JP6614072B2 - Mn-activated bifluoride phosphor and method for producing the same - Google Patents

Description

The present invention relates to a formula K ₂ MF ₆ : Mn (wherein M is one, two or more tetravalent elements selected from Si, Ti, Zr, Hf, Ge and Sn, which are useful as red phosphors for blue LEDs) In this case, the present invention relates to a Mn-activated double fluoride red phosphor (double fluoride phosphor) represented by the formula (1) and a method for producing the same.

For the purpose of improving the color rendering of white LEDs (Light Emitting Diodes) or improving the color reproducibility when white LEDs are used as backlights for liquid crystal displays, they are excited by light equivalent to LEDs from near-ultraviolet to blue. Phosphors that emit light are needed and research is ongoing. Among them, JP 2009-528429 A (Patent Document 1) discloses a compound F ₂ represented by a formula such as A ₂ MF ₆ (A is Na, K, Rb, etc., M is Si, Ge, Ti, etc.). It is described that a compound obtained by adding Mn to a compound (double fluoride phosphor) is useful.

  Regarding the method for producing the phosphor, Patent Document 1 discloses a method in which a hydrofluoric acid solution in which all constituent elements are dissolved or dispersed is evaporated and concentrated. As another manufacturing method, in US Pat. No. 3,576,756 (Patent Document 2), after mixing a hydrofluoric acid solution in which each constituent element is dissolved, acetone, which is a water-soluble organic solvent, is added to lower the solubility. The method of making it precipitate by making it disclose is disclosed. Furthermore, Japanese Patent No. 4582259 (Patent Document 3) and Japanese Patent Application Laid-Open No. 2012-224536 (Patent Document 4) disclose a solution containing hydrofluoric acid in which the element M and the element A in the above formulas are separate. A method for precipitating a phosphor by dissolving a solution in which Mn has been added and mixing again is disclosed.

The manufacturing process of the known Mn-added A ₂ MF ₆ double fluoride phosphor described above requires the use of a high concentration of hydrofluoric acid in a considerably large amount relative to the amount of the phosphor obtained. is there. The corrosiveness and toxicity to the human body of hydrofluoric acid are obstacles to the implementation of this phosphor manufacturing process, particularly to enlargement.

  To solve the problem, one of the inventors of the present invention, when manufacturing a red phosphor that is Mn-activated bifluoride, is not essentially wet, but by mixing and heating the raw material powder. It is found that the main part of the process for producing the phosphor can be carried out without using hydrofluoric acid by causing the diffusion transfer of the substance to produce the target double fluoride phosphor. It describes in international publication 2015/115189 (patent document 5).

On the other hand, phosphors such as K ₂ SiF ₆ : Mn, which have been disclosed so far, such as the above-mentioned documents, are required in order to obtain a desired red color, for example, blue LED light, green or yellow phosphor There is a problem that the amount of the red phosphor itself necessary for obtaining white light as a whole in combination with the above-mentioned light is larger than those of other emission color phosphors and other types of red phosphors.
In addition, the following literature is mentioned as a prior art document relevant to this invention.

Special table 2009-528429 gazette US Pat. No. 3,576,756 Japanese Patent No. 4582259 JP 2012-224536 A International Publication No. 2015/115189

H. Bode, H.M. Jenssen, F.M. Bandte, Angew. Chem. 65, 304, (1953) E. Huss, W.H. Klemm, Z .; Anorg, Allg. Chem. 262, 25 pages, (1950) B. Cox, A.M. G. Sharpe, J. et al. Chem. Soc. , 1798 pages, (1954) Published by Maruzen Co., Ltd., Chemical Society of Japan, New Experimental Chemistry Course 8 “Synthesis of Inorganic Compounds III”, published in 1977, page 1166 R. Hoppe, W.H. Liebe, W.M. Daehne, Z .; Anorg, Allg. Chem. 307, 276, (1961)

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a manganese-activated double fluoride red phosphor and a method for producing the same, which requires a smaller amount necessary to obtain the target red color than in the past. And

The inventors of the present invention have problems with Mn-activated double fluoride red phosphors such as K ₂ SiF ₆ : Mn that have been produced in the past for some reason when the Mn content is relatively low or Mn is high. Focusing on the fact that the conversion efficiency from blue to red is decreasing, and as a result of intensive studies, a multifluoride phosphor with a high Mn content and a high conversion efficiency (internal quantum efficiency) from blue to red As a result, the present inventors have found a condition that can be manufactured, and have made the present invention.

