Laser module

Abstract

To miniaturize the laser module.SOLUTION: A laser module includes a laser element 21 having an exit 21d for emitting red light Lr, and a laser element 22 having an exit 22d for emitting green light Lg, and the laser element 21 and the laser element 22 are arranged such that the red light Lr and the green light Lg overlap each other.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a laser module. [Background technology]

[0002] There is known a laser module that combines laser beams output from a plurality of laser diodes and outputs the combined laser beam. For example, Patent Document 1 describes a laser module that includes a red laser diode, a green laser diode, a blue laser diode, and dichroic mirrors corresponding to the respective laser diodes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-133746 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the laser module described in Patent Document 1, a plurality of dichroic mirrors are provided to combine the laser beams output from the laser diodes, which may increase the size of the laser module.

[0005] The present disclosure describes a laser module that can be miniaturized. [Means for solving the problem]

[0006] A laser module according to an aspect of the present disclosure includes a first laser element having a first emission port for emitting a first laser beam, and a second laser element having a second emission port for emitting a second laser beam, the first laser element and the second laser element being arranged such that the first laser beam and the second laser beam overlap each other.

[0007] In this laser module, the first laser element and the second laser element are arranged so that the first laser light and the second laser light overlap each other. Therefore, the first laser light and the second laser light can be multiplexed without using optical components such as a dichroic mirror. As a result, the laser module can be made compact.

[0008] The laser module may further include a substrate having a mounting surface on which the first laser element is mounted. The distance from the mounting surface to the first exit may be different from the distance from the mounting surface to the second exit. In this case, even if the first exit and the second exit are brought closer to each other, the possibility that each laser light is blocked by the other laser element is reduced. Therefore, the angle between the emission direction of the first laser light and the emission direction of the second laser light can be reduced. This makes it possible to suppress the degree to which the first laser light and the second laser light diverge downstream of the position where the first laser light and the second laser light overlap in the emission direction.

[0009] The laser module may further include a carrier on which the second laser element is mounted. The carrier may be mounted on a mounting surface. In this case, the distance between the second emission port and the mounting surface varies depending on the thickness of the carrier. Therefore, the distance between the second emission port and the mounting surface can be changed simply by changing the thickness of the carrier, which makes it easy to adjust the distance between the second emission port and the mounting surface.

[0010] The first exit may be closer to the position where the first laser light and the second laser light overlap each other than the second exit. The second exit may be provided at a position closer to the first laser element than the center of the carrier in the arrangement direction of the first laser element and the second laser element. In this case, since the second exit is closer to the first exit, the angle between the emission direction of the first laser light and the emission direction of the second laser light can be made smaller. This makes it possible to suppress the degree to which the first laser light and the second laser light diverge downstream in the emission direction from the position where the first laser light and the second laser light overlap each other.

[0011] The laser module may further include a metal body that bonds the second laser element and the carrier. The metal body may include a rigid metal ball. In this case, since the metal ball has rigidity, the distance between the second emission port and the carrier is determined by the metal ball. Therefore, it is possible to easily adjust the distance between the second emission port and the carrier.

[0012] The second laser element may be disposed such that the emission direction of the second laser light is inclined with respect to the mounting surface. Since the distance from the mounting surface to the first emission opening is different from the distance from the mounting surface to the second emission opening, the emission direction of the second laser light is inclined with respect to the mounting surface, so that the overlapping portion of the first laser light and the second laser light can be expanded.

[0013] The beam divergence angle of the first laser element may be larger than the beam divergence angle of the second laser element. The first exit may be closer to the position where the first laser light and the second laser light overlap each other than the second exit. In this case, the first laser light is more likely to diverge than the second laser light. Therefore, by placing the first exit closer to the position where the first laser light and the second laser light overlap each other than the second exit, the degree of divergence of the laser light at the above position can be suppressed.

[0014] The laser module may further include an extraction member having a through hole through which the first laser light and the second laser light pass at an overlapping portion. In this case, the first laser light and the second laser light that are not included in the overlapping portion are blocked. This makes it possible to remove stray light.

[0015] The laser module may further include a first photodetector for monitoring the light intensity of the first laser light and a second photodetector for monitoring the light intensity of the second laser light. Each of the first laser element and the second laser element may be an edge-emitting type laser element. The first photodetector may be disposed on the opposite side of the first laser element from the emission direction of the first laser light. The second photodetector may be disposed on the opposite side of the second laser element from the emission direction of the second laser light. In this case, since the first laser element and the second laser element are edge-emitting type laser elements, they emit laser light from both the front and rear end faces. The ratio between the light intensity of the laser light emitted from the front end face and the light intensity of the laser light emitted from the rear end face is preset. Therefore, the light intensity of the laser light can be monitored without using an optical component for branching the laser light. As a result, the laser module can be further miniaturized.

