Phosphor, light-emitting device and method for producing a phosphor

Abstract

Fluorescent material, which is described by the general formula: A2MF6 : Mn, where element A is an alkali metal element, and element M is a tetravalent metallic element or several tetravalent metallic elements selected from Si, Ge, Sn, Ti, Zr and Hf, expressing the minimum value of the light absorption rate occurring at wavelengths of 300 nm or more and 350 nm or less being 67% or less, the maximum light absorption rate occurring at wavelengths of 400 nm or more and 500 nm or less being 65% or more, and the Mn content being 0.3 wt% or more and 1.5 wt% or less.

Description

Technical area

[0001] The present invention relates to a phosphor that efficiently emits red light when excited by a blue light, a light-emitting device using this phosphor, and a method for producing this phosphor. State of the art

[0002] In JP 2009 - 528 429 A, a red light emitting phosphor formed by A2[MF6] : Mn 4+ (Element A is, for example, Li, Na, K, Rb, Cs, NH4, and element M is, for example, Ge, Si, Sn, Ti, Zr) and discloses a method for producing it. This production method is a production method in which an A2[MF6] crystal, which will become the matrix of the phosphor, and a K2MnF6 crystal containing Mn, which will become the light-emitting center, are dissolved in hydrofluoric acid and evaporated to dryness.

[0003] From US 2013 / 0 241 396 A1 a white light emitting device is known which comprises a light emitting element having a peak wavelength of 430 to 460 nm and a fluorescent layer on the light emitting element which contains a red fluorescent material and a green-yellow fluorescent material.

[0004] US 2010 / 0 142 189 A1 describes a light source intended for use as a backlight for a color display. The light source comprises a semiconductor light-emitting device for emitting blue, deep blue, and / or ultraviolet light and a combination of phosphors. The phosphors include a green-emitting phosphor and a red-emitting phosphor, for which the rate of change of the emission peak intensity at 100°C compared to that at 25°C is at most 40%, at an excitation wavelength of 400 or 455 nm.

[0005] Furthermore, WO 2015 / 115 195 A1 describes a phosphor having a chemical composition represented by the formula A2MF6:Mn, where A is at least one alkali metal selected from Li, Na, K, Rb and Cs, and comprises at least Na and / or K, and M is at least one tetravalent element selected from Si, Ti, Zr, Hf, Ge and Sn.

[0006] In the article “Micronization of red-emitting K2SiF6:Mn 4+ phosphor by pulsed laser irradiation in liquid“ NAKAMURA, T.; YUAN, Z.; ADACHI, S (Appl. Surf. Sci., Vol. 320, 2014, pp. 514-518) a technique for the micronization of K2SiF6:Mn 4+ -phosphor particles by pulsed laser irradiation in liquid.

[0007] For the provision of a red light-emitting phosphor having an emission peak with a narrow half-width and high light intensity, and a light-emitting device using this phosphor, JP 2013 - 14 715 A discloses that the fluoride phosphor is represented by the general formula K2Ge x Si y F6; Mn 4+ 1-x-y where x and y satisfy the expressions: 0.4<(1-y) / y<5.0 and 0.80<(x+y)<0.99). Summary of the inventionTechnical task

[0008] However, the optical properties of the phosphor of JP 2009 - 528 429 A are insufficient, so that a further improvement of the fluorescence intensity is required for practical application. Consequently, the present invention intends to provide an A2MF6:Mn 4+-phosphor having a high fluorescence intensity, a light-emitting device using this phosphor having a high luminance, and a method for producing the phosphor. Solution to the task

[0009] The present invention is a phosphor expressed by the general formula: Al2MF6:Mn (wherein element A is an alkali metal element, and element M is one or more tetravalent metallic elements selected from Si, Ge, Sn, Ti, Zr, and Hf), wherein the minimum value of the light absorption rate occurring at a wavelength of 300 nm or more and 350 nm or less is 67% or less, the maximum light absorption rate at a wavelength of 400 nm or more and 500 nm or less is 65% or more, and the Mn content is 0.3 mass% or more and 1.5 mass% or less. Preferably, the average grain size of the phosphor is 10 μm or more and 35 μm or less.

