A method for performing scanning field correction on at least one laser scanning device, a laser scanning device, a scattering pattern element, a scattering pattern holding device, and a scanning field correction system.

Abstract

The present invention relates to a method for scanning field correction of at least one laser scanning device (300), wherein the method comprises the following steps: - providing a scattering pattern element (30) on a processing plane (11), the scattering pattern element (30) having at least one scattering region (31) disposed in a scattering pattern (M); - scanning or scanning at least a portion of the scattering pattern element (30) on the processing plane (11) along scanner coordinates (x, y, z) by means of a laser beam (12) of the at least one laser scanning device (300), the laser beam being deflected at a deflection unit (10) and the processing plane. (11) Passing through at least one window (20), preferably protective glass; - Detecting scattered radiation (13), which can be generated by scattering and / or reflection when the laser beam (12) sweeps or scans the at least one scattering area (31); - Creating a contour map (K) by associating the detected scattered radiation (13) with scanner coordinates (x, y, z); - Comparing the contour map (K) with a reference image of the scattering pattern (M) and determining the deviation between the contour map (K) and the reference image of the scattering pattern (M); - Calculating a calibration function for calibrating the deflection unit (10) based on the determined deviation.

Description

Technical Field

[0001] The present invention relates to a method for scanning field correction of at least one laser scanning device according to claim 1, a laser scanning device according to claim 10, a scattering pattern element according to claim 15, a scattering pattern element holding device according to claim 19, and a scanning field correction system according to claim 23. Background Technology

[0002] Traditional scanning modules or laser scanning equipment can position the laser spot with high precision and repeatability in all three spatial directions within a certain working volume. The beam deflection required for this is usually achieved by two deflection mirrors, while focusing in the z-direction is mostly achieved by moving optical components or by changing the settings of the zoom lens.

[0003] Due to design and tolerance considerations, the two mechanical motion processes are nonlinear in spatial coordinates x, y, z, and therefore will result in distortion errors in the desired trajectory under linear control. Therefore, the control software must be pre-calibrated accordingly to guide the laser beam geometrically correctly, i.e., without distortion.

[0004] Due to the high precision requirements, the corresponding predistortion function for scanning field correction can only be determined experimentally.

[0005] This pre-distortion function for scanning field correction must be determined individually and manually for each laser scanning device. To do this, a pattern is applied to paper or metal using a processing laser in several different steps, and time-consuming measurements are taken.

[0006] Depending on the specific requirements of each laser scanning device, measurements are taken either visually or with the aid of an external measuring machine (such as a coordinate measuring machine). Therefore, traditional methods are relatively inaccurate (visual measurement) or extremely time-consuming (coordinate measuring machine). Summary of the Invention

[0007] Therefore, the objective of this invention is to provide a method that enables high-precision scanning field correction of a laser scanning device to be performed in a simple and reproducible manner.

[0008] Another objective of the present invention is to provide a further improved laser scanning device, which includes a deflection unit with calibrable scanning field.

[0009] Another objective of the present invention is to provide an improved scattering pattern element, by which a further improved method for scanning field correction of laser scanning equipment can be implemented, particularly advantageously.

[0010] Another objective of the present invention is to provide a scattering pattern holding device, which is particularly well suited for fixing scattering pattern elements, especially scattering pattern elements according to the invention, thereby preferably enabling the implementation of a method for scanning field correction of a laser scanning device.

[0011] Another objective of this invention is to propose a further improved scan field correction system.

[0012] The task of performing scanning field correction on at least one laser scanning device is solved by the technical solution of claim 1, the laser scanning device by the technical solution of claim 10, the scattering pattern element by the technical solution of claim 15, the scattering pattern element holding device by the technical solution of claim 19, and the scanning field correction system by the technical solution of claim 23.

[0013] The task is addressed in particular by a method for scanning field correction of at least one laser scanning device, the method comprising the following steps:

[0014] - A scattering pattern element is provided on a processing plane, the scattering pattern element having at least one scattering region disposed in the scattering pattern;

[0015] - Using the laser beam of the at least one laser scanning device, the laser beam sweeps / scans along the scanner coordinates, especially sweeps or scans, particularly preferably sweeps and / or scans at least a portion of the scattering pattern elements on the processing plane, the laser beam passing through at least one window, preferably at least one protective glass, between the deflection unit and the processing plane;

[0016] - Detecting scattered radiation, which can be generated by scattering and / or reflection of a laser beam as it sweeps / scans, especially sweeps or scans, particularly preferably sweeps and / or scans the at least one scattering region;

[0017] - Create a contour diagram by correlating the detected scattered radiation with the scanner coordinates;

[0018] - Compare the contour map with a reference image of the scattering pattern and determine the deviation between the contour map and the reference image of the scattering pattern;

[0019] - Calculate the calibration function for calibrating the deflection control unit based on the determined deviation.

[0020] The basic idea of ​​this invention is that the operator can check and, if necessary, adjust the calibration function or pre-distortion function of the laser scanning equipment already installed in the (laser) processing machine, as needed (or at regular intervals). Reasons for this include, for example, replacing components such as the laser source, photodiodes, disassembling and reinstalling other optical components (e.g., for cleaning purposes), but it can also be a routine inspection after a certain number of working hours. This allows for the identification and compensation of misalignments caused during operation by thermal or mechanical loads such as shock or vibration.

[0021] Therefore, users can achieve high accuracy in scan field correction at minimal cost. The necessary measuring equipment (here: scattering pattern element) can be simply placed on the processing plane to perform the required measurements and evaluations without further operator input, and the calibration function for scan field correction can be calculated fully automatically based on the contour map.

[0022] Contour plots are preferably understood as intensity (profile) plots. The amplitude of the contour plot corresponds to the amplitude of the photodiode signal (or integrating photodiode signal), for example, indicated by "counts", or the amplitude is normalized to 1 (normalized to the highest photodiode signal).

[0023] Another aspect of this invention is that calibration is performed using the (processing) laser or the (processing) laser beam itself, rather than using a (separate) calibration laser. This improves accuracy because when using a calibration laser, there is typically a deviation from the actual laser beam, and calibration is not performed under "normal conditions." Therefore, the heat generated, for example, during processing in the optical system of the scanning device (through high laser power), can be directly considered during calibration. Thus, calibration or scan field correction is largely unaffected by external influences.

[0024] In one embodiment, a portion of the scattered radiation propagates toward at least one segment of the window edge by reflection and / or scattering within the window between the upper and lower sides of the window, such that the scattered radiation exits from the window edge and can be detected there.

