JP2015224299A - Wavelength conversion member, light emitting device, and method of producing wavelength conversion member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion member having improved wavelength conversion efficiency.SOLUTION: A wavelength conversion member (1) comprises glass (10) having a softening point of 700°C or more, and one or plural kinds of phosphor particles (11) dispersed inside the glass (10). At least one kind of the phosphor particles (11) is covered with a coating layer comprising αSiAlON.

Description

  The present invention relates to a wavelength conversion member including a phosphor that converts excitation light into fluorescence, and a light emitting device including the wavelength conversion member.

  In recent years, a light emitting device in which a semiconductor light emitting element such as a light emitting diode (LED) is combined with a wavelength conversion member (for example, a member in which a phosphor is dispersed in a resin) has been developed. These light-emitting devices are advantageous in that they are small in size and consume less power than incandescent bulbs, and are used as light sources for various display devices or lighting devices.

  Patent Document 1 discloses a light emitting device that outputs pseudo white light. The light-emitting device is realized by combining (i) a blue LED and (ii) a phosphor that is excited by blue light from the blue LED and emits yellow light as a result of converting the wavelength of the blue light. . Patent Document 1 discloses three types of materials, ie, an epoxy resin, an acrylic resin, and water glass, as materials for dispersing phosphor particles.

  Recently, it has been studied to use a semiconductor laser or the like having a higher light density as a pumping light source for the above light emitting device than a blue LED or the like. In addition, it has been studied to use light having a shorter wavelength than blue light as excitation light.

  In this case, there is a problem that the resin that is a material for dispersing the phosphor is deteriorated by heat or light. In order to solve this problem, a technique using glass as a material for dispersing the phosphor has been proposed.

Patent Document 2 discloses a white illumination light source. The white illumination light source is composed of (i) a blue LED and (ii) a Y ₃ Al ₅ O ₁₂ (garnet) phosphor that is excited by light from the blue LED and emits yellow fluorescence. This is realized by combining a wavelength conversion member manufactured by being dispersed in glass having dots.

Patent Document 3 discloses an oxynitride glass (oxynitride glass) phosphor. The oxynitride glass is composed of CaCO ₃ , Al ₂ O ₃ , SiO ₂ , AlN, and rare earth oxide or transition metal oxide components.

In Patent Document 3, a rare earth element (Eu ²⁺ , Eu ³⁺ , Ce ³⁺ , Tb ^3+, etc.) that acts as an emission center or a transition metal element (Cr ³⁺ , Mn ^2+, etc.) that acts as an emission center is doped into glass. Shows that an oxynitride glass having strong emission intensity was obtained.

The manufacturing method of the oxynitride glass is as follows. First, CaCO ₃ , Al ₂ O ₃ , SiO ₂ , AlN, and Eu ₂ O ₃ are mixed in a ratio of 24.0: 3.3: 33.4: 33.3: 6.0.

  In a nitrogen atmosphere, the mixture is heated and melted at a temperature of 1700 ° C. for 2 hours using a high frequency furnace, and then rapidly cooled to obtain a fluorescent glass. The fluorescent glass is shown to emit red fluorescence upon receiving an excitation wavelength of about 500 nm. That is, the oxynitride glass of Patent Document 3 itself functions as a phosphor.

  However, since glass is amorphous, it does not have a certain atomic arrangement. Therefore, in the oxynitride glass of Patent Document 3, the atomic arrangement of the glass components around the rare earth atom that is the emission center changes due to changes in manufacturing conditions such as raw material ratio and processing temperature. For this reason, it is difficult to obtain a certain wavelength conversion efficiency (conversion efficiency of excitation light into fluorescence).

  In addition, the oxynitride glass has a problem in that the emission color changes depending on the manufacturing conditions, so that the reproducibility of fluorescence is poor, and the emission intensity of the rare earth element and the chromaticity of the emission color (that is, emission spectrum) change. is there. Further, the oxynitride glass has a low wavelength conversion efficiency as compared with an oxynitride phosphor described later.

  Patent Document 4 discloses a configuration in which an oxynitride phosphor or a nitride phosphor, which is a phosphor having high wavelength conversion efficiency and excellent heat resistance, is dispersed in a glass having a softening point of 700 ° C. or higher. Yes. In the said structure, since the fluorescent substance is excellent in heat resistance, the glass which has a relatively high softening point of 700 degreeC or more can be used.

  By using chemically stable glass having a softening point of 700 ° C. or higher, excitation light emitted from the semiconductor light emitting element is not absorbed by the glass, and light extraction efficiency from the phosphor is improved. For this reason, the wavelength conversion efficiency is improved, and as a result, a light emitting device having high light emission efficiency is realized.

Japanese Patent Laid-Open No. 10-163535 (released on June 19, 1998) JP 2003-258308 A (published September 12, 2003) Japanese Patent Laid-Open No. 2001-214162 (released on August 7, 2001) JP 2007-16171 A (released on January 25, 2007)

  However, none of the above-described prior art documents disclose or suggest that the wavelength conversion efficiency of the wavelength conversion member can be sufficiently improved. Therefore, there is a problem that it is impossible to realize a wavelength conversion member with improved wavelength conversion efficiency than before.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a wavelength conversion member with improved wavelength conversion efficiency than before.

  In order to solve the above-described problem, a wavelength conversion member according to one embodiment of the present invention includes a glass having a softening point of 700 ° C. or higher, and 1 that emits fluorescence in response to excitation light dispersed inside the glass. And at least one of the phosphor particles is covered with a coating layer containing αSiAlON.

  In order to solve the above-described problem, a method for manufacturing a wavelength conversion member according to one embodiment of the present invention includes glass having a softening point of 700 ° C. or higher, and one or more types that emit fluorescence by receiving excitation light. A method of manufacturing a wavelength conversion member comprising: a phosphor layer, wherein at least one of the phosphor particles is coated with a coating layer containing αSiAlON; and the phosphor particles Is dispersed in the inside of the glass.

  According to the wavelength conversion member concerning one mode of the present invention, there is an effect that the wavelength conversion efficiency of a wavelength conversion member can be improved rather than before. Moreover, according to the manufacturing method of the wavelength conversion member which concerns on 1 aspect of this invention, there exists an effect that the wavelength conversion member which improved the wavelength conversion efficiency conventionally can be manufactured.

It is a figure which shows schematic structure of the wavelength conversion member which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the structure of the light-emitting device provided with the wavelength conversion member which concerns on Embodiment 1 of this invention. It is a figure which shows the emission spectrum in one Example which concerns on Embodiment 1 of this invention. It is a figure which shows the emission spectrum in the one comparative example which concerns on Embodiment 1 of this invention. It is a figure which shows the emission spectrum in one Example which concerns on Embodiment 2 of this invention. It is a figure which shows the emission spectrum in one comparative example which concerns on Embodiment 2 of this invention. It is a figure which shows the emission spectrum in one Example which concerns on Embodiment 3 of this invention. It is a figure which shows the emission spectrum in one comparative example which concerns on Embodiment 3 of this invention. It is a figure which shows the value of the chromaticity point of the wavelength conversion member which concerns on each Example of this invention, and each comparative example, color temperature, and a light beam.

Embodiment 1
Embodiment 1 of the present invention will be described below with reference to FIGS. 1 to 4 and FIG. 9.

(Wavelength conversion member 1)
FIG. 1 is a diagram showing a schematic structure of the wavelength conversion member 1. The wavelength conversion member 1 includes glass 10 and phosphor particles 11. As will be described later, the wavelength conversion member 1 is manufactured by dispersing phosphor particles 11 in glass 10.

  In the wavelength conversion member 1, the softening point of the glass 10 is 700 ° C. or higher. The phosphor particles 11 are composed of one type or two or more types of phosphor particles. As will be described later, at least one type of phosphor particle 11 is coated (coated) with a coating layer containing αSiAlON.

(Glass 10)
The glass 10 is a chemically stable glass having a softening point of 700 ° C. or higher. With respect to glass, various temperatures such as a transition point, a softening point, and a melting point are defined. In the present embodiment, attention is mainly focused on the softening point of glass.

  The softening point of the glass corresponds to the lower limit value of the temperature in the process of dispersing the phosphor particles 11 in the glass 10. The glass softening point is defined as the temperature of the glass when the viscosity of the glass is 1E + 7.6 dPa · s.

