A method and system for compensating laser beam spot rotation in laser processing

Abstract

The present invention discloses a method for compensating laser beam rotation in laser processing, comprising the following steps: S1: Complete the debugging of the light spot and adjust the shaping device to the standard position; S2: Select several characteristic positions within the entire processing area, and use a laser to process several light spots on the calibration object at the characteristic positions, and measure the corresponding laser beam rotation amounts of each light spot; S3: According to the laser beam rotation amounts corresponding to the light spots at each characteristic position, fit the relationship between the compensation angle of the shaping device and the processing position coordinates of the entire processing area; S4: Control the shaping device to rotate to compensate for the laser beam rotation amount and perform laser processing. The present invention also discloses a corresponding processing system. The present invention adopts a real-time compensation method, and compensates for the angular rotation of the light spot by rotating the shaping device, solving the problem of poor processing accuracy caused by the deformation and rotation of the light spot at the edge of the processing area in the laser scanning processing of large-size square light spots, and improving the processing quality and processing accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser processing applications, and particularly relates to a method and system for laser processing with spot rotation compensation. Background Art

[0002] In the field of laser processing, a method of using a galvanometer in cooperation with a field lens is usually adopted for processing. For fields with special requirements, a non-circular spot needs to be used for processing. In the processing using a non-circular spot, when the processing accuracy requirement is not high, the distortion of the spot caused by the galvanometer-field lens system under large-field incidence, such as spot deformation, rotational distortion, etc., on the processing effect can be ignored.

[0003] However, with the extensive and in-depth development of laser processing technology, higher requirements have been put forward for the accuracy, quality, and efficiency of laser processing in various industries, especially in the laser processing technology of solar cells. This requires: on the one hand, increasing the spot size, and on the other hand, ensuring the processing accuracy and efficiency at the same time.

[0004] In the application scenario of processing with a non-circular spot, taking a square spot as an example, the laser emitted by the laser usually obtains a square spot through a shaper, and then is scanned by a scanning system composed of a field lens and a galvanometer and focused by the field lens system to complete the processing. Due to the distortion of the scanning system of the galvanometer and the field lens under large-angle processing, the spot at the corresponding position (the edge of the processing field) will generate rotational deformation. Through theoretical simulation and calculation, it is known that the farther the field of view is from the center, the more obvious the deformation and distortion of the spot are. As Figure 1 shown, when performing line processing, after these rotating spots are connected into a line, the edge of the line appears serrated, and the linear dimension of the serrations is proportional to the size of the spot, seriously affecting the processing quality and making it difficult to meet the high-precision and high-quality laser processing requirements.

[0005] Therefore, it is very necessary to propose a laser processing method applicable to non-circular spots. Summary of the Invention

[0006] In view of one or more of the above defects or improvement requirements of the prior art, the present invention provides a method and system for laser processing with spot rotation compensation. By adopting a real-time compensation method, the angular rotation of the spot is compensated by rotating the shaping device, and the problem of poor processing accuracy caused by the deformation and rotation of the spot at the edge of the processing field in the scanning processing of a large-size square laser spot is solved.

[0007] To achieve the above object, according to one aspect of the present invention, a method for laser processing with spot rotation compensation is provided, including the following steps:

[0008] S1: Complete spot debugging and adjust the shaping device to the standard position;

[0009] S2: Select several characteristic positions within the entire processing width. At the characteristic positions, use a laser to process several light spots on the calibration object, and measure the spot rotation amount corresponding to each light spot.

[0010] S3: According to the spot rotation amounts corresponding to the light spots at each characteristic position, fit the relationship between the compensation angle of the shaping device and the processing position coordinates of the entire processing width.

[0011] S4: According to the relationship between the compensation angle of the shaping device and the processing position coordinates of the entire processing width, control the shaping device to rotate to compensate for the spot rotation amount and perform laser processing.

[0012] As a further improvement of the present invention, the light spot is a non-circular light spot, and its shape is square, rectangular, elliptical or linear.

[0013] As a further improvement of the present invention, in step S1, adjusting the shaping device to the standard position includes: initially adjusting the angle of the shaping device so that the light spot at the center of the processing width has no rotation.

