Semiconductor light-emitting unit

Abstract

This semiconductor light-emitting unit comprises a semiconductor light-emitting device and a heat-dissipating body that is attached to the semiconductor light-emitting device. The semiconductor light-emitting device is provided with a semiconductor light-emitting element and a cap that covers the semiconductor light-emitting element. The cap has an opening that is open in one direction and a side surface that faces a direction intersecting said one direction. The heat-dissipating body includes a plate-shaped heat-dissipating base part and a cap cover part. The cap cover part is provided standing upright from the heat-dissipating base part, and is connected to the side surface of the cap in a manner allowing transmission of heat, in a state where the opening of the cap faces a direction that intersects the thickness direction of the heat-dissipating base part.

Description

Semiconductor Light Emitting Unit

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to semiconductor light emitting units.

[0002] A known semiconductor light emitting unit includes a circuit board and a semiconductor light emitting device mounted on the circuit board. A known example of such a semiconductor light emitting device is a CAN package (see, for example, Patent Document 1). Such semiconductor light emitting units are widely used as light source devices installed in various electronic devices.

[0003] JP 2016-29718 A

[0004] However, there is room for improvement in terms of heat dissipation of semiconductor light-emitting units.

[0005] A semiconductor light emitting unit that solves the above problem comprises a semiconductor light emitting device and a heat sink to which the semiconductor light emitting device is attached, wherein the semiconductor light emitting device comprises a semiconductor light emitting element, an opening that opens in one direction, and a side surface facing in a direction intersecting the one direction, and a cap that covers the semiconductor light emitting element, and the heat sink includes a plate-shaped heat dissipation base and a cap cover portion that stands up from the heat dissipation base and is connected to the side surface of the cap in a heat transferable manner with the opening surface facing in a direction intersecting the thickness direction of the heat dissipation base.

[0006] According to the semiconductor light emitting unit, heat dissipation can be improved.

[0007] FIG. 1 is a perspective view of a semiconductor light emitting device according to a first embodiment. FIG. 2 is a perspective view of the semiconductor light emitting device of FIG. 1 with a cap removed. FIG. 3 is a cross-sectional view schematically showing the semiconductor light emitting device of FIG. 1. FIG. 4 is a perspective view schematically showing a stem of the semiconductor light emitting device of FIG. 2. FIG. 5 is a perspective view schematically showing the stem as viewed from the opposite side to that of FIG. 4. FIG. 6 is an enlarged view of the switching element and its periphery of FIG. 3. FIG. 7 is a side view schematically showing the semiconductor light emitting device of FIG. 2. FIG. 8 is a cross-sectional view of the semiconductor light emitting device taken along line F8-F8 in FIG. 6. FIG. 9 is a front view of first and second substrates attached to a heat sink of the semiconductor light emitting device. FIG. 10 is a back view of the first and second substrates of FIG. 9. FIG. 11 is a circuit diagram of a laser system including the semiconductor light emitting device of the first embodiment. FIG. 12 is a perspective view schematically showing a perspective structure of a semiconductor light emitting unit including the semiconductor light emitting device. FIG. 13 is a side view of the semiconductor light emitting unit of FIG. 12. FIG. 14 is an enlarged view of the cap cover portion and its periphery in FIG. 13 . FIG. 15 is a perspective view schematically showing the perspective structure of a semiconductor light emitting unit of a comparative example. FIG. 16 is a cross-sectional view of a semiconductor light emitting device of a comparative example. FIG. 17 is a graph showing the results of a thermal conduction analysis of a semiconductor light emitting unit of a comparative example. FIG. 18 is a graph showing the results of a thermal conduction analysis of a semiconductor light emitting unit of the first embodiment. FIG. 19 is a graph showing the results of a thermal conduction analysis of a semiconductor light emitting unit of the first embodiment when the material of the heat sink is changed. FIG. 20 is a graph showing the results of a thermal conduction analysis of a semiconductor light emitting unit of the first embodiment when the volume of the heat sink is changed. FIG. 21 is a graph showing the results of a thermal conduction analysis of a semiconductor light emitting unit including a semiconductor light emitting device of a comparative example. FIG. 22 is a perspective view of a semiconductor light emitting device of a second embodiment with the cap removed from the semiconductor light emitting device. FIG. 23 is an enlarged view of a switching element and its periphery in the semiconductor light emitting device of FIG. 22 . FIG. 24 is a front view of a first substrate and a second substrate attached to a heat sink of the semiconductor light emitting device. Fig. 25 is a rear view of the first substrate and the second substrate of Fig. 24. Fig. 26 is a perspective view of the semiconductor light emitting device of the third embodiment with the cap removed from the semiconductor light emitting device.FIG. 27 is an enlarged view of a switching element and its periphery in the semiconductor light emitting device of FIG. 26 . FIG. 28 is a front view of a first substrate and a second substrate attached to a heat sink of the semiconductor light emitting device. FIG. 29 is a rear view of the first substrate and the second substrate of FIG. 28 . FIG. 30 is a perspective view of a semiconductor light emitting device of a fourth embodiment with a cap removed from the semiconductor light emitting device. FIG. 31 is a cross-sectional view schematically showing the cross-sectional structures of the heat sink, light emitting unit, and drive unit of the semiconductor light emitting device of FIG. 30 . FIG. 32 is a perspective view of a semiconductor light emitting device of a fifth embodiment with a cap removed from the semiconductor light emitting device. FIG. 33 is a cross-sectional view schematically showing the cross-sectional structures of the heat sink, light emitting unit, and drive unit of the semiconductor light emitting device of FIG. 32 . FIG. 34 is a perspective view of a semiconductor light emitting device of a sixth embodiment with a cap removed from the semiconductor light emitting device. FIG. 35 is a cross-sectional view schematically showing the cross-sectional structures of the heat sink, light emitting unit, and drive unit of the semiconductor light emitting device of FIG. 34 . Fig. 36 is a perspective view of a modified semiconductor light emitting device with the cap removed from the semiconductor light emitting device. Fig. 37 is a side view of a modified semiconductor light emitting unit, showing an enlarged side structure of the cap cover and its surroundings. Fig. 38 is a front view of the semiconductor light emitting unit of Fig. 37, showing an enlarged front structure of the cap cover and its surroundings.

[0008] Hereinafter, several embodiments of semiconductor light emitting devices according to the present disclosure will be described with reference to the accompanying drawings. Note that for simplicity and clarity of description, components shown in the drawings are not necessarily drawn to scale. Also, for ease of understanding, hatching lines may be omitted in cross-sectional views. The accompanying drawings merely illustrate embodiments of the present disclosure and should not be considered as limiting the present disclosure.

[0009] The following detailed description includes devices, systems, and methods embodying exemplary embodiments of the present disclosure. This detailed description is merely illustrative in nature and is not intended to limit the embodiments of the present disclosure or the application and uses of such embodiments.

[0010] <First Embodiment> [Schematic Configuration of Semiconductor Light-Emitting Device] The configuration of a semiconductor light-emitting device 10 according to a first embodiment will be described with reference to Figures 1 to 10. Figure 1 shows a perspective view of the semiconductor light-emitting device 10. Figure 2 shows a perspective view of the semiconductor light-emitting device 10 of Figure 1 with a cap 50, which will be described later, removed.

[0011] 1 can be used in a laser system such as LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging), which is an example of three-dimensional distance measurement. Note that the semiconductor light-emitting device 10 may also be used in a laser system for two-dimensional distance measurement.

[0012] 1 and 2, the semiconductor light-emitting device 10 includes a stem 20, a light-emitting unit 30 and a driving unit 40 attached to the stem 20, and a cap 50 surrounding the light-emitting unit 30 and the driving unit 40. As shown in Fig. 1, the semiconductor light-emitting device 10 is a CAN package type semiconductor laser.

[0013] 2, the stem 20 has a flat base 21, a conductive heat sink 22 standing on the base 21, and a plurality of (four in this embodiment) lead pins 23A to 23D that constitute external terminals. Both the light-emitting unit 30 and the drive unit 40 are attached to the heat sink 22. In the following description of this embodiment, the thickness direction of the base 21 is defined as the z direction, and two mutually orthogonal directions orthogonal to the z direction are defined as the x direction and the y direction.

[0014] 2, the light-emitting unit 30 includes a first substrate 31 and a semiconductor light-emitting element 32 mounted on the first substrate 31. The first substrate 31 is attached to a heat sink 22. In this embodiment, a semiconductor laser is used as the semiconductor light-emitting element 32. Here, in this specification, "mounting" means joining with a conductive bonding material such as solder paste or silver (Ag) paste. In other words, "component A is mounted on component B" means that component A is directly attached to component B with a conductive bonding material.

[0015] The drive unit 40 includes a second substrate 41 and a drive circuit element 42 mounted on the second substrate 41. The second substrate 41 is attached to the heat sink 22 at a position spaced apart from the first substrate 31. More specifically, the second substrate 41 is attached to a portion of the heat sink 22 closer to the base 21 than the first substrate 31. The second substrate 41 is disposed spaced apart in the z-direction from the protrusion 26 of the heat sink 22. Note that an intermediate member different from the second substrate 41 and the heat sink 22 may be interposed between the second substrate 41 and the heat sink 22. In other words, "the second substrate 41 is attached to the heat sink 22" includes both a configuration in which the second substrate 41 is directly attached to the heat sink 22 and a configuration in which the second substrate 41 is indirectly attached to the heat sink 22 via an intermediate member.

[0016] The drive circuit element 42 includes a switching element 43 and a plurality of (four in this embodiment) capacitors 44. The switching element 43 is electrically connected to the four light-emitting units 32A (see FIG. 3) individually by four wires W1. The switching element 43 is electrically connected to the lead pins 23A and 23B individually by wires W2 and W3. The second substrate 41 is electrically connected to the lead pin 23C by a wire W4.

[0017] 3 , the cap 50 covers the heat sink 22, the first substrate 31, the second substrate 41, the semiconductor light-emitting element 32, and the drive circuit element 42. The cap 50 is formed in a cylindrical shape. The cap 50 is made of, for example, a light-shielding material. An example of the light-shielding material is iron (Fe).

[0018] The cap 50 has a top plate portion 52 having an opening 53, and a tube portion 51 having the top plate portion 52 at one end. In this embodiment, the tube portion 51 is cylindrical. The top plate portion 52 covers one end of the tube portion 51 in the z direction. The opening 53 is configured to allow light from the semiconductor light emitting element 32 to pass through the top plate portion 52 and exit. The cap 50 has a light-transmitting plate 54 that closes the opening 53. The light-transmitting plate 54 is a flat plate made of transparent resin or glass. The light-transmitting plate 54 is attached to the inner surface of the top plate portion 52.

[0019] The cap 50 can also be said to have an opening 53 that opens in one direction and a side surface that faces a direction intersecting the one direction. Here, in the example shown in FIGS. 2 and 3 , the one direction in which the opening 53 opens is the z direction. The side surface of the cap 50 is the outer peripheral surface of the tubular portion 51. The outer peripheral surface of the tubular portion 51 faces a direction intersecting the z direction. Therefore, in this embodiment, the direction intersecting the one direction is a direction intersecting the z direction. In this embodiment, the outer peripheral surface of the tubular portion 51 faces a direction perpendicular to the z direction. Note that the directions described here may be changed depending on the arrangement of the semiconductor light-emitting device 10. In other words, if the opening 53 opens in, for example, the y direction instead of the z direction, the one direction is the y direction, and the direction intersecting the one direction is a direction intersecting the y direction.

[0020] In the semiconductor light-emitting device 10, a current is supplied to the semiconductor light-emitting element 32 via the lead pins 23A to 23D and the switching element 43. As a result, the laser light emitted from the semiconductor light-emitting element 32 is directed in the z direction, that is, passes through the opening 53 of the cap 50.

[0021] [Detailed Configuration of Stem] As shown in Figures 4 and 5, the base 21 and the heat sink 22 are integrally formed. Therefore, in this embodiment, the base 21 is also formed from a conductive material. The base 21 and the heat sink 22 are formed from, for example, copper (Cu), a Cu alloy, Fe, an Fe alloy, aluminum (Al), an Al alloy, or the like. The base 21 and the heat sink 22 may be formed separately. In this case, the stem 20 is formed by joining the separately formed base 21 and heat sink 22 together. Furthermore, the material forming the base 21 and the material forming the heat sink 22 may be different from each other.

[0022] The shape of the base 21 when viewed from the z direction is approximately circular. In this embodiment, the diameter of the base 21 is approximately 5.6 mm, and the thickness of the base 21 is approximately 1.2 mm. The base 21 includes a base front surface 21s and a base back surface 21r that face opposite each other in the z direction. In other words, the z direction can also be said to be the thickness direction of the base 21. Note that the diameter and thickness of the base 21 can each be changed as desired.

[0023] The heat sink 22 stands in a direction perpendicular to the base surface 21s of the base 21. That is, the heat sink 22 extends in the thickness direction of the base 21. Therefore, the z direction can be said to be the standing direction of the heat sink 22.

[0024] The heat sink 22 is provided at a position offset in the y direction from the center of the base 21. The heat sink 22 extends in the z direction from the base surface 21s of the base 21. In other words, the z direction can also be said to be the erection direction of the heat sink 22. In this embodiment, the height of the heat sink 22 from the base surface 21s of the base 21 (the size of the heat sink 22 in the z direction) is approximately 4.45 mm.

[0025] The shape of the heat sink 22 when viewed from the z direction is approximately fan-shaped. The surface of the heat sink 22 facing the center of the base 21 is a mounting surface 24 to which the light-emitting unit 30 and the drive unit 40 (both see FIG. 3 ) are attached. The mounting surface 24 includes flat surfaces along the z direction and the x direction.

[0026] The heat sink 22 includes, as mounting surfaces 24, a first mounting surface 24A to which the light-emitting unit 30 is attached and a second mounting surface 24B to which the drive unit 40 is attached. The first mounting surface 24A is formed closer to the tip of the heat sink 22 than the second mounting surface 24B. In this embodiment, the first mounting surface 24A is a surface that is continuous with the tip surface 22a of the heat sink 22. Both the first mounting surface 24A and the second mounting surface 24B are flat surfaces that extend along the xz plane. The second mounting surface 24B is formed at a position closer to the base 21 than the tip of the heat sink 22. The area of ​​the first mounting surface 24A is smaller than the area of ​​the second mounting surface 24B.

[0027] The heat sink 22 also includes a step portion 25 such that the positions of the first mounting surface 24A and the second mounting surface 24B are different from each other in the y direction. In other words, the first mounting surface 24A protrudes relative to the second mounting surface 24B in a thickness direction perpendicular to the vertical direction (z direction) of the heat sink 22. As can be seen from FIG. 4 , the y direction can be considered to be the thickness direction of the heat sink 22. Thus, the tip of the heat sink 22 protrudes toward the center of the base 21 in the y direction relative to a portion of the heat sink 22 closer to the base 21 than the tip of the heat sink 22. The heat sink 22 can be considered to have a protrusion 26 that includes the first mounting surface 24A. The protrusion 26 protrudes in the y direction relative to the second mounting surface 24B.

[0028] A tip end surface 22 a of the heat sink 22, i.e., the end surface of the heat sink 22 farthest from the base 21 in the z direction, is formed into a flat surface perpendicular to the z direction. The shape of the tip end surface 22 a as viewed from the z direction is, for example, an arc shape.

[0029] The base 21 has a plurality of through holes that penetrate the base 21 in the thickness direction (z direction). In this embodiment, the plurality of through holes includes, for example, three through holes 21A, 21B, and 21C. These through holes 21A, 21B, and 21C are located on the opposite side of the heat sink 22 from the center of the base 21 when viewed from the z direction. The shapes of the through holes 21A, 21B, and 21C when viewed from the z direction are, for example, approximately circular. In this embodiment, the diameters of the through holes 21A, 21B, and 21C are equal to one another, for example, approximately 1.0 mm. The shapes and sizes of the through holes 21A, 21B, and 21C when viewed from the z direction can be changed as desired.

[0030] The lead pins 23A, 23B, and 23C penetrate the base 21 in its thickness direction (z direction). More specifically, the lead pin 23A is inserted into the through hole 21A, the lead pin 23B is inserted into the through hole 21B, and the lead pin 23C is inserted into the through hole 21C. An insulating material 27 that insulates the lead pins 23A, 23B, and 23C from the base 21 is filled between the lead pin 23A and the inner circumferential surface of the through hole 21A, between the lead pin 23B and the inner circumferential surface of the through hole 21B, and between the lead pin 23C and the inner circumferential surface of the through hole 21C. The insulating material 27 is formed of, for example, an insulating resin material or glass.

[0031] The lead pins 23A, 23B, and 23C protrude in the z direction from both the base surface 21s and the base back surface 21r of the base 21. The lead pins 23A, 23B, and 23C include connection portions 28A, 28B, and 28C and terminal portions 29A, 29B, and 29C. The connection portions 28A, 28B, and 28C are the portions of the lead pins 23A, 23B, and 23C that protrude in the z direction from the base surface 21s and are electrically connected to the drive circuit element 42 of the drive unit 40 (see FIG. 3 for both). The terminal portions 29A, 29B, and 29C are the portions of the lead pins 23A, 23B, and 23C that protrude in the z direction from the base back surface 21r and constitute external terminals that are electrically connected to a circuit board when the semiconductor light emitting device 10 is mounted on the circuit board.

[0032] 5, the lead pin 23D protrudes in the z direction from the base rear surface 21r of the base 21, but does not protrude in the z direction from the base front surface 21s (see FIG. 4). The lead pin 23D is fixed at a position overlapping the heat sink 22 when viewed from the z direction.

[0033] The lead pin 23D includes a terminal portion 29D. The terminal portion 29D is a portion of the lead pin 23D that protrudes from the base back surface 21r in the z direction and constitutes an external terminal that is electrically connected to a circuit board when the semiconductor light emitting device 10 is mounted on the circuit board. A connection portion 29DA having a larger diameter than the tip of the terminal portion 29D is provided at the end of the terminal portion 29D on the base back surface 21r side of the base 21. The connection portion 29DA is formed, for example, in a flat plate shape. The connection portion 29DA is fixed to the base 21. This electrically connects the lead pin 23D to the base 21. Because the base 21 is electrically connected to the heat sink 22, the lead pin 23D is also electrically connected to the heat sink 22.

[0034] [Configuration of Light-Emitting Unit and Driving Unit] FIG. 6 shows an enlarged front view of the light-emitting unit 30 and driving unit 40 of the semiconductor light-emitting device 10. FIG. 7 shows the side view of the switching element 43 and its surroundings in FIG. 2. FIG. 8 shows the cross-sectional structure of the heat sink 22, light-emitting unit 30, and driving unit 40. FIG. 9 shows the front view of the first substrate 31 and the second substrate 41 attached to the heat sink 22. FIG. 10 shows the rear view of each of the first substrate 31 and the second substrate 41. For ease of understanding, wires W1 to W4 are omitted from FIGS. 7 and 8. For ease of understanding, the semiconductor light-emitting element 32 and the switching element 43 and the multiple capacitors 44, which are the driving circuit elements 42, are indicated by two-dot chain lines in FIG. 10. For convenience, the heat sink 22 is indicated by two-dot chain lines in FIG. 10.

[0035] 6 , the first substrate 31 is attached to the first mounting surface 24A of the heat sink 22. More specifically, the first substrate 31 is joined to the first mounting surface 24A with a conductive bonding material such as solder paste or silver (Ag) paste. In this embodiment, the first substrate 31 is joined to the first mounting surface 24A with Ag paste. When viewed from the y direction, the first substrate 31 is formed in a rectangular shape with the x direction as the longitudinal direction and the z direction as the lateral direction.

[0036] The first substrate 31 is disposed closer to the tip surface 22a of the first mounting surface 24A. More specifically, the center of the first substrate 31 in the z direction is located closer to the tip surface 22a than the center of the first mounting surface 24A in the z direction. The first substrate 31 is disposed at the center of the first mounting surface 24A in the x direction. The length of the first substrate 31 in the x direction is shorter than the length of the first mounting surface 24A in the x direction. In one example, the length of the first substrate 31 in the x direction is shorter than half the length of the first mounting surface 24A in the x direction. In one example, the length of the first substrate 31 in the x direction is shorter than one-third the length of the first mounting surface 24A in the x direction.

