Method and device for forming structure on workpiece

Abstract

The invention relates to a device and a method for forming a structure on a workpiece by means of machining radiation, during which the workpiece is moved by means of a conveying device, correction data of the workpiece being detected by means of an optical sensor. The correction data comprises movement data of the workpiece and / or position data of a structure produced by the machining radiation on the workpiece, and wherein a deflection of the machining radiation by the deflection unit is determined, in particular corrected, by the control device on the basis of the correction data.

Description

[0001] In machining workpieces, it is known to structure the workpiece by electromagnetic machining radiation. Structuring can include modifying the workpiece by machining radiation and / or removing material by machining radiation, in particular ablating it.

[0002] Laser radiation is usually used as the processing radiation. Such structuring on workpieces by means of laser radiation is used in particular in the production of photovoltaic solar cells and in the production of printed circuit boards.

[0003] In order to achieve high productivity in production, it is known to process the workpiece by means of a processing beam while simultaneously moving the workpiece by means of a conveying device. In this way, in particular inline processing can be achieved.

[0004] The transport of the workpieces by means of a conveyor device during their processing has the disadvantage that fluctuations in the conveying speed and / or movements of the workpieces on the conveyor device, in particular rotations of the workpieces, lead to inaccuracies in the processing.

[0005] It is therefore known to detect the edge of a workpiece which has been approached by means of an optical sensor before processing by means of processing radiation. Such a device is described in EP 2940740 A1.

[0006] The object of the present invention is to provide a method and a device for forming structures on a workpiece using machining radiation, which method allows for greater precision when the workpieces are transported irregularly on a conveyor device.

[0007] This object is achieved by a method for structuring a workpiece by means of processing radiation according to claim 1 and by a device for structuring a workpiece by means of processing radiation according to claim 11. Advantageous embodiments of the method according to the invention are given in claims 2 to 10 and advantageous embodiments of the device according to the invention are given in claims 12 to 15.

[0008] The method according to the invention is preferably designed to be carried out by means of the device according to the invention, in particular the preferred embodiments of the device. The device according to the invention is designed to carry out the method according to the invention, in particular the preferred embodiments of the method.

[0009] The invention is based on the recognition that, in order to avoid position deviations when machining a workpiece by machining radiation, it is important to detect correction data of the workpiece by means of at least one optical sensor during the machining of the workpiece.

[0010] The method according to the invention for structuring a workpiece by means of processing radiation comprises the following processing steps:

[0011] In method step A, a workpiece is provided on a conveyor device. In method step B, the workpiece is moved along a movement path by the conveyor device and, while the workpiece is moved by the conveyor device, the workpiece is processed by processing radiation. The time of processing is controlled by a control device and, preferably, the position of the workpiece processed by processing radiation is controlled by an optical deflection unit for processing radiation controlled by the control device in order to form the structure.

[0012] Thus, in the method according to the invention, processing is performed in a known manner during transport by the transport device, thereby achieving high productivity and in-line processing. The time of processing is controlled by the control device in order to achieve processing at the desired processing position on the workpiece surface. Advantageously, an optical deflection unit for the processing radiation is additionally controlled by the control device, so that the processing radiation can be deflected by the optical deflection unit to different positions on the workpiece and / or the processing radiation can be deflected in such a way that the radiation is directed to a processing position within a defined period of time, whereby the radiation moves in the coordinate system of the device at the transport speed of the workpiece.

[0013] It is essential that in method step B, during the processing of the workpiece by the processing radiation, correction data of the workpiece are detected by at least one optical sensor. The correction data include movement data of the workpiece and / or position data of structures produced on the workpiece by the processing radiation. Based on the correction data, the time of processing and / or the deflection of the processing radiation by the deflection unit is determined, in particular corrected, by the control device.

[0014] The transport of workpieces by conveyors involves various sources of error which can lead to inaccuracies and, in particular, positional deviations when processing the workpieces by the processing beam: Modern conveyors also have fluctuations in the speed of movement, so that the estimation of the workpiece trajectory based on the usually constant conveyor speed can be wrong. Systems for measuring the conveying speed on a conveyor element, such as a conveyor belt of a conveyor, also have errors, since there can be slippage between the measuring system and the conveyor belt or the conveyor belt itself can have length changes. Furthermore, the workpiece can change position on the conveyor and relative to the conveyor element, such as the conveyor belt, in particular due to vibrations and tremors.

[0015] The method according to the invention makes it possible to correct these deviations, since correction data of the workpiece itself are detected during machining of the workpiece.

[0016] It is within the scope of the invention that the correction data include movement data of the workpiece. The change in position of the workpiece and thus the position during processing are determined from the movement data. The detection of the movement data can be achieved precisely and economically by optical sensors, as described in detail below.

