Semiconductor laser light emitting device

Abstract

A semiconductor laser light emitting device (1) comprises a mounting substrate (10), which is an example of a mounting base having a step (11), a submount (20) arranged above the bottom surface of the step (11), and a semiconductor laser (30) arranged at the submount (20), wherein a first side surface, which is one of the inner side surfaces of the step (11), and a front surface (20a), which is the surface of the submount (20) on the light emitting side of the semiconductor laser (30), are in thermal contact with each other.

Description

Semiconductor laser light emitting device

[0001] The present disclosure relates to a semiconductor laser light emitting device including a semiconductor laser.

[0002] Semiconductor laser light-emitting devices are used as light sources for products in various fields, such as projectors, vehicle headlamps, laser processing machines, etc. This type of semiconductor laser light-emitting device includes, for example, a substrate serving as a mounting base, a submount mounted on the substrate, and a semiconductor laser mounted on the submount (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2015-228401

[0004] Up until now, semiconductor laser light emitting devices have been required to have higher output power, but in recent years, there has been a demand for semiconductor laser light emitting devices to have even higher output power.

[0005] In order to increase the output of a semiconductor laser light emitting device, it is conceivable to increase the current flowing through the semiconductor laser to increase the current capacity of the semiconductor laser, or to use a plurality of semiconductor lasers in a multi-chip configuration.

[0006] However, if the current flowing through the semiconductor laser is increased or multiple semiconductor lasers are used, the amount of heat generated by the semiconductor laser increases, causing the temperature of the semiconductor laser to rise, resulting in a decrease in the output of the laser light emitted from the semiconductor laser and a decrease in the reliability of the semiconductor laser.

[0007] Therefore, when increasing the output of a semiconductor laser light-emitting device, it is important to efficiently conduct the heat generated by the semiconductor laser to the mounting base.In addition, in a semiconductor laser light-emitting device, it is also important to mount the semiconductor laser on the mounting base with high accuracy.

[0008] The present disclosure has been made to solve such problems, and aims to provide a semiconductor laser light-emitting device that can efficiently conduct heat generated by a semiconductor laser to a mounting base via a submount and that can mount the semiconductor laser on the mounting base with high precision.

[0009] In order to achieve the above-mentioned object, one aspect of the semiconductor laser light-emitting device according to the present disclosure comprises a mounting base having a step, a submount arranged above the bottom surface of the step, and a semiconductor laser arranged on the submount, wherein a first side surface, which is one of the inner surfaces of the step, and a front surface, which is the light-emitting side surface of the semiconductor laser on the submount, are in thermal contact with each other.

[0010] According to the present disclosure, heat generated by the semiconductor laser can be efficiently conducted to the mounting base via the submount, and the semiconductor laser can be mounted on the mounting base with high precision.

[0011] FIG. 1A is a perspective view of a semiconductor laser light emitting device according to embodiment 1. FIG. 1B is a top view of the semiconductor laser light emitting device according to embodiment 1. FIG. 2A is a cross-sectional view showing a portion of the semiconductor laser light emitting device according to embodiment 1. FIG. 2B is a top view showing a portion of the semiconductor laser light emitting device according to embodiment 1. FIG. 2C is a perspective view showing a portion of the semiconductor laser light emitting device according to embodiment 1. FIG. 3 is a cross-sectional view showing a configuration and heat dissipation paths of a semiconductor laser light emitting device of comparative example 1. FIG. 4 is a cross-sectional view showing a configuration and heat dissipation paths of a semiconductor laser light emitting device according to embodiment 1. FIG. 5A is a cross-sectional view showing a portion of a semiconductor laser light emitting device according to modification 1 of embodiment 1. FIG. 5B is a top view showing a portion of a semiconductor laser light emitting device according to modification 1 of embodiment 1. FIG. 5C is a perspective view showing a portion of a semiconductor laser light emitting device according to modification 1 of embodiment 1. FIG. 6A is a cross-sectional view showing a portion of a semiconductor laser light emitting device according to modification 2 of embodiment 1. FIG. 6B is a top view showing a portion of a semiconductor laser light emitting device according to modification 2 of embodiment 1. FIG. 6C is a perspective view showing a portion of a semiconductor laser light emitting device according to Modification 2 of Embodiment 1. FIG. 7 is a cross-sectional view showing a portion of a semiconductor laser light emitting device according to Modification 3 of Embodiment 1. FIG. 8 is a cross-sectional view showing a portion of a semiconductor laser light emitting device according to Modification 4 of Embodiment 1. FIG. 9A is a cross-sectional view showing a portion of a semiconductor laser light emitting device according to Embodiment 2. FIG. 9B is a top view showing a portion of a semiconductor laser light emitting device according to Embodiment 2. FIG. 9C is a perspective view showing a portion of a semiconductor laser light emitting device according to Embodiment 2. FIG. 10A is a cross-sectional view showing a portion of a semiconductor laser light emitting device according to a modification of Embodiment 2. FIG. 10B is a top view showing a portion of a semiconductor laser light emitting device according to a modification of Embodiment 2. FIG. 10C is a perspective view showing a portion of a semiconductor laser light emitting device according to a modification of Embodiment 2. FIG. 11A is a cross-sectional view showing a portion of a semiconductor laser light emitting device according to Embodiment 3. FIG. 11B is a top view showing a portion of a semiconductor laser light emitting device according to Embodiment 3. FIG. 11C is a perspective view showing a portion of a semiconductor laser light emitting device according to Embodiment 3. FIG. 12 is a cross-sectional view showing a configuration of a semiconductor laser light emitting device of Comparative Example 2.FIG. 13 is a cross-sectional view showing the configuration of a semiconductor laser light emitting device according to embodiment 3. FIG. 14 is a top view showing the configuration of a semiconductor laser light emitting device according to modification 1 of embodiment 3. FIG. 15 is a top view showing the configuration of a semiconductor laser light emitting device according to modification 2 of embodiment 3. FIG. 16A is a top view showing a portion of a semiconductor laser light emitting device according to embodiment 4. FIG. 16B is a perspective view showing a portion of a semiconductor laser light emitting device according to embodiment 4. FIG. 17A is a top view showing a portion of a semiconductor laser light emitting device according to modification 1 of embodiment 4. FIG. 17B is a perspective view showing a portion of a semiconductor laser light emitting device according to modification 1 of embodiment 4. FIG. 18A is a top view showing a portion of a semiconductor laser light emitting device according to modification 2 of embodiment 4. FIG. 18B is a perspective view showing a portion of a semiconductor laser light emitting device according to modification 2 of embodiment 4. FIG. 19 is an exploded perspective view of a semiconductor laser light emitting device according to another modification.

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, component placement and connection configurations, steps (processes), and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, components that are not described in the independent claims that represent the highest concept of the present disclosure will be described as optional components.

[0013] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, the scales and the like do not necessarily match in each figure. In each figure, the same reference numerals are used to denote substantially the same components, and redundant explanations will be omitted or simplified.

[0014] First Embodiment First, the overall configuration of a semiconductor laser light emitting device 1 according to the first embodiment will be described with reference to Figures 1A and 1B. Figure 1A is a perspective view of the semiconductor laser light emitting device 1 according to the first embodiment. Figure 1B is a top view of the semiconductor laser light emitting device 1. Note that Figures 1A and 1B show the semiconductor laser light emitting device 1 with the top cover removed.

[0015] As shown in FIGS. 1A and 1B, the semiconductor laser light emitting device 1 includes a mounting substrate 10 , a submount 20 disposed on the mounting substrate 10 , and a semiconductor laser 30 disposed on the submount 20 .

[0016] In this embodiment, the semiconductor laser light emitting device 1 further includes a frame 40, a light-transmitting member 50, and a top cover (not shown). In the semiconductor laser light emitting device 1, the mounting substrate 10, the frame 40, the light-transmitting member 50, and the top cover form a housing having an approximately rectangular parallelepiped outer shape. The submount 20 and the semiconductor laser 30 are housed within this housing. This housing is preferably a sealed space. In other words, the semiconductor laser 30 is preferably disposed in the sealed space.

[0017] The frame 40 is disposed on the mounting substrate 10 so as to surround the submount 20 and the semiconductor laser 30. Specifically, when the emission direction of the semiconductor laser 30 is set to be forward, the frame 40 is formed by side walls that surround the lateral and rearward portions of the submount 20 and the semiconductor laser 30, and is formed along the outer peripheral edge of the mounting substrate 10. In this embodiment, the side walls of the frame 40 are also provided on the front side of the submount 20 and the semiconductor laser 30. Although not shown, a plate-shaped top cover is disposed on the upper end of the frame 40 so as to cover the semiconductor laser 30. The frame 40 and the top cover are made of a metal material such as copper, for example, but are not limited to this.

[0018] An opening 41 is formed in the frame 40 in front of the semiconductor laser 30. A light-transmitting member 50 is arranged to close the opening 41 of the frame 40. Light emitted from the semiconductor laser 30 passes through the light-transmitting member 50 and is emitted to the outside of the semiconductor laser light emitting device 1. The light-transmitting member 50 is, for example, a transparent plate such as a glass plate made of borosilicate glass, but is not limited to this.

[0019] A pair of lead pins 61 and 62 are attached to the rear portion of the semiconductor laser 30 in the frame 40 as conductive electrode terminals for supplying power from the outside to the semiconductor laser 30. Specifically, the pair of lead pins 61 and 62 are inserted into through holes formed in the rear portion of the frame 40. If the frame 40 is made of a conductive material, the inner surface of the through hole of the frame 40 into which the pair of lead pins 61 and 62 are inserted is covered with an insulating member such as hermetic sealing glass.

[0020] The pair of lead pins 61 and 62 are electrically connected to a pair of electrodes of the semiconductor laser 30. Specifically, the lead pin 61 is connected to one electrode of the semiconductor laser 30 by a gold wire 71. The lead pin 62 is connected to the electrode 22 of the submount 20 to which the other electrode of the semiconductor laser 30 is joined by a gold wire 72. In this embodiment, the lead pin 61 is a cathode terminal, and the lead pin 62 is an anode terminal. As an example, the lead pins 61 and 62 are made of an Fe—Ni alloy. Note that, although a plurality of gold wires 71 and 72 are provided, the present invention is not limited thereto and each may have only one.

[0021] Next, the detailed structure of the semiconductor laser light emitting device 1 according to this embodiment will be described with reference to Figures 2A, 2B, and 2C. Figures 2A, 2B, and 2C are diagrams showing a portion of the semiconductor laser light emitting device 1 shown in Figures 1A and 1B, and are respectively a cross-sectional view, a top view, and a perspective view of the portion of the semiconductor laser light emitting device 1. Note that Figures 2B and 2C do not show the bonding member 80.

[0022] The mounting substrate 10 is an example of a mounting base for mounting the semiconductor laser 30 and the submount 20. Specifically, the mounting substrate 10 has the submount 20 mounted thereon, on which the semiconductor laser 30 is mounted.

[0023] 2A to 2C, the mounting substrate 10 is generally flat and has a first main surface 10a and a second main surface 10b facing away from the first main surface 10a, as shown in Fig. 2A. In this embodiment, the submount 20 is mounted on the first main surface 10a of the mounting substrate 10. The shape of the mounting substrate 10 in top view is, for example, rectangular, but is not limited to this.

[0024] The material of the mounting substrate 10 is, for example, a metal material, a ceramic material, a glass material, or a resin material. In order to efficiently conduct the heat generated by the semiconductor laser 30 to the mounting substrate 10 via the submount 20, the mounting substrate 10 is preferably made of a material with high thermal conductivity, such as a metal material. Metal materials with high thermal conductivity that are practical for the mounting substrate 10 include, for example, copper and aluminum. In this embodiment, the mounting substrate 10 is a copper substrate made of copper.

[0025] As shown in FIGS. 2A to 2C , the mounting substrate 10 has a step 11. That is, the mounting substrate 10 is an example of a mounting base having the step 11. In this embodiment, the mounting substrate 10 has a protrusion 12, which constitutes the step 11. Specifically, the step 11 is formed by providing the protrusion 12 on the first main surface 10a of the mounting substrate 10. Therefore, the upper surface of the step 11 is the upper surface 12a of the protrusion 12, the inner surface of the step 11, which is the rising surface of the step 11, is the side surface 12b of the protrusion 12, and the bottom surface of the step 11, which is the depressed surface of the step 11, is the first main surface 10a of the mounting substrate 10. Furthermore, the protrusion 12 is provided facing the submount 20, and the side surface 12b of the protrusion 12 (the inner surface of the step 11) is the surface that faces the front surface 20a of the submount 20.

