A semiconductor laser

Abstract

This application discloses a semiconductor laser, comprising: a laser source; a polarizing mirror, including an incident side, a first reflecting light-emitting side, a second reflecting light-emitting side, and a transmitting light-emitting side; a first waveplate disposed on the first reflecting light-emitting side; and a second waveplate disposed on the transmitting light-emitting side. During operation, the laser emitted by the laser source includes first polarized light and second polarized light with polarization directions perpendicular to each other. The laser light enters the polarizing mirror from the incident side. The first polarized light is reflected by the polarizing mirror, passes through the first waveplate, is repolarized, and exits along a first outgoing light path. A portion of the light reflected back from the working surface along the first outgoing light path is repolarized again by the first waveplate and passes through the polarizing mirror to exit from the second reflecting light-emitting side. The second polarized light passes through the polarizing mirror and the second waveplate, is repolarized, and exits along a second outgoing light path. A portion of the light reflected back from the working surface along the second outgoing light path is repolarized again by the second waveplate and enters the polarizing mirror, then is reflected from the second reflecting light-emitting side.

Description

Technical Field

[0001] This application relates to the technical field of laser devices, and more particularly to a semiconductor laser. Background Technology

[0002] While laser welding technology has made significant progress, it still faces numerous technical bottlenecks in practical applications. One major challenge is the irreversible damage to the laser source caused by feedback light generated during the welding process, particularly in welding highly reflective materials such as copper, gold, and aluminum. This problem has long been a core technical hurdle hindering the expansion of laser welding technology into high-precision and high-reliability applications. To address this feedback light damage issue, existing semiconductor lasers generally employ a protective design that adds polarizing mirrors and waveplates to the optical path to avoid reflected light. However, limited by the performance of the laser module itself, its polarization efficiency typically only reaches 90%–95%. This means that 5%–10% of the non-primarily polarized beam cannot enter the effective output optical path and is instead absorbed by the laser housing, resulting in a significant waste of light source power and a substantial reduction in the overall photoelectric conversion efficiency of the laser. Summary of the Invention

[0003] The purpose of this invention is to provide a semiconductor laser that can solve the aforementioned problems existing in related technologies.

[0004] To achieve the above objectives, this application adopts the following technical solution:

[0005] A semiconductor laser includes at least one set of laser modules, each set of laser modules comprising:

[0006] A laser source, used to emit laser light;

[0007] A polarizing mirror includes an incident side, a first reflective light-emitting side, a second reflective light-emitting side, and a transmissive light-emitting side;

[0008] The first wave plate is disposed on the first light-reflecting side;

[0009] The second wave plate is disposed on the light-transmitting side;

[0010] During operation, the laser emitted by the laser source includes first polarized light and second polarized light with polarization directions perpendicular to each other. The laser enters the polarizing mirror from the incident side. The first polarized light is reflected by the polarizing mirror, passes through the first waveplate to be depolarized, and exits along the first outgoing light path. A portion of the light reflected back from the working surface along the first outgoing light path is depolarized again by the first waveplate and passes through the polarizing mirror to exit from the second reflecting light side. The second polarized light passes through the polarizing mirror and the second waveplate to be depolarized and exits along the second outgoing light path. A portion of the light reflected back from the working surface along the second outgoing light path is depolarized again by the second waveplate and enters the polarizing mirror and is reflected from the second reflecting light side.

[0011] Optionally, the reflective lens groups of the first and / or second outgoing light paths are deflected by the reflective lens groups, so that the final sections of the first and second outgoing light paths remain parallel.

[0012] Optionally, the system includes two sets of laser modules spaced apart along a first direction, wherein the end segments of the first and second outgoing optical paths of the two sets of laser modules extend along a second direction, wherein the second direction is perpendicular to the first direction.

[0013] Optionally, the first reflective light-emitting sides of the two sets of laser modules are arranged facing each other or away from each other. Each set of laser modules also includes a first reflector, which is disposed in the first outgoing light path, such that the end of the first outgoing light path extends along the second direction.

[0014] Optionally, the first light-emitting sides of the two sets of laser modules are arranged facing each other, and a beam combiner is arranged between the two first light-emitting sides, with the two first reflectors respectively formed on both sides of the beam combiner.

[0015] Optionally, the transmission and emission sides of both sets of laser modules are oriented towards the second direction, so that the emission of the second polarized light is directly directed towards the second direction.

[0016] Optionally, each laser module further includes a set of reflective mirrors disposed in the second outgoing optical path. The set of reflective mirrors includes at least two parallel and facing second reflective mirrors. Through two rotations of the set of reflective mirrors, the end of the second outgoing optical path is made closer to the end of the first outgoing optical path.

[0017] Optionally, a focusing lens is also included, the focusing range of which covers the ends of the first and second outgoing optical paths of the two sets of laser modules, so that the outgoing light from both sets of laser modules can be focused by the focusing lens.

[0018] Optionally, each set of laser modules further includes a third reflecting mirror opposite to the laser light source. The laser light sources of the two sets of laser modules are arranged in opposite directions and coaxially. The lasers emitted by the two sets of laser light sources can be projected onto the corresponding third reflecting mirrors in opposite directions parallel to the first direction. After being reflected and redirected by the third reflecting mirrors, they are projected onto the corresponding polarizing mirrors in the first direction.

[0019] Optionally, a stepped heat sink is included, which includes multiple stepped mounting surfaces of different levels. Each stepped mounting surface is provided with two opposing laser light sources. The third reflecting mirror is installed at both ends of each stepped mounting surface, so that each group of laser modules can be provided with multiple laser light sources at the same time, and the laser light sources of two groups of laser modules are jointly mounted on the stepped heat sink.

