Wavelength conversion member, method for manufacturing the same, and light-emitting device

Abstract

To provide a wavelength conversion member with improved heat dissipation and excellent wavelength conversion efficiency accompanying a higher-energy trend, and to provide a method of producing the same and a light emitting device.SOLUTION: A wavelength conversion member 100 comprises: a light-transmissive base material 10; and a single-layer phosphor layer 20 which is provided on one main surface 12 of the base material 10 and is formed by at least a first phosphor particle 22 and a light-transmissive ceramic 24 that bonds the first phosphor particles 22 to each other and the base material 10 and the first phosphor particles 22, wherein an average particle diameter D1 of the first phosphor particles 22 in the phosphor layer 20 is 5 μ m or more and 30 μ m or less, and in the phosphor layer 20, an average particle diameter D2 of the first phosphor particles 22 in a base material side area 26 of 1 / 3 of the average film thickness of the phosphor layer 20 perpendicular to the main surface 12 on the base material 10 side is larger than the average particle diameter D1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wavelength conversion member, a method for manufacturing the same, and a light-emitting device.

Background Art

[0002] Light-emitting devices using a wavelength conversion member that emits light, which is irradiated from a light source such as an LED (Light Emitting Diode) or LD (Laser Diode) that is a light-emitting element, as converted light having a wavelength different from the wavelength of the light source by a phosphor layer are known. In recent years, applications using LDs as light sources, which have high energy efficiency and are easy to adapt to miniaturization and higher output, are increasing.

[0003] As such wavelength conversion members, structures in which a phosphor is dispersed in a resin typified by epoxy, silicone, or the like are widely used. However, as the output of light sources increases, scorching or discoloration of the resin occurs, leading to degraded characteristics and shortened service life. To address such issues, wavelength conversion members composed only of inorganic materials using an inorganic binder instead of resin have been devised, and the problem of heat resistance has been resolved even when used with high-energy light sources.

[0004] Patent Document 1 describes a light-emitting device in which a plurality of light-emitting elements made of LEDs are mounted on a substrate, a wavelength conversion member is arranged over the light-emitting elements with a space interposed between the wavelength conversion member and the light-emitting elements, the wavelength conversion member includes a particulate phosphor material and a binder, and the binder is obtained by reacting a binder raw material containing at least one member selected from the group consisting of oxide precursors that become oxides through hydrolysis or oxidation, silicic acid compounds, silica, and amorphous silica at normal temperature, or by subjecting the binder raw material to heat treatment at a temperature of 500°C or lower.

[0005] Patent Document 2 describes a light-emitting device comprising a light-emitting element that emits excitation light on a substrate and a wavelength converter that converts the excitation light into visible light using a phosphor, wherein the visible light is used as output light, and the phosphor is made of a semiconductor with a bandgap energy of 1.6 eV or less. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2015-038960 [Patent Document 2] Japanese Patent Publication No. 2005-285800 [Overview of the project] [Problems that the invention aims to solve]

[0007] The wavelength conversion member described in Patent Document 1 has been made more responsive to higher output light sources by using an inorganic binder as the binder constituting the phosphor layer. However, the structure and state of the produced phosphor layer are thought to differ depending on the manufacturing conditions of the phosphor ink printed on the surface of the substrate, which may affect luminescence characteristics such as brightness, color tone, and adhesion to the substrate. However, Patent Document 1 does not describe the manufacturing conditions of the phosphor ink.

[0008] Furthermore, the wavelength conversion layer described in Patent Document 2 is in close contact with the light-emitting element, which may pose a problem for heat dissipation as the output of the light-emitting element increases. Also, the phosphor particles used are nanoparticles, and improving the luminescence characteristics in wavelength conversion members using large-particle phosphor particles has not been considered. In addition, although the particle size for each wavelength conversion layer is described, there is no mention of the structure of the single-layer portion.

[0009] This invention has been made in view of these circumstances, and aims to provide a wavelength conversion member with improved heat dissipation and excellent wavelength conversion efficiency, a method for manufacturing the same, and a light-emitting device. [Means for solving the problem]

[0010] (1) In order to achieve the above objective, the wavelength conversion member of the present invention employs the following means. That is, the wavelength conversion member of an application example of the present invention is a wavelength conversion member comprising: a light-transmitting substrate; a single-layer phosphor layer provided on one main surface of the substrate and formed of at least first phosphor particles and light-transmitting ceramics that bond the first phosphor particles to each other and to the substrate and to the first phosphor particles, wherein the average particle diameter D1 of the first phosphor particles in the phosphor layer is 5 μm or more and 30 μm or less, and the phosphor layer is characterized in that the average particle diameter D2 of the first phosphor particles in the substrate-side region of the average film thickness of the phosphor layer perpendicular to the main surface is greater than the average particle diameter D1.

[0011] In this way, by increasing the average particle diameter D2 in the substrate-side region within a single-layer phosphor layer, it is possible to create a state where a large number of first phosphor particles with an average particle diameter D1 or greater are distributed on the substrate side, thereby improving the luminescence efficiency. Furthermore, the heat dissipation of the phosphor layer can be improved.

[0012] (2) Furthermore, in the wavelength conversion member of the application example of (1) above, the wavelength conversion member further comprises a single-layer second phosphor layer provided on the surface facing the main surface of the phosphor layer, which is formed of at least second phosphor particles and a second translucent ceramic that bonds the second phosphor particles to each other and to the phosphor layer and to the second phosphor particles, wherein the average particle diameter D3 of the second phosphor particles in the second phosphor layer is 5 μm or more and 30 μm or less.

[0013] A thinner phosphor layer has lower thermal resistance, which helps suppress the decrease in luminescence intensity (temperature quenching) caused by heat accumulation in the phosphor layer when irradiated with light from a light source. However, in the wavelength conversion member of the application example in (1), the distribution of phosphor particles in the phosphor layer is intentionally varied, and if the thickness of the phosphor layer is reduced, wavelength conversion to the light source may not be sufficient, potentially causing localized color unevenness. Therefore, by laminating a second phosphor layer on top of the phosphor layer in this way, bleeding and pinholes around the edges of the phosphor layer are suppressed, thereby suppressing the occurrence of color unevenness. Furthermore, if the second phosphor layer has a normal distribution of phosphor particles, the distribution of voids in the second phosphor layer also becomes uniform, further suppressing the occurrence of localized color unevenness.

[0014] (3) Furthermore, in the wavelength conversion member of the application example of (2) above, the second phosphor layer is characterized in that the average particle diameter D4 of the second phosphor particles in the phosphor layer-side region of the average thickness of the second phosphor layer perpendicular to the main surface is greater than the average particle diameter D3.

