Patent ID: 7982882
Filing Date: 2011-07-19
Classification: G01B,G01M

Abstract:
1. An optical wave interference measuring apparatus for measuring the shape of a rotationally symmetric test surface of a test object arranged on a measurement optical axis, comprising: a test surface position adjusting unit that sequentially changes the position of the test surface relative to the measurement optical axis from a reference position where a surface central axis of the test surface is aligned with the measurement optical axis such that an intersection between the measurement optical axis and the test surface is sequentially moved to a plurality of annular regions obtained by dividing the test surface in a diametric direction in a virtual plane including the measurement optical axis and the surface central axis and the measurement optical axis is perpendicular to the tangent plane of the test surface at the intersection whenever the intersection is moved; a test surface rotating unit that rotates the test surface on a rotation axis with the surface central axis aligned with the rotation axis, whenever the relative position is changed; a microscopic interference optical system that radiates low-coherence measurement light which travels along the measurement optical axis while converging to the rotating test surface and mixes reference light and returning light of the measurement light from a focusing region of the test surface to obtain interference light; an imaging system for image capture during rotation that captures the interference light at a plurality of rotational positions of the rotating test surface and uses a one-dimensional image sensor to capture an interference fringe at each rotational position which corresponds to an intersection region between the virtual plane and the test surface in each of the plurality of annular regions; and a shape analyzing unit that calculates shape information of each of the plurality of annular regions on the basis of the interference fringe at each rotational position and connects the shape information of each of the annular regions to calculate shape information of the entire combined region of the plurality of annular regions.