Energy segment active addressing sub-spot laser processing method and system

Abstract

The application discloses a kind of energy segment active addressing type sub-spot laser processing method and system, it is related to laser processing technical field.The method is in dynamic scanning process, by beam time modulator, laser beam is converted into multiple independent controllable energy segments, and by synchronous controller, the segment that energy is not less than preset effective threshold and is independently grey scale coded is selected as effective control segment;Synchronous controller determines effective control segment number according to spot diameter, modulation frequency and scanning speed, and divides effective control segment into multiple energy groups, adjusts the intensity distribution of each energy group dynamically by feedforward intensity control signal, so that effective energy deposition position occurs controllable deviation, to realize the sub-spot precision processing less than pulse spatial interval.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, and more specifically, to a method and system for energy segment active addressing sub-spot laser processing. Background Technology

[0002] Laser processing technology boasts advantages such as non-contact operation, high energy density, wide applicability to a broad range of materials, and strong processing controllability, and has been widely applied in precision manufacturing, semiconductor processing, optical component manufacturing, display panel manufacturing, and micro / nano structure fabrication. As high-end manufacturing evolves towards larger formats, higher efficiency, and higher precision, industrial processing systems increasingly require sub-micron or even nanometer-level processing positional accuracy under continuous high-speed scanning. However, in existing laser processing systems, a long-standing contradiction exists between achieving large-format processing, high-speed dynamic scanning, and nanometer-level processing accuracy simultaneously. Using high-magnification projection lenses for static or quasi-static exposure can achieve high processing accuracy, but the area covered by a single exposure is typically small. To achieve large-area processing, multiple stitching operations are required, which can easily introduce positional errors. Using a stepper-type processing method allows for high-precision exposure at each stationary position via a precision platform, and larger areas can be processed by moving the platform. However, frequent start-stop cycles reduce processing efficiency, making it difficult to meet the demands of high-throughput industrial manufacturing. When using galvanometers, turntables, linear motors, or roll-to-roll platforms for continuous dynamic scanning, although higher processing efficiency and larger processing area can be achieved, factors such as shaft runout, encoder quantization error, servo following error, thermal drift, and structural vibration in the mechanical system will directly translate into end-processing position error, making it difficult to stably break through the limitations of mechanical positioning accuracy.

[0003] In traditional dynamic scanning laser processing technology, the laser repetition frequency (f) and scanning speed (v) are generally considered to be process parameters affecting processing efficiency and pulse overlap. Existing technologies commonly use concepts such as the number of pulses per spot and pulse overlap rate, primarily to describe the number of pulses or the spatial arrangement of pulses within a unit spot area; these are essentially passive geometric statistics. These parameters only reflect how many pulses cover a certain area, but cannot further describe which pulses actually participate in material modification, nor can they actively control the processing position accuracy. In actual processing, some pulses may fail to contribute effectively due to low energy, uncertain modulation states, or being below the material modification threshold. Simply including these pulses in the number of pulses per spot cannot accurately reflect the system's true accuracy control capability. Furthermore, traditional processing schemes typically bind the final processing position to the mechanical scanning position or the geometric center of the spot; mechanical motion errors are directly transmitted to the processing result, causing processing accuracy to be limited by the limits of the mechanical system.

[0004] Therefore, existing technologies urgently need a new laser processing method and system that can shift the determining factor of processing position accuracy from macroscopic mechanical positioning to microscopic energy deposition control without sacrificing large-format and high-speed dynamic scanning capabilities. By actively controlling the effective energy distribution inside the spot, sub-spot precision processing smaller than the pulse spatial spacing or even smaller than the spot size can be achieved. Summary of the Invention

[0005] This invention aims to solve the problems in traditional dynamic scanning laser processing where the processing position accuracy relies excessively on mechanical positioning accuracy, the number of pulses within the laser spot is only a passive statistical quantity, and the effective energy deposition position within the laser spot cannot be actively controlled.

[0006] To address the above problems, this invention provides an energy segment active addressing sub-spot laser processing method, comprising the following steps: S1: Provide a focused laser beam to form a processing spot on the surface of the workpiece. The diameter of the processing spot in the scanning motion direction is D, and the repetition frequency of the focused laser beam or the equivalent modulation frequency generated after external modulation is f. S2: The focused laser beam is converted into a series of independent and controllable energy segments by a beam time modulator, and a corresponding gray level is assigned to each energy segment by a synchronization controller; S3: The focused laser beam and the workpiece generate a continuous dynamic scanning motion at a scanning speed v, and the real-time scanning position information between the focused laser beam and the workpiece is obtained; S4: The synchronization controller (5) determines the number of candidate energy segments within the processing spot range based on the spot diameter D, the equivalent modulation frequency f, and the scanning speed v, wherein the number of candidate energy segments is floor(D·f / v) or ceil(D·f / v); where floor() represents the floor function, taking the largest integer not greater than the value in parentheses; ceil() represents the floor function, taking the smallest integer not less than the value in parentheses; and among the candidate energy segments, energy segments with energy not lower than a preset effective threshold and independently assigned gray levels are selected as effective control segments to determine the number of effective control segments η_eff, where η_eff≥2; S5: Divide the η_eff effective control segments into K energy groups, where K is an integer greater than or equal to 2, and assign an independent and controllable intensity value to each energy group. The intensity value is taken from the G_eff level effective gray level, where G_eff is an integer greater than 1. S6: During the continuous dynamic scanning motion, the synchronous controller generates a feedforward intensity control signal according to a preset position deviation mapping table, and adjusts the intensity distribution of each energy group in real time through the feedforward intensity control signal, so that the effective energy deposition position in the processing spot is subject to controllable offset, thereby achieving an equivalent processing position accuracy less than the pulse spatial spacing d, where d=v / f.