That is, this invention provides the following Mn activation double fluoride fluorescent substance and its manufacturing method.
[1]
Following formula (1)
K ₂ MF ₆ : Mn (1)
(In the formula, M is one or two or more tetravalent elements selected from Si, Ti, Zr, Hf, Ge, and Sn, and necessarily includes Si.)
A method for producing a Mn-activated double fluoride phosphor, comprising mixing a solid of K ₂ MnF ₆ with a red phosphor, which is a Mn-activated double fluoride represented by the formula, and heating at 100 ° C. to 500 ° C. .
[2]
Together with the above K ₂ MnF ₆ , the following formula (2)
AF / nHF (2)
(In the formula, A is one or two or more alkali metals or ammonium selected from Li, Na, K, Rb, and NH ₄ , and must include K, and n is a number of 0.7 or more and 4 or less. .)
The method for producing a Mn-activated bifluoride phosphor according to [1], wherein a hydrogen fluoride salt represented by the formula:
[3]
[1] or [2], wherein the reaction mixture obtained by heating is washed with an inorganic acid solution or a fluoride salt solution to remove unnecessary components, followed by solid-liquid separation and drying of the solid content. The manufacturing method of Mn activation double fluoride fluorescent substance of description .
[4]
A red phosphor which is a Mn-activated bifluoride represented by the above formula (1), which is represented by the following formula (3)
Mn / (M + Mn) (3)
The ratio of the number of moles or the number of atoms represented by the formula is 0.1 or more and 0.25 or less, the internal quantum efficiency of fluorescence by excitation light of 450 nm is 0.842 or more , and the absorptance is 0.72 or more. A featured Mn-activated double fluoride phosphor.

  According to the present invention, it is possible to obtain a Mn-activated bifluoride phosphor that requires less amount to obtain red light than conventional ones.

It is a schematic sectional drawing which shows an example of the reaction apparatus used for implementation of this invention. It is the fluorescence emission spectrum and fluorescence excitation spectrum of the product obtained in Example 1. It is a schematic sectional drawing of experimental LED used for the evaluation experiment in an Example. It is a light spectrum of LED1 in evaluation experiment in an Example. It is a light spectrum of LED2 under evaluation experiment in an example. It is a figure which shows the chromaticity coordinate of each LED in the evaluation experiment in an Example.

Below, the manufacturing method of the double fluoride fluorescent substance concerning this invention is demonstrated.
The phosphor production method according to the present invention comprises the following formula (1):
K ₂ MF ₆ : Mn (1)
(In the formula, M is one or two or more tetravalent elements selected from Si, Ti, Zr, Hf, Ge, and Sn, and necessarily includes Si.)
A solid of K ₂ MnF ₆ is mixed with a red phosphor, which is a Mn-activated bifluoride represented by the formula, preferably a solid of K ₂ MnF ₆ and the following formula (2):
AF / nHF (2)
(In the formula, A is one or two or more alkali metals or ammonium selected from Li, Na, K, Rb, and NH ₄ , and must include K, and n is a number of 0.7 or more and 4 or less. .)
Is mixed with a solid and heated at 100 ° C. or more and 500 ° C. or less.

  The phosphor of the formula (1) used as a raw material here is not particularly limited, but considering that there is an aim to increase the Mn content of the phosphor as a product and to make the distribution uniform, Mn has a capacity to M + Mn. The ratio [Mn / (M + Mn)] is preferably 0.01 (molar ratio) or more. More preferably, it is 0.02 or more (molar ratio). Production of the raw material phosphor will be described later by way of an actual example, but can be performed by any method such as a wet method described in Patent Document 3 or 4 or a dry method described in Patent Document 5.

