Patent ID: 8059268

Claim:
An optical collection and detection system for use in a surface inspection system for inspecting a surface of a workpiece, the surface inspection system having an incident beam projected through a back quartersphere and toward a desired location on the surface to impinge thereon to create reflected light and scattered light, the optical collection and detections system comprising: a detection subsystem operatively coupled to a collector module, the detection subsystem having a light detection unit arranged to detect the scattered light and generate signals in response; a variable polarizing relay assembly positioned between the workpiece surface and the detection subsystem along a detector optical axis and arranged to selectively permit the scattered light having a given polarization orientation to pass therethrough to the detection subsystem, the variable polarizing relay assembly further comprising a polarization selection subsystem for selecting the polarization orientation of the scattered light to be passed therethrough, wherein the detection subsystem has a first light detection unit and a second light detection unit that are fixed relative to each other; and wherein the variable polarizing assembly comprises a dual channel variable rotational assembly that is arranged to simultaneously permit the passage of scattered light of differing polarization orientation to the first light detection unit and the second light detection unit; and wherein the polarization selection subsystem comprises: a beamsplitter cube housed in a rotatable chamber, with the beam splitter having a polarization orientation; a rotational mechanism for rotating the chamber and thus the beamsplitter cube to alter the polarization of the scattered light impinging on the first light detection unit and the polarization of the scattered light impinging on the second light detection unit.