. [2]

[0014] The phosphor powder as described in [1], wherein

[0015] The SCASN phosphor particles contain a general formula of Eu a Sr b Ca c AlSi d N e O f Indicates phosphor particles with the following characteristics: 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]

[0017] The phosphor powder as described in [2], wherein

[0018] 0<a<0.300. [4]

[0020] The phosphor powder according to [2] or [3], wherein

[0021] 0.700<b<1.000. [5]

[0023] The phosphor powder according to any one of [2] to [4], wherein

[0024] The molar ratio of b / (b+c) of the phosphor particles is greater than or equal to 0.800 and less than or equal to 0.990. [6]

[0026] The phosphor powder according to any one of [1] to [5], wherein

[0027] In the volume frequency particle size distribution of the phosphor powder based on the laser diffraction scattering method, the particle size D at which the cumulative value becomes 10% is 10 It is 0.01 μm or more and 3.0 μm or less. [7]

[0029] The phosphor powder according to any one of [1] to [6], wherein

[0030] In the volume frequency particle size distribution of the phosphor powder based on the laser diffraction scattering method, the particle size D at which the cumulative value becomes 90% is 90 It is 1.0 μm or more and 10.0 μm or less. [8]

[0032] The phosphor powder according to any one of [1] to [7], wherein

[0033] In the volume frequency particle size distribution of the phosphor powder by the laser diffraction scattering method, the particle size D at which the cumulative value becomes 10% is 10 , become 90% of the particle size D 90 , median particle size D 50 ,(D 90 -D 10 ) / D 50 The value is below 3.00. [9]

[0035] The phosphor powder according to any one of [1] to [8], wherein

[0036] The half-value width of the peak of the fluorescence spectrum is 85.0 nm or less.

[10]

[0038] The phosphor powder according to any one of [1] to [9], wherein

[0039] The diffuse reflectance at a wavelength of 700 nm measured by an ultraviolet-visible spectrophotometer is 80.0% or more.

[11]

[0041] The phosphor powder according to any one of [1] to

[10] , wherein

[0042] The external quantum efficiency QE during sheet molding by the following method 1 is 47.5% or more.

[0043] (Method 1)

[0044] The phosphor powder and the silicone resin are mixed by a mixer in such a manner that the phosphor powder becomes 40% by mass to obtain a composite. Then, the composite is applied and cured at 150°C to obtain a sheet with a thickness of 20 μm. Then, the sheet is irradiated with light of a wavelength of 455 nm, and the luminescence spectrum of the light passing through the sheet is measured using a full-beam meter. Then, in the luminescence spectrum, the number of fluorescent photons in the wavelength range of 493 to 800 nm is set as Qem. Then, the luminescence spectrum of the 455 nm light used in the full-beam measurement is measured using the same device. Then, in the luminescence spectrum of the 455 nm light, the number of excitation light photons in the wavelength range of 401 to 492 nm is set as Qex. Then, the value of (Qem / Qex)×100 is calculated and used as the external quantum efficiency QE when the sheet is formed.

[12]

[0046] The phosphor powder according to any one of [1] to

[11] , wherein

[0047] The excitation light transmittance T by the following method 2 is 11.0% or less.

[0048] (Method 2)

[0049] The phosphor powder and the silicone resin are mixed by a mixer in such a manner that the phosphor powder becomes 40% by mass to obtain a composite. Then, the composite is applied and cured at 150°C to obtain a sheet with a thickness of 20 μm. Then, the sheet is irradiated with light of a wavelength of 455 nm, and the luminescence spectrum of the light passing through the sheet is measured using a full-beam meter. Then, in the luminescence spectrum, the number of excitation transmitted light photons in the wavelength range of 401 to 492 nm is set as Qt. Then, the luminescence spectrum of the 455 nm light used in the full-beam measurement is measured using the same device. Then, in the luminescence spectrum of the 455 nm light, the number of excitation light photons in the wavelength range of 401 to 492 nm is set as Qex. Then, the value of (Qt / Qex)×100 is calculated and used as the excitation light transmittance T.

[13]

[0051] The phosphor powder as described in any one of [1] to

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

[14]

[0053] A composite comprising the phosphor powder according to any one of [1] to

[13] and a sealing material that seals the phosphor powder.

[15]

[0055] A light-emitting device comprising:

[0056] a light-emitting element that emits excitation light; and

[0057] The complex as described in

[14] converts the wavelength of the excitation light.

[0058] Effects of the Invention

[0059] According to the present invention, there can be provided a phosphor powder in which the obtained composite has an improved performance balance in terms of applicability to small light-emitting devices, brightness, and excitation light-shielding properties, a composite in which the applicability to small light-emitting devices, brightness, and excitation light-shielding properties have an improved performance balance, and a light-emitting device in which the brightness and excitation light-shielding properties have an improved performance balance. DETAILED DESCRIPTION

[0060] Hereinafter, embodiments of the present invention will be described in detail.

[0061] In the present embodiment, “A to B” indicating a numerical range means A or more and B or less, unless otherwise specified.

[0062] <Phosphor powder>

[0063] The phosphor powder of this embodiment contains SCASN phosphor particles.

[0064] The SCASN phosphor particles of this embodiment are composed of (Si, Al)-N4 regular tetrahedral bonds, in which a portion of the Ca atoms in the gaps of the skeleton are replaced by Sr atoms and solid-dissolved, and the Ca 2+ Eu, a part of which functions as a luminescence center 2+ Replaced by other activated elements.

[0065] In the phosphor powder of this embodiment, the volume-based median diameter D of the phosphor powder is 1.5747 W / cm2 by the laser diffraction scattering method. 50 The particle size is 0.1 μm to 5.0 μm, 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 to 630.0 nm, and the absorptivity when the phosphor powder is irradiated with light of a wavelength of 455 nm is 80.0% or more.

[0066] According to the research conducted by the present inventors, it has been found that the phosphor powder containing SCASN phosphor particles has the following tendency: the median particle size D 50 The smaller the size, the better the applicability of the obtained composite to small-sized light-emitting devices and the excitation light shielding ability, but the brightness of the obtained composite decreases.

[0067] As a result of further repeated studies, the present inventors discovered that, in a phosphor powder 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 obtained composite.

[0068] The present inventors have conducted further research based on the above findings and have found that the volume-based median diameter D of the phosphor powder based on the laser diffraction scattering method can be 50 By setting the optical density to be greater than 0.1 μm and less than 5.0 μm, 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 be greater than 590.0 nm and less than 630.0 nm, and setting the absorptivity when the phosphor powder is irradiated with light of a wavelength of 455 nm to be greater than 80.0%, the applicability of the obtained composite to small light-emitting devices, the brightness and the performance balance of the excitation light shielding property can be improved, thereby completing the present invention.

[0069] From the viewpoint of further improving the brightness of the obtained composite, the volume-based median diameter D of the phosphor powder of this embodiment based on the laser diffraction scattering method is 50 It is 0.1 μm or more, preferably 0.5 μm or more, more preferably 0.8 μm or more, further preferably 1.0 μm or more, further preferably 1.2 μm or more, further preferably 1.5 μm or more, further preferably 1.8 μm or more, further preferably 2.0 μm or more.

