A ring spot laser processing system

Abstract

The present application provides an annular spot laser processing system, including a first laser light source, a first half-wave plate, a first dichroic mirror, a second laser light source, a second half-wave plate, a first reflector, a first laser crystal, a second laser crystal, a second dichroic mirror, a first lens, a second lens, a third dichroic mirror, a third lens, a fourth lens, a fourth dichroic mirror, a fifth dichroic mirror, a galvanometer mechanism, a target workpiece, and a platform. By generating a first laser beam and a second laser beam with mutually perpendicular polarization directions through the first laser light source and the second laser light source, and combining and frequency doubling the first laser beam and the second laser beam, a high-power green laser with a wavelength of 500 - 550 nm can be obtained, and a composite laser with a high-power green laser with a wavelength of 500 - 550 nm as the main laser can be generated without using a complex system structure. The entire laser processing process has high efficiency, extremely small spatter, little thermal influence on non-target processing areas, and relatively low production and manufacturing costs.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and more particularly, to an annular spot laser processing system. Background Art

[0002] In recent years, with the increasingly booming demand in the new energy industry, higher requirements have been put forward for the front-end laser processing technology. Limited by the material absorption factor, the absorption rate of traditional infrared lasers for highly reflective materials is very low, and there are many problems such as easy spattering, low efficiency, and power limited by the single-module power in welding, cutting and other precision applications, and it can no longer meet the welding and cutting of highly reflective materials such as copper materials.

[0003] The green laser has obvious advantages compared with the infrared laser by virtue of the high absorption characteristic of copper materials for green light beams. However, the laser beam of the green laser is also Gaussian distributed like that of the infrared laser. During laser processing, the temperature at the processing center is too high, which may still cause spattering during the processing and damage the electronic components around the processed workpiece. At the same time, due to a large temperature difference between the processing center and the surrounding area during the processing, a temperature gradient is formed, making the workpiece heated unevenly, resulting in various quality problems such as deformation, bubbles and cracks of the workpiece.

[0004] Based on this, it is necessary to invent an annular spot laser processing system. The output light of this laser processing system is a composite light of infrared and green light, and the composite light output form is annular spot output, which can greatly improve the processing efficiency and reduce spattering at the same time.

[0005] The currently more common annular light-assisted processing systems include two types. One is to directly set up another annular light laser to form an annular spot for assisted processing; the other is a laser processing system with an annular optical fiber created by IPG Photonics. Specifically, the optical fiber structure of the laser includes two parts: a central optical fiber and an annular optical fiber. The central beam and the annular beam are formed by controlling the central optical fiber and the annular optical fiber respectively through the laser. The central beam is used for laser processing, and the annular beam is used for assisted processing. The above two common laser processing systems are both relatively complex and have high production costs.

[0006] However, there are many problems such as the power of the green laser being limited by the single-module power. Usually, it is difficult to increase the power, or rather, it is necessary to design a complex system and consume huge production and manufacturing costs to increase the power, which is difficult to meet the power requirements and market demands for using green light as the main processing laser in laser processing application scenarios such as cutting and welding.

[0007] Based on this, it is necessary to invent a high-power laser processing system with a simple structure, low cost, convenient operation, and excellent spot quality. The high-power green laser as the main processing laser can also reduce problems such as workpiece curling, splashing, bubbles, and cracks during laser processing. Summary of the Invention

[0008] The purpose of this application is to provide an annular spot laser processing system to solve the problems raised in the above background technology.

[0009] To achieve the above purpose, this application provides the following technical solution: An annular spot laser processing system includes a first laser light source, a first half-wave plate, a first dichroic mirror, a second laser light source, a second half-wave plate, a first reflector, a first laser crystal, a second laser crystal, a second dichroic mirror, a first lens, a second lens, a third dichroic mirror, a third lens, a fourth lens, a fourth dichroic mirror, a fifth dichroic mirror, a galvanometer mechanism, a target workpiece, and a platform.

[0010] The first laser light source is mainly used to output infrared light with a wavelength of 1000 - 1100 nm as the first laser beam.

[0011] The main function of the first half-wave plate is to adjust the polarization direction of the first laser beam output from the first laser light source, which can make the first laser beam become S-polarized transmission or P-polarized transmission.

[0012] The second laser light source is mainly used to output infrared light with a wavelength of 1000 - 1100 nm as the second laser beam.

[0013] The main function of the second half-wave plate is to adjust the polarization direction of the second laser beam output from the second laser light source. Similarly, it can make the second laser beam become S-polarized transmission or P-polarized transmission. At the same time, after the first half-wave plate and the second half-wave plate adjust the respective beams, the polarization directions of the first laser beam and the second laser beam need to be perpendicular to each other.

[0014] The first reflector is mainly used to perform a total reflection turn on the second laser beam after passing through the second half-wave plate.

[0015] The first dichroic mirror mainly combines the first laser beam and the second laser beam passing through the first half-wave plate and the first reflector. The combined beam is the fundamental frequency beam.

