Submount, light emitting device, and optical module

Abstract

The sub-base on which the light-emitting device is mounted comprises: a base having a first surface extending in a first direction and a second direction orthogonal to the first direction; a first electrode extending in the first direction and the second direction on the first surface, having a first end in the second direction and a second end in the opposite direction to the second direction extending in the first direction; and a second electrode extending in the first direction and the second direction on the first surface, having a third end in the opposite direction to the second direction separated from the first end by a gap in the second direction and a fourth end in the second direction extending in the first direction, wherein the second width in the second direction between the third end and the fourth end of the second electrode varies according to the position in the first direction.

Description

Technical Field

[0001] This invention relates to a submount, a light-emitting device, and an optical module. Background Technology

[0002] A semiconductor laser module is known to include a semiconductor laser chip as a light-emitting device and an optical fiber optically coupled to the semiconductor laser chip as an optical module. When manufacturing such a semiconductor laser module, assembly is performed, for example, by the following process: First, the semiconductor laser chip is mounted on a sub-base. At this time, the semiconductor laser chip is bonded to the sub-base using a solder such as a gold-tin (AuSn) alloy (Patent Document 1). Alternatively, other bonding agents such as conductive adhesives can be used instead of solder. The sub-base on which this semiconductor laser chip is mounted (semiconductor laser chip mounting sub-base) is an example of a light-emitting device, also referred to as a chip-on-submount.

[0003] Next, the chip on the sub-base is directly or indirectly mounted to a metal frame using solder such as a tin-bismuth (SnBi) alloy via a metal base and electronic cooling components. Then, other optical components such as lenses are mounted on the frame to achieve optical coupling between the semiconductor laser chip and the optical fiber.

[0004] As semiconductor laser chips, end-emitting semiconductor laser chips are more commonly used. In an end-emitting semiconductor laser chip, one of the two end faces along the long side becomes the rear end face, which has a high reflection (HR) coating with high reflectivity at the laser oscillation wavelength. On the other hand, the other end face becomes the exit end face, which has an low reflection (AR) coating. The rear end face and the exit end face constitute the laser resonator, and the oscillating laser light is mainly emitted from the exit end face.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 5075165 Summary of the Invention

[0008] -The problem the invention aims to solve-

[0009] Generally, semiconductor laser chips are mounted to a sub-substrate via die bonding. In die bonding, a clamp is used to vacuum-adhere the semiconductor laser chip, mounting it onto a sub-substrate heated to a temperature above the melting point of the solder or other bonding agent.

[0010] Subsequently, in order to supply driving current to the semiconductor laser chip and ensure electrical contact with the semiconductor laser chip, bonding wire-based wiring is formed between the semiconductor laser chip and the electrodes on the sub-substrate. Additionally, when the semiconductor laser chip mounting sub-substrates are arranged side-by-side, bonding wire-based wiring is sometimes formed between the sub-substrates.

[0011] On the other hand, in recent years, the miniaturization of semiconductor laser chips and sub-substrates has made it difficult to ensure the bonding of wire-based wiring on the electrodes of semiconductor laser chips and sub-substrates.

[0012] Furthermore, semiconductor laser chips are increasingly moving towards higher light output. Consequently, effectively dissipating the heat generated by the semiconductor laser chip to the sub-substrate is becoming increasingly important.

[0013] Therefore, one of the objectives of this invention is to obtain, for example, a sub-base, a light-emitting device, and an optical module that allow for easier bonding of wiring to electrodes and readily achieve the desired heat dissipation.

[0014] -Methods for solving problems-

[0015] The sub-base of the present invention is a sub-base on which a light-emitting device is mounted, comprising: a base having a first surface extending in a first direction and a second direction orthogonal to the first direction; a first electrode extending on the first surface in both the first and second directions, having a first end in the second direction and a second end in the opposite direction to the second direction extending in the first direction; and a second electrode extending on the first surface in both the first and second directions, having a third end in the opposite direction to the second direction separated from the first end by a gap in the second direction and a fourth end in the second direction extending in the first direction, wherein the second width of the second electrode in the second direction between the third end and the fourth end varies depending on the position in the first direction.

