Method for producing fluoride phosphor particles

Abstract

The present invention provides a method for producing fluoride phosphor particles that can reduce the span value of the resulting fluoride phosphor particles. [Solution] A method for producing fluoride phosphor particles, comprising the steps of: (A) preparing solution A by mixing an aqueous solution of hydrogen fluoride with a K-containing raw material; (B) mixing solution A, a Mn-containing raw material, and a first Si-containing raw material to obtain solution B containing a seed crystal; and (C) mixing the solution containing the seed crystal, the Mn-containing raw material, and a second Si-containing raw material to obtain solution C.

Description

Technical Field

[0001] The present invention relates to a method for producing fluoride phosphor particles.

Background Art

[0002] Fluoride phosphor particles are used, for example, as wavelength conversion members in light emitting diodes and the like. As a technology related to fluoride phosphor particles, for example, the technology described in Patent Document 1 can be cited.

[0003] Patent Document 1 describes a method for producing a fluoride phosphor represented by the general formula: A2SiF6:Mn (element A is an alkali metal element containing at least potassium), the method including a step of preparing an aqueous solution in which element A and fluorine are dissolved in a solvent, and a step of adding a manganese compound that supplies solid silicon dioxide and manganese other than +7 valent to the aqueous solution, the addition amount of the manganese compound being in a range such that the Mn content in the fluoride phosphor is 0.1% by mass or more and 1.5% by mass or less, and the fluoride phosphor precipitating in parallel with the dissolution of silicon dioxide in the aqueous solution. According to the method for producing a fluoride phosphor of Patent Document 1, it is described that a fluoride phosphor having high fluorescence intensity and excellent reliability can be produced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention provides a method for producing fluoride phosphor particles capable of reducing the span value of the obtained fluoride phosphor particles.

Means for Solving the Problems

[0006] According to the present invention, the following fluoride phosphor particles are provided.

[0007] [1] Step (A) involves preparing solution A by mixing an aqueous solution of hydrogen fluoride with a K-containing raw material, Step (B) involves mixing the aforementioned liquid A, a Mn-containing raw material, and a first Si-containing raw material to obtain liquid B containing a seed crystal. A method for producing fluoride phosphor particles, comprising the step (C) of mixing a liquid containing the seed crystal, the Mn-containing raw material, and a second Si-containing raw material to obtain liquid C. [2] The volume-based median diameter (D) of the first Si-containing raw material 50 ) is the volume-based median diameter (D) of the second Si-containing raw material. 50 A method for producing fluoride phosphor particles as described in [1] above, which are smaller than ). [3] The volume-based median diameter (D) of the first Si-containing raw material 50 A method for producing fluoride phosphor particles according to [1] or [2], wherein the diameter of the particle is 1 μm or more and 20 μm or less. [4] The volume-based median diameter (D) of the second Si-containing raw material 50 A method for producing fluoride phosphor particles according to any one of the above [1] to [3], wherein the diameter is 20 μm or larger. [5] A method for producing fluoride phosphor particles according to any one of [1] to [4], wherein the mass ratio (second / first) of the amount of the second Si-containing raw material mixed to the amount of the first Si-containing raw material mixed is 0.8 or more and 10.0 or less. [6] A method for producing fluoride phosphor particles according to any one of [1] to [5], wherein the Mn-containing raw material contains K2MnF6. [7] A method for producing fluoride phosphor particles according to any one of [1] to [6], wherein the K-containing raw material includes KHF2. [8] A method for producing fluoride phosphor particles according to any one of [1] to [7], wherein the first Si-containing raw material contains SiO2. [9] A method for producing fluoride phosphor particles according to any one of [1] to [8], wherein the second Si-containing raw material contains SiO2.

[10] Step (C) is a step (C1) in which the Mn-containing raw material and the second Si-containing raw material are added to the liquid containing the seed crystal and stirred to obtain liquid C1, A method for producing fluoride phosphor particles according to any one of [1] to [9], comprising the step (C2) of adding the Mn-containing raw material to the C1 liquid and stirring to obtain the C2 liquid.

[11] The above step (B) is a step (B1) in which the Mn-containing raw material is added to the liquid A and stirred to obtain liquid B1, A method for producing fluoride phosphor particles according to any one of [1] to

[10] , comprising the step (B2) of adding the first Si-containing raw material to the B1 liquid and stirring to obtain the B2 liquid.

[12] A method for producing fluoride phosphor particles according to any one of [1] to

[11] , further comprising the step (D) of mixing the aforementioned liquid C with the second Si-containing raw material to obtain liquid D.

[13] The aforementioned step (D) is a step (D1) in which the second Si-containing raw material is added to the liquid C and stirred to obtain liquid D1, A method for producing fluoride phosphor particles according to

[12] , comprising the step (D2) of adding the second Si-containing raw material to the D1 liquid and stirring to obtain the D2 liquid.

[14] A method for producing fluoride phosphor particles according to any one of [1] to

[13] above, wherein the composition of the fluoride phosphor particles is represented by the following general formula (1). General formula (1): A2M (1-n) F6:Mn 4+ n (In the general formula (1), element A is one or more alkali metal elements containing K, element M is a single element of Si, a single element of Ge, or a combination of one or more elements selected from the group consisting of Si and Ge, Sn, Ti, Zr, and Hf, and 0 < n ≤ 0.1)

[15] D of the fluoride phosphor particles obtained by the following method 50 , D 10 and D 90 The span value (D 90 -D 10 ) / D 50 of the fluoride phosphor particles calculated from is 0.80 or less, and the method for producing fluoride phosphor particles according to any one of [1] to

[14] . [Method] Weigh 30 mL of ethanol into a 50 mL beaker, add 0.03 g of fluoride phosphor particles, and perform dispersion treatment for 3 minutes using an ultrasonic homogenizer to prepare a measurement sample. Then, use a laser diffraction scattering type particle size distribution measuring device to obtain a volume-based particle size distribution curve. From the particle size distribution curve, D 10 (cumulative 10% value), D 50 (cumulative 50% value) and D 90 (cumulative 90% value) are obtained, and from the obtained D 10 , D 50 and D 90 The span value (D 90 -D 10 ) / D 50 is calculated. [Advantages of the Invention]

[0008] According to the present invention, it is possible to provide a method for producing fluoride phosphor particles capable of reducing the span value of the obtained fluoride phosphor particles. [Embodiments for Carrying Out the Invention]

[0009] Embodiments of the present invention will be described below. Unless otherwise specified, the numerical range "A to B" represents A or greater and B or less. In this specification, when simply referred to as "Si-containing raw material," it means a concept that includes both the first Si-containing raw material and the second Si-containing raw material.

