Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent materials, e.g. electroluminescent or chemiluminescent
  • C09K11/08—Luminescent materials, e.g. electroluminescent or chemiluminescent containing inorganic luminescent materials
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent materials, e.g. electroluminescent or chemiluminescent
  • C09K11/08—Luminescent materials, e.g. electroluminescent or chemiluminescent containing inorganic luminescent materials
  • C09K11/64—Luminescent materials, e.g. electroluminescent or chemiluminescent containing inorganic luminescent materials containing aluminium
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent materials, e.g. electroluminescent or chemiluminescent
  • C09K11/08—Luminescent materials, e.g. electroluminescent or chemiluminescent containing inorganic luminescent materials
  • C09K11/64—Luminescent materials, e.g. electroluminescent or chemiluminescent containing inorganic luminescent materials containing aluminium
  • C09K11/644—Halogenides
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/80—Constructional details
  • H10H20/85—Packages
  • H10H20/851—Wavelength conversion means
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/80—Constructional details
  • H10H20/85—Packages
  • H10H20/851—Wavelength conversion means
  • H10H20/8511—Wavelength conversion means characterised by their material, e.g. binder

Definitions

• the present invention relates to surface-coated phosphor particles, a method for producing surface-coated phosphor particles, and a light emitting device.
• Light emitting devices formed by combining light emitting diodes (LEDs) and phosphors are widely used in lighting devices, backlights of liquid crystal display devices, and the like.
• LEDs light emitting diodes
• phosphors having a narrow full width at half maximum (hereinafter, simply referred to as "full width at half maximum") of the fluorescence spectrum. ..
• a nitride phosphor or an oxynitride phosphor activated by Eu 2+ is known.
• Typical pure nitride phosphors include Sr 2 Si 5 N 8 : Eu 2+ , CaAlSiN 3 : Eu 2+ (abbreviated as CASN), (Ca, Sr) AlSiN 3 : Eu 2+ (abbreviated as SCANSN). )and so on.
• the CASN phosphor and the SCASN phosphor have a peak wavelength in the range of 610 to 680 nm, and the half width thereof is relatively narrow as 75 nm or more and 90 nm or less.
• these phosphors are used as a light emitting device for a liquid crystal display, further expansion of the color reproduction range is desired, and a phosphor having a narrower half-value width is desired.
• an SrLiAl 3 N 4 : Eu 2+ (abbreviated as SLAN) phosphor has been known as a narrow band red phosphor having a half-value width of 70 nm or less, and a light emitting device applying this phosphor has excellent color rendering properties. And color reproducibility can be expected.
• Patent Document 1 discloses an SLAN phosphor having a specific composition.
• the SLAN phosphor has the property of being easily decomposed when it comes into contact with water. This property causes the emission intensity to decrease with the passage of time. In recent years, further improvement in reliability of a light emitting device using an SLAN phosphor has been required, and further improvement in moisture resistance of the SLAN phosphor has also been required.
• the particle surface is composed of at least a fluorine-containing compound and the particle surface is composed of at least a fluorine-containing compound. It has been found that the decrease in fluorescence intensity in a water-exposed environment can be suppressed, that is, the moisture resistance can be improved by setting the content of the fluorine element with respect to the entire particles to a predetermined value or more.
• the surface-coated phosphor particles include particles containing a phosphor and a coating portion that covers the surface of the particles, and the phosphor is a general formula M 1 a M 2 b M 3 c Al 3 N 4-d Od (where M 1 is one or more elements selected from Sr, Mg, Ca and Ba, and M 2 is one or more elements selected from Li and Na. , M 3 is one or more elements selected from Eu and Ce), and the a, b, c, and d satisfy the following formulas.
• the coating portion comprises at least a part of the outermost surface of the particles and contains a fluorine-containing compound containing a fluorine element and an aluminum element.
• a fluorine-containing compound containing a fluorine element and an aluminum element.
• surface-coated phosphor particles having a fluorine element content of 15% by mass or more and 30% by mass or less with respect to the entire surface-coated phosphor particles.
• a mixing step of mixing raw materials, a firing step of firing the mixture obtained by the mixing step, and a firing step of firing the mixture obtained by the mixing step are obtained.
