Semiconductor laser bar unit, layered structure, and method for manufacturing semiconductor laser bar unit

Abstract

A semiconductor laser bar unit 4 includes: a semiconductor laser bar 11 that has an emission end surface 15 extending in a long direction D1 and a short direction D2, and has a plurality of laser emission points 16 arranged along the long direction D1 of the emission end surface 15; a long lens 31 that is present extending along the long direction D1 so as to face the plurality of laser emission points 16; and a positioning member 41 that positions the lens 31 relative to the emission end surface 15, wherein the positioning member 41 is positioned in a non-arrangement region R2 excluding an arrangement region R1 for the plurality of laser emission points 16 on the emission end surface 15, and is joined to the emission end surface 15 and the lens 31 in the non-arrangement region R2.

Description

Semiconductor Laser Bar Unit, Stacked Structure, and Method for Manufacturing Semiconductor Laser Bar Unit

[0001] The present disclosure relates to a semiconductor laser bar unit, a stacked structure, and a method for manufacturing a semiconductor laser bar unit.

[0002] As a conventional semiconductor laser bar unit, for example, there is a semiconductor laser device described in Patent Document 1. In this semiconductor laser device, a semiconductor laser bar array in which a plurality of semiconductor laser bars having a plurality of laser emission points arranged in the longitudinal direction of the emission end face are arranged side by side, a housing that houses the semiconductor laser bar array, and a condenser lens that extends along the longitudinal direction of the emission end face so as to face the emission end face of the semiconductor laser bar, and a pair of lens holders that protrude from the front surface of the housing and support both ends of the collimating lens.

[0003] Japanese Patent Application Laid-Open No. 2002-305346

[0004] In recent years, with the demand for higher integration of semiconductor laser bars, semiconductor laser bars have been on the path of miniaturization. As the size of the semiconductor laser bar is miniaturized, the size of the emission end face becomes smaller, and the arrangement pitch of the semiconductor laser bars also becomes narrower. Since the lens disposed with respect to the emission end face is also miniaturized, it has become an issue to easily ensure the positioning accuracy when mounting the lens with respect to the semiconductor laser bar.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a semiconductor laser bar unit, a stacked structure, and a method for manufacturing a semiconductor laser bar unit that can easily ensure the positioning accuracy of a lens with respect to the emission end face of a miniaturized semiconductor laser bar.

[0006] The gist of the present disclosure is as follows.

[0007] [1] A semiconductor laser bar unit comprising: a semiconductor laser bar having an exit end face extending in a longitudinal direction and a transverse direction, wherein a plurality of laser emission points are arranged along the longitudinal direction of the exit end face; an elongated lens extending along the longitudinal direction so as to face the plurality of laser emission points; and a positioning member for positioning the lens with respect to the exit end face, wherein the positioning member is arranged in a non-arranged region of the exit end face excluding the area where the plurality of laser emission points are arranged, and is joined to the exit end face and the lens in the non-arranged region.

[0008] In this semiconductor laser bar unit, a positioning member for positioning the lens relative to the output end face is provided on the output end face. Because the positioning member is directly provided on the output end face, accurate positioning of the lens relative to the output end face can be easily ensured even when the size of the output end face and lens is small. Since the positioning member is located in a non-arranged region excluding the area where multiple laser output points are arranged, the effect of heat from light emission at the laser output points on the positioning member and the stress from installing the positioning member on the area where the laser output points are arranged can be suppressed.

[0009] [2] The semiconductor laser bar unit according to [1], wherein the positioning members are arranged in at least two locations in the non-arranged region. In this case, the positioning members can support the lens at two or more points, making it easier to position the lens relative to the output end face.

[0010] [3] The semiconductor laser bar unit according to [1] or [2], wherein the positioning member is positioned at a location offset in the longitudinal direction with respect to the plurality of laser emission points. In this case, the effect of heat due to light emission at the laser emission points on the positioning member and the stress when providing the positioning member on the arrangement region of the laser emission points can be suppressed even more reliably. Furthermore, the obstruction of light emitted from the laser emission points by the positioning member can also be suppressed.

[0011] [4] The semiconductor laser bar unit according to any one of [1] to [3], wherein the positioning member is positioned at a location offset in the shorter direction relative to the plurality of laser emission points. In this case, the effect of heat due to light emission at the laser emission points on the positioning member and the stress when providing the positioning member on the arrangement region of the laser emission points can be suppressed even more reliably. Furthermore, the obstruction of light emitted from the laser emission points by the positioning member can also be suppressed.

[0012] [5] The semiconductor laser bar unit according to any one of [1] to [4], wherein the positioning members are arranged at both ends in the longitudinal direction of the emission end face. In this case, the effect of heat due to light emission at the laser emission point on the positioning members and the stress when providing the positioning members on the arrangement region of the laser emission points can be suppressed even more reliably. In addition, it can be suppressed that the light emitted from the laser emission point is blocked by the positioning members.

