Laser processing device and solar cell processing system

Abstract

The embodiment of the utility model provides a laser processing device and a solar cell processing system. The laser processing device comprises a laser used for emitting flat-topped light spots; the light beam shaping part is located on the light emitting side of the laser device, and the light beam shaping part comprises a closed opening part which is used for cutting flat-topped light spots emitted by the laser device; and the optical assemblies are located on the light emitting side of the light beam shaping part, the optical assemblies are used for forming focusing light spots, and the focusing light spots act on a workpiece to be machined.

Description

Technical Field

[0001] This application relates to the field of laser processing technology, and more specifically, to a laser processing apparatus and a solar cell processing system. Background Technology

[0002] Laser scribing is involved in the production process of thin-film solar cells. However, as a high-intensity energy processing method, laser scribing inevitably creates a heat-affected zone at the edge of the groove, accompanied by a material buildup effect (commonly known as a crater).

[0003] How to effectively control and reduce the width of the heat-affected zone while suppressing the height of the crater has become a pressing technical challenge in the industry.

[0004] In view of this, a new technical solution is needed to solve the above-mentioned technical problems. Utility Model Content

[0005] The purpose of this application is to provide a new technology solution for a laser processing device and a solar cell processing system.

[0006] In a first aspect, embodiments of this application provide a laser processing apparatus. The laser processing apparatus includes: a laser for emitting a flat-top laser spot;

[0007] A beam shaping section is located on the light-emitting side of the laser. The beam shaping section includes a closed opening, which is used to cut the flat-top beam spot emitted by the laser.

[0008] At least one set of optical components, the optical components being located on the light-emitting side of the beam shaping section, the optical components being used to form a focused light spot, the focused light spot acting on the workpiece to be processed.

[0009] Optionally, a metal sheet is provided on the edge of the closed opening, the metal sheet being formed with a blade, the blade facing the interior of the closed opening.

[0010] Optionally, the beam shaping section further includes an adjustment mechanism for adjusting the opening size of the closed opening.

[0011] Optionally, along the transmission direction of the laser beam, the optical assembly includes a phase retarder and a beam splitter arranged sequentially, and the optical assembly further includes a focusing lens group located in the reflection path of the beam splitter;

[0012] The phase delay plate is used to change the polarization direction of polarized light;

[0013] The beam splitter is used to split a beam of light into two beams, and the beam splitter is used to reflect one of the two beams and transmit the other of the two beams.

[0014] The focusing lens group is used to receive the light reflected by the beam splitter and focus the light onto the workpiece.

[0015] Optionally, the phase delay plate is a half-wave plate, which is configured to be rotatable.

[0016] Optionally, a beam-splitting film is disposed on the surface of the beam-splitting element near the phase retardation plate.

[0017] Optionally, the surface of the beam splitter facing away from the phase retarder is provided with an anti-reflection film.

[0018] Optionally, the laser processing apparatus includes at least two sets of optical components, which are arranged sequentially along the transmission direction of the laser emission spot; in two adjacent sets of optical components, the phase delay plate in the downstream optical component is used to receive the light transmitted by the beam splitter in the upstream optical component.

[0019] Optionally, the laser processing apparatus further includes a collimating element located between the beam shaping section and the optical components.

[0020] Optionally, the collimating element is a relay lens assembly.

[0021] Optionally, the laser processing apparatus further includes a mirror assembly located between the beam shaping section and the collimating element.

[0022] Secondly, embodiments of this application also provide a solar cell processing system. The solar cell processing system includes the laser processing apparatus as described in the first aspect.

[0023] According to an embodiment of this application, the laser processing apparatus includes a laser for directly emitting a flat-top beam, a beam shaping unit for cutting the flat-top beam, and an optical component for focusing the cut flat-top beam. The laser processing apparatus provided in this application embodiment can reduce crater and heat-affected zone defects and improve processing effect.

[0024] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0026] Figure 1 The diagram shown is a structural schematic of the laser processing apparatus provided in an embodiment of this application.

[0027] Figures 2a-2b The image shows the overall morphology and energy distribution of the laser spot at 0m from the laser exit.

[0028] Figures 3a-3b The image shows the overall morphology and energy distribution of the laser spot at a distance of 3m from the laser exit point.

[0029] Figures 4a-4b The diagram shows the overall morphology and energy distribution of the emitted beam from the beam shaping section.