[0020] The beneficial effects of this application are as follows: Through an innovative polarization control structure, it achieves full utilization of dual-polarized beams and directional interception of feedback light, combining the advantages of improved efficiency and light source protection. On the one hand, it breaks the limitation of non-primary polarized light being absorbed by the shell in traditional solutions, incorporating both the first and second polarized lights with perpendicular polarization directions into the effective output optical path, significantly improving the overall light output efficiency of the laser, while reducing the additional temperature rise caused by stray light absorption, ensuring the operational stability of the equipment. On the other hand, this structure, through the synergistic effect of waveplates and polarizing mirrors, constructs a closed-loop feedback light interception system, which can uniformly guide the bidirectional feedback light generated by welding high-reflectivity materials to the light absorption region, completely avoiding irreversible damage to the laser source by feedback light, significantly expanding the application boundaries of semiconductor lasers in high-reflectivity material welding scenarios, and improving the reliability and applicability of the equipment. Attached Figure Description

[0021] The present application will now be described in further detail with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a schematic diagram of the semiconductor laser described in an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the path of the first polarized light emitted along the first outgoing optical path in an embodiment of this application;

[0024] Figure 3 This is a schematic diagram of the path of the first polarized light returning in reverse along the first outgoing optical path in an embodiment of this application;

[0025] Figure 4 This is a schematic diagram of the path of the second polarized light emitted along the second outgoing optical path in an embodiment of this application;

[0026] Figure 5 This is a schematic diagram of the path of the second polarized light returning in reverse along the second outgoing light path in an embodiment of this application.

[0027] In the picture:

[0028] 1. Laser module; 11. Laser source; 12. Polarizing mirror; 121. Incident side; 122. First reflection exiting side; 123. Transmission exiting side; 124. Second reflection exiting side; 13. First waveplate; 14. Second waveplate; 15. First reflecting mirror; 16. Second reflecting mirror; 17. Third reflecting mirror; 18. Fast axis collimating mirror; 19. Slow axis collimating mirror; 2. Focusing lens; 3. Stepped heat sink; 4. Working surface. Detailed Implementation

[0029] To make the technical problems solved by this application, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of this application are further described in detail below. 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 are within the scope of protection of this application.

[0030] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0032] While laser welding technology has made significant progress, it still faces numerous technical bottlenecks in practical applications. One major challenge is the irreversible damage to the laser source caused by feedback light generated during the welding process, particularly in welding highly reflective materials such as copper, gold, and aluminum. This problem has long been a core technical hurdle hindering the expansion of laser welding technology into high-precision and high-reliability applications. To address this feedback light damage issue, existing semiconductor lasers generally employ a protective design that adds polarizing mirrors and waveplates to the optical path to avoid reflected light. However, limited by the performance of the laser module itself, its polarization efficiency typically only reaches 90%–95%. This means that 5%–10% of the non-primarily polarized beam cannot enter the effective output optical path and is instead absorbed by the laser housing, resulting in a significant waste of light source power and a substantial reduction in the overall photoelectric conversion efficiency of the laser.

[0033] To overcome the above technical problems, embodiments of this application provide a semiconductor laser, including at least one set of laser modules 1, each set of laser modules 1 including:

[0034] Laser source 11, used to emit laser light;

[0035] The polarizing mirror 12 includes an incident side 121, a first reflective light-emitting side 122, a second reflective light-emitting side 124, and a transmission light-emitting side 123.

[0036] The first wave plate 13 is disposed on the first light-reflecting side 122;

[0037] The second wave plate 14 is disposed on the light-transmitting side 123;

[0038] During operation, the laser emitted by the laser source 11 includes first polarized light and second polarized light with polarization directions perpendicular to each other. The laser is incident on the polarizing mirror 12 from the incident side 121. The first polarized light is reflected by the polarizing mirror 12, passes through the first waveplate 13 to be polarized, and is emitted along the first outgoing light path. A portion of the light reflected back from the working surface 4 along the first outgoing light path is repolarized by the first waveplate 13 and passes through the polarizing mirror 12 to be emitted from the second reflecting light side 124. The second polarized light is polarized by the polarizing mirror 12 and the second waveplate 14 and is emitted along the second outgoing light path. A portion of the light reflected back from the working surface 4 along the second outgoing light path is repolarized by the second waveplate 14 and enters the polarizing mirror 12 and is reflected from the second reflecting light side 124.

[0039] In the semiconductor laser structure of this embodiment, the laser source 11 serves as the core light-emitting component of the laser. Its core function is to emit laser light, and the emitted laser light contains two polarization characteristics: first polarized light and second polarized light. The polarization directions of the two are perpendicular to each other, providing a basic light source for subsequent polarization control and optical path allocation. The laser source 11 can be a semiconductor laser source 11.

[0040] The polarizer 12 is the core optical path control element of the entire module. It has four functional end faces: incident side 121, first reflection light-emitting side 122, second reflection light-emitting side 124, and transmission light-emitting side 123. Different end faces undertake different optical path transmission and steering functions: the incident side 121 serves as the input end of the laser, receiving the mixed polarization laser emitted by the laser source 11; the first polarized light in the incident laser is reflected by the polarizer 12 and exported from the first reflection light-emitting side 122, which is the initial output channel of the main polarized light; the second polarized light in the incident laser is directly transmitted through the polarizer 12 and exported from the transmission light-emitting side 123, which is the initial output channel of the auxiliary polarized light; the second reflection light-emitting side 124 is the unified output end of the feedback light, used to concentrate and export the back-following feedback light to the light absorption region, avoiding the feedback light from returning to the light source.

[0041] The first waveplate 13 is disposed on the first reflecting light-emitting side 122 of the polarizer 12. Its core function is to redirect the polarization state of the passing light beam. By changing the polarization direction of the light, it can control the polarization state of the first polarized light and its feedback light, and is a key component for feedback light separation. The second waveplate 14 is fixed on the transmitting light-emitting side 123 of the polarizer 12. It has a similar function to the first waveplate 13, both undertaking the responsibility of polarization state redirection. However, its control object is the second polarized light and its feedback light. Through polarization state conversion, it achieves effective output of the auxiliary polarized light and interception of the feedback light. Both the first waveplate 13 and the second waveplate 14 are quarter-wave plates. When polarized light passes through the quarter-wave plate once, its polarization is redirected by 45°, and when it passes through the quarter-wave plate twice, its polarization is redirected by 90°.

