Fluoride phosphor particles, composites, and light-emitting devices

Abstract

This invention provides fluoride phosphor particles with improved external quantum efficiency. [Solution] A fluoride phosphor particle whose composition is represented by a predetermined general formula, wherein when the cross-section of the fluoride phosphor particle is elementally analyzed by a predetermined method, the cross-section of the fluoride phosphor particle has a first region which is the outermost region and has a low Mn concentration, a second region which is inward of the first region and has a high Mn concentration, and a third region which is inward of the second region and has a low Mn concentration, wherein the area of ​​the second region is the largest among the group consisting of the first region, the second region, and the third region.

Description

Technical Field

[0001] The present invention relates to fluoride phosphor particles, composites, and light-emitting devices.

Background Art

[0002] Fluoride phosphor particles are used, for example, as wavelength conversion members in light-emitting diodes and the like. Examples of technologies related to fluoride phosphor particles include the technology described in Patent Document 1.

[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 the steps of preparing an aqueous solution in which element A and fluorine are dissolved in a solvent, and adding a manganese compound that supplies solid silicon dioxide and manganese other than +7 valent manganese 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 fluoride phosphor particles with improved external quantum efficiency.

Means for Solving the Problems

[0006] According to the present invention, the following fluoride phosphor particles, composites, and light-emitting devices are provided.

[0007] [1] Fluoride phosphor particles whose composition is represented by the following general formula (1), Using an electron beam probe microanalyzer, with an acceleration voltage of 15kV and an irradiation current of 5×10⁻¹⁰, -8 A. When the cross-section of the fluoride phosphor particles was subjected to elemental analysis under the following conditions: measurement time 30 ms, measurement area size 160 × 160 μm, and number of measurement points 400 × 400 pixels, In the cross-section of the fluoride phosphor particle, the outermost region is a first region with a low Mn concentration, In the cross-section of the fluoride phosphor particle, a second region is located inside the first region and has a high Mn concentration. The cross-section of the fluoride phosphor particle has a third region which is inside the second region and has a lower Mn concentration, A fluoride phosphor particle comprising the group consisting of the first region, the second region, and the third region, wherein the area of ​​the second region is the largest. General formula (1): A2M (1-n) F6:Mn 4+ n (In general formula (1), 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, 0 <n≦0.1である。) [2] The fluoride phosphor particle according to [1], wherein the proportion of the area of ​​the second region is 50% or more when the sum of the areas of the first region, the second region, and the third region is taken as 100%. [3] The fluoride phosphor particle according to [1] or [2], wherein the area ratio of the second region to the third region (second / third) is 10 or more. [4] The average value Pa1 of the Mn level in the first region is less than 75% of the average value Pa of the Mn level across the entire cross-section of the fluoride phosphor particles. The average value Pa2 of the Mn level in the second region is 75% or more of the average value Pa of the Mn level across the entire cross-section of the fluoride phosphor particles. The average value Pa3 of the Mn level in the third region is less than 75% of the average value Pa of the Mn level across the entire cross-section of the fluoride phosphor particles. The fluoride phosphor particles according to any one of [1] to [3]. [5] The ratio (Pa2 / Pa3) of the average value Pa2 of the Mn level in the second region to the average value Pa3 of the Mn level in the third region is 1.50 or more. The fluoride phosphor particles according to any one of [1] to [4]. [6] The fluoride phosphor particles according to any one of [1] to [5], having a Mn content based on ICP emission spectrometry of 0.5 mass% or more and 1.5 mass% or less. [7] The span value (D 50 , D 10 and D 90 ) of the fluoride phosphor particles calculated from is 0.80 or less. The fluoride phosphor particles according to any one of [1] to [6]. 90 -D 10 ) / D 50 [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, using a laser diffraction scattering type particle size distribution measuring device, 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 determined, and from the obtained D 10 , D 50 and D 90 , the span value (D 90 -D​10 ) / D 50 Calculate. [8] A fluoride phosphor particle according to any one of [1] to [7] above, wherein the external quantum efficiency when irradiated with light of a wavelength of 455 nm is 66.0% or higher. [9] A composite comprising fluoride phosphor particles as described in any of [1] to [8] above, and a sealing material for sealing the fluoride phosphor particles.

[10] A light-emitting device comprising a light-emitting element that emits excitation light, and the composite [9] described above that converts the wavelength of the excitation light. [Effects of the Invention]

[0008] According to the present invention, fluoride phosphor particles with improved external quantum efficiency can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing an example of a light-emitting device. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. Note that the drawings are simplified diagrams and do not correspond to the actual dimensional ratios. 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.

[0011] Light-emitting devices are known to include composites containing fluoride phosphor particles. Such light-emitting devices are required to have sufficient brightness (total luminous flux) while also having small variations in chromaticity. 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.

[0012] 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.

