β-sialon phosphor, light-emitting member, and light-emitting device

Abstract

The β-SiAlON phosphor of the present invention contains europium in solid solution and is configured such that, when the absorbance of the spectrum is converted into a KM value by a Kulbeka-Munk function in the spectrum of the β-SiAlON phosphor determined by FT-IR and the KM value at a wave number of 3050 cm-1 is taken as E, the KM value at a wave number of 3330 cm-1 is taken as F, and the KM value at a wave number of 3500 cm-1 is taken as G, E, F, and G satisfy 1.8<F / E and 1.8>G / E.

Description

β-type sialon phosphor, light-emitting member, and light-emitting device

[0001] The present invention relates to a β-sialon phosphor, a light-emitting member, and a light-emitting device.

[0002] Various developments have been made in the field of β-sialon phosphors. Patent Document 1, for example, describes a known technique of this type. Patent Document 1, paragraph 0009, example 6, and other sections describe a method for producing a β-sialon phosphor, which comprises: heat-treating a composition containing silicon nitride containing aluminum, oxygen atoms, and europium; mixing the resulting mixture with a sodium hydroxide aqueous solution; subjecting the resulting mixture to a first thermal base treatment at 70°C for 3 hours in the atmosphere; and then subjecting the resulting mixture to a second thermal base treatment at 200°C for 2 hours in a nitrogen atmosphere. Furthermore, paragraph 0051 of Patent Document 1 describes a first temperature, which is the heating temperature for the first thermal base treatment, as being 50°C or higher and 150°C or lower.

[0003] JP 2017-110206 A

[0004] However, as a result of investigations by the present inventors, it was found that there is room for improvement in the reliability of the LED brightness when the LED is energized (continuously lit) in a high-temperature, high-humidity environment in the β-sialon phosphor obtained by the manufacturing method described in Patent Document 1.

[0005] As a result of further investigation, the present inventors have concluded that the abundance ratio of Si-OH groups among functional groups present on the surface of a β-sialon phosphor can be stably evaluated by utilizing an index using a KM value obtained by converting absorbance in an FT-IR spectrum using a Kubelka-Munk function, and have found that the index can be one having at least one of the following (P1) and (P2), or one having at least one of the following (Q1) to (Q6): (P1) E, F, G satisfy 1.8<F / E and 1.8>G / E. (P2) E, F, H satisfy 1.8<F / E and 2.0>H / E. (Q1) A, B satisfy 0.31>B / A. (Q2) A, C satisfy 0.44>C / A. (Q3) A, D satisfy 0.21>D / A. (Q4) L, A, C satisfy 1.4<A / L and 0.81>C / L. (Q5) L, A, M satisfy 1.4<A / L and 0.67>M / L. (Q6) L, A, E, F satisfy 0.94>((A / L) / (F / E)). However, in the spectrum of the β-sialon phosphor obtained by FT-IR before exposure for 1000 hours in an environment of a temperature of 85°C and a humidity of 85%, the absorbance of the spectrum was converted into a KM value by the Kubelka-Munk function, and the absorbance was measured at a wave number of 3050 cm －１ The KM value is E, and the wave number is 3330 cm －１ The KM value is F, and the wave number is 3500 cm －１ The KM value is G, and the wave number is 3530 cm －１ The KM value of the β-sialon phosphor is defined as H. In the spectrum of the β-sialon phosphor obtained by FT-IR after exposure for 1000 hours in an environment of a temperature of 85°C and a humidity of 85%, the absorbance of the spectrum is converted into a KM value by the Kubelka-Munk function, and the KM value at a wave number of 3330 cm is defined as H. －１ The KM value is A and the wave number is 3550 cm －１ The KM value is B, and the wave number is 3500 cm －１ The KM value is C and the wave number is 3600 cm －１ The KM value is D, and the wave number is 3050 cm －１ The KM value is L, and the wave number is 3530 cm －１The KM value of the above is defined as M. As a result of further intensive studies, the inventors have found that by appropriately controlling the numerical range of each index, it is possible to improve the reliability of LED luminance in an LED current-carrying (continuous lighting) test of a β-sialon phosphor under a high-temperature and high-humidity environment, and have thus completed the present invention.

[0006] According to one aspect of the present invention, there are provided the following β-sialon phosphor, light-emitting member, and light-emitting device: 1. A β-sialon phosphor in which europium is dissolved as a solid solution, wherein the absorbance of the spectrum of the β-sialon phosphor obtained by FT-IR is converted into a KM value using the Kubelka-Munk function, and the absorbance at a wave number of 3050 cm is －１ The KM value is E, and the wave number is 3330 cm －１ The KM value is F, and the wave number is 3500 cm －１ The KM value is G, and the wave number is 3530 cm －１ 1. A β-sialon phosphor having at least one of the following conditions (P1) and (P2), where H is the KM value of the above formula (P1) and (P2): (P1) E, F, and G satisfy 1.8<F / E and 1.8>G / E, and (P2) E, F, and H satisfy 1.8<F / E and 2.0>H / E. 2. A β-sialon phosphor having europium as a solid solution, wherein the spectrum of the β-sialon phosphor obtained by FT-IR after exposure for 1000 hours in an environment at a temperature of 85°C and a humidity of 85% is converted from the absorbance of the spectrum to a KM value using the Kubelka-Munk function, and the absorbance at a wavenumber of 3330 cm is found to be 1.8<F / E and 1.8>G / E. －１ The KM value is A and the wave number is 3550 cm －１ The KM value is B, and the wave number is 3500 cm －１ The KM value is C and the wave number is 3600 cm －１ The KM value is D, and the wave number is 3050 cm －１ The KM value is L, and the wave number is 3530 cm －１ The KM value of the above is defined as M, and in the spectrum of the β-sialon phosphor obtained by FT-IR before exposure for 1000 hours in an environment of a temperature of 85°C and a humidity of 85%, the absorbance of the spectrum is converted into a KM value by the Kubelka-Munk function, and the KM value at a wavenumber of 3050 cm is －１ The KM value is E, and the wave number is 3330 cm －１β-sialon phosphor having at least one of the following (Q1) to (Q6), where F is the KM value of the above formula (1), (Q1) A and B satisfy 0.31 > B / A (Q2) A and C satisfy 0.44 > C / A (Q3) A and D satisfy 0.21 > D / A (Q4) L, A and C satisfy 1.4 < A / L and 0.81 > C / L (Q5) L, A and M satisfy 1.4 < A / L and 0.67 > M / L (Q6) L, A, E and F satisfy 0.94 > ((A / L) / (F / E)) 3. The β-sialon phosphor according to 1. or 2., wherein the amount of fluorine in the surface composition of the β-sialon phosphor is less than 0.4 atom %. 4. The β-sialon phosphor according to any one of 1. to 3., wherein the amount of boron in the surface composition of the β-sialon phosphor is less than 0.5 atom %. 5. A light emitting member comprising: a light emitting element; and a wavelength converter that converts light irradiated from the light emitting element and emits light, wherein the wavelength converter has the β-sialon phosphor according to any one of 1. to 4.. 6. A light emitting device comprising the light emitting member according to 5.

[0007] According to the present invention, there are provided a β-sialon phosphor that exhibits excellent reliability in LED luminance when the LED is energized (continuously lit) in a high-temperature, high-humidity environment, and a light-emitting member and a light-emitting device that use the same.

[0008] FT-IR spectrum of the β-sialon phosphor at a wave number of 3050 cm before exposure to a temperature of 85°C and a humidity of 85% for 1000 hours. －１ The FT-IR spectrum of the β-sialon phosphor before exposure to a temperature of 85°C and a humidity of 85% for 1000 hours is shown at a wave number of 3050 cm. －１ The FT-IR spectrum of the β-sialon phosphor before exposure to a temperature of 85°C and a humidity of 85% for 1000 hours is shown at a wave number of 3050 cm. －１The FT-IR spectrum of the β-sialon phosphor before exposure to a temperature of 85°C and a humidity of 85% for 1000 hours is shown at a wave number of 3330 cm. －１ The FT-IR spectrum of the β-sialon phosphor before exposure to a temperature of 85°C and a humidity of 85% for 1000 hours is shown at a wave number of 3330 cm. －１ The FT-IR spectrum of the β-sialon phosphor before exposure to a temperature of 85°C and a humidity of 85% for 1000 hours is shown at a wave number of 3330 cm. －１ FT-IR spectrum of β-sialon phosphor before exposure to a temperature of 85°C and a humidity of 85% for 1000 hours. FT-IR spectrum of β-sialon phosphor before exposure to a temperature of 85°C and a humidity of 85% for 1000 hours. FT-IR spectrum of β-sialon phosphor before exposure to a temperature of 85°C and a humidity of 85% for 1000 hours. FT-IR spectrum of β-sialon phosphor after exposure to a temperature of 85°C and a humidity of 85% for 1000 hours at a wavenumber of 3050 cm －１ The FT-IR spectrum of the β-sialon phosphor after exposure to a temperature of 85°C and a humidity of 85% for 1000 hours is shown at a wave number of 3050 cm. －１ The FT-IR spectrum of the β-sialon phosphor after exposure to a temperature of 85°C and a humidity of 85% for 1000 hours is shown at a wave number of 3050 cm. －１ The FT-IR spectrum of the β-sialon phosphor after exposure to a temperature of 85°C and a humidity of 85% for 1000 hours is shown at a wave number of 3330 cm. －１ The FT-IR spectrum of the β-sialon phosphor after exposure to a temperature of 85°C and a humidity of 85% for 1000 hours is shown at a wave number of 3330 cm. －１ The FT-IR spectrum of the β-sialon phosphor after exposure to a temperature of 85°C and a humidity of 85% for 1000 hours is shown at a wave number of 3330 cm. －１8 shows the spectrum normalized by the KM value of 85°C. 8 shows the FT-IR spectrum of a β-sialon phosphor after 1000 hours of exposure at a temperature of 85°C and humidity of 85%. 8 shows the FT-IR spectrum of a β-sialon phosphor after 1000 hours of exposure at a temperature of 85°C and humidity of 85%. 8 shows the FT-IR spectrum of a β-sialon phosphor after 1000 hours of exposure at a temperature of 85°C and humidity of 85%.

