Light emitting device, package manufacturing method, and light emitting device manufacturing method

Abstract

To suppress a deviation of an optical axis of laser light emitted to the outside of a light emission device.SOLUTION: A light emission device comprises: a semiconductor laser element; a base part which has a bottom part that supports the semiconductor laser element and a side wall that surrounds the semiconductor laser element, in which the side wall has a light transmitting part that transmits laser light emitted from the semiconductor laser element and is joined to the bottom part; a cover which forms a sealing space for sealing the semiconductor laser element together with the base part; and two lead terminals which are arranged so as to penetrate the side wall and whose one end is arranged in the sealing space. The bottom part has an upper surface, a recess located between the two lead terminals in the top view is provided on the upper surface and the recess has a planar bottom surface on which the semiconductor laser element is arranged.SELECTED DRAWING: Figure 3A

Description

[Technical Field]

[0001] The present disclosure relates to a light emitting device, a method for manufacturing a package, and a method for manufacturing a light emitting device. [Background technology]

[0002] Light-emitting devices equipped with semiconductor laser elements can be used in devices such as laser processing machines, projectors, and illumination light sources. In such light-emitting devices, manufacturing errors or structural deformation during the manufacturing process can cause the optical axis of the laser light emitted to the outside to deviate from the designed optical axis. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-98190 Summary of the Invention [Problem to be solved by the invention]

[0004] It is necessary to suppress deviation of the optical axis of laser light emitted to the outside of a light emitting device. [Means for solving the problem]

[0005] In one embodiment, the light-emitting device of the present disclosure includes: a semiconductor laser element; a base having a bottom supporting the semiconductor laser element and sidewalls surrounding the semiconductor laser element, the sidewalls having a light-transmitting portion that transmits laser light emitted from the semiconductor laser element and joined to the bottom; a cover that, together with the base, forms a sealed space that seals the semiconductor laser element; and two lead terminals that are disposed to penetrate the sidewalls and have one end each disposed inside the sealed space, the bottom having an upper surface that is provided with a recess located between the two lead terminals in a top view, and the recess having a planar bottom surface on which the semiconductor laser element is disposed.

[0006] In one embodiment, a method for manufacturing a package according to the present disclosure includes the steps of: preparing a package body having a base having a bottom and side walls that form a space for accommodating a semiconductor laser element; and two lead terminals that are disposed so as to penetrate the side walls and each have one end disposed within the space; and pressing a predetermined area on an upper surface of the bottom between the two lead terminals using a press device to form a recess with a flat bottom on the upper surface of the bottom.

[0007] In one embodiment, a method for manufacturing a light emitting device according to the present disclosure includes the steps of manufacturing a package by the package manufacturing method, and arranging the semiconductor laser element on the bottom surface of the recess. [Effects of the Invention]

[0008] According to the embodiment of the present disclosure, it is possible to suppress deviation of the optical axis of laser light emitted to the outside of the light emitting device. [Brief explanation of the drawings]

[0009] [Figure 1A] FIG. 1A is a front perspective view schematically illustrating the configuration of a light emitting device according to an exemplary embodiment of the present disclosure. [Figure 1B] FIG. 1B is a rear perspective view schematically illustrating the configuration of a light emitting device according to an exemplary embodiment of the present disclosure. [Figure 1C] FIG. 1C is a top view schematically showing the internal configuration of the light emitting device of FIG. 1A. [Figure 1D] FIG. 1D is a cross-sectional perspective view parallel to the YZ plane, schematically showing the base, the lead terminal, and the lead holding member. [Figure 2A] FIG. 2A is an exploded perspective view schematically showing the configuration of a laser light source. [Figure 2B] FIG. 2B is a cross-sectional view of the laser light source shown in FIG. 2A, taken parallel to the YZ plane. [Figure 3A]FIG. 3A is a cross-sectional view of the light emitting device shown in FIG. 1A, taken along a plane parallel to the YZ plane. [Figure 3B] FIG. 3B is a cross-sectional view of the light-emitting device shown in FIG. 1A, taken along a plane parallel to the XY plane. [Figure 3C] FIG. 3C is an enlarged view of the area enclosed by the dashed line shown in FIG. 3B. [Figure 4A] FIG. 4A is a diagram for explaining an example of a process in a method for manufacturing a package for a light emitting device according to this embodiment. [Figure 4B] FIG. 4B is a diagram for explaining an example of a process in the method for manufacturing a package for a light emitting device according to this embodiment. [Figure 4C] FIG. 4C is a diagram for explaining an example of a step in the method for manufacturing a package for a light emitting device according to this embodiment. [Figure 5A] FIG. 5A is a graph showing the relationship between the deviation angle (horizontal axis) of the optical axis of the laser light emitted from the laser light source before accommodation and the deviation angle (vertical axis) of the optical axis of the laser light emitted from the light emitting device that accommodates the laser light source for the comparative example. [Figure 5B] Figure 5B is a graph showing the relationship between the deviation angle (horizontal axis) of the optical axis of the laser light emitted from the laser light source before accommodation and the deviation angle (vertical axis) of the optical axis of the laser light emitted from the light-emitting device that accommodates the laser light source for the example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a light emitting device, a method for manufacturing a package, and a method for manufacturing a light emitting device according to embodiments of the present disclosure 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.

[0011] Furthermore, the embodiments described below are examples to embody the technical idea of ​​the present invention, and do not limit the present invention. Furthermore, the size, material, shape, relative arrangement, etc. of components are intended to be illustrative and not to limit the scope of the present invention. The size and positional relationship of components shown in each drawing may be exaggerated to facilitate understanding.

[0012] (Embodiment) A basic configuration example of a light-emitting device according to an embodiment of the present disclosure will be described with reference to FIGS. 1A to 1D. FIGS. 1A and 1B are front and rear perspective views, respectively, that schematically illustrate the configuration of a light-emitting device according to an exemplary embodiment of the present disclosure. For reference, these figures schematically illustrate mutually orthogonal X, Y, and Z axes. 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. For ease of explanation, the +Y direction will be referred to as "upward" and the −Y direction will be referred to as "downward" in this specification. This does not limit the orientation of the light-emitting device during use, and the light-emitting device may be oriented in any direction.

