Maintenance method and maintenance system for a laser optics system

Abstract

The invention relates to a maintenance method (10) for determining soilings (12) on a laser optics system (14) of a laser beam system (16), having the method steps of: a) producing (20) a speckle image (22) with a plurality of speckles (30) on a speckle image blank (26), wherein the speckle image (22) is formed by irradiating a light-sensitive surface (24) of the speckle image blank (26) with a laser beam (18) passing through the laser optics system (14); b) evaluating (32) the speckle image (22), wherein at least one speckle geometry (34) is determined of at least one of the speckles (30); c) comparing (36) the at least one determined speckle geometry (34) with at least one stored characteristic speckle geometry (38), wherein a soiling (12) of the laser optics system (14) is detected when a predetermined similarity or agreement of the determined speckle geometry (34) with the characteristic speckle geometry (38) is found; g) outputting (40) soiling information (42), wherein the soiling information (42) includes at least the number (43) of detected soilings (12). The invention also relates to a maintenance system (68).

Description

[0001] Maintenance procedure and maintenance system for a laser beam optics

[0002] Background of the invention

[0003] The invention relates to a maintenance method and a maintenance system for detecting contamination on a laser beam optics of a laser beam system.

[0004] Laser beam systems with laser beam optics for forming a laser beam are known from the state of the art and are used, for example, for workpiece processing in production. The laser beam optics comprise several optical components that are used to form the beam profile of the laser beam. To enable high-precision processing with the laser beam and to avoid power losses of the laser beam, stringent cleanliness requirements are placed on the laser beam optics.

[0005] However, the laser beam system, especially during workpiece processing, is typically exposed to airborne contaminants in the form of airborne particles. These particles reach the laser beam optics via the air circulation and contaminate the optical components. This leads to unwanted interference with the laser beam guidance within the laser beam optics, resulting in a loss of laser power and the generation of stray light. This can result in reduced quality during workpiece processing and material waste.

[0006] To prevent the consequences of damage to the laser beam optics, they are usually checked for contamination. A known prior art method involves the creation of so-called spot patterns, in which the laser beam is briefly directed onto a light-sensitive surface. This process involves a so-called burn-off of the light-sensitive surface, with the burn-off residues creating a spot-like pattern depending on the spatially distributed laser radiation.

[0007] The resulting spot images must then be laboriously interpreted by experts to obtain an indication of potential quality-reducing contamination in the laser beam optics of the laser beam system. Furthermore, conventional spot images exhibit a large number of spots, making expert interpretation time-consuming and prone to errors. As a result, contamination can only be detected with a delay and, moreover, with a high degree of uncertainty, thus perpetuating the aforementioned disadvantages.

[0008] DE 10 2018 214 170 A1 discloses a machine learning device for quality assessment of a laser beam intensity distribution. An acrylic block is irradiated with a laser beam to generate a burn pattern of the beam profile. However, the described device is not suitable for detecting individual contaminations in the laser beam optics.

[0009]

[0010] It is an object of the invention to provide a method and a device for reliably and quickly detecting contamination on a laser beam optics.

[0011] This object is achieved according to the invention by a maintenance method according to patent claim 1. Furthermore, the object is achieved according to the invention by a maintenance system according to patent claim 7. The subclaims describe preferred embodiments of the invention.

[0012] According to the invention, a maintenance method is provided.

[0013] The maintenance method is designed to detect contamination on a laser beam optics system of a laser beam system. The maintenance method is designed, in particular, to detect individual contamination on a laser beam optics system.

[0014] The maintenance method is particularly suitable for being performed on a laser processing machine for processing workpieces. The laser beam system preferably comprises a solid-state laser. The laser beam system is particularly preferably designed to generate a laser beam with a wavelength between 1050 nanometers and 1100 nanometers, in particular a wavelength of 1064 nanometers or 1080 nanometers. The inventors have recognized that the maintenance method described above and below is particularly suitable for laser beam systems with the aforementioned specifications.