[0010] The present invention is a light-emitting device including the above phosphor and a light source for light emission, which is a light-emitting device having a peak wavelength of the light source for light emission of 420 nm or more and 480 nm or less.

[0011] The light-emitting device preferably comprises the above phosphor and a green phosphor having a peak wavelength of 510 nm or more and 550 nm or less when receiving an excitation light of 455 nm as the phosphor. Eu-activated β-SiALON is preferably used as the green phosphor of the light-emitting device.

[0012] The present invention is a phosphor manufacturing method for producing the above phosphor, which comprises a dissolution step in which the starting material is dissolved in hydrofluoric acid, a precipitation step in which the phosphor is precipitated from the solution after the dissolution step, and a rinsing step in which impurities are removed, wherein the aqueous hydrofluoric acid solution obtained in the dissolution step contains the element A, the element M and Mn, and the precipitation is carried out using the precipitation step as a means of evaporating the aqueous hydrofluoric acid solution after the dissolution step.

[0013] The present invention is a phosphor manufacturing method for producing the above phosphor, comprising a dissolution step of dissolving the starting material in hydrofluoric acid, a precipitation step of precipitating the phosphor from the solution after the dissolution step, and a rinsing step of removing impurities. The aqueous hydrofluoric acid solution obtained in the dissolution step contains element A, element M, and Mn, and the precipitation by the precipitation step is carried out as a means for using a poor solvent in the aqueous hydrofluoric acid solution. Preferably, the poor solvent is water.

[0014] The present invention is a phosphor manufacturing method for producing the above phosphor, which comprises a dissolution step in which the starting material is dissolved in hydrofluoric acid, a precipitation step in which the phosphor is precipitated from the solution after the dissolution step, and a rinsing step in which impurities are removed, wherein in the dissolution step, at least two kinds of aqueous hydrofluoric acid solutions containing the element A, the element M and Mn are prepared, and the precipitation by means of the precipitation step is carried out as a means for mixing and reacting the at least two kinds of aqueous hydrofluoric acid solutions with each other. Effects of the invention

[0015] The phosphor of the present invention is a phosphor with high fluorescence intensity that efficiently emits fluorescent light upon excitation light. The light-emitting device of the present invention uses the phosphor, thus resulting in a light-emitting device with high luminance. The method for producing a phosphor of the present invention can produce a phosphor with high fluorescence intensity. Brief explanation of the figures [ Fig. 1] Fig. Figure 1 is a reference figure showing the absorption rate of the phosphor of Example 1 and Comparative Example 4 depending on the excitation wavelength. Description of embodiments

[0016] The present invention is a phosphor expressed by the general formula: A2MF6 : Mn (wherein element A is an alkali metal element, and element M is one or more tetravalent metallic elements selected from Si, Ge, Sn, Ti, Zr, and Hf), wherein the minimum value of the light absorption rate occurring at a wavelength of 300 nm or more and 350 nm or less is 67% or less, the maximum light absorption rate at a wavelength of 400 nm or more and 500 nm or less is 65% or more, and the Mn content is 0.3 mass% or more and 1.5 mass% or less. Element A is an alkali metal element, and from the viewpoint of the crystal structure, it is preferably at least one kind of element selected from Na, K, and Rb.

[0017] The element M is one or more metallic elements selected from Si, Ge, Sn, Ti, Zr, and Hf, with Si, Ge, and Ti being preferred based on their fluorescence properties and chemical stability. The fluorescence properties of the phosphor are influenced by the type of element M. F is hydrofluoric acid, and Mn is manganese. Although Mn can be found with various oxidation numbers, Mn 4+ acts as a substance of the light emission center of the phosphor of the present invention.

[0018] The activation ion of the phosphor is Mn 4+an excitation band in the wavelength range of 300 nm and more and 400 nm and less, and in the wavelength range of 400 nm and more and 500 nm and less. The peak wavelength in the excitation band varies depending on the type of element M, with the peak wavelength of the excitation band on the long wavelength side being 440 nm and more and 480 nm and less.

