Light-emitting device

Abstract

To solve the following problem: heat radiated from an internal semiconductor laser element while a light-emitting device is in operation cannot be effectively transferred to the outside of the light-emitting device.SOLUTION: A light-emitting device includes: a substrate made of a metal material and having an upper surface where a recessed portion having a bottom surface including a flat region is provided; a submount disposed on the bottom surface of the recessed portion; a semiconductor laser element disposed on the submount, and configured to emit laser light; a lens support member disposed on the submount; a lens supported by the lens support member, and configured to collimate or converge the laser light emitted from the semiconductor laser element; and a frame body made of a ceramic material and surrounding the semiconductor laser element. Each of the substrate and the semiconductor laser element has a rectangular shape having long sides and short sides in a top view, the long sides of the substrate and the long sides of the semiconductor laser element being parallel to one another.SELECTED DRAWING: Figure 1C

Description

[Technical field]

[0001] The present disclosure relates to a light emitting device. [Background technology]

[0002] Light-emitting devices that use a semiconductor laser element to emit laser light can be used in devices such as laser processing machines, projectors, and illumination light sources. In such light-emitting devices, due to manufacturing errors or deformation of the structure during the manufacturing process, heat generated from the semiconductor laser element during operation cannot be effectively transferred to the outside of the light-emitting device, and the heat may adversely affect the operation of the semiconductor laser element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-231864 A Summary of the Invention [Problem to be solved by the invention]

[0004] 2. Description of the Related Art In a light emitting device that uses a semiconductor laser element to emit laser light, it is required to effectively transfer heat generated from the semiconductor laser element during operation of the light emitting device to the outside of the light emitting device. [Means for solving the problem]

[0005] The light emitting device of the present disclosure comprises a substrate formed of a metal material having an upper surface on which a recess having a bottom surface including a planar region is provided, a submount arranged on the bottom surface of the recess, a semiconductor laser element arranged on the submount and emitting laser light, a lens support member arranged on the submount, a lens supported by the lens support member and for collimating or focusing the laser light emitted from the semiconductor laser element, and a frame formed of ceramics surrounding the semiconductor laser element, wherein the substrate and the semiconductor laser element are rectangular in top view, the rectangular shape has long sides and short sides, and the long sides of the substrate and the long sides of the semiconductor laser element are parallel to each other. Effect of the Invention

[0006] According to the embodiments of the present disclosure, heat generated from the semiconductor laser element during operation of the light emitting device can be effectively conducted to the outside of the light emitting device. [Brief description of the drawings]

[0007] [Figure 1A] FIG. 1A is a perspective view that illustrates a schematic configuration of a light emitting device according to an exemplary embodiment of the present disclosure. [Figure 1B] FIG. 1B is an exploded perspective view of the light emitting device shown in FIG. 1A. [Figure 1C] FIG. 1C is another exploded perspective view of the light emitting device shown in FIG. 1A. [Figure 1D] FIG. 1D is a perspective view of a frame included in the light emitting device shown in FIG. 1A, as viewed from below. [Figure 1E] FIG. 1E is a top view of the light emitting device shown in FIG. 1A without the cover. [Figure 1F] FIG. 1F is a cross-sectional view of the light-emitting device shown in FIG. 1A, taken parallel to the YZ plane. [Figure 1G] FIG. 1G is a diagram in which a part of the upper surface of the substrate is modified from the configuration shown in FIG. 1F. [Figure 2A] FIG. 2A is a cross-sectional view parallel to the YZ plane, which diagrammatically illustrates the configuration of a modified example of the light emitting device according to the present embodiment. [Figure 2B] FIG. 2B is a top view of a base configuration used in the light emitting device shown in FIG. 2A. [Figure 3A] FIG. 3A is a cross-sectional view parallel to the YZ plane for explaining an example of a process of a method for manufacturing a base used in the light emitting device according to this embodiment. [Figure 3B] FIG. 3B is a cross-sectional view parallel to the YZ plane for explaining an example of a process of a method for manufacturing a base used in the light emitting device according to this embodiment. [Figure 3C] FIG. 3C is a cross-sectional view parallel to the YZ plane for explaining an example of a process of a method for manufacturing a base used in the light emitting device according to this embodiment. [Figure 4A] FIG. 4A is a cross-sectional view parallel to the YZ plane for explaining an example of a process of a method for manufacturing a base used in a modified example of the light emitting device according to the present embodiment. [Figure 4B] FIG. 4B is a cross-sectional view parallel to the YZ plane for explaining an example of a process of a method for manufacturing a base used in a modified example of the light emitting device according to the present embodiment. [Figure 5A] FIG. 5A is an exploded perspective view of a laser light source. [Figure 5B] FIG. 5B is a cross-sectional view of the laser light source parallel to the YZ plane. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a light emitting device according to an embodiment of the present disclosure, a method for manufacturing a base used in the light emitting device, and a method for manufacturing the light emitting device will be described with reference to the drawings. Parts that appear in multiple drawings with the same reference numerals indicate the same or equivalent parts.

[0009] Furthermore, the embodiments described below are exemplified to embody the technical ideas of the present invention, and do not limit the present invention to the following. Furthermore, the description of the size, material, shape, relative arrangement, etc. of components is intended to be illustrative, and not to limit the scope of the present invention. The size and positional relationship of the components shown in each drawing may be exaggerated to make it easier to understand.

[0010] In this specification and claims, polygons such as triangles and quadrangles are referred to as polygons, including shapes in which the corners of the polygon have been processed by rounding, chamfering, removing corners, rounding, etc. Moreover, shapes in which processing has been applied not only to the corners (edges of the sides) but also to the middle parts of the sides are also referred to as polygons. In other words, shapes in which partial processing has been applied while leaving the polygon as the base are included in the interpretation of "polygon" described in this specification and claims.

[0011] (Embodiment) Hereinafter, a configuration example of a light emitting device according to an embodiment of the present disclosure will be described with reference to Fig. 1A and Fig. 1B. Fig. 1A is a perspective view that shows a schematic configuration of a light emitting device according to an exemplary embodiment of the present disclosure. Fig. 1B is an exploded perspective view of the light emitting device shown in Fig. 1A. The light emitting device 100 shown in Figs. 1A and 1B emits laser light L emitted from an internal semiconductor laser element to the outside of the light emitting device 100.

[0012] As shown in FIG. 1B, the light emitting device 100 includes a substrate 10, a laser light source 20, and a frame 40. The light emitting device 100 may further include a mirror member 30, a plurality of wires 41, and a cover 50. The substrate 10 has an upper surface 12. The laser light source 20 is a chip-on-submount type semiconductor laser light source having a semiconductor laser element 22. The mirror member 30 has a reflecting surface 32. The light emitting device 100 may further include a protection element such as a Zener diode and / or a temperature measuring element for measuring an internal temperature such as a thermistor. In this specification, the structure in which the substrate 10 and the frame 40 are joined together is also referred to as a "base 60." The base 60 accommodates the laser light source 20 and the mirror member 30.

[0013] 1B, the number of laser light sources 20 is one, but it may be more than one. When the number of laser light sources 20 is more than one, the number of mirror members 30 may be the same as the number of laser light sources 20, or may be less than the number of laser light sources 20. When the number of mirror members 30 is the same as the number of laser light sources 20, the mirror members 30 and the laser light sources 20 correspond one-to-one. When the number of mirror members 30 is less than the number of laser light sources 20, one mirror member 30 corresponds to two or more laser light sources 20.

[0014] In these figures, for reference, the mutually orthogonal X-axis, Y-axis, and Z-axis are shown diagrammatically. The direction of the X-axis arrow is referred to as the +X direction, and the opposite direction is referred to as the -X direction. When the ±X directions are not distinguished, they are simply referred to as the X direction. The same applies to the Y and Z directions. In this specification, for ease of explanation, the +Y direction is referred to as "upward" and the -Y direction is referred to as "downward". This does not limit the orientation of the light-emitting device when it is used, and the orientation of the light-emitting device is arbitrary.

[0015] FIG. 1C is another exploded perspective view of the light emitting device 100 shown in FIG. 1A. In FIG. 1C, the multiple wires 41 shown in FIG. 1B are omitted. FIG. 1D is a perspective view of the frame 40 included in the light emitting device 100 shown in FIG. 1A, seen from below. FIG. 1E is a top view of the light emitting device 100 shown in FIG. 1A without the cover 50. FIG. 1F is a cross-sectional view of the light emitting device 100 shown in FIG. 1A, parallel to the YZ plane. The thick arrow shown in FIG. 1F indicates the traveling direction of the laser light L emitted from the laser light source 20. FIG. 1G is a view in which a part of the upper surface 12 of the substrate 10 is modified from the configuration shown in FIG. 1F.

[0016] In the light emitting device 100 according to the present embodiment, as shown in FIG. 1C, a recess 13 having a bottom surface 15 is provided on the upper surface 12 of the substrate 10. The laser light source 20 and the mirror member 30 are disposed on the bottom surface 15 of the recess 13. The direction of travel of the laser light emitted from the laser light source 20 is the front of the laser light source 20, and the mirror member 30 is disposed so as to be located in front of the laser light source 20. As shown in FIG. 1F, the laser light L emitted from the laser light source 20 is reflected by the reflecting surface 32 of the mirror member 30 and travels in a direction away from the upper surface 12, and passes through the cover 50. In this way, the light emitting device 100 emits the laser light L from the cover 50. The light emitting device 100 is disposed, for example, on a planar arrangement surface. Also, for example, the lower surface 14 of the substrate 10 is disposed on a planar arrangement surface.