[0010] Light-emitting devices are known to include composites containing fluoride phosphor particles. Such light-emitting devices are required to have low chromaticity variation. However, our inventors' research has shown that there is room for improvement in the variation of chromaticity in conventional light-emitting devices containing composites with fluoride phosphor particles.

[0011] Composites containing fluoride phosphor particles are known, for example, composites in which fluoride phosphor particles are dispersed in a curable resin material. Our investigations have shown that in such composites, large variations in the sedimentation of fluoride phosphor particles in the curable resin material during the composite manufacturing process lead to large variations in the chromaticity of the light-emitting device. Further investigations by our inventors revealed that increasing the span value of the fluoride phosphor particles increases the sedimentation variation of the fluoride phosphor particles in the curable resin material.

[0012] The present invention has been made in view of the above circumstances, and provides a method for producing fluoride phosphor particles that can reduce the span value of the obtained fluoride phosphor particles.

[0013] Furthermore, a light-emitting device containing fluoride phosphor particles obtained by the method for producing fluoride phosphor particles according to this embodiment can reduce variations in the chromaticity of the light-emitting device.

[0014] [Method for producing fluoride phosphor particles] The method for manufacturing fluoride phosphor particles of the present embodiment includes a step (A) of preparing a solution A by mixing an aqueous solution of hydrogen fluoride and a K-containing raw material, a step (B) of mixing solution A, a Mn-containing raw material, and a first Si-containing raw material to obtain a solution B containing seed crystals, and a step (C) of mixing the solution containing seed crystals, a Mn-containing raw material, and a second Si-containing raw material to obtain a solution C.

[0015] In the method for manufacturing fluoride phosphor particles of the present embodiment, by using the first Si-containing raw material in step (B), seed crystals with a small span value are obtained, and then by using the second Si-containing raw material in step (C), the span value of the fluoride phosphor particles obtained can be reduced while maintaining the span value and gradually growing the seed crystals.

[0016] First, each raw material in the method for manufacturing fluoride phosphor particles of the present embodiment will be described.

[0017] <Aqueous solution of hydrogen fluoride> The concentration of the aqueous solution of hydrogen fluoride in the present embodiment is not particularly limited, but is preferably 40% by mass or more and 80% by mass or less, more preferably 45% by mass or more and 70% by mass or less, and still more preferably 50% by mass or more and 60% by mass or less. The concentration of the aqueous solution of hydrogen fluoride in the present embodiment may be a saturated concentration. By adjusting the numerical range of the concentration of the aqueous solution of hydrogen fluoride, the particle diameter of the obtained fluoride phosphor particles can be adjusted to a desired value.

[0018] <K-containing raw material> The K-containing raw material in the present embodiment is not particularly limited, and any compound that can supply potassium atoms may be used. The K-containing raw material in the present embodiment includes, for example, at least one selected from the group consisting of water-soluble potassium salts such as KHF2, KF, KOH, KCl, KBr, KI, potassium acetate, and K2CO3, and preferably contains KHF2.

[0019] <Mn-containing raw material> The Mn-containing raw material in the present embodiment is not particularly limited, and any compound that can supply manganese atoms may be used. The Mn-containing raw material of this embodiment includes, for example, at least one from the group consisting of fluorides, oxides, chlorides, sulfates, and nitrates. The Mn-containing raw material of this embodiment preferably contains fluoride, and more preferably contains hexafluoromanganate, from the viewpoint of efficiently substituting Mn for Si sites in the fluoride phosphor and further improving the luminescence characteristics of the fluoride phosphor.

[0020] Examples of hexafluoromanganates include at least one selected from the group consisting of Na2MnF6, K2MnF6, Rb2MnF6, MgMnF6, CaMnF6, SrMnF6, and BaMnF6. The Mn-containing raw material of this embodiment preferably contains K2MnF6, from the viewpoint of being able to simultaneously supply fluorine atoms and potassium atoms that constitute fluoride phosphor particles in addition to manganese atoms.

[0021] In this embodiment, the total amount of Mn atoms in the Mn-containing raw material is preferably 0.01 moles or more and 0.10 moles or less, and more preferably 0.03 moles or more and 0.09 moles or less, when the amount of Si atoms in the Si-containing raw material is considered to be 1 mole. The total amount of each atom mentioned above refers to the total amount of each atom in the entire manufacturing process of fluoride phosphor particles.

[0022] <First Si-containing raw material> The first Si-containing raw material in this embodiment is not particularly limited and can be any compound that can supply silicon atoms. The first Si-containing raw material of this embodiment includes at least one selected from the group consisting of SiO2, K2SiF6, and H2SiF6, and preferably includes SiO2 from the viewpoint of improving the luminescence properties of the fluoride phosphor particles and ease of obtaining the raw material.

[0023] The median diameter (D) of the first Si-containing raw material of this embodiment, based on volume. 50 The particle size is preferably 1 μm to 20 μm, more preferably 2 μm to 15 μm, and even more preferably 3 μm to 10 μm. D of the first Si-containing raw material 50 If the value is above the lower limit mentioned above, it further promotes the growth of the seed crystal, and the D of the fluoride phosphor obtained 50 This can be made larger, and the D of the first Si-containing raw material 50 If the above upper limit is below, the span value of the seed crystal can be made smaller, and the span value of the resulting fluoride phosphor can be made smaller. That is, the D of the first Si-containing raw material 50 If it is within the above range, the D of the fluoride phosphor obtained 50 It is possible to increase the value while keeping the span value small.

