Patent ID: 7623251

Claim:
A system for determining at least one geometric characteristic of an object having a first surface and a second surface, wherein at least one of the first and second surfaces passes a substantial amount of light therethrough, the system comprising: a light source adapted to illuminate the object; an optical element adapted to receive light from the first and second surfaces of the object and to produce a first light beam corresponding to light from the first surface of the object and a second light beam corresponding to light from the second surface of the object; a light intensity detector having a radiation sensitive surface adapted to receive the first and second light beams and to detect the intensity of incident radiation on the radiation sensitive surface from the first and second light beams, and to produce an output that provides a measure of the intensity of the incident radiation; a translator adapted to adjust relative positions of the optical element and the light intensity detector; and a processor adapted to determine wavefronts of the light from the first and second surfaces based on the output of the light intensity detector at a plurality of different relative positions.