Wavelength conversion member, phosphor device, and method for producing wavelength conversion member

Abstract

A wavelength conversion member (1) comprises: a phosphor substrate (10) that has a plurality of pores (11); an embedding layer (30) that is provided higher than the phosphor substrate (10) and that fills the plurality of pores (11) which are exposed on the phosphor substrate (10); and a light-reflecting layer (50) that is provided higher than the embedding layer (30), wherein in plan view of the phosphor substrate (10), the embedding layer (30) has a region (31) that does not overlap with the light-reflecting layer (50).

Description

Wavelength conversion member, phosphor device, and method for manufacturing wavelength conversion member

[0001] The present invention relates to a wavelength conversion member, a phosphor device, and a method for manufacturing a wavelength conversion member.

[0002] Light source modules using solid-state light-emitting elements such as LEDs or semiconductor lasers as light sources are used in projectors, endoscopes, vehicle headlamps, lighting devices, liquid crystal display devices, etc. This type of light source module includes, for example, a light source and a phosphor device that emits fluorescence when light emitted by the light source is incident thereon.

[0003] The phosphor device includes, for example, a substrate and a wavelength conversion member provided on the substrate. Patent Document 1 discloses a phosphor device including a substrate, a wavelength conversion member, and a bonding material that bonds the substrate and the wavelength conversion member, and the wavelength conversion member includes a phosphor layer (phosphor substrate), a reflective member (light-reflecting layer), and a bonding auxiliary layer that assists bonding by the bonding material.

[0004] Japanese Patent Application Laid-Open No. 2019-105763

[0005] The phosphor substrate disclosed in Patent Document 1 has pores, which may be exposed on the surface of the phosphor substrate. When a light-reflecting layer is formed on this surface, the unevenness caused by the pores cannot be sufficiently filled, resulting in phenomena such as the light-reflecting layer being interrupted. As a result, light reflection is insufficient, and the luminous efficiency of the wavelength conversion member is reduced.

[0006] Furthermore, in Patent Document 1, a bonding auxiliary layer made of a metal material is formed on the surface of the phosphor substrate. In the technology disclosed in Patent Document 1, the bonding auxiliary layer is prone to peeling. Such peeling reduces the reliability of the wavelength conversion member.

[0007] The present invention has been made in view of the above problems, and has an object to provide a wavelength conversion member or the like having high luminous efficiency and reliability.

[0008] In order to achieve the above object, one aspect of the wavelength conversion member of the present invention comprises a phosphor substrate having a plurality of pores, a buried layer provided above the phosphor substrate and filling the plurality of pores exposed on the surface of the phosphor substrate, and a light-reflecting layer provided above the buried layer, wherein, in a planar view of the phosphor substrate, the buried layer has an area that does not overlap with the light-reflecting layer.

[0009] Furthermore, one aspect of the phosphor device according to the present invention comprises a phosphor substrate having a plurality of pores, a buried layer provided above the phosphor substrate and filling the plurality of pores exposed on the surface of the phosphor substrate, and a light-reflecting layer provided above the buried layer, wherein the thickness of the light-reflecting layer at the ends is thinner than the thickness of the light-reflecting layer at the center.

[0010] Moreover, one aspect of a phosphor device according to the present invention includes the wavelength conversion member described above and a support substrate that supports the wavelength conversion member.

[0011] Furthermore, one aspect of the method for manufacturing a wavelength conversion member according to the present invention includes a first step of preparing a phosphor substrate having a plurality of pores, a second step of forming a buried layer above the phosphor substrate by a wet process so as to fill the plurality of pores exposed on the surface of the phosphor substrate, and a third step of forming a light-reflecting layer above the buried layer, wherein, in a planar view of the phosphor substrate, the buried layer has an area that does not overlap with the light-reflecting layer.

[0012] According to the present invention, it is possible to provide a wavelength conversion member or the like having high luminous efficiency and reliability.

[0013] Fig. 1 is a diagram showing a configuration of a wavelength conversion member according to an embodiment. Fig. 2 is a diagram showing an example of use of a wavelength conversion member according to an embodiment. Fig. 3 is a diagram for explaining a method for manufacturing a wavelength conversion device according to an embodiment. Fig. 4 is a plan view of a bonded body according to an embodiment. Fig. 5 is a cross-sectional view showing a configuration of a wavelength conversion member according to a modified example of the embodiment.

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, component arrangements and connection forms, steps, and step sequences shown in the following embodiments are merely examples and are not intended to limit the present invention. Therefore, among the components in the following embodiments, components not recited in independent claims will be described as optional components.

[0015] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales of the figures do not necessarily match. Furthermore, in each figure, substantially the same components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0016] Furthermore, in this specification, terms indicating the relationship between elements, terms indicating the shape of elements such as circle or rectangle, and numerical ranges are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about a few percent.

[0017] In addition, in this specification, the terms "upper" and "lower" do not refer to the upper direction (vertically upper) and lower direction (vertically lower) in absolute spatial recognition, but are used as terms defined by a relative positional relationship based on the stacking order in the stacking configuration. In the following description, the direction in which the phosphor layer is located relative to the substrate is considered to be "upper," and the opposite side is considered to be "lower." Furthermore, the terms "upper" and "lower" apply not only to cases in which two components are arranged with a gap between them and another component is present between them, but also to cases in which two components are arranged closely together and the two components are in contact with each other.

[0018] (Embodiment) [Configuration] First, the configuration of a wavelength conversion member 1 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing the configuration of a wavelength conversion member 1 according to this embodiment. Fig. 1(a) is a plan view of the wavelength conversion member 1, and Fig. 1(b) is a cross-sectional view of the wavelength conversion member 1 taken along line bb in Fig. 1(a).

[0019] As shown in Fig. 1 , the wavelength conversion member 1 includes a phosphor substrate 10, an embedding layer 30, a bonding layer 40, a light reflecting layer 50, and a bonding auxiliary layer 60. The plan view shown in Fig. 1 (a) is a plan view of the phosphor substrate 10.

[0020] The phosphor substrate 10 is a phosphor section made of a phosphor that emits fluorescence when light is incident thereon. Specifically, the phosphor substrate 10 is excited by excitation light and emits fluorescence with a wavelength longer than that of the excitation light. As an example, the phosphor substrate 10 is made of a yellow phosphor. In this case, the phosphor substrate 10 made of a yellow phosphor emits yellow fluorescence using light with a shorter wavelength than yellow light (e.g., ultraviolet light to blue light) as excitation light. In other words, the phosphor substrate 10 made of a yellow phosphor converts the wavelength of the excitation light to yellow light with a longer wavelength than that of the excitation light. Note that the emission wavelength of the phosphor substrate 10 is not limited to wavelengths in the visible light band, but may be a wavelength in the infrared light range. In this case, the phosphor substrate 10 includes a phosphor that emits light with a wavelength in the infrared light range.

[0021] The phosphor substrate 10 is a phosphor portion made only of phosphor. In this embodiment, the phosphor substrate 10 is a phosphor plate made of phosphor ceramics. That is, the main component of the phosphor substrate 10 is phosphor ceramics. As an example, the phosphor substrate 10 is made of phosphor ceramics made of sintered polycrystalline phosphor. In this embodiment, the phosphor substrate 10 is made of phosphor ceramics only. That is, the phosphor substrate 10 does not contain a binder.

