Phosphor, its manufacturing method, and light-emitting device

Abstract

Provided are: an inorganic fluorescent body that has luminescence in a violet color range of 380-410 nm, and that has a spectrum in which the half width of the luminescence is 40 nm or less; a method for producing same; and a light-emitting device thereof. In an example of the present invention, a fluorescent body contains an inorganic compound containing at least sodium (Na), aluminum (Al), fluorine (F), and europium (Eu). The inorganic compound at least includes Eu in a Na5Al3F14 crystal or in a crystal having the same crystal structure as Na5Al3F14.

Description

[Technical Field]

[0001] The present invention is based on Na5Al3F 14 and a phosphor containing Eu in a crystal represented by the formula (I) and a crystal having the same crystal structure as the phosphor, a method for producing the same, and a light-emitting device. [Background technology]

[0002] Phosphors are used in vacuum fluorescent displays (VFDs), field emission displays (FEDs or SEDs), plasma display panels (PDPs), cathode ray tubes (CRTs), liquid crystal display backlights, and white light-emitting diodes (LEDs). In any of these applications, energy must be supplied to the phosphors to excite them. Phosphors are excited by high-energy excitation sources such as vacuum ultraviolet light, ultraviolet light, electron beams, and blue light to emit visible light such as blue, green, yellow, orange, and red.

[0003] Many phosphors have been reported so far (see, for example, Patent Documents 1 to 6). Patent Document 1 discloses an orange-emitting sialon phosphor containing alkaline earth elements. As another example, Patent Document 2 discloses a β-type sialon phosphor containing Eu 2+ Patent Document 3 discloses a green phosphor activated by . It is known that in this phosphor, the emission wavelength can be shifted to a shorter wavelength by changing the oxygen content while maintaining the crystal structure. Furthermore, Patent Document 4 discloses an example of an oxynitride phosphor, which is a JEM phase (LaAl(Si 6-z Al z )N 10-z O zA blue phosphor is known in which Ce is activated by using a La-N crystal (La3Si8N) as a host crystal. In this phosphor, it is known that by substituting part of the La with Ca while maintaining the crystal structure, the excitation wavelength and the emission wavelength are lengthened. Furthermore, according to Patent Document 5, another example of an oxynitride phosphor is a La-N crystal, La3Si8N 11 A blue phosphor is known that uses O4 as a host crystal and Ce as an activation agent.

[0004] Na5Al3F 14 is a crystal known as thiolite, and according to Patent Document 6, Mn 4+ The phosphors doped with thiolite are known as red phosphors. Furthermore, thiolite itself is almost colorless and transparent, and is said to be snow-white. It has a glassy luster and a specific gravity of 2.998.

[0005] Thus, the color of light emitted by a phosphor is determined by the combination of the host crystal and the metal ions (activator ions) dissolved in it. Furthermore, the combination of the host crystal and activator ions determines the luminescence characteristics such as the emission spectrum and excitation spectrum, as well as the chemical stability and thermal stability, so if the host crystal or activator ions are different, they are considered to be different phosphors. Furthermore, materials with the same chemical composition but different crystal structures are considered to be different phosphors because the luminescence characteristics and stability differ due to the different host crystals. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-363554 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-255895 [Patent Document 3] International Publication No. 2007 / 066733 [Patent Document 4] International Publication No. 2005 / 019376 [Patent Document 5] Japanese Patent Application Laid-Open No. 2005-112922 [Patent Document 6] Japanese Patent Application Publication No. 2019-215451 Summary of the Invention [Problem to be solved by the invention]

[0007] In embodiments of the present invention, a novel phosphor having specific emission characteristics can be provided. The phosphor may have emission characteristics (emission color, excitation characteristics, emission spectrum) different from those of conventional phosphors. In particular, an inorganic phosphor that emits light in the purple region from 380 nm to 410 nm and has an emission spectrum with a half-width of 40 nm or less, and a method for producing the same can be provided. In embodiments of the present invention, a light-emitting device using such a phosphor and having excellent durability can be provided. [Means for solving the problem]

[0008] Under these circumstances, the present inventors have conducted detailed research into phosphors based on fluorine-containing crystals, and have discovered Na5Al3F 14 crystal (hereinafter referred to as this crystal) and Na5Al3F 14 We have found that an inorganic material in which Eu is added to a host crystal having the same crystal structure as the crystal (hereinafter referred to as the "identical crystal") emits highly bright fluorescence. We have also found that a specific composition exhibits purple emission. Furthermore, we have found that the use of this phosphor can produce colored or white light-emitting diode devices containing spectral components with narrow half-widths, as well as lighting fixtures and image display devices using such devices.

