Patent ID: 7477372
Filing Date: 2009-01-13
Classification: G01N

Abstract:
1. An optical scanning system for detection of anomalies on a surface comprising: optics directing a focused beam of radiation onto a sample surface to produce an illuminated spot thereon; one or more sensor(s); one or more optical element(s), each element collecting radiation scattered from the illuminated spot on the surface along a channel and directing the collected and scattered radiation to one of the sensor(s), causing each of the sensor(s) to provide output signals in response thereto, each of the sensor(s) sensing radiation scattered from the surface in directions away from a specular reflection direction of the focused beam and different from those of radiation sensed by the other sensor(s); a bright field detector detecting a specular reflection of the radiation in the beam from the illuminated spot on the surface to provide an output signal; a device causing relative motion between the beam and the surface so that the beam is caused to illuminate different parts of the surface and so that the sensor(s) and the detector provide output signals in response to radiation from different parts of the surface illuminated by the beam; and a processor processing output signals provided by said one or more sensor(s) using one or more threshold level values.