  As the glass 10, oxide-based glass such as silica glass or oxynitride glass is preferably used. The softening point of oxynitride glass is generally about 850 to 1000 ° C., although it depends on the composition. The softening point of silica glass is about 1700 ° C.

  Oxynitride glass is particularly suitable as the glass 10 because of its high refractive index. For example, as the glass 10, an oxynitride glass having a composition of Ca—Si—Al—O—N can be applied.

  Further, as the glass 10, Ca—Mg—Si—Al—O—N, La—Si—O—N, Mg—Si—O—N, Y—Al—Si—O—N, Mg—Si—Al— ON, Na-Si-ON, Na-Ca-Si-ON, Li-K-Al-Si-ON, Na-B-Si-ON, Ba-Al-Si- An oxynitride glass having a composition such as O—N, Na—B—O—N, Li—P—O—N, or Na—P—O—N may be applied.

Generally, as a raw material of oxynitride glass, a metal oxide such as SiO ₂ and a metal nitride or metal oxynitride as a nitrogen supply source are used. As the metal oxide other than _{SiO 2, Al 2 O 3,} BaO, Sb 2 O 3, SrO, Na 2 O, Na 2 O 3, CaO, MgO, K 2 O, La 2 O 3, CeO 2 Y ₂ O ₃ , ZrO ₂ , ZnO ₂ , As ₂ O ₃ , TiO ₂ , B ₂ O ₃ , Cr ₂ O ₃ , PbO, V ₂ O ₅ , and SnO ₂ .

Further, carbonates, hydroxides, oxalates, and the like that become these metal oxides by thermal decomposition may be blended as raw materials. Examples of the metal nitride include Si ₃ N ₄ , AlN, Al ₂ N ₂ , Mg ₂ N ₂ , and Li ₃ N. Examples of the metal oxynitride include Si ₂ N ₂ O and Si ₅ N ₆ O.

  The temperature at which the wavelength conversion member 1 is manufactured (formed) may be 700 ° C. or higher. However, in the manufacture of the wavelength conversion member 1, it is necessary to suppress the reaction of the phosphor particles 11 (for example, oxynitride phosphor particles or nitride phosphor particles) and prevent melting.

  Considering this, it is preferable that the temperature at which the wavelength conversion member 1 is manufactured is lower by 50 ° C. or more than the firing temperature of the phosphor. Moreover, it is more preferable that the temperature when the wavelength conversion member 1 is manufactured is a temperature lower by 200 ° C. or more than the firing temperature of the phosphor.

  As described above, the oxynitride glass has a softening point of about 850 to 1000 ° C. Therefore, when oxynitride glass is used as the glass 10, by heating a mixture of fine glass powder and phosphor powder obtained by pulverizing oxynitride glass at a temperature equal to or higher than the softening point of the oxynitride glass. The wavelength conversion member 1 in which the phosphor particles 11 are dispersed almost uniformly in the glass 10 can be manufactured.

  In production of the wavelength conversion member 1, it can be said that a higher heating temperature is preferable in order to improve work efficiency. However, from the viewpoint of preventing the phosphor particles 11 from being decomposed, the heating temperature is preferably 1600 ° C. or lower.

  By the way, as described above, silica glass has a relatively high softening point compared to oxynitride glass. For this reason, when silica glass is used as the glass 10, the phosphor particles 11 are decomposed when a mixture of fine glass powder and phosphor powder obtained by pulverizing silica glass is heated at a temperature equal to or higher than the softening point of the glass 10. there's a possibility that.

  Therefore, when silica glass is used as the glass 10, it is preferable to manufacture the glass 10 by using a sol-gel method using a metal alkoxide as a raw material. By manufacturing the glass 10 using the sol-gel method, the wavelength conversion member 1 in which the phosphor particles 11 are dispersed almost uniformly in the glass 10 can be manufactured at a relatively low temperature of 1200 ° C. or less.

(Phosphor particles 11)
As described above, the phosphor particles 11 are composed of one kind or two or more kinds of phosphors. And at least 1 type of fluorescent substance particle 11 is coat | covered with the coating layer containing (alpha) SiAlON.

  In the process of dispersing the phosphor particles 11 in the glass 10, damage to the phosphor particles 11 is reduced by covering the phosphor particles 11 with a coating layer containing αSiAlON which is thermally and chemically stable.

  The wavelength conversion member 1 manufactured in this way has higher wavelength conversion efficiency of the phosphor particles than the conventional wavelength conversion member. Therefore, according to the wavelength conversion member 1, more efficient fluorescence can be obtained compared with the conventional wavelength conversion member.

  Here, in order to improve the stability of the coating layer, the thickness of the coating layer is preferably 10 nm or more. In order to further improve the stability of the coating layer, the thickness of the coating layer is more preferably 100 nm or more. Moreover, in order to suppress the coarsening of the phosphor particles 11 coated with the coating layer, the thickness of the coating layer is preferably set to 100 μm or less.

  Therefore, the thickness of the coating layer may be determined as an appropriate value within the range of 10 nm or more and 100 μm or less. In addition, as described above, the thickness of the coating layer is more preferably set to an appropriate value within the range of 100 nm or more and 100 μm or less.

As the material of the phosphor particles 11, a known phosphor material is preferably used. Specific examples of the phosphor material include an aluminate-based phosphor such as Ce-activated Y ₃ (Al, Ga) ₅ O ₁₂ , a silicate-based phosphor such as Eu-activated (Ba, Sr) ₂ SiO ₄ , and Eu-activated αSiAlON. Phosphor, Eu-activated βSiAlON phosphor, Ce-activated αSiAlON phosphor, Ce-activated βSiAlON phosphor, Ce-activated JEM phosphor, oxynitride phosphor such as Ce-activated CALSON phosphor, Eu-activated CaAlSiN ₃ phosphor, Eu-activated M Examples include phosphor materials such as nitride phosphors such as ₂ Si ₅ N ₈ phosphor (M = Ca, Ba, Sr), and Ce activated La ₃ Si ₆ N ₁₁ phosphor.

  In the wavelength conversion member 1 of the present embodiment, in order to disperse the phosphor particles 11 in the glass 10 having a relatively high softening point of 700 ° C. or higher, conventional wavelength conversion in which the phosphor particles are dispersed in a resin such as silicone. It is preferable to use a more chemically stable phosphor material than in the case of the member.

  Therefore, among the phosphor materials described above, it is particularly preferable to use an oxynitride phosphor or a nitride phosphor excellent in heat resistance.

(Light Emitting Device 100)
FIG. 2 is a cross-sectional view illustrating a configuration of the light emitting device 100 including the wavelength conversion member 1. The light emitting device 100 includes a wavelength conversion member 1, a substrate 22, and a nitride laser 23 (excitation light source).

  The nitride laser 23 includes an n-type electrode 23A and a p-type electrode 23B. The substrate 22 includes an electrode 24A, an electrode 24B, and a support portion 25. In the light emitting device 100, the wavelength conversion member 1 is bonded onto the support portion 25 provided on the substrate 22.

  The nitride laser 23 is a semiconductor laser element made of InGaAlN-based crystal. The nitride laser 23 is disposed on the substrate 22. The n-type electrode 23 A of the nitride laser 23 is electrically connected to the electrode 24 A on the substrate 22. The p-type electrode 23B of the nitride laser 23 is electrically connected to the electrode 24B on the substrate 22.

  The nitride laser 23 emits excitation light 26 toward the wavelength conversion member 1. The excitation light 26 excites the phosphor particles 11 dispersed inside the wavelength conversion member 1. As a result, fluorescence 27 having a wavelength longer than that of the excitation light 26 is emitted from the phosphor particles 11. Thus, the wavelength conversion member 1 has a function of converting the excitation light 26 into the fluorescence 27 (that is, converting the wavelength of the light).

  In the following description of the present embodiment, the case where the emission peak wavelength of the excitation light 26 is 405 nm or 450 nm will be exemplified. However, the emission peak wavelength of the excitation light 26 may be changed in the range of 300 nm or more and 500 nm or less by appropriately adjusting the composition of the constituent materials such as the light emitting layer of the nitride laser 23.

  Moreover, the chromaticity of the light (illumination light) emitted from the light emitting device 100 can be changed by appropriately adjusting the mixing ratio of the phosphor particles 11 in the wavelength conversion member 1. For example, the light emitting device 100 that emits white light as illumination light can be manufactured by synthesizing the emission colors of the fluorescence emitted from the respective phosphors. The light emitting device 100 that emits white light as illumination light is particularly suitable for use as an illumination light emitting device.