[0016] The first laser crystal is LBO / BBO or other frequency doubling crystals, which is used to perform frequency conversion on the first laser beam. When the fundamental frequency light with a wavelength of 1000 - 1100 nm passes through this crystal and the power density reaches the nonlinear threshold, corresponding second harmonic waves, that is, frequency doubling light, will be generated. The optical frequency of the generated frequency doubling light is half of the fundamental frequency light. At this time, the generated light is green light with a wavelength of 500 - 550 nm.

[0017] The second laser crystal is also LBO / BBO or other frequency doubling crystals, which are used to perform frequency conversion on the second laser beam. The second laser crystal and the first laser crystal should be placed in a direction that rotates 90° along the optical axis direction in the laser processing system. Similarly, when the fundamental frequency light of 1000 - 1100 nm passes through this crystal and the power density reaches the nonlinear threshold, corresponding second harmonic waves, that is, frequency doubled light, will be generated. The optical frequency of the generated frequency doubled light is half of the fundamental frequency light, and the generated light is green light of 500 - 550 nm.

[0018] The second dichroic mirror separates the frequency doubled light and the residual fundamental frequency light generated after the conversion by the first laser crystal and the second laser crystal by coating a high reflection film of 500 - 550 nm and an antireflection film of 1000 - 1100 nm. The reflected 500 - 550 nm frequency doubled light after separation is the third laser beam, and the residual transmitted 1000 - 1100 nm fundamental frequency light is the fourth laser beam.

[0019] Behind the transmitted laser of the second dichroic mirror, there are a first lens and a second lens. The first lens is used to perform divergence adjustment on the 1000 - 1100 nm light beam transmitted after the dichroic separation by the second dichroic mirror. The second lens is used to perform a collimation adjustment on the light beam diverged by the first lens. The first lens and the second lens together form the first lens group.

[0020] Behind the reflected laser of the second dichroic mirror, there is a third dichroic mirror. The third dichroic mirror is at least coated with a reflection film of 500 - 550 nm, which can turn the 500 - 550 nm light beam reflected by the second dichroic mirror.

[0021] Similarly, behind the reflected and turned light of the third dichroic mirror, there are a third lens and a fourth lens. The third lens is used to perform divergence adjustment on the 500 - 550 nm light beam transmitted after the dichroic separation by the third dichroic mirror. The fourth lens is used to perform a collimation adjustment on the light beam diverged by the third lens. The third lens and the fourth lens together form the second lens group. The first lens group and the second lens group together realize the generation of a laser beam with a double-ring spot. When processing highly reflective metal materials with the laser beam with a double-ring spot, the metal material has a better absorption rate for the laser beam, has better processing accuracy, and also has smaller side effects of thermal effects.

[0022] The fourth dichroic mirror can turn the 500 - 550 nm light beam transmitted through the fourth lens again by coating a reflection film of 500 - 550 nm.

[0023] The fifth dichroic mirror is disposed behind the second lens and the fourth dichroic mirror, and adjusts the third laser beam and the fourth laser beam to the same laser output direction. Specifically, the fifth dichroic mirror is used for combining the combined light of the third laser beam and the fourth laser beam and generating an annular light spot.

[0024] The galvanometer mechanism is mainly used to integrate the combined beam output by the fifth dichroic mirror, and controls the fourth laser beam and the third laser beam to move or deflect in two mutually perpendicular directions on a plane by means of optical scanning, so that the fourth laser beam and the third laser beam act on the target workpiece according to production requirements.

[0025] The target workpiece is an element to be processed.

[0026] The platform is mainly used to carry, clamp and move the target workpiece to facilitate the processing of the target workpiece.

[0027] The annular spot laser processing system provided by the present application generates a first laser beam and a second laser beam with mutually perpendicular polarization directions through a first laser light source and a second laser light source, and combines and frequency-doubles the first laser beam and the second laser beam, so as to obtain a high-power green laser of 500-550 nm. Without using a complex system structure, a high-power green laser of 500-550 nm can be generated as the main laser composite laser to achieve the effect of composite laser processing. During the processing, the composite laser output by the system is annularly distributed, and the green laser beam is distributed in the central inner ring area. The auxiliary laser uses infrared light of 1000-1100 nm and is located in the outer ring area (the outer ring area covers the inner ring area), and is mainly used to preheat and thermally transition the working area of the target workpiece to improve the green light processing efficiency. The power density in the inner ring area is higher than that in the outer ring area. During the working process, the inner ring is a high-power green laser with a high energy density, which melts and processes the workpiece. The outer ring area does not process due to the low power density. The whole process has high efficiency, extremely small spatter, and the processing area is quickly processed. The non-target processing area has little thermal influence, greatly improving the workpiece processing accuracy, yield and efficiency. Moreover, the optical-to-optical conversion efficiency of the laser is extremely high, with basically no other energy loss, greatly improving the energy utilization, and the production and manufacturing cost will also be lower. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1The first schematic structural diagram of the annular spot laser processing system provided by this application;

[0030] Figure 2 The second schematic structural diagram of the annular spot laser processing system provided by this application;

[0031] Figure 3 The third schematic structural diagram of the annular spot laser processing system provided by this application;

[0032] Figure 4 The fourth schematic structural diagram of the annular spot laser processing system provided by this application;

[0033] Figure 5 The fifth schematic structural diagram of the annular spot laser processing system provided by this application;

[0034] Figure 6 The sixth schematic structural diagram of the annular spot laser processing system provided by this application.