[0037] The first substrate 31 has an insulating first base material 31A. The first base material 31A supports the semiconductor light emitting element 32. The first base material 31A is formed in a flat plate shape. The first base material 31A has a high thermal conductivity for heat dissipation from the semiconductor light emitting element 32. In one example, the thermal conductivity of the first base material 31A is higher than the thermal conductivity of a second base material 41A (described later) of the second substrate 41.

[0038] Furthermore, the first base material 31A is formed from a material having a linear expansion coefficient closer to that of the semiconductor light emitting element 32 than that of the heat sink 22. In other words, the difference between the linear expansion coefficient of the first base material 31A and that of the semiconductor light emitting element 32 is smaller than the difference between the linear expansion coefficient of the heat sink 22 and that of the semiconductor light emitting element 32. The first base material 31A is formed from, for example, aluminum nitride, alumina, a copper-tungsten alloy (CuW), copper-aluminum nitride-copper (Cu-AlN-Cu), a copper-diamond alloy, or a silver-diamond alloy. Here, when the heat sink 22 is made of Cu, the linear expansion coefficient of the heat sink 22 is 16.5×10 －６(1 / K), and when the first base material 31A is made of alumina, the linear expansion coefficient of the first substrate 31 is 7.2×10 －６ (1 / K). When the semiconductor light emitting element 32 is made of gallium arsenide (GaAs), the linear expansion coefficient of the semiconductor light emitting element 32 is 5.4×10 －６ (1 / K) In this way, the first base material 31A has a high thermal conductivity and a linear expansion coefficient close to that of the semiconductor light emitting element 32.

[0039] 7, the first substrate 31 includes a first substrate front surface 31s and a first substrate back surface 31r that face opposite each other in the y direction. The first substrate front surface 31s faces the same side as the first mounting surface 24A, and the first substrate back surface 31r faces the first mounting surface 24A. The semiconductor light emitting element 32 is mounted on the first substrate front surface 31s. Here, the first substrate front surface 31s is formed by the substrate front surface of the first base material 31A. The first substrate back surface 31r is formed by the substrate back surface of the first base material 31A.

[0040] The thickness TB1 of the first substrate 31 is thicker than the thickness TL of the semiconductor light emitting element 32. The thickness TB1 of the first substrate 31 is thicker than the thickness TS of the switching element 43. Here, the thickness TL of the semiconductor light emitting element 32 can be defined as the distance in the y direction between an element front surface 32s and an element back surface 32r, which will be described later, of the semiconductor light emitting element 32. The thickness TS of the switching element 43 can be defined as the distance in the y direction between a switching element front surface 43s and a switching element back surface 43r, which will be described later, of the switching element 43.

[0041] The thickness TB1 of the first substrate 31 is, for example, 0.1 mm or more and 0.4 mm or less. The thickness TB1 of the first substrate 31 can be defined as the distance in the y direction between a first substrate front surface 31s and a first substrate back surface 31r of the first substrate 31. The thickness TB2 of the second substrate 41 can be defined as the distance in the y direction between a second substrate front surface 41s (described later) and a second substrate back surface 41r of the second substrate 41.

[0042] The thickness TB1 of the first substrate 31 can be changed as desired. For example, the thickness TB1 of the first substrate 31 may be equal to the thickness TB2 of the second substrate 41. Here, if the difference between the thickness TB1 of the first substrate 31 and the thickness TB2 of the second substrate 41 is, for example, within 10% of the thickness TB1 of the first substrate 31, it can be said that the thickness TB1 of the first substrate 31 is equal to the thickness TB2 of the second substrate 41. For example, the thickness TB1 of the first substrate 31 may be thinner than the thickness TB2 of the second substrate 41. For example, the thickness TB1 of the first substrate 31 may be thicker than the thickness TB2 of the second substrate 41.

[0043] 9 and 10 , the first substrate 31 has surface-side wiring 33s formed on the first substrate surface 31s and back-side wiring 33r formed on the first substrate back surface 31r. The surface-side wiring 33s is formed in a rectangular shape that is slightly smaller than the first substrate surface 31s. The back-side wiring 33r is formed in a rectangular shape that is slightly smaller than the first substrate back surface 31r.

[0044] 8 to 10, the first substrate 31 includes a plurality of (four in this embodiment) through holes 34. Each through hole 34 is formed of a conductive material. In one example, each through hole 34 is formed of a material containing Cu.

[0045] 9 and 10 , the through holes 34 are aligned in a line in the x direction while being aligned with one another in the z direction. That is, the through holes 34 are aligned in a line in the longitudinal direction of the first substrate 31. Each through hole 34 penetrates the first substrate 31 in its thickness direction (y direction). Each through hole 34 is connected to both the front-side wiring 33s and the back-side wiring 33r. As a result, the front-side wiring 33s and the back-side wiring 33r are electrically connected by each through hole 34.

[0046] A heat dissipation material 35 is provided inside each through hole 34. More specifically, the heat dissipation material 35 is provided so as to fill the inside of each through hole 34. The heat dissipation material 35 is formed, for example, from a metal material. In one example, the heat dissipation material 35 is formed from a material containing Cu. In other words, the heat dissipation material 35 may be formed from the same material as the through holes 34. However, the heat dissipation material 35 may be formed from a material different from that of the through holes 34. In one example, the heat dissipation material 35 may be formed from an insulating material.

[0047] As shown in FIG. 8 , the semiconductor light-emitting element 32 is mounted on the surface-side wiring 33s. More specifically, the semiconductor light-emitting element 32 is bonded to the surface-side wiring 33s with a conductive adhesive. As shown in FIG. 6 , the semiconductor light-emitting element 32 includes a plurality of (four in this embodiment) light-emitting units 32A. The plurality of light-emitting units 32A are aligned in a line in the x-direction while being aligned with one another in the z-direction. That is, the plurality of light-emitting units 32A are aligned in a line in the longitudinal direction on the first substrate 31. Here, the output of one light-emitting unit 32A is, for example, 125 W (watts). Therefore, in this embodiment, since the semiconductor light-emitting element 32 has four light-emitting units 32A, the output of the semiconductor light-emitting element 32 is 500 W. In this way, the semiconductor light-emitting element 32 is configured to have a high output in order to improve light intensity.

[0048] The semiconductor light emitting element 32 is formed in a rectangular shape with its longitudinal direction in the x direction and its lateral direction in the z direction when viewed from the y direction. Each light emitting portion 32A is formed in a rectangular shape with its longitudinal direction in the z direction and its lateral direction in the x direction when viewed from the y direction. It can also be said that the multiple light emitting portions 32A are arranged in the longitudinal direction of the semiconductor light emitting element 32.

[0049] 8, the semiconductor light-emitting element 32 has an element front surface 32s and an element back surface 32r that face opposite each other in the y direction. The element front surface 32s faces the same side as the first substrate front surface 31s, and the element back surface 32r faces the same side as the first substrate back surface 31r. Therefore, the element back surface 32r is bonded to the surface-side wiring 33s via a conductive bonding material. For example, Ag paste is used as the conductive bonding material.

[0050] The semiconductor light-emitting element 32 includes an anode electrode 36 and a cathode electrode 37. The anode electrode 36 is formed on the element front surface 32s. The cathode electrode 37 is formed on the element back surface 32r. As a result, the cathode electrode 37 is electrically connected to the front surface wiring 33s via a conductive bonding material. The front surface wiring 33s is electrically connected to the back surface wiring 33r via the through hole 34, and the back surface wiring 33r is electrically connected to the first mounting surface 24A via a conductive bonding material, so that the cathode electrode 37 is electrically connected to the heat sink 22.

[0051] The semiconductor light emitting element 32 has a light emitting surface 32a that emits light in the z direction. The light emitting surface 32a faces the same side as the tip surface 22a of the heat sink 22. When viewed from the z direction, the light emitting surface 32a is positioned so as to overlap with the opening 53 of the cap 50 (see FIG. 1 ).

[0052] As shown in Fig. 6, the second substrate 41 is attached to the second mounting surface 24B of the heat sink 22. More specifically, the second substrate 41 is joined to the second mounting surface 24B with a conductive bonding material such as solder paste or Ag paste. In this embodiment, the second substrate 41 is joined to the second mounting surface 24B with solder paste. Note that an insulating bonding material such as epoxy resin may be used as the bonding material for bonding the second substrate 41 to the heat sink 22. This bonding material may contain a filler such as aluminum nitride, silica, or alumina.

[0053] When viewed from the y direction, the second substrate 41 is formed in a rectangular shape with its longitudinal direction in the x direction and its lateral direction in the z direction. The size of the second substrate 41 in the x direction is larger than the size of the first substrate 31 in the x direction, and the size of the second substrate 41 in the z direction is larger than the size of the first substrate 31 in the z direction. The second substrate 41 is disposed at a distance from the base surface 21s of the base 21 in the z direction.

[0054] 3, the second substrate 41 is disposed on the second mounting surface 24B closer to the first mounting surface 24A. More specifically, the center of the second substrate 41 in the z direction is located closer to the first mounting surface 24A than the center of the second mounting surface 24B in the z direction. The second substrate 41 is disposed at the center of the second mounting surface 24B in the x direction. When viewed from the y direction, it can be said that the distance between the second substrate 41 and the first mounting surface 24A in the z direction is shorter than the distance between the second substrate 41 and the base surface 21s of the base 21 in the z direction.

[0055] The length of the second substrate 41 in the x direction is shorter than the length of the second mounting surface 24B in the x direction. In one example, the length of the second substrate 41 in the x direction is greater than half the length of the second mounting surface 24B in the x direction. The thickness of the second substrate 41 is, for example, not less than 0.1 mm and not more than 0.4 mm.

[0056] The second substrate 41 has an insulating second base material 41A. The second base material 41A supports the drive circuit elements 42. The second base material 41A is formed in a flat plate shape. For example, a glass epoxy substrate is used as the second base material 41A.

[0057] As shown in Figure 8, the second substrate 41 includes a second substrate front surface 41s and a second substrate back surface 41r that face opposite each other in the y direction. The second substrate front surface 41s faces the same side as the second mounting surface 24B, and the second substrate back surface 41r faces the second mounting surface 24B. The drive circuit elements 42 are mounted on the second substrate front surface 41s. Here, the second substrate front surface 41s is formed by the substrate front surface of the second base material 41A. The second substrate back surface 41r is formed by the substrate back surface of the second base material 41A.

[0058] As shown in FIG. 7 , in this embodiment, the second substrate 41 is attached to the second mounting surface 24B so that the second substrate surface 41s is at the same position as the first mounting surface 24A in the y direction. In other words, the distance DB between the second mounting surface 24B and the second substrate surface 41s of the second substrate 41 in the y direction is equal to the distance DH between the second mounting surface 24B and the first mounting surface 24A in the y direction. Here, if the difference between the distance DB and the distance DH is, for example, within 10% of the distance DH, then the distance DB and the distance DH can be said to be equal to each other. In other words, the second substrate surface 41s can be said to be at the same position as the first mounting surface 24A in the y direction.

[0059] 9, the second substrate 41 has surface-side wiring 45s formed on the second substrate surface 41s and a surface-side resist layer 46s covering the surface-side wiring 45s. As indicated by the dashed line in FIG. 9, the surface-side wiring 45s is formed in a rectangular shape that is slightly smaller than the second substrate surface 41s.

[0060] The front-side resist layer 46s is made of an insulating material and is formed over the entire second substrate surface 41s. The front-side resist layer 46s has a switching element opening 46a, a plurality of (two in this embodiment) capacitor openings 46b, and a wire opening 46c. The switching element opening 46a, each capacitor opening 46b, and wire opening 46c expose the front-side wiring 45s from the front-side resist layer 46s.

[0061] The switching element opening 46a is formed at the center of the second substrate surface 41s in the x direction. Multiple capacitor openings 46b are formed distributed on both sides of the switching element opening 46a in the x direction. Each capacitor opening 46b is formed closer to the first substrate 31 than the center of the second substrate surface 41s in the z direction. Each capacitor opening 46b is arranged at a position overlapping the switching element opening 46a when viewed from the x direction. As shown in FIG. 6 , the wire opening 46c is formed closer to the lead pin 23C in the x direction than the switching element opening 46a. When viewed from the y direction, the wire opening 46c has a rectangular shape with the x direction as the longitudinal direction and the z direction as the lateral direction.

[0062] 8 to 10 , the second substrate 41 includes a plurality of (16 in this embodiment) through holes 47. When viewed from the y direction, the plurality of through holes 47 are arranged within the switching element openings 46a. Each through hole 47 is formed from a conductive material. In one example, each through hole 47 is formed from a material containing Cu.

[0063] The plurality of through holes 47 are arranged in a lattice pattern. Each through hole 47 penetrates the second substrate 41 in its thickness direction (y direction). Each through hole 47 is connected to a surface-side wiring 45s.

[0064] A heat dissipation material 48 is provided inside each through hole 47. More specifically, the heat dissipation material 48 is provided so as to fill the inside of each through hole 47. The heat dissipation material 48 is formed, for example, from a metal material. In one example, the heat dissipation material 48 is formed from a material containing Cu. That is, the heat dissipation material 48 may be formed from the same material as the through holes 47. However, the heat dissipation material 48 may be formed from a material different from that of the through holes 47. The heat dissipation material 48 may be formed from a material having a higher thermal conductivity than the second substrate 41. In one example, the heat dissipation material 48 may be formed from an insulating material such as ceramic.

[0065] 10 , the second substrate 41 has a back-side resist layer 46r that covers the second substrate back surface 41r. The back-side resist layer 46r covers each through-hole 47 and the heat dissipation material 48. In this embodiment, the back-side resist layer 46r is formed over the entire second substrate back surface 41r. The back-side resist layer 46r is made of an insulating material. Therefore, the second substrate 41 is electrically insulated from the heat sink 22.

[0066] As shown in FIG. 6 , the second substrate surface 41 s is provided with a switching element 43 and a plurality of capacitors 44 mounted as the drive circuit elements 42. The switching element 43 is disposed within the switching element opening 46 a. Therefore, the switching element 43 is mounted on the surface-side wiring 45 s (see FIG. 9 ). More specifically, the switching element 43 is bonded to the surface-side wiring 45 s with a conductive bonding material such as solder paste or Ag paste. The switching element 43 can also be said to be disposed at the center of the second substrate surface 41 s in the x direction. The semiconductor light-emitting element 32 and the switching element 43 are arranged spaced apart from each other in the z direction.

[0067] The switching element 43 is a semiconductor element that controls the current supplied to the semiconductor light emitting element 32. The switching element 43 is, for example, a transistor. In this embodiment, a metal-oxide-semiconductor field-effect transistor (MOSFET) is used as the switching element 43. The switching element 43 includes a source electrode 43S, a drain electrode 43D (see FIG. 8 ), and a gate electrode 43G.

[0068] The switching element 43 is formed in a flat plate shape. As shown in FIG. 7 , the thickness TS of the switching element 43 is greater than the thickness TL of the semiconductor light emitting element 32. The shape of the switching element 43 when viewed from the y direction is rectangular. In this embodiment, the shape of the switching element 43 when viewed from the y direction is square. The shape of the switching element 43 when viewed from the y direction can be changed as desired. In one example, the shape of the switching element 43 when viewed from the y direction may be rectangular, with the z direction as the longitudinal direction and the x direction as the lateral direction.

[0069] 6 , the size of the switching element 43 in the x direction is larger than the size of the semiconductor light emitting element 32 in the x direction. In the example shown, the size of the switching element 43 in the x direction is smaller than twice the size of the semiconductor light emitting element 32 in the x direction. The size of the switching element 43 in the y direction is larger than the size of the semiconductor light emitting element 32 in the y direction. In the example shown, the size of the switching element 43 in the y direction is larger than twice but smaller than four times the size of the semiconductor light emitting element 32 in the y direction.

[0070] As shown in FIG. 8 , the switching element 43 has a switching element front surface 43s and a switching element back surface 43r that face opposite each other in the y direction. The switching element front surface 43s faces the same side as the second substrate front surface 41s. A source electrode 43S and a gate electrode 43G are formed on the switching element front surface 43s. The source electrode 43S is formed over most of the switching element front surface 43s. As shown in FIG. 6 , the gate electrode 43G is formed at one of both ends of the switching element front surface 43s in the z direction, the end opposite the first substrate 31, and in the center in the x direction.

[0071] 8, the switching element back surface 43r faces the same side as the second substrate back surface 41r. The switching element back surface 43r can also be said to face the second substrate front surface 41s. A drain electrode 43D is formed on the switching element back surface 43r. Thus, a vertical-structure MOSFET is used for the switching element 43 of this embodiment.

[0072] The switching element rear surface 43r is joined to the surface-side wiring 45s by a conductive bonding material, so that the drain electrode 43D is electrically connected to the surface-side wiring 45s via the conductive bonding material.

[0073] As shown in FIG. 6 , the source electrode 43S and the anode electrode 36 of the semiconductor light emitting element 32 are connected by multiple wires W1. This electrically connects the source electrode 43S and the anode electrode 36. Furthermore, the source electrode 43S and the connection portion 28A of the lead pin 23A are connected by a single wire W2. This electrically connects the source electrode 43S and the lead pin 23A. The gate electrode 43G and the connection portion 28B of the lead pin 23B are connected by a single wire W3. Furthermore, the surface-side wiring 45s exposed from the wire opening 46c and the connection portion 28C of the lead pin 23C are connected by a single wire W4. This electrically connects the surface-side wiring 45s and the lead pin 23C.

[0074] The wires W1 to W4 are bonding wires formed by a wire bonding device and are made of a conductor such as gold (Au), Al, or Cu. In this embodiment, the wires W1 to W4 are made of the same material (e.g., Cu). Note that at least one of the wires W1 to W4 may be made of a material different from the other wires.

[0075] The number of wires W1 can be changed as desired. In one example, the number of wires W1 is set according to the number of light-emitting portions 32A of the semiconductor light-emitting element 32. The numbers of wires W2, W3, and W4 can be changed as desired.

[0076] The plurality of capacitors 44 are electronic components that cooperate with the switching element 43 to supply current to the semiconductor light emitting element 32. As shown in FIG. 2 , each capacitor 44 is formed in a substantially rectangular parallelepiped shape. As shown in FIG. 6 , the shape of the capacitor 44 when viewed from the y direction is a rectangle with the z direction as the longitudinal direction and the x direction as the lateral direction. The plurality of capacitors 44 are arranged spaced apart from one another in the x direction. Therefore, the plurality of capacitors 44 are arranged such that the arrangement direction is the lateral direction of the capacitors 44.

[0077] Each capacitor 44 has a first electrode 44A and a second electrode 44B. The first electrode 44A and the second electrode 44B are formed to be spaced apart from each other in the z direction. In the illustrated example, the first electrode 44A is provided at one of both ends of the capacitor 44 in the z direction, the end closer to the leading end surface 22a of the heat sink 22. The second electrode 44B is provided at one of both ends of the capacitor 44 in the z direction, the end opposite the leading end surface 22a. In this embodiment, the multiple capacitors 44 have the same shape and size. Furthermore, the multiple capacitors 44 have the same capacitance.

[0078] Each capacitor 44 is disposed so as to straddle the z-direction between the first mounting surface 24A and the second substrate 41. That is, in each capacitor 44, the first electrode 44A is disposed closer to the first mounting surface 24A than the second substrate 41.

[0079] The first electrode 44A of each capacitor 44 is joined to the first mounting surface 24A with a conductive bonding material such as solder paste or Ag paste. This electrically connects the first electrode 44A of each capacitor 44 to the heat sink 22. Because the cathode electrode 37 (see FIG. 8 ) of the semiconductor light emitting element 32 is electrically connected to the heat sink 22, it can be said that the first electrode 44A is electrically connected to the cathode electrode 37 via the heat sink 22.

