Nitride phosphor, light-emitting device, and method for producing nitride phosphor

Abstract

Provided are a nitride phosphor, a light-emitting device, and a method for producing the nitride phosphor.　This nitride phosphor has a composition represented by formula (1).　(1): M1 sM2 tM3 x(Al1-uM4 u)vNwR5 y (In formula (1), M1 is at least one element selected from the group consisting of Sr, Ca, Ba, and K; M2 is at least one element selected from the group consisting of Li, Na, and Mg; M3 is at least one element selected from the group consisting of Eu, Mn, Ce, and Tb; M4 is at least one element selected from the group consisting of Ga, In, and B; R5 is at least one element selected from the group consisting of F, Cl, Br, and I; and s, t, u, v, w, x, and y respectively satisfy 0.7 ≤ s ≤ 1.3, 0.7 ≤ t ≤ 1.45, 0 < u ≤ 0.38, 2.4 ≤ v ≤ 3.7, 3.0 ≤ w ≤ 5.0, 0 < x ≤ 0.2, and 0.2 < y ≤ 0.8.　

Description

Nitride phosphor, light-emitting device, and method for manufacturing nitride phosphor

[0001] The present disclosure relates to a nitride phosphor, a light emitting device, and a method for manufacturing the nitride phosphor.

[0002] Light-emitting devices that combine light-emitting diodes (LEDs) and phosphors are used in lighting devices, backlights for liquid crystal displays, small strobe lights, etc. Light-emitting devices use nitride phosphors that emit red light.

[0003] Patent Document 1 describes a SrLiAl ３ N ４ :Eu)。 Disclosed is a nitride phosphor having a composition represented by the formula:

[0004] International Publication No. 2013 / 175336

[0005] Phosphors are sometimes required to have superior light-emitting properties, for example, to emit light with high internal quantum efficiency. An object of the present disclosure is to provide a nitride phosphor that emits red light with high internal quantum efficiency, a light-emitting device, and a method for manufacturing the nitride phosphor.

[0006] The first aspect is a nitride phosphor having a composition represented by the following formula (1): M １ ｓ M ２ ｔ M ３ ｘ (Al １－ｕ M ４ ｕ ) ｖ N ｗ R ５ ｙ (1) (In the above formula (1), M １ is at least one element selected from the group consisting of Sr, Ca, Ba, and K, and M ２ is at least one element selected from the group consisting of Li, Na, and Mg, and M ３ is at least one element selected from the group consisting of Eu, Mn, Ce, and Tb, and M ４ is at least one element selected from the group consisting of Ga, In, and B, and R ５is at least one element selected from the group consisting of F, Cl, Br, and I, and s, t, u, v, w, x, and y satisfy the following relationships, respectively: 0.7≦s≦1.3, 0.7≦t≦1.45, 0<u≦0.38, 2.4≦v≦3.7, 3.0≦w≦5.0, 0<x≦0.2, 0.2<y≦0.8.

[0007] A second aspect is a light emitting device comprising the nitride phosphor and a light emitting element having an emission peak wavelength in the range of 300 nm to 500 nm, which irradiates the nitride phosphor with excitation light.

[0008] The third aspect is a method for manufacturing a semiconductor device using at least one element M selected from the group consisting of Sr, Ca, Ba, and K. １ and at least one element M selected from the group consisting of Li, Na, and Mg. ２ and at least one element M selected from the group consisting of Eu, Mn, Ce, and Tb. ３ a third compound containing Al; a fourth compound containing at least one element M selected from the group consisting of Ga, In, and B; ４ and at least one element R selected from the group consisting of F, Cl, Br, and I. ５ and a sixth compound containing the element M, wherein at least one compound among the first compound to the fifth compound is a nitride; １ and an element M contained in the second compound. ２ and an element M contained in the third compound. ３ and Al contained in the fourth compound, and element M contained in the fifth compound. ４ and M are mixed together so as to satisfy the molar ratio in the composition represented by the following formula (1a), and when the total amount of the first compound to the fifth compound is taken as 100 mass %, the sixth compound is added as a flux so as to be more than 3 mass % but not more than 9 mass % to obtain a raw material mixture, and heat-treating the raw material mixture at a temperature less than 1000°C to obtain a heat-treated product. １ ｓ M ２ ｔ M ３ｘ (Al １－ｕ M ４ ｕ ) ｖ N ｗ (1a) (In the formula (1a), s, t, u, v, w, and x satisfy the following conditions: 0.7≦s≦1.3, 0.7≦t≦1.45, 0<u≦0.38, 2.4≦v≦3.7, 3.0≦w≦5.0, and 0<x≦0.2, respectively.)

[0009] According to the present disclosure, it is possible to provide a nitride phosphor that emits red light with high internal quantum efficiency, a light emitting device, and a method for manufacturing the nitride phosphor.

[0010] Fig. 1 is a schematic cross-sectional view showing a first configuration example of a light emitting device; Fig. 2 is a schematic plan view showing a second configuration example of a light emitting device; Fig. 3 is a schematic cross-sectional view showing a second configuration example of a light emitting device; Fig. 4 is a diagram showing the emission spectra of nitride phosphors according to Examples 1 to 4, and the emission spectrum of a nitride phosphor of Comparative Example 1; Fig. 5 is a diagram showing the emission spectra of the nitride phosphors according to Examples 1 to 4, the nitride phosphor of Comparative Example 1, and SrLiAl ３ N ４ 1 is a powder X-ray diffraction pattern showing the crystal structure of the nitride phosphor according to Examples 4 to 6, and a graph showing the emission spectra of the nitride phosphor according to Comparative Examples 2 to 4.

[0011] The nitride phosphor, light-emitting device, and method for manufacturing the nitride phosphor according to the present disclosure are described below. However, the embodiments shown below are merely examples for embodying the technical concept of the present invention, and the present invention is not limited to the nitride phosphor, light-emitting device, and method for manufacturing the nitride phosphor described below. Regarding visible light, the relationship between color names and chromaticity coordinates, the relationship between light wavelength ranges and color names of monochromatic light, etc., conforms to JIS Z8110. The full width at half maximum refers to the wavelength width at which the emission intensity is 50% of the emission intensity at the emission peak wavelength showing the maximum emission intensity in the emission spectrum.

[0012] The nitride phosphor has a composition represented by the following formula (1): １ ｓ M ２ ｔ M ３ ｘ (Al １－ｕ M ４ｕ ) ｖ N ｗ R ５ ｙ (1) (In the above formula (1), M １ is at least one element selected from the group consisting of Sr, Ca, Ba, and K, and M ２ is at least one element selected from the group consisting of Li, Na, and Mg, and M ３ is at least one element selected from the group consisting of Eu, Mn, Ce, and Tb, and M ４ is at least one element selected from the group consisting of Ga, In, and B, and R ５ is at least one element selected from the group consisting of F, Cl, Br, and I, and s, t, u, v, w, x, and y satisfy the following relationships, respectively: 0.7≦s≦1.3, 0.7≦t≦1.45, 0<u≦0.38, 2.4≦v≦3.7, 3.0≦w≦5.0, 0<x≦0.2, 0.2<y≦0.8.

[0013] The nitride phosphor has a composition represented by the formula (1) in which the element M １ , element M ２ , Al, element M ４ , and N are elements that form the framework of the host crystal of the phosphor, and element M ３ is an activator element. In the crystal structure of the host crystal of the nitride phosphor, element M １ is the element M １ A hexahedron structure is formed with nitrogen at the eight corners, with element M ２ and Al is the element M ２ In the composition of the nitride phosphor represented by the formula (1), the element R ５ is a flux added to enhance the reactivity of the raw material or an element derived from the raw material of the nitride phosphor.

[0014] The nitride phosphor has a composition represented by the formula (1), in which a part of Al in the crystal structure is replaced by the element M. ４ The nitride phosphor emits light having a peak emission wavelength in a desired range when irradiated with excitation light. ４The nitride phosphor has a composition represented by the formula (1), in which the element R is present in an amount of 0.2 or more and 0.8 or less (0.2<y≦0.8) per mole of the composition. ５ The inclusion of α-methyl-2-(2-methyl-2-propanol) increases the reactivity of the raw materials and suppresses the generation of defects in the crystal structure, resulting in a highly crystalline phosphor with a long fluorescence lifetime. Fluorescence lifetime refers to the time it takes for electrons in the ground energy level to absorb light, become excited, and then emit photons to return to the ground state. Fluorescence lifetime refers to the time it takes for the maximum emission intensity of light emitted from a phosphor irradiated with excitation light (specifically, the emission intensity when the excitation light irradiation is blocked) to decay to an intensity of 1 / e (36.8%). When irradiated with light, electrons in the ground energy level absorb light and become excited, raising the energy level. Electrons in the high energy level move to a lower energy level while releasing thermal energy through lattice relaxation, and then emit light by radiative transition, releasing energy as light, and then return to the lowest energy level, the ground state. Phosphors with few defects in their crystal structure and high crystallinity have a high probability of radiative transition, making it easier for the energy of excited electrons to be released as light, which means it takes longer for the emission intensity to decay and a longer fluorescence lifetime. If there are many defects in the crystal structure of a phosphor, the probability of excited electrons moving to the energy level of the defects and then returning to the ground state without emitting light as a non-radiative transition increases, resulting in a faster decay of emission intensity and a shorter fluorescence lifetime. Phosphors with similar host crystal structures and the same activator element have a longer fluorescence lifetime, with fewer defects in the crystal structure and higher crystallinity, and emit light with a higher internal quantum efficiency.

[0015] The composition of the nitride phosphor may contain trace amounts of halogen elements (e.g., fluorine) or oxygen contained in the atmosphere during the manufacturing process, to the extent that they cannot be expressed as a molar ratio in the composition. A trace amount that cannot be expressed as a molar ratio in the phosphor composition refers to a halogen element (e.g., fluorine) content of less than 100 ppm by mass, for example, several ppm by mass to several tens of ppm by mass, when the nitride phosphor is taken as 100% by mass. Furthermore, the composition of the nitride phosphor may contain halogen elements contained in the atmosphere during the manufacturing process or in the halide raw material, in an amount of about 0.2 mol or less per mol of the phosphor composition.

[0016] The nitride phosphor has a composition represented by the formula (1) in which the element R ５ is at least one element selected from the group consisting of F, Cl, Br and I. The nitride phosphor has a composition represented by the formula (1) in which the element R ５ Preferably, the element R contains F. ５ When R is fluorine (F), the ionic radius of F is close to that of nitrogen (N) that constitutes the crystal structure of the nitride phosphor, and therefore defects in the crystal structure are easily suppressed. ５ may contain F and at least one element selected from the group consisting of Cl, Br, and I. The nitride phosphor may contain, in the composition represented by the formula (1), an element R ５ However, F is also acceptable.

