Laser Machining Systems and Methods with Vision Correction and/or Tracking

Abstract

Vision correction and tracking systems may be used in laser machining systems and methods to improve the accuracy of the machining. The laser machining systems and methods may be used to scribe one or more lines in large flat workpieces such as solar panels. In particular, laser machining systems and methods may be used to scribe lines in thin film photovoltaic (PV) solar panels with accuracy, high speed and reduced cost. The vision correction and/or tracking systems may be used to provide scribe line alignment and uniformity based on detected parameters of the scribe lines and/or changes in the workpiece.

What is claimed is: 
     
         1 . A laser machining system comprising:
 a part handling system including a workpiece support surface for supporting a workpiece to be machined;   at least one laser source for generating at least one processing laser beam;   an optical head including a beam delivery system for receiving the at least one processing laser beam and for directing the processing laser beam at the workpiece; and   a workpiece tracking system for tracking changes in the workpiece as the processing laser beam moves relative to the workpiece and for adjusting at least one parameter of the processing laser beam in response to the changes in the workpiece, wherein the workpiece tracking system includes at least a laser interferometer sensor for measuring a processing distance to the workpiece.   
     
     
         2 . The laser machining system of  claim 1  wherein the at least one laser interferometer sensor measures a processing distance to at least one surface of the workpiece, and wherein the workpiece tracking system tracks changes in the processing distance to the surface of the workpiece. 
     
     
         3 . The laser machining system of  claim 1  wherein the at least one laser interferometer sensor measures a processing distance to a process plane of the workpiece and wherein the workpiece tracking system tracks changes in the processing distance to the process plane of the workpiece. 
     
     
         4 . The laser machining system of  claim 3  wherein the process plane of the workpiece is located within the workpiece. 
     
     
         5 . The laser machining system of  claim 1  wherein the workpiece tracking system tracks changes in a height of the workpiece relative to the optical head. 
     
     
         6 . The laser machining system of  claim 1  wherein the workpiece tracking system tracks changes in thickness of the workpiece. 
     
     
         7 . The laser machining system of  claim 1  further comprising at least one laser scanning stage positioned relative to the part handling system for linear movement along a scanning axis, wherein the optical head is located on the laser scanning stage. 
     
     
         8 . The laser machining system of  claim 1  wherein the beam delivery system comprises at least one lens for focusing the processing laser beam and a lens translation stage for moving the lens and adjusting the focus of the processing laser beam, and wherein the workpiece tracking system includes a motion controller configured to move the lens translation stage and the lens to adjust the focus of the processing laser beam in response to the changes in the workpiece. 
     
     
         9 . The laser machining system of  claim 1  further comprising at least one optical component configured to adjust fluence of the processing laser beam in response to changes in the workpiece. 
     
     
         10 . The laser machining system of  claim 9  wherein the optical component includes a programmable attenuator. 
     
     
         11 . The laser machining system of  claim 9  wherein the optical component includes beam shaping optics. 
     
     
         12 . The laser machining system of  claim 1  wherein the workpiece tracking system is configured to adjust a laser energy of the laser source in response to changes in the workpiece. 
     
     
         13 . The laser machining system of  claim 1  wherein the at least one laser interferometer sensor includes at least a first laser interferometer sensor positioned relative to the optical head to track changes in the workpiece ahead of the processing laser beam. 
     
     
         14 . The laser machining system of  claim 13  wherein the at least one laser interferometer sensor includes at least a second laser interferometer sensor positioned relative to the optical head to track changes in the workpiece on the other side of the processing laser beam. 
     
     
         15 . The laser machining system of  claim 1  wherein the workpiece tracking system further comprises a spectroscopic sensor for capturing optical emission spectra from material being processed by the processing laser beam, and wherein the workpiece tracking system is configured to adjust at least one processing parameter based on the optical emission spectra. 
     
     
         16 . A method of tracking changes in a workpiece during laser processing, the method comprising:
 mounting the workpiece on a part handling system;   generating at least one processing laser beam from a laser source;   directing the processing laser beam through a beam delivery system to the workpiece while moving the processing laser beam relative to the workpiece;   measuring a processing distance to the workpiece with a laser sensor directed toward the workpiece; and   adjusting a laser parameter in response to changes in the processing distance measured by the laser sensor.   
     
     
         17 . The method of  claim 16  wherein the laser sensor is a laser interferometer sensor. 
     
     
         18 . The method of  claim 16  wherein directing the laser beam through a beam delivery system to the workpiece while moving the laser beam relative to the workpiece includes scanning the processing laser beam across the workpiece. 
     
     
         19 . The method of  claim 16  wherein adjusting a laser parameter includes adjusting a focus of the processing laser beam at the workpiece. 
     
     
         20 . The method of  claim 16  wherein adjusting a laser parameter includes adjusting a fluence of the processing laser beam at the workpiece.