β-type sialon phosphor particles

Abstract

This invention provides β-type sialon phosphor particles with excellent luminescence properties. [Solution] The β-type Sialon phosphor particles of the present invention have a particle size (D50) at which the cumulative volume frequency of the particle size distribution measured by wet laser diffraction particle size distribution method is 5 to 150 μm, and satisfy the following condition i: (Condition i) When the surface of the β-type Sialon phosphor particles is observed at a magnification of 50,000x using a scanning electron microscope (SEM), a striped pattern can be confirmed.

Description

[Technical Field]

[0001] The present invention relates to β-type sialon phosphor particles. More specifically, it relates to β-type sialon phosphor particles, β-type sialon phosphor powder containing said β-type sialon phosphor particles, and a light-emitting device using said β-type sialon phosphor powder. [Background technology]

[0002] Various developments have been made regarding β-type sialon phosphors. As an example of this type of technology, the technology described in Patent Document 1 is known. Patent Document 1 describes a method for producing β-sialon phosphors, in which a first heat-treated product obtained by heat-treating a composition containing aluminum, oxygen atoms, and silicon nitride containing europium is mixed with an aqueous sodium hydroxide solution, a first thermal base treatment is performed in air at 70°C for 3 hours, and a second thermal base treatment is performed in a nitrogen atmosphere at 200°C for 2 hours (Claim 1, 3, paragraph 0009, Example 6, etc. of Patent Document 1). It should be noted that the first temperature, which is the heating temperature for the first thermal base treatment, is 50°C or higher and 150°C or lower (paragraph 0051). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2017-110206 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, as a result of the inventors' investigations, it was found that the β-type sialon phosphor obtained by the manufacturing method described in Patent Document 1 above has room for improvement in terms of efficiently obtaining good luminescence characteristics. [Means for solving the problem]

[0005] The inventors investigated how to efficiently obtain higher brightness and focused on the fact that when a β-type sialon phosphor is emitted, the excitation light is reflected within the β-type sialon phosphor, reducing the efficiency of light extraction. Therefore, they hypothesized that the surface state of the β-type sialon phosphor has an effect and conducted further investigations. They found that the fringe pattern observed on the surface of a β-type sialon phosphor of a predetermined particle size using a scanning electron microscope (SEM) contributes to the suppression of light reflection. Further investigations led to the development of a new index, and it was found that by controlling light reflection using this index, a phosphor with high brightness can be efficiently realized, thus completing the present invention.

[0006] According to one aspect of the present invention, the following β-type sialon phosphor particles and related technologies are provided.

[0007] [1] β-type Sialon phosphor particles having a particle size (D50) of 50% of the cumulative volume frequency of the particle size distribution measured by wet laser diffraction particle size distribution method, where the particle size is 5 to 150 μm. Beta-type sialon phosphor particles that satisfy the following condition i. (Condition i) When the surface of the β-type Sialon phosphor particle is observed at a magnification of 50,000x using a scanning electron microscope (SEM), a striped pattern can be confirmed. [2] [1] The β-type sialon phosphor particles described above, In condition i, the striped pattern is a β-type sialon phosphor particle having high-density striped regions where the stripe density of the striped pattern is 15 stripes / μm or more in a 2.5 μm square area. [3] Beta-type sialon phosphor particles as described in [1] or [2], In condition i, the striped pattern is a β-type sialon phosphor particle having a stripe density of 15 stripes / μm or more, and the striped pattern has a linear region composed of linear stripes with a length of 1 μm or more. [4] A β-type sialon phosphor particle as described in any one of [1] to [3], In condition i, the striped pattern is a β-type sialon phosphor particle in which the stripe density of the striped pattern is 15 stripes / μm or more in a 2.5 μm square area, and the striped pattern has a curved region composed of curved stripes. [5] [1] to [4] A β-type sialon phosphor particle described in any one of the above, In condition i, the striped pattern is a β-type sialon phosphor particle having a medium-density striped region where the stripe density of the striped pattern in a 2.5 μm square area is 5 stripes / μm or more and less than 15 stripes / μm. [6] [1] to [5] A β-type sialon phosphor particle as described in any one of the above, Furthermore, β-type sialon phosphor particles that satisfy condition ii. (Condition ii) When the surface of the β-type Sialon phosphor particle is observed with a scanning electron microscope (SEM) at a magnification of 50,000x, no smooth area of ​​2.5 μm square or larger is observed. A β-type sialon phosphor powder containing β-type sialon phosphor particles as described in any one of [7][1] to [6]. [8] A light-emitting device including a light-emitting source and a wavelength conversion member, The wavelength conversion member includes phosphor powder, The phosphor powder is a light-emitting device containing the β-type sialon phosphor powder described in [7]. [9] [8] The light-emitting device described above, The light-emitting device includes an LED chip that generates light with a wavelength of 300 nm to 500 nm. [Effects of the Invention]

