Substrate and light-emitting device

Abstract

The present invention provides a substrate and a light-emitting device excellent in heat dissipation. A substrate according to an embodiment of the present disclosure comprises a first member having a through-hole penetrating from an upper surface to a lower surface, and a second member disposed inside the through-hole. The second member includes: a first region including graphite; a second region disposed outside the first region in a top view, the second region including graphite and a thermally conductive material containing a metal and / or a ceramic, and having a volume fraction of graphite lower than that in the first region; and a third region disposed outside the second region in a top view, the third region including a thermally conductive material containing a metal and / or a ceramic, and having a volume fraction of the thermally conductive material higher than that in the second region. A light-emitting device according to an embodiment of the present disclosure comprises the substrate and a light source unit disposed above the substrate.

Description

Substrate and light-emitting device

[0001] The present disclosure relates to a substrate and a light emitting device.

[0002] In light-emitting devices, there is a demand for improved heat dissipation from the viewpoint of increasing the brightness of light-emitting elements, etc. Patent Document 1 discloses a clad material suitable for heat sinks for electronic component mounting substrates, in which Mo—Cu layers are laminated, via metal films, on both sides of a Cu-graphite layer made of a sintered body of graphite powder with a Cu coating formed on the surface.

[0003] International Publication No. 2019 / 116946

[0004] The present disclosure provides a substrate and a light emitting device with excellent heat dissipation properties.

[0005] A substrate according to one embodiment of the present disclosure comprises a first member having a through hole extending from an upper surface to a lower surface, and a second member disposed inside the through hole, wherein the second member comprises: a first region containing graphite; a second region disposed outside the first region in a top view, the second region containing graphite and a thermally conductive material containing at least one of a metal and a ceramic, the volume fraction of the graphite being lower than the volume fraction of the graphite in the first region; and a third region disposed outside the second region in a top view, the third region containing a thermally conductive material containing at least one of a metal and a ceramic, the volume fraction of the thermally conductive material being higher than the volume fraction of the thermally conductive material in the second region.

[0006] A light emitting device according to one embodiment of the present disclosure comprises a substrate and a light source unit arranged above the substrate, the substrate comprising a first member having a through hole extending from an upper surface to a lower surface, and a second member arranged inside the through hole, the second member comprising: a first region including graphite and arranged in a position overlapping with the light source unit in a top view; a second region arranged outside the first region in a top view, the second region including graphite and a thermally conductive material containing at least one of a metal and a ceramic, the second region having a volume fraction of graphite lower than the volume fraction of the graphite in the first region; and a third region arranged outside the second region in a top view, the third region including a thermally conductive material containing at least one of a metal and a ceramic, the third region having a volume fraction of the thermally conductive material higher than the volume fraction of the thermally conductive material in the second region.

[0007] According to an embodiment of the present disclosure, a substrate and a light emitting device with excellent heat dissipation properties can be provided.

[0008] 6A is a schematic top view showing an example of a light emitting device according to the first embodiment. FIG. 6B is a schematic cross-sectional view of the light emitting device according to the first embodiment taken along line II-II in FIG. 1 . FIG. 6C is a schematic cross-sectional view of a light emitting device according to Modification 1 of the first embodiment. FIG. 6D is a schematic cross-sectional view of a light emitting device according to Modification 1 of the second embodiment. FIG. 6E is a schematic cross-sectional view of a light emitting device according to Modification 2 of the second embodiment. FIG. 6F is a partial enlarged cross-sectional view of region VIB shown in FIG. 6A . FIG. 6G is a schematic cross-sectional view of a light emitting device according to Modification 3 of the second embodiment. FIG. 6H is a schematic cross-sectional view for explaining a method for manufacturing a substrate according to the embodiment. FIG. 6I is a schematic cross-sectional view for explaining a method for manufacturing a substrate according to the embodiment. FIG. 6J is a schematic cross-sectional view for explaining a method for manufacturing a substrate according to the embodiment. FIG. 6J is a schematic cross-sectional view for explaining a method for manufacturing a substrate according to the embodiment. FIG. 6J is a schematic cross-sectional view for explaining a method for manufacturing a substrate according to the embodiment. 1A and 1B are schematic cross-sectional views for explaining a method for manufacturing a light emitting device according to an embodiment;

[0009] Light-emitting devices according to embodiments of the present disclosure will be described in detail below with reference to the drawings. However, the following embodiments are merely illustrative of light-emitting devices that embody the technical concepts of the embodiments and are not limited thereto. Furthermore, unless otherwise specified, the dimensions, materials, shapes, and relative arrangements of components described in the embodiments are merely illustrative examples and are not intended to limit the scope of the present disclosure. The size, positional relationships, etc. of components shown in each drawing may be exaggerated for clarity. In the following description, the same names and symbols indicate identical or similar components, and detailed descriptions will be omitted as appropriate. An end view showing only a cut surface may be used as a cross-sectional view.

[0010] In the figures shown below, directions may be indicated by the X-axis, Y-axis, and Z-axis. The X-axis, Y-axis, and Z-axis are mutually orthogonal. The direction of the arrow in the X-axis direction is denoted as the +X direction, and the direction opposite to the +X direction is denoted as the -X direction. The direction of the arrow in the Y-axis direction is denoted as the +Y direction, and the direction opposite to the +Y direction is denoted as the -Y direction. The direction of the arrow in the Z-axis direction is denoted as the +Z direction, and the direction opposite to the +Z direction is denoted as the -Z direction. Furthermore, in the terms used in the embodiments, "top view" refers to viewing an object from the +Z direction. However, this does not limit the orientation of the light-emitting device during use, and the orientation of the light-emitting device is arbitrary. Furthermore, in the embodiments, the surface of an object viewed from the +Z direction is referred to as the "top surface," and the surface of the object viewed from the -Z direction is referred to as the "bottom surface." In the embodiments shown below, "along the X-axis, Y-axis, and Z-axis" includes the object being tilted within a range of ±10° relative to these axes. In addition, in the embodiment, the orthogonal angle may have an error of ±10° relative to 90°.

[0011] Furthermore, in this disclosure, polygons such as triangles and quadrilaterals are referred to as polygons, including shapes in which the corners of the polygons have been processed, such as by rounding, chamfering, corner removal, or rounding. Shapes in which processing has been applied not only to the corners (edges of the edges) but also to the middle portions of the edges are also referred to as polygons. In other words, shapes in which partial processing has been applied while retaining the polygon as a base are included in the interpretation of "polygon" described in this disclosure.

[0012] The same applies to terms that represent specific shapes, such as trapezoids, circles, and irregularities, not just polygons. The same also applies to terms that refer to the sides that form those shapes. In other words, even if the corners or middle portions of a side are processed, the interpretation of "side" includes the processed portions. Note that when distinguishing a "polygon" or "side" that has no processing from a processed shape, the word "strict" is added, for example, "strict quadrangle."

[0013] [First embodiment] <Overall configuration example of light emitting device 1> The overall configuration of the light emitting device 1 according to the first embodiment will be described with reference to Figures 1 and 2. Figure 1 is a schematic top view showing an example of the light emitting device 1 according to the first embodiment. Figure 2 is a schematic cross-sectional view of the light emitting device 1 taken along line II-II in Figure 1.

[0014] As shown in Figures 1 and 2, the light emitting device 1 includes a substrate 10 and a light source unit 20. The light emitting device 1 further includes a bonding member 30 and a covering member 40. The light emitting device 1 is mounted on a circuit board. The light emitting device 1 is connected to other electronic components, etc., via the circuit board. For convenience of illustration, in Figure 1, portions of the wavelength conversion member 24 and the covering member 40 in the light source unit 20 are omitted, and portions of the substrate 10 and the light source unit 20 that are covered by the wavelength conversion member 24 or the covering member 40 are visualized.