[0042] The first and second output optical paths are functional optical paths of the laser, not physical components. The first output optical path receives the first polarized light after it has been deflected by the first waveplate 13 and guides it to the working surface 4; the second output optical path receives the second polarized light after it has been deflected by the second waveplate 14 and also extends to the working surface 4. Together, they constitute the effective output optical path of the laser.

[0043] The working principle of the semiconductor laser in this embodiment can be divided into two main stages: normal light output and feedback light interception. The core is to achieve full utilization of polarized light and directional output of feedback light by utilizing the polarization selection characteristics of the polarizer 12 and the polarization steering characteristics of the waveplate.

[0044] (a) Normal light emission stage

[0045] 1. Propagation and polarization reversal of first-polarized light

[0046] After the mixed-polarized laser emitted by the laser source 11 enters from the incident side 121 of the polarizer 12, the first polarized light cannot be transmitted due to the polarization selection characteristics of the polarizer 12, but is reflected to the first reflection output side 122. When the beam passes through the first waveplate 13 of the first reflection output side 122, the polarization direction is directionally reversed, and then it is emitted along the first output light path, finally acting on the working surface 4 to complete the effective output of the main polarized light.

[0047] 2. Transmission and polarization reversal of second-polarized light

[0048] Meanwhile, the second polarized light in the hybrid laser, because its polarization direction matches the transmission axis of the polarizer 12, can be directly extracted from the transmission output side 123 through the polarizer 12. When this beam passes through the second waveplate 14 of the transmission output side 123, its polarization direction is oriented and reversed, and then it is emitted along the second output light path and acts on the working surface 4, realizing the effective utilization of the auxiliary polarized light and avoiding the waste of non-primary polarized light in the traditional scheme.

[0049] (II) Feedback Light Interception Stage

[0050] When the laser welds highly reflective materials such as copper, gold, and aluminum, the working surface 4 generates retroreflected feedback light. At this time, the components work together to achieve directional interception of the feedback light.

[0051] 1. Interception of the first polarized light feedback beam

[0052] Part of the feedback light reflected back along the first outgoing light path will pass through the first waveplate 13 in reverse. Since the beam has already passed through the first waveplate 13 once during the normal light output stage, this is a second passage. Its polarization direction will be directionally deflected again on top of the original orientation, and the final polarization state will match the transmission conditions of the polarizing mirror 12. Therefore, the feedback light is no longer reflected after entering the polarizing mirror 12, but passes directly through the polarizing mirror 12 and exits from the second reflection side 124, entering the preset light absorption region.

[0053] 2. Interception of the second polarized light feedback beam

[0054] Part of the feedback light reflected back along the second outgoing light path will pass through the second waveplate 14 in reverse. Due to the second reversal of polarization caused by passing through the waveplate twice, its polarization state will change to a state that can be reflected by the polarizing mirror 12. After entering the polarizing mirror 12, this feedback light will be reflected to the second reflecting light side 124 and emitted, merging with the feedback light of the first polarized light before entering the light absorption region, thus achieving full coverage interception of the feedback light of both polarization states.

[0055] The semiconductor laser provided in this embodiment achieves at least the following beneficial effects: through an innovative polarization control structure, it realizes the full utilization of dual-polarized beams and the directional interception of feedback light, combining the advantages of improved efficiency and light source protection. On the one hand, it breaks the limitation of non-primary polarized light being absorbed by the shell in traditional solutions, incorporating both the first and second polarized lights with perpendicular polarization directions into the effective output optical path, significantly improving the overall light output efficiency of the laser, while reducing the additional temperature rise caused by stray light absorption, ensuring the operational stability of the equipment. On the other hand, through the synergistic effect of the waveplate and polarizing mirror 12, this structure constructs a closed-loop feedback light interception system, which can uniformly guide the bidirectional feedback light generated by welding high-reflectivity materials to the light absorption region, completely avoiding irreversible damage to the laser source 11 by the feedback light, significantly expanding the application boundaries of semiconductor lasers in high-reflectivity material welding scenarios, and improving the reliability and applicability of the equipment.

[0056] In one embodiment, the reflective lens group of the first and / or second outgoing optical paths is deflected by the reflective lens group, so that the end segments of the first and second outgoing optical paths remain parallel.

[0057] Specifically, the first polarized light is output along the first outgoing optical path, and the second polarized light is output along the second outgoing optical path. The initial optical paths of these two beams have angular differences due to the reflection and transmission characteristics of the polarizing mirror 12. If the final segments of the two beams are not parallel, it will lead to spot shift and uneven energy distribution during focusing, affecting welding accuracy and reducing the effective utilization of the beam. Furthermore, non-parallel optical paths increase the design complexity of the focusing mirror 2 and are prone to generating additional energy loss and stray light due to the angle between the optical paths. Therefore, adding a reflective mirror group and ensuring that the final segments of the two outgoing optical paths are parallel is a necessary optimization to guarantee the stability, accuracy, and energy concentration of laser welding.

[0058] The reflective lens group can be configured only in the first output optical path, only in the second output optical path, or in both optical paths, depending on the actual optical path requirements. Its core consists of 1 to 2 high-reflectivity reflective mirrors. The surface of the mirrors is coated with an anti-reflection film for the laser output wavelength to ensure that the energy loss during beam reflection is less than 1%.

[0059] Specifically, generally speaking, the first reflecting light-emitting side 122 of the polarizer 12 is perpendicular to the projected light-emitting side, so the initial emission angle difference between the first polarized light and the second polarized light is 90°. Therefore, if configured only in a single path, the simplest approach is to set a reflector at a 45° angle in the first emission path to achieve directional shift of the light path through reflection; or a reflector at a 45° angle in the second emission path can be set to achieve directional shift of the light path through reflection, ultimately achieving parallel emission of the first and second polarized light at their final stages. If configured in a dual-path configuration, reflectors with appropriate angles are set in the first and second emission paths respectively, adjusting the propagation direction of the two beams to make the first and second polarized light parallel at their final stages.

