Displacement interferometer, for use in displacement interferometer system, has displacement converter for transforming displacement perpendicular to progressing direction of measuring beam into path difference of measuring beam

摘要

Displacement interferometer has a light source for generating a light beam, and a beam splitter (111) for dividing the light beam into a reference beam and a measuring beam. A displacement converter (121) alters a progressing direction of the measuring beam, and transforms a displacement perpendicular to the progressing direction of the measuring beam into a path difference of the measuring beam. Independent claims are included for; (i) A displacement interferometer system, comprising a light source for generating a light beam; and (ii) An exposure system including two of the above interferometers.