[0013] The fluoride phosphor particles of this embodiment can improve external quantum efficiency. Furthermore, the fluoride phosphor particles of this embodiment can reduce the span value. Therefore, according to the light-emitting device containing fluoride phosphor particles of this embodiment, the total luminous flux of the light-emitting device can be improved and the variation in the chromaticity of the light-emitting device can be reduced.

[0014] [Fluoride phosphor particles] The fluoride phosphor particles of this embodiment are fluoride phosphor particles whose composition is represented by the following general formula (1), and are measured using an electron beam probe microanalyzer with an acceleration voltage of 15kV and an irradiation current of 5×10⁻¹⁰ -8 A. When the cross-section of a fluoride phosphor particle is elementally analyzed under the conditions of a measurement time of 30 ms, a measurement area size of 160 × 160 μm, and a measurement point count of 400 × 400 pixels, the cross-section of the fluoride phosphor particle has three regions: a first region which is the outermost region and has a low Mn concentration; a second region which is inside the first region and has a high Mn concentration; and a third region which is inside the second region and has a low Mn concentration. Of the group consisting of the first, second, and third regions, the area of ​​the second region is the largest. General formula (1): A2M (1-n) F6:Mn 4+ n

[0015] In general formula (1), 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, 0 <n≦0.1である。

[0016] According to our research, we have found that the external quantum efficiency of fluoride phosphor particles can be improved by having a specific Mn distribution in the cross-section of the fluoride phosphor particles. Specifically, a fluoride phosphor particle having a first region, a second region, and a third region in its cross-section, and in which the area of ​​the second region is the largest among the group consisting of the first, second, and third regions, can improve the external quantum efficiency of the fluoride phosphor particle.

[0017] In order to bring the Mn distribution of the fluoride phosphor particles in this embodiment within the scope of the present invention, it is important to adjust the conditions for manufacturing the fluoride phosphor particles, for example. Specifically, it is important to manufacture the fluoride phosphor particles by a manufacturing method including steps (A) to (D) described later; to use two types of Si-containing raw materials with different particle sizes as raw materials; to adjust the particle size of the Si-containing raw materials to an appropriate range; and to add each raw material in an appropriate order.

[0018] In this embodiment, a low Mn concentration in the first and third regions means that the Mn concentration is at least lower than that in the second region. In this embodiment, a high Mn concentration in the second region means that the Mn concentration is at least higher than that in the first and third regions.

[0019] The Mn concentration in the cross-section of the fluoride phosphor particles in this embodiment was determined using an electron beam probe microanalyzer with an acceleration voltage of 15 kV and an irradiation current of 5 × 10⁻¹⁰ -8 A. It can be evaluated by the Mn level at various points in the cross-section obtained when elemental analysis is performed on a cross-section of a fluoride phosphor particle under the conditions of a measurement time of 30 ms, a measurement area size of 160 × 160 μm, and a measurement point count of 400 × 400 pixels.

[0020] For example, the JXA-8230, manufactured by JEOL Ltd., can be used as an electron beam probe microanalyzer. Additionally, the accompanying software can be used as appropriate for elemental analysis of cross-sections of fluoride phosphor particles.

[0021] The Mn level is an index that quantitatively represents the characteristic X-ray intensity of Mn in the measurement area on the surface of the object being measured. Although the unit of the Mn level is not mol% or mass%, the Mn level value has a positive correlation with the actual amount of Mn present, so the amount of Mn can be discussed using the Mn level value.

[0022] In other words, the first region of the fluoride phosphor particle in this embodiment is the outermost region in the cross-section of the fluoride phosphor particle, and is mainly composed of areas with a small Mn level; the second region is the region in the cross-section of the fluoride phosphor particle that is inward of the first region, and is mainly composed of areas with a large Mn level; and the third region is the region inward of the cross-section of the fluoride phosphor particle that is inward of the second region, and is mainly composed of areas with a small Mn level.

[0023] The average value Pa of the Mn level across the entire cross-section of the fluoride phosphor particles in this embodiment is preferably 12 to 35, more preferably 14 to 30, and even more preferably 16 to 25.

[0024] In this embodiment, the fluoride phosphor particles preferably have the following characteristics: the average value Pa1 of the Mn level in the first region is less than 75% of the average value Pa of the Mn level across the entire cross-section of the fluoride phosphor particles; the average value Pa2 of the Mn level in the second region is 75% or greater of the average value Pa of the Mn level across the entire cross-section of the fluoride phosphor particles; and the average value Pa3 of the Mn level in the third region is less than 75% of the average value Pa of the Mn level across the entire cross-section of the fluoride phosphor particles.

[0025] The following sections will explain each of the three domains.

[0026] <First area> The first region in this embodiment is the outermost region in the cross-section of the fluoride phosphor particles, and is a region with a low Mn concentration.

[0027] The average value Pa1 of the Mn level in the first region of this embodiment is preferably 18 or less, more preferably 15 or less, and even more preferably 13 or less, and the lower limit is not particularly limited, but may be, for example, 6 or more, or 8 or more.