[0030] Figure 5 The diagram shown is a schematic of the beam shaping section.

[0031] Figures 6a-6b The diagram shows the distribution of the focused spot and the energy distribution of the first channel.

[0032] Figures 7a-7b The diagram shows the distribution of the focused spot and the energy distribution of the 6th channel.

[0033] Figures 8a-9b The image shows the effect and energy distribution of the focused spot ±0.2mm in the first channel.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. Laser; 2. Beam shaping section; 20. Closed opening section; 21. First movable section; 22. Second movable section; 23. Third movable section; 24. Fourth movable section; 25. Adjustment mechanism; 3. Optical assembly; 31. Phase retarder; 32. Beam splitter; 33. Focusing lens group; 4. Collimating element. Detailed Implementation

[0036] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0037] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0038] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0039] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0040] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0041] Solar cells are mainly divided into two categories: thin-film solar cells and conventional solar cells (i.e., crystalline silicon solar cells). Laser scribing is an indispensable step in the manufacturing process of both types of solar cells. Whether producing thin-film or crystalline silicon solar cells, the choice between multi-channel or single-channel laser processing technology depends on specific production needs and efficiency requirements. In actual production, multi-channel laser processing technology is often more widely used to achieve higher production efficiency and meet the large market demand for solar cells.

[0042] Currently, achieving flat-top laser distribution typically relies on diffractive optical elements (DOEs). DOEs have relatively strict requirements on the quality of the incident laser beam, generally requiring M... 2 The value is no greater than 1.3 (M) 2 The factor describes the quality of the laser beam.

[0043] The traditional application method is to use a DOE with a focusing lens. This method is only suitable for single-path processing scenarios, but the processing capability of a single-path is difficult to meet the actual production capacity requirements.

[0044] In pilot and mass production lines for solar cells, the number of laser processing heads needs to be increased to 6 to 24 to improve processing efficiency. This necessitates the use of beam splitting schemes to achieve multi-path processing. However, multiple beam splitting leads to a decrease in laser beam quality. When this degraded laser beam is then used for shaping via a DOE (Device Executioner), the shaping effect is significantly reduced, resulting in poor scribing quality and inconsistent multi-path performance.

[0045] Therefore, this application provides a laser processing apparatus that, while meeting processing requirements, reduces crater and heat-affected zone defects and improves processing results.

[0046] Reference Figure 1The laser processing apparatus includes a laser 1, a beam shaping section 2, and at least one set of optical components 3. The laser 1 emits a flat-top beam. The beam shaping section 2 is located on the light-emitting side of the laser 1 and includes a closed opening 20 for cutting the flat-top beam emitted by the laser 1. At least one set of optical components 3 is located on the light-emitting side of the beam shaping section 2 and is used to form a focused beam that acts on the workpiece.

[0047] In other words, in this embodiment of the application, the laser processing apparatus mainly includes a laser 1, a beam shaping unit 2, and at least one set of optical components 3. The various components of the laser processing apparatus will be described in detail below.

[0048] Traditional lasers, such as Gaussian beam lasers, typically output beams that follow a Gaussian distribution, meaning the intensity peaks at the center and gradually decreases towards the edges, forming a Gaussian spot. This non-uniform energy distribution often leads to undesirable phenomena during laser scribing operations, such as heat-affected zones and material buildup (commonly known as the crater effect) on both sides of the groove.

[0049] To address this issue, existing technologies employ solutions such as the πShaper fiber laser collimating flat-top beam shaper, aiming to shape Gaussian light or beams with similar Gaussian distributions into flat-top beams. However, these beam shaping systems are quite complex, typically comprising multiple components including a laser, a diffractive optical element (DOE), and a focusing mirror. To ensure a high-quality flat-top beam, the relative positions of these components must be precisely adjusted, which undoubtedly increases the system's complexity and operational difficulty.

[0050] It is particularly noteworthy that in multi-path laser processing schemes, the quality of the laser beam will decrease after multiple splits. If a diffractive optical element (DOE) is then used for shaping, it is often difficult to obtain an ideal shaping effect, resulting in poor scribing results and poor consistency between the multiple optical paths.

