A device and method for online correction of beam pointing jitter for laser processing

Abstract

The present invention discloses an online correction device and method for beam pointing jitter for laser processing, which solves the problem that the laser pointing correction method cannot detect and correct the high-frequency and low-frequency angle and translation errors of the beam respectively. Specifically, it includes a translation component detection and correction unit and an angle component detection and correction unit arranged in sequence along the incident light, and a control unit; the translation component detection and correction unit includes a first reflector, a first drive assembly, a first spectroscope and a first detection assembly; the angle component detection and correction unit includes a second reflector, a second drive assembly, a second spectroscope, an optical path extension assembly and a second detection assembly; the control unit is used to control the first drive assembly to adjust the posture of the first reflector and / or control the second drive assembly to adjust the posture of the second reflector according to the first detection information of the first detection assembly and the second detection information of the second detection assembly, so as to correct the fourth reflected light.

Description

Technical Field

[0001] The present invention relates to a device and method for correcting light beam pointing, and in particular to a device and method for online correction of light beam pointing jitter for laser processing. Background Art

[0002] Beam pointing stabilization control technology is widely used in laser communications, laser manufacturing, and other aspects. In laser processing equipment, during the actual transmission of the light beam, the thermal effect of the laser, the thermal gradient of cooling, mechanical vibration, and the thermal strain, mechanical vibration, spatial displacement, and thermal turbulence of the air in the optical system during the propagation of the light beam will cause the laser beam to produce angular drift, jitter and other unstable phenomena during the propagation of the air, which will directly reduce the position accuracy and dimensional accuracy of the laser processing. Therefore, in the process of ultrafast laser precision processing, beam pointing stabilization control is particularly important.

[0003] During this laser processing process, laser beam jitter and offset are near-field beam errors, and both translational and angular offsets are significant. Therefore, it is necessary to comprehensively consider both angular and translational corrections, placing stringent demands on signal processing and correction algorithms. Therefore, it is crucial to reduce the complexity of signal processing and jitter correction algorithms, and to improve the accuracy and speed of pointing corrections for laser processing pointing errors.

[0004] Common laser pointing correction methods include optomechanical correction technology, optical phased array technology (OPA) and metasurface phase control technology.

[0005] Optical-mechanical correction technology is mainly based on mechanically rotating the direction of the reflector to achieve control of the direction of the reflected laser. Its basic principle is to use CCD, CMOS, PSD and other imaging methods to detect the position of the light beam, and then drive the reflector through motion mechanisms such as stepper motors, piezoelectric ceramics, and MEMS scanning mirrors to correct the direction of the light beam. This technology is a relatively mature and widely used technology in the current light beam stability control technology, but it is limited to the existing design principle scheme and cannot detect and correct the high-frequency and low-frequency drift, angle and translation errors of the light beam respectively, resulting in its poor adaptability in the field of laser manufacturing.

[0006] Phased array correction technology (OPA) achieves microwave direction control by independently controlling the phase delay of each microwave antenna. The same principle can be directly applied to the optical band. At present, OPA mainly uses liquid crystal, optical waveguide and MEMS technologies to control the phase. Among them, liquid crystal phased array technology uses external voltage to change the refractive index of liquid crystal molecules to achieve phase control. Its discrete pressurization method leads to the existence of diffraction effects, which affects the control range and accuracy of the light beam direction. This limitation also exists in waveguide phased array technology. In addition, liquid crystal phased array technology is relatively mature. Although it has certain practical value, the liquid crystal movement speed is slow and difficult to integrate. Optical waveguide technology utilizes electro-optical and thermo-optical properties of materials (such as lithium niobate and lithium tantalate) and silicon (such as silicon) to provide large beam steering angles. For example, an MIT research group has achieved a one-dimensional silicon-based waveguide optical phased array with a device size of 1200μm × 200μm. At a heating power of 1.2W, the beam can be deflected up to 46° × 36° with a beam width of 0.85° × 0.18° when the wavelength is tuned from 1454nm to 1641nm. MEMS phased array technology uses mechanical means to control the phase of each element, offering fast scanning speeds and low energy consumption. However, the deflection angle is limited (approximately 2°). Achieving large-angle, high-precision beam steering requires high requirements for both the magnitude and accuracy of the optical phase delay. Existing OPA technology is limited by array element size, phase errors caused by structural manufacturing errors, and device manufacturing size (edge ​​diffraction occurs at small sizes and processing uniformity is reduced at large sizes). Consequently, it can only achieve discrete phase control, making it difficult to achieve continuous deflection correction of the laser beam's direction.