[0009] An outline of the β-sialon phosphor of this embodiment will be described.

[0010] (Embodiment P) A β-sialon phosphor according to a first example of this embodiment P is a β-sialon phosphor in which europium is solid-dissolved. In the spectrum of this β-sialon phosphor obtained by FT-IR, the absorbance of the spectrum is converted into a KM value by the Kubelka-Munk function, and the absorbance at a wave number of 3050 cm is －１ The KM value is E, and the wave number is 3330 cm －１ The KM value is F, and the wave number is 3500 cm －１ When the KM value of the above is G, E, F, and G are configured to satisfy 1.8<F / E and 1.8>G / E.

[0011] The β-sialon phosphor of the second example of this embodiment P is a β-sialon phosphor in which europium is solid-solved, and in the spectrum of the β-sialon phosphor obtained by FT-IR, the absorbance of the spectrum is converted into a KM value by the Kubelka-Munk function, and the absorbance at a wave number of 3050 cm －１ The KM value is E, and the wave number is 3330 cm －１ The KM value is F, and the wave number is 3530 cm －１ When the KM value of the above is H, E, F, and H are configured to satisfy 1.8<F / E and 2.0>H / E.

[0012] According to the findings of the present inventors, it has been found that the stable state of the surface of a β-sialon phosphor when an LED is energized (continuously lit) in a high-temperature and high-humidity environment can be evaluated based on the infrared absorption spectrum of the β-sialon phosphor determined by FT-IR. Specifically, in the infrared absorption spectrum, －１ is the NH group, 3500 cm －１is the Si-OH group, 3530 cm －１ represents the Si-OH group. －１ The KM value (F) is relatively large and 3500 cm －１ and / or a relatively small KM value (G) of 3330 cm －１ The KM value (F) is relatively large and 3530 cm －１ A relatively small KM value (H) indicates a small proportion of Si—OH groups among the functional groups present on the surface of the β-sialon phosphor. While the detailed mechanism is unclear, it is believed that even if the phosphor is exposed to moisture during the manufacturing process of a light-emitting device including a β-sialon phosphor or during use of the light-emitting device, if the proportion of Si—OH groups present on the surface of the β-sialon phosphor is small, fluctuations in the surface state are suppressed, thereby suppressing fluctuations in the light-emitting characteristics of LEDs derived from the β-sialon phosphor, thereby improving the reliability of the light-emitting device. Furthermore, a large number of Si—OH groups increases the amount of adsorbed water due to hydrogen bonding. During LED power-on (lighting) reliability tests in a high-temperature, high-humidity environment, the adsorbed water is desorbed or vaporized by heat emitted from the LED, or the OH of the Si—OH group is desorbed or vaporized as water due to heat, forming gaps at the interface between the phosphor and the resin sealing it. This makes it easier for light to be reflected and scattered, making it difficult for the excitation light that excites the phosphor to be absorbed by the phosphor, resulting in reduced LED brightness. Furthermore, because phosphors are often placed near LED chips, there is concern that the aforementioned adsorbed water, desorbed water derived from Si-OH groups, and evaporated water may accelerate deterioration of the LED chip itself. When the proportion of Si-OH groups is small, fluctuations in the light-emitting characteristics of LEDs derived from β-sialon phosphors can be suppressed.

[0013] In addition, in this embodiment P, the FT-IR spectrum of the β-sialon phosphor is the FT-IR spectrum after KM transformation using the Kubelka-Munk function, and for each wave number value, the 3050 cm －１By normalizing the ratios by F / E and G / E as the first indexes and F / E and H / E as the second indexes, it is possible to reproducibly evaluate the stable state of the surface of a β-sialon phosphor when an LED is energized (continuously lit) in a high-temperature, high-humidity environment.

[0014] The lower limit of F / E is greater than 1.8, preferably 1.9 or greater, and more preferably 2.1 or greater. This improves the reliability of LED brightness when the LED is energized (continuously lit) in a high-temperature, high-humidity environment. The upper limit of F / E is not particularly limited, but may be 6.0 or less, or 4.0 or less.

[0015] In the first example of the β-sialon phosphor, the upper limit of G / E is less than 1.8, preferably less than 1.4, and more preferably 1.1 or less. This improves the reliability of LED brightness when the LED is energized (continuously lit) in a high-temperature, high-humidity environment. The lower limit of G / E is not particularly limited, but may be 0.05 or more, or 0.1 or more.

[0016] In the β-sialon phosphor of the second example, the upper limit of H / E is less than 1.8, preferably less than 1.19, and more preferably 1.16 or less. This improves the reliability of LED brightness when the LED is energized (continuously lit) in a high-temperature, high-humidity environment. The lower limit of H / E is not particularly limited, but may be 0.05 or more, or 0.1 or more.

[0017] In this embodiment P, it is possible to control the above F / E, G / E, and H / E by appropriately selecting, for example, the type and amount of each component contained in the β-sialon phosphor, the preparation method of the β-sialon phosphor, etc. Among these, examples of factors for setting the above F / E, G / E, and H / E within the desired numerical range include subjecting the β-sialon phosphor to an alkali treatment, particularly subjecting the surface of the β-sialon phosphor to an alkali treatment in which the phosphor is heated in a state where water is substantially absent, and appropriately performing a water washing treatment or a decantation treatment.

[0018] (Embodiment Q) The β-sialon phosphor of this embodiment Q is a β-sialon phosphor in which europium is dissolved. The β-sialon phosphor is exposed for 1000 hours in an environment of 85°C temperature and 85% humidity, and an infrared absorption spectrum is obtained by FT-IR. The absorbance of the infrared absorption spectrum is converted into a KM value using the Kubelka-Munk function, and the absorbance at a wavenumber of 3330 cm is －１ The KM value is A and the wave number is 3500 cm －１ The KM value is C and the wave number is 3550 cm －１ The KM value is B, and the wave number is 3600 cm －１ The KM value is D, and the wave number is 3050 cm －１ The KM value is L, and the wave number is 3530 cm －１ The KM value of the sample is defined as M. The infrared absorption spectrum is determined by FT-IR using the sample before it is exposed to an environment of 85°C temperature and 85% humidity for 1000 hours. The absorbance of the infrared absorption spectrum is converted into a KM value using the Kubelka-Munk function, and the KM value is calculated as M. －１ The KM value is F, and the wave number is 3050 cm －１ The KM value of the above is defined as E. The β-sialon phosphor of this embodiment Q has a KM value at a normalized predetermined wavenumber, which is determined from the FT-IR spectrum after such KM conversion, that satisfies at least one of the conditions (Q1) to (Q6) described below. The sample exposed for 1000 hours in an environment of a temperature of 85°C and a humidity of 85% was then held for 1 hour in an environment of a temperature of 15°C to 30°C and a humidity of 45 to 85% after exposure, and then stored in a polyethylene bottle (hard bottle). When various measurements, analyses, and evaluations were performed, the sample was removed from the polyethylene bottle and measured, analyzed, and evaluated.

[0019] (Q1) A β-sialon phosphor is configured so that A and B satisfy 0.31 > B / A. (Q2) A β-sialon phosphor is configured so that A and C satisfy 0.44 > C / A. (Q3) A β-sialon phosphor is configured so that A and D satisfy 0.21 > D / A. (Q4) A β-sialon phosphor is configured so that L, A, and C satisfy 1.4 < A / L and 0.81 > C / L. (Q5) A β-sialon phosphor is configured so that L, A, and M satisfy 1.4 < A / L and 0.67 > M / L. (Q6) A β-sialon phosphor is configured so that L, A, F, and E satisfy 0.94 > ((A / L) / (F / E)).