[0024] <Second Si-containing raw material> The second Si-containing raw material of this embodiment differs from the first Si-containing raw material in terms of its median diameter (D) by volume. 50 ) refers to raw materials containing different types of Si. The compound constituting the second Si-containing raw material in this embodiment may be the same as or different from the compound constituting the first Si-containing raw material.

[0025] The second Si-containing raw material of this embodiment includes at least one selected from the group consisting of SiO2, K2SiF6, and H2SiF6, and preferably includes SiO2 from the viewpoint of improving the luminescence properties of the fluoride phosphor particles and ease of obtaining the raw material.

[0026] The volume-based median diameter (D) of the second Si-containing raw material in this embodiment 50 The median diameter (D) of the second Si-containing raw material of this embodiment is preferably 20 μm or more, more preferably 30 μm or more, even more preferably 35 μm or more, and even more preferably 40 μm or more, and the upper limit is not particularly limited, but may be, for example, 300 μm or less, 200 μm or less, 100 μm or less, or 70 μm or less. 50 The particle size is preferably 20 μm to 300 μm, more preferably 30 μm to 200 μm, even more preferably 35 μm to 100 μm, and even more preferably 40 μm to 70 μm. The second Si-containing raw material is D 50 If the value is above the lower limit mentioned above, the seed crystal can be gradually grown while maintaining the span value, and the span value of the resulting fluoride phosphor particles can be made smaller.

[0027] The median diameter (D) of the first Si-containing raw material of this embodiment, based on volume. 50 ) preferably has a volume-based median diameter (D) of the second Si-containing raw material. 50 It is smaller than ). In step (B), a seed crystal with a small span value is obtained by using a first Si-containing raw material with a small particle size. Then, in step (C), the seed crystal is gradually grown while maintaining the span value by using a second Si-containing raw material with a large particle size. This makes it possible to reduce the span value of the resulting fluoride phosphor particles, and also reduces the D of the resulting fluoride phosphor particles. 50 It can be adjusted to the desired value.

[0028] Volume-based median diameter (D) of the second Si-containing raw material 50 ) and the volume-based median diameter (D) of the first Si-containing raw material 50 The difference between the two is preferably 15 μm or more and 150 μm or less, more preferably 20 μm or more and 100 μm or less, and even more preferably 30 μm or more and 70 μm or less.

[0029] The mass ratio (2nd / 1st) of the amount of the second Si-containing raw material to the amount of the first Si-containing raw material is preferably 0.8 to 10.0, more preferably 1.0 to 8.0, even more preferably 1.2 to 6.0, and even more preferably 1.3 to 5.0. By setting the above mass ratio (2nd / 1st) to above the above lower limit, the D of the obtained fluoride phosphor particles 50 This can be made larger. On the other hand, by making the above mass ratio (2nd / 1st) less than or equal to the above upper limit, the D of the obtained fluoride phosphor particles can be increased. 50 This can be made smaller. In other words, by adjusting the above mass ratio (2nd / 1st), the D of the fluoride phosphor particles can be reduced. 50 It can be adjusted to the desired value. The amounts of the first Si-containing raw material and the second Si-containing raw material refer to the total amount of Si-containing raw materials mixed in the entire manufacturing process of fluoride phosphor particles, respectively.

[0030] The median diameter (D) of the Si-containing raw material in this embodiment is based on volume. 50 ) refers to the value obtained by the measurement method described below.

[0031] [Median diameter (D) of Si-containing raw material by volume] 50 ) Measurement method] Measure 100 mL of filtered water containing 0.001% by mass of sodium hexametaphosphate into a 200 mL beaker, add 0.03 g of Si-containing raw material, and disperse it using an ultrasonic homogenizer for 3-4 minutes to prepare the measurement sample. Then, obtain a volume-based particle size distribution curve using a laser diffraction scattering particle size distribution analyzer. From the obtained particle size distribution curve, determine the D of the Si-containing raw material. 50 (Calculate the cumulative 50th percentile value) and determine the median diameter (D) based on volume. 50 )

[0032] The following describes in detail each step of the method for producing fluoride phosphor particles according to this embodiment.

[0033] <Process (A)> The method for producing fluoride phosphor particles according to this embodiment includes step (A) of preparing solution A, which is a mixture of an aqueous solution of hydrogen fluoride and a K-containing raw material.

[0034] In step (A), the amount of K atoms mixed in the K-containing raw material is, for example, 0.03 moles or more and 0.08 moles or less, preferably 0.04 moles or more and 0.07 moles or less, when the amount of hydrogen fluoride in the aqueous solution of hydrogen fluoride is considered to be 1 mole. If the above mixing amount is below the above upper limit, the D of the obtained fluoride phosphor particles 50 It can be made larger.

[0035] In step (A), the method for preparing solution A is not particularly limited, but one example is to prepare solution A by adding the K-containing raw material to a beaker containing an aqueous solution of hydrogen fluoride and stirring with a magnetic stirrer. The temperature during stirring is, for example, room temperature.

[0036] <Process (B)> The method for producing fluoride phosphor particles according to this embodiment includes step (B) of mixing solution A, a Mn-containing raw material, and a first Si-containing raw material to obtain solution B containing a seed crystal.

[0037] Step (B) may be a method of obtaining liquid B by simultaneously adding the Mn-containing raw material and the first Si-containing raw material to liquid A and stirring, or it may be a method of obtaining liquid B by sequentially adding the Mn-containing raw material and the first Si-containing raw material to liquid A and stirring.

[0038] In this specification, "simultaneous input of raw materials" includes cases where the first raw material is added, and then the next raw material is added immediately afterward.

[0039] Step (B) preferably includes the steps of (B1) of adding a Mn-containing raw material to liquid A and stirring to obtain liquid B1, and (B2) of adding a first Si-containing raw material to liquid B1 and stirring to obtain liquid B2.

[0040] The interval between the time the raw material is added in process (B1) and the time the raw material is added in process (B2) may be, for example, 30 seconds or more and 150 seconds or less, and preferably 60 seconds or more and 120 seconds or less.