[0013] The light-emitting device 100 shown in FIG. 1A includes a semiconductor laser element and a base 50 that houses the semiconductor laser element. The semiconductor laser element is not visible from the outside. The light-emitting device 100 also includes two lead terminals 60 that supply power to the semiconductor laser element, a lead holding member 70 that holds the two lead terminals 60, and a cover 80 fixed to the base 50. The cover 80, together with the base 50, forms a sealed space that seals the semiconductor laser element. This sealing is preferably airtight. The effect of airtight sealing increases as the wavelength of the laser light emitted from the semiconductor laser element becomes shorter. This is because, in a configuration where the emission surface of the semiconductor laser element is exposed to the outside air without airtight sealing, the shorter the wavelength of the laser light, the more likely it is that the emission surface will deteriorate during operation due to dust collection.

[0014] The base 50 has a bottom 50b that supports the semiconductor laser element and a sidewall 50w that surrounds the semiconductor laser element. The sidewall 50w is joined to the bottom 50b. The sidewall 50w further has a light-transmitting portion 50t that transmits laser light emitted from the semiconductor laser element. The light-emitting device 100 emits laser light from the light-transmitting portion 50t in the +Z direction. The sidewall 50w has a portion that extends along the Y direction. The maximum dimension (height) of the sidewall 50w in the Y direction can be, for example, 0.2 to 0.5 times the perimeter of the outer periphery of the sidewall 50w.

[0015] FIG. 1C is a top view schematically showing the internal configuration of the light emitting device 100 of FIG. 1A. In FIG. 1C, the cover 80 is not shown. As shown in FIG. 1C, the light emitting device 100 includes, inside a base 50, a submount 10, a semiconductor laser element 20 and a lens support member 30 supported by the submount 10, and a lens 40 supported by the lens support member 30. In the following description, a configuration including the submount 10, the semiconductor laser element 20, the lens support member 30, and the lens 40 will be referred to as a "laser light source 100A." The laser light source 100A is a chip-on-submount type semiconductor laser light source. The detailed configuration of the laser light source 100A will be described later.

[0016] The light emitting device 100 further includes a plurality of wires 60w inside the base 50. Some of the plurality of wires 60w are electrically connected to one lead terminal 60 and the semiconductor laser element 20, and the remaining portion is electrically connected to the other lead terminal 60 and the semiconductor laser element 20. The plurality of wires 60w are used to supply power from the two lead terminals 60 to the semiconductor laser element 20. In the example shown in FIG. 1C, the number of laser light sources 100A is one, but may be two or more.

[0017] FIG. 1D is a cross-sectional perspective view, parallel to the YZ plane, of the base 50, lead terminals 60, and lead holding member 70. The sidewall 50w of the base 50 includes a circular opening 50о and a ring-shaped cap 50c supported by the periphery of the opening 50о. The cap 50c holds the light-transmitting portion 50t by its inner periphery. The periphery of the cap 50c and the light-transmitting portion 50t are joined by a ring-shaped joining member 50g. Laser light emitted from the laser light source 100A shown in FIG. 1C passes through the hollow portions of the cap 50c and the joining member 50g and penetrates the light-transmitting portion 50t. The sidewall 50w further includes two through-holes 50h through which the two lead terminals 60 pass, respectively. A reinforcing member 52 is provided on the upper surface of the sidewall 50w. The reinforcing member 52 improves the sealing performance of the cover 80 shown in FIG. 1A.

[0018] The bottom 50b of the base 50 includes a flat portion 50b1 and a convex portion 50b2 that supports the laser light source 100A. The sidewall 50w is joined to a peripheral portion 50bp of the flat portion 50b1. The bottom 50b has an upper surface 50bs1 and a lower surface 50bs2. The upper surface 50bs1 of the bottom 50b is the upper surface of the convex portion 50b2, and the lower surface 50bs2 of the bottom 50b is the lower surface of the flat portion 50b1. The lower surface 50bs2 of the bottom 50b is also the lower surface of the base 50. The convex portion 50b2 forms a step with the flat portion 50b1. More specifically, the step is formed between the upper surface 50bs1 of the convex portion 50b2 and the peripheral portion 50bp of the flat portion 50b1. The dimension of the step in the Y direction may be 0.25 to 0.5 times the height of the sidewall 50w. By supporting the laser light source 100A with the convex portion 50b2, the portion of the laser light source 100A from which the laser light is emitted can be made to face the light-transmitting portion 50t. As a result, the laser light emitted from the laser light source 100A is emitted to the outside through the light-transmitting portion 50t. In this specification, a view from the normal direction (Y direction) of the top surface 50bs1 of the bottom portion 50b is referred to as a "top view."

[0019] The bottom portion 50b is formed from a plastic material such as metal, and its shape can be partially deformed using a press. The press may include, for example, a stage with a flat support surface and a pressing unit with a flat lower end. The lower end of the pressing unit can be adjusted to be parallel to the support surface of the stage. The base 50 is placed on the stage of such a press with the bottom portion 50b facing downwards, and a predetermined region of the upper surface 50bs1 of the bottom portion 50b is pressed by the pressing unit from between the two lead terminals 60, thereby forming a recess 50b3 in the upper surface 50bs1 of the bottom portion 50b.

[0020] In a configuration before the recess 50b3 is provided, when the sidewall 50w is joined to the bottom 50b, the portion of the bottom 50b that is joined to the sidewall 50w may be pulled by the sidewall 50w, causing the bottom 50b to deform and form a downwardly convex curved lower surface 50bs2. Even if such deformation does not occur, the upper surface 50bs1 and the lower surface 50bs2 of the bottom 50b may not be parallel to each other due to manufacturing errors of the bottom 50b. Therefore, if the laser light source 100A is placed on the upper surface 50bs1 of the bottom 50b without the recess 50b3, there is a problem in that the optical axis of the laser light emitted from the laser light source 100A deviates from the designed optical axis. In this specification, "the optical axis of the laser light deviates from the designed optical axis" means that the optical axis direction of the laser light is not parallel to the designed optical axis direction.