[0017] Unlike the light emitting device 100 according to this embodiment, the problem of the configuration in which the recess 13 is not provided on the upper surface 12 of the substrate 10 will be described below. When the substrate having no recess on the upper surface is bonded to the frame 40 via an inorganic bonding member such as a brazing material, heat is applied to the inorganic bonding member. If the thermal expansion coefficient of the substrate is higher than that of the frame 40, the substrate is deformed more than the frame 40 by the heat applied to the inorganic bonding member, and as a result, the substrate tends to warp upwardly. For example, if the substrate 10 is made of a metal material and the frame 40 is made of a ceramic having a lower thermal expansion coefficient than the substrate 10, the substrate may warp. In this specification, the configuration in which the substrate having no recess on the upper surface and the frame 40 are bonded is also referred to as the "base body".

[0018] As shown in FIG. 1C, the substrate has a rectangular shape when viewed from above in the +Y direction. The rectangular shape has long sides and short sides. When the substrate has a rectangular shape having long sides and short sides, the warping of the substrate is larger in the long side direction than in the short side direction. The semiconductor laser element 22 has a rectangular shape like the substrate. From the viewpoint of miniaturizing the light emitting device 100, the laser light source 20 is disposed on the upper surface of the substrate so that the long sides of the substrate and the long sides of the semiconductor laser element 22 are parallel to each other so as not to waste space. In that case, the lower surface of the laser light source 20 does not sufficiently contact the upper surface of the substrate due to the large warping of the substrate in the long side direction, so that the heat generated from the semiconductor laser element 22 during operation may not be effectively transferred to the substrate.

[0019] In contrast, in the light-emitting device 100 according to the present embodiment, if the substrate 10 is made of, for example, a metal material, the substrate 10 has plasticity, and therefore it is possible to provide the recess 13 on the upper surface 12 of the substrate 10 by a press device. The press device may, for example, include a stage having a planar support surface and a pressing unit having a planar lower end. The lower end of the pressing unit can be adjusted so as to be parallel to the support surface of the stage. The above-mentioned base body is placed on the stage of the press device so that the lower surface 14 of the substrate faces downward, and the pressing unit presses the upper surface of the substrate, thereby forming a recess on the upper surface of the substrate. In this manner, the substrate 10 having the recess 13 provided on the upper surface 12 is obtained. By pressing, the warping of the bottom surface 15 of the recess 13 is reduced compared to the upper surface of the substrate before the recess 13 is provided, and more specifically, the bottom surface 15 becomes planar.

[0020] In the light emitting device 100 according to this embodiment, the laser light source 20 is disposed on the flat bottom surface 15, so that the lower surface of the laser light source 20 is in uniform contact with the bottom surface 15. As a result, the heat generated from the semiconductor laser element 22 during operation can be effectively transferred to the substrate 10. This helps to improve the heat dissipation of the light emitting device 100.

[0021] Each component of the light emitting device 100 will be described below.

[0022] <Substrate 10> The substrate 10 has an upper surface 12 as shown in FIG. 1C. The upper surface 12 is provided with a recess 13 having a bottom surface 15. The substrate 10 further has a lower surface 14 located opposite the upper surface 12. The bottom surface 15 is a surface parallel to the XZ plane. The bottom surface 15 has a planar region as a whole. Like the bottom surface 15, the lower surface 14 is a surface parallel to the XZ plane. The lower surface 14 has a planar region as a whole. The bottom surface 15 and the lower surface 14 are parallel to each other. The normal direction of the bottom surface 15 is the +Y direction. In this specification, the normal direction of a surface means a direction perpendicular to the surface, which is a direction away from an object having the surface. The effects obtained by the bottom surface 15 being planar, the lower surface 14 being planar, and the bottom surface 15 and the lower surface 14 being parallel to each other will be described later.

[0023] If the depth of recess 13 is defined as the distance in the Y direction from the uppermost point on upper surface 12 of substrate 10 to the lowermost point on bottom surface 15 of substrate 10 using lower surface 14 as the height reference, the depth of recess 13 can be, for example, 5 μm or more and 30 μm or less. The flatness of the planar region on the entire bottom surface 15 is, for example, 10 μm or less, and the flatness of lower surface 14 is, for example, 20 μm or less.

[0024] According to JIS B 0621 "Definition and display of geometric deviation," flatness is defined as "the magnitude of deviation of a flat object from a geometrically correct plane (geometric plane)." Specifically, flatness corresponds to the distance between two imaginary perfectly flat planes when the target surface is sandwiched between them from above and below.

[0025] The substrate 10 is generally flat. The substrate 10 is rectangular when viewed from above. The substrate 10 has long sides and short sides. The recess 13 is also rectangular when viewed from above. The recess 13 has long sides and short sides. The recess 13 is preferably rectangular with rounded corners when viewed from above. The rounded corners can suppress stress concentration near the corners when the volume of the substrate 10 changes due to heat generated by the semiconductor laser element 22 during operation, compared to when the corners are not rounded.

[0026] The thermal conductivity of the substrate 10 can be, for example, not less than 50 W / m·K and not more than 500 W / m·K. The substrate 10 having such thermal conductivity can effectively transfer heat generated from the semiconductor laser element 22 during operation to the placement surface via the substrate 10.

[0027] The thermal expansion coefficient of the substrate 10 is, for example, 10×10 -6 [1 / K] or more 20×10 -6 [1 / K] or less. If the thermal expansion coefficient of the substrate 10 is higher than that of the frame 40, when the substrate is bonded to the frame 40 via an inorganic bonding member such as a brazing material, the substrate tends to warp upwardly due to the heat applied to the inorganic bonding member, as described above. If the substrate has plasticity, the warping of the substrate is alleviated by forming a recess on the upper surface of the substrate by a processing method such as pressing, and the substrate 10 shown in FIG. 1C is obtained. Compared to the upper surface before the recess is formed, the warping of the bottom surface 15 of the recess 13 is reduced, and more specifically, the bottom surface 15 of the recess 13 becomes flat.

[0028] The substrate 10 may be formed of at least one metal material selected from the group consisting of Cu, Al, and Ag. The metal material satisfies the above-mentioned thermal conductivity and thermal expansion coefficient, and has plasticity. The dimension of the substrate 10 in the X direction may be, for example, 1 mm or more and 10 mm or less, the dimension in the Y direction may be, for example, 0.1 mm or more and 5 mm or less, and the dimension in the Z direction may be, for example, 1 mm or more and 20 mm or less.

[0029] <Laser light source 20> The laser light source 20 is disposed on the bottom surface 15 of the recess 13 of the substrate 10, as shown in FIG. 1C. The laser light source 20 includes a submount 21, an end-emitting semiconductor laser element 22, a lens support member 23, and a fast-axis collimating lens 24, as shown in FIGS. 5A and 5B. The components of the laser light source 20 may be treated as components of the light-emitting device 100. FIG. 5A is an exploded perspective view of the laser light source 20. FIG. 5B is a cross-sectional view of the laser light source 20 parallel to the YZ plane. Each component of the laser light source 20 will be described below.

[0030] <Submount 21> As shown in FIG. 5A, the submount 21 has an upper surface 21s1 and a lower surface 21s2 that are parallel to the XZ plane. A metal film is provided on each of the upper surface 21s1 and the lower surface 21s2. The metal film provided on the upper surface 21s1 improves the bonding strength when the semiconductor laser element 22 and the lens support member 23 are bonded to the submount 21 via a bonding member. The metal film provided on the upper surface 21s1 may also be used to supply power to the semiconductor laser element 22. The metal film provided on the lower surface 21s2 improves the bonding strength when the substrate 10 and the laser light source 20 shown in FIG. 1C are bonded via a bonding member. The metal film provided on each of the upper surface 21s1 and the lower surface 21s2 also helps to transfer heat generated by the semiconductor laser element 22 during operation to the substrate 10 via the submount 21.

[0031] The submount 21 may be formed of the above-mentioned ceramics, for example, like the frame 40 shown in FIG. 1C. The submount 21 may be formed of the above-mentioned metal material, for example, like the substrate 10 shown in FIG. 1C. A part or the whole of the submount 21 may be formed of at least one selected from the group consisting of AlN, SiC, alumina, CuW, Cu, a laminated structure of Cu / AlN / Cu, and a metal matrix composite (Metal Matrix Compound: MMC). The MMC includes at least one selected from the group consisting of Cu, Ag, or Al, and diamond. Alternatively, a part or the whole of the submount 21 may be formed of other common materials.

[0032] The thermal conductivity of the submount 21 can be, for example, 10 [W / m K] or more and 800 [W / m K] or less. The submount 21 having such thermal conductivity can efficiently transfer the heat generated from the semiconductor laser element 22 during operation to the substrate 10. The thermal expansion coefficient of the submount 21 can be, for example, 2×10 -6 [1 / K] or more 2×10 -5 [1 / K] or less. When the semiconductor laser element 22 is bonded to the submount 21 via a bonding member, the submount 21 having such a thermal expansion coefficient can reduce the possibility of deformation of the submount 21 due to heat applied to the bonding member.

