Perovskite laser scribing equipment

Abstract

The perovskite laser scribing equipment comprises a machine base (1), a Y-axis driving part (2) and a mounting frame (3) are arranged on the machine base (1), and a workbench (4) is arranged at the moving end of the Y-axis driving part (2); an X-axis driving part (5) is arranged on the mounting frame (3), a Z-axis driving part (6) is arranged at the moving end of the X-axis driving part (5), an infrared laser scribing module (7) and a green laser scribing module (8) are arranged at the moving end of the Z-axis driving part (6), and the infrared laser scribing module (7) is used for emitting infrared laser to scribe a workpiece on the workbench (4); double-light-path machining is conducted through the infrared laser scribing module and the green laser scribing module, the machining efficiency is improved, meanwhile, the light path positioning mechanism drives the collecting camera to move so that the collecting camera can accurately correspond to scribing points, and the machining accuracy is ensured.

Description

Technical Field

[0001] The present invention relates to the field of laser processing, and particularly to a perovskite laser scribing device. Background Art

[0002] A perovskite solar cell is a solar cell that uses a perovskite-type organometallic halide semiconductor as a light-absorbing material. It consists of a perovskite light-absorbing layer in the middle, electron and hole transport layers on both sides of the light-absorbing layer, and an electrode layer on the outermost layer. During processing, laser processing needs to be performed on each layer to form an electrical connection structure, including a total of four laser processes, namely P1 - P4, which act on the electrode layer, perovskite light-absorbing layer, electron transport layer, and hole transport layer respectively. Finally, edge shaping (i.e., edge cleaning) is carried out. The laser sources used in different processes are also different. Therefore, at present, it is necessary to transfer between different laser processing devices to complete the complete processing process, and the operation is cumbersome. Summary of the Invention

[0003] The purpose of the present invention is to provide a perovskite laser scribing device. The present invention performs dual-path processing through an infrared laser scribing module and a green laser scribing module to improve processing efficiency. At the same time, an optical path positioning mechanism drives a collection camera to move, so that it accurately corresponds to the scribing point, ensuring the accuracy of processing.

[0004] The technical solution provided by the present invention is as follows: A perovskite laser scribing device includes a machine base. A Y-axis driving member and a mounting frame are provided on the machine base. A workbench is provided on the moving end of the Y-axis driving member; an X-axis driving member is provided on the mounting frame, and a Z-axis driving member is provided on the moving end of the X-axis driving member. An infrared laser scribing module and a green laser scribing module are provided on the moving end of the Z-axis driving member. The infrared laser scribing module is used to emit infrared laser to scribe and process the workpiece on the workbench, and the green laser scribing module is used to emit green laser to scribe and process the components on the workbench; an optical path positioning mechanism is provided on the moving end of the Z-axis driving member, and a collection camera is provided at the output end of the optical path positioning mechanism. The optical path positioning mechanism drives the collection camera to move, so that the receiving end of the collection camera corresponds to the infrared laser scribing point of the infrared laser scribing module or the green laser scribing point of the green laser scribing module.

[0005] In the above perovskite laser scribing device, the workbench includes a rectangular fixed seat. A right-angle support frame is fixed on one side of the fixed seat. An adjustable straight edge with quick-release connection is provided on the fixed seat. The top surfaces of the adjustable straight edge and the right-angle support frame jointly form a workpiece support surface; Rotating connection pressing members are provided on both the right-angle support frame and the adjustable straight edge, and there is a gap between the pressing members and the workpiece support surface.

[0006] In the aforementioned perovskite laser scribing device, a dust suction groove is provided on the top surface of the fixed seat, and a dust suction port communicating with the dust suction groove is provided on the side surface of the fixed seat.

[0007] In the aforementioned perovskite laser scribing equipment, the infrared laser scribing module includes a first mirror base and a galvanometer base disposed on the mobile end of the Z-axis driving member. An infrared laser head is provided at the incident end of the first mirror base. The outgoing end of the first mirror base is connected to the incident end of the galvanometer base, and the outgoing end of the galvanometer base faces vertically downward.

