Laser beam splitting processing equipment

Abstract

The present invention provides a laser beam splitting processing device, and relates to the field of laser processing technology. The laser beam splitting processing device includes a laser, a diffraction beam splitter and an f-sinθ focusing lens group; the diffraction beam splitter receives the laser beam emitted by the laser and divides it into multiple sub-beams; the f-sinθ focusing lens group receives multiple sub-beams, focuses the sub-beams, and controls the positions of the sub-beams on the focal plane; the sub-beams of each level output by the diffraction beam splitter satisfy the Bragg equation: 2dsinθ=mλ, and the f-sinθ focusing lens group satisfies the imaging relationship: h=f*sinθ, d is the period constant of the beam splitter, θ is the incident beam angle, m is the diffraction beam order, λ is the laser wavelength, h is the focus spot position; f is the focal length of the f-sinθ focusing lens group. The device realizes precision multi-beam processing in the process of cooperating with a motor for processing, and maintains the distance between the focus spots of each sub-beam with good accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing, and in particular to a laser beam splitting processing device. Background Art

[0002] In the field of laser processing technology, f-θ lenses are often used in conjunction with galvanometers for processing, or focusing lenses are used in conjunction with motors for processing. During these processing processes, especially when focusing lenses are used in conjunction with motors for processing, the processing speed is slow for processing scenarios that require repeated marking.

[0003] In order to increase the processing speed, the diffraction beam splitting-focusing method is often used to achieve multi-beam synchronous processing. For conventional focusing lenses, the point spacing (h m -h m-1 ) is a quantity related to the diffraction order m. When the angle θ between the incident light beam and the axis of the focusing lens group is very small, the spacing between adjacent focused light spots is approximately equal; however, as the angle θ increases, the point spacing will have a large deviation; and this type of focusing lens generally does not have flat field properties, and the focal plane is an arc-shaped surface. There are also standard f-θ lenses for focusing. Although this type of lens has a large field of view and good flat field properties, the point spacing is also a quantity related to the diffraction order m. When the angle θ is very small, the effect of m is not obvious, and the spacing between adjacent focused light spots is approximately equal; however, as the angle θ increases, the effect of m becomes increasingly obvious, and the point spacing will have a large deviation.

[0004] It can be seen that the lenses currently used in laser processing are mainly ordinary focusing lenses and standard f-θ lenses. When used for multi-beam splitting, the line spacing error is too large and cannot meet the needs of precision multi-beam processing. Summary of the invention

[0005] The purpose of the present invention includes providing a laser beam splitting processing device to realize precise multi-beam processing and maintain the distance between the focusing spots of each sub-beam with good accuracy.

[0006] The embodiments of the present invention can be implemented as follows:

[0007] The present invention provides a laser beam splitting processing device, the laser beam splitting processing device comprising:

[0008] A laser for emitting a laser beam;

[0009] A diffraction beam splitter, used for receiving a laser beam and splitting the laser beam into a plurality of sub-beams;

[0010] The f-sinθ focusing lens group is used to receive multiple sub-beams, focus the sub-beams, and control the positions of the sub-beams on the focal plane;

[0011] Among them, the sub-beams of each level output by the diffraction beam splitter satisfy the Bragg equation: 2dsinθ=mλ, and the f-sinθ focusing lens group satisfies the imaging relationship: h=f*sinθ, wherein d is the period constant of the beam splitter, θ is the angle between the incident light beam and the axis of the f-sinθ focusing lens group, m is the order of the diffraction light beam, λ is the laser wavelength used, h is the distance between the focused light spot and the axis of the f-sinθ focusing lens group; and f is the focal length of the f-sinθ focusing lens group.

[0012] The beneficial effects of the laser beam splitting processing equipment provided by the embodiment of the present invention include:

[0013] 1. Because the sub-beams of each level output by the diffraction beam splitter satisfy the Bragg equation: 2dsinθ=mλ, h and θ satisfy h=f*sinθ, so under this imaging relationship, h and the diffracted beam order m satisfy: h m =f*sinθ m =f*sin(arcsinmλ / 2d)=f*mλ / 2d, so the point spacing d=h m -h m-1 =fλ / 2d, which is a constant independent of the diffraction beam order m and θ. It means that as the incident beam order increases, the distance between the focused spots remains equal, and a good spot spacing accuracy can be maintained. The focused spots have consistent focusing effect and focusing size, and the requirements of precision multi-beam processing are met during laser multi-beam processing.

