APPARATUS AND METHODS FOR SURFACE CONTOUR MEASUREMENT

摘要

Apparatus and methods of measuring position information, typically the depth coordinate, of a point on the surface of an object. In one embodiment, the apparatus includes two sources of radiation (P1, P2) positioned to illuminate the point (P0) on the surface of the object (10) with radiation from each of the sources. The radiation from each of the sources is coherent with respect to the radiation from the other source. A control system (32) changes the phase of the radiation from at least one of the sources relative to the phase of the radiation from the other source as measured at the point on the surface of the object. A detector (22) is positioned to receive radiation scattered by the point and a processor (28), in communication with the detector, calculates position information in response to the change in phase of the radiation from the source and the received radiation scattered by the point on the surface of the object.