[0070] Furthermore, from the viewpoint of further improving the applicability of the obtained composite to small-sized light-emitting devices and the excitation light shielding performance, the volume-based median diameter D of the phosphor powder of this embodiment based on the laser diffraction scattering method is 50 It is 5.0 μm or less, preferably 4.5 μm or less, more preferably 4.2 μm or less, further preferably 3.9 μm or less, further preferably 3.7 μm or less, further preferably 3.0 μm or less, further preferably 2.5 μm or less, further preferably 2.0 μm or less.

[0071] From the viewpoint of further improving the performance balance between the applicability of the obtained composite to a small light-emitting device, brightness, and excitation light shielding, the volume-based median particle size D of the phosphor powder of this embodiment based on the laser diffraction scattering method is 50 It 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, further preferably 1.0 μm or more and 3.7 μm or less, and further preferably 1.2 μm or more and 3.0 μm or less.

[0072] Furthermore, from the viewpoint of further improving the compatibility of the obtained composite for small-sized light-emitting devices and the performance balance between brightness and excitation light shielding, the volume-based median particle size D of the phosphor powder of this embodiment based on the laser diffraction scattering method is 1.5747 W / cm2. 50 It is 0.1 μm or more and 5.0 μm or less, preferably 0.3 μm or more and 4.0 μm or less, more preferably 0.5 μm or more and 3.0 μm or less, further preferably 0.8 μm or more and 2.5 μm or less, further preferably 1.0 μm or more and 2.0 μm or less, further preferably 1.2 μm or more and 1.7 μm or less.

[0073] Furthermore, from the viewpoint of further improving the compatibility of the obtained composite with respect to a small-sized light-emitting device, the brightness and the excitation light shielding performance balance, and further improving the brightness of the obtained composite, the volume-based median particle size D of the phosphor powder of this embodiment based on the laser diffraction scattering method is 50 It 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 1.0 μm or more and 4.2 μm or less, further preferably 1.5 μm or more and 3.7 μm or less, and further preferably 2.0 μm or more and 3.0 μm or less.

[0074] In this embodiment, the median particle size D of the phosphor powder is 50 For example, it can be obtained by the following method.

[0075] First, about 30 mg of phosphor powder was added to 100 mL of a 0.2% sodium hexametaphosphate aqueous solution. This was then dispersed for 3 minutes using an Ultrasonic Homogenizer US-150E (manufactured by NIHONSEIKI KAISHA LTD., chip size φ20 mm, amplitude 100%, vibration frequency 19.5 kHz, amplitude approximately 31 μm). The particle size distribution was then measured using a laser diffraction scattering method. The median particle size D of the phosphor powder was then determined based on the obtained particle size distribution. 50 .

[0076] From the perspective of further improving the performance balance between color gamut and brightness, the peak wavelength of the fluorescence spectrum measured by a spectrophotometer when the phosphor powder of this embodiment is irradiated with light of a wavelength of 455 nm 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.

[0077] In this embodiment, the peak wavelength of the phosphor powder can be determined by, for example, the following method.

[0078] First, a concave groove was filled with phosphor powder to smooth its surface. After the concave groove was mounted on the opening of an integrating sphere, an optical fiber was used to introduce monochromatic light with a wavelength of 455 nm from a light source (Xe lamp) into the integrating sphere as excitation light. Next, the monochromatic light was irradiated onto the phosphor powder, and its fluorescence spectrum was measured using a spectrophotometer. The peak wavelength of the phosphor powder was then determined from the obtained fluorescence spectrum.

[0079] From the viewpoint of further improving the brightness of the obtained composite, the absorptivity when the phosphor powder of this embodiment is irradiated with light of a wavelength of 455 nm is 80.0% or more, preferably 80.5% or more, more preferably 81.0% or more, further preferably 83.0% or more, and further preferably 85.0% or more.

[0080] The upper limit of the absorptivity when the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm is not particularly limited, and may be, for example, 99.0% or less, 95.0% or less, or 90.0% or less.

[0081] From the perspective of further improving the performance balance of the obtained composite for small light-emitting devices, brightness and excitation light blocking properties, the absorption rate when the phosphor powder of this embodiment is irradiated with light of a wavelength of 455nm is preferably 80.0% or more and 99.0% or less, more preferably 80.5% or more and 95.0% or less, and further preferably 81.0% or more and 90.0% or less.

[0082] Furthermore, from the viewpoint of further improving the applicability of the obtained composite to small light-emitting devices while balancing the performance of brightness and excitation light shielding, the absorption rate when the phosphor powder of this embodiment is irradiated with light of 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, further preferably 81.0% or more and 90.0% or less, and further preferably 81.0% or more and 86.0% or less.

[0083] Furthermore, from the viewpoint of further improving the brightness of the obtained composite while balancing the applicability of the obtained composite to small-scale light-emitting devices, brightness, and excitation light shielding properties, the absorption rate when the phosphor powder of this embodiment is irradiated with light of 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, further preferably 83.0% or more and 92.0% or less, further preferably 85.0% or more and 91.0% or less, and further preferably 86.0% or more and 90.0% or less.

[0084] In this embodiment, the absorption rate of the phosphor powder can be obtained by, for example, the following method.

[0085] Based on the data of the fluorescence spectrum obtained in the same manner as the method for measuring the peak wavelength, the luminous intensity of the phosphor powder is determined, and the number of excitation reflected light photons (Qref) and the number of fluorescence photons (Qem) are calculated. The number of excitation reflected 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. In addition, using the same device, a standard reflector with a reflectivity of 99% is installed at the opening of the integrating sphere, and the spectrum of the excitation light with a wavelength of 455 nm is measured. At this time, the number of excitation light photons (Qex) is calculated based on the spectrum in the wavelength range of 450 to 465 nm. Next, based on the above calculation results, the absorbance when the phosphor powder is irradiated with light of a wavelength of 455 nm is determined based on the calculation formula shown below.

[0086] Absorption rate = ((Qex-Qref) / Qex) × 100

[0087] The phosphor powder of this embodiment can be obtained by appropriately selecting the raw materials, the ratio of each raw material used, and the manufacturing steps and conditions. Regarding the selection of raw materials and the ratio of the raw materials, it is preferable to use a raw material containing more Eu or a raw material containing more Sr. Regarding the manufacturing steps and conditions, it is preferable to extend the pulverization time in the second pulverization step. Details of these will be described later.

[0088] <Crystal structure, elemental composition, etc.>

[0089] The crystalline phase of the phosphor powder can be confirmed by powder X-ray diffraction. While a single crystalline phase is preferred, heterogeneous phases may be present as long as they do not significantly affect the properties of the phosphor. The presence of heterogeneous phases can be determined, for example, by powder X-ray diffraction based on the presence or absence of peaks other than those associated with the target crystalline phase.

[0090] The SCASN phosphor particles in the phosphor powder of this embodiment preferably contain a phosphor having the general formula Eu a Sr b Ca c AlSi d N e O f Indicates phosphor particles with the following characteristics: 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.

