A combined base plate structure and heat dissipation method for a laser

Abstract

The application provides a combined bottom plate structure of a laser, which is a multi-layer plate integrated structure fixedly connected to the bottom of the inner cavity of the laser, comprising a support plate, a semiconductor refrigerator, a heat insulation pad, a base plate and a mounting plate; the bottom surface of the support plate is fixedly connected to the bottom of the inner cavity of the laser shell; the semiconductor refrigerator and the heat insulation pad form a first square body structure, the bottom surface of the first square body structure is connected to the top surface of the support plate; the mounting plate and the base plate form a second square body structure; the bottom surface of the second square body structure is connected to the top surface of the first square body structure, and the top surface of the second square body structure is an optical platform for bearing a plurality of optical components and absorbing heat. The application also provides a heat dissipation method for the combined bottom plate structure of the laser. The application solves the technical problem that the bottom plate structure of the existing laser cannot simultaneously meet the requirements of high-efficiency heat dissipation, accurate temperature control and stable structure due to the single material.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and specifically to a combined base plate structure and heat dissipation method for a laser. Background Technology

[0002] The operational stability of a laser directly depends on the precision of its internal component mounting and thermal environment control. The laser's base plate structure, as the direct support and positioning basis for its internal optical components, is a core component ensuring the laser's cavity closure precision and stable operating temperature. During laser operation, its internal optical components continuously generate heat. Localized heat accumulation can easily lead to temperature drift and thermal stress deformation, resulting in fluctuations in laser output power and a decrease in beam quality. Therefore, how the base plate structure can quickly conduct and dissipate heat to achieve precise temperature control in the core area is a key technical problem that needs to be solved. Furthermore, the closed-loop optical path inside the laser cavity requires micron-level precision in component spacing and mounting angles. How the base plate structure can withstand deformation caused by assembly stress and environmental temperature fluctuations, ensuring long-term stability of the optical reference and preventing optical path drift, is another technical problem that needs to be addressed.

[0003] Existing laser base plate structures, such as the laser resonator and heat dissipation method disclosed in Chinese patent document CN119481897A that enhances the heat dissipation performance of the gain medium, employ heat pipe components to enhance heat dissipation. However, this solution is difficult to manufacture, expensive, and its application scenarios are limited. Furthermore, this solution only addresses the heat dissipation efficiency issue and does not address the optimization of the base plate structure's stability. It cannot provide a high-precision mounting reference for the annular cavity mirror, nor can it achieve precise temperature control of the base plate, making it unsuitable for the stringent requirements of small lasers. It is evident that existing laser base plate structures cannot simultaneously meet the integrated requirements of efficient heat dissipation, precise temperature control, and structural stability, becoming a key bottleneck restricting the long-term stable operation and miniaturization of lasers. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a combined base plate structure for lasers and a heat dissipation method. Through its layered structure of lower support and heat dissipation, middle temperature control and heat conduction, and upper load-bearing and shape stabilization, the laser ensures the installation accuracy and temperature stability of optical components, and the annular optical path continuously and stably locks the cavity. This solves the technical problem that existing laser base plate structures, due to their single material, cannot simultaneously meet the laser's requirements for efficient heat dissipation, precise temperature control, and structural stability.

[0005] The technical solution of the present invention is as follows:

[0006] A combined base plate structure for a laser, the combined base plate structure being a multi-layer plate integral structure fixedly connected to the bottom of the laser cavity, comprising:

[0007] The lower support plate has its bottom surface fixedly connected to the bottom of the inner cavity of the laser housing and is used to transfer heat to the laser housing.

[0008] The semiconductor cooler and the heat insulation pad are located in the middle layer. The semiconductor cooler is embedded into the heat insulation pad from one side of the heat insulation pad to form a first square structure for temperature control. The bottom surface of the first square structure is attached to the top surface of the support plate and is used to transfer heat to the support plate.

[0009] The upper base plate and mounting plate are embedded in the base opening of the base plate to form a second square structure for absorbing heat from the heat source. The first and second protrusions at the bottom of the base opening near the middle are respectively embedded in the opening of the mounting plate. The bottom surface of the second square structure is attached to the top surface of the first square structure and is used to conduct heat to the first square structure. Its top surface is an optical platform for supporting multiple optical components and absorbing heat.

[0010] Preferably, the optical platform includes a base plate top surface located on the left side of the top surface of the second square body, a first protruding top surface and a second protruding top surface located in the middle, and a mounting plate top surface located in the middle and right sides; the base plate top surface, the first protruding top surface and the second protruding top surface are all set as mounting areas for optical components to be dissipated; the base plate top surface, the mounting plate top surface, the first protruding top surface and the second protruding top surface are on the same horizontal plane.

[0011] This invention achieves precise positioning and fitting of the mounting plate and the base plate by embedding the first and second protrusions into the first and second openings of the mounting plate, limiting the displacement of the mounting plate and preventing it from shifting due to vibration or thermal expansion and contraction after assembly, thus ensuring the stability of the optical reference. Furthermore, the top surfaces of the first and second protrusions serve as the mounting areas for the laser crystal and the frequency doubling crystal, respectively. The laser crystal holder and the frequency doubling crystal holder are then fixed through threaded holes, providing independent mounting areas for the laser crystal and the frequency doubling crystal. This directly transfers the heat generated by the laser crystal and the frequency doubling crystal to the base plate, shortening the heat transfer path and improving heat dissipation efficiency.