[0017] It is also within the scope of the invention that the correction data include position data of structures produced on the workpiece by the processing radiation. This results in the advantage that the positions of structures, in particular the distance between subregions of a structure or the distance between two individual structures produced by the processing radiation, can be compared with a predetermined value and a corresponding correction can be calculated for deflecting the processing radiation by the optical deflection unit in order to avoid deviations during further processing.

[0018] It is also within the scope of the invention to detect both movement data of the workpiece and position data of the structure produced on the workpiece by the machining radiation and to use these data for deflecting the machining radiation by the deflection unit.

[0019] In an advantageous embodiment of the method according to the invention, the time of the machining is additionally determined, in particular corrected, as a function of the correction data.

[0020] In an advantageous embodiment of the method according to the invention, method step B.1 is carried out in method step B, wherein the position of the workpiece is identified before the workpiece is processed by the processing radiation, and after method step B.1, in method step B.2, movement data of the workpiece are detected.

[0021] Thus, the position of the workpiece is initially detected in method step B.1. The workpiece trajectory can be calculated precisely by detecting the movement data in method step B.2.

[0022] It is particularly advantageous if the recording of the position data according to method step B.2 begins at the latest during the execution of method step B.1 and continues at least until the generation of the structure by the processing radiation, preferably until the end of the generation of the structure by the processing radiation.

[0023] This ensures that the movement data are detected uninterruptedly from the time of position detection until the time of machining, in particular the time of the end of machining, so that all changes in the workpiece position due to external influences are detected starting from the time of position detection.

[0024] In method step B.2, the movement data of the workpiece are advantageously detected by a plurality of optical detectors, in particular by a plurality of individual optical detectors, preferably by detectors arranged in an array.

[0025] The use of a plurality of optical detectors for detecting the movement has the advantage that detection can be carried out over larger sections and that by comparing the movement data, a rotation of the workpiece, in particular about an axis perpendicular to the conveying direction, can also be detected. In order to detect the movement of the workpiece precisely, it is advantageous if the optical detectors are arranged in an array, particularly preferably in a grid arrangement, in which case the detectors are arranged at the intersections of the grid in a grid having rectangular, preferably square, cells.

[0026] Preferably, the array has at least 2, in particular at least 3, preferably at least 30, in particular 32 detectors. Preferably, the array has rows oriented transversely to the conveying direction, preferably at least 2, preferably 4, preferably at least 3 sensors are arranged in each row. Preferably, the array has at least 2, preferably at least 4, in particular at least 8 rows.

[0027] In an advantageous development, in addition to the detectors for motion detection, the array has at least one detector for position detection, preferably a plurality of detectors for position detection.

[0028] In method steps B.1 and B.2, the characteristic data are advantageously detected by different optical detectors, in particular by detectors arranged in separate housings. The detectors can thus be arranged spatially spaced apart from one another.

[0029] In an advantageous embodiment, the detector array has a plurality of data processing units. It is particularly advantageous if each detector of the array has its own data processing unit for processing the raw signals measured by the detector, particularly preferably for outputting a digital measurement signal, preferably a speed signal, which indicates the measured workpiece speed in at least one dimension, preferably in two dimensions. Therefore, preferably each detector has a processor unit, preferably a signal processor (DSP), preferably with at least one microprocessor, and preferably with a program and data memory.

[0030] This results in the advantage that a particularly rapid calculation of the movement data of the workpiece is achieved by decentralized signal processing.

[0031] The device advantageously has at least one data line for the detectors leading to the control unit, so that a plurality of detectors of the array, preferably all detectors of the array, are connected in parallel to the control unit, thereby making it possible to read out the data of the detectors in parallel and achieve a higher processing speed when calculating the movement data of the workpiece.

[0032] In particular, detectors of different designs can be used and conventional commercially available detectors can be used in this case.

[0033] The control unit preferably has at least one processor unit, which preferably has one or more microprocessors, in particular an FPGA (field programmable gate array). In addition, the control unit preferably has at least one program and data memory connected to the processor unit.

[0034] The motion data of the workpiece are advantageously measured by means of a motion sensor on the side of the workpiece opposite the processing side of the workpiece, which is processed by the processing radiation. As a result, the motion measurement can also be carried out during the processing of the workpiece and the arrangement of the motion sensor is not spatially restricted by the beam path of the processing radiation or the optical components for the processing radiation.

[0035] The workpiece is preferably placed on a conveyor for processing and is processed from above by the processing radiation. The motion data of the workpiece are therefore advantageously detected from below. It is particularly advantageous if at least some of the motion sensors, preferably the array of motion sensors, particularly preferably all of the motion sensors are arranged on the side of the conveyor opposite the deflection unit, in particular below the conveyor.

[0036] To improve the measurement quality, an additional irradiation device, in particular an infrared irradiation device, is advantageously directed at the workpiece, in particular from above. Thus, when the correction data are detected, the workpiece is advantageously irradiated with infrared radiation, in particular from the side of the workpiece opposite the sensor. The device therefore preferably has a radiation source for infrared radiation, which is preferably arranged and designed to irradiate the workpiece from the side being processed.

