Patent ID: 7557910
Filing Date: 2009-07-07
Classification: G01N,G06T,Y10T

Abstract:
1. A surface inspection system for inspecting a surface of a workpiece, the surface inspection system comprising: a beam source for projecting a beam toward the surface of the workpiece, an acousto-optical deflector through which the beam is projected, a scanning speed selection device operatively coupled to the acousto-optical deflector for varying a scan speed at which the acousto-optical deflector scans the beam passing through the acousto-optical deflector, a beam compensator for compensating for astigmatism of the beam associated with the variation of the scan speed, wherein the beam compensator comprises a plurality of lenses and a lens positioning device for positioning only one lens at a time of the plurality of lenses in the beam at an output of the acousto-optical deflector, where each of the plurality of lenses provides a unique amount of astigmatism compensation relative to other of the plurality of lenses, a workpiece movement subsystem that moves the workpiece and the beam relative to one another, an optical collection and detection subsystem that collects portions of the beam that are reflected from the surface of the workpiece and generates signals in response, and a processing subsystem for receiving and processing the signals.