Method and device for laser processing a workpiece
A method for laser processing of a workpiece that has a transparent material includes dividing an input laser beam into a plurality of sub-beams by using a beam splitting element, focusing the sub-beams coupled out of the beam splitting element to form multiple focus elements, and applying the focus elements to the material of the workpiece for the laser processing. The focus elements are moved relative to the material in a feed direction. A first sub-quantity of the focus elements is arranged in a first plane. A second sub-quantity of the focus elements is arranged in at least one other plane. The first plane and the at least one other plane are spaced apart in the feed direction. The first plane and the at least one other plane are orientated perpendicular to the feed direction.
1 . A method for laser processing of a workpiece which has a transparent material, the method comprising:
dividing an input laser beam into a plurality of sub-beams by using a beam splitter,
focusing and directing the plurality of sub-beams coupled out of the beam splitter into the workpiece, wherein the plurality of sub-beams are focused to multiple focus spots inside the workpiece for producing modifications in the material of the workpiece, wherein the workpiece has a thickness along z-axis,
moving the workpiece and/or the plurality of sub-beams relative to each other in a feed direction that is parallel to y-axis orthogonal to the z-axis, wherein a first sub-quantity plurality of the focus spots lies in a first plane, and a second plurality of the focus spots lies in a second plane, the first plurality and the second plurality of the focus spots being present simultaneously, the first plane and the second plane being perpendicular to the feed direction and spaced apart from each other in the feed direction, and wherein by moving the workpiece and/or the plurality of sub-beams relative to each other in the feed direction, the modifications are produced in the material along a processing surface.
2 . The method according to claim 1 , wherein the focus spots are positioned such that, when the focus spots are viewed in a projection plane orientated perpendicular to the y-axis, at least a sub-quantity of the focus spots associated with the first plane and the focus spots associated with the second plane is positioned at different spatial positions in the projection plane.
3 . The method according to claim 1 , wherein the focus spots are positioned such that, when the focus spots are viewed in a projection plane orientated perpendicular to the y-axis, at least a sub-quantity of the focus spots associated with the first plane and the focus spots associated with the second plane is positioned in the projection plane along a processing line, wherein, by moving the workpiece and/or the plurality of sub-beams relative to each other, the modifications are produced in the material along the processing line.
4 . The method according to claim 3 , wherein, by moving the workpiece and/or the plurality of sub-beams relative to each other, the modifications are produced in the material of the workpiece along the processing surface corresponding to the processing line, wherein the modifications are arranged in a cross-section orientated perpendicular to the y-axis, through the processing surface along the processing line.
5 . The method according to claim 3 , wherein adjacent focus spots arranged along the processing line have an effective distance of at least 2 μm and/or at most 200 μm in the projection plane.
6 . The method according to claim 3 , wherein an effective distance of adjacent focus spots along the processing line in the projection plane and/or an intensity of the focus spots is selected such that the modifications formed in the material enable a severing of the material.
7 . The method according to claim 3 , wherein at least a sub-quantity of adjacent focus spots along the processing line is spaced apart in the projection plane with approximately a same effective distance from one another.
8 . The method according to claim 3 , wherein at least a sub-quantity of adjacent focus spots along the processing line is spaced apart at an effective distance, wherein the effective distance has a first non-zero effective distance component along the z-axis, and/or has a second non-zero effective distance component along x-axis orthogonal to the z-axis.
9 . The method according to claim 3 , wherein an angle of attack between the processing line and an outer side of the workpiece, through which the plurality of sub-beams are coupled into the material of the workpiece, is at least 1° and/or at most 90°, at least in some portions.
10 . The method according to claim 1 , wherein the focus spots are positioned such that, when the focus spots are viewed in a projection plane orientated perpendicular to the y-axis, gaps are formed between adjacent focus spots associated with the first plane, wherein the second plurality of focus spots associated with the second plane is positioned in the gaps.
11 . The method according to claim 1 , wherein a first distance between adjacent focus spots associated with the first plane is at least 3 μm and/or at most 70 μm, and/or a second distance between adjacent focus spots associated with the second plane is at least 3 μm and/or at most 70 μm.
12 . The method according to claim 1 , wherein the dividing the input laser beam by using the beam splitter comprises phase imprinting on a beam cross-section of the input laser beam.
13 . The method according to claim 1 , wherein the modifications in the material of the workpiece are accompanied by a crack formation of the material, and/or wherein the modifications are type III material modifications.
14 . The method according to claim 1 , wherein the modifications in the material of the workpiece are accompanied by a change in a refractive index of the material, and/or the modifications are type I material modifications and/or type II material modifications.
15 . A device for laser processing of a workpiece having a transparent material, the device comprising:
a beam splitter for dividing an input laser beam into a plurality of sub-beams, a focusing optical unit for focusing and directing the plurality of sub-beams coupled out of the beam splitter into the workpiece, wherein the plurality of sub-beams are focused to multiple focus spots inside the workpiece for producing modifications in the material of the workpiece, wherein the workpiece has a thickness along z-axis, and
a feed apparatus for moving the workpiece and/or the plurality of sub-beams relative to each other in a feed direction that is parallel to y-axis orthogonal to the z-axis, wherein the beam splitter and the focusing optical unit are configured so that the focus spots are formed in the material of the workpiece in such a way that a first plurality of the focus spots is arranged in a first plane, and a second plurality of the focus spots is arranged in a second plane, the first plurality and the second plurality of the focus spots being present simultaneously, the first plane and the second plane being perpendicular to the feed direction and spaced apart from each other in the feed direction, and wherein by moving the workpiece and/or the plurality of sub-beams relative to each other in the feed direction, the modifications are produced in the material along a processing surface.