[0041] In process (B), solution B refers to the solution obtained at the end of process (B). If process (B) consists of process (B1) and process (B2), then the liquid B2 obtained in process (B2) becomes liquid B. Furthermore, if step (B) includes, in addition to steps (B1) and (B2), a step (B3) in which, for example, Mn-containing raw material and / or a first Si-containing raw material are added to liquid B2 and stirred to obtain liquid B3, then liquid B3 becomes liquid B.

[0042] Furthermore, solution B contains seed crystals. Seed crystals refer to crystals that precipitate as the first Si-containing raw material dissolves.

[0043] In step (B), it is preferable to cool the solution to room temperature (25°C) or below, for example, to a range of -10°C to 10°C. A higher solution temperature allows the first Si-containing raw material to dissolve more quickly, resulting in a smaller span value for the resulting fluoride phosphor particles. On the other hand, if the solution temperature is high, the heat of dissolution increases, which may cause the resulting fluoride phosphor particles to deteriorate easily, and may also expose workers to danger. Therefore, it is preferable to keep the solution temperature within the above range. Furthermore, it is preferable to add each ingredient while continuously stirring the solution.

[0044] <Process (C)> The method for producing fluoride phosphor particles according to this embodiment includes a step (C) of mixing a liquid containing a seed crystal, a Mn-containing raw material, and a second Si-containing raw material to obtain liquid C.

[0045] The liquid containing the seed crystal is not particularly limited as long as it contains the seed crystal obtained by step (B). The liquid containing the seed crystal can be, for example, liquid B obtained by step (B). Another embodiment of the liquid containing the seed crystal is, for example, a liquid obtained by removing the liquid portion of liquid B to recover the seed crystal, and then mixing the recovered seed crystal with an aqueous solution of hydrogen fluoride, a K-containing raw material, and a Mn-containing raw material.

[0046] Step (C) may be a method of obtaining solution C by simultaneously adding a Mn-containing raw material and a second Si-containing raw material to a liquid containing a seed crystal and stirring, or it may be a method of obtaining solution C by sequentially adding a Mn-containing raw material and a second Si-containing raw material to a liquid containing a seed crystal and stirring.

[0047] Step (C) preferably includes steps (C1) of adding a Mn-containing raw material and a second Si-containing raw material to a liquid containing a seed crystal and stirring to obtain liquid C1, and steps (C2) of adding a Mn-containing raw material to liquid C1 and stirring to obtain liquid C2.

[0048] Step (C) preferably further includes, in addition to steps (C1) and (C2), step (C3) of adding a Mn-containing raw material and a second Si-containing raw material to liquid C2 and stirring to obtain liquid C3. Step (C), in addition to steps (C1) to (C3), may further include step (C4), in which a Mn-containing raw material is added to liquid C3 and stirred to obtain liquid C4, and step (C5), in which a Mn-containing raw material and a second Si-containing raw material are added to liquid C4 and stirred to obtain liquid C5.

[0049] The interval between the time of the last raw material input in process (B) and the time of the first raw material input in process (C) is, for example, 10 seconds or more, preferably 20 seconds or more, and the upper limit is not particularly limited, but may be, for example, 120 seconds or less, or 100 seconds or less.

[0050] The interval between the time the raw material is added in process (C1) and the time the raw material is added in process (C2) may be, for example, 30 seconds or more and 120 seconds or less, and preferably 40 seconds or more and 90 seconds or less. If process (C) includes processes (C1) and (C2), as well as processes (C3) and later, the interval between the input times of raw materials in each process can be within the same range as the interval between the input time of raw materials in process (C1) and the input time of raw materials in process (C2).

[0051] The mass ratio of the amount of Mn-containing raw material mixed in step (C) to the amount of Mn-containing raw material mixed in step (B) may be, for example, 0.3 or more and 2.5 or less, and preferably 0.6 or more and 2.1 or less.

[0052] In process (C), solution C refers to the solution obtained at the end of process (C). For example, if process (C) consists of process (C1) and process (C2), then solution C2 obtained in process (C2) is solution C. Also, if process (C) consists of processes (C1) through (C3), then solution C3 obtained in process (C3) is solution C.

[0053] In step (C), when the second Si-containing raw material dissolves, the temperature of the solution rises due to the heat of dissolution, so it is preferable to cool the solution. Specifically, it is preferable to cool the solution so that its temperature is below room temperature (25°C). It is also preferable to add each raw material while continuously stirring the solution.

[0054] <Process (D)> The method for producing fluoride phosphor particles according to this embodiment preferably further includes the step (D) of mixing liquid C and a second Si-containing raw material to obtain liquid D. Here, step (D) can be a step in which the Mn-containing raw material is not added to the solution, but the second Si-containing raw material is added.

[0055] Step (D) may be a method in which the second Si-containing raw material is added to liquid C only once and stirred to obtain liquid D, or it may be a method in which the second Si-containing raw material is added in multiple portions and stirred to obtain liquid D.

[0056] Step (D) preferably includes the steps of (D1) of adding a second Si-containing raw material to liquid C and stirring to obtain liquid D1, and the steps of (D2) of adding a second Si-containing raw material to liquid D1 and stirring to obtain liquid D2. Step (D) may further include, in addition to steps (D1) and (D2), step (D3) of adding a second Si-containing raw material to liquid D2 and stirring to obtain liquid D3.

[0057] The interval between the time of the last raw material input in process (C) and the time of the first raw material input in process (D) may be, for example, 60 seconds or more and 180 seconds or less, and preferably 90 seconds or more and 150 seconds or less.

[0058] The interval between the time the raw material is introduced in process (D1) and the time the raw material is introduced in process (D2) may be, for example, 60 seconds or more and 180 seconds or less, and preferably 90 seconds or more and 150 seconds or less. If process (D) includes processes (D1) and (D2), as well as processes (D3) and beyond, the interval between the input times of raw materials in each process can be within the same range as the interval between the input time of raw materials in process (D1) and the input time of raw materials in process (D2).

[0059] The stirring time from the time the last raw material is added in step (D) until the stirring of the solution is completed is, for example, 8 minutes or more and 20 minutes or less, preferably 10 minutes or more and 16 minutes or less. If the stirring time is above the lower limit, the raw material can be dissolved more sufficiently, and if the stirring time is below the upper limit, aggregation and / or deterioration of the resulting fluoride phosphor particles can be further suppressed.