[0026] In this embodiment, the protrusion 12 is a bar-shaped rectangular parallelepiped. That is, the protrusion 12 is a laid-down quadrangular prism with a rectangular cross-sectional shape. Therefore, the shape of the top surface 12a (top surface of the step 11) of the protrusion 12 and the side surface 12b (inner surface of the step 11) of the protrusion 12 are each rectangular. Furthermore, the top surface 12a (top surface of the step 11) of the protrusion 12 and the side surface 12b (inner surface of the step 11) of the protrusion 12 are perpendicular, and the side surface 12b (inner surface of the step 11) of the protrusion 12 and the first main surface 10a of the mounting substrate 10 (bottom surface of the step 11) are perpendicular. In this specification, "perpendicular" does not have to be strictly perpendicular, and includes a case where the deviation from perpendicular is 5 degrees or less.

[0027] Furthermore, the side surface 12b of the protrusion 12 (the inner surface of the step 11) and the front surface 20a of the submount 20 are parallel to each other. As shown in Fig. 2A, the cross-sectional shape of the protrusion 12 is rectangular, and when the thickness of the submount body 21 is 200 µm, the protrusion 12 has a step height of 160 µm and a step width of 160 µm, or a step height of 80 µm and a step width of 80 µm, but is not limited to this. In this specification, "parallel" does not have to mean strictly parallel, and includes cases where the deviation from parallelism is 5 degrees or less.

[0028] 2B and 2C , the protrusion 12 extends in the width direction of the semiconductor laser 30. Therefore, the longitudinal direction of the protrusion 12 is the width direction of the semiconductor laser 30. The length of the protrusion 12 is longer than the width of the submount 20. Specifically, when the submount 20 is viewed from the front, the protrusion 12 covers the entire width direction of the front surface 20a of the submount 20, and both ends of the protrusion 12 in the longitudinal direction are located outside both ends of the front surface 20a of the submount 20 in the width direction.

[0029] In the present embodiment, the step 11 is formed by providing a protrusion 12 on the mounting substrate 10, but this is not limiting. For example, the step 11 may be formed by providing a recess in the mounting substrate 10. In this case, the upper surface (top surface) of the step 11 becomes the first main surface 10a of the mounting substrate 10, the inner side surface of the step 11 becomes the inner side surface of the recess, and the bottom surface of the step 11 becomes the bottom surface of the recess. The submount 20 is mounted on the bottom surface of the recess, not on the first main surface 10a of the mounting substrate 10.

[0030] 2A to 2C, a submount 20 is disposed on the mounting substrate 10. Specifically, the submount 20 is disposed on the bottom surface of a step 11 of the mounting substrate 10. In the present embodiment, the bottom surface of the step 11 is the first main surface 10a of the mounting substrate 10, and therefore the submount 20 is disposed on the first main surface 10a of the mounting substrate 10. In other words, the first main surface 10a of the mounting substrate 10 is the mounting surface on which the submount 20 is mounted.

[0031] The submount 20 is a base that supports the semiconductor laser 30. The semiconductor laser 30 is mounted on the submount 20. That is, the semiconductor laser 30 is located on the submount 20. The submount 20 is also located on the mounting substrate 10. Therefore, the submount 20 is located between the mounting substrate 10 and the semiconductor laser 30. In this way, the submount 20 and the semiconductor laser 30 are stacked in this order on the mounting substrate 10.

[0032] The submount 20 includes a submount body 21 and an electrode 22. The submount 20 also functions as a heat sink for dissipating heat generated by the semiconductor laser 30. Therefore, the submount body 21 may be made of either a conductive or insulating material, but is preferably made of a material with high thermal conductivity. The thermal conductivity of the submount body 21 is preferably 150 W / (m·K) or higher. As an example, the submount body 21 is made of a ceramic such as aluminum nitride (AlN) or polycrystalline silicon carbide (SiC), a metal material such as copper, or a diamond such as a single crystal diamond or a polycrystalline diamond. In this embodiment, the submount body 21 is made of AlN. The shape of the submount body 21 is, for example, a rectangular plate-like cuboid, but is not limited thereto.

[0033] The submount 20 has a front surface 20a, which is the surface on the light-emitting side of the semiconductor laser 30, and a rear surface 20b, which is the surface opposite the light-emitting side of the semiconductor laser 30. The front surface 20a of the submount 20 is the front end surface of the submount body 21, and the rear surface 20b of the submount 20 is the rear end surface of the submount body 21. The front surface 20a of the submount 20 is the surface facing the step 11 formed on the mounting substrate 10. Specifically, the front surface 20a of the submount 20 faces the protrusion 12 provided on the mounting substrate 10. In this embodiment, since the submount body 21 is a rectangular plate, the front surface 20a and rear surface 20b of the submount 20 are rectangular in shape. Furthermore, the front surface 20a and rear surface 20b of the submount 20 are approximately parallel to each other.

[0034] An electrode 22 (submount electrode) is disposed on the upper surface of the submount body 21 (the surface facing the semiconductor laser 30). The electrode 22 is made of a conductive material such as a metal material. In this embodiment, the electrode 22 is a copper electrode made of copper. The electrode 22 may be made of a single conductive film or a plurality of conductive films.

[0035] 2A , the submount 20 has an upper surface 20c that faces the semiconductor laser 30 and a lower surface 20d that faces the mounting substrate 10. In this embodiment, the upper surface 20c of the submount 20 is the upper surface of the electrode 22, and the lower surface 20d of the submount 20 is the lower surface of the submount body 21. In the submount 20, the upper surface 20c and the lower surface 20d are approximately parallel to each other.

[0036] The mounting substrate 10 and the submount 20 are joined by a bonding member 80. That is, the bonding member 80 is inserted between the mounting substrate 10 and the submount 20. Specifically, the bonding member 80 is interposed between the first main surface 10a of the mounting substrate 10 and the lower surface 20d of the submount 20. In this embodiment, the bonding member 80 is also interposed between the side surface 12b of the protrusion 12, which is the inner surface of the step 11 of the mounting substrate 10, and the front surface 20a of the submount 20. The bonding member 80 is, for example, Au paste, but is not limited to this.

[0037] Although not shown, the semiconductor laser 30 and the submount 20 are also joined by a joining member. Specifically, the joining member is interposed between the semiconductor laser 30 and the upper surface 20c of the submount 20. The joining member that joins the semiconductor laser 30 and the submount 20 can be, for example, AnSn solder.

[0038] When joining the mounting substrate 10 and the submount 20, the semiconductor laser 30 is joined to the submount 20 with AuSn solder, and then, for example, Au paste is applied to the mounting substrate 10 as a joining member 80, and the submount 20 with the semiconductor laser 30 joined thereto is placed on the Au paste, thereby joining the submount 20 to the mounting substrate 10.

[0039] The semiconductor laser 30 is a semiconductor laser element (laser chip) that emits laser light. In this embodiment, the semiconductor laser 30 is a nitride-based semiconductor laser element made of a nitride-based semiconductor material. As an example, the semiconductor laser 30 is a GaN-based semiconductor laser element that emits blue laser light.

[0040] The semiconductor laser 30 has a front end face 30 a, which is an end face from which laser light is emitted, and a rear end face 30 b, which is an end face on the rear side opposite to the front end face 30 a. The semiconductor laser 30 also has an optical waveguide formed between the front end face 30 a and the rear end face 30 b.

[0041] The semiconductor laser 30 has an elongated shape with the cavity length direction as the longitudinal direction. As an example, the length of the semiconductor laser 30 in the cavity length direction is 1.2 mm, but is not limited to this.

[0042] The semiconductor laser 30 is mounted on the upper surface of the submount 20. Specifically, the semiconductor laser 30 is mounted on the electrode 22 of the submount 20. In this embodiment, the semiconductor laser 30 is mounted on the submount 20 by junction-down mounting. However, the mounting form of the semiconductor laser 30 is not limited to this, and the semiconductor laser 30 may also be mounted on the submount 20 by junction-up mounting.

[0043] The semiconductor laser 30 is mounted so that its front end face 30a protrudes from the front face 20a of the submount 20. In other words, the semiconductor laser 30 protrudes from the front face 20a of the submount 20, and the front end face 30a of the semiconductor laser 30 is located closer to the light emission side of the semiconductor laser 30 than the front face 20a of the submount 20. The protrusion amount of the semiconductor laser 30 (the distance from the front face 20a of the submount 20 to the front end face 30a of the semiconductor laser 30) is, for example, 5 μm to 20 μm, but is not limited to this. In this embodiment, the protrusion amount of the semiconductor laser 30 is 10 μm.

[0044] As described above, the semiconductor laser 30 protrudes from the front surface 20a of the submount 20, but does not protrude as far as the step 11 of the mounting substrate 10. In other words, the semiconductor laser 30 does not protrude as far as the protrusion 12 provided on the mounting substrate 10, and the front end portion of the semiconductor laser 30 does not overlap the protrusion 12 in top view. The front end surface 30a of the semiconductor laser 30 is located between the front surface 20a of the submount 20 and the side surface 12b of the protrusion 12. Note that the semiconductor laser 30 may protrude as far as the step 11 of the mounting substrate 10. In other words, the front end portion of the semiconductor laser 30 may overlap the protrusion 12 provided on the mounting substrate 10 in top view.

[0045] In the semiconductor laser light emitting device 1 according to this embodiment, the side surface 12b of the protrusion 12, which is the inner surface of the step 11 formed on the mounting substrate 10, is in thermal contact with the front surface 20a of the submount 20. In this case, it is preferable that the side surface 12b of the protrusion 12, which is the inner surface of the step 11, and the front surface 20a of the submount 20 are physically close to or in contact with each other.

[0046] In this embodiment, the side surface 12b of the protrusion 12 (the inner surface of the step 11) and the front surface 20a of the submount 20 are close to each other but are not in direct contact with each other. Specifically, the side surface 12b of the protrusion 12 (the inner surface of the step 11) and the front surface 20a of the submount 20 are connected only via a thin bonding member 80.

[0047] Here, the effects of the semiconductor laser light emitting device 1 according to this embodiment will be described in comparison with the semiconductor laser light emitting device 1X of Comparative Example 1 using Figures 3 and 4. Figure 3 is a cross-sectional view showing the configuration and heat dissipation path of the semiconductor laser light emitting device 1X of Comparative Example 1. Figure 4 is a cross-sectional view showing the configuration and heat dissipation path of the semiconductor laser light emitting device 1 according to this embodiment. Note that in Figures 3 and 4, arrows indicate the heat dissipation path of heat generated in the semiconductor laser 30.

[0048] 3, the semiconductor laser light emitting device 1X of Comparative Example 1 has a structure in which the step 11 is not formed on the mounting substrate 10X, unlike the semiconductor laser light emitting device 1 according to the present embodiment. Specifically, in the semiconductor laser light emitting device 1X of Comparative Example 1, the protrusion 12 is not formed on the mounting substrate 10X.

[0049] In the semiconductor laser light emitting device 1X of Comparative Example 1 configured as described above, when laser light is emitted from the semiconductor laser 30 and heat is generated in the semiconductor laser 30, the heat generated in the semiconductor laser 30 is conducted to the mounting substrate 10X via the heat dissipation path shown in Figure 3.

[0050] However, in the semiconductor laser light emitting device 1X of Comparative Example 1, if the current flowing through the semiconductor laser 30 is increased to increase the output power, the amount of heat generated by the semiconductor laser 30 increases, causing the temperature of the semiconductor laser 30 to rise, resulting in a decrease in the output of the laser light emitted from the semiconductor laser 30 and a decrease in the reliability of the semiconductor laser 30.

[0051] In particular, in the semiconductor laser light emitting device 1X of Comparative Example 1, the semiconductor laser 30 is configured to protrude from the front surface 20a of the submount 20, so that heat generated near the front end surface 30a of the semiconductor laser 30 is less likely to be conducted to the mounting substrate 10 than other portions. Therefore, in the semiconductor laser light emitting device 1X of Comparative Example 1, the temperature of the semiconductor laser 30 on the front surface 20a side rises significantly.