[0014] 2. The f-sinθ focusing lens group is used in combination with a diffraction beam splitter for laser beam splitting processing. The optical system has the characteristics of high integration, compact structure, stability, high processing accuracy and high processing efficiency.

[0015] In an optional embodiment, the f-sinθ focusing lens group includes any one of a scanning field lens, a spherical focusing lens group, and an aspherical lens group.

[0016] In an optional embodiment, the f-sinθ focusing lens group includes three or four spherical lenses.

[0017] In an optional embodiment, the f-sinθ focusing lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence, the first lens is a negative biconcave lens, the second lens is a negative meniscus lens with the concave surface facing the incident side, the third lens is a positive biconvex lens, and the fourth lens is a positive biconvex lens.

[0018] In this way, the optical power distribution of the four lenses of the f-sinθ focusing lens group is: negative, negative, positive, positive. Such an optical power distribution can better correct the field curvature of the system, so that the focusing surface has better flatness, which is beneficial to material processing. Moreover, the concave surface of the second lens faces the incident direction, which is conducive to introducing barrel distortion, thereby correcting the entire field distortion.

[0019] In an optional embodiment, the laser beam splitting processing equipment further includes:

[0020] The laser beam shaper is arranged between the laser and the diffraction beam splitter.

[0021] In an optional embodiment, the laser beam splitting processing equipment further includes:

[0022] The spacing adjustment module is arranged between the diffraction beam splitter and the f-sinθ focusing lens group, and is used to adjust the spacing between the multiple sub-beams.

[0023] In this way, the spacing between the multiple sub-beams can be flexibly adjusted through the spacing adjustment module. The spacing adjustment module can be a lens group with a fixed magnification, a lens group with a variable magnification, or a programmable spatial light modulator.

[0024] In an optional embodiment, the spacing adjustment module includes any one of a fixed-magnification lens group, a variable-magnification lens group, or a programmable spatial light modulator.

[0025] In an optional embodiment, the laser beam splitting processing equipment further includes:

[0026] A beam expander is disposed between the laser and the diffraction beam splitter, and is used to adjust the beam diameter and divergence angle of the laser beam; and / or,

[0027] The filter mask plate is arranged on the light-emitting side of the f-sinθ focusing lens group, and the filter mask plate is used for filtering the laser beam.

[0028] The beam expander can be adjusted manually or electrically. After the laser beam emitted by the laser is properly expanded by the beam expander, it is divided into the required sub-beams by the diffraction beam splitter. These sub-beams pass through the spacing adjustment module and are then focused to the focal plane by the f-sinθ focusing lens group for processing.

[0029] In an optional embodiment, the laser includes any one of a solid laser, a gas laser, a semiconductor laser, a dye laser or a fiber laser, and the diffraction beam splitter is a diffraction optical element or a programmable spatial light modulator.

[0030] Of course, the laser can be a single-mode laser or a multi-mode laser. The minimum number of beam splitters of a diffraction beam splitter is 1, and the maximum number of beam splitters depends on the number required for the specific processing.

[0031] In an optional embodiment, the maximum field of view of the f-sinθ focusing lens group is ±25°, the beam splitting number range of the diffraction beam splitter is greater than 1, and the focal length f of the f-sinθ focusing lens group ranges from 100 mm to 500 mm.

[0032] In an optional embodiment, the distance difference between two adjacent sub-beams in the multiple sub-beams does not exceed 0.01 mm; and / or the interval range between two adjacent sub-beams is: 0.5 mm to 20 mm; and / or the parallelism deviation of the multiple sub-beams is less than 0.02°; and / or the energy difference between at least two sub-beams does not exceed 10%.

[0033] Of course, the distance between two adjacent sub-beams can also be determined according to the interval required for specific processing. The size of the multiple laser spots of the multiple sub-beams on the substrate to be processed depends on the specific processing requirements, and can be square or circular; the minimum size of the laser spot is the diffraction limit of the f-sinθ focusing lens group.

[0034] In an optional embodiment, the laser beam splitting processing equipment further includes:

[0035] A processing platform, used for carrying a substrate to be processed;

[0036] The motion platform is connected to the processing platform and is used to drive the processing platform to move relative to the f-sinθ focusing lens group.

