Beam shaping method and beam shaping device

Abstract

The application belongs to the technical field of laser application, and particularly relates to a light beam shaping method and a light beam shaping device. The light beam shaping method comprises the following steps: expanding and collimating a Gaussian light beam through a variable expansion collimator; after collimation, the Gaussian light beam is vertically injected into a light beam shaper with a pre-alignment mark on the light beam shaper as a target; a light spot analyzer is arranged in the transmission direction of the light path, and a light spot image, an X-axis energy curve and a Y-axis energy curve are obtained through the light spot analyzer; the magnification of the variable expansion collimator and / or the position of the light beam shaper in the X-axis and Y-axis directions are adjusted; the normal line from the center of the light spot to the corresponding axis is taken as a symmetry axis, and when the difference between any two symmetric points is less than a preset value, the adjustment is completed. In the application, the magnification of the variable expansion collimator is adjusted according to the light spot image, the incident light spot requirement of the light beam shaper is met, the position of the light beam shaper is adjusted according to the X-axis energy curve and the Y-axis energy curve, a flat-top light spot with uniform energy distribution is obtained, and the shaping is completed.

Description

Technical Field

[0001] This invention belongs to the field of laser application technology, and in particular relates to a beam shaping method and a beam shaping device. Background Technology

[0002] Generally, the laser beam output is a Gaussian beam, and the cross-section of the Gaussian beam is distributed in a Gaussian function. As the requirements for laser processing effect increase, the inventors have found that if the Gaussian beam is directly emitted for processing, the uneven distribution of Gaussian light energy during the processing will cause the processed material to be heated unevenly in the area irradiated by the light spot, which will affect the processing effect. Therefore, the problem in the above scenario needs to be solved. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a beam shaping method and a beam shaping device to address the problem of uneven heating of the laser spot irradiation area during existing laser processing of material surfaces, which affects the processing effect.

[0004] To address the aforementioned technical problems, in one aspect, embodiments of the present invention provide a beam shaping method, comprising:

[0005] The Gaussian beam emitted by the laser is expanded and collimated using a variable magnification beam expander.

[0006] Using the pre-alignment mark on the beam shaper as the target, the expanded and collimated Gaussian beam is vertically injected into the beam shaper;

[0007] A beam analyzer based on the transmission direction of the optical path projects a Gaussian beam after passing through the beam shaper onto the beam analyzer, and obtains the image of the beam spot, the X-axis energy curve and the Y-axis energy curve through the beam analyzer;

[0008] Adjust the magnification of the variable magnification beam expander and / or the position of the beam shaper in the X and Y axis directions;

[0009] Using the normal from the center of the light spot to the corresponding axis as the axis of symmetry, when the difference between any two symmetrical points on the X-axis energy curve and the Y-axis energy curve is less than a first preset value, and the distance between the energy value at the highest point and the energy value at the lowest point is less than a second preset value, the beam shaping is completed.

[0010] Optionally, the beam quality factor M of the Gaussian beam 2 <1.4.

[0011] Optionally, the step of targeting the pre-alignment mark on the beam shaper and perpendicularly directing the expanded and collimated Gaussian beam into the beam shaper specifically includes:

[0012] The pre-alignment mark is set on the incident end of the beam shaper. The beam shaper is adjusted so that the center of the Gaussian beam enters the center of the pre-alignment mark.

[0013] Optionally, the pre-alignment mark is square or circular, and the marking range of the pre-alignment mark is larger than the passing range of the incident beam of the beam shaper.

[0014] Optionally, the variable magnification beam expander performs beam expansion and collimation on the Gaussian beam, specifically including:

[0015] The energy center coordinates of the light spot are obtained by the light spot analyzer, and the energy center coordinates are used as the first coordinates.

[0016] Adjust the magnification of the variable magnification beam expander to obtain the second coordinate value;

[0017] When the distance between the first coordinate value and the second coordinate value is within a preset range, the expansion and collimation of the Gaussian beam is completed.

[0018] Optionally, after the beam shaping is completed, the beam shaping method further includes:

[0019] A flat-topped laser spot is created on the test material using a laser.

[0020] The test material is sliced, and the spot depth, the first spot width, and the second spot width at half the spot depth are measured on the test material.

[0021] The ratio of the light spot depth to the width of the first light spot and the ratio of the width of the second light spot to the width of the first light spot are calculated respectively to detect the flat top effect.