[0052] In contrast, in the semiconductor laser light emitting device 1 according to this embodiment, as shown in FIG. 4, a step 11 is formed on the mounting substrate 10, and the side surface 12b of the convex portion 12, which is the inner surface of the step 11, is in thermal contact with the front surface 20a of the submount 20.

[0053] In the semiconductor laser light-emitting device 1 configured as described above, heat generated in the semiconductor laser 30 is conducted to the mounting substrate 10 via the heat dissipation path shown in FIG. 4 . That is, in the semiconductor laser light-emitting device 1 according to this embodiment, a heat dissipation path via the step 11 (protrusion 12) located on the light-emitting side of the semiconductor laser 30 is added to the semiconductor laser light-emitting device 1X of Comparative Example 1. In this added heat dissipation path, heat generated near the front end face 30a of the semiconductor laser 30 is conducted to the vicinity of the front face 20a of the submount 20, and then conducted from the front face 20a of the submount 20 to the inner side surface of the step 11 (side surface 12b of the protrusion 12) and then to the mounting substrate 10. That is, in the semiconductor laser light-emitting device 1 according to this embodiment, heat generated in the semiconductor laser 30 can be efficiently conducted from the front face 20a of the submount 20 to the mounting substrate 10.

[0054] As a result, even if the front end face 30a of the semiconductor laser 30 protrudes from the front face 20a of the submount 20, heat generated near the front end face 30a of the semiconductor laser 30 can be efficiently conducted to the mounting substrate 10. Furthermore, even if the semiconductor laser 30 does not protrude from the front face 20a of the submount 20, heat generated near the front end face 30a of the semiconductor laser 30 can be efficiently conducted to the mounting substrate 10, thereby reducing the temperature near the front end face 30a of the semiconductor laser 30.

[0055] As described above, the semiconductor laser light emitting device 1 according to this embodiment includes the mounting substrate 10, which is a mounting base having the step 11, the submount 20 arranged above the bottom surface of the step 11, and the semiconductor laser 30 arranged on the submount 20, and a first side surface, which is one of the inner surfaces of the step 11 (in this embodiment, the side surface 12b of the protrusion 12), is in thermal contact with the front surface 20a of the submount 20. In other words, in the semiconductor laser light emitting device 1 according to this embodiment, the step 11 (the protrusion 12) is used as a heat dissipation path, and the inner surface of this heat dissipating step 11 (the side surface 12b of the protrusion 12) is in thermal contact with the front surface 20a of the submount 20.

[0056] This configuration allows the heat generated in the semiconductor laser 30 to be efficiently conducted to the mounting substrate 10 via the submount 20. Therefore, even if the current flowing through the semiconductor laser 30 is increased to increase the output power, it is possible to prevent a decrease in the output of the laser light emitted from the semiconductor laser 30 and a decrease in the reliability of the semiconductor laser 30.

[0057] Moreover, in the semiconductor laser light emitting device 1 according to this embodiment, the inner side surface of the step 11 (the side surface 12 b of the protrusion 12 ) and the front surface 20 a of the submount 20 face each other.

[0058] This allows the step 11 formed on the mounting substrate 10 to be used as a reference for aligning the submount 20 and the semiconductor laser 30 with respect to the mounting substrate 10. For example, when mounting the submount 20 with the semiconductor laser 30 mounted on the mounting substrate 10, the submount is typically pressed onto the mounting substrate via an uncured bonding material, and then cured and bonded by heating in an oven, for example. However, in this embodiment, the submount 20 with the semiconductor laser 30 mounted thereon is pressed against the inner surface of the step 11 (the side surface 12 b of the convex portion 12), thereby enabling the submount 20 with the semiconductor laser 30 mounted thereon to be mounted with high precision at a predetermined position on the mounting substrate 10. In other words, the step 11 formed on the mounting substrate 10 can regulate the positions of the submount 20 and the semiconductor laser 30 in the horizontal direction of the substrate. Specifically, an uncured bonding material 80 is placed on the mounting substrate 10, and the submount 20 is pressed onto the uncured bonding material from above, and then pressed toward the step 11 to regulate its position. The bonding material 80 is then cured in this state to achieve a bonded state. This improves the mounting accuracy of the semiconductor laser 30 on the mounting substrate 10. Therefore, the semiconductor laser 30 can be mounted on the mounting substrate 10 via the submount 20 with high accuracy.

[0059] As described above, in the semiconductor laser light emitting device 1 according to this embodiment, the step 11 (protrusion 12) provided on the mounting substrate 10 can be used not only for heat dissipation but also for alignment.

[0060] As described above, according to the semiconductor laser light emitting device 1 of this embodiment, the heat generated in the semiconductor laser 30 can be efficiently conducted to the mounting substrate 10 via the submount 20, and the semiconductor laser 30 can be mounted with high precision on the mounting substrate 10. In other words, it is possible to achieve both improved heat dissipation of the semiconductor laser 30 and improved mounting precision.

[0061] Furthermore, in the semiconductor laser light emitting device 1 according to this embodiment, the position of the upper end of the inner surface of the step 11 of the mounting substrate 10 (side surface 12b of the convex portion 12) is the same as or lower than the position of the upper end of the front surface 20a of the submount 20. In other words, the height of the portion of the upper surface 12a of the convex portion 12, which is the upper surface of the step 11, on the submount 20 side is equal to or lower than the height of the submount 20.

[0062] This configuration ensures an optical path for the light emitted from the semiconductor laser 30. In other words, although the light (laser light) emitted from the semiconductor laser 30 spreads in the vertical direction, this configuration makes it possible to prevent the light emitted from the semiconductor laser 30 from being blocked by the steps 11 (protrusions 12). In this way, the semiconductor laser light-emitting device 1 according to this embodiment can improve the heat dissipation of the semiconductor laser 30 while ensuring an optical path for the light emitted from the semiconductor laser 30.

[0063] In this case, the distance from the lower surface 20d of the submount 20 to the upper end of the inner surface of the step 11 (side surface 12b of the protrusion 12) is preferably 40% to 100% of the distance from the lower surface 20d of the submount body 21 to the upper surface 20c of the submount body 21. In other words, the distance from the lower surface 20d of the submount body 21 to the uppermost position of the upper surface of the step 11 (upper surface 12a of the protrusion 12) is preferably 40% to 100% of the thickness of the submount body 21. If this distance exceeds 100% of the thickness of the submount body 21, the bonding member 80 between the protrusion 12 and the submount body 21 may rise when they are pressed together, potentially blocking the optical path. On the other hand, if this distance is less than 40% of the thickness of the submount body 21, the effect of improving heat dissipation will be insignificant.

[0064] This configuration can further prevent the light emitted from the semiconductor laser 30 from being blocked by the step 11 (protrusion 12).

[0065] In the semiconductor laser light emitting device 1 according to this embodiment, the inner side surface of the step 11 of the mounting substrate 10 is perpendicular to the bottom surface of the step 11. In this embodiment, the side surface 12b of the convex portion 12, which is the inner side surface of the step 11, and the first main surface 10a of the mounting substrate 10, which is the bottom surface of the step 11, are perpendicular to each other.

[0066] This configuration allows the entire inner surface of the step 11 (the side surface 12 b of the protrusion 12) and the entire bottom surface of the step 11 (the first main surface 10 a of the mounting substrate 10) to be in close contact with each other, further improving the heat dissipation of the semiconductor laser 30. Furthermore, if the side surface 12 b of the protrusion 12 and the first main surface 10 a of the mounting substrate 10 are perpendicular to each other, the submount 20 can be prevented from shifting up and down or rotating vertically due to the inclination of the contact surface of the step 11 during the process of pressing the submount 20 against the inner surface of the step 11 when bonding the submount 20 to the mounting substrate 10. Note that, for example, if the submount 20 is misaligned by 5 degrees from the vertical, the force pressing the submount 20 horizontally against the inner surface of the step 11 is converted into an upward force of approximately tan 5 degrees, or approximately 9%, due to the inclination of the end surface. However, this force is smaller than the pressing force when the submount is mounted, and therefore does not lead to significant lifting of one side of the submount 20. In other words, this degree of deviation from the perpendicular does not reduce the mounting accuracy of the submount 20.

[0067] In the semiconductor laser light emitting device 1 according to this embodiment, the inner side surface of the step 11 of the mounting substrate 10 (side surface 12b of the protrusion 12) and the front surface 20a of the submount 20 are parallel to each other.

[0068] This configuration allows the entire inner surface of the step 11 (the side surface 12b of the protrusion 12) to be in close contact with the entire front surface 20a of the submount 20, further improving the heat dissipation of the semiconductor laser 30. In particular, heat generated near the front end surface 30a of the semiconductor laser 30 can be effectively dissipated. Note that, for example, if there is an angle difference of 5 degrees, and the length of the portion where the side surface 12b of the protrusion 12 (the inner surface of the step 11) faces the front surface 20a of the submount 20 is 160 μm, the gap between the step 11 and the submount 20 at the opposite end compared to the side where the step 11 and the submount 20 meet will be 14 μm, but this level of gap does not significantly affect the heat dissipation effect.

[0069] (Variation 1 of Embodiment 1) Next, Variation 1 of Embodiment 1 will be described with reference to Figures 5A, 5B, and 5C. Figures 5A, 5B, and 5C are diagrams showing a portion of semiconductor laser light emitting device 1A according to Variation 1 of Embodiment 1, and are a cross-sectional view, a top view, and a perspective view, respectively, of the portion of semiconductor laser light emitting device 1A. Note that Figures 5A, 5B, and 5C correspond to Figures 2A, 2B, and 2C, which show a portion of semiconductor laser light emitting device 1 according to the above-mentioned embodiment 1.

[0070] 5A to 5C, the semiconductor laser light emitting device 1A according to this modification has a different shape of the step 11 from the semiconductor laser light emitting device 1 according to the above-described embodiment 1. Specifically, in the semiconductor laser light emitting device 1 according to the above-described embodiment 1, the step 11 is formed by providing a rectangular parallelepiped (quadrature prism) protrusion 12 on the mounting substrate 10, but in the semiconductor laser light emitting device 1A according to this modification, the step 11 is formed by providing a triangular prism protrusion 12A laid down on the mounting substrate 10A.

[0071] As a result, in this modification, the upper surface 12a of the protrusion 12A, which is the upper surface of the step 11, becomes lower with increasing distance from the submount 20. Specifically, the upper surface 12a of the protrusion 12A is a flat, inclined surface. In this modification, the protrusion 12A is a triangular prism whose cross section has a right-angled triangle shape. Specifically, the protrusion 12A is provided so that the right angle of the right-angled triangle is located on the submount 20 side.

[0072] 5A , if θ1 is half the vertical beam divergence angle of the light emitted from semiconductor laser 30 and θ2 is the angle between upper surface 12a of convex portion 12A, which is the upper surface of step 11 of mounting substrate 10A, and the upper surface of submount body 21 of submount 20 (i.e., the tilt angle of convex portion 12A), then it is preferable that θ1<θ2. Note that in this modification, the upper surface of submount body 21 is parallel to the lower surface of semiconductor laser 30, and therefore the tilt angle θ2 of convex portion 12A is the angle between the upper surface of step 11 (upper surface 12a of convex portion 12A) and the lower surface of semiconductor laser 30.

[0073] The inclination angle θ2 of the convex portion 12A is preferably greater than 0° and not greater than 80°, more preferably not greater than 60°, and even more preferably not greater than 45°. There is no particular lower limit to the inclination angle θ2, but the inclination angle θ2 is preferably not less than 30°. The most preferable inclination angle θ2 is 45°. In this modification, the half angle θ1 of the vertical beam divergence angle of the light emitted from the semiconductor laser 30 is 23°, and the inclination angle θ2 is 45°.

[0074] Furthermore, the cross-sectional triangular shape of the convex portion 12A is not particularly limited, but as an example, when the thickness of the submount body 21 is 200 μm, the cross-sectional shape of the convex portion 12A is a right-angled isosceles triangle (tilt angle θ2 = 45°) with a step height of 200 μm and a step width (bottom surface) of 200 μm, or a right-angled triangle (tilt angle θ2 = 30°) with a step height of 200 μm and a step width of 346 μm.

[0075] The semiconductor laser light emitting device 1A according to this modification has the same configuration as the semiconductor laser light emitting device 1 according to the first embodiment, except that the step 11 is formed by the triangular prism-shaped protrusion 12A.