• Al includes an acid treatment step of mixing the fired product and an acidic solution, and a fluorine treatment step of mixing the fired product that has undergone the acid treatment step with a compound containing a fluorine element.
• a light emitting device having the above-mentioned surface-coated phosphor particles and a light emitting element is provided.
• the surface-coated phosphor particles according to the embodiment include particles containing a phosphor and a coating portion that covers the surface of the particles. The details of the surface-coated phosphor particles will be described below.
• the phosphor constituting the particles of the present embodiment is represented by the general formula M 1 a M 2 b M 3 c Al 3 N 4-d Od . a, b, c, 4-d, and d indicate the molar ratio of each element.
• M 1 is one or more elements selected from Sr, Mg, Ca and Ba.
• M 1 comprises at least Sr.
• the lower limit of the molar ratio a of M 1 is preferably 0.850 or more, more preferably 0.950 or more.
• the upper limit of the molar ratio a of M 1 is preferably 1.150 or less, more preferably 1.100 or less, and even more preferably 1.050 or less.
• M 2 is one or more elements selected from Li and Na.
• M 2 contains at least Li.
• Molar ratio lower limit of b of M 2 is preferably not less than 0.850, more preferably not less than 0.950.
• the upper limit of the molar ratio b of M 2 is preferably 1.150 or less, more preferably 1.100 or less, more preferably 1.050 or less.
• the molar ratio a of M 2 is in the above range, it is possible to improve the crystal structure stability.
• M 3 is an activator added to the mother crystal, that is, an element constituting the emission center ion of the phosphor, and is one or more elements selected from Eu and Ce.
• M 3 can be selected according to the required emission wavelength, and preferably contains at least Eu.
• the lower limit of the molar ratio c of M 3 is preferably 0.001 or more, and more preferably 0.005 or more.
• the upper limit of the molar ratio c of M 3 is preferably 0.015 or less, more preferably 0.010 or less.
• the lower limit of the molar ratio d of oxygen is preferably 0 or more, more preferably 0.05 or more.
• the upper limit of the molar ratio d of oxygen is preferably 0.40 or less, more preferably 0.35 or less.
• the lower limit of the molar ratio of M 1 and oxygen that is, the value of d / (a + d) calculated from a and d is preferably 0 or more, and more preferably 0.05 or more.
• the upper limit of the value of d / (a + d) is preferably less than 0.30, more preferably 0.25 or less.
• the covering portion constitutes at least a part of the outermost surface of the particles containing the above-mentioned phosphor.
• the coating contains a fluorine-containing compound containing a fluorine element and an aluminum element.
• the fluorine-containing compound it is preferable that the fluorine element and the aluminum element are directly covalently bonded, and more specifically, the fluorine-containing compound is one or both of (NH 4 ) 3 AlF 6 and AlF 3. Is preferably included.
• the fluorine-containing compound may be composed of a single compound containing a fluorine element and an aluminum element.
• the moisture resistance of the phosphor constituting the particles can be improved. From the viewpoint of further improving the moisture resistance of the phosphor, it is more preferable that the coating portion contains AlF 3 .
• the mode of the covering portion is not particularly limited, but the covering portion may be configured to cover at least a part of the particle surface, and may be configured to cover the entire particle surface.
• Examples of the mode of the coating portion include a mode in which a large number of particulate fluorine-containing compounds are distributed on the surface of the particles containing the phosphor, and a mode in which the fluorine-containing compound continuously covers the surface of the particles containing the phosphor. Can be mentioned.
• the content of the fluorine element with respect to the entire surface-coated phosphor particles is 15% by mass or more and 30% by mass or less.
• Moisture resistance can be enhanced by setting the content of the fluorine element to the entire surface-coated phosphor particles to be 15% by mass or more.
• the lower limit of the content of the fluorine element with respect to the entire surface-coated phosphor particles is more preferably 18% by mass or more, further preferably 20% by mass or more.
• the upper limit of the content of the fluorine element with respect to the entire surface-coated phosphor particles is more preferably 27% by mass or less, further preferably 25% by mass or less.
• the moisture resistance can be further enhanced.
• the upper limit of the content of the fluorine element in the above range it is possible to further improve the moisture resistance and maintain the emission intensity at a sufficient value.
