Semiconductor laser

Abstract

The invention discloses a semiconductor laser, which comprises a laser light source; the polarizer comprises an incident side, a first reflection light-emitting side, a second reflection light-emitting side and a transmission light-emitting side; the first wave plate is arranged on the first reflection light emitting side; the second wave plate is arranged on the transmission light-emitting side; during working, laser emitted by the laser light source comprises first polarized light and second polarized light, the polarization directions of the first polarized light and the second polarized light are perpendicular to each other, and the laser enters the polarizer from the incidence side; the first polarized light is reflected by the polarizer, passes through the first wave plate to be subjected to polarization turning and is emitted along a first emergent light path, and part of light reflected back along the first emergent light path on the working surface passes through the first wave plate to be subjected to polarization turning again and passes through the polarizer to be emitted from a second reflection emergent light side; the second polarized light passes through the polarizer and the second wave plate to be subjected to polarization turning and is emitted out along a second emergent light path, and part of light reflected back along the second emergent light path on the working surface is subjected to polarization turning through the second wave plate again, then enters the polarizer and is reflected out from the second reflection emergent light side.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser equipment, and in particular to a semiconductor laser. BACKGROUND

[0002] Although laser welding technology has achieved great development, it still faces many technical bottlenecks in practical application. Among them, for the welding scene of high reflectivity materials such as copper, gold and aluminum, the feedback light generated during the welding process is easy to cause irreversible damage to the laser light source, which has been a core technical difficulty restricting the expansion of laser welding technology to high-precision and high-reliability fields for a long time. In order to solve the problem of feedback light damage, the existing semiconductor laser generally adopts the protection design of adding a polarizer and a wave plate in the optical path to avoid the reflected light. However, due to the limitation of the performance of the laser module itself, its polarization efficiency can usually only reach 90%~95%, which makes the 5%~10% of the non-main polarization state light beam unable to enter the effective output light path and can only be absorbed by the laser shell, causing a large waste of light source power and significantly reducing the overall photoelectric conversion efficiency of the laser. SUMMARY

[0003] The purpose of the embodiment of the present application is to provide a semiconductor laser which can solve the above-mentioned problems existing in the related art.

[0004] In order to achieve the above-mentioned purpose, the following technical solutions are adopted in the present application: A semiconductor laser, comprising at least one group of laser modules, each group of laser modules comprising: a laser light source for emitting laser light; a polarizer comprising an incident side, a first reflected light emitting side, a second reflected light emitting side and a transmitted light emitting side; a first wave plate arranged at the first reflected light emitting side; a second wave plate arranged at the transmitted light emitting side; Wherein, during operation, the laser light emitted by the laser light source includes first polarized light and second polarized light with perpendicular polarization directions, and the laser light is incident on the polarizer from the incident side; the first polarized light is reflected by the polarizer, then passes through the first wave plate to be converted to polarization, and is emitted along a first emission light path; part of the light reflected by the work surface along the first emission light path passes through the first wave plate again to be converted to polarization, and is emitted from the second reflected light emitting side through the polarizer; the second polarized light passes through the polarizer and the second wave plate to be converted to polarization, and is emitted along a second emission light path; part of the light reflected by the work surface along the second emission light path passes through the second wave plate again to be converted to polarization, and is reflected from the second reflected light emitting side through the polarizer.

[0005] Optionally, the mirror lens group is arranged on the first exit light path and / or the second exit light path, and the first exit light path and the last segment of the second exit light path are kept parallel through reflection of the mirror lens group.

[0006] Optionally, two groups of the laser module are arranged along the first direction, and the last segments of the first exit light path and the second exit light path of the two groups of the laser module extend along the second direction, wherein the second direction is perpendicular to the first direction.

[0007] Optionally, the first reflection light exit sides of the two groups of the laser module are arranged facing each other or away from each other, and each group of the laser module further comprises a first mirror arranged in the first exit light path, so that the last segment of the first exit light path extends along the second direction.

[0008] Optionally, the first reflection light exit sides of the two groups of the laser module are arranged facing each other, and a beam combining mirror is arranged between the two first reflection light exit sides, and the two first mirrors are respectively formed on two sides of the beam combining mirror.

[0009] Optionally, the transmission light exit sides of the two groups of the laser module are both directed towards the second direction, so that the second polarized light is directly emitted towards the second direction.

[0010] Optionally, each group of the laser module further comprises a mirror lens group arranged on the second exit light path, and the mirror lens group comprises at least two second mirrors arranged in parallel and facing each other, and the last segment of the second exit light path is closer to the last segment of the first exit light path through twice reflection of the mirror lens group.

[0011] Optionally, a focusing mirror is further included, and a focusing range of the focusing mirror covers the last segments of the first exit light path and the second exit light path of the two groups of the laser module, so that the emitted light of the two groups of the laser module can be collected by the focusing mirror.

[0012] Optionally, each group of the laser module further comprises a third mirror piece opposite to the laser light source, and the laser light sources of the two groups of the laser module are arranged away from and coaxially with each other, and the laser light emitted by the two groups of the laser light sources can be projected in opposite directions along a direction parallel to the first direction to the corresponding third mirror piece, and then reflected and turned through the third mirror piece to be projected towards the corresponding polarizing mirror along the first direction.

[0013] Optionally, the step heat sink comprises a plurality of step mounting surfaces of different levels, each of the step mounting surfaces is provided with two opposite laser light sources, and two ends of each of the step mounting surfaces are respectively provided with the third reflecting mirror.