[0013] [6] The semiconductor laser bar unit according to any one of [1] to [5], wherein the positioning member overlaps with the lens when viewed from the direction opposite to the exit end face and the lens, and one side of the positioning member extending in the longitudinal direction coincides with one side of the lens extending in the longitudinal direction at a distance from the laser emission point that is half the dimension of the lens in the short direction. In this case, the center of the lens in the short direction relative to the laser emission point can be easily aligned simply by aligning one side of the lens extending in the longitudinal direction with one side of the positioning member extending in the longitudinal direction.

[0014] [7] The semiconductor laser bar unit according to any one of [1] to [6], wherein the positioning member overlaps with the lens when viewed from the direction opposite to the exit end face and the lens, and one side of the positioning member extending in the short direction coincides with one side of the lens extending in the short direction. In this case, the lens can be easily positioned relative to the exit end face simply by aligning one side of the lens extending in the short direction with one side of the positioning member extending in the short direction.

[0015] [8] The semiconductor laser bar unit according to any one of [1] to [7], wherein the protrusion length of the positioning member from the output end face matches the back focus of the lens. In this case, the positioning member functions as a spacer to match the back focus of the lens to the output end face, and the back focus of the lens can be accurately aligned to the output end face based on the protrusion length of the positioning member.

[0016] A laminated structure having a plurality of unit structures to which any of the semiconductor laser bar units described in [9], [1], to [8] are joined to a submount, wherein the plurality of unit structures are joined to each other in a stacked state in the short direction.

[0017] In this laminated structure, a positioning member for positioning the lens relative to the output end face is provided on the output end face of each semiconductor laser bar unit. Because the positioning member is directly provided on the output end face, accurate positioning of the lens relative to the output end face can be easily ensured even when the size of the output end face and the lens is small. By stacking multiple unit structures including such semiconductor laser bar units in the short-side direction, a laminated structure in which the lens is accurately positioned relative to the output end face of each semiconductor laser bar unit can be easily obtained.

[0018]

[10] A method for manufacturing a semiconductor laser bar unit, comprising: a first preparation step of preparing a semiconductor laser bar having an exit end face extending in a longitudinal direction and a transverse direction, wherein a plurality of laser emission points are arranged along the longitudinal direction of the exit end face; a second preparation step of preparing a long lens that can extend along the longitudinal direction of the exit end face; a forming step of forming a positioning member for positioning the lens relative to the exit end face in a non-arranged region of the exit end face excluding the area where the plurality of laser emission points are arranged; a positioning step of positioning the lens relative to the exit end face using the positioning member as an alignment mark so that the lens faces the plurality of laser emission points; and a bonding step of bonding the lens to the exit end face via the positioning member.

[0019] In this semiconductor laser bar unit manufacturing method, a positioning member for positioning the lens relative to the output end face is provided on the output end face. By directly providing the positioning member on the output end face, the positioning accuracy of the lens relative to the output end face can be easily ensured even when the size of the output end face and lens is small. By placing the positioning member in a non-arranged region excluding the area where multiple laser output points are arranged, the effect of heat from light emission at the laser output points on the positioning member and the stress when providing the positioning member on the area where the laser output points are arranged can be suppressed.

[0020]

[11] The method for manufacturing a semiconductor laser bar unit according to

[10] , wherein the positioning member is formed using a three-dimensional printing technique by micro-nano photopolymerization in the forming step. In this case, by using a three-dimensional printing technique by micro-nano photopolymerization, a fine positioning member can be formed with high precision.

[0021]

[12] A method for manufacturing a semiconductor laser bar unit according to

[10] or

[11] , wherein in the forming step, a first portion of the positioning member is formed on the exit end face and a second portion of the positioning member is formed on the lens, and in the positioning step, the lens is positioned relative to the exit end face by abutting the first portion and the second portion. In this case, the thickness of the positioning member formed on the exit end face can be reduced, so that the stress when providing the positioning member does not extend to the arrangement region of the laser emission points can be effectively suppressed.

[0022] According to this disclosure, the positioning accuracy of the lens relative to the output end face of a miniaturized semiconductor laser bar can be easily ensured.

[0023] This is a schematic cross-sectional view showing the configuration of a semiconductor laser device including a stacked structure according to one embodiment of the present disclosure. This is a front view showing the configuration of the exit end face and lens. This is a side view showing the configuration of the exit end face and lens. This is a flowchart showing a method for manufacturing a semiconductor laser bar unit according to one embodiment of the present disclosure. This is a front view showing the exit end face in the forming step. This is a front view showing the exit end face and lens in the positioning step. This is a side view showing the forming step according to a modified example. This is a front view showing the configuration of the exit end face and lens according to a modified example. This is a side view showing the configuration of the exit end face and lens according to a modified example.

