Phosphor and its manufacturing method

Abstract

To provide a nitride-based fluorescent material that can exhibit higher emission intensity.SOLUTION: A fluorescent material includes a nitride fluorescent material comprising La, Ce, Si, and N; and a first phosphorus compound disposed on a surface of the nitride fluorescent material. The first phosphorus compound includes at least one selected from the group consisting of lanthanum phosphate, lanthanum hydrogen phosphate, and hydrates thereof. A content of phosphorus atoms in the fluorescent material is 0.07 mass% or higher and 0.8 mass% or lower.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to phosphors and methods for producing the same. [Background technology]

[0002] As a light emitting device, for example, there is a light emitting device that combines a blue LED (Light Emitting Diode) chip or a blue LD (Laser Diode) with a yellow phosphor. As a yellow phosphor, for example, La3Si6N described in Patent Document 1 is used. 11 A nitride-based phosphor having a composition represented by the formula: Ce is known. Patent Document 1 proposes a production method in which a nitride-based phosphor is heat-treated in the presence of a fluorine-containing substance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-112589 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of one aspect of the present disclosure is to provide a nitride-based phosphor capable of exhibiting higher luminescence intensity and a method for producing the same. [Means for solving the problem]

[0005] The first aspect is a phosphor comprising a nitride phosphor containing lanthanum (La), cerium (Ce), silicon (Si), and nitrogen (N), and a first phosphorus compound present on the surface of the nitride phosphor. The first phosphorus compound comprises at least one selected from the group consisting of lanthanum phosphate, lanthanum hydrogen phosphate, and hydrates thereof. The phosphor contains phosphorus atoms in an amount of 0.07% by mass or more and 0.8% by mass or less.

[0006] The second aspect is a method for producing a phosphor, which includes heat-treating a nitride phosphor having a composition represented by the following formula (1) at a temperature of 90°C or higher and 400°C or lower in the presence of a second phosphorus compound of 0.1% by mass or more and 47% by mass or less with respect to the nitride phosphor and liquid or gaseous water. La p Ce s M 1 q M 2 r N t (1)

[0007] In formula (1), M 1 represents at least one selected from the group consisting of rare earth elements other than La and Ce, includes at least one selected from the group consisting of at least Y, Gd, and Lu, and M 2 represents at least one selected from the group consisting of Si, Ge, B, Al, and Ga, includes at least Si, and p, q, r, s, and t satisfy 2.7 ≤ p + q + s ≤ 3.3, 0 ≤ q ≤ 1.2, 5.4 ≤ r ≤ 6.6, 10 ≤ t ≤ 12, and 0 < s ≤ 1.2.

[0008] The third aspect is a light-emitting device including a light-emitting element having an emission peak wavelength within a wavelength range of 350 nm or more and 500 nm or less, and the phosphor of the first aspect excited by the light-emitting element.

Effects of the Invention

[0009] According to one aspect of the present disclosure, it is possible to provide a nitride-based phosphor capable of exhibiting higher emission intensity and a method for producing the same.

Brief Description of the Drawings

[0010] [Figure 1A] It is a plan view of the wavelength conversion member seen from the main surface side. [Figure 1B] It is a side view of the wavelength conversion member seen from the side, and is a cross-sectional view showing a part thereof in an enlarged manner. [Figure 2] It is a schematic configuration diagram showing an example of a light-emitting device and a diagram showing a part of the wavelength conversion member thereof in an enlarged manner. [Figure 3]10A and 10B are schematic configuration diagrams showing another example of a light emitting device and enlarged views showing a part of a wavelength conversion member thereof. [Figure 4] FIG. 2 is a diagram showing the emission spectrum of a phosphor. [Figure 5] FIG. 10 is a diagram showing a change in the emission intensity of light emitted from a wavelength conversion member with respect to a change in the output density of a laser diode. DETAILED DESCRIPTION OF THE INVENTION

[0011] As used herein, the term "process" refers not only to an independent process, but also to processes that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. Furthermore, when multiple substances corresponding to each component are present in the composition, the content of each component refers to the total amount of those multiple substances present in the composition, unless otherwise specified. Furthermore, the upper and lower limits of the numerical ranges described herein can be arbitrarily selected and combined from the numerical values ​​exemplified as numerical ranges. In this specification, the relationship between color names and chromaticity coordinates, the relationship between light wavelength ranges and monochromatic light color names, etc., conforms to JIS Z8110. The half-width of a phosphor refers to the wavelength width (full width at half maximum; FWHM) of the emission spectrum of the phosphor where the emission intensity is 50% of the maximum emission intensity. Hereinafter, embodiments of the present invention will be described in detail. However, the following embodiments are intended to exemplify phosphors and methods for producing the same in order to embody the technical concept of the present invention. The present invention is not limited to the phosphors and methods for producing the same.

[0012] phosphor The phosphor includes a nitride phosphor containing lanthanum (La), cerium (Ce), silicon (Si), and nitrogen (N), and a first phosphorus compound present on the surface of the nitride phosphor. The first phosphorus compound includes at least one selected from the group consisting of lanthanum phosphate, lanthanum hydrogen phosphate, and hydrates thereof. The phosphor contains phosphorus atoms in an amount of 0.07% by mass or more and 0.8% by mass or less.

[0013] Phosphors containing nitride phosphors having a predetermined amount of a specific phosphorus compound on their surface can achieve high brightness. This is presumably because by placing a phosphorus compound with a low refractive index on the surface of a nitride phosphor with a high refractive index, the difference in refractive index between the phosphorus compound and the air layer becomes smaller than the difference in refractive index between the nitride phosphor and the air layer, thereby improving light extraction efficiency.

[0014] The nitride phosphor contains at least one rare earth element M selected from the group consisting of rare earth elements other than La and Ce. 1 The nitride phosphor may further contain a rare earth element M other than La and Ce in its composition. 1 may contain at least one selected from the group consisting of at least Y, Gd, and Lu, may contain at least one of Y and Gd, or may contain at least Y.

[0015] In the composition of the nitride phosphor, when the number of moles of Si is, for example, 6, the ratio of the number of moles of La may be, for example, 0.5 or more and 3.05 or less. The ratio of the number of moles of La may be preferably 1.2 or more, or 2.0 or more, and preferably 2.9 or less, or 2.2 or less. In the composition of the nitride phosphor, when the number of moles of Si is 6, the ratio of the number of moles of Ce may be 1.2 or less. The ratio of the number of moles of Ce may be preferably 0.15 or more, or 0.30 or more, and preferably 1.0 or less, or 0.8 or less. In the composition of the nitride phosphor, when the number of moles of Si is 6, the ratio of the number of moles of M 1 The ratio of the number of moles of M may be, for example, 0 or more and 1.2 or less. 1 The molar ratio of nitrogen to silicon may be preferably 0.3 or more, or 0.5 or more, and preferably 1.0 or less, or 0.8 or less. In the composition of the nitride phosphor, when the molar number of Si is 6, the molar ratio of nitrogen to silicon may be, for example, 10 or more and 12 or less, preferably 10.5 or more, or 10.8 or more, and preferably 11.5 or less, or 11.3 or less.

