Apparatus and method for laser processing of workpieces

Abstract

The invention relates to an apparatus for laser processing (104) of a workpiece having a material (102) transparent to the laser processing, comprising a first beam shaping device (106) having a beam splitting element (112) for splitting a first input beam (108) input-coupled into the first beam shaping device (106) into a plurality of sub-beams (114), and focusing optics (116) assigned to the first beam shaping device (106) and for imaging the sub-beams (114) output-coupled from the first beam shaping device (106) into at least one focal region (122), wherein the first input beam (108) is split by phase-imposing on the first input beam (108) by means of the beam splitting element (112), wherein the sub-beams (114) are focused into different partial regions (120) of the at least one focal region (122) to form the at least one focal region (122), wherein the at least one focal region (122) is introduced into the material (102) with at least one adjustment angle (α) relative to an outer side (144; 146) of the workpiece (104) by means of the focusing optics (116) for laser processing (104) of the workpiece, and wherein a material modification (156) associated with a change in the refractive index of the material (102) is produced in the material (102) by loading the material (102) by means of the at least one focal region (122).

Description

Technical Field

[0001] The present invention relates to an apparatus for laser processing of a workpiece having a material that is transparent to laser processing.

[0002] The present invention also relates to a method for laser processing of a workpiece having a material that is transparent to laser processing. Background Technology

[0003] US 2020 / 0147729 A1 discloses a method for forming a chamfered edge region on a glass substrate using a laser beam, wherein the shape of the chamfered edge region is matched by matching the axial energy distribution of the laser beam.

[0004] The purpose of this invention is to provide an apparatus and a method as described at the beginning of this document, which can be used flexibly in a variety of ways, and by means of the apparatus and the method, in particular, to enable laser processing of workpieces along different processing geometries in a technically simple manner. Summary of the Invention

[0005] In the case of the apparatus described at the beginning of this document, according to the present invention, this objective is achieved by means of an apparatus comprising a first beam shaping device and a focusing optics device, the first beam shaping device having a beam splitting element for splitting a first input beam coupled to the first beam shaping device into a plurality of sub-beams, the focusing optics device being assigned to the first beam shaping device and for imaging the sub-beams coupled from the output of the first beam shaping device into at least one focal region, wherein the first input beam is split by applying a phase to the first input beam by means of the beam splitting element, wherein these sub-beams are focused into different portions of the at least one focal region to form at least one focal region, wherein the at least one focal region is introduced into the material by means of the focusing optics at at least one adjustment angle relative to the outer side of the workpiece for laser processing, and wherein material modification associated with a change in the refractive index of the material is generated in the material by loading the material with means of the at least one focal region.

[0006] By splitting the first input beam based on phase application using a beam-splitting element and then focusing the resulting sub-beams, at least one focal region with different geometries can be formed in a technically simple manner. As a result, the at least one focal region can be formed, in particular, by different portions, each with different geometries and / or different adjustment angles. Therefore, laser processing of workpieces with different processing geometries can be achieved in a technically simple manner.

[0007] In the case of the solution according to the invention, in particular, at least one focusing area can be introduced into the material at an adjustable angle, which does not require adjusting the optics with respect to the workpiece.

[0008] In particular, material modifications associated with changes in the refractive index of a material should be understood as material modifications that are accompanied by changes in the refractive index of the material and / or when a material modification is formed, there is a change in the refractive index of the material.

[0009] In particular, the beam-splitting element is formed as a diffraction beam-splitting element and / or a 3D beam-splitting element. The beam-splitting element preferably achieves phase application on the beam cross-section of the first input beam.

[0010] In particular, the first input beam is split by means of a beam-splitting element through pure phase manipulation of the phase of the first input beam. In particular, the phase application of the first input beam achieved by means of the beam-splitting element is variablely adjustable and / or limited.

[0011] In particular, it is possible to configure at least one focus area to have multiple focus distributions and / or be formed by multiple focus distributions. For example, the focus distributions are arranged in different portions of the focus area.

[0012] The corresponding focal distributions within the focal area are arranged within the focal area, and in particular, are spaced a certain distance from each other. However, the corresponding focal distributions may at least partially overlap in space.

[0013] In particular, at least one focal area extends in a plane. The focal distribution forming at least one focal area is preferably arranged in a plane. In particular, the plane is oriented perpendicular to the feed direction in which at least one focal area moves relative to the workpiece to perform laser processing on the workpiece.

[0014] In particular, the lens component and / or grating component of the phase distribution applied by means of a beam-splitting element are assigned to each focus distribution of at least one focus area. Specifically, the applied phase distribution comprises multiple superimposed lens components and / or grating components, wherein each focus distribution of at least one focus area is assigned a lens component and / or grating component. As a result, different focus distributions with spatial offsets in the focus areas can be arranged in a plane oriented perpendicular to the feed direction, in which the focus areas move relative to the workpiece to perform laser processing on the workpiece.

[0015] For example, the first beam shaping device is configured as a far-field beam shaping element or includes one or more far-field beam shaping elements. For example, at least one focal region is formed by focusing a sub-beam coupled from the output of the first beam shaping device onto a corresponding portion of the focal region using focusing optics.

[0016] For example, focusing optics are constructed as microscope objectives or lens elements.

[0017] In one embodiment, the first beam shaping device may be configured to rotate about an axis parallel to the main propagation direction of the first input beam or about an axis parallel to the main propagation direction of the first input beam. As a result, at least one focusing area may be rotated, for example, about a rotation axis perpendicular to the feed direction orientation, in which at least one focusing area moves relative to the workpiece to perform laser processing on the workpiece.

[0018] It can be configured such that the focusing optics are integrated into the first beam shaping device and / or the focusing optics are part of the first beam shaping device and / or the function of the focusing optics is integrated into the first beam shaping device.

[0019] In particular, the workpiece is made of a material that is transparent to the laser beam that forms at least one focal area.

[0020] Transparent material should be understood in particular as material through which at least 70%, and in particular at least 80%, and in particular at least 90% of the laser energy of the laser beam forming at least one focal zone is transmitted.

[0021] In particular, the first input beam is the first input beam that is coupled to the first beam shaping device and / or beam splitting element.

[0022] In particular, the material modification produced in the material by means of at least one focal zone can be configured to be Type I and / or Type II modification. As a result, a material modification accompanying a change in the refractive index of the material is generated in the workpiece material during laser processing. In particular, material separation can be performed at these material modifications.

[0023] In one embodiment, the device includes a second beam shaping device for beam shaping a first input beam coupled to a first beam shaping device. The second beam shaping device applies a phase to a second input beam incident on the second beam shaping device to assign a focused distribution having a defined geometry and / or a defined intensity profile to the first input beam. This allows a sub-beam coupled from the output of the first beam shaping device to be focused into different regions of the focused area using focusing optics, forming focused distributions based on the geometry and / or intensity profile, respectively. This allows for matching the geometry of the focused distribution forming at least one focused area. Consequently, the device can be used flexibly and in multiple ways.

[0024] In particular, the second beam shaping device is positioned in front of the first beam shaping device relative to the main propagation direction of the laser beam guided by the device.

[0025] In particular, the second input beam is the input beam of the second beam shaping device. For example, the second input beam is a laser beam provided by the device's laser source, specifically a laser beam with a Gaussian beam profile.

[0026] In particular, the first input beam is a beam coupled from the output of the second beam shaping device and / or a beam provided by means of the second beam shaping device.

[0027] In particular, the second beam shaping device modifies and / or matches the focus distribution of the second input beam coupled to the second beam shaping device. Specifically, the focus distribution modified and / or matched by the second beam shaping device is assigned to the first input beam provided by the second beam shaping device.

[0028] In one embodiment, the second beam shaping device may be configured to rotate about an axis parallel to the main propagation direction of the second input beam or about an axis parallel to the main propagation direction of the second input beam. As a result, at least one focusing area may be rotated, for example, about a rotation axis perpendicular to the feed direction orientation, in which at least one focusing area moves relative to the workpiece to perform laser processing on the workpiece.

[0029] In particular, the phase application on the second input beam can be configured such that the focused distribution has an elongated shape with respect to the assigned main extension direction, and / or the phase application on the second input beam can be configured such that the focused distribution has a quasi-diffraction intensity profile and / or a Bessel-like intensity profile. As a result, at least one focused region can be constructed, for example, by multiple focused distributions having an elongated shape. Consequently, corresponding elongated and / or linear material modifications can be formed, resulting in, for example, improvements in the introduction of etchant liquids for material separation.

[0030] The second beam shaping device is or includes beam shaping elements, such as diffractive optical elements and / or axial taper elements, for implementing phase application, in particular.

[0031] In particular, the main extension direction of the elongated focal distribution is oriented obliquely to the feed direction and especially perpendicular to the feed direction, in which at least one focal area moves relative to the workpiece to perform laser processing on the workpiece.

[0032] Advantageously, the phase application on the second input beam can result in a focused distribution having an intensity profile with respect to the assigned principal extension direction that decreases from the maximum intensity at the intensity maximum point of the intensity profile to approximately 1 / e of the maximum intensity, much faster than in the case of a Gaussian intensity profile. 2The phase application on the second input beam, and / or the phase distribution, causes the focused distribution to have a sudden self-focused beam shape and / or intensity profile. Because the intensity of these focused distributions decreases rapidly, material processing becomes more precise, and damage to the processed material is reduced. As a result, material can be separated, especially by means of particularly flat and / or smooth edges.

