Method for operating a polygon scanner device, laser processing device and laser application device

Abstract

Method for operating a polygon scanner device (14), wherein the polygon scanner device (14) has a plurality of mirror segments (20) arranged next to one another.

Description

[0001] The invention relates to a method for operating a polygon scanner device, a laser processing device and a laser application device.

[0002] Laser processing devices are often used to process workpieces using laser radiation. To deflect the laser radiation, for example, to guide the laser radiation over the workpiece, these laser processing devices typically have a polygon scanner device.

[0003] The object of the invention is to provide a method for operating a polygon scanner device that, in particular, enables high utilization of the polygon scanner device. Furthermore, the object of the present invention is to provide a laser processing device configured to carry out the method. Furthermore, the object of the present invention is to provide a laser application device.

[0004] The invention solves this problem by providing a method having the features of claim 1, a laser processing device having the features of claim 18 and a laser application device having the features of claim 19. Advantageous further developments and / or embodiments of the invention are described in the dependent claims.

[0005] A method according to the invention is suitable for operating a polygon scanner device. The polygon scanner device has a plurality, in particular 4, 6, 8, or 10, of mirror segments arranged side by side.The method comprises the steps of: a) rotating the mirror segments of the polygon scanner device about a rotation axis; b) alternately exposing a first beam path to laser radiation and alternately exposing a second beam path, which is different from the first beam path, to laser radiation while the mirror segments rotate, such that laser radiation via the first beam path and laser radiation via the second beam path impinge on the polygon scanner device simultaneously; and c) deflecting the laser radiation of the first beam path by reflecting the laser radiation of the first beam path by means of the mirror segments of the polygon scanner device, and deflecting the laser radiation of the second beam path by reflecting the laser radiation of the second beam path by means of the mirror segments of the polygon scanner device.

[0006] Advantageously, the simultaneous impingement of the laser radiation from the first beam path and the laser radiation from the second beam path allows the polygon scanner device to achieve particularly high utilization. This allows a workpiece to be processed simultaneously with laser radiation from the first beam path and with laser radiation from the second beam path, thereby reducing the workpiece's processing time.

[0007] The laser radiation of the first beam path and / or the laser radiation of the second beam path may be suitable for processing and / or measuring a workpiece.

[0008] The laser radiation of the first beam path and / or the laser radiation of the second beam path can be pulsed or modulated laser radiation.

[0009] If the polygon scanner device has eight mirror segments arranged side by side, a cross-section perpendicular to the axis of rotation of the mirror segments arranged side by side can have the shape of a regular octagon.

[0010] Each mirror segment can be designed to reflect the laser radiation. All mirror segments can be designed identically. In other words, the mirror segments can be structurally identical.

[0011] The point of impact of the laser radiation of the first beam path on the polygon scanner device and the point of impact of the laser radiation of the second beam path on the polygon scanner device can differ from each other. The laser radiation of the first beam path and the laser radiation of the second beam path can impact the polygon scanner device with a spatial offset.

[0012] The first beam path and the second beam path can each extend from a laser beam source for generating the laser radiation to the polygon scanner device. Each beam path can also be referred to as an input beam path. The method can comprise the step: e) generating the laser radiation using the laser beam source. The laser beam source can have a number of resonators and / or amplifier chains for generating the laser radiation, with each resonator or amplifier chain being assigned to a beam path. This allows the laser beam source to apply laser radiation to each beam path independently of the other beam paths.

[0013] By applying laser radiation to the first beam path, the laser radiation can propagate along the first beam path. By applying laser radiation to the second beam path, the laser radiation can propagate along the second beam path.

[0014] The application of laser radiation to the first beam path and / or the application of laser radiation to the second beam path in step b) can be carried out by means of an electro-optical switching element, an acousto-optical switching element and / or coherent beam superposition.

[0015] A rotational speed Rf and a number of mirror segments n arranged side by side in the circumferential direction can result in a line frequency Zf=RF*n or a scan period T=1 / Zf. The line frequency can be referred to as the scan frequency. The alternating exposure of the first beam path with laser radiation and / or the alternating exposure of the second beam path with laser radiation can each occur at the scan frequency. The resulting exposure frequency is proportional to the number of beam paths provided.

[0016] The alternating exposure of the first beam path and the second beam path to laser radiation in step b) can be carried out such that the laser radiation from the first beam path and the laser radiation from the second beam path impinge on the polygon scanner device simultaneously for a period of time. Either the laser radiation from the first beam path or the laser radiation from the second beam path can impinge on the polygon scanner device before or after the period of time.

[0017] During the execution of step b), laser radiation can impinge on the polygon scanner device without interruption. In other words, the alternating exposure of the first beam path and the second beam path with laser radiation in step b) can be carried out in such a way that at no time does laser radiation not impinge on the polygon scanner device. In other words, laser radiation can impinge on the polygon scanner device continuously and be made available for use.

[0018] The point of impact of the laser radiation from the first beam path on a workpiece to be processed and the point of impact of the laser radiation from the second beam path on the workpiece can differ from each other. The laser radiation from the first beam path and the laser radiation from the second beam path can impact the workpiece with a spatial offset.