[0017] The nitride phosphor having the composition represented by the formula (1) contains an element R ５ The variable y representing the molar ratio of element R in 1 mol of the composition represented by the formula (1) of the nitride phosphor is more than 0.2 and not more than 0.8 (0.2<y≦0.8). ５ The molar ratio of element R in 1 mole of the composition is such that the amount of halogen element contained in the atmosphere during the manufacturing process is greater than the amount of halogen element contained in the phosphor. ５ The molar ratio of Al is higher than that of the halogen element contained in the atmosphere during the manufacturing process. ４Since a part of Al is substituted with element M ４ It is presumed that the temperature at which the raw materials are heat treated is lower than when a nitride phosphor having a composition in which the halogen element is not substituted with is produced, and the halogen element does not scatter and is easily contained in the nitride phosphor. ４ Since the element is substituted with nitrogen (N), distortion of the crystal structure is likely to occur, and the element R, which is a halogen element with a smaller ionic radius than nitrogen (N), which is an element constituting the crystal structure, is present in the portion where distortion is likely to occur. ５ For example, fluorine (F) can easily enter the element R ５ It is presumed that the nitride phosphor having the composition represented by the formula (1) is easily contained in the element M. ２ or element M ４ is easily dispersed from the composition, and element M ２ and element M ４ The element R, which is a halogen element with a smaller valence than nitrogen (N), is easily scattered and cation defects are easily generated, which makes it easy for the positive charge to decrease. ５ For example, fluorine (F) is more likely to compensate for the cation defects that reduce the positive charge in the nitride phosphor, so the element R ５ It is presumed that the nitride phosphor having the composition represented by the formula (1) is likely to contain the element R in 1 mole of the composition. ５ Since the variable y representing the molar ratio of element R is greater than 0.2 and not more than 0.8 (0.2<y≦0.8), defects in the crystal structure are suppressed, resulting in high crystallinity and a long fluorescence lifetime. ５ The variable y representing the molar ratio may be in the range of 0.25 or more and 0.8 or less (0.25≦y≦0.8), may be in the range of 0.3 or more and 0.8 or less (0.3≦y≦0.8), or may be in the range of 0.35 or more and 0.79 or less (0.35≦y≦0.79).

[0018] The nitride phosphor has a composition represented by the formula (1) in which the element M １ is at least one element selected from the group consisting of Sr, Ca, Ba and K. １is the element M in the crystal structure of the host crystal that constitutes the nitride phosphor. １ It forms a hexahedron with nitrogen atoms at the eight corners, with element M at the center. １ In order to stabilize the crystal structure of the nitride phosphor, it is preferable that the element M is an element having a similar ionic radius in the composition represented by the formula (1). １ Preferably, the nitride phosphor contains Sr in the composition represented by the formula (1). １ may contain Sr and at least one element selected from the group consisting of Ca, Ba and K. In the composition represented by the formula (1), the nitride phosphor may contain the element M １ may be Sr.

[0019] The nitride phosphor having the composition represented by the formula (1) contains the element M １ The variable s representing the molar ratio of element M is in the range of 0.7 to 1.3 (0.7≦s≦1.3). １ If the variable s, which represents the molar ratio of element M, is within the range of 0.7 to 1.3, the crystal structure of the host crystal is stable and the crystallinity is likely to be high. In the present specification, "high crystallinity" means that the crystal structure of the host crystal is regularly stable. The nitride phosphor has a composition represented by the formula (1) in which the element M １ The variable s representing the molar ratio may be in the range of 0.8 to 1.2 (0.8≦s≦1.2), in the range of 0.9 to 1.1 (0.9≦s≦1.1), or may be 1 (s=1).

[0020] The nitride phosphor has a composition represented by the formula (1) in which the element M ２ is at least one element selected from the group consisting of Li, Na, and Mg. ２ is the element M in the crystal structure of the host crystal that constitutes the nitride phosphor. ２ It forms a tetrahedron with nitrogen atoms at the four corners and with element M at the center. ２In order to stabilize the crystal structure of the nitride phosphor, it is preferable that the element M is an element having no large difference in ionic radius in the composition represented by the formula (1). ２ It is preferable that the nitride phosphor contains Li in the composition represented by the formula (1). ２ The nitride phosphor may contain Li and at least one element selected from the group consisting of Na and Mg. ２ may be Li.

[0021] The nitride phosphor having the composition represented by the formula (1) contains the element M ２ The variable t representing the molar ratio of element M is in the range of 0.7 to 1.45 (0.7≦t≦1.45). ２ When the variable t, which represents the molar ratio of element M, is in the range of 0.7 to 1.45, the crystal structure of the host crystal is stable and the crystallinity is likely to be high. ２ The variable t representing the molar ratio may be in the range of 0.8 to 1.44 (0.8≦t≦1.44), in the range of 0.9 to 1.43 (0.9≦t≦1.43), or may be 1 (t=1).

[0022] The nitride phosphor has a composition represented by the formula (1) in which the element M ３ is at least one element selected from the group consisting of Eu, Mn, Ce and Tb. ３ is an activator element of the nitride phosphor. In order to emit light having an emission peak wavelength in a desired wavelength range when irradiated with excitation light, the element M ３ Preferably, the nitride phosphor contains Eu in the composition represented by the formula (1). ３ The nitride phosphor may contain Eu and at least one element selected from the group consisting of Mn, Ce, and Tb. ３ may be Eu.

[0023] The nitride phosphor having the composition represented by the formula (1) contains the element M ３ The variable x representing the molar ratio of the element M is greater than 0 and is equal to or less than 0.2 (0<x≦0.2). ３ When the variable x representing the molar ratio of element M is in the range of more than 0 to 10.2 or less, the nitride phosphor emits light having an emission peak wavelength in a desired range when irradiated with excitation light. ３ The variable x representing the molar ratio is preferably in the range of 0.001 or more and 0.1 or less (0.001≦x≦0.1), may be in the range of 0.002 or more and 0.08 or less (0.002≦x≦0.08), may be in the range of 0.003 or more and 0.05 or less (0.003≦x≦0.05), may be in the range of 0.003 or more and 0.02 or less (0.003≦x≦0.02), or may be in the range of 0.003 or more and 0.015 or less (0.003≦x≦0.015).

[0024] The nitride phosphor has a composition represented by the formula (1) in which the element M ４ is at least one element selected from the group consisting of Ga, In and B. ４ is a crystalline structure of the host crystal constituting the nitride phosphor, and replaces a part of Al, and is replaced by Al or element M. ４ It forms a tetrahedron with nitrogen atoms at the four corners and with element M at the center. ４ Since M is arranged at the same site as Al in the crystal structure of the host crystal that constitutes the nitride phosphor, it is preferable that M is an element having an ionic radius close to the ionic radius of Al. ４ It is preferable that the nitride phosphor contains Ga in the composition represented by the formula (1). ４ may contain Ga and at least one element selected from the group consisting of In and B. The nitride phosphor may contain Ga and at least one element selected from the group consisting of In and B. ４ may be Ga.

[0025] The nitride phosphor having the composition represented by the formula (1) contains the element M４ In the product of the variables u and v representing the molar ratio of Al and M, the variable u is greater than 0 and not greater than 0.38 (0<u≦0.38). ４ When the total molar ratio of Al is 1, the element M ４ When the variable u representing the molar ratio of Al and element M is in the range of more than 0 and not more than 0.38, the nitride phosphor has a host crystal that emits light having a desired emission peak wavelength when irradiated with excitation light. ４ When the total molar ratio of Al is 1, the element M ４ When the variable u representing the molar ratio of Al and M exceeds 0.38, distortion is likely to occur in the crystal structure, and the internal quantum efficiency of light emitted by irradiation with excitation light may decrease. ４ When the total molar ratio of Al is 1, the element M ４ When the variable u representing the molar ratio of element M becomes 0.5, ４ The nitride phosphor has a composition represented by the formula (1) in which the element M reaches a limit of substitution, and the internal quantum efficiency of light emitted by irradiation with excitation light decreases. ４ The variable u representing the molar ratio may be 0.36 or less (u≦0.36), 0.35 or less (u≦0.35), 0.34 or less (u≦0.34), 0.005 or more (0.005≦u), 0.01 or more (0.01≦u), or within the range of 0.01 or more and 0.33 or less (0.01≦u≦0.33).

[0026] The nitride phosphor has a composition represented by the formula (1) in which Al and element M ４ In the nitride phosphor having the composition represented by the formula (1), the molar ratio of Al is expressed by the product of the value obtained by subtracting the variable u from 1 and the variable v, and the element M ４The molar ratio is expressed as the product of the variable u and the variable v. In order to stabilize the crystal structure of the nitride phosphor, in the composition expressed by the formula (1), the variable v may be in the range of 2.5 to 3.6 (2.5≦v≦3.6), in the range of 2.6 to 3.5 (2.6≦v≦3.5), in the range of 2.8 to 3.2 (2.5≦v≦3.2), or 3 (v=3).

[0027] In the nitride phosphor, in the composition represented by the formula (1), the variable w representing the molar ratio of N is in the range of 3.0 to 5.0 (3.0≦w≦5.0). To stabilize the crystal structure, in the nitride phosphor, in the composition represented by the formula (1), the variable w may be in the range of 3.1 to 4.9 (3.1≦w≦4.9), 3.2 to 4.8 (3.2≦w≦4.8), or 3.5 to 4.5 (3.5≦w≦4.5).

[0028] The nitride phosphor has a stable crystal structure and emits light having a peak emission wavelength in a desired range when irradiated with excitation light. １ contains Sr, and M ２ contains Li, and M ３ contains Eu, and M ４ It is preferable that contains Ga.

[0029] The nitride phosphor has a stable crystal structure and emits light having a peak emission wavelength in a desired range when irradiated with excitation light. １ is Sr, and M ３ is Eu, and M ４ may be Ga.

