PERFECCIONAMIENTOS EN UN DISPOSITIVO PARA LA DETECCION DE FALLOS SUPERFICIALES.

摘要

A fault detecting apparatus for flat articles generates a line of light on the article which is imaged onto a photoreceiver via an optical system having cylindrical imaging characteristics. For use with an article 11 having light diffracting characteristics the line of light 12 is arranged substantially at right angles to the structure 13 which causes the light diffraction. The optical system 14 having cylindrical imaging characteristics detects, apart from the zero order at least also the first diffraction order of the light leaving the article. The light of the first diffraction order is also imaged onto its own photoreceiver (FIG. 1).