[0016] In the sub-base, the first width in the second direction between the first end and the second end of the first electrode varies depending on the position of the first direction.

[0017] The light-emitting device of the present invention comprises: the sub-base; and a light-emitting element having a back side disposed on and electrically connected to the first electrode and a surface electrically connected to a conductor via a second electrode on the side opposite to the back side, extending closer to the first end than the second end and extending in the first direction.

[0018] In the light-emitting device, the light-emitting element is a semiconductor laser element with gallium arsenide or indium phosphide.

[0019] The optical module of the present invention comprises a housing having a substrate and at least one light-emitting device disposed on the substrate as the light-emitting device.

[0020] The optical module, as the light-emitting device, has a plurality of light-emitting devices arranged in the second direction.

[0021] -Invention Effects-

[0022] According to the present invention, it is possible to obtain a sub-base, a light-emitting device, and an optical module that allow for easier bonding of wiring on the electrodes and facilitates obtaining the desired heat dissipation. Attached Figure Description

[0023] Figure 1 This is an illustrative and schematic top view of the optical module of the first embodiment.

[0024] Figure 2 This is an illustrative and schematic side view (partial cross-sectional view) of the optical module of the first embodiment.

[0025] Figure 3 This is an illustrative and schematic top view of the optical device according to the first embodiment.

[0026] Figure 4 for Figure 3 Sectional view IV-IV.

[0027] Figure 5 for Figure 3 VV sectional view.

[0028] Figure 6 This is an illustrative and schematic top view of the optical module of the second embodiment.

[0029] Figure 7 This is an illustrative and schematic top view of the optical module of the third embodiment.

[0030] Figure 8 This is an illustrative and schematic top view of the optical module of the fourth embodiment. Detailed Implementation

[0031] The following are exemplary embodiments of the present invention. The structure of the embodiments shown below, as well as the effects and results (compliance) resulting from such structures, are examples. The present invention can also be implemented using structures other than those disclosed in the following embodiments. Furthermore, according to the present invention, at least one of various effects (including derived effects) obtained through the structure can be obtained.

[0032] The embodiments shown below have the same structure. Therefore, based on the structure of each embodiment, the same function and effect are obtained based on the same structure. In addition, the same symbols are sometimes given to these same structures below, and repeated descriptions are omitted.

[0033] Furthermore, in each figure, arrow X represents the X direction, arrow Y represents the Y direction, and arrow Z represents the Z direction. The X, Y, and Z directions intersect and are orthogonal. The X direction is the emission direction of the laser from the light-emitting element and optical device, and is the direction of the long side of the light-emitting element (the long side of the resonator). The Y direction is the width direction of the light-emitting element. Additionally, the Z direction is the thickness direction (height direction) of the sub-base.

[0034] [First Implementation]

[0035] [Structure of a semiconductor laser module]

[0036] Figure 1 This is a top view of the semiconductor laser module 100. Figure 2 This is a side view (partial cross-sectional view) of the semiconductor laser module 100. The semiconductor laser module 100 is an example of an optical module.

[0037] The semiconductor laser module 100 has a cover 1a (see reference) Figure 2 The outer shell 1 of the casing 1b and the outer shell 1. The outer shell 1 is made of, for example, a metallic material. Additionally, in Figure 1 For ease of explanation, the illustration of cover 1a is omitted. In other words, Figure 1 This is a top view showing the internal structure of the semiconductor laser module 100 after the cover 1a has been removed.

[0038] Furthermore, the semiconductor laser module 100 includes a stepped module substrate 2, multiple sub-bases 3, and multiple semiconductor laser chips 4. The module substrate 2 is made of a metal material with high thermal conductivity, such as copper. The semiconductor laser chip 4 is an example of a light-emitting element. Additionally, a sub-assembly including the sub-bases 3 and the semiconductor laser chips 4, mounted on the module substrate 2, is a chip-on-subbase 16. The chip-on-subbase 16 is an example of a light-emitting device.