[0035] Figure 7 The seventh schematic structural diagram of the annular spot laser processing system provided by this application;

[0036] Figure 8 The eighth schematic structural diagram of the annular spot laser processing system provided by this application.

[0037] Reference numerals:

[0038] 1. First laser light source, 2. First half-wave plate, 3. First dichroic mirror, 4. Second laser light source, 5. Second half-wave plate, 6. First reflector, 7. First laser crystal, 8. Second laser crystal, 9. Second dichroic mirror, 10. First lens, 11. Second lens, 12. Third dichroic mirror, 13. Third lens, 14. Fourth lens, 15. Second reflector, 16. Third reflector, 17. Fourth dichroic mirror, 18. Fifth dichroic mirror, 19. Galvo mechanism, 20. Target workpiece, 21. Platform, 22. Fourth reflector, 23. Fifth lens, 24. Window plate, L. Fundamental frequency beam, L'. Composite beam, L1. First laser beam, L2. Second laser beam, L3. Third laser beam, L4. Fourth laser beam, L5. Fifth laser beam, L6. Sixth laser beam, L7. Seventh laser beam. Detailed implementation manners

[0039] To enable those skilled in the art to better understand the solution of this application, the following further detailed description of this application will be given in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this application, rather than a limitation on the scope of the rights of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application.

[0040] Please refer to Figure 1 , Figure 1 , which is the first structural schematic diagram of the annular spot laser processing system provided by this application. The annular spot laser processing system includes: a first laser light source 1, a first half-wave plate 2, a first dichroic mirror 3, a second laser light source 4, a second half-wave plate 5, a first reflector 6, a first laser crystal 7, a second laser crystal 8, a second dichroic mirror 9, a first lens 10, a second lens 11, a third dichroic mirror 12, a third lens 13, a fourth lens 14, a fourth dichroic mirror 17, a fifth dichroic mirror 18, a galvanometer mechanism 19, a target workpiece 20, and a platform 21.

[0041] The first laser light source 1 is mainly used to output a first laser beam L1 with a wavelength of 1000 - 1100 nm. The first laser light source 1 can be a fiber laser or a semiconductor laser.

[0042] The first half-wave plate 2 is located behind the first laser light source 1. Its main function is to adjust the polarization direction of the first laser beam L1 output from the first laser light source 1, which can make the first laser beam L1 become S-polarized transmission or P-polarized transmission. In this embodiment, P-polarized transmission is taken as an example.

[0043] The second laser light source 4 is mainly used to output a second laser beam L2 with a wavelength of 1000 - 1100 nm. The second laser light source 4 can also be a fiber laser or a semiconductor laser.

[0044] The second half-wave plate 5 is located behind the second laser light source 4. Its main function is to adjust the polarization direction of the second laser beam L2 output from the second laser light source 4, which can make the second laser beam L2 become S-polarized transmission or P-polarized transmission. In this embodiment, S-polarized transmission is taken as an example. That is, after the first half-wave plate 2 and the second half-wave plate 5 adjust the respective beams, the polarization directions of the first laser beam L1 and the second laser beam L2 are perpendicular to each other.

[0045] The first reflector 6 is located behind the second half-wave plate 5 and is coated with a polarization reflection film. It is mainly used to perform a total reflection turn on the second laser beam L2 after passing through the second half-wave plate 5.

[0046] The first dichroic mirror 3 is located behind the first half-wave plate 2 and the first reflector 6, and mainly combines the first laser beam L1 and the second laser beam L2 that have passed through the first half-wave plate 2 and the first reflector 6. The combined beam is the fundamental frequency beam L.

[0047] The first laser crystal 7 is located behind the first dichroic mirror 3 and is an LBO / BBO or other frequency doubling crystal, which is used to perform frequency conversion on the first laser beam L1. When the fundamental frequency light of 1000 - 1100 nm passes through the first laser crystal 7 and the power density reaches the nonlinear threshold, the corresponding second harmonic will be generated, and at this time, green light of 500 - 550 nm is generated.

[0048] The second laser crystal 8 is located behind the first laser crystal 7 and is also an LBO / BBO or other frequency doubling crystal, which is used to perform frequency conversion on the second laser beam L2. The second laser crystal 8 and the first laser crystal 7 should be placed in a direction rotated 90° from each other along the optical axis direction in the laser processing system, and the fast axis direction should take into account the polarization direction of the beam after passing through the first half-wave plate 2 and the second half-wave plate 5. At this time, good frequency doubling effects of both the second laser crystal 8 and the first laser crystal 7 can be taken into account. Similarly, when the fundamental frequency light of 1000 - 1100 nm passes through the second laser crystal 8 and the power density reaches the nonlinear threshold, green light of 500 - 550 nm is generated.

