阅读说明：本技术 荧光体粉末、复合体以及发光装置 (Phosphor powder, composite, and light-emitting device ) 是由 野见山智宏 武田雄介 奥园达也 宫崎胜 渡边真太郎 于 2020-03-24 设计创作，主要内容包括：本发明的一个方式是一种由含有Eu的α型塞隆荧光体粒子构成的荧光体粉末。该荧光体粉末的由下述提取离子分析求出的、荧光体粉末的氨离子的浓度C-(A)为15ppm～100ppm。(提取离子分析A)将荧光体粉末0.5g加入到带盖的PTFE(聚四氟乙烯)制容器中的蒸馏水25ml,在60℃保持24小时后,使用离子色谱法求出通过过滤而除去了固体成分的水溶液中包含的氨离子的总质量M-(A)。然后,通过用M-(A)除以荧光体粉末的质量而求出C-(A)。(One embodiment of the present invention is a phosphor powder composed of α -type sialon phosphor particles containing Eu. The concentration C of ammonia ions in the phosphor powder, which was obtained by the following extracted ion analysis, was determined for the phosphor powder A 15ppm to 100 ppm. (analysis of extracted ion A) phosphor powder 0.5g was put into a container made of PTFE (Polytetrafluoroethylene) with a lid and distilled water 25ml was added theretoAfter keeping at 60 ℃ for 24 hours, the total mass M of ammonia ions contained in the aqueous solution from which the solid content was removed by filtration was determined by ion chromatography A . Then, by using M A Dividing by the mass of the phosphor powder to obtain C A 。)

1. A phosphor powder comprising Eu-containing alpha-sialon phosphor particles,

the concentration C of ammonia ions in the phosphor powder was determined by the following extracted ion analysis A_AIs 15ppm to 100ppm of the total amount of the catalyst,

extracted ion analysis a:

0.5g of phosphor powder was added to 25ml of distilled water in a polytetrafluoroethylene container made of PTFE with a cover, and after keeping at 60 ℃ for 24 hours, the total mass M of ammonia ions contained in the aqueous solution from which the solid content was removed by filtration was determined by ion chromatography_ABy M_ADividing by the mass of the phosphor powder to obtain C_A。

2. The phosphor powder according to claim 1, wherein the concentration C of ammonia ions in the phosphor powder is determined by the following extracted ion analysis B_BIs in the range of 50ppm to 250ppm,

extracted ion analysis B:

0.5g of phosphor powder was charged into 25ml of distilled water in a polytetrafluoroethylene container made of PTFE with a lid, and after keeping at 80 ℃ for 24 hours, the total mass M of ammonia ions contained in the aqueous solution from which the solid content was removed by filtration was determined by ion chromatography_BBy M_BDividing by the mass of the phosphor powder to obtain C_B。

3. The phosphor powder according to claim 1 or 2, wherein the concentration C of ammonia ions in the phosphor powder is obtained by the following extracted ion analysis C_cIs in the range of 250ppm to 650ppm,

extracted ion analysis C:

0.5g of phosphor powder was added to 25ml of distilled water in a polytetrafluoroethylene container made of PTFE with a lid, and after keeping at 100 ℃ for 24 hours, the total mass M of ammonia ions contained in the aqueous solution from which the solid content was removed by filtration was determined by ion chromatography_cBy M_cDividing by the mass of the phosphor powder to obtain C_c。

4. The phosphor powder of any of claims 1 to 3, wherein the alpha sialon phosphor particles are formed of a compound represented by the general formula: (M1_x，M2_y，Eu_z)(Si _12－(m+n)Al _m+n)(O_nN _16－n) The Eu-containing alpha-sialon phosphor is represented by the general formula, wherein M1 is a 1-valent Li element, M2 is a 2-valent Ca element, x is 0. ltoreq. x.ltoreq.2.0, y is 0. ltoreq. y.ltoreq.2.0, z is 0. ltoreq. z.ltoreq.0.5, x + y is 0. ltoreq. x.ltoreq.0, x + y + z is 0.3. ltoreq. x.ltoreq.2.0, M is 0. ltoreq. m.ltoreq.4.0, and n is 0. ltoreq. n.ltoreq.3.0.

5. The phosphor powder of claim 4, wherein 1.5 < x + y + z ≦ 2.0.

6. The phosphor powder according to claim 4 or 5, wherein 0. ltoreq. x.ltoreq.0.1.

7. The phosphor powder according to any one of claims 1 to 6, wherein an emission peak wavelength is 590nm or more.

8. A composite comprising the phosphor powder according to any one of claims 1 to 7 and a sealing material for sealing the phosphor powder.