[0008] According to the present invention, β-type sialon phosphor particles capable of improving luminescence characteristics, and related technologies are provided. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an image of β-type Sialon phosphor particles observed using a scanning electron microscope (SEM). [Figure 2]It is a figure showing a scanning electron microscope (SEM) image of the β - sialon phosphor particles of Example 1. [Figure 3] It is a figure showing a scanning electron microscope (SEM) image of the β - sialon phosphor particles of Example 2. [Figure 4] It is a figure showing a scanning electron microscope (SEM) image of the β - sialon phosphor particles of Example 3. [Figure 5] It is a figure showing a scanning electron microscope (SEM) image of the β - sialon phosphor particles of Comparative Example 1.

Modes for Carrying Out the Invention

[0010] <β - sialon phosphor particles> The β - sialon phosphor particles of this embodiment have a particle size (D50) of 5 - 150 μm at the cumulative volume frequency of 50% of the particle size distribution measured by the wet laser diffraction particle size distribution method and satisfy the following condition i.

[0011] (Condition i) When the surface of the β - sialon phosphor particles is observed with a scanning electron microscope (SEM) at a magnification of 50,000 times, a striped pattern can be confirmed.

[0012] The inventor devised condition i in order to highly control the light reflection state on the surface of β - sialon phosphor particles having a specific particle size. By making the β - sialon phosphor particles satisfy condition i, it was found that the luminance can be improved while reducing the amount of phosphor. Thus, the present invention was completed. That is, conventionally, when a β - sialon phosphor emits light, the light emitted within the β - sialon phosphor is reflected, and the light extraction efficiency tends to decrease. In contrast, the β - sialon phosphor of this embodiment can suppress the reflection of light emitted within the β - sialon phosphor and increase the light extraction efficiency. As a result, a phosphor with high luminance can be efficiently realized.

[0013] In the above condition i, the striped pattern is observed as a pattern due to differences in density when viewed at a magnification of 50,000x using a scanning electron microscope (SEM), and may be due to the shape of the surface of the β-type sialon phosphor particles. Specifically, it is preferable that the striped pattern is composed of wrinkles, grooves, steps, irregularities, etc. on the surface of the β-type sialon phosphor particles. Furthermore, the striped pattern only needs to be observed on a portion of the surface of the β-type sialon phosphor particles, and does not need to cover the entire surface of the β-type sialon phosphor particles. Also, the spacing and length of the stripes are not particularly limited and may be irregular. The shape of the stripes is also not particularly limited and may be linear, a combination of curves and lines, or an irregular pattern.

[0014] For example, Figure 1 is a diagram showing an image of β-type Sialon phosphor particles observed using a scanning electron microscope (SEM). Figure 1 shows examples of high-density regions, medium-density regions, and linear regions, which will be described later. However, Figure 1 is an illustrative diagram and is not directly related to the present invention.

[0015] In condition i, it is preferable that the striped pattern has high-density striped regions where the stripe density of the striped pattern is 15 stripes / μm or more in a 2.5 μm square area. This makes it easier to improve the luminescence characteristics.

[0016] In condition i, it is preferable that the striped pattern has a medium-density striped region where the stripe density of the striped pattern in a 2.5 μm square area is 5 stripes / μm or more and less than 15 stripes / μm. This makes it easier to improve the luminescence characteristics.

