JP2022030048A - Ceramic complex and method for producing the same - Google Patents

Abstract

To provide a method for producing a ceramic complex that emits light having high brightness with the reduced spread of emitted light.SOLUTION: A method for producing a ceramic complex includes the steps of: preparing a molding of the mixed raw material that contains a first rare earth aluminate phosphor with a first particle size of 0.1 μm or more and 2.0 μm or less by laser diffraction scattering and with a first standard deviation of 0.2 or more and 2.0 or less, a second rare earth aluminate phosphor with a second particle size of 2.1 μm or more and 20 μm or less and a second standard deviation of 0.2 or more and 0.7 or less, and rare earth oxide particles, where based on the total content of the first and second rare earth aluminate phosphors and the rare earth oxide particles of 100 mass%, the content of the first rare earth aluminate phosphor is 69 mass% or more and 95.8 mass% or less, the content of the second rare earth aluminate phosphor is 4 mass% or more and 30 mass% or less, and the content of the rare earth oxide particles is 0.2 mass% or more and 10 mass% or less; and subjecting the molding to a first heat treatment at 1200°C or higher and 1800°C or lower to obtain a first sintered body.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a ceramic complex and a method for producing the same.

A light emitting device including a light emitting diode (Light Emitting Diode: LED), a laser diode (Laser Diode: LD), and a wavelength conversion member including a phosphor is known. Such a light emitting device is used as a light source for, for example, a vehicle, a general lighting, a backlight of a liquid crystal display device, a projector, and the like.

As a wavelength conversion member provided in the light emitting device, for example, Patent Document 1 describes a cerium-aluminum-garnet-based phosphor activated by Ce and an inorganic material made of aluminum oxide existing between phosphor particles. The ceramic composite containing is disclosed.

Special Table 2010-514189

However, with respect to the ceramic complex used as a wavelength conversion member, it is required to further reduce the spread of the emitted light and emit light having high brightness.
It is an object of the present disclosure to provide a ceramic complex capable of emitting high-luminance light by reducing the spread of emitted light and a method for producing the same.

In the first aspect, the first particle size Dm ¹ , which has a cumulative frequency of 50% in the volume-based first particle size distribution by the laser diffraction scattering method, is within the range of 0.1 μm or more and 2.0 μm or less, and the first particle size is described. The first standard deviation Sd ¹ in the distribution is in the range of 0.2 or more and 2.0 or less, and the cumulative frequency is 50% in the volume-based second particle size distribution by the laser diffraction scattering method. The second particle size Dm ² is in the range of 2.1 μm or more and 20 μm or less, and the second standard deviation Sd ² in the second particle size distribution is in the range of 0.2 or more and 0.7 or less. The total amount of the first rare earth aluminate phosphor, the second rare earth aluminate phosphor, and the rare earth oxide particles is 100% by mass, including the acid acid phosphor and the rare earth oxide particles. The content of the first rare earth aluminate phosphor is in the range of 69% by mass or more and 95.8% by mass or less, and the content of the second rare earth aluminate phosphor is 4% by mass or more and 30% by mass. % Or less, and the content of the rare earth oxide particles is in the range of 0.2% by mass or more and 10% by mass or less. It is a method for producing a ceramic composite including preparing a body and heat-treating the molded body in a temperature range of 1200 ° C. or higher and 1800 ° C. or lower to obtain a first sintered body.

The second aspect is a ceramics composite containing a first rare earth aluminate phosphor crystal phase containing voids, a second rare earth aluminate phosphor crystal phase not containing voids, and a rare earth aluminate crystal phase. Is.

According to the present disclosure, it is possible to provide a ceramic complex capable of emitting high-luminance light by reducing the spread of emitted light and a method for producing the same.

FIG. 1 is a flowchart showing a method for manufacturing a ceramic complex. FIG. 2 is a flowchart showing a method for manufacturing a ceramic complex. FIG. 3 is a flowchart showing a method for manufacturing a ceramic complex. FIG. 4 is a graph showing the relationship between the particle size in the particle size distribution and the cumulative frequency (cumulative volume (%)) based on the volume of the particles. FIG. 5 is a graph showing the relationship between the particle size in the particle size distribution and the cumulative frequency (cumulative volume (%)) based on the volume of the particles. FIG. 6A is a schematic plan view of the light emitting device. FIG. 6B is a schematic cross-sectional view of the light emitting device. FIG. 7 is a schematic diagram showing a direction for measuring the light distribution chromaticity coordinates (x, y) of the emitted light of the ceramic complex. FIG. 8 is an SEM photograph of the surface of the ceramic complex according to Example 1. FIG. 9 is an SEM photograph of the surface of the ceramic complex according to Comparative Example 1.

Hereinafter, a method for producing a ceramic complex will be described based on an embodiment. However, the embodiments shown below are examples for embodying the technical idea of the present invention, and the present invention is not limited to the following method for manufacturing a ceramic complex. The relationship between the color name and the chromaticity coordinate, and the relationship between the wavelength range of light and the color name of monochromatic light follow JIS Z8110. Further, in the present specification, ceramics refers to any inorganic non-metal material at a temperature of 1000 ° C. or lower.

Manufacturing method of ceramic complex 1
The method for producing the ceramic composite is a first rare earth aluminate phosphor having a total content of 100% by mass and a content of 69% by mass or more and 95.8% by mass or less, and a content of 4% by mass. A raw material mixture containing a second rare earth aluminate phosphor having a content of 0.2% by mass or more and 10% by mass or less and rare earth oxide particles having a content of 0.2% by mass or more and 10% by mass or less was formed. This includes preparing a molded body and heat-treating the molded body in a temperature range of 1200 ° C. or higher and 1800 ° C. or lower to obtain a first sintered body. However, for convenience of explanation, the step of preparing the molded body may be divided into the preparation of the raw material mixture and the molding of the raw material mixture to prepare the molded body. Further, in the first rare earth aluminate phosphor, the first particle size Dm ¹ , which has a cumulative frequency of 50% in the volume-based first particle size distribution by the laser diffraction / scattering method, is within the range of 0.1 μm or more and 2.0 μm or less. Yes, the first standard deviation Sd ¹ in the first particle size distribution is within the range of 0.2 or more and 2.0 or less. Further, in the second rare earth aluminate phosphor, the second particle size Dm ² , which has a cumulative frequency of 50% in the volume-based second particle size distribution by the laser diffraction / scattering method, is within the range of 2.1 μm or more and 20 μm or less. The second standard deviation Sd ² in the second particle size distribution is within the range of 0.2 or more and 0.7 or less.

Since the first rare earth phosphor and the second rare earth phosphor have different particle size ranges and have the same or similar composition, at least two methods of crystal growth as described below are used. Is inferred.
(A) The particles of the first rare earth phosphor, which have a smaller particle size than the second rare earth phosphor, are gathered together, and the particles of the first rare earth phosphor are integrated into one rare earth phosphor. A phosphate phosphor crystal phase is formed.
(B) The first rare earth aluminate phosphor having a smaller particle size than the second rare earth aluminate phosphor gathers around the particles of the second rare earth aluminate phosphor, and becomes the first rare earth aluminate phosphor. The particles of the second rare earth aluminate phosphor are integrated to form one rare earth aluminate phosphor crystal phase.
The first rare earth phosphor and the second rare earth phosphor have different crystal growth rates due to the difference in particle size, and when the rare earth phosphor phosphor crystal phase is formed, the above-mentioned Voids are formed in any of the processes included in the method for producing the above-mentioned ceramic composite. The tendency for such voids to be formed is that the rate of crystal growth in which the particles of the first rare earth aluminate phosphor of the above (A) are integrated is higher than that of the above (B) due to the difference in particle size. Since the particles of the first rare earth aluminate phosphor and the particles of the second rare earth aluminate phosphor are faster than the integrated crystal growth rate, it is presumed that voids are formed due to the difference in the crystal growth rate. .. The crystal phase in which the particles of the first rare earth aluminate phosphor of the above (A) are integrated may contain voids, and the particles of the first rare earth aluminate phosphor and the second rare earth of the above (B) may be contained. The crystal phase in which the particles of the aluminate phosphor are integrated may also contain voids. The voids formed in the ceramic composite diffuse the incident light, and the wavelength is efficiently converted by the rare earth aluminate phosphor crystal phase, so that high-luminance light can be emitted from the ceramic composite. Further, by setting the content of the voids in a specific range and including the rare earth aluminate phosphor crystal phase containing the voids, the light emitted from the ceramic composite has less spread of the emitted light, and the target position. Is focused on. In the present specification, the rare earth aluminate phosphor crystal phase containing voids is also referred to as "first rare earth aluminate phosphor crystal phase containing voids". The rare earth aluminate phosphor crystal phase containing no voids is also referred to as "second rare earth aluminate phosphor crystal phase containing no voids".

The rare earth oxide particles react with aluminum contained in the first rare earth aluminate phosphor or the second rare earth aluminate phosphor to form a rare earth aluminate crystal phase in the ceramic composite body. Since the rare earth aluminate crystal phase is contained in the ceramic composite, the light incident on the ceramic composite hits the rare earth aluminate crystal phase, the light is refracted in the ceramic composite, and the lateral spread is suppressed. Therefore, when the light is emitted from the ceramic composite, the spread of the emitted light is reduced, and the light that can be focused at a target position can be emitted from the ceramic composite. Since the refractive index of the rare earth aluminate crystal phase formed in the ceramic composite is small in difference from the refractive index of the rare earth aluminate phosphor crystal phase, the light beam emitted from the ceramic composite is smaller than that of the voids. Can be suppressed.