• the fluorine element is derived from the fluoride of the metal element used as a raw material, which will be described later, or is added by the fluorine treatment step described later, and does not constitute the crystal structure of the phosphor.
• the fluorescence intensity in a water exposure environment can be suppressed, the decrease in the fluorescence intensity in a high humidity environment such as 90% RH or more can be suppressed, and more preferably the high temperature and high temperature. It is possible to suppress a decrease in fluorescence intensity in a humid environment.
• the diffuse reflectance of the surface-coated phosphor particles of the present embodiment with respect to light irradiation at a wavelength of 300 nm is, for example, 56% or more, more preferably 58% or more, and more preferably 60% or more. Further, the diffuse reflectance of the surface-coated phosphor particles with respect to light irradiation at the peak wavelength of the fluorescence spectrum is, for example, 85% or more, preferably 86% or more. By providing such characteristics, the luminous efficiency is further increased and the luminous intensity is improved.
• An example of the surface-coated phosphor particles of the present embodiment preferably has a peak wavelength in the range of 640 nm or more and 670 nm or less and a half width of 45 nm or more and 60 nm or less when excited by blue light having a wavelength of 455 nm. By providing such characteristics, excellent color rendering and color reproducibility can be expected.
• An example of the surface-coated phosphor particles of the present embodiment has a color purity of emission color of 0.680 ⁇ x ⁇ 0.735 in the CIE-xy chromaticity diagram when excited by blue light having a wavelength of 455 nm. It is preferable to meet. By providing such characteristics, excellent color rendering and color reproducibility can be expected. If the x value is 0.680 or more, red light emission with good color purity can be further expected, and if the x value is 0.735 or more, it exceeds the maximum value in the CIE-xy chromaticity diagram, so the above range is satisfied. Is preferable.
• the type of acid and solvent in the acid treatment step, the concentration of the acid, the concentration of hydrofluoric acid in the hydrofluoric acid treatment step, the time of the hydrofluoric acid treatment, the heating temperature and the heating time in the heating step performed after the hydrofluoric acid treatment By appropriately adjusting the above, a fluorine-containing compound containing a fluorine element and an aluminum element can be formed on the surface of the particles containing a phosphor, and the content of the fluorine element in the particles can be controlled within a desired range. Can be done.
• the moisture resistance of the nitride phosphor can be enhanced by coating the surface of the phosphor particles with a coating portion containing a fluorine-containing compound containing a fluorine element and an aluminum element. As a result, the emission intensity can be maintained for a long period of time.
• the surface-coated phosphor particles of the present embodiment are a mixing step of mixing raw materials, a firing step of firing the mixture obtained by the mixing step, and an acid treatment step of mixing the fired product obtained by the firing step and an acidic solution. It can be produced by a fluorine treatment step of mixing a fired product that has undergone the acid treatment step and a compound containing a fluorine element. In addition to the above steps, it is preferable to add a heating step of applying a heat treatment to the result product obtained by the fluorine treatment step.
• the mixing step is a step of mixing each of the raw materials weighed so as to obtain the desired surface-coated phosphor particles to obtain a powdered raw material mixture.
• the method of mixing the raw materials is not particularly limited, but for example, there is a method of sufficiently mixing using a mixing device such as a mortar, a ball mill, a V-type mixer, and a planetary mill.
• a mixing device such as a mortar, a ball mill, a V-type mixer, and a planetary mill.
• Strontium nitride, lithium nitride, etc. which react violently with moisture and oxygen in the air, should be handled in a glove box in which the inside is replaced with an inert atmosphere or by using a mixing device.
• the amount of M 1 charged when the molar ratio of Al is 3 is 1.10 or more in terms of molar ratio.
• the amount of M 1 charged it is possible to prevent the shortage of M 1 in the phosphor due to volatilization of M 1 during the firing process, and it is difficult for defects to occur in M 1. , The crystallinity of the crystal structure is kept good. As a result, a narrow-band fluorescence spectrum can be obtained, and it is presumed that the emission intensity can be increased.
• the amount of M 1 charged when the molar ratio of Al is 3 is 1.20 or less in terms of molar ratio.
• Each raw material used in the mixing step can include one or more selected from the group consisting of a simple substance of a metal element contained in the composition of a phosphor and a metal compound containing the metal element.