[0007] Metasurface phase control technology uses subwavelength units to produce 360° phase changes, and combines other optically adjustable materials (such as liquid crystals, phase change materials, semiconductor materials, etc.) to achieve controllable phase changes, thereby controlling the direction of laser transmission. By designing different structures, different control effects can be produced for different polarized light, and functions such as focusing and deflection can also be integrated into a metasurface structure to achieve a higher degree of device integration. However, the existing metasurface processing technology is immature, and the processing accuracy and width of subwavelength-level micro-nano structures are extremely limited, which restricts the application of metasurface phase control technology, that is, it is impossible to accurately control the transmission direction of the laser beam. Summary of the Invention

[0008] The purpose of the present invention is to provide an online correction device and method for beam pointing jitter for laser processing, so as to solve the technical problems that the laser pointing correction method cannot detect and correct the angle and translation errors of the beam separately, and it is difficult to achieve continuous deflection correction of the laser beam pointing.

[0009] To achieve the above-mentioned object, the present invention provides an online correction device for beam pointing jitter for laser processing, which is special in that it includes a translation component detection and correction unit and an angle component detection and correction unit sequentially arranged along the incident light, and a control unit;

[0010] The translation component detection and correction unit includes a first reflector, a first drive assembly, a first spectroscope, and a first detection assembly; the first reflector is mounted on an active end of the first drive assembly, and is configured to reflect incident light to form a first reflected light; the first drive assembly is configured to adjust the position and angle of the first reflector; the first spectroscope splits the first reflected light into a second reflected light and a first transmitted light; the first detection assembly is disposed in an optical path of the second reflected light, and is configured to receive the second reflected light;

[0011] The angle component detection and correction unit includes a second reflector, a second drive assembly, a second beam splitter, an optical path extension assembly, and a second detection assembly; the second reflector is mounted on the active end of the second drive assembly, and is used to reflect the first transmitted light to form a third reflected light; the second drive assembly is used to adjust the position and angle of the second reflector; the second beam splitter splits the third reflected light into a fourth reflected light and a second transmitted light; the fourth reflected light is used for laser processing; the optical path extension assembly and the second detection assembly are sequentially arranged along the optical path of the second transmitted light, and the optical path extension assembly extends the second transmitted light to expand the linear value of its angular error; the second detection assembly is used to receive the second transmitted light after the linear value of the angular error has been expanded;

[0012] The control unit is respectively connected to the first drive component, the first detection component, the second drive component and the second detection component, and is used to control the first drive component to adjust the posture of the first reflector and / or control the second drive component to adjust the posture of the second reflector according to the first detection information of the first detection component and the second detection information of the second detection component to correct the fourth reflected light.

[0013] Furthermore, the optical path extension assembly includes a third reflector, a fourth reflector and a fifth reflector; the fourth reflector is parallel to the fifth reflector;

[0014] The third reflector is arranged on the optical path of the second transmitted light, and is used to reflect the second transmitted light to the surface of the fourth reflector, and perform multiple reflections between the fifth reflector and the fourth reflector;

[0015] The second detection component is arranged on the optical path of the second transmitted light after multiple reflections.

[0016] Furthermore, the optical path extension assembly further includes a long zoom objective lens;

[0017] The long zoom objective lens is arranged between the second beam splitter and the third reflector and is located on the optical path of the second transmitted light, and is used for focusing the second transmitted light.

[0018] Furthermore, the fifth reflector is a telephoto cylindrical reflector.

[0019] Furthermore, the first detection assembly includes a third spectroscope, a CCD and a PSD;

[0020] The third beam splitter is arranged on the optical path of the second reflected light, and is used to split the second reflected light into a fifth reflected light and a third transmitted light;

[0021] The CCD is arranged on the optical path of the fifth reflected light and is connected to the control unit, and is used to receive the fifth reflected light;

[0022] The PSD is disposed on the optical path of the third transmitted light and is connected to the control unit for receiving the third transmitted light.

