2.5 D micro-pattern laser processing method based on acousto-optic deflector and galvanometer

Abstract

The invention belongs to the related technical field of laser micro-nano machining, and particularly relates to a 2.5 D micro-pattern laser machining method based on an acousto-optic deflector and a galvanometer, which is realized by adopting a laser device based on combination of an acousto-optic deflection module and the galvanometer, and comprises the following steps: in single track scanning of the galvanometer, according to a preset pulse machining sequence corresponding to a machined pattern, carrying out laser processing on the machined pattern according to a preset pulse processing sequence corresponding to the machined pattern; frequency control signals corresponding to the pulses are input into the two acousto-optic deflectors respectively, so that laser pulse distribution formed on the machined part after single-time track scanning of the galvanometer is shown as the pulse superposition number in the depth direction and the lap joint rate between adjacent pulses in the normal direction of the advancing direction of the galvanometer; the pulse superposition number of each pulse position in the depth direction reflects the processing depth of the pulse position, and the pulse number and the pulse overlap rate of each positioning position in the normal direction of the moving direction of the galvanometer are determined according to the section width and the contour radian in the width direction of a processing graph. According to the invention, the processing of any 2.5 D micro-pattern can be realized.

Description

Technical Field

[0001] This invention belongs to the field of laser micro-nano processing technology, and more specifically, relates to a 2.5D micro-pattern laser processing method based on an acousto-optic deflector and a galvanometer. Background Technology

[0002] Laser 2.5D micro-patterning technology can achieve shape and property control manufacturing at the micron to nanoscale. It is not limited to simple drilling or cutting, but can also be used for the preparation of textures and patterns on material surfaces, flexible printed circuit processing, superhydrophobic preparation, etc., thus having a wide range of applications in microelectronic devices, semiconductor manufacturing, mold manufacturing and other fields.

[0003] With the continuous improvement of laser repetition rate, laser deflection systems for processing 2.5D micro-patterns face higher requirements in terms of processing speed and accuracy. If the processing speed is slow, the high repetition rate laser will cause an increase in the number of pulses received per unit area on the workpiece surface during processing, leading to localized heat accumulation, which in turn results in decreased processing accuracy and prolonged processing time. Therefore, how to fully utilize the advantages of high repetition rate lasers to improve processing efficiency while maintaining processing quality has become a key issue that urgently needs to be addressed in laser deflection systems.

[0004] Currently, 2D laser deflection systems primarily rely on galvanometers. However, when processing micro-patterns, galvanometers require multiple repeated scans of the pattern. Mechanical inertia leads to acceleration / deceleration processes, resulting in "idling time" during trajectory switching, which is time-consuming. Furthermore, the low deflection angular velocity of galvanometers (typically ≤100 rad / s) causes localized heat accumulation in the processed material, easily leading to thermal damage such as melting and recasting layers, thus failing to fully realize the potential of high-repetition-rate lasers. Acousto-optic deflectors utilize the acousto-optic Bragg diffraction effect to achieve high-speed deflection of incident lasers through efficient control of the sound field. They feature no mechanical vibration, high deflection angular velocity (up to 1000 rad / s), short response time (sub-µs), high scanning accuracy (<0.1 µrad), and pulse-by-pulse laser beam control. However, their scanning range is narrow, preventing their independent application in processing.

[0005] In summary, traditional laser 2.5D micro-patterning based on mechanical deflectors suffers from low processing efficiency and accuracy, low energy utilization, and slow deflection speed. While acousto-optic deflectors offer high deflection speed and pulse-by-pulse laser beam control, their narrow scanning range prevents their independent application. Therefore, composite processing systems combining acousto-optic deflectors and galvanometers are gaining traction. These systems allow for dynamic modulation of laser pulse distribution within a single galvanometer scan, reducing the number of repeated galvanometer scans and saving processing time. However, a method for effectively allocating pattern data between these two scanning devices to meet their respective scanning capabilities and collaboratively produce arbitrary 2.5D patterns during 2.5D micro-patterning has yet to be reported. Summary of the Invention

[0006] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a 2.5D micro-pattern laser processing method based on acousto-optic deflector and galvanometer, the purpose of which is to improve the collaborative processing quality of acousto-optic deflector and galvanometer so as to realize the processing of arbitrary 2.5D micro-patterns.

[0007] To achieve the above objectives, according to one aspect of the present invention, a 2.5D micro-pattern laser processing method based on an acousto-optic deflector and a galvanometer is provided. This method employs a laser device based on an acousto-optic deflection module and a galvanometer. The deflection module consists of two orthogonal acousto-optic deflectors. At each positioning position during a single trajectory scan of the galvanometer, by modulating the frequency control signals of the two deflectors, the module can control the laser pulse to fall at any position within the laser scanning area that the module can control at the current positioning position. Each positioning position is the center point of the corresponding laser scanning area. The method includes:

[0008] During the uniform speed scanning of the galvanometer trajectory, according to the preset pulse processing sequence corresponding to any desired processing pattern, the frequency control signals of each pulse are input to the two deflectors in the acousto-optic deflector module, so that the laser pulse distribution formed on the workpiece after the single trajectory scanning of the galvanometer is manifested as the number of pulse superpositions in the depth direction and the pulse overlap rate between adjacent pulses in the normal direction of the galvanometer travel direction, thereby realizing the corresponding desired processing pattern.

[0009] Among them, the pulse overlap rate between two adjacent pulses in the depth direction at the same processing position is 100% in the normal direction of the galvanometer travel direction. The number of pulses superimposed in the depth direction at each pulse position reflects the processing depth at that pulse position. The number of pulses and the pulse overlap rate in the normal direction of the galvanometer travel direction are determined according to the width of the section and the contour curvature in the width direction of the processing pattern.

[0010] The pulse processing sequence is determined as follows: based on the required processing pattern, the depth and shape information of each position of the processing pattern are determined. Combined with the actual single-pass processing experiment under specific laser parameters and processing material conditions, the depth and shape information are converted into laser pulse distribution and sorted according to the required processing sequence to obtain the preset pulse processing sequence; the central axis in the length direction of the required processing pattern is the single-pass trajectory of the galvanometer.

[0011] Furthermore, when the required machining pattern is a trapezoidal groove or a V-shaped groove, the corresponding pulse distribution design is as follows:

[0012] The pulse overlap rates in the normal and tangential directions at each positioning position along the galvanometer travel direction are fixed. The number of pulses in the normal direction is determined based on the width of the groove and the fixed pulse overlap rate in the normal direction. The number of laser pulses on the central axis is determined based on the length of the central axis of the groove and the fixed pulse overlap rate in the tangential direction.