[0021] In contrast, in the light emitting device 100 according to this embodiment, a recess 50b3 is formed in the upper surface 50bs1 of the bottom portion 50b using a press machine, the recess 50b3 being located between the two lead terminals 60 in a top view. The recess 50b3 has a planar bottom surface on which the laser light source 100A is disposed. Furthermore, the lower surface 50bs2 of the bottom portion 50b is deformed to become planar when the recess 50b3 is formed in the upper surface 50bs1 of the bottom portion 50b using the press machine. The bottom surface of the recess 50b3 is parallel to the lower surface 50bs2 of the bottom portion 50b. The flatness of each of the bottom surface of the recess 50b3 and the lower surface 50bs2 of the bottom portion 50b can be, for example, 1 mm or less.

[0022] According to JIS 0621-1984, for example, flatness is defined as the deviation of a planar feature from a geometrically correct plane (hereinafter referred to as a "geometric plane"). Flatness is the size of the gap that occurs between two geometric planes that are strictly parallel to each other when an object is sandwiched between the two geometric planes. Flatness can be measured, for example, using a three-dimensional measuring machine. In this specification, two planes being parallel to each other does not only mean that the two planes are strictly parallel, but also means that the absolute value of the angle between the two planes is 0.5° or less.

[0023] Here, we will take as an example a configuration in which the light emitting device 100 is mounted on a mounting surface parallel to the XZ plane, and the front surface of the light emitting device 100 faces the +Z direction. In this configuration, the lower surface 50bs2 of the bottom 50b is parallel to the mounting surface, and the laser light source 100A is disposed on the bottom surface of the recess 50b3. In this configuration, since the bottom surface of the recess 50b3 is parallel to the lower surface 50bs2 of the bottom 50b, the optical axis direction of the laser light emitted from the laser light source 100A can be made parallel to the +Z direction, which is the designed optical axis direction. As described above, the light emitting device 100 according to this embodiment can suppress deviation of the optical axis of the laser light emitted to the outside. In this specification, the optical axis direction of the laser light being parallel to the designed optical axis direction means not only when both directions are strictly parallel, i.e., strictly the same direction, but also when the absolute value of the angle between the two directions is 0.5° or less.

[0024] The two lead terminals 60 and the lead holding member 70 are arranged as follows: The two lead terminals 60 are arranged to penetrate the side wall 50w. One end of each lead terminal 60 is located inside the sealed space. The lead holding member 70 is provided on the back surface of the base 50 and holds the two lead terminals 60. The lead holding member 70 has two through holes 70h through which the two lead terminals 60 pass, and two bonding members 72 that each fill the gap between the through holes 70h and the lead terminals 60. The lead holding member 70 helps maintain the sealed space even when the side wall 50w thermally expands when the light emitting device 100 is driven. If thermal expansion is not a problem, the two lead terminals 60 may be held by the two through holes 50h in the side wall 50w without using the lead holding member 70.

[0025] The configuration of the laser light source 100A housed in the light emitting device 100 shown in FIG. 1C will be described below with reference to FIGS. 2A and 2B. FIG. 2A is an exploded perspective view schematically showing the configuration of the laser light source 100A. The laser light source 100A shown in FIG. 2A includes a submount 10, an edge-emitting semiconductor laser element 20, a lens support member 30, and a lens 40. In FIG. 2A, the lens support member 30 and the lens 40 are shown in a separated state, but in reality, the two are joined together. FIG. 2B is a cross-sectional view parallel to the YZ plane of the laser light source 100A shown in FIG. 2A.

[0026] As shown in FIG. 2A , the submount 10 has an upper surface 10s1 and a lower surface 10s2 parallel to the XZ plane. A first metal film 10m1 is provided on the upper surface 10s1 of the submount 10, and a second metal film 10m2 is provided on the lower surface 10s2. The first metal film 10m1 improves the bonding strength when the semiconductor laser element 20 and the lens support member 30 are bonded to the upper surface 10s1 of the submount 10 with an inorganic bonding material. The inorganic bonding material may be, for example, a solder material such as gold-tin, or a sintered material such as a metal paste containing multiple metal particles and an organic binder. The electrically conductive first metal film 10m1 can also be used to supply power to the semiconductor laser element 20. Furthermore, the first metal film 10m1 improves thermal conductivity, thereby helping to dissipate heat generated when the semiconductor laser element 20 is driven. The second metal film 10m2 improves the bonding strength when the laser light source 100A is bonded to the bottom surface of the recess 50b3 shown in Fig. 1D with an inorganic bonding material. The inorganic bonding material may be, for example, the above-mentioned solder material or sintered material.

[0027] As shown in FIG. 2A, the semiconductor laser element 20 is supported by the upper surface 10s1 of the submount 10 via a first metal film 10m1. The semiconductor laser element 20 has an emission surface 20e, one of two end surfaces intersecting the Z direction, and emits laser light in the Z direction from the emission surface 20e. 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.

[0028] As shown in FIG. 2A , the lens support member 30 is supported by the upper surface 10s1 of the submount 10 via a first metal film 10m1. The lens support member 30 has two columnar portions 30p and a connecting portion 30L located between the two columnar portions 30p and connecting the two columnar portions 30p. The two columnar portions 30p are located on both sides of the semiconductor laser element 20, and the connecting portion 30L is located above the semiconductor laser element 20. The lens support member 30 supports the lens 40 by end faces 30s1 of the two columnar portions 30p. The lens support member 30 is located so as to straddle the semiconductor laser element 20 and does not prevent laser light emitted from the semiconductor laser element 20 from entering the lens 40.

[0029] The bottom surface of the semiconductor laser element 20 is at the same position as or higher than the bottom surfaces of the two columnar portions 30p in the Y direction. The top surface of the semiconductor laser element 20 is at a position lower than the top surfaces of the two columnar portions 30p and lower than the bottom surface of the connecting portion 30L in the Y direction. When viewed from the +Z direction side, the emission surface 20e of the semiconductor laser element 20 is at a position higher than the bottom sides of the end faces 30s1 of the two columnar portions 30p, lower than the top sides of the end faces 30s1, and lower than the bottom side of the end face 30s2 of the connecting portion 30L in the Y direction.