[0020] According to the findings of the present inventors, it has been found that the stable state of the surface of a β-sialon phosphor when an LED is energized (continuously lit) in a high-temperature and high-humidity environment can be evaluated based on the infrared absorption spectrum of the β-sialon phosphor determined by FT-IR. Specifically, in the infrared absorption spectrum, －１ is the Si-OH group, 3550 cm －１ is the Si-OH group, 3600 cm －１ represents the Si-OH group. Therefore, the wave number is 3550 cm －１ KM value (B), wave number 3500 cm －１ KM value (C), and wave number 3600 cm －１ The fact that at least one of the indexes in the group consisting of the KM value (D) of 3330 cm or more is small means that the proportion of Si—OH groups in the functional groups present on the surface of the β-sialon phosphor is small. －１ is the NH group, 3500 cm －１ is the Si-OH group, 3530 cm －１ represents the Si-OH group. Therefore, the wave number is 3330 cm －１ The KM value (A) is relatively large and the wave number is 3500 cm －１ The KM value (C) is relatively small, and / or the wave number is 3330 cm －１ The KM value (A) is relatively large and the wave number is 3530 cm －１A relatively small KM value (M) indicates a small proportion of Si—OH groups among the functional groups present on the surface of the β-sialon phosphor. While the detailed mechanism is unclear, it is believed that even if the phosphor is exposed to moisture during the manufacturing process of a light-emitting device including a β-sialon phosphor or during use of the light-emitting device, if the proportion of Si—OH groups present on the surface of the β-sialon phosphor is small, fluctuations in the surface state are suppressed, thereby suppressing fluctuations in the light-emitting characteristics of LEDs derived from the β-sialon phosphor, thereby improving the reliability of the light-emitting device. Furthermore, a large number of Si—OH groups increases the amount of adsorbed water due to hydrogen bonding. During LED power-on (lighting) reliability tests in a high-temperature, high-humidity environment, the adsorbed water is desorbed or vaporized by heat emitted from the LED, or the OH of the Si—OH group is desorbed or vaporized as water due to heat, forming gaps at the interface between the phosphor and the resin sealing it. This makes it easier for light to be reflected and scattered, making it difficult for the excitation light that excites the phosphor to be absorbed by the phosphor, resulting in reduced LED brightness. Furthermore, since phosphors are often placed near LED chips, there is concern that the above-mentioned adsorbed water, desorption from Si-OH groups, and vaporized water may accelerate the deterioration of the LED chip itself. When the proportion of Si-OH groups is small, fluctuations in the light-emitting characteristics of LEDs derived from β-sialon phosphors can be suppressed. In addition, the luminescence intensity of LEDs after exposure at a temperature of 85°C and humidity of 85% was 3050 cm after 1000 hours compared to before exposure. －１ The wave number 3330 cm represents the NH group normalized by the value －１ The decrease in the KM value suggests that there were many NH groups and few Si-OH groups on the surface before exposure.

[0021] In addition, in this embodiment Q, the FT-IR spectrum of the β-sialon phosphor after exposure to a temperature of 85°C and a humidity of 85% for 1000 hours is the FT-IR spectrum after KM transformation using the Kubelka-Munk function. －１ The use of B / A, C / A, or D / A as an index normalized by the KM value (A) of the 3050 cm wavenumber, which represents the valley portion where there are few absorbing components, is also important. －１A / L and C / L, and / or A / L and M / L are used as indexes normalized from the value (L) of －１ By using ((A / L) / (F / E)) as an index normalized by the value (E) of A / L, it is possible to reproducibly evaluate the stable state of the surface of a β-sialon phosphor when an LED is energized (continuously lit) in a high-temperature, high-humidity environment.

[0022] In the first example of the β-sialon phosphor, the upper limit of B / A is less than 0.31, preferably 0.29 or less, and more preferably 0.27 or less. This can improve the reliability of LED brightness when the LED is energized (continuously lit) in a high-temperature, high-humidity environment. The lower limit of B / A is not particularly limited, but may be 0.05 or more, or 0.10 or more.

[0023] In the second example of the β-sialon phosphor, the upper limit of C / A is less than 0.44, preferably less than 0.40, and more preferably 0.37 or less. This improves the reliability of the LED brightness when the LED is energized (continuously lit) in a high-temperature, high-humidity environment. The lower limit of C / A is not particularly limited, but may be 0.05 or more, or 0.10 or more.

[0024] In the third example of the β-sialon phosphor, the upper limit of D / A is less than 0.21, preferably 0.20 or less, and more preferably 0.19 or less. This improves the reliability of the LED brightness when the LED is energized (continuously lit) in a high-temperature, high-humidity environment. The lower limit of D / A is not particularly limited, but may be 0.01 or more, or 0.05 or more.

[0025] In the β-sialon phosphor of the fourth or fifth example, the lower limit of A / L is more than 1.4, preferably 1.45 or more, and more preferably 1.50 or more. This can improve the reliability of LED brightness when the LED is energized (continuously lit) in a high-temperature, high-humidity environment. The upper limit of A / L is not particularly limited, but may be 4.0 or less, or 3.0 or less.

[0026] In the fourth example of the β-sialon phosphor, the upper limit of C / L is less than 0.81, preferably 0.79 or less, and more preferably 0.76 or less. This improves the reliability of the LED brightness when the LED is energized (continuously lit) in a high-temperature, high-humidity environment. The lower limit of C / L is not particularly limited, but may be 0.05 or more, or 0.10 or more.

[0027] In the fifth example of the β-sialon phosphor, the upper limit of M / L is less than 0.67, preferably 0.64 or less, and more preferably 0.61 or less. This ensures reliable LED brightness when the LED is energized (continuously lit) in a high-temperature, high-humidity environment. The lower limit of M / L is not particularly limited, but may be 0.01 or more, or 0.05 or more.

[0028] In the sixth example of the β-sialon phosphor, the upper limit of ((A / L) / (F / E)) is less than 0.94, preferably 0.91 or less, and more preferably 0.89 or less. This ensures reliable LED brightness when the LED is energized (continuously lit) in a high-temperature, high-humidity environment. The lower limit of M / L is not particularly limited, but may be 0.01 or more, or 0.05 or more.

[0029] In this embodiment Q, it is possible to control the above B / A, C / A, D / A, A / L, C / L, M / L, and ((A / L) / (F / E)) by appropriately selecting, for example, the type and amount of each component contained in the β-sialon phosphor, the preparation method of the β-sialon phosphor, etc. Among these, for example, elements for setting the above B / A, C / A, D / A, A / L, C / L, M / L, and ((A / L) / (F / E)) within the desired numerical range include subjecting the β-sialon phosphor to an alkali treatment, particularly subjecting the surface of the β-sialon phosphor to an alkali treatment in which the phosphor is heated in a state where water is substantially absent, and appropriately performing a water washing treatment or a decantation treatment.

[0030] The β-sialon phosphor of this embodiment will be described in detail below.

[0031] The β-sialon phosphor of this embodiment is extremely useful as a phosphor for light sources such as light-emitting diodes (hereinafter referred to as LEDs).

[0032] The β-sialon phosphor can absorb blue light with a wavelength in the range of 420 nm to 480 nm, for example, and emit light having a peak wavelength in the range of more than 480 nm and not more than 800 nm.

[0033] The β-sialon phosphor is not particularly limited as long as it can be used as a phosphor, but is preferably made of europium-activated β-sialon in which europium is solid-dissolved.

[0034] The europium-activated β-sialon phosphor has the general formula Si ６－ｚ Al ｚ O ｚ N ８－ｚ :Eu ２＋ (0<z≦4.2) The general formula is Si ６－ｚ Al ｚ O ｚ N ８－ｚ :Eu ２＋ In the above, the z value and the europium content are not particularly limited, but the z value is, for example, more than 0 and not more than 4.2, and from the viewpoint of further improving the emission intensity of the europium-activated β-sialon phosphor, is preferably 0.002 or more and 1.0 or less. Furthermore, the europium content in the europium-activated β-sialon phosphor is preferably, for example, 0.1 mass % or more and 2.0 mass % or less.

[0035] The upper limit of (D90-D10) / D50 of the β-sialon phosphor powder may be, for example, 2.00 or less, 1.50 or less, 1.00 or less, 0.90 or less, or 0.80 or less, while the lower limit of (D90-D10) / D50 of the β-sialon phosphor powder may be, for example, 0.50 or more, 0.60 or more, or 0.70 or more.

[0036] The upper limit of D10 of the β-sialon phosphor powder may be, for example, 16 μm or less, 14 μm or less, 12 μm or less, 10 μm or less, or 8 μm or less, while the lower limit of D10 of the β-sialon phosphor powder may be, for example, 1 μm or more, 5 μm or more, or 7 μm or more.

[0037] The upper limit of D50 of the β-sialon phosphor powder may be, for example, 40 μm or less, 30 μm or less, 20 μm or less, or 12 μm or less, while the lower limit of D50 of the β-sialon phosphor powder may be, for example, 5 μm or more, 8 μm or more, or 10 μm or more.

[0038] The upper limit of D90 of the β-sialon phosphor powder may be, for example, 60 μm or less, 40 μm or less, 30 μm or less, or 25 μm or less, while the lower limit of D90 of the β-sialon phosphor powder may be, for example, 15 μm or more, 18 μm or more, or 21 μm or more.