[0080] The first mounting surface 24A of the heat sink 22 includes a first region where the light-emitting unit 30 is mounted and a second region where the first electrode 44A of the capacitor 44 is mounted. In this embodiment, the first mounting surface 24A is configured as a flat surface where the first region and the second region are flush with each other.

[0081] The second electrode 44B of each capacitor 44 is bonded to the second substrate surface 41s of the second substrate 41 by a conductive adhesive. More specifically, the second electrode 44B of each capacitor 44 is positioned so as to overlap the capacitor opening 46b of the second substrate 41 when viewed from the y direction. Therefore, the second electrode 44B of each capacitor 44 is bonded to the surface-side wiring 45s exposed from the capacitor opening 46b by a conductive adhesive. As a result, the second electrode 44B of each capacitor 44 is electrically connected to the surface-side wiring 45s via the conductive adhesive. Because the drain electrode 43D (see FIG. 8 ) of the switching element 43 is electrically connected to the surface-side wiring 45s, the second electrode 44B of each capacitor 44 is electrically connected to the drain electrode 43D.

[0082] Each capacitor 44 is disposed at a position overlapping both the first substrate 31 (semiconductor light-emitting element 32) and the switching element 43 when viewed from the x direction. More specifically, the first electrode 44A of each capacitor 44 is disposed at a position overlapping the first substrate 31 (semiconductor light-emitting element 32) when viewed from the x direction. The second electrode 44B of each capacitor 44 is disposed at a position overlapping the switching element 43 when viewed from the x direction.

[0083] The first electrode 44A of each capacitor 44 is disposed so as to be shifted toward the switching element 43 with respect to the semiconductor light emitting element 32. In the example shown, the first electrode 44A of each capacitor 44 is disposed so as to be shifted toward the switching element 43 with respect to the center in the z direction of the semiconductor light emitting element 32 (the center in the z direction of the first substrate 31).

[0084] Furthermore, the capacitors 44 distributed on both sides of the switching element 43 in the x direction are arranged symmetrically with respect to the semiconductor light emitting element 32 and the switching element 43 when viewed in the y direction. As a result, a first wiring path in a loop through which a current flows from two capacitors 44 arranged on one side of the switching element 43 in the x direction to the semiconductor light emitting element 32 via the switching element 43, and a second wiring path in a loop through which a current flows from two capacitors 44 arranged on the other side of the switching element 43 in the x direction to the semiconductor light emitting element 32 via the switching element 43 are formed symmetrically with respect to the semiconductor light emitting element 32 and the switching element 43.

[0085] [Circuit Configuration of Semiconductor Light-Emitting Device] The circuit configuration of the semiconductor light-emitting device 10 having the configuration described above will be described with reference to Fig. 11. Fig. 11 shows the circuit configuration of a laser system LS that uses the semiconductor light-emitting device 10. As shown in Fig. 11, the laser system LS includes the semiconductor light-emitting device 10, a drive power supply DV, a resistor R, a diode D, and a driver circuit PM.

[0086] The driving power supply DV is a DC power supply having a positive and negative poles and supplies power to the semiconductor light-emitting device 10. A resistive element R is provided between the positive pole of the driving power supply DV and the semiconductor light-emitting device 10. A diode D is connected in anti-parallel to the semiconductor light-emitting element 32 to prevent backflow of current to the semiconductor light-emitting element 32. The diode D may be, for example, a Schottky barrier diode. The driver circuit PM outputs a control signal for controlling the on / off of the switching element 43 to the gate electrode 43G of the switching element 43. The driver circuit PM includes, for example, a square-wave oscillator circuit that generates a pulsed signal and a gate driver IC (Integrated Circuit) provided between the square-wave oscillator circuit and the semiconductor light-emitting device 10. The gate driver IC generates a control signal for the switching element 43 based on the signal from the square-wave oscillator circuit.

[0087] The semiconductor light emitting element 32 and the switching element 43 are connected in series. More specifically, the anode electrode 36 of the semiconductor light emitting element 32 and the source electrode 43S of the switching element 43 are electrically connected. The drain electrode 43D of the switching element 43 is electrically connected to the surface side wiring 45s (see FIG. 10 ). The cathode electrode 37 of the semiconductor light emitting element 32 is electrically connected to the heat sink 22.

[0088] The capacitor 44 is connected in parallel with the series circuit of the semiconductor light-emitting element 32 and the switching element 43. More specifically, a first electrode 44A of the capacitor 44 is electrically connected to the cathode electrode 37 of the semiconductor light-emitting element 32, and a second electrode 44B of the capacitor 44 is electrically connected to the drain electrode 43D of the switching element 43.

[0089] The drain electrode 43D of the switching element 43 is electrically connected to the surface-side wiring 45s. The anode electrode of the diode D is electrically connected to the heat sink 22 (see FIG. 6 ) via, for example, a lead pin 23D, and the cathode electrode of the diode D is electrically connected to the source electrode 43S via the lead pin 23A and the wire W2. This electrically connects the heat sink 22 to the cathode electrode 37 of the semiconductor light-emitting element 32. The source electrode 43S of the switching element 43 is electrically connected to the anode electrode 36 of the semiconductor light-emitting element 32 by the wire W1. Therefore, the diode D is connected in anti-parallel to the semiconductor light-emitting element 32.

[0090] The gate electrode 43G of the switching element 43 is electrically connected to the lead pin 23B. The driver circuit PM is electrically connected to the lead pin 23B. Therefore, the driver circuit PM is electrically connected to the gate electrode 43G of the switching element 43. The driver circuit PM and the negative electrode of the drive power supply DV are both connected to ground.

[0091] The laser system LS configured as described above operates as follows: When the switching element 43 is turned off by a control signal from the driver circuit PM, the capacitor 44 is charged by the drive power supply DV. When the switching element 43 is turned on by a control signal from the driver circuit PM, the capacitor 44 is discharged, causing a current to flow through the semiconductor light-emitting element 32. This causes the semiconductor light-emitting element 32 to emit pulsed laser light.

[0092] [Semiconductor Light-Emitting Unit] The configuration of a semiconductor light-emitting unit 100 as an application example of the semiconductor light-emitting device 10 will be described with reference to FIGS.

[0093] Fig. 12 shows a perspective structure of the semiconductor light emitting unit 100 as viewed from the opposite side to the light emission direction of the semiconductor light emitting element 32. Fig. 13 shows a side structure of the semiconductor light emitting unit 100 of Fig. 12. Fig. 14 shows an enlarged side structure of the semiconductor light emitting device 10 of Fig. 13 and its surroundings. The semiconductor light emitting device 10 of the semiconductor light emitting unit 100 can be the semiconductor light emitting device 10 of any of the first to sixth embodiments.

[0094] 12 , the semiconductor light emitting unit 100 includes a semiconductor light emitting device 10 and a heat sink 110 that dissipates heat from the semiconductor light emitting device 10. The semiconductor light emitting unit 100 further includes a circuit board 120 electrically connected to the semiconductor light emitting device 10.

[0095] The heat sink 110 includes a heat sink base 130 and a cap cover 140 that stands upright from the heat sink base 130. The heat sink 110 is formed of a material that includes any one of stainless steel, Fe, Al, and Cu, for example.

[0096] The heat dissipation base 130 and the cap cover 140 are formed separately and then joined together by welding or the like. Therefore, the heat dissipation base 130 and the cap cover 140 may be made of different materials. Alternatively, the heat dissipation base 130 and the cap cover 140 may be formed as a single member.

[0097] The heat dissipation base 130 is formed in a plate shape with its thickness direction in the y direction. The heat dissipation base 130 has a volume that is sufficiently large compared to the semiconductor light emitting device 10. When viewed from the y direction, the heat dissipation base 130 has a rectangular shape with its short side direction in the z direction and its long side direction in the x direction. The heat dissipation base 130 has a base surface 131, a base back surface 132 opposite the base surface 131, and four base side surfaces 133 to 136 that connect the base surface 131 and the base back surface 132.

[0098] Base side surface 133 and base side surface 134 are spaced apart from each other in the x direction. Each of base side surface 133 and base side surface 134 is a flat surface extending along the yz plane. Base side surface 135 and base side surface 136 are spaced apart from each other in the z direction. Each of base side surface 135 and base side surface 136 is a flat surface extending along the xy plane.

[0099] The cap cover part 140 extends in the y direction from the base surface 131 of the heat dissipation base 130. In other words, the base surface 131 is the surface on which the cap cover part 140 is erected. The cap cover part 140 is formed in a flat plate shape with its thickness direction in the z direction. The size of the cap cover part 140 in the x direction is smaller than the size of the heat dissipation base 130 in the x direction. The cap cover part 140 has a first cover surface 141 and a second cover surface 142 that face opposite each other in the z direction. The first cover surface 141 faces the same side as the base side surface 135, and the second cover surface 142 faces the same side as the base side surface 136. As shown in FIG. 13 , in this embodiment, the first cover surface 141 is flush with the base side surface 135.

[0100] 14 , the cap cover part 140 has a through-hole 143 that penetrates in its thickness direction (z direction). When viewed from the z direction, the through-hole 143 is circular. The inner diameter of the through-hole 143 is equal to the outer diameter of the cap 50 of the semiconductor light-emitting device 10.

[0101] As shown in FIGS. 12 and 13 , the circuit board 120 is disposed on the base surface 131 of the heat dissipation base 130. The circuit board 120 is disposed on the base surface 131 of the heat dissipation base 130, spaced apart from the base back surface 132 in the thickness direction (y direction) of the heat dissipation base 130. In the illustrated example, a gap is formed between the circuit board 120 and the base surface 131 in the y direction. The circuit board 120 is formed in a flat plate shape with the thickness direction being the y direction. The circuit board 120 is disposed closer to the base side surface 135 than to the base side surface 136 in the z direction. In this embodiment, the circuit board 120 is disposed adjacent to the cap cover 140. The circuit board 120 is disposed parallel to the base surface 131 of the heat dissipation base 130. As shown in FIG. 12 , the size of the circuit board 120 in the x direction is greater than the size of the cap cover 140 in the x direction.

[0102] For example, at least one of the diode D, the resistor R, and the driver circuit PM of the laser system LS shown in Fig. 11 may be mounted on the circuit board 120. In this embodiment, the diode D, the resistor R, and the driver circuit PM are each mounted on the circuit board 120.

[0103] Next, a mounting structure of the semiconductor light emitting device 10 to the heat sink 110 and the circuit board 120 will be described. As shown in Fig. 14, the semiconductor light emitting device 10 is mounted to the cap cover part 140. More specifically, the cap cover part 140 is connected to the side surface (the outer peripheral surface of the cylindrical part 51) of the cap 50 of the semiconductor light emitting device 10 so as to be heat-transferably connected to the side surface of the cap 50. In this embodiment, the cap 50 is press-fitted into the through hole 143 of the cap cover part 140 from the second cover surface 142 side, so as to be heat-transferably connected to the side surface of the cap 50.

[0104] Note that the cap 50 may be loosely fitted into the through-hole 143 so that the cap cover part 140 is connected to the side surface of the cap 50 in a heat-transferable manner. In other words, the cap 50 may be inserted into the through-hole 143 within a range where heat from the side surface of the cap 50 is transferred to the cap cover part 140.

[0105] The side of the cap 50 is heat-transferably connected to the cap cover portion 140 with the opening 53 facing in a direction intersecting the thickness direction (y direction) of the heat dissipation base 130. In one example, the side of the cap 50 is heat-transferably connected to the cap cover portion 140 with the opening 53 facing in a direction perpendicular to the thickness direction (y direction) of the heat dissipation base 130. More specifically, when the cap 50 is press-fitted into the through-hole 143, the top plate portion 52 of the cap 50 faces the z direction. That is, the opening 53 formed in the top plate portion 52 opens toward the z direction. In this way, the semiconductor light-emitting unit 100 is configured so that the opening 53 of the cap 50 (see FIG. 1 ) faces laterally (z direction). Therefore, the semiconductor light-emitting element 32 emits light in the z direction.

[0106] In this embodiment, the inner surface that constitutes the through hole 143 is connected to the entire periphery of the side surface of the cap 50 in a heat-transferable manner. More specifically, the inner surface that constitutes the through hole 143 covers the entire periphery of the side surface of the cap 50. In other words, the entire periphery of the side surface of the cap 50 is press-fitted into the inner surface that constitutes the through hole 143. Therefore, the side surface of the cap 50 is in contact with the inner surface that constitutes the through hole 143 over the entire periphery.

[0107] The semiconductor light emitting device 10 is attached to the cap cover part 140 so that its thickness direction intersects with the thickness direction of the heat dissipation base 130. In one example, the semiconductor light emitting device 10 is attached to the cap cover part 140 so that its thickness direction is perpendicular to the thickness direction of the heat dissipation base 130.

[0108] With the cap 50 press-fitted into the through-hole 143, the base 21 is in contact with the cap cover portion 140. In this embodiment, the entire portion of the base surface 21s of the base 21 that is exposed from the cap 50 is in contact with the second cover surface 142 of the cap cover portion 140. In this manner, in this embodiment, by attaching the semiconductor light emitting device 10 to the cap cover portion 140, the side surface of the cap 50 is connected to the cap cover portion 140 in a manner that allows heat to be transferred, and the base 21 is also connected to the cap cover portion 140 in a manner that allows heat to be transferred.

[0109] The thickness TCC of the cap cover portion 140 is thicker than the height dimension HCP of the cap 50. Therefore, the top plate portion 52 of the cap 50 is disposed closer to the second cover surface 142 than the first cover surface 141 of the cap cover portion 140. Here, the thickness TCC of the cap cover portion 140 can be defined by the distance between the first cover surface 141 and the second cover surface 142 in the z direction. The height dimension HCP of the cap 50 can be defined by the distance between the base surface 21s of the base 21 and the top plate portion 52 of the cap 50 in the z direction.

[0110] An opening cover member 150 may be attached to the cap cover part 140. The opening cover member 150 is joined to the first cover surface 141 of the cap cover part 140 with an adhesive or the like. The opening cover member 150 covers the through hole 143.

[0111] The opening cover member 150 is formed in a cylindrical shape with a bottom. A bottom 151 of the opening cover member 150 is provided at a position away from the first cover surface 141. An opening 152 is formed in this bottom 151. The opening 152 is formed at a position overlapping with the through-hole 143 when viewed from the z direction.

[0112] One or more lenses can be housed inside the opening cover member 150. As a result, light from the semiconductor light emitting device 10 passes through the through-hole 143 and the lens inside the opening cover member 150, and is emitted from the opening 152 in the z direction.

[0113] 14 , with the cap 50 press-fitted into the through-hole 143, the plurality of lead pins 23A-23D of the semiconductor light-emitting device 10 are mounted on the circuit board 120. The lead pins 23A-23D are mounted on the end of the circuit board 120 adjacent to the cap cover portion 140 in the z direction. Each of the lead pins 23A-23D is inserted into the circuit board 120 in the y direction by being bent. The portion of each of the lead pins 23A-23D inserted into the circuit board 120 is joined to the circuit board 120 by a conductive bonding material such as solder paste. In this manner, each of the terminal portions 29A-29D of the lead pins 23A-23D includes a first portion extending from the base 21 in the z direction, a second portion extending in the y direction and mounted on the circuit board 120, and a bent portion formed between the first and second portions.

[0114] The relationship between the thickness TCC of the cap cover portion 140 and the height dimension HCP of the cap 50 can be changed as desired. In one example, the thickness TCC of the cap cover portion 140 and the height dimension HCP of the cap 50 may be equal to each other. Furthermore, the thickness TCC of the cap cover portion 140 may be thinner than the height dimension HCP of the cap 50. When the thickness TCC of the cap cover portion 140 is thinner than the height dimension HCP of the cap 50, the top plate portion 52 of the cap 50 protrudes from the first cover surface 141 of the cap cover portion 140.

[0115] When viewed from the z direction, the circuit board 120 is disposed at a position overlapping the base 21. The circuit board 120 is disposed at a position closer to the heat dissipation base 130 than the center of the base 21 in the y direction.

[0116] [Operation] The operation of both the semiconductor light emitting device 10 and the semiconductor light emitting unit 100 of this embodiment will be described.

[0117] (Function of Semiconductor Light-Emitting Unit) First, the function of the semiconductor light-emitting unit 100 will be described with reference to Figures 15 to 21. Figure 15 shows a perspective view of a semiconductor light-emitting unit 100X as a comparative example.

[0118] 15, the semiconductor light emitting unit 100X of the comparative example is mounted on the circuit board 120 so that the thickness direction of the circuit board 120 is the same as the light emission direction. Therefore, in the semiconductor light emitting unit 100X of the comparative example, the lead pins 23A to 23D are mounted in through holes (not shown) formed in the circuit board 120 without being bent. The semiconductor light emitting unit 100X of the comparative example includes the semiconductor light emitting device 10X of the comparative example shown in FIG.

[0119] 16 shows an example of the internal structure of a semiconductor light emitting device 10X of the comparative example. The semiconductor light emitting device 10X of the comparative example differs from the semiconductor light emitting device 10 of the present embodiment mainly in that the first substrate 31 is omitted and the semiconductor light emitting element 32 is mounted on the second substrate 41, and in that the step portion 25 is omitted from the heat sink 22. For ease of explanation, components of the semiconductor light emitting device 10X of the comparative example that are common to the semiconductor light emitting device 10 of the present embodiment are denoted by the same reference numerals, and their explanations will be omitted.

[0120] The heat sink 22X of the semiconductor light emitting device 10X of the comparative example differs from the heat sink 22 of the semiconductor light emitting device 10 of the present embodiment (see FIG. 2 ) primarily in that it does not have a stepped portion 25 (protrusion 26). The heat sink 22X has a mounting surface 24X. Because the heat sink 22X does not have a stepped portion 25, the mounting surface 24X is flat along the xz plane. A second substrate 41 is bonded to the mounting surface 24X with a conductive adhesive. A semiconductor light emitting element 32, a switching element 43, and four capacitors 44 are mounted on a second substrate surface 41s of the second substrate 41. The semiconductor light emitting element 32 is positioned closer to the tip surface 22a of the heat sink 22 than the switching element 43. When viewed from the z direction, the semiconductor light emitting element 32 is positioned so as to overlap the switching element 43. As with the semiconductor light emitting device 10 of the first embodiment, the four capacitors 44 are distributed two by two in the x direction relative to the switching element 43.

[0121] Although not shown, the second substrate 41 includes first surface-side wiring and second surface-side wiring. The first surface-side wiring and the second surface-side wiring are spaced apart from each other in the z-direction. The first surface-side wiring is located closer to the tip surface 22a of the heat sink 22 than the second surface-side wiring. The semiconductor light-emitting element 32 and the first electrode 44A of each capacitor 44 are mounted on the first surface-side wiring. Therefore, the cathode electrode 37 (see FIG. 8) of the semiconductor light-emitting element 32 and the first electrode 44A of each capacitor 44 are electrically connected via the first surface-side wiring. The switching element 43 and the second electrode 44B of each capacitor 44 are mounted on the second surface-side wiring. Therefore, the drain electrode 43D (see FIG. 8) of the switching element 43 and the second electrode 44B of each capacitor 44 are electrically connected via the second surface-side wiring.

[0122] Figure 17 shows the relationship between the heat transfer coefficient and the temperature of the semiconductor light-emitting element 32 of the comparative example semiconductor light-emitting unit 100X when the frequency of the control signal that drives the switching element 43, i.e., the switching frequency of the switching element 43, is changed to 10 kHz, 50 kHz, 100 kHz, and 200 kHz.

[0123] FIG. 18 shows the relationship between the heat transfer coefficient and the temperature of the semiconductor light emitting element 32 of the semiconductor light emitting unit 100 of this embodiment when the switching frequency of the switching element 43 is changed to 10 kHz, 50 kHz, 100 kHz, and 200 kHz.

