Oblique Incidence Interferometer

摘要

An oblique incidence interferometer 1 includes a light source 11 for emitting coherent light in an oblique direction to a measurement object W; a light collimating unit 12 for collimating the coherent light from the light source 11; a beam dividing unit 14 for dividing the collimated beam from the light collimating unit 12 into a measurement beam and a reference beam; a beam combining unit 15 for combining the measurement beam reflected by the measurement object W with the reference beam; and an image pickup device 17 for picking up images of interference fringes representing a surface shape of the measurement object, wherein the oblique incidence interferometer 1 includes measurement range expanding means 10 for enlarging a light measurement range on the measurement object W in a lateral direction of the measurement range.