[0012] Preferably, one side of the heat insulation pad has a square opening along its length that matches the shape of the thermoelectric cooler, and the thermoelectric cooler is embedded in the square opening with its two adjacent sides fitting against the inner side of the square opening.

[0013] The base plate has a base opening on its right side along the height direction, which is adapted to the shape of the mounting plate. The first protrusion is located at the rear center of the base opening, and the second protrusion is located at the front center of the base opening. The bottom surface of the base plate has a square groove along its height direction that is adapted to the shape of the thermoelectric cooler. The thermoelectric cooler is vertically embedded into the square groove, and the top surface of the thermoelectric cooler is in contact with the top wall of the square groove.

[0014] The mounting plate has openings including a first opening and a second opening, and the first opening and the second opening are respectively adapted to the shape of the first protrusion and the shape of the second protrusion; the mounting plate is inserted into the base opening of the base plate from the top surface of the base plate along its height direction, and the first opening and the second opening are respectively matched with the first protrusion and the second protrusion.

[0015] Preferably, the mounting areas for the multiple optical components include a pump source mounting area disposed on the top surface of the base plate, a laser crystal mounting area disposed on the top surface of the first protrusion, and a frequency doubling crystal mounting area disposed on the top surface of the second protrusion.

[0016] The laser crystal mounting area has a first mirror mounting area and a second mirror mounting area on its left and right sides, and the frequency doubling crystal mounting area has a third mirror mounting area and a fourth mirror mounting area on its left and right sides.

[0017] The first mirror mounting area is located between the pump source mounting area and the laser crystal mounting area. The third mirror mounting area is located directly in front of the first mirror mounting area, and the fourth mirror mounting area is located directly in front of the second mirror mounting area.

[0018] Preferably, a first optical path reflection point is provided in the first reflector mounting area, a second optical path reflection point is provided in the second reflector mounting area, a third optical path reflection point is provided in the third reflector mounting area, and a fourth optical path reflection point is provided in the fourth reflector mounting area.

[0019] A first reflected optical path connecting line is formed between the first optical path reflection point and the fourth optical path reflection point; a second reflected optical path connecting line is formed between the second optical path reflection point and the third optical path reflection point; and a third reflected optical path connecting line is formed between the third optical path reflection point and the fourth optical path reflection point. The angle α between the first and third reflected optical path connecting lines and the angle β between the second and third reflected optical path connecting lines are both within the range of 23 degrees to 27 degrees.

[0020] Preferably, the top surface of the semiconductor cooler is covered with thermally conductive silicone grease, and the top surface of the semiconductor cooler is attached to the top wall of the square groove on the bottom surface of the base plate by the thermally conductive silicone grease.

[0021] The semiconductor cooler is connected to both a built-in temperature sensor and an external temperature control module.

[0022] Preferably, the support plate is made of aluminum alloy, the heat insulation pad is made of non-metallic material, the base plate is made of pure copper, and the mounting plate is made of Invar steel.

[0023] Preferably, the thermal conductivity of pure copper is greater than or equal to 390 W / (m·K), and the coefficient of linear expansion of Invar is less than or equal to 1.5 × 10⁻⁻⁻⁶. 6 / ℃, the tensile strength of the aluminum alloy is greater than or equal to 210MPa.

[0024] In this invention, the base plate located on the upper layer serves as the core heat-conducting component, directly supporting heat-generating components such as the LD pump source, laser crystal, and frequency doubling crystal. It utilizes its high thermal conductivity to rapidly absorb the heat generated by the components and evenly diffuses it through lateral thermal conductivity, eliminating localized hot spots. A square groove is formed at the bottom to fit against the cold surface of the semiconductor cooler, transferring the absorbed heat to the semiconductor cooler. It can be seen that the base plate in this invention not only efficiently dissipates heat from the core components, reducing thermal deformation caused by thermal gradients and preventing performance degradation due to localized overheating, but also provides a flat and stable mounting reference for the heat-generating components, ensuring accurate device positioning.

[0025] In this invention, the mounting plate located on the upper layer is embedded in the base opening of the base plate and positioned by the cooperation of the first protrusion, the second protrusion and its own opening. It fits into the base plate to form a coplanar first square structure, which ensures the consistency of the mounting reference for optical components and can also offset the thermal deformation of the pure copper base plate, ensuring the long-term stability of the optical platform. The top surface is provided with mounting areas for the first to fourth reflectors, and the reflector frames are fixed by threaded holes, providing a dimensionally stable mounting reference for the reflectors in the annular cavity of the laser, ensuring that the spacing fluctuation between the first to fourth reflectors is less than or equal to 0.5μm, and avoiding optical path drift.

