Phosphors and light-emitting devices

Abstract

To provide a novel phosphor excellent in light emission intensity.SOLUTION: An aspect of the present disclosure provides a phosphor having the same crystal structure as Na5Al3F14 and represented by the general formula Na5-2xAl3F14:Eux, where the value of x satisfies 0.110≤x≤0.320.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to phosphors and light-emitting devices. [Background technology]

[0002] Phosphors are used in a variety of products, including vapor-fluorescent displays (VFDs), field emission displays (FRDs), surface-conduction electron-emitter displays, plasma display panels (PDPs), cathode-ray tubes (CRTs), liquid crystal display backlights, and light-emitting diodes (LEDs).

[0003] Various phosphors are known, including β-SiAlON and phosphors in which an activating element is solid-dissolved in nitrides such as CASN. In addition, Patent Document 1 describes Na5Al3F, which is called thiolite. 14 For Mn 4+ A red phosphor obtained by solid-solving [the substance] is disclosed. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2019-215451 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] As the applications of phosphors expand, there is a growing demand for new phosphors to broaden design options.

[0006] The present disclosure aims to provide a novel phosphor with excellent emission intensity. The present disclosure also aims to provide a light-emitting device including the above-described phosphor.

Means for Solving the Problems

[0007] The present disclosure provides the following [1] to [5].

[0008] [1] Na5Al3F 14 having the same crystal structure as, and having the general formula Na 5-2x Al3F 14 :Eu x a phosphor represented by, where the value of x satisfies 0.110 ≦ x ≦ 0.320. [2] The phosphor according to [1], where the value of x satisfies 0.130 ≦ x ≦ 0.253. [3] The phosphor according to [1] or [2], having an emission peak wavelength of 390 to 410 nm when irradiated with light having a wavelength of 365 nm. [4] The phosphor according to any one of [1] to [3], having a half-value width of the emission peak having the maximum emission intensity in the wavelength range of 390 to 410 nm in the emission spectrum when irradiated with light having a wavelength of 365 nm of 26.0 to 30.0 nm. [5] A light-emitting device including a light-emitting element that emits primary light, and a wavelength converter that absorbs a part of the primary light and emits secondary light having a wavelength longer than that of the primary light, where the wavelength converter contains the phosphor powder according to any one of [1] to [4].

Advantages of the Invention

[0009] According to the present disclosure, a novel phosphor with excellent emission intensity can be provided. According to the present disclosure, a light-emitting device including the above-described phosphor can also be provided.

Brief Description of the Drawings

[0010] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of a light-emitting device. [Figure 2] Figure 2 is an X-ray diffraction spectrum of the powder prepared in Example 3. [Figure 3] Figure 3 is an excitation-emission spectrum of the powder prepared in Example 3.

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present disclosure will be described. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following content.

[0012] Unless otherwise specified, the materials exemplified in this specification can be used alone or in combination of two or more. The content of each component in the composition means the total amount of the plurality of substances present in the composition when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified.

[0013] One embodiment of the phosphor has the same crystal structure as Na5Al3F 14 and has the general formula Na 5-2x Al3F 14 :Eu x It can also be said that the above phosphor is a compound in which a part of Na (sodium) in Na5Al3F 14 is replaced by Eu (europium). It can also be said that the present disclosure provides a phosphor powder which is an aggregate of the above phosphor particles and a phosphor composition combined with other phosphors. That the phosphor has the same crystal structure as Na5Al3F 14 can be confirmed by the diffraction pattern of the X-ray diffraction spectrum. More specifically, it can be determined by whether the phosphor to be measured exhibits a diffraction pattern similar to the diffraction pattern obtained by X-ray diffraction spectrum measurement for Na5Al3F 14 .

[0014] Na5Al3F 14This is a compound known as thiolite. Thiolite crystals belong to the tetragonal system and have the space group P4 / mnc symmetry. The space group of this crystal corresponds to number 128 in the International Tables for Crystallography. The above phosphor may, like thiolite, belong to the tetragonal system and have the space group P4 / mnc symmetry.

