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
  • B23K26/36—Removing material
  • B23K26/40—Removing material taking account of the properties of the material involved
• • 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
  • 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
  • B23K26/062—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam
  • B23K26/0622—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
  • B23K26/0624—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses using ultrashort pulses, i.e. pulses of 1ns or less
• • 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
  • B23K26/0643—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising mirrors
• • 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
  • B23K26/08—Devices involving relative movement between laser beam and workpiece
  • B23K26/083—Devices involving movement of the workpiece in at least one axial direction
  • B23K26/0853—Devices involving movement of the workpiece in at least in two axial directions, e.g. in a plane
• • 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
  • B23K26/08—Devices involving relative movement between laser beam and workpiece
  • B23K26/0869—Devices involving movement of the laser head in at least one axial direction
  • B23K26/0876—Devices involving movement of the laser head in at least one axial direction in at least two axial directions
• • 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
  • B23K26/36—Removing material
  • B23K26/38—Removing material by boring or cutting
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B33/00—Severing cooled glass
  • C03B33/02—Cutting or splitting sheet glass or ribbons; Apparatus or machines therefor
  • C03B33/0222—Scoring using a focussed radiation beam, e.g. laser
• • 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
  • B23K2101/00—Articles made by soldering, welding or cutting
  • B23K2101/36—Electric or electronic devices
  • B23K2101/40—Semiconductor devices
• • 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
  • B23K2103/52—Ceramics
• • 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
• • 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
  • B23K2103/56—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26 semiconducting

Definitions

• the present invention relates to a device and a method for separating a material using ultra-short laser pulses.
• a particular area of application for such laser radiation is cutting and processing in front of workpieces.
• the laser beam is preferably introduced into the material with vertical incidence, since reflection losses on the surface of the material are then minimized.
• an angle of attack for example for chamfering a material edge, or the creation of chamfer and/or bevel structures with angles of attack of more than 30°, there is still an unsolved problem, especially because the high angle of attack on the Material edge lead to a strong aberration of the laser beam and so no targeted energy deposition can take place in the material.
• a method for separating a workpiece comprising a transparent material
• material modifications are introduced into the transparent material of the workpiece along a separating line by means of ultra-short laser pulses of an ultra-short pulse laser and the workpiece is then separated in a separating step along the resulting material modification surface.
• the laser pulses are introduced into the transparent material of the workpiece at an angle of incidence and the material modifications are Type I and/or Type II modifications which are associated with a change in the refractive index of the transparent material of the workpiece.
• the ultra-short pulse laser provides ultra-short laser pulses.
• ultra-short can mean that the pulse length is between 500 picoseconds and 10 femtoseconds, for example, and in particular between 10 picoseconds and 100 femtoseconds.
• the ultra-short laser pulses move in the beam propagation direction along the laser beam formed by them.
• the intensity in the focus volume can result in non-linear absorption by, for example, multiphoton absorption and/or electron avalanche ionization processes.
• This non-linear absorption leads to the generation of an electron-ion plasma, which can induce permanent structural changes in the material of the workpiece when it cools down. Since energy can be transported into the bulk of the material by nonlinear absorption, these structural changes can be generated inside the sample without affecting the surface of the workpiece.
• a transparent material is understood herein to mean a material that is essentially transparent to the wavelength of the laser beam of the ultrashort pulse laser.
• the terms "material” and “transparent material” are used interchangeably here - the material mentioned here is therefore always to be understood as material that is transparent to the laser beam of the ultrashort pulse laser.
• 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 laser parameters such as the pulse duration, the wavelength, the pulse energy and the repetition frequency of the laser, on the material properties such as, among other things, the electronic structure and the thermal expansion coefficient, as well as the numerical aperture (NA) of the focusing.
• NA numerical aperture
• the type I isotropic refractive index changes are attributed to localized melting caused by the laser pulses and rapid resolidification of the transparent material.
• the density and refractive index of the material is higher when the fused silica is rapidly cooled from a higher temperature. So if the material in the focus volume melts and then cools down quickly, the quartz glass has a higher refractive index in the areas of material modification than in the unmodified areas.
• the type II birefringent refractive index changes can arise, for example, as a result of interference between the ultrashort laser pulse and the electric field of the plasma generated by the laser pulses. This interference leads to periodic modulations in the electron plasma density, which leads to a birefringent property, i.e. direction-dependent refractive indices, of the transparent material when it solidifies.
• a type II modification is also accompanied, for example, by the formation of so-called nanogratings.
• the voids (cavities) of the type III modifications can be produced, for example, with a high laser pulse energy.
• 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 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.
• voids can also be associated with type I and type II modifications.
• Type I and Type II modifications can arise in the less stressed areas around the introduced laser pulses. Therefore, if a type III modification is introduced, then in any case a less dense or hollow core or a defect is present.
• a type III modification of sapphire the microexplosion does not create a cavity, but rather an area of lower density. Due to the material stresses that occur in a type III modification, such a modification is often accompanied by cracking or at least encourages it. the Formation of type I and type II modifications cannot be completely prevented or avoided when introducing type III modifications. Finding "pure" Type III modifications is therefore not likely.
• the material cannot cool completely between pulses, so that cumulative effects of the introduced heat from pulse to pulse can influence the material modification.
• the repetition frequency of the laser can be higher than the reciprocal of the heat diffusion time of the material, so heat accumulation can take place in the focal zone by successive absorption of laser energy until the melting temperature of the material is reached.
• a larger area than the focus zone can be melted due to the thermal transport of the heat energy into the areas surrounding the focus zone.
• the material modifications are introduced into the material along a parting line.