[0037] In an optional embodiment, the maximum absolute position deviation of the multiple laser spots of the multiple sub-beams on the substrate to be processed does not exceed 0.06 mm, and the relative position deviation does not exceed 0.07%. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 A schematic diagram of the composition of a laser beam splitting processing device provided in an embodiment of the present invention;

[0040] Figure 2 A comparison of the absolute errors of the existing f-θ lens and the laser beam splitting processing equipment provided by the embodiment of the present invention;

[0041] Figure 3 A comparison of relative errors between an existing f-θ lens and a laser beam splitting processing device provided by an embodiment of the present invention;

[0042] Figure 4 Schematic diagram of the distribution of spot position error and line spacing error in Example 1;

[0043] Figure 5 Schematic diagram of the absolute position error and line spacing error distribution of the light spot in Example 2;

[0044] Figure 6 Schematic diagram of the absolute position error and line spacing error distribution of the light spot in Example 3;

[0045] Figure 7 A schematic structural diagram of an f-sinθ focusing lens assembly according to an embodiment of the present invention;

[0046] Figure 8 This is a light path diagram of an f-sinθ focusing lens group in accordance with an embodiment of the present invention when used in conjunction with a diffraction beam splitter.

[0047] Icon: 100-laser beam splitting processing equipment; 1-laser; 2-beam expander; 3-reflector; 4-diffraction beam splitter; 5-distance adjustment module; 6-f-sinθ focusing lens group; 61-first lens; 62-second lens; 63-third lens; 64-fourth lens; 65-protective glass; 66-aperture surface. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0049] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0051] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0052] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0053] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0054] Please refer to Figure 1 This embodiment provides a laser beam splitting processing device 100, which includes a laser 1, a beam expander 2, a reflector 3, a diffraction beam splitter 4, a spacing adjustment module 5 and an f-sinθ focusing lens group 6 arranged in sequence along the incident direction of the laser beam.

[0055] The laser 1 is used to emit a laser beam. The laser 1 is a solid laser, a gas laser, a semiconductor laser, a dye laser or a fiber laser. Of course, the laser 1 can be a single-mode laser or a multi-mode laser.

[0056] The beam expander 2 is used to adjust the beam diameter and divergence angle of the laser beam. The beam expander 2 can be adjusted manually or electrically.

[0057] The reflecting mirror 3 is used to reflect the laser light beam expanded by the beam expander 2 to the diffraction beam splitter 4 .

[0058] The diffraction beam splitter 4 is used to receive the laser beam and split the laser beam into multiple sub-beams. The laser beam is split into the required sub-beams by the diffraction beam splitter 4. The diffraction beam splitter 4 is a diffraction optical element or a programmable spatial light modulator. The minimum number of beam splitting of the diffraction beam splitter 4 is 1, and the maximum number of beam splitting depends on the number required for the specific processing.

[0059] Among them, the sub-beams of each level output by the diffraction beam splitter 4 satisfy the Bragg equation: 2dsinθ=mλ, where d is the period constant of the beam splitter, θ is the angle between the incident beam and the axis of the f-sinθ focusing lens group 6, m is the order of the diffraction beam, and λ is the laser wavelength used.

[0060] The f-sinθ focusing lens group 6 is used to receive multiple sub-beams, focus the sub-beams, and control the positions of the sub-beams on the focal plane, that is, to control each sub-beam to satisfy the relationship h=f*sinθ. The sub-beams are divided into the required sub-beams by the diffraction beam splitter 4, pass through the spacing adjustment module, and are then focused to the focal plane by the f-sinθ focusing lens group 6 for processing.

[0061] The f-sinθ focusing lens group 6 satisfies the imaging relationship: h=f*sinθ, where h is the distance between the focused light spot and the axis of the f-sinθ focusing lens group 6 ; and f is the focal length of the f-sinθ focusing lens group 6 .

[0062] The laser beam shaper is arranged between the laser 1 and the diffraction beam splitter 4, and is used to modulate the laser phase to obtain a light spot of a desired size and shape.

[0063] The laser beam shaper requires that the incident laser beam is single-mode and the diffraction factor of the laser beam is M. 2 <1.5; the laser beam shaper requires that the incident beam diameter is a certain value between 1mm and 15mm, preferably 4mm to 10mm; the beam diameter error is less than ±10%, preferably less than ±5%. By using diffraction beam splitting processing, the field stop position of the laser beam can be strictly coincident with the field stop surface of the f-sinθ lens, thereby avoiding deformation, rotation and other distortion phenomena of the light spot. The square light spot obtained based on the f-sinθ lens combined with the laser beam shaper has uniform energy distribution, square shape, no distortion, high spot position accuracy and high processing efficiency.