[0019] If the beam paths are exposed to pulsed or modulated laser radiation, the individual pulses of the pulsed laser radiation can be disregarded when assessing whether the laser radiation from the beam paths strikes the polygon scanner device simultaneously. In particular, the individual pulses of the pulsed laser radiation can define an envelope of the pulses. The envelope can envelop the pulses. The assessment of whether the laser radiation from the beam paths strikes the polygon scanner device simultaneously in the case of pulsed laser radiation can be made based on the envelope. In other words, whether the laser radiation from the beam paths strikes the polygon scanner device simultaneously in the case of pulsed laser radiation can be determined by examining the envelope instead of individual pulses.Simultaneity in this sense can also occur if there are multiple changes between different beam paths within a scan period, resulting in overlapping envelopes, but the modulation is carried out in such a way that the beam paths are acted upon with a time delay.

[0020] Step c) and step a) can be performed simultaneously.

[0021] The names of individual steps, such as a), b), and c), can only serve to distinguish the individual steps from one another. The names of the individual steps can neither be used to interpret nor to establish a sequence. The names of the steps can aim to present the procedure clearly without establishing a chronological sequence or hierarchy between the steps. The names of the steps can only serve as an aid to better understand and trace the individual steps.

[0022] The polygon scanner device can be designed as a double polygon scanner. The double polygon scanner can have a plurality, in particular 4, 6, 8, or 10, of additional mirror segments arranged next to one another, wherein the additional mirror segments are arranged such that laser radiation is directed from the mirror segments onto the additional mirror segments.

[0023] A further aspect of the invention may be that the method enables highly dynamic scanning beam movement with high utilization and great flexibility in the selection of application zones within an addressable scan length. This great flexibility can relate to the length of an application zone, the location of an application zone, and / or the division into application segments, which can be achieved without modifications or significant losses in utilization. The high utilization can enable increased availability of output beams usable for the application and / or the laser output beam(s) provided by at least one laser source.

[0024] In a further development of the method, the alternating exposure of the first beam path and the alternating exposure of the second beam path in step b) occurs such that laser radiation impinges on a mirror segment of the polygon scanner device via the first beam path, and simultaneously, laser radiation impinges on a mirror segment of the polygon scanner device via the second beam path adjacent to the mirror segment exposed to the laser radiation of the first beam path. This advantageously allows a larger scanning area to be achieved on a workpiece to be machined. For example, a scanning area of ​​the laser radiation of the first beam path can be arranged on the workpiece next to a scanning area of ​​the laser radiation of the second beam path.

[0025] In a further development of the method, the alternating exposure of the first beam path and the alternating exposure of the second beam path in step b) occurs such that laser radiation via the first beam path strikes a mirror segment of the polygon scanner device, and laser radiation via the second beam path simultaneously strikes the mirror segment of the polygon scanner device exposed to the laser radiation from the first beam path. This advantageously allows a reduction in the processing time of a workpiece. A scanning area of ​​the laser radiation of the first beam path on the workpiece can at least partially spatially overlap with a scanning area of ​​the laser radiation of the second beam path on the workpiece.

[0026] In order to achieve a high utilization, the alternating application of the first beam path and the alternating application of the second beam path in step b) can be carried out in such a way that laser radiation alternately strikes adjacent mirror segments via both beam paths simultaneously and laser radiation strikes the same mirror segment via both beam paths simultaneously.

[0027] In a further development of the method, the laser radiation of the first beam path and / or the laser radiation of the second beam path strikes the mirror segments at an angle orthogonal to the axis of rotation.

[0028] In a further development of the method, the angular components of the first beam path directed towards the polygon scanner device and the second beam path directed towards the polygon scanner device have a difference in a plane perpendicular to the axis of rotation with respect to the amount with an amount in a range from 0° to 360° / n, preferably from 0° to 360° / (3*n) or from 0° to 2*360° / (3*n), where n is a number of mirror segments.

[0029] In a further development of the method, the first beam path and the second beam path have an angle between them with an amount in a range from 0° to 360° / n, preferably from 0° to 360° / (3*n) or from 0° to 2*360° / (3*n), where n is a number of mirror segments.

[0030] In a further development of the method, the first beam path has an angle between itself and a plane perpendicular to the axis of rotation, with an amount in a range from 0° to 30°, preferably from 3° to 10°. Additionally or alternatively, the second beam path has an angle between itself and a plane perpendicular to the axis of rotation, with an amount in a range from 0° to 30°, preferably from 3° to 10°. The angle between the first beam path and the plane perpendicular to the axis of rotation and the angle between the second beam path and the plane perpendicular to the axis of rotation can be the same or different from one another.

[0031] In a further development of the method, an extension of the first beam path, which extends from the laser beam source for generating the laser radiation to the polygon scanner device, in the propagation direction of the laser radiation, and an extension of the second beam path, which extends from the laser beam source for generating the laser radiation to the polygon scanner device, in the propagation direction of the laser radiation, form an intersection point when projected onto a plane orthogonal to the rotation axis. The distance between the rotation axis and the intersection point is smaller than the distances between the rotation axis and the mirror segments.

[0032] In a further development of the method, the alternating exposure in step b) is carried out in such a way that no laser radiation impinges on a transition between two adjacent mirror segments of the polygon scanner device. This prevents the transition between two adjacent mirror segments from being illuminated with laser radiation, thus preventing uncontrolled reflection of laser radiation.

[0033] In a further development of the method, the method comprises the step before step b): d) determining a rotational position of the mirror segments. The alternating application of radiation to the first beam path and the alternating application of radiation to the second beam path in step b) takes place as a function of the determined rotational position of the mirror segments and, in particular, taking into account the transitions between adjacent mirror segments. Advantageously, this makes it particularly easy to avoid illuminating the transitions between adjacent mirror segments with laser radiation and / or to achieve switching at a predetermined deflection. Determining the rotational position of the mirror segments can comprise a pre-calculation of the rotational position. The determined rotational position of the mirror segments can be a rotational position which the mirror segments have at the time the laser radiation strikes the mirror segments.