[0026] In this invention, the semiconductor cooler located in the middle layer serves as the core component for active temperature control. Its top surface is bonded to the base plate with thermally conductive silicone grease, absorbing the heat transferred from the base plate. Its bottom hot surface is bonded to the support plate, conducting the absorbed heat to the support plate, thereby achieving active temperature control of the base plate and stabilizing the temperature within ±0.01℃ of the set value, ensuring that devices such as laser crystals and frequency doubling crystals operate within the optimal temperature range. It forms a closed-loop control circuit with the temperature sensor and PID temperature control module, receiving the current adjustment signal from the PID temperature control module and achieving precise control of the cooling power by changing the magnitude and direction of the current.

[0027] In this invention, the heat insulation pad located in the middle layer is arranged around the semiconductor cooler and embedded between the support plate and the base plate, covering the non-contact area between the two. Utilizing the characteristic of low thermal conductivity, it blocks the reverse heat transfer path between the support plate and the base plate, ensuring that the temperature stability of the base plate is not affected by the temperature fluctuation of the support plate, avoiding "ineffective cooling" of the temperature control system, and ensuring temperature control accuracy. In addition, it is embedded with the semiconductor cooler to form a first square structure, which helps to position the semiconductor cooler and prevent it from shifting.

[0028] In this invention, the support plate located at the bottom layer serves as the basic load-bearing component of the combined base plate. Its bottom is rigidly connected to the laser housing, and its top is in contact with the hot surface of the semiconductor cooler, thus constructing a heat transfer channel from the semiconductor cooler to the support plate and the laser housing. This efficiently transfers the heat released by the semiconductor cooler, which is then dissipated through natural convection within the housing, completing the heat dissipation closed loop.

[0029] This invention also provides a heat dissipation method for a combined base plate structure of a laser, applied to a combined base plate structure of a laser, comprising the following steps:

[0030] Heat absorption step: Multiple optical components of the laser are fixedly mounted on the optical platform. The pure copper base plate quickly absorbs the heat generated when the optical components are working, and then the heat is evenly diffused through its lateral thermal conductivity and transferred to the semiconductor cooler in the middle layer.

[0031] Heat transfer and active temperature control steps: By using the top surface of the thermoelectric cooler as its cold surface and tightly adhering it to the bottom surface of the base plate, the cold surface receives heat from the base plate. Conversely, by using the bottom surface of the thermoelectric cooler as its hot surface and tightly adhering it to the top surface of the support plate, the hot surface transfers heat to the support plate. Simultaneously, a temperature sensor collects the real-time temperature signal of the base plate and feeds it back to the PID temperature control system. The PID temperature control system performs active closed-loop temperature control on the base plate, keeping its temperature within the set range.

[0032] Heat export and dissipation steps: The support plate receives the heat released from the hot surface of the semiconductor cooler, and then conducts the heat to the laser housing through the connection structure between the support plate and the laser housing;

[0033] Reverse thermal insulation step: By using thermal insulation pads to thermally insulate the support plate from the base plate, the heat from the support plate is prevented from being conducted back to the base plate.

[0034] Preferably, in the heat absorption step, multiple optical components of the laser are respectively fixedly mounted on an optical platform, including the following steps:

[0035] The pump source, laser crystal, frequency doubling crystal, first reflector, second reflector, third reflector, and fourth reflector of the laser are respectively fixedly installed in the pump source installation area, laser crystal installation area, frequency doubling crystal installation area, first reflector installation area, second reflector installation area, third reflector installation area, and fourth reflector installation area of ​​the optical platform.

[0036] The technical effects of this invention are as follows:

[0037] This invention forms a three-layer integrated structure for the bottom plate of the laser cavity through a lower high-strength aluminum alloy support plate, a middle semiconductor cooler and heat insulation pad, an upper high thermal conductivity pure copper base plate, and a low expansion Invar steel mounting plate. This structure also features a three-layer functional hierarchy: lower layer for support and heat dissipation, middle layer for temperature control and heat conduction, and upper layer for load bearing and stability. This ensures the laser's precision in mounting optical components and temperature stability, maintains continuous and stable cavity locking in the annular optical path, achieves peak-to-peak stability of laser output power better than 0.8%, and improves frequency doubling conversion efficiency by ≥5%. This invention solves the technical problem that existing laser base plate structures, due to their single material, cannot simultaneously meet the laser's requirements for efficient heat dissipation, precise temperature control, and structural stability.

[0038] This invention achieves active closed-loop temperature control of the base plate by vertically embedding a semiconductor cooler into a square groove on the bottom surface of the base plate, with the top surface of the semiconductor cooler abutting against the top wall of the square groove, and by communicating with the semiconductor cooler to a built-in temperature sensor and temperature control module, with the temperature sensor abutting against the pure copper base plate. The temperature control accuracy reaches ±0.01℃, ensuring that the temperature gradient at different locations on the base plate is ≤±0.03℃, thus improving the laser's resistance to ambient temperature fluctuations.

[0039] This invention forms a second square structure by interlocking a pure copper base plate with an Invar steel mounting plate. A pump source mounting area is provided on the top surface of the base plate, a laser crystal mounting area is provided on the top surface of the first protrusion, and a frequency doubling crystal mounting area is provided on the top surface of the second protrusion. First to fourth mirror mounting areas are provided on the mounting plate. Heat generated by the laser crystal, frequency doubling crystal, and pump source in the pump source and frequency doubling crystal mounting areas is dissipated by the base plate. The deformation-sensitive first to fourth mirror mounting areas are located on the Invar steel mounting plate, effectively avoiding thermal stress deformation caused by the thermal gradient of the base plate. The flatness variation of the mounting plate is ≤1μm, and the spacing fluctuation between the first, second, third, and fourth mirrors is ≤0.5μm, ensuring the stability of the optical reference of the optical devices within the first to fourth mirror mounting areas.