[0007] The present invention provides an energy segment active addressing sub-spot laser processing method, which, compared with the prior art, has the following beneficial effects, but is not limited to: To address the issues of excessive reliance on mechanical positioning accuracy, passive statistical calculation of pulse count within the laser spot, and inability to actively control the effective energy deposition position within the laser spot in traditional dynamic scanning laser processing, this method addresses these problems. During processing, the laser source outputs a fundamental frequency laser, which, after passing through an optical focusing system, forms a processing spot on the workpiece surface. The diameter of this processing spot in the scanning direction is D. If a pulsed laser source is used, the laser repetition frequency can be used as the modulation frequency f; if a continuous laser source is used, a beam time modulator performs high-speed chopping and grayscale modulation on the continuous laser, thereby forming an equivalent modulation frequency f. The dynamic scanning motion system drives the workpiece or beam to generate continuous relative motion at a scanning speed of v. A position sensor collects the scanning position in real time and feeds it back to the synchronization controller. The synchronization controller calculates the number of effective controllable segments η_eff within the current processing spot range based on D, f, and v, and divides these η_eff effective controllable segments into at least two energy groups. Each energy group is assigned an independently controllable intensity value, which is derived from the calibrated G_eff level effective grayscale. The synchronous controller, based on the deviation between the target position and the actual scanning position in the pattern to be processed, calls the corresponding intensity allocation strategy from the position deviation mapping table, generates a feedforward intensity control signal in real time, and outputs it to the beam time modulator. The beam time modulator adjusts the energy of each energy group according to this feedforward intensity control signal, causing a controllable shift in the effective energy deposition position within the beam spot along the scanning direction. Since this shift is determined by the relative intensities of multiple energy groups, even if the macroscopic beam direction does not undergo high-precision displacement, a subtle movement of the equivalent processing position can be achieved. This method makes the processing position control no longer entirely dependent on the positioning accuracy of the mechanical system, but rather determined by the time modulation accuracy, grayscale resolution, and energy group distribution, thereby achieving sub-spot precision processing smaller than the pulse spatial interval, enabling high-speed dynamic scanning and sub-spot precision control to be realized simultaneously.

[0008] Furthermore, the number of candidate energy segments corresponds to the theoretical number of segments determined according to D·f / v within the processing spot range, and the number of effective controllable segments η_eff is less than or equal to the number of candidate energy segments; the effective controllable segment is a candidate energy segment that satisfies the following conditions: Firstly, the grayscale levels are independently encoded and assigned by the synchronous controller (5); Secondly, the energy is not lower than the preset effective threshold, which is determined based on the material modification threshold of the workpiece (6); Candidate energy segments that do not meet the above conditions are forced to be set to zero or controlled below the preset effective threshold, and are not included in the effective control segment number η_eff.

[0009] Furthermore, when D·f / v is not an integer, the synchronization controller selects floor(D·f / v) or ceil(D·f / v) as the effective number of control segments η_eff at the current moment, based on the current scanning position, target processing accuracy, and energy group configuration method.

[0010] Furthermore, by changing the time modulation mode, different effective control segments η_eff can be obtained under the condition of physical pulse number N=D·f / v within the same light spot. The time modulation mode includes at least one of pulse train duty cycle, energy coding sequence, segment gating mode and grayscale allocation mode.

[0011] Furthermore, the position deviation mapping table is obtained through experimental calibration and is used to establish the correspondence between the target equivalent processing position deviation and the intensity distribution of each energy group, and to compensate for at least one of the process effects such as material ablation threshold nonlinearity, thermal accumulation effect, laser energy fluctuation, scanning speed change and actual spot energy distribution deviation.

[0012] Furthermore, the effective gray level number G_eff is obtained through system calibration. The system calibration includes testing the output linearity, laser energy stability, synchronization control timing accuracy, and effective material response of the beam time modulator at a preset modulation frequency f, and determining the number of intensity levels that can be stably distinguished and can produce repeatable material modification results as G_eff. The theoretical displacement control resolution δx of the method can be expressed as: δx = d / G_eff = (v / f) / G_eff; The actual machining position accuracy δx_actual can be expressed as: δx_actual = δx·C; The dynamic addressing capacity Φ_eff can be expressed as: Φ_eff = η_eff · G_eff; Wherein, C is the process factor, and C≥1. The process factor C is obtained through experimental calibration. The dynamic addressing capacity Φ_eff represents the total number of equivalent processing positions that can be independently resolved within the diameter range of a single processing spot.

[0013] The present invention also provides an energy segment active addressing sub-spot laser processing system for performing the above method, the system comprising: A laser source used to generate fundamental frequency laser light; A beam time modulator is disposed on the output path of the laser source to modulate the fundamental frequency laser into multiple independent and controllable energy segments and to perform grayscale encoding on each energy segment; A dynamic scanning motion system is used to drive a focused laser beam to generate continuous dynamic scanning motion between the laser beam and the workpiece. A position sensor is used to detect the real-time relative position between the focused laser beam and the workpiece, and to feed back real-time scanning position information to the synchronization controller; The synchronization controller is electrically connected to the beam time modulator, the dynamic scanning motion system, and the position sensor, respectively. It is used to select energy segments with energy not lower than a preset effective threshold and independently grayscale encoded as effective control segments. It determines the number of effective control segments η_eff according to the scanning speed v, the spot diameter D, and the modulation frequency f, and generates a feedforward intensity control signal according to a preset position deviation mapping table to adjust the intensity distribution of each energy group, so that the effective energy deposition position in the processing spot produces a controllable shift.

[0014] Furthermore, the synchronization controller includes: The effective fragment filtering module is used to determine whether each energy fragment meets the preset effective threshold, and select the energy fragments that meet the preset effective threshold and are independently grayscale encoded as effective control fragments. The energy group partitioning module is used to divide the η_eff effective regulatory segments into K energy groups; An intensity allocation module is used to determine the target intensity value of each energy group according to the position deviation mapping table. The feedforward control module is used to generate a feedforward intensity control signal based on the target intensity value and output it to the beam time modulator.