[0033] For example, the strength increases from the maximum strength to 1 / e of the maximum strength. 2 The decrease is faster than that of the Gaussian intensity profile, by at least 2.5 times and / or up to 3.5 times.

[0034] In particular, starting from the maximum intensity in the main extension direction, the intensity profile has an intensity drop edge (Intensity drops) at which an intensity decrease occurs. Specifically, after the intensity drop flank, the intensity of the intensity profile in the main extension direction is less than 1 / e of the maximum intensity. 2 The value of a multiple.

[0035] Preferably, when laser processing is performed on the workpiece, the edge with reduced intensity faces the good part segment. As a result, a particularly smooth cutting edge can be achieved, especially within the range of material separation.

[0036] The aforementioned maximum intensity values ​​specifically refer to the primary maximum and / or global maximum of the intensity profile. In particular, the intensity profile has one or more secondary maximum values ​​that are adjacent to the maximum intensity values ​​in the opposite direction to the primary extension direction. Specifically, the corresponding maximum intensity of the secondary maximum decreases with increasing distance from the primary maximum.

[0037] In particular, when laser processing is performed on a workpiece, the secondary maximum value is located in the residual workpiece segment and / or the scrap segment. As a result, cracks and / or channels that promote etching for material separation can be formed in the residual workpiece segment and / or the scrap segment.

[0038] In particular, the main extension direction of these focused distributions is parallel to or approximately parallel to the main propagation direction orientation of the second input beam.

[0039] It can be configured such that the focused distribution intermediate image is formed by means of a second beam shaping device, wherein, in particular, the focused distribution intermediate image is arranged in front of the first beam shaping device with respect to the main propagation direction of the second input beam.

[0040] The second beam shaping device is specifically configured as a near-field beam shaping device, that is, in particular, the focused distribution is imaged as an intermediate image by means of the second beam shaping device.

[0041] In particular, the intermediate image formed by means of the second beam shaping device is an image representation of the focused distribution of the first input beam coupled to the first beam shaping device.

[0042] In one embodiment, the device includes a far-field optics device assigned to a second beam shaping device, wherein the far-field optics device is used to far-field focus an output beam coupled from the second beam shaping device onto the focal plane of the far-field optics device, and wherein, in particular, the first beam shaping device is arranged in the region of the focal plane.

[0043] In particular, the output beam coupled from the far-field optics then corresponds to the first input beam to be coupled into the first beam shaping device.

[0044] The region of the focal plane should be understood in particular as the region extending around the focal plane, which is at most 10% of the focal length of the far-field optics.

[0045] In particular, it can be configured to focus the intermediate image of the focused distribution formed by the second beam shaping device onto the focal plane in the far field using far-field optics.

[0046] In particular, the following can be achieved with the aid of far-field optics: the intermediate image generated by the second beam shaping device and / or the Fourier transform of the focused distribution generated by the second beam shaping device.

[0047] It can be configured such that far-field optics are integrated into the second beam shaping device and / or the far-field optics are part of the second beam shaping device and / or the function of the far-field optics is integrated into the second beam shaping device.

[0048] In particular, the transverse intensity distribution of the first input beam has a ring structure and / or a ring segment structure in the focal plane.

[0049] It can be configured such that far-field optics and focusing optics form a telescope device, and / or far-field optics and focusing optics have a common focal plane, wherein a first beam shaping device is arranged in the region of the common focal plane.

[0050] In particular, the focal length of far-field optics is greater than that of focusing optics.

[0051] In particular, it is possible to configure a focus distribution having a defined geometry and / or a defined intensity profile to be assigned to the first input beam, wherein this geometry and / or intensity profile is also assigned to a sub-beam coupled from the output of the first beam shaping device, and / or wherein focus distributions based on this geometry and / or intensity profile are formed respectively by focusing the sub-beam coupled from the output of the first beam shaping device into different portions of at least one focus region using focusing optics. As a result, at least one focus region can be constructed, in particular, by mutually spaced and / or adjacent focus distributions having defined geometries. Further, this leads, for example, to the formation of at least one focus region by connecting (Aneinanderreihung) the focus distributions to each other as approximately identical copies, based on beam splitting using a beam-splitting element.

[0052] The defined geometry and / or defined intensity profile are assigned to the first input beam, for example, by means of a laser source providing the first input beam. Alternatively, this assignment is achieved by means of the second beam shaping device described above.

[0053] In one embodiment, the first input beam incident on the beam-splitting element and / or the first beam-shaping device has a Gaussian intensity profile, for example, if it originates directly from a laser source. As a result, at least one focusing area is thus constructed and / or formed, for example, by a plurality of adjacent “foci” having a Gaussian shape and / or a Gaussian intensity profile.

[0054] Advantageously, the first beam shaping apparatus includes a beam shaping element for modifying the focused distribution allocated to the first input beam, wherein, by means of the beam shaping element, the geometry and / or intensity profile of the focused distribution imaged into at least one focused area is modified and / or oriented in a cross-sectional plane perpendicular to the feed direction in which at least one focused area moves relative to the workpiece for laser processing, and / or wherein, by means of the beam shaping element, the geometry and / or intensity profile of the focused distribution imaged into at least one focused area is modified and / or oriented in a cross-sectional plane parallel to the feed direction in which at least one focused area moves relative to the workpiece for laser processing.

[0055] In particular, the cross-sectional plane oriented parallel to the feed direction is oriented perpendicular to the main propagation direction of the beam that forms the focused distribution.

[0056] The input beam coupled to the first beam shaping device is modified by means of the beam shaping elements of the first beam shaping device, particularly within and / or by means of the first beam shaping device.

[0057] In particular, the beam shaping element is or includes a diffractive or refractive beam shaping element, and / or the beam shaping element is or includes a diffractive field mapper. In particular, the beam shaping element can be used to apply defined wavefront aberrations to an input beam coupled to the beam shaping element.

[0058] In particular, the beam shaping element is configured such that a focused distribution modified by means of the beam shaping element is distributed to the sub-beam coupled from the output of the first beam shaping device, such that by means of a focusing optics, the sub-beam coupled from the output of the first beam shaping device is focused into different regions of the focused area, forming focused distributions having the modified geometry and / or the modified intensity profile respectively.

[0059] In particular, the modified shape and / or the modified intensity distribution are based on the original shape and / or the original intensity profile assigned to the first input beam. Specifically, the modified shape and / or the modified intensity distribution should be understood as a modification based on a change in the original shape and / or the original intensity profile.

[0060] Advantageously, the orientation of the main extension direction of the geometry and / or intensity profile of the focused distribution can be adjusted, or can be adjusted, in a cross-sectional plane perpendicular to the feed direction orientation using a beam-shaping element, and, in particular, this orientation is adjusted such that the main extension direction is parallel to or approximately parallel to the corresponding local extension direction orientation of the focused area. For example, this allows for the formation of material modifications in the workpiece material that are approximately parallel to the local extension direction orientation of the focused area. In particular, this achieves optimized material separation.

[0061] The orientation of the main extension direction of the geometry and / or intensity profile of the focused distribution can also be configured such that the main extension direction is oriented obliquely to the corresponding local extension direction. For example, the main extension direction includes a minimum angle of at least 1° and / or at most 90° with the local extension direction. As a result, the focused distribution is at least partially located in, for example, residual workpiece segments and / or scrap segments generated during laser processing of the workpiece. As a result, for example, material modifications and / or channels that facilitate etch etching for material separation are formed in the residual workpiece segments and / or scrap segments.

[0062] As a matter of principle, the focus distribution in a cross-sectional plane oriented perpendicular to the feed direction can also be modified by means of a beam shaping element, such that the focus distribution has a main extension direction in the cross-sectional plane perpendicular to the feed direction.

[0063] It is possible to modify the focus distribution in a cross-sectional plane oriented perpendicular to the feed direction by means of a beam shaping element, such that the focus distribution has a curved longitudinal central axis.

[0064] Advantageously, this modification of the intensity profile, achieved by means of a beam-shaping element in a cross-sectional plane oriented parallel to the feed direction, results in the intensity profile having at least one preferred direction, wherein, in particular, at least one preferred direction is oriented parallel to, or oblique to, or perpendicular to the feed direction. As a result, in particular, the formation of material modifications in the workpiece material during laser processing can be controlled and / or optimized. For example, this enables the improvement of the introduction of etching fluid for material separation purposes.

[0065] In particular, at least one preferred direction and the feed direction are located in a common plane.

[0066] For example, the intensity profile of the focused distribution can be formed, for example, elliptical or rectangular or square, in a plane parallel to the feed direction using a beam shaping element.

[0067] For example, the semi-major axis of an ellipse should be understood as the preferred direction of a focused distribution constructed as an ellipse.

[0068] For example, the preferred orientation of the focal distribution, which is constructed as an ellipse, is parallel to or approximately parallel to the feed direction.

[0069] The focus distribution, constructed as a square or rectangle, has, for example, two preferred directions, each parallel to the orientation of the connecting direction between two opposite points of the square. For instance, one preferred direction is parallel to the feed direction, while the other is perpendicular to the feed direction.