1 to 3 are flowcharts showing an example of a method for manufacturing a ceramic complex. The process of the method for manufacturing the ceramic complex of the first embodiment will be described with reference to FIGS. 1 to 3. As shown in FIG. 1, the method for producing a ceramic composite is a molded product obtained by molding a raw material mixture containing a first rare earth aluminate phosphor, a second rare earth aluminate phosphor, and a rare earth oxide particle. Includes a step S101 for preparing the above and a step S102 for heat-treating the molded body to obtain a first sintered body. As shown in FIG. 2, in the method for producing a ceramic composite, after obtaining a first sintered body, a second heat treatment is performed by hot isostatic pressing (HIP) treatment to perform a second sintering. The step S103 for obtaining a body may be included. Further, the method for producing the ceramic complex may include a step S104 for annealing the first sintered body or the second sintered body. As shown in FIG. 3, the method for manufacturing a ceramic complex is a step S105 of cutting a first sintered body, a second sintered body, or an annealed second sintered body to a desired size or thickness and processing the composite. May be included, and further, a step S106 for surface treatment may be included.

Hereinafter, a method for manufacturing a ceramic complex will be described.

The particle size distribution of each particle of the first rare earth aluminate phosphor, the second rare earth aluminate phosphor, and the rare earth oxide particles measured by the laser diffraction scattering method is from the smaller particle size of the volume standard to the larger one. The particle size assumed for the equivalent sphere diameter is set on the horizontal axis (logarithmic axis), and the integrated value (cumulative volume (%)) is set on the vertical axis for plotting. The particle diameter assumed by the equivalent sphere diameter of the particles can be obtained from the angular distribution of the scattered light intensity of diffraction by the laser beam. FIG. 4 is a graph showing the relationship between the particle size in the particle size distribution and the cumulative frequency (cumulative volume (%)) based on the volume of the particles. The horizontal axis of the graph is the particle size (X), and the vertical axis is the cumulative volume (Q) (%). The particle size of the arbitrary integrated value (cumulative volume (%)) in the integrated value Q _a is defined as _Da , and the integrated value (cumulative volume (%)) Q _j in the two particle sizes X _j and X _{j + 1} on both sides of this _Da . And when Q _{j + 1} is known, the particle size _Da of the arbitrary integrated value in the integrated value Q _a can be calculated from the following equations (1) and (2). In the present specification, the median diameters having a cumulative frequency of 50% in the first particle size distribution, the second particle size distribution, and the third particle size distribution are defined as the first particle size Dm ¹ , the second particle size Dm ² , and the third particle size Dm ³ . ..

In the particle size distribution of each particle of the first rare earth aluminate phosphor, the second rare earth aluminate phosphor, and the rare earth oxide particles measured by the laser diffraction scattering method, the smaller particle size of the volume reference to the larger one. The particle size is integrated toward the particle size, the particle size is set on the horizontal axis, the integrated value (cumulative volume (%)) is set on the vertical axis, and plotting is performed as shown in FIG. FIG. 5 is a graph showing the relationship between the particle size in the particle size distribution and the cumulative frequency (cumulative volume (%)) based on the volume of the particles. The horizontal axis of the graph is the particle size (X or D), and the vertical axis is the cumulative volume (%). The cumulative volume (%) of the particle size Dm with a cumulative frequency of 50% to + 1σ is _84.135 , and the cumulative volume (%) of the particle size Dm with a cumulative frequency of 50% to -1σ is 15. The particle size D _15.865 of 865 can be measured, and the standard deviation (σlog) can be measured from the following formula (3). In the present specification, each standard deviation (σlog) in the first particle size distribution, the second particle size distribution, and the third particle size distribution is referred to as the first standard deviation Sd ¹ , the second standard deviation Sd ² , and the third standard deviation Sd ³ , respectively. And said.

First rare earth aluminate phosphor The first rare earth aluminate phosphor has a first particle size Dm ¹ of 0.1 μm or more, which has a cumulative frequency of 50% in the volume-based first particle size distribution by the laser diffraction scattering method. It is within the range of 0 μm or less, and the first standard deviation Sd ¹ in the first particle size distribution is within the range of 0.2 or more and 2.0 or less. The first particle size Dm ¹ of the first rare earth aluminate phosphor may be in the range of 0.2 μm or more and 1.8 μm or less, or may be in the range of 0.3 μm or more and 1.5 μm or less. The first standard deviation Sd ¹ in the first particle size distribution of the first rare earth phosphor is in the range of 0.2 or more and 2.0 or less, and the first rare earth phosphor has an appropriately dispersed particle size distribution. By using the body, a first sintered body containing a first rare earth aluminate phosphor crystal phase containing voids that does not reduce the density of the obtained first sintered body can be obtained. The first standard deviation Sd ¹ in the first particle size distribution of the first rare earth aluminate phosphor may be in the range of 0.3 or more and 1.8 or less, or may be in the range of 0.4 or more and 1.5 or less. It may be in the range of 0.5 or more and 1.2 or less.

The first rare earth aluminate phosphor is preferably obtained by the coprecipitation method. According to the coprecipitation method, the first particle size Dm ¹ has a relatively small particle size in the range of 0.1 μm or more and 2.0 μm or less, and the first standard deviation Sd ¹ in the first particle size distribution is 0. It is easy to obtain a first rare earth aluminate phosphor having a range of 2 or more and 2.0 or less.

As a method for forming the first rare earth aluminate phosphor by the co-precipitation method, for example, an oxide containing a constituent element contained in the composition of the first rare earth aluminate phosphor, or an oxide easily becomes an oxide at a high temperature. The compounds are prepared as raw materials, and each compound is weighed so as to have the composition of the first rare earth aluminate phosphor while considering the chemical quantitative ratio. Each compound weighed so as to have the composition of the first rare earth aluminate phosphor is dissolved in a liquid, and a precipitating agent is added to the solution and co-precipitated to obtain a co-precipitate. The oxide obtained by calcining the coprecipitate and other raw materials, for example, the oxide contained in the composition of the first rare earth aluminate phosphor, are weighed and the raw materials are wet or dry. Mix with. Flux may be added to the raw material. The first rare earth aluminate phosphor formed by the coprecipitation method can be obtained by calcining a mixture containing the oxide obtained by coprecipitation, other raw materials, and flux if necessary. .. Examples of the compound that easily becomes an oxide at high temperature include hydroxides, oxalates, carbonates, chlorides, nitrates, sulfates and the like containing elements constituting the composition of the first rare earth aluminate phosphor. Can be mentioned. Examples of the compound that easily becomes an oxide at a high temperature include a metal composed of elements constituting the composition of the first rare earth phosphor, for example, an oxide containing an aluminum metal. Examples of the liquid that dissolves the metal or each compound include deionized water. Examples of the precipitating agent include oxalic acid or oxalate, carbonates, ammonium hydrogencarbonate and the like. Examples of the oxalate include ammonium oxalate and the like, and examples of the carbonate include ammonium carbonate and the like.

Second rare earth aluminate phosphor The second rare earth aluminate phosphor has a second particle size Dm ² of 2.1 μm or more and 20 μm or less, which has a cumulative frequency of 50% in the volume-based second particle size distribution by the laser diffraction scattering method. The second standard deviation Sd ² in the second particle size distribution is within the range of 0.2 or more and 0.7 or less. The second particle size Dm ² of the second rare earth aluminate phosphor may be in the range of 2.5 μm or more and 18 μm or less, may be in the range of 3.0 μm or more and 15 μm or less, and may be in the range of 4.0 μm or more and 12 μm or less. But it may be. The second standard deviation Sd ² in the second particle size distribution of the second rare earth aluminate phosphor is preferably in the range of 0.2 or more and 0.7 or less, and it is preferable that the variation in particle size is small. The second standard deviation Sd ² in the second particle size distribution of the second rare earth aluminate phosphor may be in the range of 0.2 or more and 0.5 or less. A rare earth aluminate phosphor having a small first particle size Dm ¹ and / or a rare earth oxide particle gathering around a second rare earth phosphor having a large second particle size Dm ² . It is presumed that a salt phosphor crystal phase is formed. The smaller the variation in the particle size distribution of the second particle size Dm ² of the second rare earth aluminate phosphor, the larger the rare earth aluminate phosphor crystal phase formed in the ceramic composite in a substantially evenly dispersed state. It becomes easy to be done. When the relatively large rare earth aluminate phosphor crystal phase is dispersed substantially evenly in the ceramics composite, the incident light is diffused by the voids in the rare earth aluminate phosphor crystal phase containing voids, and the rare earth The wavelength is efficiently converted by the phosphoric acid phosphor crystal phase, the spread of the emitted light is reduced, and the light having high brightness can be emitted from the ceramic composite.

The production method of the second rare earth aluminate phosphor is not limited as long as the second particle size Dm ² in the second particle size distribution is within the above range and the second standard deviation Sd ² is within the above range. The second rare earth aluminate phosphor may be produced by the above-mentioned coprecipitation method, or may be produced by another method.