9. A light-emitting device comprising a light-emitting element that emits excitation light and the composite according to claim 8 that converts the wavelength of the excitation light.

Technical Field

The present invention relates to a phosphor powder, a composite, and a light-emitting device.

Background

As a nitride or oxynitride phosphor, an α -sialon phosphor obtained by activating a specific rare earth element is known to have useful fluorescence characteristics, and is applied to a white LED and the like. In the α -sialon phosphor, the Si — N bond of the α -type silicon nitride crystal is partially substituted by Al — N bond and Al — O bond, and a specific element (Ca, Li, Mg, and Y, or a lanthanoid metal excluding La and Ce) is inserted and dissolved in the crystal lattice between the crystal lattices in order to maintain the electrical neutrality. The fluorescent property is exhibited by using a part of the element which enters the solid solution as a rare earth element which becomes a luminescence center. Among them, an α -sialon phosphor obtained by dissolving Ca in a solid solution and substituting a part thereof with Eu is excited relatively efficiently in a wide wavelength region from the ultraviolet region to the cyan region, and exhibits yellow to orange emission. As an attempt to further improve the fluorescence characteristics of such an α -sialon phosphor, for example, it has been proposed to select an α -sialon phosphor having a specific average particle diameter by classification (patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2009-96882

Disclosure of Invention

In recent years, further improvement in luminance of white LEDs has been strongly desired, and further improvement in light emission characteristics of phosphor powders used for white LEDs has been also required.

In view of the above problems, an object of the present invention is to provide a phosphor powder having improved emission characteristics.

According to the present invention, there is provided a phosphor powder comprising Eu-containing α -type sialon phosphor particles, wherein the concentration C of ammonia ions in the phosphor powder is determined by the following extracted ion analysis A_A15ppm to 100 ppm.

(extracted ion analysis A)

0.5g of phosphor powder was added to 25ml of distilled water in a container made of PTFE (polytetrafluoroethylene) with a lid, and after keeping at 60 ℃ for 24 hours, the total mass M of ammonia ions contained in the aqueous solution from which the solid content was removed by filtration was determined by ion chromatography_A. Then, with M_ADividing by the mass of the phosphor powder to obtain C_A。

Further, according to the present invention, there is provided a composite comprising the above phosphor powder and a sealing material for sealing the phosphor powder.

Further, according to the present invention, there is provided a light-emitting device including a light-emitting element that emits excitation light and the complex that converts the wavelength of the excitation light.

Effects of the invention

According to the present invention, a technique relating to a phosphor powder having improved light emission characteristics can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view showing a structure of a light-emitting device according to an embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

The phosphor powder according to the embodiment is a phosphor powder composed of Eu-containing α -type sialon phosphor particles. The concentration C of ammonia ions in the phosphor powder was determined by the following extracted ion analysis A_A15ppm to 100 ppm.

(extracted ion analysis A)

0.5g of phosphor powder was charged into 25ml of distilled water in a PTFE (polytetrafluoroethylene) container with a lid, and after keeping at 60 ℃ for 24 hours, the total mass M of ammonia ions contained in the aqueous solution from which the solid content was removed by filtration was determined by ion chromatography_A. Then, with M_ADividing by the mass of the phosphor powder to obtain C_A. I.e. C_AIs an index indicating the amount of ammonia ions per unit mass of the phosphor powder (solid state).

If supplementary stated, M_AThe ammonia ion concentration of the aqueous solution measured by ion chromatography can be multiplied by the mass (25g) of water used.

In addition, C_ABy using M_ADivided by the mass (0.5g) of the phosphor powder to be analyzed.

At M_AIn the case where the unit of (b) is "g (g)", C_A[ unit: ppm of]Can be obtained by using M_A[ unit: g]The value obtained by dividing the mass of the phosphor powder (0.5g) by 10⁶And then the result is obtained.

The above supplementary matters are the same in the following extracted ion analyses B and C, except for the extraction conditions.

According to the phosphor powder of the present embodiment, the fluorescence characteristics of conventional α -sialon phosphor particles can be improved while maintaining the excitation wavelength region and the fluorescence wavelength region. Therefore, as a result, the light emitting characteristics of the light emitting device using the phosphor powder of the present embodiment can be improved.

For this reason, the detailed mechanism is not yet established, but it is considered that the concentration C of the ammonia ions in the phosphor powder obtained by the extracted ion analysis A is_AIn the phosphor powder of 15ppm to 100ppm, the surface of the α -sialon phosphor particle has high chemical stability, and the mother crystal of the phosphor contributing to fluorescence stably exists, whereby the fluorescence of the α -sialon phosphor particleThe characteristics are improved.