[0051] Based on this, in this embodiment, the laser processing apparatus includes a laser 1, which is a laser capable of emitting a flat-top beam. That is, in this embodiment, the laser 1 can directly emit a flat-top beam. Compared to existing technologies, this avoids the complex beam shaping process and the many problems it causes. For example, the laser 1 can be an INNO-SLAB slab laser 1, or it can be an all-fiber laser 1.

[0052] Taking the INNO-SLAB slab laser 1 as an example, the laser spot output by the laser 1 can be customized as a flat-topped square spot. This embodiment does not limit the shape of the flat-topped spot emitted by the laser 1; the shape of the flat-topped spot includes, but is not limited to, a square. For example, the shape of the flat-topped spot can also be circular, rectangular, or linear, etc.

[0053] Reference Figure 2a and Figure 2b The overall morphology of the laser spot at 0m from laser exit point 1 is shown in the figure below. Figure 2a As shown in Figure 2b, the energy distribution of the laser spot in the X direction at 0m from the laser 1 exit is shown in Figure 2b.

[0054] Reference Figure 3a and Figure 3b The overall morphology of the laser spot at 3m from the laser exit point 1 is shown in the figure below. Figure 3a As shown in Figure 3b, the energy distribution of the laser spot in the X direction at 3m from the laser 1 exit is shown in Figure 3b.

[0055] from Figures 2a-3b As can be seen, the output spot size of INNO-SLAB slab laser 1 is 3.2 mm, with a flat-top distribution, but a distinct rising edge. According to Kirchhoff's far-field propagation theory of diffraction, as the propagation distance changes, the spot size slowly increases, exhibiting a near-flat-top distribution, and the rising edge of the spot increases.

[0056] This can also be understood as: Laser 1 directly outputs a flat-top light spot, which has processing advantages, but is not directly equivalent to the optimal light spot shape required for focusing in processes such as laser scribing.

[0057] Specifically, regarding the laser spot at the 0m exit of laser 1: the spot has a flat top distribution, meaning that the energy distribution of the beam is relatively uniform, without obvious energy concentration or dispersion. However, the spot at the laser 1 exit has a distinct rising edge, indicating that the energy distribution of the beam is not completely uniform, but rather has a certain transition region. The presence of the rising edge will affect the accuracy and effect of laser scribing and other processing methods.

[0058] For the laser spot at 3m from laser exit point 1: During far-field transmission, a flat-topped laser spot is more likely to maintain its shape stability, retaining a near-flat-top distribution. However, as the transmission distance increases, the uniformity of the laser spot is affected, leading to some deformation in its shape. Furthermore, the rising edge of the laser spot may also increase with the transmission distance. An increased rising edge can affect the accuracy and effectiveness of laser scribing and other processing methods.

[0059] Based on the above analysis of the characteristics of the flat-top beam directly output by laser 1, a beam shaping section 2 is also introduced in the embodiments of this application. The main function of this component is to shape and optimize the flat-top beam directly emitted by laser 1 (specifically, to trim the flat-top beam). The beam shaping section 2 includes a closed opening 20, which is used to trim the flat-top beam emitted by laser 1, so that the edge of the flat-top beam emitted from the closed opening 20 is sharper than the original output beam of laser 1, effectively reducing the transition area of ​​the beam.

[0060] A light spot is an optical phenomenon that occurs when light passes through certain materials or devices. Its shape, size, and brightness distribution are influenced by various factors. When describing a light spot, the term "sharp" is often used to describe its clear edges and distinct boundaries. This description is common in optics, photography, and laser technology. In other words, a flat-topped light spot, cut through a closed opening 20mm, has smoother edges and a clearer edge contour.

[0061] Reference Figure 4a and Figure 4b The beam spot emitted through beam shaping section 2 is very sharp and has no rising edge. The overall morphology of the flat-top beam spot emitted by beam shaping section 2 is as follows: Figure 4a As shown, the overall morphology and X-direction energy distribution of the flat-top beam emitted from beam shaping section 2 are as follows. Figure 4b As shown.

[0062] Specifically, after the flat-top beam directly output by laser 1 is adjusted by the closed opening 20 of beam shaping section 2, the overall shape of the beam is significantly improved: the original rising edge is effectively eliminated, making the energy distribution of the flat-top beam more uniform. This not only improves the quality of the beam but also lays the foundation for subsequent processing operations such as laser scribing.