[0040] 4. In this invention, in response to the stringent requirements on the spacing and angle between the first, second, third, and fourth reflectors within the annular cavity of the laser, the invention first achieves the purpose of ensuring both heat dissipation efficiency and providing a dimensionally stable mounting reference by fitting the base plate and the mounting plate together, and then placing the top surface of the base plate, the top surface of the mounting plate, the top surface of the first protrusion, and the top surface of the second protrusion on the same horizontal plane. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of a combined base plate structure for a laser according to an embodiment of the present invention;

[0042] Figure 2 for Figure 1 explosion Figure 1 ;

[0043] Figure 3 for Figure 1 explosion Figure 2 ;

[0044] Figure 4 This is a front view of the combined base plate structure installed inside the laser housing;

[0045] Figure 5 This is a schematic diagram of the structure of an optical platform equipped with optical components;

[0046] Figure 6 This is a flowchart of a heat dissipation method for a combined base plate structure of a laser according to an embodiment of the present invention;

[0047] In the attached diagram, 1-support plate, 2-semiconductor cooler, 3-heat insulation pad, 3-1-square opening, 4-base plate, 4-1-base opening, 4-2-square groove, 5-mounting plate, 5-1-first opening, 5-2-second opening, 6-first protrusion, 7-second protrusion, 8-optical platform, 8-1-top surface of base plate, 8-2-top surface of first protrusion, 8-3-top surface of second protrusion, 8-4-top surface of mounting plate, 9-1-pump source mounting area, 9-2-laser crystal mounting area, 9-3-frequency doubling crystal. Installation area, 9-4-First reflector installation area, 9-5-Second reflector installation area, 9-6-Third reflector installation area, 9-7-Fourth reflector installation area, 10-1-First optical path reflection point, 10-2-Second optical path reflection point, 10-3-Third optical path reflection point, 10-4-Fourth optical path reflection point, 11-1-First reflector, 11-2-Second reflector, 11-3-Third reflector, 11-4-Fourth reflector, 11-5-Pump source, 11-6-Laser crystal, 11-7-Frequency doubling crystal. Detailed Implementation

[0048] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0049] As attached Figure 1 and attached Figure 2 As shown, a combined base plate structure for a laser is a multi-layer plate integral structure fixedly connected to the bottom of the laser cavity, including a support plate 1 located in the lower layer, a semiconductor cooler 2 and a heat insulation pad 3 located in the middle layer, and a base plate 4 and a mounting plate 5 located in the upper layer.

[0050] The bottom surface of the support plate 1 is fixedly connected to the bottom of the inner cavity of the laser. The support plate 1 is made of Al-Mg-Si forged aluminum alloy. The tensile strength of the aluminum alloy is greater than or equal to 210MPa, which can support the weight of the middle semiconductor cooler 2, the upper base plate 4, and the mounting plate 5, ensuring the stability of the support. The yield strength is greater than or equal to 170MPa, which can resist assembly stress such as screw tightening and thermal stress, avoiding deformation. The thermal conductivity is 155-180W / (m·K), which meets the heat dissipation requirements of transferring heat from the semiconductor cooler 2 to the laser housing. As the load-bearing foundation of the entire combined structure, the support plate 1 undertakes the functions of supporting the upper structure and connecting with the laser housing.

[0051] The semiconductor cooler 2 is embedded into the heat insulation pad 3 from one side of the heat insulation pad 3 to form a first square structure with the heat insulation pad 3. The bottom surface of the first square structure is attached to the top surface of the support plate 1 and is used to transfer heat to the support plate 1.

[0052] Preferably, one side of the heat insulation pad 3 has a square opening 3-1 along its length that is adapted to the shape of the semiconductor cooler 2. The semiconductor cooler 2 is embedded in the square opening 3-1 and its two adjacent sides are in contact with the inner side of the square opening 3-1.

[0053] As attached Figure 3 As shown, the top surface of the thermoelectric cooler 2 is covered with thermally conductive silicone grease, and the top surface of the thermoelectric cooler 2 is attached to the top wall of the square groove 4-2 on the bottom surface of the base plate 4 through the thermally conductive silicone grease; the thermoelectric cooler 2 is connected to the built-in temperature sensor through an external temperature control module.

[0054] In this embodiment, the heat insulation pad 3 is a non-metallic material with low thermal conductivity, specifically polytetrafluoroethylene, with a thermal conductivity ≤0.2W / (m・K). A square opening 3-1 is made at the middle position along the length of the heat insulation pad 3, and the square opening 3-1 is precisely matched with the outer dimensions of the semiconductor cooler 2. The semiconductor cooler 2 is a high-power semiconductor cooler 2 with a maximum cooling capacity ≥120W and a temperature control accuracy of ±0.01℃.