• the parting line describes the line of impact of the laser beam on the surface of the workpiece.
• the laser beam and the workpiece are shifted relative to one another at a feed rate, so that the laser pulses hit the surface of the workpiece at different locations as time progresses.
• the feed rate and/or the repetition rate of the laser is selected in such a way that the material modifications in the material of the workpiece do not overlap, but are separate from one another in the material.
• Displaceable relative to one another means here that both the laser beam can be displaced translationally relative to a stationary workpiece and that the workpiece can be displaced relative to the laser beam. It may also be the case that both the workpiece and the laser beam move. While the workpiece and laser beam are moved relative to each other, the ultra-short pulse laser emits laser pulses into the material of the workpiece at its repetition frequency.
• a characteristic of the material modifications in the beam propagation direction creates an area in the material of the workpiece in which all material modifications lie and which intersects the surface of the workpiece along the parting line.
• the area in which the material modifications lie is called the material modification area.
• the material modification surface can also be curved, so that material modifications that form, for example, the outer surface of a cylinder or a cone are also located in a material modification surface.
• the laser pulses are introduced into the material of the workpiece at a so-called angle of incidence.
• the angle of attack is given here as the angle difference between the laser beam and the surface normal of the workpiece to be cut. When the angle of attack is non-zero, the material modification surface is also inclined with respect to the surface normal of the workpiece.
• the laser beam is refracted according to Snell's law of refraction depending on the refractive index of the surrounding medium, preferably air, and the material of the workpiece.
• the beam propagation direction in the material of the workpiece can deviate from the beam propagation direction before entering the material of the workpiece.
• the material modification surface can also be tilted at an angle other than the angle of impact with respect to the surface normal.
• Type I and II modifications are used here in order to create predetermined breaking points in the material or to weaken the material along the material modification surface.
• the material weakening introduced in Type I and Type II means that the material can be separated along the material modification surface.
• the separation along the material modification surface is carried out by a separation step, so that the workpiece is divided into the bulk part and the so-called section of the workpiece.
• the separation step can comprise a mechanical separation and/or a chemical separation step, preferably an etching process and/or thermal treatment and/or a self-separation step.
• a thermal impact can be, for example, heating of the material or the parting line or the parting surface.
• the parting line or the parting surface can be heated locally by means of a continuous wave CO2 laser, so that the material in the material modification area expands differently compared to the untreated or unmodified material.
• thermal stress is implemented by means of a stream of hot air, or by baking on a hot plate, or by heating the material in an oven.
• temperature gradients can also be applied in the separating step in order to bring about different thermal expansion in the material.
• a mechanical separation can be produced by applying a tensile or bending stress, for example by applying a mechanical load to the parts of the workpiece separated by the separating line or separating surface.
• a tensile stress can be applied when opposing forces act on the parts of the workpiece separated by the separating line or separating surface in the material plane at one force application point each pointing away from the separating line or separating surface. If the forces are not aligned parallel or antiparallel to one another, this can contribute to the development of bending stress.
• the workpiece is separated along the parting surface.
• a mechanical change can also be achieved by a pulsating effect on the part to be separated.
• a lattice vibration can be generated in the material by an impact. Due to the deflection of the lattice atoms, tensile and compressive stresses can also be generated, which can trigger cracking in the material modification surface.
• the material can preferably be separated by etching with a wet-chemical solution, with the etching process preferably starting the material at the material modification, ie at the targeted material weakening. In other words, the selective etchability is increased by introducing the material modifications. Because the parts of the workpiece weakened by the material modification are preferably etched, this leads to the workpiece being separated along the separating surface.
• Heat accumulation can be achieved by successive absorption of the ultra-short laser pulses, provided that the pulse rate of the laser beam is greater than the rate of heat removal through material-specific heat transport mechanisms. Due to the rising temperature in the material of the workpiece, the melting temperature of the material of the joining partner can finally be reached, which leads to local melting of the material. As a result, in particular a type I and/or a type II modification can be produced in the material of the workpiece, as described above.
• a large number of laser pulses can be emitted at one location in the material, with these locations having to overlap sufficiently spatially, see above that heat accumulation can be achieved despite the applied feed.
• the pulse overlap can be greater than 1, so that more than one pulse is emitted per point of impact.
• the spatial overlap must be greater than 1, with the overlap being given by df * R / V, where df is the beam diameter or the diameter of the transverse intensity distribution, see below, R is the repetition frequency of the laser, V is the feed rate.
• the diffusion time in fused silica is 1 ps.
• the material modifications penetrate two sides of the workpiece, which lie in intersecting planes, and a chamfer and/or a shaped edge, preferably a chamfer and/or a bevel, is produced by the separating step.
• Two sides lie in intersecting planes if the face normals of the planes are not parallel to each other.
• a box has two sides that lie in intersecting planes if the sides can be connected by an edge of the box.
• the peripheral surface of the disc is, as it were, in an intersecting plane with the top and bottom of the disc.
• a rectangular cross-section also results in a pane in the plane of incidence of the laser beam.
• the material modifications penetrate both abutting sides. Penetration here means that the material modification begins on one side and ends on the other side in the direction of beam propagation. However, it can also mean that the material modification only runs within the material of the workpiece in order to avoid material breakouts on the surface. In this case, however, much of the path of the laser between the two sides must be modified with material modifications.
• a material modification is continuous over the entire route between the pages.
• this section can be triangular.
• a triangular section of the workpiece has a so-called hypotenuse, which is opposite the edge to be separated.
• the length of the hypotenuse is given by the length of the material modifications in the workpiece.