[0030] As shown in FIG. 2A, the lens 40 is a cylindrical lens extending along the X direction. The lens 40 has a flat surface on the light incident side and a convex surface on the light emitting side. The convex surface has a curvature in the YZ plane. The focal point of the lens 40 coincides with the center of the light emitting point on the emission surface 20e of the semiconductor laser element 20. The coincidence of the focal point of the lens 40 with the center of the emission surface 20e means not only that they exactly coincide with each other, but also that the deviation between them is 1 μm or less. As shown in FIG. 2B, the lens 40 collimates the laser light 20L emitted in the +Z direction from the emission surface 20e of the semiconductor laser element 20 in the YZ plane. The area surrounded by the dashed line in FIG. 2B is a region where the intensity of the laser light 20L is 1 / e of its peak intensity. 2 represents the area where the number is equal to or greater than the number of times the number of times of the original number. e is the base of the natural logarithm.

[0031] Since the lens 40 is disposed inside the sealed space, it can collimate the laser light 20L before it spreads too much. This allows the lens 40 to be made compact. In the example shown in FIG. 2B, the direction of the optical axis (dashed line) of the laser light 20L is parallel to the +Z direction, which is the designed optical axis direction. In this specification, collimation includes not only collimating the laser light 20L but also reducing the spread of the laser light 20L.

[0032] The convex curved surface on the light-emitting side of lens 40 may have curvature not only in the YZ plane but also in the XZ plane. Lens 40 having such a convex curved surface collimates laser light 20L not only in the YZ plane but also in the XZ plane. Note that as long as the portion of the light-emitting side surface of lens 40 from which laser light 20L is emitted has curvature, other portions of lens 40 may or may not have curvature. Lens 40 may be a focusing lens that focuses laser light.

[0033] At least a portion of the end faces 30s1 of the two columnar portions 30p of the lens support member 30 and a surface of the lens 40 facing the at least a portion of the end face 30s1 are bonded to each other with an inorganic bonding material. By providing a metal film on at least a portion of the end face 30s1 of the lens support member 30 and a metal film on the surface of the lens 40 facing the at least a portion of the end face 30s1, it is possible to improve the bonding strength between the lens support member 30 and the lens 40. If the inorganic bonding material is a metal paste, when bonding the lens 40 to the lens support member 30, the lens 40 can be adjusted to a position where the laser light 20L can be collimated.

[0034] The center of gravity of the lens 40 is located between the end faces 30s1 of the two columnar portions 30p in the X direction when viewed from the +Z direction. Furthermore, the center of gravity of the lens 40 is located at the same position as or higher than the lower edges of the end faces 30s1 of the two columnar portions 30p and lower than the upper edges when viewed from the +Z direction. By locating the center of gravity of the lens 40 in such a position, the lens 40 can be stably fixed to the lens support member 30.

[0035] Next, with reference to Figures 3A to 3C, we will explain how the laser light source 100A shown in Figure 2A is arranged on the bottom portion 50b. Figures 3A and 3B are cross-sectional views parallel to the YZ plane and the XY plane, respectively, of the light-emitting device 100 shown in Figure 1A. Figure 3C is an enlarged view of the area surrounded by the dashed line in Figure 3B.

[0036] As shown in FIGS. 3A and 3B, the laser light source 100A is provided on the bottom surface of the recess 50b3. Specifically, the second metal film 10m2 provided on the submount 10 shown in FIG. 2A and the bottom surface of the recess 50b3 are bonded to each other with an inorganic bonding material. The inorganic bonding material may be, for example, a solder material or a sintered material. As described above, with the light-emitting device 100 according to this embodiment, as shown in FIG. 3A, the optical axis direction of the laser light 20L emitted from the laser light source 100A to the outside through the light-transmitting portion 50t can be made parallel to the +Z direction, which is the designed optical axis direction.

[0037] 3C, the dimension in the X direction (width wm) of the second metal film 10m2 is equal to or smaller than the dimension in the X direction (width wc) of the recess 50b3, and the dimension in the Y direction (thickness t) of the second metal film 10m2 is greater than the dimension in the Y direction (depth d) of the recess 50b3. Therefore, even if the laser light source 100A is provided on the bottom surface of the recess 50b3, the submount 10 does not come into contact with the protruding portion 50b2. The depth d of the recess 50b3 may be, for example, 0.01 to 0.1 times the dimension in the Y direction of the protruding portion 50b2.

[0038] The dimension in the X direction (width ws) of the submount 10 is larger than the width wc of the recess 50b3. Because the submount 10 does not contact the protruding portion 50b2, it is not necessary to reduce the width ws of the submount 10 to match the width wc of the recess 50b3. Therefore, compared to a configuration in which the width ws of the submount 10 is smaller than the width wc of the recess 50b3, heat generated in the semiconductor laser element 20 can be efficiently conducted to the protruding portion 50b2 via the submount 10.

[0039] On the other hand, the width ws of the submount 10 is smaller than the dimension dL of the gap between the two lead terminals 60. Therefore, the laser light source 100A can be placed on the convex portion 50b2 through the gap between the two lead terminals 60. The direction in which the two lead terminals 60 are spaced apart is parallel to the X direction.

[0040] Next, an example of a method for manufacturing a package for the light emitting device 100 according to this embodiment will be described with reference to FIGS. 4A to 4C. In this specification, the structure that seals the laser light source 100A shown in FIG. 2A is referred to as a "package." In the example shown in FIGS. 1A to 1D, the package includes a base 50, two lead terminals 60, a lead holding member 70, and a cover 80. The structure of the package excluding the cover 80 is also referred to as a "package body."