[0039] In addition, the semiconductor laser module 100 has two lead pins 5. The two lead pins 5 are connected via a sub-base 3, a bonding wire 18, and a bonding wire 17 (see reference). Figure 3The bonding wires 17 and 18 are electrically connected to each semiconductor laser chip 4 and supply power to each semiconductor laser chip 4. Furthermore, the semiconductor laser module 100 includes six first lenses 6, six second lenses 7, six reflectors 8, a third lens 9, an optical filter 10, and a fourth lens 11. Each first lens 6, each second lens 7, each reflector 8, the third lens 9, the optical filter 10, and the fourth lens 11 are arranged sequentially along the optical path of the laser emitted from each semiconductor laser chip 4. Furthermore, the semiconductor laser module 100 includes an optical fiber 12 disposed opposite to the fourth lens 11. One end of the laser incident on the optical fiber 12 is housed inside the housing 1 and supported by a support member 13. The bonding wires 17 and 18 can also be referred to as wiring or conductors.

[0040] Each semiconductor laser chip 4 is constructed primarily of gallium arsenide (GaAs) or indium phosphide (InP), and outputs laser light with a wavelength corresponding to the material and composition of that chip. The thickness of each semiconductor laser chip 4 is, for example, approximately 0.1 mm. Figure 2 As shown, each semiconductor laser chip 4 is mounted on a sub-base 3, and each sub-base 3 is mounted on the module substrate 2 at a different height. Furthermore, each first lens 6, each second lens 7, and each reflector 8 are respectively configured at a height corresponding to the corresponding semiconductor laser chip 4. The module includes a sub-base 3, a semiconductor laser chip 4 mounted on the sub-base 3, and bonding wires 17 (see reference 1). Figure 3 The sub-component is chip 16 on the sub-base, which serves as a mounting sub-base for semiconductor laser chips.

[0041] Furthermore, a tapered tube 15 is provided at the insertion part where the optical fiber 12 is inserted into the housing 1, and a protective cover 14 is embedded in a part of the housing 1 to cover a part of the tapered tube 15 and the insertion part.

[0042] The operation of the semiconductor laser module 100 will now be explained. Each semiconductor laser chip 4 is operated by power supplied via lead pins 5 and outputs laser light. Each laser beam output from each semiconductor laser chip 4 is approximately collimated by its corresponding first lens 6 and second lens 7, and reflected by its corresponding reflector 8 toward the third lens 9. Furthermore, each laser beam is focused by the third lens 9 and fourth lens 11 and reflected onto the end face of the optical fiber 12, where it propagates. In addition, the optical filter 10 is a bandpass filter, which prevents light with a wavelength different from the laser wavelength from being input into the semiconductor laser module 100 via the optical fiber 12 from entering the semiconductor laser module 100.

[0043] The assembly of the semiconductor laser module 100 is performed, for example, by the following process: First, the sub-base 3 is heated to approximately 300°C, which is the bonding temperature, and the semiconductor laser chip 4 is bonded to the sub-base 3 using AuSn solder with a melting point of approximately 280°C, forming six chips 16 on the sub-base. Next, the housing 1b of the outer casing 1, on which the module substrate 2 is mounted, is heated to approximately 150°C, which is the bonding temperature, and the chips 16 on each sub-base are bonded to the module substrate 2 using SnBi solder with a melting point of approximately 140°C. Afterward, other structural components of the semiconductor laser module 100 are assembled to the outer casing 1.

[0044] [Structure of the chip on the sub-base]

[0045] Figure 3 This is a top view of chip 16 on the sub-base. Figure 4 for Figure 3 Sectional view IV-IV, in addition, Figure 5 for Figure 3 The VV cross-sectional view. As described above, the chip 16 on the sub-base includes a semiconductor laser chip 4, a sub-base 3 on which the semiconductor laser chip 4 is mounted, and a bonding wire 17.