[0015] <Substrate 10> The configuration of the substrate 10 will be described. The substrate 10 is a plate-like member having a substantially rectangular outer shape when viewed from above. However, the substrate 10 may have other outer shapes, such as a substantially circular, elliptical, rectangular, or polygonal shape when viewed from above.

[0016] 2, the substrate 10 includes a first member 11 and a second member 12. In the first embodiment, the thickness (dimension along the Z-axis direction) of the first member 11 and the thickness (dimension along the Z-axis direction) of the second member 12 are substantially the same. However, the thickness of the first member 11 and the thickness of the second member 12 may be different from each other. The substrate 10 further includes an adhesive member 13, a first terminal 14, a second terminal 15, internal wiring 16, and metal films 17a and 17b.

[0017] The first member 11 is disposed outside the second member 12 and the adhesive member 13. When viewed from above, the first member 11 has a frame-like shape that surrounds the second member 12 and the adhesive member 13. However, the first member 11 is not limited to having a continuous shape such as a frame. For example, the first member 11 may be composed of two or more plate-like members that are disposed so as to sandwich the second member 12 when viewed from above.

[0018] The first member 11 has an upper surface 111a, a lower surface 111b, one or more side surfaces 111c connecting the outer edges of the upper surface 111a and the lower surface 111b, and a through-hole 112 penetrating from the upper surface 111a to the lower surface 111b. The through-hole 112 is defined by a surface 111d connecting the inner edges of the upper surface 111a and the lower surface 111b. As shown in FIG. 2 , the through-hole 112 is located toward the center of the first member 11 in a cross-sectional view. The surface 111d surrounds the second member 12 in a top view. Note that the surface 111d will be referred to as the "surface 111d defining the through-hole 112" hereinafter. This also applies to the modified example of the first embodiment, the second embodiment, and each modified example of the second embodiment, which will be described separately with reference to FIGS. 3 to 7 . In the first embodiment, the surface 111d defining the through-hole 112 is aligned along the Z-axis direction.

[0019] The first member 11 is preferably made of ceramics with excellent thermal conductivity, such as aluminum nitride, aluminum oxide, silicon carbide, or silicon nitride, or resins with excellent thermal conductivity, such as glass epoxy, although the material constituting the first member 11 is not limited to these.

[0020] The second member 12 is disposed inside the through-hole 112. The second member 12 supports the light source unit 20. The second member 12 is a plate-like member having a substantially rectangular outer shape when viewed from above. However, the second member 12 may have other outer shapes, such as a substantially circular shape, a substantially elliptical shape, or a substantially polygonal shape when viewed from above.

[0021] 2, the second member 12 has an upper surface 121a, a lower surface 121b, and a side surface 121c connecting the outer edges of the upper surface 121a and the lower surface 121b. Hereinafter, the side surface 121c of the second member 12 will be referred to as the "surface 121c located on the outer periphery of the second member 12." The same applies to the modified example of the first embodiment, the second embodiment, and each modified example of the second embodiment, which will be described separately with reference to FIGS. 3 to 7.

[0022] The second member 12 includes a first region 124, a second region 125, and a third region 126. The first region 124 is disposed at a central position of the second member 12 in a top view. The second region 125 is disposed outside the first region 124 in a top view. The second region 125 disposed on the +Y direction side and the second region 125 disposed on the −Y direction side sandwich the first region 124. The third region 126 is disposed outside the second region 125 in a top view. The third region 126 disposed on the +Y direction side and the third region 126 disposed on the −Y direction side sandwich the first region 124 and the second region 125. The third region 126 is disposed at an end of the second member 12. 2, the surface 121c located on the outer periphery of the second member 12 corresponds to the side surface connecting the outer edges of the upper surface (surface on the +Z direction side) and the lower surface (surface on the −Z direction side) of the third region 126. In the first embodiment, the surface 121c located on the outer periphery of the second member 12 is aligned along the Z-axis direction.

[0023] The first region 124 includes graphite. When viewed from above, the first region 124 overlaps with many of the light emitting elements 21 in the light source unit 20, and includes graphite, which has excellent thermal conductivity, thereby improving the heat dissipation of the second member 12. As a result, the heat dissipation of the substrate 10 can be improved.

[0024] The volume fraction of graphite in the first region 124 is preferably 70 vol% or more and 100 vol% or less. If the volume fraction of graphite in the first region 124 is less than 70 vol%, the desired heat dissipation efficiency of the second member 12 may not be ensured. The "volume fraction" of substance M in region A refers to the percentage of the volume of the portion of region A occupied by substance M with respect to the total volume of region A. For example, if region A is the first region 124 and substance M is graphite, the "volume fraction of graphite in the first region 124" corresponds to the percentage of the volume of the portion of first region 124 occupied by graphite with respect to the total volume of first region 124.

[0025] The volume fraction of graphite in first region 124 may be uniform regardless of the position in first region 124. Alternatively, the volume fraction of graphite in first region 124 may vary depending on the position in first region 124. For example, the volume fraction of graphite in first region 124 may vary continuously from the center of first region 124 toward the outside.

[0026] The first region 124 may also contain other substances, such as a thermally conductive material containing at least one of a metal and a ceramic. Including the first region 124 in a thermally conductive material containing at least one of a metal and a ceramic can improve the strength of the second member 12. Examples of metals in the thermally conductive material include copper, aluminum, nickel, titanium, platinum, gold, and silver. However, the metals in the thermally conductive material are not limited to these. Examples of ceramics in the thermally conductive material include aluminum nitride, aluminum oxide, silicon carbide, and silicon nitride. However, the ceramics in the thermally conductive material are not limited to these. Among these thermally conductive materials containing at least one of a metal and a ceramic, copper and aluminum are preferred, due to their excellent thermal conductivity and processability. Hereinafter, a thermally conductive material containing at least one of a metal and a ceramic will be referred to as a "thermally conductive material."

[0027] The volume fraction of the thermally conductive material in the first region 124 may be uniform regardless of the position in the first region 124. Alternatively, the volume fraction of the thermally conductive material in the first region 124 may vary depending on the position in the first region 124. For example, the volume fraction of the thermally conductive material in the first region 124 may vary continuously from the center to the outside of the first region 124. In particular, from the viewpoint of improving the strength of the second member 12, it is preferable that the volume fraction of the thermally conductive material in the first region 124 increase from the center to the outside of the first region 124.

[0028] From the viewpoint of improving the heat dissipation properties of the second member 12 and improving the strength of the second member 12, the volume fraction of graphite in the first region 124 may continuously decrease from the center of the first region 124 to the outside, and the volume fraction of the thermally conductive material in the first region 124 may continuously increase from the center of the first region 124 to the outside.

[0029] The second region 125 includes graphite and a thermally conductive material. The second region 125 may include a substance other than graphite and a thermally conductive material. By including both graphite and a thermally conductive material in the second region 125 in addition to the first region 124, the heat dissipation and strength of the second member 12 can be improved.

[0030] The volume fraction of graphite in second region 125 is lower than the volume fraction of graphite in first region 124. In other words, by increasing the volume fraction of graphite in first region 124, which overlaps with many light-emitting elements 21 in light source unit 20 in top view, compared to the volume fraction of graphite in second region 125, which is disposed outside first region 124, the heat dissipation properties of the second member can be further improved.