[0014] The application has the following advantages: through the innovative polarization control structure, full utilization of the dual-polarization light beam and directional interception of the feedback light are realized, and the efficiency is improved and the light source is protected. On the one hand, the first and second polarized light with a perpendicular polarization direction are both included in the effective output light path, which greatly improves the overall light output efficiency of the laser and reduces the additional temperature rise caused by stray light absorption, thereby ensuring the working stability of the equipment. On the other hand, the structure cooperates with the wave plate and the polarizing mirror to form a closed-loop feedback light interception system, which can guide the bidirectional feedback light generated by the welding of the high-reflectivity material to the light absorption area, thereby avoiding the irreversible damage of the feedback light to the laser light source, significantly expanding the application boundary of the semiconductor laser in the welding of high-reflectivity materials, and improving the reliability and application range of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0015] The application will be further described in detail below with reference to the drawings and embodiments.

[0016] Figure 1 The structure of the semiconductor laser described in the embodiments of the application is shown in the schematic diagram. Figure 2 The path of the first polarized light emitted along the first exit light path in the embodiments of the application is shown in the schematic diagram. Figure 3 The path of the first polarized light returned in reverse along the first exit light path in the embodiments of the application is shown in the schematic diagram. Figure 4 The path of the second polarized light emitted along the second exit light path in the embodiments of the application is shown in the schematic diagram. Figure 5 The path of the second polarized light returned in reverse along the second exit light path in the embodiments of the application is shown in the schematic diagram.

[0017] In the drawings: 1, laser module; 11, laser light source; 12, polarizing mirror; 121, incident side; 122, first reflecting light exit side; 123, transmitting light exit side; 124, second reflecting light exit side; 13, first wave plate; 14, second wave plate; 15, first reflecting mirror; 16, second reflecting mirror; 17, third reflecting mirror; 18, fast-axis collimating mirror; 19, slow-axis collimating mirror; 2, focusing mirror; 3, step heat sink; 4, working surface. DETAILED DESCRIPTION

[0018] In order to make the technical problems solved by the present application, the technical solutions adopted and the technical effects achieved more clear, the technical solutions of the embodiments of the present application are further described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0019] In the description of the present application, unless explicitly defined and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0020] In the present application, unless explicitly defined and limited, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0021] Although laser welding technology has made great progress, it still faces many technical bottlenecks in practical application. Among them, for the welding scene of high reflectivity materials such as copper, gold and aluminum, the feedback light generated during the welding process is easy to cause irreversible damage to the laser light source. This problem has long been a core technical difficulty restricting the expansion of laser welding technology to high-precision and high-reliability fields. In order to solve the problem of feedback light damage, the existing semiconductor laser generally adopts the protective design of adding a polarizer and a wave plate in the optical path to avoid reflected light. However, limited by the performance of the laser module itself, its polarization efficiency can usually only reach 90%~95%, which makes the 5%~10% of the non-main polarization state light beam unable to enter the effective output light path, and can only be absorbed by the laser shell, causing a large waste of light source power and significantly reducing the overall photoelectric conversion efficiency of the laser.

[0022] To overcome the above technical problems, the embodiment of the present application provides a semiconductor laser, comprising at least one set of laser modules 1, each set of the laser modules 1 comprising: 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, during operation, the laser light emitted by the laser light source 11 comprises first polarized light and second polarized light with mutually 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 be converted to be polarized 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 again converted to be polarized by the first wave plate 13 and is emitted from the second reflection light exit side 124 through the polarizing mirror 12; the second polarized light is transmitted through the polarizing mirror 12 and the second wave plate 14 to be converted to be polarized 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 again converted to be polarized by the second wave plate 14, then enters the polarizing mirror 12 and is reflected from the second reflection light exit side 124.

[0023] In the structure of the semiconductor laser of the embodiment, the laser light source 11 is the core light-emitting component of the laser, and its core function is to emit laser light, and the emitted laser light contains light beams with two polarization characteristics, i.e., first polarized light and second polarized light, and the polarization directions of the two are perpendicular to each other, which provides a basic light source for subsequent polarization regulation and light path distribution. The laser light source 11 can be a semiconductor laser light source 11.

[0024] The polarizing mirror 12 is the core regulation element of the light path of the whole module, and has four functional end faces, i.e., the incident side 121, the first reflection light exit side 122, the second reflection light exit side 124 and the transmission light exit side 123, and different end faces bear different light path transmission and conversion functions: the incident side 121 is the input end of the laser light, and receives the mixed polarization state laser light emitted by the laser light source 11; the first polarized light in the incident laser light is reflected by the polarizing mirror 12 and is guided out from the first reflection light exit side 122, which is the initial output channel of the main polarized light; the second polarized light in the incident laser light is directly transmitted through the polarizing mirror 12 and is guided out from the transmission light exit side 123, which is the initial output channel of the auxiliary polarized light; the second reflection light exit side 124 is the unified guide-out end of the feedback light, and is used for guiding the feedback light back to the light absorption area, so as to avoid the feedback light back loss of the light source.

[0025] The first wave plate 13 is arranged on the first reflection light exit side 122 of the polarizer 12, and its core function is to change the polarization state of the passing light beam. By changing the polarization direction of the light, the polarization state of the first polarized light and the feedback light can be regulated, and the first wave plate 13 is a key element for separating the feedback light. The second wave plate 14 is fixed on the transmission light exit side 123 of the polarizer 12, and has a function similar to that of the first wave plate 13, both of which are responsible for changing the polarization state. However, the second wave plate 14 regulates the second polarized light and the feedback light, and through polarization state conversion, the auxiliary polarized light is effectively outputted and the feedback light is intercepted. The first wave plate 13 and the second wave plate 14 are both quarter-wave plates. When the polarized light passes through the quarter-wave plate once, the polarization direction is changed by 45°, and when the polarized light passes through the quarter-wave plate twice, the polarization direction is changed by 90°.