[0023] Furthermore, the second detection assembly includes a fourth beam splitter, a CCD and a PSD;

[0024] The fourth beam splitter is arranged on the second transmitted light, and is used to split the second transmitted light into a sixth reflected light or a fourth transmitted light;

[0025] The CCD is arranged on the sixth reflected light and is connected to the control unit, and is used to receive the sixth reflected light;

[0026] The PSD is disposed on the fourth transmitted light and is connected to the control unit for receiving the fourth transmitted light.

[0027] Furthermore, the splitting ratio of the first beam splitter is 9:1, wherein the second reflected light accounts for 10% and the first transmitted light accounts for 90%;

[0028] The splitting ratio of the second beam splitter is 1:9, wherein the fourth reflected light accounts for 90% and the second transmitted light accounts for 10%;

[0029] The splitting ratio between the third beam splitter and the fourth beam splitter is 1:1.

[0030] Furthermore, the first driving component includes a first piezoelectric ceramic and a first driving motor;

[0031] The first piezoelectric ceramic is arranged on the back of the first reflector, and the output end of the first driving motor is connected to the first reflector through the first piezoelectric ceramic;

[0032] The second driving component includes a second piezoelectric ceramic and a second driving motor;

[0033] The second piezoelectric ceramic is arranged on the back of the second reflector, and the output end of the second driving motor is connected to the second reflector through the second piezoelectric ceramic.

[0034] Furthermore, the first drive motor and the second drive motor are both stepping motors.

[0035] At the same time, the present invention also provides a method for correcting laser beam pointing jitter for laser processing, which is based on the above-mentioned online correction device for laser beam pointing jitter, and is special in that it includes the following steps:

[0036] Step 1: The first detection component receives the second reflected light to obtain first detection information, and sends the first detection information to the control unit. At the same time, the second detection component receives the second transmitted light to obtain second detection information, and sends the second detection information to the control unit.

[0037] Step 2: The control unit determines whether the incident light has a translation error and / or an angle error based on the first detection information and the second detection information:

[0038] If it does not exist, return to step 1 and perform real-time monitoring;

[0039] If yes, calculate the angle error according to the second detection information, calculate the translation error according to the first detection information and the second detection information, and then execute step 3;

[0040] Step 3: The control unit controls the second drive assembly to adjust the posture of the second reflector according to the calculated angular error; and controls the first drive assembly to adjust the posture of the first reflector according to the calculated translation error.

[0041] Beneficial effects of the present invention:

[0042] 1) The present invention sequentially arranges a translation component detection and correction unit and an angle component detection and correction unit on the optical path where the incident light is located, and uses the difference between high frequency and low frequency to detect the translation component and the angle component respectively, thereby reducing the development difficulty of the existing light beam pointing jitter control correction, providing the possibility of realizing online correction, and also improving the efficiency of the control algorithm.

[0043] 2) The present invention introduces a long zoom objective lens in the angle component detection and correction unit to decompose the angle error and the translation error, and sets a first reflector and a first detection assembly to detect and correct the translation error, and a second reflector and a second detection assembly to detect the angle error, which further reduces the difficulty of decomposing and correcting the two errors and improves the practicability of online correction.

[0044] 3) The present invention corrects high-frequency and low-frequency errors separately, and uses a combined structure of piezoelectric ceramics with fast response speed but small motion range and a stepper motor with slow response speed but large motion range to drive the first reflector and the second reflector, so as to correct high-frequency, small-amplitude beam jitter and low-frequency, large-amplitude beam drift. It not only has the large-range characteristics of motor drive, but also integrates the characteristics of high speed and high resolution, which greatly improves the application range and service life of the two reflectors.

[0045] 4) The present invention incorporates a long zoom objective lens for focusing within the angular component detection and correction unit. This increases the linear value of the error on the target surface while maintaining a constant angular error, further improving detection resolution and accuracy. Furthermore, the variable focal length significantly increases the range of correctable angular errors, broadening the correctable error angle range.