[0025] Reflection on the window and / or transmission of light through the window and / or multiple reflections on the upper and lower sides of the window are low-cost and simple methods to attenuate a dense laser beam so that the corresponding detector of the detection light is unsaturated. Furthermore, this arrangement can be implemented with particularly space-saving efficiency.

[0026] Furthermore, this method allows for the collection of a large amount of scattered light because the entire aperture is utilized. Thus, not only can scattered radiation (from the scattering pattern element) be collected from the direct field of view of the photodiode, but it can also be detected indirectly through reflection and / or scattering within the window. Therefore, this method or optical detection can be implemented substantially independently of direction.

[0027] In a preferred embodiment, the detection of scattered radiation is performed on at least one segment of the window edge.

[0028] The detector can be permanently set up in this way and does not need to be removed, for example, after calibration.

[0029] In one embodiment, the detection of scattered radiation is performed using at least one, preferably two, more preferably at least three photodiodes, with the photodiodes preferably distributed at equal intervals.

[0030] In other words, the photodiodes can be arranged circumferentially along the window such that they are spaced equally apart from each other.

[0031] Photodiodes are readily available at low cost and easily readable. Using multiple photodiodes can create uniform contour maps, especially when they are equidistant. The more photodiodes used, the larger the field of view / detection field. As the number of photodiodes increases, the origin of the scattered light becomes less important in creating a uniform contour map.

[0032] In one implementation, the amplitude of the contour map is substantially proportional to the detected scattered radiation.

[0033] Because contour maps have a relatively high signal-to-noise ratio, optimal and reproducible data evaluation can be performed. This allows for the accurate determination of the calibration function. Therefore, another advantage lies in the accuracy of interpolation and / or fitting. This also optimizes computational workload and computation time.

[0034] In one embodiment, the contour map includes a scattering pattern image corresponding to a distorted display of the scattering pattern of the scattering pattern element, such that the contour map has multiple scattering region images that can be assigned to, in particular, to a preferred plurality of scattering regions of the scattering pattern element in a one-to-one correspondence.

[0035] By using geometrically defined, preferably one-to-one, configurable properties, the orientation or identification of a scattering pattern element or at least a portion thereof can be reliably determined in a simple manner. Therefore, well-defined and easily identifiable configurable properties can save computational effort and time, thereby accelerating the calibration process. This is particularly important when calibrating two or more laser scanning devices, especially relative to each other, such as when using a single (unique or common) scattering pattern element on a (common) processing plane.

[0036] In one embodiment, the step of determining the deviation between the contour map and the scattering pattern includes steps of fitting and / or interpolating the contour map (preferably in part).

[0037] Therefore, the method can be automated using computational units and corresponding instructions for executing the method steps. This allows for optimization of calibration accuracy. Computation time can be further reduced by performing only partial fitting and / or interpolation (e.g., only on important or particularly high-contrast portions of the contour map).

[0038] In one embodiment, the step of determining the deviation between the contour map and the scattering pattern includes determining the centroid and / or center point and / or shape distortion of the contour map reference point, and in particular, the multiple scattering region images of the contour map.

[0039] Data evaluation can be further optimized by establishing reference points for contour maps. Specific (scattering) regions can be fitted / interpolated easily, in relatively few steps, with relatively little computation, or in a relatively short computation time. For example, the edges of a circle or its center are relatively less susceptible to noise contamination. Therefore, data evaluation can be accelerated and accuracy improved.

[0040] In one embodiment, the step of determining the deviation between the contour map and the scattering pattern includes the step of determining the deviation and / or shape distortion between a reference point of the contour map and a corresponding reference point of a reference image of the scattering pattern.

[0041] Data evaluation can be further optimized by determining reference points in a reference image of the scattering pattern. Specific (scattering) regions can be fitted / interpolated simply, in relatively few steps, with relatively little computation, or in a relatively short computation time. For example, the edges of a circle or its center are relatively less susceptible to noise contamination. Therefore, data evaluation can be accelerated and accuracy improved.

[0042] The task according to the invention is also solved by a laser scanning device comprising a scanning field calibrable deflection unit, the laser scanning device having:

[0043] - At least one deflection unit configured to scan, in particular scan or scan, especially scan and / or scan the processing area along predetermined scanner coordinates by means of a laser beam.

[0044] A scattering pattern element can be disposed on a processing plane, the scattering pattern element having at least one scattering region, the at least one scattering region being disposed in the scattering pattern;

[0045] - At least one window, preferably at least one protective glass, is disposed between the deflection unit and the processing area;

[0046] - At least one photodiode configured to detect scattered radiation, which can be generated by scattering and / or reflection of a laser beam as it sweeps across at least one scattering region of a scattering pattern element;

[0047] - A calculation unit, constructed to create a contour map by associating the detected scattered radiation with the scanner coordinates and to calculate a calibration function for calibrating the deflection unit based on the deviation of the contour map from a reference image of the scattering pattern.

[0048] This yields the same advantages as those described in the combined method. Contour map data evaluation can be performed using computational units via fitting and / or interpolation and / or contrast enhancement and / or thresholding analysis, along with further image processing steps.

[0049] In one embodiment, two, preferably at least three, photodiodes are disposed on a section of the window edge.

[0050] Photodiodes are readily available at low cost and easily readable. Using multiple photodiodes can create uniform contour maps, especially when they are equidistant. The more photodiodes used, the larger the field of view / detection field. As the number of photodiodes increases, the origin of the scattered light becomes less important in creating a uniform contour map.

[0051] In one embodiment, the at least one photodiode, preferably two, more preferably at least three photodiodes are configured and / or arranged to detect a portion of scattered radiation that propagates toward a section of the window edge by reflection and / or scattering within the window between the upper and lower sides of the window.

[0052] Reflection or scattering on the window and / or transmission of light through the window and / or multiple reflections on the upper and lower sides of the window are low-cost and simple methods to attenuate a dense laser beam so that the corresponding detector of the detection light is not saturated.

[0053] Furthermore, this arrangement can be implemented with particularly low space consumption. Moreover, a large amount of scattered light can be collected in this way because the entire aperture is utilized. Thus, not only can the scattered radiation (from the scattering pattern element) be collected from the direct field of view of the photodiode, but it can also be detected indirectly through reflection and / or scattering within the window. Therefore, this method or light detection can be implemented substantially independently of direction.

[0054] In one embodiment, the at least one photodiode is configured to output a measurement signal to a computing unit that is substantially proportional to the detected scattered radiation.

[0055] In a preferred embodiment, the amplitude of the contour plot is proportional to the detected scattered radiation or the measurement signal of the at least one photodiode.