[0022] Optionally, the ratio of the light spot depth to the first light spot width is 0.5 to 1, and the ratio of the second light spot width to the first light spot width is 0.8 to 1.

[0023] Optionally, the diameter of the beam incident into the beam shaper is 5 to 10 mm, and the roundness is greater than or equal to 90%.

[0024] Optionally, the effective aperture of the variable magnification beam expander is greater than or equal to 2.2 times the beam diameter, and the effective aperture of the beam shaper is greater than or equal to 2.2 times the beam diameter.

[0025] Optionally, the magnification of the variable magnification beam expander is 1.0 to 2.0 times.

[0026] On the other hand, embodiments of the present invention provide a beam shaping device based on the beam shaping method described above. The beam shaping device includes a first adjustment frame for adjusting the magnification of the variable magnification beam expander and a second adjustment frame for adjusting the position of the beam shaper in the X-axis and Y-axis directions. The variable magnification beam expander is mounted on the first adjustment frame, and the beam shaper is mounted on the second adjustment frame.

[0027] In this application, a Gaussian beam is directed towards a pre-alignment mark and then into a beam shaper to achieve coarse alignment between the center of the Gaussian beam and the pre-alignment mark. After the beam enters a spot analyzer, the spot analyzer can acquire the spot image, X-axis energy curve, and Y-axis energy curve. Based on the spot image and the data acquired by the spot analyzer, the magnification of the variable magnification beam expander is adjusted to achieve the incident spot size required by the beam shaper. After adjusting the variable magnification beam expander, the position of the beam shaper in the X-axis and Y-axis directions is adjusted according to the X-axis and Y-axis energy curves. This ensures that the flat-top spot after beam shaping will not exhibit energy tilt in the X and Y directions, resulting in a flat-top spot with uniform energy distribution. This method of shaping the Gaussian beam results in a uniform distribution of the processing beam on the surface of the processed material, uniform heating, and thus improved processing efficiency and effect. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart of a beam shaping method provided in an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the beam spot of the beam shaper provided in an embodiment of the present invention when the incident beam deviates from the pre-alignment mark;

[0031] Figure 3 This is a schematic diagram of a light spot with an excessively large incident light spot diameter provided in an embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of a light spot with an incident light spot diameter that is too small, provided in an embodiment of the present invention;

[0033] Figure 5 This is a schematic diagram of a light spot when the roundness of the light beam is deviated in an embodiment of the present invention;

[0034] Figure 6This is a schematic diagram of the light spot when it deviates from the flat top position according to an embodiment of the present invention;

[0035] Figure 7 This is a schematic diagram of the spot of a Gaussian beam provided in an embodiment of the present invention;

[0036] Figure 8 This is a schematic diagram of the light spot of a flat-top light provided in an embodiment of the present invention. Detailed Implementation

[0037] To make the technical problems solved, the technical solutions, and the beneficial effects 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 of the invention and are not intended to limit the invention.

[0038] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0040] In one embodiment, such as Figure 1 As shown, the present invention provides a beam shaping method, comprising:

[0041] S10: Expand and collimate the Gaussian beam emitted by the laser using a variable magnification beam expander to obtain a beam expanded and collimated Gaussian beam.

[0042] S20: Using the pre-alignment mark on the beam shaper as the target, the expanded and collimated Gaussian beam is vertically injected into the beam shaper. The beam shaper can shape the Gaussian beam to obtain a flat-top beam, so as to obtain the Gaussian beam after the beam shaper.

[0043] S30: A beam analyzer set according to the transmission direction of the optical path projects the Gaussian beam after passing through the beam shaper onto the beam analyzer, and obtains the image of the beam spot, the X-axis energy curve and the Y-axis energy curve through the beam analyzer.

[0044] S40: Adjust the magnification of the variable magnification beam expander and / or the position of the beam shaper in the X and Y axis directions.

[0045] S50: Taking the normal from the center of the light spot to the corresponding axis as the axis of symmetry, when the difference between any two symmetrical points on the X-axis energy curve and the Y-axis energy curve is less than a first preset value, and the distance between the highest point energy value and the lowest point energy value is less than a second preset value, the beam shaping is completed.