[0030] The nitride phosphor is a compound represented by the formula (1): ３is preferably Eu, and the fluorescence lifetime of the nitride phosphor is preferably 750 ns (nanoseconds) or more. The fluorescence lifetime can be measured by irradiating the nitride phosphor with excitation light, measuring the change in fluorescence intensity of the nitride phosphor over time from the point at which the irradiation of the excitation light is stopped, and taking the fluorescence intensity at the time of stopping the excitation light as 100%, as the time required for the fluorescence intensity to decay to 1 / e (36.8%) of the time at which the excitation light was stopped. e is the base of the natural logarithm and is Napier's constant. For example, the excitation light used to measure the fluorescence lifetime is excitation light with an emission peak wavelength of 442 nm. The fluorescence lifetime varies depending on the crystal structure of the host crystal of the phosphor, the activator element, etc. The fewer defects there are in the crystal structure of the nitride phosphor and the higher the crystallinity, the longer the fluorescence lifetime. The nitride phosphor has a composition represented by the above formula (1), in which the element M, which is an activator element, ３ is Eu, and the molar ratio of element R in 1 mole of the composition represented by the formula (1) is more than 0.2 and 0.8 or less (0.2<y≦0.8). ５ Since the nitride phosphor contains the element R in 1 mole of the composition represented by the formula (1), the reactivity of the raw material is increased and the generation of defects in the crystal structure is suppressed, resulting in a phosphor with high crystallinity and a long fluorescence lifetime. ５ When the molar ratio of M in the formula (1) is 0.2 or less, defects tend to be included in the crystal structure of the phosphor, resulting in a fluorescence lifetime of less than 750 ns. The nitride phosphor having the composition represented by the formula (1) has a fluorescence lifetime of 900 ns or less even when the crystal structure does not contain defects. ３ is Eu, and the fluorescence lifetime of the nitride phosphor is more preferably 755 ns or more, further preferably 760 ns or more, and may be 880 ns or less.

[0031] When irradiated with excitation light having a peak emission wavelength in the range of 300 nm to 500 nm, the nitride phosphor preferably emits fluorescence having a peak emission wavelength in the range of 620 nm to 655 nm, and more preferably emits fluorescence having a peak emission wavelength in the range of 630 nm to 650 nm. The nitride phosphor preferably has a full width at half maximum in its emission spectrum in the range of 45 nm to 65 nm, and more preferably in the range of 50 nm to 60 nm. Nitride phosphors having a full width at half maximum in their emission spectrum in the range of 45 nm to 65 nm have a relatively narrow full width at half maximum in their emission spectrum and a wide color reproduction range, making them suitable as phosphors for use in light-emitting devices used in, for example, liquid crystal display devices.

[0032] The average particle size of the nitride phosphor is preferably 4.0 μm or more, more preferably 4.5 μm or more, even more preferably 5.0 μm or more, and preferably 30 μm or less, more preferably 25 μm or less. When the average particle size of the nitride phosphor is a predetermined value or more, the internal quantum efficiency is high. Nitride phosphors having an average particle size of a predetermined value or less are easy to handle, and can improve the workability in the manufacturing process of light-emitting devices. In this specification, the average particle size of the nitride phosphor is the particle size (D50: median diameter) at which the volume cumulative frequency from the smallest diameter side reaches 50% as measured using a laser diffraction particle size distribution measuring device (e.g., MASTER SIZER 2000 manufactured by MALVERN).

[0033] The light emitting device includes the nitride phosphor and a light emitting element having an emission peak wavelength in the range of 300 nm to 500 nm, which irradiates the nitride phosphor with excitation light. The nitride phosphor is preferably contained in a wavelength conversion member, and the wavelength conversion member may include a light-transmitting material.

[0034] A semiconductor element can be used as the light emitting element that irradiates the nitride phosphor with excitation light. For example, nitride semiconductors can be selected as materials for light emitting elements that emit green and blue light. In is used as a material for the semiconductor structure that constitutes the light emitting element. Ｘ Al Ｙ Ga １－Ｘ－ＹN (0≦X≦1, 0≦Y≦1, X+Y≦1), etc., can be used. As a material for the light-emitting element that emits red light, for example, a gallium-aluminum-arsenic-based semiconductor or an aluminum-indium-gallium-phosphorus-based semiconductor can be selected. As the light-emitting element, it is preferable to use, for example, an LED chip or an LD chip.

[0035] The light-emitting element has an emission peak wavelength in the range of 300 nm to 500 nm, and may have an emission peak wavelength in the range of 350 nm to 500 nm, 360 nm to 490 nm, or 370 nm to 480 nm. A light-emitting device can be constructed using the light-emitting element as an excitation light source, emitting mixed light of a desired wavelength range from the light from the light-emitting element and the fluorescence from a phosphor containing a nitride phosphor. The full width at half maximum of the emission peak in the emission spectrum of the light-emitting element can be, for example, 30 nm or less. It is preferable to use a light-emitting element using, for example, a nitride-based semiconductor as the light-emitting element. By using a light-emitting element using a nitride-based semiconductor as the excitation light source, a stable light-emitting device can be obtained that is highly efficient, has high output linearity relative to input, and is resistant to mechanical shock.

[0036] An example of a light emitting device will be described with reference to the drawings. Fig. 1 is a schematic cross-sectional view showing a first configuration example of a light emitting device.

[0037] As shown in FIG. 1 , the light-emitting device 100 includes a molded body 40 having a recess, a light-emitting element 10 serving as an excitation light source, and a wavelength conversion member 50 covering the light-emitting element 10. The molded body 40 is formed by integrally molding a first lead 20, a second lead 30, and a resin portion 42 containing a thermoplastic resin or a thermosetting resin. In the molded body 40, at least the first lead 20 and the second lead 30 form the bottom surface of the recess, and at least the resin portion 42 forms the side surface of the recess. The light-emitting element 10 is placed on the bottom surface of the recess of the molded body 40. The light-emitting element 10 has a pair of positive and negative electrodes, which are electrically connected to the first lead 20 and the second lead 30 via wires 60, respectively. The light-emitting element 10 is covered with a wavelength conversion member 50. The wavelength conversion member 50 preferably includes a phosphor 70 that converts the wavelength of light emitted from the light-emitting element 10, and a translucent material. The phosphor 70 essentially includes a first phosphor 71 containing a nitride phosphor. The nitride phosphor included in the first phosphor 71 contains a nitride phosphor having a composition represented by formula (1). The phosphor 70 may include a second phosphor 72 having an emission peak wavelength in a wavelength range different from the emission peak wavelength of the first phosphor 71 and having a composition different from that of the first phosphor 71. The wavelength conversion member 50 also functions as a member for protecting the light emitting element 10, the wire 60, the phosphor 70, etc. from the external environment. The light emitting device 100 emits light upon receiving a supply of power from an external source via the first lead 20 and the second lead 30.

[0038] 2 and 3 show a second configuration example of a light-emitting device. FIG. 2 is a schematic plan view of the light-emitting device 200. FIG. 3 is a schematic cross-sectional view of the light-emitting device 200 shown in FIG. 2 taken along line II-II'. The light-emitting device 200 includes a light-emitting element 10 having an emission peak wavelength in the range of 365 nm to 650 nm, a wavelength converter 52 including a first phosphor 71 that emits light upon excitation by light from the light-emitting element 10, and a wavelength conversion member 51 including a light-transmitting body 53 disposed on the light-emitting surface side of the wavelength converter 52. The light-emitting element 10 is flip-chip mounted on the substrate 1 via bumps that are conductive members 61. The wavelength converter 52 of the wavelength conversion member 51 is disposed on the light-emitting surface of the light-emitting element 10 via an adhesive layer 80. The light-emitting element 10 and the wavelength conversion member 51 have their side surfaces covered by a light-reflective covering member 90. The wavelength converter 52 is excited by light from the light-emitting element 10 and essentially includes a first phosphor 71 containing a nitride phosphor having a composition represented by formula (1). The wavelength converter 52 may include a phosphor having an emission peak wavelength in a wavelength range different from the emission peak wavelength of the first phosphor 71 and having a different composition from that of the first phosphor 71. The wavelength converter 52 essentially includes the first phosphor 71 and may also include a second phosphor having a different composition from that of the first phosphor. The light-emitting element 10 can receive power from outside the light-emitting device 200 via wiring and a conductive member 61 formed on the substrate 1, causing the light-emitting device 200 to emit light. The light-emitting device 200 may include a semiconductor element 11, such as a protective element, to protect the light-emitting element 10 from damage due to application of excessive voltage. The semiconductor element 11 may be mounted on the substrate 1 via the conductive member 61. The covering member 90 is arranged to cover the semiconductor element 11, for example. Each component used in the light-emitting device will be described below. For details, see, for example, the disclosure of Japanese Patent Application Laid-Open No. 2014-112635.

[0039] The translucent material constituting the wavelength converter together with the phosphor may be at least one selected from the group consisting of resin, glass, and inorganic materials. The resin may be at least one selected from the group consisting of silicone resin, epoxy resin, phenolic resin, polycarbonate resin, acrylic resin, and modified resins thereof. Silicone resin and modified silicone resin are preferred because of their excellent heat resistance and light resistance. In addition to the phosphor and the translucent material, the wavelength converter may also contain a filler, a colorant, and a light diffusing material as needed. Examples of fillers include silicon oxide, barium titanate, titanium oxide, and aluminum oxide.

[0040] The light-transmitting body can be a plate-shaped body made of a light-transmitting material such as glass or resin. Examples of glass include borosilicate glass and quartz glass. Examples of resin include silicone resin and epoxy resin. When the wavelength conversion member includes a substrate, the substrate is preferably made of an insulating material that is difficult to transmit light from the light-emitting element and external light. Examples of materials for the substrate include ceramics such as aluminum oxide and aluminum nitride, and resins such as phenolic resin, epoxy resin, polyimide resin, bismaleimide triazine resin (BT resin), and polyphthalamide (PPA) resin. When an adhesive layer is interposed between the light-emitting element and the wavelength conversion member, the adhesive constituting the adhesive layer is preferably made of a material that can optically connect the light-emitting element and the wavelength conversion member. The material constituting the adhesive layer is preferably at least one resin selected from the group consisting of epoxy resin, silicone resin, phenolic resin, and polyimide resin. The light-transmitting body does not have to be disposed on the wavelength conversion member.

[0041] Examples of semiconductor elements that may be optionally provided in a light-emitting device include transistors for controlling light-emitting elements and protective elements for preventing damage or performance degradation of light-emitting elements due to excessive voltage application. Examples of protective elements include Zener diodes. When a light-emitting device includes a covering member, an insulating material is preferably used as the covering member material. More specifically, examples include phenolic resin, epoxy resin, bismaleimide triazine resin (BT resin), polyphthalamide (PPA) resin, and silicone resin. Colorants, phosphors, and fillers may be added to the covering member as needed. The light-emitting device may also use bumps as conductive members. Examples of materials for the bumps include Au or its alloys, and other conductive materials include eutectic solder (Au-Sn), Pb-Sn, and lead-free solder.