[0063] For example, the closed opening 20 in the beam shaping section 2 is designed to be smaller than the original flat-top beam spot emitted by the laser 1. When the flat-top beam spot directly output by the laser 1 passes through this smaller closed opening 20, the edge portion of the beam spot (especially those relatively blurred edge areas with rising edges) is trimmed. This process essentially trims the edge of the beam spot, making the edge of the flat-top beam spot that finally exits from the closed opening 20 clearer and sharper. In other words, such a beam spot edge no longer possesses the rising edge characteristics that were originally present, but instead exhibits a more defined and distinct shape. This shaping process greatly improves the clarity of the beam spot and the accuracy of edge definition, which is more conducive to subsequent laser scribing. Specifically, after the processed flat-top beam spot is focused, the focused beam spot acts on the workpiece, resulting in a groove with good sharpness on both sides, without heat-affected zones or crater defects.

[0064] For example, the closed opening 20 has a surface for trimming the flat-top light spot. The surface has a smaller flatness and roughness design, which is beneficial for trimming the edge of the original light spot emitted by the laser 1, so that the edge of the trimmed flat-top light spot is flatter, clearer and sharper.

[0065] For example, the closed opening 20 may also be provided with an auxiliary component, which serves to cut the flat-top light spot. This auxiliary component includes, but is not limited to, a metal blade. For instance, the auxiliary component could also be an optical lens; special optical lenses, such as cylindrical lenses or prisms, can reshape the flat-top light spot, thereby cutting it into the desired shape and flatness. Alternatively, the auxiliary component could be a microlens array, composed of many tiny lenses, each capable of focusing or diffusing the flat-top light spot, thus achieving the cutting of the light spot. Or, the auxiliary component could also be a spatial light modulator, a laser cutting head, etc.

[0066] After the original beam spot emitted from laser 1 is cut by the closed opening 20 of beam shaping section 2, the flat-top beam spot without a rising edge (with a clearer edge) emitted from the closed opening 20 is focused by optical component 3 and applied to the workpiece. For example, the flat-top beam spot emitted from the closed opening 20 is focused by optical component 3 to form a focused beam spot, which applies to the workpiece to perform laser scribing or other operations. The workpiece to be processed includes, but is not limited to, thin-film solar cells and ordinary solar cells. The workpiece to be processed can be any workpiece that requires laser processing (laser scribing or laser cutting).

[0067] Since the light emitted from the closed opening 20 is a flat-topped light spot without an upward edge (with clearer edges), the imaging focusing principle is used to reduce the size of the flat-topped light spot without an upward edge (with clearer edges) and focus it on the processing surface of the workpiece. This effectively reduces the crater defects and heat-affected zone problems that are common in laser scribing and other processes, thereby improving the processing quality.

[0068] In other words, the laser 1 and the beam shaping unit 2 provide a flat-topped spot with clear edges and no rising edge. This flat-topped spot effectively reduces the crater defects and heat-affected zone problems commonly encountered in laser scribing and other processes by providing a uniform energy distribution, reducing thermal stress (the thermal stress generated on the processing material is also relatively uniform during processing), and improving processing accuracy (the flat-topped spot with clear edges can form a more accurate processing contour when focused, which helps to reduce processing errors caused by blurred spot edges).

[0069] Based on the above analysis, the embodiments of this application further include an optical component 3 for focusing the light spot. The laser processing apparatus includes at least one set of optical components 3, the number of which is related to the number of laser processing paths required in the laser processing process. When single-path laser processing is achieved, the laser processing apparatus includes one set of optical components 3. When N-path laser processing is required, the laser processing apparatus includes N sets of optical components 3. For example, referring to… Figure 1 The laser processing device includes 6 laser processing channels, and components can be added or removed to achieve 1-24 laser processing channels as needed.

[0070] Therefore, in this embodiment, the laser processing apparatus includes a laser 1 for directly emitting a flat-top beam, a beam shaping unit 2 for shaping the edge of the flat-top beam, and an optical component 3 for focusing the shaped flat-top beam. The laser processing apparatus provided in this embodiment can reduce crater and heat-affected zone defects, and improve processing results. Furthermore, the laser processing apparatus provided in this embodiment avoids the use of beam expanders and DOEs for beam shaping, thus reducing costs.

[0071] In an embodiment of this application, a metal sheet is provided on the edge of the closed opening 20, and the metal sheet is formed with a blade, the blade facing the interior of the closed opening 20.