[0037] Advantageously, in method step B.1, the position data of the workpiece are detected by at least one light barrier and in method step B.2, the movement data of the workpiece are detected by an optical tracking sensor. Light barriers and tracking sensors are standard components that are commercially available economically and at the same time with high measuring accuracy.

[0038] By using a camera or an optical micrometer to determine the position data of the workpiece, a higher degree of precision is achieved in position recognition.

[0039] It is therefore advantageous if in method step B.1 the position data of the workpiece (2) are detected by at least one position sensor selected from the group consisting of a light barrier, a camera, and an optical micrometer.

[0040] In an advantageous embodiment of the method according to the invention, in method step B, at least one image, in particular a spatially resolved image and / or a processed spatially resolved image, in particular a spatially resolved image processed by Fourier transformation, of the surface of the workpiece processed by the processing radiation is detected. By means of image analysis methods known per se, structures produced by the processing radiation can be localized in the spatially resolved image, so that position data of the structures can be determined from the spatially resolved image. The position of the structures produced on the workpiece by the processing radiation is therefore preferably determined by means of the detected spatially resolved image.

[0041] It is particularly advantageous if a plurality of images are recorded during the machining process, so that changes in the position of the structures produced by the machining radiation can also be determined.

[0042] Advantageously, a correction is made to the structure dimensions of the structure generated by the processing radiation, in particular to at least one distance between spaced-apart structure subregions of the structure generated by the processing radiation. Alternatively or preferably additionally, it is advantageous to use the distance of the structure detected by the spatially resolved image to correct at least one distance between a plurality of structures generated by the processing radiation and / or to correct the distance of the structure formed by the processing radiation to one or more edges of the workpiece. Deviations of the distance from a predetermined distance can thereby be detected and the processing time and / or the deflection of the processing radiation by the optical deflection unit can be corrected for further processing in order to reduce, preferably eliminate, the detected deviation.

[0043] During the detection of the correction data, the workpiece is advantageously irradiated, particularly preferably by infrared light. The device according to the invention therefore preferably has an irradiation device, particularly preferably an irradiation device designed to emit infrared radiation.

[0044] It is within the scope of the invention to use different types of processing radiation, in particular ion beams, for processing. Electromagnetic radiation, in particular laser radiation, is particularly preferably used. It is therefore particularly advantageous if in method step B the workpiece is processed using laser radiation. Laser radiation has a high energy density and a low divergence and is therefore particularly suitable for producing structures on workpieces.

[0045] Another source of error when machining workpieces by machining radiation is when the workpieces are not flat or have different height contours. The method according to the invention and the device according to the invention are particularly suitable for machining planar, in particular plate-like, workpieces, in particular for machining semiconductor substrates for producing components, in particular for producing photovoltaic solar cells.

[0046] In the method according to the invention, workpieces are therefore advantageously provided on the conveyor device, which workpieces are dimensionally stable workpieces, in particular flat workpieces, in particular plate-like workpieces, preferably semiconductor substrates, particularly preferably solar cells.

[0047] The device according to the invention is therefore advantageously designed for forming structures on a workpiece, a dimensionally stable workpiece, in particular a flat, in particular a plate-like workpiece, preferably a semiconductor substrate, particularly preferably a solar cell.

[0048] Such flat workpieces may have unevenness, so that when the workpiece is placed on the conveyor device, there are height differences between different locations of the workpiece, in particular between the center region and the edge of the workpiece.

[0049] Therefore, in an advantageous development of the method according to the invention, the height profile of the workpiece is detected, preferably the height profile of the machining side of the workpiece. The machining side of the workpiece is the side that is acted upon by the machining radiation. In addition, at least one of the following parameters is adjusted, in particular corrected, as a function of the height profile:

[0050] - Processing time;

[0051] - deflection of the processing radiation by a deflection unit;

[0052] - Focusing of the processing radiation by means of a focusing device.

[0053] It is particularly advantageous if the time of machining is adjusted, in particular corrected, and / or if the machining radiation is deflected by a deflection unit.

[0054] Depending on the angle at which the machining radiation strikes the workpiece surface, height differences that occur, in particular due to uneven workpieces, can lead to position deviations during machining. The machining time and / or the deflection of the machining radiation by the deflection unit are therefore advantageously adjusted, in particular corrected, in order to correct position deviations caused by height differences detected by the height profile.

[0055] During machining, a focusing device is advantageously used in order to focus the machining radiation onto a machining point on the workpiece. This allows a higher energy density to be achieved and a smaller structure to be formed. When the height profile of the workpiece is known, the focusing device is preferably controlled in such a way that the machining radiation is always focused onto the surface of the workpiece.

[0056] Incorrect focusing of the machining radiation due to height differences in the workpiece, in particular curvature of a flat workpiece, is thereby avoided.

