A laser pointing stabilization control system, a scanning processing system and a control method
Patent Information
- Application Number
- CN202611278560.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-21
- Publication Date
- 2026-10-13
AI Technical Summary
（1）长期抗漂移能力不足；
[0022]相较于现有技术，本发明的激光指向稳定控制系统、扫描加工系统及控制方法，其中，激光指向稳定控制系统通过设置中央控制器读取第一探测单元和第二探测单元输出的光束的质心位置信号，输出驱动信号驱动至第一校正执行单元和第二校正执行单元进行X、Y双轴微角度偏转，对光束指向偏移进行实时补偿，形成全闭环控制回路，对慢漂移进行持续校正，维持光束指向的长期稳定。激光扫描加工系通过设置中央控制器控制时序与激光器出光控制、振镜扫描动作协同匹配，在激光器断续出光、振镜动态扫描的加工过程中，稳定闭环回路可持续工作，校正动作与扫描动作解耦，确保动态加工全流程中光束指向精度稳定，且具备优异的长期抗漂移能力，有效提升加工精度与产品良率。
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Figure CN122902073A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of beam pointing stabilization control technology, and in particular to a laser pointing stabilization control system, a scanning processing system, and a control method. Background Technology
[0002] The pointing stability of lasers in optical systems primarily affects the accuracy of optical processes or techniques; higher stability often translates to higher processing precision or measurement results. With the development of modern industry, the pointing stability of lasers has become increasingly important in practical applications such as laser processing, laser communication, and target designation. Existing laser pointing devices generally employ passive vibration isolation beam stabilization schemes, open-loop temperature compensation beam correction schemes, or short-period closed-loop beam pointing correction schemes.
[0003] However, the aforementioned laser stabilization pointing device has the following main drawbacks: (1) Insufficient long-term anti-drift capability; (2) Poor compatibility with scanning processing optical paths; (3) There is a problem of attenuation of the correction effect under high power.
[0004] Therefore, it is necessary to provide a laser pointing stabilization control system, scanning processing system, and control method that can achieve submicron stabilization at the hundred-hour level and is compatible with dynamic scanning processing, in order to solve the above problems. Summary of the Invention
[0005] This invention provides a laser pointing stabilization control system, scanning processing system, and control method that can achieve submicron stabilization at the level of hundreds of hours (i.e., the RMS of beam pointing deviation is in the few micrometers under more than 100 hours of continuous testing), is compatible with femtosecond laser dynamic scanning processing conditions, and significantly improves processing accuracy and morphology consistency.
[0006] The technical solution adopted in this invention is as follows: a laser pointing stabilization control system, which includes: a central controller, a laser, a beam expander, a first reflector, a first correction execution unit, a second reflector, a third reflector, and a fourth reflector arranged sequentially along the beam transmission direction; The laser is used to output high-quality pulsed laser; the beam expander is used to expand, collimate, and control the divergence angle of the beam output by the laser; the first reflector, the second reflector, the third reflector, and the fourth reflector are all used to adjust the transmission direction of the beam; A first detection unit is provided on the light-transmitting side of the second correction execution unit, and a second detection unit is provided on the light-transmitting side of the third reflector; a portion of the light beam passing through the second correction execution unit is incident on the first detection unit, and a portion of the light beam passing through the third reflector is incident on the second detection unit; The first correction execution unit and the second correction execution unit are used to compensate for the pointing offset of the beam in real time based on the centroid position signal of the beam collected by the first detection unit and the second detection unit, respectively. The central controller is electrically connected to the laser, the first correction execution unit, the second correction execution unit, the first detection unit, and the second detection unit.
[0007] Furthermore, a light spot analyzer is provided on the light-transmitting side of the fourth reflector. The light spot analyzer is electrically connected to the central controller and is used to monitor the actual beam drift.
[0008] Furthermore, both the first correction execution unit and the second correction execution unit are electrically controlled reflectors or piezoelectrically driven fast deflectors; both the first detection unit and the second detection unit are spot centroid detectors or position-sensitive detectors.