[0056] Because contour maps have a relatively high signal-to-noise ratio, optimal and reproducible data evaluation can be performed. This allows for the accurate determination of the calibration function. Therefore, another advantage lies in the accuracy of interpolation and / or fitting. This also optimizes computational workload and computation time.

[0057] The objective according to the invention is also achieved by a scattering pattern element, which is used, in particular, for scanning field correction of a laser scanning device according to the method described above and / or, in particular, for a laser scanning device as described above.

[0058] The scattering pattern element is constructed in a plate shape, preferably made of glass or glass-ceramic, especially fused silica or... Alternatively, it may be made of Borofloat (heat-resistant glass) and have a scattering pattern comprising multiple scattering regions.

[0059] The scattering region is constructed as a roughened and / or printed surface area and / or aperture of the scattering pattern element, or is constructed within the volume of the scattering pattern element.

[0060] The scattering region is positioned in the scattering pattern such that the image of the scattering pattern or a portion thereof can be clearly identified with each rotation, shape distortion, mirroring, scaling, or translation.

[0061] The basic idea behind scattering pattern elements is to provide a "target" that will not be damaged even under high laser power irradiation. Therefore, laser scanning equipment can be calibrated directly using the (processed) laser beam. A separate calibration laser can be advantageously omitted.

[0062] This is difficult to achieve with any material due to the high laser power / intensity (e.g., >50W or >100W, such as CW or pulsed, like NIR, with a focal size (on the scattering pattern element) of approximately 40μm) and target precision.

[0063] Not only static errors of the scattering pattern elements, such as "deflection" caused by their own weight, flatness of the scattering area, positioning accuracy, and manufacturing accuracy, but also dynamic errors, such as thermal expansion during the measurement process, must be minimized and / or taken into account in the subsequent evaluation of contour map data.

[0064] In one embodiment, the scattering region includes a first marking region, preferably a substantially circular arrangement of the first marking regions, each of the first marking regions being surrounded by a plurality of second marking regions, preferably substantially circular, arranged in a second manner.

[0065] This allows for optimization of image recognition / image processing or data processing. For example, the difference between the first and second arrangements can be chosen such that patterns in contour maps can be effectively identified or fitted. Consequently, easily manufactured scattering pattern elements are also obtained overall, which simplify data processing due to their scattering patterns. Calibration can thus be performed quickly and accurately.

[0066] In one embodiment, the second arrangement of the plurality of second marking regions differs for at least two marking regions in the first marking region, preferably for at least three marking regions, and even more preferably for each marking region (especially in terms of the angular arrangement and / or number of the second marking regions).

[0067] Therefore, the orientation of a scattering pattern or scattering pattern can be detected by means of a contour map, especially the orientation of a scattering pattern or scattering pattern, and particularly preferred.

[0068] In one embodiment, the scattering region comprises a plurality of polygons, preferably rectangular, said polygons having different sizes and / or multiple, especially all polygons having preferably unique marking protrusions.

[0069] This method allows for the effective detection of the orientation of scattering patterns using contour maps.

[0070] The objective according to the invention is also achieved by a scattering pattern element holding device for holding scattering pattern elements, particularly those as described above, to provide scattering pattern elements on the processing plane of a laser scanning device, particularly the laser scanning device as described above, wherein the scattering pattern element holding device has:

[0071] - The base surface and the sidewalls surrounding the base surface form a cavity for the scattering pattern element holding device. The sidewalls are configured at the upper end such that the scattering pattern element can be fixedly supported at the upper end, so that the light from the laser scanning device can pass through the scattering pattern element and enter the cavity.

[0072] - At least one deflecting cone disposed on the base surface, the deflecting cone being configured and / or configured to absorb light incident on the deflecting cone and / or deflect it toward the inward direction of the sidewall, the inward sidewall being configured to absorb light incident on the inward sidewall.

[0073] Furthermore, the speed and accuracy of the method described above for calculating the calibration function for calibrating and controlling the deflection unit are determined, for example, by the achievable contrast. Contrast is determined by the potentially varying surface roughness of the scattering pattern element and the associated backscattering of laser radiation toward the photodiode. However, depending on the material of the scattering pattern element, approximately 90% to almost 100% of the laser power is transmitted through it. Tests have shown that approximately 10% less light is transmitted in the scattering region. Therefore, how this power is collected is crucial for both contrast and thermal management. Therefore, according to the invention, light is absorbed on the inner wall of the cavity of the scattering pattern element holding device after transmission through the scattering pattern element.

[0074] In one embodiment, the inner side of the sidewall and / or the deflection cone has a plurality of absorbing fins. The absorbing fins are preferably constructed as elements with a triangular cross-section. The absorbing fins may have a pyramidal shape.

[0075] This allows for effective light absorption. Consequently, the contrast of the contour map is further improved, thus reducing computation time and increasing the accuracy of the calibration function.

[0076] In one embodiment, the upper end of the sidewall is configured such that the scattering pattern element is supported in a floating manner. Floating support is understood as support for the scattering pattern element such that the scattering pattern element does not rest entirely against the fixed section on its lower side. A distance is preferably formed between the scattering pattern element and the deflection cone.

[0077] Preferably, the upper end of the sidewall is constructed in the shape of a shoulder, so that the scattering pattern element can be placed on the shoulder.

[0078] The sidewalls have, for example, a chamfer or an insert groove at the upper end.

[0079] It is also possible that the sidewall has three or four support protrusions, for example, one support protrusion on one side of the sidewall, for placing the scattering pattern element 30.

[0080] The corresponding chamfers, insertion slots, or support protrusions may be recessed (viewed from the top) if necessary, so that the scattering pattern element can be installed in such a way that the sidewall at the top 44 stabilizes or fixes the scattering pattern element in position to prevent (undesirable) movement.

[0081] Therefore, the scattering pattern element can be thermally and mechanically separated from the scattering pattern holding device, so that the thermal expansion of the scattering pattern holding device has no effect on the scattering pattern element or will not have any effect.

[0082] In one embodiment, the base surface of the deflection cone substantially covers the entire base surface, and / or the height of the deflection cone corresponds to at least half of the height of the sidewall, preferably at least 80% of the height of the sidewall.

[0083] In this way, light from different incident directions can be effectively guided to the inner wall, where it can be absorbed. This further improves the contrast.

[0084] In order to enable the scattering pattern element to be positioned at multiple locations, the scattering pattern element can preferably be movably supported. For example, the scattering pattern element holding device can be movably supported in the XY plane.

[0085] To allow for the movable support of the scattering pattern element and / or the scattering pattern element holding device, it can be arranged, for example, on a cross table or an XY table.