[0014] As a further improvement of the present invention, in step S2, divide each side length of the entire processing width into m - 1 equal parts, where m ≥ 3, select m * m symmetric characteristic positions, and the coordinates of each characteristic position are (x i , y j );

[0015] Taking the straight line formed by the light spots when the shaping device has no rotation as the line processing direction reference line, measure the rotation angle θ(x i , y j ) between the spot rotation direction reference line and the line processing direction reference line at each characteristic position, where i = 1, 2, 3....m, j = 1, 2, 3....m.

[0016] As a further improvement of the present invention, take the straight line formed by the lowest or highest points of the light spots as the line processing direction reference line; or, take the standard straight line formed by the centers of the light spots as the line processing direction reference line;

[0017] For a square light spot or a rectangular light spot, take the bottom side length or the top side length direction of the light spot as the rotation direction reference line; for an elliptical light spot or a linear light spot, take the direction of the vertex connection as the rotation direction reference line.

[0018] As a further improvement of the present invention, the spot rotation amount is positive when the line processing direction reference line turns to the rotation direction reference line, and the compensation angle corresponding to the shaping device is -θ(x i , y j );

[0019] Alternatively, when the rotation from the reference line of the wire processing direction to the reference line of the rotation direction is negative, the compensation angle corresponding to the shaping device is +θ(x i ,y j ).

[0020] As a further improvement of the present invention, the fitting method is as follows: for any position (x m , y n ) within the processing area, according to its distances from the four closest feature positions and weights, calculate the spot rotation amount as shown in Equation (1):

[0021]

[0022] where θ i，j , θ i+1j , θ i，j+1 , θ i+1，j+1 are the spot rotation amounts of the four feature positions x m , y n ) closest to the position (x i , x j , x i+1 , x j , x i , x j+1 , x i+1 , x j+1 respectively, and a, b, c, d are the perpendicular distances from the position (x m , y n ) to the pairwise connecting lines of the four feature positions, and L is the distance between the pairwise connecting lines of adjacent feature positions.

[0023] As a further improvement of the present invention, the fitting method is as follows: based on the measured spot rotation amounts corresponding to each feature position, establish the relationship between the spot rotation amount and the feature position across the entire processing area, and through this relationship between the spot rotation amount and the feature position, fit to obtain the relationship between the spot rotation amount and the position at any position across the entire processing area as shown in Equation (2):

[0024]

[0025] Substitute a1, b1, c1, d1 and the feature position coordinates (x i , y i ) into the calculation one by one until the numerical values of the spot rotation amounts of all feature positions calculated are equal to the measured numerical values or reach the set error, thereby determining the coefficients a1, b1, c1, d1;

[0026] For non-feature position spots, substitute a1, b1, c1, d1 and their position coordinates into Equation (2) to obtain the corresponding spot rotation amount.

[0027] As a further improvement of the present invention, the shaping device is fixed on the spectacle frame, and at the same time, the spectacle frame is fixed on the rotary motor. Under the action of the rotary motor, the shaping device rotates along the direction perpendicular to its incident and outgoing light directions; the compensation angle of the shaping device is adjusted by rotating the shaping device by -θ(x i , y j ) or +θ(x i , y j ) angles in the direction perpendicular to the laser incident direction.

[0028] As a further improvement of the present invention, a hollow rotary platform is provided on the hollow rotary motor, and the spectacle frame is matched with the hollow rotary platform.

[0029] According to another aspect of the present invention, a spot rotation compensation laser processing system is provided, which is applied to the spot rotation compensation laser processing method described above, and includes a laser, a shaper assembly, a galvanometer scanner, and a field lens arranged in sequence along the optical path, and further includes a controller; wherein,

[0030] The shaper assembly includes a shaping device, which is fixed on the spectacle frame, and at the same time, the spectacle frame is fixed on the hollow rotary motor. Under the rotation action of the hollow rotary motor, the shaping device rotates along the direction perpendicular to its incident and outgoing light directions;

[0031] The controller is electrically connected to the hollow rotary motor and the galvanometer scanner, so as to control the galvanometer scanner to perform processing according to the set speed and path, and at the same time control the hollow rotary motor to rotate by a corresponding rotation amount at a specific processing position for angle compensation.