[0008] In the aforementioned perovskite laser scribing equipment, the green laser scribing module includes a green laser disposed on the machine base. A second mirror base is provided at the emitting end of the green laser. A third mirror base connected to the second mirror base is provided on the mounting bracket. A fourth mirror base is provided on the mobile end of the X-axis driving member, and the incident end of the fourth mirror base corresponds to the outgoing end of the third mirror base. A fifth mirror base and a focusing cutting head are provided on the mobile end of the Z-axis driving member. The incident end of the fifth mirror base corresponds to the outgoing end of the fourth mirror base. The outgoing end of the fifth mirror base is connected to the focusing cutting head, and the outgoing end of the focusing cutting head faces vertically downward.

[0009] In the aforementioned perovskite laser scribing equipment, a dust collection hood enclosing the emitting ends of the infrared laser scribing module and the green laser scribing module is provided on the mobile end of the X-axis driving member.

[0010] In the aforementioned perovskite laser scribing equipment, the optical path positioning mechanism includes a rotating disk disposed on the mobile end of the Z-axis driving member and connected to the driving component. A lateral adjustment block is provided on the side of the front surface of the rotating disk. A longitudinal adjustment block is provided on the line connecting the lateral adjustment block and the center of the rotating disk. A lateral adjustment plate is provided on the front side of the rotating disk and is elastically and movably connected to the mobile end of the Z-axis driving member horizontally. A lateral positioning port for accommodating the lateral adjustment block and the longitudinal adjustment block is provided on the lateral adjustment plate. Symmetric arc-shaped positioning surfaces are provided on both sides of the lateral positioning port. The radius of the arc-shaped positioning surface is equal to the distance from the lateral adjustment block to the center of the rotating disk, and the center of the arc-shaped positioning surface and the center of the rotating disk are located on the same horizontal line. Horizontal driving ports are provided vertically at both the upper and lower ends of the lateral positioning port and are adapted to the lateral adjustment block. A vertical adjustment plate is vertically movably connected to the front surface of the lateral adjustment plate. A strip-shaped driving groove is provided horizontally on the back surface of the vertical adjustment plate. The longitudinal adjustment block passes through the lateral positioning port and cooperates with the strip-shaped driving groove. The acquisition camera is connected to the vertical adjustment plate.

[0011] In the aforementioned perovskite laser scribing equipment, positioning members are symmetrically provided on the mobile end of the Z-axis driving member. An activity plate movably connected to the corresponding side positioning member is provided on the side of the lateral adjustment plate. A baffle is provided at the end of the activity plate, and a spring is provided between the baffle and the corresponding side positioning member.

[0012] In the aforementioned perovskite laser scribing equipment, the radian of the arc-shaped positioning surface is less than 180°.

[0013] Compared with the prior art, when the present invention is in processing, the workpiece to be processed is placed on the workbench. The X-axis driving member and the Z-axis driving member drive the infrared laser scribing module and the green laser scribing module to move in the X-axis and Z-axis directions, and the Y-axis driving member drives the workbench to move in the Y-axis direction. The cooperation of the three enables the infrared laser scribing module and the green laser scribing module to process any position of each layer of the workpiece, and at the same time has both infrared laser and green laser, meeting the requirements of different processes, so that multiple processes can be processed on a single device, with high efficiency. When switching the processing between the infrared laser scribing module and the green laser scribing module, the optical path positioning mechanism drives the acquisition camera to move, so that its receiving end corresponds to the laser optical path in the working state, avoiding the imaging distortion caused by the edge distortion of the lens and making the optical path capture generate errors, effectively improving the processing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic structural diagram of the present invention;

[0015] Figure 2 is a schematic structural diagram of the back of the present invention;

[0016] Figure 3 is a schematic structural diagram of the workbench of the present invention;

[0017] Figure 4 is a schematic structural diagram of the optical path positioning mechanism of the present invention;

[0018] Figure 5 is a schematic structural diagram of the rotating disk and the transverse adjusting plate of the present invention;

[0019] Figure 6 is a schematic structural diagram of the transverse positioning port of the present invention;

[0020] Figure 7 is a schematic structural diagram of the back of the vertical adjusting plate of the present invention.