[0046] 5) The laser processing light beam pointing jitter online correction device provided by the present invention can greatly improve the position and dimensional accuracy of laser processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 2. It is a schematic structural diagram of an embodiment of an online correction device for beam pointing jitter for laser processing according to the present invention;

[0048] Figure 2 is a diagram of the parallel offset component of the laser spot in an embodiment of the present invention;

[0049] Figure 3 is a graph of the laser spot angle offset component in an embodiment of the present invention;

[0050] Figure 4 is a calculation and analysis diagram of the laser offset in an embodiment of the present invention;

[0051] Figure 5 is a schematic diagram of the algorithm control principle within the control unit in an embodiment of the present invention;

[0052] Figure 6 This is a flow chart of a method for correcting beam pointing jitter for laser processing in an embodiment of the present invention.

[0053] Figure Number:

[0054] 1- translation component detection and correction unit, 11- first reflector, 12- first spectrometer, 13- first detection assembly, 131- third spectrometer, 132- CCD1, 133- PSD1;

[0055] 2-angle component detection and correction unit, 21-second reflector, 22-second beam splitter, 23-optical path extension assembly, 231-third reflector, 232-fourth reflector, 233-fifth reflector, 234-long zoom objective lens, 24-second detection assembly, 241-fourth beam splitter, 242-CCD2, 243-PSD2;

[0056] 01-incident light, 02-first reflected light, 03-second reflected light, 04-first transmitted light, 05-third reflected light, 06-fourth reflected light, 07-second transmitted light, 08-fifth reflected light, 09-third transmitted light, 010-sixth reflected light, 011-fourth transmitted light. DETAILED DESCRIPTION

[0057] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0058] The light beam pointing deviation can be divided into high-frequency jitter and low-frequency drift according to the frequency. Low-frequency drift has the characteristics of low frequency, large amplitude, and fixed direction, and the difficulty of online correction is controllable. High-frequency jitter has the characteristics of high frequency, small amplitude, and no directionality, and the difficulty of online correction is extremely great. Traditional pointing deviation correction methods and devices will not decompose the above deviations, resulting in the correction scheme and system being too complicated, and the subsequent correction algorithm development is difficult, making the final laser pointing correction accuracy uncontrollable and difficult to achieve online correction. In addition, the light beam pointing deviation, whether high frequency or low frequency, can be further decomposed into angle deviation components and translation components. Decomposing its deviation error is conducive to further simplifying the correction algorithm and improving its practicability of online correction. Based on this, the present invention proposes an online correction device for light beam pointing jitter for laser processing, such as Figure 1 As shown, the device includes a translation component detection and correction unit 1, an angle component detection and correction unit 2, and a control unit, which are sequentially arranged along the incident light ray 01;

[0059] The translation component detection and correction unit 1 includes a first reflector 11, a first drive assembly, a first spectrometer 12 and a first detection assembly 13; the first reflector 11 is installed at the active end of the first drive assembly, and is used to reflect the incident light 01 to form a first reflected light 02; specifically, the first drive assembly includes a first piezoelectric ceramic and a first drive motor; the first piezoelectric ceramic is arranged on the back of the first reflector 11, and the output end of the first drive motor is connected to the first reflector 11 through the first piezoelectric ceramic; the first piezoelectric ceramic is a PZT piezoelectric ceramic; the first drive motor is a stepper motor. The stepper motor and PZT piezoelectric ceramic jointly adjust the position and angle of the first reflector 11; the first spectrometer 12 divides the first reflected light 02 into the second reflected light 03 and the first transmitted light 04, and the splitting ratio of the first spectrometer 12 is 9:1, of which the second reflected light 03 accounts for 10% and the first transmitted light 04 accounts for 90%; the first detection component 13 is arranged on the optical path of the second reflected light 03, for receiving the second reflected light 03; specifically, the first detection component 13 includes a third spectrometer 131, a CCD1 132 and a PSD1 133; the third spectrometer 131 is arranged on the optical path of the second reflected light 03, for dividing the second reflected light 03 into a fifth reflected light 08 and a third transmitted light 09, and the splitting ratio of the third spectrometer 131 is 1:1; the CCD1 132 is arranged on the optical path of the fifth reflected light 08, and is connected to the control unit, for receiving the fifth reflected light 08; the PSD1 133 is arranged on the optical path of the third transmitted light 09, and is connected to the control unit, for receiving the third transmitted light 09.