• the metal compound include nitrides, hydrides, fluorides, oxides, carbonates, chlorides and the like. Of these, nitrides are preferably used as the metal compound containing M 1 and M 2 from the viewpoint of improving the emission intensity of the phosphor.
• a metal compound containing M 1, Sr 3 N 2, SrN 2, etc. SrN the like.
• the metal compound containing M 2 include Li 3 N and Li N 3 .
• the metal compound containing M 3 include Eu 2 O 3 , Eu N, and Eu F 3 .
• Examples of the metal compound containing Al include AlN, AlH 3 , AlF 3 , LiAlH 4 and the like. If necessary, flux may be added. Examples of the flux include LiF, SrF 2 , BaF 2 , AlF 3, and the like.
• the firing container preferably has a structure capable of enhancing airtightness, and the inside of the firing container is preferably filled with an atmospheric gas of a non-oxidizing gas such as argon, helium, hydrogen, or nitrogen.
• the firing vessel is preferably made of a material that is stable under high temperature atmospheric gas and does not easily react with the mixture of raw materials and the reaction product thereof.
• the lower limit of the firing temperature in the firing step is preferably 900 ° C. or higher, more preferably 1000 ° C. or higher, and even more preferably 1100 ° C. or higher.
• the upper limit of the firing temperature is preferably 1500 ° C. or lower, more preferably 1400 ° C. or lower, and even more preferably 1300 ° C. or lower.
• Type of firing atmosphere gas As the type of firing atmosphere gas in the firing step, for example, a gas containing nitrogen as an element can be preferably used. Specific examples include nitrogen and / or ammonia, with nitrogen being particularly preferred. Similarly, an inert gas such as argon or helium can also be preferably used.
• the firing atmosphere gas may be composed of one type of gas or a mixed gas of a plurality of types of gases.
• the pressure of the firing atmosphere gas is selected according to the firing temperature, but is usually in a pressurized state in the range of 0.1 MPa ⁇ G or more and 10 MPa ⁇ G or less.
• the firing time in the firing step a time range is selected in which a large amount of unreacted substances are not present, the phosphor particles are insufficiently grown, or the productivity is not lowered.
• the lower limit of the firing time is preferably 0.5 hours or more, more preferably 1 hour or more, still more preferably 2 hours or more.
• the upper limit of the firing time is preferably 48 hours or less, more preferably 36 hours or less, and even more preferably 24 hours or less.
• the state of the fired product obtained by the firing process varies from powdery to lumpy depending on the raw material composition and firing conditions.
• a crushing / crushing step and / or a classification operation step of converting the obtained fired product into a powder having a predetermined size may be provided in preparation for actual use as surface-coated phosphor particles.
• the average particle size of the surface-coated fluorophore particles is the same as that of the surface-coated phosphor particles when used as the surface-coated phosphor particles for LEDs, from the viewpoint of obtaining excitation light absorption efficiency and sufficient emission efficiency. It is preferable to adjust so that the average particle size is 5 ⁇ m or more and 30 ⁇ m or less.
• the member of the device in contact with the fired product is made of high toughness ceramics such as silicon nitride, alumina, and sialon.
• the acidic solution used in the acid treatment step is preferably an aqueous solution, and the contact with the acidic solution is described above in an acidic aqueous solution containing one or more of nitric acid, hydrochloric acid, acetic acid, sulfuric acid, formic acid and phosphoric acid, for example.
• a general method is to disperse the calcined product and stir for several minutes to several hours.
• the above-mentioned fired product can be dispersed in a mixed solution of an organic solvent and an acidic solution, stirred for several minutes to several hours, and then washed with an organic solvent.
• impurity elements contained in the raw material, impurity elements derived from the firing container, different phases generated in the firing step, and impurity elements mixed in the crushing step can be dissolved and removed. Since it is possible to remove fine powder at the same time, light scattering can be suppressed and the light absorption rate of the phosphor can be improved.
• the organic solvent alcohols such as methanol, ethanol and 2-propanol and ketones such as acetone can be used.
• the acidic solution is one or more of nitric acid, hydrochloric acid, acetic acid, sulfuric acid, formic acid, and phosphoric acid. The mixing ratio of these solutions is, for example, adjusted so that the acidic solution has a concentration of 0.1% by volume or more and 3% by volume or less with respect to the organic solvent.