[0017] In condition i, it is preferable that the striped pattern has a stripe density of 15 stripes / μm or more, and that the striped pattern has a linear region composed of linear stripes with a length of 1 μm or more. That is, it is preferable that the pattern has a region in which linear stripes with a length of 1 μm or more are arranged at a stripe density of 15 stripes / μm or more. This makes it easier to improve the luminescence characteristics. Furthermore, in the linear region, it is preferable that adjacent stripes are approximately parallel to each other.

[0018] In condition i, it is preferable that the striped pattern has a stripe density of 15 stripes / μm or more in a 2.5 μm square area, and that the striped pattern has a curved region composed of curved stripes. That is, it is preferable that there is a region in which curved stripes are arranged at a stripe density of 15 stripes / μm or more. This makes it easier to improve the luminescence characteristics. Furthermore, in the curved region, it is preferable that adjacent stripes are approximately parallel to each other.

[0019] The β-type Sialon phosphor particles of this embodiment preferably further satisfy condition ii. This prevents light converted within the β-type sialon phosphor particles from being reflected off the particle surface and remaining inside, thereby increasing brightness more efficiently.

[0020] (Condition ii) When the surface of the β-type Sialon phosphor particle is observed with a scanning electron microscope (SEM) at a magnification of 50,000x, no smooth area of ​​2.5 μm square or larger is observed.

[0021] In other words, condition ii means that when the surface of the β-type Sialon phosphor particles is observed in 2.5 μm square areas at a magnification of 50,000x using a scanning electron microscope (SEM), there are no smooth areas where no stripe pattern is observed throughout the entire 2.5 μm square area, and some kind of stripe pattern is observed. Furthermore, the shape of the smooth areas is not particularly limited.

[0022] Beta-type sialon phosphor particles that satisfy conditions i and ii above can be realized, for example, by appropriately selecting the types and amounts of each component contained in the beta-type sialon phosphor, the particle size of the beta-type sialon phosphor, and the method of preparing the beta-type sialon phosphor. Among these, for example, controlling the conditions of firing and annealing (crystal growth) of the beta-type sialon phosphor, and the acid treatment conditions can create wrinkles or grooves by removing unwanted materials. In particular, controlling the temperature at which gas is introduced during the annealing process is effective. The specifics will be explained later in the section on the method of producing beta-type sialon phosphor.

[0023] [Particle size] The β-type Sialon phosphor particles of this embodiment have a particle size (D50) at which the cumulative volume frequency of the particle size distribution measured by wet laser diffraction particle size distribution method is 5 to 150 μm, preferably 7 μm or more, more preferably 10 μm or more, even more preferably 12 μm or more, preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less. By setting the particle size (D50) below the upper limit mentioned above, it is possible to obtain good brightness while suppressing variations in the chromaticity of the emitted color. On the other hand, by setting the particle size (D50) above the lower limit mentioned above, it becomes easier to improve brightness.

[0024] The particle size (D50) can be measured using the following procedure. (procedure) The measurement will be carried out in accordance with the method for measuring particle size distribution by laser diffraction and scattering described in JIS R 1629:1997 "Method for measuring particle size distribution of fine ceramic raw materials by laser diffraction and scattering". A particle size distribution analyzer (Microtrac MT3300EX II, manufactured by Microtrac-Bell Co., Ltd.) will be used for the measurement. First, 0.1 g of the phosphor to be measured is put into 100 mL of ion-exchanged water, and dispersion treatment is performed for 3 minutes using an ultrasonic homogenizer (manufactured by Nippon Seiki Co., Ltd., product name: "Ultrasonic Homogenizer US-150E", chip size: φ20, Amplitude: 100%, oscillation frequency: 19.5 KHz, amplitude: about 31 μm) to prepare a measurement sample. Then, the particle size is measured using a particle size distribution measuring device.

[0025] The particle size (D50) of the β-sialon phosphor particles can be controlled by known methods, for example, by adjusting the processing conditions such as grinding and classification, or by adjusting the manufacturing conditions of the β-sialon phosphor particles.