[0024] Hereinafter, with reference to the drawings, preferred embodiments of a semiconductor laser bar unit, a laminated structure, and a method for manufacturing a semiconductor laser bar unit relating to one aspect of this disclosure will be described in detail.

[0025] Figure 1 is a schematic cross-sectional view showing the configuration of a semiconductor laser device including a laminated structure according to one embodiment of the present disclosure. As shown in Figure 1, the semiconductor laser device 1 comprises a heat sink 2, a laminated structure 3 formed by stacking a plurality of semiconductor laser bar units 4, and a pair of electrodes 5, 5. The semiconductor laser bar unit 4 comprises a semiconductor laser bar 11, a lens 31 and a positioning member 41, which will be described later. The laminated structure 3 is formed by stacking a plurality of unit structures K, each formed by joining a semiconductor laser bar unit 4 to a submount 12, in the stacking direction X.

[0026] The semiconductor laser device 1 has a rear cooling structure in which cooling is performed on the opposite side of the direction of laser light oscillation. With this cooling structure, the heat generated in the semiconductor laser bar 11 during laser oscillation is dissipated to the heat sink 2 via a submount 12 or the like. In this embodiment, the heat sink 2 is formed in the shape of a thick plate made of a material with excellent heat conductivity.

[0027] The heat sink 2 can be formed from materials such as copper, CuW (copper-tungsten), or copper-diamond composite materials. The surface layer on the mounting surface M side of the heat sink 2 may be formed from copper, CuW, or copper-diamond composite material, while other parts may be formed from Kovar or 42 alloy (an alloy of iron with 42% nickel) which have a similar coefficient of thermal expansion to copper, CuW, or copper-diamond composite material. One surface of the heat sink 2 is a flat surface and serves as the mounting surface M on which the laminated structure 3 is mounted. A channel for a cooling medium such as water may be formed inside the heat sink 2.

[0028] The semiconductor laser bar 11 is an element that emits laser light. The semiconductor laser bar 11 and the submount 12 are electrically and thermally connected to each other. The semiconductor laser bar 11 is, for example, plate-shaped. The leading edge 11a of the semiconductor laser bar 11 is an emission end surface 15 having a plurality of laser emission points 16 (see Figure 2). In the example in Figure 1, the plurality of laser emission points 16 on the emission end surface 15 are arranged at predetermined intervals in the depth direction of the paper.

[0029] The semiconductor laser bar 11 has a substrate made of, for example, a compound semiconductor. On the substrate, an active layer is located at positions corresponding to a plurality of laser emission points 16, and cladding layers are located on both sides of the active layer. Examples of substrate materials include gallium arsenide (GaAs), gallium nitride (GaN), aluminum gallium arsenide (AlGaAs), (gallium phosphide)GaP, aluminum gallium nitride (AlGaN), and indium phosphide (InP). In this embodiment, the main component of the substrate is gallium arsenide (GaAs), the active layer further contains indium (In), and the cladding layer further contains aluminum (Al).

[0030] The submount 12 is formed in a plate shape from a material having thermal and electrical conductivity. Examples of materials for forming the submount 12 include copper tungsten (CuW), aluminum nitride (AlN), silicon carbide (SiC), tungsten (W), copper molybdenum (MoCu) composite material, and copper diamond composite material. In this embodiment, the submount 12 is formed from copper tungsten (CuW). The surface of the submount 12 may have two plating layers formed on it, for example, nickel (Ni) and gold (Au).

[0031] In the laminated structure 3, multiple semiconductor laser bar units 4 are stacked such that submounts 12 and semiconductor laser bars 11 are arranged alternately. An additional submount 12 is stacked on one end of the stacked semiconductor laser bar unit 4 of the laminated structure 3. The laminated structure 3 is positioned relative to the mounting surface M of the heat sink 2 such that the stacking direction X of the semiconductor laser bar units 4 coincides with the in-plane direction of the mounting surface M of the heat sink 2.

[0032] As an example, the width of the semiconductor laser bar 11 in the stacking direction X is approximately 100 μm to 150 μm. Also, the width of the submount 12 in the stacking direction X is approximately 100 μm to 500 μm. The arrangement pitch of the semiconductor laser bar 11 in the stacked structure 3 is the distance between adjacent semiconductor laser bar 11 in the stacking direction X, and is approximately 100 μm to 500 μm depending on the thickness of the submount 12 in the stacking direction X.