K ₂ MnF ₆ used in the production method of the phosphor of the present invention is a known method, that is, (A) H. Bode, H.M. Jenssen, F.M. Bandte, Angew. Chem. 65, 304, (1953) (Non-Patent Document 1), a method of reducing potassium permanganate with hydrogen peroxide in the presence of potassium fluoride, (B) E. Huss, W.H. Klemm, Z .; Anorg, Allg. Chem. 262, 25, (1950) (non-patent document 2), a method of heating a mixture of manganese and anhydrous alkali metal chloride in a fluorine gas stream, (C) B. Cox, A.M. G. Sharpe, J. et al. Chem. Soc. , 1798 pages, (1954) (Non-Patent Document 3) and published by Maruzen Co., Ltd., edited by The Chemical Society of Japan, New Experimental Chemistry Course 8 “Synthesis of Inorganic Compounds III”, published in 1977, Non-Patent Document 4 It is possible to use one prepared by any of the methods described in 1), which is synthesized by an electrolytic reaction of a liquid containing manganese fluoride.

The mixing ratio of the raw material phosphor and K ₂ MnF ₆ is 0.06 to M2 in terms of the number of moles, including that supplied with Mn from the phosphor and that added with K ₂ MnF _6. The ratio is 0.3 mol, preferably 0.1 to 0.25 mol. Since the ratio of Mn to M + Mn in the product phosphor tends to be smaller than the charged amount by the reaction and the subsequent treatment described later, the above values are preferable in consideration thereof. If the amount is less than 0.06 mol, the activator Mn in the product phosphor is insufficient, and blue light absorption is weak, and as a result, there is a possibility that red light cannot be obtained sufficiently. Even if the amount exceeds 0.3 mol, the light emission characteristics may deteriorate.
To mix these ingredients, put both ingredients in a polyethylene bag, shake or rotate, put it in a container with a lid made of polyethylene, put it on a rocking mixer, tumbler mixer, etc. Arbitrary methods can be used.

Furthermore, reaction can be accelerated | stimulated by mixing and heating the hydrogen fluoride salt represented by said Formula (2) with solid to said mixture. As these hydrogen fluoride salts, commercially available products such as ammonium hydrogen fluoride (NH ₄ HF ₂ ), sodium hydrogen fluoride (NaHF ₂ ), potassium hydrogen fluoride (KHF ₂ ), and KF · 2HF may be used. it can.

The addition amount of these hydrogen fluoride salts is preferably 0 to 2.5 mol of A such as an alkali metal with respect to 1 mol of the main component metal M. More preferably, it is 0.1-2.0 mol. Even if the amount of the hydrogen fluoride salt is increased beyond 2.5 mol, there is no advantage in the production of the phosphor, and there is a possibility that the product becomes a lump and is difficult to be loosened.
Although the method of mixing the hydrogen fluoride salt is not limited, it may generate heat during mixing. Therefore, it is desirable to avoid mixing with strong force and to mix in a short time.

The mixing of the hydrogen fluoride salt may be performed simultaneously when mixing the raw phosphor and K ₂ MnF ₆ but, considering the above points, the pre-feed phosphor and K ₂ MnF ₆ It is preferable to mix the hydrofluoric acid salt with the mixed material later.

  As a reaction accelerator, it is also effective to add alkali metal nitrate, sulfate, hydrogen sulfate, and fluoride together with hydrogen fluoride in addition to hydrogen fluoride. The alkali metal is preferably one or more alkali metals selected from Li, Na, K and Rb, and more preferably contains K. The addition amount in this case is preferably in a range not exceeding the hydrogen fluoride salt in terms of moles.

The raw materials mixed as described above are heated. The heating temperature is 100 to 500 ° C, preferably 150 to 450 ° C, more preferably 170 to 400 ° C. The atmosphere during heating can be any of air, nitrogen gas, argon gas, vacuum, etc., but the reducing atmosphere containing hydrogen gas may reduce the light emission characteristics due to the reduction of manganese. It is not preferable.
Either a mixed raw material is put into a sealed container and the whole container is put into a dryer, an oven, or the like, or a method of directly heating with a heater from the outside using a container having a gas outlet is applicable. When using an airtight container, it is preferable to use the one in which the part in contact with the reactant is made of a fluororesin. Not only this but the container made from a fluororesin can be used suitably when heating temperature is 270 degrees C or less. When the heating temperature is higher than this, it is preferable to use a ceramic container. The ceramic in this case is preferably alumina, magnesia or magnesium aluminum spinel.