[0019] The peak wavelength of the excitation band on the long wavelength side coincides with the light emission wavelength of a blue LED used as an excitation source for a white LED. If the light absorption rate in this wavelength range is less than 65%, sufficient luminance cannot be achieved in the light-emitting device using this phosphor. Therefore, at a wavelength of 400 nm or more and 500 nm or less, a maximum light absorption rate of 65% or more is preferably achieved, more preferably 66% or more, even more preferably 68% or more, and further preferably 78% or more can be achieved.

[0020] In the phosphor of the present invention, the minimum value of the light absorption rate occurring at a wavelength of 300 nm or more and 350 nm or less was determined to be 67% or less for the following reason.

[0021] The reason is that the light absorption rate of UV light in the wavelength range of 300 nm or more and 350 nm or less is negatively correlated with the internal quantum efficiency of the phosphor (the efficiency with which absorbed excitation photons are converted into fluorescence photons).

[0022] Causes for the light absorption are, apart from the excitation of the Mn 4+ Impurities and crystal defects. Such crystal defects capture the Mn 4+ excited electrons and suppress light emission. The inventors of the present invention discovered the overlap of the absorption of the UV light range resulting from crystal defects and the absorption band of Mn 4+ near a wavelength of 350 nm.

[0023] The minimum value of the light absorption rate is at a wavelength of 300 nm or more and 350 nm or less, and the lower the minimum value, the higher the internal quantum efficiency of the phosphor, so the "minimum value of the light absorption rate occurring at a wavelength of 300 nm or more and 350 nm or less was determined to be 67% or less." Preferably, the minimum value can be determined to be 66% or less, and more preferably, 56% or less.

[0024] In the phosphor of the present invention, the maximum light absorption rate at a wavelength of 400 nm or more and 500 nm or less was determined to be 65% or more in order to achieve sufficient luminance with the light-emitting device using the phosphor of the present invention.

[0025] The Mn content of the phosphor of the present invention is preferably 0.3 mass% or more and 1.5 mass% or less. This is because if the Mn content is too low, sufficient fluorescence emission tends to be unobtainable. However, if it is too high, fluorescence emission tends to decrease due to the increase in crystal defects and concentration quenching.

[0026] The average grain size of the phosphor of the present invention is preferably 10 µm or more and 35 µm or less. The average grain size is the volume mean diameter determined from the grain size distribution curve measured by laser diffraction scattering.

[0027] If the mean grain size is too small, there is a tendency for the fluorescence intensity to decrease due to the extensive decrease in the light absorption rate, while if the mean grain size is too large, the amount of phosphor added to achieve a certain color increases, so that there is a tendency for a donor to be blocked during assembly.

[0028] The present invention is a light-emitting device including the above phosphor and a light source for light emission, which is a light-emitting device having a peak wavelength of the light source for light emission of 420 nm or more and 480 nm or less. The peak wavelength of the light source for light emission was determined to be 420 nm or more and 480 nm or less in order to, on the one hand, 4+as a light emission center in the phosphor and on the other hand for use as blue light of the light-emitting device.

[0029] The phosphor of the present invention exhibits high fluorescence intensity due to the above structure. Specifically, in the present invention, high fluorescence intensity means an internal quantum efficiency of 70% or more and an external quantum efficiency of 57% or more.

[0030] The light-emitting device preferably comprises, as the phosphor, the above phosphor and a green phosphor having a peak wavelength of 510 nm or more and 550 nm or less when receiving an excitation light of 455 nm. The light-emitting device can emit white light by using the blue light-emitting light source, the red phosphor, and the green phosphor. Furthermore, light emission in a different color range is also possible by varying the mixing ratio of the phosphors. If an Eu-activated β-SiAlON phosphor with a narrow fluorescence spectrum at half maximum is used as the green phosphor, a liquid crystal backlight light source with a wide color gamut is achieved.