[0016] The composition of the nitride phosphor is, for example, when the mole number of Si is 6, La, Ce and M1 The ratio of the total number of moles may be, for example, 2.7 or more and 3.3 or less. La, Ce, and M 1 The ratio of the total moles may preferably be 2.8 or more, or 2.9 or more, and may preferably be 3.2 or less, or 3.1 or less.

[0017] In the composition of the nitride phosphor, part of Si may be substituted with a Group 13 or Group 14 element containing at least one selected from the group consisting of Ge, B, Al, and Ga.

[0018] The nitride phosphor may have, for example, a composition represented by the following formula (1). La p Ce s M 1 q M 2 r N t (1)

[0019] In formula (1), M 1 represents at least one selected from the group consisting of rare earth elements other than La and Ce, and may contain at least one selected from the group consisting of at least Y, Gd, and Lu. M 2 represents at least one selected from the group consisting of Si, Ge, B, Al, and Ga, and contains at least Si. p, q, r, s, and t satisfy 2.7 ≦ p + q + s ≦ 3.3, 0 ≦ q ≦ 1.2, 5.0 ≦ r ≦ 6.6, 10 ≦ t ≦ 12, 0 < s ≦ 1.2.

[0020] In formula (1), M 1 may contain at least one of Y and Gd, and may contain at least Y. In this case, in formula (1), p, q, r, s, and t preferably satisfy 2.8 ≦ p + q + s ≦ 3.2, 0.3 ≦ q ≦ 1.0, 5.5 ≦ r ≦ 6.5, 10.5 ≦ t ≦ 11.5, 0.15 ≦ s ≦ 1.0, or 2.9 ≦ p + q + s ≦ 3.1, 0.5 ≦ q ≦ 0.8, 5.8 ≦ r ≦ 6.2, 10.8 ≦ t ≦ 11.3, 0.3 ≦ s ≦ 0.8.

[0021] The composition of the nitride phosphor can be determined by, for example, inductively coupled plasma (ICP) emission spectroscopy for metal elements, and by, for example, an oxygen / nitrogen / hydrogen analyzer for nitrogen atoms (N).

[0022] The phosphor has a first phosphorus compound disposed on the surface of a nitride phosphor. The first phosphorus compound may be physically disposed on the surface of the nitride phosphor by van der Waals forces or the like, or may be chemically bonded to the surface of the nitride phosphor by covalent bonds, ionic bonds, or the like. The first phosphorus compound includes at least one selected from the group consisting of lanthanum phosphate, lanthanum hydrogen phosphate, and hydrates thereof. The first phosphorus compound may include one type alone or a combination of two or more types. It is preferable that the entire surface of the nitride phosphor is completely covered with a film or particles containing the first phosphorus compound. However, a portion of the film of the first phosphorus compound may be partially missing, or a portion of the surface of the nitride phosphor may be exposed to an extent that the effect can be achieved. The coverage rate of the phosphor with the first phosphorus compound may be, for example, 50% or more, preferably 80% or more, or 90% or more. The coverage rate of the phosphor with the first phosphorus compound is calculated as the ratio of the area covered by the first phosphorus compound to the surface area of ​​the nitride phosphor particles.

[0023] Lanthanum phosphate and its hydrates include LaPO4·nH2O, LaP3O9·nH2O, and LaP5O 14 nH2O, La2P6O 18 , La2P6O 18 ·nH2O, La3PO7 · nH2O, La5P6O 22.5 nH2O, La5P 10 O 36.5 nH2O, La7P3O 18·nH2O, etc. Furthermore, examples of lanthanum hydrogen phosphate and its hydrates include LaHP2O7·nH2O, LaH2PO4·nH2O, LaH3P2O6·nH2O, La(H2PO2)3·nH2O, La(H2PO3)3·nH2O, La2(HPO3)3·nH2O, La4H3(PO4)5·nH2O, etc.

[0024] The content of the first phosphorus compound in the phosphor may be, for example, 0.07% by mass or more and 0.8% by mass or less, in terms of the phosphorus atom content. The phosphorus atom content in the phosphor may preferably be 0.08% by mass or more, 0.1% by mass or more, 0.2% by mass or more, or 0.3% by mass or more, and may preferably be 0.7% by mass or less, or 0.5% by mass or less. When the phosphorus atom content in the phosphor is within the above range, the luminous intensity tends to be further improved. The phosphorus atom content in the phosphor can be determined, for example, by inductively coupled plasma (ICP) optical emission spectroscopy.

[0025] The phosphor may further contain oxygen atoms and hydrogen atoms. The oxygen atoms and hydrogen atoms may be contained as a first phosphorus compound, as hydroxyl groups on the surface of the nitride phosphor, or as part of the composition of the nitride phosphor. The content of oxygen atoms contained in the phosphor may be, for example, 0.6% by mass or more. The content of oxygen atoms in the phosphor may preferably be 0.7% by mass or more, 0.8% by mass or more, 1.0% by mass or more, or 1.2% by mass or more, and may preferably be 4% by mass or less, 3.5% by mass or less, or 2% by mass or less. The content of oxygen atoms in the phosphor can be determined, for example, using an oxygen / nitrogen / hydrogen analyzer.

[0026] The content of hydrogen atoms in the phosphor may be, for example, 0.02% by mass or more. The content of hydrogen atoms in the phosphor may be preferably 0.03% by mass or more, or 0.05% by mass or more, and may be preferably 0.10% by mass or less, or 0.08% by mass or less. The content of hydrogen atoms in the phosphor can be determined, for example, by an oxygen / nitrogen / hydrogen analyzer.

[0027] Since the phosphor contains a nitride phosphor and a first phosphorus compound, the phosphor composition may have a ratio of the number of moles of P to the number of moles of Si of, for example, 6, of, for example, 0.15 or less. The ratio of the number of moles of P may preferably be 0.01 or more, 0.02 or more, or 0.05 or more, and may also preferably be 0.12 or less, or 0.1 or less. Furthermore, since the phosphor may further contain oxygen atoms, the phosphor composition may have a ratio of the number of moles of O to the number of moles of Si of, for example, 6, of, for example, 1.5 or less. The ratio of the number of moles of O may preferably be 0.25 or more, 0.3 or more, or 0.5 or more, and may also preferably be 1.4 or less, or 1.2 or less. Furthermore, since the phosphor may further contain hydrogen atoms, the phosphor composition may have a ratio of the number of moles of H to the number of moles of Si of, for example, 6, of, for example, 0.75 or less. The ratio of the number of moles of H may be preferably 0.15 or more, 0.2 or more, or 0.3 or more, and may be preferably 0.6 or less, or 0.5 or less.

