Patent ID: 6771375
Filing Date: 2004-08-03
Classification: G01B

Abstract:
An interferometric method for measuring rotationally and non-rotationally symmetric optics, said interferometric method comprising the steps of:aligning a test optic to be measured and at least one aspheric reference surface placed closely adjacent the test optic by a predetermined distance; illuminating said at least one aspheric reference surface with a beam having a predetermined wavefront such that part of said predetermined wavefront is reflected from said aspheric reference surface to serve as a reference wavefront and part is transmitted as a continuing aspherical wavefront whose shape changes as it propagates across said predetermined distance such that it impinges on the said test optic with a shape that substantially conforms to the anticipated shape of said test optic and returns therefrom as a measurement wavefront that travels back towards said aspheric reference surface; and combining said reference and measurement wavefronts to form an interferogram containing phase information indicative of the shape of the wavefront generated by the test optic.