[0072] In this embodiment, a metal sheet with a blade is provided at the edge of the closed opening 20, and the blade is positioned facing inwards towards the closed opening 20. Alternatively, the closed opening 20 can be understood as follows: a metal sheet is provided at the edge of the closed opening 20, and a blade is formed on the side of the metal sheet opposite to its provided edge.

[0073] In a preferred embodiment, each side of the closed opening 20 is provided with a metal sheet. When the closed opening 20 has oppositely arranged sides, metal sheets are provided on the sides, and the blades of the metal sheets provided on the oppositely arranged sides are also opposite to each other.

[0074] In this embodiment, a metal sheet is provided on the edge of the closed opening 20. The blade of the metal sheet has a sharp edge, which is used to cut the edge part of the light spot (with rising edge and blurred part), so that the overall shape of the light spot passing through the closed opening 20 is sharp, without rising edge, and the overall energy distribution of the light spot is uniform, which is beneficial for laser scribing and other operations.

[0075] In a further embodiment of this application, the beam shaping part 2 further includes an adjustment mechanism 25, which is used to adjust the opening size of the closed opening part 20.

[0076] In this embodiment, the beam shaping section 2 further includes an adjustment mechanism 25, which is used to adjust the opening size of the closed opening section 20 to accommodate flat-top beams of different shapes and sizes emitted from the laser 1, and to meet the requirements of focused beams of different shapes and sizes.

[0077] For example, taking a square shape as an example, the size of the closed opening 20 can be adjusted by adjusting the length and width of the closed opening 20 through the adjusting mechanism 25.

[0078] In one specific embodiment, refer to Figure 5 The closed opening 20 includes four movable parts: a first movable part 21, a second movable part 22, a third movable part 23, and a fourth movable part 24. These four movable parts are joined together to form the closed opening 20, which has a square opening shape.

[0079] An adjustment knob (adjustment mechanism 25) is provided on one side of the second movable part 22 and the fourth movable part 24. By rotating the adjustment knob, the size of the closed opening 20 in the width direction can be adjusted. An adjustment rotation (adjustment mechanism 25) is provided on the other side of the third movable part 23 and the fourth movable part 24. By rotating the adjustment rotation, the size of the closed opening 20 in the length direction can be adjusted. In other words, in this specific embodiment, by rotating the adjustment rotations on both sides of the closed opening 20, the size of the opening in the length and width directions of the closed opening 20 can be changed to accommodate different sizes of flat-topped square light spots emitted by the laser 1, and to meet the requirements of different shapes and sizes of focused light spots.

[0080] In the embodiments of this application, reference is made to Figure 1 Along the transmission direction of the emitted light spot of the laser 1, the optical component 3 includes a phase delay plate 31 and a beam splitter 32 arranged in sequence, and the optical component 3 also includes a focusing lens group 33 located in the reflection light path of the beam splitter 32.

[0081] The phase delay film 31 is used to change the polarization direction of linearly polarized light; the beam splitter 32 is used to split a beam of light into two beams, and the beam splitter 32 is used to reflect one of the two beams of light and transmit the other of the two beams of light; the focusing lens group 33 is used to receive the light reflected by the beam splitter 32 and focus the light onto the workpiece.

[0082] In this embodiment, the phase delay plate 31 is used to change the polarization direction of linearly polarized light. For example, the flat-top light spot emitted by laser 1 is linearly polarized light, which can be S-light, P-light, or linearly polarized light with any polarization direction. Alternatively, laser 1 can emit circularly polarized light, in which case a quarter-wave plate needs to be placed in the transmission direction of the light spot emitted by laser 1 to modulate the circularly polarized light into linearly polarized light.

[0083] Taking the emitted light from laser 1 as an example of S-beam: the phase retardation plate 31 can change the S-beam into a mixed polarization state of S-beam and P-beam. For example, by rotating the phase retardation plate 31, light with a single polarization component can be changed into a mixed polarization state containing multiple polarization components. In this way, after the light is split by the beam splitting element 32, single-channel laser processing or multi-channel laser processing can be realized.

[0084] For example, when single-path laser processing is required, the light transmitted by the beam splitter 32 is absorbed or eliminated, and the light reflected by the beam splitter 32 is focused by the focusing lens group 33 to form a focused spot for processing the workpiece.

