Defect detecting device for two-layer parts, in particular for solar cells

Abstract

A defect detecting device for checking by light reflection parts constituted by a substrate covered with a clear coat. The device includes a reference surface wherein the inspected parts are located; a polychromatic spotlight whose light beam direction intercepts the flat reference surface in an observation area, the light beam direction forming an angle larger than .pi.-.beta., where .beta. is the BREWSTER angle, with the flat reference surface; a viewing apparatus whose optical axis is in the same plane as the light beam direction, the axis forming an angle larger than .pi.-.beta. with the flat reference surface; at least a first secondary source of monochromatic light, located next to the viewing apparatus and orientated with a secondary light axis intercepting the observation area; a carriage carrying the spotlight and the viewing apparatus and the secondary source, and a device for controlling the relative displacement of the carriage with respect to the flat reference surface, in parallel with at least two scanning directions parallel to the flat reference surface.

Dependencies are inferred from the claim text.