[0060] In process (D), solution D refers to the solution obtained at the end of process (D). For example, if process (D) consists of process (D1) and process (D2), then solution D2 obtained in process (D2) is solution D. Also, if process (D) consists of processes (D1) through (D3), then solution D3 obtained in process (D3) is solution D.

[0061] In step (D), when the second Si-containing raw material dissolves, the temperature of the solution rises due to the heat of dissolution, so it is preferable to cool the solution. Specifically, it is preferable to cool the solution so that its temperature is below room temperature (25°C). It is also preferable to add each raw material while continuously stirring the solution.

[0062] <Other processes> The method for producing fluoride phosphor particles according to this embodiment may include other steps as appropriate. Examples of other steps include a washing step and a classification step.

[0063] The washing process involves, for example, performing solid-liquid separation on the liquid after synthesis (e.g., liquid D) by decantation, filtration, etc., recovering the solid fluoride phosphor particles, and washing the fluoride phosphor particles with an organic solvent or the like. The organic solvent for washing the fluoride phosphor particles includes, for example, at least one selected from the group consisting of methanol, ethanol, and acetone. Furthermore, from the viewpoint of removing impurities more effectively, the cleaning process preferably involves washing the fluoride phosphor particles with hydrofluoric acid before washing them with an organic solvent or the like.

[0064] The classification process is, for example, a process of sieving the fluoride phosphor particles after the washing process.

[0065] [Fluoride phosphor particles] A preferred embodiment of the fluoride phosphor particles obtained by the method for producing fluoride phosphor particles according to this embodiment will be described.

[0066] The composition of the fluoride phosphor particles in this embodiment is preferably represented by general formula (1). General formula (1): A2M (1-n) F6:Mn 4+ n

[0067] In general formula (1), element A is one or more alkali metal elements containing K, and element M is elemental Si, elemental Ge, or a combination of Si and one or more elements selected from the group consisting of Ge, Sn, Ti, Zr, and Hf, 0 <n≦0.1である。

[0068] In general formula (1), element A is one or more alkali metal elements containing K. Element A is, for example, a combination of K and at least one alkali metal element selected from the group consisting of Li, Na, Rb, and Cs. The content ratio of potassium (K) in element A is preferably 50 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and even more preferably element A is a simple substance of K, from the viewpoint of further improving chemical stability.

[0069] In general formula (1), element M is a simple substance of Si, a simple substance of Ge, or a combination of one or more elements selected from the group consisting of Si and Ge, Sn, Ti, Zr, and Hf. The content ratio of silicon (Si) in element M is preferably 50 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and even more preferably element M is a simple substance of Si, from the viewpoint of further improving chemical stability.

[0070] In general formula (1), 0 < n ≤ 0.1, and preferably 0.015 ≤ n ≤ 0.04 from the viewpoint of further improving light emission characteristics.

[0071] D of the fluoride phosphor particles of the present embodiment 50 is preferably 15.0 μm or more and 35.0 μm or less, more preferably 17.0 μm or more and 33.0 μm or less, still more preferably 18.0 μm or more and 30.0 μm or less.

[0072] D of the fluoride phosphor particles of the present embodiment 10 is preferably 8.0 μm or more and 30.0 μm or less, more preferably 10.0 μm or more and 25.0 μm or less, still more preferably 12.0 μm or more and 23.0 μm or less.

[0073] D of the fluoride phosphor particles of the present embodiment 90 is preferably 20.0 μm or more and 55.0 μm or less, more preferably 25.0 μm or more and 50.0 μm or less, still more preferably 27.0 μm or more and 45.0 μm or less.

[0074] The fluoride phosphor particles of the present embodiment are D of the fluoride phosphor particles 50 , D 10 and D 90The span value (D) of the fluoride phosphor particles is calculated from this. 90 -D 10 ) / D 50 However, it is preferably 0.80 or less, more preferably 0.78 or less, and even more preferably 0.76 or less.

[0075] D of the fluoride phosphor particles of this embodiment 10 , D 50 , D 90 and span value (D 90 -D 10 ) / D 50 These terms represent the values ​​obtained by the following methods.

[0076] [method] Measure 30 mL of ethanol into a 50 mL beaker, add 0.03 g of fluoride phosphor particles, and disperse using an ultrasonic homogenizer for 3 minutes to prepare the measurement sample. Then, obtain a volume-based particle size distribution curve using a laser diffraction scattering particle size distribution analyzer. From the obtained particle size distribution curve, D 10 (Cumulative 10% value), D 50 (Cumulative 50th percentile) and D 90 (Calculate the cumulative 90th percentile) and obtain the D 10 , D 50 and D 90 Therefore, the span value (D 90 -D 10 ) / D 50 Calculate.

[0077] The Mn content of the fluoride phosphor particles in this embodiment, based on IPC emission spectroscopy analysis, is preferably 0.5% by mass or more and 1.5% by mass or less, more preferably 0.6% by mass or more and 1.3% by mass or less, and even more preferably 0.7% by mass or more and 1.1% by mass or less.

[0078] The absorption rate of the fluoride phosphor particles in this embodiment for light with a wavelength of 455 nm is preferably 70.0% or more, more preferably 75.0% or more, and the upper limit is not particularly limited, but may be, for example, 90.0% or less, or 85.0% or less.

[0079] The internal quantum efficiency of the fluoride phosphor particles in this embodiment with respect to light at a wavelength of 455 nm is preferably 75.0% or higher, more preferably 80.0% or higher, and the upper limit is not particularly limited, but may be, for example, 95.0% or lower, or 90.0% or lower.

[0080] The external quantum efficiency of the fluoride phosphor particles in this embodiment with respect to light at a wavelength of 455 nm is preferably 60.0% or more, more preferably 63.0% or more, and the upper limit is not particularly limited, but may be, for example, 80.0% or less, or 75.0% or less.

[0081] The absorption rate, internal quantum efficiency, and external quantum efficiency of the fluoride phosphor particles in this embodiment for light with a wavelength of 455 nm refer to the values ​​obtained by the method described in the example, respectively.