[0026] The first light exit path and the second light exit path are functional light paths of the laser, and are not physical components. The first light exit path guides the first polarized light after being changed by the first wave plate 13 to the working surface 4, and the second light exit path guides the second polarized light after being changed by the second wave plate 14 to the working surface 4, both of which form an effective output light path of the laser.

[0027] The working principle of the semiconductor laser of the embodiment can be divided into two stages: normal light output and feedback light interception. The core is to realize full utilization of polarized light and directional output of feedback light through the polarization selection characteristics of the polarizer 12 and the polarization conversion characteristics of the wave plate. (I) Normal light output stage 1. Transmission and polarization conversion of the first polarized light The mixed polarization state laser emitted by the laser light source 11 is incident from the incident side 121 of the polarizer 12. Due to the polarization selection characteristics of the polarizer 12, the first polarized light cannot be transmitted but is reflected to the first reflection light exit side 122. When the light beam passes through the first wave plate 13 on the first reflection light exit side 122, the polarization direction is changed in a directional manner, and then the light beam is emitted along the first light exit path and finally acts on the working surface 4, thereby realizing effective output of the main polarized light.

[0028] 2. Transmission and polarization conversion of the second polarized light At the same time, the second polarized light in the mixed laser can be directly transmitted from the transmission light exit side 123 of the polarizer 12 because the polarization direction matches the transmission axis of the polarizer 12. When the light beam passes through the second wave plate 14 on the transmission light exit side 123, the polarization direction is changed in a directional manner, and then the light beam is emitted along the second light exit path and acts on the working surface 4, thereby realizing effective utilization of the auxiliary polarized light and avoiding waste of non-main polarized light in the traditional scheme.

[0029] (II) Feedback light interception stage When the laser is used to weld high-reflective materials such as copper, gold, and aluminum, the working surface 4 will generate feedback light through reverse reflection. At this time, the components work together to achieve directional interception of the feedback light. 1. Interception of feedback light of first polarized light Part of the feedback light reflected back along the first exit light path will pass through the first wave plate 13 in reverse. Since the light beam has passed through the first wave plate 13 once during normal light emission, it will pass through the first wave plate 13 again, causing the polarization direction to be deflected again based on the original deflection. Finally, the polarization state matches the transmission condition of the polarizing mirror 12. Therefore, after the feedback light enters the polarizing mirror 12, it is no longer reflected, but directly transmits through the polarizing mirror 12 and is emitted from the second reflection exit side 124 into the preset light absorption area.

[0030] 2. Interception of feedback light of second polarized light Part of the feedback light reflected back along the second exit light path will pass through the second wave plate 14 in reverse. Similarly, due to the second pass through the wave plate, the polarization state is deflected twice, and the polarization state is changed to a state that can be reflected by the polarizing mirror 12. After the feedback light enters the polarizing mirror 12, it is reflected to the second reflection exit side 124 and emitted. After converging with the feedback light of the first polarized light, it enters the light absorption area, achieving full coverage and interception of feedback light of two polarization states.

[0031] The semiconductor laser provided by the embodiment at least achieves the beneficial effect: through the innovative polarization control structure, full utilization of the double-polarization-state light beam and directional interception of the feedback light are achieved, with the dual advantages of efficiency improvement and light source protection. On the one hand, it breaks the limitation of the traditional scheme that non-main polarized light is absorbed by the shell, and the first and second polarized light with a perpendicular polarization direction are both included in the effective output light path, greatly improving the overall light emission efficiency of the laser, while reducing the additional temperature rise caused by stray light absorption, ensuring the working stability of the equipment. On the other hand, the structure builds a closed-loop feedback light interception system through the cooperation of the wave plate and the polarizing mirror 12, which can guide the bidirectional feedback light generated by the welding of high-reflective materials to the light absorption area, completely avoiding the irreversible damage of the feedback light to the laser light source 11, significantly expanding the application boundary of the semiconductor laser in the welding of high-reflective materials, and improving the reliability and application range of the equipment.

[0032] In an embodiment, the mirror lens group of the first exit light path and / or the second exit light path is reflected by the mirror lens group, so that the last segments of the first exit light path and the second exit light path remain parallel.

[0033] Specifically, the first polarized light is output along a first exit light path, and the second polarized light is output along a second exit light path. The initial light paths of the two have an angle difference due to the reflection and transmission characteristics of the polarizing mirror 12. If the two light beams are not parallel at the end, it will cause the light spot to shift and the energy distribution to be uneven when focusing, which not only affects the welding precision, but also reduces the effective utilization of the light beam. At the same time, the non-parallel light path increases the design difficulty of the focusing mirror 2, and extra energy loss and stray light are easily generated due to the light path angle. Therefore, the addition of the reflecting lens group and the parallelism of the end of the double exit light path are necessary optimizations to ensure the stability, accuracy and energy concentration of laser welding.

[0034] Among them, the reflecting lens group can be configured in the first exit light path only, in the second exit light path only, or in both light paths according to actual light path requirements. The core is composed of 1-2 pieces of high reflectivity mirror, and the surface of the lens is coated with a reflection-increasing film for the output wavelength of the laser to ensure that the energy loss is less than 1% when the light beam is reflected.

[0035] Specifically, generally, the first reflection light exit side 122 of the polarizing mirror 12 is perpendicular to the projection light exit side, so the initial exit angle difference of the first polarized light and the second polarized light is 90°. Therefore, if only a single path is configured, the simplest, for example, a 45° angle reflecting mirror can be set in the first exit light path to realize directional offset of the light path through reflection; or a 45° angle reflecting mirror can be set in the second exit light path to realize directional offset of the light path through reflection, and finally realize the parallelism of the exit end of the first polarized light and the second polarized light. If configured in double paths, a reflecting mirror with an adaptive angle is set in the first and second exit light paths respectively, and the propagation directions of the two light beams are adjusted respectively, so that the exit end of the first polarized light and the second polarized light is parallel.

