Optical wave interference measuring apparatus

摘要

Disclosed is an optical wave interference measuring apparatus capable of accurately measuring the shape of a small test surface that is rotationally symmetric and has a complicated shape. The relative position of a test surface 80 is sequentially changed from a reference position where a surface central axis C is aligned with a measurement optical axis L such that the measurement optical axis L is sequentially moved to a plurality of annular regions obtained by dividing the test surface 80 in a diametric direction. The test surface 80 is rotated on a rotation axis whenever the relative position is changed. Measurement light that travels while being converged by a Mirau objective interference optical system 23 is radiated to the rotating test surface 80, and a one-dimensional image sensor 32 captures interference fringes at each of a plurality of rotational positions. The shape information of each annular region is calculated on the basis of the captured interference fringes at each rotational position, and the shape information is connected to calculate the shape information of the entire measurement region.