[0046] like Figure 3 , 4 As shown, the sub-base 3 includes a substrate 3a and an upper coating layer 3b. The substrate 3a may include at least one of, for example, aluminum nitride (AlN), aluminum oxide (Al2O3), beryllium oxide (BeO), boron nitride (BN), diamond, silicon carbide (SiC), silicon nitride (Si3N4), silicon dioxide (SiO2), and zirconium oxide (ZrO2). In this embodiment, the semiconductor laser chip 4 is a single-emission type, but it may also be a multi-emission type laser rod chip. When the semiconductor laser chip 4 is a laser rod chip, the substrate 3a may also be a metal such as Cu. In this embodiment, the substrate 3a is a substrate made of AlN. Furthermore, the thickness of the substrate 3a is, for example, about 0.3 to 1.0 mm. The substrate 3a is an example of a substrate.

[0047] from Figure 3 , 4 It can be seen that the substrate 3a has a flat cuboid shape that is relatively thin in the Z direction; in other words, it has a quadrilateral shape and a plate-like shape.

[0048] like Figure 4As shown, substrate 3a has a surface 3a1, a back surface 3a2, and side surfaces 3a3 and 3a4. Surface 3a1 intersects and is orthogonal to the Z-direction at its end in the Z-direction, and extends in both the X and Y directions. Back surface 3a2 intersects and is orthogonal to the Z-direction at its end in the opposite direction of the Z-direction, and extends in both the X and Y directions. Surface 3a1 and back surface 3a2 are parallel. Furthermore, side surface 3a3 intersects and is orthogonal to the Y-direction at its end in the opposite direction of the Y-direction, and extends in both the X and Z directions. Side surface 3a4 intersects and is orthogonal to the Y-direction at its end in the Y-direction, and extends in both the X and Z directions. Surface 3a1 is an example of a first surface.

[0049] Figure 3 , 4 The upper coating layer 3b shown is formed on the surface 3a1 of the substrate 3a, that is, on the side of the semiconductor laser chip 4 that is mounted. The upper coating layer 3b is, for example, a metal multilayer film. The thickness of the upper coating layer 3b is, for example, more than 1 μm and less than 80 μm.

[0050] The upper coating layer 3b is separated into a first electrode 3b1 and a second electrode 3b2 by a gap g. The gap g electrically insulates the first electrode 3b1 and the second electrode 3b2. Figure 3 In such a top view, that is, when viewed from the opposite direction of the Z direction, the surface 3a1 of the substrate 3a is exposed between the first electrode 3b1 and the second electrode 3b2 by setting a gap g.

[0051] The first electrode 3b1 is connected via bonding line 18 (see reference). Figure 1 ,exist Figure 3 (Not shown in the diagram) The second electrode 3b2 of the chip 16 on other sub-bases, such as the second electrode 3b2 of the chip 16 on the sub-base adjacent in the opposite direction of the Y direction, is electrically connected. Furthermore, the second electrode 3b2 is also electrically connected via bonding wire 18 to the first electrode 3b1 of the chip 16 on other sub-bases, such as the first electrode 3b1 of the chip 16 on the sub-base adjacent in the Y direction. Additionally, the second electrode 3b2 is electrically connected to the surface 4b of the semiconductor laser chip 4 via bonding wire 17.

[0052] For ease of explanation, Figure 3 Only a portion of the bond line 17 is shown in the diagram, and... Figure 4 The diagram of bonding wire 17 is omitted. Multiple bonding wires 17 are arranged at certain intervals in the X direction, electrically connecting the second electrode 3b2 in parallel to the surface 4b of the semiconductor laser chip 4. (See diagram for reference.) Figure 3 As shown, the plurality of bond lines 17 include longer bond lines 17 and shorter bond lines 17, which are arranged alternately in the X direction. Figure 3 In the diagram, multiple bond lines 17 are omitted in the middle part of the X direction.