[0036] This embodiment scheme realizes the parallelism of the end of the double exit light path through the reflecting lens group, which not only ensures the light spot coincidence degree and energy uniformity of the two polarized lights when focusing, improves the precision and depth consistency of laser welding, but also reduces the design and debugging difficulty of the focusing mirror 2, and reduces the energy loss and stray light caused by the light path angle. In the welding work, a focusing mirror 2 is needed at the end of the exit light path to realize energy concentration. The two light beams of this scheme enter the focusing mirror 2 at the same incident angle to complete the concentration of energy, which reduces the setting difficulty of the focusing mirror 2 and avoids extra energy loss and stray light caused by the light path angle.

[0037] In an embodiment, the semiconductor laser includes two groups of laser modules 1 arranged at intervals along a first direction, and the end of the first exit light path and the second exit light path of the two groups of laser modules 1 extends along a second direction, wherein the second direction is perpendicular to the first direction.

[0038] In the single-module laser scheme, the output power is difficult to meet the demand of high-power welding scenarios due to the limitation of the power density of the laser unit and the layout of the optical path; meanwhile, the energy concentration and the spot coverage range of the single-module optical path are limited, which cannot adapt to large-size or high-precision welding conditions. In the present application, the two groups of laser modules 1 are arranged along the first direction (e.g. horizontal transverse direction) with a spacing, and the last sections of all the outgoing light paths extend along the second direction (e.g. vertical longitudinal direction) perpendicular to the first direction, which can not only improve the overall output power through the superposition of the two groups of modules, but also ensure the regularity and consistency of the optical path, avoiding the energy loss and spot distortion caused by the intersection of multiple-module optical paths, thereby meeting the core requirements of medium and high-power laser welding.

[0039] Specifically, the two groups of laser modules 1 are distributed along the first direction (e.g. horizontal transverse direction) with a spacing, and the module spacing can be adjusted according to the actual power demand and the size of the shell. In application, the two groups of modules can be fixed on different step regions of the same step heat sink 3 to ensure the uniformity of heat dissipation. The core components (laser light source 11, polarizing mirror 12, first / second wave plate 14, mirror lens group) of each group of laser modules 1 are independently configured, and the specifications and installation angles of the components of the two groups of modules are completely consistent to ensure the synchronization of the optical path output.

[0040] Each group of modules is equipped with an independent mirror lens group for turning the respective first and second outgoing light paths. The angles of the mirror lens groups are precisely calibrated so that the last sections of the first and second outgoing light paths of the two groups of modules extend in parallel along the second direction (e.g. vertical longitudinal direction), and the spacings of all the outgoing light paths are consistent, finally converging to the incident surface of the same focusing lens 2.

[0041] In operation, after the two groups of laser modules 1 are started synchronously, the respective laser light sources 11 emit mixed laser beams containing first and second polarized light, which are separated by the polarizing mirror 12 and turned by the first / second wave plate 14 to form independent first and second outgoing light paths. Then, the mirror lens groups of each group of modules directionally turn the two light paths so that the last sections of all the outgoing light paths of the two groups of modules extend along the second direction, and the light paths maintain a parallel and equally spaced state, laying a foundation for subsequent convergence.

[0042] The four outgoing light paths (two from each group of modules) extending along the second direction are synchronously incident to the focusing lens 2, which converges the four light beams into a high-energy-density composite spot. During the welding process, if feedback light is generated, the polarizing mirrors 12 and wave plates of the two groups of modules will respectively convert the polarization state of the feedback light of each group to guide it to the feedback light collection area, avoiding damage to the laser light sources 11 of any module, and realizing synchronous protection of the two groups of modules.

[0043] In this embodiment, the overall output power of the laser is significantly improved by power superposition of the two groups of laser modules 1, which can meet the working condition requirements of medium and high power laser welding. Meanwhile, the regular vertical light path layout ensures the parallelism and spot coincidence of the multiple light beams, improving the welding precision and penetration consistency. In addition, the independent feedback light protection structure of the double modules ensures the stability and reliability of the equipment in the welding scene of high reflective materials, further expanding the application boundary of the laser.

[0044] In an embodiment, 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. Each group of laser modules 1 further includes a first mirror 15 arranged in the first exit light path, so that the last segment of the first exit light path extends along the second direction.

[0045] 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, which can realize compact layout of the modules in a limited housing space, avoiding the problem of excessive equipment size caused by single-direction arrangement. At the same time, this arrangement can make the initial light paths of the two groups of modules form a symmetrical or reversed basic form, which is convenient for subsequent unified guidance to the second direction. The first mirror 15 is added in the first exit light path because the direction of the first polarized light path initially exited by the module cannot directly match the extension requirement of the second direction. The directional turning function of the mirror is needed to accurately adjust the last segment of the first exit light path to the second direction, ensuring the regularity and consistency of the multi-module light path and meeting the beam convergence requirement of high-power welding.

[0046] Specifically, when arranged facing each other, the first reflection light exit sides 122 of the two groups of laser modules 1 face each other, and the modules are distributed in opposite directions. The laser light sources 11, polarizing mirrors 12 and other core components of the two groups of modules are installed in mirror image symmetry, ensuring the symmetry of the light path.

[0047] When arranged away from each other, the first reflection light exit sides 122 of the two groups of laser modules 1 are away from each other, and the modules are distributed in reverse along the first direction.