[0015] Furthermore, the focused laser beam is a pulsed laser beam, or an equivalent pulsed laser beam formed by chopping a continuous laser beam through the beam time modulator; The beam time modulator includes at least one of an acousto-optic modulator, an electro-optic modulator, a spatial light modulator, a digital micromirror device, and an in-laser modulation module; The synchronization controller updates the feedforward intensity control signal at a frequency of not less than 1MHz to achieve independent grayscale encoding of each energy segment.

[0016] Furthermore, when the dynamic scanning motion system performs variable speed scanning, the synchronization controller calculates the instantaneous scanning speed based on the real-time scanning position information fed back by the position sensor, and dynamically updates η_eff, the energy group division method, and the intensity value of each energy group; the system also includes a multi-focus generation module, which is used to expand the focused laser beam into M parallel focuses, where M is an integer greater than or equal to 2, and each parallel focus corresponds to an independent energy segment control channel. Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of an energy segment active addressing sub-spot laser processing method according to an embodiment of the present invention; Figure 2 This is a structural block diagram of an energy segment active addressing sub-spot laser processing system according to an embodiment of the present invention; Figure 3 This is a schematic diagram of an effective control segment in an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the differences in G_eff among different effective regulatory segments in an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the relationship between the effective number of gray levels G_eff and the material damage threshold in an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the dynamic addressing capacity formed by the linkage modulation of the effective number of control segments η_eff and the effective number of gray levels G_eff in an embodiment of the present invention. Figure 7 This is a schematic diagram illustrating the detection of processing traces and their structural dimensions of a single-focused light spot in an embodiment of the present invention. Figure 8 This is a schematic diagram illustrating the detection of sub-spot dynamic control of structural scale after active addressing of energy segments in an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 1. Laser source; 2. Beam time modulator; 3. Dynamic scanning motion system; 4. Position sensor; 5. Synchronization controller; 51. Effective segment selection module; 52. Energy group division module; 53. Intensity distribution module; 54. Feedforward control module; 6. Workpiece. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, specific embodiments of this application are described clearly and completely below with reference to the accompanying drawings. It should be understood that the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments described in this application without creative effort will fall within the scope of protection of this application.

[0020] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the specification of this application is for the purpose of describing specific embodiments only and is not intended to limit this application; the terms "comprising," "including," "having," "containing," "comprise," etc., in the specification, claims, and accompanying drawings of this application are open-ended terms, indicating that a method comprises one or more steps, or an apparatus comprises one or more elements, but do not exclude the inclusion of other steps or elements. The terms "first," "second," etc., in the specification, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or primary / secondary relationship. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0021] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0022] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0024] See Figure 1 , Figure 3 , Figure 4 , Figure 5 and Figure 6 An embodiment of the present invention provides an energy segment active addressing sub-spot laser processing method, comprising the following steps: S1: Provide a focused laser beam to form a processing spot on the surface of workpiece 6. The diameter of the processing spot in the scanning motion direction is D, and the repetition frequency of the focused laser beam or the equivalent modulation frequency generated after external modulation is f. S2: The focused laser beam is converted into a series of independent and controllable energy segments by the beam time modulator 2, and the corresponding gray level is assigned to each energy segment by the synchronization controller 5. S3: The focused laser beam and the workpiece 6 generate a continuous dynamic scanning motion at a scanning speed v, and the real-time scanning position information between the focused laser beam and the workpiece 6 is obtained; S4: The synchronization controller 5 determines the number of candidate energy segments within the processing spot range based on the spot diameter D, the equivalent modulation frequency f, and the scanning speed v, wherein the number of candidate energy segments is floor(D·f / v) or ceil(D·f / v); where floor() represents a floor function that rounds down to the largest integer not greater than the value in parentheses; ceil() represents a floor function that rounds up to the smallest integer not less than the value in parentheses; and among the candidate energy segments, energy segments with energy not lower than a preset effective threshold and independently assigned gray levels are selected as effective control segments to determine the number of effective control segments η_eff, where η_eff≥2; S5: Divide the η_eff effective control segments into K energy groups, where K is an integer greater than or equal to 2, and assign an independent and controllable intensity value to each energy group. The intensity value is taken from the G_eff level effective gray level, where G_eff is an integer greater than 1. S6: During the continuous dynamic scanning motion, the synchronous controller 5 generates a feedforward intensity control signal according to a preset position deviation mapping table, and adjusts the intensity distribution of each energy group in real time through the feedforward intensity control signal, so that the effective energy deposition position in the processing spot produces a controllable offset, thereby achieving an equivalent processing position accuracy less than the pulse spatial spacing d, where d=v / f.

[0025] In this embodiment, addressing the problems of traditional dynamic scanning laser processing where the processing position accuracy relies excessively on mechanical positioning accuracy, the number of pulses within the laser spot is merely a passive statistical quantity, and the inability to actively control the effective energy deposition position within the laser spot, the laser source 1 outputs a fundamental frequency laser during processing. This fundamental frequency laser, after passing through an optical focusing system, forms a processing spot on the surface of the workpiece 6. The diameter of this processing spot in the scanning direction is D. If a pulsed laser source 1 is used, the laser repetition frequency can be used as the modulation frequency f; if a continuous laser source 1 is used, the continuous laser is subjected to high-speed chopping and grayscale modulation by a beam time modulator 2, thereby forming an equivalent modulation frequency f. The dynamic scanning motion system 3 drives the workpiece 6 or the laser beam to generate continuous relative motion at a scanning speed of v. The position sensor 4 collects the scanning position in real time and feeds it back to the synchronization controller 5. The synchronization controller 5 calculates the number of effective controllable segments η_eff within the current processing spot range based on D, f, and v, and divides the η_eff effective controllable segments into at least two energy groups. Each energy group is assigned an independently controllable intensity value, which is taken from the calibrated G_eff level effective grayscale. The synchronous controller 5, based on the deviation between the target position and the actual scanning position in the pattern to be processed, calls the corresponding intensity allocation strategy from the position deviation mapping table, generates a feedforward intensity control signal in real time, and outputs it to the beam time modulator 2. The beam time modulator 2 adjusts the energy of each energy group according to this feedforward intensity control signal, causing a controllable shift in the effective energy deposition position within the beam spot along the scanning direction. Since this shift is determined by the relative intensities of multiple energy groups, even if the macroscopic beam direction does not undergo high-precision displacement, a subtle movement of the equivalent processing position can be achieved. This method makes the processing position control no longer entirely dependent on the positioning accuracy of the mechanical system, but rather determined by the time modulation accuracy, grayscale resolution, and energy group distribution, thereby achieving sub-spot precision processing smaller than the pulse spatial interval, enabling simultaneous high-speed dynamic scanning and sub-spot precision control.