[0091] In the above general formula, a is preferably 0<a<0.300, more preferably 0.001<a<0.200, further preferably 0.010<a<0.150, further preferably 0.020<a<0.100, further preferably 0.030<a<0.080, further preferably 0.035<a<0.060.

[0092] In the above general formula, b is preferably 0.700<b<1.000, more preferably 0.800<b<0.990, further preferably 0.850<b<0.970, further preferably 0.860<b<0.960, further preferably 0.870<b<0.950.

[0093] As another indicator of the concept 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, further preferably 0.900 or more and 0.990 or less, further preferably 0.910 or more and 0.985 or less, and further preferably 0.915 or more and 0.985 or less.

[0094] In the above general formula, c is preferably 0<c<1.000, more preferably 0.001<c<0.500, further preferably 0.005<c<0.300, further preferably 0.010<c<0.200, further preferably 0.015<c<0.100.

[0095] In the above general formula, d is preferably 0.800<d<1.200, more preferably 0.900<d<1.100, further preferably 0.950<d<1.080, further preferably 0.980<d<1.060, further preferably 1.000<d<1.050.

[0096] In the above general formula, e is preferably 0<e<3.000, more preferably 1.000<e<3.000, further preferably 2.000<e<3.000, further preferably 2.100<e<2.900, further preferably 2.200<e<2.850, further preferably 2.300<e<2.800.

[0097] In the above general formula, f is preferably 0<f<3.000, more preferably 0.010<f<2.000, further preferably 0.050<f<1.500, further preferably 0.100<f<1.000, further preferably 0.200<f<0.900, further preferably 0.300<f<0.800.

[0098] 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, further preferably 0.950<a+b+c<1.050, and further preferably 0.980<a+b+c<1.030.

[0099] In the above general formula, e+f is preferably 2.500<e+f<3.500, more preferably 2.700<e+f<3.400, further preferably 2.900<e+f<3.300, further preferably 3.000<e+f<3.250, further preferably 3.020<e+f<3.230.

[0100] In this embodiment, the molar ratio of Eu, Sr, Ca, Al and Si in the molar ratio of each element contained in the phosphor powder can be determined, for example, by dissolving the phosphor powder by a pressurized acid decomposition method to prepare a sample solution, and using an ICP emission spectrometer to perform quantitative elemental analysis on the obtained sample solution.

[0101] In this embodiment, the molar ratio of N and O in the molar ratio of each element contained in the phosphor powder can be determined by, for example, weighing 0.03 g of the phosphor powder and measuring the oxygen and nitrogen contents using an oxygen / nitrogen analyzer.

[0102] <Particle size>

[0103] From the viewpoint of further improving the performance balance between the applicability of the obtained composite to a small light-emitting device and the brightness and excitation light shielding property, the particle size D at which the cumulative value reaches 10% in the volume frequency particle size distribution of the phosphor powder of this embodiment based on the laser diffraction scattering method is 10 It 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, further preferably 0.3 μm or more and 2.0 μm or less, and further preferably 0.5 μm or more and 1.5 μm or less.

[0104] Furthermore, from the viewpoint of further improving the compatibility of the obtained composite for small-sized light-emitting devices and the performance balance between brightness and excitation light shielding, the particle size D at which the cumulative value reaches 10% in the volume frequency particle size distribution of the phosphor powder of this embodiment based on the laser diffraction scattering method is set to be 0. 10 It is preferably 0.01 μm to 3.0 μm, more preferably 0.1 μm to 2.0 μm, further preferably 0.3 μm to 1.5 μm, further preferably 0.5 μm to 1.0 μm, further preferably 0.5 μm to 0.8 μm.

[0105] Furthermore, from the viewpoint of further improving the compatibility of the obtained composite with respect to a small-sized light-emitting device, the brightness and the excitation light shielding performance balance, and further improving the brightness of the obtained composite, the particle size D at which the cumulative value reaches 10% in the volume frequency particle size distribution of the phosphor powder of this embodiment based on the laser diffraction scattering method is set to be 0. 10 It 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, further preferably 0.5 μm or more and 2.0 μm or less, and further preferably 1.0 μm or more and 1.5 μm or less.

[0106] From the viewpoint of further improving the performance balance between the applicability of the obtained composite to a small-sized light-emitting device, the brightness, and the excitation light shielding property, the particle size D at which the cumulative value reaches 90% in the volume frequency particle size distribution of the phosphor powder of this embodiment based on the laser diffraction scattering method is 90 It 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, further preferably 2.0 μm or more and 6.0 μm or less, and further preferably 2.3 μm or more and 5.0 μm or less.

[0107] Furthermore, from the viewpoint of further improving the compatibility of the obtained composite for small-sized light-emitting devices and the performance balance between brightness and excitation light shielding, the particle size D at which the cumulative value reaches 90% in the volume frequency particle size distribution of the phosphor powder of this embodiment based on the laser diffraction scattering method is set to be 0. 90 It is preferably 1.0 μm to 10.0 μm, more preferably 1.5 μm to 7.0 μm, further preferably 2.0 μm to 5.0 μm, further preferably 2.3 μm to 4.0 μm, further preferably 2.4 μm to 3.0 μm.

[0108] Furthermore, from the viewpoint of further improving the compatibility of the obtained composite with respect to a small-sized light-emitting device, the brightness and the excitation light shielding performance balance, and further improving the brightness of the obtained composite, in the volume frequency particle size distribution of the phosphor powder of this embodiment based on the laser diffraction scattering method, the particle size D at which the cumulative value reaches 90% is set. 90 It is preferably 1.0 μm to 10.0 μm, more preferably 2.0 μm to 8.0 μm, further preferably 3.0 μm to 6.0 μm, further preferably 3.5 μm to 5.5 μm, further preferably 4.0 μm to 5.0 μm.

[0109] From the viewpoint of further improving the performance balance between the applicability of the obtained composite to a small-sized light-emitting device, brightness, and excitation light shielding, in the volume frequency particle size distribution of the phosphor powder of this embodiment based on the laser diffraction scattering method, (D 90 -D 10 ) / D 50 The value of is preferably 3.00 or less, more preferably 2.50 or less, further preferably 2.00 or less, further preferably 1.80 or less, further preferably 1.70 or less, further preferably 1.60 or less.

[0110] In the volume frequency particle size distribution of the phosphor powder of this embodiment based on the laser diffraction scattering method, (D 90 -D 10 ) / D 50 The lower limit of the value of is not particularly limited, and 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.

[0111] Furthermore, from the viewpoint of further improving the performance balance between the applicability of the obtained composite to a small-sized light-emitting device, brightness, and excitation light shielding, in the volume frequency particle size distribution of the phosphor powder of this embodiment based on the laser diffraction scattering method, (D 90 -D 10 ) / D 50 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, further preferably 1.00 or more and 2.00 or less, further preferably 1.10 or more and 1.80 or less, further preferably 1.20 or more and 1.70 or less, further preferably 1.25 or more and 1.60 or less.

[0112] In this embodiment, the particle size D at which the cumulative value of the volume frequency particle size distribution of the phosphor powder based on the laser diffraction scattering method reaches 10% is 10 , the particle size D at which the cumulative value reaches 90% 90 and (D 90 -D 10 ) / D 50 The value of the median particle size D can be determined based on the 50 The particle size distribution was obtained in the same manner as above.