Thus, the concentration C of the ammonium ions in the phosphor powder obtained by the extracted ion analysis A was measured_AIn the above range, it is effective to improve the chemical stability of the surface of the α -sialon phosphor particle, and to appropriately adjust the conditions of the acid treatment step described later, for example.

(alpha-sialon phosphor particle)

The α -type sialon phosphor particles containing Eu are composed of an α -type sialon phosphor described below.

The alpha-sialon phosphor is of the general formula: (M1_x，M2_y，Eu_z)(Si_12－(m+n)Al_m+n)(O_nN_16－n) (wherein M1 is a 1-valent Li element, and M2 is 1 or more 2-valent elements selected from Mg, Ca and lanthanides (excluding La and Ce)).

The solid solution composition of the alpha-sialon phosphor is represented by x, y, z of the above general formula and m and N determined by the Si/Al ratio and O/N ratio accompanying them, 0. ltoreq. x < 2.0, 0. ltoreq. y < 2.0, 0. ltoreq. z < 0.5, 0. ltoreq. x + y, 0.3. ltoreq. x + y + z < 2.0, 0. ltoreq. m.ltoreq.4.0, 0. ltoreq. n.ltoreq.3.0.

In particular, when Ca is used as M2, the α -sialon phosphor is stabilized in a wide composition range, and a part of it is substituted with Eu, which is an emission center, and excited by light in a wide wavelength range from ultraviolet to cyan, thereby obtaining a phosphor exhibiting visible light emission of yellow to orange.

In addition, from the viewpoint of obtaining light of a bulb color in illumination applications, the α -sialon phosphor preferably does not contain Li as a solid solution composition or contains a small amount of Li. In the above general formula, it is preferable that 0. ltoreq. x.ltoreq.0.1. And/or the ratio of Li in the α -sialon phosphor particles is preferably 0% to 1% by mass.

In general, an α -type sialon phosphor has a second crystal phase different from that of the α -type sialon phosphor and an amorphous phase inevitably present, and therefore, a solid solution composition cannot be strictly defined by composition analysis or the like. The α -sialon phosphor is preferably an α -sialon single phase as a crystal phase, and aluminum nitride or a polytype thereof may be contained as another crystal phase.

In the α -type sialon phosphor particles, a plurality of equiaxed primary particles are sintered to form massive secondary particles. The primary particles in the present embodiment are the smallest particles that can exist alone and can be observed by an electron microscope or the like. The shape of the α -sialon phosphor particles is not particularly limited, and examples thereof include spherical, cubic, columnar, and amorphous shapes.

The lower limit of the average particle diameter of the α -sialon phosphor particles is preferably 1 μm or more, more preferably 5 μm or more, and still more preferably 10 μm or more. The upper limit of the average particle diameter of the α -sialon phosphor particles is preferably 30 μm or less, and more preferably 20 μm or less. The average particle diameter of the α -sialon phosphor particles is the size of the secondary particles. The transparency of the composite described later can be further improved by making the average particle diameter of the α -sialon phosphor particles to be 5 μm or more. On the other hand, by setting the average particle diameter of the α -sialon phosphor particles to 30 μm or less, generation of chips can be suppressed when the composite is cut and processed by a pelletizer or the like.

Here, the average particle size of the α -sialon phosphor particles is defined as follows based on JIS R1629: 1997 median particle diameter (D) in volume-based cumulative fraction by laser diffraction scattering₅₀)。

The phosphor powder of the present embodiment has a concentration C of ammonia ions in the phosphor powder, which is obtained by the following extracted ion analysis A_A15ppm to 100 ppm.

(extracted ion analysis A)

0.5g of phosphor powder was added to 25ml of distilled water in a container made of PTFE (polytetrafluoroethylene) with a lid, and after keeping at 60 ℃ for 24 hours, the total mass M of ammonia ions contained in the aqueous solution from which the solid content was removed by filtration was determined by ion chromatography_A. Then, with M_AThe mass (0.5g) of the phosphor powder was divided to obtain C_A。

The concentration C of the ammonium ion in the phosphor powder obtained by the above-mentioned extracted ion analysis A_AIf the amount is less than 15ppm, the amount may not be stably obtainedTo a high light emitting characteristic. The reason is not necessarily clear, and it is presumed that the reason is C_AIf the amount is less than 15ppm, a protective film is formed thickly on the surface of the α -sialon phosphor particles, and as a result, the protective film absorbs the light emitted from the phosphor, thereby lowering the internal quantum efficiency.

Concentration C of ammonia ions in phosphor powder, obtained by the extracted ion analysis A_AThe upper limit of (B) is more preferably 80ppm or less, and still more preferably 60ppm or less. By mixing C_AThe upper limit of (a) is set to the above range, whereby the α -sialon phosphor particles can be formed with suppressed reactivity with moisture.

