EP4347171A1 - Procédé et appareil pour le traitement au laser d'une pièce à travailler - Google Patents

Procédé et appareil pour le traitement au laser d'une pièce à travailler

Info

Publication number
EP4347171A1
EP4347171A1 EP22730767.5A EP22730767A EP4347171A1 EP 4347171 A1 EP4347171 A1 EP 4347171A1 EP 22730767 A EP22730767 A EP 22730767A EP 4347171 A1 EP4347171 A1 EP 4347171A1
Authority
EP
European Patent Office
Prior art keywords
focal zone
preferred direction
section
workpiece
cross
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22730767.5A
Other languages
German (de)
English (en)
Inventor
Jonas Kleiner
Tim Hesse
Daniel FLAMM
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Trumpf Laser und Systemtechnik GmbH
Original Assignee
Trumpf Laser und Systemtechnik GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE102021123801.3A external-priority patent/DE102021123801A1/de
Application filed by Trumpf Laser und Systemtechnik GmbH filed Critical Trumpf Laser und Systemtechnik GmbH
Publication of EP4347171A1 publication Critical patent/EP4347171A1/fr
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
    • B23K26/0648—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising lenses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
    • B23K26/0652—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising prisms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/04—Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
    • B23K26/046—Automatically focusing the laser beam
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/067—Dividing the beam into multiple beams, e.g. multifocusing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/073—Shaping the laser spot
    • B23K26/0736—Shaping the laser spot into an oval shape, e.g. elliptic shape
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/50—Working by transmitting the laser beam through or within the workpiece
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/50—Working by transmitting the laser beam through or within the workpiece
    • B23K26/53—Working by transmitting the laser beam through or within the workpiece for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/50—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
    • B23K2103/54—Glass

Definitions

  • the invention relates to a device for laser processing a workpiece using a focus zone, the workpiece having a transparent material.
  • the invention further relates to a method for laser processing a workpiece by means of a focus zone, the workpiece having a transparent material.
  • EP 3 311 947 B1 discloses a method for laser processing a transparent workpiece such as a glass substrate, the workpiece being processed using a pulsed laser beam which has an elongated focal zone with a non-axisymmetric beam cross section.
  • DE 10 2020 103 884 A1 discloses a device for adjusting the processing optics of a laser processing machine.
  • DE 10 2019 128 362 B3 provides a diffractive optical beam-shaping element for impressing a phase distribution on a transverse beam profile of a laser beam.
  • Processing optics for workpiece processing are known from WO 2020/212175 A1, comprising a birefringent polarizer element for dividing at least one input laser beam into a pair of partial beams polarized perpendicularly to one another, and focusing optics arranged in the beam path after the polarizer element for focusing the partial beams focus zones.
  • the invention is based on the object of providing a device mentioned at the outset and a method mentioned at the outset, by means of which the formation of material modifications in the material of the workpiece is improved can be controlled in order in particular to realize a separation of the material with a smoother separation surface.
  • the device comprises a beam-shaping device for forming the focus zone from an input laser beam, the focus zone being elongate with respect to a longitudinal axis and the focus zone having an asymmetrical cross-section perpendicular to the longitudinal axis with a preferred direction, an adjusting device for changing the preferred direction during the laser processing of the workpiece, and a control device for activating the adjusting device on the basis of a predetermined assignment rule in order to control and/or regulate the preferred direction during the laser processing of the workpiece.
  • the focus zone is introduced into the material of the workpiece and is moved relative to the material.
  • material modifications are formed along a processing surface on which the material of the workpiece can in particular be separated.
  • the preferred direction of the cross section of the focal zone is correlated with a preferred direction of a cross section of material modifications that are formed in the material of the workpiece by means of the focal zone.
  • the preferred direction of the material modifications formed can be controlled by means of a provided control and/or regulation of the preferred direction of the focal zone.
  • the material modifications can be arranged and designed in such a way that the workpiece can be separated with the smoothest possible separating surface.
  • the preferred direction of the focus zone can be used to control a preferred direction of material modifications that can be formed in the material by means of the focus zone, with a main direction of extension of cracks being able to be controlled in particular, which are associated with the respective material modifications.
  • automated control and/or regulation of the preferred direction is provided by means of the control device.
  • the preferred direction of the asymmetrical cross section can be controlled over an angular range between 0° and 360°.
  • the assignment specification includes an assignment that allows the asymmetrical cross section to be controlled in an angular range between 0° and 360°.
  • the preferred direction of the asymmetrical cross section can be controlled with an angle interval of approximately 1/10° and/or in approximately 1/10° increments.
  • the focal zone forms a spatially coherent interaction area which is brought into interaction with the material in order to form material modifications in the material of the workpiece.
  • the focal zone means a focused radiation area and in particular a spatially connected radiation area of a laser beam with a specific spatial extent.
  • the intensity threshold is selected here, for example, in such a way that values lying below this intensity threshold have such a low intensity that they are no longer relevant for an interaction with the material for the formation of material modifications.
  • the intensity threshold is 50% of a global maximum intensity of the focal zone.
  • the focal zone has a total length of between 50 pm and 5000 pm.
  • the beam shaping device is set up to form the focal zone from the input laser beam in an elongated manner and with an asymmetrical cross section, the asymmetrical cross section having a preferred direction.
  • the fact that the focal zone is elongate means in particular that the focal zone extends in the direction of its longitudinal axis and/or that the focal zone is elongated and/or linear in the direction of the longitudinal axis. In particular, the focal zone has the greatest spatial extent in the direction of the longitudinal axis.
  • the longitudinal axis of the focal zone is in particular oriented parallel to a main propagation direction of a laser beam from which the focal zone is formed.
  • the longitudinal axis of the focal zone can be curved and/or designed as a curve and/or straight.
  • the workpiece is, for example, plate-shaped and/or panel-shaped.
  • the longitudinal axis of the focal zone is oriented parallel or transverse to a thickness direction of the workpiece.
  • a cross-sectional plane of the asymmetric cross-section of the focal zone is oriented perpendicular to the longitudinal axis of the focal zone.
  • the preferred direction of the asymmetrical cross section of the focal zone is to be understood in particular as a direction in which the cross section has the greatest spatial extent and/or the greatest diameter.
  • the cross section of the focal zone is at least approximately designed as an ellipse, with the preferred direction of the cross section corresponding to a direction of a major semi-axis of the ellipse.