[0034] In a further development of the method, step b) comprises alternately applying laser radiation to a third beam path, which is different from the first beam path and the second beam path, such that laser radiation via the third beam path and laser radiation via the first or second beam path impinge on the polygon scanner device simultaneously. Step c) comprises deflecting the laser radiation of the third beam path by reflecting the laser radiation of the third beam path using the mirror segments of the polygon scanner device. The previously described features for the first beam path and / or the second beam path can apply accordingly to the third beam path.

[0035] In a further development of the method, step b) comprises an alternating application of more than two beam paths.

[0036] In a further development of the method, the alternating loading in step b) takes place several times in a scanning period.

[0037] In a further development of the method, the alternating application in step b) is carried out such that a scanning area is less than 80%, preferably 50%, of a maximum scanning area limited by the plurality of mirror segments and / or the beam conditioning device. If the power provided by the beam source can be used over time, more than 80% can be achieved.

[0038] In a further development of the method, the alternating application in step b) is carried out by distributing the laser radiation between the first beam path and the second beam path by means of coherent coupling. The alternating application in step b) can be carried out by distributing the laser radiation between the first beam path and the second beam path using a beam source for generating the laser radiation by means of coherent coupling.

[0039] In a further development of the method, the laser radiation of the first beam path impinges on the polygon scanner device at a first angle of incidence, and the laser radiation of the second beam path (30) impinges on the polygon scanner device at a second angle of incidence. The method comprises the step: f) changing the first angle of incidence and / or the second angle of incidence by changing the first beam path and / or the second beam path. Step f) and step b) can be performed simultaneously or sequentially.

[0040] In a further development of the method, the change in step f) is carried out based on a measurement of a distance between the laser radiation of the first beam path and the laser radiation of the second beam path on a workpiece.

[0041] In a further development of the method, a combined effect is achieved by applying power to two beam paths on the workpiece in close succession, in that the effect occurs over a period of time that exceeds the period when only one beam path is applied by at least a factor of two.

[0042] A laser processing device according to the invention comprises a polygon scanner device having a plurality of mirror segments arranged side by side. The laser processing device is designed to carry out a method described above.

[0043] A laser application device according to the invention has a rotating multi-segment mirror and several different feed beam paths directed toward the multi-segment mirror. Reflection from the rotating mirror segments results in deflection beam paths. The device enables laser power to be supplied to an application area simultaneously from several deflection beam paths via a beam conditioning device. Alternating modulation of the power application to individual feed beam paths allows for spatially controlled power application within the application area. The alternating modulation supports both simultaneous and alternating power application to different beam paths.

[0044] Preferably, the method according to the invention and / or the laser processing device according to the invention can have at least one of the following aspects: First aspect: Two input beam paths can be selected such that, when projected onto a plane perpendicular to the axis of rotation, they have an angular offset from the input-side center axis in opposite directions, wherein the amount of the angular offset lies in the range between 0° and 360° / n, preferably between 360° / (3*n) and 2*360° / (3*n), where n is the number of mirror segments in the circumferential direction. This opposite angular alignment allows for greater flexibility in the design of the scan fields in terms of position and overlap. With a small angular offset, closely spaced output beams with a combined effect can be enabled. In particular, an increased exposure time even at high scanning speeds and / or greater precision can be achieved if the alignment of the workpiece to the output beams increases over time.With an angular offset of 360° / (2*n), the two output beams can be used consecutively, each with 50% of a scan period of the single beam, in completely overlapping scan fields.

[0045] Second aspect: The angular offset of two input beam paths in the projection plane perpendicular to the rotation axis in opposite directions can have a deviation of less than 20%, preferably 10%, for a similar amount. Symmetry allows for high flexibility in the use of the scan fields in terms of position and overlap.

[0046] Third aspect: Switching between input beam paths can be achieved with an achievable input frequency of at least twice the line frequency (IF = n*RF) and a switching time of max. 10% of the scan period (T = 1 / IF) for line frequencies > 10 kHz, especially > 50 kHz, where RF is the rotational speed. Each sub-beam can be switchable at least at the line frequency. The high switching frequency can enable switching between different beams at least within one scan period. The short switching time allows for high utilization.

[0047] Fourth aspect: Switching and / or switched and / or modulated redistribution between input beam paths using switching concepts can enable flexible control and synchronization with application requirements. In particular, switching can be achieved with the rotation of the multifaceted deflection mirror, preferably based on electro-optical or acousto-optical switching elements and / or coherent beam superposition. This advantageously allows for free triggerability.

[0048] Fifth aspect: If more than two beam paths are alternately exposed to laser radiation, switching between two beam paths can be synchronized with the rotational position of the multifacet deflection mirror by processing a real-time encoder signal of the polygon position and taking into account all transitions between adjacent mirror surfaces in the direction of rotation. The multifacet deflection mirror can be referred to as a polygon scanner device. This allows not only a single scanning period but also a complete rotation to be considered, for example, to compensate for deviations between the individual facets or to be used specifically. For example, errors in facet alignment can be compensated for by adjusting the angle of the input beam paths to a specific facet, especially in directions outside the plane spanned by the direction of rotation.By shifting the switching times, the start and end of processing can be controlled. In the case of two input beam paths, alternating power application can be used, even at 50% and 100% capacity utilization, to shift the scanning area on the workpiece, particularly within limits. With more than two input beam paths, a correspondingly high utilization can result with even lower utilization of the individual beam paths. This can be implemented particularly efficiently on small and widely shiftable scan fields.