[0064] The spacing adjustment module 5 is arranged between the diffraction beam splitter 4 and the f-sinθ focusing lens group 6, and the spacing adjustment module 5 is used to adjust the spacing between the multiple sub-beams. In this way, the spacing between the multiple sub-beams can be flexibly adjusted through the spacing adjustment module 5, and the spacing adjustment module 5 can be a lens group with a fixed magnification, a lens group with a variable magnification, or a programmable spatial light modulator.

[0065] The distance difference between two adjacent sub-beams does not exceed 0.01 mm. The interval between two adjacent sub-beams depends on the interval required for specific processing. Preferably, the interval between two adjacent sub-beams is in the range of 0.5 mm to 20 mm, the parallelism deviation of multiple sub-beams is less than 0.02°, and the energy difference between at least two sub-beams does not exceed 10%.

[0066] Because the sub-beams of each level output by the diffraction beam splitter 4 satisfy the Bragg equation: 2dsinθ=mλ, and the relationship between the focus spot position h and the incident beam angle θ satisfies h=f*sinθ, so under this imaging relationship, the relationship between the focus spot position h and the diffracted beam order m satisfies: h m =f*sinθm =f*sin(arcsinmλ / 2d)=f*mλ / 2d, so the point spacing d=h m -h m-1 =fλ / 2d, which is a constant independent of the diffraction beam order m and θ. It means that as the incident beam order increases, the distance between the focused spots remains equal, and a good spot spacing accuracy can be maintained. The focused spots have consistent focusing effect and focusing size, and the requirements of precision multi-beam processing are met during laser multi-beam processing.

[0067] Moreover, by using the above-mentioned f-sinθ focusing lens group 6 in conjunction with the diffraction beam splitter 4 to perform laser beam splitting processing, the optical system has the characteristics of high integration, compact structure, stability, high processing accuracy and high processing efficiency.

[0068] The maximum field of view of the f-sinθ focusing lens group 6 is ±25°, and the focal length f of the f-sinθ focusing lens group 6 ranges from 100 mm to 500 mm.

[0069] The f-sinθ focusing lens group 6 includes one of a scanning field lens, a spherical focusing lens group, and an aspherical lens group. The f-sinθ focusing lens group 6 includes three or four spherical lenses that are sequentially spaced apart.

[0070] Specifically, Figure 7 and Figure 8 As shown, the f-sinθ focusing lens group 6 may include a first lens 61, a second lens 62, a third lens 63, a fourth lens 64 and a protective glass 65 which are spaced in sequence. The first lens 61 is a negative biconcave lens, the second lens 62 is a negative meniscus lens with the concave surface facing the incident side, the third lens 63 is a positive biconvex lens, and the fourth lens 64 is a positive biconvex lens. Specifically, the laser beam is incident from the aperture surface 66, and passes through the first lens 61, the second lens 62, the third lens 63, the fourth lens 64 and the protective glass 65 in sequence. In this way, the optical power distribution of the four lenses of the f-sinθ focusing lens group 6 is: negative negative positive positive. Such an optical power distribution can better correct the field curvature of the system, so that the focusing surface has better flatness, which is beneficial to material processing. Moreover, the concave surface of the second lens 62 faces the incident direction, which is conducive to introducing barrel distortion, thereby correcting the entire field distortion.

[0071] The first lens 61 and the third lens 63 are made of optical glass, preferably K9 optical glass. The second lens 62 and the fourth lens 64 are made of quartz glass, preferably fused quartz glass (F_SILICA). These materials can not only meet the design requirements, but also have low cost.

[0072] The focal length f of the f-sinθ lens satisfies the following structural relationship: -0.9 < f1 / f < -0.5, -1.5 < f2 / f < -0.9, 8 < f3 / f < 1.3, 5 < f4 / f < 1.1, where f1 is the focal length of the first lens 61, f2 is the focal length of the second lens 62, f3 is the focal length of the third lens 63, and f4 is the focal length of the fourth lens 64. Such a distribution of optical power and material selection can better correct the field curvature of the system, making the focusing plane have better flatness.

[0073] Preferably, f1 / f = -0.69, f2 / f = -1.14, f3 / f = 1.11, f4 / f = 0.86. The processing effect and accuracy are better at this focal length ratio.

