Patent ID: 7268887
Filing Date: 2007-09-11
Classification: G01B

Abstract:
1. An interferometric system for measuring opposite side surfaces of opaque parts both individually and with respect to each other, comprising: a first interferometer having a first reference surface; a second interferometer having a second reference surface; the first and second reference surfaces being located within a field of view of at least the first of the interferometers; the first interferometer being positioned for measuring unambiguous distances between corresponding points on a first side of the opaque parts and the first reference surface; the second interferometer being positioned for measuring unambiguous distances between corresponding points on a second side of the opaque parts and the second reference surface; the first interferometer also being positioned for measuring unambiguous distances between corresponding points on the first and second reference surfaces; and a processor that relates the relative measurements of the first and second sides of the opaque parts with respect to each other based on the measurement of the unambiguous distances between the reference surfaces and calculates unambiguous distances between the corresponding points on the first and second sides of the opaque parts.