[0028] In this embodiment, the ratio of the area of ​​the first region is preferably 40% or less, more preferably 35% or less, and even more preferably 32% or less, when the sum of the areas of the first region, the second region, and the third region is taken as 100%. The lower limit is not particularly limited, but may be, for example, 10% or more, or 15% or more. Furthermore, it is preferable that the ratio of the area of ​​the first region to the total cross-sectional area of ​​the fluoride phosphor particles, when the total cross-sectional area of ​​the fluoride phosphor particles is taken as 100%, is also within the above numerical range.

[0029] <Second area> The second region in this embodiment is a region in the cross-section of the fluoride phosphor particles that is inside the first region and has a high Mn concentration.

[0030] In this embodiment, the average value Pa2 of the Mn level in the second region is preferably 15 or higher, more preferably 18 or higher, and even more preferably 20 or higher, from the viewpoint of further improving the external quantum efficiency. The upper limit is not particularly limited, but may be, for example, 60 or less, or 40 or less.

[0031] In this embodiment, the average value Pa2 of the Mn level in the second region is preferably 5 or more, more preferably 7 or more, and even more preferably 9 or more, than the average value Pa3 of the Mn level in the third region. If the difference between Pa2 and Pa3 is greater than or equal to the lower limit mentioned above, the external quantum efficiency of the fluoride phosphor particles can be further improved, and the span value of the fluoride phosphor particles can be made smaller.

[0032] The ratio of the average Mn level Pa2 of the second region to the average Mn level Pa3 of the third region (Pa2 / Pa3) is preferably 1.50 or higher, more preferably 1.80 or higher, and even more preferably 2.00 or higher. The upper limit is not particularly limited, but may be, for example, 4.00 or lower, 3.50 or lower, or 3.20 or lower. If the ratio of the average Mn level Pa2 of the second region to the average Mn level Pa3 of the third region (Pa2 / Pa3) is greater than or equal to the above lower limit, the external quantum efficiency of the fluoride phosphor particles can be further improved, and the span value of the fluoride phosphor particles can be further reduced.

[0033] In this embodiment, the ratio of the area of ​​the second region is preferably 50% or more, more preferably 60% or more, and even more preferably 65% ​​or more, when the sum of the areas of the first region, the second region, and the third region is taken as 100%, from the viewpoint of further improving the external quantum efficiency. The upper limit is not particularly limited, but may be, for example, 85% or less, or 80% or less. Furthermore, it is preferable that the ratio of the area of ​​the second region to the total cross-sectional area of ​​the fluoride phosphor particles, when the total cross-sectional area of ​​the fluoride phosphor particles is taken as 100%, is also within the above numerical range.

[0034] The area ratio of the second region to the third region (second / third) is preferably 10 or more, more preferably 15 or more, and even more preferably 20 or more. The upper limit is not particularly limited, but may be 250 or less, 200 or less, or 180 or less. If the area ratio of the second region to the third region (second / third) is greater than or equal to the above lower limit, the external quantum efficiency of the fluoride phosphor particles can be further improved.

[0035] <Third area> The third region in this embodiment is a region located inside the second region and has a low Mn concentration.

[0036] The average value Pa3 of the Mn level in the third region of this embodiment is preferably 18 or less, more preferably 15 or less, and even more preferably 12 or less, and the lower limit is not particularly limited, but may be, for example, 6 or more, or 7 or more.

[0037] In this embodiment, the area ratio of the third region is preferably 10% or less, more preferably 8% or less, and even more preferably 5% or less, when the sum of the areas of the first, second, and third regions is 100%, from the viewpoint of reducing the span value of the fluoride phosphor particles. The lower limit is not particularly limited, but may be, for example, 0.2% or more, or 0.4% or more. Furthermore, it is preferable that the ratio of the area of ​​the third region to the total cross-sectional area of ​​the fluoride phosphor particles, when the total cross-sectional area of ​​the fluoride phosphor particles is taken as 100%, is also within the above numerical range.

[0038] Here, the average value Pa of the Mn level across the entire cross-section of the fluoride phosphor particles, the average value of the Mn level in the first to third regions (Pa1 to Pa3), and the area ratio of the first to third regions refer to the values ​​calculated by the method described in the examples (the average values ​​in Table 1).

[0039] The composition of the fluoride phosphor particles in this embodiment is represented by general formula (1). General formula (1): A2M (1-n) F6:Mn 4+ n

[0040] 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。

[0041] In general formula (1), element A is one or more alkali metal elements containing K. Element A is, for example, a combination of at least one alkali metal element selected from the group consisting of K and at least one of Li, Na, Rb, and Cs. From the viewpoint of further improving chemical stability, 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 elemental K.

[0042] In general formula (1), element M is elemental Si, elemental Ge, or a combination of one or more elements selected from the group consisting of Si and one or more of Ge, Sn, Ti, Zr, and Hf. From the viewpoint of further improving chemical stability, 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 elemental Si.

[0043] In general formula (1), 0 < n ≤ 0.1, and from the viewpoint of further improving luminescence characteristics, preferably 0.015 ≤ n ≤ 0.04.

