Heat sink device applied to crystal in solid laser

Abstract

The utility model relates to the technical field of laser crystal cooling, in particular to a heat sink device applied to a crystal in a solid laser, which comprises a heat sink base and a heat sink upper cover which jointly form a transverse through groove, the crystal is inserted in the through groove, and an indium foil layer is covered and adhered on the inner wall of the through groove. The indium foil layer can also be attached to the side wall of the crystal in a surrounding mode, a compression piece is arranged on the heat sink upper cover and compresses the heat sink upper cover downwards, and the compression amount of the compression piece is smaller than the thickness of the indium foil layer. According to the heat sink device applied to the crystal in the solid laser, the contact surface of the crystal and the heat sink is filled with indium without gaps, the side surface of the crystal is uniform in heat conduction, and the crystal is not stressed and does not deform, so that the crystal can bear higher injection power without being damaged; light spot distortion caused by non-uniform temperature distribution and deformation of the clamped crystal in the output laser is avoided, the requirement of the installation process on personnel is not high, and the problem that the crystal is prone to damage in the installation process in the traditional technology is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of laser crystal cooling, in particular to a heat sink device applied to a crystal in a solid laser. Background Art

[0002] Solid-state lasers include lamp-pumped lasers, diode side-pumped lasers, diode end-pumped lasers, fiber lasers, disk lasers, slab lasers and many other types.

[0003] Solid-state lasers generate a lot of heat when working, and it is necessary to perform temperature control on the laser crystal and the frequency-doubling crystal (frequency-doubling crystals are only found in solid-state lasers that use frequency-doubling technology to change the output laser wavelength). There are three common temperature control methods. One is to directly expose the crystal to the air for cooling, which is suitable for solid-state lasers with low heat generation and low temperature control requirements, such as low-power fiber lasers. The second is to immerse the crystal in liquid for cooling, and the liquid circulation takes away the heat, and the liquid temperature is controlled to achieve the purpose of controlling the crystal temperature. This is suitable for solid-state lasers with large heat generation, such as lamp-pumped lasers, diode side-pumped lasers, and high-power fiber lasers. The third is to clamp the crystal in a metal heat sink. The heat sink is usually made of copper with good thermal conductivity. The heat sink is controlled by water or external TEC or external duct fan, so as to achieve the purpose of controlling the crystal temperature, such as diode end-pumped lasers, disk lasers, and solid-state lasers using frequency-doubling technology.

[0004] For the third temperature control method, that is, the method of clamping the crystal in the heat sink, in order to make the heat conduction between the crystal and the heat sink as fast as possible, the contact area between the crystal and the heat sink needs to be increased. The commonly used method in China is to wrap the crystal with indium foil, and then clamp it in the heat sink and press it tightly. Due to the good ductility of indium, most of the gap between the crystal and the heat sink is filled, thereby increasing the contact area between the crystal and the heat sink. However, this method has five problems:

[0005] 1. No matter how good the ductility of indium foil is, it is impossible to fill all the gaps between the crystal and the heat sink;

[0006] 2. The indium foil needs to be pressed as tightly as possible during clamping to fill more gaps, but strong pressure can easily cause the crystal to fracture and damage. The pressure during clamping will inevitably cause the crystal to deform to a certain extent, which will cause the output laser to be distorted. In addition, when the output power is high, the crystal may rupture due to thermal expansion and contraction under pressure.

[0007] 3. The clamping force of the contact surfaces between the crystal and the heat sink in different directions is difficult to be consistent, resulting in different contact conditions in different directions of the crystal, different heat conduction and heat dissipation speeds, and different temperature distributions in different directions of the crystal;

[0008] 4. The heat sink is generally designed to consist of two parts: a heat sink cover and a heat sink base. If the indium foil at the contact surface between the crystal and the heat sink is pressed, there will often be a large gap between the indium foil at the contact surface between the heat sink cover and the heat sink base. This will result in poor heat conduction between the heat sink cover and the heat sink base, and a large temperature difference will occur between the crystal surface in contact with the heat sink cover and the crystal surface in contact with the heat sink base.

[0009] These problems make the crystal easy to be damaged, the output laser has large distortion, the beam quality deteriorates, and at the same time place high demands on the crystal clamping and assembly workers. Utility Model Content

[0010] Based on the above description, the utility model provides a heat sink device applied to a crystal in a solid laser to solve the deficiencies in the prior art.

[0011] The technical solution of the utility model to solve the above technical problems is as follows:

[0012] A heat sink device for a crystal in a solid-state laser, comprising:

[0013] Heat sink base;

[0014] A heat sink upper cover, which is disposed on the heat sink base and forms a transverse through groove together with the heat sink base;

[0015] a crystal, disposed in the through groove;

[0016] An indium foil layer is attached to the inner wall of the through groove and surrounds and wraps the crystal;

[0017] A compression member compresses the heat sink cover downward, and the compression amount is less than the thickness of the indium foil layer.

[0018] On the basis of the above technical solution, the present invention can also be improved as follows.

[0019] Furthermore, a heating furnace is connected to the bottom of the heat sink base.