  More specifically, as an example of a reaction vessel, a double vessel 1 in which an inner layer 3 made of polytetrafluoroethylene is formed on the inner wall of a stainless steel vessel body 2 shown in FIG. 1 is used, and a powder mixture 10 is heated therein. It is preferable to react. In addition, as a material of the cover body 4, it is preferable to use stainless steel.

  The reaction product obtained as described above may contain unreacted hexafluoromanganate in addition to the desired double fluoride phosphor, and hydrogen fluoride salt also remains. . These can be removed by washing.

For washing, an inorganic acid solution such as hydrochloric acid, nitric acid, or hydrofluoric acid, or a fluoride salt solution such as ammonium fluoride or potassium fluoride can be used. A hydrofluoric acid or ammonium fluoride solution is more preferable. In order to suppress the elution of the phosphor component, a water-soluble organic solvent such as ethanol or acetone can be added. It is also effective to dissolve the raw material K ₂ MF ₆ in the cleaning solution. After washing, the solid content is dried by a conventional method to obtain a Mn activated double fluoride phosphor.

Next, the double fluoride phosphor according to the present invention will be described.
The phosphor according to the present invention has the following formula (1):
K ₂ MF ₆ : Mn (1)
(In the formula, M is one or two or more tetravalent elements selected from Si, Ti, Zr, Hf, Ge, and Sn, and necessarily includes Si.)
A red phosphor that is a Mn-activated bifluoride represented by the following formula (3)
Mn / (M + Mn) (3)
(In the formula, M is the same as M in the formula (1)).
The ratio of the number of moles or the number of atoms represented by the formula is 0.06 or more and 0.25 or less, and the internal quantum efficiency of fluorescence by 450 nm excitation light is 0.75 or more.

The ratio of Mn to M + Mn represented by the above formula (3) is calculated from the result of analyzing M elements such as Mn and Si by subjecting a solution prepared by dissolving the entire amount of phosphor in diluted hydrochloric acid to ICP emission analysis. Is what you want. If the ratio of Mn to M + Mn is less than 0.06, blue light is weakly absorbed, and as a result, red light cannot be obtained sufficiently. Moreover, even if it is larger than 0.25, there is no advantage, and there is a possibility that the internal quantum efficiency may be lowered. The value of the formula (3) is preferably 0.09 or more, particularly 0.1 or more and 0.2 or less.
Of the elements represented by M, the Si ratio is preferably 60% or more in terms of moles or atoms. More preferably, it is 80% or more. Other than Si, Ti, Zr, Hf, Ge, and Sn may be substantially not included.

  The internal quantum efficiency of the phosphor of the present invention is preferably 0.75 or more when measured with respect to 450 nm excitation light. When the internal quantum efficiency is less than 0.75, even if blue light is absorbed, the ratio of conversion to red light is small, and the intended red color cannot be obtained. Preferably an internal quantum efficiency of 0.80 or more is required. The internal quantum efficiency is not particularly limited until reaching the theoretical upper limit of 1.0, but is usually 0.95 or less. The absorptance of the phosphor of the present invention is preferably 0.70 or more, particularly 0.72 or more when measured with respect to 450 nm excitation light. The upper limit of the absorption rate is usually 0.95 or less.

  EXAMPLES Hereinafter, although a reference example, an Example, and a comparative example are given and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Reference Example 1]
[Preparation of K ₂ MnF ₆ ]
In accordance with the method described in Non-Patent Document 4, it was prepared by the following method.
A fluororesin-based ion exchange membrane partition (diaphragm) was provided at the center of the reaction vessel made of vinyl chloride resin, and an anode and a cathode each made of a platinum plate were installed in each of the two chambers sandwiching the ion exchange membrane. A hydrofluoric acid aqueous solution in which manganese (II) was dissolved was placed on the anode side of the reaction tank, and a hydrofluoric acid aqueous solution was placed on the cathode side. Both electrodes were connected to a power source, and electrolysis was performed at a voltage of 3 V and a current of 0.75 A. After the electrolysis, an excessive solution of potassium fluoride saturated with an aqueous hydrofluoric acid solution was added to the reaction solution on the anode side. The produced yellow solid product was separated by filtration and recovered to obtain K ₂ MnF ₆ .