[0049] The second dichroic mirror 9 is located behind the second laser crystal 8. By coating a high-reflection film of 500 - 550 nm and an antireflection film of 1000 - 1100 nm, it separates the frequency doubled light generated after the conversion by the first laser crystal 7 and the second laser crystal 8 from the residual fundamental frequency beam L. The frequency doubled light of 500 - 550 nm reflected after separation is the third laser beam L3, and the residual fundamental frequency beam L of 1000 - 1100 nm transmitted is the fourth laser beam L4.

[0050] Behind the transmitted laser of the second dichroic mirror 9, there are a first lens 10 and a second lens 11. The first lens 10 is generally a concave lens, which is used to perform divergence adjustment on the 1000 - 1100 nm beam transmitted after the dichroic separation by the second dichroic mirror 9. The second lens 11 is generally a convex lens, which is used to perform a collimation adjustment on the beam diverged by the first lens 10. The first lens 10 and the second lens 11 together form a first lens group, and the first lens group performs a fixed magnification on the beam size of the fourth laser beam L4 after the dichroic separation by the second dichroic mirror 9.

[0051] Behind the reflected laser of the second dichroic mirror 9, there is a third dichroic mirror 12. The third dichroic mirror 12 is at least coated with a reflection film of 500 - 550 nm, which can deflect the 500 - 550 nm beam reflected by the second dichroic mirror 9.

[0052] Behind the reflection-turned third dichroic mirror 12, there are a third lens 13 and a fourth lens 14. The third lens 13 is generally a concave lens, which is used to diverge and adjust the 500 - 550 nm light beam transmitted after being color-separated by the third dichroic mirror 12. The fourth lens 14 is generally a convex lens, which is used to collimate the light beam diverged by the third lens 13. The third lens 13 and the fourth lens 14 together form the second lens group. The second lens group performs a fixed magnification of the beam size of the 500 - 550 nm light beam after being color-separated by the third dichroic mirror 12, and the magnification factor of the second lens group for the light spot is less than that of the first lens group. To achieve a small-spot laser beam centered on the third laser beam L3 and a large-spot beam with the fourth laser beam L4 as the periphery. Because when processing highly reflective metal materials with the 500 - 550 nm third laser beam L3, the metal material has a better absorption rate for the laser beam, has better processing accuracy, and also has smaller side effects of thermal effects.

[0053] The fourth dichroic mirror 17 is located behind the fourth lens 14, and can turn the 500 - 550 nm light beam transmitted through the fourth lens 14 again by coating a 500 - 550 nm reflection film.

[0054] The fifth dichroic mirror 18 is arranged behind the second lens 11 and the fourth dichroic mirror 17, and adjusts the third laser beam L3 and the fourth laser beam L4 to the same laser output direction. Specifically, the fifth dichroic mirror 18 is used for combining the third laser beam L3 and the fourth laser beam L4 and generating an annular light spot. That is, the 500 - 550 nm third laser beam L3 transmitted through the fourth dichroic mirror 17 and the 1000 - 1100 nm fourth laser beam L4 transmitted through the second lens 11 are combined at the fifth dichroic mirror 18, and the combined laser forms a composite beam L' with an annular light spot.

[0055] Behind the fifth dichroic mirror 18, there is a galvanometer mechanism 19. The galvanometer mechanism 19 is mainly used to integrate the composite beam L' transmitted by the fifth dichroic mirror 18, and controls the movement or deflection of the fourth laser beam L4 and the third laser beam L3 in two mutually perpendicular directions on a plane by means of optical scanning, so that the fourth laser beam L4 and the third laser beam L3 act on the target workpiece 20 according to the production requirements.

[0056] The target workpiece 20 is the component to be processed.

[0057] The platform 21 is mainly used to carry or clamp and move the target workpiece 20 to facilitate the processing of the target workpiece 20.

[0058] Further, in order to reduce the power loss of the system and improve the optical-optical conversion efficiency of the laser processing system, both sides of the first half-wave plate 2 and the second half-wave plate 5 are coated with an antireflection film with a wavelength range of 1000 - 1100 nm.

[0059] Further, in order to improve the reflectivity, the first mirror 6 is coated with a polarization reflection film on the surface close to the second half-wave plate 5. When the light after passing through the second half-wave plate 5 is transmitted with S polarization, the first mirror 6 is coated with an HR film with a wavelength range of 1000 - 1100 nm for S polarization on the surface close to the second half-wave plate 5, and Rs > 99.7%.

[0060] Further, in order to improve the beam combining efficiency, the first dichroic mirror 3 is coated with a polarization dichroic film system; for example, when the first half-wave plate 2 transmits P-polarized light and the first mirror 6 reflects S-polarized light after reflection, the first dichroic mirror 3 is coated with a P-polarized antireflection film with a wavelength range of 1000 - 1100 nm on the surface close to the first half-wave plate 2, and a P-polarized antireflection film with a wavelength range of 1000 - 1100 nm and an S-polarized high-reflection film on the surface close to the first mirror 6.