[0026] Optionally, the number of candidate energy segments corresponds to the theoretical number of segments determined according to D·f / v within the processing spot range, and the number of effective controllable segments η_eff is less than or equal to the number of candidate energy segments; the effective controllable segment is a candidate energy segment that meets the following conditions: first, it is independently encoded and assigned a grayscale level by the synchronous controller 5; second, its energy is not lower than the preset effective threshold, which is determined according to the material modification threshold of the workpiece 6; wherein, candidate energy segments that do not meet the above conditions are forcibly set to zero or controlled below the preset effective threshold, and are not included in the number of effective controllable segments η_eff.

[0027] This embodiment explains the difference between effective control segments and the number of physical pulses N within the light spot. The traditional number of physical pulses N within the light spot is calculated using D·f / v, which only represents the number of pulses counted by spatial spacing within the processing light spot diameter; this is a passive geometric statistical method. This statistical result may include pulses that are not activated, low-energy pulses, pulses not independently grayscale encoded, and pulses below the material modification threshold. Although these pulses physically fall within the light spot range, they cannot stably participate in material modification, nor can they be used to precisely control the processing position. In this invention, η_eff only counts effective control segments. Each segment included in η_eff must simultaneously meet two conditions: first, it must be independently encoded by the synchronization controller 5 and assigned a specific grayscale level; second, the energy of the segment must be higher than the minimum effective dose determined by the material modification threshold. Please refer to [link to relevant documentation]. Figure 5 The synchronous controller 5 first sets a preset effective threshold based on the material damage threshold of the material to be processed. This material damage threshold can be obtained through pre-experimentation. For example, under the same laser wavelength, pulse width, spot size, and scanning speed, the laser energy of a single energy segment is gradually increased, and the surface of the workpiece 6 is checked for stable processing marks, morphological changes, ablation pits, phase transition regions, or changes in optical properties. When a certain energy level begins to produce repeatable material changes, the laser energy or energy density corresponding to that energy level can be used as a reference value for the material damage threshold. For segments that do not meet the above conditions, the synchronous controller 5 forces them to zero or controls them below the preset effective threshold, so that they do not participate in effective energy regulation. Through this screening, the present invention transforms traditional passive pulse statistics into an effective spatial addressing structure with an entry threshold. Even under the same D, f, and v conditions, different η_eff can be obtained by changing the pulse train duty cycle, energy encoding sequence, segment gating method, or grayscale allocation method, thereby obtaining different precision control capabilities.

[0028] Optional, please refer to Figure 3When D·f / v is not an integer, the synchronization controller 5 selects floor(D·f / v) or ceil(D·f / v) as the effective number of control segments η_eff at the current moment, based on the current scanning position, target processing accuracy, and energy group configuration method.

[0029] This embodiment explains how η_eff is determined when D·f / v is a non-integer. In actual dynamic scanning, the spot diameter D, modulation frequency f, and scanning speed v are usually not exactly integers; therefore, D·f / v may be a non-integer. For example, when D·f / v equals 10.05, it indicates that the processed spot diameter contains approximately 10.05 segments arranged spatially. In this case, the synchronization controller 5 selects to round down or up based on the current process requirements. Here, floor() represents the rounding down function, and ceil() represents the rounding up function; floor(D·f / v) is the largest integer not greater than D·f / v, and ceil(D·f / v) is the smallest integer not less than D·f / v. In the example where D·f / v equals 10.05, floor(D·f / v) is 10, and ceil(D·f / v) is 11. If the system prioritizes the stability between energy clusters and the repeatability of segments, floor (D·f / v) can be selected as η_eff; if the system needs to ensure the continuity of energy coverage at boundary positions, ceil (D·f / v) can be selected as η_eff. After determining η_eff, the synchronous controller 5 processes segments not included in η_eff. These segments can be forcibly set to zero to prevent them from depositing effective energy into the workpiece 6, or they can be controlled below a preset effective threshold to prevent them from making repeatable material modification contributions. This processing method avoids edge segments being in a semi-effective state, which leads to unstable effective energy distribution. For variable speed scanning or curve scanning, the value of D·f / v changes with the instantaneous speed. The synchronous controller 5 can recalculate the current η_eff in each control cycle and dynamically select floor or ceil according to the target processing position and energy cluster layout, so that the number of effectively controlled segments is always consistent with the current scanning state.

[0030] Optionally, by changing the time modulation mode, different effective control segments η_eff can be obtained under the condition of physical pulse number N=D·f / v within the same light spot. The time modulation mode includes at least one of pulse train duty cycle, energy coding sequence, segment gating mode and grayscale allocation mode.

[0031] This embodiment describes how different η_eff values ​​are obtained by changing the time modulation mode. In a conventional parameter system, when the spot diameter D, modulation frequency f, and scanning speed v are fixed, the number of physical pulses N = D·f / v within the spot is also fixed. However, η_eff in this invention is not equivalent to N, but depends on which segments are independently encoded and reach the effective energy threshold. Therefore, under the same condition of N, different η_eff values ​​can still be obtained by changing the time modulation mode. For example, the synchronization controller 5 can change the pulse train duty cycle, so that some pulses are in a closed state or below the threshold state, thereby reducing η_eff; it can also change the energy encoding sequence, so that the originally low-energy segments are raised above the threshold, thereby increasing η_eff. The synchronization controller 5 can also adjust the segment selection method, excluding unstable segments at the edge of the spot from the effective control segments, or combine multiple segments into an energy group with a clear spatial weight through grayscale allocation. In these ways, the system can adjust the spatial addressing structure without changing the mechanical scanning speed and laser frequency. This embodiment demonstrates that η_eff has an active control attribute, rather than a simple pulse number count.

