ALIGNMENT OPTICAL SYSTEM FOR INTERFEROMETER AND DEVICE USING IT

摘要

PROBLEM TO BE SOLVED: To easily carry out, whenever necessary, alignment of a surface for inspection in an oblique-incidence interferometer device by disposing a screen over the focal plane of an image forming lens on which a light beam reflected once by each of the surface for inspection and a reference plane and another light beam transmitted through the reference plane enter, and adjusting the inclination of the surface for inspection so that two spots formed on the screen coincide with each other. SOLUTION: The light beam 21a reflected by the surface 2a for inspection and reflected again by the reference plane 16a and another light beam 22a incident parallel reference plate 16 and directly transmitted through the reference plane 16a are both made incident on the image forming lens 22, and the two spots formed by the light beams are formed on the screen 18 disposed to coincide with the focal plane of the image forming lens. Alignment of the surface for inspection is adjusted based on the positional relationship between the two spots.