Apparatus and method for laser processing a workpiece - Patents.com

Abstract

The present invention relates to an apparatus for laser processing a workpiece (70), the apparatus comprising a beam shaping device (16, 16') for forming a focal zone (18) from an input laser beam (14) incident on the beam shaping device (16, 16') and a telescope device (34, 34') for imaging the focal zone (18) into a material (72) of the workpiece (70), the beam shaping device (16, 16') being used to impart a phase onto the beam cross section of the input laser beam (14) such that the focal zone (18) extends along a central longitudinal axis (40) that is curved in at least a portion thereof and the focal zone (18) has an asymmetric cross section in a plane oriented perpendicular to the central longitudinal axis (40).

Description

[Technical field]

[0001] The present invention relates to an apparatus for laser processing a workpiece.

[0002] The present invention also relates to a method for laser processing a workpiece. [Background technology]

[0003] (Patent Document 1) discloses a method for laser processing a transparent material, in which a laser beam including a burst of laser pulses is provided, and the pulses of the laser beam are focused, the focusing being performed by one or more optical elements having associated aberrations to generate a distributed focus along a longitudinal axis of the laser beam within the transparent material to form a beam waist at a location outside the transparent material, the focused laser beam having a sufficient energy density to form and maintain a continuous laser filament within the transparent material, and the laser energy imparted along the continuous laser filament results in an internal modification of the material, the internal modification having a shape defined by the continuous filament.

[0004] US Patent No. 5,399,633 discloses a method for beveling and / or chamfering the edges of a glass substrate using a laser.

[0005] US Pat. No. 5,399,433 discloses a cutting method for forming chamfered corners by different light patterns based on a Gaussian beam. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] European Patent No. 2859984B1 [Patent Document 2] U.S. Patent No. 10,173,916B2 [Patent Document 3] US Patent Application Publication No. 2020 / 0147729A1 [Patent Document 4] German Patent Application No. 102020207715.0 [Non-patent literature]

[0007] [Non-Patent Document 1] “Structured Light Fields: Applications in Optical Trapping, Manipulation and Organization”, M. Woerdemann, Springer Science & Business Media (2012), ISBN 978-3-642-29322-1 [Non-Patent Document 2] “Bessel-like optical beams with arbitrary trajectories”I.Chremmos et al.,Optics Letters,Vol.37,no.23,1 December 2012 [Non-Patent Document 3] “Generalized axicon-based generation of nondiffracting beams”K.Chen et al.,arXiv:1911.03103v1[physics.optics],8 November 2019 Summary of the Invention [Means for solving the problem]

[0008] The invention is based on the object of providing an apparatus as mentioned in the introduction, by means of which it is possible to laser process a workpiece along a curved processing line in a technically simple manner.

[0009] This object is achieved according to the invention in the case of an apparatus as described in the introduction, which comprises a beam shaping device for forming a focal zone from an input laser beam incident on the beam shaping device and a telescope device for imaging the focal zone into the material of the workpiece, the beam shaping device being used to impart a phase onto the beam cross-section of the input laser beam such that the focal zone extends along a central longitudinal axis which is curved in at least a particular portion and has an asymmetric cross-section in a plane oriented perpendicular to the central longitudinal axis.

[0010] The beam shaping device makes it possible to realize the mentioned focal zones in a technically simple manner and with few components by imparting a corresponding phase onto the beam cross section of the input laser beam.

[0011] In particular, the focal zone forms an interaction area, which, by applying this interaction area to the material of the workpiece, makes it possible to form local material modifications, in particular to separate the material.

[0012] Since the focal zone extends along a central longitudinal axis that is curved at least in certain parts, it is possible, for example, to machine a region that is curved at least in certain parts on the workpiece in a single pass and / or without the use of an optical unit, which makes it possible, for example, to modify a rounded region on the workpiece and / or to separate it from the workpiece, for example, so that an edge region of the workpiece can be rounded.

[0013] The asymmetric cross-section of the focal zone makes it possible to control and / or optimize the formation of the crack between adjacent modification areas in the advancement direction, in particular to position the crack at least approximately parallel to the shortest connection line between adjacent modification areas, thereby making it possible to achieve an optimal separation of the workpiece.

[0014] In particular, the phase distribution of the outcoupled partial beams on the beam exit surface of the beam shaping device may be discontinuous and / or have discontinuities, which makes it possible to form focal zones with asymmetric cross sections by interference, in particular non-fully constructive interference, of the outcoupled partial beams.

[0015] An asymmetric cross-section is understood to mean in particular that the beam diameter and / or the focal zone diameter have different diameters in the x and y directions, the x and y directions lying in particular in planes oriented perpendicular to each other and / or perpendicular to the beam propagation direction.

[0016] To determine the spatial dimensions of the focal zone, such as its length and / or diameter, the focal zone is observed with a modified intensity distribution having only intensity values ​​above a determined intensity threshold, which is in particular 50% of the overall intensity maximum of the actual intensity distribution. The length of the focal zone, or the diameter of the focal zone, is understood to mean the maximum length and / or maximum extent of the extent of the focal zone along the central longitudinal axis of the focal zone or in a plane oriented perpendicular to the central longitudinal axis, taken on the basis of the modified intensity distribution.

[0017] In particular, the central longitudinal axis of the focal zone is curved and / or continuously curved and / or curved over the entire length of the focal zone.

[0018] The object stated in the introduction is also achieved according to the invention in the case of an apparatus as stated in the introduction, which comprises a beam shaping device for forming a focal zone from an input laser beam incident on the beam shaping device and a telescope device used for imaging the focal zone into a material of a workpiece, the beam shaping device being used for imparting a phase onto the beam cross section of the input laser beam such that the focal zone extends along a central longitudinal axis which is curved at least in a particular portion, the telescope device being assigned a beam splitting device for splitting the partial beams output coupled from the beam shaping device into a plurality of polarized partial beams, each of which has one of at least two different polarization states, the telescope device having the beam splitting device being designed to focus the polarized partial beams into a first partial focal zone of a first partial beam having a first polarization state and into a second partial focal zone of a second partial beam having a second polarization state, so that the focal zone in at least a particular portion is formed by a spatial overlap of the first partial focal zone and the second partial focal zone, the focal zone having an asymmetric cross section in a plane oriented perpendicular to the central longitudinal axis.

[0019] In this variant of the invention, the asymmetric cross-section of the focal zone is realized by splitting the beam using a beam splitting device, so that the focal zone is formed in particular by incoherent overlap and / or superposition of a first partial beam with a first polarization state and a second partial beam with a second polarization state.