[0049] Sixth aspect: Switching between input beam paths can occur multiple times within a scan period. This can, for example, allow for high utilization and efficiency in applications segmented in the scan direction.

[0050] Seventh aspect: The axes of the input beam paths can be actively adjustable with respect to the angle and / or position relative to the multifacet deflection mirror with respect to the components in the plane perpendicular to the rotation plane and / or also deviating components, preferably using galvanometer deflection mirrors, acousto-optical deflectors, and / or coherent beam deflection according to the phased array concept. Active adjustment can be advantageous, for example, to compensate for misalignments of individual facets. Active adjustment can be advantageous to select between output beams in close succession with combined effect and / or widely spaced decoupled effect. Active adjustment can be advantageous to shift the scan areas in addition to timing. Active adjustment can be advantageous to enable an offset of individual scans from one another perpendicular to the scan direction.

[0051] Eighth aspect: A beam path can be aligned during operation by rotating the multifacet deflection mirror. This can be used to reposition the beam without applying power and, if necessary, to optionally accelerate it further, so that a suitable deflection is achieved when power is applied. However, dynamic alignment can also be performed while power is applied, in order to superimpose an additional movement on the scanning movement. For example, the scanning movement can be fully or partially compensated during power application. In this case, the beam path is typically repositioned and a compensation speed is applied while the beam path is not being applied, so that the target position is possible while compensating for the scanning speed when power is applied.This enables a multitude of point-shaped applications with one beam path within a scan period, such as for perforating a layer or film. Such an application, which is intermittent within a scan period, can take place with pulsed or modulated operation of the beam source, but is particularly advantageous in conjunction with the sixth aspect, wherein one beam path is used alternately while the other beam path is repositioned. The active adjustment can be advantageous for implementing a superimposed movement during a scan, such as temporarily compensating for the scanning movement induced by rotation. For example, a perforation in which the beam must be held in one position for a processing duration can otherwise be switched off. Repositioning and adjustment of the target speed can take place during the pauses.This can be particularly advantageous in conjunction with the sixth aspect, where one beam is used alternately while the other beam is repositioned.

[0052] Ninth aspect: At least three input beam paths can be provided, each with controllable power input. The additional beams allow for increased flexibility, particularly in increasing the number of scanned application beams per scan period. Each beam path exposed to laser radiation can be referred to as an application beam.

[0053] Tenth aspect: At least three input beam paths with angular components of the axes in the plane spanned perpendicular to the rotation axis relative to the input central axis can be provided in an angular range of ± 2*360° / (3*n). The extensions of the two input beam paths with the greatest difference in the angular components, when projected onto a plane orthogonal to the rotation axis, can have an intersection point that is a smaller distance from the rotation axis than the mirror segments. The angular components preferably differ by no more than 10% from the input central axis with different signs. Further input beam paths preferably have different angular components such that the angular range is divided into segments of similar angular segments and / or that further input beam paths have a difference in the plane directed out of the plane.Such differences in the alignment to the plane spanned by the rotation axis make it possible to apply further partial beams without disadvantageously reducing the angular differences of the input beams.

[0054] Eleventh aspect: multiple application beams can be used simultaneously in different ways. In connection with the seventh aspect, this can be particularly advantageous with reduced and thus movable scan areas of the individual application beams if they are alternately supplied with power. Alternatively or additionally, instead of a correspondingly shortened scan time per application beam, multiple output beams can also be used simultaneously over a larger scan area. This can be particularly advantageous with more than two input beam paths. For example, in the case of three beam paths at the facet transition, only one input beam path can be switched off at a time, while the other two can pass through, thus increasing the scan time per beam from 33% to 66%. The scan field can accordingly be enlarged from 33% to 66% (of the ideal scan field).This can be particularly efficient if individual lasers are not used for each input beam path, but the total available power is distributed over the individual input beam paths in a time-variable manner.

[0055] Twelfth aspect: Pulsed or modulated / modulatable laser radiation can be used in a pulse-synchronized manner such that the time window for switching between the input beam paths, determined by application requirements and rotation, occurs when no or only low laser power is present. When using beam sources with limited triggerability, the switching edges are adjusted accordingly. Especially when using ultrashort-pulsed beam sources, switching is preferably synchronized with the seed frequency. Many laser systems can offer a high degree of flexibility, so it may be sufficient to trigger the laser accordingly, possibly even shifting the pulses slightly, so that synchronization is derived from application requirements and rotation.Ultrashort pulse lasers, in particular, can offer systems with a fixed repetition frequency, making it advantageous to synchronize the rotation, application, and laser for improved performance. Other ultrashort pulse lasers can offer the option of selecting and amplifying individual pulses from the seed source using pulse pickers, advantageously synchronizing the switching processes with the seed pulses to minimize jitter.

[0056] Thirteenth aspect: Supplied input beam paths can have a supporting beam shaping feature, in particular an angular spectrum, that allows an application with multi-spot profiles and / or with adapted intensity profiles, in particular with so-called flat-top profiles, to be carried out via this input beam path. This can enable processing with parallel, offset scan tracks from an input beam path and / or more efficient / quality-enhanced processing through beam shaping.

[0057] Fourteenth aspect: Angular offset between input beam paths can be provided with an additional angular component to that in the plane perpendicular to the rotation axis. This can enable processing with parallel offset scan tracks from different input beam paths in one scan period.