[0033] The submount 21 is disposed on the bottom surface 15 of the recess 13 . 1E, the outer edge of the recess 13 is inside the frame 40 in top view. Therefore, when the submount 21 and the substrate 10 are joined with a joining member, it is possible to reduce the possibility that the molten joining member will flow out to the frame 40 when the joining member is melted by heating and then cooled and solidified. The joining member may be, for example, at least one solder material selected from the group consisting of AuSn, SnCu, SnAg, and SnAgCu.

[0034] Furthermore, when the recess 13 is formed by pressing, a protrusion 16 may be formed around the recess 13, as shown in Fig. 1G. Even if the protrusion 16 is formed, it does not adversely affect the bonding strength between the substrate 10 and the frame 40. Furthermore, the protrusion 16 can reduce the possibility that the molten bonding material will flow out to the frame 40.

[0035] The submount 21 and the substrate 10 may be bonded together with a sintering material. In sintering, metal particles or metal powder are heated at a temperature lower than the melting point of the metal and baked to bond the members together. The sintering material may be, for example, a metal paste. The metal paste has an organic binder and a plurality of metal particles dispersed therein. The plurality of metal particles include at least one type of metal particles selected from the group consisting of Ag particles, Cu particles, Au particles, and other precious metal particles. Since the metal paste is flexible, the position of the submount 21 can be finely adjusted when the plurality of metal particles in the metal paste are sintered by heating to bond the submount 21 and the substrate 10.

[0036] <Semiconductor laser element 22> 5A, the semiconductor laser element 22 is supported by an upper surface 21s1 of the submount 21. That is, the semiconductor laser element 22 is disposed on the bottom surface 15 of the recess 13 via the submount 21.

[0037] The semiconductor laser element 22 has a rectangular shape when viewed from above. The rectangular shape has long sides and short sides. The length of the long side of the semiconductor laser element 22 can be, for example, 1000 μm or more and 10000 μm or less. The semiconductor laser element 22 can emit a high-power laser light of, for example, 10 W or more. The semiconductor laser element 22 generates a lot of heat when driven. The longer the semiconductor laser element 22 is, the more heat is generated. As shown in FIG. 1C, from the viewpoint of miniaturizing the light-emitting device 100, the laser light source 20 is disposed on the bottom surface 15 of the recess 13 so that the long sides of the substrate 10 and the long sides of the semiconductor laser element 22 are parallel to each other so as not to waste space. In this case, since the bottom surface 15 is flat, the lower surface of the submount 21 is in uniform contact with the bottom surface 15, so that the heat generated from the long semiconductor laser element 22 when driven can be effectively transferred to the substrate 10 via the submount 21. This helps to improve the heat dissipation of the light emitting device 100.

[0038] The semiconductor laser element 22 is disposed so as to emit laser light L toward the reflecting surface 32 of the mirror member 30. When the emission surface of the semiconductor laser element 22 is a plane parallel to the XY plane having the X direction as the longitudinal direction, the laser light L emitted from the semiconductor laser element 22 in the +Z direction spreads relatively fast in the YZ plane and spreads relatively slow in the XZ plane. The fast axis direction of the laser light L is parallel to the Y direction, and the slow axis direction is parallel to the X direction.

[0039] Since the semiconductor laser element 22 is supported by the submount 21, all of the laser light L that spreads as it travels can be incident on the reflecting surface 32 of the mirror member 30. The laser light L that spreads as it travels is reflected by the reflecting surface 32 and passes through the cover 50.

[0040] The distance in the Y direction from the upper surface 12 of the substrate 10 to the bottom surface 15 of the recess 13 is shorter than the distance in the Y direction from the upper surface of the semiconductor laser element 22 to the bottom surface 15 of the recess 13. The distance in the Y direction from the upper surface 12 of the substrate 10 to the bottom surface 15 of the recess 13 is shorter than the distance in the Y direction from the upper surface of the semiconductor laser element 22 to the lower surface of the semiconductor laser element 22. Due to such a distance relationship, even if the recess 13 is provided on the upper surface 12 of the substrate 10, it is not necessary to significantly change the size of the substrate 10 in order to provide the recess 13. In other words, the recess 13 can be provided without increasing the size of the light emitting device 100, and the heat dissipation of the light emitting device 100 can be improved.

[0041] Here, the distance in the Y direction from the upper surface 12 of the substrate 10 to the bottom surface 15 of the recess 13 means the distance in the Y direction from the uppermost point on the upper surface 12 of the substrate 11 to the lowermost point on the bottom surface 15 of the recess 13. The distance in the Y direction from the upper surface of the semiconductor laser element 22 to the bottom surface 15 of the recess 13 means the distance in the Y direction from the upper surface of the semiconductor laser element 22 to the lowermost point on the bottom surface 15 of the recess 13.

[0042] The semiconductor laser element 22 has an emission surface 22e, one of two end surfaces intersecting in the Z direction, and emits laser light in the +Z direction from the emission surface 22e. As the laser light travels in the +Z direction, it spreads at different speeds in the YZ plane and the XZ plane. The laser light spreads relatively quickly in the YZ plane and relatively slowly in the XZ plane. When not collimated, the spot of the laser light has an elliptical shape in the far field in the XY plane, with the major axis in the Y direction and the minor axis in the X direction.

[0043] The main part of the laser beam is defined as a part whose intensity is 1 / e2 or more of the peak intensity in any plane perpendicular to the traveling direction of the laser beam, where e is the base of the natural logarithm. In this specification, the spread of the laser beam means the spread of the main part of the laser beam.

[0044] The semiconductor laser element 22 can emit violet, blue, green or red laser light in the visible region, or infrared or ultraviolet laser light in the invisible region. The emission peak wavelength of the violet light is preferably in the range of 400 nm to 420 nm, more preferably in the range of 400 nm to 415 nm. The emission peak wavelength of the blue light is preferably in the range of more than 420 nm to 495 nm, more preferably in the range of 440 nm to 475 nm. The emission peak wavelength of the green light is preferably in the range of more than 495 nm to 570 nm, more preferably in the range of 510 nm to 550 nm. The emission peak wavelength of the red light is preferably in the range of 605 nm to 750 nm, more preferably in the range of 610 nm to 700 nm.

[0045] The semiconductor laser element 22 that emits violet, blue, and green laser light includes a laser diode containing a nitride semiconductor material. Examples of the nitride semiconductor material that can be used include GaN, InGaN, and AlGaN. The semiconductor laser element 22 that emits red laser light includes a laser diode containing an InAlGaP-based, GaInP-based, GaAs-based, and AlGaAs-based semiconductor material.

[0046] Instead of the end-emitting semiconductor laser element 22, a surface-emitting semiconductor laser element such as a VCSEL (Vertical-Cavity Surface-Emitting Laser) element may be used. The surface-emitting semiconductor laser element is arranged so that the laser light emitted from the semiconductor laser element travels in the +Z direction. Alternatively, the surface-emitting semiconductor laser element may be arranged so that the laser light emitted from the semiconductor laser element travels in the +Y direction. In this case, there is no need to provide a mirror member 30, which will be described later.

[0047] <Lens support member 23> As shown in FIG. 5A, the lens support member 23 is supported by the upper surface 21s1 of the submount 21. The lens support member 23 may be disposed on the submount 21 so as to be supported by the front or side surface of the submount 21. The lens support member 23 has two columnar parts 23a and a connecting part 23b located between the two columnar parts 23a and connecting the two columnar parts 23a. The two columnar parts 23a are located on both sides of the semiconductor laser element 22, and the connecting part 23b is located above the emission surface 22e side of the semiconductor laser element 22. The lens support member 23 supports the fast axis collimating lens 24 by the end faces 23as of the two columnar parts 23a. The lens support member 23 is located so as to straddle the semiconductor laser element 22, and does not prevent the laser light emitted from the semiconductor laser element 22 from entering the fast axis collimating lens 24.

[0048] The lens support member 23 may be formed of the above-mentioned ceramics, for example, similar to the frame 40 shown in Fig. 1C. The lens support member 23 may be formed of the above-mentioned light-transmitting material, for example, similar to the cover 50 shown in Fig. 1C. The lens support member 23 may be formed of at least one alloy selected from the group consisting of Kovar and CuW. The lens support member 23 may be formed of Si, for example.

[0049] Since the semiconductor laser element 22 and the lens support member 23 are disposed on the submount 21, the relative positional relationship between the semiconductor laser element 22 and the fast axis collimator lens 24 is fixed regardless of where the laser light source 20 is disposed. Therefore, no deviation occurs in the positional relationship.

[0050] <Fast axis collimating lens 24> As shown in FIG. 5A, the fast axis collimating lens 24 may be, for example, a cylindrical lens having a uniform cross-sectional shape in the X direction. The fast axis collimating lens 24 has a flat surface on the light incident side and a convex curved surface on the light exit side. The convex curved surface has a curvature in the YZ plane. The focal point of the fast axis collimating lens 24 approximately coincides with the center of the light emitting point in the exit surface 22e of the semiconductor laser element 22. As shown in FIG. 5B, the fast axis collimating lens 24 collimates the laser light emitted in the +Z direction from the exit surface 22e of the semiconductor laser element 22 in the fast axis direction in the YZ plane. In this specification, "collimate" means not only to make the laser light L parallel, but also to reduce the spread angle of the laser light L. The region surrounded by the dashed line shown in FIG. 5B is a region where the intensity of the laser light is 1 / e of its peak intensity. 2 The fast axis collimating lens 24 may be formed of at least one light-transmitting material selected from the group consisting of, for example, glass, silicon, quartz, synthetic quartz, sapphire, and transparent ceramics.