[0033] A solder layer (not shown) may be used to join the submount 12 and the semiconductor laser bar 11. Examples of materials for this solder layer include gold-tin (AuSn) solder. This solder layer may be provided on the surface of the submount 12 by methods such as vapor deposition or sheet bonding. The solder layer may also be provided so as to cover the entire surface of the submount 12.

[0034] The end face 12a of the submount 12 opposite to the heatsink 2 is flush with the output end face 15 of the semiconductor laser bar 11. Also, the end face 12b of the submount 12 on the heatsink 2 side protrudes toward the heatsink 2 side more than the end face 11b of the semiconductor laser bar 11 on the heatsink 2 side. The laminated structure 3 is fixed to the heatsink 2 by joining each of the submounts 12 to the mounting surface M, with each of the semiconductor laser bars 11 spaced apart from the mounting surface M.

[0035] In the example shown in Figure 1, a solder layer 21 and an insulating member 23 are used to join the submount 12 and the heat sink 2. Examples of materials for the solder layer 21 include indium (In)-based solder and SnAgCu-based solder. Examples of methods for forming the solder layer 21 include vapor deposition or sheet bonding. The solder layer 21 extends across the mounting surface M so as to span each of the submounts 12. The solder layer 21 is provided over substantially the entire surface of the mounting surface M of the heat sink 2, excluding the edges, so as to correspond to the entire arrangement area of ​​the laminated structure 3 when viewed from the direction normal to the mounting surface M. As a result, all submounts 12 from one end to the other in the stacking direction X of the laminated structure 3 are joined to the heat sink 2 collectively by a single solder layer 21 on the mounting surface M.

[0036] The insulating member 23 is a heat-conducting and electrically insulating member interposed between the laminated structure 3 and the heat sink 2. Examples of constituent materials for the insulating member 23 include aluminum nitride (AlN), silicon carbide (SiC), and diamond. In this embodiment, the insulating member 23 is formed of aluminum nitride (AlN). The insulating member 23 is in the form of a sheet having the same planar shape as, for example, the end face 12c of the submount 12 on the heat sink 2 side. The insulating member 23 is provided individually on each of the submounts 12. The shapes of the insulating members 23 provided individually on each of the submounts 12 are identical to each other.

[0037] The pair of electrodes 5 are components that apply a driving voltage from a power source (not shown) to each semiconductor laser bar 11 contained in the laminated structure 3. In this embodiment, each of the pair of electrodes 5 is formed in the form of a thin film and is electrically connected to a submount 12 located at one end of the laminated structure 3 and to a submount 12 located at the other end of the laminated structure 3, respectively. As the material for forming the electrodes 5, copper (Cu) or the like can be used, considering the ease of thin film processing.

[0038] In the semiconductor laser apparatus 1 described above, each semiconductor laser bar 11 contained in the stacked structure 3 has a long lens 31 positioned opposite a plurality of laser emission points 16. The lens 31 focuses or aligns the laser light emitted from the plurality of laser emission points 16. Here, the lens 31 is a uniconvex microlens, with one surface being convex and the other flat. In a front view, the shape of the lens 31 is rectangular, corresponding to the shape of the emission end face 15. The configuration of the semiconductor laser bar 11 and the lens 31 will be described in detail below.

[0039] Figure 2 is a front view showing the configuration of the output end face and lens. Figure 3 is a side view thereof. First, the configuration of the output end face 15 of the semiconductor laser bar 11, to which the lens 31 is attached, will be explained. As shown in Figure 2, the output end face 15 is rectangular in shape when viewed from the front and extends in the longitudinal direction D1 and the short direction D2. The longitudinal direction D1 is the direction in which a pair of long sides 15a and 15b of the output end face 15 extend when viewed from the front, and corresponds to the depth direction of the paper in Figure 1. The short direction D2 is the direction in which a pair of short sides 15c and 15d of the output end face 15 extend when viewed from the front, and corresponds to the left-right direction of the paper in Figure 1. The short direction D2 coincides with the stacking direction X of the multiple unit structures K that constitute the stacked structure 3. That is, in the stacked structure 3, the multiple unit structures K are joined to each other in a state where they are stacked in the short direction D2.

[0040] The output end face 15 has an array region R1 of multiple laser output points 16 and a non-arranged region R2 excluding the array region R1. In this embodiment, the array region R1 is the region where the active layer of the substrate constituting the semiconductor laser bar 11 is located. The multiple laser output points 16 are arranged in the longitudinal direction D1 at predetermined intervals within the array region R1. The non-arranged region R2 is the region where the cladding layer and the like are located, excluding the active layer. In the examples of Figures 2 and 3, the array region R1 is offset from the center of the short direction D2 towards one of the longer sides 15b and extends along the longitudinal direction D1 connecting the short sides 15c and 15d.