[0016] The laser module may further include a third laser element having a third emission port for emitting a third laser light. The first laser light may be a red light, the second laser light may be a green light, and the third laser light may be a blue light. In this case, a full-color laser module can be realized. Effect of the Invention

[0017] According to each aspect and embodiment of the present disclosure, the laser module can be made smaller. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a laser module according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing the relationship between the overlapping portion of the laser light and the pinhole. [Diagram 3] FIG. 3 is a perspective view of the light source unit and the pinhole plate shown in FIG. [Figure 4] FIG. 4 is a plan view of the light source unit shown in FIG. [Diagram 5] FIG. 5 is a front view of the light source unit shown in FIG. [Figure 6] FIG. 6 is a diagram for explaining a method of manufacturing the light source unit shown in FIG. [Figure 7] FIG. 7 is a diagram for explaining a method of manufacturing the light source unit shown in FIG. [Figure 8] FIG. 8 is a diagram for explaining a method of manufacturing the light source unit shown in FIG. [Figure 9] FIG. 9 is a diagram for explaining a method of manufacturing the light source unit shown in FIG. [Figure 10] FIG. 10 is a diagram showing an example of bonding between a laser element and a carrier. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated descriptions are omitted. An XYZ coordinate system may be shown in each drawing. The Y-axis direction is a direction that intersects (for example, perpendicular to) the X-axis direction and the Z-axis direction. The Z-axis direction is a direction that intersects (for example, perpendicular to) the X-axis direction and the Y-axis direction.

[0020] A laser module according to an embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a diagram showing a schematic configuration of a laser module according to an embodiment. Fig. 2 is a diagram showing the relationship between an overlapping portion of laser light and a pinhole.

[0021] The laser module 1 shown in Fig. 1 is a module that emits laser light Lc. The laser module 1 is applied to, for example, a retinal projection device mounted on a near-eye wearable device. Examples of the near-eye wearable device include smart glasses such as AR (Augmented Reality) glasses, VR (Virtual Reality) glasses, and MR (Mixed Reality) glasses. The laser module 1 includes a light source unit 2, a photodetector 3 (first photodetector), a photodetector 4 (second photodetector), a photodetector 5, and a pinhole plate 6 (extraction member).

[0022] The light source unit 2 includes a laser element 21 (first laser element), a laser element 22 (second laser element), and a laser element 23 (third laser element). Each of the laser element 21, the laser element 22, and the laser element 23 is a bare chip. Each of the laser element 21, the laser element 22, and the laser element 23 is, for example, an edge-emitting laser element, and emits laser light from both the front and rear end faces. In each laser element, the ratio between the light intensity of the laser light emitted from the front end face and the light intensity of the laser light emitted from the rear end face is preset.

[0023] The laser element 21 emits red light Lr (first laser light) which is a laser light having a red wavelength from the front end face. The laser element 22 emits green light Lg (second laser light) which is a laser light having a green wavelength from the front end face. The laser element 23 emits blue light Lb (third laser light) which is a laser light having a blue wavelength from the front end face. The laser element 21, the laser element 22, and the laser element 23 are arranged so that the red light Lr, the green light Lg, and the blue light Lb overlap each other. Details of the light source unit 2 will be described later.

[0024] The photodetector 3 is an element for monitoring the light intensity of the red light Lr. The photodetector 3 is provided on the opposite side to the emission direction of the red light Lr from the laser element 21. In other words, the photodetector 3 faces the rear end face of the laser element 21. The photodetector 3 detects the light intensity of the laser light emitted from the rear end face of the laser element 21.

[0025] The photodetector 4 is an element for monitoring the light intensity of the green light Lg. The photodetector 4 is provided on the opposite side to the emission direction of the green light Lg from the laser element 22. In other words, the photodetector 4 faces the rear end face of the laser element 22. The photodetector 4 detects the light intensity of the laser light emitted from the rear end face of the laser element 22.

[0026] The photodetector 5 is an element for monitoring the light intensity of the blue light Lb. The photodetector 5 is provided on the opposite side to the emission direction of the blue light Lb from the laser element 23. In other words, the photodetector 5 faces the rear end face of the laser element 23. The photodetector 5 detects the light intensity of the laser light emitted from the rear end face of the laser element 23.

[0027] The pinhole plate 6 is an optical component for extracting a portion Lw where the red light Lr, the green light Lg, and the blue light Lb overlap each other. The pinhole plate 6 has a plate-like shape. The pinhole plate 6 is provided with a pinhole 6a (through hole) that penetrates the pinhole plate 6. The portion Lw passes through the pinhole 6a, thereby obtaining a laser light Lc. As shown in FIG. 2, the portion Lw is larger than the pinhole 6a.

[0028] Next, the light source unit 2 will be described in detail with reference to Fig. 3 to Fig. 5. Fig. 3 is a perspective view of the light source unit and the pinhole plate shown in Fig. 1. Fig. 4 is a plan view of the light source unit shown in Fig. 3. Fig. 5 is a front view of the light source unit shown in Fig. 3.

[0029] 3 to 5, the laser element 21 includes a laser body 21a, an electrode 21b, and a metal layer 21c. The laser body 21a has a rectangular parallelepiped shape extending in the front-rear direction. The laser body 21a has an exit port 21d (first exit port) that emits red light Lr. The exit port 21d is provided on the front end surface of the laser element 21. The exit port 21d is located near the center of the laser body 21a in the left-right direction and near the bottom end of the laser body 21a.

[0030] An electrode 21b is provided on the upper surface of the laser body 21a. The electrode 21b covers the upper surface of the laser body 21a. The electrode 21b is the upper electrode of the laser element 21. An example of a material for the electrode 21b is a gold-tin alloy (AuSn). In this embodiment, the electrode 21b functions as a cathode. A metal layer 21c is provided on the lower surface of the laser body 21a. The metal layer 21c covers the lower surface of the laser body 21a. The metal layer 21c is a solder layer for mounting the laser element 21. An example of a material for the metal layer 21c is SAC (SnAgCu).