[0061] Further, the first laser crystal 7 is coated with an antireflection film with a wavelength range of 1000 - 1100 nm on the side close to the first half-wave plate 2, and an antireflection film with a wavelength range of 500 - 550 nm and 1000 - 1100 nm on the side far from the first half-wave plate 2. Both sides of the second laser crystal 8 are coated with an antireflection film with a wavelength range of 500 - 550 nm and 1000 - 1100 nm.

[0062] Further, the second dichroic mirror 9 is coated with a high-reflection film with a wavelength range of 500 - 550 nm and an antireflection film with a wavelength range of 1000 - 1100 nm on the surface side close to the second laser crystal 8. At the same time, it is coated with an antireflection film with a wavelength range of 1000 - 1100 nm on the surface side far from the second laser crystal 8.

[0063] Further, in order to reduce the power loss of the system and improve the optical-optical conversion efficiency of the laser processing system, the first lens 10 and the second lens 11 are coated with an antireflection film with a wavelength range of 1000 - 1100 nm, and the third lens 13 and the fourth lens 14 are coated with an antireflection film with a wavelength range of 500 - 550 nm.

[0064] Further, as Figure 1 shown, the fifth dichroic mirror 18 can adjust the third laser beam L3 and the fourth laser beam L4 to the same laser output direction by coating a high-reflection film with a wavelength range of 500 - 550 nm and an antireflection film with a wavelength range of 1000 - 1100 nm (in other embodiments, the effect of adjusting the third laser beam L3 and the fourth laser beam L4 to the same laser output direction can also be achieved by coating other film layers and combining with other placement angles).

[0065] Further, the power densities of the third laser beam L3 and the fourth laser beam L4 can also be autonomously adjusted by simultaneously changing the conversion efficiencies of the first laser crystal 7 and / or the second laser crystal 8 to meet different application requirements. For example, by changing the temperature environment and the placement angles of the first laser crystal 7 and the second laser crystal 8. Therefore, compared with the existing composite laser processing system, the laser processing system of the present application does not require an additional power density adjustment mechanism.

[0066] Please refer to Figure 2 , Figure 2 FIG. 2 is a second schematic structural diagram of the annular spot laser processing system provided by the present application. Based on the laser processing system in Figure 1 , the annular spot laser processing system further includes a fifth lens 23, which is located between the first dichroic mirror 3 and the first laser crystal 7. A plano-convex lens is usually adopted to converge the energy of the fundamental frequency beam L, improve the energy density or power density of the fundamental frequency beam L. After the energy density or power density of the fundamental frequency beam L is improved, the frequency conversion efficiency of the subsequent fundamental frequency beam L into the second harmonic light will also be greatly improved.

[0067] Please refer to Figure 3 , Figure 3 FIG. 3 is a third schematic structural diagram of the annular spot laser processing system provided by the present application. Based on the laser processing system in Figure 2 , the annular spot laser processing system further includes a window plate 24, which is located between the fifth dichroic mirror 18 and the galvanometer mechanism 19. It is mainly used to seal the annular spot laser processing system, isolate the composite light and the annular light generation system from the external environment, so as to achieve a clean laser generation environment.

[0068] Further, to reduce system loss, the window plate 24 is generally coated with an antireflection film on both sides, with an antireflection film of 1000 - 1100 nm and an antireflection film of 500 - 550 nm.

[0069] Further, to reduce the influence on the output laser beam, the window plate 24 can adopt a double-ended plano lens. The beam output through the window plate 24 includes a third laser beam L3 of 500 - 550 nm located in the center and a fourth laser beam L4 of 1000 - 1100 nm located in the outer ring. Among them, the output spot diameter of the third laser beam L3 is r1, and the output spot diameter of the fourth laser beam L4 is r2, where r2 > r1. In the laser processing system, the inner and outer ring size difference between r1 and r2 can be achieved by adjusting the positions of the first lens 10, the second lens 11, the third lens 13, and the fourth lens 14 in the laser processing system.

[0070] Please refer to Figure 4 , Figure 4This is the fourth structural schematic diagram of the annular spot laser processing system provided by this application. The annular spot laser processing system, on the basis of the laser processing system shown in Figure 1 , further includes a second reflector 15 and a third reflector 16. The second reflector 15 and the third reflector 16 are located between the third dichroic mirror 12 and the fourth dichroic mirror 17. When the third dichroic mirror 12 performs polarization beam splitting on the 500 - 550 nm light beam reflected by the second dichroic mirror 9 to achieve the spot effect of three rings, the second reflector 15 and the third reflector 16 can be used to turn the transmission direction of the laser beam to adapt to more application scenarios, and facilitate the introduction of the laser beam into the target application system. At the same time, stray light is further filtered out.