[0015] According to the invention, contamination can be understood as the localized adhesion of one or more suspended particles, in particular particles, to an optical component of the laser beam optics, which typically causes a local impairment of the laser radiation of the laser beam and can cause thermal damage. For example, in the case of metallic particles, this can lead to local melting of the laser beam optics, causing the particle to be burned into the laser beam optics.

[0016] The maintenance procedure includes at least the following steps:

[0017] A first step a) of the maintenance process involves generating a spot image. The spot image is typically created by irradiating a light-sensitive surface of a spot image blank with the laser beam of the laser beam system. The laser beam passes through the laser beam optics before striking the light-sensitive surface, allowing contaminants that impair the laser beam to be imaged on the light-sensitive surface. In addition to a large number of spots characteristic of the burning process of the light-sensitive surface, characteristic spots are created that are attributable to the impairment of the laser beam by contamination of the laser beam optics.

[0018] The light-sensitive surface of the spot image blank, in particular the entire spot image blank, is preferably designed as photographic paper. This allows for a particularly high resolution when generating the spot image, thereby increasing the accuracy of the maintenance process.

[0019] The spot image is preferably generated under predetermined parameters of the laser beam system. Alternatively, the parameters can be read from a machine control system of the laser beam system during exposure of the light-sensitive surface. In other words, the parameters of the laser beam system are known during the generation of the spot image. In particular, the laser power and / or the distance between the laser beam optics and the light-sensitive surface are known during generation. This allows for a particularly precise evaluation of the spot image.

[0020] A further step b) of the maintenance method involves evaluating the spot pattern. The evaluation comprises determining at least one spot geometry of at least one of the spots generated during the exposure of the light-sensitive surface. Typically, the spot geometries of several, in particular all, spots of the spot pattern are determined. In other words, the spot geometry is determined both by the spots characteristic of the burning process of the light-sensitive surface and by the characteristic spots. The evaluation of the spot pattern can be understood as a separation of the spots of the spot pattern.

[0021] Graphic image analysis algorithms are preferably used to evaluate the stain pattern. In other words, the analysis is preferably performed computer-assisted. This allows for faster analysis and thus the maintenance process. The stain geometries are typically stored in a data storage device for further processing.

[0022] A further method step c) of the maintenance method involves comparing the at least one specific spot geometry with at least one stored characteristic spot geometry. In other words, the previously determined spot geometry is compared with reference geometries, wherein the reference geometries were demonstrably generated by contamination of the laser beam optics. If the comparison reveals that the specific spot geometry has a predetermined similarity or match with the characteristic spot geometry, a contamination underlying the specific spot geometry is identified.

[0023] Preferably, the spot geometry is compared with several, in particular a large number of, stored characteristic spot geometries. Each characteristic spot geometry is understood to represent a possible spot formation due to contamination of the laser beam optics. As the number of stored characteristic spot geometries increases, the probability of detecting contamination from the maintenance process can be increased.

[0024] Computer-aided comparison algorithms are preferably used to compare the spot geometry with the characteristic spot geometry. This allows the comparison and thus the maintenance process to be carried out even faster. The detected contaminants are typically stored in a data storage device for further processing.

[0025] A further method step g) of the maintenance method provides for the output of contamination information. The contamination information is designed to provide information about possible contamination of the laser beam optics. The contamination information includes at least the number of contaminations determined by comparing the spot geometries with the characteristic spot geometries.

[0026] Preferably, the analysis of the stain image, the comparison of the stain geometry with the characteristic stain geometry, and / or the output of the contamination information are carried out automatically. In other words, the maintenance procedure can be performed essentially automatically, thereby achieving a faster process flow and a higher degree of automation.