[0031] The volume fraction of graphite in the second region 125 is preferably 30 vol% or more and 70 vol% or less. If the volume fraction of graphite in the second region 125 is less than 30 vol%, it may not be possible to ensure the desired heat dissipation efficiency of the second member 12. Furthermore, if the volume fraction of graphite in the second region 125 is more than 70 vol%, the strength of the second member 12 may be reduced.

[0032] The volume fraction of graphite in second region 125 may be uniform regardless of the position in second region 125. Alternatively, the volume fraction of graphite in second region 125 may vary depending on the position in second region 125. For example, the volume fraction of graphite in second region 125 may vary continuously from the inside to the outside of second region 125.

[0033] When the first region 124 contains a thermally conductive material, the volume fraction of the thermally conductive material in the second region 125 is higher than the volume fraction of the thermally conductive material in the first region 124. By increasing the volume fraction of the thermally conductive material in the second region 125 compared to the volume fraction of the first region 124 disposed inside the second region 125 in a top view, the strength of the second member 12 can be further improved.

[0034] The volume fraction of the thermally conductive material in the second region 125 may be uniform regardless of the position in the second region 125. Alternatively, the volume fraction of the thermally conductive material in the second region 125 may vary depending on the position in the second region 125. For example, the volume fraction of the thermally conductive material in the second region 125 may vary continuously from the inside to the outside of the second region 125. In particular, from the viewpoint of improving the strength of the second member, it is preferable that the volume fraction of the thermally conductive material in the second region 125 increase from the inside to the outside of the second region 125.

[0035] From the viewpoint of improving the heat dissipation properties of the second member 12 and improving the strength of the second member 12, the volume fraction of graphite in the second region 125 may continuously decrease from the inside to the outside of the second region 125, and the volume fraction of the thermally conductive material in the second region 125 may continuously increase from the inside to the outside of the second region 125.

[0036] The third region 126 contains a thermally conductive material. The volume fraction of the thermally conductive material in the third region 126 is higher than the volume fraction of the thermally conductive material in the second region 125. That is, by increasing the volume fraction of the thermally conductive material in the third region 126, which is in contact with another member of the second member 12, such as the adhesive member 13, compared to the volume fraction of the thermally conductive material in the second region 125, which is located inside the third region 126, the strength of the second member 12 can be further improved. Furthermore, by increasing the volume fraction of the thermally conductive material in the third region 126 compared to the volume fraction of the thermally conductive material in the second region 125, it is possible to easily process the end portions of the second member 12, such as the surface 121c located on the outer periphery of the second member 12.

[0037] The volume fraction of the thermally conductive material in the third region 126 may be uniform regardless of the position in the third region 126. Alternatively, the volume fraction of the thermally conductive material in the third region 126 may vary depending on the position in the third region 126. For example, the volume fraction of the thermally conductive material in the third region 126 may vary continuously from the inside to the outside of the third region 126. In particular, from the viewpoint of improving the strength and processability of the second member 12, it is preferable that the volume fraction of the thermally conductive material in the third region 126 increases from the inside to the outside of the third region 126. The third region 126 may be formed only from the thermally conductive material.

[0038] The third region 126 may contain other substances such as graphite. From the viewpoint of improving the strength and processability of the second member 12, it is preferable that the volume fraction of graphite in the third region 126 be lower than the volume fraction of graphite in the second region 125.

[0039] The volume fraction of graphite in third region 126 may be uniform regardless of the position in third region 126. Alternatively, the volume fraction of graphite in third region 126 may vary depending on the position in third region 126. For example, the volume fraction of graphite in third region 126 may vary continuously from the inside to the outside of third region 126.

[0040] From the viewpoint of improving the heat dissipation properties of the second member 12 and improving the strength and processability of the second member 12, the volume fraction of graphite in the third region 126 may continuously decrease from the inside to the outside of the third region 126, and the volume fraction of the thermally conductive material in the third region 126 may continuously increase from the inside to the outside of the third region 126.

[0041] In the second member 12, the volume fraction of graphite decreases in the order of the first region 124, the second region 125, and the third region 126. The volume fraction of graphite may continuously decrease from the center of the second member 12, where the first region 124 is located, to the end of the second member 12, where the third region 126 is located.

[0042] In the second member 12, the volume fraction of the thermally conductive material increases in the order of the first region 124, the second region 125, and the third region 126. The volume fraction of the thermally conductive material may continuously increase from the center of the second member 12, where the first region 124 is located, to the end of the second member 12, where the third region 126 is located. The thermally conductive material in the first region 124, the second region 125, and the third region 126 each preferably contain at least one of copper and aluminum. The first region 124, the second region 125, and the third region 126 may each contain the same type of thermally conductive material or different types of thermally conductive materials. Note that, for example, if the end of the second member 12 is not processed, the third region 126 may not be provided.

[0043] When the width dimension (dimension along the Y-axis direction) of the second member 12 is taken as 100%, the ratio of the width dimension (dimension along the Y-axis direction) of the first region 124 to the width dimension of the second member 12 is, for example, 40% or more and 80% or less. The ratio of the width dimension of the second region 125 arranged on the +Y direction side to the width dimension of the second member 12 is, for example, 5% or more and 15% or less, and the ratio of the width dimension of the second region 125 arranged on the −Y direction side to the width dimension of the second member 12 is, for example, 5% or more and 15% or less. The ratio of the width dimension of the third region 126 arranged on the +Y direction side to the width dimension of the second member 12 is, for example, 5% or more and 15% or less, and the ratio of the width dimension of the third region 126 arranged on the −Y direction side to the width dimension of the second member 12 is, for example, 5% or more and 15% or less. However, the ratios of the width dimensions of the first region 124, the second region 125, and the third region 126 to the width dimension of the second member 12 are not limited to these.

[0044] The adhesive member 13 is disposed between the first member 11 and the second member 12. The adhesive member 13 fixes the second member 12 to the inside of the through-hole 112 of the first member 11. As shown in FIG. 2 , the outer edge of the adhesive member 13 contacts a surface 111d that defines the through-hole 112 of the first member 11. The inner edge of the adhesive member 13 contacts a surface 121c located on the outer periphery of the second member 12.

[0045] Examples of materials that can be used to form the adhesive member 13 include resin materials such as epoxy resin, acrylic resin, urethane resin, and silicone resin, conductive paste materials in which metal powder is mixed into a resin material, and metal materials, but the materials that can be used to form the adhesive member 13 are not limited to these.

[0046] The first terminal 14 is provided on the upper surface 111a of the first member 11. The upper surface (the surface on the +Z direction side) of the first terminal 14 is connected to one end of the thin conductor wire 50. The other end of the thin conductor wire 50 is connected to the third terminal 221 arranged on the upper surface (the surface on the +Z direction side) of the wiring substrate 22 in the light source unit 20. In other words, the first terminal 14 and the third terminal 221 are electrically connected via the thin conductor wire 50.

[0047] The second terminal 15 is provided on the lower surface 111b of the first member 11. The lower surface (the surface on the -Z direction side) of the second terminal 15 is connected to, for example, wiring provided on the upper surface (the surface on the +Z direction side) of the circuit board. The wiring provided on the upper surface of the circuit board is electrically connected to an external power supply. In other words, the second terminal 15 is electrically connected to the external power supply via the wiring provided on the upper surface of the circuit board.