[0039] In this specification, D10, D50, and D90 refer to the particle sizes at which the cumulative values ​​from the smallest particle size reach 10%, 50%, and 90%, respectively, in the volume-based particle size distribution curve measured by laser diffraction / scattering. The particle sizes were measured in accordance with the particle size distribution measurement method by laser diffraction / scattering described in JIS R 1629:1997, "Method for measuring particle size distribution of fine ceramic raw materials by laser diffraction / scattering." A particle size distribution measurement device (manufactured by Microtrac-Bell Corporation, product name: "Microtrac MT3300EX II") was used for the measurement. Specifically, 0.1 g of the phosphor to be measured was first added to 100 mL of ion-exchanged water, and the mixture was dispersed for 3 minutes using an ultrasonic homogenizer (manufactured by Nippon Seiki Seisakusho Co., Ltd., product name: "Ultrasonic Homogenizer US-150E", tip size: φ20, amplitude: 100%, oscillation frequency: 19.5 kHz, amplitude: approximately 31 μm) to prepare a measurement sample. Thereafter, the particle size was measured using a particle size distribution measuring device.

[0040] The surface composition of a β-sialon phosphor can be obtained by X-ray photoelectron spectroscopy (XPS). The measurement conditions are as follows: Measurement equipment: X-ray photoelectron spectroscopy (ULVAC-PHI, Inc., PHI5000 VersaProbe II) Excitation source: Al-X-ray source (Al K Alpha) Output: 15 kV-50 W Measurement area: φ200 μm Pass energy: 46.95 eV Energy step size: 0.05 eV Time per step: 50 ms Number of scans: 10 Time: 13 min / point Note: Narrow scan, average of three measurements. The surface composition was analyzed so that the total of B, N, O, F, Na, Al, Si, and Eu was 100 atom % (carbon was excluded).

[0041] In the surface composition of the β-sialon phosphor, the amount of fluorine is, for example, less than 0.4 atom%, preferably 0.3 atom% or less, and more preferably 0.2 atom% or less. The amount of fluorine in the surface composition may be below the detection limit. In addition, in the surface composition of the β-sialon phosphor, the amount of boron is, for example, less than 0.5 atom%, preferably 0.4 atom% or less, and more preferably 0.3 atom% or less. The amount of boron in the surface composition may be below the detection limit. In the surface composition of the β-sialon phosphor, the amount of sodium is, for example, less than 0.3 atom%, preferably 0.2 atom% or less, and more preferably 0.1 atom% or less. The amount of sodium in the surface composition may be below the detection limit.

[0042] The 800 nm diffuse reflectance of the β-sialon phosphor is, for example, 90% or more, preferably 92% or more, and more preferably 94% or more. This allows for the realization of a β-sialon phosphor with excellent optical properties. The 500 nm diffuse reflectance is, for example, 75% or more, preferably 80% or more, and more preferably 84% or more. This allows for the realization of a β-sialon phosphor with excellent optical properties.

[0043] Next, a method for producing the β-sialon phosphor of this embodiment will be described.

[0044] An example of a method for producing a β-sialon phosphor of this embodiment includes a preparation step of preparing a β-sialon phosphor, and an alkali treatment step of subjecting the surface of the β-sialon phosphor to alkali treatment.

[0045] The preparation step for preparing the β-sialon phosphor may be performed by a known method, but may also include, for example, a firing step in which raw material powders containing silicon, aluminum, and an activator element are mixed and the mixture is fired to obtain a fired product, and at least one or more post-treatment steps of crushing, sieving, annealing, acid treatment, etc., of the fired product after the firing step. The post-treatment steps can be performed in any order. The alkali treatment step may be performed after the classification step, or may be performed after the acid treatment.

[0046] The firing temperature in the firing step is, for example, 1800°C or higher and 2100°C or lower, preferably 1850°C or higher and 2050°C or lower. By setting the firing temperature to the above lower limit or higher, the luminescence intensity can be improved. The firing step may be performed multiple times. In addition, when firing is performed for the second or subsequent times, part of the raw materials may be added.

[0047] The ambient temperature during the annealing step is, for example, 1100° C. or higher and 1800° C. or lower, preferably 1300° C. or higher and 1750° C. or lower. By setting the annealing temperature to the above-mentioned lower limit or higher, the emission intensity can be improved. By setting the annealing temperature to the above-mentioned upper limit or lower, the crystallinity can be improved and a decrease in the emission peak intensity can be suppressed.

[0048] The atmospheric gas used in the annealing step is selected from the group consisting of a rare gas of an element in Group 18 of the periodic table, such as argon gas, an inert gas, such as nitrogen gas, hydrogen gas, and a mixed gas of hydrogen gas and argon gas.

[0049] The characteristic improvement effect of the annealing process is exhibited over a wide range of atmospheric pressures, from reduced pressure to pressurized pressure, but pressures lower than 1 kPa are not preferred because they accelerate the decomposition of the β-sialon phosphor. Furthermore, by pressurizing the atmosphere, it is possible to broaden the range of other conditions required to achieve the annealing effect (lower temperature, shorter time), but if the atmospheric pressure is too high, the annealing effect will plateau and a specialized and expensive annealing device will be required. Therefore, in consideration of mass productivity, the preferred atmospheric pressure is 10 MPa or less, and more preferably less than 1 MPa.

[0050] If the treatment time in the annealing step is too short, the effect of improving crystallinity is low, and if it is too long, the annealing effect reaches a plateau, so the treatment time is from 1 hour to 24 hours, preferably from 2 hours to 10 hours.

[0051] Furthermore, the manufacturing method of this embodiment may include an acid treatment step of immersing the β-sialon phosphor in an acid solution after the annealing step, which can further improve the properties of the phosphor.

[0052] The acid treatment step preferably includes a step of immersing the β-sialon phosphor in an acid solution, separating the β-sialon phosphor from the acid using a filter or the like, and washing the separated β-sialon phosphor with water. The acid treatment can remove decomposition products of the β-sialon phosphor crystals that occur during the annealing step, thereby improving the fluorescent properties. Examples of acids used in the acid treatment include hydrofluoric acid, sulfuric acid, phosphoric acid, hydrochloric acid, and nitric acid, either singly or in combination. A mixed acid consisting of hydrofluoric acid and nitric acid is preferred, as it is suitable for removing decomposition products. The temperature of the acid solution during the acid treatment may be room temperature, but it is preferable to heat it to between 50°C and 90°C to enhance the effectiveness of the acid treatment.

[0053] In the classification process, in order to remove fine powder from the powder after the acid treatment process, a decantation process is performed to remove fine powder from the supernatant liquid in which the powder after the acid treatment process is settling. The resulting precipitate is filtered, washed with ion-exchanged water or pure water, dried, and then passed through a sieve with a mesh size of 250 μm to obtain a β-sialon phosphor. An aqueous solution containing a dispersant such as sodium hexametaphosphate may be used as the dispersion medium. It is then preferable to wash with ion-exchanged water or pure water, filter, dry, and sieve the resulting mixture.

[0054] In this manner, a β-sialon phosphor containing an activator element in solid solution can be obtained. If necessary, additional known processes may be performed. For example, post-treatments such as crushing / disintegration, purification, drying, and sieving / classification may be performed. The particle size adjustment process, such as sieving / classification, may be performed at any time after the firing process, annealing process, or acid treatment process.

[0055] In the alkali treatment step, the β-sialon phosphor is heated in a state in which a solid basic substance is attached to the surface.

[0056] Examples of basic substances include alkali metal hydroxides, alkali metal carbonates, hydroxides of Group 2 elements of the periodic table, oxides of Group 2 elements of the periodic table, and quaternary ammonium salts. Examples of basic substances include NaOH, KOH, LiOH, CaO, SrO, Na ２ CO ３ , and NaHCO ３ The present invention includes one or more selected from the group consisting of:

[0057] The solid basic substance may be a basic substance that is solid at room temperature, or may be a basic solution prepared by dissolving a basic substance in a solvent such as water and then removing the solvent at a temperature below 50° C. to dry the basic substance. For example, the basic substance may be vacuum dried at a temperature below 50° C.

[0058] To attach a solid basic substance to the surface, for example, a powder of a β-sialon phosphor may be mixed with a basic substance that is solid at room temperature. Alternatively, a mixed solution containing a powder of a β-sialon phosphor, a basic substance, and water may be vacuum-dried at a temperature below 50°C to remove the water from the basic substance, thereby attaching the solid basic substance to the surface of the β-sialon phosphor. Removing a solvent such as water at a relatively low temperature below 50°C can suppress the formation of Si—OH groups on the surface of the β-sialon phosphor.

[0059] During the alkali treatment step, the β-sialon phosphor is heated with the solid basic substance attached to its surface in an environment substantially free of water. The substantially free of water means that moisture (humidity) contained in the exposure atmosphere outside the solid basic substance is allowed, or moisture in hydrates contained in the solid basic substance is allowed.

[0060] In the alkali treatment step, the β-sialon phosphor can be heated from room temperature. Room temperature may be, for example, 23° C. or 25° C. The upper limit of the heating temperature is not particularly limited, but may be, for example, 400° C. or lower, or 450° C. or lower.

[0061] In the alkali treatment step, heating may be performed from room temperature at a temperature rise rate of, for example, 0.1°C / min to 100°C / min, preferably 5°C / min to 50°C / min, and more preferably 1°C / min to 30°C / min.