Composition of 1st Rare Earth Aluminate Fluorite and 2nd Rare Earth Aluminate Fluorescent The 1st rare earth aluminate phosphor and the 2nd rare earth aluminate phosphor are a group consisting of Y, La, Lu, Gd and Tb. It contains at least one rare earth element Ln ¹ , Ce, and Al selected from, and if necessary, at least a part of Al is replaced with at least one element M ¹ selected from Ga and Sc. The total molar ratio of the rare earth elements Ln ¹ and Ce is 3, and the total molar ratio of Al and the element M ¹ is the product of variables k and 5 of 0.95 or more and 1.05 or less. It is preferable to have a first composition in which the molar ratio of the above is 0.003 or more and 0.030 or less, which is the product of the variable n and 3. The first rare earth aluminate phosphor and the second rare earth aluminate phosphor are both rare earth aluminate phosphors having a composition of a rare earth aluminate containing at least Ce as an activating element, so that the brightness is high. The first sintered body can be obtained.

It is preferable that the first rare earth phosphor and the second rare earth phosphor have the first composition represented by the following formula (I).
(Ln ¹ _{1-n Cen} ) ₃ (Al _1-m M ¹ _m ) _5k O ₁₂ (I)
(In formula (I), Ln ¹ is at least one rare earth element selected from the group consisting of Y, La, Lu, Gd and Tb, and M ¹ is at least one selected from Ga and Sc. M, n, and k are numbers that satisfy 0 ≦ m ≦ 0.1, 0.003 ≦ n ≦ 0.030, and 0.95 ≦ k ≦ 1.05, respectively.)

The first rare earth phosphor and the second rare earth phosphor may have the same composition or may have different compositions.

Rare earth oxide particles In rare earth oxide particles, the third particle size Dm ³ , which has a cumulative frequency of 50% in the volume-based third particle size distribution by the laser diffraction scattering method, is within the range of 0.5 μm or more and 5 μm or less, and the particle size distribution. It is preferable that the third standard deviation Sd ³ in the above is in the range of 0.2 or more and 1.0 or less. If the third particle size Dm ³ of the rare earth oxide particles is within the range of 0.5 μm or more and 5 μm or less, and the third standard deviation Sd ³ is within the range of 0.2 or more and 1.0 or less, the heat treatment described later is performed. In the process, the rare earth phosphor integrated with the first rare earth phosphor or the second rare earth phosphor, or different from the first rare earth phosphor and the second rare earth phosphor. Form an acid acid crystal phase. The ceramics composite contains a rare earth aluminate crystal phase having a composition different from that of the first rare earth aluminate phosphor crystal phase containing voids and the second rare earth aluminate phosphor not containing voids. The scattering of light is controlled in the complex, the spread of the emitted light is reduced, and the light that can be focused at the target position can be emitted from the ceramic composite. Since the difference between the refractive index of the rare earth aluminate crystal phase in the ceramic composite and the refractive index of the rare earth aluminate phosphor crystal phase is small, the light beam emitted from the ceramic composite is lower than that of the void. Can be suppressed. The third particle size Dm ³ of the rare earth oxide particles may be in the range of 1.0 μm or more and 4.0 μm or less, or may be in the range of 1.2 μm or more and 3.5 μm or less. It is preferable that the third standard deviation Sd ³ in the third particle size distribution of the rare earth oxide particles is in the range of 0.2 or more and 1.0 or less, and the variation in particle size is small. The third standard deviation Sd ³ in the third particle size distribution of the rare earth oxide particles may be in the range of 0.3 or more and 0.8 or less.

The rare earth oxide particles preferably contain at least one rare earth element Ln ² selected from the group consisting of Y, La, Lu, Gd, Tb and Ce. Specific examples of the rare earth _oxide include _Y2O3 , _{La2O3 , Lu2O3 , Gd2O3 , Tb2O3 ,} and _CeO2 . The rare earth oxide particles react with the first rare earth aluminate phosphor or the second rare earth aluminate phosphor to form a first rare earth aluminate phosphor crystal phase and a second rare earth aluminate phosphor crystal phase. Form a rare earth aluminate crystal phase with different crystal structures.

Step of preparing a raw material mixture In a method for producing a ceramic composite, a raw material mixture containing a first rare earth aluminate phosphor, a second rare earth aluminate phosphor, and a rare earth oxide particle is prepared. The raw material mixture has a content of the first rare earth aluminate phosphor of 69% by mass, where the total amount of the first rare earth aluminate phosphor, the second rare earth aluminate phosphor and the rare earth oxide particles is 100% by mass. It is in the range of 95.8% by mass or less, the content of the second rare earth aluminate phosphor is in the range of 4% by mass or more and 30% by mass or less, and the content of the rare earth oxide particles is 0.2. It is in the range of 10% by mass or less by mass. The raw material mixture has a content of the first rare earth aluminate phosphor of 70% by mass, where the total amount of the first rare earth aluminate phosphor, the second rare earth aluminate phosphor and the rare earth oxide particles is 100% by mass. The content of the second rare earth aluminate phosphor may be in the range of 8% by mass or more and 28% by mass or less, and the rare earth oxide particles may be in the range of 91.7% by mass or less. It may be in the range of 0.3% by mass or more and 8% by mass or less. The raw material mixture has a content of the first rare earth aluminate phosphor of 72% by mass, where the total amount of the first rare earth aluminate phosphor, the second rare earth aluminate phosphor and the rare earth oxide particles is 100% by mass. The content of the second rare earth aluminate phosphor may be in the range of 9% by mass or more and 25% by mass or less, and the rare earth oxide particles may be in the range of 90.6% by mass or more. It may be in the range of 0.4% by mass or more and 7% by mass or less. When the content of each component in the raw material mixture is within the above range, the first rare earth aluminate phosphor crystal phase containing voids and voids due to the difference in the rate of crystal growth due to the difference in particle size or crystal structure. It is possible to obtain a ceramic composite containing a large and small second rare earth aluminate phosphor crystal phase containing no voids and a rare earth aluminate crystal phase containing no voids.

The raw material mixture may be mixed using a mortar and a pestle, or may be mixed using a mixing medium such as a ball mill. Further, in order to facilitate uniform mixing of the powder, a mixing medium such as water or ethanol may be used. Further, a dispersant may be used to enhance the dispersibility of the powder. The mixing medium is preferably one that easily volatilizes in order to form a raw material mixture of powder at the time of molding. The mixing medium is preferably in the range of 10 parts by mass or more and 200 parts by mass or less, and may be in the range of 50 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the raw material mixture. As the dispersant, for example, an aqueous dispersant can be used, and a cationic dispersant, an anionic dispersant, a nonionic dispersant, or the like can be used. When the dispersant is added to the raw material mixture, the amount is preferably an amount that can be volatilized in the subsequent heat treatment step with respect to 100% by mass of the raw material mixture, and may be 5% by mass or less, and may be 3% by mass or less. It may be 1% by mass or less.

Step of preparing a molded product The raw material mixture can be molded by adopting a known method such as a press molding method. Examples of the press forming method include a die press forming method, a forming method of compressing in a uniaxial direction by a roller bench method, JIS Z2500: 2000, No. Examples include the Cold Isostatic Pressing (CIP) method, the term of which is defined in 2109. As the molding method, two types of methods may be adopted in order to adjust the shape of the molded body. For example, CIP may be performed after mold press molding, and the roller bench method is used to pressurize in the uniaxial direction. CIP may be performed after compression molding. The CIP preferably uses a liquid such as water as a medium. It is preferable that the raw material mixture forms a molded product by CIP. By placing the raw material mixture in a packaging container and pressurizing it isotropically with CIP, a first rare earth aluminate phosphor having a small first particle size Dm ¹ and a second rare earth element having a large second particle size Dm ² are used. Since the adhesion of the alumate phosphor is enhanced, the crystal can be grown by the heat treatment described later while forming voids to the extent that the incident light can be scattered without lowering the density.

The pressure at the time of mold press molding or the pressure at the time of uniaxial compression molding is preferably 5 MPa or more and 50 MPa or less, and more preferably 5 MPa or more and 30 MPa or less. If the pressure at the time of die press molding or the pressure at the time of uniaxial compression molding is within the above range, the molded product can be adjusted to a desired shape.

The pressure in the CIP is preferably 50 MPa or more and 200 MPa or less, and more preferably 50 MPa or more and 180 MPa or less. When the pressure in the CIP is in the range of 50 MPa or more and 200 MPa or less, the raw material mixture is isotropically pressed to increase the density of the molded product, and the relative density is 90% or more and the porosity is 1% by the first heat treatment. It is possible to form a molded body capable of obtaining a first sintered body within the range of 10% or less.

Step of obtaining the first sintered body by the first heat treatment The temperature of the first heat treatment is preferably in the temperature range of 1200 ° C. or higher and 1800 ° C. or lower, and more preferably in the temperature range of 1400 ° C. or higher and 1790 ° C. or lower. It is preferable that the temperature is in the temperature range of 1600 ° C. or higher and 1780 ° C. or lower. When the temperature at which the molded body is first heat-treated is 1200 ° C. or higher, the rate of crystal growth can be different due to the difference in the particle size or crystal structure of each component, and the first rare earth aluminate phosphor crystal phase containing voids. , A first sintered body containing a second rare earth aluminate phosphor crystal phase and a rare earth aluminate crystal phase containing no voids can be obtained. When the temperature at which the molded product is first heat-treated is 1800 ° C. or lower, the first rare earth aluminate phosphor crystal phase containing voids and voids are not contained without melting so that the grain boundaries of each crystal phase disappear. A first sintered body containing a second rare earth aluminate phosphor crystal phase and a rare earth aluminate crystal phase can be obtained. The atmosphere of the first heat treatment may be an atmospheric atmosphere, an oxygen-containing atmosphere, an inert atmosphere, or a reducing atmosphere.