[0009] The present invention further provides the following technical solutions: A laser scanning processing system includes: a laser pointing and stabilizing control system and a galvanometer and a field mirror sequentially disposed after the laser pointing and stabilizing control system along the beam transmission direction, wherein the galvanometer and the field mirror constitute a scanning processing optical path; the galvanometer is used to realize high-speed scanning within the processing area of the field mirror; and the galvanometer is electrically connected to the central controller; the field mirror is used to focus the beam onto the surface of the sample.
[0010] This invention also provides the following technical solutions: A laser pointing stabilization control method, using the aforementioned laser scanning processing system, includes the following steps: S1: The central controller issues a command to start the laser and emit a beam. The beam travels along the optical path and is reflected by the second reflector to the second correction execution unit. The second correction execution unit then reflects the beam to the third reflector. At the same time, part of the beam passes through the second correction execution unit and is incident on the first detection unit, which collects the X-axis and Y-axis position data of the beam. The beam is then reflected by the third reflector and enters the fourth reflector. At the same time, part of the beam passes through the third reflector and is incident on the second detection unit, which collects the X-axis and Y-axis position data of the beam. S2: The central controller reads the X-axis and Y-axis position data of the beam collected by the first and second detection units at a fixed sampling frequency, compares it with the preset reference position to calculate the deviation, and after digital filtering and closed-loop control algorithm calculation, outputs a drive signal to the first and second correction execution units to drive the first and second correction execution units to perform micro-angle deflection on the X-axis and Y-axis, to compensate for the beam pointing deviation in real time, form a full closed-loop control loop, and continuously correct the slow drift.
[0011] Furthermore, in step S2, the reference position is set through two steps: optical design and calibration verification. First, optical design and positioning are performed: based on the target offset magnification, the optical path lengths from the first correction execution unit to the first detection unit and from the second correction execution unit to the second detection unit are calculated respectively. Along the beam transmission direction, at the incident front end of the scanning processing optical path, the mounting reference positions of the first and second detection units are determined. Then, calibration and verification are performed: After the first and second detection units are installed, a reference beam with a known deflection is input into the first and second detection units to calibrate the correspondence between the offset output by the first and second detection units and the actual offset of the sample's processing surface. After confirming that the detection accuracy meets the requirements, the position setting is completed.
[0012] Furthermore, in step S2, the closed-loop control algorithm includes moving average digital filtering calculation, position and angle deviation calculation coupled by the first and second detection units, and PI closed-loop control algorithm.
[0013] Further, the moving average digital filtering operation is as follows: the original sampling data of the first detection unit and the second detection unit are respectively subjected to moving average filtering processing to form two filtered position data; wherein, the filtered coordinates of the first detection unit are:
[0014] Coordinates after filtering by the second detection unit:
[0015] In the formula, x 1，i y 1，i These are the original centroid coordinates along the X and Y axes of the first detection unit during the i-th sampling; x 2，i y 2，i These are the original centroid coordinates along the X and Y axes of the second detection unit during the i-th sampling; x 1，k , 1，k x represents the centroid coordinates of the first detection unit after the k-th filtering. 2，k , 2，k is the centroid coordinate of the second detection unit after the k-th filtering; N is the number of sampling points in the sliding window.
[0016] Furthermore, the coupled calculation of position and angle deviations by the first and second detection units is as follows: using the distance between the first and second detection units along the optical axis, the position and angle deviations of the beam are obtained through coupled calculation of the two filtered position data, where... Positional deviation:
[0017] Angle deviation:
[0018] In the formula, Δx and Δy are the X-axis and Y-axis position deviations of the light beam at the first detection unit; θ x θ y L represents the angular deviation of the beam in the X and Y axes; L is the distance between the first and second detection units along the optical axis.