[0009] In an embodiment of the present invention, the phosphor comprises an inorganic compound containing at least sodium (Na), aluminum (Al), fluorine (F), and europium (Eu), and the inorganic compound is Na5Al3F 14 Crystal or Na5Al3F 14 The crystal may contain at least Eu in a crystal having the same crystal structure as that of the above. The inorganic compound contains at least sodium (Na), aluminum (Al), fluorine (F), and europium (Eu), and the inorganic compound contains at least Eu, such as Na5Al3F 14 Crystals or the Na5Al3F 14 The phosphor may include crystals having the same crystal structure as the crystal. The inorganic compound may further contain oxygen. When the ratio of the number of Al atoms to the number of Eu atoms contained in the inorganic compound is expressed as Al:Eu=3:x, the value of x may satisfy the range of 0.0125≦x≦0.1. The value of x may satisfy the range of 0.025≦x≦0.05. The inorganic compound is (Na,Eu,□)5Al3(O,F) 14 (where □ represents an atomic deficiency). The inorganic compound further contains magnesium (Mg), and the inorganic compound is (Na,Eu)5(Al,Mg)3F 14 The composition may be expressed as follows: The inorganic compound is Na 5-x EU x Al3F 14+x (wherein 0.025≦x≦0.05) The inorganic compound is Na 5-2x EU x Al3F 14 (wherein 0.025≦x≦0.05) Any of the above phosphors may emit fluorescence having a peak in the wavelength range of 380 nm or more and 410 nm or less when irradiated with light in the wavelength range of 250 nm or more and less than 380 nm. Any of the above phosphors may emit fluorescence having a spectral shape with a half width of 20 nm or more and 40 nm or less when irradiated with light in the wavelength range of 250 nm or more and less than 380 nm. In an embodiment of the present invention, any of the above-mentioned methods for producing a phosphor may include mixing raw materials containing at least sodium fluoride, europium fluoride, and aluminum fluoride, and reacting the raw materials at a temperature in the range of 500°C to 1200°C. In an embodiment of the present invention, the light-emitting device comprises at least a luminescent source and a phosphor, the luminescent source emitting light in a wavelength range of 250 nm or more and less than 380 nm, and the phosphor may include any of the above phosphors. In any of the above light-emitting devices, the phosphor may further include a blue phosphor having a peak emission wavelength in the range of 440 nm or more and 500 nm or less, a green phosphor having a peak emission wavelength in the range of 500 nm or more and 580 nm or less, and a red phosphor having a peak emission wavelength in the range of 600 nm or more and 700 nm or less. [Effects of the Invention]

[0010] In an embodiment of the present invention, a phosphor may contain the present crystal or the same crystal as a main component. It exhibits higher luminescence brightness than conventional oxide phosphors and oxynitride phosphors, and in certain compositions, it is excellent as a purple phosphor. It may also have a narrow half-width of the emission spectrum. Even when exposed to an excitation source, this phosphor is resistant to a decrease in luminance, providing a useful phosphor that can be suitably used in light-emitting devices such as white light-emitting diodes, lighting fixtures, backlight sources for liquid crystal displays, infrared luminaires, and infrared light sources for inspection. [Brief explanation of the drawings]