[0113] <Luminescence Characteristics>

[0114] From the viewpoint of further improving the luminescent properties, the half-value width of the peak of the fluorescence spectrum measured by a spectrophotometer when the phosphor powder of this embodiment is irradiated with light of a wavelength of 455 nm is preferably 85.0 nm or less, more preferably 83.0 nm or less, further preferably 82.0 nm or less, and further preferably 81.0 nm or less.

[0115] The lower limit of the half-value width of the peak of the fluorescence spectrum measured by a spectrophotometer when the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm is not particularly limited, and may be, for example, 70.0 nm or more or 75.0 nm or more.

[0116] Furthermore, from the viewpoint of further improving the luminescence characteristics, the half-value width of the peak of the fluorescence spectrum measured by a spectrophotometer when the phosphor powder of this embodiment is irradiated with light of a wavelength of 455 nm is preferably greater than or equal to 70.0 nm and less than or equal to 85.0 nm, more preferably greater than or equal to 70.0 nm and less than or equal to 83.0 nm, further preferably greater than or equal to 75.0 nm and less than or equal to 82.0 nm, and further preferably greater than or equal to 75.0 nm and less than or equal to 81.0 nm.

[0117] In the present embodiment, the half-value width of the peak of the phosphor powder can be determined from, for example, a fluorescence spectrum obtained in the same manner as the above-mentioned method of measuring the peak wavelength.

[0118] From the viewpoint of further improving luminescent properties, the diffuse reflectance of the phosphor powder of this embodiment at a wavelength of 700 nm measured by an ultraviolet-visible spectrophotometer is preferably 80.0% or more, more preferably 82.0% or more, further preferably 84.0% or more, and further preferably 85.0% or more.

[0119] 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, and may be, for example, 99.0% or less, or 95.0% or less.

[0120] Furthermore, from the viewpoint of further improving the luminescent properties, the diffuse reflectance of the phosphor powder of this embodiment at a wavelength of 700 nm, as 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, further preferably 84.0% or more and 95.0% or less, and further preferably 85.0% or more and 95.0% or less.

[0121] In this embodiment, the diffuse reflectance of the phosphor powder can be obtained by, for example, the following method.

[0122] First, using a UV-visible spectrophotometer equipped with an integrating sphere, baseline calibration was performed using a standard reflector. A solid sample holder filled with phosphor powder was placed and diffuse reflectance was measured over a wavelength range of 450 to 800 nm to obtain a diffuse reflectance spectrum. Next, the diffuse reflectance at a wavelength of 700 nm was determined from the obtained diffuse reflectance spectrum.

[0123] From the viewpoint of further improving the luminescence characteristics, when the fluorescence intensity of the standard sample YAG:Ce is set to 100%, the relative fluorescence intensity of the fluorescence spectrum measured by a spectrophotometer when the phosphor powder of this embodiment is irradiated with light of a wavelength of 455 nm is preferably 120.0% or more, more preferably 140.0% or more, further preferably 150.0% or more, further preferably 155.0% or more, and further preferably 156.0% or more.

[0124] The upper limit of the relative fluorescence intensity of the fluorescence spectrum measured by a spectrophotometer when the phosphor powder of this embodiment is irradiated with light having a wavelength of 455 nm is not particularly limited, and may be, for example, 250.0% or less or 200.0% or less.

[0125] Furthermore, from the viewpoint of further improving the luminescence characteristics, when the fluorescence intensity of the standard sample YAG:Ce is set to 100%, the relative fluorescence intensity of the fluorescence spectrum measured by a spectrophotometer when the phosphor powder of this embodiment is irradiated with light of a wavelength of 455 nm is preferably greater than or equal to 120.0% and less than or equal to 250.0%, more preferably greater than or equal to 140.0% and less than or equal to 250.0%, further preferably greater than or equal to 150.0% and less than or equal to 250.0%, further preferably greater than or equal to 155.0% and less than or equal to 200.0%, and further preferably greater than or equal to 156.0% and less than or equal to 200.0%.

[0126] In this embodiment, as a method of measuring the relative fluorescence intensity of the phosphor powder, for example, the following method can be listed.

[0127] First, using a spectrofluorometer calibrated with rhodamine B and a secondary standard light source, and using the solid sample holder included with the spectrofluorometer, the fluorescence spectrum of the phosphor powder was measured at an excitation wavelength of 455 nm. Next, the relative fluorescence intensity was calculated by expressing the peak intensity of the fluorescence spectrum as relative peak intensity (%), with the peak height of the emission spectrum obtained by irradiating YAG:Ce with 455 nm monochromatic light set as 100%.

[0128] External Quantum Efficiency (QE)

[0129] From the viewpoint of further improving the brightness of the obtained composite, the external quantum efficiency QE of the phosphor powder of this embodiment during sheet molding is preferably 47.5% or more, more preferably 48.0% or more, further preferably 49.5% or more, and further preferably 50.5% or more.

[0130] The upper limit of the external quantum efficiency QE of the phosphor powder of the present embodiment when formed into a sheet is not particularly limited, and may be, for example, 70.0% or less, or 60.0% or less.

[0131] Furthermore, from the viewpoint of further improving the brightness of the obtained composite, the external quantum efficiency QE of the phosphor powder of this embodiment during sheet molding is preferably greater than 47.5% and less than 70.0%, more preferably greater than 48.0% and less than 70.0%, further preferably greater than 49.5% and less than 60.0%, and further preferably greater than 50.5% and less than 60.0%.

[0132] In the present embodiment, the external quantum efficiency QE of the phosphor powder during tablet molding can be determined, for example, by the following method.

[0133] First, a composite is obtained by mixing phosphor powder and silicone resin by a mixer in such a manner that the phosphor powder becomes 40% by mass. Then, the composite is applied and cured at 150°C to obtain a sheet with a thickness of 20 μm. Next, the sheet is irradiated with light of a wavelength of 455 nm, and the luminescence spectrum of the light passing through the sheet is measured using a total beam meter. Next, in the luminescence spectrum, the number of fluorescent photons in the wavelength range of 493 to 800 nm is set as Qem. Next, the luminescence spectrum of the 455 nm light used in the full beam measurement is measured using the same device. Next, in the luminescence spectrum of the 455 nm light, the number of excitation light photons in the wavelength range of 401 to 492 nm is set as Qex. Next, the value of (Qem / Qex)×100 is calculated and used as the external quantum efficiency QE when the sheet is formed.

[0134] <Excitation light transmittance T>

[0135] From the viewpoint of further improving the excitation light blocking property of the obtained composite, the excitation light transmittance T of the phosphor powder of this embodiment is preferably 11.0% or less, more preferably 10.0% or less, further preferably 9.5% or less, further preferably 9.0% or less, further preferably 8.5% or less.

[0136] The lower limit of the excitation light transmittance T of the phosphor powder of the present embodiment is not particularly limited, and may be, for example, 1.0% or more, or 3.0% or more.