[0022] In this way, by making the phosphor substrate 10 only from phosphor ceramics, it is possible to improve the heat resistance and thermal conductivity of the phosphor substrate 10. Furthermore, in the case of a phosphor substrate made of phosphor particles and a binder such as silicone, the binder deteriorates, increasing non-luminescent absorption and reducing the conversion efficiency of the phosphor substrate, which converts excitation light into fluorescence. However, by making the phosphor substrate 10 only from phosphor ceramics, it is possible to maintain the conversion efficiency of the phosphor substrate 10 for a long period of time.

[0023] Furthermore, examples of phosphors that constitute phosphor ceramics include YAG (yttrium aluminum garnet) YAG. ３ Al ５ O １２ ), LuAG (Lutetium Aluminum Garnet) Lu ３ Al ５ O １２ ), Lu ２ CaMg ２ Si ３ O １２ (Lutetium Calcium Magnesium Silicon Garnet) and TAG (Terbium Aluminum Garnet), Gd ３ Ga ５ O １２ , (Ga ０．６ Sc ０．４ ) ２ O ３ YAG, LuAG, Lu ２ CaMg ２ Si ３ O １２ The dopant to be doped into the phosphor such as TAG can be appropriately selected from Ce, Eu, Cr, and the like.

[0024] In this embodiment, the phosphor substrate 10 is made of only phosphor ceramics consisting of sintered YAG doped with Ce. ３＋ It is made of YAG phosphor ceramics (refractive index 1.9) containing ZnO, and emits yellow fluorescence.

[0025] In this embodiment, from the viewpoint of conversion efficiency and temperature characteristics, a Ce-doped YAG single-phase polycrystalline body is used for the phosphor substrate 10, but other materials may be mixed in as long as they do not change in quality in air at 300° C. For example, the object of the present invention can be achieved even if the phosphor substrate 10 contains a few percent of YAP, yttria, alumina, or the like.

[0026] The density of the phosphor substrate 10 is preferably 95% or more but less than 100% of the theoretical density of the phosphor (phosphor ceramic) constituting the phosphor substrate 10. Here, the theoretical density refers to the density when atoms in the phosphor layer are ideally arranged. The theoretical density refers to the density when it is assumed that the phosphor substrate 10 does not have pores 11 (voids), and is a value calculated using the crystal structure. For example, if the density of the phosphor substrate 10 is 99%, the remaining 1% corresponds to the pores 11. In other words, the higher the density of the phosphor substrate 10, the fewer the pores 11. When the density of the phosphor substrate 10 is within the above range, the total amount of fluorescence emitted by the phosphor substrate 10 increases, thereby realizing a wavelength conversion member 1 that emits a greater amount of light. In this embodiment, since the phosphor substrate 10 has a plurality of pores 11, the density of the phosphor substrate 10 is less than 100% of the theoretical density. Furthermore, the phosphor ceramic according to this embodiment has a theoretical density of 4.56 g / cm. ３ Since the phosphor substrate 10 is YAG, the density of the phosphor substrate 10 is 4.32 g / cm ３ 4.56g / cm or more ３ is less than.

[0027] The phosphor substrate 10 has a first surface 10a and a second surface 10b opposite to the first surface 10a. The first surface 10a is the upper surface of the phosphor substrate 10, and the second surface 10b is the lower surface of the phosphor substrate 10. The first surface 10a is the surface on the buried layer 30 side. On the other hand, the second surface 10b is an exposed surface exposed to the atmosphere.

[0028] The phosphor substrate 10 has a rectangular flat plate shape with a constant thickness. Therefore, the first surface 10a and the second surface 10b of the phosphor substrate 10 have a rectangular shape in a plan view. However, the plan view shapes of the first surface 10a and the second surface 10b are not limited to a rectangular shape.

[0029] As described above, a plurality of pores 11 are provided in the phosphor substrate 10. The presence of the plurality of pores 11 allows the excitation light incident on the phosphor substrate 10 and the generated fluorescence to be scattered. Furthermore, some of the plurality of pores 11 are present in the phosphor substrate 10, and other portions of the plurality of pores 11 are present on the surface of the phosphor substrate 10 (e.g., the first surface 10a or the second surface 10b). In other words, other portions of the plurality of pores 11 are exposed on the surface of the phosphor substrate 10. The shape of the pores 11 is polyhedral, but this is not limited thereto and other shapes may also be used. For example, the shape of the pores 11 is irregular and is not limited to a polyhedral shape. As described above, by providing a plurality of pores 11 in the phosphor substrate 10, the excitation light and the generated fluorescence are scattered by the pores 11 within the phosphor substrate 10, thereby suppressing waveguiding of the fluorescence within the phosphor substrate 10. Since the waveguiding of fluorescence can be suppressed, the fluorescence size (emission spot diameter) can be made closer to the size of the excitation light (received light spot diameter) on the second surface 10b of the phosphor substrate 10 where the light (excitation light) from the light source is incident, making it possible to realize a fluorescent light source with high brightness.

[0030] The thickness of the flat phosphor substrate 10 is on the order of microns, less than 500 μm. In this embodiment, the thickness of the phosphor substrate 10 is 100 μm or less. In the phosphor substrate 10, the second surface 10b of the phosphor substrate 10, on which light from the light source is incident, absorbs more excitation light than the first surface 10a, so the temperature of the second surface 10b is higher than that of the first surface 10a. Therefore, in order to lower the temperature of the phosphor substrate 10, it is preferable to shorten the distance from the second surface 10b of the phosphor substrate 10, on which light from the light source is incident, to the first surface 10a. In particular, since pores 11 are provided to suppress waveguiding of fluorescence within the phosphor substrate 10, the thermal conductivity of the phosphor substrate 10 is poorer than that of a phosphor substrate without pores 11. Therefore, it is preferable that the thickness of the phosphor substrate 10 be 80 μm or less. On the other hand, considering the volume required for the light incident on the phosphor substrate 10 to be absorbed by the phosphor ceramic and for the phosphor substrate 10 to emit light efficiently, the thickness of the phosphor substrate 10 should be 30 μm or more.

[0031] The embedding layer 30 is a layer provided above the phosphor substrate 10. That is, the embedding layer 30 is formed on the first surface 10a of the phosphor substrate 10. As described above, the pores 11 may be exposed on the first surface 10a of the phosphor substrate 10. Therefore, when a reflective layer such as the light-reflecting layer 50 is formed on the phosphor substrate 10, if the reflective layer is thin relative to the size of the pores 11, it will be interrupted at the pores 11, resulting in a decrease in reflectivity. In particular, when a dielectric multilayer film is used as the reflective layer, the decrease in reflectivity becomes significant. For this reason, it is advisable to form the embedding layer 30 before forming the reflective layer to flatten the surface on which the reflective layer will be formed.

[0032] The burying layer 30 is preferably made of a dielectric material that transmits the excitation light incident on the phosphor substrate 10 and the emitted fluorescence. In this embodiment, the burying layer 30 is made of silicon dioxide (SiO ２ The buried layer 30 is a dielectric film such as a silicon oxide film made of a material selected from the group consisting of silicon dioxide, silicon dioxide, and silicon dioxide. The buried layer 30 can be formed by a wet process. For example, the buried layer 30 can be formed by applying a liquid material to the first surface 10a of the phosphor substrate 10, spreading it by spin coating, and solidifying it. This allows the buried layer 30 to have a smooth, flat surface.