The phosphor powder of the present embodiment is measured by the extracted ion analysis A, and the concentration C of the ammonia ions in the phosphor powder is determined_AIn addition to the above range, the concentration C of the ammonia ions in the phosphor powder is determined by the following extracted ion analysis B_BThe lower limit of (B) is preferably 50ppm or more, more preferably 60ppm or more, and still more preferably 70ppm or more. The concentration C of ammonia ions in the phosphor powder, which was obtained by the following extracted ion analysis B_BThe upper limit of (B) is preferably 250ppm or less, more preferably 200ppm or less, and still more preferably 150ppm or less.

(extracted ion analysis B)

0.5g of phosphor powder was added to 25ml of distilled water in a container made of PTFE (polytetrafluoroethylene) with a lid, and after keeping at 80 ℃ for 24 hours, the total mass M of ammonia ions contained in the aqueous solution from which the solid content was removed by filtration was determined by ion chromatography_B. Then, with M_BThe mass (0.5g) of the phosphor powder was divided to obtain C_B。

The concentration C of ammonia ions in the phosphor powder obtained by the extracted ion analysis B_BThe lower limit of (b) is set to the above range, so that high light emission characteristics can be obtained more stably.

The concentration C of the ammonium ions in the phosphor powder obtained by the extracted ion analysis B is measured_BThe upper limit of (a) is set to the above range, thereby forming the α -sialon phosphor particles in which the reactivity with moisture is further suppressed.

Further, the concentration C of the ammonia ions in the phosphor powder, which is obtained by the following extracted ion analysis C, of the phosphor powder of the present embodiment_cThe lower limit of (B) is preferably 250ppm or more, more preferably 300ppm or more, and still more preferably 350ppm or more. The concentration C of the ammonium ions in the phosphor powder was determined by the following extracted ion analysis C_cThe upper limit of (B) is preferably 650ppm or less, more preferably 630ppm or less, and still more preferably 600ppm or less.

(extracted ion analysis C)

0.5g of phosphor powder was charged into 25ml of distilled water in a PTFE (polytetrafluoroethylene) container with a lid, and after keeping at 100 ℃ for 24 hours, the total mass M of ammonia ions contained in the aqueous solution from which the solid content was removed by filtration was determined by ion chromatography_c. Then, with M_cThe mass (0.5g) of the phosphor powder was divided to obtain C_c。

The concentration C of ammonia ions in the phosphor powder obtained by the extracted ion analysis C is measured_cThe lower limit of (2) is set to the above range, and high external quantum efficiency can be obtained more stably.

The concentration C of the ammonia ions in the phosphor powder obtained by the extracted ion analysis C_cThe upper limit of (a) is set to the above range, whereby the α -sialon phosphor particles can be formed with further suppressed reactivity with moisture.

The concentration C of the ammonia ions in the phosphor powder measured by the extracted ion analysis A is determined from the phosphor powder described above_AThe amount is 15ppm to 100ppm, and the improvement of the fluorescence characteristic can be achieved.

(method for producing phosphor powder)

A method for producing a phosphor powder composed of α -sialon phosphor particles according to this embodiment will be described. In the α -sialon phosphor particles, a part of the raw material powder mainly reacts during the synthesis process to form a liquid phase, and each element moves through the liquid phase, whereby solid solution formation and particle growth proceed.

First, raw materials containing elements constituting the Eu-containing α -type sialon phosphor particles are mixed. In alpha-sialon phosphor particles synthesized using calcium nitride as a calcium raw material and having a low oxygen content, calcium is dissolved in a high concentration. In particular, when the Ca solid solution concentration is high, a phosphor having an emission peak wavelength on a higher wavelength side (590nm or more, more specifically, 590nm to 610nm, and even more specifically, 592nm to 608nm) than a conventional composition using an oxide raw material can be obtained. Specifically, in the above general formula, 1.5 < x + y + z.ltoreq.2.0 is preferable. The fine adjustment of the emission spectrum may be performed by substituting a part of Ca for Li, Mg, Sr, Ba, Y, and lanthanoid (excluding La and Ce).

Examples of the raw material powder other than the above include silicon nitride, aluminum nitride, and Eu compound. Examples of the Eu compound include europium oxide, a compound which becomes europium oxide after heating, and europium nitride. Europium nitride is preferred for reducing the amount of oxygen in the system.

When a proper amount of α -sialon phosphor particles synthesized in advance is added to the raw material powder, α -sialon phosphor particles having a relatively large minor axis diameter can be obtained as a starting point of particle growth, and the particle shape can be controlled by changing the form of the added α -sialon particles.