[0070] Advantageously, the orientation of the focused distribution in at least one preferred direction in a cross-sectional plane parallel to the feed direction orientation can be adjusted or adjusted by means of a beam-shaping element of the first beam-shaping device. As a result, in particular, the formation of material modifications in the workpiece material during laser processing can be controlled and / or optimized.

[0071] In particular, at least one adjustment angle of at least one focus area can be set to at least 1° and / or at most 90°. Preferably, at least one adjustment angle is at least 10°.

[0072] The adjustment angle should be understood, in particular, as the minimum angle between the local extension direction assigned to at least one focal area and the outer side of the workpiece. For example, at least one focal area is input-coupled and / or introduced into the material of the workpiece through this outer side.

[0073] It can be configured such that at least one focus area has different parts, and these different parts have different local extension directions and / or adjustment angles.

[0074] Advantageously, the first beam shaping device includes a polarization beam splitter configured such that sub-beams coupled from the output of the first beam shaping device each have one of at least two different polarization states, wherein the sub-beams with different polarization states are focused into adjacent partial regions of at least one focal region by means of a focusing optics. As a result, at least one focal region can be formed by connecting the focal points and / or focal distributions with different polarization states to each other.

[0075] Focal points and / or focal distributions with different polarization states are formed, in particular, by mutually incoherent sub-beams. As a result, focal points and / or focal distributions can be arranged at very small distances from each other and / or connected to each other.

[0076] A polarization beam splitter is used, in particular, to split an input beam coupled to the polarization beam splitter into multiple polarimetric sub-beams, each of which has at least one of two different polarization states.

[0077] For example, polarization beam-splitting elements include birefringent wedge elements and / or birefringent lens elements. This allows for directional and / or angular shifts in sub-beams with different polarization states before focusing them using focusing optics. As a result, sub-beams with different polarization states can be imaged into at least one spatially different portion of the focal region.

[0078] In particular, different polarization states should be understood as different linear polarization states.

[0079] For example, polarization beam splitter elements include quartz crystals used for polarization beam splitting purposes.

[0080] According to the present invention, the method described at the beginning of this document specifies that a beam-splitting element of a first beam-shaping device is used to split a first input beam incident on the beam-splitting element into a plurality of sub-beams, and the sub-beams coupled from the output of the first beam-shaping device are focused into at least one focal region by means of a focusing optics assigned to the first beam-shaping device, wherein the first input beam is split by means of the beam-splitting element by applying a phase to the first input beam, wherein the sub-beams are focused into different portions of the at least one focal region to form at least one focal region, wherein the at least one focal region is introduced into the material by means of the focusing optics at at least one adjustment angle relative to the outside of the workpiece for laser processing of the workpiece, and wherein a material modification associated with a change in the refractive index of the material is generated in the material by means of loading the material with means of the at least one focal region.

[0081] The method according to the invention, in particular, has one or more features and / or advantages of the device according to the invention.

[0082] In particular, the method according to the invention can be implemented using a device according to the invention. Specifically, the device according to the invention performs the method according to the invention.

[0083] In particular, at least one focal area can be configured to move relative to the workpiece material in the feed direction to perform laser processing on the workpiece. Specifically, the relative speed of orientation between the material and at least one focal area in the feed direction is set or adjustable.

[0084] In particular, it can be configured to form material modification in the workpiece material along the machining line and / or machining surface by relative movement of at least one focal area relative to the workpiece. Specifically, the result can be separation of the workpiece along the machining line and / or machining surface.

[0085] Advantageously, the material of a workpiece can be separated along the machining lines and / or the machined surface by applying thermal loads and / or mechanical stress and / or by etching with the aid of at least one wet chemical solution. For example, etching is performed in an ultrasonic-assisted etching bath.

[0086] In particular, the device according to the invention and / or the method according to the invention have one or more of the following features: It can be configured such that at least one focal area extends between two different and / or opposite outer sides of the workpiece, and particularly extends continuously. For example, these outer sides are oriented parallel to or oblique to each other. For example, this can result in the workpiece being separated into two distinct segments, or segments being separated from the workpiece for edge processing purposes. As a result, for example, edge areas can be beveled or chamfered.

[0087] In particular, at least one focal region can be configured with a focal distribution arranged in such a way that material modification is formed in the scrap and / or residual workpiece segments to be separated from the workpiece. For example, the material modification forms channels for improving the introduction of etching fluid for material separation.

[0088] For example, the focused distribution of at least one focused area is arranged such that these are at least partially disposed within residual workpiece segments and / or scrap segments formed during laser processing of the workpiece, or at least partially protrude into residual workpiece segments formed during laser processing of the workpiece. For example, this can result in the formation of material modifications and / or channels within the residual workpiece segments and / or scrap segments, which facilitate the supply of etching liquid to the material modifications formed during laser processing. This enables improved material separation along the processed surface where the material modifications are disposed.

[0089] For the same reason, it may be advantageous to arrange the focus distribution of at least one focus area such that the main maximum value and / or global maximum value of the corresponding focus distribution face the good part segment generated during laser processing of the workpiece, and / or away from the residual workpiece segment.

[0090] For example, a good part segment should be understood as a useful segment generated during the separation of workpieces (compared to residual workpiece segments and / or scrap segments).

[0091] In particular, the formation of the focal zone and the focal distribution of the focal zone have intensity fluctuations of no more than 20%.

[0092] In particular, the device includes a workpiece mount for the workpiece, which preferably has a non-reflective and / or strongly scattering surface.

[0093] In particular, the device can be configured to have a laser source for providing a laser beam, which can form, or create, at least one focused area. Specifically, the laser source can provide a pulsed laser beam and / or an ultrashort pulse laser beam.

[0094] In particular, at least one focusing region is formed by or provided by an ultrashort pulse laser beam. This ultrashort pulse laser beam specifically comprises ultrashort laser pulses.

[0095] For example, the wavelength of the laser beam that can form or form at least one focal region is at least 300 nm and / or no more than 1500 nm. For example, the wavelength is 515 nm or 1030 nm.

[0096] In particular, the laser beam that can form or form at least one focused area has an average power of at least 1 W to 1 kW. For example, the laser beam comprises pulses with pulse energies of at least 10 µJ and / or at most 50 mJ. It can be configured that the laser beam comprises individual pulses or pulse trains, wherein the pulse trains have 2 to 20 sub-pulses and, in particular, time intervals of about 20 ns.

[0097] It can be configured such that at least one focal area can rotate about a rotation axis perpendicular to the feed direction, and in this feed direction, at least one focal area moves relative to the workpiece to perform laser processing on the workpiece. As a result, the workpiece can be processed, for example, along curved processing lines and / or processing surfaces.

[0098] In particular, at least one focal zone forms a spatially continuous interaction region for laser processing of the workpiece, wherein local material modifications that achieve material separation can be formed, particularly by loading the workpiece material through the interaction region. Specifically, crack formation and / or changes in the refractive index of the material exist between adjacent material modifications.

[0099] Material modification introduced into transparent materials via ultrashort laser pulses can be subdivided into three distinct categories; see K. Itoh et al., “Ultrafast Processes for Bulk Modification of Transparent Materials,” MRS Bulletin, Vol. 31, p. 620 (2006): Type I is isotropic refractive index variation; Type II is birefringent refractive index variation; and Type III is so-called voids or cavities. In this respect, the resulting material modification depends on the laser parameters of the laser beam forming the focal region (e.g., pulse duration, wavelength, pulse energy, and repetition frequency of the laser beam), as well as on material properties (e.g., electronic structure and coefficient of thermal expansion), and also on the numerical aperture (NA) of the focal point.

[0100] Through rapid re-solidification of the transparent material using laser pulses, the type I isotropic refractive index change can be traced back to locally confined fusion. For example, if quartz glass is cooled more rapidly from a higher temperature, it has a higher material density and refractive index. Therefore, if the material in the focused volume melts and is subsequently cooled rapidly, the quartz glass has a higher refractive index in the material-modified region than in the unmodified region.

[0101] Type II birefringence refractive index changes can occur, for example, due to interference between an ultrashort laser pulse and the electric field of the plasma generated by the laser pulse. This interference leads to periodic modulation in the electron plasma density, which results in birefringence properties of transparent materials during curing, i.e., direction-dependent refractive index. Type II modifications are also accompanied, for example, by the formation of so-called nanogratings.

[0102] For example, type III modified voids (cavities) can be generated at high laser pulse energies. In this case, void formation is attributed to the explosive expansion of highly excited evaporating material from the focusing volume into the surrounding material. This process is also known as micro-explosion. Because this expansion occurs within the material mass, micro-explosions result in less dense or hollow (void) microscopic defects, or submicron or atomic-level defects, which are encapsulated by a dense material. Considering the compaction at the impact front of the micro-explosion, stresses are generated in transparent materials that may lead to spontaneous crack formation or may promote crack formation.

[0103] In particular, void formation can also accompany Type I and Type II modifications. For example, Type I and Type II modifications can occur in smaller stress regions around the introduced laser pulse. Correspondingly, if we refer to the introduction of Type III modification, there is always a less dense, hollow, or defective structure. For example, micro-explosions in sapphire through Type III modification do not create cavities, but rather regions of lower density. Due to the material stress generated in the case of Type III modification, this modification is also usually accompanied by or at least promotes crack formation. When Type III modification is introduced, the formation of Type I and Type II modifications cannot be completely suppressed or avoided. Therefore, it is unlikely to find "pure" Type III modification.