[0027] In summary, the invention proposes a maintenance method in which a spot image is generated with a laser beam optics to be tested, forming characteristic spots, wherein the characteristic spots are attributable to a laser beam impaired by contamination. The spot image is then analyzed with regard to the characteristic spots, and an underlying contamination is determined. The maintenance method according to the invention thus represents a fast and reliable method for the early detection of contamination in the laser beam optics, thereby overcoming the disadvantages of the prior art. The maintenance method according to the invention enables maintenance, in particular cleaning of the laser beam optics and / or replacing optical components of the laser beam optics, to be carried out in a targeted manner.

[0028] In a preferred embodiment of the maintenance method, a spot position for the at least one spot is determined in method step b). In other words, in addition to the spot geometry, the position of the spot is also determined. Typically, in method step g), the spot position is output as a projected contamination position using the contamination information. The projected contamination position is to be understood as a position within the beam cross-section. In other words, the position of the contamination can be determined in a cross-sectional plane of the laser beam perpendicular to a laser beam propagation direction. This allows for even more targeted maintenance.

[0029] Furthermore, an embodiment of the maintenance method with an additional method step d) is preferred, which provides for determining a degree of contamination. In other words, the degree of impairment of the laser beam optics or the laser beam by the determined contaminants is determined. The degree of contamination can be determined depending on a number of determined contaminants. Alternatively or additionally, the degree of contamination can be determined depending on the at least one projected contamination position. Typically, the determined degree of contamination is output in method step g). The degree of contamination can, for example, lead to a planned maintenance procedure being carried out earlier or later than planned. This increases maintenance flexibility.

[0030] A further preferred development of the maintenance method is one in which the degree of contamination increases with decreasing distance of the projected contamination position from a spot image center and / or with increasing number of detected contaminations. In a preferred embodiment, the maintenance method comprises method step e), which provides for determining a contaminated optical component of the laser beam optics containing the contamination. In other words, the position of the contamination along the laser beam propagation direction can be determined. The contaminated component can be determined by determining a contour sharpness of the spot geometry caused by the contamination. By determining the contour sharpness, a contamination distance between the light-sensitive surface and the contamination can be determined.With knowledge of the design of the laser beam optics, the contamination distance can be traced back to a specific optical component. Typically, the determined contaminated component is output in process step g). This allows maintenance of the laser beam optics to be limited to one optical component, allowing maintenance to be performed even more quickly.

[0031] An optical component can be understood as meaning, for example but not exclusively, an optical lens, in particular a focusing lens, a protective glass, a plane plate and / or a mirror.

[0032] In a preferred embodiment of the maintenance method, method step c) is performed by a self-learning algorithm. Using a self-learning algorithm, the maintenance method can be performed even faster by incorporating a variety of stains, stain geometries, and characteristic stain geometries. This further increases the probability of detecting contaminants.

[0033] The self-learning algorithm is preferably trained using a plurality of spot geometries and / or characteristic spot geometries whose relationships with contamination of the laser beam optics are known. To determine a relationship between a spot geometry and / or characteristic spot geometry and contamination, one or more experts can, for example, manually assign the spot geometry to a contamination or to no contamination. For example, a manual evaluation of spot images can be provided, which are "labeled" accordingly for the purpose of training the self-learning algorithm. The spot images are preferably evaluated by an expert after maintenance has been performed or during maintenance on the laser beam system and automatically sent back to the maintenance system.The evaluated stain images can also be provided to the maintenance system manually by an operator or automatically via a mobile device. Preferably, a large number of evaluated stain images are transmitted via known data transmission to a central data storage device in the maintenance system, which serves as the basis for training the self-learning algorithm.

[0034] The underlying task is also solved by a maintenance system.

[0035] The maintenance system is designed to maintain the laser beam optics of a laser beam system described above and below. The maintenance method is typically designed to detect contamination on the laser beam optics.

[0036] In particular, the maintenance system is designed to carry out the maintenance procedure described above and below.

[0037] The maintenance system has at least one input unit with an imaging device. The input unit is designed to input a stain image. Preferably, the imaging device is designed to digitally input the stain image into the maintenance system. Digital input significantly simplifies further processing of the stain image.

