SHAPE EVALUATING APPARATUS.

摘要

A shape evaluating apparatus for accurately evaluating the shape of an aspherical lens in a noncontacting manner utilizing the interference of light. The reflected light from an object (26) is reflected on the reflecting surfaces of a beam splitter (27) and a reflector (28), which are disposed in opposition to each other, to generate two laterally-shifted optical beams. According to the above-described arrangement, the two laterally-shifted optical beams passed through the common optical path, so that the optical beams can be kept stable with respect to the variations of the environment. Since the construction of the apparatus is simplified, the set-up cost can be advantageously reduced.