[0013] A single-pass machining experiment was conducted based on the pulse overlap rate in the normal and tangential directions to determine the machining depth at each pulse position. Combined with the machining depth to be processed at the pulse position of the machining pattern, the number of repeated laser pulses in the depth direction at that pulse position was determined as the number of laser pulse superpositions in the depth direction. The single-pass machining experiment was achieved by uniformly scanning the galvanometer trajectory once.

[0014] Furthermore, when the required machining pattern is an inverted conical groove with a certain curvature, the corresponding pulse distribution design is as follows:

[0015] By changing the pulse overlap rate between adjacent pulses in the normal and tangential directions, a single-pass machining experiment was conducted to determine the depth direction profile formed under different combinations of pulse overlap rates. This determined the pulse overlap rate between adjacent pulses in the normal and tangential directions corresponding to the depth direction profile of the desired machining pattern. Furthermore, the number of pulses in the normal and tangential directions was determined by combining the width and length of the desired machining pattern. The single-pass machining experiment was achieved by uniform scanning of the galvanometer trajectory in a single pass.

[0016] The pulse overlap rate between adjacent pulses in the normal and tangential directions corresponding to the determined depth direction contour of the desired processed graphic, as well as the number of pulses in the normal and tangential directions, are used as the pulse distribution for a single pass of processing.

[0017] Based on the required depth of the pattern to be processed, the number of repeated pulses at each pulse position is determined, thereby determining the number of processing passes required based on the pulse distribution of a single-pass processing experiment, and finally determining the pulse distribution of the inverted conical groove.

[0018] Furthermore, when the required machining pattern is an arc-shaped groove, the corresponding pulse distribution is designed as follows:

[0019] By changing the pulse overlap rate between adjacent pulses in the normal and tangential directions and the number of repeated pulses at each pulse position, a single-pass machining experiment is conducted to determine the depth direction profile formed under the corresponding pulse distribution combination. This determines the pulse overlap rate between adjacent pulses in the normal and tangential directions and the number of repeated pulses at each pulse position corresponding to the depth direction profile of the required machining pattern. Furthermore, the number of pulses in the normal and tangential directions is determined by combining the width and length of the required machining pattern.

[0020] The pulse overlap rate between adjacent pulses in the normal and tangential directions corresponding to the determined depth profile of the desired machining pattern, the number of repeated pulses at each pulse position, and the number of pulses in the normal and tangential directions are used as the pulse distribution for a single machining experiment.

[0021] Based on the required depth of the pattern to be processed, the total number of repeated pulses at each pulse position is determined, thereby determining the number of processing passes required based on the pulse distribution of the single-pass processing experiment, and finally determining the pulse distribution of the arc-shaped groove.

[0022] Furthermore, the actual machining depth h at each pulse position is:

[0023]

[0024] In the formula, E eff E represents the theoretical processing depth. p For single-pulse energy, N overlap The pulse overlap ratio of two adjacent pulses arranged on the processing surface is given by denoted by denoted by D, where D is the laser beam spot radius, and k represents the deviation coefficient between theoretical and experimental processing.

[0025] Furthermore, the forward velocity V of the galvanometer is:

[0026]

[0027] In the formula, L s The length of the galvanometer travel is represented by L, which is the length of the centerline of the graphic to be processed; M is the galvanometer travel distance L. s The number of laser pulses deflected by the acousto-optic deflection module within the length, i.e., the number of pulses in the pulse distribution; F is the repetition frequency of the pulsed laser.

[0028] Furthermore, the preset pulse processing sequence is as follows:

[0029] The laser pulses that fall on the workpiece in chronological order are arbitrarily distributed in any direction relative to the galvanometer's travel direction, and are not processed sequentially along the normal direction of the galvanometer's travel direction.

[0030] According to another aspect of the present invention, a 2.5D micro-patterning laser processing device based on an acousto-optic deflector and a galvanometer is provided, comprising: a pulsed laser, an acousto-optic deflection module, a signal control unit, a beam relay module, a galvanometer, a flat-field focusing lens, and a central control unit.

[0031] The system includes a pulsed laser for supplying pulsed laser light to the acousto-optic deflection module; the acousto-optic deflection module, controlled by a frequency control signal from a signal control unit, changes the deflection angle of the first-order diffracted beam output by the acousto-optic deflection module to deflect the first-order diffracted beam to any position within the laser scanning area controlled by the module at the current galvanometer scanning position; a beam relay module maintains the beam quality of the diffracted beam output by the acousto-optic deflection module through optical transmission and blocks beams of other diffraction orders from passing through; a galvanometer moves along the processing trajectory under the control of a central control unit to position the first-order diffracted beam deflected by the acousto-optic deflection module; the first-order diffracted beam is reflected by the galvanometer to a flat-field focusing lens; the flat-field focusing lens converges the beam output by the galvanometer to a focal point, placing the processing component at the focal point for processing; and a central control unit connects to the signal synchronization control unit, galvanometer, and displacement stage, sending control signals to these components to execute the steps of the 2.5D micro-pattern laser processing method described above.

[0032] In summary, compared with the prior art, the technical solutions conceived by this invention have the following main advantages:

[0033] 1. This invention proposes a laser processing method for 2.5D micro-patterns based on an acousto-optic deflector and a galvanometer. The method employs a laser device combining an acousto-optic deflector and a galvanometer to process 2.5D micro-patterns. With this laser device, the frequency of the input driving signal determines the deflection position of the diffracted light, thereby controlling the distribution and ablation degree of the laser pulses on the material surface. By controlling the driving signal frequency, the overlap of the laser beams and the number of pulse repetitions on the processing surface can be changed, thus altering the ablation shape and depth. Therefore, the morphology of the processed pattern is transformed into the pulse overlap rate in the planar direction and the number of repetitive pulses in the depth direction. Furthermore, the pulse distribution is ordered in a specified sequence, resulting in enhanced executability. Processing is performed according to a pre-designed pulse processing sequence, forming a pulse distribution on the workpiece to achieve the desired pattern. This method is simple, convenient, and highly accurate. Through the collaborative work of the two devices, the galvanometer can generate complex 2.5D microstructures with only a single scan, while traditional single-galvanometer processing requires multiple repeated scans accompanied by acceleration / deceleration time. This method significantly improves processing efficiency.

[0034] 2. Based on the high-speed random access scanning capability of the acousto-optic deflector, this invention proposes that laser pulses falling on the workpiece in a time sequence be arbitrarily distributed in any direction relative to the galvanometer's travel direction, rather than sequentially processed along the normal direction of the galvanometer's travel direction. The random deflection pulse processing method can process to a greater depth in one pass. The high-speed random access scanning capability of the acousto-optic deflector can solve the heat accumulation problem caused by high repetition rate lasers. Ultimately, it can achieve rapid processing of complex 2.5D micro-patterns while reducing local heat accumulation, which can greatly improve processing efficiency and accuracy, and meet the needs of high-speed, high-efficiency, and high-quality processing. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of a 2.5D micro-patterning laser processing device based on an acousto-optic deflector and a galvanometer provided by the present invention;

[0036] Figure 2 This is a schematic diagram of the overall structure of the acousto-optic deflection module in this invention;

[0037] Figure 3 This is a schematic diagram of the beam relay module in this invention;

[0038] Figure 4 This is a schematic diagram of the collaborative processing of the acousto-optic deflection module and the galvanometer in this invention;

[0039] Figure 5 This is a schematic diagram illustrating the different deflection strategies employed by the acousto-optic deflection module when it processes the same pattern in collaboration with a galvanometer in this invention.