[0041] 4A to 4C are diagrams illustrating an example of steps in a manufacturing method for a package of the light-emitting device 100 according to this embodiment. In the first step, as shown in FIG. 4A, a package body is prepared. The package body includes a base 50a having a bottom 50ba and sidewalls 50w, two lead terminals 60, and a lead holding member 70. FIG. 4A shows a cross-sectional perspective view of the package body parallel to the YZ plane. The bottom 50ba and sidewalls 50w form a space for accommodating the laser light source 100A shown in FIG. 2A. The bottom 50ba includes a flat portion 50b1 and a convex portion 50b2, but does not include a concave portion. As described above, when the sidewalls 50w are joined to the bottom 50ba, the bottom 50ba may deform, causing the lower surface 50bs2 to become a downwardly convex curved surface. Furthermore, due to manufacturing errors, the upper surface 50bs1 and the lower surface 50bs2 of the bottom 50ba may not be parallel to each other.

[0042] In the next step, the package shown in FIG. 4A is placed in a press device 90 as shown in FIG. 4B. FIG. 4B shows a cross-sectional view of the package body and the press device 90, parallel to the XY plane. The press device 90 includes a stage 92 having an upper surface 92s, a pressing unit 94 having a lower end 94s and extending along the Y direction, and a support member 96 that supports the pressing unit 94 and moves along the Y direction. The upper surface 92s of the stage 92 and the lower end 94s of the pressing unit 94 are planar and parallel to each other. The upper surface 92s of the stage 92 and the lower end 94s of the pressing unit 94 are parallel to the XZ plane. The lower surface 50bs2 of the bottom portion 50ba of the package body is supported by the upper surface 92s of the stage 92. A recess is formed in a predetermined region 50b4 of the upper surface 50bs1 of the bottom portion 50ba, located between the two lead terminals 60 in a top view.

[0043] In the next step, as shown in Fig. 4C, a press device 90 presses the predetermined region 50b4 shown in Fig. 4B with the lower end 94s of a pressing portion 94 from between the two lead terminals 60, thereby obtaining a bottom portion 50b having a recess 50b3 formed in the upper surface 50bs1. The press device 90 makes the lower surface 50bs2 of the bottom portion 50b and the bottom surface of the recess 50b3 flat and parallel to each other.

[0044] Through the above steps, a package for the light emitting device 100 according to this embodiment can be manufactured. As described above, the simple process of forming the recess 50b3 on the upper surface 50bs1 of the bottom 50b using the press device 90 can suppress deviation of the optical axis of the laser light emitted to the outside from the light emitting device 100.

[0045] The method for manufacturing the light emitting device 100 according to this embodiment includes, in addition to the above-described package manufacturing process, a process of arranging the laser light source 100A shown in Fig. 2A on the bottom surface of the recess 50b3. In the light emitting device 100, the semiconductor laser element 20 is arranged on the bottom surface of the recess 50b3 via the submount 10, the first metal film 10m1, and the second metal film 10m2.

[0046] Next, with reference to FIGS. 5A and 5B and Table 1, examples and comparative examples of the light emitting device 100 according to this embodiment will be described. The light emitting device according to the example has a configuration in which a laser light source is housed in a package as shown in FIG. 1D. On the other hand, the light emitting device according to the comparative example has a configuration in which a laser light source is housed in a package as shown in FIG. 4A. In each of the example and comparative example, the deviation angle Δθ1 between the optical axis of the laser light emitted from the laser light source before housing and the designed optical axis was investigated. Furthermore, in each of the example and comparative example, the deviation angle Δθ2 between the optical axis of the laser light emitted from the light emitting device housing the laser light source and the designed optical axis was investigated.

[0047] 5A and 5B are graphs showing the relationship between the deviation angle Δθ1 of the optical axis of the laser light emitted from the laser light source before installation and the deviation angle Δθ2 of the optical axis of the laser light emitted from the light-emitting device that houses the laser light source, respectively, for the comparative example and the example. Positive and negative values ​​of the deviation angles Δθ1 and Δθ2 indicate that the optical axis of the laser light is tilted upward and downward, respectively, with respect to the designed optical axis. The range between the dashed lines in FIGS. 5A and 5B represents an example of the allowable range of the deviation angles Δθ1 and Δθ2. This allowable range is between -0.1° and 0.1°. The number of samples for the comparative example shown in FIG. 5A was 648, and the number of samples for the example shown in FIG. 5B was 31.

[0048] In the comparative example shown in Fig. 5A, the percentage of samples whose deviation angle Δθ1 was within the allowable range was high, while the percentage of samples whose deviation angle Δθ2 was within the allowable range was significantly low. In contrast, in the example shown in Fig. 5B, the percentage of samples whose deviation angle Δθ1 was within the allowable range was 100%, and the percentage of samples whose deviation angle Δθ2 was within the allowable range was also extremely high.

[0049] Table 1 shows, as examples, the number of samples of laser light sources and light-emitting devices, the standard deviation, maximum value, and minimum value of the deviation angle of the laser light emitted from the laser light source and light-emitting device, and the yield of the laser light source and light-emitting device for the comparative example and the example. The above-mentioned tolerance range was used to calculate the yield.

[0050] [Table 1]

[0051] According to the comparative example, in the light emitting device housing the laser light source, the standard deviation of the deviation angle of the laser light was 5.72 times, the maximum deviation angle was 7.28 times, and the minimum deviation angle was 2.88 times, compared to the laser light source before housing, as shown in Table 1. The yield of the laser light source before housing was 93.4%, while the yield of the light emitting device housing the laser light source was 48.8%, which was significantly lower.

[0052] In contrast, according to the example, as shown in Table 1, in the light emitting device housing the laser light source, the standard deviation of the deviation angle of the laser light was 2.13 times, the maximum deviation angle was 2.88 times, and the minimum deviation angle was 2.20 times, compared to the laser light source before housing. In the example, the deviation of the optical axis did not worsen as much as in the comparative example. As a result, the yield of the laser light source before housing was 100%, and the yield of the light emitting device housing the laser light source also remained high at 96.8%.

[0053] From the above, it is confirmed that the light emitting device 100 according to this embodiment can effectively suppress deviation of the optical axis of the laser light emitted to the outside.

[0054] Furthermore, in the light emitting device 100 according to this embodiment, as will be described later, the lead terminals 60 are capable of passing a large current, and the lead holding member 70 is capable of improving the durability of the package against thermal stress. Therefore, the light emitting device 100 according to this embodiment can emit high-power laser light, for example, of 10 W or more.