[0015] Thus, because the second phosphor layer has the same characteristics as the phosphor layer, This method suppresses bleeding around the edges and pinholes, and since it allows the use of the same phosphor ink as the phosphor layer in the application example of (1), the manufacturing process can be simplified.

[0016] (4) Furthermore, an example of the present invention is a light-emitting device that comprises a light-emitting element that emits light of a specific range of wavelengths, and a wavelength conversion member as described in any of (1) to (3) above.

[0017] The wavelength conversion member of the present invention offers improved heat dissipation in response to high energy levels and excellent wavelength conversion efficiency. Therefore, a light-emitting device using this member can be used as a light-emitting device capable of handling high output levels of light-emitting elements such as LDs.

[0018] (5) Furthermore, a method for manufacturing a wavelength conversion member in an application example of the present invention is a method for manufacturing a wavelength conversion member, characterized by comprising the steps of: preparing a light-transmitting substrate; adjusting the viscosity of a phosphor ink obtained by mixing first phosphor particles and an inorganic binder at 25°C to 10 dPa·s or more and less than 35 dPa·s; applying the phosphor ink to the surface of the substrate; and forming a phosphor layer by heat-treating the applied phosphor ink at a temperature of 500°C or less.

[0019] By adjusting the viscosity of the phosphor ink to the above range and applying it to the substrate, the flow of the phosphor ink causes the relatively large first phosphor particles to be biased towards the substrate side. Subsequently, by performing heat treatment, it is possible to create a state in which the first phosphor particles having a particle size of D1 or larger than the average particle size of the entire phosphor layer are largely distributed on the substrate side, thereby increasing the average particle size D2 of the substrate-side region within the single-layer phosphor layer. As a result, the luminescence efficiency of the wavelength conversion member can be improved, and the heat dissipation of the phosphor layer can be improved.

[0020] (6) Furthermore, a method for manufacturing a wavelength conversion member according to an application example of the present invention is a method for manufacturing a wavelength conversion member, comprising the steps of: preparing a light-transmitting substrate; adjusting the viscosity of a first phosphor ink, obtained by mixing first phosphor particles and an inorganic binder, at 25°C to 10 dPa·s or more and less than 35 dPa·s; applying the first phosphor ink to the surface of the substrate; drying the first phosphor ink; adjusting the viscosity of a second phosphor ink, obtained by mixing second phosphor particles and a second inorganic binder, at 25°C to 10 dPa·s or more and 75 dPa·s or less; applying the second phosphor ink to the surface of the layer to which the first phosphor ink has been applied; and forming a phosphor layer and a second phosphor layer by heat-treating the applied first phosphor ink and second phosphor ink at a temperature of 500°C or less.

[0021] Thereby, it is possible to manufacture a wavelength conversion member in which a single-layer second phosphor layer is laminated on a phosphor layer in which the average particle diameter D2 in the base material side region is increased within the single-layer phosphor layer. As a result, bleeding at the outer periphery of the phosphor layer and pinholes are suppressed, and a wavelength conversion member capable of suppressing the occurrence of color unevenness can be obtained.

Effects of the Invention

[0022] The wavelength conversion member and the light-emitting device of the present invention can improve the luminous efficiency and can improve the heat dissipation property of the phosphor layer. In addition, the method for manufacturing a wavelength conversion member of the present invention can produce a wavelength conversion member that is excellent in luminous efficiency and heat dissipation property of the phosphor layer.

Brief Description of the Drawings

[0023] [Figure 1] It is a schematic cross-sectional view showing an example of the cross-sectional structure of the wavelength conversion member according to the embodiment of the present invention. [Figure 2] It is a schematic cross-sectional view showing the base material side region of the wavelength conversion member of Figure 1. [Figure 3] It is a schematic cross-sectional view showing a modified example of the cross-sectional structure of the wavelength conversion member according to the embodiment of the present invention. [Figure 4] It is a schematic cross-sectional view showing the base material side region and the phosphor layer side region of the wavelength conversion member of Figure 3. [Figure 5] It is a conceptual diagram showing a part of an example of the light-emitting device according to the embodiment of the present invention. [Figure 6] It is a flowchart showing an example of the method for manufacturing a wavelength conversion member according to the embodiment of the present invention. [Figure 7] It is a flowchart showing a modified example of the method for manufacturing a wavelength conversion member according to the embodiment of the present invention. [Figure 8] It is a table showing the manufacturing conditions of the wavelength conversion members of Examples and Comparative Examples and the results of each evaluation test.

Mode for Carrying Out the Invention

[0024] Next, embodiments of the present invention will be described with reference to the drawings. To facilitate understanding of the explanation, the same reference numeral is used for identical components in each drawing, and redundant explanations are omitted. Note that the sizes of each component in the configuration diagrams are conceptual representations and do not necessarily represent actual dimensional ratios.

[0025] [Configuration of wavelength conversion components] Figure 1 is a schematic cross-sectional view showing an example of the cross-sectional structure of a wavelength conversion member 100 according to an embodiment of the present invention. In the wavelength conversion member 100 according to an embodiment of the present invention, a phosphor layer 20 is formed on a substrate 10. The wavelength conversion member 100 transmits incident light irradiated from a light source and generates light of different wavelengths when excited by the incident light. For example, while transmitting blue incident light, it emits green and red or yellow converted light converted by the phosphor layer 20, and can convert the converted light and incident light together, or use only the converted light, to light of various colors.

[0026] The shape of the substrate 10 can be any shape that is applicable to the light-emitting device 200, and may be various shapes such as circular, rectangular, elliptical, or polygonal. For example, a circular substrate 10 may have an annular phosphor layer 20 formed on it.

[0027] The substrate 10 is translucent. The material of the substrate 10 can be selected as appropriate. Since the wavelength conversion member 100 of the present invention is used to transmit incident light or converted light from a light-emitting element, translucent inorganic materials such as sapphire or glass can be used. It is particularly preferable to use sapphire, which has high thermal conductivity, as this suppresses the deterioration of the phosphor's properties due to temperature rise by suppressing heat accumulation in the phosphor layer 20.

[0028] The phosphor layer 20 is provided as a film on the main surface 12 of the substrate 10 and is formed as a single layer of at least first phosphor particles 22 and translucent ceramics 24. The translucent ceramics 24 bond the first phosphor particles 22 to each other and also bond the first phosphor particles 22 to the substrate 10. As a result, when irradiated with high-energy-density light, heat can be efficiently dissipated because it is bonded to the substrate 10 which functions as a heat dissipation material, and thermal quenching of the phosphor can be suppressed. The phosphor layer 20 may contain voids 40. A single-layer phosphor layer refers to a phosphor layer in which, in a cross-section along the thickness direction of the phosphor layer, there is no boundary with other phosphor layers within that layer.