[0062] In the alkali treatment step, the heating atmosphere may be, for example, an air atmosphere, a vacuum atmosphere, or an inert gas atmosphere such as a rare gas atmosphere or nitrogen atmosphere.

[0063] The method for producing a β-sialon phosphor according to this embodiment may further include a step of washing the resulting β-sialon phosphor with water after the alkali treatment step. The washing method involves stirring the β-sialon phosphor in ion-exchanged water or pure water for several minutes. After the mixture is left to stand, fine particles float on the water surface. The supernatant liquid is discarded along with the floating particles, and the precipitate is filtered. The cake of hydrated β-sialon phosphor (precipitate) is then added with ion-exchanged water and filtered to further remove basic substances, and the β-sialon phosphor is recovered. This process is repeated. It is recommended to perform the washing step two or more times. The washing step is repeated until the pH of the filtrate reaches 6 to 8. The amount of fine particles floating on the water surface during washing is greater in the second washing step than in the first washing step. The fine particles removed together with the supernatant liquid during washing are thought to contain impurities removed from the surface of the β-sialon phosphor during the alkali treatment step. When the fine powder removed together with the supernatant was analyzed, the FT-IR spectrum showed a wave number of 3530 cm －１ The peak of the Si-OH group near the peak is significantly high, and the surface composition analysis by XPS shows that B (boron) and F (fluorine) are significantly high. The water used for washing is removed by drying using a known method. After the alkali treatment step, post-treatments such as crushing / disintegration treatment, purification treatment, drying treatment, sieving / classification treatment, etc. may be carried out as necessary.

[0064] [Wavelength converter, light-emitting member] The light-emitting member of this embodiment includes a light-emitting element and a wavelength converter that converts light irradiated from the light-emitting element and emits light, and the wavelength converter has the above-mentioned β-sialon phosphor.

[0065] An example of the method for manufacturing a wavelength conversion member of the present embodiment includes a step of manufacturing a wavelength conversion member using a β-sialon phosphor obtained by the method for manufacturing a β-sialon phosphor.

[0066] The wavelength converter of this embodiment converts light irradiated from a light-emitting element to emit light, and includes the above-mentioned β-sialon phosphor. The wavelength converter may be composed only of the β-sialon phosphor, or may include a base material in which the β-sialon phosphor is dispersed. Known base materials can be used, such as glass, resin, and inorganic materials.

[0067] The shape of the wavelength converter is not particularly limited, and it may be configured in a plate shape, or may be configured to seal a part of the light emitting element or the entire light emitting surface.

[0068] [Light-emitting device] The light-emitting device according to this embodiment includes a light-emitting member including a light source (light-emitting element) and the wavelength converter. By combining the light source and the wavelength converter, it is possible to emit light with high luminous intensity.

[0069] An example of a method for manufacturing a light emitting device according to this embodiment includes a step of mounting a wavelength conversion member obtained by the method for manufacturing a wavelength conversion member on a light emitting surface of a light source.

[0070] An example of a light-emitting device is an LED package. The LED package may include a light source (LED chip), a substrate (lead frame) on which the light source is mounted, and a wavelength converter covering the light source. The LED chip may emit light with a wavelength of 300 nm to 500 nm, which is near-ultraviolet to blue light. 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.

[0071] The wavelength converter may contain the β-sialon phosphor, but may also contain other phosphors. Examples of other phosphors include an α-sialon phosphor, a KSF phosphor, a CASN phosphor, a SCASN phosphor, and a YAG phosphor. These phosphors may be used alone or in combination of two or more.

[0072] In the case of a light emitting device using the above-mentioned β-sialon phosphor, by irradiating near-ultraviolet light or visible light containing a wavelength of 300 nm or more and 500 nm or less as an excitation source, the light emits green light with a peak wavelength in the range of 520 nm or more and 560 nm or less. Therefore, by combining a near-ultraviolet LED chip or a blue LED chip and a β-sialon phosphor as a light source with one or more red-, blue-, yellow-, or orange-emitting phosphors, it is possible to produce white light.

[0073] For example, a combination of a β-sialon phosphor that exhibits green color and a KSF-based phosphor that exhibits red color can be used favorably in a backlight LED suitable for a high color rendering TV or the like.

[0074] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. within the scope of achieving the object of the present invention are included in the present invention. Below, an example of Reference Form P is added. 1. A β-type sialon phosphor in which europium is dissolved, and in the spectrum of the β-type sialon phosphor obtained by FT-IR, the absorbance of the spectrum is converted into a KM value using the Kubelka-Munk function, and the absorbance at a wave number of 3050 cm is obtained. －１ The KM value is E, and the wave number is 3330 cm －１ The KM value is F, and the wave number is 3500 cm －１ 1. A β-sialon phosphor having a structure in which E, F, and G satisfy 1.8<F / E and 1.8>G / E, where G is the KM value of the above formula. 2. A β-sialon phosphor having europium as a solid solution, wherein the absorbance of the spectrum of the β-sialon phosphor obtained by FT-IR is converted into a KM value by the Kubelka-Munk function, and the absorbance of the spectrum is converted into a KM value by the Kubelka-Munk function, where the absorbance of the spectrum is －１ The KM value is E, and the wave number is 3330 cm －１ The KM value is F, and the wave number is 3530 cm －１β-sialon phosphor configured so that E, F, and H satisfy 1.8<F / E and 2.0>H / E, where H is the KM value of the above. 3. A β-sialon phosphor according to 1., configured so that E, F, and G satisfy 1.8<F / E and 1.4>G / E. 4. A β-sialon phosphor according to 2., configured so that E, F, and H satisfy 1.8<F / E and 1.19>H / E. 5. A β-sialon phosphor containing europium as a solid solution according to any one of 1. to 4., wherein the amount of fluorine in the surface composition of the β-sialon phosphor is less than 0.4 atom %. 6. A β-sialon phosphor according to 1. to 5. 6. A β-sialon phosphor having europium dissolved therein as a solid solution, as set forth in any one of 1. to 5., wherein the amount of boron in the surface composition of the β-sialon phosphor is less than 0.5 atom %. 7. A light emitting member comprising: a light emitting element; and a wavelength converter that converts light irradiated from the light emitting element and emits light, wherein the wavelength converter has the β-sialon phosphor as set forth in any one of 1. to 6.. 8. A light emitting device comprising the light emitting element as set forth in 7. Below, examples of Reference Form Q are added. 1. A β-sialon phosphor having europium dissolved therein as a solid solution, wherein the spectrum of the β-sialon phosphor obtained by FT-IR after exposure for 1000 hours in an environment at a temperature of 85°C and a humidity of 85% is converted into a KM value using the Kubelka-Munk function, and the absorbance at a wavenumber of 3330 cm is －１ The KM value is A and the wave number is 3550 cm －１ 1. A β-sialon phosphor having a structure in which A and B satisfy 0.31>B / A, where B is the KM value of the above equation. 2. A β-sialon phosphor having europium dissolved therein, wherein the spectrum of the β-sialon phosphor obtained by FT-IR after exposure for 1000 hours in an environment of a temperature of 85°C and a humidity of 85% is converted from the absorbance of the spectrum to a KM value by the Kubelka-Munk function, and the absorbance at a wavenumber of 3330 cm is －１ The KM value is A and the wave number is 3500 cm －１3. A β-sialon phosphor in which europium is solid-solved, and in the spectrum of the β-sialon phosphor obtained by FT-IR after exposure for 1000 hours in an environment of a temperature of 85°C and a humidity of 85%, the absorbance of the spectrum is converted into a KM value by the Kubelka-Munk function, and the KM value at a wavenumber of 3330 cm is obtained. －１ The KM value is A and the wave number is 3600 cm －１ 3. A β-sialon phosphor having a structure in which A and D satisfy the relationship 0.21>D / A, where D is the KM value of the above equation. 4. A β-sialon phosphor having europium dissolved therein, wherein the spectrum of the β-sialon phosphor obtained by FT-IR after exposure for 1000 hours in an environment of a temperature of 85°C and a humidity of 85% is converted into a KM value by the Kubelka-Munk function, and the absorbance of the spectrum is found to be 0.21>D / A at a wavenumber of 3050 cm. －１ The KM value is L, and the wave number is 3330 cm －１ The KM value is A and the wave number is 3500 cm －１ 4. A β-sialon phosphor having a structure in which L, A, and C satisfy 1.4<A / L and 0.81>C / L, where C is the KM value of the above equation. 5. A β-sialon phosphor having europium as a solid solution, wherein the spectrum of the β-sialon phosphor obtained by FT-IR after exposure for 1000 hours in an environment of a temperature of 85°C and a humidity of 85% is converted from the absorbance of the spectrum to a KM value by the Kubelka-Munk function, and the absorbance at a wavenumber of 3050 cm is －１ The KM value is L, and the wave number is 3330 cm －１ The KM value is A and the wave number is 3530 cm －１6. A β-sialon phosphor configured so that L, A, and M satisfy 1.4<A / L and 0.67>M / L, where M is the KM value of the above formula. 6. The β-sialon phosphor according to 2., configured so that A and C satisfy 0.40>C / A. 7. A β-sialon phosphor containing europium as a solid solution, wherein the spectrum of the β-sialon phosphor obtained by FT-IR after exposure for 1000 hours in an environment at a temperature of 85°C and a humidity of 85% is converted from the absorbance of the spectrum to a KM value using the Kubelka-Munk function, and the absorbance at a wavenumber of 3050 cm is －１ The KM value is L, and the wave number is 3330 cm －１ The KM value of the above was designated as A. Next, in the spectrum of the β-sialon phosphor in which europium is dissolved before being exposed for 1000 hours in an environment of a temperature of 85°C and a humidity of 85%, obtained by FT-IR, the absorbance of the spectrum was converted into a KM value by the Kubelka-Munk function, and the KM value at a wave number of 3050 cm was determined. －１ The KM value is E, and the wave number is 3330 cm －１ where F is the KM value of the above formula, and L, A, E, and F are configured to satisfy 0.94 > ((A / L) / (F / E)). 8. A β-sialon phosphor having europium as a solid solution according to any one of 1. to 7., wherein the amount of fluorine in the surface composition of the β-sialon phosphor is less than 0.4 atom %. 9. A β-sialon phosphor having europium as a solid solution according to any one of 1. to 8., wherein the amount of boron in the surface composition of the β-sialon phosphor is less than 0.5 atom %. 10. A light emitting member comprising: a light emitting element; and a wavelength converter that converts light irradiated from the light emitting element and emits light, wherein the wavelength converter has the β-sialon phosphor according to any one of 1. to 9. A light emitting device comprising the light emitting member according to claim 1.