[0015] In this specification, the space group of a crystal is determined by comparing the diffraction pattern of the X-ray diffraction spectrum for the sample being measured with the diffraction pattern of a crystal group whose symmetry has been determined.

[0016] In the above phosphor, the general formula Na 5-2x Al3F 14 :EU x The value of x in this case is 0.110 ≤ x ≤ 0.320. Since sodium and europium have different valencies, it is assumed that defects will occur in the crystal structure when the above value of x is large and the amount of Eu solid solution is large. For this reason, it is presumed that the properties of the phosphor will deteriorate when the above value of x becomes large, for example, greater than 0.050. However, according to the inventors' studies, contrary to the above assumption, it was found that the luminescence intensity increases significantly when a certain amount of europium is solid-solved. This disclosure also incorporates these findings.

[0017] The lower limit of the above value of x may be, for example, 0.115 or higher, 0.120 or higher, 0.125 or higher, 0.130 or higher, 0.135 or higher, or 0.136 or higher. By having the lower limit of the above value of x within the above range, the phosphor can be made to have superior luminescence intensity. The upper limit of the above value of x may be, for example, 0.315 or less, 0.310 or less, 0.305 or less, 0.300 or less, 0.295 or less, 0.290 or less, 0.285 or less, 0.280 or less, 0.275 or less, 0.270 or less, 0.265 or less, 0.260 or less, 0.255 or less, 0.253 or less, 0.250 or less, 0.245 or less, 0.240 or less, 0.235 or less, 0.230 or less, 0.225 or less, 0.220 or less, 0.215 or less, 0.210 or less, 0.205 or less, or 0.200 or less. By keeping the lower limit of the above value of x within the above range, the effect of concentration quenching due to the increase in solid solubility of Eu can be further suppressed. The value of x above may be adjusted within the range described above, for example, 0.110≦x≦0.300, 0.130≦x≦0.253, 0.135≦x≦0.253, or 0.136≦x≦0.200.

[0018] The constituent elements and proportions of the phosphor can be determined by ICP emission spectroscopy using a multi-type ICP emission spectrometer. Fluorine (F), one of the constituent elements of the phosphor, can be determined by ion chromatography. Specifically, it is measured using the method described in the examples. Furthermore, since the elemental composition of the phosphor corresponds to the proportion of each element used in its manufacture, the elemental composition of the phosphor can also be estimated from the raw material composition.

[0019] The average particle size of the phosphor powder, which is an aggregate of the above-mentioned phosphor particles, may be, for example, 1 to 100 μm or 3 to 50 μm, and may be 5 to 35 μm when intended for use in LED packages. Having the average particle size of the phosphor powder within the above range is useful when preparing smaller light-emitting devices. Having the average particle size of the phosphor powder within the above range also makes it possible to further improve the luminescence brightness of the LED package when, for example, an LED package is prepared using the powder.

[0020] In this specification, the average particle size of the phosphor powder refers to the particle size (D50) at which the cumulative value from the smallest particle size reaches 50% of the total in the volume-based particle size distribution curve measured by laser diffraction and scattering. The particle size distribution curve for the phosphor powder is performed in accordance with the particle size distribution measurement method by laser diffraction and scattering described in JIS R 1629:1997 "Method for Measuring Particle Size Distribution of Fine Ceramics Raw Materials by Laser Diffraction and Scattering". A particle size distribution analyzer can be used for measurement. Specifically, first, 0.1 g of the phosphor powder to be measured is placed in 100 mL of deionized water, a small amount of sodium hexametaphosphate is added, and the mixture is dispersed using an ultrasonic homogenizer for 3 minutes to obtain the measurement sample. The particle size is then measured using a particle size distribution analyzer, and D50 is determined from the obtained particle size distribution. D50 is also called the median diameter. As a particle size distribution analyzer, for example, the "Microtrac MT3300EX II" (product name) manufactured by Microtrac-Bell Co., Ltd. can be used. As an ultrasonic homogenizer, for example, the "Ultrasonic Homogenizer US-150E" manufactured by Nippon Seiki Seisakusho Co., Ltd. (product name, tip size: φ20, Amplitude: 100%, oscillation frequency: 19.5KHz, amplitude: approximately 31μm) can be used.