[0029] The average thickness of the phosphor layer 20 is preferably 15 μm or more and 300 μm or less, and more preferably 50 μm or more and 200 μm or less. If the average thickness of the phosphor layer 20 is less than 15 μm, there will be areas in the phosphor layer 20 where the probability of phosphor particles being present decreases in various optical paths, making it difficult to obtain uniform irradiation light. On the other hand, if it is thicker than 300 μm, there is a risk of thermal quenching due to heat accumulation in the phosphor layer 20, which can be a problem, especially in high-power applications. The average thickness of the phosphor layer 20 is preferably greater than 1.5 times the average particle diameter of the phosphor particles forming the phosphor layer 20.

[0030] The average film thickness of the phosphor layer 20 can be determined by image analysis of SEM images (for example, at 1000x magnification). In the SEM image of the cross-section of the substrate 10 in a direction perpendicular to the main surface 12, 10 perpendicular lines are drawn at equal intervals, the distance from the top surface of the phosphor layer 20 to the main surface 12 is measured, and the average value of the lengths of the 10 lines is taken as the average film thickness of the phosphor layer 20.

[0031] The first phosphor particles 22 forming the phosphor layer 20 represent one type of phosphor particle that generates converted light of a specific wavelength. The phosphor layer 20 may also contain other types of phosphor particles besides the first phosphor particles 22.

[0032] The average particle diameter D1 of the first phosphor particles 22 in the phosphor layer 20 is between 5 μm and 30 μm. When the average particle diameter D1 of the first phosphor particles 22 is 5 μm or more, the emission intensity of the converted light increases, and consequently, the emission intensity of the wavelength conversion member 100 increases. When it is 30 μm or less, the thickness of the phosphor layer 20 can be easily adjusted, and the risk of detachment of the first phosphor particles 22 can be reduced. In addition, the temperature of individual first phosphor particles 22 can be kept low, and thermal quenching can be suppressed.

[0033] In the phosphor layer 20, the average particle diameter D2 of the first phosphor particles 22 in the substrate-side region 26, which is one-third of the average film thickness of the phosphor layer 20 perpendicular to the main surface 12 on the substrate 10 side, is greater than the average particle diameter D1. This improves the luminescence efficiency of the first phosphor particles 22 and improves the heat dissipation of the phosphor layer 20. An average particle diameter D2 greater than the average particle diameter D1 means that the average particle diameter D2 is 1.1 times or more the average particle diameter D1. The average particle diameter can be confirmed by image analysis of an SEM image. In this specification, the average particle diameter is defined as the circular equivalent diameter relative to the average value of the cross-sectional areas obtained from the cumulative distribution of particles recognized as phosphor particles, calculated by performing image analysis such as binarization on an SEM image (e.g., 1000x magnification) of a cross-section of the substrate 10 perpendicular to the main surface 12. Particles that straddle the edges in the planar direction of the SEM image are not included in the calculation of the average particle diameter. Furthermore, it is preferable to perform the measurement using images from multiple locations (e.g., three or more) at random intervals to obtain an overall average particle size.

[0034] Figure 2 is a schematic cross-sectional view showing the substrate-side region 26 of the wavelength conversion member 100 in Figure 1. As shown in Figure 2, when there are irregularities on the surface of the phosphor layer 20 (the surface 28 of the phosphor layer 20 facing the main surface of the substrate), the substrate-side region 26 is defined as follows. First, the average film thickness of the phosphor layer 20 is determined in the cross-section, and a straight line parallel to the main surface 12 that determines the average film thickness is drawn. Next, a straight line parallel to the main surface 12 is drawn at a position with a thickness of 1 / 3 of the average film thickness from the main surface 12. The region from this straight line to the main surface 12 is defined as the substrate-side region 26. The average particle diameter D2 of the substrate-side region 26 is determined by calculating the cross-sectional area of ​​each first phosphor particle 22 whose cross-section is included in the substrate-side region 26, and particles whose cross-sectional area is included in the substrate-side region 26 for 1 / 2 or more of the area (hereinafter referred to as "1 / 2 or more particles") are considered as the first phosphor particles 22 present in the substrate-side region 26 for which the average particle diameter D2 is calculated. Furthermore, when determining the average particle diameter D2, the cross-sectional area of ​​particles that make up more than half of the total is used. That is, the cross-sectional area of ​​the portion that extends beyond the straight line at the 1 / 3 position of the average film thickness, away from the substrate-side region 26, is also included. The average particle diameter D2 is then defined as the circular equivalent diameter relative to the average value of the cross-sectional areas obtained from the cumulative distribution of the first phosphor particles 22 that are determined to be present in the substrate-side region 26. Note that when determining the average particle diameter D2, particles that straddle the edges in the planar direction of the SEM image are not included in the calculation of the average particle diameter. In addition, it is preferable to check multiple images (for example, three or more) at random locations to obtain the overall average particle diameter.

[0035] Furthermore, if the phosphor layer 20 contains phosphor particles of a different type than the first phosphor particles 22, the average particle diameter of those phosphor particles in the entire phosphor layer 20 and the average particle diameter in the substrate-side region 26 may be greater in the substrate-side region 26, or there may be no such relationship. This is because if some of the phosphor particles exhibit the above bias, those phosphor particles will have better luminescence efficiency and higher heat dissipation. Such a configuration can be achieved by making the average particle diameter and particle size distribution different for the first phosphor particles 22 and the other type of phosphor particles.

[0036] Specifically, for example, suppose the phosphor layer 20 contains YAG-based phosphor particles as the first phosphor particles 22 and LAG-based phosphor particles as other phosphor particles. In this case, if the condition is met that the average particle diameter D2 of the substrate-side region 26 of the YAG-based phosphor particles is greater than the overall average particle diameter D1 of the YAG-based phosphor particles, then the average particle diameter D2' of the substrate-side region 26 of the LAG-based phosphor particles may be greater than or less than the overall average particle diameter D1' of the LAG-based phosphor particles.

[0037] The first phosphor particles 22 can be, for example, yttrium-aluminum-garnet phosphors (YAG phosphors) and lutetium-aluminum-garnet phosphors (LAG phosphors). In addition, the first phosphor particles 22 can be selected from the following materials depending on the design of the color to be emitted. For example, BaMgAl 10 O 17 Blue phosphors such as :Eu, ZnS:Ag,Cl, BaAl2S4:Eu or CaMgSi2O6:Eu, Zn2SiO4:Mn, (Y,Gd)BO3:Tb, ZnS:Cu,Al, (M1)2SiO4:Eu, (M1)(M2)2S:Eu, (M3)3Al5O 12 Examples of yellow or green phosphors include Ce, SiAlON:Eu, CaSiAlON:Eu, (M1)Si2O2N:Eu, or (Ba,Sr,Mg)2SiO4:Eu,Mn; yellow, orange, or red phosphors such as (M1)3SiO5:Eu or (M1)S:Eu; and red phosphors such as (Y,Gd)BO3:Eu, Y2O2S:Eu, (M1)2Si5N8:Eu, (M1)AlSiN3:Eu, or YPVO4:Eu. In the above chemical formulas, M1 includes at least one from the group consisting of Ba, Ca, Sr, and Mg; M2 includes at least one from Ga and Al; and M3 includes at least one from the group consisting of Y, Gd, Lu, and Te. The first phosphor particles 22 described above are merely an example, and the first phosphor particles 22 used in the wavelength conversion member 100 are not necessarily limited to those described above.