[0032] As a further improvement of the present invention, a hollow rotary platform is provided on the hollow rotary motor, and the spectacle frame is matched with the hollow rotary platform.

[0033] As a further improvement of the present invention, a beam expander corresponding to the laser is further included, and a reflector is further provided on the optical path between the beam expander and the shaper assembly.

[0034] Generally speaking, compared with the prior art by the above technical solutions conceived by the present invention, the following beneficial effects are obtained:

[0035] (1) In the spot rotation compensation laser processing method of the present invention, by controlling the dynamic rotation of the shaping device during the processing, corresponding angle compensation is performed on the spots at different positions on the processing surface, and non-rotational deformation of the full-surface spots can be achieved. The present invention adopts a real-time compensation method to compensate the angular rotation of the spot by rotating the shaping device, solves the problem of poor processing accuracy caused by the deformation and rotation of the spots at the edge of the processing surface in the laser large-size square spot scanning processing, and improves the processing quality and processing accuracy.

[0036] (2) The spot rotation compensation laser processing system of the present invention only needs to set a rotating component corresponding to the shaping device on the basis of the existing laser processing system, without replacing each component in the laser processing system, which is convenient for processing, and improves the processing efficiency while ensuring the laser processing quality. Description of the Drawings

[0037] Figure 1 Schematic diagram of a serrated laser processing line in the prior art;

[0038] Figure 2 Schematic diagram of a square spot at the characteristic position of the processing width in the embodiment of the present invention;

[0039] Figure 3 Schematic diagram of the rotation angle of the spot in the embodiment of the present invention;

[0040] Figure 4 Schematic diagram of the position of the light spot of a fitting method provided in the embodiment of the present invention;

[0041] Figure 5 Angle compensation table for the entire processing width in the embodiment of the present invention;

[0042] Figure 6 Line diagram composed of square spots after rotation compensation processing in the embodiment of the present invention;

[0043] Figure 7 Schematic diagram of the overall structure of the spot rotation compensation laser processing system in the embodiment of the present invention;

[0044] Figure 8 Schematic diagram of the structure of the shaper assembly involved in the spot rotation compensation laser processing system in the embodiment of the present invention;

[0045] Figure 9 Schematic diagram of the control principle involved in the spot rotation compensation laser processing system in the embodiment of the present invention.

[0046] In all the drawings, the same reference numerals represent the same technical features, specifically: 1 - laser, 2 - shaper assembly, 3 - galvanometer scanner, 4 - field lens, 5 - beam expander, 6 - reflector, 7 - controller; 21 - shaping device, 22 - lens holder, 23 - hollow rotary motor. Detailed Embodiments

[0047] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present 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 only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0048] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention.

[0049] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0050] In the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] In the present invention, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature may be that the first feature is directly above or obliquely above the second feature, or simply indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "under" the second feature may be that the first feature is directly below or obliquely below the second feature, or simply indicates that the first feature has a lower horizontal height than the second feature.

[0052] An embodiment of the present invention provides a method for compensating laser processing for spot rotation, which is applicable to the field of non-circular spot laser processing, especially applicable to the processing of large-size non-circular spots (such as square spots, rectangular spots, elliptical spots, linear spots, etc.). The method includes the following steps:

[0053] (1) Complete spot debugging and adjust the shaping device to the standard position;

[0054] Specifically, by adjusting the basic optical path such as the beam expander, shaping device, etc., the spot to be processed is obtained, and by initially adjusting the angle of the shaping device, the spot at the center of the processing area has no rotation. Taking a square spot as an example, the square spot to be processed is debugged, and the square spot at the center of the processing area has no rotation.

[0055] Preferably, in this step, the galvanometer accuracy is also corrected, which can be achieved by conventional grid correction and will not be elaborated here. By correcting the galvanometer accuracy, the galvanometer can accurately move to the processing position coordinates, so as to ensure that during subsequent laser processing, the position coordinates correspond to the rotation angle of the shaping device.