[0020] It is also possible in principle for partial beams with more than two different polarization states to be formed by the beam splitting device and / or for the focal zone to be formed from more than two different partial focal zones.

[0021] Overlap in particular means at least a partial spatial overlay, which is understood in particular to be used for an intensity addition of a first partial focal zone and a second partial focal zone.

[0022] Partial beams with different polarization states are understood to mean, in particular, linearly polarized partial beams in which the polarization directions of a first partial beam with a first polarization state and a second partial beam with a second polarization state are aligned at an angle of 90° to each other.

[0023] In particular, the focal zone, at least in certain parts, may be formed by an overlap of the spatial intensity distribution of a first partial focal zone with the spatial intensity distribution of a second partial focal zone, which makes it possible in a technically simple manner to form focal zones with asymmetric cross sections.

[0024] In principle, it is also possible for a focal zone to be completely formed by a spatial overlap of a first partial focal zone and a second partial focal zone.

[0025] It may be advantageous if the first partial focal zone extends along a first central longitudinal axis and the second partial focal zone extends along a second central longitudinal axis, the first central longitudinal axis and the second central longitudinal axis each having a curved form at least in certain parts, which makes it possible to form focal zones with curved shapes and asymmetric cross sections.

[0026] For the same reason, it may be advantageous if the first and second central longitudinal axes have a spatial offset in a direction oriented perpendicular to the first and / or second central longitudinal axes.

[0027] For the same reason, it may be advantageous if the first and second central longitudinal axes run at least approximately parallel to each other.

[0028] In particular, the first and second partial beams may be incoherent with respect to one another and / or may not have a fixed phase relationship with one another, so that the focal zone is formed in particular by an incoherent overlap and / or superposition of the first and second partial beams.

[0029] In particular, the beam splitting device may be arranged in the far field region of the telescope device and / or the beam splitting device may be arranged at least approximately in the focal plane of the telescope device, so that the beam splitting device can be integrated into the telescope device in a technically simple manner.

[0030] Far field region is understood to mean in particular a region in the beam path of a telescope device in which there is an annular intensity distribution around the optical axis of the telescope device.

[0031] In particular, the telescope device may have a first lens element and a second lens element spaced apart from the first lens element in the beam propagation direction, and the beam splitting device may be arranged between the first and second lens elements and / or the beam splitting device may be arranged approximately in a focal plane of at least the first lens element and / or the second lens element.

[0032] In particular, the beam splitting device may be or include a beam splitter optical unit, in particular a polarizing beam splitter optical unit, for example the beam splitter optical unit is made from or includes quartz crystal.

[0033] For example, the beam splitter device comprises at least one birefringent element, in particular at least one birefringent wedge element.

[0034] It may be advantageous if the beam splitting device comprises a birefringent polarizing element, which creates both a spatial and an angular offset between the first and second partial beams coupled out of the beam splitting device.

[0035] In particular, the beam splitting device comprises a further optical element, such as an isotropic element or a further birefringent polarizing element, arranged downstream of the birefringent polarizing element in the longitudinal direction.

[0036] In particular, the further optical element is designed to correct the spatial and / or angular offset between the first and second partial beams coupled out from the beam splitting device.

[0037] Preferably, the further optical element is configured to align the first partial beam parallel to the optical axis of the telescope device.

[0038] It may be advantageous if a beam splitting device is used to split the incident beam into respective different partial beams with different polarization states, the partial beams outputted from the beam splitting device and having different polarization states having an angular offset, which results in a spatial offset of the partial beams with different polarization states after they are imaged by the telescope device.

[0039] In particular, a first partial beam coupled out of the beam splitting device and having a first polarization state may be oriented parallel to the optical axis of the telescope device, which results in reduced alignment complexity.

[0040] In particular, the two above-mentioned variants of the device according to the invention each have one or more of the features and / or advantages that are explained below.

[0041] In particular, the focal zones and / or the intermediate images assigned to the focal zones may be formed by interference, in particular constructive interference in certain parts, of partial beams coupled out from the beam shaping device.

[0042] In particular, the telescope device may have a first lens element and a second lens element spaced apart from the first lens element in the beam propagation direction, the first lens element being used for input coupling of the beam into the telescope device and / or the second lens element being used for output coupling of the beam from the telescope device.

[0043] In particular, the telescope device may have a first lens element and a second lens element spaced apart from the first lens element in the beam propagation direction, the first lens element having a larger focal width than the second lens element.

[0044] In one embodiment, the first lens element of the telescope device is integrated into the beam shaping device or is arranged on the beam shaping device, in particular the functionality of the first lens element is integrated into the beam shaping device.

[0045] In particular, the central longitudinal axis of the focal zone in at least certain portions has a radius of curvature of at least 50 μm and / or at most 100 mm, and / or the central longitudinal axis of the focal zone has an average radius of curvature of at least 200 μm and / or at most 2 mm.

[0046] For example, the focal zones and / or the central longitudinal axes of the focal zones have a U-shape and / or a C-shape and / or a hyperbolic shape.

[0047] In particular, the focal zone and / or the central longitudinal axis of the focal zone may extend at least approximately along a circular arc.

[0048] For example, the center point angle of the arcuate portion is at least 1° and / or at most 90°.

[0049] For example, the focal zones and / or central longitudinal axes of the focal zones may extend along a quarter circle at least in certain portions.

[0050] In particular, the focal zones may have a spatially consecutive design. In particular, the first partial focal zone and / or the second partial focal zone have a spatially consecutive design.

[0051] In particular, the focal zones and / or the central longitudinal axes of the focal zones have a continuous and / or differentiable shape. In particular, the focal zones and / or the central longitudinal axes have no breaks and / or discontinuities.

[0052] In particular, the focal zone has a linear and / or elongated and / or long form.

[0053] For example, the length of the focal zone is more than 10 times, particularly more than 50 times, the maximum diameter of the focal zone.

[0054] In particular, the focal zone may have a length of at least 50 μm and / or at most 20 mm, in particular at least 500 μm and / or at most 2 mm.

[0055] In particular, the maximum diameter of the focal zone may be at least 500 nm and / or at most 5 μm.

[0056] It may be advantageous if the maximum diameter of the focal zone in a plane oriented perpendicular to the central longitudinal axis of the focal zone is at least approximately constant along the central longitudinal axis, which makes it possible to achieve approximately uniform processing of the material over the length of the focal zone.

[0057] It may be advantageous if a quasi-non-diffracting and / or Bessel-like beam can be generated or can be generated by a beam shaping device, so that in particular a focal zone is provided with a transverse intensity distribution that is at least approximately constant in the longitudinal direction, where transverse intensity distribution is understood to mean the intensity distribution in a plane oriented perpendicular to the central longitudinal axis of the focal zone.