[0058] Fifteenth aspect: Relative motion between the fixture and the workpiece with components perpendicular to the scanning direction can be provided. This can increase throughput or R2R capability.

[0059] Further advantages and advantageous embodiments of the invention can be found in the figures, their description, and the claims. All features disclosed in the figures, their description, and the claims can be essential to the invention both individually and in any combination. They show: Fig. 1 a schematic representation of a laser processing device with a polygon scanner device, Fig. 2 to 5 each show a schematic representation of the polygon scanner device of Fig. 1 during a rotation of mirror segments of the polygon scanner device, Fig. 6 a schematic representation of trajectories along which laser radiation of the laser processing device of Fig. 1 is guided by deflection using the polygon scanner device, Fig. 7a) to 7d) Graphs of amplitudes versus a rotation angle of the polygon scanner device for the trajectories of Fig. 6, Fig. 8 a schematic representation of further trajectories for a variant of the application of beam paths of the laser processing device of Fig. 1, Fig. 9a) to 9e) Graphs of amplitudes versus a rotation angle of the polygon scanner device for the trajectories of Fig. 8, and Fig. 10 a schematic flow of a method for operating the polygon scanner device of Fig. 1.

[0060] Fig. 1 shows a laser processing device 10. The laser processing device 10 has a laser beam source 12, a polygon scanner device 14, and a beam conditioning device 16.

[0061] The laser beam source 12 is configured to generate laser radiation 18. The laser radiation 18 of the laser beam source 12 propagates along a first beam path 28, a second beam path 30, and a third beam path 32. The first beam path 28, the second beam path 30, and the third beam path 32 differ from one another.

[0062] The laser radiation 18 of the first beam path 28, the laser radiation 18 of the second beam path 30 and the laser radiation 18 of the third beam path 32 are each suitable for processing a workpiece.

[0063] The laser beam source 12 has three Fig. 1, optical switches (not shown) with which the first beam path 28, the second beam path 30, and the third beam path 32 can be independently exposed to laser radiation 18. Each optical switch can be designed as an acousto-optical modulator.

[0064] Instead of the three optical switches, the beam source offers an alternative way of distributing the laser power across the three beam paths, whereby, in particular, two beam paths can be supplied with power simultaneously. This distribution can be achieved, for example, using an acousto-optical deflector, a sequential arrangement of several acousto-optical modulators with the diffracted beam portion applied to the beam paths, or even via coherent coupling.

[0065] The laser radiation 18 strikes the polygon scanner device 14. The polygon scanner device 14 has a plurality of adjacently arranged mirror segments 20. In the illustrated initial example, the polygon scanner device 14 has eight adjacently arranged mirror segments 20. A cross-section of the adjacently arranged mirror segments 20 has the shape of a regular octagon. Each mirror segment 20 is designed to reflect the laser radiation 18.

[0066] The mirror segments 20 rotate about a rotational axis. Due to the rotation of the mirror segments 20, the laser radiation is deflected by reflection depending on the rotational position of the mirror segments 20. The laser radiation 18 strikes the rotating mirror segments 20 in such a way that the reflected laser radiation 18 undergoes an angular deflection. Fig. 1 shows the maximum angular deflection 22.

[0067] The reflected laser radiation 18 strikes the beam conditioning device 16 in the form of an F-Theta lens. Fig. Figure 1 shows an example of a telecentric arrangement of the F-theta lens 16. The beam conditioning device 16 converts the angular deflection of the reflected laser radiation 18 into a translation. As a result, the laser radiation 18 is guided over a workpiece 24 by the rotation of the mirror segments 20, with the laser radiation 18 impinging on the workpiece 24 at a constant angle of incidence. Based on the maximum angular deflection 22, a maximum width 26 of a scanning area on the workpiece 24 results.

[0068] While the laser radiation 18 is guided over the workpiece 24, the workpiece 24 can be moved in a feed direction. This allows the laser radiation 18 to be guided over a region of the workpiece 24. In other words, the laser radiation can be directed over an area that is larger than the scanning area.

[0069] Fig. 2 to 5 each show a schematic representation of the polygon scanner device 14 in different rotational positions.

[0070] Fig. 2 shows that the first beam path 28 is exposed to laser radiation 18. The second beam path 30 is not exposed to laser radiation 18. The third beam path 32 is exposed to laser radiation 18.

[0071] The first beam path 28, the second beam path 30, and the third beam path 32 each extend from the laser beam source 12 to the mirror segments 20. The first beam path 28, the second beam path 30, and the third beam path 32 do not change direction while the mirror segments 20 rotate. An imaginary extension of the first beam path 28, the second beam path 30, and the third beam path 32 in the propagation direction of the laser radiation 18 can intersect at an intersection point 34. A distance 36 between the rotation axis 38 and the intersection point 34 is smaller than distances 40 between the rotation axis 38 and the mirror segments 20.

[0072] A point of incidence 42 of the laser radiation 18 of the first beam path 28 on the mirror segments 20 and a point of incidence 44 of the laser radiation 18 of the third beam path 32 on the mirror segments 20 differ from one another. In other words, the laser radiation 18 of the first beam path 28 and the laser radiation 18 of the third beam path 32 impinge on the polygon scanner device 14 with a spatial offset.

[0073] The laser radiation 18 of the first beam path 28 strikes a mirror segment 20 and at the same time laser radiation 18 of the third beam path 32 strikes a mirror segment 20 adjacent to the mirror segment 20 exposed to the laser radiation 18 of the first beam path 28.