[0048] The internal wiring 16 is provided in a via that penetrates the upper surface 111a and the lower surface 111b of the first member 11. The via in which the internal wiring 16 is provided is provided outside the through-hole 112. The upper end (the end on the +Z direction side) of the internal wiring 16 is joined to the lower surface (the surface on the -Z direction side) of the first terminal 14. The lower end (the end on the -Z direction side) of the internal wiring 16 is joined to the upper surface (the surface on the +Z direction side) of the second terminal 15. The first terminal 14 and the second terminal 15 are electrically connected via the internal wiring 16. That is, the third terminal 221 of the wiring board 22 is electrically connected to an external power supply via the first terminal 14, the second terminal 15, the internal wiring 16, and wiring provided on the upper surface of the circuit board. When the light source unit 20 emits light, power from the external power supply is supplied to the light source unit 20 through the first terminal 14, the second terminal 15, the internal wiring 16, and the third terminal 221.

[0049] Examples of materials that can be used to form the first terminal 14, the second terminal 15, and the internal wiring 16 include gold, silver, copper, nickel, palladium, and aluminum, but the materials that can be used to form the first terminal 14, the second terminal 15, and the internal wiring 16 are not limited to these.

[0050] The metal film 17a is provided on the upper surface 121a of the second member 12. By joining the upper surface 121a of the second member 12 and the lower surface (the surface on the −Z direction side) of the joining member 30 facing the upper surface 121a of the second member 12 via the metal film 17a, it is possible to improve the adhesion between the second member 12 and the joining member 30. In particular, because the second member 12 contains graphite, it is preferable to join the upper surface 121a of the second member 12 and the lower surface of the joining member 30 via the metal film 17a.

[0051] Metal film 17b is provided on the lower surface 121b of the second member 12. By joining the lower surface 121b of the second member 12 and the upper surface of the circuit board facing the lower surface 121b of the second member 12 via metal film 17b, it is possible to improve the adhesion between the second member 12 and the circuit board. In particular, because the second member 12 contains graphite, it is preferable to join the lower surface 121b of the second member 12 and the lower surface of the circuit board via metal film 17b.

[0052] Examples of materials that can be used to form the metal films 17a and 17b include gold, silver, copper, nickel, palladium, and aluminum, but are not limited to these.

[0053] <Light Source Unit 20> Next, the configuration of the light source unit 20 will be described. The light source unit 20 is disposed above the substrate 10. More specifically, the light source unit 20 is disposed above the second member 12 of the substrate 10, with the metal film 17a and the bonding member 30 sandwiched between them. The light source unit 20 emits white light. However, the light emitted by the light source unit 20 is not limited to white light, and may be light having a specific wavelength, such as blue. Furthermore, the wavelength and chromaticity of the light emitted by the light source unit 20 may be selected appropriately depending on the intended use of the light emitting device 1.

[0054] As shown in Fig. 1, the light source unit 20 has a substantially rectangular outer shape when viewed from above. However, the light source unit 20 may have other outer shapes, such as a substantially circular, elliptical, or polygonal shape when viewed from above. As shown in Fig. 2, the light source unit 20 includes a light-emitting element 21 and a wiring substrate 22. The light source unit 20 further includes a light-shielding member 23 and a wavelength conversion member 24.

[0055] The light source unit 20 includes a plurality of light-emitting elements 21 arranged in a matrix along the XY plane. Each of the light-emitting elements 21 is a semiconductor light-emitting element such as an LED (Light Emitting Diode) or an LD (Laser Diode). The light-emitting element 21 includes an n-type semiconductor layer, an active layer, and a p-type semiconductor layer that are stacked in this order in the Z-axis direction. The light-emitting element 21 emits, for example, blue light. Each of the n-type semiconductor layer, the active layer, and the p-type semiconductor layer in the light-emitting element 21 is made of, for example, In Ｘ Al Ｙ Ga １－Ｘ－Ｙ It is made of a nitride-based semiconductor such as N (0≦X, 0≦Y, X+Y≦1).

[0056] The lower surface (surface on the −Z direction side) of the light-emitting element 21 is joined to wiring provided on the upper surface (surface on the +Z direction side) of the wiring substrate 22, for example, via a pair of positive and negative electrodes. The wiring provided on the upper surface of the wiring substrate 22 is electrically connected to the third terminal 221. As a result, power from an external power source is supplied to the light-emitting element 21 via the first terminal 14, the second terminal 15, and the internal wiring 16 of the substrate 10, the third terminal 221 and wiring provided on the upper surface of the wiring substrate 22, and the pair of positive and negative electrodes.

[0057] From the viewpoints of luminous efficiency and excitation of the wavelength conversion substance, the emission peak wavelength of the light-emitting element 21 is preferably 400 nm or more and 530 nm or less, more preferably 420 nm or more and 490 nm or less, and even more preferably 450 nm or more and 475 nm or less, but the emission peak wavelength of the light-emitting element 21 is not limited thereto.

[0058] As shown in FIG. 2 , the light-shielding member 23 is disposed between adjacent light-emitting elements 21. As a result, the light-shielding member 23 covers the side surfaces of each light-emitting element 21. The light-shielding member 23 is preferably made of a resin material containing a light-reflecting substance in order to improve the light extraction efficiency of the light source unit 20. Examples of the light-reflecting substance include titanium oxide, zinc oxide, magnesium oxide, magnesium carbonate, magnesium hydroxide, calcium carbonate, calcium hydroxide, calcium silicate, magnesium silicate, barium titanate, barium sulfate, aluminum hydroxide, aluminum oxide, zirconium oxide, and silicon oxide. Examples of the resin material include resin materials whose main component is a thermosetting resin, such as epoxy resin, epoxy-modified resin, silicone resin, silicone-modified resin, or phenolic resin.

[0059] The wavelength conversion member 24 is a member that covers the upper surfaces of the plurality of light emitting elements 21. The wavelength conversion member 24 has a substantially rectangular outer shape when viewed from above. However, the wavelength conversion member 24 may have other outer shapes such as a substantially circular, elliptical, or polygonal shape.

[0060] The upper surface (surface on the +Z direction side) of the wavelength conversion member 24 corresponds to the light extraction surface of the light source unit 20. The wavelength conversion member 24 converts the wavelength of light emitted by the light emitting element 21. The wavelength conversion member 24 includes a base material containing a light-transmitting material and a wavelength conversion material. Here, "light-transmitting" means that 60% or more of the light emitted by the light emitting element 21 is transmitted. Examples of light-transmitting materials include resin materials, ceramics, and glass. Examples of resin materials include silicone resins, silicone-modified resins, epoxy resins, epoxy-modified resins, and phenolic resins. Silicone resins or modified resins thereof, which have excellent light resistance and heat resistance, are particularly preferred. However, the light-transmitting material is not limited to these.

[0061] The wavelength conversion material includes a cerium-activated yttrium aluminum garnet (YAG) phosphor. A part of the blue light emitted from the light emitting element 21 is converted into yellow light by the YAG phosphor. As a result, white light is extracted from the light extraction surface of the light source unit 20. However, the wavelength conversion material is not limited to this. Other examples of wavelength conversion materials include cerium-activated lutetium aluminum garnet (LAG), europium- and / or chromium-activated nitrogen-containing calcium aluminosilicate (CaO-Al ２ O ３ -SiO ２ ), europium activated silicate ((Sr,Ba) ２ SiO ４ ), α-sialon phosphor, β-sialon phosphor, etc. The wavelength conversion substance may be dispersed in the substrate or provided on the substrate.

[0062] The wiring substrate 22 is a silicon substrate that includes an integrated circuit for controlling the light emitting operation of the plurality of light emitting elements 21. However, the wiring substrate 22 is not limited to a silicon substrate. The wiring substrate 22 may be a semiconductor substrate other than silicon, a ceramic substrate, a resin substrate, or the like.