  • the assignment specification on the basis of which the actuating device is controlled by the control device during the laser processing of the workpiece, is or includes, for example, an assignment table and/or a mathematical function.
  • the assignment rule can, for example, also be or include a constant (offset value). It can be favorable if the control device is set up to align the preferred direction during laser processing at least approximately parallel to a feed direction in which the focus zone for laser processing of the workpiece is moved relative to the workpiece.
  • cracks in the material of the workpiece associated with the formation of material modifications can be aligned at least approximately parallel to the feed direction. This results in particular in an overlapping of cracks in adjacent material modifications, which in particular enables a material separation with a smooth separation surface.
  • control device is set up to automatically align the preferred direction during the laser processing of the workpiece.
  • the focal zone has a quasi-non-diffractive and/or Bessel-like beam profile.
  • the focus zone is in particular elongate.
  • a transverse phase imprint on a beam cross section of the input laser beam takes place by means of the beam shaping device.
  • the beam-shaping device has at least one beam-shaping element for the phase imposition of a transverse phase distribution on a beam cross-section of the input laser beam, the phase distribution being selected in order to make the focal zone elongate, and the at least one beam-shaping element being used in particular as a diffractive optical element and/or is designed as an axicon element.
  • the phase distribution is selected in order to form the focal zone with a quasi-non-diffracting and/or Bessel-like beam profile.
  • a transverse direction lies in a plane oriented perpendicularly to the beam axis and/or main propagation direction of the input laser beam.
  • the phase distribution is selected in such a way that the focus zone is formed with an asymmetrical cross section by impressing the phase distribution by means of the at least one beam-shaping element.
  • the focal zone can be formed oblong and with an asymmetrical cross-section, for example, with the same element of the device.
  • a rotation of the at least one beam-shaping element then causes, in particular, a change in the preferred direction of the asymmetrical cross section.
  • an impressed phase distribution comprises a plurality of angle segments, with mutually adjacent angle segments having different azimuthal segment widths and/or a segment lattice phase difference.
  • the at least one beam-shaping element can be influenced by the adjustment device to change the preferred direction of the focal zone, and/or if the at least one beam-shaping element can be rotated by the adjustment device to change the preferred direction of the asymmetrical cross-section of the focal zone.
  • the preferred direction can be changed and/or set in a technically simple manner.
  • the at least one beam-shaping element can be rotated about an axis to change the preferred direction of the asymmetrical cross section, which is parallel or identical to the main propagation direction and/or to the beam axis of the input laser beam incident on the beam-shaping element.
  • the beam-shaping device has a polarization beam-splitting element, by means of which partial beams are formed with at least two polarization states that differ from one another, with the focal zone having an asymmetrical by focusing the partial beams Cross section is formed.
  • this allows the asymmetrical cross section of the focus zone to be formed based on the principle of polarization beam splitting.
  • the polarization states are linear polarization states.
  • partial beams with polarization states oriented perpendicularly to one another are formed by means of the polarization beam splitting element.
  • the polarization beam splitting element is designed to generate an angular offset and/or a spatial offset between the partial beams with different polarization states.
  • the polarization beam splitting element is arranged in particular in a far field area and/or in a focal plane of the beam shaping device.
  • a far-field intensity distribution is formed in this far-field region and/or in this focal plane, which is focused to form the focal zone by means of focusing optics of the beam-shaping device.
  • a rotation of the polarization beam splitting element causes in particular a change in the preferred direction of the asymmetrical cross section of the focal zone.
  • the polarization beam splitting element can be influenced by the adjustment device to change the preferred direction of the focus zone, and/or if the polarization beam splitting element can be rotated by the adjustment device to change the preferred direction of the asymmetrical cross section of the focus zone.
  • the at least one polarization beam splitting element can be rotated about an axis to change the preferred direction of the asymmetrical cross section, which is parallel or identical to the main propagation direction and/or to the beam axis of a laser beam incident on the polarization beam splitting element.
  • the beam-shaping device has a beam diaphragm to form the asymmetric cross-section of the focal zone, by means of which an angular range of a far-field intensity distribution formed by means of the beam-shaping device is blocked, with an unblocked portion of the far-field intensity distribution being used to form the elongated focal zone with an asymmetric cross-section is focused.
  • focusing optics of the beam-shaping device are provided for focusing the unblocked portion of the far-field intensity distribution.
  • a rotation of the beam diaphragm causes a change in the unblocked portion of the far-field intensity distribution and/or a change in the preferred direction of the asymmetrical cross section of the focal zone.
  • the beam diaphragm is arranged in a far field area and/or in a focal plane of the beam shaping device.
  • the beam diaphragm can be influenced by means of the adjusting device to change the preferred direction of the asymmetrical cross section of the focal zone, in which case in particular an angular range of the far-field intensity distribution that is blocked and/or not blocked by the beam diaphragm can be changed by means of the adjusting device. Changing the blocked and/or unblocked angular range of the far-field intensity distribution causes a change in the preferred direction of the asymmetrical cross-section in particular.
  • the beam stop can be rotated about an axis that is parallel or identical to the main propagation direction and/or to the beam axis of a laser beam incident on the beam stop. In this way, in particular, a change in the preferred direction of the asymmetrical cross section of the focal zone can be brought about.
  • a far-field intensity distribution is formed by means of the beam-shaping device, with the focus zone being formed by focusing the far-field intensity distribution and with the for forming the focus zone focused far field intensity distribution can be influenced by means of the adjusting device in order to change the preferred direction of the asymmetrical cross section of the focus zone.
  • the far-field intensity distribution can be influenced, for example, as described above, by means of a beam-shaping element and/or a beam diaphragm of the beam-shaping device.
  • the far-field intensity distribution is arranged in a far-field region assigned to the beam-shaping device.
  • the far-field intensity distribution includes, in particular, a ring structure and/or ring segment structure, which preferably has one or more concentric ring segments.
  • the ring segments each have the same radius.
  • the ring segments are arranged and/or formed concentrically with respect to a beam axis of a laser beam guided through the beam shaping device.
  • those angular regions of the ring structure that are focused to form the focal zone can be influenced and/or defined by means of the adjusting device.
  • the beam-shaping device includes focusing optics and/or a telescopic device in order to form the focal zone and/or to introduce the focal zone into the material of the workpiece.