[0019] Furthermore, the PI closed-loop control algorithm is as follows: PI control calculations are performed on the calculated position and angle deviations respectively, outputting two independent control quantities to drive the first and second correction execution units respectively, collaboratively completing the real-time correction of beam position and angle drift, forming a full closed-loop control circuit. The Y-axis control logic is consistent with the X-axis logic, including: (a) Deviation calculation:
[0020] (b) Control output:
[0021] In the formula, x e y e The preset beam reference position coordinates; θ x， e θ y， e The preset beam reference angle; e x (k), e y (k) represents the positional deviation along the X and Y axes at time k; e_θ x (k), e_θ y (k) represents the angular deviation in the X-axis and Y-axis directions at time k; K p1K i1 These are the proportional and integral coefficients of the position correction loop, respectively; K p2 K i2 These are the proportional coefficient and integral coefficient of the angle correction loop, respectively; u1(k) is the drive control quantity output to the first correction execution unit; u2(k) is the drive control quantity output to the second correction execution unit.
[0022] Compared to existing technologies, the laser pointing stabilization control system, scanning processing system, and control method of this invention, wherein the laser pointing stabilization control system reads the centroid position signals of the beam output by the first and second detection units through a central controller, and outputs driving signals to drive the first and second correction execution units to perform micro-angle deflection on the X and Y axes, thereby compensating for beam pointing deviation in real time and forming a fully closed-loop control loop. This continuously corrects slow drift and maintains long-term stability of the beam pointing. The laser scanning processing system, by setting the central controller's control timing to coordinate with the laser emission control and galvanometer scanning actions, ensures that the stable closed-loop loop can operate continuously during the processing of intermittent laser emission and dynamic galvanometer scanning. The correction action and scanning action are decoupled, ensuring stable beam pointing accuracy throughout the entire dynamic processing process and possessing excellent long-term anti-drift capability, effectively improving processing accuracy and product yield. Attached Figure Description
[0023] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but should not be construed as limiting the invention. In the drawings, Figure 1 : A schematic diagram of the laser pointing stabilization control system of the present invention; Figure 2 The laser pointing stabilization control system of this invention is shown in the curves comparing the long-term drift of the beam centroid position in the controlled state and the uncontrolled state. Figure 3 : A schematic diagram of the structure of the laser scanning processing system of the present invention; Figure 4 Comparison of processing morphology and linewidth of the laser scanning processing system of the present invention in controlled and uncontrolled states; Figure 5 : Flowchart of the laser pointing stabilization control method of the present invention.
[0024] Names and numbers of each component Central controller 1; laser 2; beam expander 3; first reflector 4; first correction execution unit 5; second reflector 6; second correction execution unit 7; third reflector 8; fourth reflector 9; beam terminator 10; first detection unit 11; second detection unit 12; spot analyzer 13; plano-convex lens 14; galvanometer 15; field lens 16; sample 17. Detailed Implementation
[0025] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.
[0026] like Figure 1 and Figure 2 As shown, the laser pointing stabilization control system of the present invention includes a central controller 1, a laser 2, a beam expander 3, a first reflector 4, a first correction execution unit 5, a second reflector 6, a second correction execution unit 7, a third reflector 8, a fourth reflector 9 and a beam terminator 10 arranged sequentially along the beam transmission direction.
[0027] The second correction execution unit 7 has a first detection unit 11 on its light-transmitting side, and a portion of the light beam passing through the second correction execution unit 7 will be incident on the first detection unit 11; the third reflector 8 has a second detection unit 12 on its light-transmitting side, and a portion of the light beam passing through the third reflector 8 will be incident on the second detection unit 12.
[0028] Laser 2 is used to output high-quality pulsed laser. Beam expander 3 is used to expand, collimate, and control the divergence angle of the beam output from laser 2.
[0029] The first reflector 4 and the second reflector 6 are both used to adjust the transmission direction of the beam and provide fine-tuning dimension so that the laser beam is accurately incident on the first correction execution unit 5 and the second correction execution unit 7, respectively.
[0030] In this embodiment, both the first detection unit 11 and the second detection unit 12 are spot centroid detectors, and both the first detection unit 11 and the second detection unit 12 are used to collect the centroid position signal of the light beam and transmit the data to the central controller 1 in real time.
[0031] In another preferred embodiment, the first detection unit 11 and the second detection unit 12 may be replaced with a position-sensitive detector (PSD) to improve response speed and adapt to higher dynamic correction scenarios, but this is not a limitation.