[0038] The imaging device is preferably designed as a camera, in particular a digital camera. The maintenance system also comprises an evaluation unit. The evaluation unit is designed to determine at least one spot geometry from the spot image. The evaluation unit is preferably designed to implement computer-assisted image evaluation algorithms.

[0039] Furthermore, the evaluation unit is configured to determine contamination by comparing the spot geometry with at least one stored characteristic spot geometry. Preferably, the evaluation unit is configured to implement computer-assisted comparison algorithms.

[0040] The maintenance system further comprises at least one output unit. The output unit is designed to generate and output contamination information. The output unit can be designed to output the contamination information graphically, in particular for display on a screen.

[0041] The maintenance system can be designed as a maintenance computer, wherein the maintenance computer comprises the input unit, the evaluation unit and / or the output unit.

[0042] In a preferred embodiment, the maintenance system comprises a mobile device. The mobile device can have the input unit and / or the output unit. This enables the stain image to be transmitted to the evaluation unit, particularly at a large distance. This allows the stain image to be input particularly quickly and easily on-site at the laser beam system.

[0043] In a further preferred embodiment, the maintenance system comprises a mobile terminal. The mobile terminal can have the output unit. This enables the contamination information to be transmitted, particularly at a large distance. This allows maintenance of the laser beam system to be performed at a distance from the evaluation unit.

[0044] Further advantages of the invention will become apparent from the description and the drawings. Likewise, the above-mentioned and further-described features can be used individually or in combination in any desired manner. The embodiments shown and described are not intended to be exhaustive, but rather are exemplary in nature for describing the invention.

[0045] Detailed description of the invention and drawing

[0046] Fig. 1 shows a maintenance method for detecting contamination on a laser beam optics of a laser beam system in a schematic representation.

[0047] Fig. 2 shows a schematic representation of a laser beam system with a laser beam optics and a maintenance system for detecting contamination on the laser beam optics of the laser beam system.

[0048] Fig. 3 shows a spot image in a partially photographic and partially schematic view.

[0049] Fig. 1 shows a schematic representation of a maintenance method 10 according to the invention. The maintenance method 10 is explained below with reference to the other figures of the drawing.

[0050] The maintenance method 10 is designed to detect contamination 12 (see Fig. 2) on a laser beam optics 14 (see Fig. 2) of a laser beam system 16 (see Fig. 2). The contamination 12 typically impairs the beam path of a laser beam 18 (see Fig. 2) of the laser beam system 16, thereby reducing the processing quality of the laser beam system 16.

[0051] The maintenance method 10 comprises at least the following method steps: In a first method step 20, a spot image 22 (see Figs. 2, 3) is generated. The spot image 22 is typically generated by irradiating a light-sensitive surface 24 (see Fig. 2) of a spot image blank 26 (see Fig. 2). In other words, the laser beam 18 passing through the laser beam optics 14 in the laser beam propagation direction 28 (see Fig. 2) is directed onto the spot image blank 26.

[0052] The light-sensitive surface 24, in particular the entire spot image blank 26, is preferably formed from photographic paper. This ensures the creation of a high-quality spot image 22.

[0053] By exposing the light-sensitive surface 24 to the laser beam 18, in particular for a short time, a controlled reaction, in particular a so-called burning, of the light-sensitive surface 24 is typically effected. In other words, the laser beam 18 vaporizes the light-sensitive surface 24. This creates burning residues on the spot image blank 26, which, depending on the locally acting light intensity of the laser beam 18, form high-contrast spots 30 (see Figs. 2, 3). The spot image 22 typically has a plurality of spots 30.

[0054] A further method step 32 involves evaluating the stain image 22. The evaluation includes determining at least one stain geometry 34 (see Fig. 2) of at least one of the stains 30. Preferably, the stain geometry 34 of several, in particular of all, stains 30 is determined, thereby increasing the accuracy of the maintenance method 10.