[0060] This embodiment achieves parallelism at the ends of the dual outgoing optical paths through a reflective lens group. This ensures the overlap and energy uniformity of the two polarized beams during focusing, improving the precision and penetration consistency of laser welding. It also reduces the design and adjustment difficulty of the focusing mirror 2, minimizing energy loss and stray light caused by the optical path angle. In welding applications, a focusing mirror 2 is typically installed at the end of the outgoing optical path to concentrate energy. This solution allows the two beams to enter the focusing mirror 2 at the same incident angle, achieving concentrated energy and reducing the difficulty of setting up the focusing mirror 2. It also avoids additional energy loss and stray light caused by the optical path angle.

[0061] In one embodiment, the semiconductor laser includes two sets of laser modules 1 spaced apart along a first direction. The end segments of the first and second outgoing optical paths of the two sets of laser modules 1 extend along a second direction, wherein the second direction is perpendicular to the first direction.

[0062] In single-module laser solutions, the output power is limited by the power density of the laser unit and the optical path layout, making it difficult to meet the needs of high-power welding scenarios. Furthermore, the energy concentration and spot coverage of a single-module optical path are limited, making it unsuitable for large-size or high-precision welding conditions. However, by arranging two laser modules 1 spaced apart along a first direction and extending the final segments of all outgoing optical paths along a second direction perpendicular to the first direction, the overall output power can be increased through the superposition of the two modules, while ensuring the regularity and consistency of the optical path. This avoids energy loss and spot distortion caused by the intersection of multiple module optical paths, thus meeting the core requirements of medium-to-high power laser welding.

[0063] Specifically, the two sets of laser modules 1 are distributed at intervals along a first direction (such as horizontal). The spacing between the modules can be adjusted according to the actual power requirements and housing size. In application, both sets of modules can be fixed in different step areas of the same heat sink 3 to ensure uniform heat dissipation. The core components of each set of laser modules 1 (laser source 11, polarizer 12, first / second waveplate 14, and reflector group) are independently configured, and the component specifications and installation angles of the two sets of modules are completely identical to ensure the synchronization of optical path output.

[0064] Each module is equipped with an independent set of reflective lenses, which turn their respective first and second outgoing light paths. The angles of the reflective lens sets are precisely calibrated so that the end segments of the first and second outgoing light paths of both modules extend parallel to the second direction (such as vertical longitudinal direction), and the spacing between all outgoing light paths is consistent, ultimately converging on the incident surface of the same focusing lens 2.

[0065] During operation, after the two sets of laser modules 1 are started synchronously, their respective laser sources 11 emit mixed lasers containing first and second polarized light. After polarization separation by polarizing mirror 12 and polarization reversal by first / second waveplate 14, independent first and second outgoing light paths are formed. Subsequently, the reflective lens group of each module directionally reverses the two light paths, so that the end of all outgoing light paths of the two modules extends along the second direction, and the light paths remain parallel and equally spaced, laying the foundation for subsequent focusing.

[0066] Four outgoing light paths (two for each of the two modules) extending along the second direction are simultaneously incident on the focusing lens 2. The focusing lens 2 converges the four beams into a high-energy-density composite light spot. During the welding process, if feedback light is generated, the polarizers 12 and waveplates of the two modules will respectively convert the polarization state of their respective feedback light and guide it to the feedback light collection area to avoid the feedback light from damaging the laser source 11 of either module, thus achieving synchronous protection of the two modules.

[0067] In this embodiment, the power superposition of the two laser modules 1 significantly improves the overall output power of the laser, which can meet the working conditions of medium and high power laser welding. At the same time, the regular vertical optical path layout ensures the parallelism and spot overlap of the multiple beams, improving the welding accuracy and penetration consistency. In addition, the independent feedback light protection structure of the two modules ensures the stability and reliability of the equipment in high reflective material welding scenarios, further expanding the application boundaries of the laser.

[0068] In one embodiment, the first reflective light-emitting sides 122 of the two sets of laser modules 1 are arranged facing each other or back to back. Each set of laser modules 1 further includes a first reflector 15, which is disposed in the first outgoing light path, such that the end of the first outgoing light path extends along the second direction.

[0069] The first reflective light-emitting sides 122 of the two laser modules 1 are arranged facing each other or back to back, which can achieve a compact layout of the modules within a limited housing space and avoid the problem of excessive equipment size caused by unidirectional arrangement. At the same time, this arrangement allows the initial optical paths of the two modules to form a symmetrical or opposite basic shape, which is convenient for subsequent unified guidance to the second direction. The first reflector 15 is added to the first output optical path because the direction of the first polarized light path initially emitted by the module cannot directly match the extension requirements of the second direction. The directional turning function of the reflector is required to accurately adjust the end of the first output optical path to the second direction, ensuring the regularity and consistency of the optical paths of multiple modules and meeting the beam focusing requirements of high-power welding.

[0070] Specifically, when set up facing each other, the first reflective light-emitting sides 122 of the two sets of laser modules 1 are directly opposite each other, and the modules are distributed in opposite directions. The core components such as the laser light source 11 and polarizing mirror 12 of the two sets of modules are installed in a mirror symmetrical manner to ensure the symmetry of the optical path.

[0071] When set up in opposite directions, the first reflective light-emitting sides 122 of the two sets of laser modules 1 are opposite to each other, and the modules are distributed in opposite directions along the first direction.

[0072] Optionally, the first reflector 15 of each laser module 1 is located in the middle section of the first output optical path. The lens is made of a high reflectivity dielectric film (reflectivity ≥99.5% for the working wavelength of the laser). The installation angle can be finely adjusted within the range of 30°~60°. Its bracket and housing are connected by elastic shock absorption to avoid optical path deviation caused by equipment vibration. The installation position of the first reflector 15 is adapted to the arrangement of the first reflective output side 122 of the module to ensure that the end of the optical path extends accurately along the second direction after turning.