[0057] The aforementioned object is also achieved by a device for structuring a workpiece by means of processing radiation according to claim 11 .

[0058] The device according to the invention has a conveying device for moving a workpiece along a movement path, a radiation source for generating a processing radiation and a control device for controlling the processing time and / or the deflection of the processing radiation for processing the workpiece. In addition, the device has an optical sensor for detecting position data of the workpiece.

[0059] It is important that the optical sensor is designed as a motion sensor for detecting the movement of the workpiece and that the device additionally has at least one optical position sensor for detecting position data of the workpiece. It is within the scope of the invention to use a sensor that is itself technically designed as a motion sensor as a position sensor. In this way, the coverage of the sensor field of the motion sensor can be measured in order to measure the position of the workpiece relative to the motion sensor, and the motion sensor is designed in such a way that the detector that is itself designed as a motion sensor behaves as a position sensor.

[0060] The device according to the invention thus makes it possible to detect the position of the workpiece by means of a position sensor and the movement by means of a motion sensor, so that starting from the detected position a workpiece trajectory can be determined with the aid of the data of the motion sensor, which corresponds to the actual trajectory, i.e. deviations due to speed changes can be taken into account when the workpiece is transported by a conveyor device or moves on a conveyor device.

[0061] The method according to the invention has the advantage that an exact alignment of the machining radiation to the desired machining location on the workpiece surface is achieved. This makes it possible to use optical elements, such as cylindrical lenses, as explained below.

[0062] Therefore, the detection range of the position sensor is arranged before the detection range of at least a subset of the motion sensors, preferably before the detection range of all the motion sensors, along the conveying direction of the conveying device. As a result, when the workpiece is transported, the workpiece trajectory can be calculated using the data of the motion sensor from the moment when the position is detected by the position sensor.

[0063] At least a subset of the motion sensors, preferably all the motion sensors, are advantageously designed as tracking sensors. Alternatively or preferably in addition, the position sensor is designed as a light barrier. As explained above, commercially available tracking sensors and light barriers can be used here, which economically enable high-precision measurements. As explained above, a higher precision is achieved in an advantageous embodiment in which the position sensor is designed as a camera or an optical micrometer.

[0064] Optical tracking sensors are known in particular for use in computer mice for motion recognition. Such tracking sensors are advantageously used as optical tracking sensors.

[0065] It is therefore advantageous if the optical tracking sensor is designed as described in US Pat. No. 7,057,148 B2.

[0066] The optical deflection unit preferably has one or more movable mirrors, in particular galvanometric mirrors. In another advantageous embodiment, the deflection unit has at least one polygonal reflector wheel. It is particularly advantageous if the deflection unit is designed with a combination of at least one galvanometric mirror and a polygonal reflector wheel.

[0067] As explained above, it is advantageous to take into account the height profile of the workpiece. The device according to the invention therefore advantageously has a height profile measuring unit for determining the height profile of the workpiece arranged on the conveyor device.

[0068] The height profile measuring unit is preferably designed as a triangulation sensor, and the height profile is preferably determined by triangulation using laser line or fringe light projection.

[0069] Given the knowledge of the height data, the machining time and / or the deflection of the moving radiation by the optical deflection unit can be corrected in order to correct the machining position on the workpiece.

[0070] The device according to the invention advantageously has a focusing device for the processing radiation. As a result, as described above, the energy density can be increased and structures with smaller dimensions can be produced. The control unit is advantageously designed to cooperate with the height profile measuring unit and the focusing device in order to control the focusing unit as a function of the height profile data of the height profile measuring unit.

[0071] This ensures that, in the case of height differences on the workpiece, in particular in the case of unevenness of the workpiece, the focus of the moving beam is corrected, in particular so that it always lies on the surface of the workpiece or follows it.

[0072] The focusing unit advantageously has passive components, in particular an optical lens with a fixed focal length, and active components, in particular a liquid lens or a mirror system, which moves the focus as a function of the height data of the height profile measuring unit. The focusing unit is advantageously designed and controlled as described in Jahn, Axel, 3-dimensional beamshaping for dynamic adjustment of focus position and intensity distribution for laser welding and cutting, http: / / publica.fraunhofer.de / documents / N-645639.html.

[0073] The device according to the invention is preferably designed to carry out the method according to the invention, in particular to carry out advantageous embodiments of the method.

[0074] Therefore, the optical sensor is advantageously configured such that during processing of the workpiece by means of processing radiation, correction data of the workpiece are detected by at least one optical sensor of the device, the correction data comprising movement data of the workpiece and / or position data of structures produced on the workpiece by the processing radiation, and the control device is configured to cooperate with the optical sensor so that the deflection of the processing radiation caused by the deflection unit is adjusted, in particular corrected, by the control device according to the correction data.

[0075] The advantages described above with respect to claim 1 are thereby achieved.

