Patent ID: 6657715
Filing Date: 2003-12-02
Classification: G01J,G01N

Abstract:
An optical system for detecting anomalies of a sample, comprising:optics directing at least one beam of radiation along a path onto a spot on a surface of the sample at an oblique angle to the surface; a detector; an optical device collecting scattered radiation from the sample surface and originating from the at least one beam and conveying the scattered radiation to said detector for sensing anomalies, said device comprising a radiation collector collecting the radiation from the sample surface, said collector having an axis of symmetry substantially coaxial with a line normal to the surface so that directional scattering information in the collected radiation relative to the beam is retained; and a spatial filter between the detector and the optical device blocking scattered radiation from the sample surface towards the detector except for at least one area having a wedge shape defining an azimuthal collection angle relative to the beam so that only the collected radiation within the azimuthal collection angle reaches the detector.