[0137] Furthermore, from the viewpoint of further improving the excitation light shielding property of the obtained composite, the excitation light transmittance T of the phosphor powder of this embodiment is preferably greater than 1.0% and less than 11.0%, more preferably greater than 1.0% and less than 10.0%, further preferably greater than 3.0% and less than 9.5%, further preferably greater than 3.0% and less than 9.0%, further preferably greater than 3.0% and less than 8.5%.

[0138] In the present embodiment, the excitation light transmittance T of the phosphor powder can be obtained by, for example, the following method.

[0139] First, a composite is obtained by mixing phosphor powder and silicone resin by a mixer in such a manner that the phosphor powder becomes 40% by mass. Then, the composite is applied and cured at 150°C to obtain a sheet with a thickness of 20 μm. Next, the sheet is irradiated with light of a wavelength of 455 nm, and the luminescence spectrum of the light passing through the sheet is measured using a total beam meter. Next, in the luminescence spectrum, the number of excitation transmitted light photons in the wavelength range of 401 to 492 nm is set as Qt. Next, the luminescence spectrum of the 455 nm light used in the full beam measurement is measured using the same device. Next, in the luminescence spectrum of the 455 nm light, the number of excitation light photons in the wavelength range of 401 to 492 nm is set as Qex. Next, the value of (Qt / Qex)×100 is calculated and used as the excitation light transmittance T.

[0140] <Method for producing phosphor powder>

[0141] The phosphor powder of this embodiment can be obtained by appropriately selecting the raw materials, the ratio of each raw material to be used, the production steps / production conditions, etc. Specifically, the phosphor powder of this embodiment can be preferably produced by the following method:

[0142] A mixing step of mixing starting materials to obtain a raw material mixed powder;

[0143] · Firing process, in which the raw material mixed powder is fired to obtain a block;

[0144] The first classification process is to crush and classify the lumps to obtain calcined powder;

[0145] The first pulverizing step is to pulverize the calcined powder;

[0146] Annealing process: annealing the crushed fired powder to obtain annealed powder;

[0147] The second crushing process is to crush the annealing powder;

[0148] A washing step, in which fine particles are removed from the crushed annealed powder by washing to obtain washed powder;

[0149] The second classification process is to classify the washed powder.

[0150] Furthermore, additional steps other than these may be included when producing the phosphor powder.

[0151] <Mixing process>

[0152] In the mixing step of the present embodiment, starting materials are mixed to obtain a raw material mixed powder.

[0153] In this embodiment, the starting material preferably includes all of europium compounds, strontium compounds, calcium compounds, silicon nitride, and aluminum nitride, and more preferably includes all of europium oxide, strontium nitride, calcium nitride, silicon nitride, and aluminum nitride.

[0154] The form of each starting material in this embodiment is preferably powder.

[0155] In the present embodiment, the europium compound preferably includes one selected from the group consisting of europium oxide, europium nitride, and europium fluoride alone, and more preferably includes europium oxide alone.

[0156] During the firing process of this embodiment, europium is divided into solid-solution europium, volatilized europium, and residual europium as a heterophase component. The heterophase component containing europium can be removed by washing, etc. Furthermore, as long as the heterophase does not absorb excess light, it may remain, or europium may be contained in the heterophase.

[0157] In this embodiment, from the perspective of further improving the performance balance between the compatibility of the resulting composite for small light-emitting devices and the brightness and excitation light shielding properties, the europium compound is preferably used in an amount such that a in the general formula of the packing ratio is preferably 0.035 < a < 0.060, and more preferably 0.038 < a < 0.055. By using the europium compound in an amount such that a in the general formula of the packing ratio is equal to or greater than the lower limit, the absorption rate of the phosphor powder can be further improved.

[0158] In this embodiment, from the perspective of further improving the performance balance of the applicability, brightness and excitation light blocking properties of the obtained complex for small light-emitting devices, the amount of strontium compound is preferably used in an amount such that b in the general formula of the filling ratio becomes preferably 0.875<b<0.940, and more preferably 0.880<b<0.935.

[0159] In this embodiment, from the perspective of further improving the performance balance of the obtained complex in terms of applicability to small light-emitting devices, brightness, and excitation light blocking properties, the amount of calcium compound is preferably used in an amount such that c in the general formula of the filling ratio becomes preferably 0.010<c<0.090, and more preferably 0.015<c<0.080.

[0160] In the mixing step of this embodiment, the raw material mixed powder can be obtained by, for example, dry mixing of the starting materials or wet mixing in an inert solvent that is substantially non-reactive with the starting materials followed by solvent removal. 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 through a sieve as needed to obtain the raw material mixed powder.

[0161] In order to suppress deterioration of the starting materials or unintended incorporation of oxygen, the mixing step of the present embodiment is preferably performed under a nitrogen atmosphere or an environment with as little water (humidity) as possible.

[0162] <Firing process>

[0163] In the firing step of the present embodiment, the raw material mixed powder obtained in the mixing step is fired to obtain fired powder.

[0164] From the perspective of further improving the performance balance between the compatibility of the obtained composite for small-sized light-emitting devices, brightness, and excitation light shielding, the firing temperature in the firing step of this embodiment is preferably 1900°C or higher and 1950°C or lower, and more preferably 1920°C or higher and 1940°C or lower. By setting the firing temperature in the firing step within the above range, the median particle size D of the phosphor powder can be further reduced. 50 At the same time, further improve the absorption rate.

[0165] From the perspective of further improving the performance balance between the compatibility of the obtained composite for small-sized light-emitting devices, brightness, and excitation light shielding, the firing time in the firing step of this embodiment is preferably 2 hours to 6 hours, more preferably 3 hours to 5 hours. By setting the firing time in the firing step within the above range, the median particle size D of the phosphor powder can be further reduced. 50 At the same time, further improve the absorption rate.

[0166] The pressure during the firing step of this embodiment is preferably 0.7 MPaG to 1.0 MPaG, more preferably 0.8 MPaG to 0.9 MPaG. From the perspective of controlling oxygen concentration, the firing step of this embodiment is preferably performed under a nitrogen atmosphere. That is, the firing step is preferably performed under a nitrogen atmosphere with a pressure of 0.7 MPaG to 1.0 MPaG.

[0167] In the firing process of this embodiment, it is preferred to fill the mixture into a container that is not easily reactive with the raw material mixed powder and heat it during firing. Specifically, it is preferred to use a high melting point container, more preferably a tungsten container. This can suppress the generation of heterogeneous phases.

[0168] <First Classification Process>

[0169] In the first classification step of this embodiment, the agglomerates obtained in the firing step are crushed and classified to obtain fired powder. The fired powder obtained in the firing step is usually agglomerated, so the agglomerates are pulverized for easier handling.

[0170] In the first classification step of this embodiment, the method for crushing the lumps is not particularly limited, and for example, a hammer or mortar can be used. Furthermore, the method for classifying the crushed lumps is also not particularly limited, and for example, a method of passing the crushed lumps through a sieve with a mesh size of 800 to 900 μm can be used.

[0171] <First Crushing Step>

[0172] 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, thereby further reducing the median particle size D of the phosphor powder. 50 .