[0051] 1F, the fast axis collimating lens 24 is located between the upper surface 12 of the substrate 10 and the lower surface 54 of the cover 50, and is located on the optical path of the laser light L. Since the fast axis collimating lens 24 is disposed inside the sealed space formed by the substrate 10, the frame 40, and the cover 50, the laser light L can be collimated before it spreads too much. Therefore, the fast axis collimating lens 24 can be made compact.

[0052] Note that a collimating lens that collimates the laser light L emitted from the semiconductor laser element 22 not only in the YZ plane but also in the XZ plane may be used instead of the fast axis collimating lens 24. Alternatively, a focusing lens that focuses the laser light L emitted from the semiconductor laser element 22 may be used instead of the fast axis collimating lens 24.

[0053] From the above, the laser light source 20 arranged on the flat bottom surface 15 emits the laser light L in the +Z direction parallel to the bottom surface 15, as shown in FIG. 1F. Even if the traveling direction of the laser light L emitted from the laser light source 20 is not strictly parallel to the +Z direction, it is acceptable as long as the absolute value of the angle between the traveling direction of the laser light L emitted from the laser light source 20 and the +Z direction is 0.5° or less. The laser light L emitted from the laser light source 20 is collimated in the YZ plane, but is not collimated in the XZ plane. The semiconductor laser element 22 included in the laser light source 20 is sealed by the substrate 10, the frame 40, and the cover 50, as shown in FIG. 1F. This sealing is preferably airtight. The effect of the airtight sealing is higher as the wavelength of the laser light L emitted from the semiconductor laser element 22 becomes shorter. This is because, in a configuration in which the emission surface of the semiconductor laser element 22 is not hermetically sealed and is exposed to the outside air, the shorter the wavelength of the laser light L, the higher the possibility that the emission surface will deteriorate due to dust collection during operation. In other words, by hermetically sealing the semiconductor laser element 22, the emission surface of the semiconductor laser element 22 can be protected from dust collection. As shown in FIG. 1C, from the viewpoint of miniaturizing the light-emitting device 100, the laser light source 20 is disposed on the bottom surface 15 of the recess 13 so that the long sides of the substrate 10 and the long sides of the semiconductor laser element 22 are parallel to each other so as not to waste space. By miniaturizing the light-emitting device 100, hermetic sealing becomes easier.

[0054] <Mirror member 30> As shown in FIG. 1C, the mirror member 30 is disposed on the bottom surface 15 of the recess 13 of the substrate 10. The mirror member 30 and the laser light source 20 are disposed side by side in the long side direction of the substrate 10. The mirror member 30 has a uniform cross-sectional shape in the X direction. The cross-sectional shape is roughly triangular. The mirror member 30 has a lower surface, a rear surface, and a slope connecting the lower surface and the rear surface. The lower surface is parallel to the XZ plane, and the rear surface is parallel to the XY plane. The normal direction of the slope is a direction parallel to the YZ plane, and forms an acute angle with the +Y direction and an acute angle with the -Z direction. The angle between the lower surface of the mirror member 30 and the slope is 45°, but is not limited to this angle and may be, for example, 30° to 60°.

[0055] The mirror member 30 has a planar reflecting surface 32. The reflecting surface 32 is inclined with respect to the upper surface 12 of the substrate 10 and faces obliquely upward. In this specification, obliquely upward means a direction that forms an angle of 30° to 60° with the +Y direction. As long as the reflecting surface 32 can receive the laser light L emitted from the laser light source 20 and the normal direction of the reflecting surface 32 is a direction that forms an angle of 30° to 60° with the +Y direction, the normal direction of the reflecting surface 32 may or may not be parallel to the YZ plane.

[0056] 1F, the reflecting surface 32 of the mirror member 30 disposed on the planar bottom surface 15 reflects the laser light L emitted from the laser light source 20 to change the traveling direction of the laser light L to a direction away from the top surface 12 of the substrate 10. In the example shown in FIG. 1F, the direction away from the top surface 12 of the substrate 10 is the +Y direction perpendicular to the bottom surface 15 of the recess 13. Even if the traveling direction of the laser light L reflected by the reflecting surface 32 is not strictly parallel to the +Y direction, this is permissible as long as the absolute value of the angle between the traveling direction of the laser light L reflected by the reflecting surface 32 and the +Y direction is 0.5° or less.

[0057] Unlike the light emitting device 100 according to the present embodiment, in the example shown in FIG. 1F, when the base 60 is replaced with the above-mentioned base body, the concave portion 13 is not provided on the upper surface of the substrate in the base body, and therefore the substrate warpage is not alleviated. When the laser light source 20 and the mirror member 30 are arranged on the upper surface of the substrate along the upward convexity, the relative positional relationship between the laser light source 20 and the mirror member 30 is shifted. As a result, the traveling direction of the laser light L emitted from the laser light source 20 is shifted from the +Z direction, and the traveling direction of the laser light L emitted from the laser light source 20 and reflected by the reflecting surface 32 of the mirror member 30 is shifted from the +Y direction. As a result, the traveling direction of the laser light L emitted to the outside of the light emitting device is shifted from the +Y direction, which is the traveling direction in design.

[0058] In contrast, in the light emitting device 100 according to the present embodiment, the laser light source 20 and the mirror member 30 are disposed on the planar bottom surface 15 of the recess 13, thereby reducing the deviation of the relative positional relationship between the laser light source 20 and the mirror member 30. Therefore, the deviation between the traveling direction of the laser light L emitted from the laser light source 20 and the +Z direction is reduced, and the deviation between the traveling direction of the laser light L emitted from the laser light source 20 and reflected by the reflecting surface 32 of the mirror member 30 and the +Y direction is reduced. As a result, it is possible to reduce the deviation between the traveling direction of the laser light L emitted to the outside of the light emitting device 100 and the +Y direction, which is the designed traveling direction. Note that the designed traveling direction is not limited to the +Y direction, but may be any direction.

[0059] The mirror member 30 includes, for example, a base having an inclined surface and a reflecting surface provided on the inclined surface. The base may be made of at least one selected from the group consisting of glass, quartz, synthetic quartz, sapphire, ceramics, silicon, metal, and dielectric materials. The reflecting surface may be made of a reflective material such as a dielectric multilayer film and a metal material. The reflecting surface corresponds to the reflecting surface 32.

[0060] Alternatively, the mirror member 30 may include, for example, a base having an inclined surface, and the base may be made of the above-mentioned reflective material. In this case, the inclined surface of the base corresponds to the reflective surface 32.

[0061] <Frame 40> The frame 40 is located around the upper surface 12 of the substrate 10 as shown in FIG. 1B, and supports the cover 50 as shown in FIG. 1A. The frame 40 surrounds the laser light source 20 and the mirror member 30 in a top view as shown in FIG. 1B. The frame 40 has a protruding portion 43 protruding inward from the inner surface as shown in FIG. 1C. In the example shown in FIG. 1E, the protruding portion 43 protrudes toward both side surfaces and the back surface of the submount 21. The protruding portion 43 may further protrude toward the front surface of the submount 21. The protruding portion 43 may protrude only from both side surfaces. The front surface of the submount 21 is located on the same side as the emission surface of the semiconductor laser element 22, and the back surface of the submount 21 is located on the opposite side to the emission surface of the semiconductor laser element 22. The both side surfaces of the submount 21 connect the front surface and the back surface of the submount 21.

[0062] As shown in Fig. 1C, the frame 40 has a first upper surface 42a and a second upper surface 42b. The second upper surface 42b is the upper surface of the protruding portion 43, is located lower than the first upper surface 42a, and is surrounded by the first upper surface 42a in a top view. In the example shown in Fig. 1E, the second upper surface 42b is generally U-shaped.

[0063] The first upper surface 42a is provided with a first bonding region 46a and an outer region 47 surrounding the first bonding region 46a. The first bonding region 46a and the outer region 47 are generally rectangular and annular in shape. The first bonding region 46a improves the bonding strength when the cover 50 and the frame body 40 are bonded via a bonding member such as a solder material. The outer region 47 reduces the possibility that the bonding member bonding the cover 50 will flow beyond the outer region 47. The first bonding region 46a and the outer region 47 surround the laser light source 20 and the mirror member 30 in a top view, as shown in FIG. 1E. The first upper surface 42a is further provided with a first conductive region 48a and a second conductive region 48b that are electrically insulated from each other in the -Z direction from the first bonding region 46a and the outer region 47.

[0064] The second upper surface 42b is provided with a third conductive region 48c and a fourth conductive region 48d that are electrically insulated from each other. The third conductive region 48c is electrically connected to the first conductive region 48a via an internal wiring. The fourth conductive region 48d is electrically connected to the second conductive region 48b via an internal wiring. As shown in FIG. 1E, in a top view, the laser light source 20 and the mirror member 30 are located between a portion of the third conductive region 48c that extends in the Z direction and a portion of the fourth conductive region 48d that extends in the Z direction. The third conductive region 48c is electrically connected to the semiconductor laser element 22 via the upper surface of the submount 21 and some of the wires 41. The fourth conductive region 48d is electrically connected to the semiconductor laser element 22 via the remaining wires 41. Therefore, by applying a voltage between the first conductive region 48a and the second conductive region 48b, it is possible to supply power to the laser light source 20.