[0021] The markings in the attached drawings are as follows: 1, machine base; 2, Y-axis driving member; 3, mounting frame; 4, workbench; 5, X-axis driving member; 6, Z-axis driving member; 7, infrared laser scribing module; 8, green laser scribing module; 9, optical path positioning mechanism; 10, acquisition camera; 11, fixing seat; 12, right-angle support frame; 13, adjusting straight edge; 14, workpiece support surface; 15, pressing member; 16, dust suction groove; 17, dust suction port; 18, first mirror seat; 19, galvanometer seat; 20, infrared laser head; 21, second mirror seat; 22, third mirror seat; 23, fourth mirror seat; 24, fifth mirror seat; 25, focusing cutting head; 26, dust collection cover; 27, rotating disk; 28, transverse adjusting block; 29, longitudinal adjusting block; 30, transverse adjusting plate; 31, transverse positioning port; 32, arc-shaped positioning surface; 33, transverse driving port; 34, strip-shaped driving groove; 35, vertical adjusting plate; 36, positioning member; 37, movable plate; 38, baffle; 39, spring; 40, green laser. Detailed implementation mode

[0022] The present invention will be further described below in conjunction with embodiments and the attached drawings, but it is not used as a basis for limiting the present invention.

[0023] Embodiment: A perovskite laser scribing device, as shown in the attached Figure 1 and the attached Figure 2 figures, includes a machine base 1. A Y-axis driving member 2 and an arched mounting frame 3 are assembled on the machine base 1. A workbench 4 is assembled on the moving end of the Y-axis driving member 2. An X-axis driving member 5 is assembled on the mounting frame 3. A Z-axis driving member 6 is assembled on the moving end of the X-axis driving member 5. An infrared laser scribing module 7 and a green laser scribing module 8 are assembled on the moving end of the Z-axis driving member 6. The infrared laser scribing module 7 is used to emit infrared laser to scribe the workpiece on the workbench 4. The green laser scribing module 8 is used to emit green laser to scribe the components on the workbench 4. The Y-axis driving member, X-axis driving member, and Z-axis driving member adopt a linear motor or a ball screw drive method to achieve linear movement on the guide rail, and the maximum moving speed is 1000 mm / s, which is a technical means well-known and mastered by those skilled in the art and will not be elaborated here. An optical path positioning mechanism 9 is assembled on the moving end of the Z-axis driving member 6. An acquisition camera 10 is assembled on the output end of the optical path positioning mechanism 9. The acquisition camera is a CCD camera with a pixel greater than or equal to 5 million, having high sensitivity, low noise, wide dynamic range, and high color reproduction. The optical path positioning mechanism 9 drives the acquisition camera 10 to move, so that the receiving end of the acquisition camera 10 is opposite to the infrared laser scribing point of the infrared laser scribing module 7 or the green laser scribing point of the green laser scribing module 8. As shown in the attached Figure 3As shown in the figure, the workbench 4 includes a rectangular fixed base 11. One side of the fixed base 11 is fixedly provided with a right-angle support frame 12. An adjustable straight edge 13 is detachably connected to the fixed base 11 by means of holes and bolts. The top surfaces of the adjustable straight edge 13 and the right-angle support frame 12 jointly form a workpiece support surface 14. The adjustable straight edge can move along with the distribution of the holes, thereby adjusting the size of the workpiece support surface. The maximum workpiece support surface is 300 mm × 300 mm, which is suitable for workpieces of various sizes. Rotationally connected pressing members 15 are assembled on both the right-angle support frame 12 and the adjustable straight edge 13. There is a gap between the pressing members 15 and the workpiece support surface 14 for positioning the workpiece, and the bottom surface of the pressing member has friction patterns to improve the reliability of positioning. A dust suction groove 16 is formed on the top surface of the fixed base 11, and a dust suction port 17 communicated with the dust suction groove 16 is integrally formed on the side surface of the fixed base 11. A dust collector is connected to the dust suction port for timely extracting waste materials. The infrared laser scribing module 7 includes a first mirror seat 18 and a galvanometer seat 19 assembled on the moving end of the Z-axis driving member 6. An infrared laser head 20 with a frequency of 1 k - 4000 khz and a pulse width of 2 - 500 ns is fixed to the incident end of the first mirror seat 18 through an optical fiber head seat. The outgoing end of the first mirror seat 18 is connected to the incident end of the galvanometer seat 19 through a sealed tube. The outgoing end of the galvanometer seat 19 is vertically downward, bending the optical path propagation path to improve the space utilization rate. The green laser scribing module 8 includes a green laser 40 with a frequency of 200 k - 800 khz and a pulse width < 15 ps assembled on the machine base 1. The emitting end of the green laser 40 is connected to a second mirror seat 21 through a sealed tube. A third mirror seat 22 connected to the second mirror seat 21 through a sealed tube is assembled on the mounting frame 3. A fourth mirror seat 23 is provided on the moving end of the X-axis driving member 5. The incident end of the fourth mirror seat 23 