[0040] Figure 6 This is a schematic diagram showing the number of processing pulses and the ablation depth at a certain location in this invention;

[0041] Figure 7 This is a schematic diagram of how the acousto-optic deflection module and the galvanometer are used in collaboration to process 2.5D micro-patterns of trapezoidal grooves in an embodiment of the present invention;

[0042] Figure 8 This is a schematic diagram of the 2.5D micro-pattern of a V-shaped groove processed in collaboration with an acousto-optic deflection module and a galvanometer in an embodiment of the present invention;

[0043] Figure 9 This is a schematic diagram of the 2.5D micro-pattern of an inverted conical groove processed in collaboration with an acousto-optic deflection module and a galvanometer in an embodiment of the present invention;

[0044] Figure 10 This is a schematic diagram of how the acousto-optic deflection module and the galvanometer are used in conjunction to process 2.5D micro-patterns of arc-shaped grooves in an embodiment of the present invention;

[0045] Figure 11This is a schematic diagram of the process of processing cylindrical shapes and arbitrary 2.5D micro-shapes using an acousto-optic deflection module and a galvanometer in accordance with an embodiment of the present invention; wherein, (a) is a schematic diagram of cylindrical processing; and (b) is a schematic diagram of processing any curved trapezoid.

[0046] In the diagram: 1. Pulsed laser; 2. Beam expander and collimator; 3. Mirror group; 4. Acousto-optic deflection module; 5. Signal control unit; 6. Beam relay module; 7. Interstage mirror; 8. Galvanometer; 9. Flat field focusing mirror; 10. Processing material; 11. Displacement stage; 12. Central control unit; 41. First acousto-optic deflection module; 42. Second acousto-optic deflection module; 401. Drive signal source; 402. Ultrasonic transducer; 403. Acousto-optic medium; 403. Sound absorption device; 601. First relay lens; 602. Aperture; 603. Second relay lens. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0048] Example 1

[0049] A 2.5D micro-pattern laser processing method based on acousto-optic deflectors and a galvanometer is disclosed. The method employs a laser device combining an acousto-optic deflection module and a galvanometer. The deflection module consists of two orthogonal acousto-optic deflectors. At each positioning position during a single trajectory scan of the galvanometer, by modulating the frequency control signals of the two deflectors, the module can control the laser pulse to fall at any position within the laser scanning area controlled by the module at the current positioning position. After scanning, a laser pulse distribution is formed; each positioning position is the center point of the corresponding laser scanning area. The method includes:

[0050] During the uniform speed scanning of the galvanometer trajectory, according to the preset pulse processing sequence corresponding to any desired processing pattern, the frequency control signals of each pulse are input to the two deflectors in the acousto-optic deflector module, so that the laser pulse distribution formed on the workpiece after the single trajectory scanning of the galvanometer is manifested as the number of pulse superpositions in the depth direction and the pulse overlap rate between adjacent pulses in the normal direction of the galvanometer travel direction, thereby realizing the corresponding desired processing pattern.

[0051] Among them, the pulse overlap rate between two adjacent pulses in the depth direction at the same processing position is 100% in the normal direction of the galvanometer travel direction. The number of pulses superimposed in the depth direction at each pulse position reflects the processing depth at that pulse position. The number of pulses and the pulse overlap rate in the normal direction of the galvanometer travel direction are determined according to the width of the section and the contour curvature in the width direction of the processing pattern.

[0052] The pulse processing sequence is determined as follows: based on the required processing pattern, the depth and shape information of each position of the processing pattern are determined. Combined with the actual processing experiment under specific laser parameters and processing material conditions, the depth and shape information are converted into laser pulse distribution and sorted according to the required processing sequence to obtain the preset pulse processing sequence; the central axis of the length direction of the required processing pattern is the single travel trajectory of the galvanometer.

[0053] The composition and structure of the laser device used in this embodiment can be existing, as long as the laser device meets the following requirements: its deflection module consists of two orthogonal acousto-optic deflectors. At each positioning position during a single trajectory scan of the galvanometer, by modulating the frequency control signals of the two deflectors, the module can control the laser pulse to fall at any position within the laser scanning area that the module can control at the current positioning position, and form a laser pulse distribution after the scan is completed; each positioning position is the center point of the corresponding laser scanning area.

[0054] As a conventional laser device, such as Figure 1 As shown, it includes: a pulsed laser 1, a beam expander and collimator module 2, a mirror group 3, a first acousto-optic deflection module 41, a second acousto-optic deflection module 42, a signal control unit 5, a beam relay module 6, a galvanometer 8, and a central control unit 12 arranged in sequence.

[0055] The pulsed laser 1 is used to generate a pulsed laser beam with variable frequency and variable average power, wherein the frequency of the pulsed laser 1 is variable between 100 and 1000 kHz.

[0056] The reflector group 3 is used to adjust the angle at which the pulsed laser output from the pulsed laser 1 enters the first acousto-optic deflection module 41 and the second acousto-optic deflection module 42, so as to meet the Bragg angle incident requirements.

[0057] The signal control unit 5 simultaneously controls the first acousto-optic deflection module 41 and the second acousto-optic deflection module 42, so that they are loaded with a given driving signal frequency, so that the beam is deflected to a specified position on the processing surface.

[0058] The structures of the acousto-optic deflection module 41 and the second acousto-optic deflection module 42 are as follows: Figure 2As shown, the deflection angle (θ) of the first-order diffracted beam of the pulsed laser output by the pulsed laser 1 is determined by the driving signal frequency (f), and can be expressed by the formula:

[0059]

[0060] In the formula, λ is the wavelength of the laser output, and V s The speed at which ultrasound travels in an acousto-optic medium;

[0061] As shown by the formula, the deflection angle of the first-order diffracted beam is directly proportional to the driving frequency. By changing the driving frequency, the deflection direction of the diffracted light can be linearly controlled. The acousto-optic medium is selected from crystals such as quartz and tellurium oxide, or ceramics.

[0062] The beam relay module 6 transmits the deflected beam output from the first acousto-optic deflection module 41 and the second acousto-optic deflection module 42 to the galvanometer with high quality. The beam relay module 6 can also block other diffraction beams except for the first-order diffraction beam.