[0076] It is within the scope of the invention that the conveyor device is designed for conveying the workpiece along a non-linear path of motion. It is particularly within the scope of the invention that the workpiece is conveyed on a curved, in particular circular, path of motion. It is also within the scope of the invention that the structure is formed on the workpiece, in particular on a strip-shaped workpiece, by a roller-to-roller method (R2R method). For integration into an in-line process, it is advantageous if the conveyor device is designed for conveying the workpiece on a linear path of motion.

[0077] As described above, the method according to the invention and the device according to the invention make it possible to load the workpiece with processing radiation at the desired position on the workpiece surface with great positional accuracy. This can be combined in a particularly advantageous manner with optical systems that produce smaller structures due to the large numerical aperture, but have only a small imaging area / field of view, in particular microlens arrays or cylindrical lenses. By transporting the workpiece, small structures can also be produced in a dispersed manner over a large area. In principle, it is known that cylindrical lenses can be advantageously used to form structures on a workpiece by processing radiation, as described, for example, in Khan et al. Formation of thin laser ablated contacts using cylindrical lens, https: / / doi.org / 10.1063 / 5.0056740.

[0078] It is therefore advantageous if an optical element, in particular an optical lens, preferably a cylindrical lens, is arranged in the beam path of the processing radiation between the deflection unit and the workpiece for focusing the processing radiation. The optical element, preferably the cylindrical lens, is preferably arranged close to the workpiece, in particular at a distance of less than 20 cm, more preferably less than 10 cm, in particular less than 5 cm from the workpiece. This allows a particularly narrow design to be realized.

[0079] Advantageous features and preferred embodiments are described below with reference to examples and drawings.

[0080] Figure 1 A first exemplary embodiment of a device according to the invention for structuring a workpiece by means of processing radiation is shown;

[0081] Figure 2 Show Figure 1 A top view of a sensor unit of the device shown in;

[0082] Figure 3 showing a top view of a machined workpiece; and

[0083] Figure 4 A second embodiment of the device according to the invention is shown.

[0084] All drawings show schematic, not-to-scale representations. In the drawings, the same reference numerals designate the same or identically acting elements.

[0085] exist Figure 1 and Figure 4The embodiment of the device according to the invention for forming structures on a workpiece by means of processing radiation, shown in a side view in FIG. 1 , is designed for processing a semiconductor substrate by means of laser radiation. The semiconductor substrate forms a precursor for producing photovoltaic solar cells. The precursor has a substrate in the form of a silicon wafer, on which a dielectric layer, in the present case a silicon oxide layer, is formed on the processing side located at the top in the figure. Using the processing radiation designed as laser radiation, a plurality of parallel straight structures are formed by laser ablation. These structures thus appear as linear openings in the dielectric layer.

[0086] exist Figure 1 The first embodiment of the device according to the invention for forming structures on workpieces by processing radiation, shown in FIG. 1 , has a conveyor device 1 for moving workpieces 2, which in the present case are designed as precursors for producing solar cells as described above. The conveyor device 1 has a conveyor belt on which the workpieces 2 are placed and correspondingly Figure 1 and Figure 4 The arrow direction shown in the figure moves from left to right along a straight line track.

[0087] exist Figure 1 and 4 1 and 2 show a side view of the device, so that only one edge of a planar workpiece 2 is shown in each case.

[0088] according to Figure 1 The device further comprises a radiation source 3 designed as a laser for generating processing radiation designed as laser radiation. In the present case, the laser is designed as a solid-state laser with a wavelength of 1064 nm and a pulse duration of 4 ns.

[0089] The device also has a deflection unit 4 which, in the present case, has a motor-rotatable mirror in order to deflect the laser beam 3a of the radiation source 3 perpendicularly to the conveying direction and perpendicularly to the upper processing side of the workpiece 2 and thus perpendicularly to the workpiece 2. Figure 1 The drawing plane in .

[0090] Furthermore, the device has an optical sensor.

[0091] A position sensor 5 is arranged in the transport direction upstream of the region of the device in which the workpiece 2 is processed by the laser beam 3 a.

[0092] The position sensor 5 has a plurality of light barriers which are arranged perpendicularly to the conveying direction and thus perpendicularly to the Figure 1 The drawing plane in is set along a straight line.

[0093] For this purpose, a reflector is arranged in a region of the conveyor device 1 below the workpiece 2 transported by the conveyor device. The conveying element of the conveyor device 1, in the present case a conveyor belt, is designed so that no elements of the conveyor belt are arranged in the region of the reflector, so that the position sensor 5 is located in the region of the reflector. Figure 1 The optical path between the housing 5 arranged on the top and the reflector arranged in the conveying device 1 is blocked only by the workpiece 2 .

[0094] Thus, the moment when the leading edge of the workpiece along the conveying direction blocks the optical path of the grating is detected by the position sensor 5. In addition, the tilted position of the workpiece can also be detected by the time difference of blocking each grating arranged along a straight line perpendicular to the conveying direction, as long as the leading edge of the workpiece is not perpendicular to the conveying direction. Thus, the absolute position of the workpiece 2 relative to the device is detected by the position sensor.