[0058] In particular, the focal zone has a near-non-diffractive and / or Bessel-like beam profile.

[0059] Quasi-non-diffracting beams and / or Bessel-like beams should in particular be understood to mean beams whose transverse intensity distribution is propagation-invariant, in particular in the case of quasi-non-diffracting beams and / or Bessel-like beams, the transverse intensity distribution in the longitudinal direction of the beam and / or in the direction of beam propagation is substantially constant.

[0060] A transverse intensity distribution should be understood to mean an intensity distribution lying in a plane oriented perpendicular to the longitudinal direction of the beam and / or the direction of beam propagation.

[0061] For the definition and properties of quasi-non-diffracting beams, see the following document: (Non-Patent Document 1).

[0062] The formation and properties of quasi-non-diffracting and / or Bessel-like beams with curved shapes are mentioned in a scientific publication by I. Chremmos et al. (Non-Patent Document 2).

[0063] The formation and properties of quasi-non-diffracting and / or Bessel-like beams with asymmetric cross-sections are mentioned in a scientific publication by K. Chen et al. (Non-Patent Document 3).

[0064] In particular, the focal zone may have an elliptical cross-section in a plane oriented perpendicular to the central longitudinal axis of the focal zone, which makes it possible, among other things, to control the formation and / or orientation of cracks formed during laser processing of the workpiece.

[0065] For the same reason, it may be advantageous if the maximum diameter of the cross-sectional ellipse of the focal zone is aligned at least approximately parallel to the advance direction in which the workpiece moves relative to the focal zone to form the processing line and / or processing surface, so that cracks formed in particular during laser processing are oriented at least approximately parallel to the advance direction.

[0066] In particular it may be advantageous if an intermediate image of the focal zone is formed by the beam shaping device and the focal zone is formed by imaging the intermediate image by a telescope device, which can be used in particular to adapt the length of the focal zone depending on the use.

[0067] In particular, in the beam propagation direction, the intermediate image may be arranged between the beam shaping device and a second lens element for output coupling of the beam from the telescope device and / or between the beam shaping device and a beam splitting device which splits the partial beam output coupled from the beam shaping device into a plurality of polarized partial beams.

[0068] It may be advantageous if the beam shaping device and / or the beam splitting device are rotatable relative to, and in particular around, the optical axis of the telescope device, which allows for adapting the alignment of the focal zone with respect to the workpiece.

[0069] In particular, the apparatus comprises a laser source for providing an input laser beam, in particular a pulsed laser beam or an ultrashort pulsed laser beam may be provided by the laser source.

[0070] For example, the wavelength of the input laser beam is at least 300 nm and / or at most 1500 nm. For example, the wavelength is 515 nm or 1030 nm.

[0071] In particular, the processing beam has an average power of at least 1 W to 1 kW. For example, the processing beam includes pulses having a pulse energy of at least 10 μJ and / or up to 50 mJ. The processing beam may include individual pulses or bursts, with the bursts having 2 to 20 sub-pulses, in particular having a time interval of about 20 ns.

[0072] It may be advantageous if the beam shaping device comprises at least one diffractive optical element or is in the form of a diffractive optical element.

[0073] In principle it is also possible for the beam shaping device to be in the form of a refractive and / or reflective optical element.

[0074] For example, the beam shaping device is or includes an axicon-like element.

[0075] It may be advantageous if the phase distribution of the partial beams coupled out on the beam exit surface of the beam shaping device is asymmetric and / or not rotationally symmetric. In particular, the phase distribution is asymmetric and / or not rotationally symmetric with respect to the beam axis of the input laser beam and / or with respect to the optical axis of the beam shaping device. This makes it possible to generate focal zones, for example, in the form of curved Bessel-like beams and / or accelerated Bessel-like beams.

[0076] It may be advantageous if the apparatus comprises a further telescope device for controlling the diameter of the input laser beam incident on the beam shaping device, which makes it possible to control and / or adjust the length of the focal zone.

[0077] For example, the further telescope device is arranged upstream of the beam shaping device in the beam propagation direction.

[0078] According to the present invention, a method for laser processing a workpiece is provided, in which a beam shaping device is used to form a focal zone from an input laser beam incident on the beam shaping device, the focal zone being or being able to be imaged into the material of the workpiece by a telescope device, and the beam shaping device is used to impart a phase onto the beam cross section of the input laser beam such that the focal zone extends along a central longitudinal axis that is curved in at least a particular portion, and the focal zone has an asymmetric cross section in a plane oriented perpendicular to the central longitudinal axis.

[0079] According to the invention, a further method for laser processing a workpiece is provided, in the process of which a beam shaping device is used to form a focal zone from an input laser beam incident on the beam shaping device, the focal zone being or can be imaged into the material of the workpiece by a telescope device, the beam shaping device is used to impart a phase onto the beam cross-section of the input laser beam such that the focal zone extends along a central longitudinal axis that is curved at least in a specific portion, and a beam splitting device assigned to the telescope device is used to split the partial beams output-coupled from the beam shaping device into a plurality of polarized partial beams, each of which has one of at least two different polarization states, the polarized partial beams being focused into a first partial focal zone of a first partial beam having a first polarization state and into a second partial focal zone of a second partial beam having a second polarization state, so that the focal zone in at least a specific portion is formed by a spatial overlap of the first partial focal zone and the second partial focal zone, the focal zone having an asymmetric cross-section in a plane oriented perpendicular to the central longitudinal axis.

[0080] The method according to the invention has in particular one or more of the features and / or advantages of the device according to the invention described above. Advantageous configurations of the method according to the invention have already been explained in connection with the device according to the invention.

[0081] In particular, the workpiece may be made of and / or include a material that is transparent to the wavelength of the input laser beam and / or the wavelength of the focal zone formed from the input laser beam. The workpiece material may, for example, be or include glass.

[0082] A transparent material is understood in particular to mean a material through which at least 70%, in particular at least 80%, in particular at least 90% of the laser energy of the processing beam is transmitted.

[0083] In particular, the focal zone is applied to the workpiece for carrying out the laser processing, and in particular the workpiece may be moved relative to the focal zone along a processing line or processing plane, which makes it possible to form material modifications of the workpiece arranged along the processing line or processing plane.

[0084] In particular, after the laser processing is performed, the workpiece may or may not be separated along the processing line and / or processing plane.

[0085] It may be advantageous if material of the workpiece is separable or separable along processing lines and / or processing planes by applying thermal loads and / or mechanical stresses and / or by etching with at least one wet chemical solution.

[0086] In particular, the input laser beam may be a pulsed laser beam or an ultrashort pulsed laser beam and / or the focal zone may be formed by a pulsed laser beam or an ultrashort pulsed laser beam.