[0065] As shown in FIG. 1D, the frame 40 further has a first lower surface 44a and a second lower surface 44b. The second lower surface 44b partially has the lower surface of the protruding portion 43, is located above the first lower surface 44a, and is surrounded by the first lower surface 44a when viewed from below in the -Y direction. The second lower surface 44b has a generally rectangular ring shape. A part or the whole of the substrate 10 shown in FIG. 1C is accommodated in a space surrounded by the step between the first lower surface 44a and the second lower surface 44b. When viewed through the frame 40, the outer periphery of the second lower surface 44b surrounds the outer periphery of the upper surface 12 of the substrate 10 when viewed from above, and the inner periphery of the second lower surface 44b is surrounded by the outer periphery of the upper surface 12 of the substrate 10 when viewed from above.

[0066] As shown in FIG. 1D, the frame 40 has an opening 45 penetrating from the first upper surface 42a to the first lower surface 44a. The opening 45 has a second lower surface 44b corresponding to a step on the lower surface side of the inner surface. A second bonding area 46b is provided on the entire second lower surface 44b. The peripheral area of ​​the upper surface 12 of the substrate 10 is bonded to the second bonding area 46b provided on the step via an inorganic bonding member such as a brazing material. An example of the brazing material is silver brazing. The second bonding area 46b improves the bonding strength when the substrate 10 and the frame 40 are bonded via an inorganic bonding member. The melting point of the brazing material is higher than the melting point of the solder material. Therefore, when the substrate 10 and the frame 40 are bonded by heating the brazing material, and then the solder material is heated to bond the substrate 10 and the laser light source 20, the possibility that the substrate 10 and the frame 40 will come off due to the heat applied to the solder material can be reduced. As the inorganic bonding material, for example, AuSn, Au paste, or Ag paste may be used.

[0067] 1D, the second bonding region 46b is provided on the entire second lower surface 44b, but is not limited to this example. The second bonding region 46b may be provided on a part of the second lower surface 44b.

[0068] As shown in FIG. 1F, the first lower surface 44a of the frame 40 is located higher than the lower surface 14 of the substrate 10. In other words, the distance in the Y direction from the upper surface 12 of the substrate 10 to the lower surface 14 of the substrate 10 is longer than the distance in the Y direction from the upper surface 12 of the substrate 10 to the first lower surface 44a of the frame 40. Here, the distance in the Y direction from the upper surface 12 of the substrate 10 to the lower surface 14 of the substrate 10 means the distance in the Y direction from the uppermost position of the upper surface 12 of the substrate 10 to the lowermost position of the lower surface 14 of the substrate 10. The distance in the Y direction from the upper surface 12 of the substrate 10 to the first lower surface 44a of the frame 40 means the distance in the Y direction from the uppermost position of the upper surface 12 of the substrate 10 to the lowermost position of the first lower surface 44a of the frame 40.

[0069] When the light emitting device 100 is placed on a planar placement surface, the lower surface 14 of the substrate 10 is supported by the placement surface. The lower surface 14 of the substrate 10 is joined to the placement surface via a joining member such as a solder material. When the lower surface 14 of the substrate 10 is planar, the entire lower surface 14 is uniformly in contact with the placement surface via the joining member, so that heat generated from the semiconductor laser element 22 during operation can be effectively transferred to the placement surface via the substrate 10. This helps to improve the heat dissipation of the light emitting device 100. Since the entire lower surface 14 is uniformly in contact with the placement surface via the joining member, the light emitting device 100 can also be stably placed. Furthermore, when the light emitting device 100 is placed on a planar placement surface, the bottom surface 15 of the recess 13 is parallel to the lower surface 14 of the substrate 10, so that the deviation between the traveling direction of the laser light L emitted to the outside of the light emitting device 100 and the +Y direction, which is the traveling direction in design, can be more effectively reduced.

[0070] The first lower surface 44a of the frame 40 may be located on the same plane as the lower surface 14 of the substrate 10. In other words, the distance in the Y direction from the upper surface 12 of the substrate 10 to the lower surface 14 of the substrate 10 may be the same as the distance in the Y direction from the upper surface 12 of the substrate 10 to the first lower surface 44a of the frame 40. Alternatively, the first lower surface 44a of the frame 40 may be located lower than the lower surface 14 of the substrate 10 as long as it does not interfere with bonding the substrate 10 to the placement surface via an inorganic bonding member. In other words, the distance in the Y direction from the upper surface 12 of the substrate 10 to the lower surface 14 of the substrate 10 may be shorter than the distance in the Y direction from the upper surface 12 of the substrate 10 to the first lower surface 44a of the frame 40. When the first lower surface 44a of the frame 40 is located lower than the lower surface 14 of the substrate 10, it is preferable that only the lower surface 14 of the substrate 10 is in contact with the placement surface. The arrangement surface overlaps the lower surface 14 of the substrate 10 but does not overlap the first lower surface 44a of the frame body 40 in a top view.

[0071] Even if the first lower surface 44a of the frame 40 is located lower than the lower surface 14 of the substrate 10, the lower surface 14 of the substrate 10 is in contact with the placement surface, so that heat generated from the semiconductor laser element 22 during operation can be effectively transferred to the placement surface via the substrate 10. This helps to improve the heat dissipation of the light emitting device 100. Furthermore, even if the first lower surface 44a of the frame 40 is located lower than the lower surface 14 of the substrate 10, only the lower surface 14 of the substrate 10 is in contact with the placement surface, so that the bottom surface 15 of the recess 13 is parallel to the placement surface. Therefore, the effect of reducing deviation in the traveling direction of the laser light L by pressing the substrate 10 can be fully exerted.

[0072] The frame 40 may be made of a ceramic material selected from the group consisting of AlN, SiN, SiC, and alumina. The thermal expansion coefficient of the frame 40 may be, for example, 2×10 -6 [1 / K] or more 15×10 -6 The dimension of the frame 40 in the X direction may be, for example, 3 mm or more and 30 mm or less, the maximum dimension in the Y direction may be, for example, 1 mm or more and 5 mm or less, and the dimension in the Z direction may be, for example, 3 mm or more and 30 mm or less.

[0073] The first bonding region 46a, the second bonding region 46b, the outer region 47, and the conductive regions 48a to 48d may be formed of at least one metal material selected from the group consisting of Ag, Cu, W, Au, Ni, Pt, and Pd. The first bonding region 46a, the outer region 47, and the conductive regions 48a to 48d may be formed, for example, by providing a metal film on the entire first upper surface 42a and the second upper surface 42b and patterning the metal film by etching.

[0074] <Cover 50> The cover 50 is supported by a first upper surface 42a of the frame 40 shown in FIG. 1C. The cover 50 has an upper surface 52 and a lower surface 54 as shown in FIG. 1B. The lower surface 54 of the cover 50 faces the upper surface 12 of the substrate 10, and the upper surface 52 of the cover 50 is located opposite the lower surface 54 of the cover 50. Since the lower surface 54 of the cover 50 faces the upper surface 12 of the substrate 10, it may be called the "opposing surface". The cover 50 is located above the laser light source 20, more specifically, the semiconductor laser element 22. The cover 50 is further located above the mirror member 30.

[0075] The cover 50 transmits the laser light L reflected by the reflecting surface 32. More specifically, the cover 50 has a light-transmitting portion 56 as shown in FIG. 1C, and the light-transmitting portion 56 transmits the laser light L reflected by the reflecting surface 32.

[0076] The cover 50 may have a light-shielding film 58 in a location other than the light-transmitting region through which the laser light L passes. In the example shown in FIG. 1C, the cover 50 has a light-shielding film 58 at least around the light-transmitting region of the lower surface 54 through which the laser light L passes. The light-transmitting region corresponds to the lower surface of the light-transmitting portion 56. In the example shown in FIG. 1C, the light-transmitting region is rectangular, but is not limited to this shape. The shape of the light-transmitting region may be, for example, circular or elliptical. The light-shielding film 58 may be provided on the upper surface 52 of the cover 50.

[0077] The light-shielding film 58 reduces the possibility that stray light other than the laser light L generated inside the light-emitting device 100 leaks outside the light-emitting device 100. The light-shielding film 58 further reduces the possibility that return light of the laser light L emitted to the outside of the light-emitting device 100 reaches the laser light source 20. If irradiation by return light can be reduced, the laser light source 20 is less likely to be damaged.

[0078] 1C , the light-shielding film 58 is provided on the entire area of ​​the lower surface 54 except for the lower surface of the light-transmitting portion 56. The light-shielding film 58 thus provided further reduces the possibility that the stray light will leak to the outside of the light-emitting device 100 and the possibility that the return light will reach the laser light source 20.

[0079] Of the cover 50, the light-transmitting portion 56 that transmits the laser light L may have a transmittance of, for example, 60% or more, and preferably 80% or more, to the laser light L. The remaining portions of the cover 50 may or may not have such light-transmitting properties.

[0080] The cover 50 may be formed of at least one light-transmitting material selected from the group consisting of, for example, glass, silicon, quartz, synthetic quartz, sapphire, and transparent ceramics. The dimension of the cover 50 in the X direction may be, for example, 3 mm or more and 15 mm or less, the dimension in the Y direction may be, for example, 0.1 mm or more and 1.5 mm or less, and the dimension in the Z direction may be, for example, 1 mm or more and 20 mm or less.