[0042] An example of a method for manufacturing the light emitting device of the first configuration example will be described. For details, the disclosure of JP 2010-062272 A can be referenced, for example. The method for manufacturing the light emitting device preferably includes a molded body preparation step, a light emitting element arrangement step, a wavelength conversion member forming composition arrangement step, and a resin package formation step. When an aggregate molded body having a plurality of recesses is used as the molded body, the resin package formation step may be followed by a singulation step of separating the molded body into individual unit area resin packages.

[0043] In the step of preparing a molded body, a plurality of leads are integrally molded using a thermosetting resin or a thermoplastic resin to prepare a molded body having a recess with side and bottom surfaces. The molded body may be a molded body made of an aggregate base including a plurality of recesses.

[0044] In the light-emitting element placement step, the light-emitting element is placed on the bottom surface of the recess in the molded body, and the positive and negative electrodes of the light-emitting element are connected to the first lead and the second lead by wires.

[0045] In the step of placing the composition for forming a wavelength conversion member, the composition for forming a wavelength conversion member is placed in the recess of the molded body.

[0046] In the resin package molding step, the wavelength conversion member-forming composition placed in the recesses of the molded body is cured to form a resin package, thereby manufacturing a light-emitting device. When a molded body made of an aggregate substrate including a plurality of recesses is used, after the resin package formation step, the aggregate substrate having a plurality of recesses is separated into resin packages of each unit region in a singulation step, and individual light-emitting devices are manufactured. In this manner, the light-emitting device shown in FIG. 1 or 2 can be manufactured.

[0047] An example of a manufacturing method for the light emitting device of the second configuration example will be described. For details, the disclosures of Japanese Patent Application Laid-Open No. 2014-112635 or Japanese Patent Application Laid-Open No. 2017-117912 can be referenced. The manufacturing method for the light emitting device preferably includes a step of arranging a light emitting element, a step of arranging a semiconductor element if necessary, a step of forming a wavelength conversion member including a wavelength converter, a step of bonding the light emitting element and the wavelength conversion member, and a step of forming a covering member.

[0048] For example, in the light-emitting element placement step, the light-emitting element is placed on a substrate. The light-emitting element and the semiconductor element are, for example, flip-chip mounted on the substrate. Next, in the wavelength conversion member formation step including a wavelength converter, the wavelength converter may be obtained by forming a plate-shaped, sheet-shaped, or layer-shaped wavelength converter on one surface of a translucent body using a printing method, an adhesive method, a compression molding method, or an electrodeposition method. For example, the printing method can be used to print a wavelength conversion member containing a phosphor and a binder or solvent resin on one surface of a translucent body to form a wavelength conversion member containing a wavelength converter. Next, in the bonding step between the light-emitting element and the wavelength conversion member, the wavelength conversion member is placed opposite the light-emitting surface of the light-emitting element, and the wavelength conversion member is bonded to the light-emitting element with an adhesive layer. Next, in the coating member formation step, the side surfaces of the light-emitting element and the wavelength conversion member are covered with a coating member composition. This coating member is intended to reflect light emitted from the light-emitting element. If the light-emitting device also includes a semiconductor element, it is preferable that the semiconductor element be embedded in the coating member. In this manner, the light-emitting device shown in Figures 3 and 4 can be manufactured.

[0049] The method for producing a nitride phosphor includes adding at least one element M selected from the group consisting of Sr, Ca, Ba, and K.１ and at least one element M selected from the group consisting of Li, Na, and Mg. ２ and at least one element M selected from the group consisting of Eu, Mn, Ce, and Tb. ３ a third compound containing Al; a fourth compound containing at least one element M selected from the group consisting of Ga, In, and B; ４ and at least one element R selected from the group consisting of F, Cl, Br, and I. ５ and a sixth compound containing an element M contained in the first compound, and at least one compound of the first compound to the fifth compound is a nitride. １ and an element M contained in the second compound. ２ and an element M contained in the third compound. ３ Al contained in the fourth compound, and element M contained in the fifth compound. ４ and are mixed so as to satisfy the molar ratio in the composition represented by the following formula (1a), and when the total amount of the first compound to the fifth compound is taken as 100 mass%, the element R ５ and heat-treating the raw material mixture at a temperature of less than 1000°C to obtain a heat-treated product. １ ｓ M ２ ｔ M ３ ｘ (Al １－ｕ M ４ ｕ ) ｖ N ｗ (1a) (In the formula (1a), s, t, u, v, w, and x satisfy the following conditions: 0.7≦s≦1.3, 0.7≦t≦1.45, 0<u≦0.38, 2.4≦v≦3.7, 3.0≦w≦5.0, and 0<x≦0.2, respectively.)

[0050] element M １ The first compound containing the element M １ Nitrides containing element M １ and halides containing element M １ hydrides containing the element M１ The halide containing the element M is preferably a fluoride. １ Specifically, the first compound containing Sr ２ N, SrN, Sr ３ N ２ , SrH ２、 SrF ２ , Ca ３ N ２ , CaH ２ , CaF ２ , Ba ３ N ２ , BaH ２ , BaF ２ , KF, and KH, and at least one selected from the group consisting of these is preferred. ２ When the first compound is used as a raw material, it may act as a flux. １ In the composition represented by the formula (1a), an imide compound, an amide compound, or the like containing the element M may be used. １ When K is contained in the second compound, for example, when the second compound is a compound containing Li, the K may be derived from a compound in which part of Li is substituted with K. The first compound may be used alone or in combination of two or more. The first compound is preferably a compound containing Sr.

[0051] element M ２ The second compound containing the element M ２ is an alkali metal element, the element M ２ Nitrides containing element M ２ hydrides containing element M ２ Examples of the compound include amide compounds and imide compounds containing the element M. ２ is an alkaline earth metal element, the element M ２ Nitrides containing element M ２ and hydrides containing element M ２ Examples of the halides include those containing the element M. ２ The halide containing the element M is preferably a fluoride. ２ Specifically, the second compound containing Li ３ N, LiN ３, LiH, LiAlH ４ , LiNH ２ , NaH, Mg ３ N ２ , MgH ２ , and MgF ２ In the composition represented by the formula (1a), the element M ２ When Na is contained in the second compound, for example, when the second compound is a compound containing Li, the Na may be derived from a compound in which part of Li is substituted with Na. The second compound may be used alone or in combination of two or more. The second compound is preferably a compound containing Li.

[0052] element M ３ The third compound containing the element M ３ hydrides containing element M ３ oxides containing element M ３ Nitrides containing element M ３ Examples of the halides include those containing the element M. ３ The halide containing the element M is preferably a fluoride. ３ The third compound containing the element M ３ Metal or element M represented by ３ The element M may be an alloy containing the element M, and a part of the element M may be replaced with another metal. ３ The third compound containing EuH ２ , Eu ２ O ３ , EuN, EuF ３ , MnF ２ , CeF ３ , Tb ４ O ７ , and TbF ３The third compound may be one of the following, and at least one selected from the group consisting of these is preferred. One type of third compound may be used alone, or two or more types may be used in combination. The third compound preferably contains Eu, and a portion of Eu may be substituted with Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, or the like. The other element substituted for a portion of Eu is considered to act as a co-activator. Eu mainly has divalent and trivalent energy levels. The nitride phosphor contains at least Eu ２＋ is preferably used as an activator.

[0053] Examples of the fourth compound containing Al include nitrides containing Al, hydrides containing Al, and halides containing Al. The halides containing Al are preferably fluorides. The fourth compound containing Al may be a metal made of Al or an alloy containing Al in which a part of Al is replaced with at least one element selected from the group consisting of Ga and In of Group 13 elements, and V, Cr, and Co of the fourth period. Examples of the fourth compound containing Al include AlN, AlH ３ , AlF ３ and LiAlH ４ The Al-containing compound may be used alone or in combination of two or more.

[0054] element M ４ The fifth compound containing the element M ４ Nitrides containing element M ４ hydrides containing element M ４ Element M ４ The halide containing the element M is preferably a fluoride. The fifth compound may be a hydrate. ４ The fifth compound containing the element M ４ Metal or element M represented by ４ The element M may be an alloy containing the element M, and a part of the element M may be replaced with another metal. ４ The fifth compound containing, specifically, GaN, InN, BN, GaF ３ , and InF ３The fifth compound may be a compound containing Ga, and at least one selected from the group consisting of these compounds is preferred. The fifth compound may be used alone or in combination of two or more.

[0055] element R ５ The sixth compound contains at least one element R selected from the group consisting of F, Cl, Br and I. ５ The sixth compound is a halide containing the element R ５ In addition to the above, a metal element may be contained, and the element M in the composition represented by the formula (1a) １ and / or element M ２ The element R may be a compound containing the element R. ５ The sixth compound is preferably a fluoride. Specifically, the sixth compound is LiF and SrF ２ The sixth compound is SrF ２ In this case, the first compound is an element M in the composition represented by the formula (1a). １ It is preferable to mix the sixth compound with the raw material mixture so as to satisfy the molar ratio. When the sixth compound is LiF, Li is likely to scatter during heat treatment, so it is preferable to add it so as to obtain a mixture in an amount of more than 3 mass% and not more than 9 mass% as a flux when the total amount of the first compound to the fifth compound is taken as 100 mass%. One type of the sixth compound may be used alone, or two or more types may be used in combination. The sixth compound is preferably LiF.

[0056] The sixth compound is added so that the sixth compound is in the range of more than 3 mass % to 9 mass % or less as a flux when the total amount of the first compound to the fifth compound is taken as 100 mass %, and mixed to obtain a raw material mixture. When the amount of the sixth compound added to the raw material mixture is within the above-mentioned range, the reaction of the raw materials, the first compound to the fifth compound, can be sufficiently promoted, crystal growth is promoted, and a nitride phosphor with few defects in the crystal structure and high crystallinity can be obtained. When the amount of the sixth compound added to the raw material mixture is within the above-mentioned range, in the composition represented by the formula (1), the element R derived from the flux per mol of the composition can be reduced. ５The sixth compound is preferably added so as to be in the range of 2.5% by mass or more and 8.5% by mass or less, and more preferably in the range of 3% by mass or more and 8% by mass or less, when the total amount of the first compound to the fifth compound is taken as 100% by mass.

