Device for detecting a centring error.

摘要

A device for detecting a centring error of a rotationally symmetrical surface (01, 02) of an object (0) with respect to a rotational axis (AR) about which axis the object is rotated for the purpose of the centring error detection is described. Two beams (b1, b2; b3, b4) at angles of approximately 90 DEG are directed onto the object and the variation in the phase difference caused by the centring error ( epsilon ) between the two beams (b1 b2; b3, b4) reflected by the surface is determined.