Patent ID: 9062859
Filing Date: 2015-06-23
Classification: F21V,G01N

Abstract:
1. A wafer edge illumination system comprising: a diffuser having a slot formed therein for accepting a wafer edge, the diffuser being adapted to radiate lambertian light onto the wafer edge; at least one light source directed directly into the diffuser with substantially no stray light being emitted and such that light emitted by the diffuser is incident upon the wafer edge in a diffuse, lambertian fashion; a pair of parallel light baffles, each of the pair having a slot formed therein for accepting the wafer edge and each positioned to either side of the diffuser to prevent stray light from contacting the diffuser and to prevent stray light from escaping the diffuser such that the diffuser is a high efficiency light source for illuminating the edge of the wafer.