[0038] Translucent ceramics 24 are formed by the hydrolysis or oxidation of an inorganic binder and are composed of translucent inorganic materials. Translucent ceramics 24 are composed of, for example, silica (SiO2) and aluminum phosphate. Furthermore, because translucent ceramics 24 are translucent, they can transmit light from a light source (incident light) or converted light. Since translucent ceramics 24 are made of inorganic materials, their heat resistance is improved, and deterioration is less likely to occur even when irradiated with high-energy light such as LDs. Examples of inorganic binders that can be used include ethyl silicate and aqueous aluminum phosphate solutions.

[0039] A translucent material is defined as a material that, when light in the visible light wavelength range (λ=380~780nm) is incident perpendicularly on a 0.5 mm thick object, has the characteristic that the radiant flux of light that exits from the opposite side exceeds 80% of the incident light.

[0040] It is preferable that the phosphor layer 20 does not have mesh marks on its surface. If mesh marks are present on the phosphor layer 20, cracks and pinholes may occur due to localized changes in film thickness. Mesh marks refer to the lattice-like pattern of the mesh that remains on the surface of the phosphor layer 20 when a high-viscosity phosphor ink is used during screen printing. Since the phosphor layer 20 of the present invention uses a low-viscosity phosphor ink, it hardly produces any mesh marks. Mesh marks can be confirmed by shining light on the phosphor layer 20.

[0041] Figure 3 is a schematic cross-sectional view showing a modified example of the cross-sectional structure of the wavelength conversion member 100 according to an embodiment of the present invention. As shown in Figure 3, the wavelength conversion member 100 according to an embodiment of the present invention preferably further comprises a single-layer second phosphor layer 30 provided on a surface 28 of the phosphor layer 20 facing the main surface of the substrate, and formed of at least second phosphor particles 32 and a second translucent ceramic 34 that bonds the second phosphor particles 32 to each other and to the phosphor layer 20 and to the second phosphor particles 32. This suppresses bleeding and pinholes on the outer edge of the phosphor layer 20 and suppresses the occurrence of color unevenness. Another phosphor layer may be laminated on the surface 38 of the second phosphor layer.

[0042] The overall average film thickness of the combined phosphor layer 20 (first phosphor layer) and the second phosphor layer 30 is preferably 15 μm or more and 300 μm or less, and more preferably 50 μm or more and 200 μm or less.

[0043] The overall average film thickness of the first phosphor layer 20 and the second phosphor layer 30 combined, and the average film thickness of the second phosphor layer 30 alone, can be confirmed by image analysis of SEM images. In an SEM image of a cross-section of the substrate 10 perpendicular to the main surface 12 (for example, at 1000x magnification), ten perpendicular lines are drawn at equal intervals, and the distance from the top surface of the second phosphor layer 30 to the main surface 12 is measured. The average value of the lengths of these ten lines is taken as the overall average film thickness of the first phosphor layer 20 and the second phosphor layer 30 combined. Furthermore, for the same ten perpendicular lines, the distance from the top surface of the second phosphor layer 30 to the interface between the first phosphor layer 20 and the second phosphor layer 30 (the surface 28 of the first phosphor layer 20 facing the main surface of the substrate) is measured, and the average value of the lengths of these ten lines is taken as the average film thickness of the second phosphor layer 30 alone.

[0044] The second phosphor particles 32 forming the second phosphor layer 30 represent one type of phosphor particle that generates converted light of a specific wavelength. The second phosphor layer 30 may also contain other types of phosphor particles besides the second phosphor particles 32.

[0045] The average particle diameter D3 of the second phosphor particles 32 in the second phosphor layer 30 is preferably 5 μm or more and 30 μm or less. When the average particle diameter D3 of the second phosphor particles 32 is 5 μm or more, the emission intensity of the converted light increases, and consequently the emission intensity of the wavelength conversion member 100 increases. When it is 30 μm or less, the thickness of the second phosphor layer 30 can be easily adjusted, and the risk of detachment of the second phosphor particles 32 can be reduced. In addition, the temperature of individual second phosphor particles 32 can be kept low, and thermal quenching can be suppressed. The average particle diameter D3 of the second phosphor particles 32 may be the same as or different from the average particle diameter D1 of the first phosphor particles 22. The average particle diameter D3 is determined by performing image analysis, such as binarization, on an SEM image (e.g., 1000x magnification) of a cross-section of the substrate 10 perpendicular to the main surface 12. The cross-sectional area of ​​particles recognized as second phosphor particles 32 within the second phosphor layer 30 is calculated from the image, and the circular equivalent diameter of the average value of the cross-sectional areas obtained from the cumulative distribution is defined as the average particle diameter D3. When determining the average particle diameter D3, particles that straddle the edges in the planar direction of the SEM image are not included in the calculation of the average particle diameter. Furthermore, it is preferable to perform the measurement using images from multiple locations (e.g., three or more) at random intervals to obtain an overall average particle diameter.

[0046] In the second phosphor layer 30, it is preferable that the average particle diameter D4 of the second phosphor particles 32 in the phosphor layer-side region 36, which is the 1 / 3 of the average film thickness of the second phosphor layer 30 perpendicular to the main surface 12 on the phosphor layer 20 side, is greater than the average particle diameter D3. An average particle diameter D4 greater than the average particle diameter D3 means that the average particle diameter D4 is 1.1 times or more the average particle diameter D3.