[0032] Optionally, the position deviation mapping table is obtained through experimental calibration and is used to establish the correspondence between the target equivalent processing position deviation and the intensity distribution of each energy group, and to compensate for at least one of the process effects such as material ablation threshold nonlinearity, thermal accumulation effect, laser energy fluctuation, scanning speed change and actual energy distribution deviation of the spot.

[0033] This embodiment describes the establishment and use of the position deviation mapping table. Because different materials exhibit nonlinear characteristics in their absorption, melting, vaporization, ablation, or modification processes of laser energy, the theoretical effective energy deposition location does not always perfectly coincide with the actual material modification center. Therefore, before formal processing, a position deviation mapping table can be established through experimental calibration. During calibration, the material to be processed, laser wavelength, pulse width, modulation frequency, scanning speed, spot diameter, and environmental conditions are first selected. Then, multiple sets of energy group intensity distributions are set, for example, changing the intensity ratio between the left, middle, and right groups, and test lines, test points, or periodic microstructures are processed respectively. Afterwards, scanning electron microscopes, atomic force microscopes, white light interferometers, profilometers, or optical microscopy measurement systems are used to detect the processing results, obtaining the offset of the actual material modification center relative to the geometric center of the spot or reference trajectory. The synchronous controller 5 records each set of intensity distributions and corresponding offsets as mapping data, and a position deviation mapping table can be formed through interpolation, fitting, or table lookup. During actual processing, the synchronous controller 5 searches for or calculates the required energy group intensity combination from the mapping table based on the deviation between the target position and the current scanning position in the pattern to be processed, and generates a feedforward intensity control signal. This mapping table can compensate for the effects of nonlinearity of material ablation threshold, thermal accumulation effect, laser energy fluctuation, imperfect actual energy distribution of the laser spot, and velocity variation, so that the control result is consistent with the actual processing result.

[0034] Optionally, the effective number of gray levels G_eff is obtained through system calibration. The system calibration includes testing the output linearity, laser energy stability, synchronization control timing accuracy, and effective material response of the beam time modulator 2 at a preset modulation frequency f, and determining the number of intensity levels that can be stably distinguished and can produce repeatable material modification results as G_eff. The theoretical displacement control resolution δx of the method can be expressed as: δx = d / G_eff = (v / f) / G_eff; The actual machining position accuracy δx_actual can be expressed as: δx_actual = δx·C; The dynamic addressing capacity Φ_eff can be expressed as: Φ_eff = η_eff · G_eff; Wherein, C is the process factor, and C≥1. The process factor C is obtained through experimental calibration. The dynamic addressing capacity Φ_eff represents the total number of equivalent processing positions that can be independently resolved within the diameter range of a single processing spot.

[0035] In this embodiment, the effective number of gray levels G_eff, theoretical displacement control resolution, actual processing accuracy, and dynamic addressing capacity are explained. G_eff is not the nominal number of gray levels of the modulator, but rather the number of effective intensity levels that can be stably distinguished, stably output, and cause repeatable material responses under the current operating conditions. To determine G_eff, multiple candidate gray values ​​can be input to the beam time modulator 2 at a preset modulation frequency f, and the corresponding output energy can be measured using a high-speed photodetector, energy meter, or power meter to obtain the relationship curve between the input gray level and the output energy. Subsequently, stability and monotonicity analysis is performed on this relationship curve, eliminating gray levels with unstable output energy, indistinguishable adjacent levels, or those in the modulator saturation region. Further, processing verification is performed on actual materials to test whether different candidate gray levels can produce repeatable and distinguishable material modification results. If some gray levels differ in optical measurements, but the center, depth, width, or degree of modification of the processing trace cannot be stably distinguished, these levels are not included in G_eff. The pulse spatial spacing d satisfies d=v / f, the theoretical displacement control resolution δx satisfies δx=d / G_eff, the actual machining position accuracy δx_actual satisfies δx_actual=δx·C, and the dynamic addressing capacity Φ_eff satisfies Φ_eff=η_eff·G_eff. Using the above model, system designers can reverse-engineer the modulation frequency, scanning speed, number of gray levels, and energy group partitioning method according to the machining accuracy target.

[0036] See Figure 2 This invention also provides an energy segment active addressing sub-spot laser processing system for performing the above method, the system specifically comprising: The system comprises a laser source 1, a beam time modulator 2, a dynamic scanning motion system 3, a position sensor 4, and a synchronization controller 5. The laser source 1 generates a fundamental frequency laser, which can be either pulsed or continuous. The beam time modulator 2, positioned along the laser propagation path, receives the feedforward intensity control signal output from the synchronization controller 5 and performs time segmentation, gating, and grayscale modulation of the laser beam based on this signal. The dynamic scanning motion system 3 generates relative scanning motion between the focused laser beam and the workpiece 6. It can drive the workpiece 6 to move, drive beam scanning, or combine beam scanning with workpiece 6 movement. The position sensor 4 detects the scanning position in real time and transmits the position information to the synchronization controller 5. The synchronization controller 5, as the core control unit of the system, calculates the scanning speed based on the position information and determines η_eff by combining the spot diameter D and modulation frequency f. Then, the synchronization controller 5 obtains the target intensity value of each energy group according to the position deviation mapping table and outputs the feedforward intensity control signal to the beam time modulator 2. This system achieves large-format processing through mechanical scanning, energy segment addressing through time modulation, and effective energy deposition position shifting through energy group intensity allocation, thereby combining macroscopic motion with microscopic energy control to achieve sub-spot processing under high-speed dynamic scanning conditions.