[0071] To improve the purity of beam splitting, the third dichroic mirror 12 is coated with a polarization beam splitting film for the 500 - 550 nm light beam. Specifically, on the surface close to the second dichroic mirror 9, an S - polarization reflection film and a P - polarization antireflection film for 500 - 550 nm are coated, and on the surface far from the second dichroic mirror 9, a P - polarization antireflection film for 500 - 550 nm is coated. The laser beam reflected by the third dichroic mirror 12 is the fifth laser beam L5, and the laser beam transmitted by the third dichroic mirror 12 is the sixth laser beam L6.

[0072] The second reflector 15 and the third reflector 16 perform polarization total reflection on the light beam split by the third dichroic mirror 12. To improve the reflectivity, the second reflector 15 and the third reflector 16 are coated with a polarization reflection film, specifically, a P - polarization 500 - 550 nm high - reflection film.

[0073] In this embodiment, the sixth laser beam L6 transmitted by the third dichroic mirror 12 is the inner - ring beam with a spot diameter of r4, and the main laser component is the P - polarization beam of 500 - 550 nm. The fifth laser beam L5 reflected by the third dichroic mirror 12 is the middle - ring beam with a spot diameter of r3, and the main laser component is the S - polarization beam of 500 - 550 nm. The fourth laser beam L4 is still the outer - ring beam of 1000 - 1100 nm, and its spot diameter is r2, where r2 > r3 > r4. Generally, the proportion of the outer - ring laser is very small and usually does not perform processing operations on the target workpiece 20. It is mainly used to preheat and thermally transition the target workpiece 20 to reduce the irreversible damage to the target workpiece 20 caused by the thermal impact during the processing. The energy density of the middle - ring laser is higher than that of the outer - ring laser, and it first completes the melting effect on the target workpiece 20. The energy density of the inner - ring laser is the highest. Then the target workpiece 20 starts to form a molten state, and the inner - ring laser quickly completes the processing in the inner - ring area. When processing with such a three - ring spot, compared with a single - mode normal - output single laser or a double - ring laser, it significantly has less spatter and higher processing efficiency, which is extremely beneficial to precision processing.

[0074] In this embodiment, the fourth dichroic mirror 17 performs polarization beam combination on the fifth laser beam L5 and the sixth laser beam L6 with wavelengths of 500 - 550 nm that are transmitted by the fourth lens 14 and reflected by the third mirror 16. The combined laser beam is the seventh laser beam L7.

[0075] Further, to improve the efficiency of beam combination and splitting, the fourth dichroic mirror 17 is coated with a polarization beam splitting film for 500 - 550 nm. Specifically, the surface close to the third mirror 16 is coated with an anti - reflection film for P - polarization at 500 - 550 nm, and the surface far from the third mirror 16 is coated with an S - polarization reflection film and an anti - reflection film for P - polarization at 500 - 550 nm.

[0076] In Figure 4 the illustrated embodiment, the fifth dichroic mirror 18 adjusts the seventh laser beam L7 and the fourth laser beam L4 to the same laser output direction. Specifically, the fifth dichroic mirror 18 is used for beam combination of the composite light of the seventh laser beam L7 and the fourth laser beam L4 and generation of an annular light spot. That is, the seventh laser beam L7 with a wavelength of 500 - 550 nm transmitted by the fourth dichroic mirror 17 and the fourth laser beam L4 with a wavelength of 1000 - 1100 nm transmitted by the second lens 11 are combined at the fifth dichroic mirror 18, and the combined laser forms a composite beam L' with an annular light spot.

[0077] Please refer to Figure 5 , Figure 5 which is the fifth structural schematic diagram of the annular - spot laser processing system provided by this application. Based on the laser processing system shown in Figure 1 , the system further includes a fourth mirror 22. The fourth mirror 22 is located between the fifth dichroic mirror 18 and the galvanometer mechanism 19, and is mainly used to deflect the transmission direction of the composite laser beam to adapt to more application scenarios, facilitate the introduction of the laser beam into the target application system, and further filter out stray light.

[0078] As Figure 5 shown, the fifth dichroic mirror 18 is disposed behind the fourth lens 14. The fifth dichroic mirror 18 can adjust the third laser beam L3 and the fourth laser beam L4 to the same laser output direction by being coated with a high - reflection film for 1000 - 1100 nm and an anti - reflection film for 500 - 550 nm (the coating of the fifth dichroic mirror 18 here is different from that of the fifth dichroic mirror 18 in the Figure 1 laser processing system), and the fourth mirror 22 is coated with a high - reflection film for 1000 - 1100 nm and a high - reflection film for 500 - 550 nm.

[0079] Further, to reduce the negative impact on the output laser beam, the fourth mirror 22 uses a plane lens.

[0080] Please refer toFigure 6 , Figure 6 is the sixth structural schematic diagram of the annular spot laser processing system provided by this application. Based on the laser processing system shown in Figure 5 , the annular spot laser processing system further includes a fifth lens 23, and the fifth lens 23 is located between the first dichroic mirror 3 and the first laser crystal 7. The principle and effect of the fifth lens 23 are the same as those in the laser processing system shown in Figure 2 , and will not be elaborated here.