[Reference Example 2]
[Fabrication of phosphor as raw material 1]
First, 156 cm ³ of a 40% by mass hydrosilicic acid (H ₂ SiF ₆ ) aqueous solution (Morita Chemical Co., Ltd.) was first added to 50% by mass hydrofluoric acid (HF) (SA-X, Stella Chemifa Co., Ltd.). ) Mixed with 2,740 cm ³ . To this, 22.2 g of K ₂ MnF ₆ powder prepared in advance by the method of Reference Example 1 was added and stirred to dissolve (first solution: Si—F—Mn).
Separately, 140.3 g of potassium hydrogen fluoride (acidic potassium fluoride manufactured by Stella Chemifa, KHF ₂ ) was mixed with 1,990 cm ³ of pure water and dissolved (second solution: K—H—F).
While stirring the first solution at room temperature (16 ° C.) using a stirring blade and a motor, the second solution (15 ° C.) was added little by little over 1 minute 30 seconds. The temperature of the liquid became 26 ° C., and a pale orange precipitate (K ₂ SiF ₆ : Mn) was formed. After further stirring for 10 minutes, the precipitate was filtered off with a Buchner funnel and drained as much as possible. Further washed with acetone, draining, and dried in vacuo, K ₂ SiF _6: to obtain a powder product 130.3g of Mn.
The particle size distribution of the obtained powder product was measured with an airflow dispersion type laser diffraction particle size distribution analyzer (HELOS & RODOS, manufactured by Sympatec). As a result, particles having a particle size of 2.49 μm or less were 10% of the total volume (D10 = 2.49 μm), particles having a particle size of 7.72 μm or less were 50% of the total volume (D50 = 7.72 μm), and particle size 12 Particles of less than 2 μm accounted for 90% of the total volume (D90 = 12.2 μm).
A part of the product was taken and completely dissolved in dilute hydrochloric acid, and the content of Mn was analyzed by ICP emission spectroscopic analysis. As a result, it was 1.42% by mass. The Si content was 11.2% by mass. When calculated from these values, the molar ratio [Mn / (Mn + Si)] was 0.0650.

[Reference Example 3]
[Fabrication of phosphor as raw material 2]
Of 40 wt% silicate aqueous hydrofluoric acid 234cm ^3, it was first mixed with 50 wt% hydrofluoric acid 2,660cm ^3. To this, 15.27 g of K ₂ MnF ₆ powder prepared in advance by the method of Reference Example 1 was added and dissolved by stirring (first solution: Si—F—Mn).
Separately, 156.6 g of potassium fluoride (anhydrous potassium fluoride, KF manufactured by Stella Chemifa) was mixed with 1,930 cm ³ of pure water and dissolved (second solution: K-F).
While stirring the first solution at room temperature (16 ° C.) using a stirring blade and a motor, the second solution (15 ° C.) was added little by little over 1 minute 30 seconds. The temperature of the liquid reached 28 ° C., and a pale orange precipitate (K ₂ SiF ₆ : Mn) was formed. After further stirring for 10 minutes, the precipitate was filtered off with a Buchner funnel and drained as much as possible. Further washed with acetone, draining, and dried in vacuo, K ₂ SiF _6: to obtain a powder product 187.3g of Mn.
The results of the particle size distribution measured in the same manner as in Reference Example 2 were D10 = 0.76 μm, D50 = 3.04 μm, and D90 = 6.07 μm. Further, the composition analysis was conducted in the same manner as in Reference Example 2. As a result, the Mn content was 0.79% by mass, and the Si content was 11.5% by mass. When calculated from these values, the molar ratio [Mn / (Mn + Si)] = 0.0351.