[0047] Figure 4 is a schematic cross-sectional view showing the substrate-side region 26 and the phosphor layer-side region 36 of the wavelength conversion member 100 in Figure 3. As shown in Figure 4, if there are irregularities on the surface of the first phosphor layer 20 (the surface 28 of the first phosphor layer 20 facing the main surface of the substrate) or the surface 38 of the second phosphor layer, the phosphor layer-side region 36 is defined as follows. First, the average film thickness of the first phosphor layer 20 is determined in the cross-section, and a straight line parallel to the main surface 12 that determines the average film thickness is drawn. Next, the average film thickness of the second phosphor layer 30 is determined in the cross-section, and a straight line parallel to the main surface 12 that determines the average film thickness of the second phosphor layer 30 is drawn using the straight line that determines the average film thickness of the first phosphor layer 20 as a reference. Next, a straight line parallel to the main surface 12 is drawn from the straight line that determines the average film thickness of the first phosphor layer 20 to a position at a thickness of 1 / 3 of the average film thickness of the second phosphor layer 30. The region from the straight line to the surface 28 facing the main surface of the substrate of the first phosphor layer 20 is defined as the phosphor layer side region 36. The average particle diameter D4 of the phosphor layer side region 36 is determined by calculating the cross-sectional area of ​​each second phosphor particle 32 whose cross-section is included in at least a portion of the phosphor layer side region 36, and selecting particles whose cross-sectional area is included in the phosphor layer side region 36 by half or more (hereinafter referred to as "1 / 2 or more particles") as the phosphor particles for which the average particle diameter D4 is calculated. When determining the average particle diameter D4, the cross-sectional area of ​​the "1 / 2 or more particles" is used. That is, the cross-sectional area of ​​the portion that extends beyond the straight line at the 1 / 3 position of the average film thickness to the opposite side of the phosphor layer side region 36 is also included. The average particle diameter D4 is defined as the circle equivalent diameter for the average value of the cross-sectional area obtained from the cumulative distribution of the second phosphor particles 32 determined to be present in the phosphor layer side region 36. Furthermore, when determining the average particle diameter D4, particles that straddle the edges of the SEM image in the planar direction are not included in the calculation of the average particle diameter. In addition, it is preferable to check multiple images (e.g., three or more) at random locations to obtain the overall average particle diameter.

[0048] In the second phosphor layer 30, the average particle diameter D3 of the second phosphor particles 32 may be random in a cross-section perpendicular to the main surface 12. Randomness of the average particle diameter D3 of the second phosphor particles 32 means that the average particle diameter D4 in the phosphor layer region 36, which is the 1 / 3 of the thickness of the second phosphor layer 30 on the phosphor layer 20 side perpendicular to the main surface 12, is less than 1.1 times the average particle diameter D3. In this case, it is preferable that the average particle diameter D4 is 0.9 times or more the average particle diameter D3. This results in a more uniform distribution of voids 40 in the second phosphor layer 30, further suppressing the occurrence of localized color unevenness.

[0049] The second phosphor particles 32 can be any of the various phosphor particles shown in the example of the first phosphor particles 22 above. Furthermore, since the first phosphor particles 22 above are just an example, the second phosphor particles 32 used in the wavelength conversion member 100 are not necessarily limited to those shown above. When the second phosphor layer 30 is to be given the role of auxiliary wavelength conversion when there is variation in the converted light of the first phosphor layer 20, it is preferable that the type of second phosphor particles 32 is the same as that of the first phosphor particles 22. However, if such a role is not considered, the type of second phosphor particles 32 may be the same as or different from that of the first phosphor particles 22.

[0050] The second translucent ceramic 34 is formed by hydrolysis or oxidation of an inorganic binder and is composed of a translucent inorganic material. The second translucent ceramic 34 is composed of, for example, silica (SiO2) and aluminum phosphate. As the inorganic binder, for example, ethyl silicate, an aqueous solution of aluminum phosphate, etc. are used. It is preferable that the second translucent ceramic 34 is formed of the same type of material as the translucent ceramic 24, but it may be formed of a different type of material.

[0051] It is preferable that the second phosphor layer 30 does not have mesh marks on its surface. If mesh marks are present on the second phosphor layer 30, cracks and pinholes may occur due to localized changes in film thickness. When forming the second phosphor layer 30 using a high-viscosity phosphor ink, care must be taken to prevent the formation of mesh marks, such as adjusting the time from application of the phosphor ink to drying or heat treatment. Mesh marks can be confirmed by shining light on the second phosphor layer 30.

[0052] [Configuration of the light-emitting device] Figure 5 is a conceptual diagram showing a part of an example of a light-emitting device according to an embodiment of the present invention. The light-emitting device 200 comprises a light source (light-emitting element) 150 and a wavelength conversion member 100. The light source 150 is a light-emitting element that generates light source light of a specific range of wavelengths, and can be an LED or an LD, for example. The wavelength conversion member 100 can efficiently convert wavelengths even at high power, so it is preferable that the light source 150 is an LD. The light source 150 may be placed on the substrate 10 side of the wavelength conversion member 100. This simplifies the configuration of the light-emitting device 200. In addition, the light source light may be irradiated onto the wavelength conversion member 100 via a mirror or the like. This increases the degree of freedom in the arrangement of the light source 150 of the light-emitting device 200.

[0053] The wavelength conversion member 100 of the present invention offers improved heat dissipation and excellent wavelength conversion efficiency in response to high energy levels, and can therefore be used as a light-emitting device 200 capable of handling high output light-emitting elements such as LDs. Such a light-emitting device 200 can be applied to laser illumination, headlights, projectors, and the like.

[0054] [Manufacturing method for wavelength conversion components] An example of a method for manufacturing a wavelength conversion member will be described. Figure 6 is a flowchart showing an example of a method for manufacturing a wavelength conversion member according to an embodiment of the present invention. First, a base material is prepared by processing raw materials and forming it into a predetermined shape (Step S1).

[0055] In addition to preparing the substrate, a phosphor ink (phosphor paste) is prepared by mixing the first phosphor particles with an inorganic binder (step S2). To prepare the phosphor ink, first, first phosphor particles having a predetermined average particle size are prepared. Depending on the design of the wavelength conversion member, various types of first phosphor particles can be used. One or more types of phosphor particles other than the first phosphor particles may also be used.

[0056] Next, the prepared first phosphor particles are weighed, dispersed in a solvent, and mixed with an inorganic binder to produce a phosphor ink for printing. At this time, the addition ratio of solvent and inorganic binder is adjusted to 46-60% in order to make the viscosity of the phosphor ink between 10 dPa·s and less than 35 dPa·s. A ball mill or propeller agitator can be used for mixing. The mixing time is adjusted to 80-160 minutes. During mixing, in order to suppress viscosity variations due to temperature changes, the room temperature is adjusted to 20°C-25°C and the liquid temperature to 25°C-40°C. High-boiling point solvents such as α-terpineol, butanol, isophorone, and glycerin can be used as solvents.

[0057] By adjusting the viscosity of the phosphor ink to between 10 dPa·s and less than 35 dPa·s, the flow of the phosphor ink causes the relatively large or heavy first phosphor particles to be biased towards the substrate side. Subsequently, drying and heat treatment can be performed to make a larger proportion of the first phosphor particles constituting the phosphor layer, those with a particle size equal to or greater than the average particle size, present on the substrate side. This improves the luminescence efficiency and the heat dissipation of the phosphor layer.