[0033] The method for forming the buried layer 30 is not limited to a wet process, but may also be a dry process. For example, the buried layer 30 may be formed on the first surface 10a of the phosphor substrate 10 by a vapor deposition method, a chemical vapor deposition (CVD) method, or a sputtering method such as a plasma-balanced system (PLABAS). Furthermore, after forming the buried layer 30, the surface of the buried layer 30 may be polished to make it a smooth plane.

[0034] When the thickness of the buried layer 30 is C and the average size of the plurality of pores 11 is D, C and D satisfy the following formula.

[0035] D / 3≦C≦3×D

[0036] The size of the pores 11 refers to the distance from one end to the other end of the pores 11 in the longitudinal direction as shown in an optical microscope image obtained when observing the interior of the phosphor substrate 10 (between the first surface 10a and the second surface 10b) with an optical microscope. The average size (D) of the pores 11 is an arithmetic mean. FIG. 1 also shows the thickness (C) of the buried layer 30; that is, the thickness (C) of the buried layer 30 is the distance between the flat portion of the first surface 10a that does not contain pores and the upper surface of the buried layer 30. The thickness (C) of the buried layer 30 is measured by cross-sectional electron microscope observation.

[0037] When C and D satisfy D / 3≦C, the embedding layer 30 can substantially embed the pores 11. Therefore, it is possible to form an embedding layer 30 having a substantially smooth flat surface. Furthermore, C and D satisfy C≦3×D. If C is a value greater than this, the thermal conductivity of the embedding layer 30 will be significantly reduced, and the temperature of the phosphor substrate 10 will rise to an unusable level during use.

[0038] That is, when C and D satisfy the above formula, it is possible to form the embedded layer 30 having a smooth, flat surface and to sufficiently dissipate heat from the phosphor substrate 10. Note that C and D may satisfy D≦C≦2×D or 1.2D≦C≦1.5×D.

[0039] The average size (D) of the pores 11 is set to be in the range of 200 nm or more and 3 μm or less. As described above, in order to realize a fluorescent light source with high brightness, the average size (D) of the pores 11 should be in the range of 300 nm or more and 2 μm or less. Therefore, when the average size (D) of the pores 11 is 0.9 μm, for example, the thickness (C) of the buried layer 30 should be in the range of 300 nm or more and 2.7 μm or less. The buried layer 30 is made of silicon dioxide (SiO ２ The thickness (C) of the buried layer 30 is not limited to the above, but may be any dielectric material that does not absorb excitation light and fluorescence, such as titanium oxide, niobium oxide, or tantalum oxide, and may be a multi-layer dielectric material. When the buried layer 30 has multiple layers, the thickness (C) refers to the total thickness of all the layers.

[0040] Then, the bonding layer 40 is provided on the smooth flat surface (upper surface) of the buried layer 30. As shown in Fig. 1, the bonding layer 40 is provided on most of the upper surface of the buried layer 30, but is not provided on the other part of the upper surface.

[0041] The bonding layer 40 is a layer provided above the embedding layer 30. In other words, the bonding layer 40 is formed on the surface of the embedding layer 30 opposite to the phosphor substrate 10. The bonding layer 40 is a layer for bonding the embedding layer 30 and the light reflecting layer 50 together.

[0042] The bonding layer 40 is preferably made of a dielectric material that transmits the excitation light incident on the phosphor substrate 10 and the emitted fluorescence. More specifically, the bonding layer 40 is preferably a dielectric film made of the same material as the embedding layer 30, and in this embodiment, silicon dioxide (SiO ２ The bonding layer 40 is a dielectric film such as a silicon oxide film made of the same material as the buried layer 30. By forming the bonding layer 40 from the same material as the buried layer 30, the adhesion between the bonding layer 40 and the buried layer 30 is increased, making the bonding layer 40 less likely to peel off from the buried layer 30. Therefore, when the buried layer 30 is made of titanium oxide, it is desirable that the bonding layer 40 is also made of titanium oxide. Furthermore, when the buried layer 30 is formed of multiple layers, it is desirable that the bonding layer 40 and the layer of the buried layer 30 that is in contact with the bonding layer 40 be made of the same material. The bonding layer 40 can be formed by a dry process such as evaporation or chemical vapor deposition.

[0043] The bonding layer 40 is provided on the smooth plane (upper surface) of the buried layer 30. Therefore, the upper surface of the bonding layer 40 is also smooth. Then, the light reflecting layer 50 is provided on the smooth plane (upper surface) of the bonding layer 40.

[0044] The light-reflecting layer 50 is a layer provided above the bonding layer 40, that is, it is formed on the surface of the bonding layer 40 opposite to the buried layer 30. The wavelength conversion member 1 in this embodiment is a reflective member that reflects light from a light source using the light-reflecting layer 50 and emits the emitted light toward the light source. Specifically, the light-reflecting layer 50 reflects light from the light source that is incident from the second surface 10b of the phosphor substrate 10 and fluorescence generated by the phosphor substrate 10 that passes through the buried layer 30 and the bonding layer 40 toward the first surface 10a.

[0045] The light-reflecting layer 50 is a metal film primarily composed of a metal such as silver. In this case, the metal-based light-reflecting layer 50 can be formed, for example, by vapor deposition. The light-reflecting layer 50 is not limited to a metal film. For example, the light-reflecting layer 50 may be a dielectric multilayer film. In this case, a dielectric multilayer film with a reflectance of 90% or more can be formed by stacking multiple dielectric films with different refractive indices. Furthermore, a composite film of a dielectric multilayer film and a metal film for the light-reflecting layer 50 is even better, since it can increase light reflectance over a wide angle with fewer layers and can be designed to achieve a more enhanced reflection effect than a metal film alone. In this case, the wavelength conversion member 1 has a layered structure of the phosphor substrate 10 / burying layer 30 / bonding layer 40 / dielectric multilayer film / metal film. For the dielectric multilayer film, silicon oxide can be used as the low-refractive index material, and tantalum oxide, titanium oxide, or niobium oxide can be used as the high-refractive index material. However, from the standpoint of light resistance and heat resistance, tantalum oxide is preferably used as the high-refractive index material. As the metal film, in addition to silver, APC (Ag-Pd-Cu alloy), Al, Pt, Rh, etc. can be used.

[0046] The light reflecting layer 50 may be manufactured continuously by the same method (process) as that used to manufacture the bonding layer 40, and may be formed by a dry process as described above. For example, when the bonding layer 40 and the light reflecting layer 50 are manufactured continuously by vapor deposition, the surface of the bonding layer 40 is not exposed to the atmosphere after the bonding layer 40 is manufactured and before the light reflecting layer 50 is manufactured. This makes it difficult for foreign matter (contaminants) to be mixed into the surface, improves adhesion between the bonding layer 40 and the light reflecting layer 50, and makes it difficult for the light reflecting layer 50 to peel off from the bonding layer 40.