[0021] The above-mentioned phosphor may have an emission peak wavelength of 390-410 nm when irradiated with light having a wavelength of 365 nm. In this specification, the emission peak wavelength of the above-mentioned phosphor means the peak wavelength of the emission peak having the maximum emission intensity in the wavelength range of 390-410 nm in the emission spectrum when irradiated with light having a wavelength of 365 nm.

[0022] The emission peak wavelength of the above phosphor when irradiated with light having a wavelength of 365 nm can be adjusted by the amount of solid solution of Eu. The emission peak wavelength of the above phosphor when irradiated with light having a wavelength of 365 nm can be, for example, 391 nm or higher, 392 nm or higher, 393 nm or higher, 394 nm or higher, or 395 nm or higher. The emission peak wavelength of the above phosphor when irradiated with light having a wavelength of 365 nm can be, for example, 408 nm or lower, 405 nm or lower, 400 nm or lower, or 398 nm or lower.

[0023] The above phosphor can have a small full width at half maximum (FWHM) of the emission peak having maximum emission intensity in the 390-410 nm wavelength range in its emission spectrum when irradiated with light of 365 nm. The above phosphor can have a FWHM of the emission peak having maximum emission intensity in the 390-410 nm wavelength range in its emission spectrum when irradiated with light of 365 nm, for example, 30.0 nm or less, 29.8 nm or less, 29.6 nm or less, or 29.4 nm or less. The above phosphor can have a FWHM of the emission peak having maximum emission intensity in the 390-410 nm wavelength range in its emission spectrum when irradiated with light of 365 nm, for example, 26.0 nm or more, 27.0 nm or more, 27.5 nm or more, 28.0 nm or more, or 28.5 nm or more. In the emission spectrum of the above-mentioned phosphor when irradiated with light of a wavelength of 365 nm, the full width at half maximum of the emission peak having the maximum emission intensity in the wavelength range of 390 to 410 nm can be within the range described above, for example, 26.0 to 30.0 nm, 27.0 to 29.8 nm, 27.0 to 29.6 nm, or 28.5 to 29.4 nm.

[0024] In this specification, the wavelength and full width at half maximum (FWHM) of the emission peak of a phosphor refer to values ​​determined by measuring the emission spectrum when irradiated with light of a wavelength of 365 nm. In this specification, FWHM refers to the full width at half maximum (FWHM), which can be determined from the emission spectrum obtained by measuring the emission spectrum when irradiated with light of a wavelength of 365 nm.

[0025] The upper limit of the chromaticity X of the above-mentioned phosphor powder may be, for example, 0.175 or less, 0.173 or less, or 0.172 or less. The chromaticity X of the above-mentioned phosphor powder may be, for example, 0.165 to 0.175, 0.167 to 0.174, or 0.170 to 0.172.

[0026] The lower limit of the chromaticity Y of the above-mentioned phosphor powder may be, for example, 0.020 or higher, 0.021 or higher, or 0.022 or higher. The chromaticity Y of the above-mentioned phosphor powder may be, for example, 0.020 to 0.037, 0.020 to 0.030, 0.020 to 0.023, or 0.020 to 0.022.

[0027] One example of a method for producing a phosphor involves calcining a raw material mixture containing sodium fluoride, aluminum fluoride, and europium fluoride.

[0028] In the raw material mixture, the proportions of sodium fluoride (NaF), aluminum fluoride (AlF3), and europium fluoride (e.g., EuF2, EuF3, etc.) are as follows: 5-2x Al3F 14 :EU x The value of x in the equation may be adjusted so that 0.110 ≤ x ≤ 0.320. This adjustment may be made, for example, by adjusting the ratio of the number of Al atoms to Eu atoms in the raw material mixture. That is, when the raw material mixture is expressed as Al:Eu=3:x, the Eu content may be adjusted so that 0.110 ≤ x ≤ 0.320.