[0055] In this embodiment, during the mid-layer assembly, the thermoelectric cooler 2 is first inserted into one side of the square opening 3-1 of the heat insulation pad 3, so that the two adjacent sides of the thermoelectric cooler 2 are tightly fitted with the inner side of the square opening 3-1 to form a first square structure with a gap of ≤0.1mm. Then, the bottom surface of the first square structure is fitted and connected to the top surface of the support plate 1. The area between the bottom surface of the thermoelectric cooler 2, that is, the hot surface of the thermoelectric cooler 2, and the top surface of the support plate 1 is cleaned with anhydrous ethanol and then coated with thermal grease with a thickness of 0.1-0.2mm to ensure heat transfer efficiency. The bottom surface of the heat insulation pad 3 is directly fitted to the top surface of the support plate 1.

[0056] In this embodiment, the base plate 4 is made of pure copper, which has a thermal conductivity greater than or equal to 390 W / (m·K), and the mounting plate 5 is made of Invar steel, which has a coefficient of linear expansion less than or equal to 1.5 × 10⁻⁻⁻⁶. 6 / ℃. The base opening 4-1 on the top surface of the base plate 4 is opened along the height direction on the right side and is adapted to the shape of the mounting plate 5. The first protrusion 6 is located at the rear center of the base opening 4-1, and the second protrusion 7 is located at the front center of the base opening 4-1. The bottom surface of the base plate 4 is provided with a square groove 4-2 adapted to the shape of the semiconductor cooler 2 along its height direction. The top wall of the square groove 4-2 is ground and the roughness Ra≤0.5μm. The openings of the mounting plate 5 include a first opening 5-1 and a second opening 5-2, and the first opening 5-1 and the second opening 5-2 are adapted to the shapes of the first protrusion 6 and the second protrusion 7 of the base plate 4, respectively.

[0057] In this embodiment, during the upper layer fitting assembly, the first protrusion 6 and the second protrusion 7, which are located near the middle part of the bottom of the base opening 4-1 on the top surface of the base plate 4, are respectively embedded into the opening of the mounting plate 5; the mounting plate 5 is embedded into the base opening 4-1 of the base plate 4 from the top surface of the base plate 4 along its height direction, and the first opening 5-1 and the second opening 5-2 respectively cooperate with the first protrusion 6 and the second protrusion 7 to ensure that the top surface of the mounting plate 5 is flush with the top surface of the protrusion. Thus, the mounting plate 5 is embedded into the base opening 4-1 of the base plate 4 and forms a second square body structure with the base plate 4. Meanwhile, the semiconductor cooler 2 is vertically embedded in the square groove 4-2, and the top surface of the semiconductor cooler 2 is in contact with the top wall of the square groove 4-2. The top wall of the square groove 4-2 on the bottom surface of the base plate 4 is coated with thermal grease with a thickness of 0.1-0.2mm, which is in close contact with the top surface (cold surface) of the semiconductor cooler 2, and the contact pressure is controlled at 0.5-1MPa.

[0058] The bottom surface of the second square structure is attached to the top surface of the first square structure. Its top surface is an optical platform 8, which is used to support the optical components to be cooled. The optical platform 8 includes a base plate top surface located on the left side of the top surface of the second square structure, a first protruding top surface and a second protruding top surface located in the middle, and mounting plate top surfaces located in the middle and right. The base plate top surface, the mounting plate top surface, the first protruding top surface, and the second protruding top surface are all on the same horizontal plane. After precision grinding, the coplanarity error of each area is ≤0.3μm, and the surface flatness is ≤1μm, which meets the high-precision installation requirements of optical components.

[0059] As attached Figure 4 As shown, in this embodiment, when dividing the mounting area of ​​the optical platform 8, the top surface 8-1 of the base plate, the top surface 8-2 of the first protrusion, and the top surface 8-3 of the second protrusion are all set as mounting areas for optical components to be cooled; preferably, the mounting area for the optical components to be cooled includes a pump source mounting area 9-1 set on the top surface 8-1 of the base plate, a laser crystal mounting area 9-2 set on the top surface 8-2 of the first protrusion, and a frequency doubling crystal mounting area 9-3 set on the top surface 8-3 of the second protrusion; the laser crystal mounting area 9-1... The first mirror mounting area 9-4 and the second mirror mounting area 9-5 are provided on the left and right sides of the mounting area 9-2. The third mirror mounting area 9-6 and the fourth mirror mounting area 9-7 are provided on the left and right sides of the frequency doubling crystal mounting area 9-3. The first mirror mounting area 9-4 is located between the pump source mounting area 9-1 and the laser crystal mounting area 9-2. The third mirror mounting area 9-6 is located directly in front of the first mirror mounting area 9-4. The fourth mirror mounting area 9-7 is located directly in front of the second mirror mounting area 9-5.

[0060] Two M2 threaded holes are provided in the pump source mounting area 9-1 for fixing the LD pump source heat sink. Two M2 threaded holes are provided in the laser crystal mounting area 9-2 for fixing the laser crystal holder. Two M2 threaded holes are provided in the frequency doubling crystal mounting area 9-3 for fixing the frequency doubling crystal holder. Two M2 threaded holes are provided in the first mirror mounting area 9-4, the second mirror mounting area 9-5, the third mirror mounting area 9-6, and the fourth mirror mounting area 9-7 for fixing the mirrors.