[0047] The bonding auxiliary layer 60 is a layer provided above the light reflecting layer 50, that is, it is formed on the surface of the light reflecting layer 50 opposite to the bonding layer 40. Although not shown in Fig. 1 , a support substrate for supporting the wavelength conversion member 1 and a bonding material for bonding the support substrate and the wavelength conversion member 1 are further provided above the bonding auxiliary layer 60. The bonding auxiliary layer 60 is a layer that assists in bonding the support substrate and the wavelength conversion member 1 (more specifically, the light reflecting layer 50) with the bonding material.

[0048] The bonding auxiliary layer 60 is preferably made of a material that easily bonds to the bonding material. For example, if the bonding material is Ag, the bonding auxiliary layer 60 is preferably Ag or Au, and if the bonding material is a eutectic solder such as AuSn or SnAgCu, the bonding auxiliary layer 60 is preferably Au. The bonding auxiliary layer 60, which is a metal film, can be formed by, for example, a vapor deposition method.

[0049] Here, attention is focused on the shape of the wavelength conversion member 1 .

[0050] The side surfaces (side end surfaces) of the phosphor substrate 10 are substantially flush with the side surfaces (side end surfaces) of the burying layer 30. In this embodiment, the side surfaces of the phosphor substrate 10 and the burying layer 30 are substantially flush with each other over the entire periphery. In other words, the phosphor substrate 10 and the burying layer 30 have substantially the same shape and size in a plan view. Here, the planar shapes of the phosphor substrate 10 and the burying layer 30 are rectangular.

[0051] Furthermore, the side surfaces (side end faces) of the bonding layer 40, the side surfaces (side end faces) of the light reflecting layer 50, and the side surfaces (side end faces) of the bonding auxiliary layer 60 are all substantially flush with each other. In this embodiment, the side surfaces of the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60 are all substantially flush with each other over the entire periphery. In other words, the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60 have substantially the same shape and size in a planar view. Here, the shapes of the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60 in a planar view are rectangular.

[0052] Furthermore, in a planar view, the buried layer 30 has a region 31 that does not overlap with the light reflecting layer 50 (more specifically, the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60). That is, in a planar view, the buried layer 30 is larger than the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60. In the present embodiment, the buried layer 30 has a region 31 that surrounds the entire periphery of the light reflecting layer 50. The region 31 has a rectangular frame shape in a planar view, and the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60 are provided inside the frame shape. The region 31 can also be said to be a portion of the buried layer 30 that protrudes from the outer shape of the light reflecting layer 50 in a planar view, or a portion of the buried layer 30 that is not covered by the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60.

[0053] Next, a use example of the wavelength conversion member 1 according to the present embodiment will be described with reference to Fig. 2. Fig. 2 is a diagram showing a use example of the wavelength conversion member 1 according to the present embodiment. Fig. 2 shows the configuration of a phosphor device 3 including the wavelength conversion member 1. Furthermore, the phosphor module 4 shown in Fig. 2 is a module including a light source 2 and the phosphor device 3.

[0054] The support substrate 20 included in the phosphor device 3 is a rigid substrate that supports the wavelength conversion member 1 and has higher rigidity than the wavelength conversion member 1 (more specifically, the phosphor substrate 10).

[0055] Furthermore, the support substrate 20 not only functions to support the wavelength conversion member 1, but also to spread the heat generated in the phosphor substrate 10 of the wavelength conversion member 1 in the planar direction and efficiently conduct the heat to a heat dissipation member (not shown) such as a heat dissipation fin. In other words, the support substrate 20 also functions as a heat spreader substrate. Therefore, the support substrate 20 is preferably made of a material with high thermal conductivity. Specifically, the thermal conductivity of the support substrate 20 is preferably higher than that of the phosphor substrate 10. This allows the heat generated in the phosphor substrate 10 to be efficiently conducted to the support substrate 20. The thermal conductivity of the support substrate 20 is preferably 100 W / (m·K) or more.

[0056] Examples of the support substrate 20 include an aluminum substrate (Al substrate), a copper substrate (Cu substrate), a molybdenum substrate (Mo substrate), a tungsten substrate (W substrate), a silicon substrate (Si substrate), a silicon carbide substrate (SiC substrate), a silicon nitride substrate (SiN substrate), and an aluminum nitride substrate (AlN substrate). The silicon substrate or AlN substrate does not need to be single crystal and may be polycrystalline. The support substrate 20 may also be an alloy substrate made of multiple types of alloys. For example, the support substrate 20 may be a copper-tungsten composite substrate (Cu—W substrate), a copper-molybdenum substrate (Cu—Mo substrate), a copper-carbon composite substrate (Cu—C substrate), a magnesium silicon carbide substrate (Mg—SiC substrate), or the like.

[0057] The support substrate 20 is a flat plate with a substantially uniform thickness, and is rectangular in plan view. The thickness of the support substrate 20 is thicker than that of the phosphor substrate 10 and thinner than its width (length in the planar direction). The thickness of the support substrate 20 is 400 μm or more. Specifically, the thickness of the support substrate 20 is five times or more the thickness of the phosphor substrate 10. The thickness of the support substrate 20 may be 1 mm or more, and may be thicker, 3 mm or more, to spread heat in the planar direction and reduce thermal resistance with a heat dissipation member (not shown), such as a heat dissipation fin. The width of the support substrate 20 is approximately three to 20 times the width of the wavelength conversion member 1 (more specifically, the width of the phosphor substrate 10). The thickness of the support substrate 20 is thinner than the width of the support substrate 20, and is approximately equal to (one time) to three times the width of the wavelength conversion member 1, thereby enabling efficient heat conduction.

[0058] The support substrate 20 is provided above the wavelength conversion member 1 (more specifically, the bonding auxiliary layer 60 ), and the wavelength conversion member 1 and the support substrate 20 are fixed together by a bonding material 70 .

[0059] The bonding material 70 included in the phosphor device 3 is a material that bonds the wavelength conversion member 1 and the support substrate 20. In other words, the bonding material 70 exists as an adhesive layer between the wavelength conversion member 1 and the support substrate 20. As shown in FIG. 2 , the bonding material 70 may be present not only on the upper surface of the bonding auxiliary layer 60, but also on the side surfaces of the phosphor substrate 10, the embedding layer 30, the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60. This increases the thermal conductivity from the wavelength conversion member 1 to the support substrate 20 compared to when the bonding material 70 is bonded only to the bonding auxiliary layer 60.

[0060] The bonding material 70 may be made of a material with high thermal conductivity, such as a thermally conductive adhesive. Alternatively, the bonding material 70 may be a metal paste using Cu or Ag, a resin containing a highly thermally conductive filler, or solder.

[0061] The wavelength conversion member 1, phosphor device 3, and phosphor module 4 configured in this manner can be used in a variety of products such as projectors, endoscopes, vehicle headlamps, lighting devices, and liquid crystal display devices.

[0062] Next, the behavior of the light L1 from the light source 2 in FIG. 2 will be described.

[0063] FIG. 2 shows how light L1 from the light source 2 is incident on the wavelength conversion member 1 and how output light L3 is emitted from the wavelength conversion member 1 (phosphor device 3).

[0064] 2 , light L1 emitted from a light source 2 is incident on the wavelength conversion member 1. Specifically, light L1 emitted from the light source 2 is incident on a phosphor substrate 10 of the wavelength conversion member 1. The light source 2 is, for example, a laser light source having a semiconductor laser that emits laser light as light L1. Therefore, the phosphor substrate 10 of the wavelength conversion member 1 is irradiated with the laser light.