[0032] In this embodiment, the first correction execution unit 5 and the second correction execution unit 7 are both electrically controlled reflectors, used to compensate for the pointing deviation of the beam in real time based on the centroid position signal of the beam collected by the first detection unit 11 and the second detection unit 12, respectively.
[0033] In another preferred embodiment, the first correction execution unit 5 and the second correction execution unit 7 can be replaced with a piezoelectric driven fast steering mirror (FSM) to further improve the correction bandwidth and response frequency, but this is not a limitation.
[0034] Both the third reflecting mirror 8 and the fourth reflecting mirror 9 are used to adjust the transmission direction of the beam and provide fine-tuning dimensions. Furthermore, a beam analyzer 13 is provided on the light-transmitting side of the fourth reflecting mirror 9 as an auxiliary measurement device for debugging and verification, to visually monitor the actual beam drift and compare and verify the correction effect.
[0035] The third reflector 8 ensures that the light beam is precisely incident on the fourth reflector 9, and part of the light beam passes through the third reflector 8 and is incident on the second detection unit 12; the fourth reflector 9 ensures that the light beam is precisely incident on the beam terminator 10, and part of the light beam passes through the fourth reflector 9 and is incident on the spot analyzer 13.
[0036] In addition, plano-convex lenses 14 are provided between the second correction execution unit 7 and the first detection unit 11, between the third reflector 8 and the second detection unit 12, and between the fourth reflector 9 and the spot analyzer 13.
[0037] The central controller 1 is electrically connected to the laser 2, the first calibration execution unit 5, the second calibration execution unit 7, the first detection unit 11, the second detection unit 12, and the spot analyzer 13, and is used to coordinate the timing and parameters of each module.
[0038] The working principle of the laser pointing stabilization control system of the present invention is as follows: First, the beam emitted by laser 2 is expanded and collimated by beam expander 3 and then enters first reflector 4. The beam is reflected by first reflector 4 to first correction execution unit 5, and then reflected by first correction execution unit 5 to second reflector 6. Then, the beam is reflected by the second reflector 6 to the second correction execution unit 7, and then reflected by the second correction execution unit 7 to the third reflector 8. At the same time, part of the beam passes through the second correction execution unit 7 and enters the first detection unit 11. The beam is reflected by the third emission mirror and enters the fourth reflector 9. At the same time, part of the beam passes through the third reflector 8 and enters the second detection unit 12. When the beam enters the first detection unit 11 and the second detection unit 12, the first detection unit 11 and the second detection unit 12 respectively collect the centroid position signal of the beam, and calculate the position deviation and angle deviation of the beam respectively, thus fully characterizing the two-dimensional deviation of the beam direction; then, the central controller 1 drives the first correction execution unit 5 and the second correction execution unit 7 to adjust in coordination based on the position + angle two-dimensional deviation, so as to realize the full parameter correction of the beam direction deviation. Finally, the beam is reflected by the fourth reflecting mirror 9 and enters the beam terminator 10, where it is terminated. Simultaneously, a portion of the beam passes through the fourth reflecting mirror 9 and enters the beam spot analyzer 13. The beam spot analyzer 13 is used to visually monitor the actual beam drift and verify the correction effect. Please refer to [link / reference] for details. Figure 2 , Figure 2 The graph shows a comparison of the long-term drift of the beam centroid position under controlled and uncontrolled conditions. After more than 100 hours of continuous locked operation testing, the RMS (Root Mean Square) deviation of the beam centroid in the X direction was as low as 0.84 μm, and the RMS deviation in the Y direction was as low as 1.99 μm. Compared with the uncontrolled and stable natural drift state, the optimization rate of RMS in the X direction reached 82.39%, the optimization rate of extreme value deviation reached 72.61%, the optimization rate of RMS in the Y direction reached 63.22%, and the optimization rate of extreme value deviation reached 61.38%. The optimization range of all indicators exceeded 60%, demonstrating excellent long-term anti-drift capability.
[0039] like Figure 3 and Figure 4 As shown, the laser scanning processing system of the present invention includes a motion platform and the aforementioned laser pointing stabilization control system, wherein the aforementioned laser pointing stabilization control system replaces the beam terminator 10 with a galvanometer 15 and a field mirror 16; wherein the galvanometer 15 is electrically connected to the central controller 1, and a sample 17 is placed on the motion platform.