[0046] In this application, a pre-alignment mark is set on the beam shaper. The Gaussian beam is directed towards the pre-alignment mark to achieve coarse alignment between the center of the Gaussian beam and the pre-alignment mark. After passing through the beam shaper, the beam enters the spot analyzer. The spot analyzer can collect the spot to obtain the spot image, X-axis energy curve, and Y-axis energy curve. Based on the spot image and the data collected by the spot analyzer, the magnification of the variable magnification beam expander is adjusted to achieve the incident spot size required by the beam shaper. After adjusting the variable magnification beam expander, the position of the beam shaper in the X-axis and Y-axis directions is adjusted according to the X-axis and Y-axis energy curves. This ensures that the flat-top spot after beam shaping will not have energy tilt in the X and Y directions, thus obtaining a flat-top spot with uniform energy distribution. This method of shaping the Gaussian beam can make the processing beam distribution and heating on the surface of the processed material uniform, thereby improving the processing efficiency of the processed material.

[0047] In one embodiment, in step S10, the laser emits a Gaussian beam, such as... Figure 7 The diagram shows a Gaussian beam spot. The variable magnification beam expander can collimate and adjust the directionality of the beam, making the energy distribution of the adjusted beam concentrated and improving the adjustment accuracy of the variable magnification beam expander.

[0048] In one embodiment, the beam quality factor M of the Gaussian beam 2 <1.4. Beam quality is an important parameter of lasers, M 2 The beam quality factor can reflect the essence of beam quality well. In practical applications, beam quality factors within the above range, after being shaped by a beam shaper, result in a flat-top beam with a good flat-top effect.

[0049] In one embodiment, the Gaussian beam is expanded and collimated using a variable magnification beam expander, specifically including the following operations:

[0050] The energy center coordinates of the light spot are obtained by a light spot analyzer, and the energy center coordinates are used as the first coordinates.

[0051] Adjust the magnification of the variable magnification beam expander to obtain the second coordinate value;

[0052] When the distance between the first coordinate value and the second coordinate value is within a preset range, the expansion and collimation of the Gaussian beam is completed.

[0053] The variable magnification beam expander has a conventional structure. The beam analyzer can collect the coordinates of the energy center of the beam spot, recording the initial value as the first coordinate value. By changing the magnification of the variable magnification beam expander, the second coordinate value of the energy center of the beam spot is obtained. The distance between the first and second coordinate values ​​is the deviation value, which represents the pointing deviation of the variable magnification beam expander. The smaller the distance value, the smaller the pointing deviation of the variable magnification beam expander. When the distance value is within the preset range of the deviation value, collimation and pointing adjustment are completed. When the distance value is outside the preset range of the deviation value, the position of the output mirror of the variable magnification beam expander is adjusted to obtain the third coordinate value. When the distance between the third coordinate value and the first coordinate value is within the preset range, the adjustment is complete, and the coaxiality and energy distribution of the beam have been adjusted.

[0054] During collimation adjustment, it is necessary to ensure that the optical axis of the zoom beam expander is in good condition to avoid an increase in aberrations, which would lead to a deterioration in the quality of the flat-top light after collimation.

[0055] Preferably, the variable magnification beam expander is mounted on a four-dimensional adjustment frame, and the position of the output mirror of the variable magnification beam expander is adjusted by the four-dimensional adjustment frame to change the magnification of the variable magnification beam expander.

[0056] In one embodiment, the preset range of the deviation value is 0 to 100 μm. Of course, the preset range here is a preferred range, but it is not limited to this range. The preset range of the deviation value can be determined according to the magnification of the variable magnification beam expander.

[0057] In one embodiment, in step S20, a pre-alignment mark is set on the incident end of the beam shaper. After the collimation and directivity adjustment of the zoom beam expander are completed, it remains stationary, and the position of the beam shaper is adjusted so that the center of the Gaussian beam passing through the zoom beam expander is perpendicularly incident on the center of the pre-alignment mark, thereby achieving coarse alignment adjustment between the Gaussian beam and the beam shaper. Preferably, the beam shaper is mounted on another four-dimensional adjustment frame. Adjusting the position of the beam shaper in the X direction using the X-direction nut on the four-dimensional adjustment frame can change the energy distribution of the light spot in the X direction. Adjusting the position of the beam shaper in the Y direction using the Y-direction nut can change the energy distribution of the light spot in the Y direction.

[0058] In one embodiment, the pre-alignment mark is square or circular, and the marking range of the pre-alignment mark is larger than the passing range of the incident beam of the beam shaper. The beam center of the incident beam should be adjusted to the center of the square or circle.