[0057] The first to fifth compounds are weighed and mixed as raw materials so that the molar ratio of each element constituting the nitride phosphor contained in the first to fifth compounds satisfies the molar ratio of each element in 1 mole of the composition expressed by formula (1a). The raw material mixture can be obtained by adding the sixth compound as a flux to the first to fifth compounds so that the sixth compound is in the range of more than 3 mass% to 9 mass% or less, when the total amount of the first to fifth compounds is 100 mass%. The first to sixth compounds may be mixed using a mixer. Mixers that can be used include ball mills commonly used in industry, as well as vibration mills, roll mills, jet mills, and the like. However, it is preferable to mix the first to fifth compounds so that the molar ratio of each element constituting the nitride phosphor in the raw material mixture satisfies the molar ratio of each element in 1 mole of the composition expressed by formula (1a). The molar ratio of each element constituting the nitride phosphor contained in the raw material mixture is a theoretical composition ratio estimated from the blending ratios. The composition ratio (molar ratio) of each element constituting the nitride phosphor in the raw material mixture may differ from the theoretical composition ratio because each element may scatter during heat treatment or the crystal structure having the desired composition may decompose.

[0058] The method for producing a nitride phosphor includes heat-treating the obtained raw material mixture at a temperature of less than 1000° C. to obtain a heat-treated product.

[0059] As an apparatus for carrying out the heat treatment, for example, a gas pressure electric furnace can be used. In addition, for the heat treatment of the raw material mixture, carbon materials such as graphite, boron nitride (BN), alumina (Al ２ O ３ ), W, Mo or other materials can be used as the crucible, boat, etc.

[0060] The heat treatment temperature is less than 1000°C, and may be 999°C or less, preferably 500°C to 995°C, 600°C to 990°C, 700°C to 980°C, or 800°C to 960°C. When the raw material mixture is heat-treated at a temperature less than 1000°C, the halide contained in the raw material mixture or the halide used as a flux does not disperse, and the reaction between the compounds in the raw material mixture can be sufficiently promoted. The raw material mixture can be used to promote crystal growth, suppress the occurrence of defects in the crystal structure, and obtain a nitride phosphor with high crystallinity. When the heat treatment temperature exceeds 1000°C, the raw material mixture containing each element satisfying the composition represented by formula (1a) undergoes excessive reaction, causing the generated phosphor particles to melt and sinter, resulting in the generation of many hard, coarse particles. Nitride phosphors that generate many coarse particles may have reduced luminescence intensity or internal quantum efficiency. The heat treatment may be a two-stage heat treatment (multi-stage heat treatment) in which a first stage heat treatment is performed at 500°C or higher and 800°C or lower, and the temperature is gradually increased to perform a second stage heat treatment at a temperature higher than 800°C but lower than 1000°C.

[0061] In this manufacturing method, the heat treatment is preferably carried out in an atmosphere containing nitrogen gas. The nitrogen gas-containing atmosphere may contain, in addition to nitrogen gas, at least one selected from the group consisting of hydrogen, argon, carbon dioxide, carbon monoxide, ammonia, etc. The ratio of nitrogen gas in the heat treatment atmosphere is preferably 70% by volume or more, and more preferably 80% by volume or more.

[0062] In addition, in this manufacturing method, the heat treatment is preferably performed under a pressure of 0.2 MPa to 200 MPa. Nitride phosphors tend to decompose more easily at higher temperatures, but by using a pressurized atmosphere, decomposition is suppressed and higher luminescence intensity can be achieved. The pressure of the pressurized atmosphere is more preferably in the range of 0.2 MPa to 1.0 MPa, and even more preferably in the range of 0.8 MPa to 1.0 MPa, in terms of gauge pressure.

[0063] The heat treatment time may be appropriately selected depending on the heat treatment temperature, gas pressure, etc. The heat treatment time is, for example, preferably 1 hour or more and 100 hours or less, more preferably 2 hours or more and 80 hours or less, and even more preferably 3 hours or more and 70 hours or less.

[0064] In the method for producing a nitride phosphor, the heat-treated product obtained preferably contains a nitride phosphor having a composition represented by the formula (1) above.

[0065] The method for producing a nitride phosphor may include pulverizing the heat-treated product obtained after the heat treatment. Examples of the pulverizer include dry pulverizers such as a ball mill, a vibration mill, a hammer mill, a roll mill, and a jet mill. The heat-treated product may also be pulverized using a mortar and pestle.

[0066] The method for producing a nitride phosphor may include classifying the heat-treated product obtained after the heat treatment, or may include classifying the heat-treated product after pulverization. By classifying, the average particle size of the resulting nitride phosphor can be made equal to or greater than a predetermined value, and a nitride phosphor having a higher excitation light absorption rate and a higher luminescence intensity can be obtained. Specifically, classification is performed by sieving, gravity sedimentation classification in a solution, centrifugation, etc.

[0067] The present invention will be specifically explained below using examples, but the present invention is not limited to these examples. Each nitride phosphor in the examples, comparative examples, and reference examples described below is evaluated in one of the following ways. The results are shown in any of Tables 1 to 5. In the tables, the symbol "-" indicates that there is no numerical value for the corresponding item.

[0068] Emission Intensity, Emission Peak Wavelength, Full Width at Half Maximum, Internal Quantum Efficiency Each nitride phosphor in the Examples, Comparative Examples, and Reference Examples was irradiated with excitation light having an emission peak wavelength of 450 nm using a spectrofluorometer (QE-2000, manufactured by Otsuka Electronics Co., Ltd.) to measure its emission spectrum. The emission peak wavelength (nm), full width at half maximum (nm), and internal quantum efficiency (%) were determined from the obtained emission spectrum. For the phosphors of Reference Examples 1 to 3, the relative emission intensity (%) was measured, with the emission intensity at the emission peak wavelength of the phosphor of Reference Example 1, which had the lowest heat treatment temperature, taken as 100%. FIG. 4 shows the emission spectra of the nitride phosphors of Examples 1 to 4 and Comparative Example 1. FIG. 6 shows the emission spectra of the nitride phosphors of Examples 4 to 6 and Comparative Examples 2 to 4.

[0069] Composition ratio (molar ratio) of each element in nitride phosphor: The nitride phosphor was analyzed by ICP emission spectrometry using an inductively coupled plasma emission spectrometer (manufactured by Perkin Elmer). １ (Sr), element M ２ (Li), element M ３ (Eu), Al, element M ４ The composition ratio (molar ratio) of element R (Ga) in the nitride phosphors according to Examples 1 to 3, 5 and 6 and the nitride phosphors according to Comparative Examples 1 to 4 was measured. ５ (F) was analyzed by ion chromatography using an ion chromatography system (manufactured by Thermo Fisher Scientific) to identify the element R ５ The composition ratio (molar ratio) of element R (F) was measured. ５ Since the amount of (F) exceeded the upper limit of detection of the ion chromatography system, the element R was detected by a colorimetric method using a double beam spectrophotometer (Hitachi High-Tech Corporation). ５ The composition ratio (molar ratio) of (F) is measured.

[0070] Fluorescence Lifetime The fluorescence lifetime was measured using a fluorescence lifetime measurement device (Quantaurus-Tau, manufactured by Hamamatsu Photonics K.K.) by irradiating a nitride phosphor with excitation light having an emission peak wavelength of 442 nm, measuring the change in fluorescence intensity of the nitride phosphor over time from the point in time when the irradiation of the excitation light was blocked, and measuring the time required for the fluorescence intensity to decay to 1 / e (36.8%) of the intensity at the time when the excitation light was blocked, as the fluorescence lifetime (ns), assuming the fluorescence intensity at the time when the excitation light was blocked to be 100%.

[0071] Reflectance The reflectance and reflection spectrum of each nitride phosphor of the Reference Examples were measured using a spectrofluorometer (F-7100, manufactured by Hitachi High-Tech Corporation). Light from an excitation light source (halogen lamp) was irradiated onto each nitride phosphor sample at room temperature (25°C ± 5°C), and the reflection spectrum was measured in the wavelength range of 380 nm to 730 nm. A standard reflector (Spectralon (registered trademark), manufactured by Labsphere) was used as a reference sample, and the reflectance of the standard reflector at a wavelength of 450 nm was used as a reference. The reflectance of each nitride phosphor of Reference Examples 1 to 3 at a wavelength of 450 nm was calculated as a relative reflectance (%). The reflectance of each nitride phosphor of Reference Examples 1 to 3 at 730 nm is shown in Table 1.

[0072] X-ray diffraction patterns and peak intensities The X-ray diffraction patterns of the nitride phosphors according to Examples 1 to 4 and Comparative Example 1 were measured using a horizontal sample multipurpose X-ray diffractometer (Ultima IV, manufactured by Rigaku Corporation) and an X-ray source: CuKα radiation (λ=1.5418 Å, tube voltage 40 kV, tube current 40 mA). Figure 5 shows the X-ray diffraction patterns of the nitride phosphors according to Examples 1 to 4 and Comparative Example 1, as well as the peak intensities of SrLiAl ３ N ４ 1 is a powder X-ray diffraction pattern of a crystal structure having a composition represented by the formula: SrLiAl ３ N ４ The powder X-ray diffraction pattern of the crystalline structure having the composition represented by the formula (I) can be obtained from the International Center for Diffraction Data (ICDD).

[0073] Prior to the production of the nitride phosphors of the Examples, nitride phosphors of Reference Examples were obtained by changing the heat treatment temperature without adding flux to the raw material mixture.

[0074] Reference Example 1: The element M was added so as to satisfy the molar ratio in the composition represented by the formula (1a). １ Sr, element M ２ Li, element M ３ Eu, element M ４ was set to Ga. SrN ｕ (equivalent to u=2 / 3, Sr ２ N and SrN mixture, first compound), LiNH ２ (second compound), AlN (fourth compound), GaN (fifth compound), EuH ２ Each compound (third compound) is used as a raw material, and the raw materials are weighed and mixed in a glove box under an inert atmosphere so that the molar ratio of each element in each raw material is Sr:Li:Eu:Al:Ga = 0.99:1:0.01:2.5:0.5, to obtain a raw material mixture. In the raw material mixture, the molar ratio of each element constituting the nitride phosphor is also referred to as the molar ratio of the charged composition. In the raw material mixture, the molar ratio of each element constituting the nitride phosphor satisfies the molar ratio of each element in the composition represented by the formula (1a). The molar ratio of each element constituting the nitride phosphor in the raw material mixture is determined by the element M in the composition represented by the formula (1a). １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, variable s is 0.99 (s = 0.99), variable t is 1 (t = 1), variable x is 0.01 (x = 0.01), variable u is 0.17 (u = 0.17), the molar ratio of Al is the product of 0.83 and variable v, variable v is 3 (v = 3), and variable w is 4 (w = 4). Without adding flux, the raw material mixture is filled into a crucible, and heat-treated in a nitrogen gas atmosphere (100% by volume of nitrogen gas) at a gas pressure of 0.92 MPa as gauge pressure (1.02 MPa as absolute pressure) at a temperature of 900°C for 50 hours to obtain nitride phosphor particles, which are then pulverized and classified to obtain the nitride phosphor of Reference Example 1.