[0055] The light-emitting device 100 according to this embodiment, which can suppress deviation of the optical axis of the laser beam and emit high-power laser beam, can be used, for example, in a laser processing machine for metal processing. The laser processing machine includes a plurality of light-emitting devices 100 arranged in one direction on a heat sink, and a focusing lens that focuses the laser beams emitted from the plurality of light-emitting devices 100. Since the deviation of the optical axis of the laser beams emitted from the light-emitting devices 100 is small, the high-power laser beams emitted from the plurality of light-emitting devices 100 can be focused with high precision by the focusing lens.

[0056] When the laser light emitted from each light-emitting device 100 has a short wavelength, the metal has a high light absorption rate at short wavelengths, so the metal can be efficiently processed using the focused laser light. When the metal is copper, the wavelength of the laser light emitted from each light-emitting device 100 can be, for example, 420 nm or more and 450 nm or less, and the output can be, for example, 10 W or more. The light-emitting device 100 according to this embodiment can be used in a projector or an illumination light source in addition to a laser processing machine.

[0057] The shape, material, dimensions, and other details of each component of the light emitting device 100 according to this embodiment will be described below.

[0058] [Submount 10] The submount 10 may have, for example, a rectangular parallelepiped shape. The size of the submount 10 is smallest in the vertical direction (Y direction). The shape of the submount 10 is not limited to a rectangular parallelepiped. The submount 10 may be made of, for example, at least one of silicon nitride, aluminum nitride, and silicon carbide.

[0059] The submount 10 transfers heat generated from the semiconductor laser element 20 to the bottom portion 50b. The submount 10 also serves to adjust the height of the optical axis of the laser light emitted from the semiconductor laser element 20.

[0060] The dimension of the submount 10 in the X direction may be, for example, 300 μm to 4 mm, the dimension in the Y direction may be, for example, 100 μm to 500 μm, and the dimension in the Z direction may be, for example, 200 μm to 4 mm.

[0061] A first metal film 10m1 and a second metal film 10m2 are provided on the upper surface 10s1 and the lower surface 10s2, respectively, of the submount 10. Each of the first metal film 10m1 and the second metal film 10m2 may be formed of at least one metal selected from the group consisting of, for example, Ti, Pt, Cu, and Au.

[0062] The dimensions of each of the first metal film 10m1 and the second metal film 10m2 in the X direction may be, for example, 200 μm or more and 3.95 mm or less, the dimensions in the Y direction may be, for example, 10 μm or more and 500 μm or less, and the dimensions in the Z direction may be, for example, 100 μm or more and 3.95 mm or less.

[0063] [Semiconductor laser element 20] The semiconductor laser element 20 may have, for example, a rectangular parallelepiped shape. The dimension of the semiconductor laser element 20 in the X direction is, for example, 50 μm to 500 μm, and preferably 150 μm to 500 μm. The dimension in the Y direction is, for example, 20 μm to 150 μm. The dimension in the Z direction may be, for example, 50 μm to 10 mm, and preferably 1.2 mm to 4 mm.

[0064] The semiconductor laser element 20 can emit violet, blue, green, or red laser light in the visible region, or infrared or ultraviolet laser light in the invisible region. The peak wavelength of the violet light is preferably in the range of 380 nm to 419 nm, and more preferably in the range of 400 nm to 415 nm. The peak wavelength of the blue light is preferably in the range of 420 nm to 494 nm, and more preferably in the range of 440 nm to 475 nm. The peak wavelength of the green light is preferably in the range of 495 nm to 570 nm, and more preferably in the range of 510 nm to 550 nm. The peak wavelength of the red light is preferably in the range of 605 nm to 750 nm, and more preferably in the range of 610 nm to 700 nm.

[0065] Examples of semiconductor laser elements that emit violet, blue, or green laser light include semiconductor laser elements containing GaN-based, InGaN-based, and AlGaN-based nitride semiconductor materials. Examples of semiconductor laser elements that emit red laser light include semiconductor laser elements containing InAlGaP-based, GaInP-based, GaAs-based, and AlGaAs-based semiconductor materials.

[0066] The semiconductor laser device 20 has a semiconductor multilayer structure in which a substrate, a first cladding layer, an emission layer, and a second cladding layer are stacked in this order along the +Y or −Y direction. The first cladding layer has one of p-type and n-type conductivity, and the second cladding layer has the other of p-type and n-type conductivity. The substrate is, for example, a semiconductor substrate. The semiconductor multilayer structure does not necessarily have a substrate. The semiconductor multilayer structure includes a first electrode electrically connected to the first cladding layer and a second electrode electrically connected to the second cladding layer. By applying a forward voltage to the first and second electrodes to pass a current equal to or greater than a threshold through the semiconductor multilayer structure, laser light is emitted from one of two end faces of the emission layer intersecting the Z direction, i.e., the emission surface 20e. The output power of the laser light 20L increases with increasing injection current. The output power of the laser light 20L may be, for example, 10 W or more, or less than 10 W.

[0067] The semiconductor laser element 20 may be mounted in a so-called face-up state, in which the substrate is closer to the submount 10 than the light-emitting layer in the semiconductor laminate structure. Alternatively, the semiconductor laser element 20 may be mounted in a so-called face-down state, in which the light-emitting layer is closer to the submount 10 than the substrate in the semiconductor laminate structure. Regardless of the wavelength of the laser light 20L, mounting in a face-down state allows heat generated from the semiconductor laser element 20 to be transferred to the submount 10 more efficiently than mounting in a face-up state. When mounted in a face-down state, the semiconductor laser element 20 may be disposed on the submount 10 so that a tip portion including the emission surface 20e of the semiconductor laser element 20 protrudes from the submount 10 in a top view. Such an arrangement can prevent the submount 10 from blocking part of the laser light 20L.