[0173] In the first pulverization step of this embodiment, the method for pulverizing the calcined powder is not particularly limited. For example, a method of pulverizing the calcined powder to a predetermined particle size using a common pulverizer such as a ball mill, a vibration mill, or a jet mill can be listed. Among these, a jet mill is preferably used in the first pulverization step.

[0174] Annealing process

[0175] In the annealing step of this embodiment, the pulverized calcined powder obtained in the first pulverization step is annealed to obtain annealed powder. This removes strains and defects by rearranging elements, thereby further improving the luminescence characteristics of the phosphor powder.

[0176] The annealing process of this embodiment is preferably performed in a hydrogen atmosphere, an argon atmosphere, or a mixed atmosphere of hydrogen and argon, more preferably in an argon atmosphere. Furthermore, the annealing process of this embodiment is preferably performed under atmospheric pressure.

[0177] The heat treatment temperature in the annealing step of the present embodiment is preferably 1250°C or higher and 1450°C or lower, and more preferably 1300°C or higher and 1400°C or lower.

[0178] The heat treatment time in the annealing step of the present embodiment is preferably 6 hours to 10 hours, and more preferably 7 hours to 9 hours.

[0179] In the annealing step of this embodiment, similarly to the sintering step, the mixture is preferably filled into a container that is less reactive with the sintered powder (eg, a high melting point container, specifically, a container with an inner wall made of tungsten) and heated during heat treatment.

[0180] <Second Crushing Step>

[0181] 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 particle size D of the phosphor powder can be further reduced. 50 .

[0182] In the second pulverization step of this embodiment, the method for pulverizing the calcined powder is not particularly limited. For example, a method of pulverizing the calcined powder to a predetermined particle size using a common pulverizer such as a ball mill, a vibration mill, or a jet mill can be listed. Among these, a ball mill is preferably used in the second pulverization step.

[0183] From the perspective of further improving the performance balance of the obtained composite for small light-emitting devices, brightness and excitation light blocking properties, the crushing time in the second crushing step of this embodiment is preferably more than 10 hours and less than 30 hours, and more preferably more than 12 hours and less than 27 hours.

[0184] <Washing process>

[0185] In the elutriation step of this embodiment, the fine particles are removed from the pulverized annealed powder obtained in the second pulverization step by elutriation to obtain elutriated powder. This removes the fine particles that degrade the luminescence properties of the phosphor powder, thereby further improving the luminescence properties.

[0186] The elutriation process of this embodiment is performed by adding the crushed annealed powder to a dispersion medium to prepare a dispersion, stirring the mixture, allowing the annealed powder in the dispersion to settle, and removing the supernatant. After removing the supernatant, the precipitate is filtered and dried to obtain an elutriated powder from which fine particles have been removed. The elutriation process of this embodiment can be repeated to prepare the dispersion and remove the supernatant. In the elutriation process of this embodiment, an aqueous sodium hexametaphosphate solution is preferably used as the dispersion medium.

[0187] <Second Classification Process>

[0188] In the second classification step of this embodiment, the eluted powder obtained in the elution step is classified. This can further reduce the median particle size D of the phosphor powder. 50 .

[0189] In the second classification step of the present embodiment, the method of classifying the elutriated powder is not particularly limited, and an example thereof is a method of passing the elutriated powder through a sieve having a mesh size of 40 to 50 μm.

[0190] <Application>

[0191] The phosphor powder of this embodiment can be preferably used in small light-emitting devices, especially micro-LED displays, because the obtained composite has improved performance balance in applicability to small light-emitting devices, brightness, and excitation light blocking properties.

[0192] <Complex>

[0193] The composite body of this embodiment includes the phosphor powder of this embodiment and a sealing material that seals the phosphor powder. In the composite body of this embodiment, the phosphor powder of this embodiment is dispersed in the sealing material.

[0194] The phosphor powder of this embodiment has an improved performance balance in terms of applicability, brightness, and excitation light blocking performance of the obtained composite for small light-emitting devices. Therefore, the phosphor powder of this embodiment has an improved performance balance in terms of applicability, brightness, and excitation light blocking performance of the composite for small light-emitting devices.

[0195] In the composite of the present embodiment, the sealing material preferably includes one or two or more selected from the group consisting of silicone resin, epoxy resin, urethane resin, glass, and ceramics.

[0196] As a method for producing the composite of the present embodiment, there can be listed a method of adding the phosphor powder of the present embodiment to a liquid resin, glass, ceramic, etc., uniformly mixing, and then curing or sintering the mixture by heat treatment.

[0197] The composite of this embodiment can be formed into a sheet having a thickness of 100 μm or less. The median particle size D of the phosphor powder of this embodiment in the composite of this embodiment is 50 The particle size is 0.1 μm to 5.0 μm, which is moderately fine. Therefore, the phosphor powder in the sheet is uniformly dispersed, and the generation of aggregation is suppressed. Therefore, the composite of this embodiment can be preferably used in small light-emitting devices such as micro LED displays.

[0198] <Light-emitting device>

[0199] The light-emitting device of this embodiment includes a light-emitting element that emits excitation light and a complex of this embodiment that converts the wavelength of the excitation light.

[0200] Since the composite of this embodiment has improved applicability to small-sized light-emitting devices, and the performance balance between brightness and excitation light blocking property is improved, the performance balance between brightness and excitation light blocking property of the light-emitting device of this embodiment is improved.

[0201] Since the composite of this embodiment has improved applicability to small light-emitting devices, the performance balance of brightness and excitation light blocking ability is improved, especially when the light-emitting device of this embodiment is a small light-emitting device such as a micro LED display, the performance balance of brightness and excitation light blocking ability is also improved.

[0202] 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 a sheet preferably having a thickness of 100 μm or less, more preferably a thickness of 50 μm or less.

[0203] While the embodiments of the present invention have been described above, these are merely illustrative of the present invention, and various configurations other than those described above can be employed. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the objectives of the present invention are encompassed within the present invention.

[0204] Example

[0205] The embodiments of the present invention will be described in detail based on examples and comparative examples. However, the present invention is not limited to the examples.

[0206] (Example 1)

[0207] <Production of phosphor powder>

[0208] 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 Corporation, E grade) and 10.99 g of europium oxide (Eu2O3, manufactured by Shin-Etsu Chemical Co., Ltd.) were weighed into a container and pre-mixed.

[0209] Next, in a glove box maintained in a nitrogen atmosphere with a moisture concentration 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 Lab. Co., Ltd., purity 2N) were weighed into the container and dry-mixed. This produced a mixed powder. The details (mol ratio) of the charged amounts of each element in the mixed powder are shown in Table 1.

[0210] Inside a glove box, 230 g of the mixed powder was placed in a tungsten container. The container was closed and removed from the glove box. The container was then placed in an electric furnace equipped with a carbon heater. The furnace was then thoroughly evacuated until the pressure inside reached 0.1 PaG or less.

[0211] While continuing to vacuum evacuate, the temperature inside the electric furnace was raised to 600°C. After reaching 600°C, nitrogen was introduced into the furnace, and the pressure inside the furnace was adjusted to 0.85 MPaG. Then, under a nitrogen atmosphere, the temperature inside the electric furnace was raised to 1930°C. After reaching 1930°C, a heating treatment was performed for 4 hours. Heating was then terminated, and the furnace was cooled to room temperature. After cooling to room temperature, the agglomerates were recovered from the container.