[0075] Reference Example 2 A nitride phosphor of Reference Example 2 was obtained in the same manner as Reference Example 1, except that the heat treatment temperature was set to 950° C. In Reference Example 2 and Reference Example 3 described later, the molar ratio of each element constituting the nitride phosphor in the raw material mixture satisfies the molar ratio in the composition represented by formula (1a). In Reference Example 2 and Reference Example 3 described later, the molar ratio of each element constituting the nitride phosphor in the raw material mixture is the same as the molar ratio of each element constituting the nitride phosphor in the raw material mixture of Reference Example 1.

[0076] Reference Example 3 A nitride phosphor of Reference Example 3 was obtained in the same manner as in Reference Example 1, except that the temperature of the heat treatment was set to 1050°C.

[0077]

[0078] The nitride phosphors according to Reference Examples 1 and 2 are heat-treated at a temperature of less than 1000°C, have a high reflectance of 60% or more at a wavelength of 730 nm, and efficiently emit fluorescence having an emission peak wavelength in the range of 620 nm to 655 nm. The nitride phosphors according to Reference Examples 1 and 2 have higher emission intensity and internal quantum efficiency than Reference Example 3. The nitride phosphor according to Reference Example 3 is heat-treated at a temperature exceeding 1000°C, has a low reflectance at 730 nm, and the emission intensity and internal quantum efficiency are also close to 0. When Ga is contained in the composition represented by formula (1), the relative emission intensity and internal quantum efficiency decrease when the heat treatment temperature exceeds 1000°C.

[0079] Example 1 M was added so as to satisfy the molar ratio in the composition represented by the formula (1a). １ Sr, M ２ Li, M ３ Eu, M ４ was set to Ga. SrN ｕ (equivalent to u=2 / 3, Sr ２ N and SrN mixture, first compound), LiNH ２ (second compound), AlN (fourth compound), GaN (fifth compound), EuH ２Each of the first compound to fifth compound (third compound) is used as a raw material, and the raw materials are weighed and mixed in a glove box under an inert atmosphere so that the molar ratio of each element in each raw material is Sr:Li:Eu:Al:Ga = 0.99:1:0.01:2.5:0.5. When the total amount of the first compound to fifth compound is 100 mass%, LiF (sixth compound) is added as a flux to the mixture of the first compound to fifth compound so that it becomes 3.5 mass%, thereby obtaining a raw material mixture. The molar ratio of each element constituting the nitride phosphor in the raw material mixture satisfies the molar ratio in the composition represented by the formula (1a). The molar ratio of each element constituting the nitride phosphor in the raw material mixture satisfies the molar ratio in the composition represented by the formula (1a), where element M １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, variable s is 0.99 (s = 0.99), variable t is 1 (t = 1), variable x is 0.01 (x = 0.01), variable u is 0.17 (u = 0.17), the molar ratio of Al is the product of 0.83 and variable v, variable v is 3 (v = 3), and variable w is 4 (w = 4). The raw material mixture is filled into a crucible, and heat-treated in a nitrogen gas atmosphere (100% by volume of nitrogen gas) at a gas pressure of 0.92 MPa (1.02 MPa in absolute pressure) at a temperature of 900 ° C for 50 hours to obtain nitride phosphor particles, which are then pulverized and classified to obtain a nitride phosphor having a composition represented by the formula (1). Table 2 shows the amount of flux added (mass%), the element R in the composition, and the amount of the element R in the composition. ５ The molar ratio (fluorine:F), emission peak wavelength, full width at half maximum, internal quantum efficiency, and fluorescence lifetime are listed.

[0080] Example 2 A nitride phosphor having a composition represented by formula (1) was obtained in the same manner as in Example 1, except that a raw material mixture was obtained by adding LiF as a flux so that the amount was 4 mass % when the total amount of compounds 1 to 5 was 100 mass %. In Example 2 and Examples 3 and 4 described below, the molar ratio of each element constituting the nitride phosphor in the raw material mixture satisfies the molar ratio in the composition represented by formula (1a) and has the same molar ratio as the molar ratio of each element constituting the nitride phosphor in the raw material mixture of Example 1.

[0081] Example 3 A nitride phosphor having a composition represented by the formula (1) was obtained in the same manner as in Example 1, except that a raw material mixture was obtained by adding LiF as a flux so that the amount was 5 mass % when the total amount of the first compound to the fifth compound was 100 mass %.

[0082] Example 4 A nitride phosphor having a composition represented by the formula (1) was obtained in the same manner as in Example 1, except that a raw material mixture was obtained by adding LiF as a flux so that the amount was 8 mass % when the total amount of the first compound to the fifth compound was 100 mass %.

[0083] Comparative Example 1 A nitride phosphor having a composition represented by formula (1) was obtained in the same manner as in Example 1, except that a raw material mixture was obtained by adding LiF as a flux so that the amount was 3 mass % when the total amount of compounds 1 to 5 was 100 mass %. The molar ratio of each element constituting the nitride phosphor in the raw material mixture of Comparative Example 1 satisfies the molar ratio in the composition represented by formula (1a) and is the same as the molar ratio of each element constituting the nitride phosphor in the raw material mixture of Example 1.

[0084] Table 2 shows the amount of flux (LiF) added when the total amount of the first to fifth compounds is 100% by mass, as well as the emission peak wavelength, full width at half maximum, internal quantum efficiency, and fluorescence lifetime of each nitride phosphor in the Examples and Comparative Examples. Table 3 shows the composition ratio (molar ratio) of each element constituting each nitride phosphor in the Examples and Comparative Examples, measured by the above-mentioned method. In the analyzed composition, the molar ratio of nitrogen (N) is 4 per mole of the composition.

[0085]

[0086]

[0087] The nitride phosphors according to Examples 1 to 4 have a composition represented by the formula (1), and in 1 mol of the composition represented by the formula (1), the element R ５ The variable y, which represents the molar ratio of fluorine (F), is in the range of more than 0.2 and 0.8 or less (0.2<y≦0.8), the fluorescence lifetime is longer than 750 ns (nanoseconds), the generation of defects in the crystal structure is suppressed, the crystal structure is stable, and the crystallinity is high.

[0088] The nitride phosphors according to Examples 1 to 4 contain the element R ５ The nitride phosphors according to Examples 1 to 4 contain LiF as a flux containing fluorine (F) in an amount of more than 3 mass % when the total amount of the first to fifth compounds is taken as 100 mass %. The nitride phosphors according to Examples 1 to 4 have emission peak wavelengths that are almost the same as those of the nitride phosphor of Comparative Example 1, but have higher internal quantum efficiency and longer fluorescence lifetimes than those of Comparative Example 1, and the generation of defects in the crystal structure is suppressed, resulting in a stable crystal structure.

[0089] The nitride phosphor according to Example 1 has a composition represented by the formula (1) in which the element M １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, and the element R ５ is F, the variable s is 0.98 (s = 0.98), the variable t is 1.06 (t = 1.06), the variable x is 0.0063 (x = 0.0063), the variable u is 0.16 (u = 0.16), the molar ratio of Al is the product of 0.84 and the variable v, the variable v is 2.75 (v = 2.75), the variable w is 4 (w = 4), and the variable y is 0.29 (y = 0.29).

[0090] The nitride phosphor according to Example 2 has a composition represented by the formula (1) in which the element M １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４is Ga, and the element R ５ is F, the variable s is 0.95 (s = 0.95), the variable t is 1.10 (t = 1.10), the variable x is 0.0058 (x = 0.0058), the variable u is 0.16 (u = 0.16), the molar ratio of Al is the product of 0.84 and the variable v, the variable v is 2.78 (v = 2.78), the variable w is 4 (w = 4), and the variable y is 0.36 (y = 0.36).

[0091] The nitride phosphor according to Example 3 has a composition represented by the formula (1) in which the element M １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, and the element R ５ is F, the variable s is 0.93 (s = 0.93), the variable t is 1.10 (t = 1.10), the variable x is 0.0068 (x = 0.0068), the variable u is 0.165 (u = 0.165), the molar ratio of Al is the product of 0.835 and the variable v, the variable v is 2.83 (v = 2.83), the variable w is 4 (w = 4), and the variable y is 0.42 (y = 0.42).

[0092] The nitride phosphor according to Example 4 has a composition represented by the formula (1) in which the element M １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, and the element R ５ is F, the variable s is 0.89 (s = 0.89), the variable t is 1.35 (t = 1.35), the variable x is 0.0077 (x = 0.0077), the variable u is 0.16 (u = 0.16), the molar ratio of Al is the product of 0.84 and the variable v, the variable v is 2.73 (v = 2.73), the variable w is 4 (w = 4), and the variable y is 0.79 (y = 0.79).

[0093] As shown in FIG. 4, the nitride phosphors according to Examples 1 to 4 have higher emission intensities than the nitride phosphor according to Comparative Example 1.

[0094] As shown in FIG. 5, the nitride phosphors according to Examples 1 to 4 and the nitride phosphor according to Comparative Example 1 are SrLiAl ３ N ４ and has a peak at the same position as that of the nitride phosphor represented by SrLiAl ３ N ４ It has a similar crystal structure to that of

[0095] The nitride phosphor according to Comparative Example 1 contains the element R in 1 mol of the composition represented by the formula (1). ５ The variable y representing the molar ratio of fluorine (F) is less than 0.2 (0.2>y), and the nitride phosphor according to Comparative Example 1 does not have the composition represented by the formula (1). ５ The flux (LiF) containing fluorine (F) is added in an amount of 3 mass % relative to 100 mass % of the total amount of the first to fifth compounds. ５ The variable y representing the molar ratio of fluorine (F) is less than 0.2 (0.2>y), and the nitride phosphor according to Comparative Example 1 does not have the composition of formula (1). The nitride phosphor according to Comparative Example 1 has a fluorescence lifetime of 750 ns or more, but the fluorescence lifetime is shorter than that of the nitride phosphors according to Examples 1 to 4, and it is presumed that defects exist in the crystal structure.