[0011] [Figure 1] A schematic diagram of the crystal structure of Na5Al3F14 crystal is shown. [Figure 2] 1 shows a schematic diagram of the powder X-ray pattern (CuKα1) of Example 3. [Figure 3] 1 shows a schematic diagram of the powder X-ray pattern (CuKα1) of Example 7. [Figure 4] FIG. 1 shows the excitation and emission spectra of the product of Example 1. [Figure 5] FIG. 10 is a schematic diagram showing a lighting fixture (bullet-shaped LED lighting fixture) according to Example 9. [Figure 6] FIG. 13 is a schematic diagram showing a lighting fixture (board-mounted LED lighting fixture) according to Example 10. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be explained in detail below in the examples. In an embodiment of the present invention, the phosphor contains an inorganic compound containing at least sodium (Na), aluminum (Al), fluorine (F), and europium (Eu). Such an inorganic compound is Na5Al3F 14 Crystal (original crystal), or Na5Al3F 14 The inorganic compound contains at least Eu in a crystal having the same crystal structure as the present crystal (the present identical crystal). Specifically, the inorganic compound has the present crystal or the present identical crystal as a host crystal, and Eu is contained in the host crystal. 2+ The present inventors have investigated the crystal or the same crystal and Eu 2+ We discovered that by combining this crystal with Eu, a phosphor that emits purple fluorescence due to the influence of the crystal field was obtained. 2+ To the best of the inventors' knowledge, this combination of phosphors has not been reported prior to the filing of the present application.

[0013] Na5Al3F 14 The crystal is known as thiolite, as mentioned above. Thiolite is a substance that belongs to the tetragonal crystal system, the P4 / mnc space group (number 128 in the International Tables for Crystallography), and is characterized by the lattice constants (a=7.014 Å, b=7.014 Å, c=10.402 Å). In the examples of the present invention, this crystal (see, for example, FIG. 1) and this identical crystal can be identified by X-ray diffraction or neutron diffraction. This identical crystal is Na5Al3F 14 In a crystal, the lattice constant and atomic positions change due to the substitution of constituent elements with other elements, but the atomic positions given by the crystal structure, the sites occupied by the atoms, and their coordinates do not change so much that the chemical bonds between the skeletal atoms are broken.

[0014] In this specification, when the ten major diffraction peaks (2θ) with the strongest diffraction intensity among the X-ray diffraction results measured for the target substance match the diffraction data obtained by calculation (ICDD04-010-1794), the target substance is identified as this crystal or this identical crystal.

[0015] The inorganic compound may contain oxygen (O). In this case, the present crystal or the present identical crystal further contains oxygen (O), and part of the F in the crystal is replaced with oxygen, thereby replacing Na in the crystal with Eu. 2+ When substituted with , the charge can be easily kept neutral, stabilizing the crystal and increasing the emission intensity.

[0016] Eu added to the crystal 2+ The concentration of affects the luminescence characteristics. When the ratio of the number of Al and Eu atoms contained in an inorganic compound is expressed as Al:Eu=3:x, a phosphor with an Eu content (x) of 0.0125≦x≦0.1 has high luminescence intensity. If it is less than 0.0125, the amount of Eu is too small, which may result in a decrease in luminescence intensity. If it exceeds 0.1, the distance between Eu atoms contained in the crystal becomes short, which may lead to energy dissipation due to concentration quenching, resulting in a decrease in luminescence intensity. More preferably, x satisfies the range of 0.025≦x≦0.05. This increases the luminescence intensity.

[0017] The inorganic compound is preferably (Na,Eu,□)5Al3(O,F) 14 (where □ indicates atomic deficiency). Here, in the examples of the present invention, Na and Eu are always included. Phosphors containing such inorganic compounds tend to maintain charge neutrality, resulting in a stabilized crystal structure and high emission intensity. Na5Al3F 14 When Eu is added to a crystal, Eu tends to occupy the Na site in the crystal. Since Na tends to be monovalent and Eu tends to be divalent, in order to match the overall charge, a composition can be selected in which two Na atoms are substituted with one Eu atom. Alternatively, the charges can be matched by substituting one Na atom with one Eu atom and simultaneously substituting one F atom with one oxygen atom.