[0028] A phosphor containing a nitride phosphor and a first phosphorus compound present on the surface of the nitride phosphor may have a composition represented by, for example, formula (2) below as the entire phosphor, including the composition of the nitride phosphor and the first phosphorus compound mainly present on its surface. La p Ce s M 1 q M 2 r N t P x O y H z (2)

[0029] In formula (2), M 1 represents at least one element selected from the group consisting of rare earth elements other than La and Ce, and may include at least one element selected from the group consisting of Y, Gd, and Lu. 2represents at least one selected from the group consisting of Si, Ge, B, Al, and Ga, and may contain at least Si. p, q, r, s, t, x, y, and z may satisfy 2.7 ≦ p + q + s ≦ 3.3, 0 ≦ q ≦ 1.2, 5.4 ≦ r ≦ 6.6, 9.5 ≦ t ≦ 11.5, 0 < s ≦ 1.2, 0 < x ≦ 0.15, 0 < y ≦ 1.5, and 0 < z ≦ 0.75.

[0030] In formula (2), M 1 may contain at least one of Y and Gd, and may contain at least Y. Further, in formula (2), p, q, r, s, t, x, y, and z may preferably satisfy 2.8 ≦ p + q + s ≦ 3.2, 0.3 ≦ q ≦ 1.0, 5.5 ≦ r ≦ 6.5, 10.5 ≦ t ≦ 11.5, 0.15 ≦ s ≦ 1.0, 0.01 ≦ x ≦ 0.15, 0.25 ≦ y ≦ 1.5, 0.15 ≦ z ≦ 0.75, or 2.9 ≦ p + q + s ≦ 3.1, 0.5 ≦ q ≦ 0.8, 5.8 ≦ r ≦ 6.2, 10.8 ≦ t ≦ 11.3, 0.3 ≦ s ≦ 0.8, 0.02 ≦ x ≦ 0.12, 0.3 ≦ y ≦ 1.4, 0.2 ≦ z ≦ 0.6.

[0031] The particle size distribution of the phosphor may show a single-peak particle size distribution from the viewpoint of emission intensity. The median particle size (Dm) of the phosphor may be, for example, 5 μm or more and 40 μm or less. The median particle size of the phosphor may preferably be 10 μm or more, or 15 μm or more, and may preferably be 35 μm or less, or 30 μm or less. The median particle size of the phosphor is calculated as the particle size corresponding to 50% of the volume accumulation from the smaller diameter side in the volume-based particle size distribution. Further, the volume-based particle size distribution is measured using, for example, a laser diffraction particle size distribution measuring device.

[0032] The phosphor may absorb light with a wavelength of, for example, 350 nm or more and 500 nm or less, and have an emission peak wavelength in the wavelength range of, for example, 520 nm or more and 620 nm or less. The lower limit of the emission peak wavelength of the nitride phosphor may preferably be 525 nm or more, or 530 nm or more. The upper limit of the emission peak wavelength of the nitride phosphor may preferably be 615 nm or less, or 610 nm or less. The half-width in the emission spectrum of the nitride phosphor may be, for example, 100 nm or more, preferably 105 nm or more, or 110 nm or more. The upper limit of the half-width may be, for example, 150 nm or less, preferably 140 nm or less, or 130 nm or less.

[0033] Phosphor manufacturing method The method for producing the phosphor includes a heat treatment step of heat treating a nitride phosphor containing lanthanum (La), cerium (Ce), silicon (Si), and nitrogen atoms (N) at a temperature of 90°C or higher and 400°C or lower in the presence of a second phosphorus compound in an amount of 0.1% by mass or higher and 47% by mass or lower relative to the nitride phosphor, and liquid or gaseous water.

[0034] A phosphor with improved luminescence intensity can be obtained by heat-treating a nitride phosphor having a specific composition at a predetermined temperature in the presence of a predetermined amount of a second phosphorus compound and water. This can be thought of, for example, as follows: When a nitride phosphor is heat-treated in the presence of water, water or water vapor acts on the surface of the nitride phosphor, forming, for example, hydroxyl groups. The nitride phosphor with the formed hydroxyl groups reacts with the second phosphorus compound through heat treatment, forming a first phosphorus compound on the surface of the nitride phosphor. It can be considered that the formed first phosphorus compound adheres to the surface of the nitride phosphor, thereby improving the luminescence intensity of the phosphor. Here, in this specification, "water" refers to water in the broad sense as a substance (e.g., hydrogen hydroxide), and its state may be liquid (so-called water) or gas (e.g., water vapor).

[0035] The nitride phosphor to be subjected to the heat treatment step may be prepared by purchasing, or may be prepared by manufacturing a nitride phosphor having desired properties. The method for manufacturing the nitride phosphor will be described later. Details of the nitride phosphor to be subjected to the heat treatment step are as described above, and the same applies to preferred embodiments. In one embodiment, the nitride phosphor may have a composition represented by the above formula (1).

[0036] In the heat treatment step, the nitride phosphor is heat-treated at a temperature of 90°C to 400°C in the presence of a second phosphorus compound in an amount of 0.1% by mass to 47% by mass relative to the nitride phosphor and liquid or gaseous water to obtain a heat-treated product. The obtained heat-treated product may contain a desired phosphor. In the heat treatment step, a first phosphorus compound containing at least one selected from the group consisting of lanthanum phosphate, lanthanum hydrogen phosphate, and hydrates thereof may be formed on the surface of the nitride phosphor from the second phosphorus compound and liquid or gaseous water. The first phosphorus compound may be formed by reaction of water and the second phosphorus compound with the nitride phosphor.

[0037] The second phosphorus compound used in the heat treatment step may be, for example, a water-soluble phosphate. Specific examples of the second phosphorus compound include water-soluble phosphates such as phosphoric acid, phosphorus oxide, ammonium phosphate, alkali metal phosphate, and alkaline earth metal phosphate. The second phosphorus compound may contain at least one compound selected from the group consisting of phosphoric acid, phosphorus oxide, ammonium phosphate, alkali metal phosphate, and alkaline earth metal phosphate, or may contain at least one compound selected from the group consisting of phosphoric acid and ammonium phosphate, or may contain at least an ammonium phosphate. Here, "water-soluble" means that the solubility in 100 g of water at 25°C is 10 g or more.