[0086] The objective according to the invention is also achieved by a scanning field correction system comprising at least one laser scanning device as described above and at least one scattering pattern element as described above for scanning field correction, and preferably including at least one scattering pattern element holding device as described above.

[0087] It should be noted that the features and advantages described in the scope of the method according to the invention, the laser scanning device according to the invention, and the scattering pattern element according to the invention also apply to the scanning field correction system according to the invention.

[0088] Features of the method, especially those involving the detection of photodiode signals or the evaluation / analysis of contour maps, can be transferred to the calibration system according to the invention by configuring appropriate devices to suit the implementation of the corresponding method features.

[0089] In one embodiment, the scanning field correction system includes at least two scattering pattern elements that differ in size and / or scattering pattern.

[0090] This allows for the verification or testing of the calibrated control of the deflection unit. It is also conceivable to calibrate the calibration function using a second calibration function. Therefore, the control accuracy of the deflection unit can be further improved.

[0091] In one embodiment, the scanning field correction system includes at least two laser scanning devices whose scanning fields at least partially overlap, and the laser scanning devices can be calibrated relative to each other by means of scattering pattern elements.

[0092] In the case of multiple laser scanning devices, the corresponding scanning fields may be twisted and / or tilted relative to each other, for example, due to inaccurate (tilted) mounting of the respective laser scanning heads. The relative accuracy of beam guiding among the multiple laser beams can be optimized by means of common, and especially mutually coordinated, calibration. Advantageous extensions are derived from the dependent claims. Attached Figure Description

[0093] The invention will now be described in further detail, features and advantages, which will be explained in more detail with reference to the accompanying drawings.

[0094] The features and combinations thereof, as shown in and described with reference to the accompanying drawings, can be used not only in the corresponding specific combinations, but also in other combinations or individually, without departing from the scope of the invention. The drawings are as follows:

[0095] Figure 1 A schematic diagram of an embodiment of a laser scanning device comprising three photodiodes according to the present invention is shown;

[0096] Figure 2 A top view of one embodiment of the scattering pattern element according to the present invention is shown;

[0097] Figure 3 A schematic diagram illustrating an embodiment of the arrangement of scattering pattern elements on a processing plane is shown, schematically illustrating the scanning of at least a portion of the scattering pattern elements on the processing plane along scanner coordinates by means of a laser beam;

[0098] Figure 4 A schematic diagram of a contour plot according to one embodiment is shown, which is obtained by associating detected scattered radiation with scanner coordinates;

[0099] Figure 5 A top view of an alternative embodiment of a scattering pattern element according to the present invention is shown;

[0100] Figure 6 A schematic diagram of a contour plot according to an alternative embodiment is shown, which is obtained by associating detected scattered radiation with scanner coordinates;

[0101] Figure 7 A cross-sectional view is shown of one embodiment of the scattering pattern element holding device according to the present invention;

[0102] Figure 8 A cross-sectional view is shown of an embodiment of a scattering pattern element holding device including a scattering pattern element according to the present invention;

[0103] Figure 9A cross-sectional view is shown of an alternative embodiment of the scattering pattern element holding device according to the present invention;

[0104] Figure 10 A schematic top view of a scattering pattern holding device according to an embodiment of the present invention is shown;

[0105] Figure 11 An embodiment of a calibration or scanning field correction method for a scanning field correction system is shown, the system comprising two laser scanning devices and a common processing plane;

[0106] Figure 12 An embodiment of a calibration or scan field correction method for a scan field correction system is shown, the system comprising multiple laser scanning devices and a common processing plane; and

[0107] Figure 13 An alternative embodiment of a method for calibrating or correcting a laser scanning device by moving scattering pattern elements to multiple locations is shown. Detailed Implementation

[0108] Figure 1 A schematic diagram of an embodiment of a laser scanning device according to the present invention is shown, comprising a scanning field correction system 200 according to the present invention.

[0109] Here, the laser scanning device includes at least one laser source for emitting a laser beam 12. Figure 1 (not shown in the image) and at least one deflection unit 10.

[0110] The deflection unit 10 may include, for example, a (deflection) mirror and a galvanometer scanner.

[0111] The laser beam 12 can move in three spatial coordinates x, y, z by means of the deflection unit 10 and, if necessary, additional (not shown) deflection units.

[0112] The motion of the laser beam 12 in the three spatial coordinates x, y, and z should be understood as the laser beam spot moving on the processing plane 11 in the x and y directions (parallel to the processing plane 11 and, if necessary, perpendicular to each other) by means of the at least one deflection unit 10. The possible focal point position can move / shift in the z direction (perpendicular to the processing plane 11).

[0113] A window 20 is provided between the deflection unit 10 and the processing plane 11. The window 20 may be, for example, a protective glass, which is used to direct the laser beam 12 into the working area in which the processing plane 11 is provided.

[0114] In one embodiment, the window serves to protect the scanner's interior from external contaminants (dust, smoke, (water) vapor). In an extended embodiment of the invention, the laser scanning device can be sealed shut by means of the window.

[0115] exist Figure 1 A scattering pattern element 30 is disposed on the processing plane 11. The scattering pattern element 30 has multiple scattering regions 31, which can be arranged in a pattern M.

[0116] According to Figure 1 In this embodiment, three photodiodes PD1, PD2, and PD3 are respectively disposed on the window edge 23 of the window 20.

[0117] In addition, a fourth photodiode (not shown) may be present, which is disposed opposite to, for example, the third photodiode PD3.

[0118] For the scanning field correction according to the present invention, the laser beam 12 can scan or scan the processing plane 11 or the scattering pattern element 30 disposed on the processing plane along the predetermined scanner coordinates x and y respectively.

[0119] Subsequently, the laser beam is either deflected by the pattern M of the scattering pattern element 30 according to the law of reflection (if the light does not hit one of the scattering regions 31) or diffusely scattered by the scattering region 31 or a portion thereof.

[0120] The laser 13 reflected and / or scattered (generally referred to herein as scattered radiation 13, which may also include the reflected light) passes through the lower side 22 of the window.

[0121] A portion of the scattered radiation 13 propagates toward at least one segment of the window edge 23 of the window 20 through (multiple) reflections and / or scatterings within the window 20 between the upper side 21 and the lower side 22 of the window, such that the scattered radiation 13 is emitted from the window edge 23 of the window 20 and can be detected there.

[0122] Contrast is generated in the scattered radiation 13 that is reflected / scattered back based on the different surface roughness of the scattering pattern element 30.

[0123] The scattered radiation 13 is collected by photodiodes PD1, PD2, PD3 oriented toward the window 20 (inside) and is associated with the scanner coordinates x, y, z.

