Radiating device of laser diode, high-power semiconductor laser and assembling method

Abstract

The invention provides a heat dissipation device of a laser diode, a high-power semiconductor laser and an assembling method. The heat dissipation device is characterized in that a heat conduction assembly is provided with a plurality of inner holes, and the inner holes can be welded with the laser diode through first welding flux; and the water cooling assembly is in contact with at least one part of the heat conduction assembly and is used for dissipating the heat of the laser diode absorbed by the heat conduction assembly. The laser diode is welded in the inner hole through the welding flux, the problem that in the prior art, a mechanical fixing method limits the product size is solved, the size of the whole optical-mechanical structure is reduced, and the weight is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a heat dissipation device of a laser diode, a high-power semiconductor laser and an assembling method. Background Art

[0002] The existing high-power semiconductor lasers generate large and concentrated heat, which is mainly dissipated by water cooling. The main heat in high-power semiconductor lasers comes from the unused electrical power in the laser diode (LD). The current mainstream LD heat dissipation process of high-power semiconductor lasers is that the heat of the LD is first transferred to the heat sink through a heat-conducting medium, and then the heat in the heat sink is transferred to the water cooling through another heat-conducting medium, and finally the water cooling takes the heat out of the laser. In the entire heat dissipation process, the heat-conducting medium, the heat sink and the water cooling are the key to the heat dissipation performance of the entire laser.

[0003] In the current mainstream laser cooling system, LD is mostly fixed to the heat sink by mechanical fixing method, and thermal conductive silicone grease is filled between the two to reduce thermal resistance. Thermal conductive silicone grease is also filled between the heat sink and the water cooling. The use of silicone grease materials is volatile and can contaminate optical lenses in a closed space, affecting the life of the laser. Summary of the invention

[0004] The present invention provides a heat dissipation device for a laser diode, which can get rid of the size limitation of mechanical parts in a mechanical fixing method, reduce the size of the entire optical-mechanical structure and reduce the weight.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A heat dissipation device for a laser diode, comprising:

[0007] A heat-conducting component is provided with a plurality of inner holes, wherein the inner holes can be welded to the laser diode through a first solder; and a water-cooling component is in contact with at least a portion of the heat-conducting component, wherein the water-cooling component is used to dissipate the heat of the laser diode absorbed by the heat-conducting component.

[0008] In order to further improve the welding effect and form multi-sided welding, the inner hole is designed to have a first step that matches the tube seat of the laser diode and a second step that matches the tube cap of the laser diode, and the first solder is filled between the inner side surface of the first step and the step surface and the laser diode.

[0009] Preferably, the heat-conducting component is a plurality of heat sinks placed side by side, and the inner hole is opened at one end of the heat sink close to the water cooling component.

[0010] The present invention also provides a high-power semiconductor laser, comprising a plurality of laser diodes and the above-mentioned heat dissipation device, wherein the heat dissipation device is used for performing heat dissipation processing on the plurality of laser diodes.

[0011] The present invention also provides a method for assembling a high-power semiconductor laser, comprising the following steps:

[0012] Installing a first annular solder preform into the inner hole of the heat conducting component so that the first solder preform is in contact with the inner side surface of the first step;

[0013] The heat-conducting component placed with the inner hole facing upward is heated to the melting point of the first preform solder, so that the first preform solder sequentially wets the inner side surface and the step surface of the first step to form a first solder;

[0014] Installing the laser diode into the inner hole so that the first solder is filled between the tube base of the laser diode and the first step, and between the tube cap of the laser diode and the second step;

[0015] The thermal conductive component is soldered to the water cooling component using a second preform solder.

[0016] It can be seen from the above technical solutions that the present invention welds the laser diode in the inner hole by solder, thereby solving the limitation of the mechanical fixing method in the prior art on the product size, reducing the size of the entire optomechanical structure and reducing the weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the heat dissipation device of the present invention;

[0018] Figure 2 It is a schematic diagram of the structure and assembly of the heat-conducting component, and shows the assembly diagram of the laser diode and the first preformed solder, as well as a partial enlarged diagram of the inner hole.

[0019] Figure 3 It is a schematic diagram of the assembly of the heat conduction component and the water cooling component;

[0020] Figure 4 The figure is a schematic diagram of the assembly of the water cooling component. DETAILED DESCRIPTION

[0021] A preferred embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0022] The heat dissipation device of the present invention is a device for quickly dissipating heat for a laser diode 30, wherein the laser diode 30 includes a tube seat 31 and a tube cap 32 forming a step structure, the tube seat 31 is the main heat dissipation surface of the laser diode, and the heat dissipation device needs to be in contact with the tube seat 31 of the laser diode as much as possible to form effective heat conduction.