[0056] (2) Measure the spot rotation amount at the characteristic positions;

[0057] Select several characteristic positions within the entire processing area, where the coordinates of each characteristic position are (x i , y j ). At the characteristic positions, use a laser to process several light spots on the calibration object, and measure the rotation angle θ(x i , y j ) corresponding to the light spots at this position.

[0058] Specifically, as a non-limiting implementation method, as Figure 2 and Figure 3 shown, divide each side length of the entire processing area into (m - 1) equal parts (where m ≥ 3), select m * m (symmetric with respect to the xy coordinate axes) characteristic positions, and the coordinates of each characteristic position are (x i , y j ), where i = 1, 2, 3... m, j = 1, 2, 3... m; use a laser to process light spots at these characteristic positions on the calibration object, and use the standard straight line formed by the light spots when the shaping device is not rotated as the line processing direction reference line, and measure the spot rotation angle θ(x i , y j ) between the spot rotation direction reference line and the line processing direction reference line at each characteristic position, where i = 1, 2, 3... m, j = 1, 2, 3... m.

[0059] Preferably, the reference line of the wire machining direction is the standard straight line formed by connecting the lowest or highest points of the light spots, which is easier to capture and measure. Of course, the standard straight line formed by connecting the centers of the light spots can also be used as the reference line of the wire machining direction.

[0060] Preferably, for square or rectangular light spots, etc., the reference line of the rotation direction can be the bottom side length or the top side length direction of the light spot, which is easier to capture and measure. For elliptical light spots, etc., the direction of connecting the vertices is selected as the reference line of the rotation direction.

[0061] Optionally, taking the rotation from the reference line of the wire machining direction to the reference line of the rotation direction as positive (+θ), or taking the rotation from the reference line of the wire machining direction to the reference line of the rotation direction as negative (-θ), the rotation angle of each feature position is determined. In the present invention Figure 3 In a preferred embodiment of the present invention, the rotation from the reference line of the wire machining direction to the reference line of the rotation direction is positive.

[0062] During specific operation, the calibration object after laser machining can be visually inspected to measure the rotation angle θ(x i , y j ) between the reference line of the rotation direction of the light spot and the reference line of the wire machining direction at each feature position. The rotation angle θ(x i , y j ) of the light spot and the straight line can be detected visually by using the existing technology, which will not be elaborated here.

[0063] It should be noted that the entire machining area can be the maximum machining area of the galvanometer field lens. According to the method of this step, the light spot rotation amount at the feature positions of the entire machining area of the galvanometer field lens can be obtained. Of course, the maximum machining area of the galvanometer field lens is usually larger than or slightly larger than the area of the object to be machined or the pattern to be machined. The entire machining area of this step can also be the size of the object to be machined or the size of the pattern to be machined on the object to be machined. According to the method of this step, the light spot rotation amount at the feature positions within the size of the object to be machined or the size of the pattern to be machined can be obtained. Therefore, how to specifically determine the machining area can be selected by those skilled in the art according to the machining needs.

[0064] As a preferred implementation manner, when each side length of the entire machining area is equally divided into (m - 1) parts, it can be equally divided according to the planned laser machining pattern, where m is the number of lines of the pattern to be machined. This setting method is more in line with the actual machining, saving time and having a good fitting effect.

[0065] And it can be understood that the method of equally dividing each side length of the entire machining area into (m - 1) parts preferably obtains more uniform or symmetric feature positions within the entire machining area, but this application is not limited thereto, and non-uniform division can also be performed according to needs.

[0066] (3) According to the spot rotation amount at each feature position, the relationship between the compensation angle of the shaping device and the processing position coordinates of the entire processing area is obtained by fitting.

[0067] Specifically, when the spot rotation amount is positive from the reference line of the line processing direction to the reference line of the rotation direction, the corresponding compensation angle of the shaping device is -θ(x i , y j ); when the spot rotation amount is negative from the reference line of the line processing direction to the reference line of the rotation direction, the corresponding compensation angle of the shaping device is +θ(x i , y j ). The adjustment of the compensation angle of the shaping device is completed by rotating the shaping device by the corresponding angle in the direction perpendicular to the laser incident direction. This angle is based on the standard position in step (1) and is rotated clockwise or counterclockwise by θ(x i , y j ) angle. For the specific operation of clockwise or counterclockwise, those skilled in the art can determine it according to the actual rotation and deformation direction of the spot at each processing position coordinate.