[0031] The laser element 22 includes a laser body 22a, an electrode 22b, and a metal layer 22c. The laser body 22a has a rectangular parallelepiped shape extending in the front-rear direction. The laser body 22a has an exit 22d (second exit) that emits green light Lg. The exit 22d is provided on the front end surface of the laser element 22. The exit 22d is located near the right end of the laser body 22a in the left-right direction and near the lower end of the laser body 22a.

[0032] An electrode 22b is provided on the upper surface of the laser body 22a. The electrode 22b covers the upper surface of the laser body 22a. The electrode 22b is the upper electrode of the laser element 22. An example of a material for the electrode 22b is a gold-tin alloy (AuSn). In this embodiment, the electrode 22b functions as a cathode. A metal layer 22c is provided on the lower surface of the laser body 22a. The metal layer 22c covers the lower surface of the laser body 22a. The metal layer 22c is a solder layer for mounting the laser element 22. An example of a material for the metal layer 22c is SAC (SnAgCu).

[0033] The laser element 23 includes a laser body 23a, an electrode 23b, and a metal layer 23c. The laser body 23a has a rectangular parallelepiped shape extending in the front-rear direction. The laser body 23a has an exit 23d (third exit) that emits blue light Lb. The exit 23d is provided on the front end surface of the laser element 23. The exit 23d is located near the left end of the laser body 23a in the left-right direction and near the bottom end of the laser body 23a.

[0034] An electrode 23b is provided on the upper surface of the laser body 23a. The electrode 23b covers the upper surface of the laser body 23a. The electrode 23b is the upper electrode of the laser element 23. An example of a material for the electrode 23b is a gold-tin alloy (AuSn). In this embodiment, the electrode 23b functions as a cathode. A metal layer 23c is provided on the lower surface of the laser body 23a. The metal layer 23c covers the lower surface of the laser body 23a. The metal layer 23c is a solder layer for mounting the laser element 23. An example of a material for the metal layer 23c is SAC (SnAgCu).

[0035] The light source unit 2 further includes a substrate 24, a carrier 25, and a carrier 26. The substrate 24 is a base for mounting the laser element 21. In this embodiment, not only the laser element 21 but also the laser element 22 and the laser element 23 are mounted on the substrate 24. The substrate 24 functions as a carrier for the laser element 21. The substrate 24 includes a base material 41, a pad 42, a pad 43, and a pad 44.

[0036] The base material 41 is a member having a rectangular plate shape. Examples of materials for the base material 41 include silicon and aluminum nitride. The base material 41 has a mounting surface 41a and a back surface 41b. The mounting surface 41a is a surface on which the laser element 21 is mounted. The back surface 41b is a surface opposite to the mounting surface 41a in the thickness direction (vertical direction) of the base material 41.

[0037] The pads 42, 43, and 44 are provided on the mounting surface 41a. The pad 42 is a plate-shaped metal member for mounting the laser element 21. An example of a material for the pad 42 is a gold-tin alloy (AuSn). The outer shape of the pad 42 is larger than the outer shape of the laser element 21 in a plan view. In this embodiment, the pad 42 has a rectangular plate shape extending in the front-rear direction. The pad 42 is provided near the center in the left-right direction of the mounting surface 41a, and extends from the front end to near the rear end of the base material 41. The pad 42 also functions as a lower electrode of the laser element 21. In this embodiment, the pad 42 functions as an anode.

[0038] The pad 43 is a plate-shaped metal member for mounting the laser element 22. In this embodiment, the carrier 25 on which the laser element 22 is placed is mounted on the pad 43. An example of a material for the pad 43 is gold (Au). The outer shape of the pad 43 is larger than the outer shape of the carrier 25 in a plan view. In this embodiment, the pad 43 has a rectangular plate shape. The pad 43 is provided on the left side of the pad 42, and extends from near the center to near the rear end in the front-rear direction of the base material 41.

[0039] The pad 44 is a plate-shaped metal member for mounting the laser element 23. In this embodiment, the carrier 26 on which the laser element 23 is placed is mounted on the pad 44. An example of a material for the pad 44 is gold (Au). The outer shape of the pad 44 is larger than the outer shape of the carrier 26 in a plan view. In this embodiment, the pad 44 has a rectangular plate shape. The pad 44 is provided on the right side of the pad 42, and extends from a position rearward of the front end of the base material 41 to a position forward of the rear end.

[0040] The carrier 25 is a base for mounting the laser element 22. The carrier 25 is mounted on the mounting surface 41a. Specifically, the carrier 25 is mounted on the pad 43. The carrier 25 includes a base material 25a, a pad 25b, and a metal layer 25c. The base material 25a is a member having a rectangular plate shape. Examples of materials for the base material 25a include silicon and aluminum nitride. The outer shape of the base material 25a (carrier 25) is larger than the outer shape of the laser element 22 in a plan view.

[0041] A pad 25b is provided on the upper surface of the base material 25a. The pad 25b covers the upper surface of the base material 25a. The pad 25b is a plate-shaped metal member for mounting the laser element 22. An example of a material for the pad 25b is a gold-tin alloy (AuSn). The pad 25b also functions as a lower electrode of the laser element 22. In this embodiment, the pad 25b functions as an anode.