• the distance from a side adjoining the hypotenuse of the section is given by the distance from the dividing line to the edge of the workpiece.
• the predetermined breaking point is introduced over the entire length of the hypotenuse.
• the workpiece is separated along the material modification surface.
• the material modification surface becomes the so-called shaped edge of the material after cutting.
• a shaped edge of the workpiece is subdivided into so-called chamfers and bevels.
• a chamfering of the workpiece is understood here as a folding in which the original edge of the cuboid is replaced by two edges. This softens the original edge or creates a transition area from a first cuboid side to a second cuboid side.
• a bevel is generated when either the hypotenuse of the section coincides with an edge of the workpiece or generally when one side of the triangular section coincides with at least one side length of the workpiece running parallel thereto.
• hypotenuse of the chamfer and/or the bevel is between 50 pm and 500 pm, preferably between 100 pm and 200 pm.
• the workpiece can be chamfered in a way that is visually particularly appealing and appears to be of high quality.
• thicker workpieces can also be chamfered.
• a more stable edge can also be achieved that does not chip off as easily as an edge with a 90° angle during further processing, installation or use by an end customer.
• the laser beam can be a non-diffractive laser beam.
• Non-diffracting rays and/or Bessel-like rays are to be understood in particular as rays in which a transverse intensity distribution is propagation-invariant.
• a transverse Intensity distribution along a longitudinal direction and / or propagation direction of the beams is substantially constant.
• a transversal intensity distribution is to be understood as meaning an intensity distribution which lies in a plane oriented perpendicularly to the longitudinal direction and/or direction of propagation of the beams.
• the intensity distribution is always understood to be that part of the intensity distribution of the laser beam that is greater than the modification threshold of the material. This can mean, for example, that only a few or just a few intensity maxima of the non-diffracting beam can introduce a material modification into the material of the workpiece.
• the word focal zone can also be used for the intensity distribution in order to make it clear that this part of the intensity distribution is provided in a targeted manner and that an intensity increase in the form of the intensity distribution is achieved by focusing.
• non-diffracting laser beams have the advantage that they can have an intensity distribution that is elongated in the direction of beam propagation and that is significantly larger than the transverse dimensions of the intensity distribution.
• material modifications that are elongated in the beam propagation direction can be produced as a result, so that they can penetrate two sides of the workpiece in a particularly simple manner.
• the laser beam may have a non-radially symmetric transverse intensity distribution, where the transverse intensity distribution appears elongated in a first axis compared to a second axis, the second axis being perpendicular to the first axis.
• non-radially symmetrical means that the transversal intensity distribution depends not only on the distance from the optical axis, but also at least on the polar angle around the direction of beam propagation.
• a non-radially symmetrical transverse intensity distribution can mean, for example, that the transverse intensity distribution is, for example, cross-shaped, or is triangular or N-shaped, for example is pentagonal.
• a non-radially symmetrical transverse intensity distribution can also include further rotationally symmetrical and mirror-symmetrical beam cross sections.
• a non-radially symmetrical transverse intensity distribution can also have an elliptical shape, the ellipse having a long axis A and a short axis B perpendicular thereto.
• the elliptical transverse intensity distribution of the laser beam can correspond to an ideal mathematical ellipse.
• the non-radially symmetrical transverse intensity distribution of the non-diffracting laser beam can also only have the above-mentioned ratios of long main axis and short main axis, but have a different contour - for example an approximated mathematical ellipse, a dumbbell shape or another symmetrical or asymmetrical contour that is enveloped by a mathematically ideal ellipse.
• elliptical non-diffracting beams can be generated via non-diffracting beams.
• Elliptically non-diffracting beams have special properties that result from the analysis of the beam intensity.
• elliptical quasi-non-diffractive beams have a main maximum that coincides with the center of the beam. The center of the beam is given by the place where the main axes intersect.
• elliptical, quasi non-diffracting beams can result from the superimposition of a plurality of intensity maxima, in which case only the envelope of the intensity maxima involved is elliptical.
• the individual intensity maxima do not have to have an elliptical intensity profile.
• the material modification in the cross section perpendicular to the direction of beam propagation in the material also becomes non-radially symmetrical. Rather, the shape of the material modification corresponds to the intensity distribution of the non-diffracting beam in the material of the workpiece.
• non-diffracting rays there are in particular areas of high intensity that interact with the material and introduce material modifications, and areas that lie below the modification threshold.
• the non-radially symmetrical transverse intensity distribution relates to the intensity maxima that are above the modification threshold.
• the feed direction is parallel to the long axis of the transversal intensity distribution, for example, a large pulse overlap can be generated particularly easily, as a result of which the feed rate can be increased. This makes the separation process faster and cheaper.
• the first axis and the second axis can appear to be of equal size due to the angle of incidence.
• the mathematical projection of the non-radially symmetrical transverse intensity distribution under the angle of attack onto the surface of the workpiece can lead to distortions of the intensity distribution.
• an originally elliptical intensity distribution can result in a round intensity distribution on the workpiece.
• material modifications are introduced into the material, which have the intensity distribution that result from the projection at the angle of attack onto the surface of the workpiece.
• the non-radially symmetrical transverse intensity distribution appears round due to the angle of attack.
• a round intensity distribution effectively acts to generate the material modifications.
• the projection of the non-radially symmetrical intensity distribution onto the surface of the workpiece can be elongated in the feed direction.
• the material modification surface can be inclined at an angle of up to 35° relative to the surface of the workpiece.
• the angle of attack can be selected such that the material modification surface is inclined at a maximum of 35° to the surface of the workpiece.