[0074] The second beam path 30 is in the Fig. 2, the polygon scanner device 14 is not exposed to laser radiation 18. This prevents a transition 46 from occurring between the two adjacent mirror segments 20 exposed to laser radiation 18 of the first beam path 28 and laser radiation 18 of the third beam path 32.

[0075] Fig. 3 shows another rotational position of the polygon scanner device 14. Fig. 3 shows that the first beam path 28 is exposed to laser radiation 18. The second beam path 30 is exposed to laser radiation 18. At this rotational position, the exposure to laser radiation 18 for the third beam path 32 ends. This prevents laser radiation 18 of the third beam path 32 from striking a transition 46 between two mirror segments 20 upon further rotation.

[0076] The laser radiation 18 of the first beam path 28 strikes a mirror segment 20 and at the same time laser radiation 18 of the second beam path 30 strikes the same mirror segment 20.

[0077] Fig. 4 shows another rotational position of the polygon scanner device 14. Fig. 4 shows that in this rotational position, the application of laser power 18 ends at beam path 28. This prevents laser radiation 18 of the first beam path 28 from hitting a transition 46 between two mirror segments 20. In this rotational position, which is different from the Fig. 3 temporally subsequent rotational position, the third beam path 32 is again subjected to power 18 and beam path 30 continues to be subjected to power 18.

[0078] The laser radiation 18 of the second beam path 30 strikes a mirror segment 20 and at the same time laser radiation 18 of the third beam path 32 strikes the same mirror segment 20.

[0079] Fig. 5 shows another rotational position of the polygon scanner device 14. Fig. 5 shows that the first beam path 28 is exposed to laser radiation 18. For the second beam path 30, the exposure to laser power 18 ends. The third beam path 32 is exposed to laser radiation 18. This prevents laser radiation 18 of the second beam path 30 from impinging on a transition 46 between two mirror segments 20.

[0080] The laser radiation 18 of the first beam path 28 strikes a mirror segment 20 and at the same time laser radiation 18 of the third beam path 32 strikes a mirror segment 20 adjacent to the mirror segment 20 exposed to the laser radiation 18 of the first beam path 28.

[0081] Due to the continuous rotating mirror segments 20 around the rotation axis 38, the Fig. 2 to 5. This results in alternating exposure of the first beam path 28, the second beam path 30, and the third beam path 32 with laser radiation 18 while the mirror segments 20 rotate, so that laser radiation 18 impinges on the polygon scanner device 14 simultaneously via the first beam path 28 and laser radiation 18 via the second beam path 30; or laser radiation 18 impinges on the second beam path 30 and laser radiation 18 via the third beam path 32; or laser radiation impinges on the first beam path 28 and laser radiation via the third beam path 32.

[0082] By alternating the exposure of the beam paths 28, 30, 32, laser radiation 18 strikes the polygon scanner device 14 without interruption. During the alternating exposure of the beam paths 28, 30, 32, no laser radiation strikes the polygon scanner device 14 at any time.

[0083] The points of incidence of the laser radiation 18 of the first beam path 28, the second beam path 30 and the third beam path 32 on the polygon scanner device 14 differ from one another.

[0084] Fig. 2 to 5 show that when laser radiation 18 strikes a mirror segment 20, the laser radiation 18 is deflected by reflection of the laser radiation 18 at the mirror segment 20 depending on the rotational position of the polygon scanner device 14.

[0085] The laser processing device 10 has a sensor 48 for detecting the rotational position of the mirror segments 20. The sensor 48 is connected to the laser beam source 12 for signal transmission. The laser beam source 12 applies laser radiation 18 to the beam paths 28, 30, 32 depending on the rotational position detected by the sensor 48. In the illustrated initial example, this is done by controlling the optical switches, so that the Fig. 2 to Fig. 5 during the rotation of the mirror segments 20.

[0086] Fig. 6 shows the workpiece 24 being processed by the laser processing device 10 using the laser radiation 18. The workpiece 24 is moved in the feed direction 52 during processing by the laser processing device 10.

[0087] The polygon scanner device 14 can be designed in such a way, for example by a suitable selection of the number of mirror segments, that an ideal scanning area 54 is obtained on the workpiece 24. Taking into account that the transitions between two adjacent mirror segments 20 are not exposed to laser radiation 18, a maximum scanning area 56 is obtained on the workpiece 24. In the illustrated embodiment of the Fig. 6, the maximum scanning range 56 is not utilized. The laser radiation 18 of the beam paths 28, 30, 32 impinges on the player segments 20 in such a way that a scanning range 58 results within the maximum scanning range 56. The scanning range 58 can be shifted within the maximum scanning range 56 by changing the alternating exposure of the beam paths 28, 30, 32. In other words, the difference between the maximum scanning range 56 and the scanning range 58 allows the scanning range 58 to be shifted within the maximum scanning range 56.

[0088] The rotating mirror segments 20 guide the laser radiation 18 across the workpiece 24 within the scanning area 58. At the time shown, the first beam path 28 is exposed to laser radiation 18 at an impact point 60 on the workpiece 24. The laser radiation 18 of the second beam path 30 strikes the workpiece 24 at an impact point 62. The third beam path 32 is exposed to laser power 18 and ends at an impact point 64 on the workpiece. Due to the rotation of the mirror segments 20, the impact points 60, 62, 64 are guided in the scanning direction 66 across the workpiece 24 along trajectories a, b, c.