[0048] Optionally, the first mirror 15 of each group of laser modules 1 is arranged at the middle segment of the first exit light path. The lens adopts a high reflectivity dielectric film (reflectivity ≥ 99.5% for the working wavelength of the laser), and the installation angle can be adjusted within the range of 30°~60°. The support and the housing are connected by elastic damping to avoid light path deviation caused by equipment vibration. The installation position of the first mirror 15 is adapted to the arrangement mode of the first reflection light exit side 122 of the module, ensuring that the last segment of the light path accurately extends along the second direction after turning.

[0049] After the two groups of laser modules 1 are started, the respective laser light sources 11 emit mixed laser light containing first and second polarized light, which is separated by the polarizing mirror 12, and the first polarized light is emitted from the first reflection light exit side 122 to form an initial segment of the first exit light path, and the second polarized light is emitted from the transmission light exit side 123 to form an initial segment of the second exit light path; since the first reflection light exit sides 122 of the two groups of modules are arranged facing each other or away from each other, the initial segments of the first exit light paths thereof are in a facing or away angle state and cannot be directly extended in the second direction.

[0050] If arranged facing each other: the initial light path of the first polarized light of module A is emitted in the direction of module B, and after being reflected by the first reflecting mirror 15, the light path is deflected in the second direction, and the first polarized light of module B is synchronously deflected by the first reflecting mirror 15 thereof, and finally the terminal segments of the first exit light paths of the two groups of modules are extended in parallel in the second direction; If arranged away from each other: the initial light path of the first polarized light of module A is emitted in a direction away from module B, and the first reflecting mirror 15 folds the light path in the second direction, and after the first polarized light of module B is deflected by the same-angle reflecting mirror, the terminal segments of the two light paths are extended in the second direction.

[0051] In this embodiment, the compact design of the device is realized by arranging the modules facing each other or away from each other, effectively reducing the overall volume of the laser, and at the same time, the first reflecting mirror 15 precisely guides the terminal segment of the first exit light path in the second direction, ensuring the parallelism and convergence accuracy of the light beams of the two modules, improving the power output capability of the laser, maintaining the integrity of the feedback light protection, and adapting to different installation space requirements, further enhancing the practicality and compatibility of the product.

[0052] In one embodiment, 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 reflecting mirrors 15 are formed on the two sides of the beam combining mirror.

[0053] The first reflection light exit sides 122 of the two groups of laser modules 1 are arranged facing each other, which can maximize the compression of the arrangement interval of the modules in the first direction, realizing the miniaturization design of the laser; and the beam combining mirror is arranged between the two first reflection light exit sides 122, and the two first reflecting mirrors 15 are arranged on the two sides thereof, on the one hand, the first polarized light of the two groups of modules can be directly pre-combined, reducing the complexity of subsequent light path integration, and on the other hand, the propagation direction of the two first polarized lights can be uniformly controlled by the beam splitting / reflection characteristics of the beam combining mirror, ensuring the accurate extension of the terminal segments thereof in the second direction, and at the same time, ensuring the energy superposition effect of the light beams of the two modules, meeting the core requirements of high-power welding.

[0054] The beam combiner is obliquely arranged at a middle position between the two first reflection light-out sides 122, and the angle between the optical axis of the beam combiner and the two groups of module first reflection light-out sides 122 is 45°. The size of the beam combiner covers the spot range of the two groups of module first polarized light, so as to avoid energy loss caused by light beam overflow.

[0055] In an embodiment, the transmission light-out sides 123 of the two groups of laser modules 1 are both directed to the second direction, so that the second polarized light is directly emitted to the second direction.

[0056] In this scheme, the transmission light-out sides 123 of the two groups of laser modules 1 are both directly directed to the second direction, so that the second polarized light can be directly emitted to the target direction, and the light path structure is simplified. At the same time, the second polarized light can be directly emitted to the target direction, and the light path of the first polarized light after turning is kept consistent, so as to guarantee the consistency of the convergence of the two polarized lights and the two groups of light beams, and further improve the integration and energy utilization of the laser.

[0057] In an embodiment, each group of laser modules 1 further comprises a reflection lens group arranged in the second light-out path, and the reflection lens group comprises at least two second reflection mirrors 16 arranged in parallel and opposite directions. Through twice turning of the reflection lens group, the end section of the second light-out path is closer to the end section of the first light-out path.

[0058] In the previous scheme, the second light-out path can extend along the second direction, but there is a certain distance between the end section of the second light-out path and the end section of the first light-out path, which will cause insufficient spot coincidence degree of the two light beams when focusing, and affect the concentration of welding energy. At the same time, if the distance between the light paths is too large, the selection of the focusing lens 2 will be difficult, and the overall volume of the equipment will be increased. By arranging at least two second reflection mirrors 16 in parallel and opposite directions to form a reflection lens group, the distance between the end section of the second light-out path and the end section of the first light-out path can be reduced through twice directional turning without changing the extension direction of the light path, so as to improve the spot coincidence degree of the two polarized lights, and further optimize the energy density and process effect of welding.

[0059] Specifically, the reflection lens group of each group of laser modules 1 comprises at least two second reflection mirrors 16 arranged in parallel and opposite directions, and the mirror surface angle is 180° (i.e. completely parallel), and the mirror surface distance can be adjusted according to the light path offset requirement.

[0060] Optionally, the second mirror 16 is arranged at the middle position of the second exit light path, the first second mirror 16 is at a 45° angle with the initial segment of the second exit light path, and the second second mirror 16 is parallel to the first second mirror 16 and is at a 45° angle with the light path after the first reflection; the mounting bracket of the mirror has a micron-level fine adjustment function, the distance of the second exit light path can be accurately controlled by adjusting the distance and angle between the mirror surfaces, and the distance between the end segment of the second exit light path and the end segment of the first exit light path is reduced to a preset range (usually ≤2mm); at the same time, the bracket and the laser shell are connected by shockproof connection to avoid light path deviation caused by equipment vibration.