[0081] The light-shielding film 58 may be formed of the above-mentioned metal material, similar to the first bonding region 46a, the second bonding region 46b, the outer region 47, and the conductive regions 48a to 48d. The light-shielding film 58 may be formed, similar to the first bonding region 46a, the second bonding region 46b, the outer region 47, and the conductive regions 48a to 48d, by providing a metal film over the entire lower surface 54 of the cover 50 and patterning the metal film by etching.

[0082] The peripheral region of the light-shielding film 58 is joined via a joining member such as a solder material to the first joining region 46a provided on the first upper surface 42a of the frame body 40. When the light-shielding film 58 is made of the above-mentioned metal material, the light-shielding film 58 improves the joining strength when the cover 50 and the frame body 40 are joined via the joining member.

[0083] 1A to 1C, the cover 50 has a flat plate shape, but is not limited to this shape. In the light-emitting device 100, the cover 50 may have a box shape with an open bottom. In such a shape, the frame 40 and the cover 50 are joined together so that the bottom surface of the cover 50 is supported by the first top surface 42a of the frame 40.

[0084] From the above, in the light emitting device 100 according to this embodiment, from the viewpoint of miniaturizing the light emitting device 100, the laser light source 20 is arranged on the bottom surface 15 of the recess 13 so that the long sides of the semiconductor laser element 22 and the long sides of the substrate 10 are parallel to each other so as not to waste space. In this case, since the bottom surface 15 is flat, the lower surface of the submount 21 is in uniform contact with the bottom surface 15, so that the heat generated from the long semiconductor laser element 22 during operation can be effectively transferred to the substrate 10 via the submount 21. This helps to improve the heat dissipation of the light emitting device 100.

[0085] Furthermore, in the light emitting device 100 according to this embodiment, when the light emitting device 100 is placed on a planar placement surface, the entire planar lower surface 14 of the substrate 10 is in uniform contact with the placement surface via the bonding member, so that heat generated from the semiconductor laser element 22 during operation can be effectively transferred to the placement surface via the substrate 10. Since the entire planar lower surface 14 of the substrate 10 is in uniform contact with the placement surface via the bonding member, the light emitting device 100 can also be stably placed.

[0086] Furthermore, in the light emitting device 100 according to this embodiment, by arranging the laser light source 20 and the mirror member 30 on the planar bottom surface 15 of the recess 13, it is possible to reduce the deviation between the traveling direction of the laser light L emitted from the laser light source 20 and the +Z direction, and to reduce the deviation between the traveling direction of the laser light L reflected by the reflecting surface 32 and the +Y direction. As a result, it is possible to reduce the deviation between the traveling direction of the laser light L emitted to the outside of the light emitting device 100 and the +Y direction, which is the designed traveling direction.

[0087] Furthermore, in the light-emitting device 100 according to this embodiment, when the light-emitting device 100 is placed on a planar placement surface, the bottom surface 15 of the recess 13 and the lower surface 14 of the substrate 10 are parallel to each other, making it possible to more effectively reduce the deviation between the propagation direction of the laser light L emitted to the outside of the light-emitting device 100 and the +Y direction, which is the designed propagation direction.

[0088] The light emitting device 100 according to the present embodiment may further include another mirror member arranged on the upper surface 52 of the cover 50. The reflecting surface of the other mirror member reflects the laser light L reflected by the reflecting surface 32 and transmitted through the cover 50 in a direction different from the +Y direction. The direction different from the +Y direction may be, for example, the +Z direction. The light emitting device 100 according to the present embodiment may further include a slow-axis collimating lens arranged on the upper surface 52 of the cover 50 shown in FIG. 1B. The slow-axis collimating lens collimates the laser light L reflected by the reflecting surface 32 and transmitted through the cover 50 in the slow-axis direction in the XY plane. Alternatively, the light emitting device 100 according to the present embodiment may further include both the other mirror member and the slow-axis collimating lens arranged on the upper surface 52 of the cover 50. The reflecting surface of the other mirror member reflects the laser light L reflected by the reflecting surface 32 and transmitted through the cover 50 in a direction different from the +Y direction. The slow-axis collimating lens collimates the laser light reflected by the reflecting surface of the other mirror member in the slow-axis direction.

[0089] (Modifications of the Light Emitting Device 100) Next, a modified example of the light emitting device 100 according to the present embodiment will be described with reference to Figs. 2A and 2B. Fig. 2A is a cross-sectional view parallel to the YZ plane, which shows a schematic configuration of a modified example of the light emitting device 100 according to the present embodiment. The light emitting device 110 shown in Fig. 2A differs from the light emitting device 100 according to the present embodiment in that the light emitting device 110 includes a substrate 10V instead of the substrate 10. In this specification, the configuration in which the substrate 10V and the frame body 40 are joined together is also referred to as a "base 60V". Fig. 2B is a top view of the configuration of the base 60V used in the light emitting device 110 shown in Fig. 2A.

[0090] As shown in Fig. 2A, the substrate 10V has an upper surface 12 and a lower surface 14. The upper surface 12 is provided with a recess 13 having a bottom surface 15. The bottom surface 15 of the recess 13 has a first bottom surface 15a on which the laser light source 20 is disposed, and a second bottom surface 15b on which the mirror member 30 is disposed. The difference between the embodiment and the modified example is the presence or absence of the second bottom surface 15b of the recess 13. The configuration other than the second bottom surface 15b is as described above.

[0091] Taking the lower surface 14 of the substrate 10 as a reference height, the second bottom surface 15b is located lower than the first bottom surface 15a. Therefore, the bottom surface 15 has a step formed between the first bottom surface 15a and the second bottom surface 15b. The recess 13, more specifically, the outer edge of the first bottom surface 15a of the recess 13 has a rectangular shape with rounded corners when viewed from above. The same is true for the outer edge of the second bottom surface 15b inside the recess 13. The rounded corners of the recess 13 can suppress the concentration of stress near the corners of the recess 13. The lower surface 14 of the substrate 10V is the same as the lower surface 14 of the substrate 10 shown in FIG. 1C.

[0092] If the lower surface 14 of the substrate 10V is taken as a height reference and the distance in the Y direction from the uppermost position on the upper surface 12 to the lowermost position on the first bottom surface 15a is taken as the first depth of the recess 13, the first depth of the recess 13 may be, for example, 5 μm or more and 30 μm or less. If the lower surface 14 of the substrate 10V is taken as a height reference and the distance in the Y direction from the uppermost position on the upper surface 12 to the lowermost position on the second bottom surface 15b is taken as the second depth of the recess 13, the second depth of the recess 13 may be, for example, 5 μm or more and 50 μm or less. The first bottom surface 15a and the second bottom surface 15b are planar and parallel to each other. The bottom surface 15 has a step between the first bottom surface 15a and the second bottom surface 15b, but has planar regions on the first bottom surface 15a and the second bottom surface 15b. The bottom surface 14 of the substrate 10V is planar, as are the first bottom surface 15a and the second bottom surface 15b. The bottom surface 14 of the substrate 10V has a planar region as a whole. The first bottom surface 15a and the second bottom surface 15b are parallel to the bottom surface 14 of the substrate 10V. The flatness of the first bottom surface 15a and the second bottom surface 15b, which are the planar regions of the bottom surface 15, is, for example, 10 μm or less, and the flatness of the bottom surface 14 is, for example, 20 μm or less.

[0093] As shown in FIG. 2B, the second bottom surface 15b is surrounded by the first bottom surface 15a in top view. In that case, it is easy to confirm where the second bottom surface 15b is located, and it is easy to arrange the mirror member 30 on the second bottom surface 15b. In the example shown in FIG. 2B, the dimension of the second bottom surface 15b in the X direction is smaller than the dimension of the first bottom surface 15a in the X direction, but the relationship between the dimensions is not limited to this example. The dimension of the second bottom surface 15b in the X direction may be the same as the dimension of the first bottom surface 15a in the X direction. The second bottom surface 15b may be provided so as to cross the recess 13 in the X direction. In that case, the second bottom surface 15b may be sandwiched between a part of the first bottom surface 15a located in the +Z direction from the second bottom surface 15b and the remaining part located in the -Z direction from the second bottom surface 15b in top view. Even in this case, it is easy to confirm the position of the second bottom surface 15b, and it is easy to place the mirror member 30 on the second bottom surface 15b. Note that the part of the first bottom surface 15a located further in the +Z direction than the second bottom surface 15b may be omitted.

[0094] In the light emitting device 110, by making the second bottom surface 15b lower than the first bottom surface 15a, the mirror member 30 can be disposed at a lower position compared to the light emitting device 100 that does not have the second bottom surface 15b. As a result, even if the thickness of the submount 21 included in the laser light source 20 is made smaller, the laser light L emitted from the semiconductor laser element 22 can be made incident on the reflection surface 32. Since the thickness of the submount 21 can be made smaller, the heat generated from the semiconductor laser element 22 during operation can be more effectively transferred to the substrate 10 via the submount 21, and the heat can be more effectively transferred to the placement surface via the substrate 10. This helps to improve the heat dissipation of the light emitting device 100.