[0089] To in Fig. At the time shown in Figure 6, the system switches from trajectory c to trajectory b, while the power application continues on trajectory a.

[0090] Fig. 7a) to 7c) each show a graph of amplitudes over a rotation angle of the polygon scanner device 14 for the trajectories a, b, c of Fig. 6. Fig. 7a) shows a temporal development of the exposure of the first beam path 28 to the laser radiation 18 over the angle of rotation of the polygon scanner device 14. Fig. 7b) shows a temporal development of the exposure of the second beam path 30 to the laser radiation 18 over the angle of rotation of the polygon scanner device 14. Fig. 7c) shows a temporal development of the exposure of the third beam path 32 to the laser radiation 18 over the angle of rotation of the polygon scanner device 14. Fig. 7d) shows a temporal development of the total laser radiation 18 impinging on the workpiece 24 and / or the polygon scanner device 14, over the angle of rotation of the polygon scanner device 14.

[0091] Fig. 7a) to 7c) show that the beam paths 28, 30, 32 are alternately exposed to laser radiation 18, whereby, regardless of the rotational position of the mirror segments 20, laser radiation 18 from at least two beam paths strikes the polygon scanner device 14 simultaneously.

[0092] Fig. 8 and 9a) to 9e) show a further embodiment for the application of beam paths according to Fig. 6 and Fig. 7a) to d), whereby identical and functionally equivalent elements are given the same reference numerals and in this respect reference is made to the above statements on the Fig. 1 to 7d), so that essentially only the existing differences are addressed.

[0093] Fig. 8 shows that laser radiation 18 is guided along four trajectories a, b, c, d over the workpiece 24. In other words, four beam paths are alternately applied for the purpose of guiding the laser radiation 18 along the trajectories a, b, c, d.

[0094] Each trajectory a, b, c, d has a plurality of interruptions 61. The interruptions 61 are formed by exposing the beam paths to pulsed laser radiation 18. The formation of the interruptions 61 depends on a pulse duration and a pulse repetition frequency of the pulsed laser radiation 18. Preferably, the interruption, pulsing, or modulation of the laser radiation 18 of the individual beam paths occurs by switching the laser power 18 between the beam paths.

[0095] In extension, the length of the interruptions and the trajectory during the power application on the workpiece can also be advantageously influenced by a scanning movement superimposed on the movement caused by the rotation of the polygon scanner device.

[0096] In the illustrated embodiment of the Fig. 8, the maximum scan area 56 is utilized. In other words, the scan area 58 and the maximum scan area 56 are the same size.

[0097] Fig. 9a) to d) each show a graph for an amplitude of the laser radiation 18 of one of the four beam paths over a rotation angle of the polygon scanner device 14 for the purpose of guiding the laser radiation 18 along the trajectories of Fig. 8. The individual pulses 63 of the pulsed laser radiation 18 are in Fig. 9a) to d). The pulses are applied with a temporal phase shift 65 between the pulses 63 of one beam path and the pulses 63 of a beam path following the beam path. Fig. 9e) shows a temporal development of the total laser radiation 18 impinging on the workpiece 24 and / or the polygon scanner device 14, over the angle of rotation of the polygon scanner device 14.

[0098] By switching the power within the scan period, efficient use of the beam source is enabled through continuous use of the beam source, without requiring a higher overall amplitude than that required for the individual beam paths. With respect to the laser irradiation envelope, the beam paths are thus simultaneously exposed to laser power 18. The intermittent and time-delayed irradiation of the individual beam paths within a scan period allows for efficient use of a continuously operated beam source.

[0099] Fig. 10 shows an exemplary sequence of a method for operating the polygon scanner device 14.

[0100] The method comprises the steps: a) rotating the mirror segments 20 of the polygon scanner device 14 about the rotation axis 38; e) generating the laser radiation 18 by means of the laser beam source 12; d) detecting the rotational position of the mirror segments 20; b) alternately applying laser radiation 18 to the first beam path 28 and alternately applying laser radiation 18 to the second beam path 30, which is different from the first beam path 28, while the mirror segments 20 rotate, so that laser radiation 18 of the first beam path 28 and laser radiation 18 of the second beam path 30 impinge on the polygon scanner device 14 simultaneously, wherein the alternating application of the first beam path 28 and the alternating application of the second beam path 30 in step b) take place depending on the detected rotational position of the mirror segments 20;and c) deflecting the laser radiation 18 of the first beam path 28 by reflecting the laser radiation 18 of the first beam path 28 by means of the mirror segments 20 of the polygon scanner device 14, and deflecting the laser radiation 18 of the second beam path 28 by reflecting the laser radiation 18 of the second beam path 30 by means of the mirror segments 20 of the polygon scanner device 14.;