[0095] The optical sensor further comprises a motion sensor array 6. The motion sensor array 6 has a plurality of optical tracking sensors 6a, which are arranged at the intersections of a square grid in the present case. Figure 2 , a top view of the motion sensor array 6 is shown from above, in which the optical tracking sensors are each indicated by a circle. The optical tracking sensor 6a in the upper left corner is denoted by a reference numeral as an example.

[0096] The optical tracking sensor is designed in the present case as described in US Pat. No. 7,057,148 B2. In the present case, a single tracking sensor consists of an optical detector having 30x30 pixels, an integrated illumination device and a microcontroller containing a digital signal processing unit for calculating movement data.

[0097] Thus, from the moment the position of the workpiece is detected by the position sensor 5 at least until the moment the workpiece is processed by the laser beam 3a, the movement of the workpiece 2 is detected by the optical tracking sensor of the motion sensor array 6. Since a plurality of optical tracking sensors 6a are provided, the movement of the workpiece over time and also the rotation of the workpiece can be detected by the difference in movement speed and in particular the component of the movement speed perpendicular to the conveying direction.

[0098] The detection range of the optical tracking sensor 6 a is therefore arranged behind the detection range of the position sensor in the conveying direction.

[0099] exist Figure 3 , a workpiece 2 is shown in a top view from above, which has already been completely processed. The recesses that have been produced by laser ablation using the laser beam 3a are marked by black parallel lines. During processing, straight recesses are produced parallel to the conveying direction. However, Figure 1In the device shown in FIG. 1 , as described above, the laser beam can only be moved perpendicularly to the conveying direction by the deflection unit 4. However, in order to form the recesses, the movement of the laser beam and the ablation of the dielectric layer are carried out at a significantly higher speed than the movement speed of the workpiece 2 on the conveyor device 1. As a result, adjacent segments of the structure can always be produced in a sequential order. As a result, due to the extension of the ablation produced by the laser parallel to the movement direction, recesses that overlap in the conveying direction are produced step by step for each structure, so that a continuous straight recess is formed for each structure.

[0100] According to Figure 1 and Figure 4 The devices of the exemplary embodiments shown in each have a control device 7. The control device is connected to the optical sensor in order to acquire the measurement data of the optical sensor, and is also connected to the radiation source 3 in order to switch the radiation generation on and off, and is connected to the deflection unit in order to control the deflection of the laser beam 3a by means of the deflection unit.

[0101] For the sake of greater clarity, the connection to the motion sensor array 6 is not shown graphically.

[0102] according to Figure 1 An apparatus is configured to implement an embodiment of the method according to the invention:

[0103] In method step A, the workpiece 2 is provided on the conveyor device 1. Method step B is performed by moving the workpiece 2 along a straight line path indicated by an arrow by the conveyor device 1 and processing the workpiece 2 by processing radiation designed as a laser beam 3a during the movement of the workpiece 2 by the conveyor device 1. The time of processing is controlled by the control device 7 and the position of the workpiece processed by the processing radiation is controlled by the optical deflection unit 4 controlled by the control device 7, so that a laser beam 3a is formed in the process. Figure 3 The parallel structure of the straight lines is shown in FIG.

[0104] It is essential that in method step B, during the machining of the workpiece by means of the machining radiation, correction data of the workpiece are detected by means of the sensors 5 and 6 .

[0105] In the present case, the correction data include position data detected by the position sensor 5 and movement data of the workpiece 2 detected by the optical tracking sensor 6 a of the movement sensor 6 .

[0106] The time of machining and / or the deflection of the machining radiation by the deflection unit 7 are corrected by the control device as a function of the correction data.

[0107] If, for example, multiple light barriers of the position sensor 5 detect that the front edge of the workpiece 2 is not perpendicular but inclined relative to the conveying direction, the time for generating the structure is changed accordingly, because for the workpiece 2 that enters the processing area at an angle, only one structure is first formed and then an increasing number of structures are formed in order to ensure that the starting points of the structures from the edge of the workpiece have uniform spacing.

[0108] Furthermore, the deflection of the laser beam 3a by the deflection unit 7 is corrected, since the structure must be formed as a structure extending obliquely in the coordinate system of the processing device corresponding to the angle between the front edge of the workpiece 2 detected by the position sensor 5 and the conveying direction, so as to form a structure on the workpiece 2 extending parallel to the side edge of the workpiece 2 or perpendicular to the front edge of the workpiece.

[0109] Figure 4 A second embodiment of the device according to the invention is shown in FIG. The important elements and functions are identical to those of the first embodiment. Therefore, in order to avoid repetition, only the main differences are described below:

[0110] Figure 4 The position sensor 5 ′ of the device shown in is designed as a spatially resolving camera which, in the present case, has a CMOS chip.