[0076] Therefore, in this modification as well, the side surface 12b of the protrusion 12A, which is the inner surface of the step 11, is in thermal contact with the front surface 20a of the submount 20. Furthermore, in this modification as well, the side surface 12b of the protrusion 12A, which is the inner surface of the step 11, and the front surface 20a of the submount 20 face each other.

[0077] With this configuration, in the semiconductor laser light emitting device 1A according to this modified example, as in the semiconductor laser light emitting device 1 according to the first embodiment, the heat generated in the semiconductor laser 30 can be efficiently conducted to the mounting substrate 10A via the submount 20, and the semiconductor laser 30 can be mounted on the mounting substrate 10A with high precision.

[0078] In this modification, the upper surface 12 a of the protrusion 12 A, which is the upper surface of the step 11 , becomes lower with increasing distance from the submount 20 .

[0079] Since the light emitted from the semiconductor laser 30 expands in the vertical direction as it moves away from the submount, this configuration can prevent the light emitted from the semiconductor laser 30 from being blocked by the step 11 (protrusion 12A). In this way, the semiconductor laser light emitting device 1A according to this modification can improve the heat dissipation of the semiconductor laser 30 while ensuring the optical path of the light emitted from the semiconductor laser 30.

[0080] In this case, the angle formed by the upper surface of the step 11 (upper surface 12a of the protrusion 12A) and the upper surface 20c of the submount 20 is preferably 45° or less. Since heat is generally transferred in a direction within 45° of the main heat conduction direction (downward in this case), heat dissipation is limited when the angle formed above is greater than 45°.

[0081] This configuration makes it possible to maintain the heat dissipation properties of the semiconductor laser 30 by utilizing the step 11 (protrusion 12A), while further preventing the light emitted from the semiconductor laser 30 from being blocked by the step 11 (protrusion 12A).

[0082] The angle θ2 between the upper surface of the step 11 (upper surface 12a of the protrusion 12A) and the upper surface 20c of the submount 20 is preferably equal to or less than half the vertical beam divergence angle θ1 of the light emitted from the semiconductor laser 30.

[0083] This configuration can reliably prevent the light emitted from the semiconductor laser 30 from being blocked by the step 11 (the convex portion 12A).

[0084] In this modification, the upper surface 12a of the protrusion 12A is a flat inclined surface, but this is not limited to this as long as the upper surface 12a of the protrusion 12A becomes lower with increasing distance from the submount 20. For example, the upper surface 12a of the protrusion 12A may be configured to become lower in a stepped manner.

[0085] (Variation 2 of Embodiment 1) Next, Variation 2 of Embodiment 1 will be described with reference to Figures 6A, 6B, and 6C. Figures 6A, 6B, and 6C are diagrams showing a portion of semiconductor laser light emitting device 1B according to Variation 2 of Embodiment 1, and are a cross-sectional view, a top view, and a perspective view, respectively, of a portion of semiconductor laser light emitting device 1B. Note that Figures 6A, 6B, and 6C correspond to Figures 2A, 2B, and 2C, which show a portion of semiconductor laser light emitting device 1 according to Embodiment 1.

[0086] 6A to 6C, the semiconductor laser light emitting device 1B according to this modification has a different configuration of the mounting substrate 10B from the semiconductor laser light emitting device 1 according to the above-described embodiment 1. Specifically, in the semiconductor laser light emitting device 1 according to the above-described embodiment 1, the step 11 is formed by providing a convex portion 12 on the mounting substrate 10, but in the semiconductor laser light emitting device 1B according to this modification, the mounting substrate 10B has a first member 101 and a second member 102, and the step 11 is formed by placing the second member 102 on the first member 101.

[0087] The first member 101 is a base substrate of the mounting substrate 10B. The second member 102 is an additional member that is additionally installed on the first member 101. In this modification, the first member 101 is a rectangular plate-shaped substrate with a constant thickness, and the second member 102 is a bar-shaped rectangular parallelepiped (quadrature prism). The second member 102 can have the same shape as the protrusion 12 in the first embodiment.

[0088] The first member 101 and the second member 102 are made of different materials. The first member 101 and the second member 102 may be made of the same material as the mounting substrate 10 in the first embodiment. As an example, the first member 101 is a copper substrate made of copper. The second member 102 may be made of a material having a higher thermal conductivity than the first member 101, but is not limited to this.

[0089] The semiconductor laser light emitting device 1B according to this modified example has the same configuration as the semiconductor laser light emitting device 1 in the first embodiment, except that the mounting substrate 10B is composed of a first member 101 and a second member 102.

[0090] Therefore, in this modification as well, the side surface 102b of the second member 102, which is the inner surface of the step 11, is in thermal contact with the front surface 20a of the submount 20. Furthermore, in this modification as well, the side surface 102b of the second member 102, which is the inner surface of the step 11, and the front surface 20a of the submount 20 face each other.

[0091] With this configuration, in the semiconductor laser light emitting device 1B according to this modified example, as in the semiconductor laser light emitting device 1 according to the first embodiment, the heat generated in the semiconductor laser 30 can be efficiently conducted to the mounting substrate 10B via the submount 20, and the semiconductor laser 30 can be mounted on the mounting substrate 10B with high precision.

[0092] Moreover, in the semiconductor laser light emitting device 1B according to this modified example, the mounting substrate 10B, which is an example of a mounting base, has a first member 101 and a second member 102 made of different materials, and the step 11 is formed by placing the second member 102 on top of the first member 101.

[0093] This configuration allows the material of the second member 102 to be selected as desired, and therefore the thermal conductivity of the second member 102 can be made higher than the thermal conductivity of the submount 20. This configuration allows the heat generated in the semiconductor laser 30 to be conducted to the mounting substrate 10B more efficiently than in a configuration in which, for example, the side surface of the submount 20 is shaped to have a flared bottom, and heat generated near the front end face 30a of the semiconductor laser 30 is conducted forward of the front end face 30a of the semiconductor laser 30 within the submount 20 via a similar heat path.

[0094] In this case, the thermal conductivity of the second member 102 is preferably equal to or higher than the thermal conductivity of the submount 20. In this modification, the submount 20 is made of aluminum nitride, which has a thermal conductivity of approximately 150 W / (m / K), and therefore the thermal conductivity of the second member 102 is equal to or higher than 150 W / (m / K).

[0095] With this configuration, the heat generated near the front end face 30a of the semiconductor laser 30 and conducted to the submount 20 can be conducted more efficiently to the second member 102 and the first member 101. Therefore, the heat dissipation performance of the semiconductor laser 30 can be further improved.

[0096] In this modification, the shape of the second member 102 of the mounting substrate 10B is a quadrangular prism, similar to the convex portion 12 in the first embodiment, but is not limited to this. For example, the shape of the second member 102 may be a triangular prism, similar to the convex portion 12A in the first modification of the first embodiment, or may be another shape.

[0097] In addition, in this modification, the first member 101 and the second member 102 constituting the mounting substrate 10B are made of different materials, but this is not limiting. In other words, the first member 101 and the second member 102 may be made of the same material.

[0098] (Third Modification of First Embodiment) Next, a third modification of the first embodiment will be described with reference to Fig. 7. Fig. 7 is a cross-sectional view showing a part of a semiconductor laser light emitting device 1C according to the third modification of the first embodiment. Note that Fig. 7 corresponds to Fig. 2A showing a part of the semiconductor laser light emitting device 1 according to the first embodiment.

[0099] In the first embodiment, when the step 11 is formed on the mounting substrate 10 by cutting with a drill or a laser, pressing, or the like, the base portion of the inner surface of the step 11 may be curved, forming a step radius (step R) that serves as a corner radius (corner R) at the base portion of the step 11. That is, the inner surface and the bottom surface of the step 11 may not be perpendicular to each other, and the corners at the base portion of the step 11 may be rounded, forming a curved portion 13 that is curved in an arc-shaped cross section at the base portion of the step 11, as shown in FIG. 7 . For example, when the step 11 is formed by cutting with a drill, a step radius with a height of about 23 μm is formed as the curved portion 13; when the step 11 is formed by cutting with a press, a step radius with a height of about 10 μm is formed as the curved portion 13; and when the step 11 is formed by pressing, a step radius with a height of 30 μm is formed as the curved portion 13.

[0100] If a curved portion 13 (step radius) is formed at the base of the step 11 in this way, when the submount 20 is mounted on the mounting substrate 10C using the step 11 to restrict its position, the front surface 20a of the submount 20 may ride up on the curved portion 13, causing a tilt of the submount 20. In this case, the semiconductor laser 30 mounted on the submount 20 may also tilt, causing the semiconductor laser 30 to be mounted in an incorrect orientation relative to the mounting substrate 10C.

[0101] 7 , in the semiconductor laser light emitting device 1C of this modification, a groove 14 is formed so as to be dug into the mounting substrate 10C along the inner surface of the step 11 (side surface 12 b of the convex portion 12) of the mounting substrate 10C so that a curved portion 13 (step radius) may be formed at the base portion of the inner surface of the step 11. In other words, in this modification, the bottom surface of the step 11 is the bottom surface of the groove 14, and the bottom surface of the groove 14 is located below the first main surface 10 a of the mounting substrate 10C (mounting surface on which the submount 20 is mounted) of the mounting substrate 10C.

[0102] Moreover, the grooves 14 are formed along the longitudinal direction of the protrusions 12. In this case, in this modification, the longitudinal length of the grooves 14 is the same as the longitudinal length of the protrusions 12, but the longitudinal length of the grooves 14 may be longer than the longitudinal length of the protrusions 12.

[0103] Furthermore, the depth of the groove 14 is preferably equal to or greater than the height of the curved portion 13 (the step radius). In other words, the distance from the first main surface 10a of the mounting substrate 10C to the bottom surface of the groove 14 is preferably equal to or greater than the height of the curved portion 13 (the step radius). Taking into account the above-mentioned cutting process or press process, the depth of the groove 14 is preferably at least 10 μm or greater, and more preferably 30 μm or greater. In this modification, the depth of the groove 14 is 50 μm.

[0104] The semiconductor laser light emitting device 1C according to this modification has the same configuration as the semiconductor laser light emitting device 1 according to the first embodiment, except that the mounting substrate 10C has the groove 14 and the curved portion 13 formed therein.

[0105] Therefore, in this modification as well, the side surface 12b of the protrusion 12, which is the inner surface of the step 11, is in thermal contact with the front surface 20a of the submount 20. Furthermore, in this modification as well, the side surface 12b of the protrusion 12, which is the inner surface of the step 11, and the front surface 20a of the submount 20 face each other.

[0106] With this configuration, in the semiconductor laser light emitting device 1C of this modified example, as in the semiconductor laser light emitting device 1 of the first embodiment, the heat generated in the semiconductor laser 30 can be efficiently conducted to the mounting substrate 10C via the submount 20, and the semiconductor laser 30 can be mounted on the mounting substrate 10C with high precision.

[0107] In addition, in this modified example, a groove 14 is formed by digging into the mounting substrate 10C along the inner surface of the step 11 (side surface 12b of the convex portion 12) so that the depth is greater than or equal to the height of the curved portion 13 (step radius).

[0108] With this configuration, when a curved portion 13 (step radius) is formed at the base of the inner surface of the step 11, even if the submount 20 is mounted on the mounting substrate 10C using the step 11 to restrict the position of the submount 20, it is possible to prevent the front surface 20a of the submount 20 from climbing up onto the curved portion 13, causing the submount 20 to tilt. In other words, the groove 14 can be used as an escape groove to prevent the submount 20 from tilting. This allows the submount 20 and the semiconductor laser 30 mounted on the submount 20 to be mounted in the correct orientation relative to the mounting substrate 10C.

[0109] In this modification, the groove 14 is filled with the bonding member 80, but this is not limiting. However, filling the groove 14 with the bonding member 80 can improve the heat dissipation of the semiconductor laser 30. In other words, by filling the groove 14 with the bonding member 80, the heat generated in the semiconductor laser 30 can be conducted more efficiently from the submount 20 to the mounting substrate 10C than when the groove 14 is not filled with the bonding member 80.

[0110] (Fourth Modification of First Embodiment) Next, a fourth modification of the first embodiment will be described with reference to Fig. 8. Fig. 8 is a cross-sectional view showing a part of a semiconductor laser light emitting device 1D according to the fourth modification of the first embodiment. Note that Fig. 8 corresponds to Fig. 2A showing a part of the semiconductor laser light emitting device 1 according to the first embodiment.