[0068] For the spots at non-feature positions, the relationship between the compensation angle of the shaping device and the processing position coordinates needs to be determined by fitting. When fitting, in some embodiments, first convert the spot rotation amount at the feature position into the compensation angle of the shaping device, and then fit the compensation angles of the entire processing area to obtain the relationship between the compensation angle of the shaping device and the processing position coordinates of the entire processing area; in other embodiments, first fit the spot rotation amounts of the entire processing area, and then convert them into the compensation angles of the shaping device to obtain the relationship between the compensation angle of the shaping device and the processing position coordinates of the entire processing area.

[0069] Taking the first fitting method as an example, as an optional fitting method, see Figure 4 , where (x m , y n ) is an arbitrary position within the processing area. According to its distances from the four closest feature positions and weights, calculate its spot rotation amount As shown in Equation (1):

[0070]

[0071] Among them, θ i，j , θ i+1j , θ i，j+1 , θ i+1，j+1 are the spot rotation amounts of the unknown position x m , y n from the four feature positions (x i , x j ), (x i+1 , x j), (x i , x j+1 ), (x i+1 , x j+1 ), the spot rotation amounts of (x m , y n ), a, b, c, and d are respectively the perpendicular distances from the unknown position (x

[0072] As another optional fitting method, according to the measured spot rotation amounts θ(x i , y j ) corresponding to each characteristic position (x i , y i ), establish the relationship between the spot rotation amount and the characteristic position on the entire processing surface. As shown in Figure 5 , it is the relationship table of the spot rotation amounts from θ 11 to θ mm and the characteristic position, and through the fitting of the spot rotation amount and the characteristic position, obtain the relationship between the spot rotation amount and the position at any position on the entire processing surface as shown in Equation (2):

[0073]

[0074] Among them, the coefficients a1, b1, c1, and d1 are obtained from the relationship between the spot rotation amount and the characteristic position. For example, through the least squares method, substitute a1, b1, c1, and d1 and the characteristic position coordinates (x i , y i ) one by one for calculation until the calculated values of θ 11 to θ mm are all equal to the measured values (or reach the set error), so as to determine the coefficients a1, b1, c1, and d1.

[0075] For the non-characteristic position spots at any position, substitute a1, b1, c1, d1 and their position coordinates into Equation (2) to obtain the corresponding spot rotation amount.

[0076] (4) According to the processing position coordinates, in accordance with the relationship between the shaping device compensation angle and the processing position coordinates on the entire processing surface described above, control the shaping device to rotate to compensate for the spot rotation angle and perform laser processing;

[0077] Specifically, when the galvanometer processing position is (x i , y j ), control the shaping device to rotate -θ(x i , y j ) or +θ(x i , y j) Compensate the rotation angle of the light spot in real time.

[0078] More specifically, the shaping device can be rotated under the drive of a rotating motor along a direction perpendicular to its light input and output direction. The rotating motor preferably adopts a hollow rotating motor, so as to control the coaxial rotation of the shaping device and the light input and output direction.

[0079] During laser processing, the galvanometer processing scheme (processing path, processing speed) can be preset, and the rotation amount of the aforementioned shaping device can be preset into the rotating motor, so as to perform rotation compensation processing under the corresponding processing path and processing speed. Of course, when higher processing accuracy is required, the processing position coordinates of the light spot can be monitored in real time and sent to the hollow rotating motor for real-time compensation of the rotation angle of the light spot.

[0080] In addition, it should be noted that the present invention only selects limited characteristic position coordinates to measure the rotation angle of its light spot. For the unmeasured area, the corresponding light spot rotation amount is between the two adjacent characteristic positions, approximately linear. The denser the sampling of the characteristic position coordinates, the more linear the fitting relationship tends to be, but the measurement time and difficulty are greater. And the rotation amount and compensation angle of the light spot are related to the optical characteristics of the field lens used, etc. Therefore, in actual application, the number of characteristic positions needs to be selected according to the actual situation and the corresponding fitting relationship needs to be determined.