[0087] In particular, an axis system is provided for moving and / or tilting the workpiece relative to the focal zone.

[0088] Electronic regulation may be provided to control a laser source for supplying the input laser beam, including spatially resolved pulse control, particularly pulse on demand.

[0089] In particular, a workpiece mount is provided, particularly for a workpiece having a non-reflective and / or highly scattering surface.

[0090] Unless otherwise stated, the above mentioned characteristics of the focal zone essentially relate to the characteristics of the focal zone in air and / or the characteristics of the focal zone outside the workpiece.

[0091] In particular, the terms "about" and "at least about" are generally understood to mean a deviation of 10% or less. Unless otherwise specified, the terms "about" or "at least about" are specifically understood to mean that the actual value and / or distance and / or angle deviates from the ideal value and / or distance and / or angle by 10% or less.

[0092] The following description of preferred embodiments in conjunction with the drawings will serve to explain the invention in more detail. [Brief description of the drawings]

[0093] [Figure 1] 1 is a schematic cross-sectional view of one embodiment of an apparatus for laser processing a workpiece, showing two different variants. [Diagram 2] 3 is a schematic cross-sectional view in a partial area of ​​a further embodiment of an apparatus for laser processing of a workpiece, in which two different variants are shown. [Diagram 3] 5A is a schematic diagram of the phase distribution of partial beams on the beam exit surface of a first embodiment of the beam shaping device of the apparatus; FIG. [Figure 4] FIG. 13 shows the intensity distribution of a simulated focal zone having a curved profile in the zx plane oriented parallel to the central longitudinal axis of the focal zone. [Diagram 5] FIG. 13 is a cross-sectional view of a simulated focal zone intensity distribution in an xy plane oriented perpendicular to the central longitudinal axis of the focal zone. [Figure 6] Schematic diagram of the phase distribution of partial beams on the beam exit surface of a further embodiment of the beam shaping device of the apparatus. [Figure 7] 1 is a schematic cross-sectional view of a first embodiment of a beam splitting device; [Figure 8] 4A-4C are schematic cross-sectional views of further embodiments of beam splitting devices; [Figure 9a]1 is a schematic illustration of a focal zone in a cross section parallel to a central longitudinal axis of the focal zone, the focal zone being formed by a spatial overlap of a first partial focal zone and a second partial focal zone; [Figure 9b] FIG. 9b is a schematic cross-sectional view of the focal zone according to FIG. 9a in an xy plane oriented perpendicular to the central longitudinal axis of the focal zone. [Figure 10a] FIG. 2 is a schematic cross-sectional view of the intensity distribution of the focal zone in an xy plane oriented perpendicular to the central longitudinal axis of the focal zone. [Figure 10b] FIG. 10b shows the intensity distribution of the focal zone according to FIG. 10a in the x-direction at y=0. [Figure 10c] FIG. 10b shows the intensity distribution of the focal zone according to FIG. 10a in the y direction at x=0. [Figure 11] 1 is a schematic cross-sectional view of a workpiece being machined by a focal zone along a machining line and / or machining plane. [Figure 12a] FIG. 1 is a perspective view of an example of a workpiece being separated into two distinct segments along a processing line and / or processing plane. [Figure 12b] 13 is a perspective view of a further example of a workpiece separated into two different segments along a processing line and / or processing plane. FIG. [Figure 13] 1 is a schematic cross-sectional view of a partial area of ​​a workpiece on a processing line and / or processing surface, in which cracks are formed between correction areas spaced apart from one another; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0094] Elements that are the same or have equivalent functionality are designated by the same reference numbers in all exemplary embodiments.

[0095] A first exemplary embodiment of an apparatus for laser processing a workpiece is shown in Figure 1 and is designated 10 therein. The apparatus 10 can be used to create locally present material modifications on the workpiece, such as defects on the sub-micron or atomic scale, which weaken the material, allowing, for example, for a subsequent step to separate the workpiece into two different segments.

[0096] In particular, the apparatus 10 comprises a laser source 12 for providing an input laser beam 14. The input laser beam 14 is in particular a pulsed laser beam and / or an ultrashort pulsed laser beam. For example, the input laser beam 14 is a Gaussian beam and / or has a diffractive beam profile.

[0097] The apparatus 10 comprises a beam shaping device 16 into which an input laser beam 14 can be coupled. In particular, the input laser beam 14 is coupled into the beam shaping device 16 in an operative state of the apparatus 10.

[0098] The input laser beam 14 propagates along a longitudinal direction z. In particular, longitudinal direction z is understood to mean the main beam propagation direction of the input laser beam 14 and / or of a beam formed from the input laser beam 14 through the apparatus 10.

[0099] The wavelength of the input laser beam 14 is, for example, 515 nm or 1030 nm.

[0100] The beam shaping device 16 imparts a phase onto the beam cross-section of the input laser beam 14 to generate an elongated focal zone 18. The cross-sectional direction of this beam cross-section is oriented perpendicular to the longitudinal direction z and / or to the beam propagation direction.

[0101] An input laser beam 14 impinges on the beam shaping device 16 at a beam inlet face 20 and is coupled into the beam shaping device. At a beam exit face 22 located opposite the beam inlet face 20, a phase modulated partial beam 24 is coupled out of the beam shaping device 16.

[0102] The partial beams 24 coupled out of the beam shaping device 16 are mutually coherent partial beams, ie the different partial beams 24 have a fixed phase relationship to one another.

[0103] Furthermore, the partial beams 24 exiting the beam shaping device 16 are inclined with respect to the input laser beam 14 incident on the beam shaping device 16 and / or with respect to the optical axis 25 of the beam shaping device 16 by a cone angle β1. In particular, the partial beams 24 have a conical profile and / or a conical envelope.

[0104] The interference of the partial beams 24 causes the formation of an intermediate image 26, which is assigned to the focal zone 18 and is arranged downstream of the beam shaping device 16 in the longitudinal direction z. The focal zone 18 and / or the intermediate image 26 of the focal zone 18 have an elongated and / or long shape.

[0105] In particular, the intermediate image 26 and / or the focal zone 18 are aligned in the longitudinal direction z. For example, the main extension direction of the intermediate image 26 and / or the focal zone 18 is oriented in the longitudinal direction z and / or is oriented parallel to the optical axis 25.

[0106] The intermediate image 26 extends along a central longitudinal axis 27 (shown by a dotted line in FIG. 1 ). In this respect, the central longitudinal axis 27 is in particular an axis of symmetry of the intermediate image 26 in the longitudinal direction.