• a hydrofluoric acid aqueous solution is preferably used as a compound containing a fluorine element to be mixed with the fired product that has undergone the acid treatment step.
• the lower limit of the concentration of the hydrofluoric acid aqueous solution is preferably 25% or more, more preferably 27% or more, still more preferably 30% or more.
• the upper limit of the concentration of the hydrofluoric acid aqueous solution is preferably 38% or less, more preferably 36% or less, still more preferably 34% or less.
• a coating portion containing (NH 4 ) 3 AlF 6 can be formed on at least a part of the outermost surface of the particles containing the phosphor.
• concentration of the hydrofluoric acid aqueous solution can be set to 38% or less, it is possible to prevent the reaction between the particles and hydrofluoric acid from becoming too violent.
• the fired product that has undergone the acid treatment step and the hydrofluoric acid aqueous solution can be mixed by a stirring means such as a stirrer.
• the lower limit of the mixing time of the fired product and the aqueous solution of hydrofluoric acid is preferably 5 minutes or more, more preferably 10 minutes or more, and even more preferably 15 minutes or more.
• the upper limit of the mixing time of the fired product and the aqueous solution of hydrofluoric acid is preferably 30 minutes or less, more preferably 25 minutes or less, still more preferably 20 minutes or less.
• a heating step may be carried out after the above steps.
• the lower limit of the heating temperature in the heating step is preferably 220 ° C. or higher, more preferably 250 ° C. or higher.
• the upper limit of the heating temperature is preferably 500 ° C. or lower, more preferably 450 ° C. or lower, and even more preferably 400 ° C. or lower.
• the heating temperature is set to 500 ° C. or lower, the crystal structure of the phosphor can be maintained well and the emission intensity can be increased.
• the lower limit of the heating time is preferably 1 hour or more, more preferably 1.5 hours or more, still more preferably 2 hours or more.
• the upper limit of the heating time is preferably 6 hours or less, more preferably 5.5 hours or less, and even more preferably 5 hours or less.
• the heating step is preferably carried out in the air or in a nitrogen atmosphere. According to this, the target substance can be produced without the substance itself in the heating atmosphere hindering the above reaction formula (1).
• the light emitting device includes the surface-coated phosphor particles of the above-described embodiment and a light emitting element.
• a light emitting element an ultraviolet LED, a blue LED, a fluorescent lamp alone, or a combination thereof can be used.
• the light emitting element is preferably one that emits light having a wavelength of 250 nm or more and 550 nm or less, and particularly preferably a blue LED light emitting element of 420 nm or more and 500 nm or less.
• fluorescent particles having other emission colors can be used in combination.
• the phosphor particles having other emission colors include blue emission phosphor particles, green emission phosphor particles, yellow emission phosphor particles, orange emission phosphor particles, and red phosphor.
• blue emission phosphor particles green emission phosphor particles
• yellow emission phosphor particles yellow emission phosphor particles
• orange emission phosphor particles and red phosphor.
• Ca 3 Sc 2 Si 3 O For example, Ca 3 Sc 2 Si 3 O.
• the phosphor particles that can be used in combination with the surface-coated phosphor particles of the above-described embodiment are not particularly limited, and can be appropriately selected depending on the brightness, color rendering property, and the like required for the light emitting device.
• Light emitting devices include a lighting device, a backlight device, an image display device, and a signal device.
• the light emitting device of this embodiment can improve reliability while realizing high light emitting intensity.
• Sr 3 N 2 manufactured by Pacific Cement
• Li 3 N manufactured by Matterion
• AlN manufactured by Tokuyama
• Eu 2 O 3 manufactured by Shin-Etsu Chemical Industries
• LiF Japanese Wako
• the container filled with the raw material mixture of the phosphor After taking out the container filled with the raw material mixture of the phosphor from the glove box, it was set in an electric furnace (manufactured by Fuji Denpa Kogyo Co., Ltd.) equipped with a graphite heat insulating material and equipped with a carbon heater, and a firing step was carried out.