[0111] As described above, when the step 11 is formed on the mounting substrate 10 by cutting, pressing, or the like, a curved portion 13 (step radius) may be formed at the base of the inner surface of the step 11, as shown in Fig. 8. As a result, when the submount 20 is mounted on the mounting substrate 10 using the step 11, the submount 20 may climb up onto the curved portion 13 at the base of the step 11, causing the submount 20 to tilt.

[0112] To address this issue, in the above-mentioned variant example 3, grooves 14 were formed in the mounting substrate 10C to prevent the submount 20 from riding up on the curved portion 13, but in this variant example, a spacer 90 is placed between the submount 20 and the mounting substrate 10 to prevent the submount 20 from riding up on the curved portion 13.

[0113] Specifically, the spacer 90 is disposed between the first main surface 10a (the lower surface of the step 11) of the mounting substrate 10 and the lower surface 20d of the submount 20. The first main surface 10a (the lower surface of the step 11) of the mounting substrate 10 and the lower surface 20d of the submount 20 are parallel to each other.

[0114] A front surface 90a of the spacer 90, which is the surface on the light-emitting side of the semiconductor laser 30, is spaced apart from the inner surface of the step 11 by at least the distance of the curved portion 13. In this case, the spacer 90 is preferably disposed such that the front surface 90a of the spacer 90 is spaced apart from the inner surface of the step 11 (the side surface 12b of the convex portion 12) by at least 10 μm, preferably 30 μm or more.

[0115] Furthermore, the thickness of the spacer 90 is equal to or greater than the height of the curved portion 13. Considering the above-mentioned cutting process or press process, the thickness of the spacer 90 should be at least 10 μm or more, and preferably 30 μm or more. In this modification, the thickness of the spacer 90 is 50 μm.

[0116] The spacer 90 is a flat plate-like material with a uniform thickness. The spacer 90 may be made of either a conductive material or an insulating material, but is preferably made of a material with high thermal conductivity. As an example, the spacer 90 is a metal plate made of a metal material such as copper or aluminum. The spacer 90 is fixed by the joining member 80.

[0117] Except for the spacer 90, the semiconductor laser light emitting device 1D according to this modification has the same configuration as the semiconductor laser light emitting device 1 according to the first embodiment.

[0118] Therefore, in this modification as well, the side surface 12b of the protrusion 12, which is the inner surface of the step 11, is in thermal contact with the front surface 20a of the submount 20. Furthermore, in this modification as well, the side surface 12b of the protrusion 12, which is the inner surface of the step 11, and the front surface 20a of the submount 20 face each other.

[0119] With this configuration, in the semiconductor laser light emitting device 1D of this modified example, as in the semiconductor laser light emitting device 1 of the first embodiment, the heat generated in the semiconductor laser 30 can be efficiently conducted to the mounting substrate 10 via the submount 20, and the semiconductor laser 30 can be mounted on the mounting substrate 10 with high precision.

[0120] In this modification, the spacer 90 is disposed so as to be spaced apart from the inner surface of the step 11 by the distance of the curved portion 13 , and the thickness of the spacer 90 is set to be equal to or greater than the height of the curved portion 13 .

[0121] With this configuration, even if a curved portion 13 (step radius) is formed at the base of the inner surface of the step 11 and the submount 20 is mounted on the mounting substrate 10 using the step 11, it is possible to prevent the front surface 20a of the submount 20 from climbing up onto the curved portion 13, causing the submount 20 to tilt. This allows the submount 20 and the semiconductor laser 30 mounted on the submount 20 to be mounted in the correct orientation relative to the mounting substrate 10.

[0122] In this modified example, the submount 20 is prevented from climbing up onto the curved portion 13 by placing a spacer 90 between the mounting substrate 10 and the submount 20, but it is also possible to prevent the submount 20 from climbing up onto the curved portion 13 without using the spacer 90.

[0123] For example, when the submount 20 is placed on the first main surface 10a of the mounting substrate 10 without the spacer 90, the submount 20 can be prevented from climbing up onto the curved portion 13 by separating the corner where the front surface 20a of the submount 20 intersects with the bottom surface 20d of the submount 20 from the mounting substrate 10. In this case, it is preferable to separate the front surface 20a of the submount 20 from the inner surface of the step 11 (the side surface 12b of the protrusion 12) by the amount of the curved portion 13.

[0124] Furthermore, in this modification and the above modification 3, the step 11 is formed by performing cutting or pressing on a part of the mounting substrate 10C, and as a result, a curved portion 13 (step radius) is formed at the base portion of the inner surface of the step 11. However, by manufacturing the mounting substrate 10B by joining the first member 101 and the second member 102 that are manufactured separately, as in the above modification 2, it is possible to avoid the formation of the curved portion 13 (step radius) at the base portion of the inner surface of the step 11 (the base portion of the side surface 102b of the second member 102), and therefore it is possible to avoid the submount 20 riding up on the curved portion 13.

[0125] Moreover, by rounding the corners of the submount 20 corresponding to the step radius more than the step radius, it is possible to prevent the submount 20 from climbing up onto the curved portion 13 .

[0126] (Embodiment 2) Next, a semiconductor laser light emitting device 2 according to embodiment 2 will be described with reference to Figures 9A, 9B, and 9C. Figures 9A, 9B, and 9C are diagrams showing a portion of the semiconductor laser light emitting device 2 according to embodiment 2, and are respectively a cross-sectional view, a top view, and a perspective view of the portion of the semiconductor laser light emitting device 2. Note that Figures 9A, 9B, and 9C correspond to Figures 2A, 2B, and 2C, which show a portion of the semiconductor laser light emitting device 1 according to embodiment 1.

[0127] As shown in Figures 9A to 9C, in the semiconductor laser light emitting device 2 of this embodiment, like the semiconductor laser light emitting device 1 of embodiment 1, a step 110 is formed by providing a convex portion 120 on the mounting substrate 100. However, the semiconductor laser light emitting device 2 of this embodiment differs from the semiconductor laser light emitting device 1 of embodiment 1 in the shapes of the step 110 and the convex portion 120, the electrode structure of the submount 200, and the connection form of the gold wire 73.

[0128] Specifically, in the first embodiment, the step 11 has only one inner side surface that faces the submount 20, but the step 110 in the present embodiment has two inner side surfaces that face the submount 200. More specifically, in the present embodiment, the protrusion 120 that constitutes the step 110 has two different side surfaces, a first side surface 120b and a second side surface 120c. The first side surface 120b of the protrusion 120 is a first side surface formed as one of the inner side surfaces of the step 110, and the second side surface 120c of the protrusion 120 is a second side surface formed as another inner side surface different from the first side surface of the step 110.

[0129] The first side surface 120b and the second side surface 120c of the protrusion 120 are formed to form a predetermined angle. In this embodiment, the first side surface 120b and the second side surface 120c of the protrusion 120 are connected to form a right angle that is approximately perpendicular. In other words, in a top view, the first side surface 120b and the second side surface 120c form a right angle. Note that the protrusion 120 has a planar upper surface 120a, similar to the protrusion 12 in the first embodiment.

[0130] The submount 200 has a front surface 200a, a rear surface 200b, a top surface 200c, and a bottom surface 200d, similar to the submount 20 in the first embodiment. The submount 200 also has side surfaces 200e and 200f.

[0131] In the semiconductor laser light emitting device 2 according to this embodiment, not only is there thermal contact between the first side surface (first side surface 120b of the convex portion 120), which is one of the inner surfaces of the step 110, and the front surface 200a of the submount 200, but there is also thermal contact between the second side surface (second side surface 120c of the convex portion 120), which is an inner surface different from the first side surface of the step 110, and the side surface 200e of the submount 200.

[0132] In this case, it is preferable that the first side surface of the step 110 (first side surface 120b of the protrusion 120) and the front surface 200a of the submount 200 are physically close to or in contact with each other. It is also preferable that the second side surface of the step 110 (second side surface 120c of the protrusion 120) and the side surface 200e of the submount 200 are physically close to or in contact with each other.

[0133] In this embodiment, the first side surface 120b of the protrusion 120 and the front surface 200a of the submount 200 are close to each other but are not in direct contact with each other. Specifically, the first side surface 120b of the protrusion 120 and the front surface 200a of the submount 200 are connected only via the bonding member 80. Similarly, the second side surface 120c of the protrusion 120 and the side surface 200e of the submount 200 are close to each other but are not in direct contact with each other. Specifically, the second side surface 120c of the protrusion 120 and the side surface 200e of the submount 200 are connected only via the bonding member 80.

[0134] As described above, in the semiconductor laser light emitting device 2 according to the present embodiment, the first side surface 120b of the protrusion 120 (the first side surface of the step 110) and the front surface 200a of the submount 200 are in thermal contact, and the second side surface 120c of the protrusion 120 (the second side surface of the step 110) and the side surface 200e of the submount 200 are in thermal contact. In other words, the two different inner side surfaces of the step 110 and the two different surfaces of the submount 200 face each other and are in thermal contact with each other.

[0135] With this configuration, when heat generated in the semiconductor laser 300 is conducted to the mounting substrate 100 by utilizing the step 110, the heat generated in the semiconductor laser 300 can be conducted in two different directions horizontal to the substrate. Specifically, the heat generated in the semiconductor laser 300 is conducted from the front surface 200a of the submount 200 to the mounting substrate 100 via the first side surface 120b of the convex portion 120, and also from the side surface 200e of the submount 200 to the mounting substrate 100 via the second side surface 120c of the convex portion 120. This allows the heat generated in the semiconductor laser 300 to be conducted to the mounting substrate 100 more efficiently than in the semiconductor laser light emitting device 1 according to the first embodiment.

[0136] Also in this embodiment, when mounting the submount 200 on the mounting substrate 100, the step 110 can be used to align the submount 200. Moreover, in this embodiment, the step 110 can be used to restrict the position of the submount 200 in two different directions horizontal to the substrate. Specifically, by pressing the front surface 200a of the submount 200 against the first side surface 120b of the convex portion 120 and pressing the side surface 200e of the submount 200 against the second side surface 120c of the convex portion 120, the submount 200 on which the semiconductor laser 300 is mounted can be mounted at a predetermined position on the mounting substrate 100. This makes it possible to improve the mounting accuracy of the semiconductor laser 300 on the mounting substrate 100 compared to the semiconductor laser light-emitting device 1 according to the first embodiment.

[0137] In this way, the semiconductor laser light emitting device 2 according to this embodiment can further improve the heat dissipation and mounting accuracy of the semiconductor laser 300 compared to the semiconductor laser light emitting device 1 according to the first embodiment.

[0138] The semiconductor laser light-emitting device 2 according to the present embodiment is also different from the semiconductor laser light-emitting device 1 according to the first embodiment in the arrangement of the semiconductor laser 300. Specifically, the semiconductor laser 300 is arranged offset to the left and right with respect to the submount 200. Specifically, the semiconductor laser 300 is arranged offset so as to be closer to the side surface 200e of the side surfaces 200e and 200f that face each other in the submount 200. For example, when the width of the submount 200 (the distance between the side surfaces 200f and 200e) is 1000 μm, the semiconductor laser 300 is arranged offset so that the distance between the side surface 200e of the submount 200 and the center of the semiconductor laser 300 is 300 μm in top view.

[0139] In this way, since the semiconductor laser 300 is disposed offset to the left and right, a first electrode 22a and a second electrode 22b are formed on the upper surface of the submount body 21 of the submount 200, and are arranged insulated and separated from each other on the left and right. In this embodiment, the electrodes of the submount 200 are separated from each other on the left and right, but a structure in which only the first electrode 22a is formed as in the first embodiment may also be used.

[0140] The semiconductor laser 300 is disposed on the first electrode 22 a. In this embodiment as well, the semiconductor laser 300 is mounted on the submount 200 by junction-down mounting, so that the first electrode 22 a is connected to the p-side electrode of the semiconductor laser 300. On the other hand, the second electrode 22 b is connected to the n-side electrode of the semiconductor laser 300 by a gold wire 73.

[0141] In this way, when the semiconductor laser 300 is arranged on the submount 200 with an offset to the left or right, as in this embodiment, it is preferable to bring the first side surface 120b of the convex portion 120 (the first side surface of the step 110) into thermal contact with the front surface 200a of the submount 200, and the second side surface 120c of the convex portion 120 (the second side surface of the step 110) into thermal contact with the side surface 200e of the submount 200 on the side that the semiconductor laser 300 approaches.