As a method of mixing the above-mentioned raw materials, there are a dry mixing method, and a method of wet mixing in an inert solvent which does not substantially react with each component of the raw materials, and then removing the solvent. Examples of the mixing device include a V-type mixer, a swing type mixer, a ball mill, and a vibration mill. Mixing of calcium nitride, which is unstable in the atmosphere, is performed in a glove box in an inert atmosphere because hydrolysis and oxidation thereof affect the characteristics of the synthetic product.

The mixed powder (hereinafter, simply referred to as "raw material powder") is filled in a container made of a material having low reactivity with the raw material and the synthesized phosphor, for example, a container made of boron nitride. Subsequently, the mixture was heated in a nitrogen atmosphere for a predetermined time. Thus, an α -sialon phosphor was obtained. The temperature of the heat treatment is preferably 1650 ℃ to 1950 ℃.

By setting the temperature of the heat treatment to 1650 ℃ or higher, the amount of unreacted product remaining can be suppressed, and primary particles can be sufficiently grown. Further, by setting 1950 ℃ or lower, significant sintering between particles can be suppressed.

From the viewpoint of suppressing sintering between particles during heating, the raw material powder is preferably filled into the container in an increased volume. Specifically, when a container is filled with the raw material powder, the bulk density is preferably set to 0.6g/cm³The following.

The heating time in the heat treatment is preferably 2 to 24 hours, as a time range in which a large amount of unreacted materials, insufficient primary particle growth, or sintering between particles does not occur.

The above-described steps produce an α -sialon phosphor having an ingot-like outer shape. The secondary particles of the alpha-sialon phosphor are adjusted to obtain D having secondary particles adjusted by a pulverizing step using a pulverizer such as a crusher, mortar mill, ball mill, vibration mill or jet mill, and a classifying step after the pulverizing step₅₀A phosphor powder comprising α -sialon phosphor particles having a particle diameter. Further, by performing the step of dispersing the dispersion in an aqueous solution to remove secondary particles having a small particle diameter and being less likely to settle, D of the secondary particles can be adjusted₅₀And (4) the particle size.

The phosphor powder composed of α -sialon phosphor particles according to the embodiment can be produced by performing the above-described steps and then performing an acid treatment step.

In the acid treatment step, for example, α -sialon phosphor particles are immersed in an acidic aqueous solution. Examples of the acidic aqueous solution include an acidic aqueous solution containing 1 acid selected from hydrofluoric acid, nitric acid, hydrochloric acid, and the like, and a mixed acid aqueous solution obtained by mixing 2 or more of the above acids. Among these, a hydrofluoric acid aqueous solution containing hydrofluoric acid alone and a mixed acid aqueous solution obtained by mixing hydrofluoric acid and nitric acid are more preferable. The stock solution concentration of the acidic aqueous solution is appropriately set according to the strength of the acid used, and is, for example, preferably 0.7% to 100%, more preferably 0.7% to 40%. The temperature at the time of the acid treatment is preferably 60 to 90 ℃, and the reaction time (immersion time) is preferably 15 to 80 minutes.

A preferred embodiment of the acid treatment step is a method in which the phosphor powder is added to an acidic solution and then stirred for a predetermined time. Thus, the reaction with the acid can be more reliably performed on the surface of the α -sialon phosphor particles. By stirring at a high speed, the acid treatment of the particle surface can be easily and sufficiently performed. The "high speed" here also depends on the stirring apparatus used, but when a laboratory-grade magnetic stirrer is used, the stirring speed is, for example, 400rpm or more, and in reality, 400rpm to 500 rpm. If the stirring speed is about 200rpm for the purpose of ordinary stirring in which new acid is continuously supplied to the particle surface, it is easy to sufficiently treat the particle surface by physical action in addition to chemical action by performing high-speed stirring at 400rpm or more.

As described above, the concentration C of the ammonia ions in the phosphor powder to be measured by the extracted ion analysis A_AThe concentration of the acidic aqueous solution used for the acid treatment can be controlled to be 15ppm to 100ppm by optimally adjusting the stock solution concentration, the temperature during the acid treatment, the reaction time, the stirring speed, and the like. For example, with reference to the examples described later, the concentration C of the ammonia ion measured by the extracted ion analysis A can be adjusted by performing the acid treatment under conditions similar to the combination of the stock solution concentration of the acidic aqueous solution, the temperature at the time of the acid treatment, the reaction time, and the stirring speed_ASet to a desired value.