[0026] Hereinafter, other characteristics and configurations of the β-sialon phosphor particles of the present embodiment will be described.

[0027] The β-sialon phosphor particles of the present embodiment are extremely useful as phosphors for light sources such as Light Emitting Diode (hereinafter referred to as LED).

[0028] The β-sialon phosphor particles can absorb blue light in the wavelength range of 420 nm to 480 nm, for example, and emit light having a peak wavelength in the range exceeding 480 nm and not exceeding 800 nm.

[0029] The β-sialon phosphor particles are not particularly limited as long as they can be used as phosphors, but are composed of europium-activated β-sialon in which europium is dissolved.

[0030] The europium-activated β-sialon phosphor particles have the general formula Si 6-z Al z O z N 8-z :Eu 2+ (0 < z ≦ 4.2). The general formula Si 6-z Al z O z N 8-z :Eu 2+In this case, the z value and the europium content are not particularly limited, but the z value is, for example, more than 0 and 4.2 or less, and from the viewpoint of further improving the emission intensity of the europium-activated β-sialon phosphor, it is preferably 0.005 or more and 1.0 or less. Also, the content of europium in the europium-activated β-sialon phosphor particles is preferably, for example, 0.1 mass% or more and 2.0 mass% or less.

[0031] <Method for Producing β-Sialon Phosphor Particles> Next, the method for producing the β-sialon phosphor particles of the present embodiment will be described.

[0032] An example of the method for producing the β-sialon phosphor particles of the present embodiment is a mixing step of mixing raw material powders containing silicon, aluminum, an activating element, etc., a firing step of firing the mixture to obtain a fired product, and a post-treatment step such as a crushing and pulverizing treatment, a classification treatment, an annealing treatment, and an acid treatment. It includes. Hereinafter, the details of each step will be described.

[0033] [Mixing Step] Raw material powders containing silicon, aluminum, and europium are mixed by a known method.

[0034] [Firing Step] The mixture obtained by mixing is fired in an atmosphere of an inert gas or a non-oxidizing gas to produce β-sialon phosphor particles.

[0035] The above β-sialon phosphor particles have a crystal represented by the general formula Si 6-z Al z O z N 8-z :Eu(0 < z ≦ 1.0). The phosphor containing the β-sialon phosphor particles may be partially or entirely composed of the above crystal phase. General formula Si 6-z Al z O z N 8-zIn Eu, the europium content is preferably, for example, 0.1% by mass or more and 2.0% by mass or less.

[0036] The firing temperature in the firing process is preferably 1800°C to 2100°C, and more preferably 1850°C to 2050°C. By setting the firing temperature above the lower limit, the luminescence intensity can be improved. On the other hand, by setting the firing temperature below the upper limit, the thermal load can be reduced. The firing process may be carried out multiple times. Furthermore, additional raw materials may be added during the second and subsequent firings.

[0037] [Post-processing steps] The post-processing steps include one or more treatments selected from crushing and grinding, classification, annealing, and acid treatment, and these treatments can be performed in any order.

[0038] (Annealing treatment) The obtained β-type Sialon phosphor may be annealed under a gas atmosphere. The gas introduction temperature during the annealing process is preferably 300°C to 950°C, more preferably 400°C to 800°C, and even more preferably 450°C to 650°C. By setting the gas introduction temperature during annealing to above the lower limit mentioned above, crystal surface reconstruction is promoted, and good luminescence intensity is maintained. On the other hand, by keeping the gas introduction temperature during annealing below the above upper limit, fine irregularities can be introduced into the surface during the crystal surface reconstruction process. As a result, light reflection is suppressed, making it easier to improve brightness. Furthermore, the maximum temperature for the annealing process is preferably 1200°C to 1700°C, more preferably 1300°C to 1600°C, and even more preferably 1400°C to 1500°C.

[0039] The atmospheric gas used during the annealing process is selected from one of the following: noble gases of Group 18 of the periodic table such as argon, inert gases such as nitrogen, hydrogen gas, or a mixture of hydrogen and argon gases.