[0023] like Figure 1As shown, the heat dissipation device of the present invention includes a heat-conducting component 10 directly in contact with the laser diode 30, and a water-cooling component 20 for dissipating the heat of the laser diode absorbed by the heat-conducting component 10.

[0024] The heat-conducting component 10 is provided with a plurality of inner holes 11 for welding the laser diode 30. For better assembly, in the present embodiment, the heat-conducting component 10 uses a plurality of heat sinks 13 placed side by side. The inner holes 11 are provided at one end of the heat sink 13 close to the water-cooling component 20. The number of inner holes 11 provided on each heat sink 13 and the number of heat sinks 13 are increased or decreased according to the requirements of the laser.

[0025] The present invention welds the laser diode 30 in the inner hole 11 by means of a first solder, thereby avoiding the disadvantages caused by mechanical fixation. In this embodiment, the inner hole 11 adopts a stepped hole structure matched with the laser diode 30, specifically including a first step 111 matched with the tube seat 31 of the laser diode and a second step 112 matched with the tube cap 32 of the laser diode. When assembling, the laser diode 30 is inserted into the inner hole 11, and the stepped hole structure can be well fitted with the tube seat 31 of the laser diode, and the first solder is filled between the inner side surface A and the step surface B of the first step 111 and the laser diode 30. The thermal conductivity efficiency is greatly improved compared with the thermal conductive medium of silicone grease materials in the prior art, and the laser diode is not damaged during the welding process. After the welding is completed, there is no volatile matter, and long-term use will not affect the life of the laser.

[0026] It should be noted that in order to ensure the heat dissipation performance of the entire system and the reliability of welding, the material of the heat sink 13 should be selected from a material with high thermal conductivity, such as copper, and the surface of the heat sink needs to be processed in multiple steps to ensure the reliability of welding, including nickel plating, gold plating, ultrasonic cleaning, alcohol wiping and plasma treatment in sequence. First, nickel plating can prevent copper from oxidizing, and the oxide will become a connection barrier layer of the metal, thereby hindering the welding wetting and causing the formation of cold solder joints; the gold-plated surface can form a smaller wetting angle with the solder, greatly improving the welding performance. Here, nickel plating first and then gold plating can form a nickel dam effect. If gold is directly plated on copper, the gold-plated layer has more pores when the thickness is relatively thin, and copper will diffuse to the surface of the gold-plated layer. After diffusing to the surface of the gold-plated layer, copper is more easily oxidized. Once an oxide film is formed, the good welding performance will be reduced. In addition, from an economic point of view, gold plating cannot be performed on a large area and with high thickness, so it does not play a protective role; ultrasonic cleaning, alcohol wiping and plasma treatment are all to remove the surface oil of the heat sink and increase the surface wettability.

[0027] At least a portion of the water cooling component 20 is in contact with the heat sink 13, and the contact area between the two is further filled with a second solder. The first solder and the second solder are both low-temperature solders, and the thermal conductivity is much higher than that of silicone grease-type thermal conductive materials. In this embodiment, the water cooling component 20 includes a water cooling base plate 21 with a water channel, and a welding plate 22 covering the water channel. The welding plate 22 is in contact with the heat sink 13. Preferably, one end surface of the heat sink with an inner hole is entirely located on the welding plate 22. The second solder guides the heat in the heat sink 13 into the welding plate 22, and heat exchange and heat dissipation are performed through the water channel.

[0028] Figure 4 The preparation process of the water-cooling assembly 20 is shown. First, the water channel is processed on the water-cooling substrate 21, and then the brazing material 23 is filled between the water-cooling substrate 21 and the welding plate 22. The welding plate 22 is welded to the water-cooling substrate 21 using a vacuum brazing furnace. Finally, stir friction welding is used around the welding plate to enhance the strength of the water-cooling structure.

[0029] The present invention also provides a high-power semiconductor laser, which comprises a plurality of laser diodes and a heat dissipation device, wherein the heat dissipation device is used for performing heat dissipation processing on the plurality of laser diodes.

[0030] The present invention also provides an assembly method for the high-power semiconductor laser, which mainly includes a laser diode fixing step and a heat-conducting component and a water-cooling component fixing step.

[0031] Specifically include:

[0032] S1. Insert a first annular solder preform into the inner hole of the heat-conducting component so that the first solder preform fits the inner side surface of the first step.

[0033] like Figure 2 As shown, the structure of the first preformed solder 41 is designed to be annular according to the heat dissipation surface of the laser diode, and the wall thickness is 0.3 mm. A specific operation process is given in this example. First, the first preformed solder 41 is installed one by one in the inner hole 11 of the heat sink 13 using tweezers, so that the outer wall of the first preformed solder 41 is fully fitted with the inner side surface A of the first step 111 of the heat sink.