[0104] At high laser beam repetition rates, materials cannot cool completely between pulses, allowing the cumulative effect of heat introduced from pulse to pulse to potentially modify the material. For example, the laser beam repetition frequency may be higher than the reciprocal of the material's thermal diffusion time, causing heat accumulation due to continuous absorption of laser energy to occur in the focal region until the material's melting temperature is reached. Furthermore, due to heat transfer to areas surrounding the focal region, regions larger than the focal region can fuse. The heated material cools rapidly after the introduction of the ultrashort laser pulse, and thus the density and other structural properties of the high-temperature state are frozen within the material.

[0105] At least one focal region comprises, in particular, a plurality of spaced-apart and / or adjacent focal distributions, wherein the focal region may have interruptions and / or zeros between adjacent focal distributions, at which, in particular, there is no interaction with the material or there is negligible interaction. In particular, these interruptions of the focal region have a spatial extension not exceeding 10% of the maximum extension and / or maximum length of the focal region. In particular, these interruptions have a spatial extension not exceeding 100 µm and, especially, not exceeding 50 µm. If there are interruptions with relatively large intensity distributions, then this should be understood as referring to different focal regions.

[0106] For example, at least one focal region has a total length between 50 µm and 5000 µm.

[0107] To determine the spatial dimensions (e.g., the corresponding length and / or the corresponding diameter) of at least one focal region, the focal region is considered in a modified intensity distribution that includes only intensity values ​​above a specific intensity threshold. In this respect, for example, the intensity threshold is chosen such that values ​​below it have such low intensity that they are no longer relevant to the material used to form the material modification. For example, the intensity threshold is 50% of the global maximum intensity of the actual intensity distribution. The length or diameter of the corresponding focal region should then be understood as, based on the modified intensity distribution, the maximum extension length and / or the maximum extension of the corresponding focal region along its longitudinal central axis or in a plane oriented perpendicular to the longitudinal central axis.

[0108] In particular, the indications “at least about” and “about” should generally be understood to mean a deviation of no more than 10%. Unless otherwise stated, the indications “at least about” or “about” should be understood to specifically mean that the actual value and / or distance and / or angle deviates from the ideal value and / or distance and / or angle by no more than 10%, and / or the actual geometry deviates from the ideal geometry by no more than 10%. Attached Figure Description

[0109] The following description of preferred embodiments is provided to explain the invention in more detail with reference to the accompanying drawings. In the attached diagram: Figure 1 A schematic diagram of an embodiment of an apparatus for laser processing of a workpiece is shown; Figure 2 A schematic diagram of another embodiment of an apparatus for laser processing of a workpiece is shown; Figure 3a A schematic cross-sectional view of an embodiment of the focus distribution of the focus area for laser processing of a workpiece is shown; Figure 3b A schematic cross-sectional view of another embodiment of the focus distribution of the focus area for laser processing of a workpiece is shown; Figure 3c A schematic cross-sectional view of another embodiment of the focus distribution of the focus area for laser processing of a workpiece is shown; Figure 4a A schematic cross-sectional view of a portion of an example of a focal zone introduced into the material of a workpiece is shown; Figure 4b A schematic cross-sectional view showing a portion of another example of a focal zone introduced into the material of a workpiece; Figure 5 A schematic cross-sectional view of the focal zone that completely penetrates the workpiece from the first outer side to the second outer side is shown; Figure 6A schematic cross-sectional view is shown of material modifications produced in the material of a workpiece by means of a focusing area, wherein these material modifications are accompanied by the formation of cracks in the material; Figure 7 A schematic cross-sectional view is shown of material modifications produced in the material of a workpiece by means of a focal zone, wherein these material modifications are produced by means of thermal accumulation and / or accompanied by changes in the refractive index in the material; Figure 8 A cross-sectional view of the simulated intensity distribution of an example of a focal region with multiple spaced-apart elongated focal distributions is shown. Figure 9a A cross-sectional view of the simulated intensity distribution of an example of a suddenly self-focusing laser beam is shown; Figure 9b It shows according to Figure 9a The intensity distribution of a suddenly self-focusing laser beam along its main extension direction; Figure 10 A cross-sectional view of the simulated intensity distribution in the focal region is shown, which has multiple mutually spaced focal distributions constructed as a sudden self-focusing beam; Figure 11 A schematic diagram of the phase distribution assigned to the suddenly self-focusing beam is shown; Figure 12 a, Figure 12 c. Figure 12 e shows cross-sectional views of the simulated intensity distribution in the focal region for three different embodiments. Figure 12 b、 Figure 12 d、 Figure 12 f respectively shows the assignments according to Figure 12 a, Figure 12 c and Figure 12 A schematic diagram of the phase distribution of the cross-section of e; Figure 13a A schematic perspective view showing the material modification produced in the workpiece material along the machining lines and / or machined surfaces; and Figure 13b A schematic diagram of two sections of a workpiece is shown, which are formed by separating the workpiece at the machining line and / or machining surface.

[0110] In all embodiments, elements that are identical or have equivalent functions are represented by the same reference numerals. Detailed Implementation

[0111] Examples of equipment for laser processing of workpieces are described in Figure 1As shown in the figure, and indicated by 100 in that figure, the device 100 can be used to produce localized material modifications in the material 102 of the workpiece 104, such as weakening submicron or atomic-level defects in the material. At these material modifications, the workpiece can, for example, be separated into different segments, or the segments can, for example, be separated from the workpiece 104 in a subsequent step. In particular, the device 100 can be used to introduce the material modification into the material 102 at a certain adjustment angle, such that, due to the separation of the corresponding segments from the workpiece 104, the edge regions of the workpiece 104 can be beveled or chamfered.

[0112] The device 100 includes a first beam shaping device 106 to which a first input beam 108 is input coupled. For example, the first input beam 108 is, for instance, a laser beam provided by and / or output coupled from a laser source 110. In particular, the first input beam 108 should be understood to refer to a beam comprising a plurality of rays, particularly those traveling in parallel.

[0113] The laser beam provided by the laser source 110 is, in particular, a pulsed laser beam and / or an ultrashort pulse laser beam.

[0114] The first beam shaping device 106 includes a beam splitting element 112, by means of which the first input beam 108 is split into a plurality of sub-beams 114 and / or component beams. Figure 1 In the example shown, two distinct sub-beams, 114a and 114b, are indicated.

[0115] For example, the first beam shaping device 106 and / or the beam splitting element 112 are each configured as far-field beam shaping elements.

[0116] To focus the sub-beam 114 coupled from the output of the first beam shaping device 106, the device 100 includes a focusing optics 116 to which the sub-beam 114 is input coupled. For example, different sub-beams 114 are incident on the focusing optics 116 with spatial and / or angular offsets.

[0117] For example, the focusing optics 116 is configured as a microscope objective or lens element.

[0118] The sub-beam 114 is focused into different portions 120 of the focal region 122 by means of a focusing optics 116, and these portions are introduced into the material 102 of the workpiece 104 for laser processing.

[0119] For example, Figure 1Two distinct partial regions 120a and 120b are designated, and the sub-beam 114 is focused into these two distinct partial regions to form a focused region 122. Here, for example, partial region 120a is assigned to sub-beam 114a, and partial region 120b is assigned to sub-beam 114b.

[0120] A specific focus distribution is assigned to the first input beam 108 that is input to the first beam shaping device 106. This focus distribution should be understood as referring to the geometry and / or intensity profile that will be formed by focusing the first input beam 108 before it is input to the first beam shaping device 106.

[0121] For example, the first input beam 108 provided by means of laser source 110 has a Gaussian beam profile. Focusing the first input beam 108 before input coupling to the first beam shaping device 106 will result in a focused distribution having a Gaussian shape and / or Gaussian intensity profile in this case.

[0122] In particular, the shape of the focused distribution should be understood as referring to the unique spatial shape and / or spatial extension of the focused distribution.

[0123] The first input beam 108, coupled to the first beam shaping device 106, is split by the beam splitting element 112 in such a way that the focused distribution is also allocated to the sub-beams 114. These sub-beams 114 are focused into different portions 120 of the focusing region 122 by means of the focusing optics 116 to form corresponding focused distributions 124, which are based on the focused distribution allocated to the first input beam 108.

[0124] As a result, a focal region 122 is constructed and / or formed by connecting different focus distributions 124 to each other. Currently, different focus distributions 124 should be understood as focus distributions 124 at different spatial locations within the focal region 122, wherein these different focus distributions 124 have at least approximately the same geometry and / or the same geometric intensity profile.

[0125] Different focal distributions 124 are arranged at a certain distance from each other in the focal area 122. In principle, adjacent different focal distributions 124 can overlap in space.

[0126] The beam splitting by the beam splitting element 112 makes the focused distribution form identical copies, which are imaged in different portions of region 120 of the focused region 122.

[0127] For example, beam splitter 112 is constructed as a 3D beam splitter. For the technical implementation and characteristics of beam splitter 112, refer to the scientific publication “Structured light for ultrafast laser micro-and nanoprocessing” by D. Flamm et al., arXiv:2012.10119v1 [Physics. Optics], December 18, 2020. See the full text.