[0053] The semiconductor laser chip 4 is bonded to the first electrode 3b1 via a pre-coating 3c. The pre-coating 3c is, for example, AuSn solder, which electrically connects the first electrode 3b1 to the back surface 4a of the semiconductor laser chip 4. Additionally, a barrier metal layer (not shown), for example made of platinum (Pt), can be formed on the surface of the upper coating layer 3b that contacts the pre-coating 3c. In this case, the barrier metal layer prevents chemical reaction between the AuSn solder of the pre-coating 3c and the metal material located below the barrier metal layer of the upper coating layer 3b.

[0054] Electrodes are formed on the back surface 4a and surface 4b of the semiconductor laser chip 4, respectively, and the semiconductor laser chip 4 is powered from the lead pin 5 via these electrodes. Furthermore, when the semiconductor laser chip 4 is mounted with the junction facing downwards, an n-side electrode is generally formed on the surface 4b side. Conversely, when the semiconductor laser chip 4 is mounted with the junction facing upwards, a p-side electrode is generally formed on the surface 4b side. Additionally, the side of the semiconductor laser chip 4 mounted with the junction facing downwards has better heat dissipation towards the sub-base 3.

[0055] [The shapes of the first electrode, the second electrode, and the gap]

[0056] like Figure 3 As shown, in this embodiment, the widths d11, d12, and d13 of the first electrode 3b1 in the Y direction vary depending on its position in the X direction. Similarly, the widths d21, d22, and d23 of the second electrode 3b2 in the Y direction also vary depending on its position in the X direction. Furthermore, the gap g is bent. Additionally, the width dg of the gap g in the Y direction is fixed regardless of its position in the X direction, but this is not a limitation. Widths d11, d12, and d13 are examples of a first width, and widths d21, d22, and d23 are examples of a second width.

[0057] The width of the first electrode 3b1 is the width between its first end 3d1 and second end 3d2. The first end 3d1 is the end of the first electrode 3b1 in the Y direction, facing the gap g. Furthermore, the second end 3d2 is the end of the first electrode 3b1 in the opposite direction to the Y direction, extending along the X direction. Additionally, as... Figure 4 , 5 As shown, the second end 3d2 overlaps with the side 3a3 in the Z direction, but it is not limited to this and can also be located at a position offset from the side 3a3 in the Y direction.

[0058] The width of the second electrode 3b2 is the width between its third end 3d3 and fourth end 3d4. The third end 3d3 is the end of the second electrode 3b2 in the opposite direction to the Y direction, facing the gap g, and sandwiching the gap g while facing and separating from the first end 3d1 of the first electrode 3b1. Furthermore, the fourth end 3d4 is the end of the second electrode 3b2 in the Y direction and extends along the X direction. Additionally, as... Figure 4 , 5 As shown, the fourth end 3d4 overlaps with the side 3a4 in the Z direction, but it is not limited to this and can also be located at a position offset from the side 3a4 in the opposite direction to the Y direction.

[0059] In this embodiment, the width d13 is larger (wider) than the width d11, and the width d23 is smaller (narrower) than the width d21. Furthermore, the width d12 gradually increases (wider) from the width d11 to the width d13 as it faces the X direction, while the width d22 gradually decreases (narrower) from the width d21 to the width d23 as it faces the X direction.

[0060] The bonding wire 18, electrically connected to the second electrode 3b2, is mounted in a mounting area A with a width d21 that is larger than the widths d22 and d23. For example... Figure 3 As shown, the bonding wire 18 is electrically connected to the second electrode 3b2 via solder 19. Now, assuming that the gap g extends straight along the X direction and the width of the second electrode 3b2 is fixed at a relatively narrow width d23, the mounted area A, which is the area where the solder 19 can extend, becomes narrower. Due to interference between the bonding wire 18, solder 19, and bonding wire 17, it may be difficult to mount them onto the second electrode 3b2. In this embodiment, the widths d21, d22, and d23 vary depending on their position in the X direction. The area of ​​the mounted area A, which extends in the X direction with a width d21 that is larger than the widths d22 and d23, can be set to be larger, thus preventing interference between the bonding wire 18 and bonding wire 17 and facilitating bonding on the second electrode 3b2. Furthermore, if, as in this embodiment, the width dg of the gap g is fixed along the X direction, or if the width dg does not change much along the X direction, then as the widths d21, d22, and d23 of the second electrode 3b2 change in the X direction, the widths d11, d12, and d13 of the first electrode 3b1 also change in the X direction. Here, since the widths of the substrate 3a, the upper coating layer 3b, and the sub-base 3 in the Y direction are approximately fixed along the X direction, the larger the width of the first electrode 3b1, the smaller the width of the second electrode 3b2 becomes, and vice versa.