[0031] As a method for producing the phosphor of the present invention, there are the following methods: 1) Solvent evaporation method: A method in which the solvent is evaporated after the element that becomes the starting material of the phosphor is dissolved in a hydrofluoric acid solvent. 2) Precipitation process after addition of a poor solvent: Process in which a poor solvent is added and the phosphor is precipitated. 3) Mixture reaction precipitation method: A method in which at least two kinds of hydrofluoric acid solutions in which the element which will become the starting material of the phosphor has been dissolved are mixed and reaction precipitation of the phosphor takes place.

[0032] In all manufacturing processes, it is important that during the crystal growth the formation of crystal defects that affect the Mn 4+ excited electrodes and suppress light emission is as small as possible. Examples

[0033] The present invention will be explained in detail based on examples and comparative examples. Example 1

[0034] The phosphor of Example 1 is a phosphor represented by the general formula: A2MF6:Mn, which is a phosphor containing K (potassium) as element A, Si (silicon) as element M, a minimum light absorption rate occurring at a wavelength of 300 nm or more and 350 nm or less of 55.5%, a maximum light absorption rate at a wavelength of 400 nm or more and 500 nm or less of 78.1%, a Mn content of 0.75 mass%, and an average grain size of 29.8 μm. These characteristics and the effects of the invention mentioned later are shown in Table 1. [Table 1] Starting material fluorescent Evaluation K2SiF6 additional amount (9) K2MnF6 additional amount (9) Light absorption rate (%) Mn content (mass%) average grain size (µm) Excitation wavelength: 455 nm 300-350 nm minimum value 400-500 nm maximum value internal quantum yield (%) external quantum yield (%) Example 1 30 5 55,5 78,1 0,75 29,8 82,5 64,4 Example 2 30 2,5 52,3 68,8 0,41 28,7 86,8 57,7 Example 3 30 7,5 65,2 82,5 0,92 30,5 76,8 63,4 Example 4 50 8,3 63,1 80,5 0,71 31,8 78,2 63,0 Comparison example 1 30 10 72,5 87,2 1,62 30,8 62,4 54,4 Comparison example 2 30 1 49,8 54,2 0,21 27,7 84,4 45,7 Comparison example 3 60 8,3 69,3 73,2 0,65 30,3 76,5 56,0

[0035] The measurement method of the parameters and the manufacturing process of the phosphor of Example 1 are explained.

[0036] The excitation wavelength dependence of the light absorption rate of the phosphor of Example 1 was measured by the following method at normal temperature.

[0037] A standard reflector with a reflectance of 99% (Spectralon, manufactured by Labsphere) was installed in the side aperture (φ 10 mm) of an integrating sphere (φ 60 mm). Monochromatic light of a specific wavelength, dispersed into its spectrum by a Xe lamp as the light-emitting light source, was introduced into the integrating sphere via optical fibers as excitation light. The reflected light spectrum of the standard reflector was measured using a spectrophotometer (MCPD-7000, manufactured by Otsuka Electronics Co., Ltd.) in a wavelength range of 220 to 800 nm. The excitation light was irradiated in a range of 300 nm and above and 700 nm and below at a distance of 5 nm, and the spectrum of the reflected light relative to the respective excitation light was measured.

[0038] The phosphor was filled into a concave cell in such a way that the surface was smoothed, and this was inserted into the opening of the integrating sphere. As with the standard reflector, it was irradiated with a monochromatic light in a range of 300 nm and more and 700 nm and less at a distance of 5 nm and the spectrum was measured using the excitation light with the respective wavelength.

[0039] The spectrum obtained was the reflection spectrum of the excitation light and the fluorescence spectrum near red light.

[0040] In the resulting spectra, the light absorption rate of the phosphor was calculated for the respective excitation wavelength by calculating the photon number of the reflected light of the excitation in the range of a set excitation wavelength from -5 nm to +10 nm and dividing the photon number of the reflected light of the excitation for the phosphor by the value of the standard reflector. Fig. Figure 1 shows the light absorption rate of the phosphor of Example 1 measured in this way plotted against the excitation wavelength.