[0075] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the descriptions of these examples.

[0076] <Preparation of β-SiAlON Phosphor> [Comparative Example 1] (1) A container was filled with silicon nitride (Si ３ N ４ 98.4 mass % of aluminum nitride (AlN, E grade manufactured by Tokuyama Corporation), 1.01 mass % of europium oxide (Eu ２ O ３ Each raw material was weighed out so that the total amount of ruthenium dioxide (RU grade, manufactured by Shin-Etsu Chemical Co., Ltd.) was 0.59% by mass, and mixed using a V-type mixer (manufactured by Tsutsui Rikagaku Kikai Co., Ltd.) to obtain a mixture. The obtained mixture was passed through a sieve with a mesh size of 250 μm to remove aggregates, thereby obtaining a raw material composition. The aggregates that did not pass through the sieve were pulverized, and the particle size was adjusted so that they could pass through the sieve.

[0077] (2) 200 g of the raw material composition prepared as described above was weighed into a cylindrical boron nitride container with a lid (a molded product made by Denka Corporation, mainly composed of boron nitride (trade name: Denka Boron Nitride N-1), inner diameter: 10 cm, height: 10 cm). The container was then placed in an electric furnace equipped with a carbon heater, 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 (firing process). After heating, the sample that had become loosely agglomerated in the container was taken into a mortar and crushed. After crushing, the sample was passed through a sieve with a mesh size of 250 μm to obtain a powdery first sintered body.

[0078] (3) Next, the first fired body was packed into a cylindrical boron nitride container, and the container was placed in an electric furnace equipped with a carbon heater. The temperature was raised to 1450°C in an argon gas atmosphere (pressure: 0.025 MPaG), and heating was continued at 1450°C for 5 hours (annealing step). After heating, the loosely aggregated particles in the container were crushed in a mortar and mortar, and the powder was obtained by passing the particles through a 250 μm sieve.

[0079] (4) Next, the powder obtained in (3) was added to a mixed acid of hydrofluoric acid (concentration: 50% by mass) and nitric acid (concentration: 70% by mass) (a mixture of hydrofluoric acid and nitric acid in a volume ratio of 1:1), and acid treatment was performed for 30 minutes while stirring at a temperature of 75°C. After the acid treatment, the stirring was stopped, the powder was allowed to settle, and the supernatant and fine powder refined by the acid treatment were removed. Thereafter, further distilled water was added and the mixture was stirred again. The stirring was stopped, the powder was allowed to settle, and the supernatant and fine powder were removed. This operation was repeated until the pH of the aqueous solution was 8 or less and the supernatant liquid was transparent, and the resulting precipitate was filtered, dried, and passed through a sieve with 250 μm openings.

[0080] (5) Next, the powder obtained in (4) was dispersed in an aqueous solution of ion-exchanged water mixed with 0.05 wt% sodium hexametaphosphate as a dispersion medium to further remove fine particles, and the mixture was allowed to stand. A decantation process was then carried out to remove the fine particles from the supernatant liquid as they settled. The resulting precipitate was filtered, washed with ion-exchanged water, dried, and passed through a sieve with 250 μm openings. The decantation process was repeated. Thereafter, washing with ion-exchanged water, filtration, drying, and sieving were carried out. This resulted in the europium-activated β-sialon phosphor of Comparative Example 1.

[0081] Comparative Example 2 The β-sialon phosphor powder obtained in (5) in the same manner as in Comparative Example 1 was added to a mixed acid of hydrofluoric acid (concentration: 50% by mass) and nitric acid (concentration: 70% by mass) (a 1:1 volume ratio of hydrofluoric acid and nitric acid), and the mixture was stirred at 75°C for 30 minutes for acid treatment. After the acid treatment, the stirring was stopped, the powder was allowed to settle, and the supernatant and fine powder refined by the acid treatment were removed. Distilled water was then added and the mixture was stirred again. The stirring was stopped, the powder was allowed to settle, and the supernatant was removed. This procedure was repeated until the pH of the aqueous solution was 8 or less and the supernatant was transparent. The resulting precipitate was filtered, dried, and passed through a sieve with 250 μm openings, yielding the β-sialon phosphor of Comparative Example 2.

[0082] [Example 1] As in Comparative Example 1, the β-sialon phosphor powder obtained in (5) was mixed with a 50% by weight aqueous solution of sodium hydroxide. The resulting mixture was then filtered, and the residue was vacuum-dried at 45°C. The resulting dried powder was then heated in an alumina container in an air atmosphere from 25°C at a heating rate of 10°C / min to 175°C for 1 hour (alkali treatment step), followed by water washing. The water washing method involved stirring the β-sialon phosphor in ion-exchanged water for several minutes. After allowing the mixture to stand, fine particles floated on the water surface. The supernatant was discarded along with the floating fine particles, and the precipitate was filtered. The cake of hydrated β-sialon phosphor (precipitate) was then poured with ion-exchanged water and filtered to further remove basic substances, and the β-sialon phosphor was then recovered. The water washing was performed twice. The amount of fine particles floating on the water surface during the second water wash was greater than that during the first water wash. The fine powder removed together with the supernatant by water washing is thought to contain impurities removed from the surface of the β-sialon phosphor during the alkali treatment. When the fine powder removed together with the supernatant by water washing was analyzed, the FT-IR spectrum showed a wave number of 3530 cm －１ The peak of the Si—OH group near 0.05 was significantly high (higher than those of the samples of Example 1 and Comparative Example 1), and the surface composition analysis by XPS showed that B (boron) and F (fluorine) were significantly high (higher than those of the samples of Example 1 and Comparative Example 1). After washing with water, the phosphor was dried and passed through a sieve with an opening of 250 μm, thereby obtaining the europium-activated β-sialon phosphor of Example 1.

[0083] [Comparative Example 3] The β-sialon phosphor powder obtained in (5) in the same manner as in Comparative Example 1 was mixed with a 0.5% by mass aqueous solution of sodium hydroxide. The mixed solution was then placed in a polyethylene container, a lid was placed lightly on top so as not to completely seal the container, and the container was placed in a dryer set at 70°C for one hour. After filtration to remove the solvent, the β-sialon phosphor was stirred in ion-exchanged water for several minutes. The entire slurry, including the supernatant and floating fine powder, was filtered and recovered. The cake of hydrated β-sialon phosphor was then poured into ion-exchanged water and filtered to further remove basic substances. The process of recovering the β-sialon phosphor was repeated. The water wash was performed twice. After washing, the mixture was dried and passed through a 250 μm mesh sieve to obtain the β-sialon phosphor of Comparative Example 3.

[0084] [Comparative Example 4] The β-sialon phosphor powder obtained in (5) in the same manner as in Comparative Example 1 was mixed with a 0.5% by mass aqueous solution of sodium hydroxide. The mixed solution was then placed in a polyethylene container, lightly capped so as not to seal the container, and treated in a warm bath at 50°C for 30 minutes while stirring with a magnetic stirrer. It was then placed in a dryer set at 105°C for 30 minutes. After filtration to remove the solvent, the β-sialon phosphor was stirred in ion-exchanged water for several minutes. The entire slurry, including the supernatant and floating fine powder, was filtered and recovered. The cake of hydrated β-sialon phosphor was then poured into ion-exchanged water and filtered to further remove basic substances. The β-sialon phosphor was then recovered. The water washing was performed twice. After washing, the mixture was dried and passed through a 250 μm mesh sieve to obtain the β-sialon phosphor of Comparative Example 4.