[0044] D of the fluoride phosphor particles of this 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.

[0045] D of the fluoride phosphor particles of this 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.

[0046] D of the fluoride phosphor particles of this embodiment 90The particle size is preferably 20.0 μm to 55.0 μm, more preferably 25.0 μm to 50.0 μm, and even more preferably 27.0 μm to 45.0 μm.

[0047] The fluoride phosphor particles of this embodiment are D 50 , D 10 and D 90 The 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.

[0048] 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.

[0049] [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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] The external quantum efficiency of the fluoride phosphor particles in this embodiment for light with a wavelength of 455 nm is preferably 66.0% or higher, more preferably 66.5% or higher, and the upper limit is not particularly limited, but may be, for example, 80.0% or lower, or 75.0% or lower.

[0054] 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.

[0055] [Method for producing fluoride phosphor particles] A preferred embodiment of the method for producing fluoride phosphor particles according to this embodiment will be described.

[0056] The method for producing fluoride phosphor particles according to this embodiment preferably includes 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; (C) mixing the solution containing the seed crystal, a Mn-containing raw material, and a second Si-containing raw material to obtain solution C; and (D) mixing solution C and a second Si-containing raw material to obtain solution D.

[0057] In the method for producing fluoride phosphor particles of the present embodiment, in step (B), a seed crystal is obtained by using a first Si-containing raw material. Since the first Si-containing raw material has a small particle size and dissolves quickly, and the seed crystal precipitates immediately, the amount of Mn incorporated into the seed crystal is limited. Therefore, it is considered that a third region with a low Mn concentration is formed in the obtained fluoride phosphor particles. Next, in step (C), by using a Mn-containing raw material and a second Si-containing raw material having a large particle size and slow dissolution, the seed crystal gradually grows while incorporating Mn. Therefore, in the obtained fluoride phosphor particles, it is considered that a second region with a large area and a high Mn concentration is formed. Further, in step (D), by using the second Si-containing raw material without using the Mn-containing raw material, crystal growth occurs while reducing the amount of Mn incorporated. Therefore, in the obtained fluoride phosphor particles, it is considered that a first region with a low Mn concentration is formed.

[0058] Each raw material in the method for producing fluoride phosphor particles of the present embodiment will be described.

[0059] <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.

[0060] <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 at least one selected from the group consisting of, for example, water-soluble potassium salts such as KHF2, KF, KOH, KCl, KBr, KI, potassium acetate, and K2CO3, and preferably includes KHF2.

[0061] <Mn-containing raw material> The Mn-containing raw material in this embodiment is not particularly limited and can be any compound that can supply manganese atoms. 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.

[0062] 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.

[0063] 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.

[0064] <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.

[0065] The median diameter (D) of the first Si-containing raw material of this embodiment, based on volume. 50The 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 within the above range, it becomes easier to form a third region with a low Mn concentration in the resulting fluoride phosphor particles.

[0066] <Second Si-containing raw material> The second Si-containing raw material of this embodiment has a median diameter (D) by volume that is greater than that of the first Si-containing raw material. 50 This refers to a raw material with a large amount 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.

[0067] 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.

[0068] The volume-based median diameter (D) of the second Si-containing raw material in this embodiment 50 The particle size 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. 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. The second Si-containing raw material is D 50 If the value is above the lower limit mentioned above, the seed crystal will gradually grow while incorporating Mn, making it easier to form a second region with a larger area and higher Mn concentration in the resulting fluoride phosphor particles.

[0069] 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. When the above mass ratio (second / first) is greater than or equal to the above lower limit, the resulting fluoride phosphor particles tend to form a second region with a larger area and higher Mn concentration. When the above mass ratio (second / first) is less than or equal to the above upper limit, the resulting fluoride phosphor particles tend to form a third region with a lower Mn concentration. 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.

[0070] 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.

[0071] [Median diameter (D) of Si-containing raw material by volume] 50 ) Measurement method] 100 mL of filtered water containing 0.001% by mass of sodium hexametaphosphate is weighed into a 200 mL beaker, 0.03 g of Si-containing raw material is added, and the sample is dispersed using an ultrasonic homogenizer for 3-4 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 obtained particle size distribution curve, the D of the Si-containing raw material is determined. 50 (Calculate the cumulative 50th percentile value) and determine the median diameter (D) based on volume. 50 )

[0072] The following describes in detail each step of the method for producing fluoride phosphor particles according to this embodiment.

[0073] <Process (A)> The method for producing fluoride phosphor particles according to this embodiment preferably includes step (A) of preparing solution A by mixing an aqueous solution of hydrogen fluoride with a K-containing raw material.

[0074] In step (A), the method for preparing solution A is not particularly limited, but one example is to prepare solution A by adding a K-containing raw material to a beaker containing an aqueous solution of hydrogen fluoride and stirring it with a magnetic stirrer.

[0075] <Process (B)> The method for producing fluoride phosphor particles according to this embodiment preferably 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.