Step of obtaining a second sintered body by the second heat treatment The obtained first sintered body may be subjected to the second heat treatment to obtain a second sintered body. The second heat treatment was performed by JIS Z2500: 2000, No. It is preferable to heat-treat in a temperature range of 1500 ° C. or higher and 1800 ° C. or lower by hot isotropic pressure pressurization (HIP) treatment as defined in 2112 to obtain a second sintered body. By performing the second heat treatment while isotropically pressurizing with HIP, the surface of the first sintered body is not crushed by the voids (closed pores) incorporated in the crystal phase of the first rare earth aluminate phosphor. The voids (open pores) formed in the above can be crushed to increase the density of the obtained second sintered body. The temperature of the second heat treatment is more preferably in the temperature range of 1550 ° C. or higher and 1790 ° C. or lower, and further preferably in the temperature range of 1600 ° C. or higher and 1780 ° C. or lower.

The second heat treatment is preferably performed in an inert gas atmosphere. The inert gas atmosphere means an atmosphere containing argon, helium, nitrogen or the like as the main components of the atmosphere. Here, the term "argon, helium, nitrogen or the like as the main component in the atmosphere" means that the atmosphere contains at least 50% by volume or more of at least one gas selected from the group consisting of argon, helium, nitrogen and the like. When the atmosphere of the secondary firing is an inert gas atmosphere, deterioration of the crystal structure of each crystal phase is suppressed by the second heat treatment, and a second sintered body having a high relative density can be obtained.

The pressure in the HIP treatment is preferably in the range of 50 MPa or more and 300 MPa or less, and more preferably in the range of 80 MPa or more and 200 MPa or less. When the pressure in the HIP treatment is in the range of 50 MPa or more and 300 MPa or less, a second sintered body having a higher density can be obtained without deteriorating the crystal structure of each crystal phase.

The time of the HIP treatment is, for example, 0.5 hours or more and 20 hours or less, and preferably 1 hour or more and 10 hours or less.

Step of Annealing The obtained second sintered body is preferably annealed in an oxygen-containing atmosphere. By annealing the obtained second sintered body in an oxygen-containing atmosphere, the first rare earth phosphorate fluorescence contained in the first sintered body or the second sintered body by the first heat treatment or the second heat treatment. The dullness of the body color of the body crystal phase and the second rare earth aluminate phosphor crystal phase can be restored to the original body color, and the decrease in wavelength conversion efficiency caused by the dullness of the body color can be suppressed. .. The oxygen-containing atmosphere is preferably the same as the oxygen-containing atmosphere at the time of the first heat treatment. The oxygen content in the atmosphere in the annealing step is preferably 5% by volume or more, more preferably 10% by volume or more, still more preferably 15% by volume or more, and the atmosphere (oxygen content is 20% by volume or more) atmosphere. It may be. The amount of oxygen in the atmosphere may be measured by, for example, the amount of oxygen flowing into the firing apparatus, or may be measured at a temperature of 20 ° C. and a pressure of atmospheric pressure (101.325 kPa). The atmospheric pressure for annealing may be atmospheric pressure (101.325 kPa).

The annealing temperature is lower than that of the first heat treatment or the second heat treatment, and is preferably in the range of 1000 ° C. or higher and 1600 ° C. or lower. The annealing temperature is more preferably in the range of 1000 ° C. or higher and 1600 ° C. or lower, and further preferably in the range of 1100 ° C. or higher and 1400 ° C. or lower. If the annealing temperature is lower than the temperature of the first heat treatment or the second heat treatment and is within the range of 1000 ° C. or higher and 1600 ° C. or lower, the body color is dull without reducing the voids in the sintered body. It is possible to obtain a ceramic composite capable of emitting high-brightness light by eliminating the above.

Processing Step The obtained first sintered body or second sintered body may be processed to be cut to a desired size or thickness. As a cutting method, a known method can be used, and examples thereof include a method of cutting using blade dicing, laser dicing, and a wire saw. Of these, a wire saw is preferable from the viewpoint of suppressing the formation of irregularities on the cut surface.

Surface treatment step Further, the surface treatment step described below may be added. The surface treatment step is a step of surface-treating the surface of the cut product obtained by cutting the obtained first sintered body or the second sintered body. By this surface treatment step, in order to improve the light emitting characteristics of the first sintered body or the second sintered body, not only the surface of the first sintered body or the second sintered body can be brought into an appropriate state, but also the surface of the first sintered body or the second sintered body can be brought into an appropriate state. In combination with or alone in the above-mentioned processing steps, it is possible to obtain a ceramic composite in which the first sintered body or the second sintered body has a desired shape, size or thickness. The surface treatment step may be performed before the processing step of cutting the first sintered body or the second sintered body to a desired size or thickness and processing, or may be performed after the processing step. Examples of the surface treatment method include a method by sandblasting, a method by mechanical grinding, a method by dicing, a method by chemical etching, and the like.

Ceramic composite The ceramic composite contains a first rare earth aluminate phosphor crystal phase containing voids, a second rare earth aluminate phosphor crystal phase containing no voids, and a rare earth aluminate crystal phase.

In the ceramics composite, the first rare earth aluminate phosphor crystal phase containing voids (hereinafter, also referred to as "first rare earth aluminate phosphor crystal phase C1") and the second rare earth aluminate not containing voids. The salt phosphor crystal phase (hereinafter, also referred to as “second rare earth aluminate crystal phase C2”) has almost the same composition as the first rare earth aluminate phosphor or the second rare earth aluminate phosphor. Contains at least one rare earth element Ln ¹ , Ce, and Al selected from the group consisting of Y, La, Lu, Gd, and Tb, and if necessary, at least a part of the Al. It may be substituted with at least one element M ¹ selected from Ga and Sc, the total molar ratio of the rare earth element Ln ¹ and Ce is 3, and the total molar ratio of Al and the element M ¹ is. It is preferable to have a first composition which is a product of variables k and 5 having a molar ratio of 0.95 or more and 1.05 or less and a product of variables n and 3 having a molar ratio of Ce of 0.003 or more and 0.030 or less. In the ceramic composite, the first rare earth aluminate phosphor crystal phase C1 and the second rare earth aluminate phosphor crystal phase C2 preferably have the first composition represented by the above formula (I).

The ceramics composite is a rare earth aluminate crystal phase formed by reacting rare earth oxide particles with aluminum contained in a first rare earth aluminate phosphor or a second rare earth aluminate phosphor (hereinafter, "" Also referred to as "rare earth aluminate crystal phase C3"). The rare earth aluminate crystal phase C3 has a crystal structure different from that of the first rare earth aluminate phosphor crystal phase C1 and the second rare earth aluminate phosphor crystal phase C2. Further, since the rare earth aluminate crystal phase C3 has a different crystal structure from the first rare earth aluminate phosphor or the second rare earth aluminate phosphor, for example, the rare earth oxide particles become an activating element like CeO ₂ . Even if it contains the element to be obtained, it absorbs the light that becomes the excitation light and does not emit light. For example, when the first rare earth aluminate phosphor crystal phase C1 and the second rare earth aluminate phosphor crystal phase C2 have a cubic garnet structure containing Ce as an activating element, the rare earth oxide particles and the rare earth alumin The acid acid crystal phase C3 may have a rectangular perovskite structure such as YAP (yttrium aluminum perovskite, YAlO ₃ ). The rare earth aluminate crystal phase C3 may have a monoclinic structure such as YAM (yttrium aluminum monoclinic, _{Y4 Al 2 O 9 ) .} The third rare earth aluminate crystal phase C3 preferably has an orthorhombic perovskite structure. When the rare earth aluminate crystal phase C3 has a cubic perovskite structure, the first rare earth aluminate phosphor crystal phase C1 containing voids or the second rare earth aluminate fluorescence containing no voids. Since the crystal structure is different from the cubic garnet structure of the body crystal phase C2, the scattering of light wavelength-converted by the first rare earth aluminate phosphor crystal phase C1 and the second rare earth aluminate phosphor crystal phase C2. Can be suppressed, the spread can be reduced, and light that can be focused at a target position can be emitted from the ceramic composite.

In the ceramic composite, the rare earth aluminate crystal phase contains a rare earth element contained in the above-mentioned rare earth oxide particles. The rare earth element contained in the rare earth aluminate crystal phase is preferably at least one rare earth element Ln ² selected from the group consisting of Y, La, Lu, Gd, Tb and Ce. The rare earth aluminate crystal phase contains at least one rare earth element Ln ² selected from the group consisting of Y, La, Lu, Gd, Tb and Ce, and Al, and if necessary, at least one of Al. The part may be replaced with at least one element M ² selected from the group consisting of Ga and Sc, the molar ratio of the rare earth element Ln ² is 1, and the total molar of Al or Al and the element M ² is 1. It is preferable to have a second composition having a ratio of 1.

The rare earth aluminate crystal phase preferably has a second composition represented by the following formula (II).
Ln ² Al _1-p M ² _p O ₃ (II)
(In formula (II), Ln ² is at least one rare earth element selected from the group consisting of Y, La, Lu, Gd, Tb and Ce, and M ² is selected from the group consisting of Ga and Sc. It is at least one element to be formed, and p is a number satisfying 0 ≦ p ≦ 0.8.)