[0111] according to Figure 4 The deflection unit 4' of the device has two galvanometric mirrors which enable deflection in any spatial direction along the processing plane, so that the laser beam 3a can be deflected not only with a component perpendicular to the conveying direction of the conveying device 1, but also with a component parallel to the conveying direction.

[0112] In a variant of this embodiment, a combination of a polygonal reflector wheel and a galvanometer is used as the deflection unit 4' in order to enable the light to move particularly quickly parallel to the workpiece and perpendicular to the direction of movement. In this case, the galvanometer is responsible for the correction of the movement in the transport direction, while the light moves uniformly perpendicular to the transport direction. The advantage of this embodiment is the possibility of realizing a particularly large processing area at a high processing speed with a large numerical aperture.

[0113] In addition, a focusing device 8 is provided on the deflection unit 4 in order to focus the laser beam 3a onto the workpiece 2. Figure 4 Located on the upper processing side.

[0114] In addition, according to Figure 4 The device has a height profile measuring unit 9 in order to measure the height profile of the machining side of the workpiece 2 .

[0115] The position sensor 5 ′, the focusing device 8 and the height profile measuring unit 9 are likewise connected to the control unit 7 .

[0116] exist Figure 4 In the device shown in , images of the processing area can thus be captured in a continuous sequence by the position sensor 5' designed as a camera. The front edge of the workpiece 2 is detected by image analysis. With these data, the position of the workpiece 2 can thus be detected when entering the processing area of ​​the device, and in particular the inclined position of the front edge of the workpiece 2 entering, as long as this front edge is not perpendicular to the conveying direction of the conveying device 1. This makes it possible to make corrections as already explained for the first embodiment.

[0117] In addition, Figure 4 The device shown in FIG. 5 makes it possible to detect the position of the structures generated by the processing radiation by means of a position sensor 5'. In the present exemplary embodiment, the spacings of the individual structures relative to one another and to the edge of the workpiece 2 are predetermined. The spacings between the structures and the spacings to the edge can be determined by image analysis during the creation of the structures. If the spacings do not correspond to the predetermined spacing values, the deflection of the laser beam by the deflection unit 4' is corrected in order to produce the correct spacing at least in the following processing.

[0118] according to Figure 4 The device additionally has a height profile measuring unit 9. The height profile measuring unit is designed in the present case to detect a two-dimensional height profile of the workpiece 2. For this purpose, the height profile measuring unit is designed in the present case as a laser triangulation measuring head.

[0119] The height profile of the workpiece 2 determined by the height profile measuring unit 9 is transmitted to the control device 7 and the control device controls the focusing device 8 accordingly so that the focus is always at the height given by the height profile at the current processing position and is therefore always on the surface of the processing side of the workpiece 2.

[0120] according to Figure 4 The device additionally has Figure 1 The described motion sensor array 6 is used for detecting motion data. As a result, redundant information is present about the position and motion of the workpiece 2. Thus, by means of a correction function, for example by calculating an arithmetic mean, the accuracy can be increased when detecting the characteristic data of the workpiece.

[0121] In a variant of an embodiment of the device according to the invention, characteristic data are detected exclusively by a position sensor 5 ′ which detects position data of a structure produced on the workpiece by the machining radiation, in the present case a linear recess produced on the workpiece 2 by the laser beam 3 a.

[0122] exist Figure 4 In the embodiment shown in , the laser beam 3a is deflected by the deflection unit 4 onto the cylindrical lens 10. The cylindrical lens 10 is oriented with the cylindrical axis transverse to the conveying direction. The use of a cylindrical lens makes it possible to form a particularly narrow structure, in particular a narrow line parallel to the cylindrical axis of the cylindrical lens. The cylindrical lens 10 has a particularly short focal length, in the present case about 150 mm, and can therefore be combined with the conveying system in a particularly advantageous manner, because due to the movement of the workpiece only a very small movement of the light in the conveying direction is ensured. Since the surface to be processed is not restricted in the conveying direction, very small structures can be realized on a large surface. The distance between the cylindrical lens 10 and the workpiece 2 is in the range of 1 cm to 5 cm.

[0123] Reference numerals list

[0124] 1 Conveying device

[0125] 2 Workpiece

[0126] 3 Radiation sources

[0127] 3a Laser beam

[0128] 4. 4' deflection unit

[0129] 5. 5' position sensor

[0130] 6 Motion Sensor Array

[0131] 6a Optical Tracking Sensor

[0132] 7 Control Devices

[0133] 8 Focusing device

[0134] 9 Height profile measurement unit

[0135] 10 Cylindrical lens

Claims

1. A method for forming a structure on a workpiece (2) by processing radiation, The method has the following steps: a. Providing a workpiece (2) on a conveying device (1); b. moving the workpiece (2) along a motion trajectory by the conveying device (1), and While the workpiece (2) is being moved by the transport device (1), the workpiece (2) is processed by the processing radiation, the time of processing being controlled by a control device (7) and the position of the workpiece (2) being processed by the processing radiation being preferably controlled by an optical deflection unit (4, 4') for the processing radiation controlled by the control device (7) in order to form the structure, It is characterized in that In method step B, during the processing of the workpiece (2) by means of processing radiation, correction data of the workpiece (2) are detected by means of at least one optical sensor. The correction data include movement data of the workpiece (2) and / or position data of structures produced on the workpiece (2) by the processing radiation, and The control device (7) determines, in particular corrects, the deflection of the processing radiation by the deflection unit (4, 4') based on the correction data.