[0065] Light L1 emitted from the light source 2 is incident on the phosphor substrate 10 of the wavelength conversion member 1 as excitation light. As a result, the phosphor substrate 10 is excited by the light L1 from the light source 2, and fluorescence of a predetermined color is generated in the phosphor substrate 10. That is, part of the light L1 (excitation light) from the light source 2 is wavelength-converted in the phosphor substrate 10 to become light L2 (fluorescence) of a predetermined wavelength. Then, light L2, which is the fluorescence generated in the phosphor substrate 10, is mixed with another part of the light L1 from the light source 2 that is light L1 from the light source 2 that has been incident on the phosphor substrate 10 and has not been wavelength-converted, and this mixed light is emitted from the phosphor substrate 10 as emitted light L3.

[0066] In this embodiment, since the wavelength conversion member 1 is provided with the light-reflecting layer 50, the wavelength conversion member 1 is a reflective phosphor member that reflects light L1 from the light source 2 and emits output light L3 toward the light source 2. Specifically, light L2 (fluorescence) generated by the phosphor substrate 10 and light L1 (excitation light) from the light source 2 that is incident on the phosphor substrate 10 and has not been wavelength-converted by the phosphor substrate 10 are reflected by the light-reflecting layer 50 and travel toward the light source 2, and are output from the second surface 10b of the phosphor substrate 10 as output light L3. Therefore, the second surface 10b of the phosphor substrate 10 is both a light incident surface and a light output surface.

[0067] For example, a case will be described in which light source 2 is a laser light source that emits blue laser light (light L1), and phosphor substrate 10 is a phosphor plate made of a yellow phosphor made of phosphor ceramics consisting only of YAG. In this case, when light L1, which is laser light emitted from light source 2, is incident on phosphor substrate 10, phosphor substrate 10 is excited by absorbing a portion of the laser light (blue light), and yellow fluorescence is generated in phosphor substrate 10 as light L2. Then, light L2, which is yellow light generated in phosphor substrate 10, and light L1, which is blue light that has entered phosphor substrate 10 and has not been wavelength-converted by phosphor substrate 10, are mixed together and output from second surface 10b of phosphor substrate 10.

[0068] [Manufacturing Method] Next, a manufacturing method of the wavelength conversion member 1 according to this embodiment will be described with reference to FIG. 3. FIG. 3 is a diagram for explaining the manufacturing method of the wavelength conversion member 1 according to this embodiment. The manufacturing method according to this embodiment includes a first step, a second step, and a third step. FIG. 3(a) is a diagram for explaining the first step, FIG. 3(b) is a diagram for explaining the second step, FIG. 3(c) is a diagram for explaining the third step, and FIG. 3(d) is a diagram for explaining a plurality of diced wavelength conversion members 1. In FIG. 3(a), (b), and (c), an enlarged view of the first surface 110a is further shown within the area surrounded by a dashed rectangular frame.

[0069] When manufacturing the wavelength conversion member 1, a first step is performed in which a phosphor substrate 110 having a plurality of pores 11 is prepared. More specifically, as shown in Fig. 3(a), the phosphor substrate 110 made of phosphor ceramic is prepared. More specifically, the phosphor substrate 110 is a substrate made only of phosphor ceramic.

[0070] For example, a phosphor sintered body ingot is sliced ​​with a wire saw to prepare a phosphor substrate 110 made of phosphor ceramic. The prepared phosphor substrate 110 is made of the same material as the phosphor substrate 10 described above, but has a larger area than the phosphor substrate 10. The phosphor substrate 110 is a mother substrate for cutting out a plurality of wavelength conversion members 1 from a bonded body 100 including the phosphor substrate 110, which will be described later.

[0071] Next, a second step is performed in which a burying layer 130 is formed above the phosphor substrate 110 by a wet process so as to fill the pores 11 exposed on the surface (e.g., the first surface 110a) of the phosphor substrate 110. More specifically, as shown in FIG. 3B, the burying layer 130 is formed on the first surface 110a of the phosphor substrate 110. This allows the pores 11 exposed on the first surface 110a of the phosphor substrate 110 to be filled with the burying layer 130. In other words, a portion of the burying layer 130 is embedded in the pores 11 exposed on the first surface 110a of the phosphor substrate 110. In this way, an anchor effect is generated by the burying layer 130 being embedded in the pores 11, making the burying layer 130 less likely to peel off from the phosphor substrate 110.

[0072] The buried layer 130 is formed by a wet process such as spin coating or spray coating, etc. At this time, the exposed surface (upper surface) of the buried layer 130 is a roughly flat and smooth surface.

[0073] Next, a third step is performed in which a light-reflecting layer 150 is formed above the embedding layer 130. More specifically, in the third step, as shown in (c) of FIG. 3, a bonding layer 140, a light-reflecting layer 150, and a bonding auxiliary layer 160 are formed in this order on the exposed surface of the embedding layer 130 (the surface opposite to the phosphor substrate 110 side). The bonding layer 140 can be made of the same material as the bonding layer 40 described above, the light-reflecting layer 150 can be made of the same material as the light-reflecting layer 50 described above, and the bonding auxiliary layer 160 can be made of the same material as the bonding auxiliary layer 60 described above.

[0074] The bonding layer 140, the light reflecting layer 150, and the bonding auxiliary layer 160 are formed by a dry process such as evaporation or chemical vapor deposition. At this time, by using a mask 200, the bonding layer 140, the light reflecting layer 150, and the bonding auxiliary layer 160 can be formed only at predetermined positions on the upper surface of the buried layer 130, rather than on the entire upper surface of the buried layer 130. The portion of the buried layer 130 covered by the mask 200 is the region 131. In other words, the region 131 of the buried layer 130 is a portion that does not overlap with the light reflecting layer 150 (more specifically, the bonding layer 140, the light reflecting layer 150, and the bonding auxiliary layer 160).

[0075] Since the bonding layer 140 is formed on the exposed surface, which is a flat and smooth surface, of the buried layer 130, the upper surface of the bonding layer 140 is also a flat and smooth surface. Therefore, the light reflecting layer 150 is formed on the flat and smooth surface of the bonding layer 140.

[0076] The first to third steps are performed to produce the bonded body 100. The bonded body 100 includes a phosphor substrate 110, an embedding layer 130, a bonding layer 140, a light reflecting layer 150, and a bonding auxiliary layer 160.

[0077] Next, as shown in Fig. 3(d), the bonded body 100 is divided to produce a plurality of wavelength conversion members 1. More specifically, the bonded body 100 is divided into a plurality of pieces by cutting the bonded body 100 with a dicing device for processing. Here, an example of dividing the bonded body 100 will be described with reference to Fig. 4.

[0078] FIG. 4 is a plan view of bonded body 100 according to this embodiment. For example, bonded body 100 is divided into a plurality of pieces by cutting it in the row and column directions along division lines shown by dashed dotted lines in FIG. 4 . This makes it possible to produce a plurality of wavelength conversion members 1, each of which has a rectangular shape in plan view. As an example, the shape of wavelength conversion member 1 in plan view is a rectangle with vertical and horizontal lengths of 1 mm to 10 mm. In the example shown in FIG. 4 , bonded body 100 is divided into nine pieces, that is, nine wavelength conversion members 1 are produced.