[0041] The light absorption rate showed by the excitation with Mn 4+a maximum light absorption rate at an excitation wavelength of 350 nm and 450 nm, wherein the minimum value of the light absorption rate occurring in the range of a wavelength of 300 nm or more and 350 nm or less was 55.5% and the maximum light absorption rate in the range of a wavelength of 400 nm or more and 500 nm or less was 78.1%.

[0042] The Mn content contained in the phosphor of Example 1 was 0.75 mass% as a result of measurement by ICP (inductively coupled plasma) optical emission spectrometry.

[0043] The average grain size of the phosphor of Example 1 was measured using a laser diffraction grain size distribution measuring device (LC 13320, manufactured by Beckman Coulter), and the average grain size (50 vol% diameter (D50)) was determined from the resulting cumulative grain size distribution curve. The average grain size of the phosphor of Example 1 was 29.8 µm. Ethanol was used as the measurement solvent in the measuring device.

[0044] The internal quantum yield and the external quantum yield at an excitation wavelength of 455 nm were determined using the following procedure:

[0045] In the spectrum to the standard reflector, the photon number of the excitation light (Qex) was calculated using the spectrum of a wavelength range of 450 nm or more and 465 nm or less.

[0046] Based on the spectrum of the phosphor, the photon number of the reflected light of the excitation (Qref) and the photon number of the fluorescence (Qem) were calculated.

[0047] The photon count of the reflected excitation light was calculated in the same wavelength range as the excitation light, and the photon count of the fluorescence was calculated in a range from 465 to 800 nm. Based on the obtained photon counts, the external quantum yield (= Qem / Qex × 100) and the internal quantum yield (= Qem / (Qex - Qref) × 100) were determined.

[0048] The internal quantum efficiency and the external quantum efficiency of the phosphor of Example 1 excited at a wavelength of 455 nm were 82.5% and 64.4%, respectively.

[0049] The manufacturing process of the phosphor of Example 1 is explained.

[0050] The phosphor of Example 1 is a phosphor prepared by the above precipitation method after adding a poor solvent. The precipitation method after adding the poor solvent included a dissolution step in which the starting materials were dissolved in hydrofluoric acid, a precipitation step in which the phosphor was precipitated from the solution after the dissolution step, and a rinsing step to remove impurities.

[0051] The starting materials for the phosphor were K2SiF6 (manufactured by Morita Chemical Industries Co., Ltd., purity at least 98%) and K2MnF6. Both were powdered. The manufacturing process for K2MnF6 is explained below. <Herstellungsschritt von K2MnF6>

[0052] In a 1-liter Teflon® beaker, 800 ml of hydrofluoric acid with a density of 40 mass% was added, and 260 g of powdered KHF2 (manufactured by Wako Pure Chemical Industries, Ltd., guaranteed reagent) and 12 g of potassium permanganate powder (manufactured by Wako Pure Chemical Industries, Ltd., high-purity reagent) were dissolved.

[0053] While stirring the hydrofluoric acid reaction solution with a magnetic stirring bar, 8 ml of a 30% hydrogen peroxide solution (manufactured by Wako Pure Chemical Industries, Ltd., guaranteed reagent) was gradually added.

[0054] When a certain amount of hydrogen peroxide solution was instilled, yellow particles began to settle, and the color of the reaction solution began to change from violet. After a certain amount of hydrogen peroxide solution was instilled and stirring continued for a while, stirring was stopped, and the precipitated particles began to settle. The entire above reaction was carried out at normal temperature. <Spülungsschritt von K2MnF6>

[0055] After deposition, the supernatant liquid was removed, methanol was added, the solution was stirred and allowed to stand, the supernatant liquid was removed and methanol was added again, and this process was repeated until the solution was neutralized.