[0096] The nitride phosphor according to Comparative Example 1 has a composition represented by the formula (1) in which the element M １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, and the element R ５ is F, the variable s is 0.98 (s=0.98), the variable t is 1.02 (t=1.02), the variable x is 0.0061 (x=0.0061), the variable u is 0.165 (u=0.165), the molar ratio of Al is the product of 0.835 and the variable v, the variable v is 2.75 (v=2.75), the variable w is 4 (w=4), and the variable y is 0.17 (y=0.17). The nitride phosphor according to Comparative Example 1 has a composition represented by the formula (1) in which the element R ５ The variable y representing the molar ratio of F is less than 0.2 (0.2>y).

[0097] Example 5 A nitride phosphor having a composition represented by formula (1) was obtained in the same manner as in Example 4, except that a raw material mixture was obtained so that the molar ratio of each element in each raw material was Sr:Li:Eu:Al:Ga = 0.99:1:0.01:2.75:0.75. The elements constituting the nitride phosphor in the raw material mixture of Example 5 were the elements M in the composition represented by formula (1a). １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, the variable s is 0.99 (s=0.99), the variable t is 1 (t=1), the variable x is 0.01 (x=0.01), the variable u is 0.25 (u=0.25), the molar ratio of Al is the product of 0.75 and the variable v, the variable v is 3 (v=3), and the variable w is 4 (w=4).

[0098] Example 6 A nitride phosphor having a composition represented by formula (1) was obtained in the same manner as in Example 4, except that a raw material mixture was obtained so that the molar ratio of each element in each raw material was Sr:Li:Eu:Al:Ga = 0.99:1:0.01:2.0:1.0. The elements constituting the nitride phosphor in the raw material mixture of Example 6 were the elements M in the composition represented by formula (1a). １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, the variable s is 0.99 (s=0.99), the variable t is 1 (t=1), the variable x is 0.01 (x=0.01), the variable u is 0.33 (u=0.33), the molar ratio of Al is the product of 0.67 and the variable v, the variable v is 3 (v=3), and the variable w is 4 (w=4).

[0099] Comparative Example 2 A nitride phosphor is obtained in the same manner as in Example 4, except that a raw material mixture is obtained so that the molar ratio of each element in each raw material is Sr:Li:Eu:Al:Ga = 0.99:1:0.01:1.8:1.2. The elements constituting the nitride phosphor in the raw material mixture of Comparative Example 2 are represented by the formula (1a) above, and are the element M １ is Sr, and the element M２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, the variable s is 0.99 (s=0.99), the variable t is 1 (t=1), the variable x is 0.01 (x=0.01), the variable u is 0.4 (u=0.4), the molar ratio of Al is the product of 0.6 and the variable v, the variable v is 3 (v=3), and the variable w is 4 (w=4). ４ The molar ratio of element M ４ In the product of the variables u and v, which represent the molar ratio of the above, the variable u exceeds 0.38 (0.38<u), and the molar ratio in the composition represented by the formula (1a) is not satisfied.

[0100] Comparative Example 3 A nitride phosphor having a composition represented by formula (1) was obtained in the same manner as in Example 4, except that a raw material mixture was obtained so that the molar ratio of each element in each raw material was Sr:Li:Eu:Al:Ga = 0.99:1:0.01:1.5:1.5. The elements constituting the nitride phosphor in the raw material mixture of Comparative Example 3 were the element M in the composition represented by formula (1a). １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, the variable s is 0.99 (s=0.99), the variable t is 1 (t=1), the variable x is 0.01 (x=0.01), the variable u is 0.5 (u=0.5), the molar ratio of Al is the product of 0.5 and the variable v, the variable v is 3 (v=3), and the variable w is 4 (w=4). ４ The molar ratio of element M ４ In the product of the variables u and v, which represent the molar ratio of the above, the variable u exceeds 0.38 (0.38<u), and the molar ratio in the composition represented by the formula (1a) is not satisfied.

[0101] Comparative Example 4 (SLA) A nitride phosphor is obtained in the same manner as in Example 4, except that GaN is not used as a raw material and a raw material mixture is obtained so that the molar ratio of each element in each raw material is Sr:Li:Eu:Al:Ga = 0.99:1:0.01:3.0:0. The elements constituting the nitride phosphor in the raw material mixture of Comparative Example 4 are the element M in the composition represented by formula (1a). １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ The variable s is 0.99 (s=0.99), the variable t is 1 (t=1), the variable x is 0.01 (x=0.01), the variable u is 0 (u=0), the molar ratio of Al is the product of 1 and the variable v, the variable v is 3 (v=3), and the variable w is 4 (w=4). ４ The molar ratio of element M ４ In the product of the variables u and v representing the molar ratio, the variable u does not exceed 0 and is 0 (u=0), and the molar ratio in the composition represented by the formula (1a) is not satisfied.

[0102] Table 4 lists the molar ratio of Ga, emission peak wavelength, full width at half maximum, internal quantum efficiency, and fluorescence lifetime in the feed composition of each nitride phosphor according to the Examples and Comparative Examples. Table 5 lists the composition ratio (molar ratio) of each element constituting each nitride phosphor of the Examples and Comparative Examples, measured by the above-mentioned method. In the analyzed composition, the molar ratio of nitrogen (N) is 4 per mole of the nitride phosphor composition. Example 4 is listed in Tables 2 and 3, as well as Tables 4 and 5.

[0103]

[0104]

[0105] The nitride phosphors according to Examples 4 to 6 have a composition represented by the formula (1). The nitride phosphors according to Examples 4 to 6 contain an element R ５ The variable y, which represents the molar ratio of fluorine (F), is in the range of more than 0.2 but not more than 0.8 (0.2<y≦0.8), and the element M ４The variable u in the product of 3, which represents the molar ratio of Ga, and the variable u is greater than 0 and not greater than 0.38 (0<u≦0.38), and emits fluorescence having an emission peak wavelength in the range of 620 nm to 655 nm. The nitride phosphors according to Examples 4 to 6 have a fluorescence lifetime of 750 ns or more, suppressed generation of defects in the crystal structure, stable crystal structure with high crystallinity, and high internal quantum efficiency exceeding 65%.

[0106] As shown in FIG. 6, in the composition of the nitride phosphor, the element M ４ When the molar ratio of Ga increases, the emission peak wavelength in the emission spectrum tends to shift to the shorter wavelength side, and the emission intensity tends to decrease. The nitride phosphors according to Examples 4 to 6 emit fluorescence having an emission peak wavelength in the desired wavelength range of 620 nm to 655 nm, and have high emission intensity.

[0107] The nitride phosphor according to Example 5 has a composition represented by the formula (1) in which the element M １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, and the element R ５ is F, the variable s is 0.91 (s = 0.91), the variable t is 1.33 (t = 1.33), the variable x is 0.0050 (x = 0.0050), the variable u is 0.24 (u = 0.24), the molar ratio of Al is the product of 0.76 and the variable v, the variable v is 2.78 (v = 2.78), the variable w is 4 (w = 4), and the variable y is 0.67 (y = 0.67).

[0108] The nitride phosphor according to Example 6 has a composition represented by the formula (1) in which the element M １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, and the element R ５is F, the variable s is 0.91 (s = 0.91), the variable t is 1.43 (t = 1.43), the variable x is 0.0051 (x = 0.0051), the variable u is 0.306 (u = 0.306), the molar ratio of Al is the product of 0.694 and the variable v, the variable v is 2.81 (v = 2.81), the variable w is 4 (w = 4), and the variable y is 0.74 (y = 0.74).

[0109] The nitride phosphor according to Comparative Example 2 contains the element M ４ The molar ratio of Ga is high, the balance of the crystal structure is lost, and the element M ４ In the product of the variables u and v representing the molar ratio of the element M, the variable u is 0.36 or less, and the composition represented by the formula (1) is satisfied. ２ The variable t, which represents the molar ratio of Li to Li, exceeds 1.45, and does not have the composition represented by formula (1). The nitride phosphor according to comparative example 2 does not have the composition represented by formula (1), has a fluorescence lifetime of less than 750 ns, is unstable due to distortion or the like in the crystal structure, has low crystallinity, and reduces internal quantum efficiency. As shown in Figure 6, the nitride phosphor according to comparative example 2 has low crystallinity and reduces luminescence intensity.

[0110] The nitride phosphor according to Comparative Example 2 has a composition represented by the formula (1) in which the element M １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, and the element R ５ is F, the variable s is 1.04 (s=1.04), the variable t is 1.47 (t=1.47), the variable x is 0.0057 (x=0.0057), the variable u is 0.365 (u=0.365), the molar ratio of Al is the product of 0.635 and the variable v, the variable v is 2.85 (v=2.85), the variable w is 4 (w=4), and the variable y is 0.59 (y=0.59). The nitride phosphor according to Comparative Example 2 has a composition represented by the formula (1) in which the element M ２ The variable t representing the molar ratio of Li exceeds 1.45 (1.45<t), and the composition does not have the composition represented by the formula (1).

[0111] The nitride phosphor according to Comparative Example 3 contains the element M ４ The molar ratio of Ga is high, the balance of the crystal structure is lost, and the element M ４ In the product of the variables u and v, which represent the molar ratio of element M, the variable u is greater than 0.38, and ２ The variable t representing the molar ratio of Li exceeds 1.45, and the nitride phosphor according to Comparative Example 3 does not have the composition represented by Formula (1). The nitride phosphor according to Comparative Example 3 does not have the composition represented by Formula (1), and the fluorescence lifetime is less than 750 ns. The crystal structure is unstable due to distortion, etc., resulting in low crystallinity and a significant decrease in internal quantum efficiency. As shown in Figure 6, the nitride phosphor according to Comparative Example 3 has low crystallinity and a significant decrease in emission intensity.

[0112] The nitride phosphor according to Comparative Example 3 has a composition represented by the formula (1) in which the element M １ is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ is Ga, and the element R ５ is F, the variable s is 0.93 (s=0.93), the variable t is 1.49 (t=1.49), the variable x is 0.0062 (x=0.0062), the variable u is 0.45 (u=0.45), the molar ratio of Al is the product of 0.55 and the variable v, the variable v is 3.03 (v=3.03), the variable w is 4 (w=4), and the variable y is 0.62 (y=0.62). The nitride phosphor according to Comparative Example 3 has a composition represented by the formula (1) in which the element M ２ The variable t representing the molar ratio of Li is greater than 1.45 (1.45<t), and the element M ４ In the product of the variables u and v that represent the molar ratio of Ga, the variable u exceeds 0.38 (0.38<u), and the composition does not have the composition represented by the formula (1).

[0113] The nitride phosphor according to Comparative Example 4 contains the element M ４ The nitride phosphor does not contain Ga, and the emission peak wavelength exceeds 650 nm.