(Complex)

The composite according to the embodiment includes the phosphor particles and a sealing material for sealing the phosphor particles. In the composite according to the present embodiment, a plurality of the phosphor particles are dispersed in the sealing material. As the sealing material, known materials such as resin, glass, and ceramics can be used. Examples of the resin used for the sealing material include transparent resins such as silicone resin, epoxy resin, and urethane resin.

Examples of the method for producing the composite include the following methods: the phosphor particles of the present embodiment are prepared by adding a powder composed of α -sialon phosphor particles to a liquid resin or a powdery glass or ceramic, uniformly mixing the mixture, and then curing or sintering the mixture by heat treatment.

(light-emitting device)

Fig. 1 is a schematic cross-sectional view showing a structure of a light-emitting device according to an embodiment. As shown in fig. 1, the light-emitting device 100 includes a light-emitting element 120, a heat sink 130, a case 140, a first lead frame 150, a second lead frame 160, a bonding wire 170, a bonding wire 172, and a composite 40.

The light emitting element 120 is mounted on a predetermined region of the upper surface of the heat sink 130. By mounting the light emitting element 120 on the heat sink 130, the heat dissipation of the light emitting element 120 can be improved. In addition, a substrate for package may be used instead of the heat sink 130.

The light emitting element 120 is a semiconductor element that emits excitation light. As the light emitting element 120, for example, an LED chip that generates light having a wavelength of 300nm to 500nm corresponding to light from near ultraviolet to cyan can be used. One electrode (not shown) disposed on the upper surface side of the light-emitting element 120 is connected to the surface of the first lead frame 150 via a bonding wire 170 such as a gold wire. The other electrode (not shown) formed on the upper surface of the light-emitting element 120 is connected to the surface of the second lead frame 160 via a bonding wire 172 such as a gold wire.

The housing 140 is formed with a substantially funnel-shaped recess portion whose aperture gradually increases from the bottom surface upward. The light emitting element 120 is provided on the bottom surface of the recess. The wall surface surrounding the recess of the light emitting element 120 functions as a reflection plate.

The composite 40 is filled in the recess formed in the wall surface by the case 140. The composite 40 is a wavelength conversion member that converts excitation light emitted from the light emitting element 120 into light of a longer wavelength. As the composite 40, the composite of the present embodiment is used, and the α -type sialon phosphor particles 1 of the present embodiment are dispersed in a sealing material 30 such as a resin. The light-emitting device 100 emits a mixed color of light from the light-emitting element 120 and light generated from the α -type sialon phosphor particles 1 excited by absorbing the light from the light-emitting element 120. The light-emitting device 100 preferably emits white light by mixing the light of the light-emitting element 120 and the light generated from the α -sialon phosphor particles 1.

In the light-emitting device 100 of the present embodiment, as described above, the phosphor powder composed of the α -sialon phosphor particles 1 satisfies the concentration C of ammonia ions in the phosphor powder obtained by the extracted ion analysis a under the above conditions_AThe condition of 15ppm to 100ppm improves the fluorescence characteristics of the α -sialon phosphor particles 1 and the composite 40, and further improves the emission intensity of the light-emitting device 100.

Fig. 1 illustrates a surface-mount light-emitting device, but the light-emitting device is not limited to the surface-mount type. The light emitting device may be a shell type, a COB (chip on board) type, a CSP (chip scale package) type.

While the embodiments of the present invention have been described above, these are merely illustrative of the present invention, and various configurations other than the above-described configurations may be adopted.

Examples

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto.

(example 1)

The raw material powders were mixed by dry blending 62.4 parts by mass of silicon nitride powder (manufactured by yukexing corporation, E10 grade), 22.5 parts by mass of aluminum nitride powder (manufactured by TOKUYAMA corporation, E grade), 2.2 parts by mass of europium oxide powder (manufactured by shin-Etsu chemical Co., Ltd., RU grade) and 12.9 parts by mass of calcium nitride powder (manufactured by high purity chemical research Co., Ltd.) in a glove box, and then the resultant mixture was sieved with a nylon mesh of 250 μm to obtain a raw material mixed powder. 120g of this raw material mixed powder was charged into a cylindrical boron nitride container (N-1 grade, manufactured by electrochemical Co., Ltd.) with a lid having an internal volume of 0.4 liter.

The raw material mixed powder was subjected to a heating treatment for 16 hours at 1800 ℃ in a nitrogen atmosphere of atmospheric pressure in an electric furnace of a carbon heater together with a vessel. Since calcium nitride contained in the raw material mixed powder is easily hydrolyzed in air, the boron nitride container filled with the raw material mixed powder is taken out from the glove box, and then immediately set in an electric furnace, and vacuum evacuation is performed to prevent the reaction of calcium nitride.