[0085] For example, when multi-channel laser processing is required, the light reflected by the beam splitter 32 is focused by the focusing lens group 33 to form a focused spot for processing the workpiece. The light transmitted by the beam splitter 32 is received by the phase retarder 31 in the adjacent optical assembly 3 and adjusted into mixed polarized light of S-ray and P-ray.

[0086] For example, the beam splitter 32 can be a flat polarizing beam splitter or a polarizing beam splitter prism.

[0087] For example, the number of focusing lenses in the focusing lens group 33 can be one, two, or more. In this embodiment, the number of focusing lenses in the focusing lens group 33 is not limited, as long as the light spot can be focused to achieve laser processing.

[0088] In one specific embodiment, the phase delay plate 31 is a half-wave plate, which is configured to be rotatable.

[0089] In this embodiment, the example is taken where the light received by the half-wave plate is S-beam, and the emitted light is a mixed polarization state of S-beam and P-beam:

[0090] When S-beams pass through a half-wave plate, their polarization direction rotates. The rotation angle is twice the angle between the vibration direction of the incident linearly polarized light and the fast axis of the half-wave plate. Therefore, to obtain mixed S- and P-polarized light, the half-wave plate needs to be rotated to a specific angle so that the polarization direction of the outgoing light is neither in the plane of incidence (not purely P-beam) nor completely perpendicular to the plane of incidence (not purely S-beam).

[0091] Specifically, this particular angle refers to the angle between the vibration direction of the S-polarized light and the fast axis of the half-wave plate; it is neither 0° (parallel) nor 90° (perpendicular). When this angle exists, the polarization direction of the S-polarized light will rotate by an angle after passing through the half-wave plate. Since the rotated polarization direction is neither in the plane of incidence (not purely P-polarized light) nor completely perpendicular to the plane of incidence (not purely S-polarized light), the outgoing light becomes a mixed polarized light of S and P.

[0092] Furthermore, the specific value of this particular angle depends on the ratio of S-rays to P-rays in the desired mixed polarized light. By adjusting the rotation angle of the half-wave plate, the relative intensity of S-rays and P-rays in the output light can be changed, thereby obtaining the desired mixed polarized light.

[0093] In other words, in this embodiment, a linearly polarized light with a single polarization component is changed into a mixed polarized light containing multiple polarization components by rotating a half-wave plate. The energy ratio of the linearly polarized light with different polarization components is related to the rotation angle of the half-wave plate.

[0094] When performing multi-channel laser processing, multiple optical components 3 are sequentially set along the transmission direction of the laser beam emitted from the laser 1. The beam is split and transmitted through the beam splitting element 32, and the energy of each beam is monitored in real time through the feedback control system, which can ensure the consistency of the energy of each beam.

[0095] In an embodiment of this application, a beam-splitting film is disposed on the surface of the beam-splitting element 32 near the phase delay film 31.

[0096] In this embodiment, a beam-splitting film is disposed on the surface of the beam-splitting element 32 near the phase retardation film 31. The beam-splitting film has the ability to selectively reflect or transmit light with a specific polarization direction. For example, the beam-splitting film can separate S-beams and P-beams; for instance, the beam-splitting film can reflect S-beams and transmit P-beams, or it can reflect P-beams and transmit S-beams.

[0097] For example, a beam-splitting film is deposited on the surface of the beam-splitting element 32 near the phase retardation film 31.

[0098] For example, the beam splitter can be a polarizing beam splitter.

[0099] In an embodiment of this application, the surface of the beam splitter 32 facing away from the phase retardation film 31 is provided with an anti-reflection film.

[0100] In this embodiment, an anti-reflection film is provided on the surface of the beam splitter 32 away from the phase retarder 31. The anti-reflection film can significantly reduce the reflection of light on the surface, so that more light can pass through the beam splitter 32 and enter the subsequent optical components 3.

[0101] In the embodiments of this application, reference is made to Figure 1The laser processing device includes at least two sets of optical components 3, which are arranged sequentially along the transmission direction of the laser beam emitted from the laser 1. In two adjacent sets of optical components 3, the phase delay plate 31 in the downstream optical component 3 is used to receive the light transmitted by the beam splitter 32 in the upstream optical component 3.

[0102] In this embodiment, the laser processing device includes at least two sets of optical components 3, and the laser processing device can realize at least two laser processing, such as laser scribing.

[0103] At least two sets of optical components 3 are arranged sequentially along the transmission direction of the laser beam emitted from the laser 1, so as to facilitate at least two laser processing on the same workpiece.