[0081] Please refer to Figure 7 , Figure 7 is the seventh structural schematic diagram of the annular spot laser processing system provided by this application. Based on the laser processing system shown in Figure 6 , the annular spot laser processing system further includes a window plate 24, and the window plate 24 is located between the galvanometer mechanism 19 and the fourth mirror 22. Similarly, the principle and effect of the window plate 24 in Figure 7 are the same as those in the laser processing system shown in Figure 3 , and will not be elaborated here.

[0082] Please refer to Figure 8 , Figure 8 is the eighth structural schematic diagram of the annular spot laser processing system provided by this application. Based on the laser processing system shown in Figure 7 , the annular spot laser processing system further includes a second mirror 15 and a third mirror 16, and the second mirror 15 and the third mirror 16 are located between the third dichroic mirror 12 and the fourth dichroic mirror 17. When the third dichroic mirror 12 performs polarization beam splitting on the 500 - 550 nm light beam reflected by the second dichroic mirror 9 to achieve the laser processing effect of a three-ring spot, the second mirror 15 and the third mirror 16 play a role in turning the transmission direction of the laser beam to adapt to more application scenarios and facilitate the introduction of the laser beam into the target application system. At the same time, stray light is further filtered. Similarly, the principle and effect of the second mirror 15 and the third mirror 16 in Figure 8 are the same as those in the laser processing system shown in Figure 4 , and will not be elaborated here.

[0083] The melting depth of the laser processing system of this application is adjustable. Since the component laser beams of the output composite laser beam respectively have their own divergence angle and other parameter adjustment systems, the parameters of the laser processing system are adjusted in real time through external control. By adjusting or compensating the processing parameters during the laser processing, synchronous processing of different melting depths or dynamic transformation processing of different melting depths can be achieved, which can meet the requirements of various high-difficulty processing scenarios.

[0084] It should be noted that the technical solutions of the above embodiments of the present application can be combined. If there is no inclusion relationship between the embodiments, unless there is an obviously contradictory solution, otherwise, it is not limited to the scope described in a single embodiment, but can be combined with each other to form a new embodiment. In this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes the inherent elements thereof. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element. In addition, the parts of the above technical solutions provided by the embodiments of the present application that are consistent with the corresponding technical solutions in the prior art in terms of implementation principles are not described in detail to avoid excessive elaboration.

[0085] Specific examples are used in this article to illustrate the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present application, several improvements and modifications can be made to the present application, and the various embodiments of the present application can be combined, and these improvements, modifications and combinations also fall within the protection scope of the claims of the present application.

Claims

1. A ring spot laser processing system, characterized in that , including: A first laser light source (1), a first half-wave plate (2), a first dichroic mirror (3), a second laser light source (4), a second half-wave plate (5), a first reflector (6), a first laser crystal (7), a second laser crystal (8), a second dichroic mirror (9), a first lens (10), a second lens (11), a third dichroic mirror (12), a third lens (13), a fourth lens (14), a fourth dichroic mirror (17), a fifth dichroic mirror (18), a galvanometer mechanism (19), a target workpiece (20), a platform (21); The first laser light source (1) is used to output a first laser beam (L1) with a wavelength of 1000 - 1100 nm; The first half-wave plate (2) is located behind the first laser light source (1) to adjust the polarization direction of the first laser beam (L1); The second laser light source (4) is used to output a second laser beam (L2) with a wavelength of 1000 - 1100 nm; The second half-wave plate (5) is located behind the second laser light source (4) to adjust the polarization direction of the second laser beam (L2), such that the polarization directions of the first laser beam (L1) and the second laser beam (L2) are perpendicular to each other; The first reflector (6) is located behind the second half-wave plate (5) to perform a total reflection turn on the second laser beam (L2) after passing through the second half-wave plate (5); The first dichroic mirror (3) is located behind the first half-wave plate (2) and the first reflector (6) to combine the first laser beam (L1) and the second laser beam (L2) passing through the first half-wave plate (2) and the first reflector (6), and the combined beam is the fundamental frequency beam (L); The first laser crystal (7) is located behind the first dichroic mirror (3) and is an LBO / BBO frequency doubling crystal, which is used to perform frequency conversion on the first laser beam (L1) to generate green light with a wavelength of 500 - 550 nm; The second laser crystal (8) is located behind the first laser crystal (7) and is also an LBO / BBO frequency doubling crystal, which is used to perform frequency conversion on the second laser beam (L2). The second laser crystal (8) and the first laser crystal (7) should be placed in a direction rotated 90° along the optical axis direction in the laser processing system, and also generate green light with a wavelength of 500 - 550 nm; The second dichroic mirror (9) is located behind the second laser crystal (8). By coating a high reflection film with a wavelength of 500 - 550 nm and an antireflection film with a wavelength of 1000 - 1100 nm, it separates the green light generated after the conversion by the first laser crystal (7) and the second laser crystal (8) from the residual fundamental frequency beam (L). The reflected green light with a wavelength of 500 - 550 nm is the third laser beam (L3), and the residual transmitted fundamental frequency beam (L) with a wavelength of 1000 - 1100 nm is the fourth laser beam (L4); Behind the transmitted laser of the second dichroic mirror (9), there are a first lens (10) and a second lens (11). The first lens (10) is used to diverge and adjust the 1000 - 1100nm light beam transmitted after color separation by the second dichroic mirror (9), and the second lens (11) is used to collimate and adjust the light beam diverged by the first lens (10). The first lens (10) and the second lens (11) together form a first lens group, and the first lens group performs a fixed - magnification amplification of the beam size of the fourth laser beam (L4) after color separation by the second dichroic mirror (9). Behind the reflected laser of the second dichroic mirror (9), there is a third dichroic mirror (12). The third dichroic mirror (12) is coated with at least a reflection film of 500 - 550nm, and turns the 500 - 550nm light beam reflected by the second dichroic mirror (9). Behind the reflected and turned light of the third dichroic mirror (12), there are a third lens (13) and a fourth lens (14). The third lens (13) is used to diverge and adjust the 500 - 550nm light beam transmitted after color separation by the third dichroic mirror (12), and the fourth lens (14) is used to collimate and adjust the light beam diverged by the third lens (13). The third lens (13) and the fourth lens (14) together form a second lens group. The second lens group performs a fixed - magnification amplification of the beam size of the third laser beam (L3) after color separation by the third dichroic mirror (12), and the magnification of the second lens group for the light spot is less than that of the first lens group. The fourth dichroic mirror (17) is located behind the fourth lens (14), and turns the 500 - 550nm light beam transmitted through the fourth lens (14) again by coating a 500 - 550nm reflection film. The fifth dichroic mirror (18) is arranged behind the second lens (11) and the fourth dichroic mirror (17), adjusts the third laser beam (L3) and the fourth laser beam (L4) to the same laser output direction, and combines them. The combined laser forms a composite beam (L′) with an annular light spot. Behind the fifth dichroic mirror (18), there is a galvanometer mechanism (19). The galvanometer mechanism (19) is used to integrate the composite beam (L′) output from the fifth dichroic mirror (18), and controls the movement or deflection of the fourth laser beam (L4) and the third laser beam (L3) in two mutually perpendicular directions on a plane by means of optical scanning. The target workpiece (20) is an element to be processed. The platform (21) is used to carry, clamp, and move the target workpiece (20).