[0082] The applications of the fluoride phosphor particles of this embodiment are not particularly limited, but they can be used, for example, in light-emitting devices.

[0083] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted. Furthermore, the present invention is not limited to the embodiments described above, and any modifications, improvements, etc., that can achieve the objectives of the present invention are included in the present invention. [Examples]

[0084] The embodiment will be described in detail below based on examples and comparative examples. However, this embodiment is not limited in any way to the descriptions of these examples.

[0085] [Raw materials] The raw materials used in the examples and comparative examples will be described below.

[0086] The abbreviations for the raw materials in the examples and comparative examples indicate that the following materials were used. HF: Hydrogen fluoride aqueous solution with a concentration of 55% by mass, manufactured by Nitto Chemical Industry Co., Ltd. KMF: K2MnF6, manufactured by Stella Chemifa Corporation KHF2: manufactured by Fujifilm Wako Pure Chemical Corporation 5D: SiO2, FB-5D (manufactured by Denka Co., Ltd.), D 50 : 7.7 μm 3Y: SiO2, FB-3Y (manufactured by Denka Co., Ltd.), D 50 : 3.2 μm 50R: SiO2, FB-50R (manufactured by Denka Co., Ltd.), D 50 : 55.1 μm 40R: SiO2, FB-40R (manufactured by Denka Co., Ltd.), D 50 : 42.6 μm

[0087] <Median diameter (D 50 ) of SiO2 by volume standard> Weighed 100 mL of filtered water containing 0.001% by mass of sodium hexametaphosphate into a 200 mL beaker, added 0.03 g of SiO2 thereto, and performed dispersion treatment for 3 to 4 minutes using an ultrasonic homogenizer (manufactured by Nippon Seiki Co., Ltd., product name: Ultrasonic Homogenizer US-150E, settings: Altitude: 100%, Amplitude: 100%, Oscillation frequency: 19.5 kHz, Chip size: φ20, Amplitude: 32 ± 2 μm) to prepare a measurement sample. Then, using a laser diffraction scattering type particle size distribution measuring device (manufactured by Microtrac Bell Corporation, product: Microtrac MT3300EX II), a particle size distribution curve by volume standard was obtained. From the obtained particle size distribution curve, D 50 (cumulative 50% value) of SiO2 was determined and taken as the median diameter (D 50 ) by volume standard.

[0088] [Example 1] [Step (A)] At room temperature, 2100 mL of HF was added to a beaker made of fluororesin. Then, the beaker was immersed in the antifreeze in a cooling bath containing antifreeze and cooled, 260 g of KHF2 was added, and it was sufficiently stirred using a magnetic stirrer. Thus, a uniform solution (Solution A) was obtained.

[0089] <Process (B)> (Process (B1)) When solution A reached 0°C, 7.0 g of KMF was added to solution A to obtain solution B1. This addition was defined as time t=0. Furthermore, stirring and cooling of the solution were continued until the end of stirring in step (D). (Process (B2)) At t=90s, 30g of 5D was added to solution B1 to obtain solution B2.

[0090] <Process (C)> (Process (C1)) At t=120s, 3.0g of KMF and 14g of 50R were added to solution B2 to obtain solution C1. (Process (C2)) At t=180s, 3.0g of KMF was added to solution C1 to obtain solution C2. (Process (C3)) At t=240s, 3.0g of KMF and 14g of 50R were added to solution C2 to obtain solution C3. (Process (C4)) At t=300s, 2.0g of KMF was added to solution C3 to obtain solution C4. (Process (C5)) At t=360s, 2.0g of KMF and 14g of 50R were added to solution C4 to obtain solution C5.

[0091] <Process (D)> (Process (D1)) At t=480s, 14g of 50R was added to solution C5 to obtain solution D1. (Process (D2)) At t=600s, 14g of 50R was added to solution D1 to obtain solution D2. The D2 solution was continuously stirred, and the stirring was stopped at t=1320s (22 minutes) to obtain the D solution.

[0092] <Processing steps> The beaker was removed from the cooling tank, and solution D was allowed to stand to allow the yellow solid to settle completely. The supernatant was then removed, and the yellow solid was washed with hydrofluoric acid at a concentration of approximately 24% by mass, followed by washing with methanol. The washed solid was filtered to separate and recover it, and the remaining methanol was removed by evaporation during drying. After drying, only the yellow powder that passed through a nylon sieve with a mesh size of 75 μm was classified and recovered. Based on the above, fluoride phosphor particles of Example 1 were obtained. The amount of fluoride phosphor particles obtained was 262 g.

[0093] [Example 2] Solution C3 was obtained by the same method as in steps (A), (B), and (C1) to (C3) in Example 1.

[0094] <Process (D)> (Process (D1)) At t=360s, 14g of 50R was added to solution C3 to obtain solution D1. (Process (D2)) At t=480s, 14g of 50R was added to solution D1 to obtain solution D2. (Process (D3)) At t=600s, 14g of 50R was added to solution D2 to obtain solution D3. The D3 solution was continuously stirred, and the stirring was stopped at t=1260s (21 minutes) to obtain the D solution.

[0095] The obtained solution D was treated in the same manner as in Example 1 to obtain the fluoride phosphor particles of Example 2. The amount of fluoride phosphor particles obtained was 255 g.

[0096] [Example 3] Solution B2 was obtained in the same manner as in steps (A) and (B) of Example 1, except that the amount of 5D added in step (B2) was 25 g.

[0097] <Process (C)> (Process (C1)) At t=180s, 3.0g of KMF and 14g of 50R were added to solution B2 to obtain solution C1. (Process (C2)) At t=240s, 3.0g of KMF was added to solution C1 to obtain solution C2. (Process (C3)) At t=300s, 3.0g of KMF and 14g of 50R were added to solution C2 to obtain solution C3.

[0098] <Process (D)> (Process (D1)) At t=420s, 14g of 50R was added to solution C3 to obtain solution D1. (Process (D2)) At t=540s, 14g of 50R was added to solution D1 to obtain solution D2. (Process (D3)) At t=660s, 14g of 50R was added to solution D2 to obtain solution D3. The D3 solution was continuously stirred, and the stirring was stopped at t=1320s (22 minutes) to obtain the D solution.