[0038] Examples of the phosphoric acid in the second phosphorus compound include pyrophosphoric acid, metaphosphoric acid, and orthophosphoric acid. Examples of phosphorus oxide include diphosphorus pentoxide. Examples of ammonium phosphates include triammonium phosphate, diammonium hydrogen phosphate, and ammonium dihydrogen phosphate. Examples of alkali metal phosphates include trisodium phosphate, tripotassium phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, sodium dihydrogen phosphate, and potassium dihydrogen phosphate. Examples of alkaline earth metal phosphates include calcium hydrogen phosphate.

[0039] In the heat treatment step, the second phosphorus compound may be used in an amount of 0.1% by mass or more and 47% by mass or less relative to the nitride phosphor. The amount of the second phosphorus compound used may be preferably 1% by mass or more, or 5% by mass or more, and may be preferably 40% by mass or less, or 30% by mass or less.

[0040] The amount of water present in the heat treatment step may be, for example, 85% or more, preferably 90% or more, or 95% or more, in terms of the relative humidity of the atmosphere in the heat treatment step. The upper limit of the relative humidity of the atmosphere in the heat treatment step may be, for example, 100% or less. As a method for performing the heat treatment step in such an atmosphere, for example, an unsaturated type highly accelerated life testing (PCT) apparatus can be used, which can increase the air pressure in a chamber with steam and create an environment of high temperature, high humidity, and high pressure.

[0041] The heat treatment temperature in the heat treatment step may be, for example, 90°C or higher and 400°C or lower, in order to maintain the relative humidity of the atmosphere in the heat treatment step as described above. The heat treatment temperature may be preferably 100°C or higher or 150°C or higher, and preferably 350°C or lower or 300°C or lower. The heat treatment can be performed, for example, by raising the temperature from room temperature to a predetermined heat treatment temperature and maintaining the predetermined temperature. The heat treatment time, as the time for maintaining the predetermined heat treatment temperature, may be, for example, 1 hour or higher and 100 hours or lower. The heat treatment time may be preferably 5 hours or higher or 10 hours or higher, and preferably 50 hours or lower or 30 hours or lower.

[0042] The pressure in the heat treatment step may be, for example, -0.010 MPa or more and 1.5 MPa or less in terms of gauge pressure. The pressure in the heat treatment step may be preferably 0.15 MPa or more, or 0.30 MPa or more, and preferably 1.0 MPa or less, or 0.80 MPa or less.

[0043] The heat-treated product formed in the heat treatment step contains a first phosphorus compound. The content of the first phosphorus compound in the heat-treated product may be, for example, 0.07% by mass or more and 0.8% by mass or less, preferably 0.1% by mass or more or 0.3% by mass or more, and preferably 0.7% by mass or less or 0.5% by mass or less, in terms of the content of phosphorus atoms.

[0044] The heat treatment step can be carried out by, for example, heat treating a mixture containing a nitride phosphor and a second phosphorus compound in the presence of liquid or gaseous water. The heat treatment step may also include a first step of forming hydroxyl groups on the surface of the nitride phosphor by, for example, reacting the nitride phosphor with liquid or gaseous water, and a second step of forming a first phosphorus compound from the hydroxyl groups formed on the surface of the nitride phosphor and the second phosphorus compound.

[0045] In the first step, the nitride phosphor is reacted with liquid or gaseous water to form hydroxyl groups on the surface of the nitride phosphor, for example. The first step may include, for example, a partial hydrolysis reaction on the surface of the nitride phosphor. The first step can be carried out by heat-treating the nitride phosphor in the presence of water, for example. The amount of water present in the first step may be at least 3 times equivalent, preferably at least 4 times equivalent, or at least 5 times equivalent, and preferably at most 10 times equivalent, or at most 8 times equivalent, based on the mass of the phosphor. The heat treatment temperature in the first step may be, for example, from 90°C to 400°C, and preferably from 95°C to 150°C.

[0046] In the second step, the nitride phosphor obtained in the first step and the second phosphorus compound are heat-treated to form the first phosphorus compound on the surface of the nitride phosphor. The second step can be performed by heat-treating the mixture of the nitride phosphor obtained in the first step and the second phosphorus compound. The heat treatment temperature in the second step can be, for example, 90°C or higher and 400°C or lower. The heat treatment temperature in the second step can be preferably 100°C or higher or 120°C or higher, and preferably 350°C or lower or 300°C or lower. The heat treatment time in the second step can be, for example, 1 hour or higher and 100 hours or lower, and preferably 5 hours or higher and 50 hours or lower. The second step can be performed in the presence of water. The water in the second step can be liquid water or gaseous water. When the water in the second step is gaseous, the relative humidity in the atmosphere in the second step can be, for example, 85% or higher, preferably 90% or higher or 95% or higher. The upper limit of the relative humidity in the atmosphere in the second step may be, for example, 100% or less.

[0047] Method for manufacturing nitride phosphor The method for producing a nitride phosphor may include a preparation step of preparing a raw material mixture containing, for example, a lanthanum (La) source, a silicon (Si) source, and a cerium (Ce) source, at least one of which is a nitride, and a nitride phosphor preparation step of heat-treating the prepared raw material mixture to obtain a nitride phosphor.

[0048] In the preparation step, a raw material mixture for obtaining a desired nitride phosphor is prepared. The raw material mixture contains at least a lanthanum (La) source, a silicon (Si) source, and a cerium (Ce) source, and optionally contains at least one rare earth element M selected from the group consisting of rare earth elements other than La and Ce. 1 Rare earth elements M including 1 The rare earth element M other than La and Ce may further comprise a source of 1 Rare earth elements M including 1The source may contain at least one selected from the group consisting of at least yttrium (Y), gadolinium (Gd), and lutetium (Lu), may contain at least one of Y and Gd, or may contain at least Y. In addition, at least one selected from the group consisting of a lanthanum source, a silicon source, and a cerium source may also serve as a nitrogen source, and the rare earth element M 1 The source may also be a nitrogen source.

[0049] The lanthanum source may be a compound containing La, La alone, an alloy containing La, or the like, or at least one selected from the group consisting of these. The compound containing La may be at least one selected from the group consisting of oxides, halides (e.g., fluorides, chlorides, etc.), nitrides, alloys, etc., and preferably at least one selected from the group consisting of oxides, fluorides, and nitrides. The lanthanum source may be a single type or a combination of two or more types. The purity of the lanthanum source may be, for example, 95% or more, preferably 97% or more, or 98% or more. The upper limit of the purity of the lanthanum source may be, for example, 99.999% or less.