[0063] The galvanometer 8 deflects the first-order diffraction beam to the processing surface, providing coarse positioning for the first-order diffraction beam and guiding the beam for large-scale processing.

[0064] Optionally, the device for laser processing of 2.5D micro-patterns based on acousto-optic deflectors and galvanometers also includes a beam expander and collimator module 2, an interstage mirror 7, a displacement stage 11, and a central control unit 12.

[0065] The beam expanding and collimating module 2 expands and collimates the pulsed laser output from the pulsed laser 1 to form a parallel beam for emission;

[0066] The interstage reflector 7 is positioned between the acousto-optic deflection module 42 and the galvanometer 8 to adjust the position of the diffracted light at the center frequency so that the diffracted beam at the center frequency is incident directly into the galvanometer 8.

[0067] The central control unit 12 pre-stores the method for processing the machining component 10 and related data, converting it into motion path data for the acousto-optic deflection module 4 and the galvanometer 8. The central control unit 12 is connected to the signal control unit 5, the galvanometer 8, and the displacement stage 11. It controls the scanning speed and machining trajectory of the galvanometer 8 according to the machining data, controls the drive signals emitted by the signal control unit 5 to the first acousto-optic deflection module 41 and the second acousto-optic deflection module 42 to load corresponding radio frequency signals, and controls the movement direction and Z-axis feed distance of the displacement stage 11 to perform the pre-set machining program.

[0068] refer to Figure 2The acousto-optic deflection module 4 includes a first acousto-optic deflection module 41 and a second acousto-optic deflection module 42. The acousto-optic deflection module consists of a driving signal source 401, an ultrasonic transducer 402, an acousto-optic medium 403, and a sound absorption device 404. One end of the electrode layer at both ends of the piezoelectric layer in the ultrasonic transducer 402 is connected to the driving signal source 401, and the other end is connected to the acousto-optic medium 403. The driving signal source 401 can output radio frequency signals of different frequencies. The driving signal source 401 can output radio frequency signals of different frequencies, realizing the change from mechanical vibration to the same frequency sound signal at the position of the ultrasonic transducer 402, thereby generating ultrasonic waves in the acousto-optic medium 403, causing the refractive index of the acousto-optic medium 403 to change. At the same time, the sound absorption device 404 absorbs the ultrasonic waves passing through the acousto-optic medium 403, making the ultrasonic waves in the acousto-optic medium 403 traveling waves. In this embodiment, the material of the acousto-optic medium 403 is quartz crystal, the material of the ultrasonic transducer 402 is lithium niobate crystal, and the frequency range of the radio frequency signal output by the driving signal source 401 is 140MHz to 200MHz, with a center frequency of 170MHz.

[0069] The first acoustic-optic deflection module 41 and the second acoustic-optic deflection module 42 use the same type of acoustic-optic medium and driving signal source, and generate corresponding angle deflection of the beam according to the control signal of the signal control unit 5.

[0070] refer to Figure 3 The beam relay module 6 includes a first relay lens 601, an aperture 602, and a second relay lens 603. In this embodiment, for example, the first relay lens 601 and the second relay lens 603 are both plano-convex lenses with a focal length of 500mm. The aperture 602 is made of copper and can withstand high-power laser ablation.

[0071] refer to Figure 4 In the left figure, when the acousto-optic deflection module 4 and the galvanometer 8 work together in the device, the galvanometer 8 moves at a constant speed along a predetermined trajectory. The acousto-optic deflection module 4 deflects the pulses in the direction of travel of the galvanometer 8 to a predetermined position. The relationship between the traveling positioning position of the galvanometer 8 and the processing position should satisfy:

[0072]

[0073] In the formula, ΔX A The axial vector offset of the first acousto-optic deflection module 41; ΔY A For the axial vector offset of the second acousto-optic deflection module 42; (X P ,Y P ) represents the position coordinates of the processed graphic, (X) G ,Y G ) represents the positioning coordinates of the galvanometer 8 during its movement.

[0074] Since the processing pulse position and pulse quantity, as well as the motion trajectory of the galvanometer 8, are all pre-stored in the central control unit 12, the vector offset data of the acousto-optic deflection module 4 can be calculated using the above formula. The offset should be within the processing area of ​​the acousto-optic deflection module 4. The above offset data is also stored in the central control unit 12. The data conversion module in the central control unit 12 converts the offset data into frequency, which can be expressed by the formula:

[0075]

[0076] In the formula, f x f y The frequency data in the first acousto-optic deflection module 41 and the second acousto-optic deflection module 42 during processing; F Theta The focal length of the flat-field focusing lens 9 is given.

[0077] The central control unit 12 sends frequency data to the signal control unit 5, which then generates a specified frequency signal and sends it to the first acousto-optic deflection module 41 and the second acousto-optic deflection module 42, allowing the position of the deflection pulse to be changed as specified. Once both data are calculated, they can move synchronously, arranging the pulsed laser at the specified positions. The interval d between the pulsed laser spots on the tangent and normal lines along the travel direction of the galvanometer 8 on the processing surface is defined as follows: v and d h It can be modified according to the actual processing shape, thus directly forming micro-shapes with a certain width.

[0078] refer to Figure 4 In the right figure, in this embodiment, the focal length of the flat-field focusing lens 9 is 100mm, the frequency of the pulsed laser 1 is 355nm, and the size L of the square processing area formed by the acousto-optic deflection module 4 is... AOD =370um, the center of the processing area is obtained at a driving frequency of 170MHz for both acousto-optic deflection modules, and the center of the processing area is on the galvanometer trajectory. When the acousto-optic deflection module 4 deflects the laser beam, it deflects the beam at the center of the processing area to the processing position, which can exist at any position within the processing area at this time.

[0079] refer to Figure 5 When the galvanometer 8 moves along the micro-pattern trajectory, the acousto-optic deflection module 4 can deflect the laser beam in two ways: one is to deflect the laser pulses sequentially along the normal direction of the galvanometer 8, i.e., sequential deflection. Figure 5 The left image shows one method; another method utilizes an acousto-optic deflector with random access deflection capability, allowing pulses to be arbitrarily distributed along the normal or tangential direction of the galvanometer 8. Figure 5The right figure shows that, as long as it is within the compensation capability of the acousto-optic deflection module, both methods can meet the processing requirements of the acousto-optic deflection module, providing great flexibility and making them preferred implementation methods.

[0080] refer to Figure 6 When the laser beam output from pulsed laser 1 is focused by the flat-field focusing mirror 9, it will ablate the material on the processing surface. The ablation depth h is related to the energy density E. eff The relationship between them can be represented as:

[0081]

[0082] In the formula, E eff E represents the theoretical processing depth. p For single-pulse energy, N overlap The pulse overlap ratio of two adjacent pulses arranged on the processing surface is given by denoted by denoted by D, where D is the laser beam spot radius, and k represents the deviation coefficient between theoretical and experimental processing.