[0073] After the two sets of laser modules 1 are started, their respective laser sources 11 emit mixed lasers containing first and second polarized light. After being separated by polarizing mirrors 12, the first polarized light is emitted from the first reflection light-emitting side 122 to form the initial segment of the first outgoing light path, and the second polarized light is emitted from the transmission light-emitting side 123 to form the initial segment of the second outgoing light path. Since the first reflection light-emitting sides 122 of the two sets of modules are set facing each other or back to back, the initial segments of their first outgoing light paths are at an angle to each other or back to back, and cannot extend directly along the second direction.

[0074] If they are arranged in opposite directions: the initial optical path of the first polarized light of module A is emitted towards module B. After being reflected by the first reflector 15, the optical path is deflected in the second direction. The first polarized light of module B is synchronously turned by its first reflector 15. Finally, the last part of the first outgoing optical path of both modules extends parallel to the second direction.

[0075] If they are arranged in opposite directions: the initial optical path of the first polarized light of module A is emitted in a direction away from module B, and the first reflector 15 folds its optical path to the second direction. After the first polarized light of module B is turned by the reflector of the same angle, the second direction extension of the end of the two optical paths is realized.

[0076] In this embodiment, the compact design of the device is achieved by arranging modules facing each other or back to back, effectively reducing the overall size of the laser. At the same time, the first reflector 15 accurately guides the end of the first outgoing light path in the second direction, ensuring the parallelism and focusing accuracy of the dual-module beams. This not only improves the power output capability of the laser but also maintains the integrity of the feedback light protection. Furthermore, it can adapt to different installation space requirements, further enhancing the practicality and compatibility of the product.

[0077] In one embodiment, the first light-emitting sides 122 of the two sets of laser modules 1 are arranged facing each other, and a beam combiner is arranged between the two first light-emitting sides 122. The two first reflectors 15 are respectively formed on both sides of the beam combiner.

[0078] The two sets of laser modules 1 are arranged facing each other on their first reflective light-emitting sides 122, which can maximize the arrangement spacing of the modules in the first direction and realize the miniaturization design of the laser. A beam combiner is set between the two first reflective light-emitting sides 122, and the two first reflectors 15 are placed on both sides of it. On the one hand, the first polarized light of the two sets of modules can be pre-combined directly, reducing the complexity of subsequent optical path integration. On the other hand, the beam-splitting / reflection characteristics of the beam combiner can be used to uniformly control the propagation direction of the two first polarized light paths, ensuring that their end segments extend precisely along the second direction, while ensuring the energy superposition effect of the dual-module beams, meeting the core requirements of high-power welding.

[0079] The beam combiner is tilted and positioned in the middle of the two first light-reflecting sides 122, forming a 45° angle with the optical axes of the two modules' first light-reflecting sides 122. The size of the beam combiner covers the light spot range of the first polarized light of the two modules, avoiding beam overflow and energy loss.

[0080] In one embodiment, the orientation of the light-emitting side 123 of both sets of laser modules 1 is directed towards the second direction, so that the emitted light of the second polarized light is directly directed towards the second direction.

[0081] In this scheme, the orientation of the light-transmitting sides 123 of both laser modules 1 is directly pointed to the second direction, which can eliminate the need for an additional steering component for the second polarized light and simplify the optical path structure; at the same time, it can allow the second polarized light to be emitted directly along the target direction, maintaining optical path coordination with the first polarized light after steering, ensuring the convergence consistency of the dual polarized light and the dual module beam, and further improving the integration and energy utilization of the laser.

[0082] In one embodiment, each laser module 1 further includes a reflective lens group disposed in the second outgoing optical path. The reflective lens group includes at least two parallel and facing second reflective mirrors 16. Through two rotations of the reflective lens group, the end of the second outgoing optical path is made closer to the end of the first outgoing optical path.

[0083] In the initial design, although the second outgoing optical path could extend along the second direction, there was a certain distance between it and the end of the first outgoing optical path. This resulted in insufficient overlap of the beam spots when the two beams were focused, affecting the concentration of welding energy. Furthermore, if the optical path distance was too large, it would increase the difficulty of selecting the focusing mirror 2 and the overall size of the equipment. By setting at least two parallel and opposing second reflecting mirrors 16 to form a reflecting mirror group in the second outgoing optical path, the distance between the end of the second outgoing optical path and the end of the first outgoing optical path can be reduced through two directional adjustments without changing the direction of the optical path extension. This improves the overlap of the double-polarized light spots, thereby optimizing the welding energy density and process effect.

[0084] Specifically, each laser module 1 has at least two second reflectors 16 in its reflector group, which are installed in a parallel and facing orientation with a mirror angle of 180° (i.e., completely parallel), and the mirror spacing can be adjusted according to the optical path offset requirements.

[0085] Optionally, the second reflector 16 is positioned in the middle of the second outgoing optical path. The first second reflector 16 forms a 45° angle with the initial section of the second outgoing optical path, and the second second reflector 16 is parallel to and faces the first second reflector 16, forming another 45° angle with the optical path after the first reflection. The mounting bracket of the reflector has a micron-level fine-tuning function, which can precisely control the offset distance of the second outgoing optical path by adjusting the mirror spacing and angle, ensuring that the distance between its end section and the end section of the first outgoing optical path is reduced to a preset range (usually ≤2mm). At the same time, the bracket and the laser housing are connected with shockproof features to prevent the optical path from shifting due to equipment vibration.

[0086] During operation, the second polarized light is emitted from the transmission light side 123 and undergoes polarization reversal via the second waveplate 14 before entering the initial segment of the second outgoing light path. At this point, the beam extends along the second direction but is spaced from the first outgoing light path. When the beam strikes the first second reflecting mirror 16, it undergoes a 90° reversal due to the 45° angle between the mirror and the light path, shifting laterally towards the first outgoing light path. The shift distance is determined by the mirror spacing.

