Patent ID: 7224467
Filing Date: 2007-05-29
Classification: G01B,G01D,G01S

Abstract:
1. An apparatus for use in rotational measurement, comprising: a rotational assembly to rotate about a rotational axis; at least two interferometers, each to receive a respective light beam, to separate said respective light beam into both a respective reference beam and a respective measuring beam, to direct said respective measuring beam to said rotational assembly, and to receive said respective measuring beam back from said rotational assembly; said rotational assembly including a plurality of cube corners mounted such that at least one of said cube corners is able to receive from and reflect back to one said interferometer a respective said measuring beam as said rotational assembly rotates about said rotational axis; and said interferometers each further to combine its said respective reference beam with its said respective measuring beam into a respective detection beam, wherein at least one said respective detection beam includes an interference signal; thereby permitting rotational measurement of said rotational assembly and any attached work piece target based on processing of said interference signal.