[0074] Among them, the first lens 61, the second lens 62, the third lens 63, and the fourth lens 64 are all spherical mirrors or at least one of them is an aspherical mirror. Preferably, they are all spherical mirrors, and the lens cost is lower.

[0075] To verify that the design of the f-sinθ lens provided in this embodiment meets the requirements, this embodiment provides the following embodiments of the specific structural design of the f-sinθ lens.

[0076] The design parameters of the f-sinθ lens in one of the embodiments are as follows:

[0077] The designed focal length f of the f-sinθ lens is 350 mm. The first lens 61, the second lens 62, the third lens 63, and the fourth lens 64 are all spherical mirrors. The wavelength of the incident laser beam is 532 nm, the diameter of the incident beam is 11 mm, and the full field of view of the f-sinθ lens reaches the diffraction limit. The specific structural design parameters of the f-sinθ lens are as follows, where the unit of the radius of curvature, the central thickness, and the air spacing is mm, and the air spacing represents the distance between this element and the subsequent element:

[0078]

[0079] The f-sinθ lens is designed with the above structural parameters, so that the focal length f of the f-sinθ lens satisfies the following structural relationship: f1 / f = -0.69, f2 / f = -1.14, f3 / f = 1.11, f4 / f = 0.86, which can better correct the field curvature of the system and make the focusing plane have better flatness.

[0080] In Figure 7 and Figure 8 the incident laser beam is diffracted and split into multiple sub-beams. Through the f-sinθ lens designed in this application, all the multiple sub-beams satisfy the relationship of h = f * sinθ.

[0081] The laser beam splitting processing equipment 100 may also include a filter mask plate (not shown in the figure), a processing platform (not shown in the figure) and a motion platform (not shown in the figure). The filter mask plate is arranged on the light-emitting side of the f-sinθ focusing lens group 6, and the filter mask plate is used to filter the laser beam. The processing platform is used to carry the substrate to be processed. The motion platform is connected to the processing platform and is used to drive the processing platform to move relative to the f-sinθ focusing lens group 6.

[0082] The size of the multiple laser spots of the multiple laser beams on the substrate to be processed depends on the specific processing requirements, and can be square or circular; the minimum size of the laser spot is the diffraction limit of the f-sinθ focusing lens group 6. The maximum absolute position deviation of the multiple laser spots of the multiple sub-beams on the substrate to be processed does not exceed 0.06mm, and the relative position deviation does not exceed 0.07%.

[0083] See also Figure 2 and Figure 3 , Figure 2 The horizontal axis is the field of view, in degrees, and the vertical axis is the absolute error, in μm. Figure 3 The horizontal axis is the field of view angle in degrees, and the vertical axis is the relative error.

[0084] When using the existing f-θ lens with a standard focal length of 330mm for multi-beam processing and the beam splitting angle reaches ±16°, the corresponding processing format is 184mm*184mm, and the absolute error of the focus position at the edge of the format is about 1400μm, and the relative error is about 1.6%.

[0085] When laser multi-beam processing is performed using the laser beam splitting processing equipment 100 with a standard focal length of 350 mm provided in this embodiment, when the beam splitting angle reaches ±15.5°, the distance between the two outermost light spots is 187 mm, the absolute error of the focus position at the edge of the format is about 60 μm, and the relative error is about 0.07% (the error depends on the distortion of the f-sinθ focusing lens group 6).

[0086] In order to verify the technical effect of the laser beam splitting processing device 100 provided by this embodiment, this embodiment provides the following specific application examples of the laser beam splitting processing device 100.

[0087] Example 1

[0088] It is used for PERC process of solar cells with a size of 182mm*182mm, with 182 lines and a spacing of 1mm. The laser beam emitted by the laser 1 is expanded by the beam expander 2, split by the diffraction beam splitter 4, and finally incident on the f-sinθ focusing lens group 6 to be focused on the focal plane.

[0089] The wavelength of the incident laser is 532nm, and the beam diameter of the laser beam after expansion is 11mm; the diffraction beam splitter 4 makes the angle between the +1 and -1 order diffraction beams 0.1637°, the corresponding focusing spot interval is 1mm, the total number of beam splitting is 182 beams, and the corresponding maximum diffraction order is ±181. The connecting line of these sub-beams is perpendicular to the direction of table movement, and the power difference between each sub-beam is less than 5%; the focal length of the f-sinθ focusing lens group 6 is 350mm, the designed maximum incident beam diameter is 14mm, and the maximum field angle is ±15.5°. The spacing adjustment module 5 set between the diffraction beam splitter 4 and the f-sinθ focusing lens group 6 is set to 1.0x.