  • the far-field intensity distribution for forming the focal zone can be focused by means of the focusing optics.
  • a laser beam decoupled from a beam-shaping element of the beam-shaping device can be focused by means of the telescopic device to form the focus zone.
  • the device comprises a laser source for providing the input laser beam, wherein the input laser beam provided by the laser source is in particular a pulsed laser beam and/or an ultra-short pulsed laser beam.
  • the device is designed to form the focal zone from the input laser beam and/or from an ultra-short pulse laser beam.
  • the focal zone is formed from an ultra-short pulse laser beam or is provided by means of an ultra-short pulse laser beam.
  • a wavelength of the input laser beam and/or of the laser beam from which the focus zone is formed is at least 300 nm and/or at most 1500 nm.
  • the wavelength is 515 nm or 1030 nm.
  • the input laser beam and/or the laser beam from which the focal zone is formed has an average power of at least IW to 1 kW.
  • the laser beam includes pulses with a pulse energy of at least 10 pJ and/or at most 50 mJ. It can be provided that the laser beam comprises individual pulses or bursts, the bursts having 2 to 20 sub-pulses and in particular a time interval of approximately 20 ns.
  • the workpiece is formed from a transparent material means in particular that the material of the workpiece is made from a material that is transparent to the input laser beam and/or to a laser beam from which the focal zone is formed.
  • a transparent material is to be understood in particular as a material through which at least 70% and in particular at least 80% and in particular at least 90% of a laser energy of a laser beam from which the focal zone is formed is transmitted.
  • the focal zone interacts with the material of the workpiece through non-linear absorption.
  • material modifications are formed in the material by means of the focal zone due to non-linear absorption.
  • the focus zone is set up to produce material modifications in the material of the workpiece, which with a cracking in the material of the workpiece and/or which are Type III modifications.
  • Type I is an isotropic refractive index change
  • Type II is a birefringent refractive index change
  • Type III is a so-called void.
  • the material modification produced depends on the laser parameters of the laser beam from which the focal zone is formed, such as the pulse duration, the wavelength, the pulse energy and the repetition frequency of the laser beam, and on the material properties, such as the electronic structure and the thermal expansion coefficient, as well as on the numerical aperture (NA) of focusing.
  • NA numerical aperture
  • the voids (cavities) of the type III modifications can be generated with a high laser pulse energy, for example.
  • the formation of the voids is attributed to an explosive expansion of highly excited, vaporized material from the focus volume into the surrounding material. This process is also known as a micro-explosion. Because this expansion occurs within the bulk of the material, the microblast leaves behind a less dense or hollow core (the void), or submicron or atomic-scale microscopic defect, surrounded by a densified shell of material. Due to the compression at the impact front of the microexplosion, stresses arise in the transparent material, which can lead to spontaneous cracking or can promote cracking.
  • the device comprises a detection device for optically detecting an actual preferred direction of the asymmetrical cross section of the focal zone formed, the detection device being or being able to be connected in particular to the control device in a signal-effective manner.
  • the assignment rule can be determined by means of this detection device, on the basis of which the control device activates the actuating device for controlling and/or regulating the preferred direction.
  • the detection device is set up for optical detection of the cross section of the focus zone formed and/or if the detection device is set up for optical detection of a respective cross section of material modifications produced in the material by impingement of the material of the workpiece with the focus zone.
  • an actual preferred direction of the cross section of the focal zone formed can be determined as a function of different control signals with which the control device controls the actuating device.
  • control device provision can be made for the control device to include a database and/or for the control device to be assigned a database in which the assignment rule is stored.
  • control device includes a memory device and/or the control device is assigned a memory device in which the database with the assignment specification is stored.
  • the invention provides that the focal zone is formed from an input laser beam by means of a beam shaping device, the focal zone being elongated with respect to a longitudinal axis and the focal zone having an asymmetrical cross section perpendicular to the longitudinal axis with a preferred direction, the preferred direction during the Laser processing of the workpiece is changed or can be changed by means of an adjusting device, and the preferred direction is controlled and/or regulated during laser processing of the workpiece by means of a control device, the control device controlling the adjusting device on the basis of a predetermined assignment rule.
  • the method according to the invention has in particular one or more features and/or advantages of the device according to the invention.
  • Advantageous embodiments of the method according to the invention have already been explained in connection with the device according to the invention.
  • the method according to the invention can be carried out using the device according to the invention or the method according to the invention is carried out using the device according to the invention.
  • the material of the workpiece is acted upon by the focus zone and the focus zone is moved in a feed direction relative to the material.
  • material modifications are formed, which are arranged in the material along a processing surface.
  • the focal zone and/or the processing area extend over the entire thickness of the material.
  • the focus zone is coupled into the material through an outside of the workpiece, with the focus zone in particular being oriented transversely and in particular perpendicularly to this outside.
  • the material of the workpiece can be separated or is separated after laser processing has taken place, in particular by applying thermal stress and/or mechanical stress and/or by etching using at least one wet-chemical solution.
  • the etching takes place in an ultrasonically assisted etching bath.
  • the workpiece is separated in particular at the material modifications formed and/or at the processing surface.
  • the preferred direction is aligned at least approximately parallel to a feed direction by means of the control device during the laser processing of the workpiece, in which the focal zone for the laser processing of the workpiece is moved relative to the workpiece.
  • the actual preferred direction is to be understood in particular as a resultant preferred direction and/or an actual preferred direction of the asymmetrical cross section of the focal zone formed, which can be optically detected or is detected in particular by means of a detection device.
  • the actuating device is activated by means of the control device with different control signals and in particular control signal values of the control signal.
  • the cross section of the focal zone formed is optically recorded and the preferred direction of the optically recorded cross section is determined.
  • the actual preferred direction is then determined based on the focal zone formed, which is or can be introduced into the material.
  • the actual preferred direction is determined by optical and/or automated evaluation of the recorded cross section, in particular by means of image recognition and/or image data analysis.
  • the actual preferred direction is then determined based on a resulting interaction of the focus zone formed with the material of the workpiece.
  • the actual preferred direction is determined by optical and/or automated evaluation of the detected cross section of the material modification, in particular by means of image recognition and/or image data analysis.
  • the actual preferred direction of the cross section of a specific material modification is determined by optically detecting cracks which are assigned to this material modification.
  • a main extension direction of the cracks is determined to determine the preferred direction.