[0076] 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. 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.

[0077] In process (B), solution B refers to the solution obtained at the end of process (B). Furthermore, solution B contains seed crystals. Seed crystals refer to the crystals that precipitate as the first Si-containing raw material dissolves.

[0078] <Process (C)> The method for producing fluoride phosphor particles according to this embodiment preferably 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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. When the mass ratio is within the above numerical range, the resulting fluoride phosphor particles tend to form a second region with a large area and high Mn concentration, and a third region containing Mn but with a low Mn concentration, while suppressing concentration quenching.

[0083] In process (C), solution C refers to the solution obtained at the end of process (C).

[0084] <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.

[0085] 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.

[0086] <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.

[0087] In each step, conditions such as stirring temperature, stirring time, and the interval between the addition of each raw material can be appropriately set, for example, by referring to the conditions described in the examples.

[0088] [Complex and light-emitting devices] The composite of this embodiment comprises the fluoride phosphor particles of this embodiment and a sealing material for sealing the fluoride phosphor particles. The light-emitting device of this embodiment comprises a light-emitting device that emits excitation light and a composite device of this embodiment that converts the wavelength of the excitation light.

[0089] Figure 1 is a schematic diagram showing an example of a light-emitting device. The light-emitting device 1 comprises a composite 10 and a light-emitting element 20. The composite 10 is provided in contact with the upper part of the light-emitting element 20. The light-emitting element 20 is, for example, a blue LED. There are terminals on the bottom of the light-emitting element 20. When these terminals are connected to a power supply, the light-emitting element 20 can emit light. The excitation light emitted from the light-emitting element 20 is wavelength-converted by the composite 10. If the excitation light is blue light, the blue light is wavelength-converted to red light by the composite 10 containing phosphor powder.

[0090] The composite 10 comprises the fluoride phosphor particles of this embodiment and a sealing material for sealing the fluoride phosphor particles. The sealing material can be, for example, various curable resin materials (materials that harden with heat and / or light). The curable resin material is preferably sufficiently transparent and possesses the optical properties required for displays and lighting devices. The resin material includes, for example, at least one selected from the group consisting of silicone resin materials, epoxy resin materials, urethane resin materials, etc. Preferably, it includes a silicone resin material from the viewpoint of high transparency and excellent heat resistance. The amount of phosphor powder particles in the composite 10 is, for example, 10% by mass or more and 70% by mass or less, preferably 25% by mass or more and 55% by mass or less.

[0091] The shape and the like of the light-emitting element 20 are not particularly limited, and any shape may be adopted depending on the use of the light-emitting device 1.

[0092] The light-emitting device 1 can be applied to, for example, smartphones, displays, and the like.

[0093] As described above, the embodiments of the present invention have been described, but these are examples of the present invention, and various configurations other than those described above can also be adopted. Further, the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. within the scope that can achieve the object of the present invention are included in the present invention.

Examples

[0094] Hereinafter, the present embodiment will be described in detail based on examples and comparative examples. Note that the present embodiment is not limited to the descriptions of these examples.

[0095] [Raw materials] The raw materials used in the examples and comparative examples will be described.

[0096] The abbreviations of the raw materials in the examples and comparative examples indicate that the following materials were used. HF: Aqueous hydrogen fluoride 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 50R: SiO2, FB-50R (manufactured by Denka Co., Ltd.), D 50 : 55.1 μm

[0097] <Measurement method of the median diameter (D 50 ) of SiO2 on a volume basis> 100 mL of filtered water containing 0.001% by mass of sodium hexametaphosphate was weighed into a 200 mL beaker, and 0.03 g of SiO2 was added to it. The sample was then dispersed 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) for 3 to 4 minutes 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: Microtrac MT3300EX II). From the obtained particle size distribution curve, the D of SiO2 was determined. 50 (Calculate the cumulative 50th percentile value) and determine the median diameter (D) based on volume. 50 )

[0098] [Example 1] <Process (A)> At room temperature, 2100 mL of HF was placed in a fluororesin beaker. The beaker was then immersed in antifreeze in a cooling bath containing antifreeze to cool it down. 260 g of KHF2 was added, and the mixture was thoroughly stirred using a magnetic stirrer. A homogeneous solution (Solution A) was obtained.

[0099] <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.

[0100] <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.

[0101] <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.

[0102] <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.

[0103] [Example 2] Solution C3 was obtained by the same method as in steps (A), (B), and (C1) to (C3) in Example 1.

[0104] <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.

[0105] 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.

[0106] [Example 3] <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.

[0107] <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.

[0108] <Process (C)> Solution C2 was obtained by the same method as in steps (C1) and (C2) in Example 1.

[0109] <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.

[0110] 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 236 g.

[0111] [Example 4] Solution A was obtained using the same method as in step (A) of Example 1.

[0112] <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).

[0113] <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.

[0114] <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.

[0115] 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 238 g.