[0068] [Lens support member 30] The lens support member 30 may have a shape that straddles the semiconductor laser element 20, for example. The material of the lens support member 30 may be the same as that of the submount 10, for example. Alternatively, the material of the lens support member 30 may be the same light-transmitting material as that of the lens 40, which will be described later. The dimension of the lens support member 30 in the X direction may be, for example, not less than 300 μm and not more than 4 mm, the maximum dimension in the Y direction may be, for example, not less than 500 μm and not more than 2 mm, and the dimension in the Z direction may be, for example, not less than 500 μm and not more than 1 mm.

[0069] [Lens 40] Lens 40 may have, for example, a generally semi-cylindrical shape. Lens 40 may be formed from, for example, at least one light-transmitting material selected from the group consisting of glass, silicon, quartz, synthetic quartz, sapphire, transparent ceramic, and plastic. The light transmittance of the light-transmitting material may be, for example, 60% or more, preferably 70% or more, and more preferably 80% or more, with respect to the laser light 20L emitted from semiconductor laser element 20.

[0070] The dimension of lens 40 in the X direction may be equal to the dimension of lens support member 30 in the X direction, or may be larger or smaller than the dimension of lens support member 30 in the X direction. The same applies to the dimension of lens 40 in the Y direction. The dimension of lens 40 in the Z direction may be, for example, 1 mm or more and 6 mm or less.

[0071] [Base 50] The sidewall 50w of the base 50 may have, for example, a generally rectangular cylindrical shape. The sidewall 50w may also have a cylindrical or elliptical cylindrical shape. As shown in FIG. 1D , the sidewall 50w is bonded to the peripheral edge 50bp of the flat portion 50b1 of the bottom 50b with an inorganic bonding material. The inorganic bonding material may be, for example, a brazing material such as silver solder.

[0072] 1D, the sidewall 50w has the light-transmitting portion 50t via the cap 50c, so that thermal stress generated in the sidewall 50w is less likely to be transmitted to the light-transmitting portion 50t, preventing the light-transmitting portion 50t from being damaged or destroyed. A gap exists between the through-hole 50h in the sidewall 50w and the lead terminal 60, so the sidewall 50w and the lead terminal 60 do not contact each other. Therefore, even if the sidewall 50w is conductive, the two lead terminals 60 will not be short-circuited through the sidewall 50w.

[0073] The side wall 50w may be formed, for example, from kovar or SPC (steel plate cold). Kovar is an alloy of iron, the main component, with nickel and cobalt added. The thermal expansion coefficient of kovar at room temperature is relatively low among metals and is close to that of hard glass. The cap 50c may be formed, for example, from an Fe-Ni alloy. The joining member 50g may be formed, for example, from low-melting-point glass. The light-transmitting portion 50t may be formed, for example, from borosilicate glass.

[0074] The dimensions of the side wall 50w in each of the X, Y, and Z directions may be, for example, 5 mm or more and 10 mm or less.

[0075] As shown in FIG. 1D , the bottom 50b of the base 50 has a flat portion 50b1 and a convex portion 50b2. Each of the flat portion 50b1 and the convex portion 50b2 may have, for example, a rectangular parallelepiped shape. When the light emitting device 100 is placed on a heat sink, the flat portion 50b1 having a rectangular parallelepiped shape can increase the contact area with the heat sink compared to a flat portion having a cylindrical shape, thereby improving heat dissipation efficiency. The bottom 50b before the recess 50b3 is provided may be formed by, for example, press processing.

[0076] The bottom portion 50b may be made of at least one metal selected from the group consisting of copper, iron, copper alloys, and iron alloys, for example. The bottom portion 50b made of such a metal with high thermal conductivity can efficiently transfer heat generated from the semiconductor laser device 20 to the outside.

[0077] The dimensions of the flat portion 50b1 of the bottom 50b in each of the X and Z directions may be, for example, 5 mm to 10 mm, and the dimension in the Y direction may be, for example, 3 mm to 10 mm. The dimensions of the convex portion 50b2 of the bottom 50b in each of the X and Z directions may be, for example, 3 mm to 9 mm, and the dimension in the Y direction may be, for example, 1 mm to 8 mm. The dimension of the concave portion 50b3 in the X direction may be, for example, 1 mm to 7 mm, the dimension in the Y direction may be, for example, 10 μm to 3 mm, and the dimension in the Z direction may be, for example, 1 mm to 7 mm.

[0078] [Lead terminal 60] The two lead terminals 60 supply power to the laser light source 100A via a plurality of wires 60w shown in FIG. 1C. One of the lead terminals 60 is electrically connected to the upper surface of the semiconductor laser element 20 shown in FIG. 2A via some of the plurality of wires 60w. The other lead terminal 60 is electrically connected to the first metal film 10m1 shown in FIG. 2A via the remaining portions of the plurality of wires 60w. The first metal film 10m1 is electrically connected to the lower surface of the semiconductor laser element 20. Electrodes are provided on each of the upper and lower surfaces of the semiconductor laser element 20.

[0079] Each lead terminal 60 may have, for example, a cylindrical shape. Each lead terminal 60 may be formed, for example, from an Fe—Ni alloy having a copper core. The copper core is arranged along the central axis of the cylinder of the lead terminal 60. In other words, a cylindrical Fe—Ni alloy is formed around a cylindrical copper. Since the lead terminal 60 has copper, a material with low electrical resistance, in its center, it becomes possible for a large current to flow through each lead terminal 60.

[0080] The diameter of each lead terminal 60 in the XY plane may be, for example, 0.6 mm or more and 2.0 mm or less, and the dimension in the Z direction may be, for example, 5 mm or more and 20 mm or less. The dimension of the gap between two lead terminals 60 may be, for example, 1 mm or more and 8 mm or less.

[0081] [Lead holding member 70] 1D, the lead holding member 70 is bonded to the side wall 50w with an inorganic bonding material so that the through-holes 70h in the lead holding member 70 overlap the through-holes 50h in the side wall 50w. The inorganic bonding material may be, for example, a brazing material such as silver solder. The lead holding member 70 may be made of, for example, mild steel, which is iron with a carbon content of 0.05% to 0.3%, or kovar.