[0040] Specifically, the laser scanning processing system is laid out as follows: along the laser incident transmission direction, the first correction execution unit 5 and the second correction execution unit 7 are arranged in front as execution elements for beam pointing correction, and then connected in sequence to the galvanometer 15 and the field mirror 16, forming the scanning processing optical path.
[0041] By placing the first detection unit 11 and the second detection unit 12 at specific positions in the optical path to acquire the centroid position signal of the output beam and transmit the data to the central controller 1 in real time, it is effectively ensured that the correction action acts on the front end of the scanning processing optical path, and the correction effect can be completely transmitted to the processing surface of the sample 17, avoiding interference of the scanning action with the stabilization circuit. Please refer to [link / reference] for details. Figure 4 , Figure 4The comparison of the processing morphology and linewidth of the laser scanning processing system under controlled and uncontrolled conditions is shown. Under controlled conditions, there are no morphological defects such as tailing or burrs on the surface of the processed area. During the non-continuous laser operation, the first correction execution unit 5 and the second correction execution unit 7 show no positional rebound or drift. The consistency of the processing linewidth is significantly improved, with the linewidth narrowing by 5.8μm at 30% laser power and by 25.27μm at 90% high power. The high-power thermal drift suppression effect is outstanding, which can effectively improve processing accuracy and product yield.
[0042] This specific position is the incident front end of the scanning processing optical path (i.e., galvanometer 15 + field mirror 16), and the design of this specific position has the following two core functions: (1) Optical magnification offset: By correcting the preceding optical path between the first correction execution unit 5 and the first detection unit 11, and between the second correction execution unit 7 and the second detection unit 12, the small pointing offset of the beam is optically magnified, thereby improving the recognition accuracy of the first detection unit 11 and the second detection unit 12 for the small beam offset and ensuring the sensitivity of the closed-loop correction. (2) Source monitoring and correction: Located at the front end of the scanning processing optical path, it can completely monitor the state of all beams in the incident scanning processing optical path and correct the beam pointing deviation from the source to maximize the stability of the beam at the processing end.
[0043] In another preferred embodiment, the first correction execution unit 5 and the second correction execution unit 7 can be arranged rearward between the scanning optical path and the processing surface of the sample 17 to adapt to the equipment modification requirements of special optical path layout.
[0044] like Figure 5 As shown, the present invention also provides a laser pointing stabilization control method, comprising the following steps: S1: The central controller 1 issues a command to start the laser 2 to emit a beam. The beam travels along the optical path and is reflected by the second reflector 6 to the second correction execution unit 7. The second correction execution unit 7 then reflects the beam to the third reflector 8. At the same time, part of the beam passes through the second correction execution unit 7 and is incident on the first detection unit 11, where the first detection unit 11 collects the X-axis and Y-axis position data of the beam. The beam is then reflected by the third reflector 8 and enters the fourth reflector 9. At the same time, part of the beam passes through the third reflector 8 and is incident on the second detection unit 12, where the second detection unit 12 collects the X-axis and Y-axis position data of the beam. S2: The central controller 1 reads the X-axis and Y-axis position data of the beam collected by the first detection unit 11 and the second detection unit 12 at a fixed sampling frequency, compares it with the preset reference position to calculate the deviation, and after digital filtering and closed-loop control algorithm calculation, outputs the drive signal to the first correction execution unit 5 and the second correction execution unit 7 to drive the first correction execution unit 5 and the second correction execution unit 7 to perform micro-angle deflection of the X-axis and Y-axis, and to compensate for the beam pointing deviation in real time, forming a full closed-loop control loop. It continuously corrects the slow drift caused by environmental temperature change, mechanical creep, etc., and maintains the long-term stability of the beam pointing. Compared with the natural drift state without stabilization control, the beam centroid RMS deviation in the X-axis and the RMS deviation in the Y-axis have excellent long-term anti-drift capability.