[0042] A metal layer 25c is provided on the lower surface of the base material 25a. The metal layer 25c covers the lower surface of the base material 25a. The metal layer 25c is a solder layer for mounting the carrier 25. An example of a material for the metal layer 25c is SAC (SnAgCu).

[0043] The carrier 26 is a base for mounting the laser element 23. The carrier 26 is mounted on the mounting surface 41a. Specifically, the carrier 26 is mounted on the pad 44. The carrier 26 includes a base material 26a, a pad 26b, and a metal layer 26c. The base material 26a is a member having a rectangular plate shape. Examples of materials for the base material 26a include silicon and aluminum nitride. The outer shape of the base material 26a (carrier 26) is larger than the outer shape of the laser element 23 in a plan view.

[0044] The pad 26b is provided on the upper surface of the base material 26a. The pad 26b covers the upper surface of the base material 26a. The pad 26b is a plate-shaped metal member for mounting the laser element 23. An example of a material for the pad 26b is a gold-tin alloy (AuSn). The pad 26b also functions as a lower electrode of the laser element 23. In this embodiment, the pad 26b functions as an anode.

[0045] A metal layer 26c is provided on the lower surface of the base material 26a. The metal layer 26c covers the lower surface of the base material 26a. The metal layer 26c is a solder layer for mounting the carrier 26. An example of a material for the metal layer 26c is SAC (SnAgCu).

[0046] The light source unit 2 further includes a wire Wr1, a wire Wr2, a wire Wg1, a wire Wg2, a wire Wb1, and a wire Wb2. The wires Wr1 and Wr2 are members for passing a driving current to the laser element 21. One end of the wire Wr1 is connected to the electrode 21b. One end of the wire Wr2 is connected to the pad 42.

[0047] The wire Wg1 and the wire Wg2 are members for passing a drive current to the laser element 22. One end of the wire Wg1 is connected to the electrode 22b. One end of the wire Wg2 is connected to the pad 25b. The wire Wb1 and the wire Wb2 are members for passing a drive current to the laser element 23. One end of the wire Wb1 is connected to the electrode 23b. One end of the wire Wb2 is connected to the pad 26b.

[0048] Next, the arrangement of the laser element 21, the laser element 22, and the laser element 23 will be described in detail with reference to Figs. 3 to 5. In this embodiment, the laser element 21, the laser element 22, and the laser element 23 have different radiation characteristics (horizontal beam divergence angle θh and vertical beam divergence angle θv). The laser element 21 has a beam divergence angle θh of 10° and a beam divergence angle θv of 32° under a condition of a light intensity of 5 mW, for example. The laser element 22 has a beam divergence angle θh of 7° and a beam divergence angle θv of 22° under a condition of a light intensity of 7 mW, for example. The laser element 23 has a beam divergence angle θh of 8° and a beam divergence angle θv of 23° under a condition of a light intensity of 7 mW, for example.

[0049] The beam divergence angle θh of the laser element 21 is larger than both the beam divergence angle θh of the laser element 22 and the beam divergence angle θh of the laser element 23. The beam divergence angle θv of the laser element 21 is larger than both the beam divergence angle θv of the laser element 22 and the beam divergence angle θv of the laser element 23. The larger the beam divergence angle of the laser element, the more likely the laser light emitted from that laser element is to diverge. Therefore, the laser element 21 is arranged so that the distance between the emission port 21d and the pinhole 6a is the shortest.

[0050] Specifically, the laser element 21 is disposed forward of both the laser element 22 and the laser element 23. In other words, the exit 21d is closer to the position (pinhole 6a) where the red light Lr, the green light Lg, and the blue light Lb overlap each other than both the exit 22d and the exit 23d. The vertical length of the substrate 24 (base material 41) is set so that the exit 21d is substantially at the same height as the center of the pinhole 6a. In the following description, the vertical length may be referred to as "thickness". The laser element 21 is disposed substantially parallel to the mounting surface 41a, and emits the red light Lr parallel to the mounting surface 41a. Therefore, the exit 21d is located in front of the pinhole 6a, and the central axis of the red light Lr (the emission direction of the red light Lr) coincides with the central axis of the pinhole 6a.

[0051] The beam divergence angle θh of the laser element 23 is slightly larger than the beam divergence angle θh of the laser element 22. The beam divergence angle θv of the laser element 23 is slightly larger than the beam divergence angle θv of the laser element 22. Therefore, the laser element 23 is disposed so that the distance between the exit 23d and the pinhole 6a is shorter than the distance between the exit 22d and the pinhole 6a.

[0052] Specifically, the laser element 23 is disposed behind the laser element 21 and in front of the laser element 22. In other words, the exit 23d is closer to the position (pinhole 6a) where the red light Lr, the green light Lg, and the blue light Lb overlap each other than the exit 22d. The laser element 23 is mounted on the mounting surface 41a via the carrier 26. Therefore, the exit 23d is located above the exit 21d by the thickness of the carrier 26. In other words, the distance Db from the mounting surface 41a to the exit 23d is greater than the distance Dr from the mounting surface 41a to the exit 21d.