corresponds to the outgoing end of the third mirror seat 22, and a bellows protective cover (not shown in the figure) for wrapping the optical path is assembled between the two. A fifth mirror seat 24 and a focusing cutting head 25 are assembled on the moving end of the Z-axis driving member 6. The incident end of the fifth mirror seat 24 corresponds to the outgoing end of the fourth mirror seat 23, and a bellows protective cover for wrapping the optical path is assembled between the two. The outgoing end of the fifth mirror seat 24 is connected to the focusing cutting head 25 through a sealed tube, and the outgoing end of the focusing cutting head 25 is vertically downward. A dust collection cover 26 surrounding the emitting ends of the infrared laser scribing module 7 and the green laser scribing module 8 is assembled on the moving end of the X-axis driving member 5. As shown in the appendix Figure 4 - Appendix Figure 7As shown in the figure, the optical path positioning mechanism 9 includes a rotating disk 27 assembled on the moving end of the Z-axis driving member 6 and connected to a micro rotating motor. A transverse adjusting block 28 is integrally formed on the front side of the rotating disk 27. A longitudinal adjusting block 29 is integrally formed on the line connecting the transverse adjusting block 28 and the center of the rotating disk 27. A transverse adjusting plate 30 elastically and movably connected to the moving end of the Z-axis driving member 6 horizontally is assembled on the front side of the rotating disk 27. A transverse positioning port 31 for accommodating the transverse adjusting block 28 and the longitudinal adjusting block 29 is formed on the transverse adjusting plate 30. Symmetric 90° outward convex arc-shaped positioning surfaces 32 are provided on both sides of the transverse positioning port 31. The radius of the arc-shaped positioning surface 32 is equal to the distance from the transverse adjusting block 28 to the center of the rotating disk 27, and the center of the arc-shaped positioning surface 32 and the center of the rotating disk 27 are located on the same horizontal line. Transverse driving ports 33 arranged vertically are formed at both the upper and lower ends of the transverse positioning port 31, and the transverse driving ports 33 are adapted to the transverse adjusting block 28. A vertically adjusting plate 35 movably connected vertically is assembled on the front side of the transverse adjusting plate 30. A horizontally arranged strip-shaped driving groove 34 is formed on the back of the vertically adjusting plate 35. The longitudinal adjusting block 29 passes through the transverse positioning port 31 and cooperates with the strip-shaped driving groove 34. The acquisition camera 10 is connected to the vertically adjusting plate 35. When the transverse adjusting block fits with the arc-shaped positioning surface, due to the corresponding relationship of the radii of the arc-shaped positioning surfaces, the transverse adjusting block will not drive the transverse adjusting plate to move at any position on the arc-shaped positioning surface. Further, with the elasticity of the transverse adjusting plate, it is fixed at the current position. At this time, when the turntable rotates, the longitudinal adjusting block will push the strip-shaped driving groove and then drive the vertically adjusting plate to move up and down, thereby adjusting the focal position of the acquisition camera. When the transverse adjusting block leaves the arc-shaped positioning surface and enters the transverse driving port, the transverse adjusting block will drive the transverse adjusting plate to move horizontally by pushing the straight surface on the side of the transverse driving port until the transverse adjusting block leaves the transverse driving port again and enters the transverse positioning port to fit with the arc-shaped positioning surface on the other side, realizing the horizontal movement of the acquisition camera. By adjusting the distance between the transverse adjusting block and the center of the rotating disk and the radian and radius of the arc-shaped positioning surface, the horizontal movement distance of the transverse adjusting plate can be accurately controlled, so as to correspond to the horizontal spacing of the emission ends of the infrared laser scribing module and the green laser scribing module. When the laser is switched for processing, the rotation of the rotating disk can drive the acquisition camera to face the processed laser optical path for acquisition, and at the same time, its focus can be flexibly controlled, so as to accurately capture and improve the processing accuracy. Symmetrically arranged C-shaped positioning members 36 are assembled on the moving end of the Z-axis driving member 6. A movable plate 37 fitted with the corresponding side positioning member 36 is integrally formed on the side of the transverse adjusting plate 30. A baffle 38 is integrally formed at the end of the movable plate 37. A spring 39 is provided between the baffle 38 and the corresponding side positioning member 36. When moving, the spring is compressed and stretched to provide elastic force.The base is integrated with a controller electrically connected to each component, which receives signals and adjusts the laser frequency power, the direction speed of the drive, the speed of the galvanometer seat, the camera mark / line capture, etc. These are technical means well known and mastered by those skilled in the art, and will not be described in detail here. ;