[0050] The ratio of the number of moles of element La contained in the La source contained in the raw material mixture to 6 moles of silicon (Si) contained in the raw material mixture may be, for example, 0 or more and 4.5 or less, preferably 1.2 or more, 1.5 or more, or 2.0 or more, and preferably 4.3 or less, or 4.0 or less.

[0051] The silicon source may be a compound containing Si, elemental Si, an alloy containing Si, or the like, or at least one selected from the group consisting of these. The compound containing Si may be at least one selected from the group consisting of oxides, nitrides, alloys, or the like, preferably at least one selected from the group consisting of oxides and nitrides, and more preferably at least a nitride. The compound containing Si contained in the Si source may be a single type or a combination of two or more types. The purity of the silicon source may be, for example, 95% or more, preferably 97% or more, or 98% or more. The upper limit of the purity of the silicon source may be, for example, 99.999% or less.

[0052] The cerium source may be a compound containing Ce, Ce alone, an alloy containing Ce, or the like, or at least one selected from the group consisting of these. The compound containing Ce may be at least one selected from the group consisting of oxides, halides (e.g., fluorides, chlorides, etc.), nitrides, alloys, etc., preferably at least one selected from the group consisting of oxides, fluorides, and nitrides, and more preferably at least a fluoride. The Ce-containing compound contained in the Ce source may be a single compound or a combination of two or more compounds. The purity of the cerium source may be, for example, 95% or more, preferably 97% or more, or 98% or more. The upper limit of the purity of the cerium source may be, for example, 99.999% or less.

[0053] The ratio of the number of moles of element Ce contained in the Ce source contained in the raw material mixture to 6 moles of silicon (Si) contained in the raw material mixture may be, for example, greater than 0 and not greater than 1.5, preferably not less than 0.05 or not less than 0.1, and preferably not greater than 1.3 or not greater than 1.2.

[0054] Rare earth element M 1 The source may contain at least one element selected from the group consisting of Y, Lu and Gd, and preferably contains at least Y. 1 Rare earth elements M contained in the source1 The molar content of Y relative to the total molar amount of the rare earth element M may be, for example, 90% or more, preferably 95% or more, or 98% or more. 1 The source is rare earth element M 1 Compounds containing rare earth elements M 1 element, rare earth element M 1 The compound containing the rare earth element M may be at least one selected from the group consisting of oxides, halides (e.g., fluorides, chlorides, etc.), nitrides, alloys, etc., and preferably at least one selected from the group consisting of oxides, fluorides, and nitrides. 1 Rare earth elements M contained in the source 1 The compound containing the rare earth element M may be one kind alone or two or more kinds in combination. 1 The purity of the source may be, for example, 95% or more, preferably 97% or more, or 98% or more. 1 The upper limit of source purity may be, for example, 99.999% or less.

[0055] Rare earth element M contained in the raw material mixture 1 Rare earth elements M contained in the source 1 The molar ratio of the above may be, for example, greater than 0 and less than or equal to 1.5, preferably greater than or equal to 0.2, or greater than or equal to 0.3, and preferably less than or equal to 1.4, or less than or equal to 1.2, when the silicon (Si) contained in the raw material mixture is 6 moles.

[0056] Rare earth element M contained in the raw material mixture 1 The ratio of the total number of moles of the element La and the element Ce to 6 moles of silicon (Si) contained in the raw material mixture may be, for example, greater than 0.15 and less than 3, preferably greater than 0.2 or greater than 0.3, and preferably less than 2.6 or less than 2.4. 1The ratio of the total number of moles of the elemental Ce source to 6 moles of silicon (Si) contained in the mixture may be, for example, 3 or more and 7.5 or less, preferably 3.1 or more, or 3.2 or more, and preferably 6.8 or less, 6.3 or less, or 5.8 or less.

[0057] The raw material mixture contains a lanthanum source, a silicon source, a cerium source, and a rare earth element M 1 The raw material mixture may contain a halide such as fluoride as at least a part of at least one element source selected from the group consisting of elements. The halide may function as a flux. When the raw material mixture contains a halide, the content of the halide relative to the total mass of the raw material mixture may be, for example, 1 mass% or more and 40 mass% or less, preferably 2.5 mass% or more or 5 mass% or more, and preferably 35 mass% or less or 30 mass% or less.

[0058] The raw material mixture contains a lanthanum source, a silicon source, a cerium source, and optionally a rare earth element M 1 The source and the raw material are weighed to a desired blend ratio, and then mixed by a mixing method using a ball mill or the like, a mixing method using a mixer such as a Henschel mixer or a V-type blender, a mixing method using a mortar and pestle, etc. Mixing can be performed by dry mixing, or by wet mixing with the addition of a solvent or the like.

[0059] The nitride phosphor preparation step includes heat-treating the prepared raw material mixture to obtain the nitride phosphor. The heat-treatment temperature of the raw material mixture may be, for example, 1400° C. or higher and 2000° C. or lower. The heat-treatment temperature of the raw material mixture may be preferably 1500° C. or higher, or 1600° C. or higher, and may be preferably 1900° C. or lower, or 1850° C. or lower.

[0060] The heat treatment in the nitride phosphor preparation step may include raising the temperature to a predetermined heat treatment temperature, maintaining the predetermined heat treatment temperature, and lowering the temperature from the heat treatment temperature. The rate of temperature rise from room temperature to the predetermined heat treatment temperature may be, for example, 0.02°C / min or more and 5°C / min or less, preferably 0.08°C / min or more or 0.15°C / min or more, and preferably 3.3°C / min or less or 1.7°C / min or less.

[0061] The heat treatment time for maintaining the predetermined heat treatment temperature may be, for example, 1 hour or more and 30 hours or less, preferably 2 hours or more or 4 hours or more, and preferably 20 hours or less or 10 hours or less. The rate of temperature decrease from the predetermined heat treatment temperature to room temperature may be, for example, 1°C / min or more and 600°C / min or less.

[0062] The atmosphere in which the raw material mixture is heat-treated may be an inert atmosphere containing a rare gas such as nitrogen or argon, or a reducing atmosphere containing a reducing gas such as hydrogen.

[0063] The pressure for the heat treatment of the raw material mixture can be, for example, normal pressure to 200 MPa. From the viewpoint of suppressing decomposition of the nitride phosphor produced, a higher pressure is preferable, and a gauge pressure of 0.1 MPa to 200 MPa is preferable, 0.5 MPa to 20 MPa is more preferable, and 0.6 MPa to 1.2 MPa is even more preferable because it has fewer restrictions on industrial equipment.