[0124] 17 and 18, the graph for the switching frequency of the switching element 43 is shown by a two-dot chain line at 10 kHz, a graph for 50 kHz at 50 kHz at 50 kHz at 100 kHz at 100 kHz at 100 kHz at 200 kHz at 200 kHz at 200 kHz at 200 kHz at 200 kHz at 200 kHz at 200 kHz at 200 kHz at 200 kHz at 200 kHz at 1 ...100 kHz at 100 kHz at 100 kHz at 200 kHz at 200 kHz at

[0125] 17 and 18 show the results of heat conduction analysis for natural air cooling, forced air cooling, and water cooling. The range of the heat transfer coefficient for natural air cooling is, for example, 5 W / m ２ / K or more 50W / m ２ / K or less, and the range of the heat transfer coefficient in forced air cooling is, for example, 100 W / m２ / K or more 500W / m ２ / K, and the heat transfer coefficient of water cooling is, for example, 1000 W / m ２ In these heat conduction analyses, the pulse width of the control signal that turns on the switching element 43 is set to 2 nS, and the peak optical output of the semiconductor light-emitting device 10 (in this embodiment, the total optical output of the four light-emitting portions 32A of the semiconductor light-emitting element 32) is set to 500 W.

[0126] 17 and 18 , in both the semiconductor light-emitting unit 100X of the comparative example and the semiconductor light-emitting unit 100 of this embodiment, the temperature of the semiconductor light-emitting element 32 increases at the same heat transfer coefficient as the switching frequency of the switching element 43 increases in the order of 10 kHz, 50 kHz, 100 kHz, and 200 kHz. Also, in both the semiconductor light-emitting unit 100X of the comparative example and the semiconductor light-emitting unit 100 of this embodiment, the temperature of the semiconductor light-emitting element 32 increases as the heat transfer coefficient decreases. The amount of temperature increase of the semiconductor light-emitting element 32 relative to the amount of decrease in the heat transfer coefficient increases as the switching frequency of the switching element 43 increases in the order of 10 kHz, 50 kHz, 100 kHz, and 200 kHz.

[0127] 17 , in the semiconductor light-emitting unit 100X of the comparative example, when the switching frequency of the switching element 43 is set to 50 kHz, 100 kHz, and 200 kHz during natural cooling, the temperature of the semiconductor light-emitting element 32 exceeds 100°C. Therefore, depending on the heat-resistant temperature of the semiconductor light-emitting element 32, the semiconductor light-emitting unit 100X of the comparative example may not be able to tolerate a switching frequency of the switching element 43 of 50 kHz or higher during natural cooling. This is thought to be because the semiconductor light-emitting device 10X of the comparative example has difficulty dissipating heat, since the main heat dissipation path in the semiconductor light-emitting device 10X of the comparative example is the path through which heat is transferred from the lead pins 23A-23D to the circuit board 120.

[0128] On the other hand, as shown in FIG. 18 , in the semiconductor light-emitting unit 100 of this embodiment, even when the switching frequency of the switching element 43 is set to 200 kHz under natural cooling, the temperature of the semiconductor light-emitting element 32 is less than 60°C (approximately 50°C). Therefore, in the semiconductor light-emitting unit 100 of this embodiment, a switching frequency of 200 kHz is acceptable under natural cooling. Thus, the semiconductor light-emitting unit 100 of this embodiment has better heat dissipation performance than the semiconductor light-emitting unit 100X of the comparative example. This is thought to be because the cap cover portion 140 of the heat sink 110 is in contact with the cap 50 and base 21 of the semiconductor light-emitting device 10, and heat from the semiconductor light-emitting device 10 is transferred from the cap 50 and base 21 to the cap cover portion 140. In other words, the semiconductor light-emitting unit 100 of this embodiment has more heat dissipation paths than the semiconductor light-emitting unit 100X of the comparative example, which is thought to make it easier for the semiconductor light-emitting element 32 to dissipate heat. Furthermore, it is believed that the thermal conductivity of the first substrate 31 is higher than that of the second substrate 41, and therefore heat from the semiconductor light emitting element 32 is more easily transferred from the first substrate 31 to the heat sink 22. Therefore, the semiconductor light emitting unit 100 of this embodiment can increase the switching frequency of the switching element 43 compared to the semiconductor light emitting unit 100X of the comparative example.

[0129] FIG. 19 shows the relationship between the heat transfer coefficient and the temperature of the semiconductor light emitting element 32 of the semiconductor light emitting unit 100 of this embodiment when the material constituting the heat sink 110 is changed. In FIG. 19 , Cu, Al, Fe, and stainless steel are used as the materials constituting the heat sink 110. The thermal conductivity of Cu is 402 W / mK, the thermal conductivity of Al is 237 W / mK, the thermal conductivity of Fe is 80.3 W / mK, and the thermal conductivity of stainless steel is 15 W / mK. In FIG. 19 , the heat sink 110 has a heat sink base 130 with dimensions of 100 mm in the x direction, 100 mm in the z direction, and 10 mm in the y direction (thickness). In Figure 19, the graph with a dotted and dashed line represents the case where the material constituting the heat sink 110 is Cu, the graph with a single dotted and dashed line represents the case where the material constituting the heat sink 110 is Al, the graph with a dashed line represents the case where the material constituting the heat sink 110 is Fe, and the graph with a solid line represents the case where the material constituting the heat sink 110 is stainless steel.

[0130] The graph in Figure 19 shows the results of heat conduction analysis for natural air cooling, forced air cooling, and water cooling. The ranges of heat transfer coefficients for natural air cooling, forced air cooling, and water cooling are the same as those in the graphs in Figures 17 and 18. In these heat conduction analyses, the pulse width of the control signal that turns on the switching element 43 is set to 2 nS, and the peak optical output of the semiconductor light emitting element 32 is set to 500 W.

[0131] As shown in FIG. 19 , as the heat transfer coefficient decreases, the temperature variation of the semiconductor light-emitting element 32 increases depending on the type of material making up the heat sink 110. In other words, the temperature variation of the semiconductor light-emitting element 32 increases depending on the type of material making up the heat sink 110 in the following order: water cooling, forced air cooling, and natural air cooling. With natural air cooling, a maximum temperature difference of approximately 30°C occurs for the semiconductor light-emitting element 32 between Cu, which has the highest thermal conductivity, and stainless steel, which has the lowest. On the other hand, with water cooling, Cu, Al, Fe, and stainless steel are approximately 40°C, so there is almost no temperature difference between Cu, which has the highest thermal conductivity, and stainless steel, which has the lowest thermal conductivity. Furthermore, Cu, Al, and Fe do not exhibit significant temperature variation for the semiconductor light-emitting element 32. Since Fe is approximately 70°C with natural air cooling, any of Cu, Al, and Fe can be used as the material making up the heat sink 110 when natural air cooling is used. With forced air cooling and water cooling, stainless steel can also be used as the material making up the heat sink 110.

[0132] 20 shows the relationship between the volume of the heat sink 110 (heat sink base 130) and the temperature of the semiconductor light emitting element 32. In FIG. 20, Al is used as the material constituting the heat sink 110. Also, in FIG. 20, the heat transfer coefficient is set to 5 W / m ２ / K, 10W / m ２ / K, 100W / m ２ / K, and 1000 W / m ２ / K and the volume of the heat sink 110 is changed. ２ / K and 10 W / m ２ / K corresponds to natural air cooling, and the heat transfer coefficient is 100 W / m ２ / K corresponds to forced air cooling, and the heat transfer coefficient is 1000 W / m ２ / K corresponds to the case of water cooling. In the graph of FIG. 20, the dashed double-dashed line indicates the case where the heat transfer coefficient is 1000 W / m ２ / K, and the dashed line graph shows the case where the heat transfer coefficient is 100 W / m ２ / K, and the dashed line indicates a heat transfer coefficient of 10 W / m ２ / K, and the solid line in the graph indicates a heat transfer coefficient of 5 W / m ２ This is the case for / K.

[0133] As shown in FIG. 20, when the heat transfer coefficient is 100 W / m ２ / K and 1000 W / m ２ / K, that is, in the case of forced air cooling and water cooling, the temperature of the semiconductor light emitting element 32 hardly changes with the change in the volume of the heat sink 110 (heat dissipation base 130). ２ / K and 10 W / m ２ / K, that is, in the case of natural air cooling, the temperature of the semiconductor light emitting element 32 changes significantly with the change in the volume of the heat sink 110 (heat sink base 130). ３ When the volume of the heat sink 110 (heat sink base 130) is less than 30,000 mm, the temperature of the semiconductor light emitting element 32 increases rapidly as the volume decreases. ３ In the above range, the temperature of the semiconductor light emitting element 32 increases gradually as the volume decreases. ３ 19 and 20, if the thermal conductivity is, for example, 50 W / mK or more, the volume of the heat sink 110 (heat sink base 130) is preferably 30,000 mm ３ It is believed that even if the temperature is in the range of less than 100° C., the temperature of the semiconductor light emitting element 32 can be kept at 100° C. or less.

[0134] (Function of Semiconductor Light-Emitting Device) Next, the function of the semiconductor light-emitting device 10 will be described with reference to Fig. 18 and Fig. 21. Fig. 21 shows the results of a heat conduction analysis when the semiconductor light-emitting device 10X of the comparative example is applied to the semiconductor light-emitting unit 100. As described above, Fig. 18 shows the results of a heat conduction analysis when the semiconductor light-emitting device 10 of this embodiment is applied to the semiconductor light-emitting unit 100. Similar to Fig. 18, Fig. 21 shows the relationship between the heat transfer coefficient and the temperature of the semiconductor light-emitting element 32 when the switching frequency of the switching element 43 is changed to 10 kHz, 50 kHz, 100 kHz, and 200 kHz.

[0135] In Figure 21 , as in Figure 18 , the graph for a switching frequency of the switching element 43 of 10 kHz is shown by a two-dot chain line, the graph for 50 kHz is shown by a single-dot chain line, the graph for 100 kHz is shown by a dashed line, and the graph for 200 kHz is shown by a solid line. The graph in Figure 21 also shows the results of heat conduction analysis for natural air cooling, forced air cooling, and water cooling. The ranges of heat transfer coefficients for natural air cooling, forced air cooling, and water cooling are the same as those in Figure 18 . In these heat conduction analyses, the pulse width of the control signal that turns on the switching element 43 is set to 2 nS (2 nanoseconds), and the peak optical output of the semiconductor light emitting element 32 is set to 500 W.

[0136] 18 and 21 , when the switching frequency of the switching element 43 is 10 kHz, the temperature of the semiconductor light-emitting element 32 is almost the same between the semiconductor light-emitting device 10X of the comparative example and the semiconductor light-emitting device 10 of this embodiment. As the switching frequency of the switching element 43 increases to 50 kHz, 100 kHz, and 200 kHz, the degree to which the temperature of the semiconductor light-emitting element 32 in the semiconductor light-emitting device 10 of this embodiment is lower than that in the semiconductor light-emitting device 10X of the comparative example increases.

[0137] In particular, when the switching frequency of the switching element 43 is set to 200 kHz under natural cooling, the temperature of the semiconductor light-emitting element 32 in the semiconductor light-emitting device 10X of the comparative example is approximately 90°C, whereas the temperature of the semiconductor light-emitting element 32 in the semiconductor light-emitting device 10 of this embodiment is less than 60°C (approximately 50°C). Thus, when the switching frequency of the switching element 43 is set to 200 kHz under natural cooling, the temperature of the semiconductor light-emitting element 32 in the semiconductor light-emitting device 10 of this embodiment is nearly 40°C lower than that of the semiconductor light-emitting device 10X of the comparative example. Thus, the semiconductor light-emitting device 10 of this embodiment has better heat dissipation performance than the semiconductor light-emitting device 10X of the comparative example. This is thought to be because the thermal conductivity of the first substrate 31 is higher than that of the second substrate 41, so heat from the semiconductor light-emitting element 32 is more easily transferred from the first substrate 31 to the heat sink 22. Therefore, the semiconductor light-emitting device 10 of this embodiment can have a higher switching frequency of the switching element 43 than the semiconductor light-emitting device 10X of the comparative example.

[0138] [Effects] The semiconductor light emitting device 10 and the semiconductor light emitting unit 100 of this embodiment provide the following effects.

[0139] (1-1) The semiconductor light-emitting device 10 comprises a base 21, a conductive heat sink 22 erected on the base 21, a first substrate 31 and a second substrate 41 attached to the heat sink 22 so as to be spaced apart from each other, a semiconductor light-emitting element 32 mounted on the first substrate 31, and a drive circuit element 42 mounted on the second substrate 41 and for driving the semiconductor light-emitting element 32.

[0140] According to this configuration, the first substrate 31 on which the semiconductor light-emitting element 32 is mounted and the second substrate 41 on which the drive circuit element 42 is mounted are attached to the heat sink 22 so as to be spaced apart from each other, so that the heat from the semiconductor light-emitting element 32 is transferred to the heat sink 22 via the first substrate 31. In other words, the heat from the semiconductor light-emitting element 32 is less likely to be transferred to the second substrate 41. Therefore, the heat from the semiconductor light-emitting element 32 can be prevented from affecting the drive circuit element 42.

[0141] (1-2) The thermal conductivity of the first substrate 31 is higher than that of the second substrate 41. With this configuration, heat from the semiconductor light emitting element 32 is more easily transferred to the heat sink 22 via the first substrate 31. Therefore, the heat dissipation performance of the semiconductor light emitting device 10 can be improved.

[0142] (1-3) The difference between the linear expansion coefficient of the first substrate 31 and the linear expansion coefficient of the semiconductor light emitting element 32 is smaller than the difference between the linear expansion coefficient of the heat sink 22 and the linear expansion coefficient of the semiconductor light emitting element 32. This configuration can reduce the force applied to the semiconductor light emitting element 32 due to the difference in the linear expansion coefficient between the first substrate 31 and the semiconductor light emitting element 32. Therefore, it is possible to reduce the influence of temperature changes on the electrical characteristics of the semiconductor light emitting element 32.

[0143] (1-4) The first substrate 31 is made of any one of aluminum nitride, alumina, copper-tungsten alloy, copper-aluminum nitride-copper, copper-diamond alloy, and silver-diamond alloy.

[0144] With this configuration, it is possible to achieve both the effect that heat from the semiconductor light-emitting element 32 is more easily transferred to the heat sink 22 via the first substrate 31 and the effect that the force applied to the semiconductor light-emitting element 32 due to the difference in the linear expansion coefficients between the first substrate 31 and the semiconductor light-emitting element 32 is reduced.

[0145] (1-5) The heat sink 22 includes a second mounting surface 24B to which the second substrate 41 is attached, and a first mounting surface 24A to which the first substrate 31 is attached, and which is attached closer to the tip of the heat sink 22 than the second mounting surface 24B. The first mounting surface 24A protrudes from the second mounting surface 24B in a thickness direction (y direction) that is perpendicular to the erection direction (z direction) of the heat sink 22.

[0146] This configuration reduces the deviation in the y direction between the position of the first mounting surface 24A of the heat sink 22 and the position of the second substrate surface 41s of the second substrate 41. Therefore, for example, when a component arranged to straddle the z direction between the first mounting surface 24A and the second substrate 41 is attached to both the first mounting surface 24A and the second substrate surface 41s, it is no longer necessary to take into consideration the deviation in the y direction between the position of the first mounting surface 24A of the heat sink 22 and the position of the second substrate surface 41s of the second substrate 41, and the component can be easily arranged.

[0147] (1-6) The drive circuit element 42 includes a capacitor 44 having a first electrode 44A and a second electrode 44B. The first electrode 44A of the capacitor 44 is mounted on the first mounting surface 24A of the heat sink 22, and the second electrode 44B of the capacitor 44 is mounted on the second substrate 41.

[0148] According to this configuration, the first electrode 44A of the capacitor 44 is mounted on the first mounting surface 24A of the heat sink 22, and therefore the first electrode 44A is electrically connected to the semiconductor light-emitting element 32 via the first mounting surface 24A and the first substrate 31. Therefore, the conductive path between the first electrode 44A and the semiconductor light-emitting element 32 can be made shorter than when the first electrode 44A of the capacitor 44 is mounted on the second substrate 41.

[0149] (1-7) The second substrate 41 includes a second substrate surface 41s on which the drive circuit elements 42 are mounted. The first mounting surface 24A and the second substrate surface 41s are located at the same position in the y direction. This configuration allows the capacitor 44, which is positioned across the z-direction between the first mounting surface 24A and the second substrate surface 41s, to be mounted on the first mounting surface 24A and the second substrate surface 41s without being significantly tilted in the y direction relative to the z direction when viewed from the x direction. Therefore, it is not necessary to consider the misalignment between the y-direction position of the first mounting surface 24A of the heat sink 22 and the y-direction position of the second substrate surface 41s of the second substrate 41, and the capacitor 44 can be easily mounted on the first mounting surface 24A and the second substrate surface 41s.

[0150] (1-8) The first mounting surface 24A is configured as a flat surface such that the first region where the light-emitting unit 30 is mounted is flush with the second region where the capacitor 44 is mounted. With this configuration, the conductive path between the first electrode 44A of the capacitor 44 and the cathode electrode 37 of the semiconductor light-emitting element 32 can be made shorter than in a configuration in which a step is formed between the first region and the second region.

[0151] (1-9) The semiconductor light emitting element 32 has a plurality of light emitting portions 32 A. According to this configuration, since the semiconductor light emitting element 32 has a plurality of light emitting portions 32 A, the light intensity of the semiconductor light emitting element 32 can be increased.

[0152] On the other hand, increasing the light intensity of the semiconductor light-emitting element 32 increases the amount of heat generated by the semiconductor light-emitting element 32. In other words, the temperature of the semiconductor light-emitting element 32 is likely to rise. In this regard, the semiconductor light-emitting device 10 of this embodiment includes the first substrate 31 on which the semiconductor light-emitting element 32 is mounted, making it difficult for heat from the semiconductor light-emitting element 32 to be transferred to the second substrate 41. Therefore, it is possible to achieve both an increase in the light intensity of the semiconductor light-emitting element 32 and suppression of the heat from the semiconductor light-emitting element 32 from affecting the drive circuit element 42. In addition, by using a substrate with better heat dissipation properties for the first substrate 31 than the second substrate 41, heat from the semiconductor light-emitting element 32 is more likely to be transferred to the heat sink 22 via the first substrate 31. Therefore, it is possible to suppress an excessive rise in the temperature of the semiconductor light-emitting element 32.

[0153] (1-10) When viewed from the x direction, the first electrode 44A of the capacitor 44 is disposed at a position overlapping the first substrate 31 (semiconductor light-emitting element 32). With this configuration, the conductive path between the first electrode 44A and the first substrate 31 (semiconductor light-emitting element 32) can be shortened compared to a configuration in which the first electrode 44A of the capacitor 44 is disposed at a position shifted in the z direction relative to the first substrate 31 (semiconductor light-emitting element 32).

[0154] (1-11) The semiconductor light emitting element 32 includes an anode electrode 36 and a cathode electrode 37. The first substrate 31 includes a through hole 34 that electrically connects the cathode electrode 37 and the heat sink 22.

[0155] According to this configuration, the semiconductor light emitting element 32 and the heat sink 22 are electrically connected by the through hole 34, and the heat of the semiconductor light emitting element 32 can be efficiently transferred to the heat sink 22.

[0156] (1-12) The through-hole 34 is provided in a position on the first substrate 31 that overlaps the semiconductor light-emitting element 32. With this configuration, the conductive path between the semiconductor light-emitting element 32 and the heat sink 22 can be shortened.

[0157] (1-13) The first substrate 31 includes a heat dissipation material 35 provided in the through-hole 34. With this configuration, the heat from the semiconductor light emitting element 32 can be transferred to the heat sink 22 more efficiently.

[0158] (1-14) The semiconductor light emitting unit 100 includes a semiconductor light emitting device 10 and a heat sink 110 to which the semiconductor light emitting device 10 is attached. The semiconductor light emitting device 10 includes a semiconductor light emitting element 32, a drive circuit element 42, and a cap 50 having an opening 53 that opens in one direction and a side surface (the outer peripheral surface of a cylindrical portion 52) facing a direction intersecting the one direction, and covering the semiconductor light emitting element 32 and the drive circuit element 42. The heat sink 110 includes a plate-shaped heat dissipation base 130 and a cap cover portion 140 that stands upright from the heat dissipation base 130 and is connected to the side surface of the cap 50 in a heat-transferable manner with the opening 53 of the cap 50 facing a direction (z direction) intersecting the thickness direction (y direction) of the heat dissipation base 130.