[0037] Optionally, the synchronization controller 5 includes: an effective segment screening module 51, used to determine whether each energy segment meets a preset effective threshold, and select energy segments that meet the preset effective threshold and are independently grayscale encoded as effective control segments; an energy group division module 52, used to divide η_eff effective control segments into K energy groups; an intensity allocation module 53, used to determine the target intensity value of each energy group according to the position deviation mapping table; and a feedforward control module 54, used to generate a feedforward intensity control signal according to the target intensity value and output it to the beam time modulator 2.

[0038] In this embodiment, the module structure of the synchronization controller 5 is described. The synchronization controller 5 includes an effective segment selection module 51, an energy group division module 52, an intensity allocation module 53, and a feedforward control module 54. The effective segment selection module 51 receives the target grayscale level and actual energy state of each energy segment and determines whether it reaches a preset effective threshold. For segments that reach the threshold and have independent coding, the module marks them as effective control segments; for segments below the threshold or without independent coding, the module marks them as invalid segments. The energy group division module 52 divides the effective control segments into K energy groups according to the current η_eff and the target processing mode. This division can be performed in spatial order, such as left group, middle group, and right group, or a non-uniform grouping method can be used according to the processing pattern requirements. The intensity allocation module 53 queries the target intensity value of each energy group from the position deviation mapping table according to the target position deviation and quantizes the intensity value in combination with the current G_eff. The feedforward control module 54 generates a control waveform, digital command, or analog voltage signal that matches the beam time modulator 2 based on the intensity allocation result. The above modules work together to enable the synchronous controller 5 to complete the selection of effective segments, construction of spatial addressing structure, allocation of intensity value and output of modulation signal in real time during dynamic scanning.

[0039] Optionally, the focused laser beam is a pulsed laser beam, or an equivalent pulsed laser beam formed by chopping a continuous laser beam by the beam time modulator 2; the beam time modulator 2 includes at least one of an acousto-optic modulator, an electro-optic modulator, a spatial light modulator, a digital micromirror device, and an in-laser modulation module; the synchronization controller 5 updates the feedforward intensity control signal at a frequency of not less than 1 MHz to achieve independent grayscale encoding of each energy segment.

[0040] This embodiment describes the adaptation methods for pulsed lasers, continuous lasers, and beam time modulator 2. When using pulsed laser source 1, each pulse output by laser source 1 can be used as a basic energy segment. Beam time modulator 2 gates and modulates the grayscale of each pulse to obtain an independent intensity value. Synchronization controller 5 performs pulse-by-pulse encoding based on pulse trigger signal and position feedback signal, thereby forming an effective control segment that can be used for energy regulation. When using continuous laser source 1, continuous laser itself does not have a natural pulse interval. Therefore, it can be divided into a series of equivalent pulse energy segments by high-speed chopping using an acousto-optic modulator, electro-optic modulator, or an in-laser modulation module. The modulation frequency of this equivalent pulse sequence is f. Beam time modulator 2 can be an acousto-optic modulator, electro-optic modulator, spatial light modulator, digital micromirror device, or in-laser modulation module. Acousto-optic modulators are suitable for pulse gating and grayscale modulation, electro-optic modulators are suitable for higher frequency energy segment modulation, spatial light modulators can be used to form multi-focal or complex energy distributions, digital micromirror devices can be used for patterned energy distribution, and the modulation module within the laser can generate controllable energy segments by controlling the laser drive current, pump energy, or intracavity modulation unit. Synchronization controller 5 can be implemented using an FPGA, real-time controller, high-speed DSP, or dedicated timing control chip, and updates the feedforward intensity control signal at a frequency of not less than 1MHz.

[0041] Optionally, when the dynamic scanning motion system 3 performs variable speed scanning, the synchronization controller 5 calculates the instantaneous scanning speed based on the real-time scanning position information fed back by the position sensor 4, and dynamically updates η_eff, the energy group division method, and the intensity value of each energy group; the system also includes a multi-focus generation module, which is used to expand the focused laser beam into M parallel focuses, where M is an integer greater than or equal to 2, and each parallel focus corresponds to an independent energy segment control channel.

[0042] In this embodiment, the dynamic scanning motion system 3 includes at least one of a rotary table scanning platform, a galvanometer scanning system, an air-bearing linear motor platform, a linear motor platform, and a roll-to-roll scanning platform. In actual industrial processing, the dynamic scanning motion system 3 may need to perform variable speed motion according to the pattern shape, trajectory curvature, acceleration / deceleration sections, or material heat accumulation. If the scanning speed v changes, the values ​​of the pulse spatial spacing d=v / f and D·f / v also change accordingly. To ensure stable sub-spot accuracy, the synchronization controller 5 receives position information fed back by the position sensor 4 in real time and calculates the instantaneous scanning speed in each control cycle. The synchronization controller 5 recalculates η_eff based on the instantaneous scanning speed and adjusts the energy group division method and the intensity value of each energy group. If the speed increases, the number of usable segments within a unit spot area decreases, and the synchronization controller 5 can reduce the number of segments within an energy group or increase the modulation frequency; if the speed decreases, the number of usable segments within a unit spot area increases, and the synchronization controller 5 can reallocate segments to maintain stable energy distribution. To improve industrial processing throughput, the system can also be equipped with a multi-focus generation module to expand a single laser beam into M parallel focuses. The multi-focus generation module can employ spatial light modulators, diffractive optical elements, microlens arrays, beam splitters, or combinations thereof. Each parallel focus corresponds to an independent or quasi-independent energy segment control channel. The synchronous controller 5 calculates the corresponding η_eff, energy group division method, and intensity allocation strategy based on the local scanning position and target pattern of each focus, thereby improving processing throughput while maintaining sub-spot processing accuracy.

[0043] Specific experimental examples Experiment Example 1: Pulsed Laser, AOM Modulation and Rotary Scanning Machining System Configuration: A picosecond pulsed laser is used as the laser source 1, with a wavelength of 1064nm and a repetition frequency of 10MHz. An acousto-optic modulator is used as the beam time modulator 2, and the effective grayscale level G_eff is calibrated to be 16 levels within a stable modulation bandwidth. The dynamic scanning motion system 3 uses a rotating turntable scanning platform with a radius of 750mm and a rotation speed of 95rpm, corresponding to a linear velocity of approximately 7.5m / s at the processing position. The optical system focuses the laser onto the surface of the workpiece 6, with a focused spot diameter of 20μm, and an effective spot diameter D of 7.5μm in the scanning motion direction. The synchronous controller 5 uses an FPGA to implement pulse-by-pulse intensity encoding and updates the intensity control signal at a frequency of 10MHz.