[0029] The raw material mixture may contain other components in addition to sodium fluoride, aluminum fluoride, and europium fluoride. Examples of these other components include compounds that melt and form a liquid phase at or below the heating temperature in the calcination process. Such compounds function as fluxes, promoting the reaction of the raw material components and the growth of phosphor particles, thereby enabling the production of more stable phosphors. These compounds that can function as fluxes may be inorganic compounds, more specifically, sodium carbonate and magnesium fluoride.

[0030] The above raw material mixture can be prepared by weighing and mixing each compound. The mixing can be done using either a dry or wet mixing method. A dry mixing method may involve mixing each component using, for example, a V-type mixer. A wet mixing method may involve preparing a solution or slurry by adding a solvent or dispersion medium such as water, mixing the components, and then removing the solvent or dispersion medium.

[0031] The heating temperature (firing temperature) in the firing process may be, for example, 500 to 1200°C, 500 to 1000°C, 500 to 900°C, or 600 to 800°C. By keeping the lower limit of the firing temperature within the above range, the reaction can be further promoted. Furthermore, by keeping the upper limit of the firing temperature within the above range, the decomposition and volatilization of the raw material components can be further suppressed.

[0032] The heating time (firing time) in the firing process may be, for example, 1 to 96 hours, 1 to 80 hours, 1 to 60 hours, 1 to 30 hours, 2 to 15 hours, 2 to 12 hours, 2 to 10 hours, 2 to 8 hours, 2 to 6 hours, or 2 to 5 hours. The lower limit of the firing time being within the above range can further promote the reaction. The upper limit of the firing time being within the above range can further suppress the volatilization of raw material components.

[0033] The atmosphere during the firing process (firing atmosphere) may include, for example, air, nitrogen, hydrogen, argon, or a mixture of these gases. From the viewpoint of further improving the luminescence properties, the firing atmosphere may be a mixture of nitrogen and hydrogen, or a mixture of nitrogen and hydrogen in a volume ratio of N2:H2=96:4.

[0034] The above-described manufacturing method may include other steps in addition to the calcination step. Examples of other steps include a crushing step, a classification step, and an acid treatment step.

[0035] The crushing process involves crushing the calcined material, which may be obtained in a lumpy form during the calcination process, to adjust its particle size. A mortar and pestle may be used in the crushing process, or a general-purpose pulverizer or crusher may be employed. Examples of pulverizers and crushers include ball mills, jet mills, and Henschel mixers. The crushing process is preferably carried out using a wet ball mill with a medium such as deionized water. Zirconia balls can also be used in the ball mill.

[0036] The classification step may be a step to remove fine particles that reduce the luminescence brightness of the phosphor powder. When the required level of optical properties for the phosphor powder is high, it is desirable that the above-described method for producing the phosphor includes a classification step. The classification step may be performed by, for example, decantation. The classification step is carried out by putting the material to be processed (for example, phosphor powder that has undergone a crushing step) into a dispersion medium, preparing a dispersion, stirring it, allowing the phosphor powder in the dispersion to settle, and removing the supernatant. After removing the supernatant, the precipitate is recovered by filtration and dried to obtain phosphor powder from which fine particles have been removed. In the classification step, the above-described preparation of the dispersion and removal of the supernatant may be repeated. Examples of dispersion mediums include aqueous solutions of sodium hexametaphosphate.

[0037] The acid treatment step may be a step in which the phosphor powder is treated with an acid to reduce the content of impurities that do not contribute to luminescence. Examples of acids include hydrofluoric acid, sulfuric acid, phosphoric acid, hydrochloric acid, and nitric acid. The acid may contain at least one selected from the group consisting of hydrofluoric acid, sulfuric acid, phosphoric acid, hydrochloric acid, and nitric acid, and may be a mixed acid, but hydrochloric acid is preferred. The acid treatment step is carried out by bringing the phosphor powder into contact with the above-mentioned acid. Specifically, the above-mentioned phosphor powder is added to an aqueous solution containing the above-mentioned acid to prepare a dispersion, and the process is carried out for a predetermined time while stirring.