• the pulse energy of the laser pulses can be between 10pJ and 50mJ, and/or the average laser power can be between 1W and 1 kW, and/or the laser pulses can be individual laser pulses or part of a laser burst and/or the wavelength of the laser can be between 300nm and 1500nm in size, in particular 1030nm in size.
• the ultra-short pulse laser can provide single laser pulses with a pulse energy of 100pJ, with the average laser power being 5W and the wavelength of the laser being 1030nm.
• a laser burst can comprise 2 to 20 laser pulses, with the laser pulses of the laser burst having a time interval of 10 ns to 40 ns, preferably 20 ns.
• a laser burst can include 10 laser pulses and the time interval between the laser pulses can be 20 ns.
• the repetition frequency of the laser pulses is 50 MHz.
• the laser bursts can be emitted with the repetition frequency of the individual laser pulses in the order of 100 kHz.
• the material-specific thermal properties can be addressed, so that a shaped edge with a particularly high surface quality can be produced.
• material modifications can be introduced into the material of the workpiece that run parallel to the surface normal of the workpiece; in a second process step, material modifications can be introduced into the material of the workpiece that run at an angle to the surface normal of the workpiece, with the material modification surface of the second method step intersects the material modification surface of the first method step, the separating step being carried out after the second method step.
• material modifications are introduced into the material of the workpiece, which can determine the outer dimensions of the workpiece after the separating step.
• the material modifications are incorporated into the Material of the workpiece introduced, through which the chamfer or bevel is created with the separation step.
• the separation step can be carried out after the first and after the second method step, so that two modification steps and two separation steps are necessary in each case.
• the material modifications for cutting to length and for chamfering can also be introduced into the material of the workpiece in a first step and separated in a common cutting step.
• at least one separation step can be saved, as a result of which the method can be carried out in a particularly time-efficient manner.
• the incident laser beam can be polarized parallel to the plane of incidence.
• the refraction of the laser beam at the transition from the surrounding medium to the material of the workpiece does not only depend on the angle of incidence and the refractive index.
• the polarization of the laser beam also plays a major role here.
• the so-called Fresnel equations can be used to show that the transmission of a laser beam polarized parallel to the plane of incidence through a material for an angle of incidence of more than 10° is always greater than the transmission of a laser beam polarized perpendicular to the plane of incidence.
• reflection losses of the laser beam can be minimized in order to achieve an optimal energy yield for the cutting process in the material.
• a particularly advantageous coupling of energy into the material can be achieved when the laser beam is incident at the Brewster angle.
• a device for separating a workpiece comprising a transparent material comprising an ultra-short pulse laser that is set up to provide ultra-short laser pulses, processing optics that are set up to introduce the laser pulses into the transparent material of the workpiece, and a feed device that is set up to do so is to move the laser beam from laser pulses and the workpiece relative to each other along a dividing line with a feed and to orient the optical axis of the processing optics relative to the surface of the workpiece at an angle of incidence.
• the laser pulses are introduced into the transparent material of the workpiece at an angle of attack, with the material modifications type I and/or type II Modifications are those associated with a change in the index of refraction of the material of the workpiece.
• Processing optics can be an optical imaging system, for example.
• processing optics can consist of one or more components.
• a component can be a lens, for example, or an optically imaging free-form surface or a Fresnel zone plate.
• the depth of insertion of the intensity distribution into the material of the workpiece can be determined by the processing optics.
• the placement of the focal zone in the direction of beam propagation can be adjusted.
• a focus zone can be placed on the surface of the workpiece, or preferably placed in the material of the workpiece.
• the focus zone can be set in such a way that the laser beam penetrates two adjacent sides, thus resulting in a material modification that allows the workpiece to be separated over the entire surface by means of one separating step.
• the feed device can be an XY or an XYZ table, for example, in order to vary the point of impact of the laser pulses on the workpiece.
• the feed device can move the workpiece and/or the laser beam in such a way that the material modifications can be introduced next to one another into the material of the workpiece along the parting line.
• a feed device can also have an angular adjustment, so that the workpiece and the laser beam can be rotated through all Euler angles relative to one another. In this way it can be ensured in particular that the angle of attack can be maintained along the entire dividing line.
• the angle between the optical axis of the processing optics and the surface normal of the material of the workpiece is also understood as the setting angle.
• the setting angle of the optical axis of the processing optics and the surface normal can be between 0 and 60°, for example.
• Beam shaping optics can form a non-diffracting laser beam from the laser beam, where the transverse intensity distribution of the non-diffracting laser beam can be non-radially symmetrical, where the non-radially symmetrical transverse intensity distribution can be elongated in a first axis compared to a second axis, and where the second axis is perpendicular to the first axis.
• the beam shaping optics can, for example, be in the form of a diffractive optical element (DOE), a free-form surface in a reflective or refractive design, or an axicon or a microaxicon be formed, or contain a combination of several of these components or functionalities. If the beam shaping optics forms a non-diffracting laser beam from the laser beam in front of the processing optics, then the depth of penetration intensity distribution into the material can be determined by focusing the processing optics. However, the beam shaping optics can also be designed in such a way that the non-diffracting laser beam is only generated by imaging with the processing optics.
• DOE diffractive optical element
• a diffractive optical element is set up to influence the incident laser beam in one or more properties in two spatial dimensions.
• a diffractive optical element is a fixed component that can be used to produce exactly one intensity distribution of a non-diffracting laser beam from the incident laser beam.
• a diffractive optical element is a specially shaped diffraction grating, whereby the incident laser beam is brought into the desired beam shape by the diffraction.
• An axicon is a conically ground optical element that forms a non-diffracting laser beam from an incident Gaussian laser beam as it passes through.