[0104] In the case where the laser processing apparatus includes at least two sets of optical components 3, in adjacent optical components 3, the downstream optical component 3 is used to receive the light transmitted by the beam splitter 32 of the upstream optical component 3. Furthermore, the downstream optical component 3 passes the received light through a phase retardation plate 31 to change the polarization direction of the received light for subsequent laser processing.

[0105] Therefore, in this embodiment, without affecting the uniformity of the energy distribution of the flat-top spot, the laser processing device can realize multi-channel laser processing, and in any one of the laser processing channels, by focusing a flat-top spot with uniform energy distribution, the crater and heat-affected zone defects are reduced, and the processing effect is improved.

[0106] In a further embodiment of this application, the laser processing apparatus further includes a collimating element 4, which is located between the beam shaping section 2 and the optical component 3.

[0107] In this embodiment, the laser processing apparatus can perform single-channel laser processing and multi-channel laser processing. When the laser processing apparatus performs single-channel laser processing, the collimating element 4 is not required. When the laser processing apparatus performs multi-channel laser processing, the collimating element 4 needs to be provided between the beam shaping section 2 and the optical component 3 (the optical component 3 is the one closest to the beam shaping section 2 when multiple sets of optical components 3 are provided).

[0108] Specifically, in laser processing equipment, when multiple laser beams need to be processed simultaneously, a common problem is that the object distance between the beam shaping unit 2 and each focusing lens group 33 differs, resulting in different working distances for each processing path, which complicates system debugging. To effectively solve this problem, this embodiment introduces a collimating element 4. The collimating element 4 converts the laser beam into a near-parallel light state. In this way, even if the object distances of each path are different, under the adjustment of the collimating element 4, the laser beams can maintain relatively consistent optical characteristics when they reach the focusing lens group 33, thereby ensuring the consistency and stability of laser processing and simplifying the system debugging process.

[0109] In one specific embodiment, the collimating element 4 can be a relay lens group or a beam-expanding collimating lens group. For example, the collimating element 4 may include one, two, or more relay lenses. Alternatively, the collimating element 4 may include one, two, or more beam-expanding collimating lenses.

[0110] For example, the relay lens can be a plano-convex lens on a quartz substrate.

[0111] In a further embodiment of this application, the laser processing apparatus further includes a mirror assembly located between the beam shaping section 2 and the collimating element 4.

[0112] In this embodiment, when the optical path length between the collimating element 4 and the beam shaping section 2 is long, a mirror group is provided between the beam shaping section 2 and the collimating element 4 to shorten the optical path length.

[0113] In one specific embodiment, according to as follows Figure 1 A laser processing device is constructed. This device can perform six-channel laser processing. The collimating element 4 includes a relay mirror, and the focusing lens group 33 includes a focusing mirror.

[0114] The laser output spot size of laser 1 is 3.2mm*3.2mm, the spot size at beam shaping section 2 is 3mm*3mm, the repeater lens focal length is f3000mm, and the distance between the repeater lens and beam shaping section 2 is 3000mm. The laser processing device includes 6 sets of optical components 3, each of which includes a half-wave plate, a beam splitter 32, and a focusing lens. The distance from the focusing lens to the working surface (the processing surface of the workpiece) is 100mm. By moving the spacing between the optical components 3, different line spacing processing requirements for the 1st to 6th paths can be achieved.

[0115] The focused spot effect diagrams and energy distribution diagrams of channels 1 and 6 were obtained using the optical simulation software Zemax, as shown below. Figures 6a-7b As shown.

[0116] The distribution diagram of the focused beam spot for the first path is as follows: Figure 6a As shown, the energy distribution diagram of the first focused spot in the X direction is as follows: Figure 6b As shown.

[0117] The distribution diagram of the focused spot on the 6th channel is as follows: Figure 7a As shown, the energy distribution diagram of the 6th focused spot in the X direction is as follows. Figure 7b As shown.

[0118] from Figures 6a-7b As can be seen, the focusing spot size of both the first and sixth channels is 100um*100um, and the spot uniformity is ≥96%, which meets the processing requirements. The formula for spot uniformity is: Uniformity = 1 - (maximum illuminance - minimum illuminance) / (maximum illuminance + minimum illuminance) * 100%.