[0024] Working principle: The workpiece is placed on the workpiece support surface 14 of the workbench 4. The size of the support surface can be flexibly adjusted by adjusting the straight edge 13 to adapt to workpieces of various sizes. The press piece 15 rotatably connected to the right-angle support frame 12 and the adjustable straight edge 13 is used to position the workpiece by utilizing the gap between it and the workpiece support surface 14. The friction texture on the bottom surface of the press piece increases the stability of positioning and prevents the workpiece from being displaced during the processing process.

[0025] The X-axis drive 5, Z-axis drive 6 and Y-axis drive 2 of the equipment work together. The X-axis drive 5 and Z-axis drive 6 drive the infrared laser scribing module 7 and the green laser scribing module 8 to move in the X-axis and Z-axis directions, and the Y-axis drive 2 drives the workbench 4 to move in the Y-axis direction. This enables the infrared laser scribing module 7 and the green laser scribing module 8 to process any position of each layer of the workpiece. The infrared laser head 20 in the infrared laser scribing module 7 emits infrared laser, and the workpiece is scribed after the optical path is adjusted by the first reflector seat 18 and the galvanometer seat 19; the green laser 40 in the green laser scribing module 8 emits green laser, which is transmitted and focused by multiple reflector seats and the focusing cutting head 25 to achieve scribing of the workpiece; the two lasers have different parameters such as frequency and pulse width, which meet the processing requirements of different process layers of perovskite solar cells, complete multiple processes on a single device, and improve processing efficiency.

[0026] When it is necessary to switch processing between the infrared laser scribing module 7 and the green laser scribing module 8, the rotating disk 27 in the optical path positioning mechanism 9 rotates under the drive of the micro-rotating motor, driving the lateral adjustment block 28 and the longitudinal adjustment block 29 to move. The lateral adjustment block 28 cooperates with the arc positioning surface 32 and the lateral driving port 33 of the lateral positioning port 31, and the longitudinal adjustment block 29 cooperates with the strip driving groove 34 on the back of the vertical adjustment plate 35 to realize the lateral and vertical movement of the acquisition camera 10. In this way, the receiving end of the acquisition camera 10 can accurately correspond to the laser optical path of the current working state, avoiding imaging deformation due to lens edge distortion, thereby generating optical path capture errors, and effectively improving processing accuracy.

Claims

1. A perovskite laser scribing device, characterized in that: The machine base (1) comprises a Y-axis driving member (2) and a mounting frame (3) provided on the machine base (1); a movable end of the Y-axis driving member (2) is provided with a workbench (4); an X-axis driving member (5) is provided on the mounting frame (3); a Z-axis driving member (6) is provided on the movable end of the X-axis driving member (5); an infrared laser scribing module (7) and a green laser scribing module (8) are provided on the movable end of the Z-axis driving member (6); the infrared laser scribing module (7) is used to emit an infrared laser to scribing a workpiece on the workbench (4) Processing, the green laser scribing module (8) is used to emit green laser to perform scribing processing on the components on the workbench (4); the moving end of the Z-axis driving member (6) is provided with an optical path positioning mechanism (9), the output end of the optical path positioning mechanism (9) is provided with a collection camera (10), and the optical path positioning mechanism (9) drives the collection camera (10) to move, so that the receiving end of the collection camera (10) corresponds to the infrared laser scribing point of the infrared laser scribing module (7) or the green laser scribing point of the green laser scribing module (8).