[0041] A positioning member 41 is used to attach the lens 31 to the exit end face 15. The positioning member 41 is formed into a flat rectangular parallelepiped shape using, for example, a three-dimensional printing technology using micro-nano photopolymerization. In a front view of the exit end face 15, the positioning member 41 has a rectangular shape. Examples of three-dimensional printing technologies using micro-nano photopolymerization include the two-photon polymerization (TPP: Two-photon polymerization based direct laser writing) method, which uses an ultrashort pulse laser to harden a photosensitive material located in the focal region, or the projection micro-stereo lithography (PμSL: Projection Micro-Stereo Lithography) method, which exposes the entire surface of a dynamic mask with ultraviolet light to harden the photosensitive material.

[0042] The positioning member 41 is positioned in the non-arranged region R2 of the output end face 15, excluding the arrangement region R1 of the multiple laser output points 16. The positioning member 41 may be positioned in at least two locations in the non-arranged region R2. The positioning member 41 may be positioned offset in the longitudinal direction D1 or offset in the short direction D2 with respect to the multiple laser output points 16. An offset in the longitudinal direction D1 means, for example, that no laser output points 16 are located in the short direction D2 with respect to the positioning member 41 (the positioning member 41 is not located in the region extending from the laser output points 16 in the short direction D2). An offset in the short direction D2 means, for example, that no laser output points 16 are located in the longitudinal direction D1 with respect to the positioning member 41 (the positioning member 41 is not located in the region extending from the laser output points 16 in the longitudinal direction D1).

[0043] In this embodiment, as shown in Figure 2, the positioning members 41 are arranged at both ends 15e and 15f in the longitudinal direction of the exit end face 15. The positioning members 41 on both end faces 15e are positioned at the corner 15g formed by the long side 15a and the short side 15c, such that one side 41a extending in the longitudinal direction D1 (hereinafter referred to as "long side") 41a is along the long side 15a of the exit end face 15, and one side 41b extending in the short direction D2 (hereinafter referred to as "short side") 41b is along the short side 15c of the exit end face 15. The long side 41a of the positioning member 41 and the long side 15a of the exit end face 15 may coincide, or they may be spaced apart at a predetermined interval in the short direction D2. The short side 41b of the positioning member 41 and the short side 15c of the exit end face 15 may coincide, or they may be spaced apart at a predetermined interval in the longitudinal direction D1.

[0044] Similarly, the positioning members 41 on both end portions 15f are positioned at the corner portion 15h formed by the long side 15a and the short side 15d of the ejection end surface 15, such that the long side 41a is aligned with the long side 15a of the ejection end surface 15 and the short side 41b is aligned with the short side 15d of the ejection end surface 15. The long side 41a of the positioning member 41 and the long side 15a of the ejection end surface 15 may coincide, or they may be spaced apart at a predetermined interval in the short direction D2. The short side 41b of the positioning member 41 and the short side 15c of the ejection end surface 15 may coincide, or they may be spaced apart at a predetermined interval in the longitudinal direction D1.

[0045] For the joining of the lens 31 and the positioning member 41, for example, an adhesive is used. As the adhesive, for example, a UV curable resin or the like can be used. The lens 31 in the joined state has a rectangular shape in a front view of the emission end face 15. In a front view of the emission end face 15, the lens 31 has one side (hereinafter referred to as "long side") 31a extending in the longitudinal direction D1 and one side (hereinafter referred to as "short side") 31b extending in the short side direction D2.

[0046] As shown in FIG. 2, the positioning member 41 in the joined state overlaps the lens 31 when viewed from the direction facing the emission end face 15 and the lens 31. Also, when viewed from the direction facing the emission end face 15 and the lens 31, the corners of the positioning member 41 and the lens 31 coincide with each other. That is, the long side 41a of the positioning member 41 coincides with the long side 31a of the lens 31 and extends in the longitudinal direction D1, and the short side 41b of the positioning member 41 coincides with the short side 31b of the lens 31 and extends in the short side direction D2.

[0047] In the present embodiment, as shown in FIG. 2, the long side 41a of the positioning member 41 coincides with the long side 31a of the lens 31 at a distance T2 that is half of the dimension T1 of the lens 31 in the short side direction D from the laser emission point 16 (the center of the laser emission point 16 in the short side direction D2). With such a configuration, by making the corners of the positioning member 41 and the lens 31 coincide with each other, the laser emission point 16 and the lens center C in the short side direction D2 are in a coincident state. In the present embodiment, since the arrangement region R1 of the plurality of laser emission points 16 is unevenly distributed on the long side 15b side of the emission end face 15, in a state where the laser emission point 16 and the lens center C in the short side direction D2 coincide, a part of the lens 31 in the short side direction D2 protrudes toward the submount 12 side. However, as long as a part of the lens 31 in the short side direction D2 does not interfere with the lens 31 disposed on the emission end face 15 of another semiconductor laser bar 11, no particular problem occurs.