[0087] After the initial deflection, the beam is directed toward the second mirror 16, which is parallel to the first mirror. Since the second mirror is parallel to the first mirror, the beam will deflect again by 90°, and the deflection direction is symmetrical to the initial deflection. Finally, the beam will continue to extend along the original second direction, and its end position will be significantly closer to the end of the first outgoing beam path after two offsets.

[0088] After being adjusted by the reflective lens group, the distance between the second outgoing light path and the end of the first outgoing light path, which is turned by the first reflective mirror 15, is significantly reduced. The light spots of the two beams when they enter the focusing mirror 2 can be highly overlapped, forming a composite light spot with uniform energy density. When the feedback light is transmitted back along the second outgoing light path, it will also return to the polarizer 12 after two reflections. Its polarization state conversion and output path are not affected by the reflective lens group, ensuring the integrity of the feedback light protection function.

[0089] This embodiment achieves precise alignment of the end of the second outgoing optical path with the end of the first outgoing optical path by setting two parallel, opposing second reflectors 16 in the second outgoing optical path. This significantly improves the spot overlap and energy concentration of the dual-polarized light, optimizing the consistency of laser welding penetration and process stability. Simultaneously, the two-stage turning design adjusts the spacing without changing the direction of the optical path extension, avoiding directional deviations caused by optical path offset. Furthermore, the low-loss, high-reflectivity lens ensures energy utilization, further enhancing the laser's adaptability to high-precision, high-power welding scenarios. In addition, when the focusing lens 2 is set, bringing the ends of the first and second outgoing optical paths closer together reduces the size of the focusing lens 2.

[0090] In one embodiment, a focusing lens 2 is also included, the focusing range of which covers the ends of the first and second outgoing optical paths of the two sets of laser modules 1, so that the outgoing light of the two sets of laser modules 1 can be focused by the focusing lens 2.

[0091] In the optical path architecture of the dual laser module 1, the two modules generate four outgoing beams (two first outgoing beam paths and two second outgoing beam paths). If the focusing range of the focusing lens 2 cannot completely cover the ends of all optical paths, some beams will not be effectively converged, resulting in energy dispersion and incomplete beam spots, which cannot meet the energy density requirements of high-power welding. By setting the focusing lens 2 to cover the ends of all optical paths, all outgoing beams from the dual modules can be converged into a single high-energy-density composite beam spot, ensuring the penetration depth and accuracy of the welding. At the same time, it simplifies the subsequent integration structure of the optical path and avoids the increase in equipment size and cost caused by focusing multiple beams separately.

[0092] Specifically, focusing lens 2 uses a large-aperture aberration-correcting optical lens. Its effective light-passing aperture needs to cover the spot range at the end of all outgoing light paths of the two modules. Typically, the aperture needs to be 10% to 20% larger than the overall distribution width of the four beams to ensure no energy overflow at the beam edge. The focal length of focusing lens 2 needs to be adapted to the working distance of the laser, and its numerical aperture needs to match the divergence angle of the dual-module beams to ensure that the four beams can form a uniform and concentrated spot on the welding working surface after focusing. The spot diameter can be controlled according to welding requirements.

[0093] Focusing lens 2 is mounted on the light-emitting side of the semiconductor laser housing, at the end of all emitted light paths, with its installation angle perpendicular to the direction of light path extension (second direction). Focusing lens 2 is equipped with an adjustable mounting bracket, supporting fine-tuning of focal length and position, allowing for calibration of the focused spot's position and size according to actual welding conditions. The bracket and housing are sealed together, forming a protective layer with the window plate to prevent dust and other impurities from affecting the optical path accuracy. The window plate at the light-emitting port of the semiconductor laser housing is coaxially mounted with focusing lens 2, and the light-transmitting range of the window plate matches the effective aperture of focusing lens 2, without additionally obstructing the emitted beam.

[0094] Since the focusing range of focusing lens 2 covers the ends of all optical paths, the four beams will simultaneously enter the effective light-passing area of ​​focusing lens 2. Under the refraction of the lens, they will converge towards the same focal point on the welding working surface along the preset optical path. During this process, the energy of the main and auxiliary polarized light of the dual-module is superimposed, forming an energy density much higher than that of the single-module, which meets the requirements of medium and high power welding for penetration depth and welding efficiency.

[0095] When the feedback light generated by welding highly reflective materials travels back along the original optical path, it will first pass through the focusing mirror 2. However, the focusing mirror 2 only changes the direction of beam propagation and does not affect its polarization state. After the feedback light is redirected twice by the waveplate and separated by the polarizing mirror 12, it can still be successfully guided to the light absorption region. The setting of the focusing mirror 2 will not interfere with the operation of the overall feedback light protection system.

[0096] In this embodiment, by configuring a focusing mirror 2 that covers the ends of all optical paths of the dual-module, unified and efficient convergence of the four outgoing beams from the dual-module is achieved, which greatly improves the energy density and uniformity of the welding spot and ensures the consistency of the penetration depth and process stability of high-power laser welding. At the same time, the integrated design of the large-aperture focusing mirror 2 simplifies the convergence structure of the multi-beam, reduces the overall size of the equipment, reduces the difficulty of optical path debugging, and does not affect the feedback light protection function, further enhancing the adaptability and practical value of the laser in complex welding conditions.

[0097] In one embodiment, each set of laser modules 1 further includes a third reflecting mirror 17 opposite to the laser light source 11. The laser light sources 11 of the two sets of laser modules 1 are arranged in opposite directions and coaxially. The lasers emitted by the two sets of laser light sources 11 can be projected onto the corresponding third reflecting mirror 17 in opposite directions parallel to the first direction. After being reflected and redirected by the third reflecting mirror 17, they are projected onto the corresponding polarizing mirror 12 in the first direction.