[0061] As attached Figure 5 As shown, pump source 11-5, laser crystal 11-6, frequency doubling crystal 11-7, first reflector 11-1, second reflector 11-2, third reflector 11-3, and fourth reflector 11-4 are respectively mounted on optical platform 8. Pump light of a specific wavelength is output from pump source 11-5 and passes sequentially through first reflector 11-1, laser crystal, second reflector 11-2, third reflector 11-3, frequency doubling crystal 11-7, fourth reflector 11-4, and first reflector 11-1 to form a laser optical path. When designing the optical path reflection points of optical platform 8, the first optical path reflection point 10-1 is set in the first reflector mounting area 9-4, the second optical path reflection point 10-2 is set in the second reflector mounting area 9-5, and the third reflector mounting area 9-4 is set in the fourth reflector mounting area 9-5. A third optical path reflection point 10-3 is provided in area 9-6, and a fourth optical path reflection point 10-4 is provided in area 9-7, where the fourth reflector is installed. A first reflected optical path connecting line is formed between the first optical path reflection point 10-1 and the fourth optical path reflection point 10-4. A second reflected optical path connecting line is formed between the second optical path reflection point 10-2 and the third optical path reflection point 10-3. A third reflected optical path connecting line is formed between the third optical path reflection point 10-3 and the fourth optical path reflection point 10-4. The angle range between the first and third reflected optical path connecting lines and the angle range between the second and third reflected optical path connecting lines are both 23 degrees to 27 degrees. In this embodiment, the two angles are preferably 25 degrees to ensure the stability of the closed annular optical path.

[0062] In this embodiment, when assembling the temperature control system, a platinum resistance temperature sensor is selected. Its probe end is embedded in the preset mounting hole on the left side of the base plate 4, directly contacting the pure copper material of the base plate 4, and is used to collect the real-time temperature signal of the base plate 4. The semiconductor cooler 2 is connected to the built-in temperature sensor and the PID temperature control module through two electrode wires respectively. The PID temperature control module is fixed on the inner wall of the laser housing, and forms a closed-loop control circuit with the semiconductor cooler 2 and the temperature sensor through wires, with a temperature control accuracy of ±0.01℃. Example 1

[0063] In an environment of 25℃±2℃, the combined base plate structure described in this invention was assembled into the annular cavity of the laser. The laser operated continuously for 24 hours, and the peak-to-peak stability of the 509nm laser power output by the laser was better than 0.8%. During this period, no adjustment of the cavity mirror position was required, proving that the structural stability met the requirements. Example 2

[0064] The combined base plate structure described in this invention is assembled into the annular cavity of the laser. The PID temperature control module is set to a control temperature of 28.0℃. Then, the laser is placed in a temperature control chamber and subjected to a temperature cycle test of 20℃-35℃. During the entire cycle, the laser remains stably locked in the cavity, and the output power fluctuation is ≤±0.2%. After the test, the cavity mirror position is not offset and no recalibration is required. The temperature control system composed of the PID temperature control module and the temperature sensor can effectively resist the interference of ambient temperature. Example 3

[0065] The combined base plate structure described in this invention is assembled into the annular cavity of the laser. When installing the support plate 1, the fixing screws are intentionally tightened unevenly to simulate the assembly stress that may be generated during the actual assembly process. The flatness change of the upper surface of the mounting plate 5 is ≤1μm as measured by an electronic level and a dial indicator. The laser optical path is established normally, and the output power stability is better than 1.0%, proving that the combined base plate structure described in this invention can effectively isolate the lower layer assembly stress from the upper layer optical platform 8.

[0066] This invention also provides a heat dissipation method for a combined base plate structure of a laser, applied to a combined base plate structure of a laser, as shown in the attached figure. Figure 6 As shown, it includes the following steps:

[0067] S01. Heat absorption step: Multiple optical components of the laser are fixedly installed on the optical platform 8. The pure copper base plate 4 quickly absorbs the heat generated when the optical components are working, and then diffuses the heat evenly through its lateral thermal conductivity, and transfers the heat to the semiconductor cooler 2 in the middle layer.

[0068] Preferably, in the heat absorption step, multiple optical components of the laser are respectively fixedly mounted on the optical platform 8, specifically including:

[0069] S101. The pump source, laser crystal, frequency doubling crystal, first reflector, second reflector, third reflector, and fourth reflector of the laser are respectively fixedly installed in the pump source mounting area 9-1, laser crystal mounting area 9-2, frequency doubling crystal mounting area, first reflector mounting area 9-4, second reflector mounting area 9-5, third reflector mounting area 9-6, and fourth reflector mounting area 9-7 on the optical platform 8; the pure copper base plate 4 utilizes its high thermal conductivity to quickly absorb the heat generated by the pump source, laser crystal, and frequency doubling crystal during operation, and evenly diffuses the heat to the entire base plate 4 through the lateral thermal conductivity of pure copper, eliminating local hot spots and reducing thermal deformation caused by thermal gradient.