[0124] If the photodiode signals of photodiodes PD1, PD2, and PD3 are combined / correlated with the scanner coordinates x, y, and z to form a contour map K, then a distorted and blurred image of the scattering pattern M will be generated based on the aforementioned distortion error.

[0125] The necessary calibration function can be calculated by comparing the contour map K with a known reference image of the scattering pattern M.

[0126] The following is combined with Figure 2 An embodiment of a scattering pattern element 30 having a scattering pattern M according to this embodiment is described in more detail.

[0127] The scattering pattern element 30 is configured in a plate shape and is preferably made of glass or glass-ceramic, especially fused silica or... They are made of materials such as Borofloat. These materials are particularly suitable for high-performance lasers because they have exceptionally high damage thresholds. Furthermore, these materials have low coefficients of thermal expansion, thereby minimizing thermal effects.

[0128] according to Figure 2 The scattering pattern element 30 is configured as a rectangle. However, according to the present invention, the scattering pattern element can also be configured as a circle or can have any shape, such as a star.

[0129] The scattering pattern element 30 is specifically configured to be transparent to the wavelength of the laser beam 12 in order to avoid damage, for example, by absorbing light.

[0130] As an alternative, the scattering pattern element 30 can also be made of, for example, paper or cardboard or metal (for lower laser power).

[0131] The scattering pattern element 30 has a scattering pattern M on its surface, which includes a plurality of scattering regions 31, which are configured as roughened (e.g., by etching or sandblasting) and / or printed (surface) areas of the scattering pattern element 30.

[0132] Alternatively or additionally, the scattering region 30 may be at least partially disposed within the volume of the scattering pattern element 30. For example, such a scattering region can be introduced by laser engraving. It is also conceivable that the scattering region 30 may include holes (apertures).

[0133] The scattering region 31 is arranged in the scattering pattern M such that the (arbitrary) image of the scattering pattern M has a clearly identifiable orientation in each rotation, shape deformation, mirroring, scaling, or translation. Of course, according to the invention, alternatively, the scattering region 31 can be configured to be non-scattering, while the remaining regions of the scattering pattern element 30 can be configured to be scattering. Therefore, the design according to the invention can also form a "negative".

[0134] Therefore, the scattering region 31 may include a first arrangement of the first marking region 32 and a second arrangement of the second marking region 33.

[0135] According to Figure 2In one embodiment, the first marking region 32 is constructed as a circle, and these circles are arranged in a regular 3×3 pattern on the surface of the scattering pattern element.

[0136] Each first marked region 32 is surrounded by multiple second marked regions 33.

[0137] The second arrangement of the plurality of second marking regions 33 differs for at least two of the first marking regions 32, preferably for at least three of the first marking regions, and even more preferably for each of the first marking regions (especially in terms of the angular arrangement and / or number of the second marking regions 33).

[0138] This allows each first marked region 32 to be clearly identified. This provides a clear (geometric) configurable property (one-to-one correspondence) for the pattern M, so that the image of the scattering pattern M has a clearly identifiable orientation in each rotation, shape distortion and mirroring, scaling or translation.

[0139] To simplify the fabrication of image processing / recognition and scattering pattern elements, for example, only circles can be selected as the marking areas. This allows for any type of mask-related fabrication (sandblasting, etching) without "islands." Another advantage lies in "interpolation" / "fit accuracy," as the determination of the circle's center is less affected by noise-contaminated edges.

[0140] According to Figure 3 The embodiments schematically show a laser beam 12, aided by a laser scanning device, sweeping or scanning at least a portion of the scattering pattern elements 30 on the processing plane 11 along the scanner coordinates x, y, z or corresponding trajectories.

[0141] The scattering pattern elements can be scanned more frequently (sequentially), for example, four times, to improve contrast. The scanning order (or starting point), curve shape, or scanning speed can also be changed.

[0142] The contour map K is calculated based on the correlation between the scanner coordinates x, y, z and the photodiode signals detected for each scanner coordinate (each scanner coordinate x, y, z has a photodiode signal data record).

[0143] Figure 4 This diagram illustrates a contour plot K according to one embodiment, which measures the detected scattered radiation 13 (see...). Figure 1 ) and according to Figure 2 The scanner coordinates x, y, z on the scattering pattern element 30 in the embodiment (see [reference]). Figure 3 It is obtained through association.

[0144] The contour map K has coordinates x', y', z', where coordinates x' and y' essentially correspond to the scanner coordinates x, y, and z (see [reference]). Figure 3 And z' represents the magnitude of the contour plot.

[0145] The amplitude z' of contour plot K corresponds to multiple photodiodes PD1, PD2, PD3 (see...) Figure 1 The integral and / or average (e.g., averaged over multiple scans) of the signal.

[0146] For this purpose, a (basically) conventional analog-to-digital conversion is set up so that the unit of amplitude z' is, for example, expressed as "counts" or amplitude z' is normalized to 1 (normalized to the highest photodiode signal).

[0147] The contour plot K thus shows a (distorted) image of the scattering pattern 30 or a scattering pattern image M', which corresponds to a distorted display of the scattering pattern M of the scattering pattern element 30.

[0148] Therefore, the contour map K has multiple scattering region images 31', which can (preferably explicitly / one-to-one correspondence) be assigned to multiple scattering regions 31 of the scattering pattern element 30.

[0149] The contour map K is compared with a reference image (not shown) of the scattering pattern element 30 on the calculation unit.

[0150] For example, a reference image of the scattering pattern element 30 can be generated by means of a high-resolution photograph of the scattering pattern element 30 or by means of measurement of the scattering pattern element 30 by a coordinate measuring machine.

[0151] For example, it is conceivable to use raw data (coordinate raw data) as a reference image for the scattering pattern element 30, which is used in a (laser) printing method to form the scattering pattern M of the scattering pattern element 30.

[0152] To determine the deviation of the contour plot K from the scattering pattern M or from the reference image of the scattering pattern element 30, different fitting and / or interpolation methods can be used. Optionally, other image processing / data processing steps, such as contrast enhancement and / or thresholding analysis, can be performed.

[0153] In order to determine the deviation, in particular, the steps described in the preceding paragraphs are used to determine the reference points of the contour map, such as the centroid and / or center point and / or shape distortion (e.g., “elliptical” instead of circular) of the multiple scattering regions of the contour map K.

[0154] A grid can be generated from contour map reference points, where each contour map reference point includes information about its x and y positions as well as the (optimal) focal position.

[0155] The predistortion function or calibration function can be calculated by comparing the contour map reference point with the undistorted regular reference image (or the predetermined reference point of the reference image) of the scattering pattern M of the scattering pattern element 30.