[0128] In particular, the distance d1 and / or spatial offset between adjacent focus distributions 124 can be set by means of the beam splitting element 112.

[0129] For example, a distance dx and / or spatial offset in the x-direction and a distance dz and / or spatial offset in the z-direction perpendicular to the x-direction orientation can be set between adjacent focus distributions 124.

[0130] For this purpose, distinct sub-beams 114 are formed, for example by means of a beam-splitting element 112, in such a way that the distinct sub-beams are incident on the focusing optics 116 with specific spatial offsets and / or specific convergence and / or divergence. The distinct sub-beams 114 are then imaged by means of the focusing optics 116 with the resulting spatial offsets in the x and / or z directions.

[0131] To perform beam splitting using the beam splitter element 112, a defined lateral phase distribution is applied to the lateral beam cross-section of the first input beam 108. For example, Figure 12 a, Figure 12 b and Figure 12 c. Figure 12 d and Figure 12 e Figure 12 Examples of the lateral phase distribution of the beam coupled from the output of the beam splitter 112 and the associated focusing region 122 are shown in f.

[0132] To generate spatial offsets in the x and / or z directions, phase application via beam-splitting element 112 is implemented, for example, in such a manner that the phase distribution assigned to each focusing distribution 124 has a specific grating component and / or optical lens component. Due to the grating component, there is an angular deflection of sub-beams 114 upstream of focusing optics 116, which, upon focusing, results in a spatial offset in the x direction. Due to the optical lens component, sub-beams 114 are incident on focusing optics 116 with different convergence and / or divergence, which, upon focusing, results in a spatial offset in the z direction.

[0133] The first beam shaping device 106 may be configured to have a polarization beam splitter element 126. The polarization beam splitter element 126 performs polarization beam splitting on the first input beam 108 and / or the beam coupled from the output of the beam splitter element 112, splitting them into beams each having one of at least two different polarization states.

[0134] By means of polarization beam splitting element 126, the sub-beams 114 coupled from the first beam shaping device 106 each have one of at least two different polarization states. These sub-beams 114 with different polarization states are focused into different regions 120 of the focusing region 122 by means of focusing optics 116.

[0135] For example, the polarization beam splitter 126 is arranged in front of or behind the beam splitter 112 relative to the main propagation direction 128 of the first input beam 108 coupled to the first beam shaping device 106.

[0136] In the example shown, the main propagation direction 128 is oriented parallel to or approximately parallel to the z-direction. In particular, the x-direction and z-direction are each oriented perpendicular to the y-direction. In the example shown, this y-direction is oriented parallel to or approximately parallel to the feed direction 129, in which the focus distribution 124 moves relative to the workpiece 104 to perform laser processing on the workpiece 104.

[0137] Regarding the function and implementation of the polarization beam splitter 126, reference is made to German patent applications by the same applicant, No. 10 2020 207 715.0 (filed June 22, 2020) and No. 10 2019 217 577.5 (filed November 14, 2019), neither of which were previously published. The entire contents of both are explicitly referenced.

[0138] In particular, the polarization state of the sub-beam 114 should be understood as a linear polarization state, wherein, for example, two different polarization states are provided and / or the corresponding polarization directions of the sub-beams, for example, are oriented relative to each other at an angle of 90°.

[0139] In particular, the sub-beam 114 is polarized in such a way that the electric field is oriented in a plane perpendicular to the propagation direction of the sub-beam (transverse electric field).

[0140] For polarization beam splitting, the polarization beam splitter element 126 has, for example, a birefringent lens element and / or a birefringent wedge element. For example, the birefringent lens element and / or the birefringent wedge element are made of or comprise quartz crystal.

[0141] For example, sub-beams 114 with different polarization states are formed in such a way as by means of birefringent lens elements that the sub-beams are spatially offset in the z and / or x directions due to focusing by means of focusing optics 116. As a result, the focused distribution 124 formed by the sub-beams 114 with different polarization states can be arranged, for example, in the focused region 122 with spatial offset in the z and / or x directions.

[0142] For example, the focus distributions 124 can be interconnected in the focus region 122 by means of the polarization beam splitter 126, wherein each adjacent focus distribution 124 is formed by a sub-beam 114 with a different polarization state.

[0143] Furthermore, the first beam shaping device 106 may be configured to have a beam shaping element 130, by means of which the focused distribution allocated to the first input beam 108 is modifiable after its input is coupled into the first beam shaping device 106.

[0144] For the technical implementation and characteristics of the beam shaping element 130, refer to the scientific publication "Structured light for ultrafast laser micro- and nanoprocessing" by D. Flamm et al., arXiv:2012.10119v1 [Physics. Optics], December 18, 2020, and the book "Laser Beam Shaping: Theory and Techniques," edited by Fred M. Dickey, CRC Press, 2014. Please refer to the full text of these publications.

[0145] For example, beam shaping element 130 is configured as a diffraction or refraction phase element for applying defined wavefront aberrations to a beam coupled into beam shaping element 130. For example, beam shaping element 130 is configured as a diffraction field mapper.

[0146] For example, the beam shaping element 130 is arranged in front of or behind the beam splitting element 112 relative to the main propagation direction 128 of the first input beam 108.

[0147] exist Figure 1 In the example shown, the beam shaping element 130 is arranged between the beam splitter element 112 and the polarization beam splitter element 126. For example, the first input beam 108 is first processed by the beam splitter element 112, and then by the beam shaping element 130 and / or the polarization beam splitter element 126.

[0148] The beam shaping element 130 can modify the geometry and / or intensity profile of the focus distribution 124 imaged into the focus region 122.

[0149] The beam shaping element 130 allows modification of the focus distribution 124 of the focusing region 122 in a cross-sectional plane parallel to the feed direction 129, wherein this cross-sectional plane is perpendicular to the main propagation direction 128 and / or particularly perpendicular to the z-direction. Figure 3a , Figure 3b and Figure 3c )orientation.

[0150] Furthermore, beam shaping element 130 can be used as a means to further enhance this effect. Figure 4a and Figure 4b The focus distribution 124 of the focus region 122 is modified in a cross-sectional plane perpendicular to the feed direction 129. In the example shown, this cross-sectional plane is parallel to the x-direction and oriented parallel to the main propagation direction 128 and / or the z-direction.

[0151] Regarding the cross-sectional plane oriented parallel to the feed direction 129, the focus distribution 124 is modified, for example, in such a way that the shape and / or intensity profile of the focus distribution 124 has a preferred orientation 132 in that cross-sectional plane. In particular, this preferred orientation 132 should be understood as the direction in which the extension length of the focus distribution 124 is locally or globally maximized. For example, the preferred orientation 132 should be understood as the main extension direction of the focus distribution 124.

[0152] exist Figure 3b In the example shown, the focus distribution 124 is elliptical in shape and / or formed as an ellipse in a plane parallel to the feed direction 129. In this case, the preferred orientation is that the direction 132 is parallel to the major semi-axis of the ellipse.

[0153] In principle, the focused distribution 124 can also have multiple preferred directions 132. Figure 3c In the example shown, the focus distribution 124 is formed as a rectangle and / or as a rectangle, and especially as a square, in a plane parallel to the feed direction 129. In this case, the focus distribution 124 has a first preferred direction 132'a and a second preferred direction 132'b, the first preferred direction being oriented, for example, parallel to the x-direction, and the second preferred direction being oriented, for example, obliquely to the x-direction, and especially perpendicular to the x-direction (that is, parallel to the y-direction in the example shown).

[0154] For example, the first preferred direction 132'a and the second preferred direction 132'b are each parallel to the connecting line between the opposite corners of the rectangle.

[0155] The focusing distribution 124 assigned to the first input beam 108 can be configured to have an elongated and / or stretched shape in a cross-sectional plane oriented perpendicular to the feed direction 129. Figure 4a and Figure 4b For example, this is achieved by assigning a quasi-non-diffractive beam profile and / or a Bezier-like beam profile to a first input beam 108 that is input to a first beam shaping device 106.

[0156] For example, the focus distribution 124 has a main extension direction 134 along which the focus distribution 124 has a particularly large length and / or particularly large extension in a cross-sectional plane perpendicular to the feed direction 129 (see also...). Figure 3c For example, the main extension direction 134 is parallel to the orientation of the connecting line between the start and end points of the maximum extension direction of the focus distribution 124.

[0157] In particular, the beam shaping element 130 can be configured to match the orientation 136 and / or orientation of the focus distribution 124 in a cross-sectional plane perpendicular to the feed direction 129, wherein, for example, the orientation 136 of the corresponding main extension direction 134 of the focus distribution 124 is matchable.

[0158] exist Figure 4a and Figure 4b In the example shown, the orientation 136 of the corresponding focus distribution 124 is matchable in the xz plane.

[0159] For example, the beam shaping element 130 is used to match the corresponding orientation 136 of the focus distribution 124 in such a way that the orientation 136 is parallel to or approximately parallel to the orientation of the local extension direction 138 of the focus region 122 assigned to the corresponding focus distribution 124.