  • the preferred direction of the cross section of the material modifications actually formed can deviate from the actual preferred direction of the optically recorded cross section of the focal zone formed.
  • the cause can be secondary maxima or optical aberrations around the asymmetrical focal zone. Deviations can also result from preferred directions of the material of the workpiece to be processed, e.g. in the case of a crystalline material.
  • a part of the device referred to as an element in this application can each comprise a plurality of sub-components and/or sub-elements.
  • the terms “at least approximately” or “approximately” generally mean a deviation of at most 10%. Unless otherwise stated, the terms “at least approximately” or “approximately” mean in particular that an actual value and/or distance and/or angle deviates by no more than 10% from an ideal value and/or distance and/or angle , and/or that an actual geometric shape deviates from an ideal geometric shape by no more than 10%.
  • Fig. 1 is a schematic representation of an embodiment of a
  • FIG. 2 shows a schematic representation of a further exemplary embodiment of a device for laser machining a workpiece
  • 3a shows a simulated intensity distribution of an asymmetric
  • 3b shows a schematic representation of the intensity distribution of the asymmetrical cross section of the focal zone
  • FIG. 4 shows a schematic sectional view of material modifications in a material of the workpiece, the material modifications being produced by subjecting the material to the focal zone;
  • FIG. 5a shows a transverse phase distribution associated with the intensity distribution according to FIG. 3a on a beam output side of a beam-shaping element of the device
  • FIG. 5b shows a transverse far-field intensity distribution assigned to the intensity distribution according to FIG. 3a, the focal zone being formed by focusing this transverse far-field intensity distribution
  • Fig. 6 is a schematic cross-sectional view of a
  • Fig. 7 is a schematic cross-sectional view of a
  • Detection device for the optical detection of an actual preferred direction of the asymmetrical cross section of the focal zone formed
  • FIG. 8 shows a schematic representation of a detection device for the optical detection of a cross section of material modifications in the material of the workpiece, which are formed by impinging on the material with the focal zone;
  • 9a shows a micrograph of material modifications arranged in the material of the workpiece, which are produced by subjecting the material to the focal zone;
  • FIG. 9b shows a detailed view of partial area A according to FIG. 9a.
  • FIG. 1 An exemplary embodiment of a device for laser machining a workpiece is shown in FIG. 1 and is denoted by 100 there.
  • the device 100 can be used to produce localized material modifications in a material 102 of the workpiece 104, such as defects in the submicrometer range or at the atomic level, which result in a material weakening to have.
  • the workpiece 104 can be separated at these material modifications. For example, a workpiece segment can be separated from the workpiece 104 by means of the material modifications formed.
  • a focal zone 106 is formed by means of the device 100 and is applied to the material 102 of the workpiece 104 to form material modifications.
  • the focus zone 106 extends along a longitudinal axis 108.
  • the focus zone 106 is elongated and/or elongated parallel to the longitudinal axis 108.
  • the focal zone 106 comprises a plurality of focal points adjacent to one another or is formed from a plurality of focal points adjacent to one another.
  • the workpiece 104 is, for example, plate-shaped and/or panel-shaped.
  • the workpiece 104 has a thickness D which, in particular, is at least approximately constant.
  • the workpiece 104 is made of a transparent material 102, i.e. the material 102 is transparent to a wavelength of a laser beam by means of which the focal zone 106 is formed.
  • the longitudinal axis 108 of the focal zone 106 is oriented parallel or transverse to a thickness direction of the thickness D of the workpiece 104 .
  • the focus zone 106 extends at least over the entire thickness D of the workpiece 104 and/or a workpiece segment to be separated.
  • a total length of the focal zone 106 oriented parallel to the longitudinal axis 108 is, for example, greater than or equal to the total thickness D of the workpiece 104 and/or a workpiece segment to be separated.
  • the device 100 comprises a beam shaping device 110.
  • An input laser beam 112 which is provided by a laser source 114, for example, is coupled into this beam shaping device 110.
  • This input laser beam 112 has a Wavelength for which the material 102 of the workpiece 104 is transparent.
  • This input laser beam 112 is in particular a pulsed laser beam and in particular an ultra-short pulsed laser beam.
  • the input laser beam 112 is a Gaussian beam and/or has a Gaussian beam profile.
  • the input laser beam 112 After being coupled into the beam-shaping device 110 , the input laser beam 112 propagates through the beam-shaping device 110 and is coupled out of the beam-shaping device 110 as a focused output laser beam 113 .
  • the output laser beam 113 forms the focal zone 106 with which the material 102 of the workpiece 104 is impinged.
  • the part of the input laser beam 112 that propagates through the beam shaping device 110 is referred to below as the laser beam 116 .
  • the laser beam 116 has a main propagation direction 118 with which it propagates through the beam shaping device 110 .
  • the main direction of propagation 118 is in particular oriented parallel to a beam axis 120 of the laser beam 116 .
  • This beam axis 120 is to be understood in particular as a longitudinal central axis of the laser beam 116 .
  • the beam-shaping device 110 comprises a beam-shaping element 121, which is embodied, for example, as a diffractive optical element and/or as an axicon element. In principle, it is also possible for the beam-shaping element 121 to be designed as a refractive or reflective element.
  • the beam-shaping element 121 is not necessarily limited to a single element and/or component.
  • the beam-shaping element 121 can comprise a plurality of sub-elements and/or sub-components.
  • Beam-shaping element 121 applies a phase to a transverse beam cross-section 122 of input laser beam 112 and/or laser beam 116, the phase imprint being such that laser beam 116 coupled out of beam-shaping element 121 has a quasi-non-diffracting and/or Bessel-like beam profile.
  • a transverse direction is to be understood as meaning a direction which lies in a plane oriented perpendicularly to the main propagation direction 118 and/or to the beam axis 120 .
  • the beam-shaping device 110 can have adjustment optics 124 for adjusting a diameter do of the beam cross section 122 .
  • the adjustment optics 124 is designed as a telescope or includes a telescope.
  • the adjustment optics 124 are arranged in front of the beam-shaping element 121 with respect to the main propagation direction 118 .
  • the beam shaping device 110 includes focusing optics 126 in order to focus the laser beam 116 coupled out of the beam shaping element 121 in order to form the focal zone 106 .
  • the focusing optics 126 include, for example, one or more lens elements 127.
  • the focusing optics are designed as an objective.