[0053] The laser element 23 is disposed to the right of the laser element 21. The laser element 23 is provided on the carrier 26 at a position closer to the laser element 21 than the center of the carrier 26 in the left-right direction. The emission port 23d is located near the left end of the laser body 23a. In other words, the emission port 23d is provided at a position closer to the laser element 21 than the center of the carrier 26 in the left-right direction.

[0054] The orientation of the laser element 23 (exit port 23d) is set so that the blue light Lb emitted from the exit port 23d passes through the pinhole 6a. Specifically, the laser element 23 is inclined in the left-right direction so that the front end face of the laser element 23 is closer to the laser element 21 than the rear end face of the laser element 23. Therefore, the central axis of the blue light Lb (the emission direction of the blue light Lb) is inclined so as to approach the central axis of the red light Lr as it approaches the pinhole 6a.

[0055] 3, the laser element 23 is disposed substantially parallel to the mounting surface 41a and emits blue light Lb parallel to the mounting surface 41a. The laser element 23 may be inclined in the vertical direction so that the front end surface of the laser element 23 is closer to the mounting surface 41a than the rear end surface of the laser element 23.

[0056] The laser element 22 is disposed behind both the laser element 21 and the laser element 23. In other words, the exit 22d is farther from the position (pinhole 6a) where the red light Lr, the green light Lg, and the blue light Lb overlap each other than both the exit 21d and the exit 23d. The laser element 22 is mounted on the mounting surface 41a via the carrier 25. Therefore, the exit 22d is located above the exit 21d by the thickness of the carrier 25. Since the thickness of the carrier 25 is thicker than the thickness of the carrier 26, the exit 22d is located above the exit 23d. In other words, the distance Dg from the mounting surface 41a to the exit 22d is greater than both the distance Dr and the distance Db.

[0057] The laser element 22 is disposed to the left of the laser element 21. The laser element 22 is provided on the carrier 25 at a position closer to the laser element 21 than the center of the carrier 25 in the left-right direction. The emission port 22d is located near the right end of the laser body 22a. In other words, the emission port 22d is provided at a position closer to the laser element 21 than the center of the carrier 25 in the left-right direction.

[0058] The orientation of the laser element 22 (exit port 22d) is set so that the green light Lg emitted from the exit port 22d passes through the pinhole 6a. Specifically, the laser element 22 is inclined in the left-right direction so that the front end face of the laser element 22 is closer to the laser element 21 than the rear end face of the laser element 22. Therefore, the central axis of the green light Lg (the emission direction of the green light Lg) is inclined so as to approach the central axis of the red light Lr as it approaches the pinhole 6a.

[0059] 3, the laser element 22 is disposed substantially parallel to the mounting surface 41a and emits green light Lg parallel to the mounting surface 41a. The laser element 22 may be inclined in the up-down direction so that the front end surface of the laser element 22 is closer to the mounting surface 41a than the rear end surface of the laser element 22.

[0060] Next, a method for manufacturing the light source unit 2 will be described with reference to Fig. 6 to Fig. 9. Fig. 6 to Fig. 9 are diagrams for explaining the method for manufacturing the light source unit shown in Fig. 3.

[0061] First, the laser elements 21 to 23, the substrate 24, and the carriers 25 and 26 are prepared. Then, the laser element 22 is mounted on the carrier 25, whereby the laser element 22 and the carrier 25 are unitized to produce a unit 27 (see FIG. 7). Specifically, the laser element 22 is placed on the carrier 25 so that the metal layer 22c contacts the pad 25b. Then, the metal layer 22c is heated to melt the metal layer 22c, and then the metal layer 22c is solidified to bond the laser element 22 to the carrier 25.

[0062] Similarly, the laser element 23 is mounted on the carrier 26, whereby the laser element 23 and the carrier 26 are unitized to produce a unit 28 (see FIG. 8). Specifically, the laser element 23 is placed on the carrier 26 so that the metal layer 23c is in contact with the pad 26b. Then, the metal layer 23c is heated to melt the metal layer 23c, and then the metal layer 23c is solidified to bond the laser element 23 to the carrier 26.

[0063] 6, the laser element 21 is mounted on the substrate 24. Specifically, the laser element 21 is placed on the substrate 24 so that the metal layer 21c is in contact with the pad 42. The metal layer 21c is then heated to melt the metal layer 21c, and thereafter the metal layer 21c is solidified to bond the laser element 21 to the substrate 24.

[0064] 7, the laser element 22 is mounted on the substrate 24. Specifically, the unit 27 is placed on the substrate 24 so that the metal layer 25c is in contact with the pad 43. At this time, the unit 27 is placed in a state where the laser element 21 is emitting red light Lr and the laser element 22 is emitting green light Lg. Then, the direction and inclination of the unit 27 are adjusted by active alignment so that the red light Lr and the green light Lg overlap each other. Then, the metal layer 25c is heated to melt the metal layer 25c, and then the metal layer 25c is solidified to bond the unit 27 to the substrate 24.

[0065] 8, the laser element 23 is mounted on the substrate 24. Specifically, the unit 28 is placed on the substrate 24 so that the metal layer 26c is in contact with the pad 44. At this time, the unit 28 is placed in a state in which the laser element 21 emits red light Lr, the laser element 22 emits green light Lg, and the laser element 23 emits blue light Lb. Then, the direction and inclination of the unit 28 are adjusted by active alignment so that the red light Lr, the green light Lg, and the blue light Lb overlap each other. Then, the metal layer 26c is heated to melt the metal layer 26c, and then the metal layer 26c is solidified to bond the unit 28 to the substrate 24.