[0018] The inorganic compound further contains magnesium (Mg), and may be represented by (Na,Eu)5(Al,Mg)3F 14 Here, in the examples of the present invention, Na and Eu are always included (0 < Na < 5 and 0 < Eu < 5). A phosphor containing such an inorganic compound is likely to maintain charge neutrality, so the crystal structure is stabilized and the emission intensity increases. When Eu and Mg are added to the Na5Al3F 14 crystal, Eu is likely to enter the Na position in the crystal, and Mg is likely to enter the Al position in the crystal. Na is likely to have a valence of 1, Eu is likely to have a valence of 2, Al is likely to have a valence of 3, and Mg is likely to have a valence of 2. By substituting one Na with one Eu and simultaneously substituting one Al with one Mg, the charges can be balanced.

[0019] The inorganic compound is preferably Na 5-x Eu x Al3F 14+x (where 0.025 ≦ x ≦ 0.05). A phosphor containing such an inorganic compound is likely to maintain charge neutrality, so the crystal structure is stabilized and the emission intensity increases. When Eu is added to the Na5Al3F 14 crystal, Eu is likely to enter the Na position in the crystal. Na is likely to have a valence of 1 and Eu is likely to have a valence of 2. By substituting one Na with one Eu and simultaneously allowing one F to enter the interstices of the crystal lattice, the charges can be balanced.

[0020] The inorganic compound is preferably Na 5-2x Eu x Al3F 14 (where 0.025 ≦ x ≦ 0.05). A phosphor containing such an inorganic compound is likely to maintain charge neutrality, so the crystal structure is stabilized and the emission intensity increases. In this case, Na5Al3F 14Two Na atoms in the crystal are replaced with one Eu atom, leaving one atomic deficiency at the Na site, maintaining charge neutrality. If the value of x is less than 0.025, the amount of Eu responsible for luminescence is small, which may result in low luminescence intensity. If the value of x is greater than 0.05, the luminescence intensity may be low due to concentration quenching. For example, in Figure 1, Eu may occupy some of the Na sites. Also, O may occupy some of the F sites.

[0021] In an embodiment of the present invention, the phosphor has a specific composition, and when irradiated with light having a wavelength range of 250 nm or more and less than 380 nm, the phosphor preferably has a peak (maximum value of the peak) in the wavelength range of 380 nm or more and 410 nm or less. In an embodiment of the present invention, the phosphor more preferably has a peak in the wavelength range of 385 nm or more and 400 nm or less when irradiated with light having a wavelength range of 250 nm or more and less than 380 nm, a typical peak being 393 nm. This allows for a spectrum suitable for purple light emission applications.

[0022] In addition, in an embodiment of the present invention, the phosphor has a specific composition, and thereby preferably emits fluorescence having a spectral shape with a half-width in the range of 20 nm to 40 nm, and more preferably emits fluorescence having a spectral shape with a half-width in the range of 25 nm to 35 nm.

[0023] In this embodiment of the present invention, the method for producing the phosphor need not be particularly specified. For example, the phosphor can be obtained by mixing raw materials containing sodium fluoride, europium fluoride, and aluminum fluoride and firing them at a temperature in the range of 500°C to 1200°C. If the temperature is lower than 500°C, the reaction may not proceed sufficiently. If the temperature exceeds 1200°C, the raw material powder and the compound may decompose. The firing atmosphere may be air, nitrogen, nitrogen-hydrogen, argon, or the like. The firing time varies depending on the firing temperature, but is usually preferably about 1 hour to 96 hours.

[0024] The average particle size of the phosphor powder is preferably 50 nm or more and 200 μm or less in volume median diameter (d50) because this results in high luminescence intensity. The volume average particle size can be measured, for example, by a microtrack or laser scattering method. The average particle size of the phosphor powder synthesized by firing can be adjusted to 50 nm or more and 200 μm or less by using one or more methods selected from pulverization, classification, and acid treatment.

[0025] During firing to synthesize a phosphor, adding an inorganic substance that forms a liquid phase at temperatures below the firing temperature can act as a flux, promoting reaction and grain growth and resulting in stable crystals, which can improve luminescence intensity.

[0026] Furthermore, by washing with a solvent after firing, the content of inorganic substances that form a liquid phase at temperatures below the firing temperature can be reduced, which can increase the luminescence intensity of the phosphor.