[0055] When determining the spot geometry 34, preferably contiguous areas with the same contrast and / or brightness are combined into a geometric structure. In other words, the spot image 22 is separated into its spots 30. The determination of the spot geometry 34 can be performed using graphical image analysis algorithms. This can increase the process speed and accuracy.

[0056] A subsequent method step 36 provides for comparing the at least one specific spot geometry 34 with at least one stored characteristic spot geometry 38 (see Fig. 2). Preferably, the specific spot geometry 34 is compared with several, in particular a multiplicity of, stored characteristic spot geometries 38. This makes it possible to locate or detect various contaminants 12. A contaminant 12 on the laser beam optics 14 is typically detected if there is a predetermined similarity and / or agreement between the specific spot geometry 34 and the characteristic spot geometry 38.

[0057] A further method step 40 provides for the output of contamination information 42 (see Fig. 2). The contamination information 42 comprises at least a number 43 (see Fig. 2) of the detected contaminants 12.

[0058] In a particular embodiment of the maintenance method 10, a method step 44 is provided in which a spot position 46 (see Figs. 2, 3) of the at least one spot 30 is determined. The spot position 46 is typically determined in the spot image 22. Preferably, the spot position 46 is determined in a coordinate system 48 (see Fig. 3) of the spot image 22. This allows a particularly quick and simple relationship to a laser beam axis 50 (see Figs. 2, 3) to be established, whereby the contamination 12 can be detected more quickly on the laser beam optics 14. Typically, the spot position 46 is output as a projected contamination position 52 (see Fig. 2) by the contamination information 42. In other words, the contamination position 52 indicates the location of the contamination in a beam cross-section 54 (see Figs. 2, 3) of the laser beam 18. This further simplifies the detection of the contamination 12 on the laser beam optics 14.In a further particular embodiment of the maintenance method 10, an additional method step 56 is provided in which a degree of contamination 58 (see Fig. 2) is determined as a function of the at least one projected contamination position 52 and / or the number 43 of the determined contaminants 12.

[0059] For example, it can be provided that a single detected contamination 12, a small-area spot geometry 34 caused by the contamination 12, and / or a large distance of the contamination position 52 from the laser beam axis 50 leads to a low degree of contamination 58. In other words, the impairment of the laser beam 18 by the contamination 12 can be assessed as low in this case. Maintenance of the laser beam optics 14 can thereby be postponed, for example.

[0060] Furthermore, for example, it can be provided that multiple detected contaminants 12, a large-area spot geometry 34 caused by at least one contaminant 12, and / or a small distance between the contaminant position 52 and the laser beam axis 50 lead to a high degree of contamination 58. In other words, the impairment of the laser beam 18 by the contaminant 12 can be assessed as significant in this case. Maintenance of the laser beam optics 14 can be performed prematurely in this case, for example.

[0061] Typically, the contamination information 42 includes the determined contamination level 58. In other words, the contamination level 58 can be output together with the number 43 of the contaminants 12.

[0062] In a particularly preferred embodiment of the maintenance method 10, the additional method step 60 is provided, in which a contaminated optical component 62 (see Fig. 2) of the laser beam optics 14, which has the contamination 12, is determined. The contaminated component 62 is typically determined by determining a contour sharpness 64 (see Fig. 2) of the spot geometry 34 caused by the contamination. With knowledge of the contour sharpness 64, a contamination distance 66 (see Fig. 2) of the contamination 12 to the light-sensitive surface 24 can be determined, and the contamination 12 can be assigned to an optical component 62 arranged at the contamination distance 66. This makes it possible to narrow down the location of the contamination 12 on the laser beam optics 12 to the contaminated optical component 62, whereby maintenance can be carried out more quickly.

[0063] Preferably, the contaminated optical component 62 and / or the contamination distance 66 is designated and output in the contamination information 42 according to method step 40.