• the axicon has a cone angle ⁇ , which is calculated from the beam entry surface to the lateral surface of the cone.
• the processing optics can include a telescope system which is set up to introduce the laser beam into the material of the workpiece in a reduced and/or enlarged manner.
• Enlarging and/or reducing the laser beam or its transverse intensity distribution allows the laser beam intensity to be distributed over a large or small focal zone.
• the intensity is adjusted by distributing the laser energy over a large or small area, so that it is possible to choose between modification types I, II, and III, in particular by enlarging and/or reducing the size.
• enlarged or reduced material modifications can also be introduced into the material of the workpiece by enlarging or reducing the non-radially symmetrical transverse intensity distribution. Because the, for example, an elliptical transverse intensity distribution is introduced into the material in reduced form, the radius of curvature of the material modifications introduced thereby is also reduced. In other words, a given curvature becomes more acute as it decreases. This can promote the formation of cracks in the material of the workpiece.
• the optical system can be adapted to the given processing conditions, so that the device can be used more flexibly.
• the feed device can comprise an axis device and a workpiece holder, which are set up to move the processing optics and the workpiece along three spatial axes in a translatory manner and in a rotary manner about at least two spatial axes.
• An axis device can be a 5-axis device, for example.
• the axis device can also be a robotic arm that guides the laser beam over the workpiece or moves the workpiece relative to the laser beam.
• the laser beam and the workpiece are moved relative to each other in order to be able to introduce the material modifications along the dividing line, maintaining the angle of incidence relative to the dividing line requires that the laser beam or the workpiece also be rotated locally.
• the material modification surface it is possible for the material modification surface to always have the same angle to the surface of the workpiece.
• such an axis device also makes it possible at the same time to orient a non-radially symmetrical transverse intensity distribution relative to the dividing line, so that material modifications are produced whose preferred direction runs parallel to the dividing line and promote crack formation along it.
• an axis device can also comprise fewer than 5 movable axes, as long as the workpiece holder can be moved about the corresponding number of axes. If, for example, the axis device can only be displaced in XYZ directions, then the workpiece holder can have two rotary axes, for example, in order to rotate the workpiece relative to the laser beam.
• the beam components of the laser beam can hit the workpiece at a maximum angle of incidence of 80° to the surface normal of the workpiece.
• the laser pulses converge to the optical axis, which is oriented at the angle of incidence to the surface normal of the workpiece.
• the partial laser beams of the beam bundle are at an angle to the optical axis of the processing optics. In particular, these angles can have very large or very small angles due to the numerical aperture.
• the reflection and transmission of the laser beam on the surface of the workpiece depends on the angle of incidence and the refractive index. In the case of a grazing incidence of the laser beam, only a small amount of laser light can couple into the material, so that effective material processing is not possible. In addition, this can adversely affect the shape of the non-diffracting beam.
• Polarization optics preferably comprising a polarizer and a wave plate, can be set up to adjust the polarization of the laser beam relative to the plane of incidence of the laser beam, preferably parallel to the plane of incidence.
• a wave plate in particular a so-called lambda/2 plate, can rotate the direction of polarization of linearly polarized light by a selectable angle. This makes it possible to bring the laser beam into a desired polarization.
• a polarizer can be a thin-film polarizer, for example.
• the thin-film polarizer only transmits laser radiation of a specific polarization.
• the state of polarization of the laser radiation can therefore always be controlled by a combination of wave plate and polarizer.
• polarization of the laser beam parallel to the plane of incidence has the advantage that the transmission for an angle of incidence of more than 10° is always greater than when the laser beam is polarized perpendicularly to the plane of incidence.
• the transmission in the case of a parallel polarized laser beam is more constant and more uniform over a large range of angles of incidence than in the case of perpendicularly polarized light.
• processing optics that have a large numerical aperture can also be used.
• an asymmetrical beam reflection would occur on the surface of the workpiece, so that optical aberrations degrade the quality of the material modifications and thus the quality of the interface.
• a beam guidance device can be set up to guide the laser beam to the workpiece, with the beam being guided via a mirror system and/or an optical fiber, preferably a hollow-core fiber.
• a so-called free beam guidance uses a mirror system to guide the laser beam of a stationary ultrashort pulse laser in different spatial dimensions to the beam shaping optics.
• Free beam guidance has the advantage that the entire optical path is accessible, see above that, for example, other elements such as a polarizer and a wave plate can be installed without any problems.
• a hollow core fiber is a photonic fiber that can flexibly transmit the laser beam of the ultrashort pulse laser to the beam shaping optics.
• the hollow-core fiber eliminates the need to adjust mirror optics.
• Control electronics can be set up to trigger a laser pulse emission of the ultrashort pulse laser based on the relative positions of the laser beam and the workpiece.
• control electronics can regulate the pulse output depending on the relative position of the laser beam and the workpiece.
• the feed device can have a position-resolving encoder that measures the position of the feed device and the laser beam. Based on the location information, the pulse output of a laser pulse can be triggered in the ultra-short pulse laser via a corresponding triggering system of the control electronics.
• computer systems can also be used to implement the triggering of the pulse.
• the locations of the laser pulse emission can be specified for the respective dividing line before the material is processed, so that an optimal distribution of the material modifications along the dividing line is ensured.
• the workpiece holder can have a surface that does not reflect and/or scatter the laser beam.
• this can prevent the laser beam from being guided into the material again after it has penetrated the material and again causing a material modification there.
• a non-reflecting and/or non-scattering surface can also increase occupational safety.