2. The annular spot laser processing system according to claim 1, wherein , the fifth dichroic mirror (18) adjusts the third laser beam (L3) and the fourth laser beam (L4) to the same laser output direction by coating a 500 - 550nm high - reflection film and a 1000 - 1100nm anti - reflection film. The output light spot diameter of the third laser beam (L3) is r1, and the output light spot diameter of the fourth laser beam (L4) is r2, and r2 > r1.

3. The annular spot laser processing system according to claim 1, wherein , further comprising a fifth lens (23) located between the first dichroic mirror (3) and the first laser crystal (7) for energy convergence of the fundamental frequency beam (L).

4. The annular spot laser processing system according to claim 1, wherein Further comprising a window plate (24) located between the fifth dichroic mirror (18) and the galvanometer mechanism (19) for sealing the annular spot laser processing system.

5. The annular spot laser processing system according to claim 1, characterized in that , further comprising a second mirror (15) and a third mirror (16) located between the third dichroic mirror (12) and the fourth dichroic mirror (17). The third dichroic mirror (12) is coated with an S-polarized reflective film and a P-polarized antireflection film with a wavelength of 500 - 550 nm on the surface close to the second dichroic mirror (9), and a P-polarized antireflection film with a wavelength of 500 - 550 nm on the surface far from the second dichroic mirror (9). The laser beam reflected by the third dichroic mirror (12) is the fifth laser beam (L5), and the laser beam transmitted by the third dichroic mirror (12) is the sixth laser beam (L6) to achieve a three-ring spot effect.

6. The annular spot laser processing system according to claim 1, wherein , further comprising a fourth mirror (22) located between the fifth dichroic mirror (18) and the galvanometer mechanism (19) for steering the transmission direction of the composite laser beam. At this time, the fifth dichroic mirror (18) adjusts the third laser beam (L3) and the fourth laser beam (L4) to the same laser output direction by coating a high-reflection film with a wavelength of 1000 - 1100 nm and an antireflection film with a wavelength of 500 - 550 nm.

7. The annular spot laser processing system according to claim 6, wherein , further comprising a fifth lens (23) located between the first dichroic mirror (3) and the first laser crystal (7).

8. The annular spot laser processing system according to claim 7, wherein, Further comprising a window plate (24) located between the galvanometer mechanism (19) and the fourth mirror (22).

9. The annular spot laser processing system according to claim 8, wherein Further comprising a second mirror (15) and a third mirror (16) located between the third dichroic mirror (12) and the fourth dichroic mirror (17).

10. The annular spot laser processing system according to claim 1, wherein, Adjust the power density of the third laser beam (L3) and the fourth laser beam (L4) by changing the conversion efficiency of the first laser crystal (7) and / or the second laser crystal (8).

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