[0059] In one embodiment, the diameter of the beam incident on the beam shaper is 5–10 mm, the tolerance of the beam diameter is -10% to 10%, the diameter of the incident spot collected by the beam shaper is 5–10 mm, and the roundness of the beam is greater than or equal to 90%. The roundness of the beam is determined by the laser. If the roundness is too small, it will cause uneven energy distribution in the X and Y directions of the flat-top beam, resulting in a poor shaping effect. The roundness can be achieved by adjusting the emission spot inside the laser.

[0060] In one embodiment, in step S30, the spot analyzer is positioned behind the beam shaper in the optical path. That is, the beam emitted by the laser passes through the zoom beam expander and the beam shaper in sequence and then enters the spot analyzer, where a spot image, an X-axis energy curve, and a Y-axis energy curve are displayed.

[0061] The X-axis energy curve shows the energy distribution of the light spot in the X direction. When there is a deviation in energy in the X direction, the X-axis energy curve will show a prominent peak. Taking the line from the center of the light spot to the normal of the X-axis as the axis of symmetry, if the energy of the light spot in the X-axis direction is concentrated at the center of the light spot, the peak will appear closer to the axis of symmetry. If the energy of the light spot in the X-axis direction is concentrated at the outer edge of the light spot, the peak will appear farther from the axis of symmetry.

[0062] Similarly, the energy distribution of the light spot in the Y direction can be seen through the Y-axis energy curve. When there is a deviation in energy in the Y direction, the specific manifestation on the Y-axis energy curve is the appearance of a prominent peak. Taking the line from the center of the light spot to the normal of the Y-axis as the axis of symmetry, if the energy of the light spot in the Y-axis direction is concentrated in the center of the light spot, the peak appears in a position closer to the axis of symmetry. If the energy of the light spot in the Y-axis direction is concentrated in the outer ring of the light spot, the peak appears in a position farther from the axis of symmetry.

[0063] In one embodiment, a position 400 μm away from the axis of symmetry can be used as a boundary. In the X-axis or Y-axis direction, when the peak appears within 400 μm of the axis of symmetry, it indicates that the energy is concentrated in the center of the light spot. When the peak is not within 400 μm of the axis of symmetry, it indicates that the energy is concentrated in the outer ring of the light spot.

[0064] In one embodiment, in step S40, factors affecting the quality of the flat-top light include: the incident beam of the beam shaper deviating from the pre-alignment mark, the incident spot diameter being too large or too small, and the effective aperture of the optical devices in the beam path. When these situations occur, it is necessary to adjust the magnification of the variable magnification beam expander and / or adjust the position of the beam shaper in the X and Y axis directions to adjust the energy distribution of the spot and obtain a flat-top light with uniform energy distribution. Figure 8 The image shown is a schematic diagram of the light spot of a flat-top light source.

[0065] Specifically, such as Figure 2As shown, when the incident beam of the beam shaper deviates from the pre-alignment mark, the incident beam will deviate in two directions (X and Y directions) from the center of the beam shaper, causing the energy of the flat-top beam spot to tilt in both directions. At this time, it is necessary to adjust the position of the beam shaper in the X and Y directions using a four-dimensional adjustment frame to eliminate the positional influence of the X and Y directions and make the energy distribution uniform.

[0066] The diameter of the incident light spot collected by the beam shaper is 5–10 mm, such as Figure 3 As shown, when the incident light spot diameter is too large, the energy in the outer ring of the flat-top light spot becomes too high. In this case, it is necessary to increase the magnification of the zoom beam expander to enlarge the incident light spot and make the energy distribution in the inner and outer rings of the shaped light spot more uniform. Figure 4 As shown, if the incident beam is too small, the energy will be concentrated in the middle of the beam spot, resulting in a poor flat-top effect after reshaping. Therefore, the magnification of the variable magnification beam expander needs to be reduced.

[0067] In one embodiment, the magnification of the variable magnification beam expander is 1.0 to 2.0 times. The incident spot size of the beam shaper is the product of the incident spot size of the variable magnification beam expander and the beam expansion magnification. The diameter of the incident spot of the beam shaper needs to be determined according to the actual processing requirements, and the magnification of the variable magnification beam expander is adjusted according to the required incident spot size of the beam shaper to achieve the required spot size of the beam shaper.

[0068] In one embodiment, the effective aperture of the optics along the beam path affects the flat-top effect. The minimum effective aperture of all optical sections along the beam path is 2.2 times the beam diameter; that is, the effective aperture of the zoom beam expander is greater than or equal to 2.2 times the beam diameter, and the effective aperture of the beam shaper is greater than or equal to 2.2 times the beam diameter. As the beam diameter increases, the effective apertures of the zoom beam expander and the beam shaper should also increase proportionally.