[0056] Subsequently, the precipitated particles were collected by filtration, further drying was carried out and the methanol was completely removed by evaporation, obtaining 19 g of powdered K2MnF6. <Herstellungsschritt des Leuchtstoffs>

[0057] In a 3,000-mL Teflon® beaker, 1,000 mL of hydrofluoric acid with a density of 55 mass% were added, 30 g of powdered K2SiF6 (manufactured by Morita Chemical Industries Co., Ltd., purity at least 98%) and 5 g of the above K2MnF6 were added and dissolved with sufficient stirring.

[0058] While stirring the aqueous hydrofluoric acid solution, 1,500 ml of distilled water was poured into the reaction solution via a beaker over approximately 1 minute. Visual inspection revealed the formation of a yellow powder in the reaction solution due to the use of distilled water. The entire preparation step was carried out at ambient temperature. <Spülungsschritt des Leuchtstoffs>

[0059] After the distilled water was completely added, the solution was stirred for a further 20 minutes and then allowed to stand still, allowing the solid components to settle. After settling was observed, the supernatant liquid was removed, followed by rinsing with 20% by mass hydrofluoric acid and methanol. The solid components were separated and collected by filtration. The methanol residue was then removed by evaporation, and a yellow phosphor powder was obtained.

[0060] For the phosphor of Example 1, the X-ray diffraction pattern was measured using an X-ray diffraction device (Ultima IV, manufactured by Rigaku Corporation). It was found that the phosphor of Example 1 consists of K2SiF6 crystals and is monophase. [Examples 2 to 4 and Comparative Examples 1 to 3]

[0061] Examples 2 to 4 and Comparative Examples 1 to 3 are phosphors prepared by the same process as Example 1, except that the addition amount of K2SiF6 and K2MnF6 shown in the starting material column of Table 1 was changed.

[0062] In the phosphor of Comparative Example 1, the minimum value of the light absorption rate occurring at a wavelength of 300 nm or more and 350 nm or less was greater than 67%, and the Mn content was more than 1.5 mass%, so that the internal quantum efficiency and the external quantum efficiency did not meet the success value.

[0063] In the phosphor of Comparative Example 2, the minimum value of the light absorption rate occurring at a wavelength of 400 nm or more and 500 nm or less was less than 65%, and the Mn content was more than 1.5 mass%, so the external quantum efficiency did not meet the success value.

[0064] In the phosphor of Comparative Example 3, the minimum value of the light absorption rate occurring at a wavelength of 300 nm or more and 350 nm or less was greater than 67%, so the external quantum efficiency did not meet the success value. [Comparison example 4]

[0065] The phosphor of Comparative Example 4, which is not shown in Table 1, is a phosphor produced by a different production method than the above examples, namely, the mixture reaction precipitation method.

[0066] A hydrofluoric acid solution X was prepared by placing 250 ml of hydrofluoric acid with a density of 55 mass% into a 500 ml Teflon® beaker at normal temperature, into which 12 g of SiO2 powder (manufactured by Japan Pure Chemical Co., Ltd., purity 99.9%) and 4 g of K2MnF6 powder (the K2MnF6 prepared in Example 1) were added and dissolved.

[0067] On the other hand, a hydrofluoric acid solution Y was prepared by dissolving 46.9 g of KHF2 powder (manufactured by Wako Pure Chemical Industries, Ltd., guaranteed reagent) in 100 ml of hydrofluoric acid with a density of 55 mass% using a 300 ml Teflon® beaker.

[0068] Hydrofluoric acid solution Y was added to hydrofluoric acid solution X, which was stirred using a stir bar. The addition of the Y solution precipitated the phosphor in the X solution. After adding all of the Y solution, the solution was stirred for 20 minutes and then allowed to stand still so that the solid components settled.

[0069] After the settling was observed, the supernatant liquid was removed, then rinsed with 20 mass% hydrofluoric acid and methanol, and the solid components were separated and collected by filtration, and then yellow phosphor powder was obtained by a drying process.

[0070] The phosphor of Comparative Example 4 was K2SiF6 crystals and was monophase. The minimum light absorption rate, which occurred in the wavelength range from 300 nm to 350 nm, was 67.3%, and the maximum light absorption rate was 81.5% in the wavelength range from 400 to 500 nm. The Mn content was 0.68 mass%, and the average grain size was 30.2 µm.