[Reference Example 4]
[Preparation of raw material K ₂ SiF ₆ ]
Of 40 wt% silicate aqueous hydrofluoric acid 390cm ^3, was first mixed with 50 wt% hydrofluoric 150 cm ³ of pure water 2,350cm ^3. (First solution: Si-F).
Separately, 350.8 g of potassium hydrogen fluoride was mixed with 1,930 cm ³ of pure water and dissolved (second solution: K—H—F).
While stirring the first solution at room temperature (16 ° C.) using a stirring blade and a motor, the second solution (15 ° C.) was added little by little over 1 minute 30 seconds. The temperature of the liquid became 22 ° C., and a white translucent precipitate (K ₂ SiF ₆ ) was formed. After further stirring for 10 minutes, the precipitate was filtered off with a Buchner funnel and drained as much as possible. Further washed with acetone, draining, and dried in vacuo to obtain a powder product 324.3g of K ₂ SiF _6.
The results of the particle size distribution measured in the same manner as in Reference Example 2 were D10 = 0.49 μm, D50 = 1.09 μm, and D90 = 2.44 μm.

[Example 1]
Put 52.93 g of K ₂ SiF ₆ : Mn powder obtained in Reference Example 2 and 3.34 g of K ₂ MnF ₆ powder obtained in Reference Example 1 (corresponding to 0.0135 mol of Mn) in the same bag with polyethylene chuck. I put it in. The mixture was shaken by hand or slowly rotated for 5 minutes. The molar ratio [Mn / (Si + Mn)] during mixing corresponds to 0.118.
To this mixed powder, 24.73 g of powder of hydrogen fluoride salt (acidic potassium fluoride (S), KF · 2HF manufactured by Stella Chemifa) was further added and mixed in the same manner as described above.
The powder mixture was placed in a double container 1 (inner container volume: 125 cm ³ ) having the structure shown in FIG. 1 and sealed. Here, in FIG. 1, a double container 1 is formed by forming an inner layer 3 made of polytetrafluoroethylene on the inner wall of a stainless steel (SUS) container body 2, and the double container 1 contains powder. The mixture 10 was put in, sealed with a lid 4 made of SUS, and heated in an oven. The temperature was 250 ° C. and the time was maintained for 12 hours, followed by natural cooling.

As a cleaning solution, a solution prepared by dissolving 8.2 g of potassium silicofluoride (K ₂ SiF ₆ manufactured by Morita Chemical Co., Ltd.) in 220 cm ³ of 50% by mass hydrofluoric acid was prepared. Of these, the above reaction product was added to 200 cm ³ and allowed to stand for 10 minutes with stirring. The massive part was loosened and became powdery. The powdery precipitate was filtered off with a Buchner funnel and washed by sprinkling with the rest of the previously prepared cleaning solution. Further, it was washed with acetone and collected, and then dried in vacuum. 62.47 g of powder product was obtained.
The results of the particle size distribution measured in the same manner as in Reference Example 2 were D10 = 15.1 μm, D50 = 23.3 μm, and D90 = 34.4 μm. Further, the composition analysis was conducted in the same manner as in Reference Example 2. As a result, the Mn content was 2.31% by mass, and the Si content was 10.7% by mass. When calculated from these values, the molar ratio [Mn / (Mn + Si)] = 0.110.

[Example 2]
54.81 g of K ₂ SiF ₆ : Mn powder obtained in Reference Example 3 and 2.44 g of K ₂ MnF ₆ powder obtained in Reference Example 1 (equivalent to Mn 0.0099 mol) were mixed in the same manner as in Example 1. did. The molar ratio [Mn / (Si + Mn)] during mixing corresponds to 0.073.
To this mixed powder, 25.29 g of KF · 2HF powder was further added and mixed in the same manner as in Example 1. Thereafter, the reaction was carried out in the same manner as in Example 1.
The same cleaning liquid as in Example 1 was prepared and treated in the same manner, followed by solid-liquid separation, acetone cleaning, and vacuum drying. 61.84 g of powder product was obtained.
The results of the particle size distribution measured in the same manner as in Reference Example 2 were D10 = 11.9 μm, D50 = 17.8 μm, and D90 = 25.9 μm. Further, the composition analysis was conducted in the same manner as in Reference Example 2. As a result, the Mn content was 1.44% by mass and the Si content was 11.2% by mass. When calculated from these values, the molar ratio [Mn / (Mn + Si)] was 0.0659.