[0038] The phosphors described above may be used alone or in combination with other phosphors. Since the phosphors according to this disclosure can emit fluorescence with a peak in the ultraviolet region, they are useful as ultraviolet-emitting phosphors. Furthermore, since the phosphors according to this disclosure can exhibit excellent luminescence intensity, they are suitably used in light-emitting devices such as LEDs. The phosphors may also be dispersed in a curing resin. The curing resin is not particularly limited, and for example, resins used as sealing resins for light-emitting devices can be used. Examples of sealing resins include silicone resins, epoxy resins, polyvinyl resins, polyethylene, polypropylene, and polyester.

[0039] One embodiment of the light-emitting device comprises a light-emitting element that emits primary light, and a wavelength converter that absorbs a portion of the primary light and emits secondary light having a wavelength longer than the wavelength of the primary light. The wavelength converter contains the above-mentioned phosphor powder. The light-emitting element and the wavelength converter may be sealed with a sealing resin or the like.

[0040] Figure 1 is a schematic cross-sectional view showing an example of a light-emitting device. The light-emitting device shown in Figure 1 is an example of a surface-mount type optoelectronic device. The light-emitting device 100 comprises a substrate 10, a light-emitting element 40 electrically connected to a metal layer 20 provided on the surface of the substrate 10, a reflective portion 30 provided on the surface of the substrate 10 so as to surround the light-emitting element 40, and a transparent sealing resin 60 that fills the recess formed by the substrate 10 and the reflective portion 30 and seals the light-emitting element 40. A UV-emitting phosphor 52 and other phosphors 54 are dispersed in the transparent sealing resin 60. The UV-emitting phosphor 52 includes the phosphor according to this disclosure.

[0041] The substrate 10 has a metal layer 20 formed on a part of its surface, and the metal layer 20 serves as an electrode that is electrically connected to the light-emitting element 40 placed on the surface of the substrate 10. The light-emitting element 40 is die-bonded to either the anode side or the cathode side of the metal layer 20 and is electrically connected to the metal layer 20 via a die-bonding material 42. The light-emitting element 40 is also electrically connected to either the anode side or the cathode side of the metal layer 20 via a bonding wire 44.

[0042] The reflective section 30 is filled with a transparent sealing resin 60 for sealing the light-emitting element 40, and reflects the light (excitation light) emitted from the light-emitting element 40, as well as the fluorescence emitted from the ultraviolet-emitting phosphor 52 and other phosphors 54 in response to the above light, to the surface side of the light-emitting device 100.

[0043] The light-emitting element 40 may emit light (primary light, excitation light) capable of exciting the ultraviolet light-emitting phosphor 52 and other phosphors 54. The light-emitting element 40 may be, for example, a near-ultraviolet light-emitting diode (near-ultraviolet LED), an ultraviolet light-emitting diode (ultraviolet LED), and a blue light-emitting diode (blue LED). Multiple light-emitting elements 40 may be provided.

[0044] The light-emitting device 100 includes other phosphors 54 in addition to the ultraviolet-emitting phosphor 52, but may also consist of only the ultraviolet-emitting phosphor 52. The other phosphors 54 may include, for example, red phosphors, yellow phosphors, green phosphors, and blue phosphors.

[0045] In the above example, the light-emitting device was described using an example of an optoelectronic device classified as a surface-mount type, but it is not limited to this. The light-emitting device may be, for example, an analytical light source, a signaling device, or a backlight for liquid crystal displays and liquid crystal panels.

[0046] Although several embodiments have been described above, this disclosure is not limited in any way to the embodiments described above. Furthermore, the descriptions of the embodiments described above are applicable to each other. [Examples]

[0047] The contents of this disclosure will be described in more detail below with reference to examples and comparative examples. However, this disclosure is not limited to the following examples.