[0090] The focused spot size is 25μm, the spot spacing parallel to the direction of table movement is 30μm, the corresponding laser frequency is 20kHz, the total incident laser pulse energy is 5mJ, and the total power is 100W; during processing, the processing table vacuum absorbs the silicon wafer and passes through the focal plane at a speed of 1.0m / s. The processing time is about 0.18s, which is 64% less than the galvanometer processing process.

[0091] The position error (absolute error) and spacing error distribution of the light spot are as follows: Figure 4 shown. Figure 4 In the figure, the horizontal axis represents the number of the light spot, and the vertical axis represents the error size, in μm. Figure 4 It can be seen that the maximum overall spot position error is 13μm, the line spacing error is less than 2μm, and the overall graphic accuracy error is less than 1μm, which meets the PERC process requirements.

[0092] Comparative Example 1

[0093] The conventional f-θ lens and the galvanometer scanning processing scheme are used for galvanometer scanning processing. The galvanometer processing speed is 70m / s, the laser power is 50W, the total number of scribing lines is 182, each line is 182mm long, and the single piece takes about 0.5s. During this processing, the galvanometer needs to be tediously calibrated so that the system accuracy gradually meets the requirements. As the processing time goes by, the galvanometer has a certain degree of accuracy drift, which requires regular calibration and maintenance. This processing process takes a long time to debug and has low processing efficiency.

[0094] Example 2

[0095] Used for scribing of 2000mm*1200mm sized perovskite solar cells. The scribing direction is parallel to the short side, the interval is 10mm, the total number of scribing lines is 192, and the absolute scribing accuracy is required to be better than 15μm, and the line spacing accuracy is better than 10μm.

[0096] DOE was used to perform a single 16-beam splitting process and 12 continuous splicings to achieve a total number of 192 lines. The light beam emitted by the laser 1 was expanded by the beam expander 2, split by the diffraction beam splitter 4, and finally incident on the f-sinθ focusing lens group 6 to be focused on the focal plane.

[0097] The wavelength of the incident laser is 532nm, and the beam diameter after the laser beam is expanded is 8mm; the diffraction beam splitter 4 makes the angle between the +1 and -1 order diffraction beams 1.6371°, and the corresponding focusing spot interval is 10mm. The number of beam splitting in a single processing is 16 beams, and the corresponding maximum diffraction order is ±15. The connecting line of these sub-beams is perpendicular to the direction of table movement, and the power difference between each sub-beam is less than 5%; the focal length of the f-sinθ focusing lens group 6 is 350mm, the designed maximum incident beam diameter is 14mm, and the maximum field angle is ±15.5°. The spacing adjustment module 5 set between the DOE and the f-sinθ focusing lens group 6 is set to 1.0x.

[0098] The focused spot size is 40μm, the spot spacing parallel to the direction of table movement is 30μm, the corresponding laser frequency is 50kHz, the total pulse energy of the incident laser is 100μJ, and the total power is 50W; during processing, the battery workpiece is installed on the processing platform and passes through the focal plane at a speed of 1.5m / s. A single pass takes about 1.5s and a total of 18s.

[0099] The position error and spacing error of the light spot are distributed as follows: Figure 5 shown. Figure 5 In the figure, the horizontal axis represents the number of the light spot, and the vertical axis represents the error size, in μm. Figure 5 It can be seen that the maximum absolute position error of the overall spot is 13μm, the line spacing error is less than 6μm, and the overall graphic accuracy error is less than 1μm, which meets the processing accuracy requirements.

[0100] Comparative Example 2

[0101] Conventional f-θ lenses are used for DOE beam splitting processing, and 8-beam processing is performed; the focused spot size is 40μm, the spot spacing is 30μm, the corresponding laser frequency is 50kHz, the total incident laser pulse energy is 50μJ, and the total power is 25W; during processing, the battery workpiece is installed on the processing platform and passes through the focal plane at a speed of 1.5m / s. A single pass takes about 1.5s, and the number of scribing times is 24. The total time is 36s. The absolute accuracy of scribing is worse than 300μm, and the line spacing accuracy is worse than 50μm; the number of scribing times is 24, and the workpiece passes through the focal plane at a speed of 1.5m / s. A single pass takes about 1.5s, and the total time is 36s. This solution has poor accuracy and is time-consuming, and does not meet the processing requirements of this type of battery.