[0079] 4 , the division line indicated by the dashed dotted line is located in the region 131. That is, the joined body 100 is cut at the locations where the phosphor substrate 110 and the embedding layer 130 are provided, and the joined body 100 is not cut at the locations where the bonding layer 140, the light reflecting layer 150, and the bonding auxiliary layer 160 are provided. Note that by cutting the region 131 of the joined body 100, the region 131 becomes each of the regions 31 of the plurality of wavelength conversion members 1.

[0080] Although a dicing method using a dicing blade is exemplified, other known dicing methods may also be used, such as laser dicing using a laser, a method using a water jet laser, a combination of these, or a method of breaking after scribing.

[0081] 3 and 4 , in this embodiment, the joined body 100, which is formed by stacking the phosphor substrate 110, the embedding layer 130, the light reflecting layer 150, and the bonding auxiliary layer 160, is cut, and thereby a plurality of wavelength conversion members 1 are cut out from the joined body 100. In particular, by cutting the area 131, it is possible to produce a wavelength conversion member 1 in which the side surface of the phosphor substrate 10 and the side surface of the embedding layer 30 are substantially flush with each other over the entire periphery. Note that in FIG. 4 , the shape of the phosphor substrate 110 in a plan view is rectangular, but this is not limiting. For example, the shape of the phosphor substrate 110 in a plan view may be circular or another shape.

[0082] In summary, in this embodiment, the embedding layer 30 fills the multiple pores 11 exposed on the surface (first surface 10a) of the phosphor substrate 10, and the surface above the embedding layer 30 can be made flat and smooth. This allows the surface on which the light-reflecting layer 50 is provided to be made flat and smooth, thereby preventing the light-reflecting layer 50 from being interrupted at the multiple pores 11 and reducing the reflectance. Therefore, the light-reflecting layer 50 can efficiently reflect the excitation light (light L1) and the fluorescent light (light L2), and the luminous efficiency of the wavelength conversion member 1 can be increased.

[0083] Furthermore, because region 31 is provided, a portion corresponding to region 31 (region 131) can be cut during manufacturing. In this case, the portion where the phosphor substrate 10 and the burying layer 30 are formed is cut, meaning that the light-reflecting layer 50 and the bonding auxiliary layer 60, both made of a metal material, are not cut. When the light-reflecting layer 50 is made of a metal material, or the bonding auxiliary layer 60, both made of a metal material, has a large difference in thermal expansion coefficient from the phosphor substrate 10 or the burying layer 30 and bonding layer 40, both made of a dielectric material. Furthermore, because the light-reflecting layer 50 is formed using a dry process such as vapor deposition, the substrate temperature is high during formation. Therefore, at room temperature, stress is applied due to the difference in thermal expansion coefficient between the metal material and the dielectric material. If cutting is performed at a portion where the metal layer (the light-reflecting layer 50 and the bonding auxiliary layer 60, both made of a metal material) is formed, the stress generated during cutting may cause the metal layer to peel off. During cutting, the phosphor substrate 10 may chip, but due to the malleability of the metal layer, the light-reflecting layer 50 may peel off beyond the chipping region of the phosphor substrate 10. For example, in the technology disclosed in Patent Document 1, when the portion on the surface of the phosphor substrate where the bonding auxiliary layer is formed is cut, the bonding auxiliary layer is likely to peel off due to the mechanism described above because the difference between the thermal expansion coefficient of the phosphor substrate and the thermal expansion coefficient of the bonding auxiliary layer is large. With the technology disclosed in Patent Document 1, this peeling reduces the reliability of the wavelength conversion member.

[0084] However, in the present embodiment, the region 31 (the area where the phosphor substrate 10 and the embedding layer 30 are formed) is cut. Because the difference in thermal expansion coefficient between the phosphor substrate 10 and the embedding layer 30 made of a dielectric material is relatively small, even if the region 31 is cut, problems such as peeling off of the layers that make up the wavelength conversion member 1, such as the embedding layer 30, are unlikely to occur. Therefore, the reliability of the wavelength conversion member 1 can be improved.

[0085] 1 again, the area where the light reflecting layer 50 is formed will be described.

[0086] In the plan view shown in FIG. 1A, when the area where the light reflecting layer 50 is provided is defined as A and the area where the light reflecting layer 50 is not provided is defined as B, A and B satisfy the following formula.

[0087] 2≦A / B≦500

[0088] More specifically, the area (A) where the light reflecting layer 50 is provided is the area where the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60 are provided, and is the area occupied by the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60 in a plan view. In this embodiment, the area (A) where the light reflecting layer 50 is provided is the area of ​​the inner rectangle shown in (a) of FIG.

[0089] More specifically, the area (B) where the light reflecting layer 50 is not provided is the area (here, rectangular area) where the phosphor substrate 10 and the embedding layer 30 are provided, where the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60 are not provided. In this embodiment, the area (B) where the light reflecting layer 50 is not provided is the area of ​​the rectangular frame shape shown in (a) of FIG. 1 , and corresponds to the area of ​​region 31.

[0090] By satisfying the relationship A and B being 2≦A / B, the area of ​​the light-reflecting layer 50 can be made sufficiently large relative to the area of ​​the phosphor substrate 10 in a planar view, thereby widening the range into which light L1 (excitation light) from the light source 2 is incident. More specifically, in order to widen the area of ​​the light-reflecting layer 50 (the area that can be effectively used in the wavelength conversion member 1), chipping widths of approximately 3 μm may occur. Therefore, taking chipping widths into consideration, it is possible to narrow the width of the region 31 to approximately 5 μm. The wavelength conversion member 1 has a rectangular shape in a planar view, with vertical and horizontal lengths of 1 mm to 10 mm, so when the width of the region 31 is 5 μm, A / B is 49 to 500. Considering manufacturing tolerances, if the width of the region 31 is 90 μm, A / B is 2 to 28.

[0091] In this embodiment, the second surface 10b is exposed to the atmosphere, but may be provided with an AR (Anti Reflect) coating. By providing the AR coating, the reflectance of the phosphor substrate 10 for the light L1 (excitation light) from the light source 2 decreases, and the absorptance of the light L1 (excitation light) in the phosphor substrate 10 increases, so that more fluorescence can be output than in the case where there is no AR coating. The AR coating may be designed to reduce the reflectance at the wavelength to be used, and any known technology may be used.

[0092] [Modifications] Modifications of the embodiment will be described below, focusing on differences from the embodiment, and omitting or simplifying the description of commonalities.

[0093] FIG. 5 is a cross-sectional view showing the configuration of a wavelength conversion member 1a according to a modified example of the embodiment.

[0094] The wavelength conversion member 1a according to this modification includes a phosphor substrate 10, an embedding layer 30a, a bonding layer 40a, a light reflecting layer 50a, and a bonding auxiliary layer 60a.

[0095] The buried layer 30a according to this modification has the same configuration as the buried layer 30, except that it does not have the region 31. The bonding layer 40a, the light reflecting layer 50a, and the bonding auxiliary layer 60a have the same configuration as the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60, respectively, except that they have different shapes.

