Patent ID: 7667852
Filing Date: 2010-02-23
Classification: G01B

Abstract:
1. A method for obtaining at least one of shape, thickness, and inhomogeneity of an object having first and second opposing surfaces, the method comprising: providing an interferometer comprising: receiving an object into the cavity such that the first surface of the object is facing the first reference surface and the second surface of the object is facing the second reference surface, where an optical path remains unobstructed by the object between the first reference surface and the second reference surface; directing a light into the interferometer through only the first reference surface, such that the light produces; contemporaneously recording multiple interferograms generated by phase differences in the reflected lights; separating the contemporaneously recorded interferograms into individual interferograms, including; computing a height of the first surface of the object from the phase differences of the A interferogram; computing a height of the second surface of the object from the phase differences of the B interferogram; computing a thickness of the object from subtracting a sum of the phase differences of the A interferogram and the phase differences of the B interferogram from the phase differences of the C interferogram; and computing a material inhomogeneity of the object by subtracting the phase differences of the C interferogram from the sum of the phase differences of the A interferogram, the phase differences of the B interferogram, and the phase differences of the T interferogram.