  • the focusing optics 126 are part of a telescope device 128 of the beam shaping device 110 , the laser beam 116 coupled out of the beam shaping element 121 being focused into the focal zone 106 by means of this telescope device 128 .
  • the telescope device 128 comprises lens optics 129 arranged at a distance from the focusing optics 126.
  • This lens optics 129 is or comprises, for example, at least one lens element 130, which is designed, for example, as a converging lens.
  • the lens optics 129 are arranged in front of the focusing optics 126 and/or arranged between the beam-shaping element 121 and the focusing optics 126.
  • the lens optic 129 has a first focal length fi and the focusing optic 126 has a second focal length f2, the first focal length fi being greater than the second focal length f2.
  • a focal plane 132 is assigned to the focusing optics 126 and/or the telescope device 128 . This focal plane is positioned in a far-field region 134 associated with the focusing optics 126 and/or the telescope device 128 .
  • the focal plane 132 and/or the far-field region 134 are positioned between the lens optics 129 and the focusing optics 126 with respect to the main propagation direction 118 .
  • the focal plane 132 is in particular a common focal plane of the lens optic 129 and the focusing optic 126.
  • the focal plane 132 is spaced from the lens optic 129 with the first focal length fi and is spaced from the focusing optic 126 with the second focal length f2.
  • an intermediate image 136 assigned to the focal zone 106 is formed, for example, which is arranged behind the beam-shaping element 121 and/or between the beam-shaping element 121 and the focusing optics 126, in particular with respect to the main propagation direction 118.
  • a further embodiment of a beam-shaping device 110′ shown in FIG. 2 differs from the embodiment of the beam-shaping device 110 described above essentially in that the lens optics
  • the beam-shaping element 121 is integrated into the beam-shaping element 121 and/or forms a unit with the beam-shaping element 121.
  • a functionality of lens optics 129 is integrated into beam-shaping element 121 .
  • the phase distribution impressed on the beam cross-section 122 by means of the beam-shaping element 121 is adapted for the integration of the lens optics 129 in the beam-shaping element 121 .
  • lens optics 129 and/or a lens element can be provided.
  • the lens optics 129 is arranged on a beam exit side 138 of the beam shaping element 121 .
  • the beam-shaping device 110′ basically has the same structure and the same mode of operation as the beam-shaping device 110, so that in this respect reference is made to its description.
  • the beam shaping device 110 ′ has one or more further features and/or advantages of the beam shaping device 110 .
  • the focal zone 106 formed by means of the beam shaping device 110 has an elongated and/or elongate shape with respect to its longitudinal axis 108 . This is realized by the phase imprinting by means of the beam-shaping element 121, with the phase imprinting by means of the beam-shaping element 121 in particular generating a quasi-non-diffracting and/or Bessel-like beam profile.
  • a cross section 140 of the focal zone 106 is asymmetrical, with a cross-sectional plane assigned to the cross section 140 being oriented perpendicularly to the longitudinal axis 108 .
  • a simulated intensity distribution of the asymmetrical cross-section 140 of the focal zone 106 is shown, for example, in FIG. 3a in the form of a gray scale representation.
  • this grayscale representation lighter areas represent areas of higher intensities.
  • a modified intensity distribution is used to determine spatial dimensions of focal zone 106, such as its overall length in the direction of longitudinal axis 108 and/or a diameter dx, d y of cross section 140 in an x-direction or y-direction oriented perpendicularly to longitudinal axis 108 considered, which only has intensity values that are above a certain intensity threshold.
  • this intensity threshold is 50% of a global intensity maximum of the actual intensity distribution. This is illustrated schematically in FIG. 3b for the diameters dx, d y of the cross section 140 of the focal zone 106 .
  • the total length of the focus zone is to be understood, for example, as a maximum extension length and/or a length of maximum extension of the focus zone 106 along the longitudinal axis 108 based on the modified intensity distribution mentioned.
  • the diameter dx or d y is to be understood as meaning a maximum extension length and/or a length of maximum extension of the cross section 140 of the focal zone 106 in the x-direction or y-direction.
  • the focal zone 106 is to be understood in particular as a global maximum intensity distribution 142 which is in particular spatially coherent. In particular, only this global maximum intensity distribution 142 is relevant for an interaction with the material 102 of the workpiece 104 for the formation of material modifications.
  • the maximum intensity distribution 142 is in particular surrounded by secondary intensity distributions 144 .
  • These secondary intensity distributions 144 are in particular arranged around the maximum intensity distribution 142 and/or arranged at a distance from the maximum intensity distribution 142 .
  • the secondary intensity distributions 142 are or include, in particular, secondary maxima.
  • the secondary intensity distributions 144 are insignificant for the laser processing of the workpiece 104, since their lower intensities result in no and/or negligible formation of material modifications in the material 102.
  • the asymmetrical cross section 140 of the focal zone 106 has a preferred direction 146 which lies in a plane oriented perpendicular to the longitudinal axis 108 of the focal zone 106 .
  • the preferred direction 146 is to be understood as meaning a direction in which the asymmetrical cross section 140 has the greatest spatial extent and/or the greatest diameter.
  • the largest spatial extent and/or the largest diameter of the cross section 140 are oriented parallel to the x-direction.
  • the preferred direction 146 is oriented parallel to the x-direction and/or parallel to a direction of the diameter dx.
  • cross section 140 is elliptical and/or at least approximately embodied as an ellipse.
  • the preferred direction 146 then corresponds, for example, to a direction of a major semi-axis of the ellipse.
  • the diameter dx is then oriented parallel to the major semi-axis and the diameter d y is oriented parallel to the minor semi-axis.
  • the focal zone 106 is moved in a feed direction 148 relative to the material 102 (FIG. 4).
  • material modifications 150 are formed in the material 102, which are arranged and/or lined up along the longitudinal axis 108 of the focal zone 106.
  • a distance between mutually adjacent material modifications 150 parallel to the feed direction 148 depends in particular on a feed speed at which the focal zone 106 is moved in the feed direction 148 relative to the material 102 .
  • material modifications 150 are formed along a processing surface along which the material 102 in particular can be separated. Material can be separated along the processing surface, for example, by exerting a mechanical force.
  • the material modifications 150 have a cross section 152 which has a shape corresponding to the cross section 140 of the focal zone 106 .
  • a cross-sectional plane assigned to cross section 152 is oriented perpendicularly to longitudinal axis 108 and/or parallel to feed direction 148 of focal zone 106 with which corresponding material modification 150 was formed.