[0061] However, since the width d21 of the second electrode 3b2 is larger than the widths d22 and d23, it is easier to install the bonding wire 18 at locations such as... Figure 4As shown, the distance between the semiconductor laser chip 4 and the first end 3d1 in the Y direction is relatively short. Therefore, the heat H transferred from the semiconductor laser chip 4 via the pre-coating 3c and the first electrode 3b1 in the opposite direction to the Y direction (in the Z direction) is relatively small. Figure 4 The thin dashed line pointing to the lower right of the image shows the heat H transferred from the semiconductor laser chip 4 via the pre-coating 3c and the first electrode 3b1 in the opposite direction to the Y direction and the opposite direction to the Z direction. Figure 4 The thick dashed line pointing to the lower left is small. However, in this embodiment, as described above, the width of the second electrode 3b2 in the Y direction varies along the X direction. Figure 5 The position of the cross section, and Figure 4 The cross-sectional position is relatively long compared to the distance in the Y direction between the semiconductor laser chip 4 and the first end 3d1. Therefore, at this position, the heat H transferred from the semiconductor laser chip 4 via the pre-coating 3c and the first electrode 3b1 in the opposite direction to the Y direction (in the Z direction) is greater. Figure 5 The thick dashed line pointing to the lower right is larger than... Figure 4 The cross-sectional area is large. Furthermore, this heat H can be transferred from the semiconductor laser chip 4 via the pre-coating 3c and the first electrode 3b1 in the opposite direction to the Y direction and the opposite direction to the Z direction. Figure 5 The thick dashed line pointing to the lower left is roughly the same.

[0062] Additionally, the bonding line 18 of the first electrode 3b1 (see reference) Figure 1 ,exist Figure 3 The mounting area A (not shown in the figure) and the mounting area A of the second electrode 3b2 are arranged in the Y direction, but are not limited thereto.

[0063] As explained above, in this embodiment, the width of the second electrode 3b2 in the Y direction varies depending on its position in the X direction.

[0064] According to this structure, a relatively wide mounting area A can be set in the second electrode 3b2 at a width d21 that is larger than the widths d22 and d23. Furthermore, in the second electrode 3b2, a relatively long distance in the Y direction between the semiconductor laser chip 4 and the first end 3d1 can be achieved at a width d22 and d23 that is smaller than the width d21, i.e., a width larger than the widths d11 and d12 in the first electrode 3b1. Therefore, according to this structure, a sub-base 3, a chip-on-the-subbase having the sub-base 3, and a semiconductor laser module 100 having the chip-on-the-subbase 16 can be obtained, which allows for easier bonding of the bonding wire 18 to the second electrode 3b2 of the sub-base 3 and facilitates desirable heat dissipation.

[0065] Furthermore, in this embodiment, the width of the first electrode 3b1 in the Y direction varies depending on its position in the X direction.

[0066] Based on this structure, in the first electrode 3b1, the portion with a width larger than the widths d11 and d12 can easily ensure heat dissipation from the semiconductor laser chip 4.

[0067] [Second Implementation]

[0068] Figure 6 This is a top view of the chip 16A on the sub-base in this embodiment. Figure 6 As shown, in this embodiment, the gap g extends straight with an inclination relative to the X direction. Therefore, the width d1 of the first electrode 3b1 gradually increases (widens) towards the X direction, while the width d2 of the second electrode 3b2 gradually decreases (narrows) towards the X direction.