2. The method according to claim 1, It is characterized in that In method step B, before processing the workpiece (2) by means of the processing radiation, in method step B.1, the position of the workpiece (2) is detected, and after method step B.1, in method step B.2, movement data of the workpiece (2) are detected.

3. The method according to claim 2, It is characterized in that The acquisition of the movement data according to method step B.2 begins at the latest during the performance of method step B.1 and continues at least until the generation of the structure by the processing radiation, preferably until the end of the generation of the structure by the processing radiation.

4. The method according to any one of claims 2 to 3, It is characterized in that In method step B.2, movement data of the workpiece (2) are detected by means of a plurality of optical detectors, in particular a plurality of individual optical detectors, in particular detectors preferably arranged in an array.

5. The method according to any one of claims 2 to 4, It is characterized in that In method steps B.1 and B.2, these characteristic data are detected by a plurality of optical detectors, in particular by detectors which are arranged in separate housings.

6. The method according to claim 5, It is characterized in that In the method step B.1, the position data of the workpiece (2) is detected by at least one position sensor selected from the group consisting of a grating, a camera, and an optical micrometer, and in the method step B.2, the motion data of the workpiece (2) is detected by an optical tracking sensor (6a).

7. The method according to any one of the preceding claims, It is characterized in that In method step B, at least one spatially resolved image of the surface of the workpiece (2) processed by the processing radiation is detected, in particular a processed spatially resolved image, in particular a spatially resolved image processed by Fourier transformation, and the position of the structure generated on the workpiece (2) by the processing radiation is preferably determined by means of the image.

8. The method according to claim 7, It is characterized in that Correction of structural dimensions of a structure produced by the processing radiation, in particular correction of at least one distance between spaced-apart structural sub-regions of a structure produced by the processing radiation, and / or correction of at least one distance between a plurality of structures produced by the processing radiation using the distance of the structures detected by the spatially resolved image, and / or correction of the distance of the structure formed by the processing radiation to one or more edges of the workpiece.

9. The method according to any one of the preceding claims, It is characterized in that In method step B, the workpiece (2) is processed by laser radiation.

10. The method according to any one of the preceding claims, It is characterized in that Detecting the height profile of the workpiece (2), preferably detecting the height profile of the processing side of the workpiece (2), and performing at least one of the following corrections based on the height profile: - the time of processing; - deflection of the processing radiation by the deflection unit (4, 4'); - focusing of the processing radiation by means of focusing means.

11. A device for forming a structure on a workpiece (2) by processing radiation, A conveying device (1) for moving the workpiece (2) along a preferably rectilinear motion path, a radiation source for generating processing radiation and a control device (7) for controlling the processing time and / or deflecting the processing radiation for processing the workpiece (2), and an optical sensor for detecting position data of the workpiece (2), It is characterized in that The optical sensor is designed as a motion sensor for detecting a movement of the workpiece (2), and the device additionally has at least one optical position sensor (5, 5') for detecting position data of the workpiece (2).

12. The device according to claim 11, It is characterized in that The detection range of the position sensor is arranged in the conveying direction of the conveying device (1) before the detection range of at least a subset of the motion sensors.

13. The device according to any one of claims 11 to 12, It is characterized in that At least a subset of the motion sensors are configured as tracking sensors, and / or The position sensor is designed as a light barrier, a camera or an optical micrometer.

14. The device according to any one of claims 11 to 13, It is characterized in that The device comprises a height profile measuring unit (9) for determining a height profile of the workpiece (2) arranged on the conveyor device (1), in particular, The device has a focusing device (8) for processing radiation, and the control unit is configured to cooperate with the height profile measuring unit (9) and the focusing device (8) so as to control the focusing device (8) based on height profile data of the height profile measuring unit (9).

15. The device according to any one of claims 11 to 14, It is characterized in that The optical sensor is designed to detect correction data of the workpiece (2) by at least one optical sensor during processing of the workpiece (2) by means of the processing radiation, the correction data comprising movement data of the workpiece (2) and / or position data of structures generated on the workpiece (2) by means of the processing radiation, and The control device (7) is designed to cooperate with the optical sensor so that the control device (7) corrects the processing time and / or the deflection of the processing radiation by the deflection unit (4, 4') based on the correction data.

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