[0082] The bonding member 72 may be made of, for example, soft glass. Mild steel and Kovar are conductive materials, while soft glass is an electrically insulating material. The bonding member 72 can prevent short-circuiting between the two lead terminals 60 and improve the sealing performance of the package.

[0083] The thermal expansion coefficient of the lead holding member 70 can be designed to be, for example, equal to or greater than that of the side wall 50w and equal to or less than that of the lead terminals 60. In this case, the lead holding member 70 relieves the thermal stress between the side wall 50w and the lead terminals 60, thereby improving the package's durability against thermal stress.

[0084] The dimension of the lead holding member 70 in the X direction may be, for example, 5 mm to 10 mm, the dimension in the Y direction may be, for example, 2 mm to 8 mm, and the dimension in the Z direction may be, for example, 0.5 mm to 5 mm.

[0085] [Cover 80] 3A, the cover 80 is joined to the upper surface of the side wall 50w via a reinforcing member 52. The cover 80, together with the base 50 and the lead holding member 70, seals the space in which the laser light source 100A is housed. However, the cover 80 may be omitted if it is not necessary to seal the laser light source 100A. The dimensions of the cover 80 in each of the X and Z directions may be, for example, 5 mm or more and 10 mm or less, and the dimension in the Y direction may be, for example, 0.05 mm or more and 1 mm or less.

[0086] The reinforcing member 52 improves the sealing performance of the cover 80. In a configuration without the reinforcing member 52, a gap may occur between the upper surface of the side wall 50w and the cover 80. The cover 80 and the reinforcing member 52 may be made of, for example, Kovar. In a configuration in which the cover 80 and the reinforcing member 52 are made of the same material as the side wall 50w, their thermal expansion coefficients are the same, improving the package's resistance to thermal stress.

[0087] Details of the side wall 50w, the two lead terminals 60, and the lead holding member 70 of the package of the light emitting device 100 according to this embodiment are disclosed in, for example, Japanese Patent Application Laid-Open No. 2021-106247. The entire disclosure of Japanese Patent Application Laid-Open No. 2021-106247 is incorporated herein by reference. [Industrial Applicability]

[0088] The light emitting device according to the present disclosure can be used in, for example, a laser processing machine, a projector, and an illumination light source. [Explanation of symbols]

[0089] 10 Submount 10m1 1st metal film 10m2 2nd metal membrane 10s1 Top surface of submount 10s2 Bottom surface of submount 20 Semiconductor laser element 20L laser light 20e exit surface 30 Lens support member 30L connection part 30p columnar part 30s1 End face of columnar part 30s2 End face of connecting part 40 lenses 50, 50a base 50b, 50ba bottom 50b1 Flat plate part 50b2 Convex part 50b3 Recess 50b4 Specified area 50bp Periphery of the plate 50bs1 Top of bottom 50bs2 bottom surface 50c cap 50g Joint material 50h Sidewall through-hole 50t transparent part 50w sidewall 52 Reinforcement member 60 Lead terminal 60w wire 70 Lead holding member 70h Lead holding member through hole 72 Joint materials 80 Cover 90 Press equipment 92 Stages 92s top 94 Pressing part 94s Lower end of pressing part 96 Support member for pressing part 100 Light-emitting device 100A laser light source

Claims

1. a semiconductor laser element; a base having a bottom supporting the semiconductor laser element and a sidewall surrounding the semiconductor laser element, the sidewall having a light-transmitting portion that transmits laser light emitted from the semiconductor laser element, and the sidewall being joined to the bottom; a cover that, together with the base, forms a sealed space that seals the semiconductor laser element; two lead terminals disposed through the side wall, each with one end disposed inside the sealed space; Equipped with the bottom portion has an upper surface, and the upper surface is provided with a recess located between the two lead terminals in a top view; The recess has a flat bottom surface on which the semiconductor laser element is disposed.

2. the base has a planar lower surface; The light emitting device according to claim 1 , wherein the bottom surface of the recess is parallel to the lower surface of the base.

3. a submount having an upper surface and a lower surface, the upper surface of the submount supporting the semiconductor laser device; a metal film provided on the lower surface of the submount; Furthermore, the metal film and the bottom surface of the recess are bonded together with a bonding material, the thickness of the metal film is greater than the depth of the recess; a width of the metal film in a direction in which the two lead terminals are spaced apart from each other in a top view is equal to or smaller than a width of the recess; 3. The light emitting device according to claim 1, wherein the width of the submount in the separation direction is greater than the width of the recess and smaller than the dimension of the gap between the two lead terminals.

4. the height of the side wall is 0.2 times or more and 0.5 times or less the circumferential length of the outer periphery of the side wall, the bottom portion has a flat portion and a convex portion that forms a step with the flat portion, the recess is provided on an upper surface of the protrusion, The light emitting device according to claim 1 , wherein a dimension of the step in the normal direction of the upper surface of the convex portion is 0.25 to 0.5 times the height of the side wall.

5. the wavelength of the laser light is 420 nm or more and 450 nm or less, The light emitting device according to claim 1 , wherein the output of the laser light is 10 W or more.

6. The light emitting device according to claim 1 , further comprising a lens disposed inside the sealed space for collimating or focusing the laser light emitted from the semiconductor laser element.

7. a lens support member supported by 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; The light emitting device of claim 3 further comprising:

8. preparing a package body including a base having a bottom and side walls that form a space for accommodating a semiconductor laser element, and two lead terminals that are disposed through the side walls and have one end each disposed within the space; a step of pressing a predetermined region of the upper surface of the bottom portion from between the two lead terminals using a press device to form a recess having a flat bottom surface on the upper surface of the bottom portion; A method for manufacturing a package, comprising:

9. The method of manufacturing a package according to claim 8 , wherein the step of providing the package body includes the step of bonding the sidewall to the bottom.

10. 10. The method for manufacturing a package according to claim 8, wherein the step of forming the recess in the upper surface of the bottom portion includes making the bottom surface of the recess and the lower surface of the base flat and parallel to each other.

11. a step of manufacturing a package by the method of manufacturing a package according to any one of claims 8 to 10; placing the semiconductor laser element on the bottom surface of the recess; A method for manufacturing a light emitting device, comprising:

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