[Comparative Example 1]
Example 1 was obtained by using 52.85 g of K ₂ SiF ₆ powder obtained in Reference Example 4 (corresponding to 0.24 mol of Si) and 2.46 g of K ₂ MnF ₆ powder obtained in Reference Example 1 (corresponding to 0.0100 mol of Mn). And mixed in the same manner. The molar ratio [Mn / (Si + Mn)] during mixing corresponds to 0.040.
To this mixed powder, 24.52 g of KF · 2HF powder was further added and mixed in the same manner as in Example 1. Thereafter, the reaction was carried out in the same manner as in Example 1.
The same cleaning liquid as in Example 1 was prepared and treated in the same manner, followed by solid-liquid separation, acetone cleaning, and vacuum drying. 60.66 g of powder product was obtained.
The results of the particle size distribution measured in the same manner as in Reference Example 2 were D10 = 10.1 μm, D50 = 16.2 μm, and D90 = 24.0 μm. Further, the composition analysis was conducted in the same manner as in Reference Example 2. As a result, the Mn content was 0.77% by mass, and the Si content was 11.6% by mass. When calculated from these values, the molar ratio [Mn / (Mn + Si)] = 0.0339.

[Comparative Example 2]
Of 40 wt% silicate aqueous hydrofluoric acid 156cm ^3, it was first mixed with 50 wt% hydrofluoric acid 2,740cm ^3. To this, 44.4 g of K ₂ MnF ₆ powder prepared in advance by the method of Reference Example 1 was added and stirred to dissolve (first solution: Si—F—Mn).
Separately was a hydrogen fluoride of potassium 140.3g was mixed with 50 wt% hydrofluoric 260 cm ³ of pure water 1,730Cm ³ dissolved (second solution: K-H-F).
While stirring the first solution at room temperature (16 ° C.) using a stirring blade and a motor, the second solution (15 ° C.) was added little by little over 1 minute 30 seconds. The temperature of the liquid became 26 ° C., and a pale orange precipitate (K ₂ SiF ₆ : Mn) was formed. After further stirring for 10 minutes, the precipitate was filtered off with a Buchner funnel and drained as much as possible. Further washed with acetone, draining, and dried in vacuo, K ₂ SiF _6: to obtain a powder product 135.5g of Mn.
The results of the particle size distribution measured in the same manner as in Reference Example 2 were D10 = 5.92 μm, D50 = 13.3 μm, and D90 = 19.8 μm. Further, the composition analysis was conducted in the same manner as in Reference Example 2. As a result, the Mn content was 2.71% by mass, and the Si content was 10.5% by mass. When calculated from these values, the molar ratio [Mn / (Mn + Si)] = 0.132.

Table 1 shows the molar ratio [Mn / (Mn + Si)] as a composition of the products obtained by the above reference examples (K ₂ SiF ₆ : Mn only), Examples and Comparative Examples and the center particle diameter (D50) as a reference. Shown in the list.

[Characteristic evaluation]
The emission spectra and excitation spectra of the phosphors obtained in the reference examples, examples and comparative examples were measured with a fluorometer FP6500 (manufactured by JASCO Corporation). All spectra are similar. As a representative, the results of the product of Example 1 are shown in FIG. The maximum peak of the emission spectrum was 631.4 nm, and its width (half-value width measured at half the peak height) was 3.8 nm.
Moreover, the absorption factor and quantum efficiency in excitation wavelength 450nm were measured using quantum efficiency measuring apparatus QE1100 (made by Otsuka Electronics Co., Ltd.). Table 2 shows the absorptance and quantum efficiency at an excitation wavelength of 450 nm.