[0044] Process and Parameters: During processing, the pulse spatial spacing d = v / f, approximately 746 nm. The number of physical pulses within the spot area N = D / d, approximately 10.05. The synchronization controller 5 sets a preset effective threshold, considering pulses with intensity 10% lower than the maximum intensity as invalid segments and not counting them as effective control segments. Therefore, the number of effective control segments η_eff available at each processing moment is 10. The synchronization controller 5 divides these 10 effective control segments into multiple energy groups and performs intensity control on each energy group separately.

[0045] Verification Experiment: During test processing on the surface of glass workpiece 6, the energy cluster intensity distribution was set, while keeping the laser power, scanning speed, modulation frequency, and focal point position constant. The center position and dimensions of the processed structure were measured using a scanning electron microscope. The measurement results are as follows: Figure 7 and Figure 8 As shown.

[0046] Test results show that, with a pulse spatial spacing of approximately 746 nm, microstructures with a scale of about 500 nm can be obtained, proving that sub-grid control smaller than the pulse spatial spacing can be achieved through energy group intensity allocation. Based on calculations using δx=d / G_eff, the theoretical displacement control resolution is approximately 46.63 nm; after considering material response and system noise calibration, the actual offset control resolution can be better than 100 nm. This experiment demonstrates that the system can achieve sub-micron level position control far exceeding mechanical positioning accuracy while maintaining a high-speed dynamic scanning speed of 7.5 m / s.

[0047] Experiment Example 2: Continuous Laser, AOM Chopper and Linear Motor Variable Speed ​​Scanning Machining A 532nm continuous-wave laser is used as the laser source 1, and an acousto-optic modulator is used to chop and modulate the continuous laser at a frequency of 50MHz to form an equivalent energy segment sequence. The dynamic scanning motion system 3 uses an air-bearing linear motor platform, and the scanning speed varies from 100mm / s to 500mm / s. The position sensor 4 uses a grating ruler to provide real-time feedback of the scanning position to the synchronous controller 5. The synchronous controller 5 calculates the instantaneous scanning speed based on the position feedback and dynamically calculates η_eff based on the instantaneous speed.

[0048] During variable-speed scanning, if the platform is in the acceleration phase, the synchronous controller 5 detects a gradual increase in the pulse spatial spacing and updates the energy group division method in real time to ensure that the number of effective control segments at each moment matches the current spot coverage state. If the platform is in the deceleration phase, the synchronous controller 5 redistributes the energy groups according to the increased number of segments within the spot and calls the position deviation mapping table for the corresponding speed range. Experimental results show that this method can maintain the stability of the center position of the processed lines and the spacing of microstructures under variable-speed scanning conditions, avoiding energy deposition position drift due to speed changes. This experiment demonstrates that the present invention is not only applicable to fixed-speed scanning but also to variable-speed trajectories commonly encountered in industrial processing.

[0049] Experiment Example 3: Multifocal Parallel Sub-spot Processing A spatial light modulator is used as a multi-focus generation module to expand a single laser beam into a 1×8 focal linear array. Each focal point corresponds to an independent acousto-optic modulation channel or an independently controllable grayscale encoding region. A dynamic scanning motion system 3 drives the workpiece 6 to move continuously relative to the focal linear array. A synchronization controller 5 establishes an independent η_eff calculation unit and an energy group intensity allocation unit for each focal point, and calls the corresponding position deviation mapping table according to the location of each focal point.

[0050] During processing, eight focal points act synchronously on the surface of workpiece 6. Within each focal point, the effective energy deposition position is controllably shifted through effective segment selection and energy group intensity distribution. Compared with single-focal-point processing, the multi-focal linear array can significantly improve processing throughput while maintaining the sub-spot processing accuracy of a single focal point. This experiment demonstrates that the present invention can be extended to multi-channel, multi-focal-point, and large-area parallel processing scenarios, exhibiting good industrial scalability.

[0051] As can be seen from the above experimental examples one to three, the present invention does not simply rely on improving the positioning accuracy of the mechanical scanning system to improve the processing accuracy. Instead, it achieves equivalent processing position control that is smaller than the pulse spatial spacing by screening, encoding, grouping and intensity regulating the energy segments within the light spot during dynamic scanning.

[0052] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for active addressing sub-spot laser processing of energy segments, characterized in that, Includes the following steps: S1: Provide a focused laser beam to form a processing spot on the surface of the workpiece (6). The diameter of the processing spot in the scanning motion direction is D, and the repetition frequency of the focused laser beam or the equivalent modulation frequency generated after external modulation is f. S2: The focused laser beam is converted into a series of independent and controllable energy segments by the beam time modulator (2), and the corresponding gray level is assigned to each energy segment by the synchronization controller (5); S3: The focused laser beam and the workpiece (6) generate a continuous dynamic scanning motion at a scanning speed v, and the real-time scanning position information between the focused laser beam and the workpiece (6) is obtained; S4: The synchronization controller (5) determines the number of candidate energy segments within the processing spot range based on the spot diameter D, the equivalent modulation frequency f, and the scanning speed v, wherein the number of candidate energy segments is floor(D·f / v) or ceil(D·f / v); where floor() represents the floor function, taking the largest integer not greater than the value in parentheses; ceil() represents the floor function, taking the smallest integer not less than the value in parentheses; and among the candidate energy segments, energy segments with energy not lower than a preset effective threshold and independently assigned gray levels are selected as effective control segments to determine the number of effective control segments η_eff, where η_eff≥2; S5: Divide the η_eff effective control segments into K energy groups, where K is an integer greater than or equal to 2, and assign an independent and controllable intensity value to each energy group. The intensity value is taken from the G_eff level effective gray level, where G_eff is an integer greater than 1. S6: During the continuous dynamic scanning motion, the synchronous controller (5) generates a feedforward intensity control signal according to the preset position deviation mapping table, and adjusts the intensity distribution of each energy group in real time through the feedforward intensity control signal, so that the effective energy deposition position in the processing spot produces a controllable offset, thereby achieving an equivalent processing position accuracy less than the pulse space interval d, where d=v / f.