[0064] The heat treatment of the raw material mixture can be carried out, for example, using a gas pressure electric furnace. The heat treatment of the raw material mixture can be carried out, for example, by filling the raw material mixture into a crucible, boat, etc. made of a carbon material such as graphite or a boron nitride (BN) material. In addition to carbon materials and boron nitride materials, alumina (Al2O3), Mo, W, etc. can also be used.

[0065] After the heat treatment of the raw material mixture, a sizing step may be included in which the heat-treated product obtained by the heat treatment is subjected to a combination of processes such as crushing, pulverization, washing, and classification. The sizing step allows for the production of powder with a desired particle size. Specifically, the heat-treated product is coarsely pulverized and then pulverized to a predetermined particle size using a common pulverizer such as a ball mill, jet mill, or vibration mill. Washing can be performed, for example, by dispersing the heat-treated product in water and performing solid-liquid separation. Solid-liquid separation can be performed by industrially commonly used methods such as filtration, suction filtration, pressure filtration, centrifugation, and decantation. The heat-treated product may also be subjected to an acid treatment. The acid treatment can be performed, for example, by dispersing the heat-treated product in an acidic aqueous solution and performing solid-liquid separation. After the acid treatment, water washing and solid-liquid separation may be performed. After solid-liquid separation, a drying treatment may be performed. The drying treatment can be performed using industrially commonly used equipment such as a vacuum dryer, a hot air heating dryer, a conical dryer, or a rotary evaporator.

[0066] Wavelength conversion material The wavelength conversion member includes a support and a phosphor layer disposed on the support and containing a phosphor. The phosphor contained in the phosphor layer may include a nitride phosphor containing La, Ce, Si, and N, and a first phosphorus compound present on the surface of the nitride phosphor. The wavelength conversion member can be combined with a light-emitting element to form a light-emitting device. By including a nitride phosphor with a first phosphorus compound formed on its surface as the phosphor, the emission intensity of the output light increases in proportion to the output of the light-emitting element, and the wavelength conversion member can exhibit emission characteristics with excellent linearity, resulting in excellent emission characteristics.

[0067] 1A and 1B are schematic diagrams illustrating an example of a wavelength conversion member. FIG. 1A is a schematic plan view of a wavelength conversion member 50 viewed from the main surface side. FIG. 1B is a schematic side view of the wavelength conversion member 50 viewed from the side surface side and an enlarged view of a partial cross section thereof. As shown in FIG. 1A, the wavelength conversion layer 52 is disposed along the circumference of a disk-shaped support 54. As shown in FIG. 1B, the wavelength conversion layer 52 is disposed on one main surface of the support 54 by laminating a phosphor layer 80 containing phosphor 70 and a light transmission layer 82 containing resin 76 in this order.

[0068] Light-emitting device The light emitting device may include a light emitting element having an emission peak wavelength in the wavelength range of 350 nm to 500 nm, and a phosphor excited by the light emitting element. The phosphor included in the light emitting device may include a nitride phosphor containing La, Ce, and Si, and a first phosphorus compound present on the surface of the nitride phosphor. The phosphor may also be included in a phosphor layer constituting the wavelength conversion member.

[0069] The light-emitting element may have a peak emission wavelength in the wavelength range of, for example, 350 nm to 500 nm, preferably 380 nm to 470 nm, or 400 nm to 460 nm. By using a light-emitting element having a peak emission wavelength within this wavelength range as an excitation light source, it is possible to construct a light-emitting device that emits a mixed color of light from the light-emitting element and fluorescence from the phosphor. Furthermore, since a portion of the light emitted from the light-emitting element can be effectively utilized as part of the light emitted externally from the light-emitting device, a light-emitting device with high luminous efficiency can be obtained.

[0070] The half-width of the emission spectrum of the light-emitting element may be, for example, 30 nm or less. It is preferable to use, as the light-emitting element, a semiconductor light-emitting element using, for example, a nitride-based semiconductor. By using a semiconductor light-emitting element as the excitation light source, it is possible to obtain a light-emitting device that is highly efficient, has high linearity in output relative to input, and is stable and resistant to mechanical shock. The light-emitting element may be a light-emitting diode (LED) or a laser diode (LD). One type of light-emitting element may be used alone, or two or more types may be used in combination.

[0071] The output of the light emitting element is, for example, 0.5 W / mm as the optical power density incident on the wavelength conversion member. 2 or more, preferably 5 W / mm 2 or more than 10W / mm 2 The upper limit of the output of the light emitting element is, for example, 1000 W / mm 2 may be less than 500 W / mm2 or less, or 150W / mm 2 When the output of the light emitting element is within the above range, the wavelength conversion member has better linearity according to the output of the light emitting element.

[0072] An example of the configuration of a light-emitting device will now be described with reference to the drawings. FIG. 2 is a schematic diagram showing an example of the configuration of a light-emitting device. The light-emitting device 100 includes a light-emitting element 10, an incident optical system 20, and a wavelength conversion member 50. The wavelength conversion member 50 includes a support 54 and a wavelength conversion layer 52 disposed on the support 54. The wavelength conversion layer 52 includes a phosphor layer 80 containing phosphor 70 and a light-transmitting layer 82 containing resin 76. Light emitted from the light-emitting element 10 passes through the incident optical system 20, enters the wavelength conversion member 50 from the support 54 side, and passes through the phosphor layer 80 containing phosphor 70, where at least a portion of the incident light is wavelength-converted by the phosphor 70. Alternatively, both the wavelength-converted light and the remaining portion of the incident light that has not been wavelength-converted are emitted from the wavelength conversion member 50. In this case, the light emitted by the light-emitting device 100 is a mixture of the light from the light-emitting element 10 and the wavelength-converted light.

[0073] FIG. 3 is a schematic diagram illustrating an example of the configuration of a light-emitting device. The light-emitting device 110 includes a light-emitting element 10, an incident optical system 20, and a wavelength conversion member 50. The wavelength conversion member 50 includes a support 54 and a wavelength conversion layer 52 disposed on the support 54. The wavelength conversion layer 52 is formed by stacking a phosphor layer 80 containing phosphor 70 and a light-transmitting layer 82 containing resin 76 in this order. Light emitted from the light-emitting element 10 passes through the incident optical system 20 and enters the wavelength conversion member 50 from the wavelength conversion layer 52 side. The light passes through the wavelength conversion layer 52 and is reflected and emitted from the wavelength conversion layer 52. At least a portion of the light passing through the wavelength conversion layer 52 is wavelength-converted by the phosphor 70. Alternatively, both the wavelength-converted light and the remaining portion of the incident light that was not wavelength-converted are emitted from the wavelength conversion member 50. In this case, the light emitted from the light-emitting device 110 is a mixture of the light from the light-emitting element 10 and the wavelength-converted light.