[0098] If the laser light sources 11 of the two laser modules 1 need to emit light directly towards the polarizer 12, it will easily lead to limited space for the modules inside the housing, and the initial direction of the optical path will be singular, which is not conducive to the miniaturization and structural optimization of the overall device. In this embodiment, the two laser light sources 11 are set in a back-to-back and coaxial configuration, which can achieve a symmetrical and compact arrangement of the modules in the first direction, greatly saving the lateral space of the housing; and the addition of a third reflecting mirror 17 opposite to the laser light source 11 can directionally redirect the laser originally projected in the opposite direction along the first direction, so that it is directed towards the polarizer 12 in the first direction, without changing the final transmission path of the beam, and can adapt to the back-to-back coaxial layout of the light sources, taking into account both space utilization and optical path effectiveness.

[0099] After the laser sources 11 of the two laser modules 1 are started synchronously, they each emit a mixed laser containing first polarized light and second polarized light. Since the light sources are coaxial and their output direction is parallel to the first direction, the two lasers will be projected in opposite directions along the first direction and directed towards the corresponding third reflecting mirrors 17 at both ends of the housing. When the laser beam is incident on the third reflecting mirror 17 at a 45° angle, a 90° directional reflection will occur. The propagation direction of the beam will change from the original reverse projection parallel to the first direction to projection towards the polarizer 12 along the second direction. After the redirected mixed laser enters the polarizer 12, it will complete the separation of the first and second polarized light according to the original logic. The first polarized light will be emitted from the first reflection output side 122, and the second polarized light will be emitted from the transmission output side 123. The subsequent beam combining, focusing, and feedback light protection processes are not affected by the initial redirection of the optical path. When the feedback light is transmitted back in reverse, it will also be reflected by the third reflecting mirror 17 along the original optical path and return to the polarizer 12 at the front end of the laser source 11, completing the polarization state conversion and being led out to the light absorption region to ensure the safety of the light source.

[0100] This embodiment achieves efficient utilization of the internal space of the laser housing by setting the two sets of laser light sources 11 in a coaxial, opposite-facing configuration, significantly reducing the lateral volume of the device and improving the product's integration and portability. At the same time, with the precise steering of the third reflecting mirror 17, the special layout of the light source is adapted without changing the final beam transmission path and polarization control logic. This ensures both the effective output and energy superposition of the dual-module beams and maintains the integrity of the feedback light protection system, further optimizing the structural compactness and operational adaptability of the high-power semiconductor laser.

[0101] In one embodiment, a stepped heat sink 3 is included. The stepped heat sink 3 includes multiple stepped mounting surfaces of different levels. Each stepped mounting surface is provided with two opposing laser light sources 11. The two ends of each stepped mounting surface are respectively equipped with third reflective lenses 17, so that each group of laser modules 1 can be provided with multiple laser light sources 11 at the same time, and the laser light sources 11 of two groups of laser modules 1 are jointly mounted on the stepped heat sink 3.

[0102] The stepped heat sink 3 is preferably made of high thermal conductivity copper material. Its surface has multiple stepped mounting surfaces of different levels. The height difference of each stepped mounting surface is adapted to the light output height of the laser light source 11, ensuring that the optical paths of different levels of light sources do not interfere with each other. A finned water channel is set through the bottom of the heat sink, and the water channel covers the projection area of ​​all stepped mounting surfaces to achieve uniform heat dissipation throughout the area.

[0103] Two opposing laser light sources 11 are symmetrically arranged in the central area of ​​each step mounting surface. The two are coaxially arranged and the light emission direction is parallel to the first direction. The light sources are tightly attached to the step mounting surface with thermal grease. The two light sources on the same step mounting surface belong to different laser modules 1, which can realize the parallel integration of two laser modules 1 and greatly improve the light source density per unit area.

[0104] At each end of the mounting surface of each step, corresponding to the light output paths of two opposing laser light sources 11, a third reflecting mirror 17 is installed. The mirror is at a 45° angle to the light output direction of the light source and is fixed with a shockproof bracket that can be finely adjusted. The surface of the mirror is coated with a high reflectivity film, and its effective light transmission aperture covers the spot range of the laser light source 11. The two third reflecting mirrors 17 on the same mounting surface of the step are arranged symmetrically to redirect the lasers of the two opposing light sources to the direction of the polarizing mirror 12 of the corresponding module. The height of the mirrors on different mounting surfaces of the step is matched with the corresponding level of light source to avoid light path crossing.

[0105] This embodiment achieves high-density arrangement and centralized heat dissipation of multiple back-to-back laser light sources 11 through the multi-level integrated design of the stepped heat sink 3. This not only significantly improves the overall output power of the laser to adapt to ultra-high power welding conditions, but also ensures the stability and lifespan of the multi-light source operation. At the same time, the optical path orientation of the back-to-back light sources is completed by the third reflecting mirror 17, realizing the orderly integration of the optical path in a limited space. This balances space utilization and beam focusing accuracy, without damaging the original feedback light protection system, further enhancing the integration and adaptability of the high-power semiconductor laser.

[0106] In one embodiment, a fast-axis collimating lens 18 and a slow-axis collimating lens 19 are disposed between each of the laser light sources 11 and the third reflecting lens 17.

[0107] The laser beam emitted directly from the laser source 11 exhibits a certain divergence angle in both the fast and slow axes. If it is directly projected onto the third reflecting mirror 17 without collimation, the beam spot will rapidly expand during propagation, reducing energy concentration and causing energy loss due to the beam spot overflowing the third reflecting mirror 17. Simultaneously, the divergent beam, after reflection, suffers from poor optical path consistency, affecting the polarization separation accuracy of the subsequent polarizer 12. By adding a fast-axis collimating mirror 18 and a slow-axis collimating mirror 19 between the laser source 11 and the third reflecting mirror 17, bidirectional collimation of the emitted laser can be performed, converting the divergent light into parallel light, ensuring the stability and energy concentration of the beam propagation, and laying a solid foundation for subsequent optical path control.