• the inside of the electric furnace was once degassed to a vacuum state, and then firing was started in a pressurized nitrogen atmosphere of 0.8 MPa ⁇ G from room temperature. After the temperature in the electric furnace reached 1100 ° C., firing was continued while maintaining the temperature for 8 hours, and then cooled to room temperature.
• the obtained calcined product was pulverized in a mortar, classified with a nylon sieve having an opening of 75 ⁇ m, and recovered.
• As an acid treatment step after adding the powder of the calcined product to a mixed solution of MeOH (99%) (manufactured by Kokusan Kagaku Co., Ltd.) and HNO 3 (60%) (manufactured by Wako Pure Chemical Industries, Ltd.) and stirring for 3 hours. , Classified to obtain a phosphor powder.
• the obtained fluorescent powder was added to a 30% aqueous hydrofluoric acid solution, and the mixture was stirred for 15 minutes to carry out a fluorine treatment step.
• the solution is washed by decantation with MeOH until the solution becomes neutral, solid-liquid separation is performed by filtration, the solid content is dried, and the solid content is passed through a sieve having a mesh size of 45 ⁇ m. , The agglomeration was released to obtain the surface-coated phosphor particles of Example 1.
• Example 2 The fluorescent powder, which had been subjected to fluorine treatment and then disaggregated by passing through a sieve having a mesh size of 45 ⁇ m, was heat-treated at 250 ° C. for 4 hours in an air atmosphere, except that it was heat-treated.
• the surface-coated phosphor particles of Example 2 were obtained by the same raw material charge amount and procedure as in Example 1.
• Example 3 After being treated with fluorine, the fluorescent powder that had been disaggregated by passing through a sieve with a mesh size of 45 ⁇ m was heat-treated at 300 ° C. for 4 hours in an air atmosphere.
• the surface-coated phosphor particles of Example 3 were obtained by the same amount and procedure of charging raw materials as in Example 1.
• Example 4 After being treated with fluorine, the fluorescent powder that had been disaggregated by passing through a sieve with a mesh size of 45 ⁇ m was heat-treated at 350 ° C. for 4 hours in an air atmosphere.
• the surface-coated phosphor particles of Example 4 were obtained by the same amount and procedure of charging raw materials as in Example 1.
• Example 5 After being treated with fluorine, the fluorescent powder that had been disaggregated by passing through a sieve with a mesh size of 45 ⁇ m was heat-treated at 400 ° C. for 4 hours in an air atmosphere. , The surface-coated phosphor particles of Example 5 were obtained by the same raw material charge amount and procedure as in Example 1.
• Comparative Example 1 The phosphor particles of Comparative Example 1 were obtained by the same raw material charge amount and procedure as in Example 1 except that the fluorine treatment was not performed.
• Comparative Example 2 Fluorescent particles of Comparative Example 2 were obtained by the same raw material charge amount and procedure as in Example 1 except that a 10% hydrofluoric acid aqueous solution was used for the fluorine treatment.
• Comparative Example 3 Fluorescent particles of Comparative Example 3 were obtained by the same raw material charge amount and procedure as in Example 1 except that a 20% hydrofluoric acid aqueous solution was used for the fluorine treatment.
• the total chemical composition of all crystal phases that is, general formula: M 1 a M 2 b M 3 c Al 3 N 4-d Od ).
• the subscripts a to d of each element were obtained.
• the obtained phosphor particles were analyzed by the following method. That is, analysis using an ICP emission spectroscopic analyzer (Spectro, CIROS-120) for Sr, Li, Al and Eu, and an oxygen-nitrogen analyzer (EMGA-920, HORIBA, Ltd.) for O and N. Calculated using the results.
• Table 1 shows the numerical values a to d for the phosphors of Examples and Comparative Examples.
• Example 1 (Analysis by X-ray diffraction method) The crystal structures of the surface-coated fluorescent particles of each example and the fluorescent particles of each comparative example were confirmed by a powder X-ray diffraction pattern using CuK ⁇ rays using an X-ray diffractometer (Ultima IV manufactured by Rigaku Co., Ltd.). ..
• a peak corresponding to (NH 4 ) 3 AlF 6 was confirmed in the range where 2 ⁇ was 16.5 ° or more and 17.5 ° or less.
• Examples 2 to 5 a peak corresponding to AlF 3 was confirmed in the range where 2 ⁇ was 14 ° or more and 15 ° or less.