[0060] The angle component detection and correction unit 2 includes a second reflector 21, a second drive assembly, a second beam splitter 22, an optical path extension assembly 23, and a second detection assembly 24. The second reflector 21 is mounted on the active end of the second drive assembly and is used to reflect the first transmitted light 04 to form the third reflected light 05. The second drive assembly is used to adjust the position and angle of the second reflector 21. Specifically, the second drive assembly includes a second piezoelectric ceramic and a second drive motor. The second piezoelectric ceramic is mounted on the back of the second reflector 21, and the output end of the second drive motor is connected to the second reflector 21 through the second piezoelectric ceramic. The second piezoelectric ceramic is a PZT piezoelectric ceramic; the second drive motor is a stepper motor. The second piezoelectric ceramic and the second drive motor work together to adjust the position and angle of the second reflector 21; the second spectrometer 22 divides the third reflected light 05 into the fourth reflected light 06 and the second transmitted light 07, and the splitting ratio of the second spectrometer 22 is 1:9, of which the fourth reflected light 06 accounts for 90% and the second transmitted light 07 accounts for 10%; the fourth reflected light 06 is used for laser processing; the optical path extension component 23 and the second detection component 24 are sequentially arranged along the second transmitted light 07, and the optical path extension component 23 extends the second transmitted light 07 to expand it The linear value of the angle error; specifically, the optical path extension component 23 includes a third reflector 231, a fourth reflector 232, a fifth reflector 233 and a long zoom objective lens 234; the fourth reflector 232 is parallel to the fifth reflector 233; the third reflector 231 is arranged on the optical path of the second transmitted light 07, and is used to reflect the second transmitted light 07 to the surface of the fourth reflector 232, and perform multiple reflections between the fifth reflector 233 and the fourth reflector 232; the second detection component 24 is arranged on the optical path of the second transmitted light 07 after multiple reflections. The long zoom objective lens 234 is arranged between the second beam splitter 22 and the third reflector 231, and is located on the optical path of the second transmitted light 07, and is used to focus the second transmitted light 07. In addition, the long zoom objective lens 234 can increase the correctable angular error within a very large range by adjusting the focal length. For example, during the detection process, the focal length can be adjusted to adjust the detection position of the light beam jitter on the CCD target surface, or when the light beam jitter exceeds the CCD detection target surface, it is adjusted to a smaller focal length so that the light beam can be successfully detected. The focal length is adjustable between 500mm and 1m, and there are two adjustment methods: when the long zoom objective lens 234 is placed, the fifth reflector 233 is a large-aperture plane reflector for compressing the optical path structure; when the long zoom objective lens 234 is cancelled, the fifth reflector 233 is a cylindrical long-focus reflector, which can compress the optical path while focusing.

[0061] The fifth reflector 233 is preferably a telephoto cylindrical reflector. The second detection assembly 24 is used to receive the second transmitted light 07 after the linear value of the angular error is expanded. Specifically, the second detection assembly 24 includes a fourth beam splitter 241, a CCD2 242, and a PSD2 243. The fourth beam splitter 241 is disposed on the optical path of the second transmitted light 07 and is used to split the second transmitted light 07 into a sixth reflected light 010 and a fourth transmitted light 011, with a splitting ratio of 1:1. The CCD2 242 is disposed on the optical path of the sixth reflected light 010 and is connected to the control unit for receiving the sixth reflected light 010. The PSD2 243 is disposed on the optical path of the fourth transmitted light 011 and is connected to the control unit for receiving the fourth transmitted light 011.

[0062] The control unit is respectively connected to the first driving component, the first detection component 13, the second driving component and the second detection component 24, and is used to control the first driving component to adjust the posture of the first reflector 11 and / or control the second driving component to adjust the posture of the second reflector 21 according to the first detection information of the first detection component 13 and the second detection information of the second detection component 24, so as to correct the fourth reflected light 06.