[0095] Furthermore, in the light emitting device 110, the laser light source 20 is disposed on the first bottom surface 15a, and the mirror member 30 is disposed on the second bottom surface 15b, of the first bottom surface 15a and the second bottom surface 15b, which are planar and parallel to each other. Therefore, it is possible to reduce the deviation between the traveling direction of the laser light L emitted from the laser light source 20 and the +Z direction, and to reduce the deviation between the traveling direction of the laser light L reflected by the reflecting surface 32 and the +Y direction. As a result, it is possible to reduce the deviation between the laser light L emitted to the outside of the light emitting device 110 and the +Y direction, which is the designed traveling direction. When the first bottom surface 15a, the second bottom surface 15b, and the lower surface 14 are planar and parallel to each other, it is possible to more effectively reduce the deviation between the laser light L emitted to the outside of the light emitting device 110 and the +Y direction, which is the designed traveling direction. The effect obtained by the lower surface 14 of the substrate 10V being flat in the light emitting device 110 is the same as the effect obtained by the lower surface 14 being flat in the light emitting device 100 according to this embodiment.

[0096] (Method of manufacturing a light emitting device) A method for manufacturing the base 60 used in the light emitting device 100 according to this embodiment will be described below with reference to Figures 3A to 3C. Figures 3A to 3C are cross-sectional views parallel to the YZ plane for explaining an example of a process of the method for manufacturing the base 60 used in the light emitting device 100 according to this embodiment.

[0097] In the first step, as shown in FIG. 3A, a base body 61 is prepared in which the substrate 11 and the frame 40 are joined. The substrate 11 has an upper surface 12 and a lower surface 14. The frame 40 is located around the upper surface 12 of the substrate 11. The material of the substrate 11 is the same as that of the substrate 10 shown in FIG. 1C. The material of the frame 40 is as described above. As described above, when the substrate 11 and the frame 40 are joined via an inorganic joining member such as a brazing material, if the thermal expansion coefficient of the substrate 11 is higher than that of the frame 40, the substrate 11 tends to warp upward more convexly in the long side direction than in the short side direction due to the heat applied to the inorganic joining member, as shown in FIG. 3A.

[0098] In the next step, the base body 61 is placed in a press device 70 as shown in FIG. 3B. The press device 70 includes a stage 70a having an upper surface 72, a pressing part 70b having a lower end 74 and extending along the Y direction, and a support member 70c that supports the pressing part 70b and moves along the Y direction. The upper surface 72 of the stage 70a and the lower end 74 of the pressing part 70b are planar and parallel to the XZ plane and are parallel to each other. At least a part of the lower surface 14 of the substrate 11 of the base body 61 contacts the upper surface 72 of the stage 70a. This is because the distance in the Y direction from the upper surface 12 of the substrate 11 to the lower surface 14 of the substrate 11 is longer than the distance in the Y direction from the upper surface 12 of the substrate 11 to the first lower surface 44a of the frame 40. Here, the distance in the Y direction from the upper surface 12 of the substrate 11 to the lower surface 14 of the substrate 11 means the distance in the Y direction from the uppermost point on the upper surface 12 of the substrate 11 to the lowermost point on the lower surface 14 of the substrate 11. The distance in the Y direction from the upper surface 12 of the substrate 11 to the first lower surface 44a of the frame 40 means the distance in the Y direction from the uppermost point on the upper surface 12 of the substrate 11 to the lowermost point on the first lower surface 44a of the frame 40.

[0099] In the next step, the upper surface 12 of the substrate 11 is pressed by the lower end 74 of the pressing part 70b as shown in FIG. 3C. This pressing is performed, for example, by image-recognizing the hole of the frame 40 in a top view and aligning the center of the lower end 74 of the pressing part 70b in a bottom view with the center of the hole. As a result, a recess 13 having a bottom surface 15 is formed on the upper surface 12, and the substrate 10 is obtained. The substrate 11 shown in FIG. 3B is sandwiched between the stage 70a and the pressing part 70b to become the substrate 10 shown in FIG. 3C. The shape of the recess 13 is determined by the lower end 74 of the pressing part 71b, and the shape of the lower surface 14 of the substrate 10 is determined by the upper surface 72 of the stage 70a. By pressing, the bottom surface 15 of the recess 13 and the lower surface 14 of the substrate 10 become planar parallel to the XZ plane and parallel to each other. The flatness of bottom surface 15 of recess 13 depends on the flatness of lower end 74 of pressing portion 70b, and the flatness of lower surface 14 of substrate 10 depends on the flatness of upper surface 72 of stage 70a.

[0100] 1G, the above pressing may cause a portion of the upper surface 12 of the substrate 10 that is not in contact with the lower end 74 of the pressing portion 70b to be pushed slightly upward, resulting in a protuberance 16. The protuberance 16 improves the visibility of the shape of the recess 13, making it easier to arrange the laser light source 20 and the mirror member 30 on the bottom surface 15 of the recess 13.

[0101] The above steps allow the base 60 used in the light emitting device 100 according to this embodiment to be manufactured. In addition to the above steps of manufacturing the base 60, the manufacturing method for the light emitting device 100 according to this embodiment includes a step of arranging a laser light source 20, more specifically, a semiconductor laser element 22 via a submount 21, on the bottom surface 15 of the recess 13 as shown in FIG. 1F. The manufacturing method further includes a step of arranging a mirror member 30 on the bottom surface 15 of the recess 13 as shown in FIG. 1F. When a surface emitting semiconductor laser element that emits laser light L in the +Y direction is arranged on the bottom surface 15 instead of the laser light source 20, the step of arranging the mirror member 30 can be omitted.

[0102] The above-mentioned simple process of forming recess 13 on top surface 12 of substrate 10 using press device 70 makes bottom surface 15 of recess 13 flat. As a result, as described above, the lower surface of submount 21 is in uniform contact with bottom surface 15, so that heat generated from semiconductor laser element 22 when light emitting device 100 is driven can be effectively transferred to substrate 10 via submount 21. This helps to improve the heat dissipation of light emitting device 100.

[0103] Furthermore, the above-mentioned simple process of forming recesses 13 on upper surface 12 of substrate 10 using press device 70 makes lower surface 14 of substrate 10 flat. As a result, as described above, when light-emitting device 100 is placed on a flat placement surface, the entire lower surface 14 of substrate 10 is in uniform contact with the placement surface via the bonding member, so that heat generated from semiconductor laser element 22 during operation can be effectively transferred to the placement surface via substrate 10. This also helps to improve the heat dissipation of light-emitting device 100.

[0104] Furthermore, by arranging the laser light source 20 and the mirror member 30 on the planar bottom surface 15 of the recess 13, as described above, it is possible to reduce the deviation between the traveling direction of the laser light L emitted to the outside of the light emitting device 100 and the designed traveling direction.

[0105] Next, a method for manufacturing the base 60V used in the modified example of the light emitting device 100 according to the present embodiment will be described with reference to Figures 4A and 4B. Figures 4A and 4B are cross-sectional views parallel to the YZ plane for explaining an example of a process of the method for manufacturing the base 60V used in the modified example of the light emitting device 100 according to the present embodiment.

[0106] In a process after the base body 61 is prepared, the base body 61 is placed in a press device 70V as shown in FIG. 4A. The press device 70V includes a press device 71b instead of the press device 70b shown in FIG. 3B. The lower end 74 of the press device 71b has a first lower end 74a and a second lower end 74b. The upper surface 72 of the stage 70a is used as a height reference, and the second lower end 74b is located lower than the first lower end 74a. The upper surface 72 of the stage 70a and the first lower end 74a and the second lower end 74b of the press device 70b are planar and parallel to the XZ plane and are parallel to each other. The dimension of the second lower end 74b in the X direction is smaller than the dimension of the first lower end 74a in the X direction, and the second lower end 74b may be surrounded by the first lower end 74a in a bottom view. Alternatively, the dimension of the second lower end 74b in the X direction may be the same as the dimension of the first lower end 74a in the X direction, and the second lower end 74b may be sandwiched between a part of the first lower end 74a that is located in the +Z direction from the second lower end 74b and the remaining part that is located in the -Z direction from the second lower end 74b, when viewed from below.

[0107] In the next step, as shown in FIG. 4B, the upper surface 12 of the substrate 11 is pressed by the lower end 74 of the pressing portion 71b by the pressing device 70V. As a result, a substrate 10V having a recess 13 formed on the upper surface 12 is obtained. The shape of the recess 13 is determined by the shape of the lower end 74 of the pressing portion 71b. The bottom surface 15 of the recess 13 has a first bottom surface 15a and a second bottom surface 15b. The second bottom surface 15b is located lower than the first bottom surface 15a, with the lower surface 14 of the substrate 10V being taken as the height reference. By pressing, the first bottom surface 15a, the second bottom surface 15b of the recess 13, and the lower surface 14 of the substrate 10V become planar and parallel to the XZ plane, and are parallel to each other. The flatness of the first bottom surface 15a of the recess 13 depends on the flatness of the first lower end 74a of the pressing portion 70b, and the flatness of the second bottom surface 15b of the recess 13 depends on the flatness of the second lower end 74b of the pressing portion 70b. The flatness of the lower surface 14 of the substrate 10V depends on the flatness of the upper surface 72 of the stage 70a, similar to the flatness of the lower surface 14 of the substrate 10 shown in FIG. 3B.

[0108] The above steps allow the manufacture of the base 60V used in the modified example of the light emitting device 100 according to this embodiment. After the base 60 used in the light emitting device 100 according to this embodiment is manufactured, a part of the bottom surface 15 of the recess 13 may be pressed by another pressing part. By pressing, the bottom surface 15 has the first bottom surface 15a and the second bottom surface 15b, and thus the base 60V used in the modified example of the light emitting device 100 according to this embodiment is obtained.