[0071] In Fig. Figure 1 shows the absorption rate of Comparative Example 4 as a function of the excitation wavelength.

[0072] The internal quantum efficiency and external quantum efficiency of the phosphor of Comparative Example 4 were 68.9% and 56.1%, respectively. Although the phosphor of Comparative Example 4 is similar to the phosphor of Example 1 in terms of Mn content and grain size distribution, it was reflected in Fig.1, the different dependence of the light absorption rate on the excitation wavelength is reflected in a low value of both the internal quantum yield and the external quantum yield. [Example 5]

[0073] The phosphor of Example 5 is a phosphor represented by the general formula: A2MF6:Mn, which is a phosphor having K (potassium) as element A, Ge (germanium) as element M, a minimum light absorption rate occurring at a wavelength of 300 nm or more and 350 nm or less of 46.0%, a maximum light absorption rate at a wavelength of 400 nm or more and 500 nm or less of 79.6%, a Mn content of 0.61 mass%, and an average grain size of 38.4 μm. These characteristics and the effects of the invention mentioned later are shown in Table 2. [Table 2] fluorescent Evaluation KHF2 additional procedure X-ray diffraction (crystal phase) Light absorption rate (%) Mn content (mass%) average grain size (µm) Excitation wavelength: 455 nm 300-350 nm minimum value 400-500 nm maximum value internal quantum yield (%) external quantum yield (%) Example 5 solvent K2GeF6 46,0 79,6 0,62 38,4 84,3 66,2 Comparison example 5 powder K2GeF6 67,5 58,8 0,58 40,2 59,2 33,7

[0074] The manufacturing process of the phosphor of Example 5 is explained.

[0075] The manufacturing method of the phosphor of Example 5 is the mixture reaction precipitation method.

[0076] A hydrofluoric acid solution was prepared by placing 250 ml of hydrofluoric acid with a density of 48 mass% into a 500 ml Teflon® beaker at normal temperature, into which 20.9 g of GeO2 powder (manufactured by Japan Pure Chemical Co., Ltd., purity 99.99%) and 3 g of K2MnF6 powder (the K2MnF6 prepared in Example 1) were added and dissolved.

[0077] In Example 5, a solution was added to this solution in which 46.9 g of KHF2 powder were dissolved in 100 ml of hydrofluoric acid with a density of 48 mass%.

[0078] The phosphor was precipitated by the hydrofluoric acid solution of KHF2. After the hydrofluoric acid solution of KHF2 was completely added, it was stirred for 20 minutes and then allowed to stand still, allowing the solid components to settle. Once the settling was observed, the supernatant was discarded.

[0079] Until the sediment became a strong yellow color, repeated rinsing with 20 mass% hydrofluoric acid and also rinsing with methanol were carried out, the solid components were separated and collected by filtration, and then methanol residues were removed by a drying process by evaporation, and the phosphor of Example 5 was obtained.

[0080] The internal quantum yield and the external quantum yield of Example 5 each corresponded to the success value.

[0081] The phosphor of Comparative Example 5 is a phosphor in which, in the manufacturing process, the "solution in which 46.9 g of KHF2 powder was dissolved in 100 ml of hydrofluoric acid having a density of 48 mass%" in Example 5 was changed to "46.9 g of KHF2 powder", and the characteristics and evaluation are as shown in Table 2.

[0082] In Comparative Example 5, since the minimum value of the light absorption rate observed near 300 nm was extremely high, the grain size was small, and the light absorption rate near 450 nm was low, the internal quantum yield and external quantum yield were low compared to Example 5. Changing the addition method of KHF2 from a solution to a powder reduced crystal growth.

[0083] Examples 6 and 7, which are not shown in the table, are the phosphor of Example 1 with an average grain size of 8 µm and 40 µm, respectively. Although the internal quantum efficiency and external quantum efficiency were lower than those of Example 1, they were still equivalent to the successful result.