[0064] Particularly preferably, method step 36 is performed by a self-learning algorithm. By comparing the spot geometry 34 with a characteristic spot geometry 38, the maintenance method 10 can be performed particularly quickly and efficiently, including a large number of spots 30 and characteristic spot geometries 38. This can increase the probability of detecting contaminants 12 in the maintenance method 10.

[0065] Fig. 2 shows an embodiment of a maintenance system 68.

[0066] The maintenance system 68 is configured and designed to maintain the laser beam optics 14 of the laser beam system 16. The maintenance system 68 is designed to perform the maintenance method 10 (see Fig. 1).

[0067] The laser beam system 16 is typically a laser processing machine for processing a workpiece (not shown in detail). The laser beam system 16 preferably has a laser beam generator 70 for generating the laser beam 18. The laser beam generator 70 is typically a solid-state laser. The laser beam 18 preferably has a wavelength between 1050 nanometers and 1100 nanometers, particularly preferably a wavelength of 1064 nanometers or 1080 nanometers. The laser beam 18 generated in the laser beam generator 70 is processed within the laser optics 14 as it propagates in the laser beam propagation direction 28 to enable optimal processing of the workpiece. In other words, important process parameters of the laser beam 18, for example, a focus position and / or a beam cross-section 54, can be adjusted using the laser optics 14.

[0068] The laser optics 14 typically comprises a plurality of optical components 62. The optical components 62 can be designed, for example, as an optical lens, in particular as a focusing lens, as a protective glass, as a plane plate, and / or as a mirror. As shown, the laser optics 14 comprises three optical lenses 72, 74, 76. The optical lenses 72, 74, 74 are arranged one behind the other in the laser beam propagation direction 28.

[0069] As shown, the optical lens 76 has a contamination 12. The contamination 12 can impair the laser beam 18 and thus reduce the processing quality of the laser beam system 16.

[0070] To ensure the processing quality of the laser beam system 16, the maintenance method 10 can be carried out using the exemplary maintenance system 68 shown. As shown, a spot image blank 26 can be positioned in the beam path of the laser beam 18 to cause the light-sensitive surface 24 to be exposed by the laser beam 18. In response to the exposure, the spot image 22 is generated. The generated spot image 22 is then further processed by the maintenance system 68.

[0071] The maintenance system 68 comprises at least one input unit 78, wherein the input unit is designed to input a stain image 22. The input unit 78 is preferably designed for digitally reading, in particular scanning and / or graphically imaging, the stain image 22. Typically, the input unit 78 comprises an imaging device 80, in particular a camera, for this purpose. As shown, the input unit 78 is integrally formed in or on a mobile terminal 82. This makes it particularly easy to input the stain image 22. Typically, the light-sensitive surface 24 of the stain image blank 26 is digitally imaged by the imaging device 80. This allows further processing of the stain image 22 to be faster.

[0072] As shown, the spot image 22 can be transmitted from the mobile terminal 82 to a spatially separated maintenance computer 84. The maintenance computer 84 typically has greater computing power than the mobile terminal 82, so that further processing of the spot image 22 can be carried out more quickly upon transmission to the maintenance computer 84.

[0073] The maintenance system 68 also has an evaluation unit 86. As shown, the evaluation unit 86 is integrally formed on the maintenance computer 84.

[0074] The evaluation unit 86 is configured to determine at least one spot geometry 34 from the spot image 22. In other words, the evaluation unit 86 combines at least one contiguous region with the same contrast and / or with the same brightness into a geometric structure. Typically, the evaluation unit 86 determines several, in particular all, spot geometries 34 contained in the spot image 22. In other words, the evaluation unit 86 can be configured to separate the spot image 22 into spot geometries 34. As shown, three exemplary spot geometries 88, 90, 92 are determined by the evaluation unit 86.