In the ceramics composite, the crystal phase formed by integrating the particles of the first rare earth aluminate phosphor having a relatively small first particle size Dm ¹ and growing crystals is more likely to contain voids, and the voids are more likely to be contained. The first rare earth aluminate phosphor crystal phase containing the above is likely to be formed. This is because the particles of the first rare earth aluminate phosphor having a relatively small first particle size Dm ¹ have a higher crystal growth rate, the first rare earth aluminate phosphor and the particles, and the second rare earth aluminate fluorescence. It is thought that this is because the particles of the body are integrated and the crystal grows at a high speed. As described above, the particles of the first rare earth aluminate phosphor having a relatively small first particle size Dm ¹ and the particles of the second rare earth aluminate phosphor having a relatively large second particle size Dm ² . The crystal phase in which the above is integrated may also contain voids, and a first rare earth aluminate phosphor crystal phase having voids may be formed. The crystal phase of the first rare earth aluminate phosphor having voids was formed by integrally growing crystals of the particles of the first rare earth aluminate phosphor having a relatively small first particle size Dm ¹ . The particles of the first rare earth aluminate phosphor having a relatively small first particle size Dm ¹ and the particles of the second rare earth aluminate phosphor having a relatively large second particle size Dm ² are integrated. It is not possible to determine whether the particles are formed by crystal growth.

In the ceramic composite, the first rare earth aluminate phosphor crystal phase C1 containing voids and the second rare earth aluminate phosphor crystal phase C2 not containing voids have a crystal diameter equivalent to a circle of 0.2 μm or more and 30 μm or less. It may be within the range of 1 μm or more and 25 μm or less. The crystal diameter corresponding to the circle of the first rare earth aluminate phosphor crystal phase C1 containing voids tends to be larger than the crystal diameter corresponding to the circle of the second rare earth aluminate phosphor crystal phase C2 containing voids. be.

In the ceramic composite, the rare earth aluminate crystal phase C3 produced by reacting the rare earth oxide particles with the aluminum contained in the first rare earth aluminate phosphor or the second rare earth aluminate phosphor has voids. Does not contain. The rare earth aluminate crystal phase C3 does not contain voids because the grain size of the rare earth oxide particles is relatively small and the reactivity is good, and the rare earth oxide particles are the first rare earth aluminate phosphor or the second rare earth aluminic acid. Since it easily reacts with a part of the components of the salt phosphor (for example, Al or element M ¹ ), it is considered that voids are unlikely to be formed in the rare earth aluminate crystal phase C3. The crystal grain size of the rare earth aluminate crystal phase C3 may be 0.5 μm or more, 1.0 μm or more, 10 μm or less, or 8 μm or less.

The crystal grain size corresponding to the circle of each crystal phase contained in the ceramic complex can be measured as follows. Using a scanning electron microscope (SEM), observe the SEM image of the surface or cross section of the ceramic composite, and in the SEM image, the maximum diameter in one crystal phase separated by each crystal phase boundary. The value and the minimum value are measured, or the diameters of two or more points of one crystal phase are measured, and the average value of the maximum value and the minimum value, or the average value of the diameters of two or more points is set as the circle of the crystal phase. It can have a considerable crystal grain size. For example, the crystal grain size corresponding to a circle of a plurality of, for example, 20 crystal phases in the SEM image of the surface or the cross section of the rare earth aluminate sintered body is measured, and the total value of the crystal grain size corresponding to the circle of each crystal phase is calculated. The arithmetic average value divided by the number of crystal phases to be measured can be used as the average crystal grain size corresponding to the circle of each crystal phase.

The relative density of the ceramic complex is preferably in the range of 97% or more and 99.98% or less, more preferably 97.5% or more, still more preferably 98% or more, and more preferably 99.95. % Or less, more preferably 99.90% or less. When the relative density of the ceramic composite is in the range of 97% or more and 99.98% or less, the excitation light incident on the ceramic composite is diffused in the voids, and the first rare earth aluminate phosphor crystal phase and the second are. The wavelength is efficiently converted by the rare earth aluminate phosphor crystal phase, and high-intensity light can be emitted from the ceramic composite. Further, since the ceramic composite contains a rare earth aluminate crystal phase, the spread of light in the ceramic composite is reduced, and light that can be focused at a target position can be emitted.

The void ratio of the ceramic composite is preferably in the range of 0.01% or more and 1% or less, more preferably in the range of 0.05% or more and 0.80% or less, and further preferably 0.10%. It is in the range of 0.50% or less, more preferably 0.12% or more and 0.40% or less, and particularly preferably 0.15% or more and 0.30% or less. .. The content of voids in the crystal phase of the first rare earth aluminate phosphor of the ceramic composite is defined as the porosity of the ceramic composite. When the void ratio of the ceramic composite is within the above range, the incident light is diffused in the void in the ceramic composite, and the efficiency is achieved in the first rare earth aluminate phosphor crystal phase and the second rare earth aluminate phosphor crystal phase. Light with high brightness can be emitted from the ceramic composite by being wavelength-converted. In addition, the spread of the emitted light is reduced, and light that can be focused at a target position is emitted from the ceramic complex.

The porosity of the ceramic composite is measured from an SEM image of the surface or cross section of the ceramic composite obtained using SEM. The porosity of the ceramic composite refers to the ratio (%) of the total area of the void (nm ² ) to the area of the measurement target of the SEM image of the surface or the cross section of the ceramic composite. Specifically, the void ratio of the ceramic composite is determined by performing image analysis on the SEM image of the surface or cross section of the ceramic composite obtained by using SEM using image analysis software (for example, ImageJ) in the SEM image. The outer shape of the voids can be confirmed in the phosphor crystal phase of the above. Perform binarization treatment. For the binarized measurement target, the total area (nm ² ) of the voids in the first rare earth aluminate phosphor crystal phase obtained by the binarization treatment with respect to the total area (nm ² ) at the resolution of the SEM image is calculated. Expressed as a ratio (%). Image analysis software "ImageJ" is an open source and public domain image analysis processing software developed by the National Institutes of Health.

The ceramic complex is a transmission type wavelength conversion in which the incident surface (first main surface) on which the excitation light is incident and the exit surface (second main surface) on which the wavelength-changed light is emitted face each other. It can be used as a member. When the ceramic composite is used as a transmission type wavelength conversion member in which the entrance surface of the excitation light and the emission surface of the light face each other, the thickness of the ceramic composite is not limited, and the ceramic composite is a plate. In the case of a state, the plate thickness is preferably in the range of 90 μm or more and 250 μm or less, and more preferably in the range of 100 μm or more and 240 μm or less.

The obtained ceramic complex can be used in a light emitting device by combining it with a light source as a wavelength conversion member.

Light emitting device The light emitting device includes the above-mentioned ceramic complex and an excitation light source. The ceramic complex described above may be used as it is as a wavelength conversion member, or may be included in the wavelength conversion member together with other members.

FIG. 6A shows an example of the light emitting device and is a schematic plan view of the light emitting device 100, and FIG. 6B is a schematic cross-sectional view of the VIB-VIB'line of the light emitting device 100 shown in FIG. 6A. The light emitting device 100 includes a light emitting element 20 and a wavelength conversion member 30 made of a ceramic composite that is excited by light from the light emitting element 20 to emit light. The light emitting element 20 is flip-chip mounted on the substrate 10 via a bump which is a conductive member 60. The wavelength conversion member 30 is provided on the light emitting surface of the light emitting element 2 via the adhesive layer 40. The side surface of the light emitting element 20 and the wavelength conversion member 30 is covered with a covering member 50 that reflects light. The light emitting element 20 can emit light from the light emitting device 100 by receiving electric power from the outside of the light emitting device 100 via the wiring and the conductive member 60 formed on the substrate 10. The light emitting device 100 may include a semiconductor element 70 in addition to the light emitting element 20. The covering member 50 is provided so as to cover, for example, the semiconductor element 70. The coating member 50 may include the resin 51 and at least one additive 52 selected from the group consisting of colorants, phosphors and fillers. Hereinafter, each member used in the light emitting device will be described. For details, for example, the disclosure of JP-A-2014-112635 can also be referred to.

Excitation light source The excitation light source is preferably a semiconductor light emitting device composed of an LED chip or an LD chip. As the semiconductor light emitting device, a nitride-based semiconductor can be used. By using a semiconductor light emitting device as an excitation light source, it is possible to obtain a stable light emitting device having high efficiency, high output linearity with respect to input, and resistance to mechanical impact. The ceramic composite can form a light emitting device that converts the wavelength of the light emitted from the nitride semiconductor light emitting device and emits the wavelength-converted mixed color light. The nitride-based semiconductor light emitting device preferably emits light in a wavelength range of, for example, 350 nm or more and 500 nm or less. It is preferable that the ceramic composite emits emitted light having an emission peak wavelength in the range of 500 nm or more and less than 650 nm by wavelength-converting the excitation light from the nitride semiconductor light emitting device.

The semiconductor light emitting device preferably has an emission peak wavelength in the range of 380 nm or more and 500 nm or less, more preferably has an emission peak wavelength in the range of 390 nm or more and 495 nm or less, and further preferably has an emission peak wavelength in the range of 400 nm or more and 490 nm or less. Has an emission peak wavelength, and particularly preferably has an emission peak wavelength in the range of 420 nm or more and 490 nm or less. The semiconductor light emitting device is provided with a p electrode and an n electrode. The p electrode and the n electrode of the semiconductor light emitting device may be formed on the same side surface of the semiconductor light emitting device, or may be provided on different side surfaces. The semiconductor light emitting device may be mounted on a flip chip.