  • the cross section 152 of a specific material modification 150 has a preferred direction 154 which corresponds to the preferred direction 146 of the cross section 140 of that focal zone 106 with which the material modification 150 was formed.
  • the material modification 150 has the greatest spatial extent and/or the greatest diameter in the direction of the preferred direction 154 .
  • the cross section 152 is designed as an ellipse and the preferred direction 154 corresponds to a direction of a major semi-axis of the ellipse.
  • the laser parameters assigned to the focal zone 106 are selected such that the material modifications 150 formed in the material 102 by means of the focal zone 106 are accompanied by the formation of cracks 156 in the material 102 .
  • Material Mods 150 are Type III Mods.
  • the cracks 156 extend in particular between adjacent material modifications 150 which are spaced apart from one another in the feed direction 148 .
  • cracks 156 extend along a main extension direction 158, which are oriented at least approximately parallel to preferred direction 154 of material modification 150 associated with these cracks 156 and/or are oriented at least approximately parallel to preferred direction 146 of focal zone 106, by means of which these Cracks 156 associated material modification 150 was formed.
  • the main extension direction 158 is to be understood in particular as an average and/or averaged extension direction of the cracks 156 associated with a specific material modification 150 .
  • the beam-shaping device 110 comprises at least one preferred direction beam-shaping element 160 for forming the asymmetrical cross-section 140 of the focal zone 106 with the preferred direction 146.
  • the preferred direction beam-shaping element 160 can be changed, preferably in a plane oriented perpendicularly to the longitudinal axis 108 of the focal zone 106 and/or adjustable.
  • the preferred direction beam-shaping element 160 and/or a functionality of the preferred direction beam-shaping element 160 is integrated into the beam-shaping element 121 .
  • the asymmetrical cross section 140 of the focal zone 106 is realized by the phase imprinting taking place by means of the beam-shaping element 121 .
  • FIG. 5a shows an example of a transverse phase distribution which is impressed on the beam cross section 122 by means of the beam shaping element 121 in order to form the focal zone 106 with an asymmetrical cross section 140 .
  • laser beam 116 is coupled out at beam output side 138 of beam-shaping element 121 with this phase distribution.
  • the phase distribution has a plurality of angle segments 162a, 162b, wherein mutually adjacent angle segments have different azimuthal segment widths Dbi, Db2 and/or have a segment lattice phase difference.
  • FIG. 5b An example of a far-field transverse intensity distribution 164 formed in the focal plane 132 and/or the far-field region 134 of the beam-shaping device 110 is shown in FIG. 5b.
  • This far-field intensity distribution 164 results from the phase imprinting performed by means of the beam-shaping element 121 .
  • the far-field intensity distribution 164 includes a ring structure.
  • the ring structure is designed in particular as a ring segment structure and/or comprises a plurality of ring segments 166 which are arranged in particular concentrically with respect to the beam axis 120 .
  • all ring segments 166 of the ring structure have the same radius.
  • the ring structure of the far-field intensity distribution 164 includes one or more discontinuities 168 located between adjacent ring segments 166 . These interruptions 168 extend in particular in one or more azimuthal angular ranges ring structure. In particular, the intensity at these interruptions 168 is zero or the intensity is at least 90% less than an intensity of the adjacent ring segments 166.
  • the focal zone 106 is formed by focusing the far-field intensity distribution 164 by means of the focusing optics 126 and/or by means of the telescopic device 128 . Due to the ring structure with the interruptions 168, the focal zone 106 is formed with an asymmetrical cross section 140. FIG.
  • the preferred direction 146 of the asymmetrical cross section 140 can be changed and/or set, for example, by rotating the beam-shaping element 121 , with an axis of rotation being oriented in particular parallel to the beam axis 120 or corresponding to the beam axis 120 .
  • the preferred direction beam-shaping element 160 is or includes a beam stop 170 in order to form the focal zone 106 with an asymmetrical cross section 140 .
  • the beam stop 170 is configured to block one or more angular ranges of the ring structure of the far-field intensity distribution 164 , the blocked angular ranges of the ring structure in particular not being focused by means of the focusing optics 126 .
  • the beam diaphragm 170 is arranged in particular in the far-field region 134 and/or in the focal plane 132 .
  • the beam-shaping element 121 is designed to form the far-field intensity distribution 164 with a ring structure, which has a continuous and/or uninterrupted ring. Resulting interruptions 168 are then produced on this ring structure by blocking angular areas of the ring structure using the beam stop 170 .
  • the ring structure focused by means of the focusing optics 126 then has, for example, the structure shown in FIG. 5b.
  • the preferred direction 146 of the asymmetrical cross-section 140 can be in this embodiment, for example, by changing the means of Change beam diaphragm 170 blocked angular areas of the ring structure of the far-field intensity distribution and / or adjust.
  • the blocked angular ranges can be changed by adjusting and/or rotating the beam stop 170, with an axis of rotation preferably being oriented parallel to or coincident with the beam axis 120.
  • the preferred direction beam-shaping element 160 is or comprises at least one polarization beam-splitting element 172, an exemplary embodiment of the polarization beam-splitting element 172 being shown in FIG.
  • the polarization beam splitting element 172 is arranged in particular in the far-field region 132 and/or in the focal plane 132 .
  • the laser beam 116 incident on the polarization beam splitting element 172 is split by means of the polarization beam splitting element 172 into mutually different sub-beams 174a, 174b with different polarization states.
  • the stated polarization states are to be understood as meaning linear polarization states, with two different polarization states being provided, for example, and/or polarization states oriented perpendicularly to one another being provided.
  • beams coupled out of the polarization beam splitting element 172 are polarized in such a way that an electric field is oriented in a plane perpendicular to the main propagation direction 118 (transversally electric).
  • the partial beams 174a, 174b have a spatial offset Dc and an angular offset Da, with one of the partial beams 174a, 174b in particular being oriented parallel to the beam axis 120 of the incident laser beam or coinciding with it.
  • the polarization beam splitting element 172 comprises a birefringent polarizer element 176 and an isotropic element 178, which is arranged in particular behind the polarizer element 176 with respect to the main propagation direction 118.
  • the polarizer element 176 and/or the isotropic element 178 are wedge-shaped, for example.