[0066] 9, wire bonding is performed. Specifically, one end of the wire Wr1 is connected to the electrode 21b, and one end of the wire Wr2 is connected to the pad 42. Similarly, one end of the wire Wg1 is connected to the electrode 22b, and one end of the wire Wg2 is connected to the pad 25b. Similarly, one end of the wire Wb1 is connected to the electrode 23b, and one end of the wire Wb2 is connected to the pad 26b.

[0067] The light source unit 2 is manufactured in this manner. The laser element 23 may be mounted on the substrate 24 before the laser element 22. The laser element 21 located at the front among the laser elements 21 to 23 is mounted first, and the laser element 22 and the laser element 23 are mounted so that the red light Lr is superimposed on the green light Lg and the blue light Lb. That is, the direction and inclination of the laser element 22 and the laser element 23 are adjusted so that the red light Lr, the green light Lg, and the blue light Lb are superimposed on each other, based on the red light Lr emitted along the central axis of the pinhole 6a. Since the laser element 22 and the laser element 23 are disposed behind the laser element 21, the possibility that the reference laser light (here, the red light Lr) is blocked by other laser elements or the like is reduced. Therefore, the mounting efficiency of the laser element 22 and the laser element 23 can be improved.

[0068] In the laser module 1 described above, the laser element 21, the laser element 22, and the laser element 23 are arranged so that the red light Lr, the green light Lg, and the blue light Lb overlap each other. Therefore, the red light Lr, the green light Lg, and the blue light Lb can be multiplexed without using optical components such as a dichroic mirror. As a result, a full-color laser module 1 can be realized and the laser module 1 can be made compact.

[0069] Since the laser element 21, the laser element 22, and the laser element 23 are arranged three-dimensionally, the distance Dr, the distance Dg, and the distance Db are different from each other. Specifically, the distance Db is greater than the distance Dr, and the distance Dg is greater than the distance Db. Therefore, even if the exit 22d is brought closer to the exit 21d, the possibility that the green light Lg is blocked by the laser element 21 is reduced. Therefore, compared to the case where the distance Dr and the distance Dg are the same, the exit 22d can be brought closer to the exit 21d. Similarly, even if the exit 23d is brought closer to the exit 21d, the possibility that the blue light Lb is blocked by the laser element 21 is reduced. Therefore, compared to the case where the distance Dr and the distance Db are the same, the exit 23d can be brought closer to the exit 21d.

[0070] From the above, the emission direction of the red light Lr, the emission direction of the green light Lg, and the emission direction of the blue light Lb can be made closer to each other. In other words, the angle between any two of the emission directions of the red light Lr, the emission direction of the green light Lg, and the emission direction of the blue light Lb can be made smaller. This makes it possible to suppress the degree to which the red light Lr, the green light Lg, and the blue light Lb diverge downstream in the emission direction from the position where the red light Lr, the green light Lg, and the blue light Lb overlap each other.

[0071] The laser element 22 is placed on a carrier 25, and the laser element 23 is placed on a carrier 26. The carriers 25 and 26 are placed on a mounting surface 41a. Therefore, the distance Dg varies according to the thickness of the carrier 25, and the distance Db varies according to the thickness of the carrier 26. In other words, the distance Dg can be changed simply by changing the thickness of the carrier 25, and the distance Db can be changed simply by changing the thickness of the carrier 26. Therefore, it is possible to easily adjust the distances Dg and Db.

[0072] Since the distances Dr, Dg, and Db are different from one another, when the red light Lr, the green light Lg, and the blue light Lb are emitted parallel to the mounting surface 41a, the portion Lw may be narrowed. On the other hand, when the laser element 22 is arranged so that the emission direction of the green light Lg is inclined with respect to the mounting surface 41a, the portion where the red light Lr and the green light Lg overlap with each other can be widened, and the portion Lw can be widened. Similarly, when the laser element 23 is arranged so that the emission direction of the blue light Lb is inclined with respect to the mounting surface 41a, the portion where the red light Lr and the blue light Lb overlap with each other can be widened, and the portion Lw can be widened.

[0073] The beam divergence angle θh of the laser element 21 is larger than both the beam divergence angle θh of the laser element 22 and the beam divergence angle θh of the laser element 23. The beam divergence angle θv of the laser element 21 is larger than both the beam divergence angle θv of the laser element 22 and the beam divergence angle θv of the laser element 23. The larger the beam divergence angle of the laser element, the easier it is for the laser light emitted from the laser element to diverge. Therefore, since the red light Lr is easier to diverge than both the green light Lg and the blue light Lb, by placing the exit 21d closer to the position (pinhole 6a) where the red light Lr, the green light Lg, and the blue light Lb overlap each other than both the exit 22d and the exit 23d, the degree of divergence of the laser light as a whole at the above position can be suppressed.