[0085] Comparative Example 5: The β-sialon phosphor powder obtained in (5) was mixed with a 0.5% by mass aqueous solution of sodium hydroxide in the same manner as in Comparative Example 1. The mixture was stirred for 1 minute, filtered to remove the solvent, and then the β-sialon phosphor was stirred in ion-exchanged water for several minutes. The entire slurry, including the supernatant and any floating fine powder, was filtered and recovered. The cake of hydrated β-sialon phosphor was then poured into ion-exchanged water and filtered to further remove basic substances. This process of recovering the β-sialon phosphor was repeated. The water washing was performed twice. After washing, the mixture was vacuum dried at room temperature and passed through a sieve with a mesh size of 250 μm, yielding the β-sialon phosphor of Comparative Example 5.

[0086] [Comparative Example 6] A container was filled with silicon nitride (Si ３ N ４ 99.0 mass% of aluminum nitride (AlN, E grade manufactured by Tokuyama Corporation), 0.58 mass% of europium oxide (Eu ２ O ３ The raw materials were weighed out so that the content of 0.42 mass% of ruthenium dioxide (RU grade, manufactured by Shin-Etsu Chemical Co., Ltd.) was 0.42 mass%, and mixed in a V-type mixer (manufactured by Tsutsui Rikagaku Kikai Co., Ltd.). A β-sialon phosphor of Comparative Example 6 was obtained in the same manner as in Comparative Example 1, except that the conditions for obtaining the mixture were changed.

[0087] [Example 2] As in Comparative Example 6, the β-sialon phosphor powder obtained in (5) was mixed with a 50% by weight aqueous solution of sodium hydroxide. The resulting mixture was then filtered. The residue was vacuum-dried at 45°C to obtain a dried powder. The resulting powder was heated in an alumina container in an air atmosphere from 25°C at a heating rate of 10°C / min to 110°C for 1 hour (alkali treatment step), followed by water washing. The water washing method involved stirring the β-sialon phosphor in ion-exchanged water for several minutes. After leaving the mixture to stand, fine particles floated on the water surface. The supernatant was discarded along with the floating particles, and the precipitate was filtered. The cake of hydrated β-sialon phosphor (precipitate) was then added with ion-exchanged water and filtered to further remove basic substances. The β-sialon phosphor was then recovered. This procedure was repeated twice. After washing with water, the phosphor was dried and passed through a sieve with an opening of 250 μm to obtain a europium-activated β-sialon phosphor of Example 2.

[0088] [Example 3] As in Comparative Example 6, the β-sialon phosphor powder obtained in (5) was mixed with a 50% by weight aqueous solution of sodium hydroxide. The resulting mixture was then filtered. The residue was vacuum-dried at 45°C to obtain a dried powder. The resulting powder was heated in an alumina container in an air atmosphere from 25°C at a heating rate of 10°C / min to 175°C for 1 hour (alkali treatment step), followed by water washing. The water washing method involved stirring the β-sialon phosphor in ion-exchanged water for several minutes. After allowing the mixture to stand, fine particles floated on the water surface. The supernatant was discarded along with the floating particles, and the precipitate was filtered. The cake of hydrated β-sialon phosphor (precipitate) was then added with ion-exchanged water and filtered to further remove basic substances. The β-sialon phosphor was then recovered. This process was repeated twice. After washing with water, the phosphor was dried and passed through a sieve with an opening of 250 μm to obtain a europium-activated β-sialon phosphor of Example 3.

[0089] [Comparative Example 7] Silicon nitride (Si ３ N ４96.2 mass% of aluminum nitride (AlN, E grade manufactured by Tokuyama Corporation), 2.46 mass% of aluminum oxide powder (TM-DAR grade manufactured by Taimei Chemical Co., Ltd.), and 0.56 mass% of europium oxide (Eu ２ O ３ The raw materials were weighed out so that the content of 0.78 mass % of ruthenium dioxide (RU grade, manufactured by Shin-Etsu Chemical Co., Ltd.) was 0.78 mass %, and mixed in a V-type mixer (manufactured by Tsutsui Rikagaku Kikai Co., Ltd.). A β-sialon phosphor of Comparative Example 7 was obtained in the same manner as in Comparative Example 1, except that the conditions for obtaining the mixture were changed.

[0090] [Example 4] As in Comparative Example 7, the β-sialon phosphor powder obtained in (5) was mixed with a 50% by weight aqueous solution of sodium hydroxide. The resulting mixture was then filtered. The residue was vacuum-dried at 45°C to obtain a dried powder. The resulting powder was heated in an alumina container in an air atmosphere from 25°C at a heating rate of 10°C / min to 175°C for 1 hour (alkali treatment step), followed by water washing. The water washing method involved stirring the β-sialon phosphor in ion-exchanged water for several minutes. After allowing the mixture to stand, fine particles floated on the water surface. The supernatant was discarded along with the floating fine particles, and the precipitate was filtered. The cake of hydrated β-sialon phosphor (precipitate) was then added with ion-exchanged water and filtered to further remove basic substances. The β-sialon phosphor was then recovered. This procedure was repeated twice. After washing with water, the phosphor was dried and passed through a sieve with an opening of 250 μm to obtain a europium-activated β-sialon phosphor of Example 4.

[0091] (Measurement of FT-IR spectrum) The infrared absorption spectrum of the obtained β-sialon phosphor was determined by FT-IR, and the absorbance of the spectrum was converted into a KM value by the Kubelka-Munk function. The value of the Kubelka-Munk function (KM value of absorbance) and the wave number (cm －１ The KM-transformed spectrum showing the relationship between the KM and the IR spectra was obtained using a PerkinElmer Spectrum One (accessories: diffuse reflection, 64 integrations, resolution 4 cm). －１The FT-IR spectrum can be obtained by Fourier transform infrared spectroscopy (FT-IR) using AutoZero settings (normalization so that the lowest value of the spectrum after KM transformation is zero). Measurement sample P was a β-sialon phosphor before it was exposed for 1000 hours in an environment with 85% humidity. Measurement sample Q was a β-sialon phosphor after it was exposed for 1000 hours in an environment with a temperature of 85°C and a humidity of 85%. After the exposure, measurement sample Q was kept in an environment with a temperature of 15°C to 30°C and a humidity of 45 to 85% for 1 hour, then stored in a polyethylene bottle (hard bottle). Just before measurement, it was removed from the polyethylene bottle and its FT-IR spectrum was measured. Measurement samples P and Q were made by pelletizing undiluted β-sialon phosphor. In this specification, the "value of the Kubelka-Munk function" refers to a function that converts the reflectance of a substance into a value that serves as an index of the absorption specific to the substance, and can be obtained by dividing the extinction coefficient by the scattering coefficient (extinction coefficient / scattering coefficient).

[0092] In the KM converted spectrum of the measurement sample P, the wave number is 3050 cm －１ The KM value is E, and the wave number is 3330 cm －１ The KM value is F, and the wave number is 3500 cm －１ The KM value is G, and the wave number is 3530 cm －１ The KM value was set to H.

[0093] In the KM converted spectrum of the measurement sample Q, the wave number is 3330 cm －１ The KM value is A and the wave number is 3500 cm －１ The KM value is C and the wave number is 3550 cm －１ The KM value is B, and the wave number is 3600 cm －１ The KM value is D, and the wave number is 3050 cm －１ The KM value is L, and the wave number is 3530 cm －１ The KM value was defined as M.

[0094] In the measurement sample P, 3330 cm －１ is the NH group, 3500 cm －１ is the Si-OH group, 3530 cm －１ is the Si-OH group, 3050 cm －１ represents a valley portion where there are few absorbing components.－１ is the NH group, 3500 cm －１ is the Si-OH group, 3550 cm －１ is the Si-OH group, 3050 cm －１ is the valley where there is little absorption, 3530 cm －１ represents the Si-OH group. －１ Although the absorption is very small, some absorption due to Si-OH groups appears.

[0095] In each Example and Comparative Example using measurement sample Q, the values ​​of F / E, G / E, and H / E are shown in Table 1. In each Example and Comparative Example using measurement sample Q, the values ​​of B / A, C / A, D / A, A / L, C / L, M / L, and ((A / L) / (F / E)) are shown in Table 1.

[0096] 2, 3, and 4 show FT-IR spectra of measurement sample P of the β-sialon phosphor obtained in each example and comparative example at a wave number of 3050 cm before exposure at a temperature of 85° C. and a humidity of 85% for 1000 hours. －１ 5, 6, and 7 show FT-IR spectra of measurement sample P of the β-sialon phosphor obtained in each example and comparative example before exposure to a temperature of 85°C and a humidity of 85% for 1000 hours, at a wave number of 3330 cm. －１ 8, 9, and 10 show FT-IR spectra of measurement sample P of the β-sialon phosphor obtained in each example and comparative example before exposure to a temperature of 85°C and a humidity of 85% for 1000 hours.

[0097] 11, 12, and 13 show the FT-IR spectrum of the measurement sample Q of the β-sialon phosphor after exposure to a temperature of 85° C. and a humidity of 85% for 1000 hours, at a wave number of 3050 cm －１ 14, 15, and 16 show the FT-IR spectrum of the measurement sample Q of the β-sialon phosphor after exposure to a temperature of 85°C and a humidity of 85% for 1000 hours, at a wave number of 3330 cm. －１17, 18 and 19 show FT-IR spectra of measurement sample Q of the β-sialon phosphor after exposure to a temperature of 85° C. and a humidity of 85% for 1000 hours.