[0045] In this step, the reference position is set through two steps: optical design and calibration, as detailed below: ①Optical design positioning: Based on the target offset magnification, calculate the optical path lengths from the first correction execution unit 5 to the first detection unit 11 and from the second correction execution unit 7 to the second detection unit 12 respectively, and determine the installation reference positions of the first detection unit 11 and the second detection unit 12 at the incident front end of the scanning processing optical path along the beam transmission direction. ② Calibration and verification: After the first detection unit 11 and the second detection unit 12 are installed, a reference beam with a known deflection is input to the first detection unit and the second detection unit. The correspondence between the offset output by the first detection unit 11 and the second detection unit 12 and the actual offset of the processing surface of the sample 17 is calibrated. After confirming that the detection accuracy meets the requirements, the position setting is completed.
[0046] In this step, the closed-loop control algorithm includes three core components: moving average digital filtering calculation, coupled calculation of position and angle deviation by the first detection unit 11 and the second detection unit 12, and PI closed-loop control calculation, as detailed below: 1. Moving average digital filtering operation (suppressing random noise in the probe) The raw sampling data from the first detection unit 11 and the second detection unit 12 are subjected to moving average filtering. The filtered position data from both sources remove random noise from the detection and improve the accuracy of the deviation calculation. The details are as follows: Coordinates of the first detection unit 11 after filtering:
[0047] Coordinates after filtering by the second detection unit 12:
[0048] Where, x 1，i y 1，iThese are the original centroid coordinates along the X and Y axes of the first detection unit 11 during the i-th sampling; x 2，i y 2，i These are the original centroid coordinates along the X and Y axes of the second detection unit 12 during the i-th sampling; x 1，k , 1，k x represents the centroid coordinates of the first detection unit 11 after the k-th filtering. 2，k , 2，k is the centroid coordinate of the second detection unit 12 after the kth filtering; N is the number of sampling points of the sliding window.
[0049] 2. The first detection unit 11 and the second detection unit 12 are coupled to calculate the position and angle deviation. By utilizing the spacing between the first detection unit 11 and the second detection unit 12 along the optical axis, and through the coupled calculation of the two filtered position data, the position deviation and angular deviation of the beam are obtained respectively, thus realizing a complete characterization of the two-dimensional deviation of the beam pointing, as detailed below: Positional deviation:
[0050] Angle deviation:
[0051] Where Δx and Δy are the X-axis and Y-axis position deviations of the light beam at the first detection unit 11; θ x θ y L represents the angular deviation of the light beam in the X and Y axis directions; L represents the distance between the first detection unit 11 and the second detection unit 12 along the optical axis.
[0052] 3. PI (Proportional-Integral) Closed-Loop Control Calculation (output to the first correction execution unit 5 and the second correction execution unit 7) PI control calculations are performed on the calculated position and angle deviations, outputting two independent control signals to drive the first correction execution unit 5 and the second correction execution unit 7 respectively. This collaboratively completes the real-time correction of beam position and angle drift, forming a fully closed-loop control circuit. Since the Y-axis control logic is completely consistent with the X-axis logic, the following explanation uses the X-axis as an example: (a) Deviation calculation:
[0053] (b) Control output:
[0054] Where, x e y e The preset beam reference position coordinates; θ x， e θ y， e The preset beam reference angle; e x (k), e y (k) represents the positional deviation along the X and Y axes at time k; e_θ x (k), e_θ y (k) represents the angular deviation in the X-axis and Y-axis directions at time k; K p1 K i1 These are the proportional and integral coefficients of the position correction loop, respectively; K p2 K i2 These are the proportional coefficient and integral coefficient of the angle correction loop, respectively; u1(k) is the drive control quantity output to the first correction execution unit 5 (corresponding to position correction); u2(k) is the drive control quantity output to the second correction execution unit 7 (corresponding to angle correction).
[0055] S3: The beam, after being corrected by closed-loop control, is incident on the galvanometer 15. After high-speed scanning by the galvanometer 15, it is finally focused onto the surface of the sample 17 by the field lens 16 to process the sample 17.