[0063] The incident laser beam passes through the first reflector 11 and the second reflector 21, with a first beam splitter 12 with a 90:10 splitting ratio placed between them. 10% of the light energy further passes through the third beam splitter 131 (with a 1:1 splitting ratio) and is incident on the CCD 1132 and PSD 133, respectively. The laser beam reflected by the second reflector 21 is then split into two beams by the second beam splitter 22 with a 90:10 splitting ratio. The 90% beam is directly output as the processing laser beam, while the remaining 10% undergoes multiple reflections between the telephoto cylindrical reflector and the fourth reflector 232, further increasing the optical path of the beam and maximizing the decoupling of the beam's translational and angular amounts. The beam then continues to be incident on the fourth beam splitter 241, where it undergoes a 1:1 splitting ratio and is incident on the CCD 242 and PSD 243, respectively.

[0064] The principles are as follows: 1) Separate detection of high-frequency and low-frequency errors: Pointing errors are detected using CCD and PSD, respectively. CCD, due to its large field of view and wide detection range, is used to correct low-frequency, large-scale pointing offset errors. PSD, due to its extremely high resolution, is used to correct high-frequency, small-scale pointing offset errors. 2) Separate correction of high-frequency and low-frequency errors: The first reflector 11 and the second reflector 21 simultaneously use a combination of stepper motors and piezoelectric ceramics to achieve attitude control. The stepper motor, due to its large adjustment range, is used to correct low-frequency, large-scale pointing offset errors detected by CCD. Piezoelectric ceramics, due to their high movement frequency and high precision but limited adjustment range, are used to correct high-frequency, small-scale pointing offset errors. 3) Separate detection and correction of angular error components and translation error components: Specifically, the first detection component 13 and the second detection component 24 are placed as far apart as possible, with the first detection component 13 placed behind the first reflector 11 and the second detection component 24 placed behind the second reflector 21. Secondly, a long zoom objective lens or a long focus cylindrical reflector (focal length ≥ 500mm) is used to focus the light beam, thereby achieving the translation and angular decomposition of the light beam deviation (the specific principle is as follows Figure 2 and Figure 3 As shown in FIG, a long zoom objective lens is used to maximize the range of light beam jitter detectable by the detector through zooming. The reason for using a long-focus cylindrical reflector is to maximize the linear value of the error and compress the optical path under the premise of consistent angular error, thereby improving the detection accuracy of the angular error. Finally, the translation error signal of the first detection component 13 is fed back to the first drive component of the first reflector 11 (including a stepper motor and piezoelectric ceramics), that is, the first reflector 11 is only used to correct the translation error. The angle error signal of the second detection component 24 is fed back to the second drive component of the second reflector 21, that is, the second reflector 21 is only used to correct the angle error.

[0065] The above-mentioned laser processing beam pointing jitter online correction device can be used to perform online laser correction, and the correction method includes the following steps:

[0066] Step 1: The first detection component 13 receives the second reflected light 03 to obtain first detection information, and sends the first detection information to the control unit. At the same time, the second detection component 24 receives the second transmitted light 07 to obtain second detection information, and sends the second detection information to the control unit.

[0067] Step 2: The control unit determines whether the incident light 01 has a translation error and / or an angle error based on the first detection information and the second detection information:

[0068] If it does not exist, return to step 1 and perform real-time monitoring;

[0069] If yes, calculate the angle error according to the second detection information, calculate the translation error according to the first detection information and the second detection information, and then execute step 3;

[0070] Step 3: The control unit controls the second drive assembly to adjust the posture of the second reflector 21 according to the calculated angular error; and controls the first drive assembly to adjust the posture of the first reflector 11 according to the calculated translation error. Specifically, the first detection information is fed back to the first reflector 11, and the second detection information is fed back to the second reflector 21.

[0071] like Figure 6 As shown, the control unit determines the process according to the first detection information and the second detection information as follows:

[0072] First, the error category is determined by comparing the motion amplitude and trajectory of the light spot on the PSD (including PSD1 and PSD2) and CCD (including CCD1 and CCD2) imaging target surfaces. If the PSD target surface measurement exceeds the width, and the CCD target surface measurement obtains a directional light spot offset with large fluctuations, it can be determined as a low-frequency error; if the light spot motion deviation range on the CCD target surface is less than one-tenth of its field of view, but the PSD can completely track the light spot motion trajectory, and the light beam has no directional rapid jitter within a certain range, it is a high-frequency error.

[0073] The beam deviation is then decomposed, and the determined low-frequency error or high-frequency error is further decomposed into translation error and / or angular error through the first detection information and the second detection information. If both the first detection components and the second detection components have light spot deviation, it proves that the error has both angular error and translation error. If the first detection component has light spot deviation and the second detection component has no light spot deviation, it proves that there is only translation error.