[0058] If the viscosity of the phosphor ink is less than 35 dPa·s, bleeding is likely to occur at the edges (outer periphery) of the phosphor layer due to the flow of the phosphor ink. Furthermore, it may become difficult to ensure sufficient thickness of the phosphor layer. When bleeding occurs, there is a risk of deterioration in the distribution of phosphor particles and a reduction in luminescence properties due to localized thinning of the film thickness. Therefore, it is preferable to apply phosphor ink with a viscosity of less than 35 dPa·s multiple times until the desired thickness is achieved. This suppresses bleeding at the edges of the phosphor layer and ensures sufficient thickness of the phosphor layer.

[0059] If the viscosity of the phosphor ink is less than 10 dPa·s, the fluidity of the phosphor ink may become too high, making it difficult to form the phosphor layer itself. Conversely, if the viscosity of the phosphor ink is 35 dPa·s or higher, the time required to declinate the first phosphor particles increases, leading to decreased production efficiency or preventing declination of the first phosphor particles altogether. Therefore, the viscosity of the phosphor ink should be adjusted to between 10 dPa·s and 35 dPa·s.

[0060] Inorganic fine particles may be added to the phosphorescent ink to improve the hardness of the phosphor layer and to adjust its luminescence (light scattering) and other properties. Inorganic fine particles may also be added to adjust the viscosity of the phosphorescent ink.

[0061] Next, a phosphorescent ink is applied to the surface of the substrate prepared in the substrate preparation step (step S1) to form an ink layer (paste layer) (step S3). The phosphorescent ink can be applied using screen printing, spraying, dispensing, or inkjet methods. Screen printing is preferred because it allows for the stable formation of an ink layer of uniform thickness. The thickness of the ink layer is adjusted so that it becomes a predetermined average film thickness after firing. It is preferable that the ink layer is formed along the shape of the substrate.

[0062] Then, the applied phosphor ink is heat-treated at a temperature of 150°C or higher to form a phosphor layer (Step S4). The heat treatment temperature is preferably 150°C to 500°C, and particularly preferably 300°C to 400°C. The heat treatment time is preferably set with a holding time of 20 minutes or more, and preferably 0.5 hours to 2.0 hours. The heating rate is preferably 2°C / min or higher, and more preferably 2°C / min to 10°C / min. A drying step may also be provided before the heat treatment. The drying temperature is preferably 100°C to 200°C (below the heat treatment temperature of the phosphor layer), and the drying time is more preferably 20 minutes to 60 minutes.

[0063] In this way, by adjusting the viscosity of the phosphor ink to a predetermined range and printing and heat-treating it on a substrate, it is possible to create a bias in the average particle size of phosphor particles within a single-layer phosphor layer, thereby enabling the manufacture of a wavelength conversion component with excellent heat dissipation and luminescence properties.

[0064] Figure 7 is a flowchart showing a modified example of a method for manufacturing a wavelength conversion member according to an embodiment of the present invention. The process from processing the raw materials to preparing the substrate (step T1) and then to applying the first phosphor ink (step T3) is the same as described above and is therefore omitted. The first phosphor ink is the phosphor ink described above.

[0065] Next, the first phosphor ink is dried (step T4). This allows the second phosphor layer to be laminated on top of the single-layer first phosphor layer, suppressing bleeding and pinholes around the edges of the phosphor layer and preventing color unevenness. It also allows each phosphor layer to have different properties. The drying temperature is preferably 100°C to 200°C (below the heat treatment temperature of the subsequent phosphor layer), and the drying time is more preferably 20 minutes to 60 minutes.

[0066] Next, the second phosphor particles and the second inorganic binder are mixed to produce a second phosphor ink (second phosphor paste) (step T5). To produce the second phosphor ink, first, second phosphor particles having a predetermined average particle size are prepared. Various types of second phosphor particles can be used depending on the design of the wavelength conversion member. The average particle size and type of the second phosphor particles may be the same as or different from those of the first phosphor particles. The second inorganic binder is preferably of the same type as the first inorganic binder, but may be of a different type. One or more types of phosphor particles other than the second phosphor particles may also be used.

[0067] Next, the prepared second phosphor particles are weighed, dispersed in a solvent, and mixed with a second inorganic binder to produce a phosphor ink for printing. When the viscosity of the second phosphor ink is to be between 10 dPa·s and less than 35 dPa·s, the addition ratio of the solvent and the second inorganic binder is adjusted to 46-60%. When the viscosity of the second phosphor ink is to be between 35 dPa·s and 75 dPa·s, the addition ratio of the solvent and the second inorganic binder is adjusted to 15-45%. A ball mill or propeller agitator can be used for mixing. The mixing time is adjusted to 80-160 minutes. During mixing, to suppress viscosity variations due to temperature changes, the room temperature is adjusted to 20-25°C and the liquid temperature to 25-40°C. High-boiling point solvents such as α-terpineol, butanol, isophorone, and glycerin can be used.

[0068] Inorganic fine particles may be added to the second phosphor ink for the purpose of improving the hardness of the second phosphor layer and adjusting its luminescence (light scattering properties). Inorganic fine particles may also be added to adjust the viscosity of the second phosphor ink.

[0069] Next, the second phosphor ink is applied to the surface (the surface facing the main surface) of the dried first phosphor ink produced in the drying process (step T4) to form a second ink layer (second paste layer) (step T6). The second phosphor ink can be applied using screen printing, spraying, dispensing, or inkjet methods. Screen printing is preferred because it allows for the stable formation of a second ink layer with uniform thickness. The thickness of the second ink layer is adjusted so that it reaches a predetermined average film thickness after firing. It is preferable that the second ink layer is formed along the shape of the first ink layer.

[0070] Furthermore, if the viscosity of the second phosphor ink exceeds 75.0 dPs, and the application method is screen printing, mesh marks may remain as traces on the phosphor layer, potentially causing cracking and peeling of the phosphor layer. In addition, poor fluidity of the phosphor ink increases the risk of voids (pinholes) forming, resulting in uneven luminescence and causing color inconsistencies.

[0071] Then, the applied first phosphor ink and second phosphor ink are heat-treated at a temperature of 150°C or higher to form the first phosphor layer and the second phosphor layer (Step S7). The heat treatment temperature is preferably 150°C or higher and 500°C or lower, and particularly preferably 300°C or higher and 400°C or lower. The heat treatment time is preferably set to a holding time of 20 minutes or more, and preferably 0.5 hours or higher and 2.0 hours or lower. The heating rate is preferably 2°C / min or higher, and more preferably 2°C / min or higher and 10°C / min or lower. In addition, a step of drying the second phosphor ink before heat treatment may be included. The drying temperature is preferably 100°C or higher and 200°C or lower (less than the heat treatment temperature of the phosphor layer), and the drying time is more preferably 20 minutes or higher and 60 minutes or lower.