Claims

[1] Method for operating a polygon scanner device (14), wherein the polygon scanner device (14) has a plurality of mirror segments (20) arranged side by side, the method comprising the steps: a) rotating the mirror segments (20) of the polygon scanner device (14) about a rotation axis (38), b) alternately applying laser radiation (18) to a first beam path (28) and alternately applying laser radiation (18) to a second beam path (30) different from the first beam path (28) while the mirror segments (20) rotate, so that laser radiation (18) of the first beam path (28) and laser radiation (18) of the second beam path (30) simultaneously impinge on the polygon scanner device (14), and c) Deflecting the laser radiation (18) of the first beam path (28) by reflecting the laser radiation (18) of the first beam path (28) by means of the mirror segments (20) of the polygon scanner device (14), and deflecting the laser radiation (18) of the second beam path (30) by reflecting the laser radiation (18) of the second beam path (30) by means of the mirror segments (20) of the polygon scanner device (14). [2] Method according to claim 1, - wherein the alternating exposure of the first beam path (28) and the alternating exposure of the second beam path (30) in step b) are carried out in such a way that laser radiation (18) of the first beam path (28) strikes a mirror segment (20) of the polygon scanner device (14) and, at the same time, laser radiation (18) of the second beam path (30) strikes a mirror segment (20) of the polygon scanner device (14) adjacent to the mirror segment (20) exposed to the laser radiation (18) of the first beam path (28). [3] Method according to one of the preceding claims, - wherein the alternating exposure of the first beam path (28) and the alternating exposure of the second beam path (30) in step b) are carried out in such a way that laser radiation (18) of the first beam path (28) strikes a mirror segment (20) of the polygon scanner device (14) and laser radiation (18) of the second beam path (30) simultaneously strikes the mirror segment (20) of the polygon scanner device (14) which is subjected to the laser radiation (18) of the first beam path (28). [4] Method according to one of the preceding claims, - wherein the laser radiation (18) of the first beam path (28) and / or the laser radiation (18) of the second beam path (30) strikes the mirror segments (20) at an angle orthogonal to the axis of rotation (38). [5] Method according to one of the preceding claims, - wherein the first beam path (28) and the second beam path (30) have an angle between them with an amount in a range from 0° to 360° / n, preferably from 0° to 360° / (3*n) or from 0° to 2*360° / (3*n), where n is a number of the mirror segments (20). [6] Method according to one of the preceding claims, - wherein the first beam path (28) has an angle between itself and a plane perpendicular to the axis of rotation (38) with an amount in a range from 0° to 30°, preferably from 3° to 10°, and / or - wherein the second beam path (30) has an angle between itself and a plane perpendicular to the axis of rotation (38) with an amount in a range from 0° to 30°, preferably from 3° to 10°. [7] Method according to one of the preceding claims, - wherein an imaginary extension of the first beam path (28) and an imaginary extension of the second beam path (30) have an intersection point (34) in a projection onto a plane orthogonal to the axis of rotation (38), - wherein a distance (36) between the rotation axis (38) and the intersection point (34) is smaller than distances (40) between the rotation axis (38) and the mirror segments (20). [8] Method according to one of the preceding claims, - wherein the alternating application in step b) is carried out in such a way that no laser radiation (18) strikes a transition (46) between two adjacent mirror segments (20) of the polygon scanner device (14). [9] Method according to one of the preceding claims, - wherein the method comprises the step before step b): d) determining a rotational position of the mirror segments (20), - wherein the alternating application of the first beam path (28) and the alternating application of the second beam path (30) in step b) take place as a function of the determined rotational position of the mirror segments (20). [10] Method according to one of the preceding claims, - wherein step b) comprises alternately applying laser radiation (18) to a third beam path (32) different from the first beam path (28) and the second beam path (30), so that laser radiation (18) of the third beam path (32) and laser radiation (18) of the first or second beam path (28, 30) impinge on the polygon scanner device (14) simultaneously, - wherein step c) comprises deflecting the laser radiation (18) of the third beam path (32) by reflecting the laser radiation (18) of the third beam path (32) by means of the mirror segments (20) of the polygon scanner device (14). [11] Method according to one of the preceding claims, - wherein step b) comprises alternating exposure to more than two beam paths. [12] Method according to one of the preceding claims, - wherein the alternating loading in step b) occurs several times in one scan period. [13] Method according to one of the preceding claims, - wherein the alternating application in step b) is carried out in such a way that a scanning area (58) is less than 80%, preferably 50%, of a maximum scanning area (56) delimited by the plurality of mirror segments (20) and / or the beam conditioning device (16). [14] Method according to one of the preceding claims, - wherein the alternating application in step b) is carried out by distributing the laser radiation (18) to the first beam path (28) and the second beam path (30) by means of coherent coupling. [15] Method according to one of the preceding claims, - wherein the laser radiation (18) of the first beam path (28) strikes the polygon scanner device (14) at a first angle of incidence and the laser radiation (18) of the second beam path (30) strikes the polygon scanner device (14) at a second angle of incidence, - wherein the method comprises the step: f) changing the first angle of incidence and / or the second angle of incidence by changing the first beam path (28) and / or the second beam path (30). [16] Method according to claim 15, - wherein the change in step f) is based on a measurement and / or a calculation of a distance between the laser radiation (18) of the first beam path (28) and the laser radiation (18) of the second beam path (30) on a workpiece (24). [17] Method according to one of the preceding claims, - whereby a combined effect is achieved by applying power to two beam paths on the workpiece in close succession, in that an effect occurs over a period of time which exceeds the period when only one beam path is applied by at least a factor of two. [18] Laser processing device (10), comprising: - a polygon scanner device (14) having a plurality of mirror segments (20) arranged side by side, - wherein the laser processing device (10) is designed to carry out a method according to one of the preceding claims. [19] Laser application device with rotating multi-segment mirror, - with several different feed beam paths directed towards the multi-segment mirror, - deflection beam paths resulting from reflection on the rotating mirror segments, - the device enables laser power to be supplied to an application area simultaneously from several deflection beam paths via a beam conditioning device, - whereby a spatially controlled power application in the application area is permitted by alternating modulation of the power application of individual feed beam paths, - where alternating modulation supports both simultaneous and alternating power application to different beam paths.

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