[0069] In one embodiment, such as Figure 5 As shown, the roundness (ellipticity) of the beam can also cause uneven energy distribution in the X and Y directions, affecting the flat-top effect. The greater the roundness deviation, the greater the difference in energy distribution of the beam. However, the roundness of the beam is determined by the laser, and the required roundness can be achieved by adjusting the emitted beam spot inside the laser. It cannot be achieved by adjusting the beam shaper and the variable magnification beam expander.

[0070] In one embodiment, such as Figure 6 As shown, the working distance also affects the flat-top effect. After beam shaping, the beam is focused by a focusing lens. The focused beam spot will only have a flat-top effect at a specific position. When it deviates from the flat-top position, different degrees of diffraction will occur.

[0071] The effective distance of the flat-top position is within ±2mm of the focal length. By fine-tuning the working distance, the shape of the light spot will gradually rise to form a cone shape, and then be further adjusted to make the top of the cone gradually smooth, finally obtaining the flat-top light profile.

[0072] In one embodiment, in step S50, when determining whether the debugging is complete, the determination is made based on whether the difference between any two symmetrical points on the X-axis energy curve and the Y-axis energy curve is less than a first preset value, and whether the distance between the highest point energy value and the lowest point energy value is less than a second preset value. The first preset value is 200 μm, and the second preset value is 100 μm.

[0073] Specifically, take any two symmetrical points on the X-axis energy curve. The difference between the corresponding values ​​of the two points on the Y-axis should be less than a first preset value. There are climbing regions at both ends of the X-axis energy curve. When determining the energy values ​​of the highest and lowest points, the climbing regions are excluded from the calculation range. Find the highest and lowest points on the X-axis energy curve, obtain the corresponding values ​​of the highest and lowest points on the Y-axis, and calculate the difference. This difference should be less than a second preset value.

[0074] Take any two symmetrical points on the Y-axis energy curve. The difference between the corresponding values ​​of the two points on the X-axis is less than a first preset value. There are climbing regions at both ends of the Y-axis energy curve. When determining the energy values ​​of the highest and lowest points on the Y-axis energy curve, exclude the climbing regions from the calculation range, find the highest and lowest points on the Y-axis energy curve, obtain the corresponding values ​​of the highest and lowest points on the X-axis, and calculate the difference. This difference must be less than a second preset value.

[0075] When the difference between any two symmetrical points is less than 200μm, and the distance between the highest and lowest energy values ​​is less than 100μm, the energy curve will show no prominent peaks, indicating that the energy distribution of the light spot is uniform and without shift, forming a flat-top light, thus completing the debugging.

[0076] In one embodiment, after beam shaping is completed, the shaping effect can be verified by focusing the beam to produce a flat-topped beam spot on the test material. The beam shaping method further includes:

[0077] After debugging, a flat-topped light spot is projected onto the test material using a laser;

[0078] The test material is sliced, and the spot depth, the first spot width, and the second spot width at half the spot depth are measured on the test material.

[0079] The ratio of the light spot depth to the width of the first light spot and the ratio of the width of the second light spot to the width of the first light spot are calculated respectively to detect the flat top effect.

[0080] When creating a flat-top light spot, multiple light spots are projected onto the test material in rows or columns. Afterward, the test material is sliced ​​to observe the shape of the light spots and measure the spot depth, the width of the first light spot, and the width of the second light spot at half the depth. The width of the first light spot is actually the aperture of the flat-top light spot on the test material. The ratio of the spot depth to the width of the first light spot is calculated, as is the ratio of the width of the second light spot to the width of the first light spot. When both ratios are within the set range, it indicates that the flat-top effect is good.

[0081] In one embodiment, the ratio of the beam depth to the width of the first beam is 0.5 to 1, and the ratio of the width of the second beam to the width of the first beam is 0.8 to 1. When the beam is within the above range, it indicates that the flat-top effect is good. When it is outside the above range, it indicates that the flat-top effect is poor and further adjustments are needed. Generally, after the position of the beam shaper and the magnification of the variable magnification beam expander are properly adjusted, a good flat-top beam effect can be obtained.