[0074] Then calculate the values ​​of translation error and angle error, such as Figure 4 As shown in the figure, the spot jitter △ of the first detection component is equal to the actual translation error of the light beam. If the angle error is △θ, the rotation angle of the second reflector is △θ′. The linear value of the spot jitter generated by the beam jitter angle on the CCD target surface is:

[0075] △=f×tan△θ

[0076] △θ′=△θ / 2

[0077] Wherein, f is the focal length of the telephoto cylindrical reflector or the focal length of the focusing objective lens, and Δθ′ is the rotation angle value of the second reflector driven by the second driving motor.

[0078] The first drive assembly drives the first reflector to compensate for the translation error, with the error △x / △y equal to the correction translation of the first drive motor. The second drive assembly drives the second reflector to compensate for the angular error, with the specific values ​​as described above.

[0079] like Figure 5 As shown, the correction of the above-mentioned high-frequency and low-frequency errors requires the control of the first reflector 11 and the second reflector 21 by the control unit. Its essence is to feedback the electrical signal to the stepper motor or piezoelectric ceramics, and then realize the distance correction. The present invention adopts drive control based on stepper motor and piezoelectric ceramics, that is, a part of the incident laser sampling is performed for position detection, and the origin of the first detection component is used as the reference and the actual spot position is used as the input. The pid calculation is performed to obtain the feedback compensation amount, and the obtained compensation amount is sent to the control unit to control the first reflector to compensate for the beam offset. It can produce a good suppression effect on low-frequency broadband disturbances, and can also be used to eliminate the interference caused by air turbulence. The specific algorithm is:

[0080]

[0081] The proportional control term simply multiplies the error signal by the proportional control constant Kp; the integral control term multiplies the integral constant Ki by the integral of the error signal; and the differential control term generates a signal proportional to the time integral of the error signal. The integral term reduces the steady-state error of the control unit, while the differential term acts as a lead control, minimizing overshoot during the ramp-up process. The PID control parameters Kp, Ki, and Kd can be flexibly adjusted to minimize overshoot and steady-state error, achieving the desired control performance.

[0082] Finally, it is possible to check whether the light spots of the first detection unit and the second detection unit are stable at the detection center. If so, the calibration is terminated. If not, the process returns to the error category judgment to continue the judgment.

[0083] The above process is repeated during the laser processing, and the deviation error of the light beam is always detected and corrected online.