[0212] The recovered lumps were crushed with a hammer, passed through a sieve with an opening of 850 μm, and then pulverized using a supersonic jet mill (PJM-80SP, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain calcined powder. The pulverization conditions were a sample feed rate of 100 g / min and a pulverization air pressure of 0.5 MPa.

[0213] The sintered powder obtained is filled in a tungsten container and quickly moved to an electric furnace equipped with a carbon heater. The vacuum is fully exhausted until the pressure in the furnace reaches 0.1 PaG or less. Heating is started while continuing to vacuum exhaust. When the temperature reaches 600°C, argon gas is introduced into the furnace to adjust the pressure of the furnace environment to atmospheric pressure. After the introduction of argon gas, the temperature is continued to rise to 1350°C. After the temperature reaches 1350°C, the heating treatment is carried out for 8 hours. Then, the heating is terminated and the furnace is cooled to room temperature. After cooling to room temperature, the annealed powder is recovered from the container.

[0214] The recovered powder was pulverized in a water solvent using zirconia balls in a ball mill for 26 hours to obtain an annealed powder.

[0215] The annealed powder was added to an aqueous sodium hexametaphosphate solution to prepare a dispersion, stirred, and then the annealed powder in the dispersion was allowed to settle, and the supernatant was removed. After the supernatant was removed, the precipitate was filtered and dried, and then passed through a 45 μm mesh to obtain an elutriated powder from which fine particles had been removed. This dispersion preparation and supernatant removal process was repeated five times.

[0216] In this way, the phosphor powder of Example 1 was obtained.

[0217] (Examples 2 to 5, Comparative Example 1)

[0218] 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 details (mol ratio) of the charged amounts of the elements in the mixed powder were changed.

[0219] (Example 6)

[0220] 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.

[0221] (Example 7, Comparative Example 2)

[0222] 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.

[0223] <X-ray diffraction spectrum>

[0224] Use wavelength The X-ray diffraction spectra of the phosphor powders of the embodiments and comparative examples were measured using an X-ray diffraction apparatus (Ultima IV manufactured by Rigaku Corporation) using CuKα rays (CuKα1) as a line source 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.

[0225] In the X-ray diffraction spectra obtained for each of the examples and comparative examples, the same diffraction pattern as that of the CaAlSiN 3 crystal was confirmed, and it was confirmed that the main crystalline phase had the same crystal structure as that of the CaAlSiN 3 crystal.

[0226] <Composition>

[0227] First, the phosphor powders from each Example and Comparative Example were dissolved by pressurized acid decomposition to prepare sample solutions. The resulting sample solutions were then subjected to quantitative elemental analysis using an ICP emission spectrometer (ICPE-9000, manufactured by Shimadzu Corporation). The molar ratios of Eu, Sr, Ca, Al, and Si contained in the phosphor powders from each Example and Comparative Example were determined. The results are shown in Table 1.

[0228] 0.03 g of the phosphor powder of each example and comparative example was weighed and the oxygen and nitrogen contents were measured using an oxygen / nitrogen analyzer (EMGA-920, manufactured by HORIBA, Ltd.) to determine the molar ratio of N to O. The results are shown in Table 1.

[0229] <Particle size>

[0230] The particle size distribution of the phosphor powder of each embodiment and each comparative example was measured by the following method using a particle size distribution measuring device (manufactured by MicrotracBEL Corp., MT3300EXII) using a laser diffraction scattering method. Specifically, about 30 mg of phosphor powder was added to 100 mL of a sodium hexametaphosphate aqueous solution with a concentration of 0.2%, and the powder was dispersed for 3 minutes using an Ultrasonic Homogenizer US-150E (manufactured by NIHONSEIKI KAISHA LTD., chip size φ20 mm, amplitude 100%, vibration frequency 19.5 KHz, amplitude of about 31 μm), and then measured using a particle size distribution measuring device. Based on the obtained particle size distribution, the median particle size D of the phosphor powder of each embodiment and each comparative example was calculated. 50 , the particle size D at which the cumulative value becomes 10% 10 , the particle size D at which the cumulative value reaches 90% 90 and (D 90 -D 10 ) / D 50 The results are shown in Table 1.

[0231] <Relative fluorescence intensity>

[0232] The relative fluorescence intensity of the phosphor powders used in each Example and Comparative Example was measured using a spectrofluorometer (F-7000, manufactured by Hitachi High-Technologies Corporation) calibrated with rhodamine B and a secondary standard light source. The fluorescence spectra were measured at an excitation wavelength of 455 nm using the solid sample holder included with the spectrofluorometer. The relative fluorescence intensity of the phosphor powders used in each Example and Comparative Example was then determined based on the peak intensities of the obtained fluorescence spectra. The results are shown in Table 1.

[0233] Here, relative fluorescence intensity was calculated by expressing the peak intensity of the fluorescence spectrum as relative peak intensity (%), with the peak height of the emission spectrum obtained by irradiating YAG:Ce (manufactured by Mitsubishi Chemical Corporation, P46Y3) with 455 nm monochromatic light set as 100%. In other words, relative fluorescence intensity is a value relative to a standard sample.

[0234] Absorbance, peak wavelength, and half-peak width

[0235] The phosphor powders of each Example and Comparative Example were filled into a concave groove to smooth the surface. After the concave groove was attached to the opening of an integrating sphere, monochromatic light with a wavelength of 455 nm, obtained 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 powders, and the fluorescence spectra of the phosphor powders of each Example and Comparative Example were measured using a spectrophotometer (MCPD-7000, manufactured by Otsuka Electronics Co., Ltd.).

[0236] The number of excitation reflected light photons (Qref) and the number of fluorescence photons (Qem) were calculated based on the data of the fluorescence spectra obtained for each embodiment and each comparative example. The number of excitation reflected light photons was calculated within the wavelength range of 450 to 465 nm, and the number of fluorescence photons was calculated within the range of 465 to 800 nm. In addition, using the same device, a standard reflector plate with a reflectivity of 99% (manufactured by Labsphere, Spectralon (registered trademark)) was installed at the opening of the integrating sphere, and the spectrum of the excitation light with a wavelength of 455 nm was measured. At this time, the number of excitation light photons (Qex) was calculated based on the spectrum in the wavelength range of 450 to 465 nm.

[0237] From the above calculation results, the absorptivity when the phosphor powders of each Example and each Comparative Example were irradiated with light having a wavelength of 455 nm was determined using the following calculation formula.

[0238] Absorption rate = ((Qex-Qref) / Qex) × 100

[0239] Furthermore, the peak wavelength and the half-value width of the peak were determined from the fluorescence spectra obtained for each of the Examples and Comparative Examples. The results are shown in Table 1.

[0240] In addition, the absorptivity, 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-mentioned measurement method. The results showed that the absorptivity was 74.4%, the peak wavelength was 543 nm, and the half-width was 53 nm.