[0096] In this modification, the region 31 is not provided in the embedding layer 30a, but instead the thicknesses of the bonding layer 40a, the light reflecting layer 50a, and the bonding auxiliary layer 60a at the ends of the wavelength conversion member 1a corresponding to the region 31 are thinner than the thicknesses of the bonding layer 40a, the light reflecting layer 50a, and the bonding auxiliary layer 60a at the center of the wavelength conversion member 1a. That is, the thicknesses of the ends of the bonding layer 40a, the light reflecting layer 50a, and the bonding auxiliary layer 60a are thinner than the thicknesses of the centers of the bonding layer 40a, the light reflecting layer 50a, and the bonding auxiliary layer 60a. From the viewpoint of peeling, it is better to provide the region 31, but by reducing the thicknesses of the light reflecting layer 50a and the bonding auxiliary layer 60a, internal stress is reduced, and peeling can be reduced. That is, in this modification, when cutting as shown in FIG. 3 , the light-reflecting layer 50a made of a metal material is cut. However, because the thickness of the end of the light-reflecting layer 50a is thin, internal stress can be reduced and peeling can be suppressed compared to when the thickness of the bonding auxiliary layer is uniform (see Patent Document 1). Furthermore, in this modification, the thickness of the end of the bonding auxiliary layer 60a is also thin, further reducing internal stress and further suppressing peeling. Furthermore, the effectively usable area of ​​the wavelength conversion member 1a can be expanded to near the end of the wavelength conversion member 1a. By utilizing the wraparound of material around the mask during film formation, the thickness of the end of each of the bonding layer 40a, the light-reflecting layer 50a, and the bonding auxiliary layer 60a can be reduced.

[0097] In addition, "a layer being thinner than the center" means that the layer thickness is thinner than the center by even a small amount, for example, it may be 80% or less, or even 60% or less. Furthermore, the center of a layer refers to the center between the left and right ends of the layer in the cross-sectional view shown in Figure 5, for example. Therefore, as shown in Figure 5, the thickness d2 of the edge of the light-reflecting layer 50a is thinner than the thickness d1 of the center of the light-reflecting layer 50a.

[0098] Regions A2 are defined as regions in which the thicknesses of the bonding layer 40a, the light reflecting layer 50a, and the bonding auxiliary layer 60a are thinner than the thicknesses of the central portions of the bonding layer 40a, the light reflecting layer 50a, and the bonding auxiliary layer 60a. Region A2 has the same meaning as region 31, and the required region width is also the same as region 31. Regions A1 are defined as regions in which the thicknesses of the bonding layer 40a, the light reflecting layer 50a, and the bonding auxiliary layer 60a are the same as (i.e., the same as) the thicknesses of the central portions of the bonding layer 40a, the light reflecting layer 50a, and the bonding auxiliary layer 60a. When viewed in plan, the region area Aa is defined as the area of ​​region A1, and the region area Ba is defined as the area of ​​region A2, where Aa and Ba satisfy the following formula:

[0099] 2≦Aa / Ba≦500

[0100] In region A2, the thicknesses of the bonding layer 40a, the light-reflecting layer 50a, and the bonding auxiliary layer 60a become thinner toward the edges. Region A2 has a rectangular frame shape in a plan view, and a rectangular region A1 is provided inside the frame shape. The side surfaces (side end faces) of the phosphor substrate 10, the side surfaces (side end faces) of the embedding layer 30a, the side surfaces (side end faces) of the bonding layer 40a, the side surfaces (side end faces) of the light-reflecting layer 50a, and the side surfaces (side end faces) of the bonding auxiliary layer 60a are substantially flush with each other. In this modified example, the side surfaces of the phosphor substrate 10, the side surfaces of the embedding layer 30a, the side surfaces of the bonding layer 40a, the side surfaces of the light-reflecting layer 50a, and the side surfaces of the bonding auxiliary layer 60a are substantially flush with each other all around.

[0101] [Effects, etc.] Invention 1 is a wavelength conversion member 1 comprising a phosphor substrate 10 having a plurality of pores 11, a buried layer 30 provided above the phosphor substrate 10 and filling the plurality of pores 11 exposed on the surface of the phosphor substrate 10, and a light-reflecting layer 50 provided above the buried layer 30, wherein, in a planar view of the phosphor substrate 10, the buried layer 30 has an area 31 that does not overlap with the light-reflecting layer 50.

[0102] As a result, the embedding layer 30 fills the multiple pores 11 exposed on the surface (first surface 10a) of the phosphor substrate 10, and the surface above the embedding layer 30 can be made flat and smooth. In other words, since the surface on which the light-reflecting layer 50 is provided can be made flat and smooth, the light-reflecting layer 50 is prevented from being interrupted at the multiple pores 11, preventing a decrease in reflectance. Therefore, the light-reflecting layer 50 can efficiently reflect the excitation light (light L1) and the fluorescent light (light L2), thereby increasing the luminous efficiency of the wavelength conversion member 1.

[0103] Furthermore, since the region 31 is provided, the portion corresponding to the region 31 can be cut during manufacturing. In this case, the portion where the phosphor substrate 10 and the embedding layer 30 are formed is cut, meaning that the light-reflecting layer 50 and the bonding auxiliary layer 60, which are made of a metal material, are not cut. Because the difference between the thermal expansion coefficient of the phosphor substrate 10 and the thermal expansion coefficient of the embedding layer 30, which is made of a dielectric material, is relatively small, even if the region 31 is cut, problems such as peeling of the layers that make up the wavelength conversion member 1, such as the embedding layer 30, are unlikely to occur. Therefore, the reliability of the wavelength conversion member 1 can be improved.

[0104] In summary, it is possible to realize a wavelength conversion member 1 with high luminous efficiency and reliability.

[0105] A second aspect of the present invention is the wavelength conversion member 1 according to the first aspect of the present invention, further comprising a bonding layer 40 provided above the embedding layer 30 , and the light reflecting layer 50 provided above the bonding layer 40 .

[0106] This allows the embedding layer 30 and the light reflecting layer 50 to be bonded more firmly, making them less likely to peel off, and making it possible to realize a wavelength conversion member 1 with higher reliability.

[0107] A third aspect of the present invention is the wavelength conversion member 1 according to the first or second aspect of the present invention, further comprising a bonding auxiliary layer 60 provided above the light reflecting layer 50 .

[0108] This makes it possible to easily bond the wavelength conversion member 1 to a substrate (for example, the support substrate 20) for supporting the wavelength conversion member 1.

[0109] Invention 4 is the wavelength conversion member 1 according to any one of Inventions 1 to 3, in which, when viewed in a plane, A represents an area where the light reflecting layer 50 is provided, and B represents an area where the light reflecting layer 50 is not provided, and A and B satisfy the formula (2≦A / B≦500).

[0110] This makes it possible to widen the range into which the light L1 (excitation light) from the light source 2 is incident, and also makes it possible to easily manufacture the wavelength conversion member 1.

[0111] Invention 5 is the wavelength conversion member 1 according to any one of Inventions 1 to 4, wherein, when the thickness of the buried layer 30 is C and the average size of the plurality of pores 11 is D, C and D satisfy the following formula (D / 3≦C≦3×D):

[0112] This allows the buried layer 30 to have a smooth, flat surface, and also allows the heat of the phosphor substrate 10 to be sufficiently dissipated.