• the surface-coated phosphor particles of Example 1 at least a part of the outermost surface of the phosphor particles is composed of (NH 4 ) 3 AlF 6 .
• AlF 3 constitutes at least a part of the outermost surface of the phosphor particles.
• Comparative Examples 1 and 2 (NH 4 ) 3 AlF 6 and AlF 3 were not present on the outermost surface of the phosphor particles, and in Comparative Example 3, AlF 3 was not present and was slightly present. (NH 4 ) 3 AlF 6 is considered to be present.
• the content of fluorine element in the entire surface-coated phosphor particles of each example and the content of fluorine element in the entire phosphor particles of each comparative example are determined by a sample combustion device (manufactured by Mitsubishi Chemical Analytech Co., Ltd., AQF-2100H) and ions. It was calculated using the analysis result using a chromatograph (ICS1500 manufactured by Nippon Dionex Co., Ltd.).
• the diffuse reflectance was measured by attaching an integrating sphere device (ISV-469) to an ultraviolet-visible spectrophotometer (V-550) manufactured by JASCO Corporation. Baseline correction is performed with a standard reflector (Spectralon), and a solid sample holder filled with the surface-coated phosphor particles of each example or the phosphor particles of each comparative example is attached, and the diffuse reflectance for light having a wavelength of 300 nm is determined. And the diffuse reflectance for light of peak wavelength was measured.
• the chromaticity x was measured by a spectrophotometer (MCPD-7000 manufactured by Otsuka Electronics Co., Ltd.) and calculated by the following procedure.
• the surface-coated fluorescent particles of each example or the fluorescent particles of each comparative example were filled so that the surface of the concave cell was smooth, and an integrating sphere was attached.
• Blue monochromatic light dispersed at a wavelength of 455 nm from a light source (Xe lamp) was introduced into the integrating sphere using an optical fiber. Using this monochromatic light as an excitation source, a phosphor sample was irradiated, and the fluorescence spectrum of the sample was measured. The peak wavelength and the half width of the peak were obtained from the obtained fluorescence spectrum data.
• the chromaticity x is the CIE chromaticity coordinate x value in the XYZ color system defined by JIS Z 8781-3: 2016 according to JIS Z 8724: 2015 from the wavelength range data in the range of 465 nm to 780 nm of the fluorescence spectrum data. (Saturation x) was calculated.
• the emission intensity I 0 was measured before starting the high temperature and high humidity test. Subsequently, using a thermo-hygrostat (manufactured by Yamato Scientific Co., Ltd., IW-222), the emission intensity I 1 after the high-temperature and high-humidity test of placing in an environment of 60 ° C. and 90% RH for 50 hours was measured. The emission intensity ratio I 1 / I 0 (%) was calculated from the obtained measured values. Further, it was placed in an environment of 60 ° C.
• the emission intensity ratio I 2 / I 0 (%) was calculated from the obtained measured values.
• Table 1 shows the results obtained for the emission intensity ratios I 1 / I 0 and I 2 / I 0 .
• the emission intensity was measured using a spectrofluorometer (F-7000, manufactured by Hitachi High-Technologies Corporation) corrected by Rhodamine B and a sub-standard light source. That is, the fluorescence spectrum at an excitation wavelength of 455 nm was measured using the solid sample holder attached to the photometer.
• the peak wavelength of the fluorescence spectrum of the surface-coated phosphor particles of each example and the phosphor particles of Comparative Example 3 was 656 nm.
• the peak wavelength of the fluorescence spectrum of the phosphor particles of Comparative Examples 1 and 2 was 657 nm.
• the intensity value at the peak wavelength of the fluorescence spectrum was defined as the emission intensity of the surface-coated phosphor particles or the phosphor particles.
• the luminescence intensity ratio I 2 /I 0 after passing through the high temperature and high humidity test for 100 hours is almost the same as the luminescence intensity ratio I 1 / I 0 after passing through the high temperature and high humidity test for 50 hours. It was confirmed that there was no decrease and the moisture resistance was particularly excellent.
• Comparative Example 3 it is considered that sufficient moisture resistance could not be obtained because the amount of (NH 4 ) 3 AlF 6 produced was insufficient.

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