[0048] (Example 1) Sodium fluoride (NaF, manufactured by Sigma-Aldrich Japan LLC, model number: 201154) was measured out in an amount of 42.20 mass%, aluminum fluoride (AlF3, manufactured by High Purity Chemical Laboratory Co., Ltd., model number: ALH17PB) in an amount of 52.97 mass%, and europium fluoride (EuF3, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., model number: 053-05171) in an amount of 4.83 mass%, and these were measured out and mixed in an alumina mortar in air for 10 minutes to obtain the raw material mixture.

[0049] Next, the obtained raw material mixture was placed in an alumina crucible and heated in a high-temperature atmosphere furnace from room temperature to 700°C at a heating rate of approximately 5°C / min, and held at 700°C for 4 hours. The atmosphere in the high-temperature atmosphere furnace was a mixed gas of nitrogen and hydrogen (mixed so that the volume ratio of N2:H2 = 96:4; indicated as "N2 / 4vol%H2" in Table 1). After cooling to room temperature, the mixture was crushed in an alumina mortar, resulting in Na with dissolved Eu. 5-2x Al3F 14 :EU x A powder was prepared. Note that the obtained powder contains Na 5-2x Al3F 14 :EU x The powder was confirmed by the following compositional analysis. Confirmed Na 5-2x Al3F 14 :EU x We confirmed that the value of x in the formula shown matches the design composition. The value of x in the design composition is shown in Table 1.

[0050] [Compositional analysis: ICP emission spectrometry and ion chromatography] The composition was analyzed using a multi-type ICP emission spectrometer (Agilent, model number: 5110VDV). 10 mg of the powder to be measured was placed in a platinum crucible, 2 g of alkaline flux was added, and it was melted in an electric furnace. After cooling, 20 mL of hydrochloric acid (HCl) was added to the platinum crucible, and the mixture was heated and dissolved in a warm bath to obtain a solution. The obtained solution was then diluted to a final volume of 100 mL. This 100 mL solution was diluted 10-fold with pure water to prepare the test solution, which was then set in the above-mentioned instrument and its composition was analyzed.

[0051] The fluorine (F) content of the phosphor was measured using ion chromatography / IC (DIONEX, model number: DX-320). 50 mL of water was placed in a plastic container and transferred to a 50°C constant temperature bath. After confirming that the water reached 50°C, 0.5 g of the phosphor sample (the powder mentioned above) was added and stirred for 10 minutes. After stirring, solid matter was removed using a 0.45 μm membrane filter, and only the aqueous solution was extracted. The solution was diluted according to the calibration curve concentration, and ion chromatography measurements were performed to determine the proportion of fluorine. The measurement conditions were as follows. • Measurement column: Ion PacAG22 / AS22 ·Eluent: Na2CO34.5mmol / L, NaHCO34.0mmol / L ·Eluent flow rate: 1 / 2 ml / L ·Thermostat temperature: 35℃ • Suppressor-equipped electrical conductivity (detector): 50mA • Sample introduction volume: 50 μL

[0052] (Examples 2-5, Comparative Examples 1-3) General formula Na 5-2x Al3F 14 :EU x Except for changing the value of x in the following way as shown in Table 1 and adjusting the mixing amount of each component, the process was the same as in Example 1, with Na containing Eu in solid solution. 5-2x Al3F 14 :EU x A powder was prepared.

[0053] <Na 5-2x Al3F 14 :EUx Evaluation of the luminescence properties of the powder > The powders prepared in the above-described examples and comparative examples were evaluated for their crystal structure, relative emission intensity, emission peak wavelength, full width at half maximum, chromaticity X, and chromaticity Y using the method described later.

[0054] [Confirmation of crystal structure] The crystal structure of the powder prepared in the example was confirmed. First, the X-ray diffraction spectrum obtained in the example was acquired. The obtained diffraction pattern was Na5Al3F 14 By comparing it with the X-ray diffraction pattern, the powder obtained in the example was found to be Na5Al3F 14 It was confirmed that it has the same crystal structure as [the other material]. For the measurement, "Ultima IV" (product name) manufactured by Rigaku Corporation was used, and the measurement range was set to 10 to 120°. For reference, Figure 2 shows the X-ray diffraction spectrum of the powder prepared in Example 3.