[0107] The first beam shaping device 16 is in particular in the form of a diffractive optical element, for example the first beam shaping device is in the form of an axicon-like element.

[0108] The phase profile imparted to the partial beams 24 by the beam shaping device 16 is in particular such that the intermediate image 26 and / or the focal zone 18 has a quasi-non-diffractive and / or Bessel-like beam profile.

[0109] Furthermore, the phase profile imparted to the partial beam 24 is such that the intermediate image 26 and / or the focal zone 18 have a curved shape. Correspondingly, the central longitudinal axis 27 along which the intermediate image 26 extends has a curved shape.

[0110] An example of a phase distribution imparted to a partial beam 24 by the beam shaping device 16 is shown in Fig. 3. The two-dimensional phase distribution of the partial beam 24 leaving the beam shaping device 16 on the beam exit face 22 is depicted in Fig. 3 by a greyscale profile with an assigned greyscale range going from white (phase +Pi) to black (phase -Pi).

[0111] The beam exit surface 22 and / or the phase distribution shown lie in a plane oriented transversely, in particular perpendicularly, to the longitudinal direction z.

[0112] Each partial beam 24 leaving the beam shaping device 16 on the beam exit face 22 at the spatial position X1, Y1 is assigned a phase displacement value determined within the range from -Pi to +Pi, which in the example according to FIG. 3 can be seen with reference to the phase distribution shown therein.

[0113] 3, the phase distribution on the beam exit surface 22 has an asymmetric, in particular non-rotationally symmetric, profile, which imparts a phase profile to the partial beams 24 such that a focal zone with a curved profile is formed by interference of the partial beams 24. As a result, the intermediate image 26 and / or the focal zone 18 have a curved profile.

[0114] 3 has one or more discontinuities 28 at which the phase profile between two adjacent sub-regions 30a, 30b is discontinuous. For example, the phase displacement and / or phase discontinuity between adjacent sub-regions 30a, 30b has a value of Pi.

[0115] A discontinuity 28 is understood to mean a separation point and / or a separation line between a first partial region 30a and a second partial region 30b adjacent to the first partial region 30a.

[0116] In particular, the phase difference between a first boundary point 32a on the discontinuity 28 of the first sub-region 30a and a second boundary point 32b on the discontinuity 28 of the second sub-region 30b is Pi.

[0117] In particular, the adjacent partial regions 30a and 30b are locally continuous partial regions.

[0118] Thanks to the phase distribution which is discontinuous and / or comprises discontinuities, the phase profile imparted by the beam shaping device 16 to the partial beams 24 is such that the intermediate image 26 and / or the focal zone 18 have an asymmetric beam cross-section. For the intermediate image 26, the cross-section of the beam cross-section is oriented perpendicular to the longitudinal central axis 27.

[0119] The apparatus 10 comprises a telescope device 34 arranged downstream of the intermediate image 26 in the beam propagation direction and / or in the longitudinal direction z. The focal zone 18 is formed by imaging the intermediate image 26 by said telescope device 34, in particular the telescope device 34 performing the imaging in a reduced size.

[0120] The telescope device 34 has a first lens element 36 and a second lens element 38 spaced apart from the first lens element 36 in the longitudinal direction z.

[0121] The first lens element 36 is the long focal length lens element and / or the input lens element of the telescope device 34. The second lens element 38 is the output lens element and / or the short focal length lens element of the telescope device 34. The second lens element 38 is in particular in the form of and / or has the function of an objective lens.

[0122] The first lens element 36 and / or the second lens element 38 do not necessarily have to be integrally formed. In particular, the first lens element 36 and / or the second lens element 38 in each case may be formed from or include multiple optical components.

[0123] The first focal length f1 of the first lens element 36 is greater than the second focal length f2 of the second lens element 38. In particular, the ratio f1 / f2 is at least 5 and / or at most 50.

[0124] The telescope device 34 makes it possible to illuminate and / or image the focal zone 18 onto the workpiece to be processed. In particular, the telescope device 34 makes it possible to adapt the spatial dimensions of the focal zone 18 to process the workpiece.

[0125] In particular, focal zone 18 is understood to mean a focal region having at least approximately constant intensity and extending along a central longitudinal axis 40 (shown by a dotted line in FIG. 1 ), which in this respect is in particular the axis of symmetry of focal zone 18 in the longitudinal direction.

[0126] In particular, focal zone 18 extends along a central longitudinal axis 40 and has a focused region having at least a substantially constant intensity.

[0127] In particular, the focal zones 18 have a spatially continuous design, ie the focused intensity areas of the focal zones 18 in each case have a spatially continuous design.

[0128] However, it is also possible in principle for the intensity of the focal zone 18 to vary along the central longitudinal axis and / or to be zero at isolated points.

[0129] In particular, focal zone 18 is understood to mean a focused region within which the intensity of the laser radiation is at least sufficiently large that, when focal zone 18 is applied to the material of the workpiece, modified regions are formed in the material. In particular, the material can be separated in these modified regions.

[0130] The central longitudinal axis 40 of the focal zone 18 has at least a portion and / or a continuously curved shape.

[0131] One exemplary embodiment of the focal zone 18 is shown in Fig. 4, which shows the intensity distribution in a zx plane oriented parallel to the central longitudinal axis 40. Lighter grayscale values ​​represent greater intensity. In the exemplary embodiment according to Fig. 4, the focal zone 18 has an arc shape and / or a C-shape.

[0132] The focal zone 18 is understood to mean in particular the overall intensity maximum distribution 42, which has a spatially continuous design. In particular, only this overall intensity maximum distribution 42 is relevant for interaction with the material to be processed in order to form the modifications.

[0133] The maximum intensity distribution 42 is in particular surrounded by secondary intensity distributions 44. These secondary intensity distributions 44 are in particular arranged around and / or spaced apart from the maximum intensity distribution 42. The secondary intensity distributions 44 are in particular secondary maxima or include secondary maxima.

[0134] In particular, the secondary intensity distribution 44 is not significant for the laser processing of the workpiece since, thanks to its lower intensity, there is no and / or the formation of modifications in the material of the workpiece is negligible.

[0135] The focal zone 18 has an asymmetric beam cross-section, with the cross-section oriented perpendicular to the central longitudinal axis 40. Figure 5 shows an example of a focal zone 18 in the xy plane oriented perpendicular to the central longitudinal axis 40.

[0136] In particular, focal zone 18 has a diameter dx in the x-direction and a diameter dy in a y-direction oriented perpendicular to the x-direction, the x-direction and y-direction lying in a plane oriented perpendicular to central longitudinal axis 40.

