Actively controlled laser processing of transparent workpieces

A method for processing a transparent workpiece, the method comprising:

• forming a contour along a contour line in the transparent workpiece, the contour comprising a plurality of defects in the transparent workpiece and a curved contour portion;
• and
• separating the transparent workpiece along the contour, wherein separating the transparent workpiece comprises:
• directing an infrared laser beam output by an infrared laser beam source along an infrared beam pathway onto the transparent workpiece on or near the contour line to induce formation of a crack in the transparent workpiece;
• translating the transparent workpiece and the infrared laser beam relative to each other along or near the contour line to induce propagation of the crack along the contour, wherein during propagation of the crack, the crack comprises a crack tip;
• detecting a position of the crack tip and a position of an infrared beam spot of the infrared laser beam via an imaging system, wherein the imaging system and the infrared beam source are coaxially positioned, forming an in-line system;
• terminating crack-inducing irradiation from the infrared laser beam when the infrared beam spot reaches a first reference point located along the contour line;
• translating the transparent workpiece and the infrared beam pathway relative to each other from the first reference point to a second reference point located along the contour line, wherein the first reference point is located behind the second reference point and at least some of the curved contour portion is disposed between the first reference point and the second reference point;
• and
• resuming crack-inducing irradiation from the infrared laser beam and translation of the transparent workpiece and the infrared laser beam relative to each other along or near the contour line when the crack tip reaches a third reference point located along the contour line, wherein the first reference point is located behind the third reference point and at least some of the curved contour portion is disposed between the first reference point and the third reference point.

A method for processing a transparent workpiece, the method comprising:

• forming a contour along a contour line in the transparent workpiece, the contour comprising a plurality of defects in the transparent workpiece;
• separating the transparent workpiece along the contour, wherein separating the transparent workpiece comprises:
• directing an infrared laser beam output by an infrared laser beam source onto the transparent workpiece on or near the contour line to induce formation of a crack in the transparent workpiece, wherein the infrared laser beam projects an infrared beam spot on a surface of the transparent workpiece, wherein the portion of the laser beam directed into the transparent workpiece comprises:
• a wavelength λ;
• an effective spot size wo,eff;
• and
• a non-axisymmetric beam cross section that comprises a minimum Rayleigh range ZRx,min in a cross-sectional x-direction and a minimum Rayleigh range ZRy,min in a cross-sectional y-direction, wherein the smaller of and ZRx,min and ZRy,min is greater than
• F
• D
• ⁢
• π
• ⁢
• w
• o
• ,
• eff
• 2
• λ
• ,
• where FD, is a dimensionless divergence factor comprising a value of 10 or greater;
• translating the transparent workpiece and the infrared laser beam relative to each other along or near the contour line to induce propagation of the crack along the contour, wherein during propagation of the crack, the crack comprises a crack tip;
• detecting a position and propagation direction of the crack tip relative to a reference location and propagation direction of the infrared beam spot;
• determining a detected distance between the crack tip and the reference location of the infrared beam spot;
• comparing the detected distance to a preset distance;
• and
• modifying at least one of a power of the infrared laser beam or a speed of relative translation between the infrared laser beam and the transparent workpiece in response to a difference between the detected distance and the preset distance.