[0027] In the examples of the present invention, when the phosphor is used for applications such as a light emitting device, it is preferable to use it in a form in which it is dispersed in a liquid medium. Also, in the examples of the present invention, it can be used as a phosphor mixture containing the phosphor. In the examples of the present invention, a phosphor dispersed in a medium is referred to as a phosphor-containing composition.

[0028] In the examples of the present invention, any medium that can be used in the phosphor-containing composition can be selected depending on the purpose, etc., as long as it can suitably disperse the phosphor as in the examples of the present invention and does not cause undesirable reactions, etc. Examples of the medium include glass, silicone resin, epoxy resin, polyvinyl resin, polyethylene resin, polypropylene resin, polyester resin, etc. These media may be used alone, or two or more may be used in any combination and ratio.

[0029] In an embodiment of the present invention, a light-emitting device can be constructed by combining a phosphor with a light source (excitation source). Examples of light-emitting sources include light-emitting diodes (LEDs), laser diodes (LDs), organic electroluminescent (EL) light-emitting devices, and fluorescent lamps. In an embodiment of the present invention, LEDs can be manufactured using phosphors by known methods such as those described in Japanese Patent Application Laid-Open Nos. 5-152609, 7-99345, and Japanese Patent Publication No. 2927279. In this case, the light-emitting body or light source used emits light in the wavelength range of 250 nm or more and less than 380 nm. These LEDs include those made of semiconductors such as GaN, InGaN, and AlN, and by adjusting their composition, they can become light sources that emit light of a predetermined wavelength.

[0030] In an embodiment of the present invention, in addition to the phosphors as in the embodiment of the present invention, one form of light-emitting device can further include a blue phosphor having a peak emission wavelength in the range of 440 nm to 500 nm, a green phosphor having a peak emission wavelength in the range of 500 nm to 580 nm, and a red phosphor having a peak emission wavelength in the range of 600 nm to 700 nm. This allows the embodiment of the present invention to become a light-emitting device containing blue, green, and red color components in addition to the light emitted from the phosphors (purple).

[0031] In an embodiment of the present invention, in addition to the phosphors as in the embodiment of the present invention, one form of light-emitting device can further include a blue phosphor having an emission peak wavelength in the range of more than 410 nm and not more than 500 nm, a green phosphor having an emission peak wavelength in the range of more than 500 nm and not more than 580 nm, and an orange to red phosphor having an emission peak wavelength in the range of more than 580 nm and not more than 700 nm. This allows the embodiment of the present invention to become a light-emitting device containing blue, green, and orange to red color components in addition to the emission (purple) from the phosphors.

[0032] Examples of such blue phosphors include AlN:(Eu,Si), BaMgAl 10 O 17 :Eu, SrSi9Al 19 ON31 :Eu, LaSi9Al 19 N 32 :Eu, α-sialon:Ce, JEM:Ce, etc.

[0033] Examples of such green phosphors include β-sialon:Eu, (Ba, Sr, Ca, Mg) 2 SiO 4 :Eu, and (Ca, Sr, Ba) Si 2 O 2 N 2 :Eu.

[0034] Such red phosphors include CaAlSiN3:Eu, (Ca,Sr)AlSiN3:Eu, Ca2Si5N8:Eu, and Sr2Si5N8:Eu. [Example]

[0035] The present invention will be described in more detail with reference to the following specific examples. These examples are merely provided to aid in the understanding of the present invention, and the present invention is not limited to these examples.

[0036] [Raw materials used in synthesis] The raw material powders used in the synthesis were sodium fluoride (Sigma-Aldrich Japan, LLC, product number 201154), europium fluoride (Fujifilm Wako Pure Chemical Industries, Ltd., product number 053-05171), europium oxide (Shin-Etsu Chemical Co., Ltd., product number EU-03-129), aluminum fluoride (Kojundo Chemical Laboratory Co., Ltd., product number ALH17PB), aluminum oxide (Taimei Chemical Industry Co., Ltd., product number TM-DAR), and magnesium fluoride (Fujifilm Wako Pure Chemical Industries, Ltd., product number 137-09101).

[0037] [Phosphor Examples: Examples 1 to 8] In Examples 1 to 8, raw material powders were mixed so that the ratio of metal atoms satisfied the composition shown in Table 1, and phosphors were synthesized.