[0063] An example of the integrated circuit included in the wiring board 22 is an electronic circuit such as an ASIC (Application Specific Integrated Circuit). The integrated circuit is electrically connected to the wiring provided on the upper surface of the wiring board 22 and the third terminal 221.

[0064] 1 and 2, the bonding member 30 is disposed between the substrate 10 and the light source unit 20. More specifically, the upper surface (the surface on the +Z direction side) of the bonding member 30 is bonded to the lower surface of the wiring substrate 22. The lower surface (the surface on the −Z direction side) of the bonding member 30 is bonded to the upper surface (the surface on the +Z direction side) of the metal film 17a.

[0065] Examples of materials that can be used to form the joining members 30 include metals such as gold, silver, copper, tin, and aluminum, as well as alloys such as gold-tin. However, the materials that can be used to form the joining members 30 are not limited to these.

[0066] 1 and 2 , the covering member 40 is a light-blocking member that is disposed outside the outermost light-emitting element 21 among the plurality of light-emitting elements 21. The covering member 40 also covers the thin conductor wires 50 and the like. The covering member 40 has a frame-like shape that surrounds the plurality of light-emitting elements 21 when viewed from above. However, the covering member 40 may have a shape other than a frame when viewed from above.

[0067] An example of the covering member 40 is a resin containing a filler with light-blocking properties. Examples of resins include silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, and acrylic resin. Examples of fillers with light-blocking properties include light-absorbing substances such as pigments, carbon black, titanium black, and graphite, and light-reflecting substances such as titanium oxide, aluminum oxide, zinc oxide, barium carbonate, barium sulfate, boron nitride, aluminum nitride, and glass filler. The exterior color of the covering member 40 may be white, which has excellent light reflectivity, black, which has excellent light absorption, or gray, which has both light reflectivity and light absorption properties. From the viewpoint of suppressing deterioration of the resin due to light absorption, it is preferable that the outermost surface of the covering member 40 be a white resin with light reflectivity.

[0068] [Modification 1 of First Embodiment] Next, a light emitting device 1A according to Modification 1 of the first embodiment will be described with reference to Fig. 3. Fig. 3 is a schematic cross-sectional view of the light emitting device 1A according to Modification 1 of the first embodiment, cut along the YZ plane.

[0069] 3, the light emitting device 1A includes a substrate 10A and a light source unit 20. The light emitting device 1A further includes a bonding member 30 and a covering member 40. Note that the light source unit 20, the bonding member 30, and the covering member 40 of the light emitting device 1A are the same as those in the first embodiment, and therefore description thereof will be omitted.

[0070] The substrate 10A includes a first member 11A, a second member 12A, and an adhesive member 13A. Similarly to the first embodiment, the substrate 10A further includes a first terminal 14, a second terminal 15, internal wiring 16, and metal films 17a and 17b.

[0071] In the substrate 10A, the thickness of the second member 12A is smaller than the thickness of the first member 11A. Since the light source unit 20 is disposed above the second member 12A, the small thickness of the second member 12A allows the height position (position in the +Z direction) of the light extraction surface of the light source unit 20 to be lowered. This allows the light emitting device 1A to be made smaller.

[0072] The height position of the upper surface 121a1 of the second member 12A is lower than the height position of the upper surface 111a1 of the first member 11A. This allows the first terminal 14 provided on the upper surface 111a1 of the first member 11A to be closer to the third terminal 221 provided on the upper surface of the wiring substrate 22. As a result, the connection reliability of the thin conductor wire 50 connecting the first terminal 14 and the third terminal 221 can be improved. Other effects achieved by the light emitting device 1A are similar to those of the first embodiment.

[0073] Second Embodiment Next, a light emitting device 1B according to a second embodiment will be described with reference to Fig. 4. Fig. 4 is a schematic cross-sectional view of the light emitting device 1B according to the second embodiment taken along the YZ plane.

[0074] The light emitting device 1B includes a substrate 10B and a light source unit 20. The light emitting device 1B further includes a bonding member 30 and a covering member 40. Note that the light source unit 20, the bonding member 30, and the covering member 40 of the light emitting device 1B are the same as those in the first embodiment, and therefore description thereof will be omitted.

[0075] The substrate 10B includes a first member 11B, a second member 12B, and an adhesive member 13B. Similarly to the first embodiment, the substrate 10B further includes a first terminal 14, a second terminal 15, internal wiring 16, and metal films 17a and 17b.

[0076] As shown in FIG. 4 , the shape of the surface 111d2 defining the through-hole 112B in the first member 11B differs from that in the first embodiment. More specifically, the surface 111d2 defining the through-hole 112B has a shape in which the width of the through-hole 112B narrows toward the lower surface 111b2 of the first member 11B. This narrows the gap between the lower surface 111b2 of the first member 11B and the lower surface 121b2 of the second member 12B. As a result, the adhesive member 13B disposed between the first member 11B and the second member 12B can be prevented from leaking out of the gap between the lower surface 111b2 of the first member 11B and the lower surface 121b2 of the second member 12B. Other effects of the light-emitting device 1B are similar to those of the first embodiment.

[0077] Note that a shape in which the width of the through hole 112B narrows toward the lower surface 111b2 of the first member 11B, such as the surface 111d2 that defines the through hole 112B, will hereinafter be referred to as a "tapered shape tapering downward (toward the -Z direction)." The same applies to each of the modified examples of the second embodiment that will be described separately with reference to FIGS. 5 to 7.

[0078] The surface 111d2 defining the through hole 112B may have a shape in which the width of the through hole 112B increases toward the lower surface 111b2 of the first member 11B. For example, if the adhesive member 13B contains a substance with excellent thermal conductivity, such as a conductive paste material, the width of the heat transfer path can increase toward the lower surface 111b2 of the first member 11B. This improves the heat dissipation performance of the substrate 10B.

[0079] [Modification 1 of Second Embodiment] Next, a light emitting device 1C according to Modification 1 of the second embodiment will be described with reference to Fig. 5. Fig. 5 is a schematic cross-sectional view of light emitting device 1C according to Modification 1 of the second embodiment taken along the YZ plane.

[0080] The light emitting device 1C includes a substrate 10C and a light source unit 20. The light emitting device 1C further includes a joining member 30 and a covering member 40. Note that the light source unit 20, the joining member 30, and the covering member 40 of the light emitting device 1C are similar to those in the first and second embodiments, and therefore description thereof will be omitted.

[0081] The substrate 10C includes a first member 11C, a second member 12C, and an adhesive member 13C. Similarly to the first embodiment, the substrate 10C further includes a first terminal 14, a second terminal 15, internal wiring 16, and metal films 17a and 17b.

[0082] In the first member 11C, the surface 111d3 defining the through hole 112C has a tapered shape that narrows downward. This prevents the adhesive member 13C disposed between the first member 11C and the second member 12C from leaking out from the gap between the lower surface 111b3 of the first member 11C and the lower surface 121b3 of the second member 12C. The surface 111d3 defining the through hole 112C may have a shape such that the width of the through hole 112C increases toward the lower surface 111b3 of the first member 11C.

[0083] The thickness of the second member 12C is smaller than the thickness of the first member 11C. This allows the light emitting device 1C to be miniaturized. Furthermore, because the height position of the upper surface 121a3 of the second member 12C is lower than the height position of the upper surface 111a3 of the first member 11C, the first terminal 14 provided on the upper surface 111a3 of the first member 11C and the third terminal 221 provided on the upper surface of the wiring substrate 22 can be brought closer together. As a result, the connection reliability of the thin conductor wire 50 connecting the first terminal 14 and the third terminal 221 can be improved. Other effects achieved by the light emitting device 1C are similar to those of the first and second embodiments.