  • An optical axis 180 of polarizer element 176 is oriented, for example, at an angle of at least approximately 45° to a beam input side 182 of polarizer element 176 and/or to beam axis 120 .
  • the polarized partial beams 174a, 174b After focusing by means of the focusing optics 126, the polarized partial beams 174a, 174b have a spatial offset.
  • the partial beams 174a, 174b are focused in different partial areas of the focal zone 106, which overlap at least in sections.
  • the focal zone 106 can be formed with an asymmetrical cross section 140 .
  • the preferred direction 146 of the asymmetrical cross section 140 can be changed and/or set, for example, by rotating the polarization beam splitting element 172, preferably about the beam axis 120 or about an axis parallel to the beam axis 120.
  • the device 100 includes an adjusting device 184, by means of which the preferred direction 146 of the asymmetrical cross section 140 of the focal zone 106 can be changed during the laser processing of the workpiece 104.
  • a change and/or setting of the preferred direction 146 is to be understood in particular as meaning that an orientation of the preferred direction 146 in a plane oriented perpendicular to the longitudinal axis 108 of the focal zone 106 is changed or set.
  • the adjusting device 184 influences the preferred direction beam-shaping element 160, such as the beam-shaping element 121 and/or the beam stop 170 and/or the Polarization beam splitting element 172.
  • the preferred direction beam shaping element 160 can be moved and/or rotated by means of the adjusting device 184 in order to change the preferred direction 146.
  • the device 100 further includes a control device 186 which is connected to the actuating device 184 in a signal-effective manner.
  • the actuating device 184 is actuated by means of the control device 186 on the basis of an assignment specification.
  • This assignment rule is stored in particular in a database 188 which is included in the control device 186 or to which the control device 186 is connected in a signal-effective manner.
  • the preferred direction 146 is controlled by the control device 186 in particular in such a way that the preferred direction 146 is oriented parallel or approximately parallel to the feed direction 148.
  • the control device 186 controls the setting device 184 on the basis of the assignment rule with a control signal in order to bring about the corresponding orientation of the preferred direction 146 .
  • the assignment rule is or includes an assignment table, for example, which contains an assignment of control signal values of the control signal to orientation values of the preferred direction 146 .
  • the orientation values of the preferred direction 146 can be specified, for example, as angle information of an angle Q to a reference direction 190 , the reference direction 190 lying in a plane oriented perpendicularly to the longitudinal central axis 108 .
  • the device 100 comprises a detection device 192, by means of which an actual preferred direction 194 (indicated in FIG. 7) of the cross section 140 of the focus zone 106 formed can be optically detected.
  • the actual preferred direction 194 is to be understood, in particular, as an actual preferred direction of the cross section 140 as it is present, for example, in the material 102 and/or as determined by the detection device 192 .
  • the focus zone 106 is formed by means of the beam shaping device 110 and the work piece 104 is acted upon by the focus zone 106 .
  • the focal zone 106 formed is optically detected by the detection device 192 .
  • the detection device 192 comprises, in particular, an image recording device 196, which has an image sensor and/or a camera, for example. Furthermore, the detection device 192 comprises, in particular, imaging optics 198 in order to image the focal zone 106 formed by means of the beam shaping device 110 onto the image recording device 196 .
  • the detection device 192 is arranged in particular behind the workpiece 104 and/or the focus zone 106 that has been formed.
  • the actual preferred direction 194 can be determined by evaluating image data recorded by means of the image recording device 196 , it being possible for the evaluation to be carried out by means of the control device 186 , for example.
  • the detection device 192 is then connected to the control device 186 in a signal-effective manner.
  • FIG. 8 A further embodiment of an optical detection device 192' is shown in FIG. 8 and differs from the detection device 192 described above essentially in that, in the case of the detection device 192', a material modification 150 formed in the material 102 of the workpiece 104 by means of the focal zone 106 is optically detected in order to determine their preferred direction 154 (cf. FIG. 4). Otherwise, the detection device 192′ has, in particular, one or more features and/or advantages of the detection device 192, so that reference is made to its above description in this respect.
  • the preferred direction 154 of the cross section 152 of a material modification 150 formed by means of the focal zone 106 by detecting the preferred direction 154 of the cross section 152 of a material modification 150 formed by means of the focal zone 106, the actual preferred direction 194 of the focal zone 106 with which this material modification 150 was formed is inferred.
  • the preferred direction 154 of the assigned material modification 150 corresponds to the actual preferred direction 194 and/or the actual preferred direction of the focal zone 106, by means of which this material modification 150 was formed.
  • the detection device 192 ′ includes, for example, the image recording device 196 and imaging optics 198 ′ in order to image the material modification 150 onto the image recording device 196 .
  • the cross section 152 of the material modification 150 and/or the cracks 156 associated with the material modification 150 are optically recorded by means of the image recording device 196 .
  • the preferred direction 154 and/or the actual preferred direction 194 can be determined by evaluating image data recorded by means of the image recording device 196 . Provision can be made for the main extension direction 158 of cracks 156, which are associated with this material modification 150, to be used to determine the actual preferred direction 194 of a specific material modification 150.
  • the material modifications 150 formed in the material 102 are detected in reflected-light microscopy.
  • the focusing optics 126 of the beam-shaping device 110 serve as the objective of the imaging optics 198'.
  • the rays incident from the workpiece 104 onto the focusing optics 126 are deflected in the direction of the image recording device 196, for example by means of a partially reflecting element 200 of the imaging optics 198'.
  • Exemplary micrographs of the material 102 with material modifications 150 formed therein are shown in FIGS. 9a and 9b, the material modifications 150 being arranged in a circle in the example shown.
  • the main extension direction 158 of the cracks 156 of an associated material modification corresponds at least approximately to the preferred direction 154 of the cross section 152 of this material modification.
  • the device 100 works as follows:
  • the actuating device 184 is actuated by the control device 186 with different control signal values, for example, and the actual preferred direction 194 is determined for each of the different control signal values.
  • the actual preferred direction 194 is determined here by means of the detection device 192, 192'.
  • the assignment rule is determined in the form of a relationship between different control signal values and orientation values of the actual preferred direction 194 .
  • the assignment specification contains the information with which control signal value the actuating device 184 must be controlled in order to realize a specific actual preferred direction 194 .
  • the actual preferred direction 194 is determined, for example, by optically detecting and evaluating the cross section 140 of the focal zone 106 formed by the beam shaping device 110.