[0114] The nitride phosphor according to Comparative Example 4 has a composition represented by the formula (1) in which the element M １is Sr, and the element M ２ is Li, and the element M ３ is Eu, and the element M ４ does not contain element R ５ is F, the variable s is 0.92 (s=0.92), the variable t is 1.04 (t=1.04), the variable x is 0.0064 (x=0.0064), the variable u is 0 (u=0), the molar ratio of Al is the product of 1 and the variable v, the variable v is 2.88 (v=2.88), the variable w is 4 (w=4), and the variable y is 0.34 (y=0.34). The nitride phosphor according to Comparative Example 4 has a composition represented by the formula (1) in which the element M ４ In the product of the variables u and v representing the molar ratio of Ga, the variable u is 0 (u=0), and the composition does not have the composition represented by the formula (1).

[0115] Embodiments according to the present disclosure include the following nitride phosphor, light emitting device, and method for manufacturing the nitride phosphor.

[0116] [Item 1] A nitride phosphor having a composition represented by the following formula (1): M １ ｓ M ２ ｔ M ３ ｘ (Al １－ｕ M ４ ｕ ) ｖ N ｗ R ５ ｙ (1) (In the above formula (1), M １ is at least one element selected from the group consisting of Sr, Ca, Ba, and K, and M ２ is at least one element selected from the group consisting of Li, Na, and Mg, and M ３ is at least one element selected from the group consisting of Eu, Mn, Ce, and Tb, and M ４ is at least one element selected from the group consisting of Ga, In, and B, and R ５is at least one element selected from the group consisting of F, Cl, Br and I, and s, t, u, v, w, x and y respectively satisfy 0.7≦s≦1.3, 0.7≦t≦1.45, 0<u≦0.38, 2.4≦v≦3.7, 3.0≦w≦5.0, 0<x≦0.2, 0.2<y≦0.8. [Item 2] The nitride phosphor according to Item 1, wherein in formula (1), u and x satisfy 0.01≦u≦0.33 and 0.001≦x≦0.1. [Item 3] In formula (1), M １ contains Sr, and M ２ contains Li, and M ３ contains Eu, and M ４ Item 4. The nitride phosphor according to item 1 or 2, wherein R ５ [Item 5] The nitride phosphor according to any one of Items 1 to 3, wherein M contains F. １ is Sr, and M ３ is Eu, and M ４ [Item 6] In the formula (1), R is Ga. ５ [Item 7] The nitride phosphor according to any one of Items 1 to 5, wherein in the formula (1), M is F. ３ [Item 8] The nitride phosphor according to any one of Items 1 to 6, wherein M is Eu, and the nitride phosphor has a fluorescence lifetime of 750 ns or more. [Item 9] A light emitting device comprising the nitride phosphor according to any one of Items 1 to 8, and a light emitting element having an emission peak wavelength in the range of 300 nm to 500 nm, and irradiating the nitride phosphor with excitation light. [Item 10] At least one element M selected from the group consisting of Sr, Ca, Ba, and K. １ and at least one element M selected from the group consisting of Li, Na, and Mg. ２ and at least one element M selected from the group consisting of Eu, Mn, Ce, and Tb. ３ a third compound containing Al; a fourth compound containing at least one element M selected from the group consisting of Ga, In, and B;４ and at least one element R selected from the group consisting of F, Cl, Br, and I. ５ and a sixth compound containing the element M, wherein at least one compound of the first to fifth compounds is a nitride; １ and an element M contained in the second compound. ２ and an element M contained in the third compound. ３ and Al contained in the fourth compound, and element M contained in the fifth compound. ４ and M are mixed together so as to satisfy the molar ratio in the composition represented by the following formula (1a), and when the total amount of the first compound to the fifth compound is taken as 100 mass%, the sixth compound is added as a flux so as to be more than 3 mass% to 9 mass% or less to obtain a raw material mixture, and heat-treating the raw material mixture at a temperature less than 1000°C to obtain a heat-treated product. １ ｓ M ２ ｔ M ３ ｘ (Al １－ｕ M ４ ｕ ) ｖ N ｗ (1a) (In the formula (1a), s, t, u, v, w, and x satisfy 0.7≦s≦1.3, 0.7≦t≦1.45, 0<u≦0.38, 2.4≦v≦3.7, 3.0≦w≦5.0, and 0<x≦0.2, respectively.) [Item 11] A method for producing a nitride phosphor according to Item 10, wherein the heat-treated product contains a nitride phosphor having a composition represented by the following formula (1): M １ ｓ M ２ ｔ M ３ ｘ (Al １－ｕ M ４ ｕ ) ｖ N ｗ R ５ ｙ(1) (In the formula (1), s, t, u, v, w, x, and y satisfy 0.7≦s≦1.3, 0.7≦t≦1.45, 0<u≦0.38, 2.4≦v≦3.7, 3.0≦w≦5.0, 0<x≦0.2, and 0.2<y≦0.8, respectively.) [Item 12] A method for producing a nitride phosphor according to Item 10 or 11, wherein the heat treatment is performed at a temperature in the range of 500° C. or higher and 995° C. or lower. [Item 13] A method for producing a nitride phosphor according to any one of items 10 to 12, wherein the heat treatment is performed in an atmosphere containing nitrogen gas, and the heat treatment is performed at a pressure in the range of 0.2 MPa or higher and 200 MPa or lower.

[0117] The nitride phosphor according to the present disclosure has few defects, high crystallinity, a long fluorescent lifetime, and emits light with high internal quantum efficiency, and light emitting devices using this nitride phosphor can be suitably used as a light source for illumination, etc. In particular, the nitride phosphor can be suitably used as a light source for illumination that uses a light emitting diode as an excitation light source and has extremely excellent light emission characteristics, as well as for LED displays, backlight sources for liquid crystal displays, etc.

[0118] 10: Light-emitting element, 11: Semiconductor element, 20: First lead, 30: Second lead, 40: Molded body, 42: Resin part, 50, 51: Wavelength conversion member, 52: Wavelength conversion member, 53: Light-transmitting body, 60: Wire, 61: Conductive member, 70: Phosphor, 71: First phosphor, 72: Second phosphor, 80: Adhesive layer, 90: Covering member, 100, 200: Light-emitting device.

Claims

1. A nitride phosphor having a composition represented by the following formula (1): M １ ｓ M ２ ｔ M ３ ｘ (Al １－ｕ M ４ ｕ ) ｖ N ｗ R ５ ｙ (1) (In the above formula (1), M １ is at least one element selected from the group consisting of Sr, Ca, Ba, and K, and M ２ is at least one element selected from the group consisting of Li, Na, and Mg, and M ３ is at least one element selected from the group consisting of Eu, Mn, Ce, and Tb, and M ４ is at least one element selected from the group consisting of Ga, In, and B, and R ５ is at least one element selected from the group consisting of F, Cl, Br, and I, and s, t, u, v, w, x, and y satisfy the following conditions: 0.7≦s≦1.3, 0.7≦t≦1.45, 0<u≦0.38, 2.4≦v≦3.7, 3.0≦w≦5.0, 0<x≦0.2, 0.2<y≦0.8, respectively.

2. The nitride phosphor according to claim 1, wherein in said formula (1), u and x satisfy 0.01≦u≦0.33 and 0.001≦x≦0.

1.

3. In the above formula (1), M １ contains Sr, and M ２ contains Li, and M ３ contains Eu, and M ４ The nitride phosphor according to claim 1 or 2, wherein contains Ga.

4. In the formula (1), R ５ The nitride phosphor according to claim 1 , wherein 5. In the above formula (1), M １ is Sr, and M ３ is Eu, and M ４ The nitride phosphor according to claim 1 , wherein is Ga.

6. In the formula (1), R ５ The nitride phosphor according to claim 1 , wherein is F.

7. The nitride phosphor is a compound represented by the formula (1): ３ The nitride phosphor according to claim 1 , wherein is Eu, and the nitride phosphor has a fluorescence lifetime of 750 ns or longer.

8. The nitride phosphor according to any one of claims 1 to 7, wherein the nitride phosphor has a fluorescence lifetime of 900 ns or less.

9. A light emitting device comprising the nitride phosphor according to any one of claims 1 to 8 and a light emitting element having an emission peak wavelength in the range of 300 nm to 500 nm, which irradiates the nitride phosphor with excitation light.

10. At least one element M selected from the group consisting of Sr, Ca, Ba, and K １ and at least one element M selected from the group consisting of Li, Na, and Mg. ２ and at least one element M selected from the group consisting of Eu, Mn, Ce, and Tb. ３ a third compound containing Al; a fourth compound containing at least one element M selected from the group consisting of Ga, In, and B; ４ and at least one element R selected from the group consisting of F, Cl, Br, and I. ５ and a sixth compound containing the element M, wherein at least one compound from the first compound to the fifth compound is a nitride; １ and an element M contained in the second compound. ２ and an element M contained in the third compound. ３ and Al contained in the fourth compound, and element M contained in the fifth compound. ４ and M are mixed together so as to satisfy the molar ratio in the composition represented by the following formula (1a), and when the total amount of the first compound to the fifth compound is taken as 100 mass%, the sixth compound is added as a flux so as to be more than 3 mass% to 9 mass% or less to obtain a raw material mixture, and heat-treating the raw material mixture at a temperature less than 1000°C to obtain a heat-treated product. １ ｓ M ２ ｔ M ３ ｘ (Al １－ｕ M ４ ｕ ) ｖ N ｗ (1a) (In the formula (1a), s, t, u, v, w, and x satisfy the following conditions: 0.7≦s≦1.3, 0.7≦t≦1.45, 0<u≦0.38, 2.4≦v≦3.7, 3.0≦w≦5.0, and 0<x≦0.2, respectively.) 11. The method for producing a nitride phosphor according to claim 10, wherein the heat-treated product contains a nitride phosphor having a composition represented by the following formula (1): M １ ｓ M ２ ｔ M ３ ｘ (Al １－ｕ M ４ ｕ ) ｖ N ｗ R ５ ｙ (1) (In the formula (1), s, t, u, v, w, x, and y satisfy the following relationships: 0.7≦s≦1.3, 0.7≦t≦1.45, 0<u≦0.38, 2.4≦v≦3.7, 3.0≦w≦5.0, 0<x≦0.2, 0.2<y≦0.8, respectively.) 12. The method for producing a nitride phosphor according to claim 10 or 11, wherein the temperature of the heat treatment is in the range of 500°C or higher and 995°C or lower.

13. The method for producing a nitride phosphor according to any one of claims 10 to 12, wherein the heat treatment is carried out in an atmosphere containing nitrogen gas, and the pressure of the heat treatment is in the range of 0.2 MPa to 200 MPa.

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