[0081] The light spot rotation compensation laser processing method of the present invention can achieve the effect of non-rotational deformation of the light spot across the entire processing area by dynamically rotating the shaping device during the processing process to compensate the light spot at different positions on the processing area by corresponding angles, solving the problem of poor processing accuracy caused by the deformation and rotation of the light spot at the edge of the processing area in the laser large-size non-circular light spot scanning processing, and improving the processing quality and processing accuracy.

[0082] Further, referring to Figure 7 , the present invention also provides a light spot rotation compensation laser processing system, which includes a laser 1, a shaping component 2, a galvanometer 3 and a field lens 4 arranged in sequence along the optical path. Among them, the shaping component 2 includes a shaping device 21, which can be rotated under the drive of a rotating motor along a direction perpendicular to its light input and output direction.

[0083] Specifically, as Figure 8 shown, the shaping device 21 is preferably a homogenizing shaping DOE, which is fixed on the mirror frame 22. At the same time, the mirror frame 22 is fixed on the hollow rotating motor 23. The hollow rotating motor 23 is provided with a hollow rotating platform, and the mirror frame 22 matches the hollow rotating platform; the hollow rotating platform is driven by the coaxial rotating hollow rotating motor 23 to rotate, thereby driving the shaping device 21 and the mirror frame 22 to rotate. During laser processing, the rotation angle of the shaping device 21 is adjusted in real time, and finally the rotation angle of the light spot is compensated in real time.

[0084] The laser processing system for spot rotation compensation of the present invention further includes a controller 7, which is electrically connected to the galvanometer 3 and the hollow rotary motor 23.

[0085] As Figure 9 shown, for the laser processing system for spot rotation compensation of the present invention, its control principle and process are as follows: The controller 7 is electrically connected to the hollow rotary motor 23 and the galvanometer 3 respectively, so as to control the galvanometer 3 to perform processing according to the set speed and path, and at the same time control the hollow rotary motor 23 to rotate at a corresponding rotation angle at a specific processing position for angle compensation, so as to control the shaping device to rotate by a corresponding angle at the corresponding processing position, realizing real-time compensation of its rotation angle.

[0086] In addition, the controller 7 is also electrically connected to the laser 1 to control the turning on and off of the laser, so that in laser processing, the light is emitted when the galvanometer moves to the processing position, and the light is turned off at the non-processing position.

[0087] In a preferred embodiment, the laser processing system for spot rotation compensation of the present invention further includes a spot position detection device for detecting the spot position in real time. The controller 7 is electrically connected to the spot position detection device, and can obtain the real-time position of the spot, so as to control the hollow rotary motor 23 to rotate at a corresponding rotation angle at the corresponding real-time processing position for angle compensation.

[0088] In a preferred embodiment, the rotation compensation laser processing system of the present invention further includes a beam expander 5 provided corresponding to the laser 1. Further preferably, a reflector 6 for optimizing the optical path direction is further provided on the optical path between the beam expander 5 and the shaping component 2.

[0089] It should be noted that in the rotation compensation laser processing system of the present invention, the laser 1, the galvanometer 3, the field lens 4, the beam expander 5, the reflector 6, the controller 7, and the shaping device (homogenizing and shaping DOE) all adopt existing technologies. And the connection method of the shaping component in the overall laser processing system does not need to be changed. Only on the basis of the existing laser processing system, a rotating component corresponding to the shaping device is set, and the rotation of the shaping device is realized through the rotating component. Therefore, the laser processing system of the present invention does not need to replace the components in the traditional laser processing system, and improves the processing efficiency while ensuring the laser processing quality.

[0090] To better illustrate the rotation compensation laser processing method and system of the present invention, the following specific embodiments are provided. The following embodiments adopt the laser method and system disclosed in the present invention to perform the de-filming process of solar cells. This process removes the film layer on a specific area of the silicon wafer, and needs to be accurately aligned with the subsequent screen printing process, with extremely high requirements for the spot position accuracy, and no deformation such as spot rotation and distortion is allowed.

