Patent ID: 6819434
Filing Date: 2004-11-16
Classification: G01B

Abstract:
An apparatus comprising:a multi-axis interferometer for measuring changes in a position of a measurement object, the interferometer is configured to receive a progenitor input beam, direct a first angle-measuring beam derived from the progenitor input beam to make a pass to a first point on the measurement object, direct a second angle-measuring beam derived from the progenitor input beam to make a pass to a second point on the measurement object, and then combine the angle-measuring beams to produce an angle-measuring output beam, wherein each angle-measuring beam makes only a single pass to the measurement object before being combined to form the angle-measuring output beam, and the interferometer is further configured to direct another set of beams derived from the progenitor input beam along respective paths and then combine them to produce another output beam comprising information about changes in the position of the measurement object.