Wavelength conversion member As the wavelength conversion member, the above-mentioned ceramic composite can be used. The thickness of the ceramic complex used as the wavelength conversion member may be in the range of 50 μm or more and 500 μm or less, in the range of 60 μm or more and 450 μm or less, or in the range of 70 μm or more and 400 μm or less. good. The size of the ceramic complex used as the wavelength conversion member may be a size that covers the entire light extraction surface of the light emitting element. An adhesive layer may be interposed between the light emitting element and the wavelength conversion member, or the light emitting element and the wavelength conversion member may be fixed by the adhesive layer. The adhesive constituting the adhesive layer is preferably made of a material capable of optically connecting the light emitting element and the wavelength conversion member. The material constituting the adhesive layer is preferably at least one resin selected from the group consisting of epoxy resin, silicone resin, phenol resin, and polyimide resin.

Substrate The substrate is preferably made of an insulating material that does not easily transmit light from a light emitting element or external light. Examples of the material of the substrate include ceramics such as aluminum oxide and aluminum nitride, phenol resin, epoxy resin, polyimide resin, bismaleimide triazine resin (BT resin), and polyphthalamide (PPA) resin. Ceramics have high heat resistance and are therefore preferable as a substrate material.

Adhesive layer An adhesive layer is interposed between the light emitting element and the wavelength conversion member to fix the light emitting element and the wavelength conversion member. The adhesive constituting the adhesive layer is preferably made of a material capable of optically connecting the light emitting element and the wavelength conversion member. The material constituting the adhesive layer is preferably at least one resin selected from the group consisting of epoxy resin, silicone resin, phenol resin, and polyimide resin.

Semiconductor elements Examples of the semiconductor elements provided in the light emitting device include a transistor for controlling the light emitting element and a protective element for suppressing the destruction and performance deterioration of the light emitting element due to the application of an excessive voltage. Examples of the protective element include a Zener diode and a capacitor.

Covering member As the material of the covering member, it is preferable to use an insulating material. More specifically, phenol resin, epoxy resin, bismaleimide triazine resin (BT resin), polyphthalamide (PPA) resin, silicone resin and the like can be mentioned. The covering member may contain at least one additive selected from the group consisting of colorants, phosphors and fillers, if necessary.

Conductive member A bump can be used as the conductive member, Au or an alloy thereof is used as the material of the bump, and eutectic solder (Au-Sn), Pb-Sn, lead-free solder or the like is used as another conductive member. be able to.

Method for manufacturing a light emitting device An example of a method for manufacturing a light emitting device will be described. For details, for example, the disclosure of JP-A-2014-112635 or JP-A-2017-117912 can also be referred to. The manufacturing method of the light emitting device includes a step of arranging a light emitting element, a step of arranging a semiconductor element if necessary, a step of forming a wavelength conversion member including a ceramic composite, a step of adhering the light emitting element and the wavelength conversion member, and a step of forming a covering member. It is preferable to include.

Arrangement process of light emitting element In the process of arranging the light emitting element, the light emitting element is arranged and mounted on the substrate. The light emitting element and the semiconductor element are, for example, flip-chip mounted on a substrate.

Adhesion step between the light emitting element and the wavelength conversion member In the bonding step between the light emitting element and the wavelength conversion member, the wavelength conversion member is opposed to the light emitting surface of the light emitting element, and the wavelength conversion member is bonded onto the light emitting element by an adhesive layer.

Coating member forming step In the covering member forming step, the side surfaces of the light emitting element and the wavelength conversion member excluding the light emitting surface are covered with the coating member composition, and the side surfaces of the light emitting element and the wavelength conversion member excluding the light emitting surface are covered. A covering member is formed. This covering member is for reflecting the light emitted from the light emitting element, and is formed so as to cover the side surface of the wavelength conversion member without covering the light emitting surface and to embed the semiconductor element.

As described above, the light emitting device shown in FIGS. 6A and 6B can be manufactured.

Hereinafter, the present invention will be specifically described with reference to Examples. The present invention is not limited to these examples.

First rare earth aluminate phosphor Yttrium chloride (YCl _{3), cerium chloride (CeCl 3 )} , aluminum chloride (AlCl ₃ ), gadolinium chloride (GdCl ₃ ), (Y _2.44 Gd _0.55 Ce _0.003 ) ) ₃ Weighed so as to have a composition represented by Al ₅ , and dissolved in deionized water to prepare a mixed solution. This mixed solution was poured into a (NH ₃ ) ₂ CO ₃ solution, and a carbonate represented by (Y _2.44 Gd _0.55 Ce _0.003 ) ₃ Al _{5 ·} xCO ₃ was obtained by the coprecipitation method. .. X in the composition is a value obtained by dividing the absolute value of the charge of the (Y _2.44 Gd _0.55 ^Ce _0.003 ) ₃ Al ₅ ion by the absolute value of the charge of the carbonate ion (CO _3-2- ). This carbonate was placed in an alumina crucible and baked in an atmospheric atmosphere (101.3 kPa) in the range of 1200 ° C to 1600 ° C for 10 hours to obtain a calcined product. The obtained calcined product was classified by passing through a dry sieve, and was produced by a coprecipitation method having a composition represented by (Y _2.44 Gd _0.55 Ce _0.003 ) ₃ Al ₅ O ₁₂ . A rare earth phosphor (coprecipitated YAG phosphor) was prepared. The first particle size Dm ¹ of the first rare earth aluminate phosphor measured by the measuring method described later was 0.201 μm, and the first standard deviation Sd ¹ was 1.08.

Second rare earth aluminate phosphor Yttrium oxide (Y ₂ O ₃ ), cerium oxide (CeO ₂ ), aluminum oxide (Al ₂ O ₃ ), gadolinium oxide (Gd ₂ O ₃ ), (Y _2.40 Gd) _0.60 Ce _0.003 ) ₃ Al ₅ O ₁₂ was weighed and mixed, aluminum fluoride (AlF ₃ ) was added as a flux, and the mixture was mixed with a ball mill. This mixture was placed in an alumina crucible and calcined in a reducing atmosphere in the range of 1400 ° C to 1600 ° C for 10 hours to obtain a calcined product. The obtained calcined product is dispersed in deionized water, and a solvent stream is passed through a sieve while applying various vibrations to pass through a wet sieve, then dehydrated, dried, and passed through a dry sieve for classification. , (Y _2.40 Gd _0.60 Ce _0.003 ) ₃ A second rare earth aluminate phosphor having a composition represented by Al ₅ O ₁₂ was prepared. The second particle size Dm ² of the second rare earth aluminate phosphor measured by the measuring method described later was 5.22 μm, and the second standard deviation Sd ² was 0.417.

Rare earth oxide particles Yttrium oxide particles having a third particle size Dm ³ of 0.923 μm and a _third standard deviation Sd ³ of _0.205 (composition formula is Y2O3, purity of yttrium oxide is 99.9 mass). %) Was used.

Particle Size and Standard Deviation For the 1st rare earth aluminate phosphor, 2nd rare earth aluminate phosphor, and rare earth oxide particles, a laser diffraction type particle size distribution measuring device (MASTER SIDER 3000, manufactured by MAVERN) by the laser diffraction scattering method. ) Is used to measure the ^first particle size distribution, the ^second particle size distribution, and the third particle size distribution, and the cumulative frequency is 50% in the volume-based particle size distribution. The three particle size Dm ³ , the first standard deviation Sd ¹ , the second standard deviation Sd ² , and the third standard deviation Sd ³ were determined based on the above equations (1) to (3).

Example 1
Step of preparing raw material mixture Weigh 25.1 g of the first rare earth aluminate phosphor, 2.80 g of the second rare earth aluminate phosphor, and 0.112 g of the rare earth oxide particles, and weigh the dispersant (dispersant). Floren G-700 (Kyoeisha Chemical Co., Ltd.) is a dispersant (Floren) when the total amount of the first rare earth aluminate phosphor, the second rare earth aluminate phosphor and the rare earth oxide particles is 100% by mass. G-700 (Kyoeisha Chemical Co., Ltd.) was added in an amount of 1% by mass, 42 g of ethanol was further added, and the mixture was mixed with a wet ball mill.
After removing the balls as the mixing medium from the mixture, ethanol was separated by an evaporator, and the obtained mixture was dried as described above to prepare a raw material mixture powder for a molded product. 1st rare earth phosphor, 2nd rare earth phosphor, and 2nd rare earth phosphor when the total amount of the 1st rare earth phosphor, the 2nd rare earth phosphor, and the rare earth oxide particles is 100% by mass. The contents of the body and the rare earth oxide particles are shown in Table 1.

Step of preparing the molded product The prepared raw material mixture powder is filled in a mold and pressed in a uniaxial direction with a pressure of 19.6 MPa (200 kgf / cm ² ) to form a cylindrical molded product having a diameter of 20 mm and a thickness of 20 mm. Obtained. The obtained molded product is placed in a packaging container, vacuum-packed, and further CIP-treated at 176 MPa using a cold isotropic pressure pressurizing device (manufactured by Kobe Steel, Ltd. (KOBELCO)) using water as a pressure medium. Was performed, and a molded product was prepared.