[0038] Specifically, in Examples 1 to 4, sodium fluoride powder, europium fluoride powder, and aluminum fluoride powder were weighed and mixed in air so that Na:Eu:Al=5-2x:x:3 (x=0.05, 0.0125, 0.025, 0.1), respectively. The mixed powder was loaded onto an alumina boat and fired at 700°C for 4 hours in a mixed gas stream containing 5% by volume of hydrogen gas and the remainder being nitrogen.

[0039] In Example 5, synthesis was carried out in the same manner as in Examples 1 to 4, except that sodium fluoride powder, aluminum fluoride powder, and europium oxide powder were weighed out so that Na:Eu:Al=4.975:0.025:3.

[0040] In Example 6, synthesis was carried out in the same manner as in Examples 1 to 4, except that sodium fluoride powder, europium fluoride powder, aluminum fluoride powder, and aluminum oxide powder were weighed out so that Na:Eu:Al=4.975:0.025:3.

[0041] Here, aluminum oxide was used to offset the excess positive charge (0.025) generated by Eu doping. The amounts of aluminum fluoride powder and aluminum oxide powder were set as follows: The Al (AlO1.5 equivalent) in aluminum oxide (Al2O3) was 0.01667 (≒0.025 / 1.5), and the remaining Al component was aluminum fluoride (AlF3) at 2.98333 (=3 - 0.01667), for a total Al content of 3.

[0042] In Example 7, synthesis was carried out in the same manner as in Examples 1 to 4, except that sodium fluoride powder, europium fluoride powder, aluminum fluoride powder, and magnesium fluoride powder were weighed out so that the ratio of Na:Eu:Al:Mg was 4.975:0.025:2.975:0.025.

[0043] In Example 8, synthesis was carried out in the same manner as in Examples 1 to 4, except that sodium fluoride powder, europium fluoride powder, and aluminum fluoride powder were weighed out so that Na:Eu:Al=4.975:0.025:3.

[0044] [Table 1]

[0045] The product phases of the products of Examples 1 to 8 were identified using powder X-ray diffraction. The results are shown in Table 2. The emission spectra of the products of Examples 1 to 8 were measured using a spectrofluorometer (FP8600, manufactured by JASCO Corporation). The results are shown in FIG. 4 and Table 3. The above results will be summarized.

[0046] [Table 2]

[0047] The powder X-ray diffraction patterns of the products of Examples 1 to 8 were Na5Al3F 14 The crystal pattern of the crystal (ICDD04-010-1794) was in good agreement with that of the crystal. For example, the powder X-ray diffraction patterns of Examples 3 and 7 are shown in Figures 2 and 3, respectively. From this, it can be seen that the product phases of Examples 1 to 8 were Na5Al3F 14 Crystal or Na5Al3F 14 It was found that the crystal structure was the same as that of the Na5Al3F crystal. 14 The host crystal is made of Na, Al, F, Eu, or other elements, and is called Na5Al3F 14The crystals are assumed to have the same crystal structure as the crystals. However, in Examples 1 to 4, it is believed that the inclusion of Eu makes some of the Na sites vacant. On the other hand, in Examples 5 to 7, it is believed that in addition to Na, Al, F, and Eu, O and / or Mg are present to constitute the host crystal. For example, the X-ray diffraction patterns of Examples 3 and 7 appear almost identical, but while the elements contained in Example 3 are limited to Na, Al, F, and Eu, Example 7 also contains O and / or Mg. Furthermore, in Example 8, it is believed that the inclusion of Eu causes F to partially penetrate interstitially, and the interstitial F is treated as the same crystal structure. When F becomes greater than 14, charge neutrality is maintained. In this way, Na5Al3F 14 Crystal and Na5Al3F 14 The compositions of the products in Examples 1 to 8 were confirmed to be consistent with the designed compositions shown in Table 1. Specifically, in Example 1, Na 4.9 EU 0.05 Al3F 14 , Example 2:Na 4.975 EU 0.0125 Al3F 14 , Example 3:Na 4.95 EU 0.025 Al3F 14 , Example 4:Na 4.8 EU 0.1 Al3F 14 , Example 8:Na 4.975 EU 0.025 Al3F 14.025 It was.