[0102] Example 3

[0103] Used for scribing of 2000mm*1200mm sized perovskite solar cells. The scribing direction is parallel to the short side, the interval is 8mm, the total number of scribing lines is 240, and the absolute scribing accuracy is required to be better than 15μm, and the line spacing accuracy is better than 10μm.

[0104] DOE was used to perform a single 16-beam splitting process and 15 continuous splicings to achieve a total number of 240 lines. The light beam emitted by the laser 1 was expanded by the beam expander 2, split by the diffraction beam splitter 4, and finally incident on the f-sinθ focusing lens group 6 to be focused on the focal plane.

[0105] The wavelength of the incident laser is 532nm, and the beam diameter after the laser beam is expanded is 6.4mm; the diffraction beam splitter 4 makes the angle between the +1 and -1 order diffraction beams 1.6371°, and the corresponding focus spot interval is 10mm. The number of beam splitting in a single processing is 16 beams, and the corresponding maximum diffraction order is ±15. The connecting line of these sub-beams is perpendicular to the direction of table movement, and the power difference between each sub-beam is less than 5%; the focal length of the f-sinθ focusing lens group 6 is 350mm, the maximum incident beam diameter is designed to be 14mm, and the maximum field of view is ±15.5°. The spacing adjustment module 5 set between the DOE and the f-sinθ focusing lens group 6 is set to 1.25x, and the corresponding spot line spacing will be reduced from 10mm to 8mm.

[0106] The focused spot size is 40μm, the spot spacing parallel to the direction of table movement is 30μm, the corresponding laser frequency is 50kHz, the total pulse energy of the incident laser is 100μJ, and the total power is 50W; during processing, the battery workpiece is installed on the processing platform and passes through the focal plane at a speed of 1.5m / s. A single pass takes about 1.5s and a total time of 22.5s.

[0107] The position error and spacing error of the light spot are distributed as follows: Figure 6 shown. Figure 6 In the figure, the horizontal axis represents the number of the light spot, and the vertical axis represents the error size, in μm. Figure 6 It can be seen that the maximum absolute position error of the overall light spot is 12μm, the line spacing error is less than 5μm, and the overall graphic accuracy error is less than 1μm, which meets the processing accuracy requirements.

[0108] Comparative Example 3

[0109] Conventional f-θ lenses are used for DOE beam splitting processing, and 8-beam processing is performed; the focused spot size is 40μm, the spot spacing is 30μm, the corresponding laser frequency is 50kHz, the total incident laser pulse energy is 50μJ, and the total power is 25W; during processing, the battery workpiece is installed on the processing platform and passes through the focal plane at a speed of 1.5m / s. A single pass takes about 1.5s, and the number of scribing times is 30. The total time is 45s. The absolute accuracy of scribing is worse than 300μm, and the line spacing accuracy is worse than 50μm; the number of scribing times is 30, and the workpiece passes through the focal plane at a speed of 1.5m / s. A single pass takes about 1.5s, and the total time is 45s. This solution has poor accuracy and is time-consuming, and does not meet the processing requirements of this type of battery.

[0110] The beneficial effects of the laser beam splitting processing device 100 provided by the embodiment of the present invention include:

[0111] 1. Because the sub-beams of each level output by the diffraction beam splitter 4 satisfy the Bragg equation: 2dsinθ=mλ, the focus spot position h and the incident beam angle θ satisfy h=f*sinθ, so the point spacing: d=h m -h m-1 =fλ / 2d, which is a constant independent of the diffraction beam order m and θ. As the incident beam order increases, the distance between the focused spots remains equal, which can maintain a good spot spacing accuracy, thereby maintaining a high spacing accuracy and meeting the requirements of precision multi-beam processing;

[0112] 2. The f-sinθ focusing lens group 6 is used in combination with the diffraction beam splitter 4 to perform laser beam splitting processing. The optical system has the characteristics of high integration, compact structure, stability, high processing accuracy and high processing efficiency;

[0113] 3. A spacing adjustment module 5 is added so that the line spacing can be flexibly adjusted according to actual needs during laser processing.