The resultant was lightly crushed with a mortar, and the whole was passed through a sieve having a mesh size of 150 μm to obtain a phosphor powder. The phosphor powder was examined for the crystal phase by powder X-ray Diffraction (hereinafter, referred to as XRD measurement) using CuK α rays, and as a result, the crystal phase existing was Ca — α sialon (Ca-containing α sialon) containing Eu element.

Then, 3.2ml of 50% hydrofluoric acid and 0.8ml of 70% nitric acid were mixed to prepare a mixed stock solution. 396ml of distilled water was added to the mixed stock solution, and the concentration of the mixed stock solution was diluted to 1.0% to prepare 400ml of a mixed acid aqueous solution. 30g of the phosphor powder composed of the α -sialon phosphor particles described above was added to this mixed acid aqueous solution, and the mixture was immersed in a 500ml beaker for 30 minutes while being stirred at a rotation speed of 450rpm with a magnetic stirrer, with the temperature of the mixed acid aqueous solution being maintained at 80 ℃. The acid-treated powder was thoroughly washed with distilled water and filtered, and then dried, and then passed through a sieve having a mesh size of 45 μm to prepare phosphor powder composed of α -type sialon phosphor particles of example 1.

(example 2)

Phosphor powder composed of α -type sialon phosphor particles of example 2 was prepared in the same manner as in example 1 except that 396ml of distilled water was added to a mixed stock solution obtained by mixing 2.0ml of 50% hydrofluoric acid and 2.0ml of 70% nitric acid instead of the mixed acid aqueous solution used in example 1 to prepare a mixed acid aqueous solution having a stock solution concentration of 1.0%.

(example 3)

Phosphor powder composed of α -type sialon phosphor particles of example 3 was prepared in the same manner as in example 1 except that 396ml of distilled water was added to a mixed stock solution obtained by mixing 1.2ml of 50% hydrofluoric acid and 2.8ml of 70% nitric acid instead of the mixed acid aqueous solution used in example 1 to prepare a mixed acid aqueous solution having a stock solution concentration of 1.0%.

(example 4)

A phosphor powder composed of α -type sialon phosphor particles of example 4 was prepared in the same manner as in example 1 except that 300ml of distilled water was added to a mixed stock solution obtained by mixing 50ml of 50% hydrofluoric acid and 50ml of 70% nitric acid instead of the mixed acid aqueous solution used in example 1 to prepare a 25% stock solution mixed acid aqueous solution, and the phosphor powder was immersed for 60 minutes while maintaining the temperature of the mixed acid aqueous solution at 80 ℃.

Comparative example 1

A phosphor powder composed of α -type sialon phosphor particles of comparative example 1 was prepared by the same procedure as in example 1 except that a mixed acid aqueous solution having a stock solution concentration of 0.5% obtained by mixing 398ml of distilled water with a mixed stock solution obtained by mixing 1.0ml of 50% hydrofluoric acid and 1.0ml of 70% nitric acid was used instead of the mixed acid aqueous solution used in example 1, and the mixed acid aqueous solution was immersed for 30 minutes in a 500ml beaker while keeping the temperature of the mixed acid aqueous solution at 80 ℃ and stirring the mixed acid aqueous solution at a rotation speed of 300rpm using a magnetic stirrer.

The stock solution concentration and the stirring rotation speed of the mixed acid aqueous solution used in comparative example 1 were set to conventional levels.

Comparative example 2

Phosphor powder composed of α -type sialon phosphor particles was produced in the same manner as in example 3, except that the stirring speed by the magnetic stirrer was changed from 450rpm to 200rpm, which is a normal level, in example 3.

(measurement of particle size)

Particle size using Microtrac MT3300EX II (Microtrac BEL co., ltd.) and a particle size calculated according to JIS R1629: 1997 by laser diffraction and scattering. 0.5g of phosphor powder was put into 100cc of ion-exchanged water, and dispersed for 3 minutes by Ultrasonic Homogenizer US-150E (manufactured by Nippon Seiko Co., Ltd., chip size. phi.20, Amplitude 100%, oscillation frequency 19.5KHz, Amplitude about 31 μm), and thereafter, the particle size was measured by MT3300EX II. Determining the median particle diameter (D) from the particle size distribution obtained₅₀)。

(extracted ion analysis A)

0.5g of phosphor powder was put into 25ml of distilled water in a PTFE container with a lid. A container containing phosphor powder and distilled waterAfter being maintained at 60 ℃ for 24 hours, the solid content was removed by filtration. The concentration of ammonia ions in the aqueous solution from which the solid components were removed was measured by an ion chromatography apparatus (manufactured by Thermo Fisher Scientific Co., Ltd.), and the total mass M of eluted ammonia ions was determined from the concentration and the amount of the aqueous solution_A(unit: g). Then, with M_ADivided by the mass of phosphor powder (0.5g), multiplied by 10⁶Thereby obtaining the concentration C of the ammonium ion in the phosphor powder_A(unit: ppm).