[0108] Specifically, during operation, the hybrid polarized laser emitted by the laser source 11 first enters the fast-axis collimating lens 18, and the beam that was originally diverging at a large angle in the fast-axis direction is transformed into a parallel beam under the action of the lens; then the beam enters the slow-axis collimating lens 19, and the divergence angle in the slow-axis direction is further compressed, finally forming a laser beam in which both the fast and slow axes are parallel, the energy concentration of the beam is greatly improved, and the consistency of the propagation direction is significantly enhanced.

[0109] Furthermore, in terms of beam collimation and transmission, although the fast-axis and slow-axis collimating lenses 19 can significantly compress the divergence angle of the laser beam and convert it into approximately parallel light, the collimating lens cannot achieve absolute beam collimation due to the physical characteristics of the optical lenses. When the beam propagation path is too long, a diffusion effect will gradually appear, resulting in energy dispersion and beam distortion, which will affect subsequent optical path control and welding accuracy.

[0110] This solution, by arranging the laser light sources 11 on the same stepped mounting surface in a back-to-back and coaxial configuration, minimizes the distance between two adjacent stepped mounting surfaces, significantly shortening the overall propagation path of the laser beam from the light source through collimation and reflection to the polarizer 12. This design compensates for the technical limitations of the collimating lens from a spatial layout perspective. Even if the collimated beam exhibits a slight divergence tendency, the shortened propagation distance greatly reduces the degree of beam spread, ensuring the energy concentration and optical path consistency of the beam when entering the polarization control stage. It also provides spatial conditions for high-density integration of multiple light sources, avoiding energy loss and accuracy degradation caused by excessively long optical paths.

[0111] In the description herein, it should be understood that the terms "upper," "lower," "left," "right," and other orientations or positional relationships are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used merely for descriptive distinction and have no special meaning.

[0112] In the description of this specification, references to terms such as "an embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0113] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0114] The technical principles of this application have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of this application without inventive effort, and these embodiments will all fall within the scope of protection of this application.

Claims

1. A semiconductor laser, characterized by, The laser module (1) comprises at least one laser module (1), each of the laser module (1) comprises: a laser light source (11) for emitting laser light; a polarizing mirror (12) comprising an incident side (121), a first reflection light exit side (122), a second reflection light exit side (124) and a transmission light exit side (123); a first wave plate (13) arranged on the first reflection light exit side (122); a second wave plate (14) arranged on the transmission light exit side (123); wherein the first wave plate (13) and the second wave plate (14) are both quarter wave plates, and during operation, the laser light source (11) emits laser light comprising first polarized light and second polarized light with perpendicular polarization directions, the laser light is incident on the polarizing mirror (12) from the incident side (121); the first polarized light is reflected by the polarizing mirror (12), then passes through the first wave plate (13) to change the polarization direction and is emitted along a first light exit path, and part of the light reflected by the work surface (4) along the first light exit path is incident on the first wave plate (13) again to change the polarization direction and is emitted from the second reflection light exit side (124) through the polarizing mirror (12); the second polarized light passes through the polarizing mirror (12) and the second wave plate (14) to change the polarization direction and is emitted along a second light exit path, and part of the light reflected by the work surface (4) along the second light exit path is incident on the second wave plate (14) again to change the polarization direction, then enters the polarizing mirror (12) from the second reflection light exit side (124).

2. The semiconductor laser of claim 1, wherein, A mirror lens group is arranged on the first light exit path and / or the second light exit path, and the mirror lens group is arranged to change the direction of the light by reflection, so that the end sections of the first light exit path and the second light exit path are parallel.

3. The semiconductor laser of claim 1, wherein, The laser module (1) comprises two groups of laser modules (1) arranged along a first direction, and the end sections of the first light exit path and the second light exit path of the two groups of laser modules (1) extend along a second direction, wherein the second direction is perpendicular to the first direction.

4. The semiconductor laser of claim 3, wherein, The first reflection light exit sides (122) of the two groups of laser modules (1) are arranged facing each other or away from each other, and each group of laser modules (1) further comprises a first mirror (15) arranged in the first light exit path, so that the end section of the first light exit path extends along the second direction.

5. The semiconductor laser of claim 4, wherein, The first reflection light exit sides (122) of the two groups of laser modules (1) are arranged facing each other, and a beam combining mirror is arranged between the two first reflection light exit sides (122), and the two first mirrors (15) are arranged on the two sides of the beam combining mirror.

6. The semiconductor laser of claim 3, wherein, The transmission light exit sides (123) of the two groups of laser modules (1) are both arranged to face the second direction, so that the second polarized light is emitted directly in the second direction.

7. The semiconductor laser of claim 6, wherein, Each of the laser module (1) further comprises a second mirror set arranged in the second exit light path, the second mirror set comprises at least two second mirrors (16) arranged in parallel and opposite directions, and the last section of the second exit light path is closer to the last section of the first exit light path through twice turning of the second mirror set.

8. The semiconductor laser of claim 3, wherein, Further comprising a focusing mirror (2), the focusing range of the focusing mirror (2) covers the last sections of the first exit light path and the second exit light path of the two laser modules (1), so that the exit light of the two laser modules (1) can be collected by the focusing mirror (2).

9. The semiconductor laser of claim 3, wherein, Each of the laser module (1) further comprises a third mirror set (17) opposite to the laser light source (11), the laser light sources (11) of the two laser modules (1) are arranged in opposite and coaxial directions, and the laser emitted by the two laser light sources (11) can be projected in opposite directions along the first direction to the corresponding third mirror set (17), and then projected to the corresponding polarizing mirror (12) along the first direction after reflection and turning of the third mirror set (17).

10. The semiconductor laser of claim 9, wherein, Further comprising a stepped heat sink (3), the stepped heat sink (3) comprises a plurality of stepped mounting surfaces of different levels, each of the stepped mounting surfaces is provided with two opposite laser light sources (11), and the two ends of each of the stepped mounting surfaces are respectively provided with the third mirror set (17), so that a plurality of laser light sources (11) are arranged in each of the laser modules (1), and the laser light sources (11) of the two laser modules (1) are commonly mounted on the stepped heat sink (3).

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