[0075] The evaluation unit 86 is also designed to compare the at least one spot geometry 34 with at least one stored characteristic spot geometry 38. In other words, the evaluation unit 86 comprises at least one characteristic spot geometry 38. Typically, the evaluation unit 86 comprises several, in particular a multiplicity of, characteristic spot geometries 38. Each of the characteristic spot geometries 38 is characteristic of a contamination 12. By individually comparing the characteristic spot geometry 38 with the determined spot geometry 34, a contamination can thus be inferred if a predetermined degree of similarity is present. In other words, a contamination 12 can be determined by the formation of the spot geometry 14. The evaluation unit is therefore designed to determine contaminations 12.

[0076] As shown, three exemplary characteristic spot geometries 94, 96, 98 are stored. Further, as shown, an individual comparison, represented by arrows 99, is performed between each characteristic spot geometry 94, 96, 98 and each determined spot geometry 88, 90, 92. For clarity, only two arrows 99 are provided with a reference symbol. The determined spot geometry 90 exhibits a high degree of similarity to the characteristic spot geometry 96. The evaluation unit 86 therefore determines a contaminant 12 as the cause of the formation of the spot geometry 90.

[0077] The maintenance unit 68 further comprises at least one output unit 100. The output unit 100 is configured to generate and output the contamination information 42.

[0078] The output unit 100 is configured to directly and / or indirectly output the contamination information 42. For example, the contamination information 42 can be output directly to the maintenance computer 84. Furthermore, it can be provided that the contamination information 42 is transmitted to the mobile terminal 82 and displayed on a display 104 of the mobile terminal 82. In other words, the mobile terminal 82 can be configured as part of the output unit 100.

[0079] The contamination information 42 comprises at least the number 43 of determined contaminations 12. Preferably, the contamination information 42 also comprises a spot geometry 90 caused by the contamination 12, a projected contamination position 52, a contaminated optical component 62 and / or a contamination distance 66.

[0080] Particularly preferably, the contamination information 42, in particular the contamination position 52, is displayed graphically on the display 104 of the mobile terminal 82. This allows maintenance to be carried out particularly quickly by a maintenance technician (not shown).

[0081] Fig. 3 shows a spot image 22 in a partially photographic view (shown on the right) and in a partially schematic view (shown on the left) for further explanation.

[0082] As a result of the exposure of the light-sensitive surface 24 (see Fig. 2) of the spot image blank 26 (see Fig. 2), an inhomogeneous, so-called burning-off of the light-sensitive surface 24 can be caused within the beam cross-section 54. The inhomogeneous burning-off process leads to the formation of spots 30, which are shown as dark areas in the schematically illustrated view and as bright areas in the photographically illustrated view.

[0083] As shown, the spot pattern 22 comprises a plurality of spots 30, which are typically arranged in a ring around the laser beam axis 50 or a spot pattern center 108. The spots 30 have different spot geometries 34. For reasons of clarity, only three spots 30 and three spot geometries 34 are provided with a reference symbol.

[0084] As shown, the spot image 22 has three characteristic spot geometries 38. The characteristic spot geometries 38 differ from the other spot geometries 34 of the spots 30, in particular by their circular or ring-shaped configuration. The characteristic spot geometries 38 are characteristic of a contamination 12 of the laser beam optics 14 (see Fig. 2). The characteristic spot geometries 38 can be removed by the maintenance procedure

[0085] 10 and the maintenance system 68 are determined, whereby the impurities

[0086] 12, which underlie the respective characteristic spot geometry 38, can be eliminated.