[0040] Annealing can be performed at a wide range of atmospheric pressures, from reduced to increased pressure, but the decomposition of β-type Sialon phosphor can be suppressed by using a pressure of 1 kPa or higher. On the other hand, since increasing the atmospheric pressure expands other conditions necessary for exhibiting the annealing effect (lower temperature, shorter processing time), the preferred atmospheric pressure is 10 MPa or less, and more preferably less than 1 MPa.

[0041] The annealing time is preferably 1 hour to 24 hours, and more preferably 2 hours to 10 hours. In particular, it is preferable to maintain an ambient temperature of 1400-1500°C during the annealing process for 8 hours.

[0042] (Acid treatment) Furthermore, after annealing, the β-type Sialon phosphor may be subjected to an acid treatment by immersing it in an acid solution. This can further improve the properties of the phosphor.

[0043] Acid treatment is preferably performed by immersing the β-type sialon phosphor in an acid solution, separating the β-type sialon phosphor from the acid using a filter or the like, and then washing the separated β-type sialon phosphor with water. Acid treatment can remove decomposition products of the β-type sialon phosphor crystals that are generated during annealing, thereby improving the fluorescence properties.

[0044] Acids used in acid treatment include hydrofluoric acid, sulfuric acid, phosphoric acid, hydrochloric acid, or nitric acid, either individually or in mixtures. A mixed acid consisting of hydrofluoric acid and nitric acid is preferred as it is suitable for removing decomposition products.

[0045] The acid concentration is preferably 5-100%, more preferably 10-50%, and even more preferably 20-30%. By setting the acid concentration above the lower limit mentioned above, it becomes easier to create fine depressions in some of the β-type Sialon phosphor particles. As a result, light reflection can be controlled to a high degree, and brightness can be increased while maintaining good luminescence intensity. On the other hand, by keeping the acid concentration below the above upper limit, good brightness can be obtained while maintaining good internal quantum efficiency.

[0046] The temperature of the acid solution during acid treatment can be at room temperature, but to enhance the effectiveness of the acid treatment, it is preferable to heat it to between 50°C and 90°C.

[0047] By the method described above, the β-type sialon phosphor particles of this embodiment can be obtained.

[0048] Furthermore, known processes may be added as needed in this embodiment. For example, post-processing such as crushing, pulverization, drying, sieving, and classification may be performed. Processes to adjust particle size, such as sieving and classification, may be performed at any of the following stages: after the firing process, after the annealing process, or after the acid treatment.

[0049] [Wavelength converters, light-emitting components] The light-emitting member of this embodiment comprises a light-emitting element and a wavelength converter that converts light irradiated from the light-emitting element to emit light, wherein the wavelength converter has the above-mentioned β-type sialon phosphor particles.

[0050] An example of a method for manufacturing the wavelength conversion member of this embodiment includes a step of manufacturing the wavelength conversion member using β-type sialon phosphor particles obtained by a method for manufacturing β-type sialon phosphor particles.

[0051] The wavelength converter of this embodiment converts light irradiated from a light-emitting element to emit light, and has the above-mentioned β-type sialon phosphor particles. The wavelength converter may consist only of β-type sialon phosphor particles, or it may include a matrix in which β-type sialon phosphor particles are dispersed. Known materials can be used as the matrix, but examples include glass, resin, and inorganic materials.

[0052] The wavelength converter described above is not particularly limited in shape and may be configured in a plate shape, or it may be configured to seal a part of the light-emitting element or the entire light-emitting surface.

[0053] [Light-emitting device]

[0054] The light-emitting device according to this embodiment includes a light-emitting member that includes a light-emitting source (light-emitting element) and the wavelength converter described above. By combining a light source and a wavelength converter, it is possible to emit light with high emission intensity.

[0055] An example of a manufacturing method for the light-emitting device of this embodiment includes a step of mounting a wavelength conversion member obtained by a method for manufacturing a wavelength conversion member onto the light-emitting surface of a light-emitting light source.