[0099] The obtained solution D was treated in the same manner as in Example 1 to obtain the fluoride phosphor particles of Example 3. The amount of fluoride phosphor particles obtained was 256 g.

[0100] [Example 4] <Process (A)> Solution A was obtained in the same manner as in step (A) of Example 1, except that the amount of KHF2 added was 300 g.

[0101] <Process (B)> Solution B2 was obtained by the same method as in step (B) of Example 1, except that the amount of KMF added in step (B1) was 8.0 g.

[0102] <Process (C)> Solution C2 was obtained by the same method as in steps (C1) and (C2) in Example 1.

[0103] <Process (D)> (Process (D1)) At t=240s, 14g of 50R was added to solution C2 to obtain solution D1. (Process (D2)) At t=360s, 14g of 50R was added to solution D1 to obtain solution D2. The D2 solution was continuously stirred, and the stirring was stopped at t=1200s (20 minutes) to obtain the D solution.

[0104] The obtained solution D was treated in the same manner as in Example 1 to obtain the fluoride phosphor particles of Example 4. The amount of fluoride phosphor particles obtained was 236 g.

[0105] [Example 5] Solution A was obtained using the same method as in step (A) of Example 1.

[0106] <Process (B)> When solution A reached 0°C, 7.0g of KMF and 15g of 5D were added to solution A to obtain solution B. This addition was defined as time t=0. Furthermore, stirring and cooling of the solution were continued until the end of stirring in step (D).

[0107] <Process (C)> (Process (C1)) At t=30s, 3.0g of KMF and 14g of 50R were added to solution B to obtain solution C1. (Process (C2)) At t=90s, 3.0g of KMF was added to solution C1 to obtain solution C2. (Process (C3)) At t=150s, 3.0g of KMF and 14g of 50R were added to solution C2 to obtain solution C3.

[0108] <Process (D)> (Process (D1)) At t=270s, 14g of 50R was added to solution C3 to obtain solution D1. (Process (D2)) At t=390s, 14g of 50R was added to solution D1 to obtain solution D2. (Process (D3)) At t=510s, 14g of 50R was added to solution D2 to obtain solution D3. The D3 solution was continuously stirred, and the stirring was stopped at t=1200s (20 minutes) to obtain the D solution.

[0109] The obtained solution D was treated in the same manner as in Example 1 to obtain the fluoride phosphor particles of Example 5. The amount of fluoride phosphor particles obtained was 238 g.

[0110] [Example 6] Except for using 3Y instead of 5D in step (B2), fluoride phosphor particles of Example 6 were obtained in the same manner as in Example 1. The amount of fluoride phosphor particles obtained was 273 g.

[0111] [Example 7] Fluoride phosphor particles of Example 7 were obtained in the same manner as in Example 2, except that 40R was used instead of 50R in steps (C1), (C3), and (D1) to (D3). The amount of fluoride phosphor particles obtained was 278 g.

[0112] [Comparative Example 1] Solution A was obtained using the same method as in step (A) of Example 1.

[0113] When solution A reached -7°C, 4.0g of KMF and 72g of 50R were added to solution A to obtain solution B. This addition was defined as time t=0. The stirring and cooling of the solution were continued until the end of stirring.

[0114] To solution B, 4.0 g of KMF was added at t=45s, then another 4.0 g of KMF at t=90s, and then another 4.0 g of KMF at t=135s. Stirring was then stopped at t=1500s (25 minutes) to obtain the solution.

[0115] The obtained solution was treated in the same manner as in Example 1 to obtain fluoride phosphor particles of Comparative Example 1. The amount of fluoride phosphor particles obtained was 239 g.

[0116] [measurement] The following describes the measurement methods for fluoride phosphor particles in each example and comparative example.

[0117] <Compositional analysis and Mn content of fluoride phosphor particles> The elemental composition of the fluoride phosphor particles of Examples 1-7 and Comparative Example 1 was analyzed by ICP emission spectroscopy for K, Si, and Mn, and by ion chromatography for F. Analysis revealed that the fluoride phosphor particles in Examples 1-7 and Comparative Example 1 all had a molar ratio of K, Si, and F equal to the stoichiometric ratio of 2:1:6 derived from the chemical formula K2SiF6. Therefore, it was determined that the fluoride phosphor particles in Examples 1-7 and Comparative Example 1 were all crystals of K2SiF6. Table 1 also shows the Mn content in the fluoride phosphor particles of Examples 1-7 and Comparative Example 1.

[0118] <Particle size measurement> 30 mL of ethanol was weighed into a 50 mL beaker, 0.03 g of fluoride phosphor particles were added, and the mixture was dispersed for 3 minutes using an ultrasonic homogenizer (manufactured by Nippon Seiki Seisakusho Co., Ltd., product name: Ultrasonic Homogenizer US-150E, settings: Altitude: 100%, Amplitude: 100%, oscillation frequency: 19.5 kHz, tip size: φ20, amplitude: 32 ± 2 μm) to prepare the measurement sample. Subsequently, a volume-based particle size distribution curve was obtained using a laser diffraction scattering particle size distribution analyzer (manufactured by Microtrac Bell Co., Ltd., product name: Microtrac MT3300EX II). From the obtained particle size distribution curve, D 10 (Cumulative 10% value), D 50 (Cumulative 50th percentile) and D 90 The (cumulative 90th percentile) was calculated. The obtained D 10 , D 50and D 90 From this, the span value (D 90 - D 10 ) / D 50 was calculated. D of the fluoride phosphor particles of Examples 1 to 7 and Comparative Example 1 10 , D 50 , D 90 , and the span value are shown in Table 1.

[0119] <Absorption rate, internal quantum efficiency, external quantum efficiency with respect to light of wavelength 455 nm> A standard reflector (manufactured by Labsphere, product name: Spectralon) with a reflectivity of 99% was set at the side opening (φ10 mm) of an integrating sphere (φ60 mm). Monochromatic light spectrally separated to a wavelength of 455 nm from a light-emitting light source (Xe lamp) was introduced into this integrating sphere by an optical fiber. Then, the spectrum of the reflected light was measured by a spectrophotometer (manufactured by Otsuka Electronics Co., Ltd., product name: QE-2000). At this time, the number of excitation photons (Qex) was calculated from the spectrum in the wavelength range of 450 to 465 nm.

