System for detecting anomalies and/or features of a surface

摘要

A cylindrical mirror or lens is used to focus an input collimated beam of light onto a line on the surface to be inspected, where the line is substantially in the plane of incidence of the focused beam. An image of the beam is projected onto an array of charge-coupled devices parallel to the line for detecting anomalies and/or features of the surface, where the array is outside the plane of incidence of the focused beam. For inspecting surface with a pattern thereon, the light from the surface is first passed through a spatial filter before it is imaged onto the charge-coupled devices. The spatial filter includes stripes of scattering regions that shift in synchronism with relative motion between the beam and the surface to block Fourier components from the pattern. The spatial filter may be replaced by reflective strips that selectively reflects scattered radiation to the detector, where the reflective strips also shifts in synchronism with the relative motion.