[0116] [Example 5] Solution A was obtained using the same method as in step (A) of Example 1.

[0117] <Process (B)> When solution A reached 0°C, 8.0g of KMF and 30g 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).

[0118] <Process (C)> (Process (C1)) At t=60s, 3.5g of KMF and 14g of 50R were added to solution B to obtain solution C1. (Process (C2)) At t=120s, 3.5g of KMF was added to solution C1 to obtain solution C2. (Process (C3)) At t=180s, 3.5g of KMF and 14g of 50R were added to solution C2 to obtain solution C3.

[0119] <Process (D)> (Process (D1)) At t=300s, 14g of 50R was added to solution C3 to obtain solution D1. (Process (D2)) At t=420s, 14g of 50R was added to solution D1 to obtain solution D2. (Process (D3)) At t=540s, 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.

[0120] 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 266 g.

[0121] [Comparative Example 1] Solution A was obtained using the same method as in step (A) of Example 1.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] [measurement] The following describes the measurement methods for fluoride phosphor particles in each example and comparative example.

[0126] <Compositional analysis of all fluoride phosphor particles and Mn content> The elemental composition of the fluoride phosphor particles of Examples 1-5 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 1-5 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 1-5 and Comparative Example 1 were all crystals of K2SiF6. Table 2 also shows the Mn content in the fluoride phosphor particles of Examples 1-5 and Comparative Example 1.

[0127] <Elemental analysis of cross-sections of fluoride phosphor particles> (Cross-sectional processing of particles) Fluoride phosphor particles were embedded in embedding epoxy resin (G2 epoxy). The cross-sections of the fluoride phosphor particles were then exposed by ion milling using a cross-section polisher (CP). Subsequently, the cross-sections of the fluoride phosphor particles were coated with osmium. More specific procedures and conditions are shown below.

[0128] (resin embedding) (i) Place the sample into the recesses of the silicone embedding plate (which has 12 x 5 x 3 mm recesses), filling each recess to the brim. Typically, about 0.2 g of sample fits into one recess. (ii) A heat-curing two-part epoxy resin (G2 epoxy manufactured by Gatan Co., Ltd.), heated to 80°C, is dropped into the depressions of the silicone embedding plate. The amount of epoxy resin used at this time is usually about 0.2 to 0.3 g. The sample and epoxy resin are then lightly mixed with a toothpick. (iii) Degass the area using a vacuum impregnation device under conditions of -100kPa for a total of 5 to 10 minutes. (iv) Using a dryer, heat at 90°C for 90 minutes, then at 130°C for another 30 minutes. (v) Remove the sample (cured material) formed by the hardening of the epoxy resin from the recess.

[0129] (Milling) The sample (cured material) prepared by the resin embedding method described above has areas where the particles are dense (closer to the bottom of the recess in the silicone embedding plate) and areas where the particles are sparse (further from the bottom of the recess in the silicone embedding plate) due to particle sedimentation before the epoxy resin fully hardens. For elemental mapping, it is preferable to cut out a portion where the particles are monodisperse and moderately dense. Therefore, the argon ion beam was irradiated so that it struck the side of the sample (cured material) where the particles were dense (closer to the bottom of the recess in the silicone embedding plate). The equipment used was the IM4000, IM4000Plus, or ArBlade5000, all manufactured by Hitachi High-Tech Corporation. The acceleration voltage was 6kV, and the processing time was approximately 2-5 hours. Incidentally, the processing time was adjusted so that 1 / 2 to 2 / 3 of the thickness of the sample (cured material) prepared by the resin embedding method described above could be removed. Specifically, with an acceleration voltage of 6kV, the optimal processing time was 5 hours when using the IM4000, 3 hours when using the IM4000Plus, and 2 hours when using the ArBlade5000. By milling under the above conditions, a recess was formed by removing a portion of the side surface in the denser part of the sample (hardened material) (the part closest to the bottom of the recess in the silicone embedding plate) in the depth direction. The following elemental analysis (elemental mapping) was performed on that recess.

[0130] (Elemental analysis) Elemental analysis was performed on cross-sections of fluoride phosphor particles embedded in the cured epoxy resin prepared as described above, using an electron probe microanalyzer (JEOL Ltd., product name: JXA-8230) and its accompanying software. Mn level data was then obtained at each measurement point. The detailed measurement conditions were as follows: • Acceleration voltage: 15kV ·Irradiation current: 5×10 -8 A • Measurement time: 30ms • Measurement area size: 160 × 160 μm • Number of measurement points: 400 x 400 pixels Based on the size of the measurement area and the number of measurement points described above, in this embodiment, the Mn level was measured with a 0.4 × 0.4 μm area defined as 1 pixel. The measured value of the Mn level is expressed as a non-negative integer, and a larger Mn level number indicates a higher Mn concentration.