[0119] And using the optical simulation software Zemax, the effect image and energy distribution diagram of the first focused spot defocused by ±0.2mm were obtained, as shown below. Figures 8a-9b As shown.

[0120] The effect of the first-path light focusing spot defocusing by +0.2mm is shown in the image below. Figure 8a As shown, the energy distribution pattern of the light spot in the X direction is as follows: Figure 8b As shown, the focused spot is defocused by +0.2mm, and the spot size is 105um*105um.

[0121] The effect of the first light focusing spot being defocused by 0.2mm is shown in the image below. Figure 9a As shown, the energy distribution pattern of the light spot in the X direction is as follows: Figure 9b As shown, the focused spot is defocused by 0.2mm, and the spot size is 95um*95um.

[0122] from Figures 8a-9b As can be seen, with a defocus of ±0.2mm, the spot size still meets the process range of ±5µm linewidth variation. The system using DOE shaping has a depth-of-focus range of only ±0.1mm. In other words, in this embodiment, in addition to achieving multi-path optical shaping, long focal depth processing can also be guaranteed.

[0123] This application also provides a solar cell processing system. The solar cell processing system includes the laser processing apparatus as described above.

[0124] This application also provides a solar cell processing system, which includes a laser processing device. When processing solar cells using this solar cell processing system, the processing effect can be improved and the processing quality can be ensured.

[0125] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0126] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A laser processing apparatus, characterized in that, include: Laser (1) is used to emit a flat-top beam; A beam shaping section (2) is located on the light-emitting side of the laser (1). The beam shaping section (2) includes a closed opening section (20), which includes four movable parts. The four movable parts are spliced ​​together to form the closed opening section (20). The opening shape of the closed opening section (20) is square. The closed opening section (20) is used to cut the flat-top light spot emitted by the laser (1). A metal sheet is provided on the edge of the closed opening section (20). The metal sheet is formed with a blade, and the blade faces the inside of the closed opening section (20). At least one optical component (3) is located on the light-emitting side of the beam shaping part (2). The optical component (3) is used to form a focused light spot, which acts on the workpiece to be processed.

2. The laser processing apparatus according to claim 1, characterized in that, The beam shaping section (2) further includes an adjustment mechanism (25) for adjusting the opening size of the closed opening section (20).

3. The laser processing apparatus according to claim 1, characterized in that, Along the transmission direction of the emitted light spot of the laser (1), the optical assembly (3) includes a phase delay plate (31) and a beam splitter (32) arranged in sequence, and the optical assembly (3) also includes a focusing lens group (33) located in the reflection light path of the beam splitter (32). The phase delay plate (31) is used to change the polarization direction of linearly polarized light; The beam splitter (32) is used to split a beam of light into two beams, and the beam splitter (32) is used to reflect one of the two beams of light and transmit the other of the two beams of light. The focusing lens group (33) is used to receive the light reflected by the beam splitter (32) and focus the light onto the workpiece.

4. The laser processing apparatus according to claim 3, characterized in that, The phase delay plate (31) is a half-wave plate, which is configured to be rotatable.

5. The laser processing apparatus according to claim 3, characterized in that, The beam splitter (32) has a beam splitting film disposed on the surface near the phase delay film (31).

6. The laser processing apparatus according to claim 3 or 5, characterized in that, The surface of the beam splitter (32) facing away from the phase delay film (31) is provided with an anti-reflection film.

7. The laser processing apparatus according to claim 1 or 3, characterized in that, The laser processing device includes at least two sets of optical components (3), and the at least two sets of optical components (3) are arranged sequentially along the transmission direction of the emitted light spot of the laser (1); in the two adjacent sets of optical components (3), the phase delay plate (31) in the downstream optical component (3) is used to receive the light transmitted by the beam splitter (32) in the upstream optical component (3).

8. The laser processing apparatus according to claim 7, characterized in that, The laser processing apparatus further includes a collimation element (4), which is located between the beam shaping section (2) and the optical component (3).

9. The laser processing apparatus according to claim 8, characterized in that, The collimating element (4) is a relay lens group.

10. The laser processing apparatus according to claim 8 or 9, characterized in that, The laser processing apparatus further includes a mirror assembly located between the beam shaping section (2) and the collimating element (4).

11. A solar cell processing system, characterized in that, The solar cell processing system includes a laser processing device as described in any one of claims 1-10.

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