[0048] As shown in FIG. 3, the protruding length P of the positioning member from the emission end face 15 is defined by the thickness of the positioning member 41. The protruding length P of the positioning member from the emission end face 15 coincides with the back focus F of the lens 31. The back focus F corresponds to the distance from the rear end face of the lens 31 (the flat face on the emission end face 15 side here) to the focal point. The positioning member 41 functions as a spacer that aligns the back focus F of the lens 31 with the emission end face 15 when the lens 31 is attached to the emission end face 15 via the positioning member 41.

[0049] As an example, the length of the long side 41a of the positioning member 41 is about 10 μm to 5000 μm, and the length of the short side 41b of the positioning member 41 is about 10 μm to 100 μm. The thickness of the positioning member 41, that is, the protruding length P of the positioning member from the emission end face 15, is about 10 μm to 1000 μm. The distance T2, which is half of the dimension T1 of the lens 31 in the short-side direction D2 from the laser emission point 16, is about 20 μm to 100 μm.

[0050] Next, a method for manufacturing the semiconductor laser bar unit 4 described above will be described. FIG. 4 is a flowchart showing a method for manufacturing a semiconductor laser bar unit according to an embodiment of the present disclosure. As shown in FIG. 4, this method for manufacturing a semiconductor laser bar unit includes a first preparation step S01, a second preparation step S02, a formation step S03, a positioning step S04, and a bonding step S05.

[0051] The first preparation step S01 is a step of preparing a semiconductor laser bar 11 having an emission end face 15 extending in the longitudinal direction D1 and the short-side direction D2, with a plurality of laser emission points 16 arranged along the longitudinal direction D1 of the emission end face 15. The second preparation step S02 is a step of preparing an elongate lens 31 that can extend along the longitudinal direction D1 of the emission end face 15. The first preparation step S01 and the second preparation step S02 can be performed in any order.

[0052] The forming step S03 is a step in which a positioning member 41 is formed to position the lens 31 relative to the exit end face 15. In the forming step S03, a three-dimensional printing technology using micro-nano photolithography, such as a two-photon polymerization method or a surface projection micro-3D photolithography method, is used to form the positioning member 41 in the non-arranged region R2 of the exit end face 15, excluding the arrangement region R1 of the multiple laser emission points 16, as shown in Figure 5. At both ends 15e and 15f in the longitudinal direction D1 of the exit end face 15, rectangular positioning members 41 are formed in a front view of the exit end face 15, corresponding to the corners 15g and 15h.

[0053] The positioning step S04 is a step in which the lens 31 is positioned relative to the output end face 15. In positioning step S04, as shown in Figure 6, the positioning member 41 is used as an alignment mark to position the lens 31 relative to the output end face 15 so that the lens 31 faces the multiple laser output points 16. In the example in Figure 6, the corners of the positioning member 41 and the lens 31 are aligned. That is, in a front view, the lens 31 is superimposed on the positioning member 41 such that the long side 31a of the lens 31 coincides with the long side 41a of the positioning member 41, and the short side 31b of the lens 31 coincides with the short side 41b of the positioning member 41. The long side 41a of the positioning member 41 coincides with the long side 31a of the lens 31 at a distance T2 which is half the dimension T1 of the lens 31 in the short direction D2 from the laser output point 16. Therefore, by aligning the corners of the positioning member 41 and the lens 31, the laser emission point 16 and the lens center C in the short direction D2 coincide (see Figure 2).

[0054] The bonding step S05 involves bonding the lens 31 to the output end face 15 via the positioning member 41. In bonding step S05, the lens 31, which has been aligned with the positioning member 41, is bonded to the positioning member 41 using, for example, an adhesive. The adhesive may be placed on the contact surface between the positioning member 41 and the lens 31, or on the contact surface between the lens 31 and the positioning member 41. Bonding step S05 yields the semiconductor laser bar unit 4 shown in Figures 2 and 3.

[0055] As described above, in the semiconductor laser bar unit 4, a positioning member 41 for positioning the lens 31 relative to the output end face 15 is provided on the output end face 15. Because the positioning member 41 is directly provided on the output end face 15, the positioning accuracy of the lens 31 relative to the output end face 15 can be easily ensured even when the size of the output end face 15 and the lens 31 is small. Since the positioning member 41 is located in a non-arranged region R2 excluding the arrangement region R1 of the multiple laser output points 16, it is possible to suppress the effect of heat from light emission at the laser output points 16 on the positioning member 41, and to suppress the effect of stress when installing the positioning member 41 on the arrangement region R1 of the laser output points 16.