[0082] In the above embodiments, when inspecting the flat-top effect, lines can be made on the test material using a laser. After slicing, the depth of the lines, the width of the lines on the surface of the test material, and the line width at half the hole depth need to be measured, and the ratios calculated.

[0083] On the other hand, the present invention provides a beam shaping device based on the beam shaping method described above, including a first adjustment frame for adjusting the magnification of a variable magnification beam expander and a second adjustment frame for adjusting the position of a beam shaper in the X-axis and Y-axis directions, wherein the variable magnification beam expander is mounted on the first adjustment frame and the beam shaper is mounted on the second adjustment frame.

[0084] The first and second adjustment frames are four-dimensional adjustment frames, and they differ from each other. The structure of the four-dimensional adjustment frame is conventional and will not be described in detail. The magnification of the variable magnification beam expander can be changed by altering the position of its output mirror using the first adjustment frame. The position of the beam shaper in the X and Y axes can be adjusted using the nuts in the X and Y directions on the second adjustment frame.

[0085] The above description is only 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 protection scope of the present invention.

Claims

1. A method of beam shaping, characterized by, The method comprises the following steps: a variable expansion collimator is used to expand and collimate a Gaussian beam emitted by a laser; a pre-alignment mark on a beam shaper is used as a target, and the expanded and collimated Gaussian beam is vertically injected into the beam shaper; a spot analyzer arranged in a light path transmission direction is used to project the Gaussian beam after the beam shaper on the spot analyzer to obtain a flat-top spot, and an image, an X-axis energy curve and a Y-axis energy curve of the flat-top spot are obtained through the spot analyzer; a magnification of the variable expansion collimator and / or positions of the beam shaper in X-axis and Y-axis directions are adjusted; a normal line from a center of the flat-top spot to a corresponding axis is used as a symmetry axis, and when a difference between any two symmetrical points on the X-axis energy curve and the Y-axis energy curve is less than a first preset value, and a distance between a highest point energy value and a lowest point energy value is less than a second preset value, the beam shaping is completed.

2. The method of claim 1, wherein, the beam quality factor M of the Gaussian beam 2 <1.

4.

3. The method of claim 1, wherein the beam shaping element is a lens. The pre-alignment mark is arranged on an incident end of the beam shaper, and the beam shaper is adjusted so that a beam center of the Gaussian beam is injected into a center of the pre-alignment mark. The pre-alignment mark is a square or a circle, and a mark range of the pre-alignment mark is greater than a passing range of an incident beam of the beam shaper.

4. The method of claim 3, wherein the beam shaping element is a lens. The variable expansion collimator expands and collimates the Gaussian beam, and the method comprises the following steps:

5. The method of claim 1, wherein, the energy center coordinate value of the flat-top spot is obtained through the spot analyzer, and the energy center coordinate value is used as a first coordinate value; a magnification of the variable expansion collimator is adjusted to obtain a second coordinate value; when a distance value between the first coordinate value and the second coordinate value is within a preset range, the expansion and collimation of the Gaussian beam is completed. After the beam shaping is completed, the method further comprises the following steps:

6. The method of claim 1, wherein, a laser is used to mark the flat-top spot on a test material; the test material is sliced, and a spot depth, a first spot width and a second spot width at a half spot depth of the flat-top spot on the test material are measured; ratios of the spot depth to the first spot width and the second spot width to the first spot width are calculated respectively to detect a flat-top effect. The ratio of the spot depth to the first spot width is 0.5-1, and the ratio of the second spot width to the first spot width is 0.8-1.

7. The method of claim 6, wherein the beam shaping element is a lens. A beam diameter of the beam injected into the beam shaper is 5-10 mm, and a true circularity is greater than or equal to 90%.

8. The method of claim 1, wherein, An effective aperture of the variable expansion collimator is greater than or equal to 2.2 times of the beam diameter, and an effective aperture of the beam shaper is greater than or equal to 2.2 times of the beam diameter.

9. The method of claim 8, wherein the beam shaping element is a lens. The magnification of the variable expansion collimator is 1.0-2.0 times.

10. The method of claim 1, wherein, ​ 11. An optical beam shaping device, characterized by Based on the light beam shaping method as claimed in any one of claims 1-10, the light beam shaping device comprises a first adjusting frame for adjusting the magnification of the variable magnification beam expander and a second adjusting frame for adjusting the position of the light beam shaper in the X-axis and Y-axis directions, the variable magnification beam expander is mounted on the first adjusting frame, and the light beam shaper is mounted on the second adjusting frame.

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