[0083] From the above formula, it can be seen that when the laser beam spot radius D and the single pulse energy E p At a given time, the overlap rate N between the ablation depth h and the laser beams arranged on the processing surface overlap The deflection angle of the diffracted laser beam changes when the signal control unit 5 changes the driving frequency acting on the two acousto-optic deflection modules 41 and 42, thereby changing the overlap rate between pulses. For example, a small change in deflection angle will cause the pulses to be densely distributed in a local area (i.e., high overlap rate), thus increasing the ablation depth; conversely, a large change in deflection angle will disperse the pulses (low overlap rate), reducing the ablation depth. Therefore, by changing the deflection angle of the diffracted beam, processing patterns with different depths and morphologies can be obtained. However, when a certain position is subjected to excessive pulse superposition ablation, heat will accumulate rapidly at that processing position, causing thermal damage such as melting and recasting layers, making the ablation depth unpredictable. By utilizing the random access deflection function of the acousto-optic deflector to disperse the pulse distribution within a certain area, the thermal effect can be greatly reduced, and patterns with deeper ablation depths can be processed while meeting processing quality requirements.

[0084] This embodiment utilizes the high-speed scanning capability of an acousto-optic deflector. The deflection angle of the acousto-optic deflector is proportional to the frequency of the input driving signal, and the deflection range is proportional to its own Bragg bandwidth. Beam deflection is achieved through high-speed control of the sound field. There are no mechanical parts, no mechanical inertia, and high processing efficiency. Furthermore, within a controllable laser frequency, the acousto-optic deflector can be controlled pulse-by-pulse. Using two orthogonally placed acousto-optic deflector modules, a square scanning area is formed, enabling dynamic beam control. This makes the overall system flexible and pulse-controllable. Simultaneously, the wide-range processing capability of the galvanometer allows the system to process patterns much larger than the scanning area of ​​the acousto-optic deflector, resulting in greater adaptability. This embodiment's method is based on a laser device where the input drive signal frequency determines the diffraction light deflection position, thereby controlling the distribution and ablation degree of the laser pulse on the material surface. By controlling the drive signal frequency, the overlap of the laser beams and the number of pulse repetitions on the processing surface can be changed, thus altering the ablation shape and depth. Therefore, the morphology of the processed pattern is converted into the pulse overlap rate in the planar direction and the number of repetition pulses in the depth direction. Furthermore, the converted pulse distributions are ordered in a specified sequence, resulting in enhanced executability. Processing is performed using a pre-designed pulse processing sequence, forming a pulse distribution on the workpiece to achieve the desired pattern. This method is simple, convenient, and highly accurate. In this embodiment, the two devices work together; the galvanometer can generate complex 2.5D microstructures with only a single scan, while traditional single-galvanometer processing requires multiple repeated scans accompanied by acceleration / deceleration time. This method significantly improves processing efficiency. The optical elements used in the laser device are mostly high-damage-threshold crystals such as quartz and tellurium oxide, possessing extremely high damage thresholds.

[0085] Preferably, before performing galvanometer scanning and pulse processing, the method further includes:

[0086] Based on the required processing pattern, the depth and morphology information of each position of the processing pattern are determined. Combined with the actual processing experiments under specific laser parameters and processing material conditions, the depth and morphology information are converted into laser pulse distribution and sorted according to the required processing order to obtain the preset pulse processing order.

[0087] Extract the central axis along the length of the desired processing pattern as the single travel trajectory of the galvanometer.

[0088] As a preferred embodiment, when the required processing pattern is a trapezoidal groove or a V-shaped groove, the corresponding pulse distribution is designed as follows:

[0089] The pulse overlap rate in the normal and tangential directions of the galvanometer travel direction is fixed at each positioning position. The number of pulses in the normal direction is determined based on the width of the groove and the fixed pulse overlap rate in the normal direction. The number of laser pulses on the central axis is determined based on the length of the central axis of the groove and the fixed pulse overlap rate in the tangential direction.

[0090] A single-pass machining experiment was conducted based on the pulse overlap rate in the normal and tangential directions to determine the machining depth at each pulse position. Combined with the machining depth to be processed at the pulse position of the machining pattern, the number of repeated laser pulses in the depth direction at that pulse position was determined as the number of laser pulse superpositions in the depth direction. The single-pass machining experiment was achieved by uniformly scanning the galvanometer trajectory once.

[0091] refer to Figure 7 Trapezoidal grooves are processed using a laser device based on an acousto-optic deflector and a galvanometer. In this embodiment, the laser parameters are: a single pulse energy of 40 μJ and a spot size of 20 μm. First, based on the specific laser parameters and the processing material, the pulse overlap rate in the normal and tangential directions of the galvanometer's travel direction is set, and a single-pass processing experiment is conducted to determine the pulse positions in the normal and tangential directions along the galvanometer's travel direction under the set pulse overlap rate, as well as the processing depth at each pulse position. Based on the processing depth of the pattern at a certain pulse position, the number of repeated laser pulses in the depth direction at that pulse position is determined as the number of laser pulse superpositions in the depth direction. The superimposed pulses can be achieved by controlling the signal control unit 5 to send signals of the same frequency to the acousto-optic deflection module 4, thus enabling repeated processing at the same position a different number of times. Secondly, the number of pulses in the normal direction of the traveling galvanometer 8 is determined based on the groove width and the set fixed pulse overlap rate. The number of pulses over the traveling distance of the galvanometer is calculated based on the length of the processed pattern and the fixed pulse overlap rate, and then derived using the set overlap rate in the galvanometer tangential direction. Finally, the total number of processing pulses and the relative distribution between each pulse are obtained. During processing... Figure 7 When machining trapezoidal grooves, the groove at the center should be deeper than those on the sides. That is, if pulses overlap N times at a certain location in the grooves on the sides, then pulses at a certain location in the groove at the center will overlap 2*N times. If the machining depth is shallow, pulse overlap will not cause heat accumulation, and a sequential machining method can be used, deflecting the pulses sequentially according to the normal direction of the galvanometer's movement. If the machining depth is deep, a random access machining method can be used, refer to [reference needed]. Figure 6 The pulses are randomly deflected in the normal and tangential directions of the galvanometer's travel direction to avoid heat accumulation and ultimately complete the processing of the pattern.

[0092] refer to Figure 8 When the pulse overlap rate is consistent along the normal direction of the galvanometer's travel direction, but the number of superimposed pulses decreases from the center to both sides, a V-shaped groove machining effect can be obtained. Similarly, the machining method can adopt sequential or random deflection pulse machining, with the random deflection pulse machining method machining a deeper depth in one pass.