[0159] With this configuration, heat from the semiconductor light emitting element 32 is transferred to the cap cover part 140 via the side surface of the cap 50 (the outer peripheral surface of the cylindrical part 52). This improves heat dissipation performance compared to a semiconductor light emitting unit that does not include the cap cover part 140 that is heat-transferably connected to the side surface of the cap 50. This prevents the temperature of the semiconductor light emitting element 32 from excessively increasing due to, for example, the switching element 43 being driven at a high frequency.

[0160] (1-15) As a configuration in which the cap cover part 140 is connected to the side surface of the cap 50 in a manner that allows heat transfer, the cap cover part 140 includes a through-hole 143 into which the cap 50 is press-fitted. With this configuration, heat from the semiconductor light-emitting element 32 is efficiently transferred from the cap 50 to the cap cover part 140. Therefore, it is possible to further suppress an excessive rise in the temperature of the semiconductor light-emitting element 32 due to, for example, the switching element 43 being driven at a high frequency.

[0161] (1-16) The inner surface of the through hole 143 is connected to the side surface of the cap 50 over the entire circumference so as to be able to transfer heat. With this configuration, the cap cover part 140 can transfer heat from the cap 50 over the entire circumference of the side surface of the cap 50, so that the heat of the semiconductor light emitting element 32 is efficiently transferred to the cap cover part 140. Therefore, it is possible to further suppress an excessive rise in the temperature of the semiconductor light emitting element 32 due to, for example, the switching element 43 being driven at a high frequency.

[0162] (1-17) The cap cover part 140 is in contact with the base 21. With this configuration, heat from the semiconductor light emitting element 32 is transferred from the base 21 to the cap cover part 140. In other words, the number of heat dissipation paths from the semiconductor light emitting element 32 to the cap cover part 140 is increased. This makes it possible to further prevent the temperature of the semiconductor light emitting element 32 from excessively increasing due to, for example, the switching element 43 being driven at a high frequency.

[0163] (1-18) The cap cover part 140 has a thickness TCC that is greater than the height dimension HCP of the cap 50. With this configuration, the cap cover part 140 can cover the side surface of the cap 50 over the entire height direction of the cap 50. This increases the area for transferring heat from the semiconductor light emitting element 32 from the cap 50 to the cap cover part 140, allowing efficient heat dissipation from the semiconductor light emitting element 32 to the cap cover part 140. Therefore, it is possible to further suppress an excessive rise in temperature of the semiconductor light emitting element 32 due to, for example, driving the switching element 43 at high frequency.

[0164] (1-19) The circuit board 120 is disposed adjacent to the cap cover portion 140. The lead pins 23A to 23D of the semiconductor light emitting device 10 are mounted on the end of the circuit board 120 adjacent to the cap cover portion 140.

[0165] This configuration allows the base 21 of the semiconductor light emitting device 10 and the circuit board 120 to be brought closer together, and the lead pins 23A to 23D can be mounted on the circuit board 120 near the base 21. This allows the lengths of the terminal portions 27A to 27D of the lead pins 23A to 23D to be shortened.

[0166] 22 to 25, a semiconductor light emitting device 10 according to a second embodiment will be described. The semiconductor light emitting device 10 according to this embodiment differs from the semiconductor light emitting device 10 according to the first embodiment mainly in the configuration of the heat sink 22, the configuration of the second substrate 41, and the mounting mode of the capacitor 44. In the following description, components common to the first embodiment are designated by the same reference numerals, and description thereof will be omitted.

[0167] FIG. 22 shows a perspective view of the interior of the semiconductor light-emitting device 10 of this embodiment. For ease of understanding, the cap 50 is omitted from the semiconductor light-emitting device 10 in FIG. 22. The connection configuration of the cap 50 and the wires W1 to W4 is the same as in the first embodiment. FIG. 23 shows an enlarged front view of the second substrate 41 and its surroundings as viewed from the y direction in FIG. 22. FIG. 24 shows the front view of the first substrate 31 and the second substrate 41. For ease of understanding, the semiconductor light-emitting element 32 and the drive circuit element 42 are indicated by two-dot chain lines in FIG. 24. FIG. 25 shows the rear view of the first substrate 31 and the second substrate 41. For convenience, the heat sink 22 is indicated by two-dot chain lines in FIG. 25.

[0168] 22 , the heat sink 22 includes a mounting surface 24 to which both the first substrate 31 and the second substrate 41 are attached. The mounting surface 24 is a flat surface along the xz plane. Therefore, the area of ​​the mounting surface 24 to which the first substrate 31 is attached is flush with the area of ​​the mounting surface 24 to which the second substrate 41 is attached.

[0169] In this embodiment, the second substrate 41 is attached to the mounting surface 24 closer to the tip surface 22a in the z direction. More specifically, when viewed from the y direction, the distance between the second substrate 41 and the tip surface 22a in the z direction is smaller than the distance between the second substrate 41 and the base surface 21s of the base 21 in the z direction.

[0170] 23 , the second substrate 41 includes second substrate side surfaces 41a and 41b facing opposite each other in the z direction. The second substrate side surface 41a is the substrate side surface of the second substrate 41 closer to the tip surface 22a, and the second substrate side surface 41b is the substrate side surface of the second substrate 41 opposite the tip surface 22a. The second substrate side surfaces 41a and 41b are flat surfaces along the xy plane. The second substrate side surfaces 41a and 41b are formed by the substrate side surfaces of the second base material 41A.

[0171] A recess 49 is formed at an end of the second substrate 41, recessed from the end. When viewed from the y direction, the recess 49 opens toward the tip surface 22a. More specifically, the recess 49 is recessed from the second substrate side surface 41a toward the second substrate side surface 41b. The recess 49 is formed in the center of the second substrate 41 in the x direction. A region RG is formed by the recess 49. The region RG is a region surrounded by the three second substrate side surfaces of the second substrate 41 that form the recess 49. As shown in FIG. 23 , when viewed from the y direction, the region RG has a rectangular shape with the x direction as the longitudinal direction and the z direction as the lateral direction.

[0172] 24, the depth HR of the recess 49 is equal to or greater than the size LZ of the first substrate 31 in the z direction. The size LZ of the first substrate 31 in the z direction is the size of the first substrate 31 in the short direction. The size LR of the recess 49 in the x direction is equal to or greater than the size LSX of the switching element 43 in the x direction (see FIG. 23). Here, the depth HR of the recess 49 corresponds to the length of the region RG in the short direction, and the size LR of the recess 49 in the x direction corresponds to the length of the region RG in the long direction.

[0173] The second substrate 41 has first surface side wiring 61 and second surface side wiring 62. The first surface side wiring 61 and the second surface side wiring 62 are formed on the second substrate surface 41s of the second substrate 41. The first surface side wiring 61 and the second surface side wiring 62 are formed of, for example, copper foil.

[0174] The first surface-side wiring 61 is formed closer to the second substrate side surface 41b than the recess 49. The first surface-side wiring 61 is rectangular in shape, with its longitudinal direction in the x direction and its lateral direction in the z direction when viewed from the y direction. The first surface-side wiring 61 is formed over most of the portion of the second substrate 41 closer to the second substrate side surface 41b than the recess 49.

[0175] Two second surface-side wirings 62 are formed on the second substrate 41, distributed on both sides of the recess 49 in the x direction. The two second surface-side wirings 62 are arranged closer to the second substrate side surface 41a than the first surface-side wirings 61. The two second surface-side wirings 62 are arranged spaced apart in the x direction while aligned with each other in the z direction. When viewed from the x direction, each second surface-side wiring 62 is arranged in a position overlapping the recess 49. When viewed from the y direction, each second surface-side wiring 62 has a rectangular shape with the x direction as its longitudinal direction and the z direction as its lateral direction. When viewed from the x direction, each second surface-side wiring 62 is arranged in a position partially overlapping with the first substrate 31. In this embodiment, each second surface-side wiring 62 is arranged shifted to the opposite side of the tip surface 22a with respect to the first substrate 31.

[0176] The second substrate 41 has a plurality of (16 in this embodiment) first through holes 63 and a plurality of (6 in this embodiment) second through holes 64. Each of the first through holes 63 and each of the second through holes 64 penetrates the second substrate 41 in its thickness direction (y direction). Each of the first through holes 63 and each of the second through holes 64 is formed from a conductive material. In one example, each of the first through holes 63 and each of the second through holes 64 is formed from a material containing Cu.

[0177] The multiple first through holes 63 are provided in the second substrate 41 closer to the second substrate side surface 41b than the recess 49 and in the center in the x direction. In this embodiment, the 16 first through holes 63 are arranged in a grid pattern of four in the x direction and four in the z direction. Each first through hole 63 is electrically connected to the first surface-side wiring 61.

[0178] A first heat dissipation material 65 is provided inside each first through hole 63. More specifically, the first heat dissipation material 65 is provided so as to fill the inside of each first through hole 63. The first heat dissipation material 65 is formed, for example, from a metal material. In one example, the first heat dissipation material 65 is formed from a material containing Cu. In other words, the first heat dissipation material 65 may be formed from the same material as the first through holes 63.

[0179] The multiple second through holes 64 are formed at positions overlapping the second surface-side wiring 62 when viewed from the y direction. The multiple second through holes 64 are formed on the second substrate 41 closer to the second substrate side surface 41 a than the first surface-side wiring 61. In this embodiment, three second through holes 64 are arranged on each side of the recess 49 in the x direction. The multiple second through holes 64 are aligned with each other in the z direction and spaced apart from each other in the x direction. Each second through hole 64 is electrically connected to the second surface-side wiring 62.

[0180] A second heat dissipation material 66 is provided inside each second through hole 64. More specifically, the second heat dissipation material 66 is provided so as to fill the inside of each second through hole 64. The second heat dissipation material 66 is formed, for example, from a metal material. In one example, the second heat dissipation material 66 is formed from a material containing Cu. In other words, the second heat dissipation material 66 may be formed from the same material as the second through holes 64.

[0181] The number of each of the first through holes 63 and the second through holes 64 can be changed as desired. The materials constituting the first heat dissipation material 65 and the second heat dissipation material 66 can be changed as desired. The first heat dissipation material 65 may be made of a material different from that of the first through holes 63. The second heat dissipation material 66 may be made of a material different from that of the second through holes 64. In one example, each of the first heat dissipation material 65 and the second heat dissipation material 66 may be made of an insulating material.

[0182] The second substrate 41 has a surface-side resist layer 67 that covers a portion of the first surface-side wiring 61 and a portion of the second surface-side wiring 62. The surface-side resist layer 67 is formed of an insulating material. The surface-side resist layer 67 has a switching element opening 67a, a plurality of (two in this embodiment) first capacitor openings 67b, a plurality of (two in this embodiment) second capacitor openings 67c, and a wire opening 67d. The switching element opening 67a, each second capacitor opening 67c, and wire opening 67d expose the first surface-side wiring 61 from the surface-side resist layer 67. Each first capacitor opening 67b exposes the second surface-side wiring 62 from the surface-side resist layer 67.

[0183] When viewed from the z direction, the switching element openings 67a are formed at positions overlapping the recesses 49. The switching element openings 67a expose the first through-holes 63 and the first heat dissipation materials 65.

[0184] The second capacitor openings 67c are formed on both sides of the switching element opening 67a in the x direction, and are spaced apart from each other in the x direction while being aligned with each other in the z direction. The two second capacitor openings 67c are positioned so as to overlap with the switching element openings 67a when viewed from the x direction.

[0185] The wire opening 67d is formed closer to the second substrate side surface 41b than the second capacitor opening 67c. The wire opening 67d is disposed on one side in the x direction with respect to the switching element opening 67a.

[0186] The first capacitor openings 67b are formed closer to the second substrate side surface 41a than the switching element openings 67a. The first capacitor openings 67b are formed dispersedly on both sides of the recess 49 in the x direction. The two first capacitor openings 67b are formed spaced apart from each other in the x direction while being aligned with each other in the z direction. The two first capacitor openings 67b are formed at positions aligned with the corresponding four second capacitor openings 67c in the x direction.

[0187] The switching element 43 is disposed in the switching element opening 67 a. More specifically, the switching element 43 is bonded to the first surface side wiring 61 exposed by the switching element opening 67 a with a conductive bonding material. As a result, the drain electrode 43D (see FIG. 8 ) of the switching element 43 is electrically connected to the first surface side wiring 61.

[0188] The four capacitors 44 are arranged two on each side of the recess 49 in the x direction. The first electrode 44A of each capacitor 44 is positioned to overlap the first capacitor opening 67b when viewed from the y direction. The first electrode 44A is bonded to the second surface-side wiring 62 exposed by the first capacitor opening 67b with a conductive adhesive. The first electrode 44A is electrically connected to the second surface-side wiring 62. The second electrode 44B of each capacitor 44 is positioned to overlap the second capacitor opening 67c when viewed from the y direction. The second electrode 44B is bonded to the first surface-side wiring 61 exposed by the second capacitor opening 67c with a conductive adhesive. The second electrode 44B is electrically connected to the first surface-side wiring 61. It can also be said that the second electrode 44B is electrically connected to the drain electrode 43D of the switching element 43. In this manner, both the first electrode 44 A and the second electrode 44 B of each capacitor 44 are mounted on the second substrate 41 .

[0189] The layout of the switching element 43 and the four capacitors 44 is the same as in the first embodiment. The circuit configuration of the semiconductor light emitting device 10 of this embodiment is the same as in the first embodiment.

[0190] As shown in FIG. 25 , the second substrate 41 has two rear-side wirings 68 and a first rear-side resist layer 69A and a second rear-side resist layer 69B. The two rear-side wirings 68 are formed on both sides of the recess 49 of the second substrate 41 in the x direction. When viewed from the y direction, each rear-side wiring 68 is arranged in a position overlapping with the second surface-side wiring 62 (see FIG. 24 ) corresponding to the rear-side wiring 68. The two rear-side wirings 68 are arranged spaced apart from each other in the x direction while being aligned with each other in the z direction. When viewed from the x direction, the rear-side wirings 68 are arranged in a position overlapping with the recess 49. When viewed from the y direction, the rear-side wirings 68 are rectangular with the x direction as the longitudinal direction and the z direction as the lateral direction.

[0191] Each back surface side wiring 68 is electrically connected to a plurality of second through holes 64. Therefore, the back surface side wiring 68 and the second front surface side wiring 62 that are arranged in positions that overlap each other when viewed from the y direction are electrically connected by the plurality of second through holes 64.

[0192] The first back-surface-side resist layer 69A is formed closer to the second substrate side surface 41b than the recess 49. The first back-surface-side resist layer 69A has a rectangular shape with its longitudinal direction in the x direction and its lateral direction in the z direction when viewed from the y direction. The first back-surface-side resist layer 69A is formed over most of the portion of the second substrate 41 closer to the second substrate side surface 41b than the recess 49. The first back-surface-side resist layer 69A is positioned so as to overlap the first surface-side wiring 61 when viewed from the y direction. Therefore, the first back-surface-side resist layer 69A covers the multiple first through-holes 63 and the multiple first heat dissipation materials 65.

[0193] Two second rear-surface-side resist layers 69B are provided to cover the two rear-surface-side wirings 68, respectively. The second rear-surface-side resist layer 69B has openings 69BA. The openings 69BA expose the rear-surface-side wirings 68, the second through-holes 64, and the second heat dissipation material 66. As a result, when the second substrate 41 is attached to the heat sink 22, the rear-surface-side wirings 68 are electrically connected to the heat sink 22 via the conductive adhesive. In other words, the second surface-side wirings 62 are electrically connected to the heat sink 22 via the rear-surface-side wirings 68 and the second through-holes 64. Therefore, the first electrode 44A of the capacitor 44 in FIG. 24 is electrically connected to the heat sink 22. Therefore, it can be said that the first electrode 44A is electrically connected to the semiconductor light-emitting element 32 via the second through-holes 64, the rear-surface-side wirings 68, and the first substrate 31. In this way, the rear-surface-side wirings 68 correspond to "pads electrically connected to the heat sink."

[0194] As shown in FIG. 23 , when viewed from the y direction, the light-emitting unit 30 is disposed such that at least a portion thereof extends into region RG while being spaced apart from the second substrate 41. Therefore, when viewed from the y direction, it can be said that the first substrate 31 is disposed such that at least a portion thereof extends into region RG while being spaced apart from the second substrate 41. In this embodiment, when viewed from the y direction, a portion of the light-emitting unit 30 extends into region RG. Therefore, in this embodiment, a portion of the first substrate 31 extends into region RG. The first substrate 31 includes a portion that protrudes toward the tip surface 22a of the heat sink 22 relative to the second substrate side surface 41a of the second substrate 41. The distance G1 between the first substrate 31 and the tip surface 22a in the z direction is smaller than the distance G2 between the first substrate 31 and the bottom surface of the recess 49 of the second substrate 41 in the z direction. Note that the configurations of the first substrate 31 and the semiconductor light-emitting element 32 are the same as those in the first embodiment. For this reason, the cathode electrode 37 (see FIG. 8) of the semiconductor light emitting element 32 is electrically connected to the heat sink 22. The positional relationship of the first substrate 31 and the semiconductor light emitting element 32 with respect to the switching element 43 and the capacitor 44 is the same as in the first embodiment.

[0195] Since the semiconductor light emitting element 32 is disposed at the same position as the switching element 43 in the x direction, the semiconductor light emitting element 32 is disposed at a position overlapping the switching element 43 when viewed from the z direction.

[0196] [Effects] According to the semiconductor light emitting device 10 of this embodiment, in addition to the effects (1-1) to (1-4) and (1-9) to (1-13) of the first embodiment, the following effects can be obtained.

[0197] (2-1) A recess 49 recessed from the end is formed at the end of the second substrate 41. The first substrate 31 is arranged so that at least a portion of the first substrate 31 enters the region RG formed by the recess 49 while being spaced apart from the second substrate 41.

[0198] According to this configuration, compared to when the first substrate 31 is positioned closer to the tip surface 22a of the heat sink 22 than the second substrate side surface 41a of the second substrate 41, it is possible to shorten the conductive path between the semiconductor light-emitting element 32 mounted on the first substrate 31 and the first electrode 44A of the capacitor 44 mounted on the second substrate 41. Furthermore, since the semiconductor light-emitting element 32 and the switching element 43 can be brought closer to each other, the wire W1 connecting the semiconductor light-emitting element 32 and the switching element 43 can be shortened.

[0199] (2-2) The drive circuit element 42 includes a capacitor 44 having a first electrode 44A and a second electrode 44B. Both the first electrode 44A and the second electrode 44B of the capacitor 44 are mounted on the second substrate 41. The second substrate 41 includes a second through-hole 64 that electrically connects the first electrode 44A of the capacitor 44 and the heat sink 22.

[0200] This configuration shortens the conductive path between the first electrode 44A of the capacitor 44 and the heat sink 22 compared to a configuration in which the first electrode 44A and the heat sink 22 are electrically connected by, for example, a wire. In addition, the diameter of the second through hole 64 can be easily made larger than the diameter of the wire. Therefore, by making the diameter of the second through hole 64 larger than the diameter of the wire, inductance can be reduced.

[0201] 26 to 29, a semiconductor light emitting device 10 according to a third embodiment will be described. The semiconductor light emitting device 10 according to this embodiment differs from the semiconductor light emitting device 10 according to the first embodiment mainly in the configuration of the second substrate 41 and the mounting mode of the capacitor 44. In the following description, components common to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0202] FIG. 26 shows a perspective view of the interior of the semiconductor light-emitting device 10 of this embodiment. For ease of understanding, the cap 50 is omitted from the semiconductor light-emitting device 10 in FIG. 26. The connection configuration of the cap 50 and the wires W1 to W4 is the same as in the first embodiment. FIG. 27 shows an enlarged front view of the second substrate 41 and its surroundings as viewed from the y direction in FIG. 26. FIG. 26 shows the front view of the first substrate 31 and the second substrate 41. For ease of understanding, the semiconductor light-emitting element 32 and the drive circuit element 42 are indicated by two-dot chain lines in FIG. 27. FIG. 28 shows the rear view of the first substrate 31 and the second substrate 41. For convenience, the heat sink 22 is indicated by two-dot chain lines in FIG. 28.