[0074] The exit 22d is provided at a position closer to the laser element 21 than the center in the left-right direction of the carrier 25. Therefore, the exit 22d approaches the exit 21d, so that the angle between the emission direction of the red light Lr and the emission direction of the green light Lg can be reduced. Similarly, the exit 23d is provided at a position closer to the laser element 21 than the center in the left-right direction of the carrier 26. Therefore, the exit 23d approaches the exit 21d, so that the angle between the emission direction of the red light Lr and the emission direction of the blue light Lb can be reduced. As a result, it is possible to suppress the degree to which the red light Lr, the green light Lg, and the blue light Lb diverge downstream in the emission direction from the position where the red light Lr, the green light Lg, and the blue light Lb overlap each other.

[0075] Laser light Lc is obtained by passing part Lw through the pinhole 6a, and red light Lr, green light Lg, and blue light Lb that are not included in part Lw are blocked by the pinhole plate 6. This makes it possible to remove stray light.

[0076] Since each of the laser elements 21 to 23 is an edge-emitting type laser element, each laser element emits laser light from both the front and rear end faces. The photodetector 3 is disposed on the opposite side of the laser element 21 to the emission direction of the red light Lr, and receives the laser light emitted from the rear end face of the laser element 21. In the laser element 21, the ratio between the light intensity of the red light Lr emitted from the front end face and the light intensity of the laser light emitted from the rear end face is preset. Therefore, the light intensity of the red light Lr can be monitored without using any optical components for splitting the red light Lr.

[0077] Similarly, the photodetector 4 is disposed on the opposite side of the laser element 22 to the emission direction of the green light Lg, and receives the laser light emitted from the rear end face of the laser element 22. In the laser element 22, the ratio between the light intensity of the green light Lg emitted from the front end face and the light intensity of the laser light emitted from the rear end face is preset. Therefore, the light intensity of the green light Lg can be monitored without using any optical components for splitting the green light Lg.

[0078] Similarly, the photodetector 5 is disposed on the opposite side of the laser element 23 to the emission direction of the blue light Lb, and receives the laser light emitted from the rear end face of the laser element 23. In the laser element 23, the ratio between the light intensity of the blue light Lb emitted from the front end face and the light intensity of the laser light emitted from the rear end face is preset. Therefore, the light intensity of the blue light Lb can be monitored without using any optical components for splitting the blue light Lb. From the above, it is possible to further miniaturize the laser module 1.

[0079] The laser module according to the present disclosure is not limited to the above embodiment.

[0080] For example, the laser module 1 is not limited to a configuration in which red light Lr, green light Lg, and blue light Lb are multiplexed, and may be a configuration in which at least two laser beams are multiplexed. In this case, the laser elements that emit the respective laser beams are arranged so that the at least two laser beams overlap each other.

[0081] The light source unit 2 may further include a carrier on which the laser element 21 is placed. This carrier may be placed on the placement surface 41a. The light source unit 2 may not include at least one of the carrier 25 and the carrier 26. The emission port 21d, the emission port 22d, and the emission port 23d may be located on the same plane parallel to the placement surface 41a. In other words, the distance Dr, the distance Dg, and the distance Db may be the same as each other.

[0082] The carrier 25 may not be placed on the mounting surface 41a. The carrier 26 may not be placed on the mounting surface 41a. In other words, the laser element 21, the laser element 22, and the laser element 23 may not be provided on the same substrate 24, and may be provided on individual carriers.

[0083] Instead of the exit 21d, the exit 22d may be located in front of the pinhole 6a, and the central axis of the green light Lg (the emission direction of the green light Lg) may coincide with the central axis of the pinhole 6a. In this case, the laser element 21, the laser element 22, and the laser element 23 may be arranged in that order in the left-right direction. Alternatively, the exit 23d may be located in front of the pinhole 6a, and the central axis of the blue light Lb (the emission direction of the blue light Lb) may coincide with the central axis of the pinhole 6a. In this case, the laser element 21, the laser element 23, and the laser element 22 may be arranged in that order in the left-right direction.

[0084] The laser module 1 may further include a collimator lens that converts the laser light Lc into parallel light.

[0085] The laser element 21 may be disposed so that the emission direction of the red light Lr is inclined with respect to the mounting surface 41a. The laser element 22 may be disposed so that the emission direction of the green light Lg is inclined with respect to the mounting surface 41a. The laser element 23 may be disposed so that the emission direction of the blue light Lb is inclined with respect to the mounting surface 41a.

[0086] As shown in FIG. 10, the laser module 1 may further include a metal body 50. In the example shown in FIG. 10, the metal body 50 is used to bond the laser element 22 and the carrier 25 (pad 25b). The metal body 50 includes a metal ball 51 and a plating layer 52. The metal ball 51 has rigidity. An example of a material of the metal ball 51 is copper. The plating layer 52 is provided on the surface of the metal ball 51. The plating layer 52 covers the entire surface of the metal ball 51. When the metal body 50 is heated, the plating layer 52 melts, and then the plating layer 52 solidifies, thereby bonding the laser element 22 to the carrier 25 via the metal body 50.

[0087] The metal body 50 may be a GGI (Gold to Gold Interconnect). In this case, the metal body 50 includes a metal ball 51 having rigidity. An example of a material of the metal ball 51 is gold (Au). The metal body 50 is joined by friction caused by ultrasonic vibration.

[0088] The metal ball 51 has rigidity and is therefore not easily deformed. Therefore, the inclination and distance Dg of the laser element 22 are determined by the metal ball 51. This makes it possible to easily adjust the inclination and distance Dg of the laser element 22. Instead of adjusting the inclination by the metal body 50, the carrier 25 itself may be tilted.