[0070] S02. Heat Transfer and Active Temperature Control Steps: The top surface of the semiconductor cooler 2 is used as its cold surface. After being tightly attached to the bottom surface of the base plate 4, the cold surface receives heat from the base plate 4. The bottom surface of the semiconductor cooler 2 is used as its hot surface. The hot surface is tightly attached to the top surface of the support plate 1, and the hot surface transfers heat to the support plate 1. At the same time, the real-time temperature signal of the base plate 4 is collected by the temperature sensor and fed back to the PID temperature control system. When the temperature of the base plate 4 is higher than the set value, the PID temperature control system adjusts the operating current of the semiconductor cooler 2 to enhance the cooling power. When the temperature is lower than the set value, the operating current is reduced to maintain temperature stability, and finally the temperature of the base plate 4 is controlled within ±0.01℃ of the set value. In this embodiment, the active closed-loop temperature control of the base plate 4 by the PID temperature control system keeps the temperature of the base plate 4 within the set range.

[0071] S03. Heat export and dissipation steps: The support plate 1 receives the heat released from the hot surface of the semiconductor cooler 2. Utilizing the thermal conductivity of aluminum alloy, the heat is then quickly conducted to the laser housing through the connection structure between the support plate 1 and the laser housing. Finally, the heat is dissipated to the external environment through the natural convection between the housing and the outside atmosphere, completing the entire heat export process.

[0072] S04. Reverse thermal isolation step: The top surface of the thermal insulation pad 3 is attached to the bottom surface of the base plate 4, and the bottom surface of the thermal insulation pad 3 is attached to the top surface of the support plate 1. The thermal insulation pad 3, located between the support plate 1 and the base plate 4, uses its low thermal conductivity to thermally isolate the support plate 1 and the base plate 4, thereby blocking the heat transfer path in the non-contact area between the support plate 1 and the base plate 4, preventing external ambient heat or the heat of the support plate 1 from being conducted back to the base plate 4, and ensuring that the accuracy of active temperature control is not disturbed.

[0073] The heat dissipation method of the combined base plate structure of the laser described in the embodiments of the present invention can not only achieve the temperature stability of the base plate 4 at 28.0℃±0.01℃ and the temperature gradient ≤±0.03℃, but also ensure that the peak-to-peak stability of the 509nm laser output power of the laser is better than 0.8% and the frequency doubling conversion efficiency is improved by ≥5%, thus meeting the long-term stable operation requirements of the laser's ring cavity.

Claims

1. A combined base plate structure for a laser, wherein the combined base plate structure is a multi-layer plate integral structure fixedly connected to the bottom of the laser cavity, characterized in that, Including: The support plate (1) located in the lower layer has its bottom surface fixedly connected to the bottom of the inner cavity of the laser housing and is used to transfer heat to the laser housing; The semiconductor cooler (2) and the heat insulation pad (3) are located in the middle layer. The semiconductor cooler (2) is embedded into the heat insulation pad (3) from one side and forms a first square structure for temperature control with the heat insulation pad (3). The bottom surface of the first square structure is attached to the top surface of the support plate (1) and is used to transfer heat to the support plate. The base plate (4) and mounting plate (5) are located on the upper layer. The mounting plate (5) is embedded in the base opening (4-1) of the base plate (4) to form a second square structure for absorbing heat from the heat source. The first protrusion (6) and the second protrusion (7) at the bottom of the base opening near the middle are respectively embedded in the opening of the mounting plate. The bottom surface of the second square structure is attached to the top surface of the first square structure and is used to conduct heat to the first square structure. Its top surface is an optical platform (8) for supporting multiple optical components and absorbing heat.

2. The combined base plate structure of a laser as described in claim 1, characterized in that: The optical platform (8) includes a base plate top surface (8-1) located on the left side of the top surface of the second square body, a first protruding top surface (8-2) and a second protruding top surface (8-3) located in the middle, and a mounting plate top surface (8-4) located in the middle and right sides; the base plate top surface (8-1), the first protruding top surface (8-2), and the second protruding top surface (8-3) are all set as mounting areas for optical components to be dissipated; The top surface of the base plate (8-1), the top surface of the mounting plate (8-4), the top surface of the first protrusion (8-2), and the top surface of the second protrusion (8-3) are on the same horizontal plane.

3. The combined base plate structure of a laser as described in claim 1, characterized in that: The heat insulation pad (3) has a square opening (3-1) on one side along its length that is adapted to the shape of the semiconductor cooler (2). The semiconductor cooler (2) is embedded in the square opening (3-1) and its two adjacent sides are in contact with the inner side of the square opening (3-1). The base plate (4) has a base opening (4-1) on its right side along the height direction, which is adapted to the shape of the mounting plate (5). The first protrusion (6) is located in the middle rear position of the base opening (4-1), and the second protrusion (7) is located in the middle front position of the base opening (4-1). The bottom surface of the base plate (4) has a square groove (4-2) along its height direction that is adapted to the shape of the semiconductor cooler (2). The semiconductor cooler (2) is vertically embedded in the square groove (4-2), and the top surface of the semiconductor cooler (2) is in contact with the top wall of the square groove (4-2). The mounting plate (5) has openings including a first opening (5-1) and a second opening (5-2), and the first opening (5-1) and the second opening (5-2) are respectively adapted to the shape of the first protrusion (6) and the shape of the second protrusion (7); the mounting plate (5) is inserted into the base opening (4-1) of the base plate (4) from the top surface of the base plate (4) along its height direction.