[0055] [Measurement of emission intensity, determination of emission peak wavelength and full width at half maximum] To confirm whether the powders prepared in the examples and comparative examples function as phosphors, their emission intensity was measured. First, the phosphor to be measured was packed into a quartz cell and fixed in the attached fixed sample holder. Next, the emission spectrum was measured using light with a wavelength of 365 nm as the excitation light. When measuring the excitation spectrum, the fluorescence monitor wavelength was set to 393 nm. In addition, the emission peak wavelength was determined from the obtained emission spectrum, and the wavelength at which the intensity value of half the maximum emission intensity of the emission peak was determined was determined, and the half-width was calculated by taking the difference. A spectrofluorometer "F-7000" (product name) manufactured by Hitachi High-Tech Science Corporation was used for the measurement. The results are shown in Table 1. In Table 1, the relative emission intensity is shown as a relative value with the emission intensity of the powder (phosphor) prepared in Example 1 set to 100. For reference, the excitation and emission spectra of the powder prepared in Example 3 are shown in Figure 3. In Figure 3, the excitation spectrum is shown by a dotted line, and the emission spectrum is shown by a solid line.

[0056] [Chromaticity X and chromaticity Y] Chromaticity X and Y were determined by calculating the x-value (chromaticity X) and y-value (chromaticity Y) of the CIE chromaticity coordinate in the XYZ color system as defined in JIS Z 8781-3:2016 "Colorimetry - Part 3: CIE Tristimulus Values" from spectral data in the wavelength range of 375 to 800 nm of the emission spectrum, in accordance with JIS Z 8724:2015 "Methods for measuring color - Light source color". The spectral data for measuring chromaticity X and Y were measured as follows.

[0057] First, the phosphor to be measured (the powder prepared in the above-described examples and comparative examples) was packed into a concave cell so that its surface was smooth, and then attached to the opening of an integrating sphere. Monochromatic light spectrally separated to a wavelength of 365 nm from a Xe lamp, which was the light source, was introduced into the integrating sphere as excitation light for the phosphor using an optical fiber. This monochromatic excitation light was irradiated onto the phosphor to be measured, and the emission spectrum was measured to acquire spectral data. A spectrophotometer (Otsuka Electronics Co., Ltd., "MCPD-7000" (product name)) was used for the measurement.

[0058] [Table 1] [Industrial applicability]

[0059] This disclosure provides a novel phosphor with excellent luminescence intensity. The phosphor according to this disclosure is useful as an ultraviolet-emitting phosphor and can be used, for example, as a light source for analytical instruments. This disclosure also provides a light-emitting device equipped with the above-mentioned phosphor. [Explanation of Symbols]

[0060] 10...Substrate, 20...Metal layer, 30...Reflective part, 40...Light-emitting element, 42...Die bond material, 44...Bonding wire, 52...UV-emitting phosphor, 54...Other phosphors, 60...Transparent sealing resin, 100...Light-emitting device.

Claims

1. Na ５ Al ３ F １４ It has the same crystal structure as, and its general formula is Na ５－２ｘ Al ３ F １４ :Eu ｘ A phosphor represented by, A phosphor in which the value of x is 0.110 ≤ x ≤ 0.

320.

2. The phosphor according to claim 1, wherein the value of x is 0.130 ≤ x ≤ 0.

253.

3. The phosphor according to claim 1 or 2, wherein the emission peak wavelength when irradiated with light having a wavelength of 365 nm is 390 to 410 nm.

4. The phosphor according to claim 1 or 2, wherein, in the emission spectrum when irradiated with light of a wavelength of 365 nm, the full width at half maximum of the emission peak having the maximum emission intensity in the wavelength range of 390 to 410 nm is 26.0 to 30.0 nm.

5. A light-emitting device comprising a light-emitting element that emits primary light, and a wavelength converter that absorbs a portion of the primary light and emits secondary light having a wavelength longer than the wavelength of the primary light, A light-emitting device comprising the wavelength converter containing the phosphor powder described in claim 1 or 2.

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