[0137] In particular, focal zone 18 may have an elliptical beam cross-section, where dx and dy are different, e.g., dx is oriented parallel to the semi-major axis and dy is oriented parallel to the semi-minor axis of the assigned ellipse.

[0138] In a second variant of the apparatus 10, in contrast to the first variant described above, a beam shaping device 16' is used to form an intermediate image 26' which is assigned to the focal zone 18 and has an at least approximately symmetrical beam cross section.

[0139] In particular, the beam shaping device 16' and intermediate image 26' each have one or more features and / or advantages of the beam shaping device 16 described above and the intermediate image 26 described above.

[0140] The intermediate image 26' extends along a central longitudinal axis 27 and has, in particular, a quasi-non-diffractive and / or Bessel-like beam profile.

[0141] On the beam exit surface 22, the partial beams 24 leaving the beam shaping device 16' have a different phase distribution than in the case of the beam shaping device 16 described above.

[0142] An example of a phase distribution imparted to the partial beams 24 by the beam shaping device 16' is shown in Fig. 6 in the form of a grey-scale distribution (similarly to Fig. 3). The phase distribution on the beam exit surface 22 has an asymmetric, in particular non-rotationally symmetric profile. This imparts to the partial beams 24 a phase profile such that focal zones with a curved profile are formed by interference of the partial beams 24. As a result, the intermediate image 26' and / or the focal zone 18 have a curved profile.

[0143] In particular, the phase distribution shown in Fig. 6 is continuous, in particular entirely continuous. In particular, the phase distribution shown in Fig. 6 does not have any breaks and / or discontinuities. This gives the partial beams 24 a phase profile such that a focal zone with a symmetric beam cross-section is formed by the interference of the partial beams 24. As a result, the intermediate image 26' has a symmetric beam cross-section, the cross-sectional direction of which is oriented perpendicular to the central longitudinal axis 27.

[0144] To achieve an asymmetric beam cross-section in the focal zone 18, the apparatus 10 of this second variant comprises a beam splitting device 46 (shown in dashed lines in FIG. 1 ) assigned to the telescope device 34. For example, the beam splitting device 46 is part of the telescope device 34 and / or is arranged in the beam path of the telescope device 34. For example, the beam splitting device 46 is or comprises a polarizing beam splitter optical unit.

[0145] The beam splitting device 46 is particularly arranged in the far field region 48 and / or in a focal plane 50 of the telescope device 34. For example, the focal plane 50 is the focal plane of the first lens element 36 and / or the second lens element 38.

[0146] The partial beams 24 outcoupled from the beam shaping device 16' and / or the beams emerging from the intermediate image 26' are incident on the beam splitting device 46 as incident beams 52. These incident beams 52 are split by the beam splitting device 46 into different partial beams 54a, 54b each having a different polarization state.

[0147] In the example of the beam splitting device 46 shown in FIG. 7, the incident beam 52 is split by the beam splitting device 56 into a first partial beam 54a having a first polarization state and a second partial beam 54b having a second polarization state, respectively.

[0148] The first and second polarization states are in particular polarization states oriented approximately perpendicularly parallel to one another and / or linear polarization states. In particular, the first partial beam 54a and the second partial beam 54b are polarized such that the electric field lies in a plane perpendicular to the longitudinal direction z and / or to the beam propagation direction (transverse power).

[0149] The first partial beam 54a has a spatial offset Δx and an angular offset Δα with respect to the second partial beam 54b.

[0150] In particular, the first partial beam 54a is oriented at least approximately parallel to an optical axis 56 of the telescope device 34, which is for example oriented parallel to or coincident with the optical axis 25 of the beam shaping device 16, 16'.

[0151] The first partial beam 54a coupled out from the beam splitting device 46 is imaged by the telescope device 34 and / or by the second lens element 38 into a first partial focal zone 58a. Correspondingly, the second partial beam 54b coupled out from the beam splitting device 46 is imaged by the telescope device 34 and / or by the second lens element 38 into a second partial focal zone 58b (Figures 9a and 9b).

[0152] Due to the angular offset of the first partial beam 54a and the second partial beam 54b, the result after focusing by the telescope device 34 is a spatial offset Δb between the first partial focal zone 58a and the second partial focal zone 58b in a direction oriented perpendicular to the longitudinal central axis 40.

[0153] The first partial focal zone 58a extends along a first central longitudinal axis 60a and the second partial focal zone 58b extends along a second central longitudinal axis 60b. The first central longitudinal axis 60a and the second central longitudinal axis 60b extend in the longitudinal direction z and / or the beam propagation direction.

[0154] In particular, the first partial focal zone 58a and the second partial focal zone 58b each have an at least approximately symmetric beam cross-section, with the cross-sectional direction oriented perpendicular to the first central longitudinal axis 60a and the second central longitudinal axis 60b, respectively.

[0155] The focal zone 18 is formed by at least partial spatial overlap and / or superposition of a first partial focal zone 58a and a second partial focal zone 58b, the beam cross section of which is thereby formed being asymmetric, in particular elliptical (see Figures 9a and 9b).

[0156] The first partial beam 54a and the second partial beam 54b are mutually incoherent partial beams and / or do not have a fixed phase relationship with respect to each other, and therefore in particular the first partial beam 54a and the second partial beam 54b do not interfere with each other. In case of a spatial overlap of the first partial beam 54a and the second partial beam 54b, the result is therefore the addition of the respective intensity of the first partial beam 54a and the respective intensity of the second partial beam 54b.

[0157] 9a and 9b, the first central longitudinal axis 60a is oriented at least approximately parallel to the second central longitudinal axis 60b. The central longitudinal axis 40 of the focal zone 18 is symmetrical and / or central with respect to the first central longitudinal axis 60a and the second central longitudinal axis 60b.

[0158] 7, the beam splitting device 46 comprises a birefringent polarizing element 62. Both a spatial offset Δx and an angular offset Δα are generated between the first partial beam 54a and the second partial beam 54b by the birefringent polarizing element 62.

[0159] The beam entrance face 64 and / or the beam entrance surface of the beam splitting device 46 are formed on this birefringent polarizing element 62 .

[0160] The optical axis 66 of the birefringent polarizing element 62 is oriented at an angle of, for example, 45° to the beam entrance face 64 and / or to the optical axis 56 of the telescope device 34 .

[0161] The beam splitting device 46 also comprises an isotropic element 68 arranged downstream of the birefringent polarizing element 62 in the longitudinal direction z. The first partial beam 54a is aligned parallel to the optical axis 56 by this isotropic element 68.

[0162] The birefringent polarizing element 62 and / or the isotropic element 68 may, for example, have a wedge-shaped design.