[0091] Embodiment 1

[0092] This embodiment takes the cell size of 182mm * 182mm, the number of wire processed is 182, and the interval is 1mm as an example. The beam emitted by the laser is expanded by a beam expander, shaped by a shaping device (homogenizing and shaping DOE), and finally incident on the field lens, being focused on the focal plane to form a large-size square spot.

[0093] Among them, the incident laser wavelength is 532nm, the beam diameter after expanding the laser beam is 7mm, after being focused by the field lens, the focused spot size is 120μm, and the spot overlap rate is 0%.

[0094] The results show that:

[0095] As a control, when the spot rotation compensation laser processing method of the present invention is not used (the shaper does not rotate), the spot generates a rotation of about 3.2° at the edge of the 182mm * 182mm area, and the maximum sawtooth linearity is 6.7μm. It affects the straightness of wire processing, the accuracy of the processed pattern is not good, and it is not conducive to the subsequent etching process.

[0096] After using the spot rotation compensation laser processing method of the present invention, taking the measurement of the spot rotation amount at the characteristic position according to m being 19 (18 equal parts for each side length of the entire processing area) as an example, during laser processing, the rotation of the spot generated at the edge of the 182mm * 182mm area is corrected to less than 0.5°, and the corresponding sawtooth linearity < 2.5μm. The straightness of wire processing is good, which is conducive to the subsequent etching process and has a good processing effect.

[0097] Example 2

[0098] This embodiment takes the cell size of 210mm * 210mm, the number of wire processed is 210, and the interval is 1mm as an example. The beam emitted by the laser is expanded by a beam expander, shaped by a shaping device (homogenizing and shaping DOE), and finally incident on the field lens, being focused on the focal plane to form a large-size square spot.

[0099] Among them, the incident laser wavelength is 532nm, the beam diameter after expanding the laser beam is 7mm, after being focused by the field lens, the focused spot size is 400μm, and the spot overlap rate is 0%.

[0100] The results show that:

[0101] As a control, when the spot rotation compensation processing method of the present invention is not used (the shaping device does not rotate), the spot generates a rotation of about 3.6° at the edge of 210mm * 210mm, and the maximum sawtooth linearity is 25μm. It affects the straightness of wire processing, the accuracy of the pattern is not good, and it is not conducive to the subsequent etching process.

[0102] Such as Figure 6As shown in the figure, after using the spot rotation compensation laser processing method of the present invention, taking the measurement of the spot rotation amount at the characteristic position according to m = 21 (20 equal divisions of each side length of the entire processing area) as an example, during laser processing, the rotation of the spot generated at the edge of the 210mm * 210mm area is corrected from about 3.6° to less than 0.2°, the corresponding sawtooth linearity < 1.5μm, and the flatness of the line processing is good, which is beneficial to the subsequent etching process and has a good processing effect.

[0103] Therefore, the rotation compensation laser processing method and system of the present invention are applicable to the processing of square spots (or other non-circular spots) and can control the rotation amount of the spot within the error range.

[0104] It should be known that the spot rotation compensation laser processing method and the rotation compensation laser processing system of the present invention are described by taking a square spot as an example. However, the present invention is not limited to square spots and can be applied to other non-circular spots, such as rectangular spots, linear spots, elliptical spots, etc.

[0105] It is easy for those skilled in the art to understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A laser processing method for spot rotation compensation, characterized in that, It includes the following steps: S1: Complete the spot debugging and adjust the shaping device to the standard position; S2: Select several characteristic positions within the entire processing area. At the characteristic positions, use a laser to process several light spots on the calibration object and measure the spot rotation amount corresponding to each light spot; S3: According to the spot rotation amount corresponding to the light spots at each characteristic position, fit the relationship between the compensation angle of the shaping device and the processing position coordinates of the entire processing area; S4: According to the relationship between the compensation angle of the shaping device and the processing position coordinates of the entire processing area, control the shaping device to rotate to compensate for the spot rotation amount and perform laser processing; The spot is a non-circular spot; In step S1, adjusting the shaping device to the standard position includes: initially adjusting the angle of the shaping device so that the spot at the center of the processing area has no rotation; In step S2, each side length of the entire processing width is equally divided into m - 1 parts, where m ≥ 3, and m * m symmetric characteristic positions are selected, and the coordinates of each characteristic position are (x i , y j ); Taking the straight line formed by the light spots when the shaping device does not rotate as the reference line of the line processing direction, measure the rotation angle θ(x i , y j ) of the reference line of the light spot rotation direction and the reference line of the line processing direction at each characteristic position, where i = 1, 2, 3…m, j = 1, 2, 3…m.