[0072] In this way, by adjusting the viscosity of the first phosphor ink to a predetermined range, printing it on a substrate, drying it, and then printing the second phosphor ink onto the first ink layer and heat-treating it, a second phosphor layer can be laminated on top of a single-layer first phosphor layer that has an uneven distribution of the average particle size of the phosphor particles, thereby enabling the manufacture of a wavelength conversion member with excellent heat dissipation and luminescence properties.

[0073] [Examples and Comparative Examples] (Fabrication of wavelength conversion components) (Example 1-1) A disc-shaped sapphire substrate with a diameter of φ50 mm and a thickness of t0.5 mm was prepared as the base material. A yellow phosphor (YAG-based phosphor) with an average particle size of 15 μm, ethyl silicate as an inorganic binder, and α-terpineol as a solvent were weighed and mixed for 120 minutes using propeller stirring while maintaining the liquid temperature at 25°C to 40°C to prepare the first phosphor ink. At this time, the viscosity of the prepared first phosphor ink was measured using a viscometer (Viscotester VT-04F), and the amount of inorganic binder to be added was determined and added so that the viscosity of the first phosphor ink became 10 dPa·s.

[0074] The first phosphor ink obtained was applied to a substrate by screen printing so that the average film thickness of the phosphor layer after heat treatment was 50 μm. After drying the coated substrate at 100°C for 30 minutes, the wavelength conversion member of Example 1-1 was fabricated by heat treatment in an electric furnace in a non-oxidizing atmosphere at a rate of 150°C / h to 350°C and for 20 minutes.

[0075] (Examples 1-2) The wavelength conversion member of Example 1-2 was fabricated under the same conditions as in Example 1-1, except that the amount of inorganic binder added to the first phosphor ink was adjusted so that the viscosity was 20 dPa·s.

[0076] (Examples 1-3) The wavelength conversion member of Example 1-3 was fabricated under the same conditions as in Example 1-1, except that the amount of inorganic binder added to the first phosphor ink was adjusted so that the viscosity was 30 dPa·s.

[0077] (Example 2-1) A first phosphor ink and a second phosphor ink with a viscosity of 10 dPa·s were prepared under the same conditions as in Example 1-1. The first phosphor ink was applied to a substrate by screen printing so that the average film thickness of the first phosphor layer after heat treatment was 50 μm. The substrate was dried at 100°C for 30 minutes to form a phosphor layer precursor. Then, the second phosphor ink was applied to the phosphor layer precursor by screen printing so that the average film thickness of the second phosphor layer after heat treatment was 50 μm (total average film thickness of the phosphor layers was 100 μm). The substrate was then dried at 100°C for 30 minutes to form a second phosphor layer precursor. These phosphor layer precursors were heated in an electric furnace in a non-oxidizing atmosphere at 150°C / h to 350°C and heat-treated for 20 minutes to produce the wavelength conversion member of Example 2-1.

[0078] (Example 2-2) The wavelength conversion member of Example 2-2 was fabricated under the same conditions as in Example 2-1, except that the amount of inorganic binder added to the first and second phosphor inks was adjusted so that their respective viscosities were 20 dPa·s.

[0079] (Examples 2-3) The wavelength conversion member of Example 2-3 was fabricated under the same conditions as in Example 2-1, except that the amount of inorganic binder added to the first and second phosphor inks was adjusted so that their respective viscosities were 30 dPa·s.

[0080] (Example 3-1) The wavelength conversion member of Example 3-1 was fabricated under the same conditions as in Example 2-1, except that the amount of inorganic binder added to the second phosphor ink was adjusted so that the viscosity was 50 dPa·s.

[0081] (Example 3-2) The wavelength conversion member of Example 3-2 was fabricated under the same conditions as in Example 2-1, except that the amount of inorganic binder added to the first phosphor ink was adjusted so that the viscosity was 20 dPa·s, and the amount of inorganic binder added to the second phosphor ink was adjusted so that the viscosity was 60 dPa·s.

[0082] (Example 3-3) The wavelength conversion member of Example 3-3 was fabricated under the same conditions as in Example 2-1, except that the amount of inorganic binder added to the first phosphor ink was adjusted so that the viscosity was 30 dPa·s, and the amount of inorganic binder added to the second phosphor ink was adjusted so that the viscosity was 70 dPa·s.

[0083] (Comparative Example 1) A wavelength conversion component for Comparative Example 1 was prepared under the same conditions as in Example 1-1, except that the amount of inorganic binder added to the first phosphor ink was adjusted so that the viscosity was 60 dPa·s.

[0084] (Comparative Example 2) A wavelength conversion member for Comparative Example 2 was fabricated under the same conditions as in Example 1-1, except that the amount of inorganic binder added to the first phosphor ink was adjusted so that the viscosity was 60 dPa·s, and the first phosphor ink was applied to the substrate by screen printing so that the average film thickness of the phosphor layer after heat treatment was 100 μm.

[0085] (Evaluation method) (Luminous intensity test) For each wavelength conversion component, the emission intensity was confirmed by irradiating it with blue LD light with a wavelength of 450 nm using a laser beam with a laser output of 1.0 W. At this time, the emission intensity was set to 100, and the relative value was used.

[0086] (Luminescence uniformity test) For each wavelength conversion component, a 1.0W blue LD light with a wavelength of 450 nm was shone onto nine points (eight points at equal intervals circumferentially from the substrate side, plus the center point), and the illuminance (lx) of the synchrotron radiation was measured with an illuminometer. The average value and the deviation from each measurement point were calculated, and the uniformity of the emission intensity (emission variation) was confirmed by dividing the maximum (or minimum) deviation by the average value. A smaller value indicates less emission variation.

[0087] (Surface temperature measurement) For each wavelength conversion component, a 450 nm blue LD laser beam with a laser output of 1.0 W was irradiated onto the component from the substrate side for 10 minutes. The surface temperature of the phosphor layer was measured using an infrared thermography camera. The measurement was performed by recording the surface temperature of the phosphor layer immediately after 10 minutes of irradiation as the maximum temperature, and then checking the surface temperature of the phosphor layer 1 minute after stopping the laser irradiation.

[0088] (Cross-sectional observation using SEM) Cross-sectional SEM images of each sample were taken at 1000x magnification, and the cross-sectional area of ​​particles recognized as phosphor particles in each phosphor layer within the field of view was calculated. The average particle diameter D1 or D3 was determined from its cumulative distribution. In addition, the average particle diameter D2 or D4 was determined for the portion of each phosphor layer that is 1 / 3 of its thickness relative to the average film thickness (substrate side region or phosphor layer side region). The relationship between these values ​​was then examined.