[0056] An example of a light-emitting device is an LED package. The LED package may include a light-emitting source (LED chip), a substrate (lead frame) on which the light-emitting source is mounted, and a wavelength converter covering the light-emitting source. The LED chip may emit light with wavelengths ranging from near-ultraviolet to blue light, specifically 300 nm to 500 nm. The LED chip and the lead frame may be electrically connected by bonding wires. The wavelength converter may be covered with a cap made of synthetic resin.

[0057] The above wavelength converter may contain the above-mentioned β-type sialon phosphor particles, but may also contain other phosphors. Other phosphors may include, for example, α-type sialon phosphors, KSF phosphors, CASN phosphors, SCASN phosphors, and YAG phosphors. These phosphors may be used individually or in combination of two or more.

[0058] In the case of a light-emitting device using the above-mentioned β-type Sialon phosphor particles, by irradiating with near-ultraviolet light or visible light containing wavelengths between 300 nm and 500 nm as the excitation source, it exhibits green emission characteristics with a peak in wavelengths between 520 nm and 560 nm. Therefore, by combining a near-ultraviolet LED chip or a blue LED chip with β-type Sialon phosphor and one or more red, blue, yellow, or orange phosphors as the light-emitting source, white light can be produced.

[0059] For example, by combining a β-type sialon phosphor that exhibits green light with a KSF-based phosphor that exhibits red light, it can be suitably used in LEDs for backlights suitable for high color rendering TVs and the like.

[0060] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted. [Examples]

[0061] The present invention will be described in detail below with reference to examples, but the present invention is not limited in any way to the descriptions of these examples.

[0062] 1. Preparation of β-type Sialon phosphor particles <Comparative Example 1> (1) The following materials were weighed out to be 95.58% by mass of α-type silicon nitride (SN-E10 grade, oxygen content 1.0% by mass, manufactured by Ube Industries, Ltd.), 2.89% by mass of aluminum nitride (E grade, oxygen content 0.8% by mass, manufactured by Tokuyama Corporation), 0.93% by mass of aluminum oxide (TM-DAR grade, manufactured by Daimyo Chemical Co., Ltd.), and 0.60% by mass of europium oxide (RU grade, manufactured by Shin-Etsu Chemical Co., Ltd.). The resulting mixture was passed through a sieve with a mesh size of 250 μm to remove aggregates and obtain the raw material composition. Aggregates that did not pass through the sieve were crushed and the particle size was adjusted so that it could pass through the sieve.

[0063] (2) 200 g of the raw material composition prepared as described above was weighed into a cylindrical boron nitride container with a lid (manufactured by Denka Co., Ltd., a molded product mainly composed of boron nitride (product name: Denka Boron Nitride N-1), inner diameter: 10 cm, height: 10 cm). Then, this container was placed in an electric furnace equipped with a carbon heater and heated to 2000°C under a nitrogen gas atmosphere (pressure: 0.90 MPaG), and heated at a heating temperature of 2000°C for 10 hours (calcination process). After heating, the loosely aggregated mass of the sample in the container was taken into a mortar and crushed. After crushing, it was passed through a sieve with a mesh size of 250 μm to obtain a powdered first calcined body.

[0064] (3) Next, the first calcined body was filled into a cylindrical boron nitride container, and this container was placed in an electric furnace equipped with a carbon heater. Heating was started from a vacuum state, argon gas was introduced at 1000°C, and the temperature was raised to 1450°C under an argon gas atmosphere (pressure: 0.025 MPaG), and heating was carried out at a heating temperature of 1450°C for 5 hours (annealing process). After heating, the loosely aggregated mass of particles in the container was crushed in a mortar and pestle, and powder was obtained by passing it through a 250 μm sieve.

[0065] (4) Next, the powder obtained in (3) above was added to a solution of hydrofluoric acid (concentration: 50% by mass) and nitric acid (concentration: 70% by mass) diluted to a volume ratio of 2.5%. The solution was then acid-treated at 75°C for 30 minutes while stirring. After the acid treatment, stirring was stopped and the powder was allowed to settle, and the supernatant and the fine powder purified by the acid treatment were removed. Distilled water was then added and stirred again. The process of stopping stirring, allowing the powder to settle, and removing the supernatant and fine powder was repeated until the solution became neutral. The resulting precipitate was filtered, dried, and passed through a sieve with a mesh size of 250 μm to obtain the europium-activated β-type sialon phosphor particles of Comparative Example 1.