[0241] Regarding the various measured values ​​of absorbance, peak wavelength and half-peak width, the values ​​may change if the manufacturer, manufacturing batch number, etc. of the measuring device are changed. Therefore, when measuring with a measuring device whose manufacturer, manufacturing batch number, etc. are different from those of the measuring device of this embodiment, the measured values ​​of the standard sample based on the above-mentioned β-sialon phosphor can be used as a reference to correct the various measured values.

[0242] <Diffuse reflectivity>

[0243] For each example and comparative example, the phosphor powder was measured using an ultraviolet-visible spectrophotometer (V-650, manufactured by JASCO Corporation) equipped with an integrating sphere (ISV-722, manufactured by JASCO Corporation). Baseline correction was performed using a standard reflector (Spectralon (registered trademark)). A solid sample holder filled with the phosphor powder was then set up. Diffuse reflectance was measured over a wavelength range of 450 to 800 nm to obtain diffuse reflectance spectra. The diffuse reflectance at a wavelength of 700 nm was then determined from the obtained diffuse reflectance spectra. The results are shown in Table 1.

[0244] <Sheet formability>

[0245] The phosphor powders of each Example and Comparative Example were mixed with a silicone resin (OE6630, manufactured by Dow Toray Co., Ltd.) in a mixer to a concentration of 40% by mass to produce a composite. The composite was then coated and cured at 150°C to form a 20 μm thick sheet. The sheet formability was evaluated according to the following criteria. The results are shown in Table 1.

[0246] A: No aggregation of phosphor powder occurs, and uniform sheets can be formed.

[0247] B: The phosphor powder aggregates and a uniform sheet cannot be formed.

[0248] <External quantum efficiency QE and excitation light transmittance T during sheet molding>

[0249] For the phosphor powder of each embodiment and each comparative example, the phosphor powder and the silicone resin (manufactured by Dow Toray Co., Ltd., OE6630) were mixed by a mixer in such a manner that the phosphor powder became 40% by mass to obtain a composite. Then, the composite was applied and cured at 150°C to obtain a sheet with a thickness of 20 μm. Then, the sheet was irradiated with light of a wavelength of 455 nm, and the luminescence spectrum of the light passing through the sheet was measured using a full-beam meter (manufactured by Otsuka Electronics Co., Ltd., HM series). Then, in the luminescence spectrum, the number of excitation transmitted light photons in the wavelength range of 401 to 492 nm was set as Qt, and the number of fluorescence photons in the wavelength range of 493 to 800 nm was set as Qem. Then, the luminescence spectrum of the 455 nm light used in the full-beam measurement was measured using the same device. Then, in the luminescence spectrum of the 455 nm light, the number of excitation light photons in the wavelength range of 401 to 492 nm was set as Qex. Next, the value of (Qem / Qex)×100 was determined and used as the external quantum efficiency QE during sheet formation. Furthermore, the value of (Qt / Qex)×100 was determined and used as the excitation light transmittance T. The results are shown in Table 1.

[0250] The charge ratios of the raw materials in each Example and each Comparative Example are shown in Table 1. The charge ratio is a molar ratio when Al is set to 1.000.

[0251] The compositions of the phosphor powders of Examples and Comparative Examples are shown in Table 1. The compositions are mol ratios when Al is set to 1.000.

[0252]

Claims

1. A phosphor powder comprising SCASN phosphor particles, wherein: The volume-based median particle size D of the phosphor powder based on the laser diffraction scattering method is 50 is 0.1 μm or more and 5.0 μm or less, When the phosphor powder 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, The absorptivity of the phosphor powder when irradiated with light having a wavelength of 455 nm is 80.0% or more.

2. The phosphor powder according to claim 1, wherein The SCASN phosphor particles contain a general formula of Eu a Sr b Ca c AlSi d N e O f Indicates phosphor particles with the following characteristics: 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 0.700＜b＜1.000。 5. The phosphor powder according to claim 2, wherein The molar ratio of b / (b+c) of the phosphor particles is greater than or equal to 0.800 and less than or equal to 0.

990.

6. The phosphor powder according to any one of claims 1 to 5, wherein In the volume frequency particle size distribution of the phosphor powder based on the laser diffraction scattering method, the particle size D at which the cumulative value becomes 10% is 10 It is 0.01 μm or more and 3.0 μm or less.

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

8. The phosphor powder according to any one of claims 1 to 5, wherein In the volume frequency particle size distribution of the phosphor powder by the laser diffraction scattering method, the particle size D at which the cumulative value becomes 10% is 10 , become 90% of the particle size D 90 , median particle size D 50 ,(D 90 -D 10 ) / D 50 The value is below 3.

00.

9. The phosphor powder according to any one of claims 1 to 5, wherein The half-value width of the peak of the fluorescence spectrum is 85.0 nm or less.

10. The phosphor powder according to any one of claims 1 to 5, wherein The diffuse reflectance at a wavelength of 700 nm measured by an ultraviolet-visible spectrophotometer is 80.0% or more.

11. The phosphor powder according to any one of claims 1 to 5, wherein The external quantum efficiency QE during sheet formation by the following method 1 is 47.5% or more. Method 1: The phosphor powder and the silicone resin are mixed by a mixer in such a manner that the phosphor powder becomes 40% by mass to obtain a composite; then, the composite is applied and cured at 150°C to obtain a sheet with a thickness of 20 μm; then, the sheet is irradiated with light of a wavelength of 455 nm, and the luminescence spectrum of the light passing through the sheet is measured using a full-beam meter; then, in the luminescence spectrum, the number of fluorescent photons in the wavelength range of 493 to 800 nm is set as Qem; then, the luminescence spectrum of the 455 nm light used in the full-beam measurement is measured using the same device; then, in the luminescence spectrum of the 455 nm light, the number of excitation light photons in the wavelength range of 401 to 492 nm is set as Qex; then, the value of (Qem / Qex)×100 is calculated and used as the external quantum efficiency QE when the sheet is formed.

12. The phosphor powder according to any one of claims 1 to 5, wherein The excitation light transmittance T based on the following method 2 is 11.0% or less, Method 2: The phosphor powder and the silicone resin are mixed by a mixer in such a manner that the phosphor powder becomes 40% by mass to obtain a composite; then, the composite is applied and cured at 150°C to obtain a sheet with a thickness of 20 μm; then, the sheet is irradiated with light of a wavelength of 455 nm, and the luminescence spectrum of the light passing through the sheet is measured using a full-beam meter; then, in the luminescence spectrum, the number of excitation transmitted light photons in the wavelength range of 401 to 492 nm is set as Qt; then, the luminescence spectrum of the 455 nm light used in the full-beam measurement is measured using the same device; then, in the luminescence spectrum of the 455 nm light, the number of excitation light photons in the wavelength range of 401 to 492 nm is set as Qex; then, the value of (Qt / Qex)×100 is calculated and used as the excitation light transmittance T. 13 . The phosphor powder according to claim 1 , which can be used in a micro-LED display. 14 . A composite comprising the phosphor powder according to claim 1 and a sealing material that seals the phosphor powder.

15. A light-emitting device comprising: a light-emitting element that emits excitation light; and The complex according to claim 14 converts the wavelength of the excitation light.

Images