(extracted ion analysis B)

0.5g of phosphor powder was put into 25ml of distilled water in a PTFE container with a lid. The vessel containing the phosphor powder and distilled water was kept at 80 ℃ for 24 hours, and then the solid content was removed by filtration. The concentration of ammonia ions in the aqueous solution from which the solid components were removed was measured by an ion chromatography apparatus (manufactured by Thermo Fisher Scientific Co., Ltd.), and the total mass M of eluted ammonia ions was determined from the concentration and the amount of the aqueous solution_B(unit: g). Then, with M_BDivided by the mass of phosphor powder (0.5g), multiplied by 10⁶Thereby obtaining the concentration C of the ammonium ion in the phosphor powder_B(unit: ppm).

(extracted ion analysis C)

0.5g of phosphor powder was put into 25ml of distilled water in a PTFE container with a lid. The vessel containing the phosphor powder and distilled water was kept at 100 ℃ for 24 hours, and then the solid content was removed by filtration. The concentration of ammonia ions in the aqueous solution from which the solid components were removed was measured by an ion chromatography apparatus (manufactured by Thermo Fisher Scientific Co., Ltd.), and the total mass M of dissolved ammonia ions was determined from the concentration and the amount of the aqueous solution_C(unit: g). Then, with M_CDivided by the mass of phosphor powder (0.5g), multiplied by 10⁶Thereby obtaining the concentration C of the ammonium ion in the phosphor powder_C(unit: ppm).

(luminescent Property)

The internal quantum efficiency and the external quantum efficiency at room temperature of each of the obtained phosphor powders were measured by a spectrophotometer (MCPD-7000, manufactured by Otsuka electronics Co., Ltd.), and the calculation was performed according to the following procedure.

The concave cuvette was filled with phosphor powder so that the surface thereof was smooth, and an integrating sphere was attached. Monochromatic light split from a light emitting source (Xe lamp) into 455nm wavelength is introduced into the integrating sphere using an optical fiber. The sample of the phosphor powder is irradiated with the monochromatic light as an excitation source, and the fluorescence spectrum of the sample is measured.

A standard reflecting plate (SPECTRALON manufactured by Labsphere) having a reflectance of 99% was attached to the sample portion, and the spectrum of excitation light having a wavelength of 455nm was measured. At this time, the number of excitation light photons is calculated from the spectrum in the wavelength range of 450nm to 465nm (Qex).

Phosphor powder composed of α -type sialon phosphor particles was attached to the sample portion, and the number of photons of excitation reflected light (Qref) and the number of photons of fluorescence (Qem) were calculated. The number of photons of the excitation reflected light is calculated in the same wavelength range as the number of photons of the excitation light, and the number of photons of the fluorescence is calculated in the range of 465nm to 800 nm.

Internal quantum efficiency (Qem/(Qex-Qref)) × 100

External quantum efficiency (Qem/Qex). times.100

When the standard sample NSG1301 sold by Sialon corporation was measured by the above-mentioned measurement method, the external quantum efficiency was 55.6% and the internal quantum efficiency was 74.8%. The apparatus was calibrated using this sample as a standard.

The peak wavelengths of the emission spectra of the phosphor powders obtained by the above measurement (excitation light wavelength: 455nm) were all 600nm (large wavelength) in examples 1 to 4.

[ Table 1]

As shown in Table 1, the concentration C of ammonia ions was confirmed in the phosphor powder after the phosphor powder was held at 60 ℃ for 24 hours_AThe phosphor powders of examples 1 to 4 in the range of 15ppm to 100ppm exhibited improved internal and external quantum efficiencies and excellent light emission characteristics as compared with comparative examples 1 and 2 which did not satisfy the above conditions.

In addition, theFor example, as can be understood from a comparison of example 3 and comparative example 2: even if the same raw materials are used, if the stirring speed in the acid treatment is small, C is not easily obtained_APhosphor powder in the range of 15ppm to 100 ppm.

The present application claims priority based on Japanese application laid-open application No. 2019-069107 applied on 29/3/2019 and Japanese application laid-open application No. 2020-002550 applied on 10/1/2020, the entire disclosures of which are incorporated herein by reference.

Description of the symbols

1 alpha-sialon phosphor particle

30 sealing Material

40 composite body

100 light emitting device

120 light emitting element

130 heat sink

140 casing

150 first lead frame

160 second lead frame

170 bonding wire

172 join line