Step to obtain the first sintered body by the first heat treatment The prepared molded body is used in a firing furnace (manufactured by Marusho Electric Co., Ltd.) and has an atmospheric atmosphere (101.3 kPa, oxygen 20% by volume) and a temperature of 1700 ° C. The first heat treatment was carried out for 6 hours to obtain a first sintered body.

Step to obtain the second sintered body by the second heat treatment Using the hot isotropic pressure pressurizing device (manufactured by Kobe Steel Co., Ltd. (KOBELCO)), the obtained sintered body is used as a pressure medium using nitrogen gas. , Nitrogen gas atmosphere (99% by volume or more of nitrogen), 1700 ° C., 198 MPa, HIP treatment at 2 hours to obtain a second sintered body.

Annealing process The obtained second sintered body is held in an air atmosphere (101.3 kPa, oxygen 20% by volume) at a temperature of 1400 ° C. for 6 hours using a firing furnace (manufactured by Marusho Electric Co., Ltd.). , Annealed second sintered body was obtained.

Processing process and surface processing process The second sintered body that has been annealed is cut to an appropriate shape and size with a wire saw, and the surface of the cut piece is polished with a surface grinder to a thickness of 180 μm. A ceramic composite was obtained.

Example 2
In the process of preparing the raw material mixture, 24.8 g of the first rare earth aluminate phosphor, 2.77 g of the _second rare earth aluminate phosphor _, and 0.395 g of the rare earth oxide particles (Y2O3). And, respectively, were weighed to prepare a raw material mixture powder, and a ceramic composite was obtained in the same manner as in Example 1.

Comparative Example 1
In the step of preparing the raw material mixture, 27.7 g of the _first rare earth aluminate phosphor and _0.336 g of the rare earth oxide particles (Y2O3) are weighed, and the second rare earth aluminate fluorescence is used. A ceramic composite was obtained in the same manner as in Example 1 except that the raw material mixture powder was prepared without using a body.

Porosity The porosity of the ceramic composite is determined by performing image analysis on the SEM image of the surface of the ceramic composite obtained using SEM using image analysis software (ImageJ), and the first rare earth aluminic acid in the SEM image. Although the outer shape of the voids in the salt phosphor crystal phase can be confirmed, binarization processing is performed. For the measurement target that has been binarized, the total area (nm ² ) of the voids in the crystal phase of the first rare earth aluminate phosphor obtained by the binarization with respect to the total area (nm ² ) at the resolution of the SEM image is calculated. Expressed as a ratio (%). For example, when the resolution of the SEM image is 640 × 449, the total area of the surface of the ceramic complex is 2.8 × 10 ⁹ nm ² . The porosity of the ceramic composites of Examples and Comparative Examples was measured at a resolution having a total area of 2.8 × 10 ⁹ nm ² .

For each of the obtained ceramic composites of Examples and Comparative Examples, the light emitting device 100 shown in FIGS. 6A and 6B was produced as follows. The light emitting element 20 and the semiconductor element 70 were placed on the mounting substrate 10. Specifically, a light emitting device 20 formed by laminating a semiconductor layer on a sapphire substrate, having a thickness of about 0.11 mm, a planar shape of about 1.0 mm square, and a main wavelength of 450 nm. The light emitting element 2 and the semiconductor element 7 are arranged in a row so that the sapphire substrate side, which is a semiconductor growth substrate, serves as a light emitting surface, and a flip chip is mounted on the mounting substrate 10 conductive pattern using a conductive member 60 made of Au. did.
Next, a wavelength conversion member 30 in which a silicone resin is arranged as an adhesive 40 on the upper surface of the light emitting element 20 to form the ceramic composites of Examples and Comparative Examples in a plate shape, and the upper surface of the sapphire substrate of the light emitting element 20. Was glued.
Next, the covering member 50 was arranged around the light emitting element 20, the wavelength conversion member 30, and the semiconductor element 70. The covering member 50 was arranged along the side surface of the light emitting element 20 and the wavelength conversion member 30, and the semiconductor element 70 was completely embedded in the covering member 50. A dimethyl silicone resin was used as the resin 51 of the covering member 50, and titanium oxide particles having an average particle size of 0.28 μm were used as the light-reflecting material 52. The titanium oxide particles were contained in an amount of 60% by mass based on the resin 51. By such a step, the light emitting device 100 shown in FIGS. 6A and 6B was manufactured.
The light emitting device using each of the ceramic composites of Examples and Comparative Examples was evaluated as follows. The results are shown in Table 1.

Chromaticity coordinates (x, y), relative luminous flux (%), relative luminance (%), luminance / luminous flux ratio (L / F)
For each light emitting device using each ceramic composite of Examples and Comparative Examples, a luminous flux and CIE (International Lighting) were used using a light measurement system combining a spectrophotometric device (PMA-11, Hamamatsu Photonics Co., Ltd.) and an integrating sphere. Commission: Commission International de l'Eclairage) 1931 The chromaticity coordinates (x, y) in the chromaticity coordinate system of the chromaticity diagram were obtained. Luminance was determined using an imaging color luminance meter (Prometric I8, manufactured by Radiant Vision Systems). For the relative luminous flux and relative luminance, the luminous flux and luminance when the chromaticity coordinate x of each light emitting device using each ceramic composite is 0.323 (x = 0.323) are calculated using the reference line, and Comparative Example 1 The relative values of the luminous flux and the luminance of the light emitting device using each of the ceramic composites of the Examples were obtained, assuming that the luminous flux and the luminance of the light emitting device using the ceramic composite of the above were 100%. The reference line is a regression line derived from the correlation between the value of the chromaticity coordinate x of the emission color emitted from each light emitting device using each ceramic composite and the luminous flux or the luminance. In addition, the ratio (L / F) of the relative luminance to the relative luminous flux of the light emitting device using each ceramic complex was calculated. The higher the value of the ratio L / F of the relative brightness to the relative luminous flux, the stronger the light extracted in the direction perpendicular to the light emitting surface of the ceramic composite, and the ceramics emits light with high brightness by suppressing the spread. It can originate from the complex.

Half-value angle of light distribution (°)
The light distribution half value of the emitted light of each of the ceramic complexes of Examples and Comparative Examples was measured. Specifically, for each of the ceramic composites of Examples and Comparative Examples, CIE is recommended while energizing a current of 1 A to emit light and rotating the ceramic composite to change the directing angle using a goniometer. Under the conditions of Condition B, which is the average LED luminous intensity measurement, the luminous intensity of the emitted light of each ceramic composite was measured using a spectrophotometric device (PMA-11, manufactured by Hamamatsu Photonics Co., Ltd.). As for the directivity angle, the plane including the optical axis C was defined as the directivity angle of 0 °, and the range of plus or minus 90 ° from the optical axis C was defined as the directivity angle (°). In the emission spectrum of each ceramic composite described later, an angle range (half-value angle of light distribution (°)) in which the intensity of the emitted light emitted from the ceramic composite is ½ or more of the peak intensity was measured. The smaller the value of the half-value angle of the light distribution, the more the spread of the light is suppressed when the wavelength-converted light is emitted from the same surface as the incident surface of the excitation light.

Light distribution chromaticity difference (Δx)
The directivity chromaticity coordinates of the emitted light of each of the ceramic complexes of Examples and Comparative Examples were measured. Specifically, for each of the ceramic composites of Examples and Comparative Examples, CIE is recommended while energizing a current of 1 A to emit light and rotating the ceramic composite to change the pointing angle using a goniometer. Under the condition of Condition B, which is the average LED luminous intensity measurement, the directional chromaticity coordinates (x) of the emission color of the emitted light of each ceramic composite using a spectrophotometric device (PMA-11, manufactured by Hamamatsu Photonics Co., Ltd.). , Y) was measured. FIG. 7 is a schematic diagram showing a direction for measuring the light distribution chromaticity coordinates (x, y) of the emitted light of the ceramic complex. The angle between the light emitting surface emitting the emitted light of the ceramic composite from the optical axis C of the ceramic composite and the angle inclined in the horizontal direction was measured as the light distribution angle θ. The optical axis C of the ceramic composite is parallel to the z-axis in the normal direction with respect to the light emitting surface of the ceramic composite, refers to an axis passing through the central point of the ceramic composite, and has a light distribution angle of 0 °. Specifically, in the xy plane shown in FIG. 7, the z-axis with respect to the xy plane is set to a light distribution angle of 0 °, and the light distribution chromaticity is the xy plane from the z-axis to the xx plane. The angle θ tilted in the direction was defined as the light distribution angle θ. In the chromaticity coordinates of the CIE chromaticity diagram, the chromaticity coordinates (x ₀ , y ₀ ) with a light distribution angle of 0 ° and the light distribution chromaticity coordinates (x _θ , y _θ ) with a light distribution angle θ were measured. The difference Δx between the x-coordinate x0 with a light distribution angle of ₀ ° and the x-coordinate of the x-coordinate x60 with a light distribution angle of ₆₀ ° was defined as the light distribution chromaticity difference. The smaller the light distribution chromaticity difference Δx, the greater the difference in chromaticity between the emitted light from the ceramic composite visible at a light distribution angle of 0 ° and the emitted light from the ceramic composite visible at a light distribution angle of 60 °. This indicates that the color unevenness due to the change in the light distribution angle is reduced.