[0069] In this embodiment, a wider mounting area A can be provided in a region where the width d2 is larger than other regions in the second electrode 3b2. Furthermore, in a region where the width d1 is larger than other regions in the first electrode 3b1, the distance in the Y direction between the semiconductor laser chip 4 and the first end 3d1 can be longer. Therefore, according to this embodiment, it is possible to more easily bond the bonding wire 18 to the second electrode 3b2 of the sub-base 3A, and to easily obtain the desired heat dissipation, the sub-base 3A, the chip 16A on the sub-base 3A, and the semiconductor laser module 100 having the chip 16A on the sub-base 3A.

[0070] [Third Implementation]

[0071] Figure 7 This is a top view of the chip 16B on the sub-base in this embodiment. In the first embodiment, as... Figure 3 As shown, the width d13 of the end of the first electrode 3b1 in the X direction (the laser emission direction) is larger (wider) than the widths d11 and d12, and the width d23 of the end of the second electrode 3b2 in the X direction is smaller (narrower) than the widths d21 and d22. In contrast, in this embodiment, as... Figure 7 As shown, the width d13 of the end of the first electrode 3b1 in the X direction is smaller (narrower) than the widths d11 and d12, and the width d23 of the end of the second electrode 3b2 in the X direction is larger (wider) than the widths d21 and d22.

[0072] In this embodiment, a relatively wide mounting area A can be set in the second electrode 3b2 at a portion with a width d23 that is larger than the widths d21 and d22. Furthermore, at positions where the width of the first electrode 3b1 is a width d11 or d12 that is larger than the width d13, the distance in the Y direction between the semiconductor laser chip 4 and the first end 3d1 can be relatively long. Therefore, according to this embodiment, it is possible to obtain a sub-base 3B, a chip-on-subbase 16B having the sub-base 3B, and a semiconductor laser module 100 having the chip-on-subbase 16B, all of which allow for easier bonding of the bonding wire 18 to the second electrode 3b2 of the sub-base 3B and provide desirable heat dissipation.

[0073] [Fourth Implementation]

[0074] Figure 8 This is a top view of the chip 16C on the sub-base according to this embodiment. In this embodiment, the width d12 of the middle portion of the first electrode 3b1 in the X direction is smaller (narrower) than the widths d11 and d13, and the width d22 of the middle portion of the second electrode 3b2 in the X direction is larger (wider) than the widths d21 and d23. Furthermore, the width d11 increases with the direction opposite to the X direction, and the width d21 decreases with the direction opposite to the X direction. The widths d12 and d22 are fixed regardless of their position in the X direction. Additionally, the width d13 increases with the direction of the X direction, and the width d23 decreases with the direction of the X direction.

[0075] In this embodiment, a relatively wide mounting area A can be provided in the second electrode 3b2 at a portion with a width d22 that is larger than the widths d21 and d23. Furthermore, at positions where the width d11 of the first electrode 3b1 is larger than the width d12, and at positions where the width d13 of the first electrode 3b1 is larger than the width d12, the distance in the Y direction between the semiconductor laser chip 4 and the first end 3d1 can be relatively long. Therefore, according to this embodiment, it is possible to obtain a sub-base 3C, a chip-on-a-subbase having the sub-base 3C, and a semiconductor laser module 100 having the chip-on-a-subbase 16C, which allows for easier bonding of the bonding wire 18 to the second electrode 3b2 of the sub-base 3C, and readily obtains the desired heat dissipation properties.

[0076] The above embodiments of the present invention have been illustrated, but these embodiments are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other ways, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the specifications of various structures, shapes, etc. (construction, type, orientation, form, size, length, width, thickness, height, quantity, configuration, position, material, etc.) can be appropriately modified for implementation.

[0077] For example, the sub-base and optical elements of the present invention can be applied to optical devices and optical modules that differ from those disclosed in the above embodiments.

[0078] Furthermore, the shapes of the gap, the first electrode, and the second electrode can be varied.