[0160] For example, the local extension direction 138 of the focal region 122 should be understood as the local spacing direction of adjacent focal distributions 124 (e.g., two or three adjacent focal distributions 124). For example, the focal distributions 124 of the focal region 122 can be arranged in different portions of the focal region 122 with different local extension directions 138.

[0161] In a cross-sectional plane oriented perpendicular to the feed direction 129, the focus distribution 124 can be configured with a curved shape, for example, by means of a matching beam shaping element 130. Figure 4b For example, this allows the focus distribution 124 to be produced as a curved Bezier-like beam and / or an accelerated Bezier-like beam.

[0162] Regarding the formation and properties of quasi-non-diffractive beams and / or Bessel-like beams with curved shapes, refer to the scientific publication “Bessel-like optical beams with arbitrary trajectoryories” by I. Chremmos et al., Optics Letters, Vol. 37, No. 23, December 1, 2012.

[0163] For example, the focus distribution 124 has a longitudinal central axis 140 along which the focus distribution extends. For example, the longitudinal central axis 140 is constructed in a straight line. Figure 4a In the case of a focused distribution with a curved shape, the longitudinal central axis 140 has a curved or partially curved shape. Figure 4b ).

[0164] The focus distribution 124 assigned to the focus area 122 is arranged along, for example, a longitudinal axis 142 constructed in a straight line along the focus area 122 by means of the first beam shaping device 106. Figure 4a and Figure 4b ).

[0165] The longitudinal axis 142 need not be constructed in a straight line and / or continuously. For example, the longitudinal axis 142 may be at least partially curved. The longitudinal axis 142 may also have changes in direction, and in particular discontinuous changes in direction.

[0166] exist Figure 5 In the example shown, the focal region 122 extends within the material 102 of the workpiece 104 from a first outer side 144 to a second outer side 146 of the workpiece 104, wherein the second outer side 146 is spaced apart from the first outer side 144 with respect to the depth direction 148 of the workpiece 104. In particular, the focal region 122 passes through the workpiece 104 throughout the depth direction 148 and / or passes through the workpiece without interruption in the depth direction.

[0167] For example, the first outer side 144 and the second outer side 146 of the workpiece 104 are oriented parallel or approximately parallel to each other.

[0168] For example, in order to perform laser processing on workpiece 104, the focusing area 122 is introduced and / or input coupled to the material 102 of workpiece 104 via a first outer side 144 or via a second outer side 146.

[0169] The focusing region 122 has a first portion 150 starting from a first outer side 144, and a second portion 152 of the focusing region 122 is adjacent to the first portion in the depth direction 148. Further, the focusing region 122 has a third portion 154 that follows the second portion 152 in the depth direction 148.

[0170] In the example shown, the longitudinal axis 142 of the focal region 122 is constructed linearly in each of the portions 150, 152 and 154, wherein the longitudinal axis 142 has a change of direction, particularly at the transitions from the first portion 150 to the second portion 152 and from the second portion 152 to the third portion 154.

[0171] Each of these portions 150, 152 and 154 is assigned a different local extension direction 138, with the focused distribution 124 arranged in that local extension direction.

[0172] Furthermore, a specific adjustment angle α is assigned to each of the portions 150, 152, and 154. This adjustment angle α should be understood as the minimum angle between the local extension direction 138 of the corresponding portion 150, 152, and 154 and the first outer side 144 and / or the second outer side 146.

[0173] For example, the first part 150 and the third part 154 have an adjustment angle α of 45°, and the second part 152 has an adjustment angle α of 90°.

[0174] The material 102 of the workpiece 104 is made of a material that is transparent to the wavelength of the laser beam that forms the focal region 122 and / or the focal distribution 124.

[0175] To laser process material 102, a focusing region 122 is introduced into material 102. By loading material 102 with the focusing region 122 in this way, a corresponding local material modification 156 is formed at the focusing distribution 124. Figure 6 These material modifications are arranged, for example, at a distance from each other along the longitudinal axis 142 of the focal region 122.

[0176] By appropriately selecting processing parameters (such as laser parameters and / or advance speed), material modification 156 can be modified into a Type III modification, which leads to the spontaneous formation of crack 157 in material 102. Figure 6 In particular, cracks 157 formed during the laser processing of material 102 extend between adjacent material modifications 156.

[0177] The forward speed should be understood as the speed of the relative motion between the focal zone 122 and the material 102 in the feed direction 129.

[0178] As an alternative, appropriate selection of processing parameters enables the material modification 156 to be produced as a type I and / or type II modification, which is accompanied by heat accumulation in the material 102 and / or a change in the refractive index of the material 102.

[0179] The material modification 156 is configured as a Type I and / or Type II modification in association with heat accumulation in the material 102 of the workpiece 104. In particular, in this case, the resulting material modifications 156 are so closely connected that such heat accumulation (e.g., during the formation of these material modifications by loading the material 102 with the aid of the focusing region 122) occurs. Figure 7 (As shown).

[0180] In one embodiment, the device 100 includes a second beam shaping device 158, which is arranged in front of the first beam shaping device 106 with respect to the main propagation direction 128 of the first input beam 108 input coupled into the first beam shaping device 106. With the aid of the second beam shaping device 158, the focusing distribution assigned to the first input beam can be matched before the first input beam 108 is input coupled into the first beam shaping device 106.

[0181] In this embodiment, in particular, a second input beam 160 provided by the laser source 110 and / or coupled to the output of the laser beam from the laser source 110 is input coupled to the second beam shaping device 158.

[0182] Therefore, similar to the first input beam 108, the second input beam 160 should be understood in particular to refer to a beam that includes, in particular, multiple rays traveling in parallel.

[0183] In the example shown, the first input beam 108, which is input coupled to the first beam shaping device 106, is a beam coupled from the second beam shaping device 158 and / or a beam coupled from the second beam shaping device 158.

[0184] Phase is applied to the second input beam 160 using the second beam shaping device 158, thereby defining the focused distribution assigned to the first input beam 108 input to the first beam shaping device 106. As a result, the geometry and / or intensity profile of the focused distribution assigned to the first input beam 108 can be defined by means of the second beam shaping device 158.

[0185] For example, the second input beam 160, which is input coupled to the second beam shaping device 158, has a Gaussian beam profile, that is, the second input beam 160 has a Gaussian shape and / or a Gaussian intensity profile.

[0186] In one embodiment, the second beam shaping device 158 is configured and designed such that, by means of the second beam shaping device 158, a quasi-non-diffractive beam profile and / or a Bezier-like beam profile are assigned to a first input beam 108 that is input coupled to the first beam shaping device 106.

[0187] As a result, the first input beam 108 can be imaged, in particular, into a focused distribution having a quasi-non-diffractive beam profile and / or a Bessel-like beam profile. In this embodiment, the focused distribution 124 imaged into the focused region 122 has an elongated shape and / or an elongated intensity profile. Figure 2 and Figure 8 In particular, the focus distribution 124 of this embodiment has a main extension direction 162 along which the focus distribution extends.

[0188] For example, the second beam shaping device 158 is or includes diffractive optical elements and / or axial tapered elements for applying a phase distribution to the second input beam 160 to form a focused distribution 124 having an elongated shape and / or an elongated intensity profile.

[0189] In this embodiment, a first input beam 108 provided by a second beam shaping device 158 is input-coupled into a first beam shaping device 106. As described above, the first input beam 108 is split into distinct sub-beams 114 by a beam-splitting element 112 of the first beam shaping device 106, and the distinct sub-beams are imaged into different portions 120 of a focal region 122 by a focusing optics device 116. Regarding its shape and / or intensity profile, the focus distribution 124 imaged into the focal region 122 by the focusing optics device 116 represents a copy of the focus distribution assigned to the first input beam 108, wherein focusing by the focusing optics device 116 specifically achieves imaging with a reduced size of the focus distribution 124.

[0190] An example of a focused distribution 124 having an elongated shape and / or elongated intensity profile imaged into a focused region 122 by means of a focusing optics 116 is shown in [the following text is incomplete and likely refers to a separate example]. Figure 8 The value is depicted as a distribution of gray values, where brighter gray values ​​represent greater intensity.

[0191] exist Figure 8 In the example shown, the focus distribution 124 is oriented obliquely to the longitudinal axis 142 and / or the local extension direction 138.

[0192] As described above, it can be configured such that beam shaping is performed in the first beam shaping device 106 by means of beam shaping element 130 and / or beam splitting is performed by means of polarization beam splitting element 126. In this case, the focus distribution 124 imaged by means of focusing optics 116 is based in shape and / or its intensity profile on the focus distribution assigned to the first input beam 108, but has a modified shape and / or modified polarization characteristics relative to the focus distribution assigned to the first input beam 108 due to the processing by means of beam shaping element 130 and / or polarization beam splitting element 126.

[0193] In another embodiment, the second beam shaping device 158 is configured and constructed such that, by means of the second beam shaping device 158, the first input beam 108 input coupled to the first beam shaping device 106 is assigned a beam profile whose intensity profile starts from a maximum intensity 164 and abruptly decreases in intensity with respect to the main extension direction 166 and / or the main extension axis. Figure 9a and Figure 9b For example, this type of beam is called a sudden self-focusing beam.

[0194] As a result, a focal region 122 can be formed by multiple focal distributions 124 having such intensity profiles by imaging the sub-beam 114 coupled from the output of the first beam shaping device 106. Figure 10 In particular, the intensity profile of each of the focus distributions 124 in the focus region 122 suddenly decreases in intensity.