[0131] (Analysis of Mn distribution in particle cross-section) The EPMA images obtained from elemental analysis were analyzed using Microsoft Excel software. First, the outermost periphery of the cross-section of the fluoride phosphor particles was determined from the EPMA image obtained by elemental analysis. Specifically, near the boundary between the cross-section of the fluoride phosphor particles and the cured epoxy resin used for embedding, regions with a Mn level of 6 or higher were considered to be the cross-section of the fluoride phosphor particles, and regions with a Mn level of 5 or lower were considered to be the cured epoxy resin used for embedding, thereby determining the outermost periphery of the cross-section of the fluoride phosphor particles.

[0132] The cross-section of the fluoride phosphor particle was defined as the region inside the outermost edge of the cross-section, and the Mn level was counted. Note that even within a portion of the region inside the outermost edge of the fluoride phosphor particle's cross-section, there were pixels with a Mn level of 5 or less; the Mn level was counted for these pixels.

[0133] The average value Pa of the Mn level was determined across the entire cross-section of the fluoride phosphor particle. The average value Pa of the Mn level is calculated using the formula: Pa = sum of the Mn levels of all pixels in the cross-section of the fluoride phosphor particle / total number of pixels in the cross-section of the fluoride phosphor particle.

[0134] In the cross-section of the fluoride phosphor particles, each pixel was divided into pixel(a) and pixel(b) based on the following criteria using Microsoft Excel software. • pixel(a): A pixel with a Mn level less than 75% of the average Pa value of the Mn level. • pixel(b): A pixel with a Mn level greater than or equal to 75% of the average value Pa of the Mn level.

[0135] The distinction between pixel(a) and pixel(b) can be explained in detail as follows: For example, if the average Pa of the Mn level is 20, then 75% of the average Pa of the Mn level is 15. Therefore, each pixel is divided into pixel(a) and pixel(b) based on the following criteria. pixel(a): Pixel with a Mn level less than 15 pixel(b): A pixel with a Mn level of 15 or higher.

[0136] In the cross-section of the fluoride phosphor particles, the outermost region, mainly composed of pixel(a), was considered the first region; the region inside the first region, mainly composed of pixel(b), was considered the second region; and the region inside the second region, mainly composed of pixel(a), was considered the third region. These three regions were thus separated.

[0137] The number of pixels in the first to third regions was counted. The proportion of pixels in the first region, the second region, and the third region was calculated, relative to the total number of pixels in all three regions (which is set to 100%). Since the number of pixels can be considered as the area of ​​a region, this means we have calculated the ratio of the areas of the first to third regions to the sum of the areas of the first to third regions.

[0138] Furthermore, the fluoride phosphor particles in Examples 1 to 5 all consisted only of a first region, a second region, and a third region. That is, the total number of pixels in the first to third regions was the same as the total number of pixels in the cross-section of the fluoride phosphor particle.

[0139] The average values ​​of the Mn levels in the first to third regions (Pa1 to Pa3) were calculated based on the following formulas. • The average value of the Mn level in the first region, Pa1 = sum of the Mn levels of all pixels in the first region / total number of pixels in the first region. • The average value of the Mn level in the second region, Pa2 = sum of the Mn levels of all pixels in the second region / total number of pixels in the second region. • The average value of the Mn level in the third region, Pa3 = sum of the Mn levels of all pixels in the third region / total number of pixels in the third region

[0140] Note that some pixels corresponding to pixel(a) exist within the second region, but they will be considered pixels of the second region. Similarly, some pixels corresponding to pixel(b) exist within either the first or third region, but they will be considered pixels of the first or third region.

[0141] Table 1 shows the total number of pixels across the entire cross-section of the fluoride phosphor particles in Examples 1 to 5, the average Mn level Pa across the entire cross-section of the fluoride phosphor particles, the number of pixels in the first to third regions, the average Mn level (Pa1 to Pa3) in the first to third regions, and the area ratio of the first to third regions to the sum of the areas of the first to third regions.

[0142] The fluoride phosphor particles of Comparative Example 1 were composed primarily of pixels (b) across their entire cross-section. That is, the Mn in the fluoride phosphor particles of Comparative Example 1 was distributed almost uniformly across the entire cross-section, making it impossible to divide them into the first to third regions as defined in this specification. Therefore, Table 1 only shows the total number of pixels across the entire cross-section of the fluoride phosphor particles and the average value Pa of the Mn level across the entire cross-section of the fluoride phosphor particles for Comparative Example 1.

[0143] Here, the above analysis was performed on two particles per level. Therefore, Table 1 shows the analysis values ​​for each particle and their average values. For the total number of pixels across the cross-section of the fluoride phosphor particles, the average Mn level Pa across the cross-section of the fluoride phosphor particles, the number of pixels in the first to third regions, and the average Mn level (Pa1~Pa3) in the first to third regions, the average values ​​listed are the arithmetic mean of particles 1 and 2. For the ratio of the area of ​​the first to third regions to the sum of the areas of the first to third regions, the average value listed is calculated from the average total number of pixels across the cross-section of the fluoride phosphor particles and the average number of pixels in the first to third regions.