  Further, by adjusting the dispersion composition of each phosphor, (i) a cold-color illumination light-emitting device close to the emission color of the fluorescent lamp, or (ii) a warm-color illumination light-emitting device close to the light emission color of the light bulb As described above, the light emitting device 100 that emits white light can be manufactured.

  In addition, since the luminous efficiency of each phosphor may change depending on the production lot or the like, the mixing ratio of the phosphor particles 11 needs to be appropriately adjusted according to the specifications of the light emitting device 100.

  As described above, the emission peak wavelength of the nitride laser 23 may be 300 nm or more and 500 nm or less. However, the emission peak wavelength of the nitride laser 23 is more preferably 350 nm or more and 420 nm or less.

  This is because the wavelength region of 350 nm or more and 420 nm or less substantially corresponds to the wavelength region where the peak of the excitation spectrum (excitation wavelength dependence of wavelength conversion efficiency) of the oxynitride phosphor or nitride phosphor can be obtained. is there. For this reason, high wavelength conversion efficiency is obtained in the wavelength region.

  Furthermore, another reason is that light in the wavelength region has low visibility. For this reason, in the light emitting device 100, there is an advantage that the color variation of the illumination light due to the variation in the emission peak wavelength of the nitride laser 23 hardly occurs.

  Conventionally, when excitation light having a short wavelength of 350 nm or more and 420 nm or less is used, there has been a problem that ultraviolet rays are deteriorated in the phosphor itself or a resin in which the phosphor is dispersed.

  However, the glass 10 contained in the wavelength conversion member 1 of the present embodiment is a chemically stable glass having a softening point of 700 ° C. or higher, and does not absorb light in the wavelength region from violet light to ultraviolet light. (Translucent). For this reason, the ultraviolet degradation of the glass 10 can be suppressed.

  “The glass 10 has translucency” means “in the wavelength region of 350 nm or more and 800 nm or less, the light transmittance including the surface reflection loss in the sample of the glass 10 having a thickness of 1 mm or more is 90%. It may be understood to mean “the above”.

  Furthermore, the use of an oxynitride phosphor or a nitride phosphor particularly excellent in chemical stability as the material of the phosphor particles 11 included in the wavelength conversion member 1 makes it preferable to deteriorate the phosphor particles 11 with ultraviolet rays. Can be suppressed.

  Thus, since the ultraviolet-ray deterioration of the wavelength conversion member 1 can be suppressed, the long-life light-emitting device 100 which could not be realized conventionally can be realized. Specifically, the light emitting device 100 can be realized as a light emitting device in which the change in luminous intensity is within 3% even after an operation time of 3000 hours.

(Production example of phosphor particles 11)
Hereinafter, Production Examples 1 to 4 as production examples of the phosphor particles 11 will be described. Comparative production examples 1 and 2 as comparative examples of production examples 1 to 4 will also be described.

(Production Example 1: Production of Eu-activated αSiAlON phosphor)
Preparation Example 1, the composition formula _{(Ca x, Eu y)} in _{(Si 12- (m + n)} Al m + n) (O n N 16-n), x = 1.8, y = 0.075, m = 3. This is a manufacturing process aimed at obtaining a phosphor of 75, n = 0.05.

  First, composition of α-type silicon nitride powder 59.8 mass%, aluminum nitride powder 24.3% mass, calcium nitride powder 13.9 mass%, europium oxide powder 0.9 mass%, europium nitride powder 1.1 mass% The raw material powder was weighed so that The europium nitride powder used was synthesized by nitriding metal europium in ammonia.

  Next, the raw material powder was mixed for 10 minutes or more using a mortar and pestle made of a silicon nitride sintered body to obtain a powder aggregate. Next, the obtained powder aggregate was passed through a sieve having an opening of 250 μm and filled in a boron nitride crucible having a diameter of 20 mm and a height of 20 mm. The powder weighing, mixing, and forming steps were all performed in a glove box capable of maintaining a nitrogen atmosphere with a moisture content of 1 ppm or less and oxygen of 1 ppm or less.

  Next, the crucible was set in a graphite resistance heating type pressure electric furnace, and nitrogen having a purity of 99.999 deposition% was introduced into the pressure electric furnace, the pressure was set to 1 MPa, and the temperature was 500 ° C. per hour. The pressurizing electric furnace was heated up to 1800 ° C. according to the increasing rate.

  Subsequently, in the pressurized electric furnace, the temperature of 1800 ° C. was maintained for 2 hours, and the powder aggregate was subjected to heat treatment. The product obtained by the heat treatment was pulverized with an agate mortar and treated at a temperature of 60 ° C. in a 1: 1 mixed acid of 50% hydrofluoric acid and 70% nitric acid to obtain a phosphor powder. .

  As a result of powder X-ray diffraction measurement (XRD, X-Ray Diffraction) using Cu Kα ray on the obtained phosphor powder, it was confirmed that the phosphor powder has a structure of αSiAlON crystal. We were able to. Moreover, as a result of irradiating the phosphor powder with light from a lamp emitting light having a wavelength of 365 nm as excitation light, it was confirmed that orange fluorescence was emitted from the phosphor powder.

(Comparative Production Example 1: Production of Eu-activated βSiAlON phosphor)
In Comparative Production Example 1, in the composition formula Si _{6-z ′} Al _{z ′} O _{z ′} N _{8−z ′} , Eu is 0.10 at. This is a manufacturing process aiming at obtaining a% activated Eu-activated βSiAlON phosphor.

  First, the raw material powder was weighed so that the metal Si powder passed through a 45 μm sieve had a composition of 93.59 wt%, aluminum nitride powder 5.02 wt%, and europium oxide powder 1.39 wt%. .

  Next, using a mortar and pestle made of a silicon nitride sintered body, mixing was performed for 10 minutes or more to obtain a powder aggregate. Then, the powder aggregate was naturally dropped into a boron nitride crucible having a diameter of 20 mm and a height of 20 mm.

  Next, the crucible was set in a pressure electric furnace using a graphite resistance heating method. And in the said pressurization electric furnace, the baking atmosphere was made into vacuum with the diffusion pump, and it heated up by the temperature increase rate of 500 degreeC per hour from room temperature to 800 degreeC. Then, the pressure was set to 0.5 MPa by introducing nitrogen having a purity of 99.999% by volume at 800 ° C. And it heated up to 1300 degreeC with the temperature increase rate of 500 degreeC per hour. Thereafter, the temperature was raised to 1600 ° C. at a temperature increase rate of 1 ° C. per minute, and the temperature of 1600 ° C. was maintained for 8 hours. The synthesized sample was pulverized into powder with an agate mortar to obtain a powder sample.

  Next, these powders were reheated. First, the powder fired at 1600 ° C. was pulverized using a silicon nitride mortar and pestle. Then, the powder was naturally dropped into a crucible made of boron nitride having a diameter of 20 mm and a height of 20 mm.

  Next, the crucible was set in a pressure electric furnace using a graphite resistance heating method. And in the said pressurization electric furnace, the baking atmosphere was made into vacuum with the diffusion pump, and it heated with the temperature increase rate of 500 degreeC per hour from room temperature to 800 degreeC. Then, nitrogen having a purity of 99.999% by volume was introduced at 800 ° C. to make the pressure 1 MPa. And it heated up to 1900 degreeC with the temperature increase rate of 500 degreeC per hour, and kept the temperature of 1900 degreeC over 8 hours. As a result, a phosphor sample was obtained.

  Then, the obtained phosphor sample was pulverized with an agate mortar, and further treated in a 1: 1 mixed acid of 50% hydrofluoric acid and 70% nitric acid at a temperature of 60 ° C. to thereby obtain a phosphor powder. Obtained.

  As a result of performing powder X-ray diffraction measurement on the phosphor powder, it was confirmed that the phosphor powder had a β-type SiAlON structure. Moreover, as a result of irradiating the phosphor powder with light from a lamp emitting light having a wavelength of 365 nm as excitation light, it was confirmed that green fluorescence was emitted from the phosphor powder.

(Production Example 2: Production of Eu-activated βSiAlON phosphor coated with αSiAlON)
Production Example 2 was coated with Ca-added αSiAlON (composition formula Ca _0.8 Si _9.6 Al _2.4 O _0.8 N _15.2 ) expressed as m = 1.6 and n = 0.8. In addition, this is a manufacturing process aimed at obtaining an Eu-activated βSiAlON phosphor.