[0109] The manufacturing method of the modified light emitting device 100 according to the present embodiment includes, in addition to the manufacturing step of the base 60V described above, a step of arranging a laser light source 20 on the bottom surface 15 of the recess 13, more specifically, on the first bottom surface 15a, as shown in Fig. 2A. The manufacturing method of the modified light emitting device 100 according to the present embodiment further includes a step of arranging a mirror member 30 on the bottom surface 15 of the recess 13, more specifically, on the second bottom surface 15b, as shown in Fig. 2A.

[0110] The above-mentioned simple process of forming the recess 13 on the upper surface 12 of the substrate 10 by the press device 70 provides the planar first bottom surface 15a and the second bottom surface 15b having different heights. With the lower surface 14 of the substrate 10V as the height reference, the laser light source 20 is disposed on the relatively higher first bottom surface 15a, and the mirror member 30 is disposed on the relatively lower second bottom surface 15b. As a result, as described above, the thickness of the submount 21 can be made smaller, so that the heat generated from the semiconductor laser element 22 during operation can be more effectively transferred to the substrate 10 via the submount 21. This helps to improve the heat dissipation of the light emitting device 100.

[0111] Furthermore, of the first bottom surface 15a and the second bottom surface 15b which are planar and parallel to each other, the laser light source 20 is disposed on the first bottom surface 15a, and the mirror member 30 is disposed on the second bottom surface 15b. Therefore, as described above, it is possible to reduce the deviation between the traveling direction of the laser light L emitted to the outside of the light emitting device 100 and the traveling direction in design.

[0112] The present disclosure includes light emitting devices as described in the following items. [Item 1] A substrate made of a metal material having an upper surface, the upper surface being provided with a recess having a bottom surface including a planar region; a submount disposed on the bottom surface of the recess; a semiconductor laser element disposed on the submount and configured to emit laser light; a lens support member disposed on the submount; a lens supported by the lens support member and configured to collimate or focus the laser light emitted from the semiconductor laser element; a frame body made of ceramics surrounding the semiconductor laser element; Equipped with the substrate and the semiconductor laser element are rectangular in top view, the rectangular shape having long sides and short sides; A light emitting device, wherein a long side of the substrate and a long side of the semiconductor laser element are parallel to each other. [Item 2] 2. The light emitting device according to item 1, wherein the length of a long side of the semiconductor laser element is 1500 μm or more. [Item 3] 3. The light emitting device according to item 1 or 2, wherein the recess has a rectangular shape with rounded corners when viewed from above. [Item 4] 4. The light emitting device according to any one of items 1 to 3, wherein the substrate has a planar lower surface opposite the upper surface. [Item 5] 5. The light emitting device according to any one of items 1 to 4, further comprising a mirror member disposed on the bottom surface of the recess and configured to reflect the laser light and change the traveling direction of the laser light in a direction away from the upper surface. [Item 6] 6. The light emitting device according to any one of items 1 to 5, wherein an outer edge of the recess is present inside the frame body when viewed from above. [Item 7] 7. The light emitting device according to any one of items 1 to 6, wherein the bottom surface of the recess and the lower surface of the substrate are parallel to each other. [Item 8] 8. The light emitting device according to any one of items 1 to 7, wherein a distance between the upper surface of the substrate and the bottom surface of the recess is smaller than a distance between an upper surface of the semiconductor laser element and the bottom surface of the recess. [Item 9] 9. The light emitting device according to any one of items 1 to 8, wherein a distance between the upper surface of the substrate and the bottom surface of the recess is smaller than a distance between an upper surface of the semiconductor laser element and a lower surface of the semiconductor laser element. [Item 10] the flatness of the planar region on the bottom surface of the recess is 10 μm or less; 10. The light emitting device according to any one of items 1 to 9, wherein the flatness of the lower surface of the substrate is 50 μm or less. [Item 11] the bottom surface of the recess has a first bottom surface supporting the semiconductor laser element and a second bottom surface supporting the mirror member, Item 6. The light emitting device according to item 5, wherein the second bottom surface is located lower than the first bottom surface, taking the lower surface of the substrate as a height reference. [Item 12] Item 12. The light emitting device according to item 11, wherein a distance from the upper surface of the substrate to a lower surface of the substrate is longer than a distance from the upper surface of the substrate to a lower surface of the frame. [Item 13] Item 13. The light emitting device according to item 11 or 12, wherein the first bottom surface and the second bottom surface are planar and parallel to each other. [Item 14] 11. The light emitting device according to any one of items 1 to 10, wherein a distance from the upper surface of the substrate to a lower surface of the substrate is longer than a distance from the upper surface of the substrate to a lower surface of the frame. [Item 15] The frame has an opening penetrating from an upper surface to a lower surface, the opening having a step on a lower surface side of an inner surface thereof, Item 15. The light emitting device according to any one of items 1 to 14, wherein a peripheral area of ​​the upper surface of the substrate is bonded to the step. [Item 16] Item 16. The light emitting device according to item 15, wherein the peripheral region of the upper surface of the substrate and the step are bonded via an inorganic bonding material. [Industrial Applicability]

[0113] The light emitting device of the present disclosure can be used in devices such as laser processing machines, projectors, and illumination light sources. [Explanation of symbols]

[0114] 10, 10V, 11: substrate 12: upper surface of substrate 13: recess 14: lower surface of substrate 15: bottom surface of recess 15a: first bottom surface of recess 15b: second bottom surface of recess 16: raised portion 20: laser light source 21: submount 21s1: upper surface of submount 21s2: lower surface of submount 22: semiconductor laser element 22e: emission surface 23: lens support member 23a: columnar portion 23as: end surface 23b: connecting portion 24: fast axis collimating lens 30: mirror member 32: reflecting surface 40: frame 41: wire 42a: first upper surface of frame 42b: second upper surface of frame 43: protrusion 44a: first lower surface of frame 44b: second lower surface of frame 45: opening 46a: first bonding region 46b: second bonding region 47: outer region 48a: first conductive region 48b: second conductive region 48c: third conductive region 48d: fourth conductive region 50: cover 52: upper surface of cover 54: lower surface of cover 56: light-transmitting portion 58: light-shielding film 60, 60V: base 61: base body 70, 70V: pressing device 70a: stage 70b, 71b: pressing portion 70c: support member 72: upper surface of stage 74: lower end of pressing portion 74a: first lower end of pressing portion 74b: second lower end of pressing portion 100, 110: light-emitting device L: laser light

Claims

1. A substrate made of a metal material having an upper surface, the upper surface being provided with a recess having a bottom surface including a planar region; a submount disposed on the bottom surface of the recess; a semiconductor laser element disposed on the submount and configured to emit laser light; a lens support member disposed on the submount; a lens supported by the lens support member and configured to collimate or focus the laser light emitted from the semiconductor laser element; a frame body made of ceramics surrounding the semiconductor laser element; Equipped with the substrate and the semiconductor laser element are rectangular in top view, the rectangular shape having long sides and short sides; A light emitting device, wherein a long side of the substrate and a long side of the semiconductor laser element are parallel to each other.

2. 2. The light emitting device according to claim 1, wherein the length of a long side of said semiconductor laser element is 1500 [mu]m or more.

3. The light emitting device according to claim 1 , wherein the recess has a rectangular shape with rounded corners when viewed from above.

4. 10. The light emitting device of claim 1, wherein the substrate has a planar lower surface opposite the upper surface.

5. The light emitting device according to claim 1 , further comprising a mirror member disposed on the bottom surface of the recess for reflecting the laser light and changing the traveling direction of the laser light in a direction away from the upper surface.

6. The light emitting device according to claim 1 , wherein an outer edge of the recess is present inside the frame in a top view.

7. The light emitting device according to claim 1 , wherein the bottom surface of the recess and the lower surface of the substrate are parallel to each other.

8. The light emitting device according to claim 1 , wherein a distance between the upper surface of the substrate and the bottom surface of the recess is smaller than a distance between an upper surface of the semiconductor laser element and the bottom surface of the recess.

9. 7. The light emitting device according to claim 1, wherein a distance between the upper surface of the substrate and the bottom surface of the recess is smaller than a distance between an upper surface of the semiconductor laser element and a lower surface of the semiconductor laser element.

10. the flatness of the planar region on the bottom surface of the recess is 10 μm or less; The light emitting device according to claim 1 , wherein the flatness of the lower surface of the substrate is 50 μm or less.

11. the bottom surface of the recess has a first bottom surface supporting the semiconductor laser element and a second bottom surface supporting the mirror member, The light emitting device according to claim 5 , wherein the second bottom surface is located lower than the first bottom surface, with the lower surface of the substrate being used as a reference height.

12. The light emitting device according to claim 11 , wherein a distance from the upper surface of the substrate to a lower surface of the substrate is longer than a distance from the upper surface of the substrate to a lower surface of the frame.

13. The light emitting device of claim 11 , wherein the first and second bottom surfaces are planar and parallel to each other.

14. The light emitting device according to claim 1 , wherein a distance from the upper surface of the substrate to a lower surface of the substrate is longer than a distance from the upper surface of the substrate to a lower surface of the frame.

15. The frame has an opening penetrating from an upper surface to a lower surface, the opening having a step on a lower surface side of an inner surface thereof, 7. A light emitting device according to claim 1, wherein a peripheral region of the top surface of the substrate is bonded to the step.

16. The light emitting device according to claim 15 , wherein the peripheral region of the upper surface of the substrate and the step are bonded via an inorganic bonding material.

Images