[0061] When working, the second polarized light is emitted through the transmission light side 123 and enters the initial segment of the second exit light path after the polarization state is turned by the second wave plate 14. At this time, the light beam extends along the second direction but has a distance from the first exit light path. When the light beam is incident on the first second mirror 16, the light beam is turned by 90° due to the 45° angle between the mirror surface and the light path, and is laterally deviated towards the direction close to the first exit light path, and the deviation distance is determined by the distance between the mirror surfaces.

[0062] The light beam after the first turning is incident on the second second mirror 16 which is parallel to the first second mirror 16. Since the second mirror is parallel to the first mirror, the light beam is turned by 90° again, and the turning direction is symmetrical to the first turning. Finally, the light beam continues to extend along the original second direction, and the end segment position has been greatly close to the end segment of the first exit light path after two deviations.

[0063] The second exit light path adjusted by the mirror group has a significantly reduced distance from the end segment of the first exit light path after being turned by the first mirror 15. The light spots of the two light beams when incident on the focusing mirror 2 can be highly overlapped to form a composite light spot with uniform energy density. When the feedback light returns along the second exit light path in the reverse direction, it will also return to the polarizing mirror 12 after being reflected twice. The polarization state conversion and the export path are not affected by the mirror group, which ensures the integrity of the feedback light protection function.

[0064] This embodiment scheme realizes the accurate close of the end segment of the second exit light path to the end segment of the first exit light path by arranging two parallel second mirrors 16 in the second exit light path, greatly improves the light spot overlap degree and energy concentration degree of the double polarized light, and optimizes the penetration consistency and process stability of laser welding. At the same time, the design of two turnings completes the distance adjustment without changing the extension direction of the light path, avoids the directional deviation caused by light path deviation, and the low-loss high-reflectivity mirror ensures the energy utilization rate, further enhances the adaptability of the laser in high-precision and high-power welding scenes. In addition, when the focusing mirror 2 is arranged, the end segments of the first exit light path and the second exit light path are close together, which can realize the size reduction of the focusing mirror 2.

[0065] In an embodiment, a focusing mirror 2 is further included, a focusing range of the focusing mirror 2 covering ends of the first exit light paths and the second exit light paths of the two groups of laser modules 1, so that the exit light of the two groups of laser modules 1 can be collected by the focusing mirror 2.

[0066] In the light path architecture of the double laser module 1, the two groups of modules generate four exit light beams (two groups of first exit light paths and two groups of second exit light paths), if the focusing range of the focusing mirror 2 cannot completely cover the ends of all light paths, it will cause part of the light beams to be unable to be effectively converged, resulting in problems such as energy dispersion and spot defects, which cannot meet the requirements of high-power welding on energy density. The focusing mirror 2 with a focusing range covering all light path ends can converge all exit light of the double module into a high-energy-density composite spot, ensuring the penetration and precision of welding, while simplifying the subsequent integration structure of the light path, avoiding the increase in equipment size and cost caused by focusing multiple light beams.

[0067] Specifically, the focusing mirror 2 adopts a large-aperture aberration-corrected optical lens, the effective light aperture of which needs to cover the spot range of the ends of all exit light paths of the two groups of modules, and the aperture usually needs to be 10%-20% wider than the overall distribution width of the four light beams to ensure that there is no edge beam energy overflow; the focal length of the focusing mirror 2 needs to adapt to the working distance of the laser, and the numerical aperture needs to match the divergence angle of the double module light beam to ensure that the four light beams can form a spot with uniform size and concentrated energy on the welding working surface after focusing, and the spot diameter can be controlled according to the welding requirements.

[0068] The focusing mirror 2 is arranged on the light-emitting side of the shell of the semiconductor laser and located at the ends of all exit light paths, and the installation angle is perpendicular to the light path extension direction (second direction); the focusing mirror 2 is provided with an adjustable mounting bracket supporting fine adjustment of the focal length and position, and the position and size of the focused spot can be calibrated according to the actual welding conditions; the bracket and the shell are connected in a sealed manner, and cooperate with the window sheet to form protection, avoiding the entry of dust and other impurities to affect the light path precision. The window sheet of the light-emitting port of the shell of the semiconductor laser is coaxially installed with the focusing mirror 2, and the light transmission range of the window sheet matches the effective aperture of the focusing mirror 2, without additional shielding of the exit light beam.

[0069] Since the focusing range of the focusing mirror 2 covers the ends of all light paths, the four light beams will enter the effective light transmission area of the focusing mirror 2 at the same time, and under the refraction of the lens, they will converge to the same focal point on the welding working surface along the preset light path. In this process, the main and auxiliary polarized light energy of the double module is superimposed to form an energy density much higher than that of a single module, meeting the requirements of medium and high power welding on penetration and welding efficiency.

[0070] When the feedback light generated by welding high-reflective material is returned along the original light path in the reverse direction, it will first pass through the focusing mirror 2, but the focusing mirror 2 only changes the direction of the light beam transmission and does not affect the polarization state thereof; after the subsequent second turning of the wave plate and the separation of the polarizing mirror 12, the feedback light can still be smoothly guided out to the light absorption area, and the setting of the focusing mirror 2 will not interfere with the operation of the overall feedback light protection system.

[0071] In this embodiment, by configuring the focusing mirror 2 covering the focusing range of all light paths at the ends of the double-mode module, unified and efficient convergence of four light beams emitted by the double-mode module is achieved, the energy density and uniformity of the welding spot are greatly improved, and the consistency of the penetration depth and the process stability of high-power laser welding are ensured; meanwhile, the integrated design of the large-aperture focusing mirror 2 simplifies the convergence structure of the multi-path light beam, reduces the overall volume of the equipment, reduces the difficulty of light path debugging, and does not affect the feedback light protection function, further enhancing the adaptive ability and practical value of the laser in complex welding conditions.