  First, by using ammonia as a catalyst in ethanol, high-purity alkoxysilane was synthesized by a sol-gel method to obtain a spherical amorphous silicon dioxide powder having an average particle size of 0.1 μm. And the said powder was added in the aqueous solution containing Ca and Al, and citric acid was added, stirring and mixing.

  By this operation, Ca and Al citrate was adsorbed on the silicon dioxide surface, and then heated with stirring to remove moisture and dried. The citrate was then converted to oxide by heating to 700 ° C. in air. The obtained calcined product was loosened with an agate mortar to obtain powdered αSiAlON precursor compound particles.

  Next, the precursor compound particles, Eu-activated βSiAlON phosphor particles obtained in Comparative Production Example 1 described above, and ethanol as a solvent were prepared. Then, 7.7 g of the precursor compound particles and 87.5 ml of ethanol were placed in a beaker, and the precursor compound particles were dispersed in ethanol by applying ultrasonic waves. Then, after adding 25 g of Eu-activated βSiAlON phosphor particles in ethanol, the precursor compound particles were dispersed by further applying ultrasonic waves to obtain a slurry.

  While stirring the obtained slurry with a stirrer, spray drying was performed by a spray drying method at a spraying temperature of 100 ° C. to 200 ° C. with a nitrogen flow rate of 350 L / hour (phosphor particle coating step). In addition, as a spray dryer, spray dryer B-290 (made by Nihon Buchi Co., Ltd.) was used.

  Thus, a powder mixture in which Eu-activated βSiAlON phosphor particles were coated with αSiAlON precursor compound particles was produced. Further, about 2 g of the body mixture was filled in a boron nitride crucible having a diameter of 20 mm and a height of 20 mm.

  Then, the crucible was set in a graphite electric heating type pressure electric furnace. Then, nitrogen having a purity of 99.999 deposit% was introduced into the pressurized electric furnace to make the pressure 1 MPa, and the temperature was raised to 1800 ° C. at a temperature increase rate of 500 ° C. per hour. And the temperature of 2000 degreeC was hold | maintained over 2 hours, and the heat processing was performed. The product obtained by the heat treatment was pulverized by an agate mortar and treated at a temperature of 60 ° C. in a 1: 1 mixed acid of 50% hydrofluoric acid and 70% nitric acid to thereby coat Eu coated with αSiAlON. Activated βSiAlON phosphor (hereinafter referred to as αSiAlON-coated Eu activated βSiAlON phosphor) particles were obtained.

  As a result of observation by SEM (Scanning Electron Microscope) / EDX (Energy Dispersive X-ray spectrometry) on the cross section of the obtained αSiAlON-coated Eu activated βSiAlON phosphor particles, the surface of the Eu activated βSiAlON phosphor was found to be αSiAlON. It was confirmed that the film was covered with a coating layer having a thickness of about 1 μm.

(Production Example 3: Production of Ce-activated αSiAlON phosphor)
Production Example 3, a composition formula _{(Ca x, Ce y)} in _{(Si 12- (m + n)} Al m + n) (O n N 16-n), x = 0.5, y = 0.1, m = 1. 6. This is a manufacturing process aimed at obtaining a phosphor with n = 0.8.

  First, the raw material powder is weighed so as to have a composition of α-type silicon nitride powder 71.06% by mass, aluminum nitride powder 15.17% by mass, calcium carbonate powder 7.92% by mass, and cerium oxide powder 5.45% by mass. did. And the powder aggregate was obtained by mixing raw material powder for 10 minutes or more using the mortar and pestle made from a silicon nitride sintered compact.

  Next, the obtained powder aggregate was passed through a sieve having an opening of 250 μm and filled in a boron nitride crucible having a diameter of 20 mm and a height of 20 mm. The powder weighing, mixing, and forming steps were all performed in a glove box capable of maintaining a nitrogen atmosphere with a moisture content of 1 ppm or less and oxygen of 1 ppm or less.

  Next, the crucible was set in a pressure electric furnace using a graphite resistance heating method. Then, nitrogen having a purity of 99.999 deposit% was introduced into the pressurized electric furnace to make the pressure 1 MPa, and the temperature was raised to 1800 ° C. at a temperature increase rate of 500 ° C. per hour. And the temperature of 1800 degreeC was hold | maintained over 2 hours, and the heat processing was performed. And the product obtained by heat processing is grind | pulverized with an agate mortar, Furthermore, it processed at the temperature of 60 degreeC in the 1: 1 mixed acid of 50% hydrofluoric acid and 70% nitric acid, and fluorescent substance powder Got.

  The obtained phosphor powder was subjected to powder X-ray diffraction measurement using Cu Kα rays. As a result, it was confirmed that the phosphor powder had a structure of αSiAlON crystal. Moreover, as a result of irradiating the phosphor powder with light from a lamp emitting light having a wavelength of 365 nm as excitation light, it was confirmed that blue-green fluorescence was emitted from the phosphor powder.

(Comparative Production Example 2: Production of Eu-activated CaAlSiN ₃ phosphor)
Comparative production example 2 is a production process aimed at obtaining a phosphor of the composition formula Ca _0.992 Eu _0.008 SiAlN ₃ .

  First, 29.7 mass% of aluminum nitride powder, 33.9 mass% of α-type silicon nitride powder, 35.6 mass% of calcium nitride powder, and 0.8 mass% of europium nitride powder were weighed. And these powders were mixed for 10 minutes or more using the mortar and pestle made from a silicon nitride sintered compact, and the powder aggregate was obtained. The europium nitride used was synthesized by nitriding metal europium in ammonia.

  Next, the powder aggregate was naturally dropped into a boron nitride crucible having a diameter of 20 mm and a height of 20 mm. The powder weighing, mixing, and forming steps were all performed in a glove box capable of maintaining a nitrogen atmosphere with a moisture content of 1 ppm or less and oxygen of 1 ppm or less.

  Next, the crucible was set in a pressure electric furnace using a graphite resistance heating method. Then, nitrogen having a purity of 99.999% by volume was introduced into the pressurized electric furnace to make the pressure 1 MPa, and the temperature was increased to 1800 ° C. at a temperature increase rate of 500 ° C. per hour. A phosphor sample was obtained by maintaining a temperature of 1800 ° C. for 2 hours. And the fluorescent substance powder was obtained by grind | pulverizing the obtained fluorescent substance sample with an agate mortar.

As a result of performing powder X-ray diffraction measurement using Cu Kα ray on the phosphor powder, it was confirmed that the phosphor powder had a structure of CaAlSiN ₃ crystal. Moreover, as a result of irradiating the phosphor powder with light from a lamp emitting light having a wavelength of 365 nm as excitation light, it was confirmed that red fluorescence was emitted from the phosphor powder.

(Production Example 4: Production of Eu-activated CaAlSiN ₃ phosphor coated with αSiAlON)
Production Example 4 is a production process aimed at producing Eu-activated CaAlSiN ₃ coated with αSiAlON. Production Example 4 is a production example substantially similar to Production Example 2 described above.

Specifically, Production Example 4 is the same as Production Example 2 except that the phosphor is Eu-activated CaAlSiN ₃ produced in Comparative Production Example 2 described above. Thus, in Production Example 4, Eu activated CaAlSiN ₃ phosphor coated with ArufaSiAlON (hereinafter, referred to as ArufaSiAlON coating Eu activated CaAlSiN ₃ phosphor) was manufactured particles.

As a result of cross-sectional SEM / EDX observation of the obtained αSiAlON-coated Eu-activated CaAlSiN ₃ phosphor particles, it was confirmed that the surface of the Eu-activated CaAlSiN ₃ phosphor was coated with a coating layer having a thickness of about 1 μm containing αSiAlON. I was able to confirm.

(Manufacture of wavelength conversion member 1)
Hereinafter, Examples G1 to G3 as production examples of the wavelength conversion member 1 will be described. Further, Comparative Examples G1 to G3 as comparative examples of Examples G1 to G3 will also be described.

(Example G1)
For the production of the wavelength conversion member in Example G1, (i) Eu-activated αSiAlON phosphor and αSiAlON-coated Eu-activated βSiAlON phosphor were applied as the phosphor particles 11, and (ii) oxynitride glass was applied as the glass 10, respectively. .