[0084] [Modification 2 of Second Embodiment] Next, a light emitting device 1D according to Modification 2 of the second embodiment will be described with reference to Fig. 6A and Fig. 6B. Fig. 6A is a schematic cross-sectional view of the light emitting device 1D according to Modification 2 of the second embodiment taken along the YZ plane. Fig. 6B is an enlarged cross-sectional view of a portion of region VIB shown in Fig. 6A.

[0085] The light emitting device 1D includes a substrate 10D and a light source unit 20. The light emitting device 1D further includes a bonding member 30 and a covering member 40. Note that the light source unit 20, the bonding member 30, and the covering member 40 of the light emitting device 1D are similar to those in the first and second embodiments, and therefore description thereof will be omitted.

[0086] The substrate 10D includes a first member 11D, a second member 12D, and an adhesive member 13D. Similarly to the first embodiment, the substrate 10D further includes a first terminal 14, a second terminal 15, internal wiring 16, and metal films 17a and 17b.

[0087] In the second member 12D, the surface 121c4 located on the outer periphery of the second member 12D has a shape in which the width of the second member 12D narrows toward the lower surface 121b4 of the second member 12D. In other words, the surface 121c4 located on the outer periphery of the second member 12D has a tapered shape that narrows downward. This prevents the second member 12D from moving downward (in the -Z direction) by the adhesive member 13D. As a result, it is possible to prevent the second member 12D from detaching from the first member 11D.

[0088] The surface 121c4 located on the outer periphery of the second member 12D may have a shape such that the width of the second member 12D increases toward the lower surface 121b4 of the second member 12D. This allows the width of the heat transfer path to increase toward the lower surface 121b4 of the second member 12D, thereby improving the heat dissipation performance of the second member 12D.

[0089] Furthermore, in the first member 11D, the surface 111d4 defining the through hole 112D also preferably has a tapered shape that narrows downward. As shown in FIG. 6B , in a cross-sectional view, the angle θ1 formed between the lower surface 111b4 of the first member 11D and the surface 111d4 defining the through hole 112D is preferably smaller than the angle θ2 formed between the lower surface 111b4 of the first member 11D and a surface 121c4 located on the outer periphery of the second member 12D. Here, the angle θ1 corresponds to the acute angle formed between the line L1 corresponding to the lower surface 111b4 of the first member 11D and the line L2 corresponding to the surface 111d4 defining the through hole 112D in a cross-sectional view. In other words, the angle θ1 indicates the slope of the taper of the through hole 112D. The angle θ2 is an acute angle between a line L1 corresponding to the lower surface 111b4 of the first member 11D and a line L3 corresponding to the surface 121c4 located on the outer periphery of the second member 12D in a cross-sectional view. That is, the angle θ2 indicates the inclination gradient of the taper of the second member 12D.

[0090] Because the angle θ1 is smaller than the angle θ2, the gap between the lower surface 111b4 of the first member 11D and the lower surface 121b4 of the second member 12D is narrowed, and the adhesive member 13D can be filled into substantially the entire airspace between the first member 11D and the second member 12D. This makes it possible to prevent the adhesive member 13D from leaking out of the gap between the lower surface 111b4 of the first member 11D and the lower surface 121b4 of the second member 12D, and further prevents the second member 12D from detaching from the first member 11D.

[0091] However, angle θ1 may be substantially the same as angle θ2. In this case, no air space is created between the first member 11D and the second member 12D, and the second member 12D fits into the through-hole 112D. This causes the surface 111d4 defining the through-hole 112D of the first member 11D and the surface 121c4 located on the outer periphery of the second member 12D to come into contact with each other. As a result, the first member 11D supports the second member 12D, and therefore, even without providing an adhesive member 13D between the first member 11D and the second member 12D, the second member 12D can be prevented from detaching from the first member 11D. In other words, the configuration of the substrate 10D can be simplified while preventing the second member 12D from detaching from the first member 11D.

[0092] The surface 111d4 defining the through hole 112D may have a shape such that the width of the through hole 112D increases toward the lower surface 111b4 of the first member 11D.

[0093] The surface 111d4 defining the through hole 112D of the first member 11D may be formed along the Z-axis direction, for example, as in the first embodiment. Even in this case, downward movement of the second member 12D is suppressed by the adhesive member 13D. As a result, it is possible to suppress the second member 12D from detaching from the first member 11D. Other effects achieved by the light-emitting device 1D are similar to those of the first and second embodiments.

[0094] [Modification 3 of Second Embodiment] Next, a light emitting device 1E according to Modification 3 of the second embodiment will be described with reference to Fig. 7. Fig. 7 is a schematic cross-sectional view of the light emitting device 1E according to Modification 3 of the second embodiment taken along the YZ plane.

[0095] The light emitting device 1E includes a substrate 10E and a light source unit 20. The light emitting device 1E further includes a bonding member 30 and a covering member 40. Note that the light source unit 20, the bonding member 30, and the covering member 40 of the light emitting device 1E are similar to those in the first and second embodiments, and therefore description thereof will be omitted.

[0096] The substrate 10E includes a first member 11E, a second member 12E, and an adhesive member 13E. Similarly to the first embodiment, the substrate 10E further includes a first terminal 14, a second terminal 15, internal wiring 16, and metal films 17a and 17b.

[0097] In the second member 12E, the surface 121c5 located on the outer periphery of the second member 12E has a tapered shape that narrows downward. This allows the adhesive member 13E to suppress downward movement of the second member 12E. As a result, it is possible to suppress the second member 12E from detaching from the first member 11E. Furthermore, the surface 121c5 located on the outer periphery of the second member 12E may have a shape in which the width of the second member 12E increases toward the lower surface 121b5 of the second member 12E.

[0098] Furthermore, in the first member 11E, the surface 111d5 defining the through hole 112E preferably has a tapered shape that narrows downward. This prevents the adhesive member 13E disposed between the first member 11E and the second member 12E from leaking out from the gap between the lower surface 111b5 of the first member 11E and the lower surface 121b5 of the second member 12E. The surface 111d5 defining the through hole 112E may have a shape in which the width of the through hole 112E increases toward the lower surface 111b5 of the first member 11E. However, the surface 111d5 defining the through hole 112E of the first member 11E may be formed, for example, along the Z-axis direction.

[0099] The thickness of the second member 12E is smaller than the thickness of the first member 11E. This allows the light emitting device 1E to be miniaturized. Furthermore, because the height position of the upper surface 121a5 of the second member 12E is lower than the height position of the upper surface 111a5 of the first member 11E, the first terminal 14 provided on the upper surface 111a5 of the first member 11E and the third terminal 221 provided on the upper surface of the wiring substrate 22 can be brought closer together. As a result, the connection reliability of the thin conductor wire 50 connecting the first terminal 14 and the third terminal 221 can be improved. Other effects achieved by the light emitting device 1E are similar to those of the first and second embodiments.

[0100] [Method of Manufacturing Light-Emitting Device According to Embodiment] Next, a method of manufacturing a light-emitting device according to an embodiment will be described. As an example, a method of manufacturing the light-emitting device 1 according to the first embodiment will be described with reference to Figs. 8A to 10B. Figs. 8A to 8D are schematic cross-sectional views for explaining each step included in a method of manufacturing the substrate 10 in the light-emitting device 1. Figs. 9A to 9E are schematic cross-sectional views for explaining an example of a method of producing the second member 12. Figs. 10A and 10B are schematic cross-sectional views for explaining each step included in the method of manufacturing the light-emitting device 1.