[0093] Furthermore, if the actual processing depth does not meet the processing requirements, it is necessary to measure the focal depth formed by the laser on the focusing lens and compare it with the actual processing depth. The generated pulse distribution is then layered according to the actual maximum processing depth, and the number of pulse repetitions in the depth direction is reduced accordingly, converting it into the processing repetition count. That is, after the galvanometer 8 completes one movement along the trajectory, it returns to the starting point, while the Z-axis of the displacement stage 11 is advanced upward by the distance of the maximum depth. Then, the galvanometer 8 and the acousto-optic deflection module 4 continue to process collaboratively until the number of pulse repetitions in the depth direction is completed.

[0094] As a preferred embodiment, when the required processing pattern is an inverted conical groove with a certain curvature, the corresponding pulse distribution is designed as follows:

[0095] By changing the pulse overlap rate between adjacent pulses in the normal and tangential directions, a single-pass machining experiment was conducted to determine the depth direction profile formed under different combinations of pulse overlap rates. This determined the pulse overlap rate between adjacent pulses in the normal and tangential directions corresponding to the depth direction profile of the desired machining pattern. Furthermore, the number of pulses in the normal and tangential directions was determined by combining the width and length of the desired machining pattern. The single-pass machining experiment was achieved by uniform scanning of the galvanometer trajectory in a single pass.

[0096] The pulse overlap rate between adjacent pulses in the normal and tangential directions corresponding to the determined depth direction contour of the desired processed graphic, as well as the number of pulses in the normal and tangential directions, are used as the pulse distribution for a single pass of processing.

[0097] Based on the required depth of the pattern to be processed, the number of repeated pulses at each pulse position is determined, thereby determining the number of processing passes required based on the pulse distribution of a single-pass processing experiment, and finally determining the pulse distribution of the inverted conical groove.

[0098] In practice, the inverted conical groove processing effect is achieved by controlling the pulse overlap rate in the normal direction of the traveling direction of the galvanometer 8.

[0099] refer to Figure 9By controlling the signal control unit 5, whose bandwidth frequency is 140-200MHz, different frequencies are sent to the acousto-optic deflection module 4 during the processing. The deflection angle of the deflected beam on the processing surface varies, resulting in different pulse overlap rates at different positions. During processing, firstly, based on the specific laser parameters and processing material, the pulse overlap rates in the normal and tangential directions of the galvanometer's travel direction are set. A single-pass processing experiment is conducted to obtain the contour characteristics corresponding to different overlap rates. Secondly, based on the width and shape of the processed graphic, the pulse overlap rate distribution is obtained, and the required number of deflections is calculated. Then, the angle to which the acousto-optic deflection module needs to deflect is calculated. Finally, based on the processing depth and the experimental depth obtained from the single-pass processing experiment, the number of superimposed pulses is calculated, ensuring that the number of superimposed pulses at each position remains consistent. By using the signal control unit 5 to send different frequency signals to the acousto-optic deflection module 4, the galvanometer can scan along the trajectory only once to obtain a graphic that meets the processing conditions.

[0100] This invention proposes a method for obtaining the machining effect of inverted conical grooves by using the pulse overlap rate of the normal direction of the variable galvanometer travel trajectory. By utilizing the characteristic of the acousto-optic deflector to deflect the laser beam pulse by pulse, the machining requirements can be met through sequential machining or random deflection pulse machining with less thermal effect. The method is simpler and more reliable.

[0101] As a preferred embodiment, when the required processing pattern is an arc-shaped groove, the corresponding pulse distribution is designed as follows:

[0102] By changing the pulse overlap rate between adjacent pulses in the normal and tangential directions and the number of repeated pulses at each pulse position, a single-pass machining experiment is conducted to determine the depth direction profile formed under the corresponding pulse distribution combination. This determines the pulse overlap rate between adjacent pulses in the normal and tangential directions and the number of repeated pulses at each pulse position corresponding to the depth direction profile of the required machining pattern. Furthermore, the number of pulses in the normal and tangential directions is determined by combining the width and length of the required machining pattern.

[0103] The pulse overlap rate between adjacent pulses in the normal and tangential directions corresponding to the determined depth profile of the desired machining pattern, the number of repeated pulses at each pulse position, and the number of pulses in the normal and tangential directions are used as the pulse distribution for a single machining experiment.

[0104] Based on the required depth of the pattern to be processed, the total number of repeated pulses at each pulse position is determined, thereby determining the number of processing passes required based on the pulse distribution of the single-pass processing experiment, and finally determining the pulse distribution of the arc-shaped groove.

[0105] When the signal control unit provides the center frequency to the acousto-optic deflection module, the beam is at the center of the deflection range. As the galvanometer travels along the machining path, black dots will be formed on the path, such as... Figure 4 As shown in (a). During actual processing, the frequency of the pulsed laser 1 is selected as the frequency used for laser processing. The central control unit 12 stores all relative deflection position data and converts it into a frequency signal in the signal control unit 5. The signal control unit 5 then sends the frequency signal to the acousto-optic deflection module 4. The acousto-optic deflection module 4 deflects sequentially according to the given frequency. The central control unit 12 simultaneously controls the rotation speed of the galvanometer 8, and finally obtains the processed pattern.

[0106] refer to Figure 10 First, based on the specific laser parameters and processing materials mentioned above, the pulse overlap rate in the normal and tangential directions of the galvanometer's travel direction is set, and the number of repetitions along the depth direction is also set. A single-pass processing experiment is conducted to determine the impact of the non-overlap rate and the number of pulse repetitions in the depth direction on the contour. Second, based on the shape of the pattern, the specific pulse overlap rate distribution in the normal and tangential directions of the galvanometer's travel direction and the number of repetitions in the depth direction are calculated, ultimately yielding the overall pulse distribution. After designing the pulse distribution, if the number of superimposed central pulses is small, i.e., the ablation depth is shallow, they can be ordered sequentially according to the normal direction of the galvanometer's travel direction, and then deflected using the acousto-optic deflection module 4. If the overall ablation depth is deep, a random access processing method can be used to deflect pulses within a certain range in the normal and tangential directions of the galvanometer's travel direction, distributing the pulses over a larger area. Furthermore, the same position can be processed discontinuously, reducing local thermal effects.

[0107] This invention provides a novel scanning strategy in which the number of pulse superpositions in the depth direction and the pulse overlap rate in the normal direction of the galvanometer travel direction are both variable, enabling pattern processing of arbitrary shapes and depths and meeting the needs of high-speed and high-quality processing.

[0108] This embodiment uses two orthogonally placed acousto-optic deflection modules to flexibly control the laser beam to deflect to any position within a square scanning area. Combined with the wide-range scanning capability of the galvanometer and displacement stage, the galvanometer can travel along the pattern trajectory only once. The acousto-optic deflection modules fill the processing pattern, achieving technical effects such as trapezoidal grooves, V-shaped grooves, and annular holes. Furthermore, the random access scanning feature of the acousto-optic deflection modules can disperse the laser pulse at different positions within the processing area, avoiding thermal effects and meeting the needs of efficient and high-quality processing.