[0020] Furthermore, the length of the crystal is greater than the through slot, and an external indium foil is sleeved on the protruding portion of the crystal extending out of the through slot, and the external indium foil is respectively connected to the heat sink upper cover and the heat sink base.

[0021] Furthermore, a screw hole with a depth reaching the inside of the heat sink base is opened on the top surface of the heat sink upper cover, a screw is threadedly connected to the screw hole, a spring is sleeved on the screw, and the spring applies an upward elastic force to the screw.

[0022] Compared with the prior art, the technical solution of this application has the following beneficial technical effects:

[0023] This solution provides a heat sink device for crystals in solid-state lasers. The contact surface between the crystal and the heat sink is filled with indium without a gap. The side of the crystal conducts heat evenly. The crystal is not subjected to force and does not deform, so that the crystal can withstand a larger injection power without damage. The output laser no longer has spot distortion caused by uneven temperature distribution and deformation of the crystal in the clamping. The installation process does not require high personnel requirements, eliminating the problem of easy damage to the crystal during installation with traditional technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A structural front view of a heat sink device for a crystal in a solid-state laser provided by an embodiment of the utility model;

[0025] Figure 2 for Figure 1 Side view of

[0026] Figure 3 It is a front view of another embodiment of the utility model;

[0027] Figure 4 for Figure 3 Side view of

[0028] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0029] 1. Heat sink base; 2. Heat sink cover; 3. Indium foil layer; 4. Heating furnace; 5. Screws; 6. Springs; 7. Crystal; 8. Clamp. DETAILED DESCRIPTION

[0030] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0032] It will be appreciated that spatial relationship terms such as "under," "beneath," "below," "under," "above," "above," etc., may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It will be appreciated that, in addition to the orientations shown in the figures, spatial relationship terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0033] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element, or connected to the other element through an intermediate element. The "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0034] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof.

[0035] like Figure 1-4 A heat sink device for a crystal 7 in a solid-state laser is shown, comprising a heat sink base 1 and a heat sink upper cover 2, wherein the heat sink upper cover 2 is covered on the heat sink base 1 and forms a transverse through groove together with the heat sink base 1, wherein the crystal 7 is inserted in the through groove, and an indium foil layer 3 is covered and attached to the inner wall of the through groove, and the indium foil layer 3 can also be attached around the side wall of the crystal 7, and in order to fix the crystal 7, a force needs to be applied between the heat sink upper cover 2 and the heat sink base 1, and a compression member is provided on the heat sink upper cover 2, which compresses the heat sink upper cover 2 downward, and the compression amount is less than the thickness of the indium foil layer 3, and specifically, a screw hole with a depth reaching the inside of the heat sink base 1 is opened on the top surface of the heat sink upper cover 2, and a screw 5 is threadedly connected to the inner thread of the screw hole, and a spring 6 is sleeved on the screw 5, and the spring 6 applies an upward elastic force to the screw 5, and the compression amount of the spring 6 is less than the thickness of the indium foil layer 3. The bottom of the heat sink base 1 is connected to a heating furnace 4 for heating the heat sink base 1 . The heat of the heat sink base 1 is transferred to the heat sink cover 2 and the indium foil layer 3 inside, so that the indium foil layer 3 melts and fills the gap between the crystal 7 and the through groove.

[0036] This scheme provides two embodiments for explanation. In the first embodiment, the length of the crystal 7 is almost equal to the length of the through-slot, slightly longer or shorter (generally not more than 2 mm). When it is longer, the protruding part does not need to be wrapped with indium foil. In the second embodiment, the length of the crystal 7 is significantly longer than the through-slot. The protruding part of the crystal 7 extending out of the through-slot is sleeved with an external indium foil, which is respectively connected to the heat sink cover 2 and the heat sink base 1. After heating, the external indium foil of the crystal 7 extending out of the through-slot is melted by heat conduction and tightly wrapped with the crystal 7. In the two embodiments, the two end faces of the crystal 7 do not need to be wrapped with indium foil. The two end faces correspond to the light input and output respectively. When installing the crystal 7 and during the heating process, the clamp 8 is required to clamp the two end faces of the crystal 7 to prevent the crystal 7 from sliding relative to the through-slot under the pressure of the spring 6.

[0037] Embodiment 1:

