HUP0103248A2 - Optical image forming inspection apparatus with divergent illumination - Google Patents

Abstract

An optical test unit making use of divergent polarized, non polarized (white) or monochromatic light, renders rapid, non-destructive qualifying investigations of large extended surfaces possible. Characteristically, illumination of test-samples is carried out with divergent light emanating from a real or virtual pinhole sources, instead of with conventional parallel or focussed beams of light. Images formed in this manner (opt. passed through a spectral dispersing device, as a prism, or a lattice) are fixed on position sensing photodetectors. In case of a simplified version of a test-unit the point source (1) provides the divergent light (2), that is passed through a polarizer (3) to reach the sample (4). Divergent light (2) reflected back from the surface of a sample reaches the system of position sensing photodetectors (6) through an analyzer (5). In this particular case the detector (6) is a CCD* matrix. The sample (4) may be displaced in its own plane, at least along a single line, so, that all points along this line, get at least once into a position where they can be illuminated by all values of angles appertaining to the domain of the divergent beam.