[0142] This allows the heat generated by the semiconductor laser 300 to be conducted to the mounting substrate 100 more efficiently, and also makes it possible to easily improve the mounting accuracy of the semiconductor laser 300 .

[0143] In this embodiment, the structures, materials, arrangements, etc. of the mounting substrate 100, submount 200, and semiconductor laser 300 can be appropriately adapted from the structures, materials, arrangements, etc. of the mounting substrate, submount, and semiconductor laser in the first embodiment and its modifications.

[0144] (Modification of Second Embodiment) Next, a modification of the second embodiment will be described with reference to Figures 10A, 10B, and 10C. Figures 10A, 10B, and 10C are diagrams showing a portion of a semiconductor laser light emitting device 2A according to a modification of the second embodiment, and are a cross-sectional view, a top view, and a perspective view, respectively, of the portion of the semiconductor laser light emitting device 2A. Note that Figures 10A, 10B, and 10C correspond to Figures 9A, 9B, and 9C, which show a portion of the semiconductor laser light emitting device 2 according to the second embodiment.

[0145] In the second embodiment, when the step 110 is formed in the mounting substrate 100 by cutting, pressing, or the like, the corner portion between the first side surface of the step 110 (first side surface 120b of the convex portion 120) and the second side surface of the step 110 (second side surface 120c of the convex portion 120) may be curved in a top view, forming a corner radius at the corner portion of the step 110. In other words, in a top view, the corner portion of the step 110 may not be a right angle, but may be rounded, forming a curved portion that is curved in an arc-shaped cross section at the corner portion of the step 110.

[0146] If a curved portion (corner radius) is formed at the corner of the step 110 in this way, when the submount 200 is mounted on the mounting substrate 100A using the step 110 to regulate its position, the front surface 200a of the submount 200 may ride up on the curved portion, causing the submount 200 to rotate horizontally. In this case, the semiconductor laser 300 mounted on the submount 200 may also rotate horizontally, causing the semiconductor laser 300 to be mounted in an incorrect orientation relative to the mounting substrate 100A.

[0147] 10B , in the semiconductor laser light emitting device 2A of this modification, a groove 140 is formed at the corner of the step 110 of the mounting substrate 100A in a top view, the groove 140 being larger than the curved portion (corner radius) formed at the corner of the step 110. In this modification, the groove 140 is formed by cutting out the corner of the step 110 so as to recess it in a circular shape and retreat from the corner in a top view.

[0148] In top view, the recession amount of groove 140 from each of first side surface 120b and second side surface 120c (i.e., the recession amount of groove 140 in two orthogonal directions to the horizontal direction) is at least 10 μm or more, and preferably 30 μm or more, taking into consideration the above-mentioned cutting process or press process, etc. In this modification, groove 140 is formed so as to be recessed 50 μm from each of first side surface 120b and second side surface 120c in top view, and to be 3 / 4 of a circle with a radius of 50 μm (a sector with a circumferential angle of 270°).

[0149] The semiconductor laser light emitting device 2A according to this modification has the same configuration as the semiconductor laser light emitting device 2 according to the second embodiment, except that a groove 140 is formed in the mounting substrate 100A.

[0150] Therefore, also in this modification, the first side surface 120b of the protrusion 120 (the first side surface of the step 110) and the front surface 200a of the submount 200 are in thermal contact, and the second side surface 120c of the protrusion 120 (the second side surface of the step 110) and the side surface 200e of the submount 200 are in thermal contact. In other words, the two different inner side surfaces of the step 110 and the two different surfaces of the submount 200 face each other and are in thermal contact.

[0151] With this configuration, in the semiconductor laser light emitting device 2A according to this modified example, as in the semiconductor laser light emitting device 2 according to the second embodiment, the heat generated in the semiconductor laser 300 can be efficiently conducted to the mounting substrate 100A via the submount 200, and the semiconductor laser 300 can be mounted on the mounting substrate 100A with high precision.

[0152] In this modification, grooves 140 are formed at the corners of the steps 110 of the mounting substrate 100A when viewed from above.

[0153] This configuration eliminates the curved portion (corner radius) at the corner of the step 110 of the mounting substrate 100A, so that even if the submount 200 is mounted on the mounting substrate 100A using the step 110 to restrict the position of the submount 200, it is possible to prevent the submount 200 from riding up on the curved portion and rotating horizontally. This allows the submount 200 and the semiconductor laser 300 mounted on the submount 200 to be mounted in the correct orientation relative to the mounting substrate 100A.

[0154] In this modified example, the submount 200 is prevented from climbing up onto the curved portion by forming a groove 140 at the corner of the step 110, but it is also possible to prevent the submount 200 from climbing up onto the curved portion without forming the groove 140.

[0155] For example, when the groove 140 is not formed in the mounting substrate 100C, even if a curved portion (corner radius) is formed at the corner of the step 110 in top view, the submount 200 can be prevented from climbing up onto the curved portion by separating the corner where the front surface 200a and the side surface 200e of the submount 200 intersect from the mounting substrate 100C. In this case, it is preferable to separate the corner of the submount 200 corresponding to the corner radius from the two inner side surfaces of the step 110 (the first side surface 120b and the second side surface 120c of the protrusion 120) by the amount of the curved portion, for example, by rounding the corner of the submount 200 corresponding to the corner radius more than the corner radius or by providing spacers 90 on the front surface 200a and the side surface 200e of the submount 200 as in Variation 4 of Embodiment 1.

[0156] Third Embodiment Next, a semiconductor laser light emitting device 3 according to a third embodiment will be described with reference to Figures 11A, 11B, and 11C. Figures 11A, 11B, and 11C are diagrams showing a portion of the semiconductor laser light emitting device 3 according to the third embodiment, and are respectively a cross-sectional view, a top view, and a perspective view of the portion of the semiconductor laser light emitting device 3. Figures 11A, 11B, and 11C correspond to Figures 2A, 2B, and 2C, which show a portion of the semiconductor laser light emitting device 1 according to the first embodiment.

[0157] As shown in FIGS. 11A to 11C, semiconductor laser light emitting device 3 in this embodiment further includes mirror 400 that reflects light emitted from semiconductor laser 30 in addition to semiconductor laser light emitting device 1 in the first embodiment.

[0158] The mirror 400 has a reflecting surface 401 that reflects incident light. In this embodiment, the mirror 400 is a rising mirror, and the reflecting surface 401 reflects the incident light so that the light rises upward.

[0159] The reflecting surface 401 of the mirror 400 is an inclined surface that is inclined with respect to the first main surface 10a of the mounting substrate 10. As an example, the inclination angle of the reflecting surface 401 with respect to the first main surface 10a of the mounting substrate 10 is 45 degrees. In this case, the light of the semiconductor laser 30 that is emitted in a direction parallel to the first main surface 10a of the mounting substrate 10 is reflected by the reflecting surface 401 of the mirror 400 and travels upward, which is a direction perpendicular to the first main surface 10a of the mounting substrate 10.

[0160] For this reason, although not shown, in this embodiment, unlike the first embodiment, the light-transmitting member 50 that transmits the light of the semiconductor laser 30 is arranged so as to cover the opening provided in the top cover, rather than the opening in the frame body 40.

[0161] Furthermore, the protrusion 12 provided on the mounting substrate 10 has a side surface 12d facing away from the side surface 12b. Because the protrusion 12 is a rectangular parallelepiped, the side surfaces 12b and 12d are parallel to each other and are the same rectangle. In this manner, if the side surface of the step 11, which is the side surface 12b of the protrusion 12, is defined as a first side surface, the mounting substrate 10 has a third side surface, which is the side surface 12d of the protrusion 12, that is a surface parallel to the first side surface.

[0162] The mirror 400 is in contact with the side surface 12d (third side surface) of the protrusion 12. Specifically, the lower end of the mirror 400 on the reflecting surface 401 side (semiconductor laser 30 side) abuts against the side surface 12d of the protrusion 12.

[0163] The mirror 400 is disposed in a position facing the submount 20. The submount 20 and the mirror 400 are disposed via the convex portion 12. Specifically, the submount 20 is disposed so as to abut against the side surface 12b of the convex portion 12, and the mirror 400 is disposed so as to abut against the side surface 12d of the convex portion 12. In other words, the submount 20 and the mirror 400 are disposed so as to sandwich the convex portion 12 therebetween.

[0164] The mirror 400 is bonded to the mounting substrate 10 by a bonding member 81. This allows the mirror 400 to be fixed to the mounting substrate 10. The bonding member 81 may be the same as the bonding member 80.

[0165] Except for the mirror 400, the semiconductor laser light emitting device 3 according to this embodiment has basically the same configuration as the semiconductor laser light emitting device 1 according to the first embodiment.

[0166] Therefore, in this embodiment as well, the side surface 12b of the convex portion 12, which is the inner surface of the step 11, is in thermal contact with the front surface 20a of the submount 20, and the side surface 12b of the convex portion 12, which is the inner surface of the step 11, faces the front surface 20a of the submount 20.

[0167] With this configuration, in the semiconductor laser light emitting device 3 according to this embodiment, as in the semiconductor laser light emitting device 1 according to the first embodiment, the step 11 (protrusion 12) can be used to efficiently conduct heat generated in the semiconductor laser 30 to the mounting substrate 10, and the semiconductor laser 30 can be mounted on the mounting substrate 10 with high precision.

[0168] Moreover, in the semiconductor laser light emitting device 3 of this embodiment, the mirror 400 is in contact with the side surface 12 d of the protrusion 12 .

[0169] With this configuration, the step 11 formed on the mounting substrate 10 can be used as a reference not only for aligning the submount 20 and the semiconductor laser 30 with respect to the mounting substrate 10, but also for aligning the mirror 400 with respect to the mounting substrate 10. For example, when mounting the mirror 400 on the mounting substrate 10, the mirror 400 can be mounted at a predetermined position on the mounting substrate 10 by pressing the mirror 400 against the side surface 12d of the protrusion 12. In other words, the step 11 (protrusion 12) formed on the mounting substrate 10 can regulate the position of the mirror 400 in the horizontal direction of the substrate. This can also improve the mounting accuracy of the mirror 400 with respect to the mounting substrate 10.

[0170] In this way, in the semiconductor laser light emitting device 3 according to this embodiment, by utilizing the step 11 (protrusion 12) provided on the mounting substrate 10, not only the positions of the semiconductor laser 30 and the submount 20 can be regulated, but also the position of the mirror 400 can be regulated.

[0171] Here, a simulation was performed on the heat dissipation effect of the semiconductor laser light emitting device 3 according to the present embodiment, and the results will be described in comparison with the semiconductor laser light emitting device 3X of Comparative Example 2. Fig. 12 is a cross-sectional view showing the configuration of the semiconductor laser light emitting device 3X of Comparative Example 2. Fig. 13 is a cross-sectional view showing the configuration of the semiconductor laser light emitting device 3 according to the third embodiment.

[0172] As shown in Fig. 12, the semiconductor laser light emitting device 3X of Comparative Example 2 has a structure in which the step 11 is not formed on the mounting substrate 10X, unlike the semiconductor laser light emitting device 3 according to the present embodiment shown in Fig. 13. Specifically, in the semiconductor laser light emitting device 3X of Comparative Example 2, the protrusion 12 is not formed on the mounting substrate 10X.

[0173] 13, a spacer 90 is disposed between the submount 20 and the mounting substrate 10. Similarly, in the semiconductor laser light emitting device 3X of Comparative Example 2, a spacer 90 is disposed between the submount 20 and the mounting substrate 10X.

[0174] In this simulation, the mounting substrate 10 and the mounting substrate 10X were copper substrates, the submount body 21 of the submount 20 was a rectangular parallelepiped aluminum nitride plate having a length of 1400 μm in the longitudinal direction of the semiconductor laser 30, a length of 1000 μm in the direction perpendicular to the longitudinal direction of the semiconductor laser 30, and a thickness of 200 μm, the electrode 22 of the submount 20 was a thick copper film having a thickness of 50 μm, the spacer 90 was also a thick copper film having a thickness of 50 μm, and the semiconductor laser 30 was a GaN semiconductor laser element having a length of 1200 μm in the resonator length direction, a length of 150 μm in the direction perpendicular to the resonator length direction, and a thickness of 90 μm. The beam divergence angle of the semiconductor laser 30 was 46°. The semiconductor laser 30 was mounted on the submount 20 at a position where the distance between the front end face 30a and the front surface 20a of the submount 20 (protrusion from the submount) was 10 μm, and the horizontal distance from the front end face 30a of the semiconductor laser 30 to the reflecting surface 401 of the mirror 400 was 320 μm. The distance from the rear end face 30b of the semiconductor laser 30 to the rear surface 20b of the submount 20 was 210 μm. The protrusion 12 of the mounting substrate 10 in FIG. 13 was a rectangular copper block with a cross-sectional height of 200 μm and a width of 200 μm. The length of the protrusion 12 was 1000 μm so as to cover the entire lateral width of the front surface 20a of the submount 20.