[0203] 26 , a first electrode 44A and a second electrode 44B of each capacitor 44 are mounted on a second substrate 41 of the drive unit 40. The mounting structure of the first electrode 44A and the second electrode 44B of each capacitor 44 on the second substrate 41 is the same as in the second embodiment. The second substrate 41 is electrically connected to the heat sink 22 by, for example, a wire W5.

[0204] 27 , the first electrode 44A of each capacitor 44 is disposed closer to the switching element 43 than the first mounting surface 24A of the heat sink 22. In other words, the first electrode 44A is disposed closer to the switching element 43 than the first substrate 31 (semiconductor light-emitting element 32). The second electrode 44B of each capacitor 44 is disposed in a position overlapping the switching element 43 when viewed from the x direction. In this way, each capacitor 44 is disposed entirely closer to the switching element 43 than the semiconductor light-emitting element 32. In other words, the semiconductor light-emitting element 32 is disposed entirely closer to the tip surface 22 a of the heat sink 22 than each capacitor 44.

[0205] 28 , the second substrate 41 has surface-side wiring 71 and connection wiring 72. The surface-side wiring 71 and connection wiring 72 are formed on the second substrate surface 41s of the second substrate 41. Both the surface-side wiring 71 and the connection wiring 72 are formed of, for example, copper foil.

[0206] The surface-side wiring 71 is disposed closer to the base 21 (see FIG. 26 ) of the second substrate 41. When viewed from the y direction, the surface-side wiring 71 has a rectangular shape with its longitudinal direction in the x direction and its lateral direction in the z direction.

[0207] The connection wiring 72 is arranged on the second substrate 41 closer to the first mounting surface 24A than the surface-side wiring 71. The connection wiring 72 is arranged at a distance from the surface-side wiring 71 in the z direction. When viewed from the y direction, the connection wiring 72 has a rectangular shape with its longitudinal direction in the x direction and its lateral direction in the z direction. The size of the connection wiring 72 in the x direction is, for example, equal to the size of the surface-side wiring 71 in the x direction. The size of the connection wiring 72 in the z direction is smaller than the size of the surface-side wiring 71 in the z direction.

[0208] The second substrate 41 has a plurality of (16 in this embodiment) through holes 73. Each through hole 73 penetrates the second substrate 41 in its thickness direction (y direction). The through holes 73 are made of a conductive material. In one example, each through hole 73 is made of a material containing Cu.

[0209] The through holes 73 are provided in the second substrate 41 closer to the base 21 (see FIG. 26 ) than the connection wiring 72 and in the center in the x direction. In this embodiment, the 16 through holes 73 are arranged in a grid pattern of four in the x direction and four in the z direction. Each through hole 73 is electrically connected to the surface-side wiring 71.

[0210] A heat dissipation material 74 is provided inside each through hole 73. More specifically, the heat dissipation material 74 is provided so as to fill the inside of each through hole 73. The heat dissipation material 74 is formed, for example, from a metal material. In one example, the heat dissipation material 74 is formed from a material containing Cu. In other words, the heat dissipation material 74 may be formed from the same material as the through holes 73.

[0211] The material constituting the heat dissipation material 74 can be changed as desired. The heat dissipation material 74 may be made of a material different from that of the through holes 73. In one example, the heat dissipation material 74 may be made of an insulating material.

[0212] The second substrate 41 has a surface-side resist layer 75 that covers a portion of the surface-side wiring 71 and a portion of the connection wiring 72. The surface-side resist layer 75 is formed of an insulating material. The surface-side resist layer 75 has a switching element opening 75a, a plurality of (two in this embodiment) first capacitor openings 75b, a plurality of (two in this embodiment) second capacitor openings 75c, a first wire opening 75d, and a second wire opening 75e. The switching element opening 75a, each second capacitor opening 75c, and each first wire opening 75d expose the surface-side wiring 71 from the surface-side resist layer 75. The first capacitor openings 75b and second wire openings 75e expose the connection wiring 72 from the surface-side resist layer 75.

[0213] When viewed from the z direction, the switching element opening 75 a is formed at a position overlapping the center in the x direction of the surface-side wiring 71. The switching element opening 75 a exposes the surface-side wiring 71, the plurality of through holes 73, and the heat dissipation material 74.

[0214] The two second capacitor openings 75c are formed on both sides of the switching element opening 75a in the x direction, spaced apart from each other in the x direction while being aligned with each other in the z direction. Each second capacitor opening 75c is formed at one of both ends of the front-side wiring 71 in the z direction, closer to the connection wiring 72.

[0215] The first wire opening 75d is formed closer to the base 21 (see FIG. 26) than the second capacitor opening 75c. The first wire opening 75d is disposed on one side in the x direction with respect to the switching element opening 75a.

[0216] The two first capacitor openings 75b are formed closer to the first mounting surface 24A than the switching element openings 75a. The two first capacitor openings 75b are arranged closer to the first mounting surface 24A than the second capacitor openings 75c. The two first capacitor openings 75b are formed dispersedly on both sides of the switching element opening 75a in the x direction. The two first capacitor openings 75b are formed spaced apart from each other in the x direction while being aligned with each other in the z direction. The two first capacitor openings 75b are formed in positions aligned with the corresponding two second capacitor openings 75c in the x direction.

[0217] The second wire opening 75e is formed at a position overlapping the center of the connection wiring 72 in the x direction. When viewed from the y direction, the second wire opening 75e has a rectangular shape with the x direction as its longitudinal direction and the z direction as its transverse direction. The second wire opening 75e is formed between two first capacitor openings 75b that are spaced apart from each other in the x direction. In this embodiment, the second wire opening 75e is positioned so as to partially overlap the first capacitor opening 75b when viewed from the x direction. More specifically, the second wire opening 75e is shifted toward the first mounting surface 24A relative to the first capacitor opening 75b in the z direction. A portion of the second wire opening 75e near the switching element opening 75a overlaps the first capacitor opening 75b when viewed from the x direction. The size of the second wire opening 75e in the x direction is larger than the size of the semiconductor light emitting element 32 (first substrate 31) in the x direction.

[0218] 27 , the switching element 43 is disposed in the switching element opening 75 a. More specifically, the switching element 43 is bonded to the surface-side wiring 71 exposed by the switching element opening 75 a with a conductive bonding material. As a result, the drain electrode 43D (see FIG. 8 ) of the switching element 43 is electrically connected to the surface-side wiring 71.

[0219] The four capacitors 44 are arranged two on each side of the switching element 43 in the x direction. The first electrode 44A of each capacitor 44 is positioned to overlap the first capacitor opening 75b when viewed from the y direction. The first electrode 44A is bonded with a conductive adhesive to the connection wiring 72 exposed by the first capacitor opening 75b. The first electrode 44A is electrically connected to the connection wiring 72. The second electrode 44B of each capacitor 44 is positioned to overlap the second capacitor opening 75c when viewed from the y direction. The second electrode 44B is bonded with a conductive adhesive to the surface-side wiring 71 exposed by the second capacitor opening 75c. The second electrode 44B is electrically connected to the surface-side wiring 71. The second electrode 44B can also be said to be electrically connected to the drain electrode 43D of the switching element 43. The relative positions of the switching element 43 and the four capacitors 44 are the same as those in the first embodiment.

[0220] The first mounting surface 24A of the heat sink 22 and the connection wiring 72 are connected by wires W5. Specifically, a first end of the wire W5 is bonded to the first mounting surface 24A, and a second end of the wire W5 is bonded to the connection wiring 72 exposed by the second wire opening 75e in the front-side resist layer 75. The wires W5 are arranged on both sides in the x direction of the four wires W1 connecting the semiconductor light-emitting element 32 and the switching element 43. When viewed from the y direction, the wires W5 are arranged on both sides of the semiconductor light-emitting element 32 in the x direction and spaced apart from the semiconductor light-emitting element 32. When viewed from the y direction, the wires W5 are arranged between the semiconductor light-emitting element 32 (first substrate 31) and the capacitor 44 in the x direction. The number of wires W5 can be changed as desired.

[0221] 29 , the second substrate 41 has a first rear surface-side resist layer 76 and a second rear surface-side resist layer 77. Both the first rear surface-side resist layer 76 and the second rear surface-side resist layer 77 are formed on the second substrate rear surface 41r. Both the first rear surface-side resist layer 76 and the second rear surface-side resist layer 77 are formed of an insulating material.

[0222] The first back-side resist layer 76 is disposed on the second substrate 41 closer to the base 21 (see FIG. 26 ). When viewed from the y direction, the first back-side resist layer 76 has a rectangular shape with the x direction as its longitudinal direction and the z direction as its lateral direction. When viewed from the y direction, the first back-side resist layer 76 is disposed in a position overlapping the surface-side wiring 71 (see FIG. 28 ). When viewed from the y direction, the size of the first back-side resist layer 76 is, for example, the same as the size of the surface-side wiring 71. The first back-side resist layer 76 covers the multiple through-holes 73. Therefore, the first back-side resist layer 76 insulates the multiple through-holes 73 from the heat sink 22.

[0223] The second back-side resist layer 77 is disposed on the second substrate 41 closer to the tip surface 22a of the heat sink 22 than the front-side wiring 71. The second back-side resist layer 77 is disposed spaced apart from the first back-side resist layer 76 in the z direction. When viewed from the y direction, the second back-side resist layer 77 is disposed at a position overlapping the connection wiring 72 (see FIG. 28 ). The size of the second back-side resist layer 77 in the z direction is smaller than the size of the first back-side resist layer 76 in the z direction. Note that the first back-side resist layer 76 and the second back-side resist layer 77 may be configured as an integrally formed back-side resist layer. In this case, the back-side resist layer may be formed, for example, over the entire second substrate back surface 41r of the second substrate 41.

[0224] As shown in Figure 27, the light-emitting unit 30 is attached to the first attachment surface 24A. The attachment position of the light-emitting unit 30 relative to the heat sink 22 is the same as in the first embodiment. The configuration of the light-emitting unit 30 is the same as in the first embodiment. That is, the cathode electrode 37 (see Figure 8) of the semiconductor light-emitting element 32 is electrically connected to the heat sink 22. Therefore, the first electrode 44A of the capacitor 44 is electrically connected to the cathode electrode 37 via the connection wiring 72, the wire W5, and the heat sink 22. The circuit configuration of the semiconductor light-emitting device 10 of this embodiment is the same as in the first embodiment.

[0225] In the present embodiment, the connection wiring 72 and the first mounting surface 24A of the heat sink 22 are connected by the wire W5, but the electrical connection between the connection wiring 72 and the first mounting surface 24A is not limited to this. For example, the connection wiring 72 and the first mounting surface 24A may be electrically connected by a connecting member such as a clip or a ribbon instead of the wire W5.

[0226] [Effects] According to the semiconductor light emitting device 10 of this embodiment, in addition to the effects (1-1) to (1-5) and (1-9) to (1-13) of the first embodiment, the following effects can be obtained.

[0227] (3-1) The drive circuit element 42 includes a switching element 43 and a capacitor 44 having a first electrode 44A and a second electrode 44B. The semiconductor light-emitting element 32 and the switching element 43 are arranged spaced apart from each other in the z direction, which is the direction in which the heat sink 22 is erected. A connection wiring 72 for electrically connecting the second substrate 41 to the heat sink 22 is provided in a portion of the second substrate 41 between the semiconductor light-emitting element 32 and the switching element 43 in the z direction. The first electrode 44A of the capacitor 44 is mounted on the connection wiring 72. The connection wiring 72 and the heat sink 22 are connected by a wire W5.

[0228] With this configuration, the conductive path between the first electrode 44A and the semiconductor light emitting element 32 can be shortened compared to when a through hole is provided in the second substrate 41 to electrically connect the second mounting surface 24B of the heat sink 22 and the first electrode 44A of the capacitor 44. In addition, the connection structure between the connection wiring 72 and the heat sink 22 can be simplified.

[0229] 30 and 31 , a semiconductor light emitting device 10 according to a fourth embodiment will be described. The semiconductor light emitting device 10 according to this embodiment differs from the semiconductor light emitting device 10 according to the first embodiment mainly in that the first substrate 31 is omitted. In the following description, components common to the first embodiment are designated by the same reference numerals, and descriptions thereof will be omitted.

[0230] Fig. 30 shows a perspective view of the interior of the semiconductor light-emitting device 10 of this embodiment. For ease of understanding, the cap 50 is omitted from the semiconductor light-emitting device 10 in Fig. 30. The connection configuration between the cap 50 and the wires W1 to W4 is the same as in the first embodiment. Fig. 31 shows a cross-sectional structure of the heat sink 22, the light-emitting unit 30, and the drive unit 40 in the semiconductor light-emitting device 10 of Fig. 30 taken along the yz plane. For ease of understanding, the wires W1 to W4 are omitted from Fig. 31.

[0231] 30 and 31 , the semiconductor light emitting element 32 is directly attached to the heat sink 22 at a position different from the second substrate 41. More specifically, the semiconductor light emitting element 32 is directly attached to the first mounting surface 24A. Specifically, the semiconductor light emitting element 32 is bonded to the first mounting surface 24A of the heat sink 22 with a conductive bonding material, that is, the semiconductor light emitting element 32 is mounted on the first mounting surface 24A. Therefore, the cathode electrode 37 of the semiconductor light emitting element 32 is electrically connected to the heat sink 22. Here, in this embodiment, the second substrate 41 corresponds to the "substrate attached to the heat sink."

[0232] 31 , the height HL1 of the semiconductor light emitting element 32 from the first mounting surface 24A is less than the height HC1 of the capacitor 44 from the first mounting surface 24A. The height HL1 of the semiconductor light emitting element 32 from the first mounting surface 24A is less than the height HS of the switching element 43 from the second substrate surface 41 s of the second substrate 41.

[0233] In this embodiment, the heat sink 22 is formed of a material whose linear expansion coefficient is closer to that of the semiconductor light emitting element 32 than in the first embodiment. In this case, the heat sink 22 may be formed of a material different from that of the base 21. The heat sink 22 is formed of a material whose linear expansion coefficient is smaller than that of Cu. In one example, the heat sink 22 may be formed of a material containing Fe. The heat sink 22 may be formed of, for example, Fe or an alloy of Fe and nickel (Ni). The material constituting the heat sink 22 can be changed as desired.

[0234] [Effects] In addition to the effects (1-5) to (1-10) of the first embodiment, the semiconductor light emitting device 10 of this embodiment has the following effects.

[0235] (4-1) The semiconductor light-emitting device 10 comprises a base 21, a conductive heat sink 22 standing on the base 21, a second substrate 41 attached to the heat sink 22, a semiconductor light-emitting element 32 attached directly to the heat sink 22 at a position different from the second substrate 41, and a drive circuit element 42 at least partially mounted on the second substrate 41 and driving the semiconductor light-emitting element 32.

[0236] According to this configuration, the semiconductor light emitting element 32 and the second substrate 41 on which the drive circuit element 42 is mounted are attached to the heat sink 22 so as to be spaced apart from each other, so that the heat of the semiconductor light emitting element 32 is easily transferred to the heat sink 22 but is less likely to be transferred to the second substrate 41. Therefore, the heat of the semiconductor light emitting element 32 can be prevented from affecting the drive circuit element 42.

[0237] In addition, the semiconductor light emitting element 32 is attached directly to the heat sink 22 without the first substrate 31 (see FIG. 2) in between. This makes it easier for heat from the semiconductor light emitting element 32 to be transferred to the heat sink 22.

[0238] (4-2) The heat sink 22 includes a second mounting surface 24B to which the second substrate 41 is attached, and a first mounting surface 24A formed closer to the tip of the heat sink 22 than the second mounting surface 24B and on which the semiconductor light emitting element 32 is mounted. The first mounting surface 24A protrudes from the second mounting surface 24B in the y direction, which is the thickness direction perpendicular to the erection direction (z direction) of the heat sink 22. The first mounting surface 24A is located closer to the second substrate surface 41s of the second substrate 41 than the second mounting surface 24B.

[0239] With this configuration, the position of the semiconductor light emitting element 32 in the y direction relative to the second mounting surface 24B of the heat sink 22 and the position of the switching element 43 in the y direction relative to the second mounting surface 24B are close to each other. This allows the wire W1 connecting the semiconductor light emitting element 32 and the switching element 43 to be shortened.

[0240] Fifth Embodiment A semiconductor light emitting device 10 according to a fifth embodiment will be described with reference to Figures 32 and 33. The semiconductor light emitting device 10 according to this embodiment differs from the semiconductor light emitting device 10 according to the second embodiment mainly in that the first substrate 31 is omitted. In the following description, components common to the first embodiment are designated by the same reference numerals, and descriptions thereof will be omitted.

[0241] Fig. 32 shows a perspective view of the interior of the semiconductor light-emitting device 10 of this embodiment. For ease of understanding, the cap 50 is omitted from the semiconductor light-emitting device 10 in Fig. 32. The connection configuration between the cap 50 and the wires W1 to W4 is the same as in the first embodiment. Fig. 33 shows a cross-sectional structure of the heat sink 22, the light-emitting unit 30, and the drive unit 40 in the semiconductor light-emitting device 10 of Fig. 32, cut along the yz plane. For ease of understanding, the wires W1 to W4 are omitted from Fig. 33.

[0242] 32 and 33 , the semiconductor light emitting element 32 is directly attached to the heat sink 22 at a position different from the second substrate 41. More specifically, the semiconductor light emitting element 32 is bonded to the attachment surface 24 of the heat sink 22 with a conductive bonding material. In other words, the semiconductor light emitting element 32 is mounted on the attachment surface 24. Therefore, the cathode electrode 37 of the semiconductor light emitting element 32 is electrically connected to the heat sink 22. Here, in this embodiment, the second substrate 41 corresponds to the "substrate attached to the heat sink."

[0243] The semiconductor light emitting element 32 is disposed so that at least a portion thereof extends into the region RG while being separated from the second substrate 41. In this embodiment, a portion of the semiconductor light emitting element 32 extends into the region RG.

[0244] 33 , the height HL2 of the semiconductor light emitting element 32 from the mounting surface 24 is less than the height HB of the second substrate 41 from the mounting surface 24. Therefore, the semiconductor light emitting element 32 is disposed closer to the mounting surface 24 than the switching element 43 and the capacitor 44. The height HL2 of the semiconductor light emitting element 32 from the mounting surface 24 is less than the height HC2 of the capacitor 44 from the second substrate surface 41 s of the second substrate 41. The height HL2 of the semiconductor light emitting element 32 from the mounting surface 24 is less than the height HS of the switching element 43 from the second substrate surface 41 s of the second substrate 41.

[0245] In this embodiment, the heat sink 22 is formed of a material whose linear expansion coefficient is closer to that of the semiconductor light emitting element 32 than in the second embodiment. In this case, the heat sink 22 may be formed of a material different from that of the base 21. The heat sink 22 is formed of a material whose linear expansion coefficient is smaller than that of Cu. In one example, the heat sink 22 may be formed of a material containing Fe. The heat sink 22 may be formed of, for example, Fe or an alloy of Fe and nickel (Ni). Note that the material constituting the heat sink 22 can be changed as desired. According to the semiconductor light emitting device 10 of this embodiment, the same effect as that of (4-1) of the fourth embodiment can be obtained.

[0246] 34 and 35 , a semiconductor light emitting device 10 according to a sixth embodiment will be described. The semiconductor light emitting device 10 according to this embodiment differs from the semiconductor light emitting device 10 according to the third embodiment mainly in that the first substrate 31 is omitted. In the following description, components common to the first embodiment are designated by the same reference numerals, and description thereof will be omitted.