  Specifically, after producing the oxynitride glass, the wavelength conversion member in which the phosphor particles 11 are dispersed in the glass 10 by mixing and melting the fine powder of the oxynitride glass and the phosphor particles. Was made.

First, SiO ₂ (30.4% by weight), Al ₂ O ₃ (3.0% by weight), AlN (2.4% by weight), Si ₃ N ₄ (26.4% by weight) which are raw materials for oxynitride glass. %), CaO (34.9% by weight), and MgO (2.9% by weight) powders were mixed to prepare a mixed powder.

  And after filling the said mixed powder into the crucible, the said crucible was put into the electric furnace. Next, the electric furnace is evacuated by exhausting from the exhaust port using a vacuum pump. Then, after closing the exhaust port, nitrogen having a purity of 99.9% by volume is introduced from the gas introduction port, and the exhaust port is opened when the pressure reaches normal pressure.

  By the above procedure, the electric furnace was brought to normal pressure in dry nitrogen and heated to 1600 ° C. And after hold | maintaining the temperature of 1600 degreeC for 2 hours, the oxynitride glass was obtained by quenching rapidly.

  The oxynitride glass raw material is melted, for example, at a temperature of 1400 ° C. to 1900 ° C. for 3 hours to 100 hours in an inert gas atmosphere not containing oxygen such as nitrogen or argon. preferable.

  Next, the obtained oxynitride glass was pulverized into glass fine powder. And glass fine powder and fluorescent substance powder were mixed. Specifically, the phosphor powder was mixed at a weight ratio of 6.3% by weight with respect to the glass fine powder. And the mixture was shape | molded by the hot press method, and the molded object was obtained.

  Here, the phosphor powder of Example G1 comprises (i) the Eu-activated αSiAlON phosphor manufactured in the above-described Production Example 1, and (ii) the αSiAlON-coated Eu-activated βSiAlON phosphor produced in Production Example 2. 11:12 by weight ratio.

  Next, the obtained molded body is heated by raising the temperature of the electric furnace to 1200 ° C. in a dry atmosphere / normal pressure. Then, after maintaining the temperature of 1200 ° C. for 2 hours and then rapidly cooling, a wavelength conversion unit in which the phosphor powder was dispersed almost uniformly in the oxynitride glass was manufactured (phosphor particle dispersion step) ).

(Comparative Example G1)
In the production of the wavelength conversion member in Comparative Example G1, (i) Eu-activated αSiAlON phosphor and Eu-activated βSiAlON phosphor were applied as phosphor particles 11, and (ii) oxynitride glass was applied as glass 10, respectively.

  In Comparative Example G1, a glass fine powder of oxynitride glass was prepared by the same method as in Example G1, and then the phosphor powder was used in a weight ratio of 5.3% by weight with respect to the glass fine powder. Mixed.

  Here, the phosphor powder of Comparative Example G1 includes (i) an Eu-activated αSiAlON phosphor manufactured in the above-described Production Example 1, and (ii) an Eu-activated βSiAlON phosphor produced in Comparative Production Example 1. It is a mixture by weight ratio of 24:29.

  The mixing ratio of each phosphor in Comparative Example G1 is adjusted so that the volume ratio of each phosphor (portion excluding the coating layer) to glass is the same as that in Example G1.

  And the mixture was shape | molded by the hot press method, and the wavelength conversion member by which the fluorescent substance particle was disperse | distributed substantially uniformly in the oxynitride glass was manufactured by the process similar to Example G1.

(Example G2)
In the production of the wavelength conversion member in Example G2, (i) Ce-activated αSiAlO phosphor and αSiAlON-coated Eu-activated CaAlSiN ₃ phosphor were applied as the phosphor particles 11, and (ii) oxynitride glass was applied as the glass 10, respectively. .

  In Example G2, glass fine powder of oxynitride glass was prepared by the same method as in Example G1, and then phosphor powder was mixed with the glass fine powder at a weight ratio of 5.5%. did.

Here, the phosphor powder of Example G2 includes (i) a Ce-activated αSiAlON phosphor manufactured in the above-described Production Example 3, and (ii) an αSiAlON-coated Eu-activated CaAlSiN ₃ phosphor produced in Production Example 4. Are mixed at a weight ratio of 47: 8.

  And the mixture was shape | molded by the hot press method, and the wavelength conversion member by which the fluorescent substance particle was disperse | distributed substantially uniformly in the oxynitride glass was manufactured by the process similar to Example G1.

(Comparative Example G2)
For the production of the wavelength conversion member in Comparative Example G2, (i) Ce-activated αSiAlO phosphor and Eu-activated CaAlSiN ₃ phosphor were applied as the phosphor particles 11, and (ii) oxynitride glass was applied as the glass 10, respectively.

  In Comparative Example G2, a glass fine powder of oxynitride glass was prepared by the same method as in Example G1, and then the phosphor powder was used in a weight ratio of 5.3% by weight with respect to the glass fine powder. Mixed.

Here, the phosphor powder of Comparative Example G2 includes (i) the Eu-activated αSiAlON phosphor manufactured in the above-described Production Example 1, and (ii) the Eu-activated CaAlSiN ₃ phosphor produced in the Comparative Production Example 2. , 47: 6.

  The mixing ratio of each phosphor in Comparative Example G2 is adjusted so that the volume ratio of each phosphor (portion excluding the coating layer) to glass is the same as that in Example G2.

  And the mixture was shape | molded by the hot press method, and the wavelength conversion member by which the fluorescent substance particle was disperse | distributed substantially uniformly in the oxynitride glass was manufactured by the process similar to Example G1.

(Example G3)
For the production of the wavelength conversion member in Example G3, (i) Eu-activated αSiAlON phosphor and αSiAlON-coated Eu-activated βSiAlON phosphor were applied as the phosphor particles 11, and (ii) silica glass was applied as the glass 10, respectively.

  In Example G3, a material in which phosphor powder is dispersed in silica glass is produced by a sol-gel method using metal alkoxide as a raw material.

  First, tetramethoxysilane (TMOS), dimethylformamide (DMF), methanol, pure water, and ammonium hydroxide were mixed with TMOS: DMF: methanol: pure water: ammonium hydroxide = 1: 1: 2: 12: 0. A mixed solution is prepared by mixing to a molar ratio of .0005.

  And after mixing phosphor powder 0.19g in the said mixed solution 20g, the fluorescent substance dispersion | distribution wet gel was obtained by stirring at room temperature for 1 hour. Then, the obtained phosphor-dispersed wet gel is put into a dryer while being transferred to a container having a desired shape.

  Next, in a dryer, after maintaining the temperature of 35 ° C. for 8 hours, the temperature is raised to 80 ° C. over 24 hours. And after hold | maintaining the temperature of 80 degreeC for 120 hours, it heats up again to 150 degreeC. And the above-mentioned fluorescent substance dispersion | distribution wet gel was dried by hold | maintaining the temperature of 150 degreeC for 96 hours. As a result, a phosphor-dispersed dry gel having a desired shape was obtained.

  Next, the phosphor-dispersed and dried gel was put into a firing furnace, and the temperature was raised from room temperature to 1050 ° C. over 52 hours. And the said phosphor dispersion | distribution dry gel was vitrified by hold | maintaining the temperature of 1050 degreeC over 2 hours. As a result, a wavelength conversion member in which the phosphor powder was dispersed almost uniformly in silica glass was formed.

  Here, the phosphor powder of Example G3 comprises (i) the Eu-activated αSiAlON phosphor manufactured in the above-described Production Example 1, and (ii) the αSiAlON-coated Eu-activated βSiAlON phosphor produced in Production Example 2. , 13:21 by weight ratio.

(Comparative Example G3)
For the production of the wavelength conversion member in Comparative Example G3, (i) Eu-activated αSiAlON phosphor and Eu-activated βSiAlON phosphor were applied as phosphor particles 11, and (ii) silica glass was applied as glass 10.

  In Comparative Example G3, tetramethoxysilane (TMOS), dimethylformamide (DMF), methanol, pure water, and ammonium hydroxide were mixed at the same mixing ratio as in Example G3 above to prepare a mixed solution. .

  Then, 0.16 g of the phosphor powder is mixed in 20 g of the mixed solution, and the wavelength conversion member in which the phosphor powder is dispersed almost uniformly in the silica glass using the sol-gel method in the same manner as in Example G3 described above. Was made.