[0195] Figure 11 The image depicts a grayscale representation of the associated two-dimensional phase distribution of the beam coupled from the output of the second beam shaping device 158, wherein the assigned grayscale scale ranges from white (+pi phase) to black (-pi phase).

[0196] In particular, the phase distribution is configured to be radially and / or rotationally symmetrical with respect to the assigned central axis 167 and / or the beam central axis. For example, the central axis 167 is oriented parallel to or approximately parallel to the main propagation direction 267 of the second input beam 160 incident on the second beam shaping device 158.

[0197] In particular, starting from the central axis 167, the phase frequency assigned to the phase distribution increases in the radial direction 367 as the radial distance from the central axis 167 increases.

[0198] In this embodiment, the shape and / or intensity profile of the abruptly autofocusing beam is assigned to the first input beam 108, which is input to the first beam shaping device 106. For information on the formation and characteristics of such a beam, see the scientific publications “Abruptly autofocusing waves” by Efremidis, Nikolaos K., and Demetrios N. Christodoulides, Optics Letters 35.23 (2010): 4045-4047, and “Observation of abruptly autofocusing waves” by Papazoglou et al., Optics Letters 36.10 (2011): 1842-1844. The entire contents of these publications are explicitly referenced.

[0199] exist Figure 9a and Figure 9b In the embodiment shown, when starting from the maximum intensity 164, the focused distribution 124 has an intensity decreasing edge 165 in the main extension direction 166.

[0200] The characteristic of a suddenly self-focusing beam is that, compared to the case of a Gaussian intensity profile, the intensity decreases to 1 / e much faster at the intensity drop-off edge of 165, starting from the maximum intensity of 164. 2 The value is approximately three times the speed of the Gaussian intensity profile.

[0201] The maximum intensity 164 is specifically the primary and / or global maximum intensity profile of the suddenly self-focusing beam. In particular, the intensity profile has one or more secondary maximum values ​​164a, which begin with the maximum intensity 164 and follow it in the opposite direction to the primary extension direction 166. Specifically, each of the secondary maximum values ​​164 has a lower maximum intensity value as the distance from the maximum intensity 164 with respect to the primary extension direction 166 increases.

[0202] In particular, the second beam shaping device 158 can be configured as a near-field beam shaping device.

[0203] For example, an intermediate image 168 of the focused distribution allocated to the first input beam 108 is formed by means of the second beam shaping device 158. Figure 2 (Indicated in the middle). Regarding the main propagation direction 128 of the first input beam 108, the intermediate image 168 is arranged between the second beam shaping device 158 and the first beam shaping device 106.

[0204] In particular, the second beam shaping device 158 is equipped with a far-field optics 170, by means of which the output beam 172 and / or the output beam coupled from the second beam shaping device 158 are far-field focused into the focal plane 174 of the far-field optics 170.

[0205] In particular, far-field focusing of the intermediate image 168 onto the focal plane 174 is achieved by means of the far-field optics 170.

[0206] In this focal plane 174, the far-field focusing of the output beam 172 and / or the output ray beam results in an intensity distribution having a ring structure and / or a ring segment structure shape, particularly arranged around the optical axis 176 of the far-field optics 170.

[0207] exist Figure 2In the example shown, the telescope assembly 178 of device 100 is formed by means of a far-field optics 170 and a focusing optics 116. For this purpose, the far-field optics 170 has a larger focal length than the focusing optics 116.

[0208] In particular, focal plane 174 is the common focal plane of far-field optics 170 and focusing optics 116. In particular, focal plane 174 is the focal plane of telescope assembly 178.

[0209] The first beam shaping device 106 is particularly arranged in and / or in a region of the focal plane 174. This region should be understood as the area extending around the focal plane 174, which, for example, has a maximum distance from the focal plane 174 of 10% of the focal length of the far-field optics 170. The spacing direction of this maximum distance is particularly parallel to the optical axis 176 and / or the main propagation direction 128 of the first input beam 108.

[0210] The aforementioned region of focal plane 174 should be understood in particular as the far-field region of telescope device 178, in which the far-field focusing of the output beam 172 coupled from the output of the second beam shaping device 158 and / or the first input beam 108 to be input coupled to the first beam shaping device 106 is particularly present.

[0211] With the help of the beam splitting element 112 of the device 100, the focus distribution 124 can be arranged along different paths in principle, thus forming focus areas with different geometries.

[0212] exist Figure 12 a and Figure 12 In the example shown in b, the focus distribution 124 is arranged along the longitudinal axis 142 of the focus area 122, wherein the longitudinal axis 142 is constructed in a straight line. In this case, a single adjustment angle α is assigned to the focus area 122, for example, by means of which the focus area 122 is angled relative to the first outer side 144 and / or the second outer side 146. In particular, the focus area 122 in this embodiment always has the same local extension direction 138, that is, the local extension direction 138 is constant, especially over the entire extension of the focus area 122.

[0213] According to Figure 12 c and Figure 12 In embodiment d, the focusing region 122 has a first portion 180 and a second portion 182, wherein the focusing distribution 124 of the focusing region 122 is arranged in the first portion 180 and the second portion 182 with different local extension directions 138. For example, in this embodiment, the focusing region 122 always has the same local extension direction 138 in the first portion 180 and the second portion 182.

[0214] In particular, the focusing region 122 has the same adjustment angle α in the first portion 180 and the second portion 182, and the focusing region 122 forms the adjustment angle with respect to the first outer side 144 and / or the second outer side 146. In particular, in this case, the minimum angle between the corresponding local extension directions 138 of the first portion 180 and the second portion 182 is twice the adjustment angle α.

[0215] The longitudinal axis 142 of the focusing area 122 (along which the focusing distribution 124 is arranged) does not need to be constructed as a straight line. For example, the longitudinal axis 142 may be configured to have at least a partially curved shape. Figure 12 e and Figure 12 In the example shown in f, the focal region 122 has a curved shape overall.

[0216] For example, the focal region 122 thus has a varying local extension direction 138, that is, the local extension direction 138 of the focal region 122 is different at different locations of the focal region 122 and / or at different focal distributions 124 of the focal region 122.

[0217] Figure 12 b、 Figure 12 d and Figure 12 f respectively shows the assignments to Figure 12 a, Figure 12 c and Figure 12 The phase distribution of the beam coupled from the output of beam splitter 112, wherein the assigned grayscale scale ranges from white (+pi phase) to black (-pi phase).

[0218] The device 100 according to the present invention operates as follows: In order to perform laser processing, the material 102 of the workpiece 104 is loaded by means of the focusing area 122, and the focusing area 122 moves relative to the workpiece 104 and passes through the material 102 of the workpiece in the feed direction 129.

[0219] In this case, material 102 is in particular a material that is transparent or partially transparent to the wavelength of the beam that forms the focusing region 122. For example, material 102 is a glass material.

[0220] For example, the focus area 122 moves along a predetermined machining line 184 and / or machining surface through the material 102 of the workpiece 104. The machining line 184 may, for example, have straight and / or curved portions.

[0221] By loading material 102 with the aid of focal region 122, material modification 156 is formed in material 102 arranged along the longitudinal axis 142 of focal region 122. Figure 5 and Figure 13aAs a result, modification lines 186 are formed in the material, with material modifications 156 arranged along these modification lines, wherein these modification lines 186 have, in particular, a shape corresponding to the longitudinal axis 142 of the focal region 122. Figure 13a In the example shown, the modification line 186 extends from the first outer side 144 to the second outer side 146.

[0222] Due to the relative movement of the focal region 122 with respect to the material 102, multiple modification lines 186 are formed, spaced apart from each other and parallel to the feed direction 129. In particular, this results in a planar structure of material modification 156 in the material 102. Figure 13a ).

[0223] For example, the spacing between adjacent modification lines 186 in the feed direction 129 can be limited by appropriate selection of the pulse duration of the laser beam forming the focal region 122 and / or the forward speed oriented in the feed direction 129.

[0224] In particular, the material modification 156 formed along the machining line 184 and / or the machined surface thus reduces the strength of the material 102. This makes it possible, for example by applying mechanical force, to separate the material 102 into two distinct segments 188a and 188b after the material modification 156 has been formed along the machining line 184 and / or the machined surface. Figure 13b ).

[0225] In the example shown, segment 188b is a good part segment with the desired edge shape. In this case, segment 188a is a residual workpiece segment and / or a scrap segment.

[0226] Preferably, the material 102 is loaded via the focusing region 122 in such a manner that the focusing region 122 penetrates the material 102. For example, the focusing region 122 extends continuously and / or uninterruptedly through the material 102 over its entire thickness D. For example, as... Figure 13a and Figure 13b As shown, the result is that the material can be completely separated at its thickness D.

[0227] The edge region 190 of the material 102 can also be processed using the focusing area 122. Figure 13a (As indicated in the text). For example, the focal area 122 then extends continuously and / or uninterruptedly between the outer sides of the workpiece 104, which are oriented obliquely to each other. For example, as a result, the edge segment can be separated from the workpiece 104 in the edge region 190. As a result, the workpiece 104 can be beveled or chamfered, for example, in the edge region 190.