  • the optical detection of the cross section 140 of the focal zone 106 can, for example, be inside or outside the material 102 of the workpiece 104 take place.
  • the cross section 140 is recorded in air.
  • the actual preferred direction 194 is determined, for example, by optical detection and evaluation of the cross section 152 of material modifications 150, which are or were formed by means of the focal zone 106 with different control signal values.
  • FIG. 9 b several material modifications 150 are shown in FIG. 9 b , which are arranged at different positions in the material 102 of the workpiece 104 and were formed with different control signal values or preferential directions 146 .
  • the actual preferred direction 194 is determined, for example, by optically detecting and evaluating the material modifications 150 formed in the material 102, whereby to determine the actual preferred direction 194 of a specific material modification, in particular its cross section 152 and/or the main direction of extension 158 of this material modification 150 are associated with cracks 156 is optically recorded and/or evaluated.
  • the assignment rule can be determined before or during the laser processing of the workpiece 104 .
  • the material 102 of the workpiece 104 is acted upon by the focal zone 106 and the focal zone 106 is moved in the feed direction 148 relative to the workpiece 104 through its material 102 .
  • the material 102 is a material that is transparent to a wavelength of the input laser beam 112 and/or the laser beam 116 from which the focal zone 106 is formed by means of the beam shaping device 110 .
  • material 102 is a glass material such as fused silica.
  • material modifications 150 are formed, which are arranged along a processing surface as described above.
  • the distance from material modifications 150 that are adjacent in the feed direction 148 can be defined, for example, by setting a pulse duration of the input laser beam 112 and/or by setting the feed rate.
  • the material modifications 150 formed along the processing surface result in particular in a reduction in the strength of the material 102 .
  • the material 102 can be separated into two different workpiece segments after the material modifications 150 have formed on the processing surface, for example by exerting a mechanical force.
  • the preferred direction 146 of the asymmetrical cross section 140 of the focal zone 106 is aligned parallel or approximately parallel to the feed direction 148 during the laser processing of the workpiece 104 . This results in a smoother separating surface when the workpiece 104 is separated along the processing surface.
  • the feed direction 148 was not oriented approximately parallel to the feed direction 148 when this material modification 150a was formed.
  • the main extension direction 158 of the cracks 156 associated with the material modification 150a is then not oriented approximately parallel to the feed direction 148 either. Unevenness can result when the workpiece is separated.
  • the preferred direction 146 is controlled and/or regulated by the control device 186 in such a way that the preferred direction 146 is oriented parallel or approximately parallel to the feed direction 148 during the laser processing of the workpiece 104 .
  • Cracks 156 in adjacent material modifications 150 then merge into one another at least approximately continuously and/or without interruption, so that in particular the workpiece can be separated with a smooth separating surface (see, for example, partial area 202 identified in FIG. 9a).
  • Preferred direction beam-shaping element a angular segment b angular segment
  • Polarization beam splitting element a sub-beam b sub-beam
  • Detection device ' detection device actual preferred direction Image recording device 'imaging optics partially reflecting element section

Abstract

La présente invention concerne un appareil pour le traitement au laser d'une pièce à travailler (104) au moyen d'une zone focale (106), la pièce à travailler (104) comprenant un matériau transparent (102), l'appareil comprenant un dispositif de modelage de faisceau (110; 110') pour former la zone focale (106) à partir d'un faisceau laser d'entrée (112), la zone focale (106) possédant une forme allongée reliée à un axe longitudinal (108) et la zone focale (106) ayant, perpendiculaire à l'axe longitudinal (108), une section transversale asymétrique (140) présentant une direction préférée (146), un élément de commande final (184) pour modifier la direction préférée (146) durant le traitement au laser de la pièce à travailler (104), et un dispositif de commande (186) pour commander un élément de commande final (184) sur la base d'une loi de correspondance prédéterminée dans une commande en boucle ouverte et/ou fermée de la direction préférée (146) durant le traitement au laser de la pièce à travailler (104).
EP22730767.5A 2021-06-02 2022-05-23 Procédé et appareil pour le traitement au laser d'une pièce à travailler Pending EP4347171A1 (fr)

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DE102021123801.3A DE102021123801A1 (de) 2021-06-02 2021-09-15 Verfahren und Vorrichtung zur Laserbearbeitung eines Werkstücks
PCT/EP2022/063847 WO2022253606A1 (fr) 2021-06-02 2022-05-23 Procédé et appareil pour le traitement au laser d'une pièce à travailler

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DE102014213775B4 (de) * 2014-07-15 2018-02-15 Innolas Solutions Gmbh Verfahren und Vorrichtung zum laserbasierten Bearbeiten von flächigen, kristallinen Substraten, insbesondere von Halbleitersubstraten
DE102014116958B9 (de) * 2014-11-19 2017-10-05 Trumpf Laser- Und Systemtechnik Gmbh Optisches System zur Strahlformung eines Laserstrahls, Laserbearbeitungsanlage, Verfahren zur Materialbearbeitung und Verwenden einer gemeinsamen langgezogenen Fokuszone zur Lasermaterialbearbeitung
EP3221727B1 (fr) * 2014-11-19 2021-03-17 Trumpf Laser- und Systemtechnik GmbH Système de formage par faisceau optique asymétrique
LT3311947T (lt) 2016-09-30 2019-12-27 Corning Incorporated Skaidrių ruošinių lazerinio apdirbimo, naudojant spindulių pluošto dėmes be simetrijos ašių, būdas
DE102019205394A1 (de) 2019-04-15 2020-10-15 Trumpf Laser- Und Systemtechnik Gmbh Bearbeitungsoptik, Laserbearbeitungsvorrichtung und Verfahren zur Laserbearbeitung
DE102020103884A1 (de) 2019-10-11 2021-04-15 Trumpf Laser- Und Systemtechnik Gmbh Justage-vorrichtung für eine bessel-strahl-bearbeitungsoptik und verfahren
DE102019128362B3 (de) 2019-10-21 2021-02-18 Trumpf Laser- Und Systemtechnik Gmbh Segmentiertes Strahlformungselement und Laserbearbeitungsanlage
DE102019217577A1 (de) 2019-11-14 2021-05-20 Trumpf Laser- Und Systemtechnik Gmbh Verfahren zur Laserbearbeitung eines Werkstücks, Bearbeitungsoptik und Laserbearbeitungsvorrichtung

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