  Here, the phosphor powder of Comparative Example G3 includes (i) the Eu-activated αSiAlON phosphor manufactured in the above-described Production Example 1, and (ii) the Eu-activated βSiAlON phosphor produced in Comparative Production Example 1. It is mixed at a weight ratio of 13:16.

  The mixing ratio of each phosphor in Comparative Example G3 is adjusted so that the volume ratio of each phosphor (portion excluding the coating layer) to glass is the same as that in Example G3.

(Performance evaluation of wavelength conversion member of this embodiment)
Next, the performance of the wavelength conversion member 1 was evaluated using the light emitting device 100 shown in FIG. Hereinafter, Example D1 which shows the evaluation result of the wavelength conversion member of this embodiment is demonstrated. A comparative example D1 as a comparative example of Example D1 will also be described.

(Example D1)
In Example D1, the wavelength conversion member obtained in Example G1 described above was employed as the wavelength conversion member included in the light emitting device 100.

  Specifically, the wavelength conversion member obtained in Example G1 was processed into a disk shape having a diameter of 5 mm and a thickness of 1 mm using a diamond cutter and a sandpaper. Then, the light emitting device 100 was manufactured by attaching the wavelength conversion member to the support portion 25 of the light emitting device 100. The emission peak wavelength of the nitride laser 23 was set to 450 nm.

  FIG. 3 is a graph showing the results of measuring the emission spectrum of the illumination light emitted from the light emitting device 100 in Example D1 using a spectral radiance meter MCPD-7000 (manufactured by Otsuka Electronics Co., Ltd.).

  In FIG. 3, the horizontal axis of the graph represents the wavelength (nm) of illumination light. The vertical axis of the graph represents the emission intensity (arbitrary unit) of illumination light. The horizontal axis and the vertical axis of the graph are the same in FIGS. 4 to 8 described later.

  As a result of analyzing the emission spectrum of the illumination light shown in FIG. 3, the color temperature of the illumination light was 5087K. Further, the chromaticity point of the illumination light was (CIEx, CIEy) = (0.343, 0.351).

  Further, under the driving condition in which the energy of the excitation light emitted from the nitride laser 23 is 200 mW, the light emitting device 100 is driven, and the total luminous flux of the illumination light is measured by a measurement system using MCPD-7000 and an integrating sphere. . As a result, it was confirmed that the total luminous flux of the illumination light was 30.9 lm.

(Comparative Example D1)
In Comparative Example D1, the wavelength conversion member obtained in Comparative Example G1 described above was employed as the wavelength conversion member included in light emitting device 100.

  Specifically, in the same manner as in Example D1 described above, the wavelength conversion member obtained in Comparative Example G1 was processed into a disk shape having a diameter of 5 mm and a thickness of 1 mm to manufacture the light emitting device 100. Also, the emission peak wavelength of the nitride laser 23 was set to 450 nm as in Example D1.

  FIG. 4 is a graph showing a result of measuring an emission spectrum of illumination light emitted from the light emitting device 100 in Comparative Example D1 using a spectral radiance meter MCPD-7000.

  As a result of analyzing the emission spectrum of the illumination light shown in FIG. 4, the color temperature of the illumination light was 2880K. The chromaticity point of the illumination light was (CIEx, CIEy) = (0.418, 0.352).

  Also, comparing FIG. 3 with FIG. 4, it is understood that the emission intensity at the emission peak wavelength of Comparative Example D1 is significantly smaller than the emission intensity at the emission peak wavelength of Example D1.

  Further, under the driving condition in which the energy of the excitation light emitted from the nitride laser 23 is 200 mW, the light emitting device 100 is driven, and the total luminous flux of the illumination light is measured by a measurement system using MCPD-7000 and an integrating sphere. . As a result, it was confirmed that the total luminous flux of the illumination light was 17.6 lm.

  Moreover, when the excitation light conversion efficiency in the light-emitting device of Example D1 described above was 100%, it was confirmed that the excitation light conversion efficiency in the light-emitting device of Comparative Example D1 was 58%.

(Effect of wavelength conversion member of this embodiment)
FIG. 9 is a table showing the color temperature, chromaticity point, and luminous flux value of illumination light in each of the above-described Example D1, Comparative Example D1, and Examples D2 to D3 and Comparative Examples D2 to D3 described later. is there.

  As shown in FIG. 9, in Example D1, the color temperature of the illumination light is obtained as daylight white color around 5000K. On the other hand, in Comparative Example D1, although the volume ratio of the phosphor particles to the glass (oxynitride glass) that is the dispersant of the wavelength conversion member is the same as that of the wavelength conversion member of Example D1, the illumination light The color temperature was around 3000K.

  That is, in Comparative Example D1, a color temperature greatly deviating from daylight white was obtained. Further, as described above, it was confirmed that the excitation light conversion efficiency in Comparative Example D1 was significantly lower than that in Example D1.

  The difference between Example D1 and Comparative Example D1 (which may be understood as the difference between Example G1 and Comparative Example G1) is that the phosphor particles contained in the wavelength conversion member are thermally and chemically. This is caused by whether or not it is covered with a coating layer containing stable αSiAlON.

  Specifically, in Comparative Example D1, the Eu-activated βSiAlON phosphor is not covered with a coating layer containing αSiAlON. For this reason, in the comparative example G1, in the process of manufacturing the wavelength conversion member, the Eu-activated βSiAlON phosphor particles deteriorate.

  On the other hand, in Example D1, the Eu activated βSiAlON phosphor is covered with a coating layer containing αSiAlON. For this reason, in Example G1, deterioration of Eu activated βSiAlON phosphor particles is suppressed in the process of manufacturing the wavelength conversion member.

  Thereby, according to the wavelength conversion member of Example D1, high wavelength conversion efficiency is realizable compared with the wavelength conversion member of comparative example D1. Therefore, by using the wavelength conversion member of Example D1, it is possible to realize a light emitting device having higher light emission efficiency than conventional ones.

  Note that βSiAlON emits green fluorescence with high human visibility. For this reason, the luminous flux of the light-emitting device greatly decreases due to the degradation of βSiAlON. Therefore, in the light emitting device of Example D1, the Eu-activated βSiAlON phosphor is covered with the coating layer containing αSiAlON, so that a light flux having a value significantly larger than that of the light emitting device of Comparative Example D1 is obtained.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIGS. 5 to 6 and FIG. 9. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

(Performance evaluation of wavelength conversion member of this embodiment)
In the second embodiment, the performance of the wavelength conversion member 1 was evaluated in the same manner as in the first embodiment. Here, Example D2 which shows the evaluation result of the wavelength conversion member of this embodiment is demonstrated. A comparative example D2 as a comparative example of the example D2 will also be described.

(Example D2)
In Example D2, the wavelength conversion member obtained in Example G2 described above was adopted as the wavelength conversion member included in the light emitting device 100.

  Specifically, the light-emitting device 100 was manufactured by processing the wavelength conversion member obtained in Example G2 into a disk shape having a diameter of 5 mm and a thickness of 1 mm in the same manner as Example D1 described above. The emission peak wavelength of the nitride laser 23 was set to 410 nm.

  FIG. 5 is a graph showing the results of measuring the emission spectrum of the illumination light emitted from the light emitting device 100 in Example D2 using a spectral radiance meter MCPD-7000.

  As a result of analyzing the emission spectrum of the illumination light shown in FIG. 5, the color temperature of the illumination light was 2830K. Further, the chromaticity point of the illumination light was (CIEx, CIEy) = (0.451, 0.411).

  Further, under the driving condition in which the energy of the excitation light emitted from the nitride laser 23 is 200 mW, the light emitting device 100 is driven, and the total luminous flux of the illumination light is measured by a measurement system using MCPD-7000 and an integrating sphere. . As a result, it was confirmed that the total luminous flux of the illumination light was 20.5 lm.

(Comparative Example D2)
In Comparative Example D2, the wavelength conversion member obtained in Comparative Example G2 described above was employed as the wavelength conversion member included in light emitting device 100.

  Specifically, in the same manner as in Example D1 described above, the wavelength conversion member obtained in Comparative Example G2 was processed into a disk shape having a diameter of 5 mm and a thickness of 1 mm to manufacture the light emitting device 100. The emission peak wavelength of the nitride laser 23 was set to 405 nm.