[0163] The further embodiment shown in FIG. 8 differs essentially from the embodiment according to FIG. 7 in that the first partial beam 54a is oriented parallel to and lies within the optical axis 56 of the telescope device 34.

[0164] For the parallel alignment of the first partial beams 54a with respect to the optical axis 56 and their positioning on the optical axis 56, the embodiment according to FIG. 8 comprises two birefringent polarizing elements 62 arranged one behind the other.

[0165] In all other respects, the embodiment according to FIG. 8 has essentially the same structure and / or the same mode of operation as the embodiment according to FIG. 7, and therefore reference is made in this respect to the above description thereof.

[0166] Regarding the mode of operation and design of the beam splitting device 46, reference is made to commonly assigned US Pat. No. 6,220,333, filed on June 22, 2020, the entire contents of which are expressly referenced.

[0167] A further embodiment of an apparatus 10' for laser processing a workpiece (FIG. 2) differs from the above-described embodiment essentially in that an alternative variant of the telescope device 34' is provided.

[0168] In the case of the telescope device 34', the first lens element 36 is either integrated in the beam shaping device 16, 16' or is arranged at the beam exit surface 22 of the beam shaping device. This enables in particular the apparatus 10' to have a particularly compact configuration and / or a configuration with a reduced number of individual components.

[0169] For example, the functionality of the first lens element 36 is integrated into the beam shaping device 16, 16'.

[0170] The intermediate image 68 formed in the case of the device 10' and assigned to the focal zone 18 does not necessarily have the properties of the intermediate images 26, 26' described above. In comparison with the intermediate images 26, 26', the intermediate image 68 has a different form thanks to the beam profile which is modified in this case. In particular, the intermediate image 68 has a different shape in comparison with the intermediate images 26, 26' and / or the focal zone 18.

[0171] In all other respects, the device 10' has essentially the same structure and the same mode of operation as the variant of device 10 described above, and reference is therefore made in this respect to that description.

[0172] To determine the length l of the focal zone 18 in the direction of the central longitudinal axis 40 and / or the diameters dx, dy in the x and y directions oriented perpendicular to the central longitudinal axis 28, respectively, consideration is given to a modified intensity distribution having only intensity values ​​above a determined intensity threshold, which is in particular 50% of the global intensity maximum of the actual intensity distribution. This is shown diagrammatically in Figures 10a, 10b and 10c for the diameters dx, dy of the focal zone 18.

[0173] The length l of the focal zone 18 is understood to mean, for example, the maximum length and / or maximum extent of the extent of the focal zone 18 along the central longitudinal axis 40, adopted based on the modified intensity distribution. In the example shown in Fig. 9a, the length l means, for example, the corresponding curved length and / or arc length and / or arc length of the focal zone 18.

[0174] The apparatus 10 may comprise a further telescope device 69 arranged between the laser source 12 and the beam shaping device 16, 16' in the longitudinal direction z. This further telescope device 42 may be used to control and / or adjust the diameter d0 of the input laser beam 14 incident on the beam shaping device 16, 16'.

[0175] By controlling and / or adjusting the diameter d0, it is possible to control and / or adjust the length l of the focal zone and / or the length of the intermediate images 26, 26' of the focal zone 18. The length l increases as the diameter d0 increases.

[0176] The device 10, 10' according to the invention operates as follows.

[0177] To perform a machining operation on a workpiece 70 with the apparatus 10 , 10 ′, the focal zone 18 is applied to material 72 of the workpiece 70 and the focal zone 18 is moved relative to the material 72 .

[0178] In particular, material 72 is a material that is transparent or partially transparent to the wavelengths of input laser beam 14 and / or the wavelengths of focal zone 18 formed from input laser beam 14. For example, material 72 is a glass material.

[0179] The focal zone 18 is in particular moved along a given processing line 74 and / or processing plane (FIGS. 11, 12a and 12b). The processing line 74 may, for example, have straight and / or curved portions.

[0180] By applying the focal zone 18 to the material 72, localized material modifications are formed in the material 72 over the processing line 74 and / or processing surface that reduce the strength of the material 72 over the processing line 74 and / or processing surface.

[0181] This allows for the separation of material 72 into two distinct segments after material modifications have been formed on processing line 74 and / or processing surface, for example by application of a mechanical force.

[0182] 11, 12a and 12b show, for example, the processing of a material 72 according to a first variant of a focal zone 18a extending from a first outer surface 74 to a second outer surface 76 located opposite the first outer surface 74, the first outer surface 74 being spaced apart from the second outer surface 76 by a material thickness D of the material 72. In the example shown, the first focal zone 18a extends at least over the entire material thickness D. This makes it possible, for example, to separate a segment 80 from the material 72, the segment 80 extending over the entire material thickness D.

[0183] A second variant of the focal zone 18b extends through the material 72 in certain parts. This makes it possible, for example, to separate a segment 82 having a quarter-circle profile from the material 72 (FIG. 12b). The focal zone 18b makes it possible, for example, to round an edge 84 of the material 72.

[0184] The advance direction 86 of the focal zone 18 relative to the material 72 is oriented parallel to the process line 74 .

[0185] 13 illustrates multiple modified regions 88 formed by relative movement of focal zone 18 with respect to material 72. In particular, the cross-section of focal zone 18 is aligned such that the major axis of the cross-section is oriented at least approximately parallel to advancement direction 86 and / or such that the minor axis of the cross-section is oriented transversely, and in particular perpendicular to, advancement direction 86.

[0186] 13, the focal zone 18 has an elliptical cross-section. The larger semi-axis and / or the larger diameter dy are oriented at least approximately parallel to the advance direction 86.

[0187] This makes it possible to form cracks 90 between adjacent modified regions 88 in a particularly controlled manner, so that an optimal separation of the material 72 can be achieved.

