Patent ID: 8847113

Claim:
A method for dithering a laser beam to form and widen a trench in a workpiece based on a varying processing velocity along a beam trajectory, the method comprising: imparting, using a first positioning system, a first relative movement of a laser beam path along the beam trajectory with respect to a surface of the workpiece, the beam trajectory corresponding to the trench to cut into the workpiece; determining, using a processor, a second relative movement of the laser beam path along a plurality of dither rows, the second relative movement superimposed on the first relative movement at a predetermined angle with respect to the beam trajectory to widen the trench; selectively changing the processing velocity along the beam trajectory based at least in part on a geometry of the trench to cut into the workpiece, the determination of the second relative movement including compensation for changes in the processing velocity to maintain the predetermined angle for each of the plurality of dither rows; imparting, using a second positioning system, the second relative movement of the laser beam path; and emitting a plurality of laser beam pulses to the workpiece at a plurality of spot locations along the plurality of dither rows to both form the trench in the workpiece running in a direction of the beam trajectory and to widen the trench in a direction defined by the predetermined angle; wherein determining the second relative movement of the laser beam path along the plurality of dither rows comprises: determining a vector defining a dithered spot location along an axis of the first positioning system; rotating the vector into an orientation to position the dithered spot location along a dither row that is substantially perpendicular to the beam trajectory; and further rotating the rotated vector to correct scan field distortion.