[Evaluation experiment]
The test light emitting device shown in FIG. 3 was produced. The chip 11 is an InGaN blue light emitting diode (SMTB470 manufactured by Epitex). Reference numerals 12 and 13 denote electrical connection portions, which are embedded in the opaque base housing 18 at the recessed portion 19. The connecting portion 12 is in electrical contact with the lower electrode of the chip 11, and the connecting portion 13 is electrically connected to the upper electrode via a bonding wire 14. The wall surface 17 of the recess 19 reflects visible light. A liquid thermosetting resin 15 in which the phosphor 16 is previously kneaded is injected into the recess 19 and cured.
Silicone resin as the resin (Ker-6020A / B manufactured by Shin-Etsu Chemical Co., Ltd., two-component type, A and B mixed together when used), red phosphor of Example 1 and Comparative Example 1, yellow phosphor A cerium activated yttrium aluminum garnet (Y _2.94 Ce _0.06 Al ₅ O ₁₂ , abbreviated YAG) was used. The average particle size of the YAG phosphor was 2.65 μm, and the internal quantum efficiency measured by the conditions and method described above was 0.94. Silicone and phosphor were mixed in the composition (weight) shown in Table 3, and after being injected into the LED as shown in FIG. 3, the resin was cured by heating in an oven (atmosphere) kept at 120 ° C. for 30 minutes.
The obtained LED is attached to a total luminous flux measuring device (half moon φ500 mm) manufactured by Otsuka Electronics Co., Ltd., lit at a constant current of 350 mA (applied voltage of 3.0 V at this time), an emission spectrum is measured, and the color of emitted light The values calculated for the degrees are also listed in Table 3.

FIG. 4 shows the spectrum of the LED 1 as an example of the spectrum of the LED composed of the blue LED and the red phosphor, and FIG. 5 shows the spectrum of the LED 2 as an example of the spectrum composed of the blue LED, the red phosphor and further the YAG phosphor.
FIG. 6 shows the chromaticity of the LEDs 2 to 7 (Example) and the LEDs 8 to 13 (Comparative Example) on the x and y chromaticity diagrams. It can be seen that with the same amount of mixing ratio, the embodiment is warmer, that is, closer to red.

  Although the present invention has been described with the embodiment, the present invention is not limited to the embodiment, and other embodiments, additions, changes, deletions, and the like can be conceived by those skilled in the art. As long as the effects of the present invention are exhibited in any aspect, they are included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Double container 2 Container body 3 Inner layer 4 Lid 10 Powder mixture 11 Blue LED chip 12, 13 Electrical connection part 14 Bonding wire 15 Thermosetting resin 16 Phosphor 17 Wall surface with reflector (frame)
18 Base housing 19 Recessed space

Claims (4)

Following formula (1)
K ₂ MF ₆ : Mn (1)
(In the formula, M is one or two or more tetravalent elements selected from Si, Ti, Zr, Hf, Ge, and Sn, and necessarily includes Si.)
A method for producing a Mn-activated double fluoride phosphor, comprising mixing a solid of K ₂ MnF ₆ with a red phosphor, which is a Mn-activated double fluoride represented by the formula, and heating at 100 ° C. to 500 ° C. . Together with the above K ₂ MnF ₆ , the following formula (2)
AF / nHF (2)
(In the formula, A is one or two or more alkali metals or ammonium selected from Li, Na, K, Rb, and NH ₄ , and must include K, and n is a number of 0.7 or more and 4 or less. .)
The method for producing a Mn-activated double fluoride phosphor according to claim 1, wherein the hydrogen fluoride salt represented by the formula is mixed as a solid.   3. The reaction mixture obtained by heating is washed with an inorganic acid solution or a fluoride salt solution to remove unnecessary components, followed by solid-liquid separation and drying of the solid content. A method for producing a Mn-activated double fluoride phosphor. Following formula (1)
K ₂ MF ₆ : Mn (1)
(In the formula, M is one or two or more tetravalent elements selected from Si, Ti, Zr, Hf, Ge, and Sn, and necessarily includes Si.)
A red phosphor that is a Mn-activated bifluoride represented by the following formula (3)
Mn / (M + Mn) (3)
The ratio of the number of moles or the number of atoms represented by the formula is 0.1 or more and 0.25 or less, the internal quantum efficiency of fluorescence by excitation light of 450 nm is 0.842 or more , and the absorptance is 0.72 or more. A featured Mn-activated double fluoride phosphor.

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