[0089] The metal body 50 may be used to join the laser element 21 and the mounting surface 41a (pad 42), or may be used to join the laser element 23 and the carrier 26 (pad 26b). The metal body 50 may be used to join the carrier 25 and the mounting surface 41a (pad 43), or may be used to join the carrier 26 and the mounting surface 41a (pad 44).

[0090] (Additional Note) [Clause 1] a first laser element having a first emission port for emitting a first laser beam; a second laser element having a second emission port for emitting a second laser beam; Equipped with the first laser element and the second laser element are arranged such that the first laser light and the second laser light overlap each other.

[0091] [Clause 2] a substrate having a mounting surface on which the first laser element is mounted; Item 2. The laser module described in item 1, wherein a distance from the mounting surface to the first emission port is different from a distance from the mounting surface to the second emission port.

[0092] [Clause 3] a carrier on which the second laser element is mounted; 3. The laser module of claim 2, wherein the carrier is placed on the mounting surface.

[0093] [Article 4] the first exit port is closer to a position where the first laser light and the second laser light overlap each other than the second exit port; The laser module described in clause 3, wherein the second emission port is provided at a position closer to the first laser element than a center of the carrier in an arrangement direction of the first laser element and the second laser element.

[0094] [Article 5] a metal body that bonds the second laser element and the carrier; 5. The laser module of claim 3 or 4, wherein the metal body comprises a rigid metal sphere.

[0095] [Article 6] The laser module according to any one of clauses 2 to 5, wherein the second laser element is disposed so that an emission direction of the second laser light is inclined with respect to the placement surface.

[0096] [Article 7] a beam divergence angle of the first laser element is larger than a beam divergence angle of the second laser element; 7. The laser module according to any one of clauses 1 to 6, wherein the first exit port is closer to a position where the first laser light and the second laser light overlap each other than the second exit port.

[0097] [Article 8] The laser module according to any one of clauses 1 to 7, further comprising an extraction member having a through hole through which the first laser light and the second laser light pass at a portion where they overlap with each other.

[0098] [Article 9] a first photodetector for monitoring the light intensity of the first laser light; a second photodetector for monitoring the light intensity of the second laser light; Further comprising: each of the first laser element and the second laser element is an edge-emitting laser element; the first photodetector is disposed on an opposite side to an emission direction of the first laser light with respect to the first laser element, The laser module according to any one of clauses 1 to 8, wherein the second photodetector is disposed on an opposite side to an emission direction of the second laser light with respect to the second laser element.

[0099] [Article 10] a third laser element having a third emission port for emitting a third laser light, the first laser light is red light, the second laser light is green light, Item 10. The laser module according to any one of items 1 to 9, wherein the third laser light is blue light. [Explanation of symbols]

[0100] 1...laser module, 2...light source unit, 3...photodetector (first photodetector), 4...photodetector (second photodetector), 6...pinhole plate (extraction member), 6a...pinhole (through hole), 21...laser element (first laser element), 21d...output port (first output port), 22...laser element (second laser element), 22d...output port (second output port), 23...laser element (third laser element), 23d...output port (third output port), 24...substrate, 25...carrier, 41a...mounting surface, 50...metal body, 51...metal ball.

Claims

1. a first laser element having a first emission port for emitting a first laser beam; a second laser element having a second emission port for emitting a second laser beam; Equipped with The first laser element and the second laser element are arranged so that the first laser light and the second laser light overlap each other.

2. a substrate having a mounting surface on which the first laser element is mounted; The laser module according to claim 1 , wherein a distance from the mounting surface to the first emission opening is different from a distance from the mounting surface to the second emission opening.

3. a carrier on which the second laser element is mounted; The laser module according to claim 2 , wherein the carrier is placed on the placement surface.

4. the first exit port is closer to a position where the first laser light and the second laser light overlap each other than the second exit port; The laser module according to claim 3 , wherein the second emission aperture is provided at a position closer to the first laser element than a center of the carrier in an arrangement direction of the first laser element and the second laser element.

5. a metal body that bonds the second laser element and the carrier; The laser module according to claim 3 or 4, wherein the metal body comprises a rigid metal ball.

6. 5. The laser module according to claim 2, wherein the second laser element is disposed such that an emission direction of the second laser light is inclined with respect to the placement surface.

7. a beam divergence angle of the first laser element is larger than a beam divergence angle of the second laser element; 5. The laser module according to claim 1, wherein the first exit port is closer to a position where the first laser light and the second laser light overlap each other than the second exit port.

8. The laser module according to any one of claims 1 to 4, further comprising an extraction member having a through hole through which the first laser light and the second laser light pass at an overlapping portion.

9. a first photodetector for monitoring the light intensity of the first laser light; a second photodetector for monitoring the light intensity of the second laser light; Further comprising: Each of the first laser element and the second laser element is an edge-emitting laser element, the first photodetector is disposed on an opposite side to an emission direction of the first laser light with respect to the first laser element, 5. The laser module according to claim 1, wherein the second photodetector is disposed on an opposite side to an emission direction of the second laser light with respect to the second laser element.

10. a third laser element having a third emission port for emitting a third laser light, the first laser light is red light, the second laser light is green light, 5. The laser module according to claim 1, wherein the third laser light is blue light.

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