[0066] <Example 1> Example 1 prepared β - sialon phosphor particles under the same conditions as Comparative Example 1, except that the argon gas introduction temperature in (3) of Comparative Example 1 was changed from 1000 °C to 600 °C, and the acid concentration in (4) was changed from 2.5% to 25% by volume.

[0067] <Example 2> Example 2 was prepared under the same conditions as Example 1, except that the mixing ratio of raw materials in Example 1 was changed to 93.29% by mass of α - silicon nitride powder, 2.82% by mass of aluminum nitride powder, 0.91% by mass of aluminum oxide powder, 0.98% by mass of europium oxide powder, and 2.00% by mass of β - sialon phosphor particles as a nucleating agent.

[0068] <Example 3> Example 3 was prepared under the same conditions as Example 1, except that the argon gas introduction temperature in Example 1 was changed from 600 °C to 800 °C.

[0069] 2. Evaluation For the β - sialon phosphor particles of each example and each comparative example, the following characteristics and evaluation items were evaluated.

[0070] <SEM Observation> The surface of the β - sialon phosphor particles was observed with a scanning electron microscope (SEM) at a magnification of 50000 times under the following conditions, and the presence or absence of "a high - density stripe region where the stripe density of the stripe pattern is 15 stripes / μm or more in a 2.5 - μm square", "a linear region where the stripe density of the stripe pattern is 15 stripes / μm or more and the stripe pattern is composed of linear stripes with a length of
μm or more", "a curved region where the stripe density of the stripe pattern is 15 stripes / μm or more in a 2.5 - μm square and the stripe pattern is composed of curved stripes", "a medium - density stripe region where the stripe density of the stripe pattern is 5 stripes / μm or more and less than 15 stripes / μm in a 2.5 - μm square", and "a smooth region of 2.5 - μm square or more" was evaluated. What was observed was marked as "〇" and what was not observed was marked as "×" and shown in Table 1. (Conditions) As a pretreatment, the sample was fixed with carbon paste and observed using a Hitachi High-Tech SU8000 field emission scanning electron microscope at an acceleration voltage of 1kV and an observation magnification of 50,000x.

[0071] Figure 2 shows a scanning electron microscope (SEM) image of the β-type sialon phosphor particles of Example 1, Figure 3 shows a scanning electron microscope (SEM) image of the β-type sialon phosphor particles of Example 2, Figure 4 shows a scanning electron microscope (SEM) image of the β-type sialon phosphor particles of Example 3, and Figure 5 shows a scanning electron microscope (SEM) image of the β-type sialon phosphor particles of Comparative Example 1.

[0072] <50% cumulative diameter (D50)> The particle size distribution of each phosphor powder was measured in accordance with the method for measuring particle size distribution by laser diffraction and scattering described in JIS R 1629:1997 "Method for measuring particle size distribution of fine ceramic raw materials by laser diffraction and scattering". Specifically, first, 0.03 g of the phosphor powder to be measured was added to 100 mL of deionized water containing 0.05 mass% sodium hexametaphosphate, and the sample was dispersed for 3 minutes using an ultrasonic homogenizer (manufactured by Nippon Seiki Seisakusho Co., Ltd., product name "Ultrasonic Homogenizer US-150E", Amplitude: 100%, oscillation frequency: 19.5 KHz, tip size: φ20, amplitude: 32 ± 2 μm) to prepare the measurement sample. After that, the particle size distribution was measured using a particle size distribution analyzer (manufactured by Microtrac-Bell Co., Ltd., product name "Microtrac MT3300EX II"). From the obtained particle size distribution, the particle size D50 corresponding to 50% of the cumulative fraction based on volume was determined. The results are shown in Table 1.