[0056] In this embodiment, the positioning member 41 is positioned at least at two locations in the non-arranged region R2. This allows the lens to be supported at two or more points by the positioning member, making it easier to position the lens 31 relative to the exit end face 15.

[0057] In this embodiment, the positioning members 41 are positioned at locations offset in the longitudinal direction D1 and the short direction D2 relative to the multiple laser emission points 16. In this embodiment, the positioning members are also positioned at both ends 15e and 15f of the emission end face 15 in the longitudinal direction D1. With this configuration, it is possible to more reliably suppress the effect of heat from the light emission at the laser emission points 16 on the positioning members 41, and the stress when installing the positioning members 41 on the arrangement region R1 of the laser emission points 16. Furthermore, it is possible to suppress the obstruction of light emitted from the laser emission points 16 by the positioning members 41.

[0058] In this embodiment, the positioning member 41 overlaps with the lens 31 when viewed from the direction opposite the exit end face 15 and the lens 31. The long side 41a of the positioning member 41 coincides with the long side 31a of the lens 31 at a distance T2 that is half the dimension of the lens 31 in the short direction D2 from the laser emission point 16. With this configuration, the center of the lens in the short direction D2 relative to the laser emission point 16 can be easily aligned simply by aligning the long side 31a of the lens 31 with the long side 41a of the positioning member 41.

[0059] In this embodiment, the positioning member 41 overlaps with the lens 31 when viewed from the direction opposite the exit end face 15 and the lens 31, and the short side 41b of the positioning member 41 coincides with the short side 31b of the lens 31. With this configuration, the lens 31 can be easily aligned with the exit end face 15 simply by aligning the short side 31b of the lens 31 with the short side 41b of the positioning member 41.

[0060] In this embodiment, the protrusion length P of the positioning member 41 from the exit end face 15 coincides with the back focus F of the lens. In this case, the positioning member 41 functions as a spacer to align the back focus F of the lens 31 with the exit end face 15, and based on the protrusion length P of the positioning member 41, the back focus F of the lens 31 can be accurately aligned with the exit end face 15.

[0061] This disclosure is not limited to the above embodiments. For example, in the above embodiments, the long side 41a of the positioning member 41 is aligned with the long side 15a of the exit end face 15, and the short side 41b of the positioning member 41 is aligned with the short side 15c or short side 15d of the exit end face 15. However, the short side 41b of the positioning member 41 may be aligned with the long side 15a of the exit end face 15, and the long side 41a of the positioning member 41 may be aligned with the short side 15c or short side 15d of the exit end face 15.

[0062] The positioning members 41 do not necessarily have to be arranged in two or more locations. For example, a single positioning member 41 extending in the longitudinal direction D1 may be configured to be biased towards the long side 15a in the non-arranged region R2 of the exit end face 15. In this case, the single positioning member 41 does not necessarily have to be arranged at both ends 15e and 15f in the longitudinal direction D1 of the exit end face 15, but may be arranged near the center in the longitudinal direction of the exit end face 15. Furthermore, the shape of the positioning member 41 in a front view of the exit end face 15 is not limited to a rectangular shape, but may be a square, rhombus, other polygonal shape, or a circular, elliptical, or oblong shape, among other shapes.

[0063] Furthermore, in the above embodiment, the positioning member 41 is formed on the exit end face 15 in the forming step S03. However, as shown in Figure 7, the first portion 41A of the positioning member 41 may be formed on the exit end face 15, and the second portion 41B of the positioning member 41 may be formed on the lens 31. In this case, in the positioning step S04 following the forming step S03, the lens 31 can be positioned relative to the exit end face 15 by bringing the first portion 41A and the second portion 41B together. With this method, the thickness of the positioning member 41 formed on the exit end face 15 can be reduced, so the stress when providing the positioning member 41 can be effectively suppressed from affecting the array region R1 of the laser emission point 16.

[0064] Furthermore, in the above embodiment, the length of the lens 31 in the longitudinal direction D1 is the same as the length of the exit end face 15 in the longitudinal direction D1. However, as shown in Figure 8, for example, the length of the lens 31 in the longitudinal direction D1 may be greater than the length of the exit end face 15 in the longitudinal direction D1. In the example in Figure 8, both ends of the lens 31 protrude equally in the longitudinal direction D1 from both ends of the exit end face 15. The protruding portions of both ends of the lens 31 may be fixed to fixing tabs J. The fixing tabs J may be, for example, plate-shaped or sheet-shaped, and a pair may be arranged so as to sandwich the semiconductor laser bar 11 in the longitudinal direction D1. For fixing the protruding portions of the lens 31 to the fixing tabs J, for example, UV-curing resin can be used.