[0038] Reference Figure 1 , Figure 2 , the length of crystal 7 is shorter than that of the heat sink, and the typical value of the length difference is 0.4mm to 2mm; a layer of indium foil is wrapped on the side of crystal 7, the length of indium foil is shorter than that of crystal 7, and a section of crystal 7 is exposed at both ends without being wrapped with indium foil, and the typical length of each exposed section at both ends is 0.2mm to 1mm; the crystal 7 wrapped with indium foil is placed between the heat sink cover 2 and the heat sink base 1; a layer of indium foil is padded on the contact surface of the heat sink cover 2 and the heat sink base 1, the size of the indium foil is consistent with the size of the contact surface in the through groove, the indium foil is in a flat state, and each corresponding surface has sufficient surface contact with the indium foil. Two screws 5 and two matching spring washers (a combination of springs 6 and washers) are used to pass through the two through holes on the heat sink cover 2 and fixed to the two screw holes on the heat sink base 1. The spring washers have a compression amount, but the compression amount is less than the thickness of the indium foil. The device is placed on the heating furnace 4 as a whole. The heating furnace 4 is slowly heated to above the melting point of indium (157 degrees Celsius). The time required to heat from 25 degrees Celsius to 157 degrees Celsius is typically 30 minutes to 60 minutes. The indium foil melts, the spring washers release the pressure and return to a non-compressed state, causing liquid indium to flow and fill the gaps in all contact surfaces of the crystal 7, the heat sink cover 2 and the heat sink base 1. Since the compression amount of the spring washers is less than the thickness of the indium foil, the liquid indium on each contact surface will not be completely squeezed out, and the crystal 7 will not be deformed. Since the length of the crystal 7 is longer than the heat sink, the liquid indium will not flow to the end face of the crystal 7. The heating furnace 4 is closed, the crystal 7 and the heat sink are slowly cooled, and the liquid indium solidifies, completing the indium welding process.

[0039] Embodiment 2:

[0040] See also Figure 3 , Figure 4, wrap a layer of indium foil on the side of the crystal 7, the length of the indium foil is consistent with that of the crystal 7, and place the crystal 7 wrapped with indium foil between the heat sink cover 2 and the heat sink base 1; pad the contact surface of the heat sink cover 2 and the heat sink base 1 with a layer of indium foil, the size of the indium foil is consistent with the size of the contact surface, the indium foil is in a flat state, and each corresponding surface has sufficient surface contact with the indium foil; use two screws 5 and two matching spring washers to pass through the two through holes on the heat sink cover 2 and fix them to the two screw holes on the heat sink base 1, the spring washer group has a compression amount, but the compression amount is less than the thickness of the indium foil; clamp the end face springs 6 of the crystal 7 at both ends of the crystal 7, and the two end face pads are in seamless and complete contact with the two end faces of the crystal 7. The device is placed on a heating furnace 4, which is slowly heated to a temperature above the melting point of indium (157 degrees Celsius). The time required to heat up from 25 degrees Celsius to 157 degrees Celsius is typically 30 minutes to 60 minutes. The indium foil melts, the spring pad group releases pressure, and returns to a non-compressed state, causing liquid indium to flow and fill the gaps in all contact surfaces of the crystal 7, the heat sink cover 2, and the heat sink base 1. Since the compression of the spring pad group is less than the thickness of the indium foil, the liquid indium on each contact surface will not be completely squeezed out, and the crystal 7 will not be deformed. Due to the spring 6 clamp on the end face of the crystal 7, the liquid indium will not flow to the end face of the crystal 7. The heating furnace 4 is closed, the crystal 7 and the heat sink are slowly cooled, the liquid indium solidifies, and the spring 6 clamp on the end face of the crystal 7 is removed to complete the indium welding process.

[0041] In the above embodiment, the crystal 7 can be Nd:YAG (neodymium-doped yttrium aluminum garnet), Nd:YVO4 (neodymium-doped yttrium vanadate), KTP (potassium titanyl phosphate), LBO (lithium triborate), BBO (barium metaborate crystal 7), any other crystal 7 that can generate laser, or any other crystal 7 that can generate frequency doubling effect; the shape of the crystal 7 can be a rectangular parallelepiped, a cylinder, or any shape that can generate laser; in order to make the welding effect more reliable, the side of the crystal 7 can be gold-plated, or Silver plating can be done by any process that can improve welding strength; the heat sink material can be copper, brass, or any metal with good thermal conductivity; the heat sink surface can be gold-plated, can be gold-plated, can use any anti-oxidation process, can use any process that improves thermal conductivity, can use any process that improves welding strength; the material used for welding can be indium foil, can be indium tin alloy, can be any material that can weld crystal 7 and metal; the number of screws 5 used for fixing can be 1, can be 2, can be 4, or can be any practical design.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A heat sink device for a crystal in a solid-state laser, characterized in that: include: Heat sink base; A heat sink upper cover, which is disposed on the heat sink base and forms a transverse through groove together with the heat sink base; a crystal, disposed in the through groove; An indium foil layer is attached to the inner wall of the through groove and surrounds and wraps the crystal; A compression member compresses the heat sink cover downward, and the compression amount is less than the thickness of the indium foil layer.

2. A heat sink device for a crystal in a solid-state laser according to claim 1, characterized in that: The bottom of the heat sink base is connected with a heating furnace.

3. The heat sink device for a crystal in a solid-state laser according to claim 1, characterized in that: The length of the crystal is greater than the through slot, and an external indium foil is sleeved on the protruding portion of the crystal protruding from the through slot, and the external indium foil is respectively connected to the heat sink upper cover and the heat sink base.

4. A heat sink device for a crystal in a solid laser according to claim 1 or 3, characterized in that: A screw hole with a depth reaching the inside of the heat sink base is opened on the top surface of the heat sink upper cover, a screw is threadedly connected to the screw hole, a spring is sleeved on the screw, and the spring applies an upward elastic force to the screw.

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