Back quartersphere scattered light analysis

Abstract

An optical collection system for use in a surface inspection system for inspecting a surface of a workpiece. The surface inspection system has an incident beam projected through a back quartersphere and toward a location on the surface of the workpiece to impinge on the surface. This forms a reflected beam that extends along a light channel axis in a front quartersphere, and forms scattered light having a haze scatter portion. The incident beam and the light channel axis form an incident plane. The optical collection system includes back collectors that are positioned in the back quartersphere for collecting the scattered light, where each of the back collectors is disposed in the back quartersphere outside the incident plane, and at a relative minimum in the Rayleigh scatter.

Dependencies are inferred from the claim text.