[0079] Industrial availability

[0080] This invention can be used in sub-bases, light-emitting devices, and optical modules.

[0081] -Symbol Explanation-

[0082] 1a...cover

[0083] 1b...shell

[0084] 1...outer shell

[0085] 2...Module Base

[0086] 3, 3A, 3B, 3C... Sub-base

[0087] 3a...Substrate (base)

[0088] 3a1... Surface (First Surface)

[0089] 3a2...back

[0090] 3a3, 3a4... Side view

[0091] 3b... Upper Covering Layer

[0092] 3b1...First Electrode

[0093] 3b2...Second electrode

[0094] 3c...pre-coating

[0095] 3d1...First End

[0096] 3d2...Second End

[0097] 3d3... Third end

[0098] 3d4...Fourth end

[0099] 4... Semiconductor laser chip

[0100] 4a...back side

[0101] 4b... Surface

[0102] 5...lead pins

[0103] 6...First lens

[0104] 7...Second lens

[0105] 8...reflector

[0106] 9...Third lens

[0107] 10... Optical Filter

[0108] 11... Fourth Lens

[0109] 12... fiber optic

[0110] 13... Support components

[0111] 14... Protective shield

[0112] 15... tapered tube

[0113] Chips on sub-bases: 16, 16A, 16B, 16C...

[0114] 17...bonding wire

[0115] 18...bonding wire

[0116] 19... Solder

[0117] 100... Semiconductor laser module (optical module)

[0118] A... Installation area

[0119] Widths d1, d11, d12, d13... (first width)

[0120] d2, d21, d22, d23... width (second width)

[0121] dg...width

[0122] g...gap

[0123] H... heat (heat).

Claims

1. A sub-base on which a light-emitting element is mounted. The sub-base includes: The base has a first surface extending in a first direction and in a second direction orthogonal to the first direction; A first electrode extends on the first surface in both the first and second directions, having a first end in the second direction and a second end in the opposite direction to the second direction extending in the first direction; and The second electrode extends on the first surface in both the first and second directions, having a third end in the opposite direction of the second direction, separated by a gap from the first end in the second direction, and a fourth end in the second direction extending in the first direction. The width of the first electrode in the second direction varies depending on its position in the first direction. The width of the second electrode in the second direction also varies depending on its position in the first direction. The wider the first electrode, the smaller the width of the second electrode; conversely, the smaller the width of the first electrode, the wider the second electrode. The light-emitting element has: The back side is placed on the first electrode and electrically connected to the first electrode; and On the surface opposite to the back side, electrically connected to the second electrode via a first conductor. The light-emitting element is located on the first electrode. At a position closer to the first end than to the second end, In the portion where the width of the second electrode decreases, that is, in the portion where the width of the first electrode increases, the distance between the semiconductor laser chip and the second direction of the first end is relatively long.

2. The sub-base according to claim 1, wherein, The first width in the second direction between the first end and the second end of the first electrode varies depending on the position in the first direction.

3. A light-emitting device, comprising: The sub-base as described in claim 1 or 2; and The light-emitting element.

4. The light-emitting device according to claim 3, wherein, The light-emitting element is a semiconductor laser element containing gallium arsenide or indium phosphide.

5. The light-emitting device according to claim 3, wherein, The second width in the second direction between the third end and the fourth end of the second electrode, or the first width in the second direction between the first end and the second end of the first electrode, varies depending on the position in the first direction within the range of the arrangement of the light-emitting elements in the second direction.

6. The light-emitting device according to claim 4, wherein, The second width in the second direction between the third end and the fourth end of the second electrode, or the first width in the second direction between the first end and the second end of the first electrode, varies depending on the position in the first direction within the range of the arrangement of the light-emitting elements in the second direction.

7. An optical module, comprising: A housing with a modular base; and At least one light-emitting device, which is a light-emitting device according to any one of claims 3 to 6, is disposed on the module substrate.

8. The optical module according to claim 7, wherein, The light-emitting device has a plurality of light-emitting devices arranged in the second direction.

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