[0034] S2. The heat-conducting component placed with the inner hole facing upward is heated to the melting point of the first preform solder, so that the first preform solder sequentially wets the inner side surface and the step surface of the first step to form a first solder.

[0035] The specific implementation method is to place the heat sink 13 on a constant temperature heating table so that the temperature of the heat sink reaches the melting point of the first preformed solder. The first preformed solder 41 will wet the inner side surface A of the first step 111 of the heat sink. Due to the capillary effect, the first preformed solder 41 will continue to wet the step surface B of the first step 111. The first preformed solder wets the inner side surface and the step surface to form a first solder.

[0036] S3, installing the laser diode into the inner hole, so that the first solder is filled between the tube base of the laser diode and the first step, and between the tube cap of the laser diode and the second step.

[0037] The specific implementation method is to use tweezers to install the laser diodes 30 one by one on the inner hole 111 of the heat sink 13. After installation, slightly rotate the laser diode so that the two welding surfaces of the laser diode (the side and top surfaces of the tube seat) and the heat sink are fully filled with the first solder to form a multi-sided weld. Both welding surfaces are away from the pins and the packaging glass window to avoid contamination of the laser diode during the welding process. Then, the heat sink is placed at room temperature for a period of time to allow the first solder to solidify naturally.

[0038] S4. Use a second preformed solder to solder the thermal conductive component to the water cooling component.

[0039] like Figure 3 As shown, first place the water-cooling component 20 on a constant temperature heating table so that its temperature reaches the melting point of the second preformed solder 42, place the second preformed solder 42 on the water-cooling component 20, and use a tool to evenly spread it on it; then install the heat sinks assembled in the previous step on the water-cooling component 20 one by one, and before fixing, it is necessary to slide the heat sink slightly so that the space between it and the water-cooling component 20 is fully filled with the second preformed solder 42, then use screws to reinforce the heat sink, and finally place the installed water-cooling component at room temperature to allow the second preformed solder 42 to solidify naturally. It should be noted that in order to avoid damaging the laser diode, the melting points of the first preformed solder and the second preformed solder need to be lower than the tolerable temperature of the laser diode, and the melting point of the first preformed solder is higher than that of the second preformed solder, so as to avoid the first preformed solder melting when welding the heat sink, which may cause the laser diode to fall off.

[0040] The above-described embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A heat dissipation device for a laser diode, characterized in that: include: A heat-conducting component (10) having a plurality of inner holes (11), wherein the inner holes (11) can be welded to the laser diode (30) via a first solder; as well as A water cooling component (20) is in contact with at least a portion of the heat conducting component (10), and the water cooling component (20) is used to dissipate heat from the laser diode absorbed by the heat conducting component (10).

2. The heat dissipation device according to claim 1, characterized in that: The inner hole (11) has a first step (111) matched with the tube seat of the laser diode (30) and a second step (112) matched with the tube cap of the laser diode, and the first solder is filled between the inner side surface (A) of the first step and the step surface (B) and the laser diode.

3. The heat dissipation device according to claim 1 or 2, characterized in that: The heat-conducting component (10) is a plurality of heat sinks (13) placed side by side, and the inner hole (11) is opened at one end of the heat sink close to the water-cooling component (20).

4. The heat dissipation device according to claim 1, characterized in that: A second solder is filled between the water cooling component (20) and the heat conducting component (10).

5. The heat dissipation device according to claim 4, characterized in that: The first solder and the second solder are both low-temperature solder.

6. The heat dissipation device according to claim 1, characterized in that: The water cooling component (20) comprises a water cooling base plate (21) provided with a water channel, and a welding plate (22) covering the water channel, wherein the welding plate (22) is in contact with the heat conducting component (10).

7. A high power semiconductor laser, characterized in that: It comprises a plurality of laser diodes and a heat dissipation device as claimed in any one of claims 1 to 6, wherein the heat dissipation device is used for dissipating heat for the plurality of laser diodes.

8. A method for assembling a high-power semiconductor laser as claimed in claim 7, characterized in that: The steps include: Installing a first annular solder preform into the inner hole of the heat conducting component so that the first solder preform is in contact with the inner side surface of the first step; The heat-conducting component placed with the inner hole facing upward is heated to the melting point of the first preform solder, so that the first preform solder sequentially wets the inner side surface and the step surface of the first step to form a first solder; Installing the laser diode into the inner hole so that the first solder is filled between the tube base of the laser diode and the first step, and between the tube cap of the laser diode and the second step; The thermal conductive component is soldered to the water cooling component using a second preform solder.

9. The assembly method according to claim 8, characterized in that: The heat conduction component is a plurality of heat sinks placed side by side, and the surfaces of the heat sinks are plated with nickel and gold.

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