[0089] Figure 8 is a table showing the manufacturing conditions and evaluation test results for the wavelength conversion members of the examples and comparative examples. The viscosity (dPa·s) of the phosphor layer and the second phosphor layer in Figure 8 indicates the viscosity of the phosphor ink used to form the phosphor layer or the second phosphor layer at 25°C. The average film thickness (μm) indicates the average film thickness of the phosphor layer or the second phosphor layer as determined by cross-sectional observation by SEM after manufacturing. The average particle size D1 (μm) or average particle size D3 (μm) indicates the average particle size D1 of the first phosphor particles in the phosphor layer or the average particle size D3 of the second phosphor particles in the second phosphor layer as determined by cross-sectional observation by SEM after manufacturing. Hereafter, Examples ○-1 to ○-3 will be collectively referred to as Example ○ (○ represents 1 to 3).

[0090] In Examples 2 and 3, where a bias was created in the average particle size of the phosphor particles in the phosphor layer formed on the surface of the substrate, and a second phosphor layer was formed on top of it, the luminescence intensity was 98.0 or higher, which can be evaluated as excellent luminescence intensity. This is presumed to be because phosphor particles with a large particle size, which have excellent luminescence efficiency, were distributed in large numbers on the substrate side, which is the light source irradiation side. Furthermore, Example 1, which had the thinnest average film thickness of the phosphor layer, showed the best luminescence intensity. On the other hand, the luminescence intensity of Comparative Examples 1 and 2, in which the distribution of phosphor particles in the phosphor layer was relatively uniform, was slightly lower than that of Examples 1 to 3.

[0091] Examples 3, Comparative Examples 1 and 2, in which a phosphor layer with a uniform distribution of phosphor particles was formed on the side irradiated by wavelength-converted light, showed the smallest variation in illuminance. Example 2 showed the next smallest variation in illuminance. This is presumed to be because pinholes and blurring present in parts of the phosphor layer were mitigated by the lamination process.

[0092] Immediately after laser irradiation, the temperature of the phosphor layer was approximately 120°C in all test examples. Subsequently, one minute after stopping laser irradiation, the temperature of the phosphor layer was lowest in Example 1 and highest in Comparative Example 2. This is likely because, compared to Example 1, the phosphor layer of Comparative Example 2 had a higher distribution of small-particle phosphors on the substrate side, resulting in more binder interposed between the particles and thus poor thermal conductivity to the substrate. On the other hand, the phosphor layer of Example 1 had a higher distribution of large-particle phosphors, resulting in less binder interposition and good thermal conductivity of the phosphors themselves, which likely contributed to better heat dissipation. A similar relationship was observed between Example 1 and Comparative Example 1, which were compared with almost identical average film thicknesses.

[0093] In the wavelength conversion members of Examples 1 to 3, the D2 / D1 value was 1.1 or higher, confirming the presence of relatively large-particle-sized phosphor particles on the substrate side. This is expected to improve not only heat dissipation but also luminous efficiency. In Example 2, the D4 / D3 value was also 1.1 or higher. In Example 3, the D4 / D3 value was 0.9 or higher.

[0094] From the above results, it was found that the wavelength conversion member of the present invention exhibits excellent luminescence intensity and heat dissipation. This makes it possible to suppress performance degradation as the output of the light-emitting element is increased. Furthermore, by using a laminated structure, variations in luminescence intensity can be reduced.

[0095] The present invention is not limited to the embodiments described above, and it goes without saying that it extends to various modifications and equivalents that fall within the spirit and scope of the present invention. Furthermore, the structure, shape, number, position, size, etc., of the components shown in each drawing are for illustrative purposes only and may be modified as appropriate. [Explanation of symbols]

[0096] 10 Base material 12 Main surface 20 Phosphor layer 22 First phosphor particle 24 Translucent Ceramics 26 Base material side area 28 Surface facing the main surface of the substrate 30 Second phosphor layer 32. Second phosphor particle 34. Second type of translucent ceramics 36 Phosphor layer side region 38 Surface of the second phosphor layer 40 void 100 wavelength conversion component 150 light source 200 Light-emitting devices

Claims

1. A wavelength conversion member, A light-transmitting substrate, The substrate comprises a single-layer phosphor layer provided on one main surface of the substrate, which includes at least first phosphor particles and translucent ceramics that bond the first phosphor particles to each other and to the substrate and to the first phosphor particles. The average particle size D1 of the first phosphor particles in the phosphor layer is 5 μm or more and 30 μm or less. The phosphor layer is such that the average particle diameter D2 of the first phosphor particles in the substrate-side region of the average thickness of the phosphor layer perpendicular to the main surface, which is 1 / 3 of the total thickness on the substrate side, is larger than the average particle diameter D1. The present invention further comprises a single-layer second phosphor layer, which is provided on the surface of the phosphor layer facing the main surface and includes at least second phosphor particles that are of the same type as or different type as the first phosphor particles, and a second translucent ceramic that binds the second phosphor particles to each other and to the phosphor layer and to the second phosphor particles, A wavelength conversion member characterized in that the average particle diameter D3 of the second phosphor particles in the second phosphor layer is 5 μm or more and 30 μm or less.

2. A wavelength conversion member, A light-transmitting substrate, The substrate comprises a single-layer phosphor layer provided on one main surface of the substrate, which includes at least first phosphor particles and translucent ceramics that bond the first phosphor particles to each other and to the substrate and to the first phosphor particles. The average particle size D1 of the first phosphor particles in the phosphor layer is greater than 20 μm and 30 μm or less. The wavelength conversion member is characterized in that the phosphor layer has an average particle diameter D2 of the first phosphor particles in the substrate-side region of the average thickness of the phosphor layer perpendicular to the main surface, which is 1 / 3 of the average thickness of the phosphor layer on the substrate side, and is larger than the average particle diameter D1.

3. The present invention further comprises a single-layer second phosphor layer, which is provided on the surface of the phosphor layer facing the main surface and includes at least second phosphor particles that are of the same type as or different type as the first phosphor particles, and a second translucent ceramic that binds the second phosphor particles to each other and to the phosphor layer and to the second phosphor particles, The wavelength conversion member according to claim 2, characterized in that the average particle diameter D3 of the second phosphor particles in the second phosphor layer is greater than 20 μm and 30 μm or less.

4. The wavelength conversion member according to claim 1 or 3, characterized in that the second phosphor layer has an average particle diameter D4 of the second phosphor particles in the phosphor layer-side region of the average thickness of the second phosphor layer perpendicular to the main surface that is greater than the average particle diameter D3.

5. A light-emitting device, A light-emitting element that emits light within a specific range of wavelengths, A light-emitting device comprising a wavelength conversion member according to any one of claims 1 to 3.

Images