[0109] In addition, this embodiment meets the needs of more complex and larger-format laser processing of 2.5D micro-graphics by changing the galvanometer trajectory and introducing a displacement stage.

[0110] refer to Figure 11 When the galvanometer 8 moves at a constant speed along a circular or arbitrary spline curve, it processes the corresponding pattern on the processing plane. During processing, the number of pulse superpositions in the depth direction and the pulse overlap rate in the normal direction of the galvanometer's movement direction are designed according to the pattern trajectory. The signal control unit 5 sends a pre-set frequency signal to the acousto-optic deflection module 4. The two work together to process the pattern, greatly improving processing efficiency. When the galvanometer 8 reaches the required processing position, the central control unit 12 controls the displacement stage 11 to move. After moving to the next processing position, the central control unit 12 controls the galvanometer 8 and the acousto-optic deflection module 4 to continue processing the required pattern. The trajectory of the galvanometer is no longer limited to a straight line; as long as the position of the deflected laser pulse is within the processing range formed by the acousto-optic deflection module 4, the pattern can be processed. Therefore, the trajectory of the galvanometer can be customized arbitrarily.

[0111] In this embodiment of the invention, the galvanometer can travel along various paths such as circles or spline curves. The acousto-optic deflection module can still process the required pattern using sequential or random access processing methods. The number of pulse superpositions in the depth direction and the pulse overlap rate in the normal direction of the galvanometer's travel direction can be flexibly varied. Simultaneously, a displacement stage 11 is introduced to dynamically adjust the processing position during the processing, which not only improves processing efficiency but also provides a larger processing area, meeting the needs of high-speed, ultra-large format processing.

[0112] This invention provides a laser processing method for 2.5D micro-patterns based on an acousto-optic deflector and a galvanometer. This method is applied to a laser processing device for 2.5D micro-patterns based on an acousto-optic deflector and a galvanometer, which can achieve efficient laser 2.5D micro-pattern processing. While ensuring processing quality, it greatly improves processing speed and efficiency. Furthermore, it can process according to the processing style required by the user, meeting a variety of practical needs.

[0113] Preferably, the forward velocity V of the galvanometer is:

[0114]

[0115] In the formula, L s The length of the galvanometer travel is represented by L, which is the length of the centerline of the graphic to be processed; M is the galvanometer travel distance L. s The number of laser pulses deflected by the acousto-optic deflection module within the length, i.e., the number of pulses in the pulse distribution; F is the repetition frequency of the pulsed laser. Given the laser frequency F and the galvanometer motion rate V, the position of the galvanometer along the central axis at each pulse moment can be accurately determined.

[0116] By theoretically calculating the speed of the galvanometer and combining it with the acousto-optic deflection module to deflect the pulse at a given frequency, the designed processing pattern can be obtained using this system. Too fast or too slow speed will cause image distortion.

[0117] Example 2

[0118] A 2.5D micro-patterning laser processing device based on an acousto-optic deflector and a galvanometer includes: a pulsed laser, an acousto-optic deflection module, a signal control unit, a beam relay module, a galvanometer, a flat-field focusing lens, and a central control unit.

[0119] The system includes a pulsed laser that provides pulsed laser light to the acousto-optic deflection module; the acousto-optic deflection module, controlled by a frequency control signal from a signal control unit, changes the deflection angle of the first-order diffracted beam output by the acousto-optic deflection module to deflect the first-order diffracted beam to any position within the laser scanning area controlled by the module at the current galvanometer scanning position; a beam relay module maintains the beam quality of the diffracted beam output by the acousto-optic deflection module through optical transmission and blocks beams of other diffraction orders from passing through; a galvanometer moves along the processing trajectory under the control of a central control unit to position the first-order diffracted beam deflected by the acousto-optic deflection module; the first-order diffracted beam is reflected by the galvanometer to a flat-field focusing lens; the flat-field focusing lens converges the beam output by the galvanometer to a focal point, placing the processing component at the focal point for processing; and a central control unit connects to the signal synchronization control unit, galvanometer, and displacement stage, sending control signals to these components to execute the steps of the 2.5D micro-pattern laser processing method described in Example 1.

[0120] In a specific implementation, a pulsed laser provides pulsed laser light, which, after being reflected by a group of mirrors, is incident on the acousto-optic deflection module at a Bragg angle. The acousto-optic deflection module is controlled by a frequency signal from a signal control unit to change the deflection angle of the first-order diffracted beam output by the acousto-optic deflection module, allowing the first-order diffracted beam to be deflected to any position within the processing range formed by the two orthogonal acousto-optic deflection modules. The first-order diffracted beam emitted from the acousto-optic deflection module passes through the beam relay module, which optically transmits the diffracted beam to maintain its quality and blocks beams of other diffraction orders from passing through. The first-order diffracted beam output by the beam relay module passes through the inter-order reflector and reaches the galvanometer, which moves along the processing trajectory to position the first-order diffracted beam deflected by the acousto-optic deflection module. The first-order diffracted beam is reflected by the galvanometer to a flat-field focusing lens, which converges the beam to a focal point, placing the processing component at the focal point for processing.

[0121] The central control unit is connected to the signal synchronization control unit, the galvanometer, and the displacement stage. The central control unit sends control signals to the signal control unit, galvanometer, and displacement stage to ensure synchronized processing. The central control unit includes a graphics processing module, a data conversion module, and a galvanometer motion control module. The graphics processing module records the depth and shape characteristics of each position in the processed graphic. Based on specific laser parameters and processing materials, it conducts actual processing experiments, converting the depth and shape information of the processed graphic into laser pulse distribution. Simultaneously, it extracts the centerline of the graphic path as the galvanometer's processing trajectory. The data conversion module sorts the laser pulses according to a given processing order and processes the data. The processed data is then sent to the signal control unit, which sends a drive signal to the acousto-optic deflection module. The galvanometer motion control module controls the direction and speed of the galvanometer's movement.

[0122] The relevant technical solutions are the same as above, and will not be repeated here.