[0188] In particular, the cracks 90 are aligned at least approximately parallel to the shortest connecting line between adjacent modified regions 88 . [Explanation of symbols]

[0189] β1 Cone angle Δx spatial offset Δb spatial offset Δα Angular offset dx diameter in x direction dy Diameter in the y direction d0 diameter D material thickness l Length z Longitudinal direction 10, 10' device 12 Laser source 14 Input laser beam 16, 16' Beamforming Device 18 Focal Zones 18a, 18b Focal Zones 20 Beam entrance surface 22 Beam exit surface 24 Partial Beam 25 Optical axis 26, 26' Intermediate image 27 Longitudinal central axis 28 Discontinuity 30a First Partial Region 30b Second partial area 32a First boundary point 32b Second Boundary Point 34, 34' Telescope Device 36 First Lens Element 38 Second Lens Element 40 Longitudinal central axis 42 Overall maximum intensity distribution 44 Secondary intensity distribution 46 Beam splitting device 48 far field area 50 focal plane 52 Incident beam 54a First partial beam 54b Second partial beam 56 Optical axis 58a First partial focal zone 58b Second partial focal zone 60a First longitudinal central axis 60b Second longitudinal central axis 62 Birefringent Polarizing Elements 64 Beam entrance surface 66 Optical axis 68 Intermediate image 69 Further Telescopic Devices 70 work pieces 72 Material 74 Processing line 76 First Outer Surface 78 Second Outer Surface 80 Segments 82 Segments 84 Edge 86 Forward direction 88 Correction area 90 Crack

Claims

1. An apparatus for laser processing a workpiece (70), comprising: a beam shaping device (16, 16') for forming a focal zone (18) from an input laser beam (14) incident on said beam shaping device (16, 16'); and a telescope device (34, 34') for imaging said focal zone (18) into a material (72) of said workpiece (70), said beam shaping device (16, 16') extending along a central longitudinal axis (40) that is curved at least in a certain portion thereof. a telescope device (34, 34') that is assigned a beam splitting device (46) for splitting a partial beam (24) output-coupled from the beam shaping device (16, 16') into a plurality of polarized partial beams (54a, 54b), each of which has one of at least two different polarization states; and a telescope device (34, 34') with the beam splitting device (46) for splitting the polarized partial beams (54a, 54b) into a plurality of polarized partial beams (54a, 54b), each of which has one of at least two different polarization states. ) into a first partial focal zone (58a) of a first partial beam (54a) having a first polarization state and into a second partial focal zone (58b) of a second partial beam (54b) having a second polarization state, so that the focal zone (18) at least in certain parts is formed by a spatial overlap of the first partial focal zone (58a) and the second partial focal zone (58b), and the focal zone (18) has an asymmetric cross section in a plane oriented perpendicular to the longitudinal central axis (40).

1. An apparatus having a surface, characterized in that the beam splitting device (46) has a birefringent polarizing element (62) whereby both a spatial offset (Δx) and an angular offset (Δα) are created between the first partial beam (54a) and the second partial beam (54b) coupled out of the beam splitting device (46), and the first partial beam (54a) coupled out of the beam splitting device (46) is oriented parallel to the optical axis (56) of the telescope device (34, 34').

2. 2. The device according to claim 1, characterized in that the first partial focal zone (58a) extends along a first central longitudinal axis (60a) and the second partial focal zone (58b) extends along a second central longitudinal axis (60b), the first central longitudinal axis (60a) and the second central longitudinal axis (60b) each have a curved shape at least in certain parts, and the first central longitudinal axis (60a) and the second central longitudinal axis (60b) have a spatial offset (Δb) in a direction oriented perpendicular to the first central longitudinal axis (60a) and / or the second central longitudinal axis (60b).

3. 3. The apparatus according to claim 1 or 2, characterized in that the first partial beam (54a) and the second partial beam (54b) are incoherent with respect to each other and / or the first partial beam (54a) and the second partial beam (54b) do not have a fixed phase relationship with respect to each other.

4. The apparatus according to any one of claims 1 to 3, characterized in that the beam splitting device (46) is arranged in a far field region (48) of the telescope device (34, 34') and / or the beam splitting device (46) is arranged at least approximately in a focal plane (50) of the telescope device (34, 34').

5. The apparatus according to any one of claims 1 to 4, characterized in that the beam splitting device (46) is or comprises a beam splitter optical unit and / or the beam splitting device (46) has at least one birefringent element.

6. 6. The apparatus according to claim 1, wherein the beam splitting device (46) is used to split an incident beam (52) into different partial beams (54a, 54b) having different polarization states, and the partial beams (54a, 54b) outputted from the beam splitting device (46) and having different polarization states have an angular offset (Δα).

7. 7. The device according to claim 1, characterized in that the central longitudinal axis (40) of the focal zone (18), at least in certain parts, has a radius of curvature of at least 50 μm and / or at most 100 mm, and / or the central longitudinal axis (40) of the focal zone (18) has an average radius of curvature of at least 200 μm and / or at most 2 mm, and / or the focal zone (18) has a length of at least 50 μm and / or at most 20 mm.

8. Apparatus according to any one of the preceding claims, characterized in that the focal zone (18) has a quasi-non-diffractive and / or Bessel-like beam profile.

9. 9. Apparatus according to any one of claims 1 to 8, characterized in that the focal zone (18) has an elliptical cross-section in a plane oriented perpendicular to the central longitudinal axis (40) of the focal zone (18), characterized in that a maximum diameter (dx, dy) of the cross-sectional ellipse of the focal zone (18) is aligned at least approximately parallel to an advance direction (86) in which the workpiece (70) moves relative to the focal zone (18) to form a machining line (74) and / or a machining surface.

10. Apparatus according to any one of claims 1 to 9, characterized in that it comprises a laser source (12) for providing the input laser beam (14), wherein a pulsed laser beam or an ultrashort pulsed laser beam is provided by the laser source (12).

11. The arrangement according to any one of claims 1 to 10, characterized in that the phase distribution of the partial beams (24) outputted on the beam exit surface (22) of the beam shaping device (16, 16') is asymmetric and / or not rotationally symmetric.

12. A method for laser processing a workpiece (70), in which a beam shaping device (16, 16') is used to form a focal zone (18) from an input laser beam (14) incident on the beam shaping device (16, 16'), the focal zone (18) being or being capable of being imaged by a telescope device (34, 34') into a material (72) of the workpiece (70), and the beam shaping device (16, 16') is configured to shape the focal zone (18) at least in a specific portion of the workpiece (70). a beam splitting device (46) assigned to the telescope device (34, 34') is used to split a partial beam (24) outputted from the beam shaping device (16, 16') into a plurality of polarized partial beams (54a, 54b), each of which has one of at least two different polarization states, the polarized partial beams (54a, 54b) being a first partial beam (54a) having a first polarization state and a second partial beam (54b) having a second polarization state are focused into a first partial focal zone (58a) and a second partial focal zone (58b) so that the focal zone (18) in at least a certain portion is formed by a spatial overlap of the first partial focal zone (58a) and the second partial focal zone (58b), the focal zone (18) having an asymmetric cross section in a plane oriented perpendicular to the longitudinal central axis (40).

11. The method of claim 10, wherein the beam splitting device (46) comprises a birefringent polarizing element (62) which creates both a spatial offset (Δx) and an angular offset (Δα) between the first partial beam (54a) and the second partial beam (54b) coupled out of the beam splitting device (46), and wherein the first partial beam (54a) coupled out of the beam splitting device (46) is oriented parallel to the optical axis (56) of the telescope device (34, 34').

Images