[0156] The calibration function, for example, is used to compensate for pincushion-barrel distortion or other distortions, and it may be used when controlling the deflection unit 10 (see [link]). Figure 1 )produce.

[0157] The calibration function, including the z-value (=(optimal) focal position), is accomplished by interpolation between the corresponding reference points of the contour map reference point and / or the reference image of the scattering pattern M.

[0158] Figure 5 A top view showing an alternative embodiment of a scattering pattern element 30 having a scattering pattern M according to the present invention.

[0159] according to Figure 5 An embodiment of the scattering pattern element 30 has a plurality of scattering regions 31 in the form of polygons 34.

[0160] These polygons may include, for example, rectangles or lines or straight lines.34 Alternatively or additionally, the polygons or scattering areas may also include barcodes or QR codes or numbers and / or letters.

[0161] The polygons have different dimensions and form a cascaded arrangement with crosshairs.

[0162] Each or some polygons 34 have preferred unique marking protrusions 35.

[0163] according to Figure 5 The marking protrusion 35 in the embodiment includes line markings, wherein the four rectangles 34 have one, two, three, and four line markings respectively.

[0164] This can provide a clear (i.e., one-to-one) (geometric) configurable property for pattern M, so that the image of scattering pattern M has a clearly identifiable orientation in each rotation, shape distortion and mirroring, scaling or translation.

[0165] Figure 6 This diagram illustrates a contour plot K according to one embodiment, which measures the detected scattered radiation 13 (see...). Figure 1 ) and according to Figure 5 The scanner coordinates x, y, z on the scattering pattern element 30 in the embodiment (see [reference]). Figure 3 It is obtained through association.

[0166] For further explanation, evaluation, or analysis, and the predistortion function or calibration function that can be calculated therefrom, please refer to the relevant documentation. Figure 4 Explanation.

[0167] Figure 7 A cross-sectional view of one embodiment of the scattering pattern element holding device 40 according to the present invention is shown.

[0168] Furthermore, the speed and accuracy of the method described above for calculating the predistortion function or calibration function for calibrating the deflection unit are determined, for example, by the achievable contrast (in the contour plot K). The contrast is determined by the (different) surface roughness of the scattering pattern element 30 and, consequently, the backscattering of laser radiation 13 towards photodiodes PD1, PD2, and PD3 (see [reference]). Figure 1 )Decide.

[0169] However, depending on the material of the scattering pattern element, approximately 90% to almost 100% of the laser power is transmitted through the scattering pattern element 30. Tests have shown that about 10% less light is transmitted in the scattering region.

[0170] Therefore, for contrast and thermal management, it is crucial to how to harvest this power and preferably not scatter it back to the photodiode.

[0171] Therefore, according to the present invention, light is absorbed on the inner wall of the cavity 43 of the scattering pattern element holding device 40 after being transmitted through the scattering pattern element 30.

[0172] The scattering pattern element 30 can be disposed on the processing plane 11 by means of the scattering pattern element holding device 40 (see...). Figure 1 Especially for high laser power, such as 50W or 100W or higher, this can significantly improve the contrast of contour plots because (undesirable) backscattering is (largely) avoided or significantly reduced.

[0173] The scattering pattern element holding device 40 has a base surface 41 and a sidewall 42 surrounding the base surface.

[0174] Therefore, the scattering pattern element holding device 40 forms a cavity 43 inside.

[0175] The sidewall 42 is configured at the upper end such that the scattering pattern element 30 can be fixedly supported at the upper end 44.

[0176] The upper end 44 of the sidewall 42 is opposite to an end where the base surface 41 is connected to the sidewall 42.

[0177] For this purpose, the sidewall 42 may have a corresponding chamfer or insertion groove at the upper end 44, and the upper end 44 of the sidewall 42 may be configured as a shoulder.

[0178] It is also conceivable that the sidewall 42 has three or four support protrusions, for example, one support protrusion is provided on one side of the sidewall 42 for placing the scattering pattern element 30.

[0179] The corresponding chamfers, insertion slots, or support protrusions may be recessed (viewed from the upper end 44) ​​if necessary, so that the scattering pattern element 30 can be inserted in such a way that the sidewall 42 stabilizes or fixes the position of the scattering pattern element at the upper end 44 to prevent (undesirable) movement.

[0180] In addition, the scattering pattern element holding device 40 has at least one deflection cone 45 disposed on the base surface 41.

[0181] The at least one deflecting cone 45 is constructed and / or configured to deflect incident light toward the inside 46 of the sidewall 42.

[0182] The inner side 46 of the sidewall 42 is configured to absorb light incident on the inner side 46.

[0183] For this purpose, the sidewall 42 may have an absorbing sheet 47. Alternatively or additionally, other absorbing or diffuse scattering elements may be disposed within the cavity 43.

[0184] The base surface of the deflection cone basically covers the entire base surface 41. Alternatively, the base surface of the deflection cone can also be constructed to be slightly smaller than the base surface 41.

[0185] The height of the deflection cone 45 corresponds to at least half the height of the sidewall 42, preferably at least 80% of the height of the sidewall 42. Thus, the incoming light can be absorbed over a large range of incident angles.

[0186] Figure 8 Showing according to Figure 7 According to an embodiment of the scattering element holding device 40 of the present invention, the scattering element holding device 40 holds the scattering pattern element 30.

[0187] Figure 9 An alternative embodiment of the scattering element holding device 40 is shown.

[0188] The "tip" or apex of the deflection cone 45 points towards the base surface 41. In this embodiment, the deflection cone 45 may have an absorbent sheet 47 or the deflection cone 45 (itself) may form an inner side 46 of a sidewall 42.

[0189] Figure 10 A schematic top view of a scattering pattern holding device 40 according to an embodiment of the present invention is shown.

[0190] The scattering pattern holding device 40 holds the scattering pattern element 30. The scattering pattern element 30 is configured to be transparent to the laser wavelength. Thus, the laser light is not scattered onto the photodiodes PD1, PD2, PD3 (see...). Figure 1 A portion of the scattering pattern element 30 can enter the cavity 43 (below the scattering pattern element 30) and be absorbed there.

[0191] The scattering pattern element 30 is held in the scattering pattern holding device 40 in such a way that the transmitted power is completely absorbed without damaging the scattering pattern holding device 40.

[0192] Furthermore, the scattering pattern element 30 is thermally and mechanically separated from the scattering pattern holding device 40, so that the thermal expansion of the scattering pattern holding device has no effect on the scattering pattern element 30.

[0193] At high laser power, the component will heat up significantly. In order to avoid bending, for example, due to the thermal expansion of the scattering pattern element 30, in another embodiment of the invention, the scattering pattern holding device 40 can be actively cooled, for example, by water cooling.