2. The energy segment active addressing sub-spot laser processing method according to claim 1, characterized in that, The number of candidate energy segments corresponds to the theoretical number of segments within the processing spot range determined according to D·f / v, and the number of effective controllable segments η_eff is less than or equal to the number of candidate energy segments; the effective controllable segments are candidate energy segments that satisfy the following conditions: Firstly, the grayscale levels are independently encoded and assigned by the synchronous controller (5); Secondly, the energy is not lower than the preset effective threshold, which is determined based on the material modification threshold of the workpiece (6); Candidate energy segments that do not meet the above conditions are forced to be set to zero or controlled below the preset effective threshold, and are not included in the effective control segment number η_eff.

3. The energy segment active addressing sub-spot laser processing method according to claim 1, characterized in that, When D·f / v is not an integer, the synchronization controller (5) selects floor(D·f / v) or ceil(D·f / v) as the effective number of control segments η_eff at the current moment according to the current scanning position, target processing accuracy and energy group configuration method.

4. The energy segment active addressing sub-spot laser processing method according to claim 1, characterized in that, By changing the time modulation mode, different effective control segment numbers η_eff can be obtained under the same physical pulse number N=D·f / v condition within the same light spot. The time modulation mode includes at least one of pulse train duty cycle, energy coding sequence, segment gating mode and grayscale allocation mode.

5. The energy segment active addressing sub-spot laser processing method according to claim 1, characterized in that, The position deviation mapping table is obtained through experimental calibration and is used to establish the correspondence between the target equivalent processing position deviation and the intensity distribution of each energy group. It is also used to compensate for at least one of the process effects, such as nonlinearity of material ablation threshold, thermal accumulation effect, laser energy fluctuation, scanning speed change and deviation of actual spot energy distribution.

6. The energy segment active addressing sub-spot laser processing method according to claim 1, characterized in that, The effective gray level number G_eff is obtained through system calibration. The system calibration includes testing the output linearity, laser energy stability, synchronization control timing accuracy and material effective response of the beam time modulator (2) at a preset modulation frequency f, and determining the number of intensity levels that can be stably distinguished and can produce repeatable material modification results as G_eff. The theoretical displacement control resolution δx of the method can be expressed as: δx = d / G_eff = (v / f) / G_eff; The actual machining position accuracy δx_actual can be expressed as: δx_actual = δx·C; The dynamic addressing capacity Φ_eff can be expressed as: Φ_eff = η_eff · G_eff; Wherein, C is the process factor, and C≥1. The process factor C is obtained through experimental calibration. The dynamic addressing capacity Φ_eff represents the total number of equivalent processing positions that can be independently resolved within the diameter range of a single processing spot.

7. A sub-spot laser processing system with active energy segment addressing, characterized in that, The system for performing the method according to any one of claims 1 to 6, the system comprising: Laser source (1), used to generate fundamental frequency laser; A beam time modulator (2) is disposed on the light output path of the laser source (1) and is used to modulate the fundamental frequency laser into multiple independent and controllable energy segments and to perform grayscale encoding on each energy segment. The dynamic scanning motion system (3) is used to drive the focused laser beam to generate continuous dynamic scanning motion between the workpiece (6); The position sensor (4) is used to detect the real-time relative position between the focused laser beam and the workpiece (6) and to feed back the real-time scanning position information to the synchronization controller (5); The synchronization controller (5) is electrically connected to the beam time modulator (2), the dynamic scanning motion system (3) and the position sensor (4) respectively. It is used to select energy segments with energy not lower than a preset effective threshold and independently grayscale encoded as effective control segments. It determines the number of effective control segments η_eff according to the scanning speed v, the spot diameter D and the modulation frequency f, and generates a feedforward intensity control signal according to the preset position deviation mapping table to adjust the intensity distribution of each energy group so that the effective energy deposition position in the processing spot is controllably shifted.

8. The energy segment active addressing sub-spot laser processing system according to claim 7, characterized in that, The synchronization controller (5) includes: The effective segment filtering module (51) is used to determine whether each energy segment meets the preset effective threshold, and select the energy segments that meet the preset effective threshold and are independently grayscale encoded as effective control segments; The energy group partitioning module (52) is used to divide the η_eff effective regulatory segments into K energy groups; The intensity allocation module (53) is used to determine the target intensity value of each energy group according to the position deviation mapping table. The feedforward control module (54) is used to generate a feedforward intensity control signal based on the target intensity value and output it to the beam time modulator (2).

9. The energy segment active addressing sub-spot laser processing system according to claim 7, characterized in that, The focused laser beam is a pulsed laser beam, or an equivalent pulsed laser beam formed by chopping a continuous laser beam through the beam time modulator (2); The beam time modulator (2) includes at least one of an acousto-optic modulator, an electro-optic modulator, a spatial light modulator, a digital micromirror device, and a modulation module within a laser. The synchronization controller (5) updates the feedforward intensity control signal at a frequency of not less than 1 MHz to achieve independent grayscale encoding of each energy segment.

10. The energy segment active addressing sub-spot laser processing system according to claim 7, characterized in that, When the dynamic scanning motion system (3) performs variable speed scanning, the synchronization controller (5) calculates the instantaneous scanning speed based on the real-time scanning position information fed back by the position sensor (4), and dynamically updates η_eff, the energy group division method and the intensity value of each energy group; the system also includes a multi-focus generation module, which is used to expand the focused laser beam into M parallel focuses, where M is an integer greater than or equal to 2, and each parallel focus corresponds to an independent energy segment control channel.

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