[0101] <Method of Manufacturing Substrate 10> First, a method of manufacturing the substrate 10 will be described as a premise for explaining a method of manufacturing the light emitting device 1. As shown in Fig. 8A, a plate-like member 11P extending in the XY plane is prepared. Note that the first terminals 14, the second terminals 15, and the internal wiring 16 may be provided on the upper surface 111a, the lower surface 111b, and the interior of the plate-like member 11P, respectively.

[0102] 8B , through-holes 112 are formed in the central region of the plate-shaped member 11P, penetrating from the upper surface 111a to the lower surface 111b of the plate-shaped member 11P. By forming the through-holes 112 in the plate-shaped member 11P, a first member 11 having a frame-like shape in top view is obtained.

[0103] Examples of methods for forming the through hole 112 include drilling, punching, and laser processing. However, the method for forming the through hole 112 is not limited to these. In the drilling method, if a cutting tool with an inclined blade, such as a router bit, is used, the surface 111d defining the through hole 112 can be machined into a tapered shape that tapers downward. In the punching method, if a mold in which the distance between two dies supporting the plate-like member 11P is wider than the width of the punch is used, the surface 111d defining the through hole 112 can be machined into a tapered shape that tapers downward.

[0104] 8C , the second member 12 is placed inside the through-hole 112 of the first member 11. Before placing the second member 12 inside the through-hole 112, it is preferable to attach a support tape 70 that covers the lower side (−Z direction side) of the through-hole 112. By attaching the support tape 70 in advance, the second member 12 can be fixed in a desired position.

[0105] Here, for example, a method for producing the second member 12 is as follows. An example of a method for producing the second member 12 will be described with reference to FIGS. 9A to 9E . First, as shown in FIG. 9A , a first layer 126L1 corresponding to the third region 126 of the second member 12, a second layer 125L1 corresponding to the second region 125, a third layer 124L corresponding to the first region 124, a fourth layer 125L2 corresponding to the second region 125, and a fifth layer 126L2 corresponding to the third region 126 are stacked in this order from the bottom of the heat-resistant container 90. At this time, each time each layer is stacked in the heat-resistant container 90, the stacked layers may be pressurized.

[0106] Here, the second layer 125L1, the third layer 124L, and the fourth layer 125L2 contain, for example, flake-shaped graphite having a particle size of 10 μm to 700 μm or substantially spherical graphite having a particle size of 8 μm to 40 μm. When the first layer 126L1 and the fifth layer 126L2 contain graphite, the graphite contained in the first layer 126L1 and the fifth layer 126L2 may be, for example, flake-shaped graphite having a particle size of 10 μm to 700 μm or substantially spherical graphite having a particle size of 8 μm to 40 μm.

[0107] The first layer 126L1 and the fifth layer 126L2 may contain a powdered thermally conductive material such as a substantially spherical metal powder or ceramic powder having a particle size of 1.4 μm to 20 μm. Similarly, the second layer 125L1 and the fourth layer 125L2 may contain a powdered thermally conductive material such as a substantially spherical metal powder or ceramic powder having a particle size of 1.4 μm to 20 μm.

[0108] The laminate 12L, in which the first to fifth layers are stacked, is placed in a heat-resistant container 90, and the heat-resistant container 90 is then placed in a sintering device to sinter the laminate 12L. At this time, the laminate 12L is preferably sintered while being pressurized in the stacking direction in which the layers of the laminate 12L are stacked. For example, the laminate 12L is subjected to electric sintering while being heated and pressurized at a temperature of 500°C to 900°C and a pressure of 10 MPa to 90 MPa. However, the method for sintering the laminate 12L is not limited to this.

[0109] After sintering, the laminate 12L is removed from the heat-resistant container 90. Next, using a cutting device such as a wire saw or a disc saw, the laminate 12L is cut along the stacking direction to separate it into multiple small pieces. Finally, as shown in FIG. 9B , both ends of each small piece (the ends of the first layer 126L1 and the fifth layer 126L2) are diced and the surfaces are smoothed. This results in the second member 12, as shown in FIG. 9C . If both ends of the small pieces are cut obliquely during dicing, as shown in FIG. 9D , the surface 121c located on the outer periphery of the second member 12 can be tapered downward, as shown in FIG. 9E . This allows, for example, the second member 12D of Variation 2 of the second embodiment to be obtained. The surface roughness of the cut surface of the obtained second member 12 varies depending on the material constituting the second member 12, the volume fraction of the material, the sintering conditions, etc., but is preferably about 1.0 μm to 15.0 μm in arithmetic mean roughness (Sz). The surface roughness of the second member 12 can be adjusted appropriately to match the adhesive member 13. Methods for adjusting the surface roughness include a method of adjusting the material constituting the second member 12, the volume fraction of the material, the sintering conditions, etc., and a method of adjusting the processing conditions when cutting the laminate 12L.

[0110] 8C , a metal film 17a is formed on the upper surface 121a of the obtained second member 12. A metal film 17b is formed on the lower surface 121b of the second member 12. Examples of methods for forming the metal films 17a and 17b include wet processes such as plating, inkjet printing, spin coating, and dipping, and dry processes such as vacuum deposition and sputtering. Thereafter, the second member 12 is placed on the upper surface (the surface on the +Z direction side) of the support tape 70. The metal films 17a and 17b may be formed after the second member 12 is fixed to the first member 11.

[0111] Next, as shown in FIG. 8D , for example, an adhesive resin paste is filled between the first member 11 and the second member 12. Examples of methods for filling the paste include a dispensing method, a screen printing method, and an inkjet method. After filling, the adhesive resin paste is hardened. This forms an adhesive member 13 between the first member 11 and the second member 12. The adhesive member 13 may be formed of a metal material by plating. The adhesive member 13 fixes the second member 12 to the inside of the through hole 112 of the first member 11. Next, the support tape 70 is peeled off from the first member 11 and the second member 12. Through these steps, the substrate 10 is manufactured.

[0112] <Method of Manufacturing Light-Emitting Device 1> Next, a method of manufacturing the light-emitting device 1 will be described. As shown in Fig. 10A, a bonding member 30 containing, for example, silver is formed on the upper surface of the metal film 17a. Methods for forming the bonding member 30 include processes such as a screen printing method, a dispensing method, an inkjet method, a vacuum deposition method, and a sputtering method.

[0113] 10B , the light source unit 20 including the light-emitting element 21 and the wiring board 22 is placed on the bonding member 30, and then heat treatment is performed using a reflow oven or the like to fix the light source unit 20 to the bonding member 30. Furthermore, the thin conductor wires 50 are wired, for example, by wire bonding, to connect the first terminals 14 provided on the upper surface 111a of the first member 11 to the third terminals 221 of the wiring board 22. Furthermore, the covering member 40 is formed to cover the thin conductor wires 50. The covering member 40 is obtained, for example, by supplying uncured white resin to the area overlapping the thin conductor wires 50 in a top view and then curing the white resin. Through these steps, the light-emitting device 1 is manufactured. The obtained light-emitting device 1 is mounted on a circuit board or the like for use.

[0114] The same manufacturing method can be applied to the first modified example of the first embodiment, the second embodiment, and each modified example of the second embodiment.