[0074] Light source device for projector A light source device for a projector includes the light emitting device described above. By including a light emitting device that has excellent light emitting characteristics at high output, a high output projector can be configured.

[0075] The light emitting device provided with the wavelength conversion member of the present disclosure can be used not only as a light source device for a projector, but also as a light emitting device provided in a light source for general lighting devices such as ceiling lights, special lighting devices such as spotlights, stadium lighting, and studio lighting, vehicle lighting devices such as headlamps, projection devices such as head-up displays, endoscope lights, imaging devices such as digital cameras, mobile phones, and smartphones, monitors for personal computers (PCs), liquid crystal display devices such as notebook personal computers, televisions, personal digital assistants (PDX), smartphones, tablet PCs, and mobile phones, etc. [Example]

[0076] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0077] Example 1 Lanthanum nitride (LaN) was used as the La source, yttrium nitride (YN) as the Y source, silicon nitride (Si3N4) as the Si source, and cerium nitride (CeN) as the Ce source. Each raw material was weighed out so that the molar ratio of each element was La:Y:Si:Ce = 2.0:0.5:6:0.5. Specifically, 42.78 g of LaN, 7.20 g of YN, 39.25 g of Si3N4, and 10.78 g of CeN were weighed out.

[0078] The weighed raw materials were thoroughly crushed and mixed in a dry system to obtain a raw material mixture. The obtained raw material mixture was packed into a crucible and heat-treated at 1800°C for 5 hours in a reducing atmosphere. The rate of temperature increase from room temperature to 1800°C was set at 5°C / min to obtain a heat-treated product. The heat-treated product was crushed and dispersed in water, and then recovered by solid-liquid separation to obtain a phosphor. The recovered phosphor was treated with a 7% hydrochloric acid solvent and then washed with water until the pH became neutral, about 7.0. The composition of the powdered nitride phosphor obtained by drying was then La. 1.92 Y 0.46 Ce 0.45 Si6N 10.64 O 0.05 H 0.04 It was.

[0079] To the obtained nitride phosphor (20 g), 0.02 g of diammonium hydrogen phosphate (NH4)2HPO4, which is 0.1% by mass relative to the nitride phosphor, was added, and the mixture was stored in an unsaturated type highly accelerated lifetime testing apparatus (PCT apparatus) under conditions of relative humidity: 100% and temperature: 130°C for 24 hours, followed by heat treatment, washing with water, and drying overnight in a dryer at 85°C to obtain a powdered phosphor of Example 1.

[0080] Example 2 The phosphor of Example 2 was obtained in the same manner as in Example 1, except that 0.2 g (1 mass %) of diammonium hydrogen phosphate (NH4)2HPO4 was added to the obtained nitride phosphor (20 g).

[0081] Example 3 A phosphor of Example 3 was obtained in the same manner as in Example 1, except that 2.0 g (10 mass %) of diammonium hydrogen phosphate (NH4)2HPO4 was added to the obtained nitride phosphor (20 g).

[0082] Example 4 The phosphor of Example 4 was obtained in the same manner as in Example 1, except that 5.0 g (25 mass %) of diammonium hydrogen phosphate (NH4)2HPO4 was added to the obtained nitride phosphor (20 g).

[0083] Example 5 The phosphor of Example 5 was obtained in the same manner as in Example 1, except that 9.0 g (45 mass %) of diammonium hydrogen phosphate (NH4)2HPO4 was added to the obtained nitride phosphor (20 g).

[0084] Comparative Example 1 The nitride phosphor obtained in Example 1 was designated as the phosphor of Comparative Example 1. That is, the phosphor of Comparative Example 1 was not subjected to heat treatment in the presence of diammonium hydrogen phosphate and water.

[0085] Comparative Example 2 The obtained nitride phosphor was stored for 24 hours in an unsaturated highly accelerated temperature tester (PCT tester) under conditions of relative humidity: 100% and temperature: 130°C without adding diammonium hydrogen phosphate, thereby obtaining a powdered phosphor of Comparative Example 2.

[0086] Comparative Example 3 A phosphor of Comparative Example 3 was obtained in the same manner as in Example 1, except that 10.0 g (50 mass %) of diammonium hydrogen phosphate (NH4)2HPO4 was added to the obtained nitride phosphor (20 g).

[0087] Comparative Example 4 The phosphor of Comparative Example 4 was obtained by the same procedure as in Example 1, except that 2.0 g (10 mass%) of diammonium hydrogen phosphate (NH4)2HPO4 was added to the obtained nitride phosphor (20 g) and the heat treatment conditions using an unsaturated highly accelerated lifetime test apparatus (PCT apparatus) were changed to a temperature of 130°C without humidification.

[0088] evaluation 1. Phosphorus atom, oxygen atom, and hydrogen atom content The phosphorus, oxygen, and hydrogen atom contents (mass%) of the obtained phosphorus were determined by inductively coupled plasma (ICP) emission spectroscopy and an oxygen, nitrogen, and hydrogen analyzer (HORIBA; EMGA-930). The results are shown in Table 1.

[0089] 2.Center particle size The volumetric particle size distribution of the obtained phosphor was measured using a laser diffraction particle size distribution analyzer (product name: MASTER SIZER3000, manufactured by MALVERN), and the median particle size (Dm; μm) was calculated as the particle size corresponding to the cumulative 50% from the smallest diameter side. The results are shown in Table 1.

[0090] 3. Chromaticity coordinates and relative luminous intensity The chromaticity coordinates and luminous intensity of the phosphors obtained above were measured using a quantum efficiency measurement system (QE-2000, manufactured by Otsuka Electronics Co., Ltd.). The results are shown in Table 1. The luminous intensity is shown as a relative luminous intensity (ENG:%) based on the luminous intensity of the phosphor of Comparative Example 2. FIG. 4 shows the luminous spectra of the phosphors of Examples 1 and 4 and Comparative Examples 1, 2, and 3. The luminous spectra in FIG. 4 are normalized by the maximum luminous intensity of the phosphor of Comparative Example 2.

[0091] 4. Phosphor composition The composition ratio of the constituent elements of the phosphor obtained above was determined using inductively coupled plasma (ICP) emission spectroscopy and an oxygen, nitrogen, and hydrogen analyzer (HORIBA; EMGA-930), with silicon (Si) taken as 6. The results are shown in Table 2.

[0092] [Table 1]

[0093] [Table 2]

[0094] Table 1 shows that storing the phosphor under high temperature and humidity conditions improves the luminescence intensity. Furthermore, adding phosphate and carrying out the same treatment results in even higher luminescence intensity. This is thought to be due to the effect of the nitride phosphor, which has a high refractive index, being covered with an oxide, which has a low refractive index. If the amount of phosphate added is appropriate, the excess is thought to be removed in the water washing process without participating in the reaction.