[0084] Although not shown as an example, a phosphor equivalent to that in Example 1 could also be obtained by the solvent evaporation process by carrying out a synthesis in which the formation of crystal defects was suppressed as much as possible.

[0085] Example 8 is a light-emitting device comprising the phosphor of Example 1 and an LED as the light source for light emission. This light-emitting device has an LED peak wavelength of 455 nm. Specifically, the light-emitting device is a lighting device. The light-emitting device of Example 8 used the phosphor of Example 1, thus resulting in a light-emitting device with high luminous intensity.

[0086] Example 9 is a light-emitting device in which the phosphor of Example 1 and a green phosphor with a peak wavelength of 528 nm when receiving an excitation light of 455 nm were chosen as the phosphor of Example 8. Specifically, the green phosphor is (Ba, Sr)2SiO4:Eu. A green phosphor was used in this light-emitting device, resulting in a white-light-emitting light-emitting device.

[0087] Example 9 used the phosphor of Example 1, so it was a light-emitting device with a high luminous intensity.

[0088] The tenth example is a light-emitting device in which (Ba, Sr)2SiO4 : Eu of Example 9 was changed to Eu-activated β-SiALON.

[0089] Example 10 was a light-emitting device having better high temperature stability and moisture resistance than Example 9.

Claims

[1] Phosphor represented by the general formula: A2MF6 : Mn, wherein the element A is an alkali metal element, and the element M is one or more tetravalent metallic elements selected from Si, Ge, Sn, Ti, Zr and Hf, wherein the minimum value of the light absorption rate occurring at a wavelength of 300 nm or more and 350 nm or less is 67% or less, the maximum light absorption rate at a wavelength of 400 nm or more and 500 nm or less is 65% or more, and the Mn content is 0.3 mass% or more and 1.5 mass% or less. [2] The phosphor according to claim 1, wherein the average grain size is 10 µm or more and 35 µm or less. [3] A light-emitting device including the phosphor according to claim 1 or claim 2 and a light source for light emission, which is a light-emitting device having a peak wavelength of the light source for light emission of 420 nm or more and 480 nm or less. [4] A light-emitting device according to claim 3, comprising as a phosphor the phosphor according to claim 1 or claim 2 and a green phosphor having a peak wavelength of 510 nm or more and 550 nm or less when receiving an excitation light of 455 nm. [5] The light-emitting device according to claim 4, wherein the green phosphor is Eu-activated β-SiALON. [6] A manufacturing method for a phosphor for producing the phosphor according to claim 1 or 2, comprising a dissolution step in which the starting material is dissolved in hydrofluoric acid, a precipitation step in which the phosphor is precipitated from the solution after the dissolution step, and a rinsing step in which impurities are removed, wherein the aqueous hydrofluoric acid solution obtained in the dissolution step contains an element A, an element M and Mn, and the precipitation was carried out using the precipitation step as an evaporation means of the aqueous hydrofluoric acid solution after the dissolution step. [7] A manufacturing method for a phosphor for producing the phosphor according to claim 1 or 2, which comprises a dissolution step in which the starting material is dissolved in hydrofluoric acid, a precipitation step in which the phosphor is precipitated from the solution after the dissolution step, and a rinsing step in which impurities are removed, wherein the aqueous hydrofluoric acid solution obtained in the dissolution step contains the element A, the element M and Mn, and the precipitation by means of the precipitation step is carried out as a means for using a poor solvent in the aqueous hydrofluoric acid solution. [8] A manufacturing method for a phosphor according to claim 7, wherein the poor solvent is water. [9] A manufacturing method for a phosphor for producing the phosphor according to claim 1 or 2, comprising a dissolving step in which the starting material is dissolved in hydrofluoric acid, a precipitation step in which the phosphor is precipitated from the solution after the dissolving step, and a rinsing step in which impurities are removed, wherein in the dissolving step, at least two kinds of aqueous hydrofluoric acid solutions containing the element A, the element M and Mn are prepared, and precipitation by means of the precipitation step is carried out as a means for mixing and reacting the at least two kinds of aqueous hydrofluoric acid solutions with each other.

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