[0084] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention shall be covered by the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. An online correction device for beam pointing jitter for laser processing, characterized in that: It comprises a translation component detection and correction unit (1) and an angle component detection and correction unit (2) which are sequentially arranged along the optical path of an incident light ray (01), and a control unit; The translation component detection and correction unit (1) comprises a first reflector (11), a first drive component, a first beam splitter (12) and a first detection component (13); the first reflector (11) is mounted on the action end of the first drive component and is used to reflect the incident light (01) to form a first reflected light (02); the first drive component is used to adjust the position and angle of the first reflector (11); the first beam splitter (12) splits the first reflected light (02) into a second reflected light (03) and a first transmitted light (04); the first detection component (13) is arranged on the optical path of the second reflected light (03) and is used to receive the second reflected light (0 3); the first detection component (13) comprises a third beam splitter (131), a CCD1 (132) and a PSD1 (133); the third beam splitter (131) is arranged on the optical path of the second reflected light (03) and is used to split the second reflected light (03) into a fifth reflected light (08) and a third transmitted light (09); the CCD1 (132) is arranged on the optical path of the fifth reflected light (08) and is connected to the control unit and is used to receive the fifth reflected light (08); the PSD1 (133) is arranged on the optical path of the third transmitted light (09) and is connected to the control unit and is used to receive the third transmitted light (09); The angle component detection and correction unit (2) comprises a second reflector (21), a second drive assembly, a second beam splitter (22), an optical path extension assembly (23) and a second detection assembly (24); the second reflector (21) is mounted on the action end of the second drive assembly and is used to reflect the first transmitted light (04) to form a third reflected light (05); the second drive assembly is used to adjust the position and angle of the second reflector (21); the second beam splitter (22) splits the third reflected light (05) into a fourth reflected light (06) and a second transmitted light (07); the fourth reflected light (06) is used for laser processing; the optical path extension assembly (23) and the second detection assembly (24) are sequentially arranged along the optical path of the second transmitted light (07); the optical path extension assembly (23) extends the second transmitted light (07) to expand the linear value of its angular error; the second detection component (24) is used to receive the second transmitted light (07) after the linear value of the angular error is expanded; the second detection component (24) includes a fourth beam splitter (241), a CCD2 (242) and a PSD2 (243); the fourth beam splitter (241) is arranged on the optical path of the second transmitted light (07) and is used to split the second transmitted light (07) into a sixth reflected light (010) or a fourth transmitted light (011); the CCD2 (242) is arranged on the sixth reflected light (010) and is connected to the control unit for receiving the sixth reflected light (010); the PSD2 (243) is arranged on the fourth transmitted light (011) and is connected to the control unit for receiving the fourth transmitted light (011); The control unit is connected to the first driving component, the first detection component (13), the second driving component and the second detection component (24) respectively, and is used to control the first driving component to adjust the posture of the first reflector (11) and / or control the second driving component to adjust the posture of the second reflector (21) according to the first detection information of the first detection component (13) and the second detection information of the second detection component (24), so as to correct the fourth reflected light (06); The optical path extension component (23) comprises a third reflector (231), a fourth reflector (232) and a fifth reflector (233); the fourth reflector (232) is parallel to the fifth reflector (233); The third reflector (231) is arranged on the optical path of the second transmitted light (07) and is used to reflect the second transmitted light (07) to the surface of the fourth reflector (232) and to perform multiple reflections between the fifth reflector (233) and the fourth reflector (232); The second detection component (24) is arranged on the optical path of the second transmitted light (07) after multiple reflections; The optical path extension component (23) further comprises a long zoom objective lens (234); The long zoom objective lens (234) is arranged between the second beam splitter (22) and the third reflector (231) and is located on the optical path of the second transmitted light (07) and is used to focus the second transmitted light (07).

2. The laser processing beam pointing jitter online correction device according to claim 1, characterized in that: The fifth reflector (233) is a long-focus cylindrical reflector.

3. The laser processing beam pointing jitter online correction device according to claim 2, characterized in that: The splitting ratio of the first beam splitter (12) is 9:1, wherein the second reflected light (03) accounts for 10% and the first transmitted light (04) accounts for 90%; The splitting ratio of the second beam splitter (22) is 1:9, wherein the fourth reflected light (06) accounts for 90% and the second transmitted light (07) accounts for 10%; The splitting ratio between the third beam splitter (131) and the fourth beam splitter (241) is 1:

1.

4. The laser processing beam pointing jitter online correction device according to claim 3, characterized in that: The first driving component includes a first piezoelectric ceramic and a first driving motor; The first piezoelectric ceramic is arranged on the back of the first reflector (11), and the output end of the first drive motor is connected to the first reflector (11) through the first piezoelectric ceramic; The second driving component includes a second piezoelectric ceramic and a second driving motor; The second piezoelectric ceramic is arranged on the back of the second reflector (21), and the output end of the second drive motor is connected to the second reflector (21) via the second piezoelectric ceramic.

5. The laser processing beam pointing jitter online correction device according to claim 4, characterized in that: The first driving motor and the second driving motor are both stepping motors.

6. A laser processing beam pointing jitter correction method, based on the laser processing beam pointing jitter online correction device according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: The first detection component (13) receives the second reflected light (03) to obtain first detection information, and sends the first detection information to the control unit, while the second detection component (24) receives the second transmitted light (07) to obtain second detection information, and sends the second detection information to the control unit; Step 2: The control unit determines whether the incident light (01) has a translation error and / or an angle error according to the first detection information and the second detection information: If it does not exist, return to step 1 and perform real-time monitoring; If yes, then calculate the angle error according to the second detection information, calculate the translation error according to the first detection information and the second detection information, and then execute step 3; Step 3: the control unit controls the second drive component to adjust the posture of the second reflector (21) according to the calculated angular error; and controls the first drive component to adjust the posture of the first reflector (11) according to the calculated translation error.

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