[0048] FIG. 4 shows the excitation and emission spectra of the product of Example 1.

[0049] 4, it was found that the product of Example 1 was efficiently excited by light having a wavelength range of 250 nm or more and less than 380 nm, emitted near-ultraviolet light having a peak at 393 nm, and functioned as a phosphor. It was also confirmed that the phosphor of Example 1 emitted fluorescence with a spectral shape having a half-width of 20 nm or more and 40 nm or less.

[0050] Furthermore, the emission peak wavelength, emission intensity, and half-width of the peak wavelength were determined from the excitation and emission spectra. The results are shown in Table 3. The excitation wavelength used for the measurements was the wavelength with the highest emission intensity in the excitation spectrum. In Table 3, the emission intensities of the phosphors of Examples 2 to 8 are relative intensities to the emission intensity of the phosphor of Example 1.

[0051] [Table 3]

[0052] It was found that the phosphors of Examples 1 to 4 in Table 3, regardless of the amount of Eu added, were all excited by light having a peak in the wavelength range of 250 nm or more and less than 380 nm, and emitted near-ultraviolet light having a peak in the wavelength range of 380 nm or more and 410 nm or less.

[0053] Furthermore, according to Table 3, it was found that the emission intensity increases as the amount of Eu added increases, and that the emission intensity can be increased preferably when the amount of Eu added x is 0.0125 or more and 0.1 or less (0.25 atomic % or more and 2 atomic % or less relative to Na), and more preferably when the amount of Eu added x is 0.025 or more and 0.05 or less (0.5 atomic % or more and 1 atomic % or less relative to Na).

[0054] Furthermore, according to Table 3, the phosphors of Examples 6 to 8 are also Na5Al3F in which oxygen and magnesium are solid-solved, and which emit near-ultraviolet light having a peak in the wavelength range of 380 nm or more and less than 410 nm when excited by light having a peak in the wavelength range of 250 nm or more and less than 380 nm. 14 It was found that crystals having the same crystal structure as the crystals are also effective as host crystals.

[0055] [Light-emitting device: Example 9] FIG. 5 is a schematic diagram showing a lighting fixture (bullet-shaped LED lighting fixture) according to Example 9.

[0056] A bullet-shaped white light-emitting diode lamp (1) as shown in Figure 5 was fabricated. It has two lead wires (2, 3), one of which (2) has a recess on which an ultraviolet light-emitting diode element (4) with an emission peak at 300 nm is mounted. The lower electrode of the ultraviolet light-emitting diode element (4) is electrically connected to the bottom of the recess with conductive paste, and the upper electrode is electrically connected to the other lead wire (3) with a thin gold wire (5). Phosphor (7) is dispersed in resin and mounted near the light-emitting diode element (4). This first resin (6) with dispersed phosphor is transparent and covers the entire light-emitting diode element (4). The tip of the lead wire including the recess, the light-emitting diode element, and the first resin with dispersed phosphor are sealed with a transparent second resin (8). The transparent second resin (8) is approximately cylindrical overall, with its tip having a lens-shaped curved surface, which is commonly referred to as a bullet-shaped lamp.

[0057] In this example, the phosphor powder prepared in Example 1 was mixed with epoxy resin at a concentration of 35% by weight, and an appropriate amount of this was dropped using a dispenser to form a first resin (6) with the phosphor mixed therein (7). The color of the resulting light-emitting device was a color containing a purple luminescent component.

[0058] [Light-emitting device: Example 10] FIG. 6 is a schematic diagram showing a lighting fixture (board-mounted LED lighting fixture) according to Example 10.

[0059] We fabricated a chip-type light-emitting diode lamp (11) for substrate mounting, as shown in Figure 6. Two lead wires (12, 13) are fixed to a white alumina ceramic substrate (19) with high visible light reflectivity. One end of each wire is located approximately in the center of the substrate, and the other ends extend to the outside, forming electrodes that are soldered when mounted on an electrical substrate. An ultraviolet light-emitting diode element (14) with an emission peak wavelength of 320 nm is mounted and fixed to one end of one of the lead wires (12) so that it is in the center of the substrate. The lower electrode of the ultraviolet light-emitting diode element (14) is electrically connected to the lower lead wire with conductive paste, and the upper electrode is electrically connected to the other lead wire (13) with a thin gold wire (15).