• Figure 1 A, B, C, D is a schematic representation of the method
• FIG. 2A, B, C shows a schematic representation of chamfer and bevel structures
• FIG. 3A, B, C, D, E, F another schematic representation of chamfer and bevel structures
• Figure 4A, B is a schematic representation of a non-diffracting laser beam
• Figure 5A, B, C, D, E is another schematic representation of non-diffracting laser beams
• FIG. 6 shows a schematic representation of the material modifications
• Figure 7A, B is a schematic representation of the beam projection on the
• FIG. 8A, B, C, D another schematic representation of the beam projection on the
• FIG. 9 is a graph showing the transmission as a function of
• Figure 10 is a schematic representation of the device for carrying out the
• FIG. 11 A, B, C further schematic representations of the device for carrying out the
• FIG. 1 schematically shows the method for separating a workpiece 1 comprising a transparent material.
• Figure 1A a cross section of a workpiece 1 is shown which the laser beam 20 of an ultrashort pulse laser 2 is incident.
• the laser beam 20 is introduced onto the workpiece 1 at an angle of attack a, which corresponds to the optical axis of the processing optics 3 shown later.
• the laser beam 20 is refracted at the surface 10 of the workpiece 1 according to Snell's law of refraction during the transition into the workpiece 1, so that the laser beam 20 continues in the material of the workpiece 1 at the angle ⁇ to the surface normal N.
• the material of the workpiece 1 is heated in the focal zone 220 of the laser beam 20, preferably heated by heat accumulation.
• the material of the workpiece 1 is melted in the focus zone of the laser beam, the material of the workpiece 1 having a different refractive index compared to the original state when it cools down again.
• the modification of the material of the workpiece 1 in the focal zone 220 is called material modification 5, the material modifications 5 being, in particular, material modifications of type I or II.
• the material of the workpiece 1 is weakened in a targeted manner, so that a targeted separation of the material 1 is made possible with a separating step.
• the pulse energy of the laser pulses can be between 10pJ and 50mJ, and/or the average laser power can be between 1W and 1 kW, and/or the laser pulses can be individual laser pulses or part of a laser burst and/or the wavelength of the laser can be between be 300nm and 1500nm in size. It can also be the case that a laser burst comprises 2 to 20 laser pulses, with the laser pulses of the laser burst having a time interval of 10 ns to 40 ns, preferably 20 ns.
• the ultrashort pulse laser 2 emits laser pulses
• the laser beam 20 and the workpiece 1 are moved relative to one another with a feed rate V, as shown in FIG. 1B.
• This feed V is guided along a parting line 4 which determines where the workpiece 1 is to be parted on the upper side 10 .
• the material modification 5 is also introduced into the material of the workpiece 1 at the angle ⁇ .
• the material modifications 5 can be shaped differently depending on the extent and shape of the focal zone 220 or the intensity distribution, in particular they can be elongated in the beam propagation direction.
• a so-called material modification surface 50 is produced in the material of the workpiece 1 by the simultaneous feed V of the laser beam 20, in which the material modification 5 lies.
• the material modification surface 50 is preferably homogeneous in the material of the workpiece 1 introduced, which can be achieved by a sufficient pulse overlap of the laser pulses in the material 1.
• the workpiece 1 is separated into the so-called bulk workpiece 1 ′ and the so-called section 12 by the material modification surface 50 .
• the material modification surface 50 can be inclined at an angle ⁇ of up to 35° relative to the surface 10 of the workpiece 1 .
• the material modifications 5 in the material modification area 50 weaken the material of the workpiece 1 in a targeted manner, so that the workpiece 1 and the section 12 can be separated particularly easily along this material modification area 50 .
• the section 12 can be separated from the bulk workpiece T over a large area by a chemical action on the section 12 .
• section 12 may be separated from bulk workpiece T in a chemical bath as shown in Figure 1C.
• the material modifications 5 introduced are particularly susceptible to an etching solution, so that the etching process in the material modification area 50 separates the section 12 from the bulk workpiece T.
• FIG. Accordingly, one can also say that the material modification 5 is etched selectively.
• a so-called chamfer and/or a bevel is formed on the bulk workpiece T, as shown in FIG. 1D.
• the edging of the workpiece 1 is also known as a shaped edge of the workpiece 1 .
• the chamfer or bevel are formed by the material modification surface 50, so that the angle of incidence ⁇ of the laser beam 20, the refractive indices of the surrounding medium and the workpiece 1 result in the angle of refraction ß and thus also the alignment of the material modifications 5 and finally the chamfer or bevel.
• the material modification 5 penetrates those sides of the workpiece 1 which form the edge to be chamfered.
• sides 10 and 11 form edge 110 to be chamfered.
• the sides 10 and 11 of the workpiece 1 lie in particular in spatial planes which intersect, the line of intersection of the planes being the edge 110 of the workpiece 1 .
• FIGS 2A to 2C Various possible shaped edges of the material are shown in Figures 2A to 2C.
• the material modification surface 50 intersects the workpiece 1 with the height of the chamfer being less than the height of side 11 and the width of the chamfer being less than side 10. Accordingly, the chamfering replaces the edge 110 with two edges 110' and 110''. As a result, the original edge 110 in particular is blunted or flattened.
• FIG 2B the material modification surface 50 intersects the workpiece 1, with the height of section 12 corresponding to the height of side 11, and the material modification surface 50 and the edge 130 formed by the underside 13 of workpiece 1 and side 11 coincide.
• the number of edges remains constant, but the angle at which sides 13 and 11 meet becomes more acute. Accordingly, the workpiece 1 can be sharpened and/or pointed by forming a bevel 12 .
• the material modification surface 50 intersects the workpiece 1 , the material modification surface intersecting both the top 10 and the bottom 13 of the workpiece 1 .