[0114] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A laser beam splitting processing device, characterized in that: The laser beam splitting processing equipment includes: A laser (1) for emitting a laser beam; a diffraction beam splitter (4), configured to receive the laser beam and split the laser beam into a plurality of sub-beams; an f-sinθ focusing lens group (6) for receiving a plurality of sub-beams, focusing the sub-beams, and controlling the positions of the sub-beams on the focal plane; The sub-beams of each level output by the diffraction beam splitter (4) satisfy the Bragg equation: 2dsinθ=mλ, and the f-sinθ focusing lens group (6) satisfies the imaging relationship: h=f*sinθ, wherein d is the period constant of the beam splitter, θ is the angle between the incident light beam and the axis of the f-sinθ focusing lens group (6), m is the order of the diffracted light beam, λ is the wavelength of the laser used, h is the distance between the focused light spot and the axis of the f-sinθ focusing lens group (6), and f is the focal length of the f-sinθ focusing lens group (6).

2. The laser beam splitting processing equipment according to claim 1, characterized in that: The f-sinθ focusing lens group (6) comprises any one of a scanning field lens, a spherical focusing lens group, and an aspherical lens group.

3. The laser beam splitting processing equipment according to claim 1, characterized in that: The f-sinθ focusing lens group (6) includes three or four spherical lenses.

4. The laser beam splitting processing equipment according to claim 1, characterized in that: The f-sinθ focusing lens group (6) comprises a first lens, a second lens, a third lens and a fourth lens arranged in sequence, wherein the first lens is a negative biconcave lens, the second lens is a negative meniscus lens with a concave surface facing the incident side, the third lens is a positive biconvex lens, and the fourth lens is a positive biconvex lens.

5. The laser beam splitting processing equipment according to claim 1, characterized in that: The laser beam splitting processing equipment further comprises: A laser beam shaper is arranged between the laser (1) and the diffraction beam splitter (4).

6. The laser beam splitting processing equipment according to any one of claims 1 to 5, characterized in that: The laser beam splitting processing equipment further comprises: A spacing adjustment module (5) is provided between the diffraction beam splitter (4) and the f-sinθ focusing lens group (6), and the spacing adjustment module (5) is used to adjust the spacing between the plurality of sub-beams.

7. The laser beam splitting processing equipment according to claim 6, characterized in that: The spacing adjustment module (5) comprises any one of a fixed magnification lens group, a variable magnification lens group or a programmable spatial light modulator.

8. The laser beam splitting processing equipment according to claim 6, characterized in that: The laser beam splitting processing equipment further comprises: a beam expander (2), disposed between the laser (1) and the diffraction beam splitter (4), the beam expander (2) being used to adjust the beam diameter and divergence angle of the laser beam; and / or, A filter mask is arranged on the light-emitting side of the f-sinθ focusing lens group (6), and the filter mask is used to filter the laser beam.

9. The laser beam splitting processing equipment according to claim 1, characterized in that: The laser (1) comprises any one of a solid laser (1), a gas laser (1), a semiconductor laser (1), a dye laser (1) or a fiber laser (1), and the diffraction beam splitter (4) is a diffraction optical element or a programmable spatial light modulator.

10. The laser beam splitting processing equipment according to claim 1, characterized in that: The maximum field of view of the f-sinθ focusing lens group (6) is ±25°, the beam splitting number range of the diffraction beam splitter (4) is greater than 1, and the focal length f of the f-sinθ focusing lens group (6) ranges from 100 mm to 500 mm.

11. The laser beam splitting processing equipment according to claim 1, wherein: The distance difference between two adjacent sub-beams in the plurality of sub-beams does not exceed 0.01 mm; and / or, The interval between two adjacent sub-beams is in the range of 0.5 mm to 20 mm; and / or, The parallelism deviation of the plurality of sub-beams is less than 0.02°; and / or, The energy difference between at least two of the sub-beams does not exceed 10%.

12. The laser beam splitting processing equipment according to claim 1, characterized in that: The laser beam splitting processing equipment further comprises: A processing platform, used to carry the substrate to be processed; A motion platform is connected to the processing platform and is used to drive the processing platform to move relative to the f-sinθ focusing lens group (6).

13. The laser beam splitting processing equipment according to claim 1, characterized in that: The maximum absolute position deviation of the multiple laser spots of the multiple sub-beams on the substrate to be processed does not exceed 0.06 mm, and the relative position deviation does not exceed 0.07%.

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