2. The laser processing method for spot rotation compensation according to claim 1, wherein The shape of the spot is rectangular, elliptical or linear.

3. The laser processing method for spot rotation compensation according to claim 1 or 2, characterized in that Take the straight line connected by the lowest or highest points of the light spots as the reference line for the line processing direction; or, take the standard straight line connected by the centers of the light spots as the reference line for the line processing direction; For a rectangular spot, take the bottom side length or the top side length direction of the light spot as the reference line for the rotation direction; for an elliptical spot or a linear spot, take the direction of the vertex connection as the reference line for the rotation direction.

4. The laser processing method for spot rotation compensation according to claim 3, characterized in that, The light spot rotation amount is positive when turning from the line processing direction reference line to the rotation direction reference line, and the compensation angle corresponding to the shaping device is -θ(x i , y j ); Alternatively, taking the rotation from the reference line of the wire processing direction to the reference line of the rotation direction as negative, the compensation angle corresponding to the shaping device is +θ(x i ,y j ).

5. The spot rotation compensation laser processing method according to any one of claims 1, 2 or 4, characterized in that The fitting method is as follows: For any position within the processing width ( ), based on its distances from the four closest feature positions, the rotation amount of the light spot is calculated according to the weights , as shown in Equation (1): ……Formula (1) Among them, , , , , are respectively the four feature positions closest to the distance position ( ). , , are the spot rotation amounts of a, b, c, d are respectively the perpendicular distances from the position ( ) to the pairwise connections of the four feature positions, and L is the distance between the pairwise connections of adjacent feature positions.

6. The laser processing method for spot rotation compensation according to any one of claims 1, 2 or 4, characterized in that The fitting method is: According to the measured spot rotation amounts corresponding to each characteristic position, establish the relationship between the spot rotation amount on the entire processing area and the characteristic positions, and through the spot rotation amount and the characteristic positions, fit the relationship between the spot rotation amount and the position at any position on the entire processing area, as shown in Equation (2): …… formula (2) Substitute a 1. b 1. c 1. d 1 and the characteristic position coordinates (x i , y j ) into the calculation one by one until the numerical values of the rotation amounts of all the characteristic position light spots calculated are equal to the measured numerical values or reach the set error, so as to determine the coefficient a 1. b 1. c 1. d 1; For the light spot at non-characteristic positions, substitute a 1, b 1, c 1, d 1 and its position coordinates into Equation (2) to obtain the corresponding light spot rotation amount.

7. The laser processing method for spot rotation compensation according to claim 4, wherein The shaping device is fixed on the spectacle frame, and at the same time, the spectacle frame is fixed on the rotating motor. Under the action of the rotating motor, the shaping device rotates along the direction perpendicular to its incident and outgoing light directions; the compensation angle of the shaping device is adjusted by rotating the shaping device by -θ(x i , y j ) or +θ(x i , y j ) angles in the direction perpendicular to the incident laser direction.

8. A spot rotation compensation laser processing system for the spot rotation compensation laser processing method according to any one of claims 1-7, characterized in that, It includes a laser, a shaper assembly, a galvanometer scanner and a field lens arranged in sequence along the optical path, and also includes a controller; wherein, The shaper assembly includes a shaping device, which is fixed on the mirror frame, and at the same time the mirror frame is fixed on the hollow rotary motor. Under the rotation of the hollow rotary motor, the shaping device rotates perpendicular to its incident and exit light directions; The controller is electrically connected to the hollow rotary motor and the galvanometer scanner, so as to control the galvanometer scanner to process according to the set speed and path, and at the same time control the hollow rotary motor to rotate by the corresponding rotation amount at a specific processing position for angle compensation.

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