2. The perovskite laser scribing device according to claim 1, characterized in that: The workbench (4) comprises a rectangular fixed seat (11), a right-angle support frame (12) is fixed on one side of the fixed seat (11), an adjustment straight edge (13) with a quick-release connection is provided on the fixed seat (11), and the top surface of the adjustment straight edge (13) and the right-angle support frame (12) are connected together to form a workpiece support surface (14); the right-angle support frame (12) and the adjustment straight edge (13) are both provided with a rotatably connected pressing piece (15), and a gap is provided between the pressing piece (15) and the workpiece support surface (14).

3. The perovskite laser scribing device according to claim 2, characterized in that: The top surface of the fixing seat (11) is provided with a dust suction groove (16), and the side surface of the fixing seat (11) is provided with a dust suction port (17) which is in communication with the dust suction groove (16).

4. The perovskite laser scribing device according to claim 1, characterized in that: The infrared laser scribing module (7) comprises a first reflector seat (18) and a galvanometer seat (19) arranged at the moving end of the Z-axis driving member (6); an infrared laser head (20) is arranged at the incident end of the first reflector seat (18); an output end of the first reflector seat (18) is connected to the incident end of the galvanometer seat (19); and an output end of the galvanometer seat (19) faces vertically downward.

5. The perovskite laser scribing device according to claim 1, characterized in that: The green laser scribing module (8) comprises a green laser (40) arranged on a machine base (1), the emission end of the green laser (40) being provided with a second reflector seat (21), and the mounting frame (3) being provided with a third reflector seat (22) connected to the second reflector seat (21); a fourth reflector seat (23) being provided on the movable end of the X-axis driving member (5), the incident end of the fourth reflector seat (23) corresponding to the emission end of the third reflector seat (22); a fifth reflector seat (24) and a focusing cutting head (25) being provided on the movable end of the Z-axis driving member (6), the incident end of the fifth reflector seat (24) corresponding to the emission end of the fourth reflector seat (23), the emission end of the fifth reflector seat (24) being connected to the focusing cutting head (25), and the emission end of the focusing cutting head (25) facing vertically downward.

6. The perovskite laser scribing device according to claim 1, characterized in that: A dust collecting cover (26) is provided on the movable end of the X-axis driving member (5) and surrounds the emitting end of the infrared laser scribing module (7) and the emitting end of the green laser scribing module (8).

7. The perovskite laser scribing device according to claim 1, characterized in that: The optical path positioning mechanism (9) comprises a rotating disk (27) arranged at the moving end of the Z-axis driving member (6) and connected to the driving member, a lateral adjustment block (28) is arranged on the side of the front face of the rotating disk (27), and a longitudinal adjustment block (29) is arranged on the line connecting the lateral adjustment block (28) and the center of the rotating disk (27); a lateral adjustment plate (30) is arranged on the front side of the rotating disk (27) and is elastically and movably connected to the moving end of the Z-axis driving member (6) in a lateral direction, and a lateral positioning opening (31) for accommodating the lateral adjustment block (28) and the longitudinal adjustment block (29) is arranged on the lateral adjustment plate (30), and two sides of the lateral positioning opening (31) are provided with symmetrical arc-shaped positioning surfaces (32), and the radius of the arc-shaped positioning surface (32) is The distance from the lateral adjustment block (28) to the center of the rotating disk (27) is equal, and the center of the arc-shaped positioning surface (32) and the center of the rotating disk (27) are located on the same horizontal line; the upper and lower ends of the lateral positioning opening (31) are both provided with a vertically arranged lateral drive opening (33), and the lateral drive opening (33) is adapted to the lateral adjustment block (28); the front side of the lateral adjustment plate (30) is provided with a vertically movable vertical adjustment plate (35), the back side of the vertical adjustment plate (35) is provided with a horizontally arranged strip drive groove (34), and the longitudinal adjustment block (29) passes through the lateral positioning opening (31) and is matched with the strip drive groove (34); the acquisition camera (10) is connected to the vertical adjustment plate (35).

8. The perovskite laser scribing device according to claim 7, characterized in that: A symmetrically arranged positioning member (36) is provided on the movable end of the Z-axis driving member (6); a movable plate (37) movably connected to the corresponding side positioning member (36) is provided on the side of the lateral adjustment plate (30); a baffle (38) is provided at the end of the movable plate (37); and a spring (39) is provided between the baffle (38) and the corresponding side positioning member (36).

9. The perovskite laser scribing device according to claim 7, characterized in that: The arc angle of the arc-shaped positioning surface (32) is less than 180°.

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