[0073] <Luminous properties> [Manufacturing of light-emitting elements] The β-type sialon phosphor particles of the examples and comparative examples were added together with KSF phosphor (KR-2K01, emission peak wavelength of 631 nm when excited with 455 nm wavelength light, manufactured by Denka Co., Ltd.) to a curable silicone resin (KER-6150, manufactured by Shin-Etsu Chemical Co., Ltd.). After degassing and kneading, the mixture was potted into a surface-mount type package to which a blue light-emitting semiconductor element with a peak wavelength of 450 nm was bonded, and then the package was heat-cured to produce a white LED. The addition ratio of KSF phosphor to β-type sialon phosphor particles was adjusted so that the chromaticity coordinates (x, y) of the white LED were (0.28, 0.27) when power was applied and light was emitted. [Luminance: Relative total luminous flux] Ten white LEDs containing β-type Sialon phosphor particles from the examples and comparative examples were selected, particularly those with a chromaticity x within the range of 0.275 to 0.284 and a chromaticity y within the range of 0.265 to 0.274. Each white LED was energized to emit light, and the total luminous flux was determined using a total luminous flux measuring device combining a spectrophotometer (MCPD-9800, manufactured by Otsuka Electronics Co., Ltd.) with a 300 mm diameter integrating hemisphere (manufactured by Otsuka Electronics Co., Ltd.). The average value of these measurements was taken as the representative value of the total luminous flux. Table 1 shows the relative values ​​of the total luminous flux (%), with the total luminous flux of Comparative Example 1 set to 100%. A larger relative luminous flux indicates higher brightness as a light-emitting element.

[0074] [Table 1] [Explanation of Symbols]

[0075] A High-density striped region B Medium-density fringed region C curve area D Linear region E smooth region 10 β-type Sialon phosphor particles

Claims

1. β-type Sialon phosphor particles having a particle size (D50) of 50% of the cumulative volume frequency of the particle size distribution measured by wet laser diffraction particle size distribution method, where the particle size is between 5 and 150 μm. Beta-type sialon phosphor particles that satisfy the following condition i. (Condition i) When the surface of the β-type Sialon phosphor particles is observed at a magnification of 50,000x using a scanning electron microscope (SEM), a striped pattern can be confirmed.

2. The β-type sialon phosphor particles according to claim 1, In condition i, the striped pattern is a β-type sialon phosphor particle having a high-density striped region where the stripe density of the striped pattern is 15 stripes / μm or more in a 2.5 μm square area.

3. β-type sialon phosphor particles according to claim 1 or 2, In condition i, the striped pattern is a β-type sialon phosphor particle having a stripe density of 15 stripes / μm or more, and the striped pattern has a linear region composed of linear stripes with a length of 1 μm or more.

4. β-type sialon phosphor particles according to claim 1 or 2, In condition i, the striped pattern is a β-type sialon phosphor particle having a stripe density of 15 stripes / μm or more in a 2.5 μm square area, and the striped pattern has a curved region composed of curved stripes.

5. β-type sialon phosphor particles according to claim 1 or 2, In condition i, the striped pattern is a β-type sialon phosphor particle having a medium-density striped region where the stripe density of the striped pattern in a 2.5 μm square area is 5 stripes / μm or more and less than 15 stripes / μm.

6. β-type sialon phosphor particles according to claim 1 or 2, Furthermore, β-type sialon phosphor particles that satisfy condition ii. (Condition ii) When the surface of the β-type Sialon phosphor particle is observed with a scanning electron microscope (SEM) at a magnification of 50,000x, no smooth area of ​​2.5 μm square or larger is observed.

7. A β-type sialon phosphor powder comprising β-type sialon phosphor particles according to claim 1 or 2.

8. A light-emitting device including a light-emitting light source and a wavelength conversion member, The wavelength conversion member includes phosphor powder, The phosphor powder is a light-emitting device comprising the β-type sialon phosphor powder described in claim 7.

9. A light-emitting device according to claim 8, The light-emitting device includes an LED chip that generates light with a wavelength of 300 nm to 500 nm.

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