[0115] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0116] Aspects of the present disclosure are as follows, for example: <Item 1> A substrate comprising: a first member having a through hole extending from an upper surface to a lower surface; and a second member disposed inside the through hole, wherein the second member comprises: a first region containing graphite; a second region disposed outside the first region in a top view, the second region including graphite and a thermally conductive material containing at least one of a metal and a ceramic, the second region having a lower volume fraction of the graphite than the volume fraction of the graphite in the first region; and a third region disposed outside the second region in a top view, the third region including a thermally conductive material containing at least one of a metal and a ceramic, the third region having a higher volume fraction of the thermally conductive material than the volume fraction of the thermally conductive material in the second region. <Item 2> The substrate according to <Item 1>, wherein the first region further includes a thermally conductive material containing at least one of a metal and a ceramic. <Item 3> The substrate according to <Item 1> or <Item 2>, wherein a volume fraction of the graphite in the first region is 70 vol% or more and 100 vol% or less, and a volume fraction of the graphite in the second region is 30 vol% or more and 70 vol% or less. <Item 4> The substrate according to <Item 2>, wherein the thermally conductive material in the first region, the thermally conductive material in the second region, and the thermally conductive material in the third region each contain at least one of copper and aluminum. <Item 5> The substrate according to any one of <Item 1> to <Item 4>, further comprising an adhesive member disposed between the first member and the second member and fixing the second member to the inside of the through hole, and wherein a surface defining the through hole has a shape in which the width of the through hole narrows toward the underside of the first member. <Item 6> The substrate according to any one of <Item 1> to <Item 4>, further comprising an adhesive member disposed between the first member and the second member and fixing the second member to the inside of the through hole, wherein a surface located on the outer periphery of the second member has a shape in which the width of the second member narrows toward a lower surface of the second member.<Item 7> The substrate according to any one of <Item 1> to <Item 4>, further comprising an adhesive member disposed between the first member and the second member and fixing the second member to the inside of the through hole, wherein the surface defining the through hole has a shape in which the width of the through hole narrows toward a lower surface of the first member, and the surface located on the outer periphery of the second member has a shape in which the width of the second member narrows toward the lower surface of the second member, and in a cross-sectional view, an angle formed between the lower surface of the first member and the surface defining the through hole is smaller than an angle formed between the lower surface of the first member and the surface located on the outer periphery of the second member. <Item 8> The substrate according to any one of <Item 1> to <Item 7>, wherein a thickness of the second member is smaller than a thickness of the first member, and a position of an upper surface of the second member is lower than a position of an upper surface of the first member. <Item 9> The substrate according to any one of <Item 1> to <Item 8>, wherein a metal film is disposed on each of an upper surface and a lower surface of the second member. <Item 10> A light-emitting device comprising: a substrate; and a light source unit disposed above the substrate, wherein the substrate comprises: a first member having a through hole penetrating from an upper surface to a lower surface; and a second member disposed inside the through hole, wherein the second member comprises: a first region including graphite and disposed at a position overlapping with the light source unit in a top view; a second region disposed outside the first region in a top view, the second region including graphite and a thermally conductive material containing at least one of a metal and a ceramic, the second region having a volume fraction lower than the volume fraction of the graphite in the first region; and a third region disposed outside the second region in a top view, the third region including a thermally conductive material containing at least one of a metal and a ceramic, the third region having a volume fraction higher than the volume fraction of the thermally conductive material in the second region.

[0117] This application claims priority based on Japanese Patent Application No. 2023-153916 filed with the Japan Patent Office on September 20, 2023, and incorporates by reference all of the contents of the above application.

[0118] 1, 1A, 1B, 1C, 1D, 1E Light emitting device 10, 10A, 10B, 10C, 10D, 10E Substrate 11, 11A, 11B, 11C, 11D, 11E First member 111a, 111a1, 111a2, 111a3, 111a4, 111a5 Top surface 111b, 111b1, 111b2, 111b3, 111b4, 111b5 Lower surface 111d, 111d2, 111d3, 111d4, 111d5 Surface defining the through hole 112, 112B, 112C, 112D, 112E Through hole 12, 12A, 12B, 12C, 12D, 12E Second member 121a, 121a1, 121a3, 121a5 Upper surface 121b, 121b2, 121b3, 121b4, 121b5 Lower surface 121c, 121c4, 121c5 Surface located on the outer periphery of the second member 124 First region 125 Second region 126 Third region 13, 13A, 13B, 13C, 13D, 13E Adhesive member 14 First terminal 15 Second terminal 16 Internal wiring 17a, 17b Metal film 20 Light source section 21 Light-emitting element 22 Wiring substrate 23 Light-shielding member 24 Wavelength conversion member 30 Joining member 40 Covering member 50 Thin conductor wire

Claims

1. A substrate comprising: a first member having a through hole extending from a top surface to a bottom surface; and a second member disposed inside the through hole, wherein the second member comprises: a first region including graphite; a second region disposed outside the first region in a top view, the second region including graphite and a thermally conductive material containing at least one of a metal and a ceramic, the volume fraction of the graphite being lower than the volume fraction of the graphite in the first region; and a third region disposed outside the second region in a top view, the third region including a thermally conductive material containing at least one of a metal and a ceramic, the volume fraction of the thermally conductive material being higher than the volume fraction of the thermally conductive material in the second region.

2. The substrate of claim 1, wherein the first region further comprises a thermally conductive material containing at least one of a metal and a ceramic.

3. The substrate according to claim 1 or 2, wherein the volume fraction of the graphite in the first region is 70 vol% or more and 100 vol% or less, and the volume fraction of the graphite in the second region is 30 vol% or more and 70 vol% or less.

4. The substrate of claim 2, wherein each of the thermally conductive material in the first region, the thermally conductive material in the second region, and the thermally conductive material in the third region includes at least one of copper and aluminum.

5. A substrate as described in any one of claims 1 to 4, further comprising an adhesive member disposed between the first member and the second member and fixing the second member to the inside of the through hole, wherein the surface defining the through hole has a shape in which the width of the through hole narrows toward the underside of the first member.

6. A substrate as described in any one of claims 1 to 4, further comprising an adhesive member disposed between the first member and the second member and fixing the second member to the inside of the through hole, wherein a surface located on the outer periphery of the second member has a shape in which the width of the second member narrows toward the lower surface of the second member.

7. A substrate as described in any one of claims 1 to 4, further comprising an adhesive member disposed between the first member and the second member and fixing the second member to the inside of the through hole, wherein the surface defining the through hole has a shape in which the width of the through hole narrows toward the underside of the first member, and the surface located on the outer periphery of the second member has a shape in which the width of the second member narrows toward the underside of the second member, and in a cross-sectional view, the angle formed between the underside of the first member and the surface defining the through hole is smaller than the angle formed between the underside of the first member and the surface located on the outer periphery of the second member.

8. A substrate according to any one of claims 1 to 7, wherein the thickness of the second member is smaller than the thickness of the first member, and the position of the upper surface of the second member is lower than the position of the upper surface of the first member.

9. The substrate according to any one of claims 1 to 8, wherein a metal film is disposed on each of the upper and lower surfaces of the second member.

10. A light-emitting device comprising: a substrate; and a light source unit arranged above the substrate, the substrate comprising: a first member having a through hole extending from a top surface to a bottom surface; and a second member arranged inside the through hole, the second member comprising: a first region including graphite and arranged at a position overlapping with the light source unit in a top view; a second region arranged outside the first region in a top view, the second region including graphite and a thermally conductive material containing at least one of a metal and a ceramic, the volume fraction of the graphite being lower than the volume fraction of the graphite in the first region; and a third region arranged outside the second region in a top view, the third region including a thermally conductive material containing at least one of a metal and a ceramic, the volume fraction of the thermally conductive material being higher than the volume fraction of the thermally conductive material in the second region.

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