[0065] When arranging the fixing tab J on the semiconductor laser bar 11, it is preferable, for example as shown in Figure 9, that the amount of protrusion of the fixing tab J from the exit end face 15 when the semiconductor laser bar 11 is viewed from the longitudinal direction D1 be less than or equal to the amount of protrusion of the positioning member 41 from the exit end face 15. This prevents the fixing tab J from interfering with the function of the positioning member 41 as a spacer when aligning the back focus F of the lens 31 with the exit end face 15. If the amount of protrusion of the fixing tab J from the exit end face 15 is less than the amount of protrusion of the positioning member 41 from the exit end face 15, the gap between the lens 31 and the fixing tab J can be filled with resin or the like.

[0066] 1... Semiconductor laser device, 3... Laminated structure, 4... Semiconductor laser bar unit, 11... Semiconductor laser bar, 15... Emission end face, 15e, 15f... Both ends, 16... Laser emission point, 31... Lens, 31a... Long side (one side extending in the longitudinal direction), 31b... Short side (one side extending in the short direction), 41... Positioning member, 41A... First part, 41B... Second part, 41a... Long side (one side extending in the longitudinal direction), 41b... Short side (one side extending in the short direction), K... Unit structure, D1... Longitudinal direction, D2... Short direction, R1... Alignment region, R2... Non-alignment region, T1... Dimension of the lens in the short direction, T2... Distance that is half the dimension of the lens in the short direction, P... Protrusion length of the positioning member, F... Back focus of the lens.

Claims

1. A semiconductor laser bar unit comprising: a semiconductor laser bar having an exit end face extending in a longitudinal direction and a transverse direction, wherein a plurality of laser emission points are arranged along the longitudinal direction of the exit end face; an elongated lens extending along the longitudinal direction so as to face the plurality of laser emission points; and a positioning member for positioning the lens with respect to the exit end face, wherein the positioning member is arranged in a non-arranged region of the exit end face excluding the area where the plurality of laser emission points are arranged, and is joined to the exit end face and the lens in the non-arranged region.

2. The semiconductor laser bar unit according to claim 1, wherein the positioning member is arranged at least at two locations in the non-arranged region.

3. The semiconductor laser bar unit according to claim 1 or 2, wherein the positioning member is positioned at a location offset in the longitudinal direction with respect to the plurality of laser emission points.

4. The semiconductor laser bar unit according to any one of claims 1 to 3, wherein the positioning member is positioned at a location offset in the short direction with respect to the plurality of laser emission points.

5. The semiconductor laser bar unit according to any one of claims 1 to 4, wherein the positioning members are arranged at both ends in the longitudinal direction of the output end face.

6. The semiconductor laser bar unit according to any one of claims 1 to 5, wherein the positioning member overlaps with the lens when viewed from the direction opposite to the exit end face and the lens, and one side of the positioning member extending in the longitudinal direction coincides with one side of the lens extending in the longitudinal direction at a distance from the laser emission point that is half the dimension of the lens in the short direction.

7. The semiconductor laser bar unit according to any one of claims 1 to 6, wherein the positioning member overlaps with the lens when viewed from the direction opposite to the exit end face and the lens, and one side of the positioning member extending in the short direction coincides with one side of the lens extending in the short direction.

8. The semiconductor laser bar unit according to any one of claims 1 to 7, wherein the protrusion length of the positioning member from the output end face coincides with the back focus of the lens.

9. A laminated structure having a plurality of unit structures bonded to a submount, wherein the semiconductor laser bar unit according to any one of claims 1 to 8 is bonded to each other in a state where the plurality of unit structures are stacked in the short direction.

10. A method for manufacturing a semiconductor laser bar unit, comprising: a first preparation step of preparing a semiconductor laser bar having an exit end face extending in a longitudinal direction and a transverse direction, wherein a plurality of laser emission points are arranged along the longitudinal direction of the exit end face; a second preparation step of preparing a long lens that can extend along the longitudinal direction of the exit end face; a forming step of forming a positioning member for positioning the lens relative to the exit end face in a non-aligned region of the exit end face excluding the region where the plurality of laser emission points are arranged; a positioning step of positioning the lens relative to the exit end face using the positioning member as an alignment mark so that the lens faces the plurality of laser emission points; and a bonding step of bonding the lens to the exit end face via the positioning member.

11. The method for manufacturing a semiconductor laser bar unit according to claim 10, wherein the positioning member is formed in the formation step using a three-dimensional printing technique by micro-nano photopolymerization.

12. The method for manufacturing a semiconductor laser bar unit according to claim 10 or 11, wherein in the forming step, a first portion of the positioning member is formed on the exit end face and a second portion of the positioning member is formed on the lens, and in the positioning step, the lens is positioned with respect to the exit end face by abutting the first portion and the second portion together.

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