[0228] For example, the material 102 of workpiece 104 is quartz glass. For example, to form the material modification 156 as a Type I and / or Type II modification, the laser beam forming the focused distribution 124 of the focused region 122 then has a wavelength of 1030 nm and a pulse duration of 1 ps. Further, the numerical aperture assigned to the focusing optics 116 is then 0.4, and the pulse energy assigned to a single focused distribution 124 is then 100 nJ.

[0229] In order to form the material modification 156 as a Type III modification with other parameters remaining unchanged, the pulse energy allocated to the single focused distribution 124 is 1000 nJ.

[0230] List of reference numerals α Adjustment angle D Thickness d1 Distance Distance in the x-direction dx Distance in the z direction dz 100 devices 102 Materials 104 workpieces 106 First Beam Shaping Device 108 First Input Beam 110 laser source 112 beam splitter elements 114 beamlets 114a sub-beam 114b sub-beam 116 Focusing Optics 120 Partial Area 120a Partial Area 120b Partial Area 122 Focus Area 124-Focused Distribution 126 Polarization beam splitter element 128 Main Communication Direction 129 Feed direction 130 beam shaping element 132 Preferred Direction 132'a First preferred direction 132'b Second preferred direction 134 Main extension direction 136 Orientation 138 Local extension direction 140 Longitudinal center axis 142 Longitudinal axis 144 First outer side 146 Second outer side 148 Depth Direction 150 Part 1 152 Part Two 154 Part Three 156 Material Revision 157 Cracks 158 Second Beam Shaping Device 160 Second Input Beam 162 Main extension direction 164 Maximum Intensity 164a second maximum value 165 Intensity drop edge 166 Main extension direction 167 Central Axis 267 Main Communication Direction 367 Radial direction 168 Intermediate Image 170 Far-field optical devices 172 Output Beam 174 Focal plane 176 optical axes 178 Telescope device 180 Part One 182 Part Two 184 processing line 186 Modified Line Section 188a Section 188b 190 Edge Area

Claims

1. An apparatus for laser processing of a workpiece (104) having a material (102) transparent to the laser processing, the apparatus comprising a first beam shaping device (106) and a focusing optics device (116), the first beam shaping device having a beam splitting element (112) for splitting a first input beam (108) coupled into the first beam shaping device (106) into a plurality of sub-beams (114), the focusing optics being assigned to the first beam shaping device (106) and for imaging the sub-beams (114) coupled from the output of the first beam shaping device (106) into at least one focusing region (122), wherein, The first input beam (108) is split by applying a phase to the first input beam (108) using the beam splitting element (112), wherein the sub-beams (114) are focused into different portions (120) of the at least one focusing region (122) to form the at least one focusing region (122), wherein, in order to perform laser processing on the workpiece (104), the at least one focusing region (122) is introduced into the material (102) with at least one adjustment angle (α) relative to the outer side (144; 146) of the workpiece (104) by means of the focusing optics (116), such that the different portions (120) each have different geometries and / or different adjustment angles, and wherein, by loading the material (102) with means of the at least one focusing region (122), a material modification (156) associated with a change in the refractive index of the material (102) is generated in the material (102).

2. The device according to claim 1, characterized in that, The material modification (156) produced in the material (102) by means of the at least one focal region (122) is a type I modification and / or a type II modification.

3. The device according to claim 1 or 2, characterized in that... It also includes a second beam shaping device (158) for beam shaping the first input beam (108) input to the first beam shaping device (106), wherein the second beam shaping device (158) applies a phase to the second input beam (160) incident on the second beam shaping device (158) to distribute a focused distribution having a defined geometry and / or a defined intensity profile to the first input beam (108), such that the sub-beam (114) output from the first beam shaping device (106) is focused into different portions (120) of the focused region (122) by means of the focusing optics (116), forming focused distributions (124) based on the geometry and / or the intensity profile, respectively.

4. The device according to claim 3, characterized in that, The phase application on the second input beam (160) is such that the focusing distribution (124) has an elongated shape with respect to the assigned main extension direction, and / or the phase application on the second input beam (160) is such that the focusing distribution (124) has a quasi-non-diffractive intensity profile and / or a Bessel-like intensity profile.

5. The device according to claim 3, characterized in that, The phase application on the second input beam (160) is such that the focused distribution (124) has an intensity profile about the assigned principal extension direction, which, compared to the case of a Gaussian intensity profile, decreases more rapidly from the maximum intensity at the maximum intensity value (164) of the intensity profile to 1 / e of the maximum intensity. 2 The velocity is approximately three times that of the case of a Gaussian intensity profile, and / or the phase application on the second input beam (160) is such that the focus distribution (124) has a sudden self-focusing beam shape and / or intensity profile.

6. The device according to claim 3, characterized in that, The intermediate image (168) of the focused distribution (124) is formed by means of the second beam shaping device (158), and the intermediate image (168) of the focused distribution (124) is arranged in front of the first beam shaping device (106) with respect to the main propagation direction (267) of the second input beam (160).

7. The device according to claim 3, characterized in that... A far-field optics (170) is assigned to the second beam shaping device (158), wherein the output beam (172) coupled from the second beam shaping device (158) is far-field focused into the focal plane (174) of the far-field optics (170) by means of the far-field optics (170), and the first beam shaping device (106) is arranged in the region of the focal plane (174).

8. The device according to claim 7, characterized in that, The intermediate image (168) of the focus distribution (124) formed by the second beam shaping device (158) is far-field focused onto the focal plane (174) by means of the far-field optical device (170).

9. The device according to claim 7 or 8, characterized in that, The far-field optics (170) and the focusing optics (116) form a telescope device (178), and / or the far-field optics (170) and the focusing optics (116) have a common focal plane (174), wherein the first beam shaping device (106) is arranged in the region of the common focal plane (174).

10. The device according to any one of claims 1, 2, 4 to 8, characterized in that, The first input beam (108) is assigned a focused distribution having a defined geometry and / or a defined intensity profile, wherein the same geometry and / or intensity profile are assigned to the sub-beam (114) coupled from the output of the first beam shaping device (106), and / or wherein the focused distribution (124) is formed based on the geometry and / or the intensity profile by means of the focusing optics (116) focusing the sub-beam (114) coupled from the output of the first beam shaping device (106) into different portions (120) of the focused region (122).

11. The device according to claim 10, characterized in that, The first beam shaping device (106) includes a beam shaping element (130) for modifying the focus distribution allocated to the first input beam (108), wherein, by means of the beam shaping element (130), the geometry and / or intensity profile of the focus distribution (124) imaged onto the at least one focus area (122) is modified and / or oriented in a cross-sectional plane perpendicular to the feed direction (129), wherein the at least one focus area (122) is relative to The workpiece (104) is moved to perform laser processing on the workpiece (104), and / or wherein, by means of the beam shaping element (130), the geometry and / or intensity profile of the focus distribution (124) imaged onto the at least one focus area (122) is modified and / or oriented in a cross-sectional plane parallel to the feed direction (129), wherein the at least one focus area (122) is moved relative to the workpiece (104) to perform laser processing on the workpiece (104).

12. The device according to claim 11, characterized in that, The orientation (136) of the main extension direction of the geometry and / or intensity profile of the focused distribution (124) can be adjusted or modified in a cross-sectional plane perpendicular to the orientation of the feed direction (129) by means of the beam shaping element (130), and the orientation (136) is adjusted such that the main extension direction is parallel or approximately parallel to the orientation of the corresponding local extension direction (138) of the focused region (122).

13. The device according to claim 11 or 12, characterized in that, With the aid of the beam shaping element (130), the intensity profile of the focused distribution (124) is modified in a cross-sectional plane oriented parallel to the feed direction (129) such that the intensity profile has at least one preferred direction (132), wherein the at least one preferred direction (132) is oriented parallel to the feed direction (129), or oblique to the feed direction, or perpendicular to the feed direction.

14. The device according to any one of claims 1, 2, 4 to 8, 11, and 12, characterized in that, The first beam shaping device (106) has a polarization beam splitter (126) configured such that the sub-beams (114) coupled from the first beam shaping device (106) each have one of at least two different polarization states, wherein the sub-beams (114) with different polarization states are focused by means of the focusing optics (116) into an adjacent portion region (120) of the at least one focusing region (122).

15. A method for laser processing a workpiece (104), the workpiece having a material (102) transparent to the laser processing, wherein, A first input beam (108) coupled to the first beam shaping device (106) is split into multiple sub-beams (114) by means of a beam-splitting element (112). The sub-beams (114) coupled from the output of the first beam shaping device (106) are focused into at least one focal region (122) by means of a focusing optics (116) assigned to the first beam shaping device (106). The first input beam (108) is split by means of a phase application to the first input beam (108) by means of the beam-splitting element (112), and the sub-beams (114) are focused into the at least one focal region (122). In different regions (120) of the workpiece (104), at least one focal region (122) is formed, wherein the at least one focal region (122) is introduced into the material (102) at at least one adjustment angle (α) relative to the outer side (144; 146) of the workpiece (104) by means of the focusing optics (116), such that the different regions (120) each have different geometries and / or different adjustment angles for laser processing of the workpiece (104), wherein material modification (156) associated with the refractive index change of the material (102) is generated in the material (102) by loading the material (102) by means of the at least one focal region (122).

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