[0120] Next, a concave cell filled with fluoride phosphor particles so that the surface was smooth was set at the opening of the integrating sphere. Then, the fluoride phosphor particles were irradiated with monochromatic light having a wavelength of 455 nm. Then, the spectra of the excitation reflected light and fluorescence were measured by a spectrophotometer. From the obtained spectral data, the number of excitation reflected photons (Qref) and the number of fluorescence photons (Qem) were calculated. The number of excitation reflected photons was calculated in the same wavelength range as the number of excitation photons, and the number of fluorescence photons was calculated in the wavelength range of 465 to 800 nm.

[0121] From the three types of photon numbers obtained, the following three characteristics were calculated. · Absorption rate (%): {(Qex - Qref) / Qex} × 100 · Internal quantum efficiency (%): {Qem / (Qex - Qref)} × 100 · External quantum efficiency (%): (Qem / Qex) × 100

[0122] Table 1 shows the absorption rate, internal quantum efficiency, and external quantum efficiency of the fluoride phosphor particles of Examples 1-7 and Comparative Example 1.

[0123] [Table 1]

[0124] Table 1 shows that the fluoride phosphor particles of the example have a smaller span value than the fluoride phosphor particles of the comparative example. In other words, the method for producing fluoride phosphor particles of this embodiment makes it possible to reduce the span value of the resulting fluoride phosphor particles.

Claims

1. Step (A) involves preparing solution A by mixing an aqueous solution of hydrogen fluoride with a K-containing raw material, Step (B) involves mixing the aforementioned liquid A, a Mn-containing raw material, and a first Si-containing raw material to obtain liquid B containing a seed crystal. A method for producing fluoride phosphor particles, comprising the step (C) of mixing a liquid containing the seed crystal, the Mn-containing raw material, and a second Si-containing raw material to obtain liquid C.

2. The volume-based median diameter (D) of the first Si-containing raw material ５０ ) is the volume-based median diameter (D) of the second Si-containing raw material. ５０ A method for producing fluoride phosphor particles according to claim 1, which are smaller than ).

3. The volume-based median diameter (D) of the first Si-containing raw material ５０ A method for producing fluoride phosphor particles according to claim 1 or 2, wherein the diameter of the particle is 1 μm or more and 20 μm or less.

4. The volume-based median diameter (D) of the second Si-containing raw material ５０ A method for producing fluoride phosphor particles according to claim 1 or 2, wherein the diameter of the particle is 20 μm or larger.

5. A method for producing fluoride phosphor particles according to claim 1 or 2, wherein the mass ratio (second / first) of the amount of the second Si-containing raw material mixed to the amount of the first Si-containing raw material mixed is 0.8 or more and 10.0 or less.

6. The aforementioned Mn-containing raw material is K ２ MnF ６ A method for producing fluoride phosphor particles according to claim 1 or 2, comprising the above.

7. The K-containing raw material is KHF. ２ A method for producing fluoride phosphor particles according to claim 1 or 2, comprising the above.

8. The first Si-containing raw material is SiO ２ A method for producing fluoride phosphor particles according to claim 1 or 2, comprising the above.

9. The second Si-containing raw material is SiO ２ The method for producing fluoride phosphor particles according to claim 1 or 2, which contains

10. The aforementioned step (C) is a step (C1) in which the Mn-containing raw material and the second Si-containing raw material are added to the liquid containing the seed crystal and stirred to obtain liquid C1, A method for producing fluoride phosphor particles according to claim 1 or 2, comprising the step (C2) of adding the Mn-containing raw material to the C1 liquid and stirring to obtain the C2 liquid.

11. The aforementioned step (B) is a step (B1) in which the Mn-containing raw material is added to the liquid A and stirred to obtain liquid B1, A method for producing fluoride phosphor particles according to claim 1 or 2, comprising the step (B2) of adding the first Si-containing raw material to the B1 liquid and stirring to obtain the B2 liquid.

12. A method for producing fluoride phosphor particles according to claim 1 or 2, further comprising the step (D) of mixing the aforementioned liquid C with the second Si-containing raw material to obtain liquid D.

13. The aforementioned step (D) is a step (D1) in which the second Si-containing raw material is added to the liquid C and stirred to obtain liquid D1, A method for producing fluoride phosphor particles according to claim 12, comprising the step (D2) of adding the second Si-containing raw material to the D1 liquid and stirring to obtain the D2 liquid.

14. The method for producing fluoride phosphor particles according to claim 1 or 2, wherein the composition of the fluoride phosphor particles is represented by the following general formula (1). General form (1): A ２ M （１－ｎ） F ６ Mn ４＋ ｎ (In the general formula (1) above, element A is one or more alkali metal elements containing K, and element M is Si in elemental form, Ge in elemental form, or a combination of Si and one or more elements selected from the group consisting of Ge, Sn, Ti, Zr, and Hf, where 0 < n ≤ 0.1)

15. D of the fluoride phosphor particles obtained by the following method ５０ , D １０ and D ９０ The span value (D) of the fluoride phosphor particles is calculated from the above. ９０ -D １０ ) / D ５０ A method for producing fluoride phosphor particles according to claim 1 or 2, wherein the ratio is 0.80 or less. [method] 30 mL of ethanol is weighed into a 50 mL beaker, 0.03 g of fluoride phosphor particles are added, and the mixture is dispersed using an ultrasonic homogenizer for 3 minutes to prepare the measurement sample. Then, a volume-based particle size distribution curve is obtained using a laser diffraction scattering particle size distribution analyzer. From the particle size distribution curve, D １０ (Cumulative 10% value), D ５０ (Cumulative 50th percentile) and D ９０ (Calculate the cumulative 90th percentile) and obtain the D １０ , D ５０ and D ９０ Therefore, the span value (D ９０ -D １０ ) / D ５０ Calculate.

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