[0095] Fabrication of wavelength conversion material (Phosphor Wheel: PW) A phosphor paste was prepared by mixing 100 parts by mass of silicone resin as a binder with 167 parts by mass of the phosphor of Example 1. A metal member made of aluminum was used as the support, which was plate-shaped and disk-shaped when viewed from the main surface side. A wavelength conversion layer was formed on one main surface of the support by printing the phosphor paste in a circular shape with a predetermined width along the circumference of the metal member. This resulted in a desired wavelength conversion member.

[0096] The thickness of the wavelength converting layer was measured as follows. Measurement points were set at 45° intervals around the circumference of the wavelength converting surface coated on a disk-shaped support, and measurements were taken at perpendicular points using a Digimatic Indicator (Mitutoyo). The arithmetic mean value of the thickness at each measurement point was calculated, and the thickness of the support was subtracted from the arithmetic mean value to determine the thickness of the wavelength converting layer.

[0097] Each wavelength conversion member was obtained in the same manner as above, except that the phosphor of Example 1 was replaced with the phosphors of Examples 2 to 5 and Comparative Examples 1 to 4.

[0098] Evaluation of wavelength conversion materials The emission intensity of the wavelength conversion member prepared above was measured as follows. The disk-shaped wavelength conversion member was fixed to a driving device, and the emission characteristics were measured while rotating at a rotation speed of 7200 rpm. A laser diode (LD) with an emission peak wavelength of 455 nm was prepared as an excitation light source for the wavelength conversion member, and the output density (W / mm 2) was changed, and the emission intensity of the light emitted from the wavelength conversion member at each output density was measured in the range of 470 nm or more and 800 nm or less. The emission intensity was expressed as relative Po (%) with the emission intensity for each output density of the laser diode in Comparative Example 2 as the reference (100.0%). Figure 5 shows the change in emission intensity (relative Po (%)) of the light emitted from the wavelength conversion member with respect to the change in the output density of the laser diode for the wavelength conversion members of Examples 1 and 4 and Comparative Examples 1, 2, and 3. Furthermore, for the wavelength conversion members of each Example and Comparative Example, when the output density of the laser diode (LD) was 91.5 W / mm 2 The relative Po (%) at the above values ​​is shown in Table 3.

[0099] [Table 3]

[0100] Table 3 shows that in the phosphate-added products where improvements in luminescence intensity were observed, higher luminescence intensity can also be obtained when using LD as an excitation light source. [Industrial Applicability]

[0101] The phosphor of the present disclosure can be used as a phosphor contained in a wavelength conversion member provided in a light source in, for example, general lighting devices such as ceiling lights, vehicle lighting devices such as spotlights and headlamps, projection devices such as projectors and head-up displays, imaging devices such as digital cameras, mobile phones and smartphones, monitors for personal computers (PCs), televisions, personal digital assistants (PDXs), smartphones, tablet PCs, mobile phones and other liquid crystal display devices. [Explanation of symbols]

[0102] 10: light emitting element, 50: wavelength conversion member, 52: wavelength conversion layer, 54: support, 70: phosphor, 80: phosphor layer, 82: light transmitting layer, 100, 110: light emitting device.

Claims

1. A phosphor comprising: a nitride phosphor containing La, Ce, Si, and N; and a first phosphorus compound present on a surface of the nitride phosphor; the first phosphorus compound includes at least one selected from the group consisting of lanthanum phosphate, lanthanum hydrogen phosphate, and hydrates thereof; A phosphor in which the content of phosphorus atoms contained in the phosphor is 0.07% by mass or more and 0.8% by mass or less.

2. The phosphor according to claim 1, wherein the phosphor contains oxygen atoms and hydrogen atoms, and the content of oxygen atoms contained in the phosphor is 0.6% by mass or more, and the content of hydrogen atoms contained in the phosphor is 0.02% by mass or more.

3. The phosphor according to claim 1 or 2, wherein the nitride phosphor has a composition represented by the following formula (1): L ｐ Yes ｓ M １ ｑ M ２ ｒ N ｔ (1) (In formula (1), M １ represents at least one element selected from the group consisting of rare earth elements other than La and Ce, and includes at least one element selected from the group consisting of Y, Gd, and Lu; M ２ represents at least one selected from the group consisting of Si, Ge, B, Al, and Ga, and contains at least Si, and p, q, r, s, and t satisfy the following conditions: 2.7≦p+q+s≦3.3, 0≦q≦1.2, 5.4≦r≦6.6, 10≦t≦12, 0<s≦1.

2.

4. In the formula (1), M １ The phosphor according to claim 3 , wherein the element comprises at least one of Y and Gd.

5. a light-emitting element having an emission peak wavelength in a wavelength range of 350 nm or more and 500 nm or less; A light emitting device comprising: a wavelength conversion member containing the phosphor according to claim 1 that is excited by the light emitting element.

6. The method includes heat-treating a nitride phosphor having a composition represented by the following formula (1) at a temperature of 90° C. or higher and 400° C. or lower in the presence of a second phosphorus compound in an amount of 0.1% by mass or higher and 47% by mass or lower relative to the nitride phosphor and liquid or gaseous water, The method for producing a phosphor, wherein the second phosphorus compound contains at least one selected from the group consisting of phosphoric acid, phosphorus oxide, ammonium phosphate, alkali metal phosphate, and alkaline earth metal phosphate. L ｐ Yes ｓ M １ ｑ M ２ ｒ N ｔ (1) (In formula (1), M １ represents at least one element selected from the group consisting of rare earth elements other than La and Ce, and includes at least one element selected from the group consisting of Y, Gd, and Lu; M ２ represents at least one selected from the group consisting of Si, Ge, B, Al, and Ga, and contains at least Si, and p, q, r, s, and t satisfy the following conditions: 2.7≦p+q+s≦3.3, 0≦q≦1.2, 5.4≦r≦6.6, 10≦t≦12, 0<s≦1.

2.

7. The method for producing a phosphor according to claim 6, wherein the heat treatment is carried out under conditions of a relative humidity of 85% or more.

8. 8. The method for producing a phosphor according to claim 6 or 7, wherein the heat treatment forms at least one compound selected from the group consisting of lanthanum phosphate, lanthanum hydrogen phosphate, and hydrates thereof on the surface of the nitride phosphor from the second phosphorus compound and liquid or gaseous water.

9. The method for producing a phosphor according to claim 6, wherein in the formula (1), M 1 contains at least one of Y and Gd.

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