Patent ID: 8378258

Claim:
A method for machining a curved surface of a workpiece, wherein said workpiece is made of a sensitive material having an optical absorption coefficient at a 248 nm wavelength that is less than about 2×10 3 cm −1 , said method comprising: generating a raw laser beam having a wavelength of 248 nm, a repetition rate of at least about 200 Hz and at an energy density of at least about 2000 mJ/cm 2 ; forming said raw laser beam into a line shaped beam; moving a mask defining a pattern such that said line shaped beam is scanned across said mask to form a patterned beam; rotating said workpiece; projecting said patterned beam onto said curved surface of said workpiece as said workpiece rotates; and coordinating motion of said mask and said workpiece such that said patterned beam machines a pattern corresponding to said pattern in said mask, wherein said patterned beam machines the pattern by ablating the sensitive material of said workpiece.