[0175] Then, a heat transfer analysis was performed on the semiconductor laser light emitting device 3X of Comparative Example 2 and the semiconductor laser light emitting device 3 according to the present embodiment, and it was found that the maximum temperature of the semiconductor laser 30 in the semiconductor laser light emitting device 3X of Comparative Example 2 was 59.1°C. On the other hand, the maximum temperature of the semiconductor laser 30 in the semiconductor laser light emitting device 3 according to the present embodiment was 57.8°C. Thus, it was found that the maximum temperature of the semiconductor laser 30 could be reduced by approximately 1.3°C by forming the convex portion 12 on the mounting substrate 10.

[0176] Furthermore, when the input power to the semiconductor laser 30 was 7.4 W and the ambient temperature was 25° C., the thermal resistance (= (maximum temperature - 25° C.) / input power) was calculated for the semiconductor laser light emitting device 3X of Comparative Example 2 and the semiconductor laser light emitting device 3 according to this embodiment. The thermal resistance of the semiconductor laser light emitting device 3X of Comparative Example 2 was approximately 4.61 [° C. / W]. On the other hand, the thermal resistance of the semiconductor laser light emitting device 3 according to this embodiment was approximately 4.44 [° C. / W]. As described above, it was found that by forming the convex portion 12 on the mounting substrate 10, the maximum temperature of the semiconductor laser 30 could be reduced by 1.3° C., and as a result, the thermal resistance could be reduced by approximately 0.17 [° C. / W]. In other words, it was found that the semiconductor laser light emitting device 3 according to this embodiment can efficiently conduct heat generated in the semiconductor laser 30 to the mounting substrate 10.

[0177] As described above, in the semiconductor laser light emitting device 3 according to this embodiment, the semiconductor laser 30 has excellent heat dissipation properties.

[0178] In this embodiment, the positions of the semiconductor laser 30 and the submount 20 are restricted by one step 11 (protrusion 12), but this is not limiting. For example, a step (protrusion or recess) may be provided on the mounting substrate 10 in addition to the step 11 (protrusion 12), and the position of the mirror 400 may be restricted by this step (protrusion or recess). In this case, the other step (protrusion or recess) may be provided on the opposite side of the reflecting surface 401 of the mirror 400 (behind the mirror 400).

[0179] In addition, in the present embodiment, the mirror 400 is mounted on the mounting substrate 10 by contacting the side surface 12d of the protrusion 12, but this is not limiting. Specifically, the mirror 400 may be disposed without contacting the side surface 12d of the protrusion 12, in accordance with the distance from the semiconductor laser 30, the attitude of the semiconductor laser 30, and the like.

[0180] 14 , when the semiconductor laser 30 protrudes up to the convex portion 12 (step 11), the mirror 400 may be disposed away from the convex portion 12 in order to set the distance between the front end face 30a of the semiconductor laser 30 and the mirror 400 to a predetermined value. Specifically, when the front end face 30a of the semiconductor laser 30 protrudes by a distance d (e.g., 20 μm) from a predetermined reference position, the mirror 400 is disposed away from the side surface 12d of the convex portion 12 by the distance d (e.g., 20 μm).

[0181] 15 , when the semiconductor laser 30 is inclined with respect to the inner surface of the step 11 (side surface 12b of the convex portion 12) in a top view, the mirror 400 may be disposed at an angle with respect to the inner surface of the step 11 (side surface 12b of the convex portion 12) in accordance with the angle of the semiconductor laser 30, in order to reflect the light emitted from the semiconductor laser 30 in a predetermined direction. For example, when the semiconductor laser 30 is mounted with the front end face 30a of the semiconductor laser 30 inclined by 1.5° with respect to the side surface 12b of the convex portion 12 or the front surface 20a of the submount 20, the mirror 400 is disposed with the front surface of the mirror 400 also inclined by 1.5° with respect to the side surface 12b of the convex portion 12 or the front surface 20a of the submount 20.

[0182] The configurations of the first to third modifications of the first embodiment and the second embodiment can also be applied to this embodiment.

[0183] (Fourth Embodiment) Next, a semiconductor laser light emitting device 4 according to a fourth embodiment will be described with reference to Figures 16A and 16B. Figures 16A and 16B are diagrams showing a portion of the semiconductor laser light emitting device 4 according to the fourth embodiment, and are a top view and a perspective view, respectively, of the portion of the semiconductor laser light emitting device 4. Note that Figures 16A and 16B correspond to Figures 2B and 2C, which show a portion of the semiconductor laser light emitting device 1 according to the first embodiment.

[0184] 16A and 16B, the semiconductor laser light emitting device 4 according to this embodiment is formed into a multi-chip using a plurality of semiconductor lasers 30. This allows the semiconductor laser light emitting device 4 to have a high output.

[0185] Specifically, the semiconductor laser light emitting device 4 according to the present embodiment has a configuration in which the semiconductor laser light emitting device 1 according to the first embodiment has a plurality of submounts 20 and a plurality of semiconductor lasers 30. A plurality of semiconductor lasers 30 are disposed on each of the plurality of submounts 20. In other words, the plurality of submounts 20 and the plurality of semiconductor lasers 30 correspond one-to-one to each other.

[0186] 16A shows an example in which three submounts 20 and three semiconductor lasers 30 are arranged. That is, three sets of modules, each consisting of one semiconductor laser 30 and one submount 20, are arranged on the mounting substrate 10. These three sets of modules are arranged at equal intervals along the longitudinal direction of the protrusion 12. In this embodiment, the three sets of modules are arranged at equal intervals of 3.5 mm.

[0187] In each of the three sets of modules, two adjacent semiconductor lasers 30 are connected by a gold wire 74. In other words, the plurality of semiconductor lasers 30 are electrically connected in series.

[0188] Note that Fig. 16B shows two sets of modules out of the three sets of modules shown in Fig. 16A, and gold wires 74 are omitted from Fig. 16B.

[0189] As in the first embodiment, for each of the multiple submounts 20, the side surface 12b of the convex portion 12, which is the inner surface of the step 11, is in thermal contact with the front surface 20a of the submount 20. That is, the front surface 20a of each of the multiple submounts 20 is in thermal contact with the inner surface of the step 11 of the mounting substrate 10 (the side surface 12b of the convex portion 12). In this case, it is preferable that the front surface 20a of each submount 20 is physically close to or in contact with the inner surface of the step 11 (the side surface 12b of the convex portion 12). Also in this embodiment, for each of the multiple submounts 20, the inner surface of the step 11 (the side surface 12b of the convex portion 12) and the front surface 20a of the submount 20 face each other.

[0190] Here, the step 11, which faces the front faces 20a of the multiple submounts 20, is a single structure (rectangular parallelepiped). The side face 12b of this step 11 can be manufactured linearly. Therefore, by having the front faces 20a of the multiple submounts 20 face this single common side face 12b, the reference for positional regulation of the semiconductor laser 30 becomes unified, and it is possible to uniform the positional accuracy in one direction.

[0191] With this configuration, in the semiconductor laser light-emitting device 4 according to this embodiment, as in the semiconductor laser light-emitting device 1 according to the first embodiment, the heat generated in each semiconductor laser 30 can be efficiently conducted to the mounting substrate 10, and each semiconductor laser 30 can be mounted on the mounting substrate 10 with high precision.

[0192] (Variation 1 of Embodiment 4) Next, Variation 1 of Embodiment 4 will be described with reference to Figures 17A and 17B. Figures 17A and 17B are diagrams showing a portion of a semiconductor laser light emitting device 4A according to Variation 1 of Embodiment 4, and are a top view and a perspective view, respectively, of the portion of the semiconductor laser light emitting device 4A. Note that Figures 17A and 17B correspond to Figures 16A and 16B, which show a portion of the semiconductor laser light emitting device 4 according to the above-mentioned embodiment 4. Note that Figure 17B shows two sets of modules out of the three sets shown in Figure 17A.

[0193] The semiconductor laser light emitting device 4A according to this modification is obtained by applying the configuration of the semiconductor laser light emitting device 2 according to the second embodiment to the semiconductor laser light emitting device 4 according to the fourth embodiment.

[0194] Specifically, in the semiconductor laser light emitting device 4 according to the above-mentioned fourth embodiment, the step 11 has only one inner surface facing the submount 20, whereas in the semiconductor laser light emitting device 4A according to this modified example, the step 110 has two inner surfaces facing the submount 200.

[0195] In this modification, the protrusion 120 constituting the step 110 has two different side surfaces, a first side surface 120b and a second side surface 120c. The first side surface 120b of the protrusion 120 is a first side surface formed as one of the inner surfaces of the step 110, and the second side surface 120c of the protrusion 120 is a second side surface formed as another inner surface of the step 110 different from the first side surface.

[0196] In this modification, the first side surface 120b and the second side surface 120c of the protrusion 120 are connected to each other so as to be substantially perpendicular to each other, as in the second embodiment. However, in this modification, since multiple submounts 200 are arranged, the protrusion 120 has multiple first side surfaces 120b and multiple second side surfaces 120c.

[0197] Furthermore, similarly to the second embodiment, the semiconductor laser 300 is disposed offset so as to be closer to the side surface 200e of the side surfaces 200e and 200f that face each other on the submount 200.

[0198] In the semiconductor laser light emitting device 4 according to this modified example, as in the second embodiment, for each submount 200, a first side surface (first side surface 120b of the convex portion 120), which is one of the inner surfaces of the step 110, is in thermal contact with the front surface 200a of the submount 200, and a second side surface (second side surface 120c of the convex portion 120), which is an inner surface different from the first side surface of the step 110, is in thermal contact with the side surface 200e of the submount 200.

[0199] That is, each of the plurality of first side surfaces 120b of the protrusion 120 is in thermal contact with the front surface 200a of each of the plurality of submounts 200, and each of the plurality of second side surfaces 120c of the protrusion 120 is in thermal contact with the side surface 200e of each of the plurality of submounts 200. In particular, for each submount 200, the side surface 200e of the submount 200 located on the side closer to the semiconductor laser 300 after the semiconductor laser 300 is offset is in thermal contact with the second side surface 120c of the protrusion 120.

[0200] With this configuration, heat generated in each semiconductor laser 300 is conducted from the front surface 200a of each submount 200 to the mounting substrate 100 via the first side surface 120b of the convex portion 120, and also from the side surface 200e of each submount 200 to the mounting substrate 100 via the second side surface 120c of the convex portion 120. This allows the heat generated in the semiconductor laser 300 to be conducted to the mounting substrate 100 more efficiently than in the semiconductor laser light-emitting device 4 according to the fourth embodiment.

[0201] Moreover, in this modification, as in the second embodiment, the positions of the submounts 200 can be restricted in two different directions horizontal to the substrate by utilizing the steps 110. This makes it possible to improve the overall mounting accuracy of the semiconductor lasers 300 on the mounting substrate 100 in the two directions compared to the semiconductor laser light-emitting device 4 according to the fourth embodiment.

[0202] As described above, the semiconductor laser light emitting device 4A according to this modification can further improve the heat dissipation and mounting accuracy of the semiconductor laser 300 compared to the semiconductor laser light emitting device 4 according to the fourth embodiment.

[0203] The plurality of semiconductor lasers 300 may be electrically connected in series by gold wires or the like.

[0204] (Modification 2 of Embodiment 4) Next, Modification 2 of Embodiment 4 will be described with reference to Figures 18A and 18B. Figures 18A and 18B are diagrams showing a portion of a semiconductor laser light emitting device 4B according to Modification 2 of Embodiment 4, and are a top view and a perspective view, respectively, of the portion of the semiconductor laser light emitting device 4B. Note that Figures 18A and 18B correspond to Figures 16A and 16B, which show a portion of the semiconductor laser light emitting device 4 according to the above-mentioned embodiment 4.