[0056] In this step, the surface of the processed area of sample 17 is free of morphological defects such as tailing and burrs. During the non-continuous laser operation phase, the first correction execution unit 5 and the second correction execution unit 7 have no position rebound or drift. The consistency of the processing linewidth is significantly improved, and the high-power thermal drift suppression effect is outstanding, effectively improving the processing accuracy and product yield.
[0057] In summary, the laser pointing stabilization control system, scanning processing system, and control method of the present invention have the following advantages: 1. The laser pointing stabilization control system reads the centroid position signal of the beam output by the first detection unit 11 and the second detection unit 12 by setting the central controller 1, compares it with the preset reference position to calculate the deviation, and after digital filtering and closed-loop control algorithm calculation, outputs a drive signal to drive the first correction execution unit 5 and the second correction execution unit 7 to perform dual-axis micro-angle deflection, and performs real-time compensation for beam pointing deviation, forming a full closed-loop control loop to continuously correct slow drift and maintain long-term stability of beam pointing.
[0058] 2. The laser scanning processing system uses a central controller 1 to control the timing and coordinate the light output control of the laser 2 and the scanning action of the galvanometer 15. During the processing of intermittent light output from the laser 2 and dynamic scanning by the galvanometer 15, the stable closed-loop circuit can work continuously. The correction action and the scanning action are not coupled (i.e., decoupled), which effectively ensures the stability of the beam pointing accuracy throughout the entire dynamic processing process and has excellent long-term anti-drift capability, effectively improving processing accuracy and product yield.
[0059] Any combination of various embodiments of the present invention, provided it does not violate the inventive concept of the present invention, shall be regarded as the content disclosed by the present invention; within the scope of the technical concept of the present invention, any simple modifications to the technical solution and any combination of different embodiments that do not violate the inventive concept of the present invention shall be within the protection scope of the present invention.
Claims
1. A laser pointing and stabilizing control system, characterized in that, include: The system comprises a central controller, a laser, a beam expander, a first reflector, a first correction execution unit, a second reflector, a third reflector, and a fourth reflector, arranged sequentially along the beam transmission direction. The laser is used to output high-quality pulsed laser; the beam expander is used to expand, collimate, and control the divergence angle of the beam output by the laser; the first reflector, the second reflector, the third reflector, and the fourth reflector are all used to adjust the transmission direction of the beam; A first detection unit is provided on the light-transmitting side of the second correction execution unit, and a second detection unit is provided on the light-transmitting side of the third reflector; a portion of the light beam passing through the second correction execution unit is incident on the first detection unit, and a portion of the light beam passing through the third reflector is incident on the second detection unit; The first correction execution unit and the second correction execution unit are used to compensate for the pointing offset of the beam in real time based on the centroid position signal of the beam collected by the first detection unit and the second detection unit, respectively. The central controller is electrically connected to the laser, the first correction execution unit, the second correction execution unit, the first detection unit, and the second detection unit.
2. The laser pointing stabilization control system as described in claim 1, characterized in that: A beam analyzer is installed on the light-transmitting side of the fourth reflector. The beam analyzer is electrically connected to the central controller and is used to monitor the actual beam drift.
3. The laser pointing stabilization control system as described in claim 1, characterized in that: Both the first correction execution unit and the second correction execution unit are electrically controlled reflectors or piezoelectrically driven fast deflectors; both the first detection unit and the second detection unit are spot centroid detectors or position-sensitive detectors.
4. A laser scanning processing system, characterized in that, include: The laser pointing and stabilizing control system as described in any one of claims 1 to 3, and the galvanometer and the field mirror sequentially arranged after the laser pointing and stabilizing control system along the beam transmission direction, wherein the galvanometer and the field mirror constitute a scanning processing optical path; The galvanometer is used to achieve high-speed scanning within the processing area of the field lens; and the galvanometer is electrically connected to the central controller; the field lens is used to focus the light beam onto the surface of the sample.