[0072] In an embodiment, each group of the laser module 1 further comprises a third reflecting mirror 17 opposite to the laser light source 11, and the laser light sources 11 of the two groups of the laser module 1 are arranged opposite and coaxially, and the laser light emitted by the two groups of the laser light sources 11 can be projected in opposite directions parallel to the first direction to the corresponding third reflecting mirror 17, and after being reflected and turned by the third reflecting mirror 17, it is projected to the corresponding polarizing mirror 12 along the first direction.

[0073] If the light emitting directions of the laser light sources 11 of the two groups of laser modules 1 need to be directly towards the polarizing mirror 12, it is easy to cause the arrangement space of the modules in the shell to be limited, and the initial direction of the light path is single, which is not conducive to the miniaturization and structural optimization of the whole device. In this embodiment, the two groups of laser light sources 11 are arranged in the opposite and coaxial form, which can realize the symmetrical and compact arrangement of the modules in the first direction, greatly saving the transverse space of the shell; and the third reflecting mirror 17 opposite to the laser light source 11 is additionally arranged, which can directionally turn the laser light originally projected in the reverse direction of the first direction, so that it is projected to the polarizing mirror 12 along the first direction, which does not change the final transmission path of the light beam, and can adapt to the opposite and coaxial layout of the light source, and takes into account the space utilization rate and the effectiveness of the light path.

[0074] After the laser light sources 11 of the two groups of laser modules 1 are synchronously started, each emits mixed laser light containing first polarized light and second polarized light. Since the light sources are coaxial and opposite to each other and the light-emitting directions are parallel to the first direction, the two groups of laser light will be projected in opposite directions along the first direction and respectively towards the corresponding third reflective mirror 17 at the two ends of the shell. When the laser beam is incident on the third reflective mirror 17 at an angle of 45°, 90° directional reflection occurs, and the propagation direction of the light beam changes from the original reverse projection parallel to the first direction to projection along the second direction towards the polarizing mirror 12. After the diverted mixed laser light enters the polarizing mirror 12, the separation of the first and second polarized light is completed according to the original logic, the first polarized light is emitted from the first reflective light-emitting side 122, and the second polarized light is emitted from the transmissive light-emitting side 123. The subsequent beam combining, focusing and feedback light protection processes are not affected by the initial diversion of the light path; when the feedback light is returned in reverse, it will also be reflected by the third reflective mirror 17 along the original light path and returned to the polarizing mirror 12 in front of the laser light source 11, completing the polarization state conversion and being guided out to the light absorption area, thereby ensuring the safety of the light source.

[0075] The embodiment scheme realizes efficient use of the internal space of the laser shell by arranging the two groups of laser light sources 11 in a coaxial and opposite manner, greatly reduces the lateral volume of the device, and improves the integration and portability of the product. At the same time, with the help of the precise diversion of the third reflective mirror 17, the special layout of the light source is adapted without changing the final transmission path of the light beam and the polarization control logic, which not only ensures the effective output and energy superposition of the double-module light beam, but also maintains the integrity of the feedback light protection system, further optimizing the compactness and working condition adaptation of the high-power semiconductor laser.

[0076] In an embodiment, a stepped heat sink 3 is included, which comprises a plurality of stepped mounting surfaces at different levels, each of which is provided with two opposite laser light sources 11, and each end of each stepped mounting surface is provided with a third reflective mirror 17, so that each group of laser modules 1 is provided with a plurality of laser light sources 11, and the laser light sources 11 of the two groups of laser modules 1 are installed on the stepped heat sink 3.

[0077] The stepped heat sink 3 is preferably made of high-thermal-conductivity copper material, and its surface is provided with a plurality of stepped mounting surfaces at different levels, the height difference of each stepped mounting surface is adapted to the light-emitting height of the laser light source 11, so as to ensure that the light paths of different levels of light sources do not interfere with each other; the heat sink bottom is provided with a water channel with fins, which covers the projection area of all the stepped mounting surfaces, achieving uniform heat dissipation in the whole area.

[0078] Two opposite laser light sources 11 are symmetrically arranged in the central area of each step mounting surface, and the two laser light sources are coaxially arranged and have a light emitting direction parallel to the first direction. The light source is tightly attached to the step mounting surface through heat-conducting silicone grease.

[0079] At the two ends of each step mounting surface, a third mirror 17 is mounted corresponding to the light emitting path of the two opposite laser light sources 11. The mirror and the light emitting direction of the light source form a 45° angle, and the mirror is fixed by a shockproof support with adjustable angle. The surface of the mirror is coated with a high-reflectivity film, and the effective light aperture of the mirror covers the spot range of the laser light source 11. The two third mirrors 17 on the same step mounting surface are symmetrically arranged, and the laser light of the two opposite light sources is turned to the direction of the polarization mirror 12 of the corresponding module. The mirror height of different step mounting surfaces is matched with the corresponding level light source to avoid light path intersection.

[0080] In this embodiment, the high-density arrangement and centralized heat dissipation of multiple groups of opposite laser light sources 11 are achieved through the multi-level integrated design of the step heat sink 3. The overall output power of the laser is greatly improved to adapt to the super-high power welding working condition, and the stability and service life of the multi-light source operation are guaranteed. At the same time, the light path of the opposite light sources is oriented by the third mirror 17, and the orderly integration of the light path is realized in a limited space, which takes into account the space utilization rate and the light beam convergence accuracy, and does not damage the original feedback light protection system, further strengthening the integration and working condition adaptation ability of the high-power semiconductor laser.