• the length of the workpiece 1 is reduced overall and the workpiece 1 is also sharpened, as in FIG. 2B.
• hypotenuse H of section 12 is given by the length of the material modifications in the material.
• FIG. 3A B a workpiece 1 is shown in the form of a disc.
• the so-called plane of incidence is defined by the laser beam 20 incident at the angle of incidence ⁇ and the laser beam 20 refracted at the angle ⁇ .
• the previous description can be taken over verbatim.
• FIG. 3C also shows that the chamfering of the disk from FIGS. 3A, B leads to a conically tapering element, so that it is possible to produce a wide variety of shapes on shaped edges through the material modifications 5 introduced.
• FIG. 3D Another example is shown in Figure 3D.
• Material modifications 5 were introduced circumferentially into the workpiece 1, with the parting line 4 being curved and the angle of attack a in the plane of incidence always being kept constant. This results in a rounded chamfer or bevel after the separation step, which has a high optical quality.
• FIG. 3E shows another example in Figure 3E.
• no rounded dividing line 4 was used here.
• the workpiece 1 was successively chamfered on all four sides, so that a crystal-shaped chamfer results at the corners of the workpiece 1 after the cutting step.
• the method is therefore also suitable for giving the workpiece 1 a qualitatively particularly high-quality impression.
• FIG. 3F shows the cross section of the materials 1 from FIGS. 3D and 3F. The cross section clearly shows the formation of a chamfer 14.
• So-called non-diffracting laser beams 20 are suitable for producing material modifications 5 in a particularly simple manner, which penetrate the workpiece 1 at least in sections. Since the length L of the focal zone 220 is greater than the length of the desired hypotenuse H of the section 12, the workpiece 1 can be chamfered in a particularly simple and effective manner.
• a laser beam 20 processed by beam-shaping optics is shown schematically.
• the partial laser beams 200 of the laser beam 20 fall on the workpiece 1 at an angle a' to the optical axis 30, with each partial laser beam 200 being refracted according to its angle a' to the optical axis 30.
• the optical axis 30 in this example of the laser beam 20 is perpendicular to the surface 10 of the workpiece 1, so that the angle of incidence is 0°.
• the partial laser beams 200 are superimposed in the workpiece 1 to form a non-diffracting beam which has an elongated focal zone 220 with the length L.
• the laser beam 20 strikes at an angle, i.e. at a non-vanishing angle of incidence a, aberrations occur in the material, since the upper half of the beam falls on the workpiece 1 at an angle a+a' and the lower half of the beam at an angle a-a'.
• the hypotenuse H of the chamfer and/or the bevel being between 50 pm and 500 pm, preferably between 10 pm and 200 pm.
• FIG. 5A shows the transverse intensity distribution or the focal zone 220 of a non-diffracting laser beam 20.
• the non-diffracting laser beam 20 is a so-called Bessel-Gaussian beam, with the transverse intensity distribution being radially symmetrical in the xy plane, so that the intensity of the non-diffracting laser beam 20 depends only on the radial distance from the optical axis 30 .
• the diameter of the transverse intensity distribution is between 0.25 pm and 10 pm.
• FIG. 5B shows the longitudinal beam cross section, ie the longitudinal intensity distribution.
• the longitudinal intensity distribution shows an elongated region of high intensity, about 3mm in size.
• the longitudinal extent of the focal zone 220 is thus significantly larger than the transverse extent. Analogously to FIG.
• FIG. 5C shows a non-diffracting laser beam which has a non-radially symmetrical transverse intensity distribution.
• the transverse intensity distribution in the y-direction appears stretched and almost elliptical.
• FIG. 5E shows an enlarged section of the transversal intensity distribution from FIG. 5C, the different intensity maxima resulting from the superimposition of the different partial laser beams 200.
• the focal zone 220 is significantly elongated in the horizontal direction A compared to the vertical direction B, with both directions being perpendicular to one another.
• the resulting material modification 5 has the same shape as shown in FIG. In particular, however, the material modifications are introduced into the material 1 in an overlapping manner, so that a homogeneous material modification surface 50 is produced.
• a laser beam 20 with a round or a non-radially symmetrical transverse intensity distribution is projected onto a surface 10 of the workpiece 1 at an angle of incidence ⁇ , then the intensity distribution is distorted in the plane of incidence.
• FIG. 7A, B the laser beam 20 impinges on the surface 10 of the workpiece 1 with a non-radially symmetrical transverse intensity distribution.
• the intensity of the short axis B is distributed over the length B/cos a, so that the short axis B becomes longer as a result of the projection as the angle of attack increases.
• FIG. 8A shows a Bessel-Gauss beam from FIG. 5A perpendicularly incident on the surface 10 of the workpiece 1.
• FIG. 8B With a non-vanishing angle of incidence a, shown in FIG. 8B, the radially symmetrical intensity distribution on the surface 10 of the workpiece 1 becomes an intensity distribution that is elongated in one direction, so that the resulting material modifications 5 have a preferred direction.
• FIG. 8C shows the Bessel beam from FIG. 5C.
• the alignment of the long axis A is retained by the projection onto the surface 10 of the workpiece 1, so that the orientation of the preferred direction of crack propagation of the material modification 5 resulting therefrom does not change.
• the A/B is smaller than the reciprocal of the cosine of the angle of attack a.
• the laser beam 20 can in particular be polarized, preferably polarized parallel to the plane of incidence, in order to minimize reflection losses.