[0194] The scattering pattern element holding device 40 can be made of, for example, aluminum (anodized) or other materials with good thermal conductivity, so as to dissipate heat and not be damaged by laser power.

[0195] Figure 11 A schematic embodiment of a method for calibration or scanning field correction of a scanning field correction system 200 is shown, the system comprising two laser scanning devices 300, a scattering pattern element 30, and a common processing plane 11.

[0196] The photodiode and window are not shown here. For a detailed description of the corresponding arrangement or features of the scattering pattern element 30, please refer to the preceding embodiments.

[0197] In the method according to this embodiment, a calibration function according to the invention is calculated for each of the two laser scanning devices 300.

[0198] By using a calibration function, the respective scanning fields 120 and 122 of the corresponding laser scanning devices 300 are "corrected" or calibrated according to the distortion.

[0199] However, in the case of multiple laser scanning devices 300, for example due to inaccurate (tilted) mounting of the laser scanning heads, the scanning fields 120, 122 may (additionally) be twisted and / or tilted relative to each other. See also Figure 11 The (tilted) scanning fields 120 and 122 are schematically shown in the top view of the machining plane 11 on the right side of the middle.

[0200] For this reason, the laser scanning equipment 300 must also be calibrated / corrected relative to each other in order to obtain the most accurate calibration possible for the laser scanning system.

[0201] To calibrate this relative error between multiple laser scanning devices 300, two laser scanning devices 300 scan the same overlapping region 121 (the overlapping region 121 of the two scanning fields 120, 122) on the scattering pattern element 30.

[0202] The two obtained contour maps K are then aligned by rotation / tilt, and the laser scanning device 300 is calibrated using the obtained calibration function(s).

[0203] Combined with Figure 11 The method described in the embodiments can also be transferred to multiple laser scanning devices 300 (in any arrangement).

[0204] Figure 12 An embodiment of a plurality (e.g., six) laser scanning devices 300 having a scan field correction system 200 is shown, these laser scanning devices having respective scan fields 120, 122, 124, 126, 128, 130. Similarly, as in conjunction with... Figure 11 The regions 121, 123, 125, 127, and 129 that overlap with adjacent scanning fields 120, 122, 124, 126, 128, and 130 on the scattering pattern element 30 can be scanned.

[0205] The corresponding contour map K is then aligned by rotation / tilt, and the laser scanning device is calibrated using the obtained calibration function(s).

[0206] According to Figure 11 and 12 In one embodiment, a relatively large scattering pattern element 30 is used (compared to the scanning field or processing plane).

[0207] According to Figure 13 In an alternative embodiment, the above method can be used to perform scan field correction on the (large) scan field 120 by repositioning the scattering pattern element 30 on the processing plane 11 (using different positions).

[0208] For the sake of the versatility or advantageous manufacturability (in terms of manufacturing cost and consumption) of the scattering pattern element 30 or the corresponding scattering pattern element holding device, it is advantageous to use the relatively small scattering pattern element 30 (compared to the scanning field or processing plane) for scanning field correction of the (significantly) larger scanning field 120.

[0209] However, in order to measure the distortion of the entire or at least most of the scan field 120, the scan pattern element 30 is repositioned in the scan field 120.

[0210] In this process, the scattering pattern element 30 is first positioned at a first location relative to the scanning field 120 and scanned by means of a laser beam, and the corresponding first calibration function is calculated. Figure 13 (See the image above).

[0211] Subsequently, the scattering pattern element 30 is positioned in a second position relative to the scanning field 120 and scanned using a laser beam, and the corresponding second calibration function is calculated. Figure 13 (See the image below).

[0212] By overlapping measurements (using a laser beam to scan) the same area or the same scattering region 31 of the scattering pattern element 30, calibration functions (first and second calibration functions) determined for a portion of the scanning field 120 can be correlated with each other.

[0213] In order to enable the scanning pattern element 30 to be positioned at multiple locations, the scanning pattern element 30 can preferably be movably supported. For example, the scattering pattern element holding device can be movably supported in the XY plane.

[0214] It should be noted that all the parts described above (especially the details shown in the accompanying drawings) are claimed individually and in any combination as an essential part of this invention.

[0215] List of reference numerals

[0216] 10 deflection devices

[0217] 11 Machining plane

[0218] 12 laser beams

[0219] 13 Scattered Radiation

[0220] 20 windows

[0221] 21. Top of window

[0222] 22 Window bottom

[0223] 23 Window Edges

[0224] 30 scattering pattern elements

[0225] 31 Scattering Region

[0226] 31' Scattering Region Image

[0227] 32 First marked area

[0228] 33 Second Marked Area

[0229] 34 polygons

[0230] 35 mark protrusion

[0231] 40 scattered pattern element holding device

[0232] 41 base plane

[0233] 42 sidewalls

[0234] 43 cavity

[0235] 44 Upper end of the side wall

[0236] 45 deflection cone

[0237] 46 inner side

[0238] 47 Absorbent Sheets

[0239] 120, 122, 124, 126, 128, 130 scan fields

[0240] Overlapping areas of 121, 123, 125, 127, and 129

[0241] 200 scan field correction system

[0242] 300 laser scanning equipment

[0243] K contour map

[0244] M-scattering pattern

[0245] M' scattering pattern image

[0246] PD1, PD2, PD3 photodiodes

[0247] x, y, z scanner coordinates

[0248] Coordinates of the x', y', z' contour plot

Claims

1. A method for performing scan field correction on at least one laser scanning device (300), the method comprising the following steps: - Provide scattering pattern elements (30) on the processing plane (11). The scattering pattern element (30) has at least one scattering region (31), which is disposed in the scattering pattern (M); - Using the laser beam (12) of the at least one laser scanning device (300), at least a portion of the scattering pattern elements (30) on the processing plane (11) is scanned along the scanner coordinates (x, y, z). The laser beam passes through at least one window (20) between the deflection unit (10) and the processing plane (11). - Detect scattered radiation (13), which can be generated by scattering and / or reflection of a laser beam (12) as it sweeps or scans the at least one scattering region (31); - A contour map (K) is created by correlating the detected scattered radiation (13) with the scanner coordinates (x, y, z); - Compare the contour map (K) with a reference image of the scattering pattern (M) and determine the deviation between the contour map (K) and the reference image of the scattering pattern (M); - Calculate the calibration function for calibrating the deflection control unit (10) based on the determined deviation. The contour plot (K) includes a scattering pattern image (M') that corresponds to a distorted display of the scattering pattern (M) of the scattering pattern element (30), such that the contour plot (K) has at least one scattering region image (31') that can be assigned to the at least one scattering region (31) of the scattering pattern element (30).