[0247] Fig. 34 shows a perspective view of the interior of the semiconductor light-emitting device 10 of this embodiment. For ease of understanding, the cap 50 is omitted from the semiconductor light-emitting device 10 in Fig. 34. The connection configuration between the cap 50 and the wires W1 to W5 is the same as in the third embodiment. Fig. 35 shows a cross-sectional structure of the heat sink 22, the light-emitting unit 30, and the drive unit 40 in the semiconductor light-emitting device 10 of Fig. 34 taken along the yz plane. For ease of understanding, the wires W1 to W5 are omitted from Fig. 35.

[0248] 34 and 35 , the semiconductor light emitting element 32 is directly attached to the heat sink 22 at a position different from the second substrate 41. More specifically, the semiconductor light emitting element 32 is directly attached to the first mounting surface 24A. Specifically, the semiconductor light emitting element 32 is bonded to the first mounting surface 24A of the heat sink 22 with a conductive bonding material. In other words, the semiconductor light emitting element 32 is mounted on the first mounting surface 24A. Therefore, the cathode electrode 37 of the semiconductor light emitting element 32 is electrically connected to the heat sink 22. Here, in this embodiment, the second substrate 41 corresponds to the "substrate attached to the heat sink."

[0249] 35 , the height HL1 of the semiconductor light emitting element 32 from the first mounting surface 24A is less than the height HC2 of the capacitor 44 from the second substrate surface 41 s of the second substrate 41. The height HL1 of the semiconductor light emitting element 32 from the first mounting surface 24A is less than the height HS of the switching element 43 from the second substrate surface 41 s of the second substrate 41.

[0250] In this embodiment, the heat sink 22 is formed of a material whose linear expansion coefficient is closer to that of the semiconductor light emitting element 32 than in the third embodiment. In this case, the heat sink 22 may be formed of a material different from that of the base 21. The heat sink 22 is formed of a material whose linear expansion coefficient is smaller than that of Cu. In one example, the heat sink 22 may be formed of a material containing Fe. The heat sink 22 may be formed of, for example, Fe or an alloy of Fe and nickel (Ni). Note that the material constituting the heat sink 22 can be changed as desired. According to the semiconductor light emitting device 10 of this embodiment, the same effect as that of (4-1) of the fourth embodiment can be obtained.

[0251] <Modifications> The above-described embodiments can be modified as follows: Furthermore, the above-described embodiments and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0252] [Modification of Heat Sink] In the first, third, fourth, and sixth embodiments, a gap is formed between the protrusion 26 of the heat sink 22 and the second substrate 41 in the z direction, but this is not limited to this. The second substrate 41 may be disposed so as to contact the protrusion 26 in the z direction. This configuration can reduce the distance between the semiconductor light emitting element 32 and the switching element 43 when viewed from the y direction. This allows the length of the wire W1 connecting the anode electrode 36 of the semiconductor light emitting element 32 and the source electrode 43S of the switching element 43 to be shortened.

[0253] In the first, third, fourth, and sixth embodiments, the position of the first mounting surface 24A of the heat sink 22 relative to the second mounting surface 24B in the y direction can be changed as desired. The position of the first mounting surface 24A relative to the second mounting surface 24B in the y direction may be different from the position of the second substrate surface 41s of the second substrate 41 relative to the second mounting surface 24B in the y direction. In other words, the first mounting surface 24A may be positioned closer to the second mounting surface 24B than the second substrate surface 41s in the y direction. Furthermore, the first mounting surface 24A may be positioned farther away from the second mounting surface 24B than the second substrate surface 41s in the y direction.

[0254] In the first, third, fourth, and sixth embodiments, the first mounting surface 24A is configured as a flat surface in which the first region where the light-emitting unit 30 is mounted and the second region where the capacitor 44 is mounted are flush with each other. However, this is not limited to this. The position of the first region in the y direction relative to the second mounting surface 24B and the position of the second region in the y direction relative to the second mounting surface 24B may be different from each other. The first region may be positioned closer to the second mounting surface 24B than the second region in the y direction. In this case, the position of the second region in the y direction relative to the second mounting surface 24B may be the same as the position of the second substrate surface 41s of the second substrate 41 in the y direction relative to the second mounting surface 24B.

[0255] In the third and sixth embodiments, the protrusion 26 may be omitted from the heat sink 22. That is, the heat sink 22 of the second and fifth embodiments may be used. In the second and fifth embodiments, the configuration of the mounting surface 24 of the heat sink 22 may be changed as desired. In one example, the mounting surface 24 includes a first region where the light-emitting unit 30 is mounted and a second region where the drive unit 40 is mounted. The first region may protrude in the y direction relative to the second region. That is, the first region may be located closer to the second substrate surface 41s of the second substrate 41 than the second region.

[0256] [Modifications of the First and Second Substrates] In the first embodiment, the length of the first substrate 31 in the x direction can be changed as desired. In one example, as shown in FIG. 36 , the first substrate 31 may extend to a position overlapping each capacitor 44 when viewed from the z direction. In this case, for example, the protrusion 26 (see FIG. 7 ) may be omitted from the heat sink 22. The heat sink 22 includes the mounting surface 24 as in the second embodiment. Both the first substrate 31 and the second substrate 41 are mounted to the mounting surface 24. In this case, for example, the position of the first substrate surface 31 s of the first substrate 31 relative to the mounting surface 24 in the y direction may be the same as the position of the second substrate surface 41 s of the second substrate 41 relative to the mounting surface 24. The first electrode 44A of each capacitor 44 is mounted on the first substrate surface 31 s of the first substrate 31. The second electrode 44B of each capacitor 44 is mounted on the second substrate surface 41 s of the second substrate 41.

[0257] In the third embodiment, the configuration of the connection wiring 72 can be changed as desired. For example, the connection wiring 72 may include a first wiring electrically connected to the first electrodes 44A of two capacitors 44 arranged on one side of the switching element 43 in the x direction, and a second wiring electrically connected to the first electrodes 44A of two capacitors 44 arranged on the other side of the switching element 43 in the x direction. The first wiring and the second wiring are arranged spaced apart from each other in the x direction. A plurality of wires W5 are provided so as to be connected to each of the first wiring and the second wiring.

[0258] In the third embodiment, the configuration of the front-side resist layer 75 can be changed as desired. For example, when viewed from the y direction, the front-side resist layer 75 may be configured to cover a region of the connection wiring 72 that overlaps with the wire W1 that connects the semiconductor light-emitting element 32 and the switching element 43. In other words, the second wire opening 75e only needs to be open in a region to which the wire W5 can be connected.

[0259] In the first to third embodiments, the first substrate 31 may extend to a position where it overlaps with at least one of the plurality of capacitors 44 when viewed from the z direction. In the first to third embodiments, the materials constituting the first substrate 31 and the second substrate 41 may each be changed as desired. In one example, the second substrate 41 may be made of a material with high thermal conductivity, such as alumina. In this case, the thermal conductivity of the first substrate 31 may be equal to the thermal conductivity of the second substrate 41.

[0260] The first substrate 31 may be a glass epoxy substrate, similar to the second substrate 41. In this case, the first substrate 31 may have through holes 34 and a heat dissipation material 35. The through holes 34 and the heat dissipation material 35 allow the heat from the semiconductor light emitting element 32 to be more easily transferred to the heat sink 22 than to the second substrate 41. Therefore, the effect of the heat from the semiconductor light emitting element 32 on the drive circuit element 42 can be reduced.

[0261] In the first to third embodiments, the through-holes 47 and the heat dissipation material 48 may be omitted from the second substrate 41. In this case, the rear surface-side resist layer 46r (the first rear surface-side resist layers 69A, 76 and the second rear surface-side resist layers 69B, 77) may be omitted from the second substrate 41.

[0262] In the second and fifth embodiments, the recess 49 may be omitted from the second substrate 41. That is, the second substrate 41 may have a rectangular shape with the x direction as the longitudinal direction and the z direction as the lateral direction when viewed from the y direction. In this case, the light-emitting unit 30 is disposed closer to the tip surface 22 a of the heat sink 22 than the second substrate 41.

[0263] [Modifications of the Drive Circuit Element] In each embodiment, the configuration of the drive circuit element 42 can be modified as desired. For example, the number of capacitors 44 may be two, or five or more. Also, either the capacitor 44 or the switching element 43 may be omitted. For example, the drive circuit element 42 includes the switching element 43. The capacitor 44 is provided outside the semiconductor light emitting device 10.

[0264] In each embodiment, the capacitor 44 may be disposed on one side in the x direction of the switching element 43. In each embodiment, a lateral MOSFET may be used as the switching element 43. In this case, a source electrode 43S, a drain electrode 43D, and a gate electrode 43G are formed on a switching element surface 43s of the switching element 43.

[0265] In each embodiment, the drive circuit element 42 may include at least one of the diode D and the resistor R of the laser system LS. In this case, if the drive circuit element 42 includes the diode D, the diode D may be mounted on, for example, the second substrate surface 41 s of the second substrate 41. If the drive circuit element 42 includes the resistor R, the resistor R may be mounted on, for example, the second substrate surface 41 s of the second substrate 41. If the drive circuit element 42 includes both the diode D and the resistor R, each of the diode D and the resistor R may be mounted on, for example, the second substrate surface 41 s of the second substrate 41.

[0266] [Modifications of the Cap] In each embodiment, the end of the cylindrical portion 51 that comes into contact with the base 21 may have a flange. The flange is formed around the entire circumference of the cylindrical portion 51, for example.

[0267] In each embodiment, the light-transmitting plate 54 may be omitted. In each embodiment, the cap 50 may be formed by separately forming the cylindrical portion 51 and the top plate portion 52. In this case, the cylindrical portion 51 and the top plate portion 52 are joined to each other by adhesive or welding.

[0268] [Modification of Semiconductor Light Emitting Unit] The inner surface defining the through hole 143 of the cap cover portion 140 of the heat sink 110 and the cap 50 of the semiconductor light emitting device 10 may be in partial contact in the circumferential direction of the cap 50 .

[0269] The through hole 143 of the cap cover part 140 may have an opening that does not cover the cap 50 in the circumferential direction of the cap 50. The diameter of the through hole 143 of the cap cover part 140 may be larger than the outer diameter of the cap 50. In other words, the cap 50 may be inserted into the through hole 143. In this case, as shown in FIG. 37 , for example, a heat dissipation member 160 is interposed between the cylindrical part 51 of the cap 50 and the inner surface that forms the through hole 143. The heat dissipation member 160 may be, for example, a known thermally conductive compound or a thermally conductive sheet (heat dissipation sheet).

[0270] 38 is a view seen from the first cover surface 141 of the cap cover part 140 with the opening cover member 150 (see FIG. 37) omitted. As shown in FIG. 37, the heat dissipation member 160 may be interposed between the cylindrical part 51 of the cap 50 and the inner surface that forms the through hole 143 over the entire circumference of the cylindrical part 51 of the cap 50.

[0271] This configuration allows heat from the semiconductor light emitting device 10 to be easily transferred from the cap 50 to the cap cover part 140 via the heat dissipation member 160. This makes it possible to prevent the temperature of the semiconductor light emitting device 10 from becoming excessively high.

[0272] In addition, the heat dissipation member 160 is interposed between the cylindrical portion 51 of the cap 50 and the inner surface forming the through hole 143 around the entire circumference of the cylindrical portion 51 of the cap 50, thereby making it easier for heat from the semiconductor light-emitting device 10 to be transmitted from the cap 50 to the cap cover portion 140 via the heat dissipation member 160.

[0273] The heat dissipation member 160 may be provided partially in the circumferential direction of the cylindrical portion 51 of the cap 50. The heat dissipation member 160 may be provided partially in the height direction (z direction) of the cylindrical portion 51 of the cap 50.

[0274] The base 21 of the semiconductor light emitting device 10 and the cap cover portion 140 may be spaced apart from each other. The opening cover member 150 may be omitted from the semiconductor light emitting unit 100.

[0275] The circuit board 120 may be disposed so as to be in contact with the heat dissipation base 130. In this case, the heat dissipation base 130 may have, for example, an accommodating recess that accommodates the terminal portions 29A to 29D of the plurality of lead pins 23A to 23D of the semiconductor light emitting device 10. The accommodating recess allows the terminal portions 29A to 29D to be spaced apart from the heat dissipation base 130.

[0276] In the first embodiment, the semiconductor light emitting unit 100 may include the semiconductor light emitting device 10X shown in Fig. 16. Because the configurations of the cap 50 and the base 21 are the same as those of the semiconductor light emitting unit 100 of the first embodiment, the effects (1-14) to (1-19) of the first embodiment can also be obtained with this configuration. In this way, the semiconductor light emitting unit 100 does not need to be configured so that the semiconductor light emitting element 32 is mounted on a substrate (first substrate 31) separate from the second substrate 41.

[0277] The semiconductor light emitting unit 100 may include any one of the semiconductor light emitting devices 10 according to the second to sixth embodiments. The semiconductor light emitting device used in the semiconductor light emitting unit 100 may be a semiconductor light emitting device that does not include the drive unit 40. In this case, the semiconductor light emitting device may have a configuration in which the semiconductor light emitting element 32 is mounted on the heat sink 22. In other words, the semiconductor light emitting device does not need to include the first substrate 31.

[0278] The term "on" used in this disclosure includes the meanings of "on" and "above" unless the context clearly indicates otherwise. Therefore, the expression "A is formed on B" is intended to mean that, although in each of the above embodiments, A may be in contact with B and disposed directly on B, as a modified example, A may be disposed above B without contacting B. In other words, the term "on" does not exclude a structure in which another member is formed between A and B.

[0279] The z-direction used in this disclosure does not necessarily have to be the vertical direction, nor does it have to completely coincide with the vertical direction. Therefore, various structures according to this disclosure are not limited to the "up" and "down" of the z-direction described herein being "up" and "down" of the vertical direction. For example, the x-direction may be the vertical direction, or the y-direction may be the vertical direction.

[0280] <Supplementary Notes> The technical ideas that can be understood from the above-described embodiments and modified examples are described below. Note that, for the purpose of aiding understanding and not intending to limit the scope of the invention, the corresponding reference numerals in the embodiments are shown in parentheses for the configurations described in the Supplementary Notes. The reference numerals are shown as examples to aid understanding, and the components described with the reference numerals should not be limited to the components indicated by the reference numerals.

[0281] [Appendix A1] A semiconductor light emitting device (10) comprising: a base (21); a conductive heat sink (22) erected on the base (21); a first substrate (31) and a second substrate (41) attached to the heat sink (22) so as to be spaced apart from each other; a semiconductor light emitting element (32) mounted on the first substrate (31); and a drive circuit element (42) mounted on the second substrate (41) for driving the semiconductor light emitting element (32).

[0282] [Appendix A2] The semiconductor light-emitting device according to Appendix A1, wherein the first substrate (31) includes a first base material (31A), the second substrate (41) includes a second base material (41A), and the thermal conductivity of the first base material (31A) is higher than the thermal conductivity of the second base material (41A).

[0283] [Appendix A3] The semiconductor light-emitting device according to Appendix A1 or A2, wherein the first substrate (31) includes a first base material (31A), and the difference between the linear expansion coefficient of the first base material (31A) and the linear expansion coefficient of the semiconductor light-emitting element (32) is smaller than the difference between the linear expansion coefficient of the heat sink (22) and the linear expansion coefficient of the semiconductor light-emitting element (32).

[0284] [Appendix A4] The semiconductor light-emitting device according to any one of Appendices A1 to A3, wherein the first substrate (31) includes a first base material (31A), and the first base material (31A) is formed from any one of aluminum nitride, alumina, a copper-tungsten alloy (CuW), copper-aluminum nitride-copper (Cu-AlN-Cu), a copper-diamond alloy, and a silver-diamond alloy.

[0285] [Appendix A5] The semiconductor light emitting device according to any one of Appendices A1 to A4, wherein the drive circuit element (42) includes a switching element (43) and a capacitor (44).

[0286] [Appendix A6] The heat sink (22) includes a second mounting surface (24B) to which the second substrate (41) is attached, and a first mounting surface (24A) formed closer to the tip of the heat sink (22) than the second mounting surface (24B) and to which the first substrate (31) is attached, and the first mounting surface (24A) protrudes from the second mounting surface (24B) in a thickness direction (y direction) perpendicular to the erection direction (z direction) of the heat sink. A semiconductor light emitting device described in any one of Appendices A1 to A5.

[0287] [Appendix A7] The semiconductor light-emitting device described in Appendix A6, wherein the drive circuit element (42) includes a capacitor (44) having a first electrode (44A) and a second electrode (44B), the first electrode (44A) of the capacitor (44) is mounted on the first mounting surface (24A), and the second electrode (44B) of the capacitor (44) is mounted on the second substrate (41).

[0288] [Appendix A8] The semiconductor light-emitting device according to any one of Appendices A1 to A7, wherein the semiconductor light-emitting element (32) includes an anode electrode (36) and a cathode electrode (37), and the first substrate (31) includes a through-hole (34) that electrically connects the cathode electrode (36) and the heat sink (22).

[0289] [Appendix A9] The semiconductor light-emitting device described in Appendix A6 or A7, wherein the second substrate (41) includes a substrate surface (41s) on which the drive circuit element (42) is mounted, and the first mounting surface (24A) and the substrate surface (41s) are at the same position in the thickness direction (y direction) of the heat sink.

[0290] [Appendix A10] The semiconductor light emitting device according to any one of Appendices A1 to A5, wherein the heat sink (22) includes a mounting surface (24) to which both the first substrate (31) and the second substrate (41) are attached.

[0291] [Appendix A11] The semiconductor light-emitting device described in Appendix A10, wherein a recess (49) recessed from the end of the second substrate (41) is formed at the end, and the first substrate (31) is arranged so that at least a portion of the first substrate (31) extends into a region (RG) formed by the recess (49) while being spaced apart from the second substrate (41).

[0292] [Appendix A12] The semiconductor light-emitting device according to Appendix A10 or A11, wherein the drive circuit element (42) includes a capacitor (44) having a first electrode (44A) and a second electrode (44B), both of the first electrode (44A) and the second electrode (44B) of the capacitor (44) are mounted on the second substrate (31), and the second substrate (31) includes a through-hole (63) that electrically connects the first electrode (44A) of the capacitor (44) to the heat sink (22).

[0293] [Appendix A13] The semiconductor light-emitting device described in Appendix A12, wherein the second substrate (41) includes a pad (68) electrically connected to the heat sink (22), and the first electrode (44A) of the capacitor (44) is electrically connected to the semiconductor light-emitting element (32) via the through hole (63), the pad (68), and the first substrate (31).

[0294] [Appendix A14] The semiconductor light-emitting device according to any one of Appendices A1 to A13, wherein the drive circuit element (42) includes a switching element (43), and a capacitor (44) having a first electrode (44A) and a second electrode (44B), wherein the semiconductor light-emitting element (32) and the switching element (43) are arranged spaced apart from each other in the erection direction (z direction) of the heat sink (22), and a connection wiring (72) for electrically connecting the second substrate (41) to the heat sink (22) is provided in a portion of the second substrate (41) between the semiconductor light-emitting element (32) and the switching element (43) in the erection direction (z direction), and the first electrode (44A) of the capacitor (44) is mounted on the connection wiring (72).

[0295] [Appendix A15] The semiconductor light-emitting device according to Appendix A14, wherein the connection wiring (72) and the heat sink (22) are connected by a wire (W5).

[0296] [Appendix A16] The semiconductor light emitting device according to any one of Appendices A1 to A15, wherein the semiconductor light emitting element (32) has a plurality of light emitting portions (32A).

[0297] [Appendix A17] The semiconductor light-emitting device according to any one of Appendices A1 to A16, further comprising a cap (50) attached to the base (21) and covering the heat sink (22), the first substrate (31), the second substrate (41), the semiconductor light-emitting element (32), and the drive circuit element (42), wherein the cap (50) has an opening (53) through which light from the semiconductor light-emitting element (32) can exit.