[0144] <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 50 and D 90 Therefore, the span value (D 90 -D 10 ) / D 50 The result was calculated. D of fluoride phosphor particles in Examples 1-5 and Comparative Example 1 10 , D 50 , D 90 The span values ​​are shown in Table 2.

[0145] <Absorptive rate, internal quantum efficiency, and external quantum efficiency for light with a wavelength of 455 nm> A standard reflector with a reflectivity of 99% (Labsphere, product name: Spectralon) was placed in the side opening (φ10 mm) of an integrating sphere (φ60 mm). Monochromatic light, spectrally separated to a wavelength of 455 nm from a light source (Xe lamp), was introduced into this integrating sphere via an optical fiber. The spectrum of the reflected light was then measured using a spectrophotometer (Otsuka Electronics Co., Ltd., product name: QE-2000). The number of excitation photons (Qex) was calculated from the spectrum in the wavelength range of 450 to 465 nm.

[0146] Next, a concave cell filled with fluoride phosphor particles to create a smooth surface was placed in the opening of an integrating sphere. The fluoride phosphor particles were then irradiated with monochromatic light at a wavelength of 455 nm. The spectra of the excited reflected light and fluorescence were then measured using a spectrophotometer. From the obtained spectral data, the number of excited reflected photons (Qref) and the number of fluorescent photons (Qem) were calculated. The number of excited reflected photons was calculated in the same wavelength range as the number of excited photons, and the number of fluorescent photons was calculated in the wavelength range of 465 to 800 nm.

[0147] From the three types of photon counts 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

[0148] Table 2 shows the absorption rate, internal quantum efficiency, and external quantum efficiency of the fluoride phosphor particles of Examples 1-5 and Comparative Example 1.

[0149] [Table 1]

[0150] [Table 2]

[0151] Table 2 shows that the fluoride phosphor particles of the example exhibit improved external quantum efficiency compared to the fluoride phosphor particles of the comparative example. In other words, the fluoride phosphor particles of this embodiment can improve external quantum efficiency.

[0152] Furthermore, as can be seen from Table 2, 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 fluoride phosphor particles of this embodiment can provide fluoride phosphor particles with a small span value. [Explanation of Symbols]

[0153] 1. Light-emitting device 10 complex 20 Light-emitting elements

Claims

1. Fluoride phosphor particles whose composition is represented by the following general formula (1), Using an electron beam probe microanalyzer, with an acceleration voltage of 15 kV and an irradiation current of 5 × 10⁻¹⁰, －８ A. When the cross-section of the fluoride phosphor particles was elementally analyzed under the following conditions: measurement time 30 ms, measurement area size 160 × 160 μm, and number of measurement points 400 × 400 pixels, In the cross-section of the fluoride phosphor particle, the outermost region is a first region with a low Mn concentration, In the cross-section of the fluoride phosphor particle, a second region is located inside the first region and has a high Mn concentration. The cross-section of the fluoride phosphor particle has a third region which is inside the second region and has a lower Mn concentration, A fluoride phosphor particle comprising the group consisting of the first region, the second region, and the third region, wherein the area of ​​the second region is the largest. General form (1): A ２ M （１－ｎ） F ６ Mn ４＋ ｎ (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, where 0 < n ≤ 0.1.)

2. The fluoride phosphor particle according to claim 1, wherein the proportion of the area of ​​the second region is 50% or more when the sum of the areas of the first region, the second region, and the third region is taken as 100%.

3. The fluoride phosphor particle according to claim 1 or 2, wherein the area ratio of the second region to the third region (second / third) is 10 or more.

4. The mean value Pa of the Mn level in the first region １ This is less than 75% of the average value Pa of the Mn level across the entire cross-section of the fluoride phosphor particles. The mean value Pa of the Mn level in the second region ２ This is greater than or equal to 75% of the average value Pa of the Mn level across the entire cross-section of the fluoride phosphor particles. The average value Pa of the Mn level in the third region ３ The fluoride phosphor particles according to claim 1 or 2, wherein the average value Pa of the Mn level in the third region is less than 75% of the average value Pa of the Mn level over the entire cross-section of the fluoride phosphor particles.

5. The mean value Pa of the Mn level in the third region ３ The average value Pa of the Mn level of the second region for ２ Ratio (Pa ２ / Pa ３ The fluoride phosphor particles according to claim 1 or 2, wherein the ratio is 1.50 or higher.

6. Fluoride phosphor particles according to claim 1 or 2, wherein the Mn content based on ICP emission spectrometry is 0.5% by mass or more and 1.5% by mass or less.

7. 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 The 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.

8. Fluoride phosphor particles according to claim 1 or 2, wherein the external quantum efficiency when irradiated with light of a wavelength of 455 nm is 66.0% or more.

9. A composite comprising fluoride phosphor particles according to claim 1 or 2, and a sealing material for sealing the fluoride phosphor particles.

10. A light-emitting device comprising a light-emitting element that emits excitation light, and a composite according to claim 9 that converts the wavelength of the excitation light.

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