[0098] (Measurement of surface composition) The surface composition of measurement sample P of the β-sialon phosphor obtained in each example and comparative example before exposure for 1000 hours in an environment of 85% humidity was measured by X-ray photoelectron spectroscopy (XPS) under the following measurement conditions: Measurement device: X-ray photoelectron spectroscopy analyzer (PHI5000VersaProbeII manufactured by ULVAC-PHI, Inc.) Excitation source: Al-X-ray source (Al K Alpha) Output: 15 kV-50 W Measurement area: φ200 μm Pass energy: 46.95 eV Energy step size: 0.05 eV Time per step: 50 ms Number of scans: 10 Time: 13 min / point Remarks: Narrow scan, average of three measurements. The surface composition was analyzed so that the total of B, N, O, F, Na, Al, Si, and Eu was 100 atom % (carbon was excluded).

[0099]

[0100]

[0101]

[0102] The obtained β-sialon phosphor was evaluated for the following items.

[0103] <Particle Size> Using the measurement sample P of the β-sialon phosphor of each example, particle size was measured in accordance with the particle size distribution measurement method by laser diffraction / scattering described in JIS R 1629:1997 "Method for measuring particle size distribution by laser diffraction / scattering of fine ceramic raw materials." A particle size distribution measurement device (manufactured by Microtrac-Bell Corporation, product name: "Microtrac MT3300EX II") was used for the measurement. Specifically, 0.1 g of the phosphor to be measured was first added to 100 mL of ion-exchanged water, and the mixture was dispersed for 3 minutes using an ultrasonic homogenizer (manufactured by Nippon Seiki Seisakusho Co., Ltd., product name: "Ultrasonic Homogenizer US-150E", tip size: φ20, amplitude: 100%, oscillation frequency: 19.5 kHz, amplitude: approximately 31 μm) to prepare the measurement sample. The particle size was then measured using a particle size distribution analyzer. In the volume-based particle size distribution curve measured by the laser diffraction / scattering method, the particle sizes at which the integrated value from small particle sizes reached 10%, 50%, and 90% of the total were defined as D10, D50, and D90, respectively.

[0104] <Diffuse reflectance> Using measurement sample P of the β-sialon phosphor of each example, the diffuse reflectance was measured with an ultraviolet-visible spectrophotometer (V-550) manufactured by JASCO Corporation equipped with an integrating sphere device (ISV-469). Baseline correction was performed with a standard reflector (Spectralon), and a solid sample holder filled with the β-sialon phosphor was set, and the diffuse reflectance was measured in the wavelength range of 500 to 850 nm. The diffuse reflectance (%) at 500 nm and 800 nm was measured.

[0105] <Chromaticity X> Using the measurement sample P of the β-sialon phosphor of each example, chromaticity X was determined by calculating the CIE chromaticity coordinate x value (chromaticity X) in the XYZ color system defined in JIS Z8781-3:2016 from the spectral data in the wavelength range of 465 to 780 nm of the fluorescence spectrum in accordance with JIS Z8724:2015. The measurement method involved filling a concave cell with the phosphor to be measured so that the surface was smooth, and then attaching it to the opening of an integrating sphere. Monochromatic light, split into 455 nm wavelengths from a Xe lamp (light source), was introduced into the integrating sphere using an optical fiber as excitation light for the phosphor. This excitation light, or monochromatic light, was irradiated onto the phosphor to be measured, and the fluorescence spectrum was measured. A spectrophotometer (manufactured by Otsuka Electronics Co., Ltd., product name: MCPD-7000) was used for the measurement.

[0106] <Reliability Test> The reliability of the LED package incorporating the obtained β-SiAlON phosphor was evaluated as follows. An LED package was prepared according to the structure of the light-emitting device shown in Figure 1. First, the electrode on the top surface of the LED installed in the concave bottom of the case was wire-bonded to the lead frame. The LED used had an emission peak wavelength of 448 nm and a chip size of 1.0 mm x 0.5 mm. Next, a resin composition was obtained by mixing the β-SiAlON phosphor with a liquid silicone resin (KER6150, manufactured by Shin-Etsu Chemical Co., Ltd.) to a phosphor concentration of 10.5 wt%. The resulting resin composition was injected into the concave case using a microsyringe and left to stand for 15 hours in a room temperature, low humidity environment (MacDry MCU-201A, manufactured by ERC Co., Ltd.). It was then cured at 150°C for 1 hour. This resulted in an LED package incorporating the β-SiAlON phosphor. The luminous flux of the obtained LED package was measured, and the initial value was set to L0. Furthermore, the lamp was left for 500 hours at 85°C and 85% RH while being energized at 300 mA, and then removed and dried at room temperature. The luminous flux L1 was measured, and the reliability coefficient M (= L1 / L0 × 100) was calculated. The relative ratio of the reliability coefficients of Comparative Examples 2 to 5 and Example 1 is shown in Table 1, where the reliability coefficient M of Comparative Example 1 is set to 100.0%. The relative values ​​(%) of the reliability coefficients of Comparative Examples 2 to 5 and Example 1 are shown in Table 1. For example, if the reliability coefficient M of Comparative Example 1 is set to M1 and the reliability coefficient M of Example 1 is set to M2, the relative value of the reliability coefficient M of Example 1 is expressed as M2 / M1 × 100. The relative ratio of the reliability coefficients of Examples 2 and 3 is shown in Table 1, where the reliability coefficient M of Comparative Example 6 is set to 100.0%. The relative ratio of the reliability coefficient of Example 4, when the reliability coefficient M of Comparative Example 7 is set to 100.0%, is shown in Tables 1 and 2 as the relative value (%) of the reliability coefficient of Example 4, respectively.

[0107] The β-sialon phosphors of Examples 1 to 4 showed superior reliability in LED brightness when the LED was energized (continuously lit) in a high-temperature, high-humidity environment, compared to Comparative Examples 1 to 7.

[0108] This application claims priority based on Japanese Patent Application No. 2023-099450 filed on June 16, 2023, and Japanese Patent Application No. 2023-099451 filed on June 16, 2023, the disclosures of which are incorporated herein in their entireties.

[0109] REFERENCE SIGNS LIST 10 Light emitting device 20 Light emitting element 30 Heat sink 40 Case 50 First lead frame 60 Second lead frame 70 Bonding wire 72 Bonding wire 80 Composite 82 Alkali-treated phosphor particles 84 Sealant

Claims

1. A β-type sialon phosphor in which europium is dissolved, the spectrum of the β-type sialon phosphor obtained by FT-IR is converted into a KM value by the Kubelka-Munk function, and the absorbance of the spectrum is 3050 cm －１ The KM value is E, and the wave number is 3330 cm －１ The KM value is F and the wave number is 3500 cm －１ The KM value is G, and the wave number is 3530 cm －１ A β-SiAlON phosphor having at least one of the following (P1) and (P2), where H is the KM value of the above formula: (P1) E, F, and G satisfy 1.8<F / E and 1.8>G / E; and (P2) E, F, and H satisfy 1.8<F / E and 2.0>H / E.

2. A β-type sialon phosphor in which europium is dissolved, the spectrum of the β-type sialon phosphor obtained by FT-IR after exposure for 1000 hours in an environment of a temperature of 85°C and a humidity of 85%, the absorbance of the spectrum is converted to a KM value by the Kubelka-Munk function, and the wave number is 3330 cm －１ The KM value is A, and the wave number is 3550 cm －１ The KM value is B, and the wave number is 3500 cm －１ The KM value is C and the wave number is 3600 cm －１ The KM value is D, and the wave number is 3050 cm －１ The KM value is L, and the wave number is 3530 cm －１ The KM value of the above is defined as M. In the spectrum of the β-SiAlON phosphor obtained by FT-IR before exposure for 1000 hours under an environment of a temperature of 85° C. and a humidity of 85%, the absorbance of the spectrum is converted into a KM value by the Kubelka-Munk function, and the KM value is calculated by the following equation: －１ The KM value is E, and the wave number is 3330 cm －１ A β-sialon phosphor having at least one of the following (Q1) to (Q6), where F is the KM value of the phosphor. (Q1) A and B satisfy 0.31>B / A. (Q2) A and C satisfy 0.44>C / A. (Q3) A and D satisfy 0.21>D / A. (Q4) L, A and C satisfy 1.4<A / L and 0.81>C / L. (Q5) L, A and M satisfy 1.4<A / L and 0.67>M / L. (Q6) L, A, E and F satisfy 0.94>((A / L) / (F / E)).

3. A β-SiAlON phosphor according to claim 1 or 2, wherein the amount of fluorine in the surface composition of said β-SiAlON phosphor is less than 0.4 atom %.

4. A β-type sialon phosphor according to claim 1 or 2, wherein the amount of boron in the surface composition of said β-type sialon phosphor is less than 0.5 atom %.

5. A light-emitting component comprising: a light-emitting element; and a wavelength converter that converts light irradiated from the light-emitting element and emits light, wherein the wavelength converter has the β-sialon phosphor according to claim 1 or 2.

6. A light emitting device comprising the light emitting member according to claim 5.

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