[0113] Invention 6 is a wavelength conversion member 1a comprising a phosphor substrate 10 having a plurality of pores 11, a buried layer 30a provided above the phosphor substrate 10 and filling the plurality of pores 11 exposed on the surface of the phosphor substrate 10, and a light-reflecting layer 50a provided above the buried layer 30a, wherein the thickness of the light-reflecting layer 50a at the ends is thinner than the thickness of the light-reflecting layer 50a at the center.

[0114] As a result, the embedding layer 30a fills the multiple pores 11 exposed on the surface (first surface 10a) of the phosphor substrate 10, and the surface above the embedding layer 30a can be made flat and smooth. In other words, since the surface on which the light-reflecting layer 50a is provided can be made flat and smooth, the light-reflecting layer 50a is prevented from being interrupted at the multiple pores 11, preventing a decrease in reflectance. Therefore, the light-reflecting layer 50a can efficiently reflect the excitation light (light L1) and the fluorescent light (light L2), thereby increasing the luminous efficiency of the wavelength conversion member 1a.

[0115] Furthermore, since the thickness of the light reflecting layer 50a at the edges is thinner than the thickness of the light reflecting layer 50a at the center, internal stress is reduced, which can reduce peeling of the light reflecting layer 50a, etc. Therefore, the reliability of the wavelength conversion member 1a can be improved.

[0116] In summary, it is possible to realize a wavelength conversion member 1 with high luminous efficiency and reliability.

[0117] A seventh aspect of the present invention is a phosphor device 3 comprising a wavelength conversion member according to any one of the first to sixth aspects (for example, wavelength conversion member 1 or 1a) and a support substrate 20 that supports the wavelength conversion member.

[0118] As described above, the wavelength conversion member (for example, the wavelength conversion member 1 or 1a) is a member with high luminous efficiency and reliability. Similarly, the phosphor device 3 including such a wavelength conversion member 1 is a device with high luminous efficiency and reliability.

[0119] Invention 8 is a method for manufacturing a wavelength conversion member 1, which includes a first step of preparing a phosphor substrate 110 having a plurality of pores 11, a second step of forming a buried layer 130 above the phosphor substrate 110 by a wet process so as to fill the plurality of pores 11 exposed on the surface of the phosphor substrate 110, and a third step of forming a light-reflecting layer 150 above the buried layer 130, wherein, in a planar view of the phosphor substrate 110, the buried layer 130 has a region 131 that does not overlap with the light-reflecting layer 150.

[0120] As a result, the embedding layer 130 fills the multiple pores 11 exposed on the surface (first surface 110a) of the phosphor substrate 110, and the surface above the embedding layer 130 can be made flat and smooth. In other words, since the surface on which the light-reflecting layer 150 is provided can be made flat and smooth, the light-reflecting layer 150 is prevented from being interrupted at the multiple pores 11, preventing a decrease in reflectance. Therefore, the light-reflecting layer 150 can efficiently reflect the excitation light (light L1) and the fluorescent light (light L2), and the luminous efficiency of the wavelength conversion member 1 can be increased.

[0121] Furthermore, since the region 131 is provided, the region 131 can be cut during manufacturing. In this case, the region 131 where the phosphor substrate 110 and the embedding layer 130 are formed is cut, meaning that the light reflecting layer 50 and the bonding auxiliary layer 60, which are made of a metal material, are not cut. Because the difference between the thermal expansion coefficient of the phosphor substrate 110 and the thermal expansion coefficient of the embedding layer 130 made of a dielectric material is relatively small, even if the region 131 is cut, problems such as peeling of the embedding layer 130 are unlikely to occur. Therefore, the reliability of the wavelength conversion member 1 can be improved.

[0122] In summary, the manufacturing method according to this embodiment makes it possible to realize a wavelength conversion member 1 with high luminous efficiency and reliability.

[0123] (Others) Although the phosphor substrate and the like according to the present invention have been described based on the above-mentioned embodiment, the present invention is not limited to the above-mentioned embodiment and modifications.

[0124] Although the phosphor substrate 10 is made of only phosphor ceramics, i.e., does not contain a binder, the present invention is not limited to this. The phosphor substrate 10 may contain phosphor ceramics and other materials, such as particles having light scattering properties (light diffusibility), or may contain a binder.

[0125] In the embodiment and modified examples, the planar shapes of the phosphor substrate 10 and the embedding layer 30 are rectangular, and the planar shapes of the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60 are rectangular, but this is not limited to this. Considering that the bonded body 100 will be cut, the planar shapes of the phosphor substrate 10 and the embedding layer 30 and the planar shapes of the bonding layer 40, the light reflecting layer 50, and the bonding auxiliary layer 60 may be polygonal shapes other than rectangular, and are particularly preferably triangular or hexagonal.

[0126] In addition, the present invention also includes forms obtained by applying various modifications to each embodiment that a person skilled in the art would think of, and forms realized by arbitrarily combining the components and functions of each embodiment within the scope of the present invention.

[0127] REFERENCE SIGNS LIST 1, 1a Wavelength conversion member 3 Phosphor device 10, 110 Phosphor substrate 11 Pore 20 Support substrate 30, 30a, 130 Buried layer 31, 131 Region 40, 40a, 140 Bonding layer 50, 50a, 150 Light reflecting layer 60, 60a, 160 Bonding auxiliary layer A1, A2 Region

Claims

1. A wavelength conversion member comprising: a phosphor substrate having a plurality of pores; a buried layer provided above the phosphor substrate and filling the plurality of pores exposed on the surface of the phosphor substrate; and a light-reflecting layer provided above the buried layer, wherein, in a planar view of the phosphor substrate, the buried layer has an area that does not overlap with the light-reflecting layer.

2. The wavelength conversion member according to claim 1, further comprising a bonding layer provided above the embedding layer, wherein the light reflecting layer is provided above the bonding layer.

3. The wavelength conversion member according to claim 1, further comprising a bonding auxiliary layer provided above the light reflecting layer.

4. The wavelength conversion member according to claim 1, wherein, in the planar view, the area where the light reflecting layer is provided is A and the area where the light reflecting layer is not provided is B, A and B satisfy the following formula: 2≦A / B≦500.

5. The wavelength conversion member according to claim 1, wherein C is the thickness of the buried layer and D is the average size of the plurality of pores, and C and D satisfy the following formula: D / 3≦C≦3×D.

6. A wavelength conversion member comprising: a phosphor substrate having a plurality of pores; a filling layer provided above the phosphor substrate and filling the plurality of pores exposed on the surface of the phosphor substrate; and a light reflecting layer provided above the filling layer, wherein the thickness of the light reflecting layer at the ends is thinner than the thickness of the light reflecting layer at the center.

7. A phosphor device comprising: a wavelength conversion member according to any one of claims 1 to 6; and a support substrate that supports the wavelength conversion member.

8. A method for manufacturing a wavelength conversion member, comprising: a first step of preparing a phosphor substrate having a plurality of pores; a second step of forming a buried layer above the phosphor substrate by a wet process so as to fill the plurality of pores exposed on the surface of the phosphor substrate; and a third step of forming a light-reflecting layer above the buried layer, wherein, in a planar view of the phosphor substrate, the buried layer has an area that does not overlap with the light-reflecting layer.

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