2. The method according to claim 1, characterized in that, A portion of the scattered radiation (13) is propagated through reflection and / or scattering within the window (20) between the upper side (21) and the lower side (22) of the window (20) toward at least one segment of the window edge (23) of the window (20), so that the scattered radiation (13) is emitted from the window edge (23) of the window (20) and can be detected there.

3. The method according to claim 1 or 2, characterized in that, The detection of scattered radiation (13) is performed on at least one segment of the window edge (23) of the window (20).

4. The method according to claim 1 or 2, characterized in that, The scattered radiation is detected using at least one photodiode.

5. The method according to claim 4, characterized in that, The detection of scattered radiation is performed using at least three photodiodes (PD1, PD2, PD3).

6. The method according to claim 5, characterized in that, The at least three photodiodes (PD1, PD2, PD3) are equidistantly distributed.

7. The method according to claim 1 or 2, characterized in that, The amplitude of the contour plot (K) is substantially proportional to the detected scattered radiation (13).

8. The method according to claim 1 or 2, characterized in that, The at least one scattering region image (31') can be assigned one-to-one to the at least one scattering region (31) of the scattering pattern element (30).

9. The method according to claim 1 or 2, characterized in that, The steps for determining the deviation between the contour map (K) and the scattering pattern (M) include steps for fitting and / or interpolating the contour map (K).

10. The method according to claim 1 or 2, characterized in that, The steps for determining the deviation between the contour map (K) and the scattering pattern (M) include determining contour map reference points for multiple scattering region images (31') of the contour map (K).

11. The method according to claim 10, characterized in that, The steps for determining the deviation between the contour map (K) and the scattering pattern (M) include steps for determining the centroid and / or center point and / or shape distortion of multiple scattering region images (31') of the contour map (K).

12. The method according to claim 1 or 2, characterized in that, The steps for determining the deviation between the contour map (K) and the scattering pattern (M) include steps for determining the deviation and / or shape distortion between the reference points of the contour map and the corresponding reference points of the reference image of the scattering pattern (M).

13. A laser scanning device (300) comprising a deflection unit (10) calibrable for scanning field, the laser scanning device (300) having: - At least one deflection unit (10) configured to scan or scan the processing area (11) along predetermined scanner coordinates (x, y, z) by means of a laser beam (12). A scattering pattern element (30) can be disposed on a processing plane, the scattering pattern element (30) having at least one scattering region (31), the at least one scattering region being disposed in a scattering pattern (M); - At least one window (20) is disposed between the deflection unit (10) and the processing area (11); - At least one photodiode (PD1, PD2, PD3), said at least one photodiode being configured to detect scattered radiation (13), said scattered radiation being generated by scattering and / or reflection of a laser beam as it sweeps across said at least one scattering region (31) of a scattering pattern element (30); - A calculation unit configured to create a contour map (K) by associating the detected scattered radiation (13) with scanner coordinates (x, y, z) and to calculate a calibration function for calibrating and controlling the deflection unit (10) based on the deviation of the contour map (K) from a reference image of the scattering pattern (M). The contour plot (K) includes a scattering pattern image (M') that corresponds to a distorted display of the scattering pattern (M) of the scattering pattern element (30), such that the contour plot (K) has at least one scattering region image (31') that can be assigned to the at least one scattering region (31) of the scattering pattern element (30).

14. The laser scanning device (300) according to claim 13, characterized in that, Two photodiodes are provided, which are disposed on a section of the window edge (23) of the window (20).

15. The laser scanning device (300) according to claim 13 or 14, characterized in that, The at least one photodiode is configured and / or set to detect a portion of the scattered radiation (13) that propagates through a segment of the window edge (23) of the window (20) by reflection and / or scattering between the upper side (21) and the lower side (22) of the window (20).

16. The laser scanning device (300) according to claim 13 or 14, characterized in that, The at least one photodiode (PD1, PD2, PD3) is configured to output a measurement signal to the computing unit, which is substantially proportional to the detected scattered radiation (13).

17. The laser scanning device (300) according to claim 13 or 14, characterized in that, The amplitude of the contour plot (K) is substantially proportional to the detected scattered radiation (13) or to the measurement signal of the at least one photodiode (PD1, PD2, PD3).

18. The laser scanning device (300) according to claim 13 or 14, characterized in that, The scattering pattern element (30) is configured as a plate and has a scattering pattern (M) comprising a plurality of scattering regions (31). The scattering region (31) is constructed as a roughened and / or printed surface area and / or aperture of the scattering pattern element (30) or constructed within the volume of the scattering pattern element (30). The scattering region (31) is configured in the scattering pattern (M) such that an image of the scattering pattern (M) or an image of a portion of the scattering pattern can be clearly identified in each rotation or shape distortion or mirroring or scaling or translation.

19. The laser scanning device (300) according to claim 18, characterized in that, The scattering region (31) includes a first arrangement of a first marked region (32). Each of the first marked regions (32) is surrounded by a plurality of second marked regions (33) arranged in a second manner.

20. The laser scanning device (300) according to claim 19, characterized in that, The scattering region (31) includes a first arrangement of a substantially circular first marked region (32). Each of the first marking regions (32) is surrounded by a plurality of substantially circular second marking regions (33) arranged in a second manner.

21. The laser scanning device (300) according to claim 19 or 20, characterized in that, The second arrangement of the plurality of second marking regions (33) differs from that of at least two of the first marking regions (32) in terms of the angular arrangement and / or number of the second marking regions (33).

22. The laser scanning device (300) according to claim 18, characterized in that, The scattering region (31) comprises multiple polygons (34) having different sizes and / or multiple polygons (34) having marking protrusions (35).

23. A scanning field correction system (200) comprising at least one laser scanning device (300) according to any one of claims 13 to 22 and at least one scattering pattern element (30) for scanning field correction. The scattering pattern element (30) is configured as a plate and has a scattering pattern (M) comprising a plurality of scattering regions (31). The scattering region (31) is constructed as a roughened and / or printed surface area and / or aperture of the scattering pattern element (30) or constructed within the volume of the scattering pattern element (30). The scattering region (31) is configured in the scattering pattern (M) such that an image of the scattering pattern (M) or an image of a portion of the scattering pattern can be clearly identified in each rotation or shape distortion or mirroring or scaling or translation.

24. The scanning field correction system (200) according to claim 23, comprising at least two laser scanning devices (300) whose scanning fields (120, 122, 124, 126, 128) at least partially overlap, wherein the laser scanning devices (300) are calibrated relative to each other by means of a scattering pattern element (30).

Images