  FIG. 6 is a graph showing the results of measuring the emission spectrum of the illumination light emitted from the light emitting device 100 in Comparative Example D2 using a spectral radiance meter MCPD-7000.

  As a result of analyzing the emission spectrum of the illumination light shown in FIG. 6, the color temperature of the illumination light was 7691K. The chromaticity point of the illumination light was (CIEx, CIEy) = (0.267, 0.416).

  Also, comparing FIG. 5 with FIG. 6, it is understood that the emission intensity at the emission peak wavelength of Comparative Example D2 is significantly smaller than the emission intensity at the emission peak wavelength of Example D2.

  Further, under the driving condition in which the energy of the excitation light emitted from the nitride laser 23 is 200 mW, the light emitting device 100 is driven, and the total luminous flux of the illumination light is measured by a measurement system using MCPD-7000 and an integrating sphere. . As a result, it was confirmed that the total luminous flux of the illumination light was 9.5 lm.

  Further, when the excitation light conversion efficiency in the light emitting device of Example D2 was set to 100%, it was confirmed that the excitation light conversion efficiency in the light emitting device of Comparative Example D2 was 62%.

(Effect of wavelength conversion member of this embodiment)
As shown in FIG. 9, in Example D2, the color temperature of the illumination light is obtained as a light bulb color near 2800K. On the other hand, in Comparative Example D2, the volume ratio of the phosphor particles to the glass (oxynitride glass) that is the dispersant of the wavelength conversion member is the same as that of the wavelength conversion member of Example D2, but the illumination light The color temperature was around 7600K.

  That is, in Comparative Example D2, a color temperature greatly deviating from the light bulb color was obtained. Further, as described above, it was confirmed that the excitation light conversion efficiency in Comparative Example D2 was significantly lower than that in Example D2.

In Comparative Example D2, the Eu activated CaAlSIN ₃ phosphor is not covered with a coating layer containing αSiAlON. For this reason, in the comparative example D2, in the process of manufacturing the wavelength conversion member, the Eu activated CaAlSIN ₃ phosphor particles deteriorate.

On the other hand, in Example D2, the Eu-activated CaAlSIN ₃ phosphor is covered with a coating layer containing αSiAlON. For this reason, in Example D2, deterioration of Eu activated CaAlSIN ₃ phosphor particles is suppressed in the process of manufacturing the wavelength conversion member.

  Thereby, also by the wavelength conversion member of Example D2, high wavelength conversion efficiency is realizable like the wavelength conversion member of Example D1. Therefore, by using the wavelength conversion member of Example D2, it is possible to realize a light-emitting device having higher light emission efficiency than before. In addition, according to the light emitting device of Example D2, it is possible to obtain a light flux having a larger value than the conventional one.

[Embodiment 3]
The following will describe another embodiment of the present invention with reference to FIGS. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

(Performance evaluation of wavelength conversion member of this embodiment)
In the third embodiment, the performance of the wavelength conversion member 1 was evaluated in the same manner as in the first and second embodiments. Here, Example D3 which shows the evaluation result of the wavelength conversion member of this embodiment is demonstrated. A comparative example D3 as a comparative example of the example D3 will also be described.

(Example D3)
In Example D3, the wavelength conversion member obtained in Example G3 described above was employed as the wavelength conversion member included in the light emitting device 100.

  Specifically, the light-emitting device 100 was manufactured by processing the wavelength conversion member obtained in Example G3 into a disk shape having a diameter of 5 mm and a thickness of 1 mm in the same manner as Example D1 described above. The emission peak wavelength of the nitride laser 23 was set to 405 nm.

  FIG. 7 is a graph showing the results of measuring the emission spectrum of the illumination light emitted from the light emitting device 100 in Example D3 using a spectral radiance meter MCPD-7000.

  As a result of analyzing the emission spectrum of the illumination light shown in FIG. 7, the color temperature of the illumination light was 4892K. The chromaticity point of the illumination light was (CIEx, CIEy) = (0.348, 0.353).

  Further, under the driving condition in which the energy of the excitation light emitted from the nitride laser 23 is 200 mW, the light emitting device 100 is driven, and the total luminous flux of the illumination light is measured by a measurement system using MCPD-7000 and an integrating sphere. . As a result, it was confirmed that the total luminous flux of the illumination light was 30.9 lm.

(Comparative Example D3)
In Comparative Example D3, the wavelength conversion member obtained in Comparative Example G3 described above was employed as the wavelength conversion member included in the light emitting device 100.

  Specifically, in the same manner as in Example D1 described above, the wavelength conversion member obtained in Comparative Example G3 was processed into a disk shape having a diameter of 5 mm and a thickness of 1 mm to manufacture the light emitting device 100. Also, the emission peak wavelength of the nitride laser 23 was set to 405 nm as in Example D1.

  FIG. 8 is a graph showing the results of measuring the emission spectrum of the illumination light emitted from the light emitting device 100 in Comparative Example D3 using a spectral radiance meter MCPD-7000.

  As a result of analyzing the emission spectrum of the illumination light shown in FIG. 8, the color temperature of the illumination light was 2862K. Further, the chromaticity point of the illumination light was (CIEx, CIEy) = (0.422, 0.359).

  Also, comparing FIG. 7 with FIG. 8, it is understood that the emission intensity at the emission peak wavelength of Comparative Example D3 is significantly smaller than the emission intensity at the emission peak wavelength of Example D3.

  Further, under the driving condition in which the energy of the excitation light emitted from the nitride laser 23 is 200 mW, the light emitting device 100 is driven, and the total luminous flux of the illumination light is measured by a measurement system using MCPD-7000 and an integrating sphere. . As a result, it was confirmed that the total luminous flux of the illumination light was 18.5 lm.

  Moreover, when the excitation light conversion efficiency in the light-emitting device of Example D3 described above was 100%, it was confirmed that the excitation light conversion efficiency in the light-emitting device of Comparative Example D3 was 61%.

(Effect of wavelength conversion member of this embodiment)
As shown in FIG. 9, in Example D3, the color temperature of the illumination light is obtained as a daylight white color around 5000K. On the other hand, in Comparative Example D3, although the volume ratio of the phosphor particles to the glass (silica glass) that is the dispersant of the wavelength conversion member is the same as that of the wavelength conversion member of Example D3, the color temperature of the illumination light Was around 2800K.

  That is, in Comparative Example D3, a color temperature greatly deviating from daylight white was obtained. Further, as described above, it was confirmed that the excitation light conversion efficiency in Comparative Example D3 was significantly lower than that in Example D3.

  In Comparative Example D3, the Eu-activated βSiAlON phosphor is not covered with a coating layer containing αSiAlON. For this reason, in Comparative Example D3, the Eu-activated βSiAlON phosphor particles deteriorate in the process of manufacturing the wavelength conversion member.

  On the other hand, in Example D3, the Eu-activated βSiAlON phosphor is covered with a coating layer containing αSiAlON. For this reason, in Example D3, deterioration of Eu activated βSiAlON phosphor particles is suppressed in the process of manufacturing the wavelength conversion member.

  Thereby, also by the wavelength conversion member of Example D3, high wavelength conversion efficiency is realizable like the wavelength conversion member of Examples D1 and D2. Therefore, by using the wavelength conversion member of Example D3, it is possible to realize a light-emitting device having higher light emission efficiency than before. In addition, according to the light emitting device of Example D3, it is possible to obtain a light flux having a larger value than the conventional one.

[Embodiment 4]
In each of the above-described embodiments, only the Eu-activated βSiAlON phosphor or the Eu-activated CaAlSIN ₃ phosphor is not covered with the coating layer containing αSiAlON. Therefore, in each of the above-described embodiments, the Eu-activated αSiAlON phosphor is not covered with a coating layer containing αSiAlON.

  However, the Eu activated αSiAlON phosphor may also be coated with a coating layer containing αSiAlON. Thereby, the stability of the Eu activated αSiAlON phosphor can be improved.

However, the degree of improvement in stability when the Eu-activated αSiAlON phosphor is coated with a coating layer containing αSiAlON is determined when the Eu-activated βSiAlON phosphor or the Eu-activated CaAlSIN ₃ phosphor is coated with a coating layer containing αSiAlON. On the other hand, the inventors of the present application have found that it is relatively small.

  For this reason, in each above-mentioned embodiment, it does not illustrate about the composition which coats Eu activation alpha SiAlON fluorescent substance with the coating layer containing alpha SiAlON.