5. A laser pointing stabilization control method, characterized in that, Using the laser scanning processing system described in claim 4, Includes the following steps: S1: The central controller issues a command to start the laser and emit a beam. The beam travels along the optical path and is reflected by the second reflector to the second correction execution unit. The second correction execution unit then reflects the beam to the third reflector. At the same time, part of the beam passes through the second correction execution unit and is incident on the first detection unit, which collects the X-axis and Y-axis position data of the beam. The beam is then reflected by the third reflector and enters the fourth reflector. At the same time, part of the beam passes through the third reflector and is incident on the second detection unit, which collects the X-axis and Y-axis position data of the beam. S2: The central controller reads the X-axis and Y-axis position data of the beam collected by the first and second detection units at a fixed sampling frequency, compares it with the preset reference position to calculate the deviation, and after digital filtering and closed-loop control algorithm calculation, outputs a drive signal to the first and second correction execution units to drive the first and second correction execution units to perform micro-angle deflection on the X-axis and Y-axis, to compensate for the beam pointing deviation in real time, form a full closed-loop control loop, and continuously correct the slow drift.
6. The laser pointing stabilization control method as described in claim 5, characterized in that: In step S2, the reference position is set through two steps: optical design and calibration verification. First, optical design and positioning are performed: based on the target offset magnification, the optical path lengths from the first correction execution unit to the first detection unit and from the second correction execution unit to the second detection unit are calculated respectively. Along the beam transmission direction, at the incident front end of the scanning processing optical path, the mounting reference positions of the first and second detection units are determined. Then, calibration and verification are performed: After the first and second detection units are installed, a reference beam with a known deflection is input into the first and second detection units to calibrate the correspondence between the offset output by the first and second detection units and the actual offset of the sample's processing surface. After confirming that the detection accuracy meets the requirements, the position setting is completed.
7. The laser pointing stabilization control method as described in claim 5, characterized in that: In step S2, the closed-loop control algorithm includes moving average digital filtering calculation, coupled calculation of position and angle deviation by the first and second detection units, and PI closed-loop control algorithm.
8. The laser pointing stabilization control method as described in claim 7, characterized in that: The moving average digital filtering operation is as follows: The original sampling data from the first and second detection units are respectively subjected to moving average filtering to form two filtered position data streams; wherein, the filtered coordinates of the first detection unit are: Coordinates after filtering by the second detection unit: In the formula, x 1，i y 1，i These are the original centroid coordinates along the X and Y axes of the first detection unit during the i-th sampling; x 2，i y 2，i These are the original centroid coordinates along the X and Y axes of the second detection unit during the i-th sampling; x 1，k , 1，k x represents the centroid coordinates of the first detection unit after the k-th filtering. 2，k , 2，k is the centroid coordinate of the second detection unit after the k-th filtering; N is the number of sampling points in the sliding window.
9. The laser pointing stabilization control method as described in claim 8, characterized in that: The coupled calculation of position and angle deviations by the first and second detection units is as follows: using the distance between the first and second detection units along the optical axis, the position and angle deviations of the beam are obtained by coupled calculation of the two filtered position data. Positional deviation: Angular deviation: In the formula, Δx and Δy are the X-axis and Y-axis position deviations of the light beam at the first detection unit; θ x θ y L represents the angular deviation of the beam in the X and Y axes; L is the distance between the first and second detection units along the optical axis.
10. The laser pointing stabilization control method as described in claim 9, characterized in that: The PI closed-loop control algorithm is as follows: PI control calculations are performed on the calculated position and angle deviations, outputting two independent control quantities to drive the first and second correction execution units respectively, collaboratively completing the real-time correction of beam position and angle drift, forming a full closed-loop control circuit. The Y-axis control logic is consistent with the X-axis logic, including: (a) Deviation calculation: (b) Control output: In the formula, x e y e The preset beam reference position coordinates; θ x， e θ y， e The preset beam reference angle; e x (k), e y (k) represents the positional deviation along the X and Y axes at time k; e_θ x (k), e_θ y (k) represents the angular deviation in the X-axis and Y-axis directions at time k; K p1 K i1 These are the proportional and integral coefficients of the position correction loop, respectively; K p2 K i2 These are the proportional coefficient and integral coefficient of the angle correction loop, respectively; u1(k) is the drive control quantity output to the first correction execution unit; u2(k) is the drive control quantity output to the second correction execution unit.