[0205] The semiconductor laser light emitting device 4B according to this modification is obtained by applying the configuration of the semiconductor laser light emitting device 3 according to the third embodiment to the semiconductor laser light emitting device 4 according to the fourth embodiment.

[0206] 18A and 18B, semiconductor laser light emitting device 4B in the present embodiment further includes a plurality of mirrors 400 corresponding to each of the plurality of semiconductor lasers 30, in addition to semiconductor laser light emitting device 4 in the above-described fourth embodiment. The plurality of mirrors 400 are arranged in a one-to-one correspondence with the plurality of semiconductor lasers 30, and reflect light emitted from each of the plurality of semiconductor lasers 30.

[0207] Each mirror 400 is a rising mirror having a reflecting surface 401 that reflects incident light so that the light is raised upward, as in the third embodiment.

[0208] Each mirror 400 is in contact with a side surface 12d (third side surface) facing away from the side surface 12b of the protrusion 12. Specifically, the lower end of each mirror 400 on the reflecting surface 401 side (semiconductor laser 30 side) abuts against the side surface 12d of the protrusion 12.

[0209] Each mirror 400 is disposed in a position facing the corresponding submount 20. The pair of submounts 20 and mirrors 400 are disposed via the convex portion 12. Specifically, the submount 20 is disposed so as to abut against the side surface 12b of the convex portion 12, and the mirror 400 is disposed so as to abut against the side surface 12d of the convex portion 12. In other words, the pair of submounts 20 and mirrors 400 are disposed so as to sandwich the convex portion 12.

[0210] 18A, in this modification, nine sets of modules are arranged, each consisting of one semiconductor laser 30 and one submount 20. Specifically, the modules each consisting of the semiconductor laser 30 and the submount 20 are arranged in three rows and three columns. Therefore, nine mirrors 400 are arranged in three rows and three columns.

[0211] In this case, as shown in Fig. 18A, three protrusions 12 are provided on the mounting substrate 10. Three sets of modules each consisting of a semiconductor laser 30 and a submount 20 and a mirror 400 are arranged on each protrusion 12. Note that Fig. 18B illustrates two sets of modules out of the nine sets shown in Fig. 18A.

[0212] In this modified example, in each submount 20, the inner surface of the step 11 (side surface 12b of the convex portion 12) and the front surface 20a of the submount 20 are in thermal contact, and the inner surface of the step 11 (side surface 12b of the convex portion 12) and the front surface 20a of the submount 20 face each other.

[0213] With this configuration, in the semiconductor laser light emitting device 4B of this modified example, as in the semiconductor laser light emitting device 4 of the above-described fourth embodiment, the step 11 (protrusion 12) can be used to efficiently conduct heat generated in the semiconductor laser 30 to the mounting substrate 10, and the semiconductor laser 30 can be mounted on the mounting substrate 10 with high precision.

[0214] Furthermore, in the semiconductor laser light emitting device 4 of this modification, each mirror 400 is in contact with the side surface 12d of the protrusion 12, similar to the third embodiment.

[0215] With this configuration, the step 11 formed on the mounting substrate 10 can be used as a reference for aligning the submount 20 and the semiconductor laser 30 with respect to the mounting substrate 10, and can also be used as a reference for aligning the mirror 400 with respect to the mounting substrate 10. In other words, the step 11 (protrusion 12) formed on the mounting substrate 10 can regulate the position of the mirror 400 in the horizontal direction of the substrate. This allows the positional accuracy of the mirror 400 with respect to the mounting substrate 10 to be uniform in one direction.

[0216] (Other Modifications) Although the semiconductor laser light emitting device according to the present disclosure has been described above based on the embodiments, the present disclosure is not limited to the above-described embodiments.

[0217] For example, in the first embodiment and the like, the semiconductor laser light emitting device is a rectangular box-shaped package type, but is not limited to this. For example, as shown in Figure 19, the semiconductor laser light emitting device 5 may be a TO-CAN package type.

[0218] 19 , the semiconductor laser light emitting device 5 according to this modification includes a metal base 510 which is an example of a mounting base, a metal cap 520, and a light-transmitting member 530 attached to the cap 520. The submount 20 and the semiconductor laser 30 are housed in the cap 520.

[0219] The base 510 has a stem base 511 and a semi-cylindrical stem post 512 attached to the stem base 511. The stem base 511 and the stem post 512 are made of, for example, Cu.

[0220] The submount 20 on which the semiconductor laser 30 is mounted is supported by a base 510. More specifically, the submount 20 on which the semiconductor laser 30 is mounted is fixed to a stem post 512.

[0221] The stem post 512 has a step 11, similar to the first embodiment. Specifically, the stem post 512 has a protrusion 12, and the step 11 is formed by this protrusion 12.

[0222] The pair of lead pins 61 and 62 are provided on the stem base 511. Although not shown, the pair of lead pins 61 and 62 are electrically connected to a pair of electrodes of the semiconductor laser 30 via gold wires.

[0223] The semiconductor laser light emitting device 5 configured in this manner has the same effects as those of the first embodiment.

[0224] The configurations of the above-described first, second, third, and fourth embodiments and their modifications can also be applied to this modification.

[0225] Furthermore, in each of the above embodiments, the semiconductor laser 30 protrudes from the front surface 20a of the submount 20, but this is not limiting. The semiconductor laser 30 does not have to protrude from the front surface 20a of the submount 20. For example, the front end face 30a of the semiconductor laser 30 may be flush with the front surface 20a of the submount 20, or may be located at a position recessed from the front surface 20a of the submount 20.

[0226] In addition, this disclosure also includes forms obtained by applying various modifications that a person skilled in the art would conceive of to each embodiment and variant, and forms realized by arbitrarily combining the components and functions of each embodiment and variant within the scope that does not deviate from the intent of this disclosure.

[0227] The semiconductor laser light-emitting device according to the present disclosure is useful as a light source for products in various fields, such as image display devices such as projectors, automotive parts such as in-vehicle headlamps, lighting fixtures such as spotlights, or industrial equipment such as laser processing equipment, and is particularly useful as a light source for equipment that requires a relatively high optical output.

[0228] 1, 1A, 1B, 1C, 1D, 2, 2A, 3, 4, 4A, 4B, 5 Semiconductor laser light emitting device 10, 10A, 10B, 10C Mounting substrate 10a First main surface 10b Second main surface 11, 110 Step 12, 12A, 120 Convex portion 12a Top surface 12b, 12d Side surface 13 Curved portion 14, 140 Groove 20, 200 Submount 20a Front surface 20b Rear surface 20c Top surface 20d Bottom surface 21 Submount body 22 Electrode 22a First electrode 22b Second electrode 30, 300 Semiconductor laser 30a Front end surface 30b Rear end surface 40 Frame body 41 Opening 50 Light-transmitting member 61, 62 Lead pin 71, 72, 73, 74 Gold wires 80, 81 Bonding members 90 Spacer 90a Front surface 100, 100A Mounting substrate 101 First member 102 Second member 102b Side surface 120a Top surface 120b First side surface 120c Second side surface 200a Front surface 200b Rear surface 200c Top surface 200d Bottom surface 200e, 200f Side surface 400 Mirror 401 Reflecting surface 510 Base 511 Stem base 512 Stem post 520 Cap 530 Light-transmitting member

Claims

1. a mounting base having a step; a submount disposed above a bottom surface of the step; a semiconductor laser disposed on the submount; a first side surface which is one of inner sides of the step and a front surface which is a light emission side surface of the semiconductor laser in the submount are in thermal contact with each other; The upper surface of the step becomes lower with increasing distance from the submount. Semiconductor laser emitting device.

2. A mounting base having a step; a submount disposed above a bottom surface of the step; a semiconductor laser disposed on the submount; a first side surface which is one of inner sides of the step and a front surface which is a light emission side surface of the semiconductor laser in the submount are in thermal contact with each other; the mounting base has a first member and a second member made of different materials; the step is configured by disposing the second member on the first member, The thermal conductivity of the second member is equal to or greater than the thermal conductivity of the submount. Semiconductor laser emitting device.

3. A mounting base having a step; a submount disposed above a bottom surface of the step; a semiconductor laser disposed on the submount; a first side surface which is one of inner sides of the step and a front surface which is a light emission side surface of the semiconductor laser in the submount are in thermal contact with each other; Furthermore, a second side surface of the step, which is another inner side surface different from the first side surface, is in thermal contact with a side surface of the submount, a corner portion where the front surface and the side surface of the submount intersect is spaced apart from the mounting base; Semiconductor laser emitting device.

4. A mounting base having a step; a submount disposed above a bottom surface of the step; a semiconductor laser disposed on the submount; a first side surface which is one of inner sides of the step and a front surface which is a light emission side surface of the semiconductor laser in the submount are in thermal contact with each other; A curved portion is formed at a base portion of the first side surface of the step, a groove is formed along the first side surface of the step so as to dig into the mounting base, a bottom surface of the groove is located below a mounting surface of the mounting base on which the submount is mounted, The depth of the groove is equal to or greater than the height of the curved portion. Semiconductor laser emitting device.

5. A mounting base having a step; a submount disposed above a bottom surface of the step; a semiconductor laser disposed on the submount; a first side surface which is one of inner sides of the step and a front surface which is a light emission side surface of the semiconductor laser in the submount are in thermal contact with each other; a corner portion where the front surface of the submount and a lower surface of the submount intersect is spaced apart from the mounting base; Semiconductor laser emitting device.

6. A mounting base having a step; a submount disposed above a bottom surface of the step; a semiconductor laser disposed on the submount; a spacer disposed between the submount and the mounting base, a first side surface which is one of inner sides of the step and a front surface which is a light emission side surface of the semiconductor laser in the submount are in thermal contact with each other; A curved portion is formed at a base portion of the first side surface of the step, a front surface of the spacer that is a surface on the light emission side of the semiconductor laser is spaced apart from the first side surface of the step by at least the width of the curved portion; The thickness of the spacer is equal to or greater than the height of the curved portion. Semiconductor laser emitting device.

7. A mounting base having a step; a submount disposed above a bottom surface of the step; a semiconductor laser disposed on the submount; a mirror that reflects light emitted from the semiconductor laser, a first side surface which is one of inner sides of the step and a front surface which is a light emission side surface of the semiconductor laser in the submount are in thermal contact with each other; the mounting base has a third side surface parallel to the first side surface of the step, the mirror is in contact with the third side; Semiconductor laser emitting device.

8. A mounting base having a step; a submount disposed above a bottom surface of the step; a semiconductor laser disposed on the submount; a first side surface which is one of inner sides of the step and a front surface which is a light emission side surface of the semiconductor laser in the submount are in thermal contact with each other; the submount and the semiconductor laser are each a plurality of units, a plurality of the semiconductor lasers are disposed on each of the plurality of the submounts, the first side surface of the step is in thermal contact with the front surface of each of the plurality of submounts; Further, a plurality of mirrors corresponding to the plurality of semiconductor lasers are provided, the mounting base has a third side surface parallel to the first side surface of the step, Each of the plurality of mirrors is in contact with the third side. Semiconductor laser emitting device.

9. a position of an upper end of the first side surface at the step is equal to or lower than a position of an upper end of the front surface of the submount; 9. The semiconductor laser light emitting device according to claim 1.

10. an angle between an upper surface of the step and an upper surface of the submount is 45° or less; 10. The semiconductor laser light emitting device according to claim 1.

11. an angle between an upper surface of the step and an upper surface of the submount is equal to or smaller than half of a beam divergence angle in a vertical direction of light emitted from the semiconductor laser; 11. The semiconductor laser light emitting device according to claim 1.

12. the first side of the step and the front surface of the submount are parallel; 12. The semiconductor laser light emitting device according to claim 1.

13. The first side surface and the bottom surface of the step are perpendicular.

13. The semiconductor laser light emitting device according to claim 1.

14. The thermal conductivity of the second member is 150 [W / (m / K)] or more.

3. The semiconductor laser light emitting device according to claim 2.

15. Furthermore, each of a plurality of second side surfaces, which are inner side surfaces different from the first side surface of the step, is in thermal contact with a side surface of each of the plurality of submounts.

9. The semiconductor laser light emitting device according to claim 8.

16. A distance from a lower surface of the submount to an upper end of the first side surface at the step is greater than or equal to 40% and less than or equal to 100% of a distance from the lower surface of the submount to an upper surface of the submount.

10. The semiconductor laser light emitting device according to claim 9.