4. The combined base plate structure of a laser as described in claim 1, characterized in that: The mounting areas of the plurality of optical components include a pump source mounting area (9-1) disposed on the top surface (8-1) of the base plate, a laser crystal mounting area (9-2) disposed on the top surface (8-2) of the first protrusion, and a frequency doubling crystal mounting area (9-3) disposed on the top surface (8-3) of the second protrusion. The laser crystal mounting area (9-2) has a first mirror mounting area (9-4) and a second mirror mounting area (9-5) on its left and right sides, and the frequency doubling crystal mounting area (9-3) has a third mirror mounting area (9-6) and a fourth mirror mounting area (9-7) on its left and right sides. The first mirror mounting area (9-4) is located between the pump source mounting area (9-1) and the laser crystal mounting area (9-2). The third mirror mounting area (9-6) is located directly in front of the first mirror mounting area (9-4). The fourth mirror mounting area (9-7) is located directly in front of the second mirror mounting area (9-5).

5. The combined base plate structure of a laser as described in claim 4, characterized in that: The first reflector mounting area (9-4) is provided with a first optical path reflection point (10-1), the second reflector mounting area (9-5) is provided with a second optical path reflection point (10-2), the third reflector mounting area (9-6) is provided with a third optical path reflection point (10-3), and the fourth reflector mounting area (9-7) is provided with a fourth optical path reflection point (10-4). A first reflected light path connection line is formed between the first light path reflection point (10-1) and the fourth light path reflection point (10-4); a second reflected light path connection line is formed between the second light path reflection point (10-2) and the third light path reflection point (10-3); and a third reflected light path connection line is formed between the third light path reflection point (10-3) and the fourth light path reflection point (10-4). The angle α between the first and third reflected light path connection lines and the angle β between the second and third reflected light path connection lines are both 23 degrees to 27 degrees.

6. A combined base plate structure for a laser as described in any one of claims 1, 2, or 3, characterized in that: The top surface of the semiconductor cooler (2) is covered with thermally conductive silicone grease, and the top surface of the semiconductor cooler (2) is attached to the top wall of the square groove on the bottom surface of the base plate (4) by the thermally conductive silicone grease. The semiconductor cooler (2) is connected to the built-in temperature sensor and the external temperature control module respectively, and the temperature sensor is attached to the base plate (4).

7. The combined base plate structure of a laser as described in claim 1, characterized in that: The support plate (1) is made of aluminum alloy, the heat insulation pad (3) is made of non-metallic material, the base plate (4) is made of pure copper, and the mounting plate (5) is made of Invar steel.

8. The combined base plate structure of a laser as described in claim 7, characterized in that: The thermal conductivity of the pure copper is greater than or equal to 390 W / (m·K), and the coefficient of linear expansion of Invar is less than or equal to 1.5 × 10⁻⁻⁻⁶. 6 / ℃, the tensile strength of the aluminum alloy is greater than or equal to 210MPa.

9. A heat dissipation method for a combined base plate structure of a laser, applied to the combined base plate structure of the laser according to any one of claims 1 to 8, characterized in that, Includes the following steps: Heat absorption step: The multiple optical components of the laser are fixedly installed on the optical platform. The pure copper base plate (4) quickly absorbs the heat generated when the optical components are working, and then diffuses the heat evenly through its lateral heat conduction capability and transfers the heat to the semiconductor cooler (2) in the middle layer. Heat transfer and active temperature control steps: By using the top surface of the semiconductor cooler (2) as its cold surface and tightly attaching it to the bottom surface of the base plate (4), the cold surface receives heat from the base plate (4). By using the bottom surface of the semiconductor cooler (2) as its hot surface and tightly attaching it to the top surface of the support plate (1), the hot surface transfers heat to the support plate (1). At the same time, the real-time temperature signal of the base plate is collected by the temperature sensor and fed back to the PID temperature control system. The PID temperature control system actively controls the temperature of the base plate in a closed loop, so that the temperature of the base plate (4) is controlled within the set range. Heat export and dissipation steps: The support plate (1) receives the heat released from the hot surface of the semiconductor cooler (2), and then conducts the heat to the laser housing through the connection structure between the support plate (1) and the laser housing; Reverse thermal isolation step: By using the thermal insulation pad (3) to thermally isolate the support plate (1) from the base plate (4), the heat of the support plate (1) is blocked from being conducted to the base plate (4) in the reverse direction.

10. The heat dissipation method for a combined base plate structure of a laser as described in claim 9, characterized in that, In the heat absorption step, multiple optical components of the laser are respectively fixedly mounted on an optical platform, including: The pump source, laser crystal, frequency doubling crystal, first reflector, second reflector, third reflector, and fourth reflector of the laser are fixedly installed in the pump source installation area (9-1), laser crystal installation area (9-2), frequency doubling crystal installation area (9-3), first reflector installation area (9-4), second reflector installation area (9-5), third reflector installation area (9-6), and fourth reflector installation area (9-7) of the optical platform, respectively.

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