[0081] In one embodiment, a fast-axis collimating lens 18 and a slow-axis collimating lens 19 are arranged between each laser light source 11 and the third mirror 17.

[0082] The light beam directly emitted by the laser light source 11 has a certain divergence angle in the fast-axis and slow-axis directions. If the light beam is not collimated and directly projected onto the third mirror 17, the spot will rapidly expand during propagation, which not only reduces the energy concentration, but also causes energy loss due to the overflow of the third mirror 17. At the same time, the reflected light beam has poor light path consistency, which affects the polarization accuracy of the polarization mirror 12. By adding a fast-axis collimating lens 18 and a slow-axis collimating lens 19 between the laser light source 11 and the third mirror 17, the emitted laser light can be collimated in both directions to convert the divergent light into parallel light, ensuring the stability of the light beam propagation and the energy concentration, and laying a good foundation for subsequent light path regulation.

[0083] Specifically, during operation, the mixed polarization laser emitted by the laser light source 11 first enters the fast-axis collimating lens 18, and the originally large-angle divergent light beam in the fast-axis direction is converted into a parallel light beam under the action of the lens; then the light beam enters the slow-axis collimating lens 19, and the divergence angle in the slow-axis direction is further compressed, and finally a laser beam with parallel fast and slow axes is formed, and the energy concentration of the light beam is greatly improved, and the consistency of the propagation direction is significantly enhanced.

[0084] In addition, in terms of beam collimation and transmission, although the fast-axis and slow-axis collimating lenses 19 can greatly compress the divergence angle of the laser beam and convert it into approximately parallel light, due to the physical properties of the optical lens, the collimating lens cannot achieve absolute collimation of the light beam, and when the propagation path of the light beam is too long, the light beam will gradually spread, causing energy dispersion and spot distortion, affecting subsequent light path regulation and welding precision.

[0085] The present scheme can minimize the distance between the two adjacent step mounting surfaces by arranging the laser light sources 11 on the same step mounting surface in a back-to-back and coaxial manner, greatly shortening the overall propagation path of the laser light beam from the light source to the polarizing mirror 12 after collimation and reflection. This design compensates for the technical limitations of the collimating lens from the spatial layout level, and even if the collimated light beam has a weak divergence tendency, the degree of spot spreading will be greatly reduced due to the shortened propagation distance, ensuring the energy concentration and light path consistency of the light beam when entering the polarization regulation link, and also providing space conditions for high-density integration of multiple light sources, avoiding energy loss and precision decline caused by long light path.

[0086] In the description herein, it should be understood that the terms "upper", "lower", "left", "right", and the like orientation or position relationships are only for the convenience of description and simplification of operation, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.

[0087] In the description of the present specification, the description referring to the terms "an embodiment", "an example", and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example.

[0088] In addition, it should be understood that, although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand.

[0089] The technical principles of the present application are described above in combination with specific embodiments. These descriptions are only for the purpose of explaining the principles of the present application, and cannot be interpreted in any way as a limitation on the scope of protection of the present application. Based on the explanations here, those skilled in the art can think of other specific embodiments of the present application without creative labor, and these ways will fall within the scope of protection of the present 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 polarizer (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, 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 polarizer (12) from the incident side (121); the first polarized light is reflected by the polarizer (12) and then transmitted through the first wave plate (13) to change the polarization direction and exit along a first exit light path, part of the light reflected by the work surface (4) along the first exit light path is transmitted through the first wave plate (13) to change the polarization direction again and then transmitted through the polarizer (12) from the second reflection light exit side (124); the second polarized light is transmitted through the polarizer (12) and the second wave plate (14) to change the polarization direction and exit along a second exit light path, part of the light reflected by the work surface (4) along the second exit light path is transmitted through the second wave plate (14) to change the polarization direction again and then enters the polarizer (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 exit light path and / or the second exit light path, and the first exit light path and the second exit light path are kept parallel by the reflection of the mirror lens group.

3. The semiconductor laser of claim 1, wherein, The laser module (1) comprises two groups of laser modules (1) arranged in a first direction, and the first exit light path and the second exit light path of the two groups of laser modules (1) extend in 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 exit light path, so that the end of the first exit light path extends in 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 respectively 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 directed to the second direction, so that the second polarized light is directly emitted in the second direction.

7. The semiconductor laser of claim 6, wherein, Each group of laser modules (1) further comprises a mirror lens group arranged on the second exit light path, and the mirror lens group comprises at least two second mirrors (16) arranged in parallel and facing each other, so that the end of the second exit light path is closer to the end of the first exit light path by twice reflection of the mirror lens group.

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

9. The semiconductor laser of claim 3, wherein, Each group of laser modules (1) further comprises a third reflecting mirror (17) opposite to the laser light source (11), the laser light sources (11) of the two groups of laser modules (1) being arranged coaxially and oppositely, the laser light emitted by the two groups of laser light sources (11) being oppositely projected in a direction parallel to the first direction to the corresponding third reflecting mirror (17), and after being reflected by the third reflecting mirror (17), being projected in the first direction to the corresponding polarizing mirror (12).

10. The semiconductor laser of claim 9, wherein, Further comprising a stepped heat sink (3), the stepped heat sink (3) comprising a plurality of stepped mounting surfaces of different levels, each stepped mounting surface being provided with two opposite laser light sources (11), and the two ends of each stepped mounting surface being respectively provided with the third reflecting mirror (17), so that a plurality of laser light sources (11) are simultaneously provided in each group of laser modules (1), and the laser light sources (11) of the two groups of laser modules (1) are jointly mounted on the stepped heat sink (3).

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