[0123] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A 2.5D micro-pattern laser processing method based on an acousto-optic deflector and a galvanometer, characterized in that, A laser device based on an acousto-optic deflection module and a galvanometer is used. The deflection module consists of two orthogonal acousto-optic deflectors. At each positioning position during a single trajectory scan of the galvanometer, the frequency control signals of the two deflectors are modulated to ensure that the module controls the laser pulse to fall at any position within the laser scanning area that the module can control at the current positioning position; each positioning position is the center point of the corresponding laser scanning area; the method includes: During the uniform speed scanning of the galvanometer trajectory, according to the preset pulse processing sequence corresponding to any desired processing pattern, the frequency control signals of each pulse are input to the two deflectors in the acousto-optic deflector module, so that the laser pulse distribution formed on the workpiece after the single trajectory scanning of the galvanometer is manifested as the number of pulse superpositions in the depth direction and the pulse overlap rate between adjacent pulses in the normal direction of the galvanometer travel direction, thereby realizing the corresponding desired processing pattern. Among them, the pulse overlap rate between two adjacent pulses in the depth direction at the same processing position is 100% in the normal direction of the galvanometer travel direction. The number of pulses superimposed in the depth direction at each pulse position reflects the processing depth at that pulse position. The number of pulses and the pulse overlap rate in the normal direction of the galvanometer travel direction are determined according to the width of the section and the contour curvature in the width direction of the processing pattern. The pulse processing sequence is determined as follows: the depth and shape information of each position of the graphic to be processed are determined, and combined with the actual single-pass processing experiment under specific laser parameters and processing material conditions, the depth and shape information of the graphic to be processed is converted into laser pulse distribution, and sorted according to the required processing sequence to obtain the preset pulse processing sequence; the central axis of the length direction of the graphic to be processed is the single-pass trajectory of the galvanometer.

2. The 2.5D micro-pattern laser processing method as described in claim 1, characterized in that, When the required machining pattern is a trapezoidal groove or a V-shaped groove, the corresponding pulse distribution design is as follows: The pulse overlap rate in the normal and tangential directions at each positioning position in the galvanometer travel direction is fixed. The number of pulses in the normal direction is determined based on the width of the groove and the fixed pulse overlap rate in the normal direction. The number of laser pulses on the central axis is determined based on the length of the central axis of the trench and the fixed pulse overlap rate in the tangential direction. A single-pass machining experiment was conducted based on the pulse overlap rate in the normal and tangential directions to determine the machining depth at each pulse position. Combined with the machining depth to be processed at the pulse position of the machining pattern, the number of repeated laser pulses in the depth direction at that pulse position was determined as the number of laser pulse superpositions in the depth direction. The single-pass machining experiment was achieved by uniformly scanning the galvanometer trajectory once.

3. The 2.5D micro-pattern laser processing method as described in claim 1, characterized in that, When the required machining pattern is an inverted conical groove with a certain curvature, the corresponding pulse distribution design is as follows: By changing the pulse overlap rate between adjacent pulses in the normal and tangential directions, a single-pass machining experiment was conducted to determine the depth direction profile formed under different combinations of pulse overlap rates. This determined the pulse overlap rate between adjacent pulses in the normal and tangential directions corresponding to the depth direction profile of the desired machining pattern. Furthermore, the number of pulses in the normal and tangential directions was determined by combining the width and length of the desired machining pattern. The single-pass machining experiment was achieved by uniform scanning of the galvanometer trajectory in a single pass. The pulse overlap rate between adjacent pulses in the normal and tangential directions corresponding to the determined depth direction contour of the desired processed graphic, as well as the number of pulses in the normal and tangential directions, are used as the pulse distribution for a single pass of processing. Based on the required depth of the pattern to be processed, the number of repeated pulses at each pulse position is determined, thereby determining the number of processing passes required based on the pulse distribution of a single-pass processing experiment, and finally determining the pulse distribution of the inverted conical groove.

4. The 2.5D micro-pattern laser processing method as described in claim 1, characterized in that, When the required machining pattern is an arc-shaped groove, the corresponding pulse distribution design is as follows: By changing the pulse overlap rate between adjacent pulses in the normal and tangential directions and the number of repeated pulses at each pulse position, a single-pass machining experiment is conducted to determine the depth direction profile formed under the corresponding pulse distribution combination. This determines the pulse overlap rate between adjacent pulses in the normal and tangential directions and the number of repeated pulses at each pulse position corresponding to the depth direction profile of the required machining pattern. Furthermore, the number of pulses in the normal and tangential directions is determined by combining the width and length of the required machining pattern. The pulse overlap rate between adjacent pulses in the normal and tangential directions corresponding to the determined depth profile of the desired machining pattern, the number of repeated pulses at each pulse position, and the number of pulses in the normal and tangential directions are used as the pulse distribution for a single machining experiment. Based on the required depth of the pattern to be processed, the total number of repeated pulses at each pulse position is determined, thereby determining the number of processing passes required based on the pulse distribution of the single-pass processing experiment, and finally determining the pulse distribution of the arc-shaped groove.

5. The 2.5D micro-pattern laser processing method as described in claim 1, characterized in that, The actual machining depth h at each pulse position is: In the formula, E eff E represents the theoretical processing depth. p For single-pulse energy, N overlap The pulse overlap ratio of two adjacent pulses arranged on the processing surface is given by denoted by denoted by D, where D is the laser beam spot radius, and k represents the deviation coefficient between theoretical and experimental processing.

6. The 2.5D micro-pattern laser processing method as described in claim 1, characterized in that, The forward velocity V of the galvanometer is: In the formula, L s The length of the galvanometer travel is represented by L, which is the length of the centerline of the graphic to be processed; M is the galvanometer travel distance L. s The number of laser pulses deflected by the acousto-optic deflection module within the length, i.e., the number of pulses in the pulse distribution; F is the repetition frequency of the pulsed laser.

7. The 2.5D micro-pattern laser processing method according to any one of claims 1 to 6, characterized in that, The preset pulse processing sequence is as follows: The laser pulses that fall on the workpiece in chronological order are arbitrarily distributed in any direction relative to the galvanometer's travel direction, and are not processed sequentially along the normal direction of the galvanometer's travel direction.

8. A 2.5D micro-pattern laser processing device based on an acousto-optic deflector and a galvanometer, characterized in that, include: Pulsed laser, acousto-optic deflection module, signal control unit, beam relay module, galvanometer, flat-field focusing lens, and central control unit; The system includes a pulsed laser that provides pulsed laser light to the acousto-optic deflection module; the acousto-optic deflection module, controlled by a frequency control signal from a signal control unit, is used to change the deflection angle of the first-order diffracted beam output by the acousto-optic deflection module, so as to deflect the first-order diffracted beam to any position within the laser scanning area that the module can control at the current galvanometer scanning position; a beam relay module is used to maintain the beam quality of the diffracted beam output by the acousto-optic deflection module through optical transmission and to block the passage of beams of other diffraction orders; a galvanometer is used to move along the processing trajectory under the control of a central control unit to provide a reference positioning for the first-order diffracted beam deflected out by the acousto-optic deflection module; the first-order diffracted beam enters the flat-field focusing lens after being reflected by the galvanometer; the flat-field focusing lens is used to converge the beam output by the galvanometer to the focal point and place the processing part at the focal point for processing; and a central control unit is used to connect to the signal synchronization control unit, the galvanometer, and the displacement stage, and to send control signals to the signal control unit, the galvanometer, and the displacement stage to execute the steps of the 2.5D micro-pattern laser processing method as described in any one of claims 1 to 7.

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