Apparatuses and methods for synchronous multi-laser processing of transparent workpieces

Abstract

A method for laser processing a transparent workpiece includes focusing a pulsed laser beam output by a pulsed laser beam source into a pulsed laser beam focal line directed into the transparent workpiece, thereby forming a pulsed laser beam spot on the transparent workpiece and producing a defect within the transparent workpiece, directing an infrared laser beam output onto the transparent workpiece to form an annular infrared beam spot that circumscribes the pulsed laser beam spot at the imaging surface and heats the transparent workpiece. Further, the method includes translating the transparent workpiece and the pulsed laser beam focal line relative to each other along a separation path and translating the transparent workpiece and the annular infrared beam spot relative to each other along the separation path synchronous with the translation of the transparent workpiece and the pulsed laser beam focal line relative to each other.

What is claimed is: 
     
         1 . A method for laser processing a transparent workpiece, the method comprising:
 focusing a pulsed laser beam output by a pulsed laser beam source into a pulsed laser beam focal line oriented along a beam propagation direction and directed into the transparent workpiece, thereby forming a pulsed laser beam spot on an imaging surface of the transparent workpiece, wherein:
 the pulsed laser beam focal line generates an induced absorption within the transparent workpiece; and 
 the induced absorption produces a defect along the pulsed laser beam focal line within the transparent workpiece; 
   directing an infrared laser beam output by an infrared beam source onto the transparent workpiece such that the infrared laser beam forms an infrared beam spot on the imaging surface, wherein:
 the infrared beam spot is spaced a spacing distance from the pulsed laser beam spot at the imaging surface; and 
 the infrared laser beam heats the transparent workpiece; 
   translating the transparent workpiece and the pulsed laser beam focal line relative to each other along a separation path, thereby laser forming a plurality of defects that define a contour line within the transparent workpiece along the separation path; and   translating the transparent workpiece and the infrared beam spot relative to each other along the separation path synchronous with the translation of the transparent workpiece relative to the pulsed laser beam focal line such that the pulsed laser beam spot remains spaced the spacing distance from the infrared beam spot during relative motion of the transparent workpiece and the pulsed laser beam focal line and irradiates the transparent workpiece along or near the contour line to separate the transparent workpiece along the contour line.   
     
     
         2 . The method of  claim 1 , wherein the spacing distance comprises from about 1 μm to about 100 mm. 
     
     
         3 . The method of  claim 1 , wherein the infrared laser beam is redirected by a beam directing element onto the transparent workpiece at an approach angle that is non-parallel to the beam propagation direction of the pulsed laser beam. 
     
     
         4 . The method of  claim 3 , wherein the infrared laser beam is directed through a beam conditioning element thereby altering a cross-sectional beam profile of the infrared laser beam. 
     
     
         5 . The method of  claim 1 , wherein:
 the infrared beam spot and the transparent workpiece are translated relative to one another at a speed from about 1 mm/s to about 10 m/s;   the pulsed laser beam focal line and the transparent workpiece are translated relative to each other at a speed that is equal to the speed of relative motion between the infrared beam spot and the transparent workpiece.