SEM Photographs Using SEM, SEM photographs of the ceramic complexes of Examples and Comparative Examples were obtained. FIG. 8 is an SEM photograph of the ceramic complex of Example 1, and FIG. 9 is an SEM photograph of the ceramic complex according to Comparative Example 1.

The ceramic complex according to Examples 1 and 2 had a lower relative luminous flux than the ceramic complex according to Comparative Example 1, but the incident light was diffused in the void by the first rare earth aluminate crystal phase C1 containing the void. The brightness was higher than that of the ceramic composite according to Comparative Example 1. The voids contained in the ceramic complex tend to suppress the spread of light while reducing the luminous flux of the light emitted from the ceramic complex. The ceramic complex according to Examples 1 and 2 contains a rare earth aluminate crystal phase C3 together with voids. The rare earth aluminate crystal phase contained in the ceramic composites according to Examples 1 and 2 has a different crystal structure from the first rare earth aluminate phosphor crystal phase C1 and the second rare earth aluminate phosphor crystal phase C2. Therefore, the spread of light is suppressed. Further, the refractive index of the rare earth aluminate crystal phase C3 contained in the ceramic composites according to Examples 1 and 2 is the first rare earth aluminate phosphor crystal phase C1 and the second rare earth aluminate phosphor crystal phase C2. Since the difference from the refractive index of is small, the light beam emitted from the ceramic composite does not decrease. Since the ceramic complex according to Examples 1 and 2 contains the rare earth aluminate crystal phase C3 together with the voids 4, it is possible to suppress the spread of light and the decrease of the luminous flux. Therefore, in the ceramic complexes according to Examples 1 and 2, the numerical value of the ratio L / F of the relative luminance to the relative luminous flux is higher than that in Comparative Example 1. From this result, in the ceramic complex according to Examples 1 and 2, the light taken out in the direction perpendicular to the light emitting surface of the ceramic complex is stronger than that of Comparative Example 1, and the emitted light having high brightness while suppressing the spread is made into ceramics. It was confirmed that it could be emitted from the complex.

The ceramic complex according to Examples 1 and 2 had a smaller half-value angle of light distribution than the ceramic complex according to Comparative Example 1, and the spread of the emitted light was suppressed. The ceramic composites according to Examples 1 and 2 have a smaller difference in chromaticity of light distribution Δx than the ceramic composite according to Comparative Example 1, have less deviation in chromaticity of emitted light, and have color unevenness due to a change in light distribution angle. It was reduced.

FIG. 8 is an SEM photograph of the ceramic complex according to Example 1. In the ceramic composite according to Example 1, the particles of the first rare earth aluminate phosphor or the particles of the first rare earth aluminate phosphor and the particles of the second rare earth aluminate phosphor are integrated. When the first rare earth aluminate phosphor crystal phase C1 is formed, there is a difference in the crystal growth rate due to the difference in particle size between the first particle size Dm ¹ and the second particle size Dm ² , and the void 4 is formed. It was formed. The ceramic complex according to Example 1 also contained a second rare earth aluminate phosphor crystal phase C2 containing no voids. The ceramic complex according to Example 1 also contained a rare earth aluminate crystal phase C3.

FIG. 9 is an SEM photograph of the ceramic complex according to Comparative Example 1. Since the ceramic composite according to Comparative Example 1 does not contain the second rare earth aluminate phosphor, the rate of crystal growth cannot be different, and the first rare earth aluminate phosphor crystal phase C1 containing voids is It was not formed. The ceramic composite according to Comparative Example 1 was composed of a second rare earth aluminate phosphor crystal phase C2 and a rare earth aluminate crystal phase C3 containing no voids.

The ceramic composite obtained by the manufacturing method according to the present disclosure can be used as a wavelength conversion member for a backlight of an in-vehicle or general lighting device or a liquid crystal display device in combination with an excitation light source.

C1: 1st rare earth aluminate phosphor crystal phase, C2: 2nd rare earth aluminate phosphor crystal phase, C3: rare earth aluminate crystal phase, 4: voids, 10: substrate, 20: light emitting element, 30: Frequency conversion member, 40: adhesive layer, 50: coating member, 60: conductive member, 70: semiconductor element, 100: light emitting device.

Claims (11)

The first particle size Dm ¹ , which has a cumulative frequency of 50% in the volume-based first particle size distribution by the laser diffraction scattering method, is within the range of 0.1 μm or more and 2.0 μm or less, and the first standard deviation in the first particle size distribution. The first rare earth aluminate phosphor having Sd ¹ in the range of 0.2 or more and 2.0 or less, and the second particle size Dm having a cumulative frequency of 50% in the volume-based second particle size distribution by the laser diffraction scattering method. ² is in the range of 2.1 μm or more and 20 μm or less, and the second standard deviation Sd ² in the second particle size distribution is in the range of 0.2 or more and 0.7 or less. The first rare earth aluminate, including the rare earth oxide particles, and the total amount of the first rare earth aluminate phosphor, the second rare earth aluminate phosphor, and the rare earth oxide particles is 100% by mass, and the first rare earth aluminate. The content of the phosphor is in the range of 69% by mass or more and 95.8% by mass or less, and the content of the second rare earth aluminate phosphor is in the range of 4% by mass or more and 30% by mass or less. To prepare a molded body obtained by molding a raw material mixture in which the content of rare earth oxide particles is in the range of 0.2% by mass or more and 10% by mass or less.
A method for producing a ceramic complex, which comprises first heat-treating the molded product at a temperature of 1200 ° C. or higher and 1800 ° C. or lower to obtain a first sintered body. In the step of preparing the molded body, the rare earth oxide particles have a third particle size Dm ³ having a cumulative frequency of 50% in the volume-based particle size distribution by the laser diffraction / scattering method within a range of 0.5 μm or more and 5 μm or less. The method for producing a ceramic composite according to claim 1, wherein the third standard deviation Sd ³ in the particle size distribution is in the range of 0.2 or more and 1.0 or less. The method for producing a ceramic composite according to claim 1 or 2, wherein in the step of preparing the molded body, the first rare earth aluminate phosphor is obtained by a coprecipitation method. After the step of obtaining the first sintered body, the first sintered body is further subjected to a second heat treatment at a temperature of 1500 ° C. or higher and 1800 ° C. or lower by hot isotropic pressure pressurization (HIP) treatment, and the second sintering is performed. The method for producing a ceramic composite according to any one of claims 1 to 3, which comprises obtaining a body. The method for producing a ceramic complex according to claim 4, wherein in the step of obtaining the second sintered body, the second sintered body is annealed in an oxygen-containing atmosphere. In the step of preparing the molded body, the first rare earth aluminate phosphor and the second rare earth aluminate phosphor are at least one selected from the group consisting of Y, La, Lu, Gd and Tb. The rare earth element Ln ¹ , Ce, and Al may be contained, and at least a part of the Al may be replaced with at least one element M ¹ selected from Ga and Sc, if necessary. The total molar ratio of Ln ¹ and Ce is 3, the total molar ratio of Al and the element M ¹ is the product of variables k and 5 of 0.95 or more and 1.05 or less, and the molar ratio of Ce is 0. The method for producing a ceramic composite according to any one of claims 1 to 5, which has a first composition which is a product of a variable n and 3 having a variable n of .003 or more and 0.030 or less. In the step of preparing the molded body, the rare earth element Ln ¹ , Ce, Al and the element M ¹ have the following formulas for the first rare earth phosphor and the second rare earth phosphor. The method for producing a ceramic composite according to any one of claims 1 to 6, which satisfies the composition formula represented by I).
(Ln ¹ _{1-n Cen} ) ₃ (Al _1-m M ¹ _m ) _5k O ₁₂ (I)
(In the formula (I), m, n, and k satisfy 0 ≦ m ≦ 0.1, 0.003 ≦ n ≦ 0.030, and 0.95 ≦ k ≦ 1.05, respectively.) Claims 1 to 7 include, in the step of preparing the molded body, the rare earth oxide particles containing at least one rare earth element Ln ² selected from the group consisting of Y, La, Lu, Gd, Tb and Ce. The method for producing a ceramic composite according to any one of the above items. A ceramics composite containing a first rare earth aluminate phosphor crystal phase containing voids, a second rare earth aluminate phosphor crystal phase not containing voids, and a rare earth aluminate crystal phase. The ceramic composite according to claim 9, wherein the first rare earth aluminate phosphor crystal phase or the second rare earth aluminate phosphor crystal phase has a first composition represented by the following formula (I).
(Ln ¹ _{1-n Cen} ) ₃ (Al _1-m M ¹ _m ) _5k O ₁₂ (I)
(In the above formula (I), Ln ¹ is at least one rare earth element selected from the group consisting of Y, La, Lu, Gd and Tb, and M ¹ is at least 1 selected from Ga and Sc. It is a species element, and m, n, and k satisfy 0 ≦ m ≦ 0.1, 0.003 ≦ n ≦ 0.030, and 0.95 ≦ k ≦ 1.05, respectively.) The ceramic complex according to claim 9 or 10, wherein the rare earth aluminate crystal phase has a second composition represented by the following formula (II).
Ln ² Al _1-p M ² _p O ₃ (II)
(In the above formula (II), Ln ² is at least one rare earth element selected from the group consisting of Y, La, Lu, Gd, Tb and Ce, and M ² is from the group consisting of Ga and Sc. It is at least one element to be selected, and p satisfies 0 ≦ p ≦ 0.8.)

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