[0087]

[0088] 30

[0089] 10 maintenance procedures; 60 process steps;

[0090] 12 contamination; 62 optical component;

[0091] 14 laser beam optics; 64 contour sharpness;

[0092] 16 laser beam system; 66 contamination distance;

[0093] 18 laser beam; 35 68 maintenance system;

[0094] 20 process steps; 70 laser beam generators;

[0095] 22 spot image; 72 optical lens;

[0096] 24 light-sensitive surface; 74 optical lens;

[0097] 26 spot image blank; 76 optical lens;

[0098] 28 Laser beam propagation direction; 40 78 Input unit;

[0099] 30 spot; 80 imaging device;

[0100] 32 process steps; 82 mobile device;

[0101] 34 spot geometry; 84 maintenance calculator;

[0102] 36 process steps; 86 evaluation units;

[0103] 38 characteristic spot geometry; 45 88 exemplary spot geometry;

[0104] 40 process steps; 90 exemplary spot geometry;

[0105] 42 contamination information; 92 exemplary spot geometry;

[0106] 43 number; 94 exemplary characteristic

[0107] 44 process steps; spot geometry;

[0108] 46 spot position; 50 96 exemplary characteristic

[0109] 48 Coo rd in ate n sy ste m ; spot geometry;

[0110] 50 laser beam axis; 98 exemplary characteristic

[0111] 52 projected spot geometry;

[0112] Contamination position; 99 arrow;

[0113] 54 Beam cross-section; 55 100 Output unit;

[0114] 56 process steps; 104 display;

[0115] 58 contamination level; 108 stain center.

Claims

Patent claims 1. Maintenance method (10) for determining contamination (12) on a laser beam optics (14) of a laser beam system (16), comprising the method steps: a) generating (20) a spot image (22) with a plurality of spots (30) on a spot image blank (26), wherein the spot image (22) is formed by irradiating a light-sensitive surface (24) of the spot image blank (26) with a laser beam (18) passing through the laser beam optics (14); b) evaluating (32) the spot image (22), wherein at least one spot geometry (34) of at least one of the spots (30) is determined; c) comparing (36) the at least one specific spot geometry (34) with at least one stored characteristic spot geometry (38), wherein a contamination (12) of the laser beam optics (14) is determined at a predetermined similarity or match of the specific spot geometry (34) with the characteristic spot geometry (38);g) outputting (40) contamination information (42), wherein the contamination information (42) comprises at least the number (43) of the determined contaminations (12); 2. Maintenance method (10) according to claim 1, wherein in method step b) a spot position (46) for the at least one spot (30) is determined; wherein in method step g) the spot position (46) is output as a projected contamination position (52) by the contamination information (42).

3. Maintenance method (10) according to claim 1 or 2, additionally comprising the method step: d) determining (44) a degree of contamination (58) as a function of the at least one projected contamination position (52) and / or the number (43) of the determined contaminants (12); wherein the degree of contamination (58) is output in process step g).

4. Maintenance method (10) according to claim 3, wherein the degree of contamination (58) increases with decreasing distance of the projected contamination position (52) from a spot image center (108) and / or with increasing number (43) of the determined contaminants (12).

5. Maintenance method (10) according to one of the preceding claims, additionally comprising the method step: e) determining (56) a contaminated optical component (62) of the laser beam optics (14) having the contamination (12) by determining a contour sharpness (64) of the spot geometry (34) caused by the contamination (12); wherein the determined contaminated component (62) is output in method step g).

6. Maintenance method (10) according to one of the preceding claims, wherein method step c) is carried out by a self-learning algorithm.

7. Maintenance system (68) for a laser beam optics (14) of a laser beam system (16) for determining contamination (12) on the laser beam optics (14), in particular for carrying out the maintenance method (10) according to one of the preceding claims, comprising a) at least one input unit (78) with an imaging device (80), in particular a camera, designed to input a spot image (22) into the maintenance system (68); b) an evaluation unit (86) designed to determine at least one spot geometry (34) from the spot image (22) and to determine a contamination (12) by comparing the spot geometry (34) with at least one stored characteristic spot geometry (38); c) at least one output unit (100) designed to generate and output contamination information (42).

8. Maintenance system (68) according to claim 7, comprising a mobile terminal (82), wherein the mobile terminal (82) comprises the input unit (78).

9. Maintenance system (68) according to claim 7 or 8, comprising a mobile Terminal (82), wherein the mobile terminal (82) has the output unit (100).

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