[Summary]
The wavelength conversion member (1) according to the first aspect of the present invention receives a glass (10) having a softening point of 700 ° C. or higher and fluorescence (27) upon receiving excitation light (26) dispersed inside the glass. And at least one of the phosphor particles is covered with a coating layer containing αSiAlON.

  According to said structure, the glass which has a softening point of a comparatively high temperature of 700 degreeC or more by coat | covering the at least 1 sort (s) of fluorescent substance particle with the coating layer containing (alpha) SiAlON which is thermally and chemically stable. In the process of dispersing the phosphor particles (process for producing the wavelength conversion member), it is possible to suppress the deterioration of the phosphor particles.

  Therefore, there is an effect that the wavelength conversion efficiency of the wavelength conversion member can be improved as compared with the conventional one.

  In the wavelength conversion member according to aspect 2 of the present invention, in the aspect 1, it is preferable that the at least one type of phosphor particles is an oxynitride phosphor or a nitride phosphor.

  According to said structure, in the process which manufactures a wavelength conversion member by using the oxynitride fluorescent substance or nitride fluorescent substance which is a fluorescent material excellent in heat resistance, suitably suppresses deterioration of fluorescent substance particles. There is an effect that can be done.

In the wavelength conversion member according to aspect 3 of the present invention, in the aspect 2, the at least one kind of phosphor particles is preferably a βSiAlON phosphor or a CaAlSiN ₃ phosphor.

According to the above configuration, the phosphor particles is βSiAlON phosphor, or by using a CaAlSiN ₃ phosphor is (ii) nitride phosphor, the phosphor particles are (i) oxynitride phosphor There exists an effect that degradation can be controlled suitably.

  In the wavelength conversion member according to aspect 4 of the present invention, in any one of the above aspects 1 to 3, the thickness of the coating layer is preferably 10 nm or more and 100 μm or less.

  According to said structure, while ensuring stability of a coating layer, there exists an effect that the coarsening of the fluorescent substance particle coat | covered with the coating layer can be suppressed.

  In the wavelength conversion member according to aspect 5 of the present invention, in the aspect 4, the thickness of the coating layer is preferably 100 nm or more and 100 μm or less.

  According to said structure, while improving stability of a coating layer, there exists an effect that the coarsening of the fluorescent substance particle coat | covered with the coating layer can be suppressed.

  In the wavelength conversion member according to aspect 6 of the present invention, in any one of the above aspects 1 to 5, the peak wavelength of the excitation light is preferably 300 nm or more and 500 nm or less.

  According to said structure, there exists an effect that a fluorescent substance particle can be excited suitably.

  In the wavelength conversion member according to aspect 7 of the present invention, in the aspect 6, the peak wavelength of the excitation light is preferably 350 nm or more and 420 nm or less.

  According to said structure, when an oxynitride fluorescent substance or nitride fluorescent substance is applied as a fluorescent substance particle, there exists an effect that the said fluorescent substance particle can be excited suitably.

  Further, glass having a softening point of 700 ° C. or higher has a property (translucency) that is chemically stable and does not absorb light in a wavelength region from violet light to ultraviolet light. For this reason, according to the wavelength conversion member which concerns on 1 aspect of this invention, the advantage that the ultraviolet-ray deterioration of glass by excitation light is suppressed is also acquired.

  In the wavelength conversion member according to aspect 8 of the present invention, in any one of the above aspects 1 to 7, the glass is preferably oxynitride glass.

  According to said structure, the process which manufactures a wavelength conversion member can be performed by comparatively low temperature by applying the oxynitride glass which has a softening point low compared with a silica glass. For this reason, there exists an effect that deterioration of fluorescent substance particles can be controlled suitably.

  In the wavelength conversion member according to aspect 9 of the present invention, in any one of the above aspects 1 to 7, the glass may be silica glass.

  According to said structure, there exists an effect that a wavelength conversion member can be manufactured using the silica glass which is one of chemically stable glass.

  A light emitting device according to aspect 10 of the present invention includes a wavelength conversion member according to any one of aspects 1 to 9, an excitation light source (nitride laser 23) that irradiates the wavelength conversion member with the excitation light. Are preferably provided.

  According to said structure, there exists an effect that the light-emitting device excellent in light emission efficiency compared with the former can be implement | achieved by using the wavelength conversion member which has wavelength conversion efficiency.

  Moreover, the manufacturing method of the wavelength conversion member which concerns on aspect 11 of this invention was equipped with the glass which has a softening point of 700 degreeC or more, and the 1 type or multiple types of fluorescent substance particle which emits fluorescence in response to excitation light. A method for manufacturing a wavelength conversion member, the step of coating at least one kind of phosphor particles among the phosphor particles with a coating layer containing αSiAlON, and dispersing the phosphor particles in the glass. And a process.

  According to said structure, compared with the conventional wavelength conversion member, there exists an effect that the wavelength conversion member which has higher wavelength conversion efficiency can be manufactured.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

  The present invention can also be expressed as follows.

  That is, the wavelength conversion member according to one embodiment of the present invention is a wavelength conversion member in which phosphor particles are dispersed in glass having a softening point of 700 ° C. or higher, and any one of the phosphor particles is Coated with αSiAlON.

  In the wavelength conversion member according to one embodiment of the present invention, the phosphor is an oxynitride phosphor or a nitride phosphor.

In the wavelength conversion member according to an aspect of the present invention, the phosphor coated with αSiAlON is at least one selected from βSiAlON or CaAlSiN ₃ .

  In the wavelength conversion member according to one embodiment of the present invention, the thickness of the coating layer made of αSiAlON is in the range of 10 nm to 10 μm.

  Moreover, the wavelength conversion member which concerns on 1 aspect of this invention WHEREIN: The peak wavelength of light emission of the said semiconductor light-emitting element is 300-500 nm.

  In the wavelength conversion member according to one embodiment of the present invention, the peak wavelength of light emission of the semiconductor light emitting element is 350 to 420 nm.

  In the wavelength conversion member according to one embodiment of the present invention, the glass having a softening point of 700 ° C. or higher is silica glass.

  Moreover, the wavelength conversion member which concerns on 1 aspect of this invention WHEREIN: The glass whose said softening point is 700 degreeC or more is oxynitride glass.

  The present invention can be used for a wavelength conversion member including a phosphor that converts excitation light into fluorescence, and a light emitting device including the wavelength conversion member.

DESCRIPTION OF SYMBOLS 1 Wavelength conversion member 10 Glass 11 Phosphor particle 23 Nitride laser (excitation light source)
26 Excitation light 27 Fluorescence 100 Light emitting device

Claims (11)

Glass having a softening point of 700 ° C. or higher;
One or more types of phosphor particles dispersed inside the glass and emitting fluorescence upon receiving excitation light,
The wavelength conversion member, wherein at least one of the phosphor particles is coated with a coating layer containing αSiAlON.   The wavelength conversion member according to claim 1, wherein the at least one kind of phosphor particles is an oxynitride phosphor or a nitride phosphor. The wavelength conversion member according to claim 2, wherein the at least one kind of phosphor particles is a βSiAlON phosphor or a CaAlSiN ₃ phosphor.   The thickness of the said coating layer is 10 nm or more and 100 micrometers or less, The wavelength conversion member of any one of Claim 1 to 3 characterized by the above-mentioned.   The wavelength conversion member according to claim 4, wherein the coating layer has a thickness of 100 nm or more and 100 μm or less.   6. The wavelength conversion member according to claim 1, wherein a peak wavelength of the excitation light is 300 nm or more and 500 nm or less.   The wavelength conversion member according to claim 6, wherein a peak wavelength of the excitation light is 350 nm or more and 420 nm or less.   The wavelength conversion member according to claim 1, wherein the glass is oxynitride glass.   The wavelength conversion member according to any one of claims 1 to 7, wherein the glass is silica glass. The wavelength conversion member according to any one of claims 1 to 9,
And an excitation light source that irradiates the wavelength conversion member with the excitation light. Glass having a softening point of 700 ° C. or higher;
1 or a plurality of types of phosphor particles that emit fluorescence in response to excitation light, and a method for producing a wavelength conversion member comprising:
Coating at least one of the phosphor particles with a coating layer containing αSiAlON;
And a step of dispersing the phosphor particles in the glass. A method for producing a wavelength conversion member, comprising:

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