[0298] [Appendix A18] A semiconductor light emitting device (10) comprising: a base (21); an electrically conductive heat sink (22) erected on the base (21); a substrate (41) attached to the heat sink (22); a semiconductor light emitting element (32) attached directly to the heat sink (22) at a position different from the substrate; and a drive circuit element (42) at least partially mounted on the substrate (41) and driving the semiconductor light emitting element (32).

[0299] [Appendix A19] The semiconductor light emitting device according to Appendix A18, wherein the semiconductor light emitting element (32) is bonded to the heat sink (22) by a conductive bonding material.

[0300] [Appendix A20] The semiconductor light-emitting device according to appendix A18 or A19, wherein the drive circuit element (42) includes a switching element (43) and a capacitor (44).

[0301] [Appendix A21] The heat sink (22) includes a second mounting surface (24B) to which the substrate (41) is attached, and a first mounting surface (24A) formed closer to the tip of the heat sink (22) than the second mounting surface (24B) and to which the semiconductor light-emitting element is directly attached, and the first mounting surface (24A) protrudes from the second mounting surface (24B) in a thickness direction (y direction) perpendicular to the erection direction (z direction) of the heat sink. The semiconductor light-emitting device described in any one of Appendices A18 to A20.

[0302] [Appendix A22] The semiconductor light-emitting device described in Appendix A21, wherein the drive circuit element (42) includes a capacitor (44) having a first electrode (44A) and a second electrode (44B), the first electrode (44A) of the capacitor (44) is mounted on the first mounting surface (24A), and the second electrode (44B) of the capacitor (44) is mounted on the substrate (41).

[0303] [Appendix A23] The semiconductor light-emitting device described in Appendix A21 or A22, wherein the substrate (41) includes a substrate surface (41s) on which the drive circuit element (42) is mounted, and the first mounting surface (24A) and the substrate surface (41s) are at the same position in the thickness direction (y direction) of the heat sink.

[0304] [Appendix A24] The semiconductor light emitting device according to any one of Appendices A18 to A20, wherein the heat sink (22) includes a mounting surface (24) to which both the semiconductor light emitting element (32) and the substrate (41) are attached.

[0305] [Appendix A25] The semiconductor light-emitting device according to Appendix A24, wherein a recess (49) recessed from the end of the substrate (41) is formed at the end, and the semiconductor light-emitting element (32) is arranged so that at least a portion of the semiconductor light-emitting element is inserted into a region (RG) formed by the recess (49) while being spaced apart from the substrate (41).

[0306] [Appendix A26] The semiconductor light-emitting device described in Appendix A24 or A25, wherein the drive circuit element (42) includes a capacitor (44) having a first electrode (44A) and a second electrode (44B), both of the first electrode (44A) and the second electrode (44B) of the capacitor (44) are mounted on the substrate (31), and the substrate (31) includes a through-hole (63) that electrically connects the first electrode (44A) of the capacitor (44) to the heat sink (22).

[0307] [Appendix A27] The semiconductor light-emitting device described in Appendix A26, wherein the substrate (41) includes a pad (68) electrically connected to the heat sink (22), and the first electrode (44A) of the capacitor (44) is electrically connected to the semiconductor light-emitting element (32) via the through hole (63), the pad (68), and the heat sink (22).

[0308] [Appendix A28] The semiconductor light-emitting device according to any one of Appendices A18 to A23, wherein the drive circuit element (42) includes a switching element (43), and a capacitor (44) having a first electrode (44A) and a second electrode (44B), wherein the semiconductor light-emitting element (32) and the switching element (43) are arranged spaced apart from each other in the erection direction (z direction) of the heat sink (22), and a connection wiring (72) for electrically connecting the substrate (41) to the heat sink (22) is provided in a portion of the substrate (41) between the semiconductor light-emitting element (32) and the switching element (43) in the erection direction (z direction), and the first electrode (44A) of the capacitor (44) is mounted on the connection wiring (72).

[0309] [Appendix A29] The semiconductor light-emitting device according to Appendix A28, wherein the connection wiring (72) and the heat sink (22) are connected by a wire (W5).

[0310] [Appendix A30] The semiconductor light emitting device according to any one of Appendices A18 to A29, wherein the semiconductor light emitting element (32) has a plurality of light emitting portions (32A).

[0311] [Appendix A31] The semiconductor light-emitting device according to any one of Appendices A18 to A30, further comprising a cap (50) attached to the base (21) and covering the heat sink (22), the substrate (41), the semiconductor light-emitting element (32), and the drive circuit element (42), wherein the cap (50) has an opening (53) through which light from the semiconductor light-emitting element (32) can exit.

[0312] [Appendix A32] The semiconductor light emitting device according to Appendix A8, wherein the first substrate (31) includes a heat dissipation material (35) provided in the through hole (34).

[0313] [Appendix A33] A semiconductor light emitting unit (100) comprising: the semiconductor light emitting device (10) according to any one of Appendices A1 to A32; and a heat sink (110) to which the semiconductor light emitting device (10) is attached.

[0314] [Appendix A34] The semiconductor light-emitting device (10) has an opening (53) that opens in one direction and a side surface that faces a direction intersecting the one direction, and is provided with a cap (50) that covers the semiconductor light-emitting element (32) and the drive circuit element (42). The semiconductor light-emitting unit described in Appendix A33.

[0315] [Appendix A35] The semiconductor light-emitting unit described in Appendix A34, wherein the heat sink (110) includes: a plate-shaped heat dissipation base (130); and a cap cover portion (140) that stands upright from the heat dissipation base (130) and is thermally connected to a side surface of the cap (50) with the opening (53) facing in a direction (z direction) intersecting the thickness direction (y direction) of the heat dissipation base (130).

[0316] [Appendix A36] The semiconductor light emitting unit according to Appendix A35, wherein the heat dissipation base (130) includes a base surface (131) on which the cap cover portion (140) is erected, and the unit is provided with a circuit board (120) arranged parallel to the base surface (131) of the heat dissipation base (130), and the unit has a plurality of lead pins (23A to 23D) protruding from the plate-shaped base (21) toward the opposite side to the cap (50) in the thickness direction (z direction) of the base (21), and the semiconductor light emitting device (10) is attached to the cap cover portion (140) so that the thickness direction (z direction) of the base (21) intersects with the thickness direction (y direction) of the heat dissipation base (130), and the semiconductor light emitting device (10) is mounted on the circuit board (120) with each of the plurality of lead pins (23A to 23D) bent.

[0317] [Appendix A37] The semiconductor light-emitting unit described in Appendix A35 or A36, wherein the cap cover portion (140) is configured to be connected to the side of the cap (50) in a heat-transferable manner, and the cap cover portion (140) includes a through hole (143) into which the cap (50) is press-fitted.

[0318] [Appendix A38] The semiconductor light-emitting unit described in Appendix A35 or A36, wherein the cap cover portion (140) includes a through hole (143) into which the cap (50) is inserted, and the cap cover portion (140) is configured to be thermally connected to the side of the cap (50), and a heat dissipation member (160) is interposed between the inner surface constituting the through hole (143) and the side of the cap.

[0319] [Appendix A39] The semiconductor light-emitting unit according to Appendix A37 or A38, wherein the inner surface of the through hole (143) is connected to the side surface of the cap (50) over the entire periphery in a manner that allows heat transfer.

[0320] [Appendix A40] The semiconductor light emitting unit according to any one of Appendices A37 to A39, further comprising an opening cover member (150) attached to the cap cover portion (140) and provided to cover the through hole (143).

[0321] [Appendix A41] The semiconductor light-emitting unit according to any one of Appendices A35 to A40, wherein the cap (50) has a top plate portion (52) having the opening (53) and a tubular portion (51) having the top plate portion (52) at one end thereof, and the side surface is the outer peripheral surface of the tubular portion (51).

[0322] [Appendix A42] The semiconductor light emitting unit according to any one of Appendices A35 to A41, wherein the cap cover portion (140) is in contact with the base (21).

[0323] [Appendix A43] The semiconductor light emitting unit according to any one of Appendices A35 to A42, wherein the cap cover portion (140) has a thickness (TCC) greater than a height dimension (HCP) of the cap (50).

[0324] [Appendix A44] The semiconductor light-emitting unit described in Appendix A36, wherein the heat dissipation base (130) includes a base back surface (132) facing opposite the base front surface (131), and the circuit board (120) is arranged spaced apart from the base front surface (131) of the heat dissipation base (130) on the opposite side of the base back surface (132) in the thickness direction (y direction) of the heat dissipation base (130).

[0325] [Appendix A45] The semiconductor light emitting unit described in Appendix A36 or A44, wherein the circuit board (120) is arranged in a position adjacent to the cap cover portion (140), and the plurality of lead pins (23A to 23D) are mounted on an end of the circuit board (120) adjacent to the cap cover portion (140).

[0326] [Appendix B1] A semiconductor light emitting unit (100) comprising: a semiconductor light emitting device (10); and a heat sink (110) to which the semiconductor light emitting device (10) is attached, wherein the semiconductor light emitting device (10) comprises: a semiconductor light emitting element (32); and a cap (50) that has an opening (53) that opens in one direction and a side surface facing a direction intersecting the one direction and covers the semiconductor light emitting element (32), and the heat sink (110) includes: a plate-shaped heat dissipation base (130); and a cap cover portion (140) that stands from the heat dissipation base (130) and is connected to a side surface of the cap (50) so as to be capable of conducting heat, with the opening (53) facing a direction (z direction) intersecting a thickness direction (y direction) of the heat dissipation base (130).

[0327] [Appendix B2] The semiconductor light emitting unit according to Appendix B1, wherein the heat dissipation base (130) includes a base surface (131) on which the cap cover portion (140) is erected, and the semiconductor light emitting device (10) comprises a circuit board (120) arranged parallel to the base surface (131) of the heat dissipation base (130), and the semiconductor light emitting device (10) has a plate-shaped base (21) to which the cap (50) is attached, and a plurality of lead pins (23A to 23D) protruding from the base (21) toward the opposite side to the cap (50) in the thickness direction (z direction) of the base (21), and the semiconductor light emitting device (10) is attached to the cap cover portion (140) such that the thickness direction (z direction) of the base (21) intersects with the thickness direction (y direction) of the heat dissipation base (130), and the semiconductor light emitting device (10) is mounted on the circuit board (120) with each of the plurality of lead pins (23A to 23D) bent.

[0328] [Appendix B3] The semiconductor light-emitting unit described in Appendix B1 or B2, wherein the cap cover portion (140) is configured to be connected to the side of the cap (50) in a heat-transferable manner, and the cap cover portion (140) includes a through hole (143) into which the cap (50) is press-fitted.

[0329] [Appendix B4] The semiconductor light-emitting unit described in Appendix B1 or B2, wherein the cap cover portion (140) includes a through hole (143) into which the cap (50) is inserted, and the cap cover portion (140) is configured to be thermally connected to the side of the cap (50), and a heat dissipation member (160) is interposed between the inner surface constituting the through hole (143) and the side of the cap.

[0330] [Appendix B5] The semiconductor light-emitting unit according to Appendix B3 or B4, wherein the inner surface of the through-hole (143) is connected to the side surface of the cap (50) over the entire periphery in a manner that allows heat transfer.

[0331] [Appendix B6] The semiconductor light-emitting unit according to any one of Appendices B3 to B5, wherein the cap (50) has a top plate portion (52) having the opening (53) and a tubular portion (51) having the top plate portion (52) at one end, and the side surface is the outer peripheral surface of the tubular portion (51).

[0332] [Appendix B7] The semiconductor light emitting unit according to Appendix B2, wherein the cap cover portion (140) is in contact with the base (21).

[0333] [Appendix B8] The semiconductor light emitting unit according to any one of Appendices B1 to B7, wherein the cap cover portion (140) has a thickness (TCC) greater than a height dimension (HCP) of the cap (50).

[0334] [Appendix B9] The semiconductor light emitting unit according to any one of Appendices B3 to B6, further comprising an opening cover member (150) attached to the cap cover portion (140) and provided to cover the through hole (143).

[0335] [Appendix B10] The semiconductor light-emitting unit described in Appendix B2, wherein the heat dissipation base (130) includes a base back surface (132) facing the opposite side to the base front surface (131), and the circuit board (120) is arranged spaced apart from the base front surface (131) of the heat dissipation base (130) on the opposite side to the base back surface (132) in the thickness direction (y direction) of the heat dissipation base (130).

[0336] [Appendix B11] The semiconductor light emitting unit according to Appendix B2 or B10, wherein the circuit board (120) is arranged in a position adjacent to the cap cover portion (140), and the plurality of lead pins (23A to 23D) are mounted on an end of the circuit board (120) adjacent to the cap cover portion (140).

[0337] [Appendix B12] The semiconductor light emitting device (10) includes a drive circuit element (42) that drives the semiconductor light emitting element (32), and the cap (50) covers the drive circuit element (42). The semiconductor light emitting unit according to any one of Appendices B1 to B11.

[0338] [Appendix B13] The semiconductor light-emitting unit according to Appendix B12, wherein the drive circuit element (42) includes a switching element (43) and a capacitor (44).

[0339] The above description is merely illustrative. Those skilled in the art will recognize that many more possible combinations and permutations are possible other than the components and methods (manufacturing processes) listed for the purpose of illustrating the technology of the present disclosure. The present disclosure is intended to embrace all alternatives, modifications, and variations that fall within the scope of the present disclosure, including the claims.

[0340] REFERENCE SIGNS LIST 10...Semiconductor light emitting device 10X...Comparative example semiconductor light emitting device 20...Stem 21...Base 21s...Base surface 21r...Base back surface 21A-21C...Through hole 22...Heat sink 22a...Tip surface 23A-23D...Lead pin 24...Mounting surface 24A...First mounting surface 24B...Second mounting surface 25...Step portion 26...Protrusion 27...Insulating material 28A-28C...Connection portion 29A-29D...Terminal portion 29DA...Connection portion 30...Light emitting unit 31...First substrate 31A...First base material 31s...First substrate surface 31r...First substrate back surface 32...Semiconductor light emitting element 32A...Light emitting portion 32a...Light emitting surface 32s...Element surface 32r...Element back surface 33s...Front surface wiring 33r...Back surface wiring 34...Through hole 35...heat dissipation material 36...anode electrode 37...cathode electrode 40...drive unit 41...second substrate 41A...second base material 41s...surface of second substrate 41r...rear surface of second substrate 41a, 41b...side surfaces of second substrate 42...drive circuit element 43...switching element 43s...surface of switching element 43r...rear surface of switching element 43S...source electrode 43D...drain electrode 43G...gate electrode 44...capacitor 44A...first electrode 44B...second electrode 45s...surface side wiring 46s...surface side resist layer 46r...rear side resist layer 46a...opening for switching element 46b...opening for capacitor 46c...opening for wire 47...through hole 48...heat dissipation material 49...recess 50...cap 51...tubular portion 52...top plate portion 53...opening 54...translucent plate 61...First surface side wiring 62...Second surface side wiring 63...First through hole 64...Second through hole 65...First heat dissipation material 66...Second heat dissipation material 67...Front surface side resist layer 67a...Opening for switching element 67b...Opening for first capacitor 67c...Opening for second capacitor 67d...Opening for wire 68...Back surface side wiring 69A...First back surface side resist layer 69B...Second back surface side resist layer 69BA...Opening 71...Front surface side wiring 72...Connecting wiring 73...Through hole 74...Heat dissipation material 75...Front surface side resist layer 75a...Opening for switching element 75b...Opening for first capacitor75c...Opening for second capacitor 75d...Opening for first wire 75e...Opening for second wire 76...First back surface resist layer 77...Second back surface resist layer 100...Semiconductor light emitting unit 100X...Semiconductor light emitting unit of comparative example 110...Heat sink 120...Circuit board 130...Heat sink base 131...Base surface 132...Base back surface 133-136...Base side surface 140...Cap cover portion 141...First cover surface 142...Second cover surface 143...Through hole 150...Opening cover member 151...Bottom 152...Opening 160...Heat sink member LS...Laser system D...Diode R...Resistance element DV...Drive power supply PM...Driver circuit RG...Area W1-W5...Wire DB...Distance in the y direction between the second mounting surface and the second substrate surface of the second substrate DH...distance between the second mounting surface and the first mounting surface in the y direction G1...distance between the first board and the tip surface of the heat sink G2...distance between the first board and the bottom surface of the recess in the second board HB...height of the second board from the mounting surface HC1...height of the capacitor from the first mounting surface HC2...height of the capacitor from the surface of the second board HCP...height dimension of the cap HL1...height of the semiconductor light emitting element from the first mounting surface HL2...height of the semiconductor light emitting element from the mounting surface HR...depth of the recess HS...height of the switching element from the surface of the second board LR...size of the recess in the x direction LSX...size of the switching element in the x direction LZ...size of the first board in the z direction TB1...thickness of the first board TB2...thickness of the second board TCC...thickness of the cap cover portion TL...thickness of the semiconductor light emitting element TS...thickness of the switching element

Claims

1. A semiconductor light emitting device; a heat sink to which the semiconductor light emitting device is attached; Equipped with The semiconductor light emitting device comprises: A semiconductor light emitting element; a cap having an opening that opens in one direction and a side surface that faces a direction intersecting the one direction, the cap covering the semiconductor light emitting element; The heat sink is A plate-shaped heat dissipation base; a cap cover part that stands from the heat dissipation base and is connected to a side surface of the cap in a heat transferable manner with the opening facing a direction intersecting a thickness direction of the heat dissipation base; Includes Semiconductor light emitting unit.

2. the heat dissipation base includes a base surface on which the cap cover is provided, a circuit board disposed parallel to the base surface of the heat dissipation base; The semiconductor light emitting device is A plate-shaped base to which the cap is attached; a plurality of lead pins protruding from the base toward an opposite side to the cap in a thickness direction of the base, The semiconductor light emitting device is attached to the cap cover part so that a thickness direction of the base intersects with a thickness direction of the heat dissipation base part, and is mounted on the circuit board with each of the plurality of lead pins bent. The semiconductor light emitting unit according to claim 1 .

3. The cap cover portion is configured to be connected to a side surface of the cap in a heat-transferable manner, and the cap cover portion includes a through hole into which the cap is press-fitted. The semiconductor light emitting unit according to claim 1 .

4. the cap cover portion includes a through hole into which the cap is inserted, The cap cover portion is configured to be connected to a side surface of the cap in a manner capable of transferring heat therebetween, and a heat dissipation member is interposed between an inner surface constituting the through hole and the side surface of the cap. The semiconductor light emitting unit according to claim 1 .

5. The inner surface constituting the through hole is connected to the side surface of the cap over the entire circumference so as to be capable of thermal transfer. The semiconductor light-emitting unit according to claim 3 or 4.

6. The cap is A top plate portion having the opening and a tube portion having the top plate portion at one end thereof, The side surface is an outer circumferential surface of the cylindrical portion. The semiconductor light emitting unit according to claim 1 .

7. The cap cover portion is in contact with the base. The semiconductor light-emitting unit according to claim 2 .

8. The cap cover portion has a thickness greater than a height dimension of the cap. The semiconductor light emitting unit according to claim 1 .

9. An opening cover member is attached to the cap cover portion and provided to cover the through hole. The semiconductor light-emitting unit according to claim 3 or 4.

10. The heat dissipation base includes a back surface of the base facing away from the front surface of the base, The circuit board is disposed on the opposite side of the base back surface of the heat dissipation base in the thickness direction of the heat dissipation base, the opposite side of the base back surface of the heat dissipation base. The semiconductor light-emitting unit according to claim 2 .

11. the circuit board is disposed adjacent to the cap cover portion, The plurality of lead pins are mounted on an end of the circuit board adjacent to the cap cover portion. The semiconductor light-emitting unit according to claim 2 .

12. the semiconductor light emitting device includes a drive circuit element for driving the semiconductor light emitting element, The cap covers the driving circuit element. The semiconductor light emitting unit according to claim 1 .

13. The drive circuit element includes a switching element and a capacitor. The semiconductor light emitting unit according to claim 12.