• FIG. 9 shows the transmission of laser radiation through a workpiece 1 with parallel and perpendicular polarization to the plane of incidence according to Fresnel's formulas. In this case, the angle of attack a is shown in particular on the X-axis, but the partial laser beams 20 according to FIG. 4A have a convergence angle a' relative to the optical axis 30.
• the variation for laser beams 20 polarized perpendicularly to the plane of incidence is therefore significantly greater than for light polarized parallel to the plane of incidence.
• FIG. 10 shows an embodiment of the device for carrying out the method.
• the laser pulses are provided by the ultra-short pulse laser 2 and are directed through polarization optics 32 through beam-shaping optics 34 .
• the laser beam 20 is directed onto the workpiece 1 by the beam-shaping optics 34 through a telescope system 36 , the optical axis 30 of the processing optics 3 being oriented at the setting angle a to the surface normal N of the workpiece 1 .
• the polarization optics 32 can comprise a polarizer, which polarizes the laser beam 20 emitted by the ultrashort pulse laser 2, so that it only has a well-defined polarization.
• a subsequent lambda/2 plate can then finally rotate the polarization of the laser beam 20 in such a way that the laser beam 20 can be introduced into the workpiece 1 preferably polarized parallel to the plane of incidence.
• the beam-shaping optics 34 are an axicon in order to shape the incident laser beam 20 into a non-diffracting laser beam.
• the axicon generates from the preferably collimated input beam, a conically tapering laser beam 20.
• the beam-shaping optics 34 can also impress the incident laser beam 20 with a non-radially symmetrical intensity distribution.
• the laser beam 20 can finally be imaged in the workpiece 1 via a telescopic optics 36, which here consists of two lenses 360, 362, with the image being able to be an enlarging or a reducing image.
• a part of the telescope optics 36, in particular the lens 360, can also be integrated into the beam-shaping optics 34.
• a refractive free-form surface or an axicon with a spherically ground rear side can have both the lens function of the lens 360 and the beam-shaping function of the beam-shaping optics 34 .
• FIG. 11A shows a feed device 6 which is set up to move the processing optics 3 and the workpiece 1 in a translatory manner along three spatial axes and to move them in a rotary manner about two spatial axes.
• the laser beam 20 of the ultra-short pulse laser 2 is directed onto the workpiece 1 by processing optics 3 .
• the workpiece 1 is arranged on a support surface of the feed device 6 , with the support surface preferably neither reflecting nor absorbing the laser energy, which the material does not absorb, nor strongly scattering it back into the workpiece 1 .
• the laser beam 20 can be coupled into the processing optics 3 by a beam guidance device 38 .
• the beam guiding device can be a free-space path with a lens and mirror system, as shown in FIG. 11A.
• the beam guidance device 38 can also be a hollow-core fiber with coupling-in and coupling-out optics, as shown in FIG. 11B.
• the laser beam 20 is guided in the direction of the workpiece 1 by a mirror construction and introduced into the workpiece 1 by the processing optics 3 .
• the laser beam 20 causes material modifications 5 in the workpiece 1.
• the processing optics 3 can be moved and adjusted relative to the material with the feed device 6, so that, for example, a preferred direction or an axis of symmetry of the transverse intensity distribution of the laser beam 20 can be adapted to the feed trajectory and thus the dividing line 4 .
• the feed device 6 can move the workpiece 1 under the laser beam 20 with a feed rate V, so that the laser beam 20 introduces material modifications 5 along the desired parting line 4 .
• the feed device 6 has a first axis system 60, with which the workpiece 1 can be moved along the XYZ axes and, if necessary, rotated.
• the Feed device 6 also have a workpiece holder 62, which is designed to hold the workpiece 1.
• the workpiece holder can also have degrees of freedom of movement, so that the long axis of a non-radially symmetrical transverse intensity distribution can always be oriented perpendicularly to the beam propagation direction tangentially to the desired dividing line 4 .
• the feed device 6 can also be connected to control electronics 64 , the control electronics 64 converting the user commands of a user of the device into control commands for the feed device 6 .
• control electronics 64 converting the user commands of a user of the device into control commands for the feed device 6 .
• predefined cutting patterns can be stored in a memory of the control electronics 64 and the processes can be automatically controlled by the control electronics 64 .
• the control electronics 64 can in particular also be connected to the ultrashort pulse laser 2 .
• the control electronics 64 can request or trigger the output of a laser pulse or laser pulse train.
• the control electronics 64 can also be connected to other components mentioned and thus coordinate the material processing.
• a position-controlled pulse triggering can be implemented in this way, with an axis encoder 600 of the feed device 6 being read out, for example, and the axis encoder signal being able to be interpreted by the control electronics 64 as location information. It is thus possible for the control electronics 64 to automatically trigger the delivery of a laser pulse or laser pulse train if, for example, an internal adder unit that adds the distance covered reaches a value and resets itself to 0 after reaching it. For example, a laser pulse or laser pulse train can be emitted automatically into the workpiece 1 at regular intervals.
• the laser pulses or laser pulse trains can be emitted automatically.
• the control electronics 64 can also use the measured speed and the basic frequency made available by the laser 2 to calculate a distance or location at which a laser pulse train or laser pulse should be emitted. In this way it can be achieved in particular that the material modifications 5 form a material modification surface 50 which is as homogeneous as possible.
• FIG. 11C also shows a feed device 6, in which the processing optics are guided over the workpiece 1 via a 5-axis arm in order to introduce material modifications 5 into the workpiece 1.
• the combination of rotation arms makes it possible to move the processing optics along three spatial axes and to rotate them around two spatial axes.

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• 2020
  • 2020-12-18 DE DE102020134197.0A patent/DE102020134197A1/de active Pending
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