[0060] A mixture of first resin (16) and phosphor powder (17) consisting of the phosphor prepared in Example 1, JEM:Ce blue phosphor, β-sialon:Eu, and CaAlSiN3:Eu mixed in a mass ratio of 4:4:1:1 is mounted near the light-emitting diode element. The first resin with the dispersed phosphor is transparent and completely covers the light-emitting diode element (14). A wall member (20) with a central hole is fixed to the ceramic substrate. The wall member (20) has a central hole for receiving the light-emitting diode element (14) and the resin (16) with dispersed phosphor (17), and the portion facing the center is sloped. This slope is a reflective surface for extracting light forward, and the curved shape of the slope is determined taking into account the direction of light reflection. At least the surface constituting the reflective surface is white or metallic, with a high visible light reflectance. In this example, the wall member (20) was made of white silicone resin. The hole in the center of the wall member forms a recess in the final shape of the chip-type light-emitting diode lamp, and this recess is filled with a transparent second resin (18) so as to seal all of the light-emitting diode element (14) and the first resin (16) in which the phosphor (17) is dispersed. In this example, the same epoxy resin was used for the first resin (16) and the second resin (18). A white LED device containing light components in a wide range from 380 nm to 700 nm was obtained. [Industrial Applicability]

[0061] In the embodiments of the present invention, the phosphor may have emission characteristics (emission color, excitation characteristics, emission spectrum) different from those of conventional phosphors. Even when combined with an LED excitation source, the phosphor may have high emission intensity and be chemically and thermally stable. Furthermore, since the phosphor's brightness decreases little when exposed to the excitation source, it is a phosphor that can be suitably used in colored or white LEDs, etc. It is expected that this phosphor will be widely used in the material design of various display devices in the future and will contribute to industrial development. [Explanation of symbols]

[0062] 1. Bullet-shaped light-emitting diode lamp 2, 3 lead wires 4. Light-emitting diode element 5 Gold thin wire 6, 8 Resin 7. Phosphors 11. Chip-type white light-emitting diode lamp for board mounting 12, 13 Lead wires 14 Light-emitting diode element 15 Bonding Wire 16, 18 Resin 17 Phosphor 19 Alumina ceramic substrate 20 Side member

Claims

1. Contains an inorganic compound containing at least sodium (Na), aluminum (Al), fluorine (F), and europium (Eu), The inorganic compound is Na containing at least Eu. ５ Al ３ F １４ Contains crystals, The inorganic compound is a phosphor having a composition of Na 5-2x Eu x Al 3 F 14 (where 0.025≦x≦0.05).

2. 2. The phosphor according to claim 1, which emits fluorescence having a peak in the wavelength range of 380 nm to 410 nm when irradiated with light in the wavelength range of 250 nm to less than 380 nm.

3. 2. The phosphor according to claim 1, which emits fluorescence having a spectral shape with a half-width of 20 nm to 40 nm when irradiated with light having a wavelength in the range of 250 nm to less than 380 nm.

4. 4. The method for producing a phosphor according to claim 1, comprising mixing raw materials containing at least sodium fluoride, europium fluoride, and aluminum fluoride, and reacting the mixture at a temperature in the range of 500°C to 1200°C.

5. A light-emitting device comprising at least a light-emitting source and a phosphor, the light emitting source emits light in a wavelength range of 250 nm or more and less than 380 nm, A light-emitting device, wherein the phosphor comprises the phosphor according to any one of claims 1 to 3.

6. 6. The light-emitting device according to claim 5, wherein the phosphor further comprises a blue phosphor having a peak emission wavelength in the range of 440 nm to 500 nm, a green phosphor having a peak emission wavelength in the range of 500 nm to 580 nm, and a red phosphor having a peak emission wavelength in the range of 600 nm to 700 nm.

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