The paper discusses some optical methods of measuring the profile of disk non-contacting. Grazing incident interferometer, Color schieren, and Moire deflectometer. Especially in the paper a new measuring method and instrument is introduced which is a pointwise instrument with an optical probe. It can measure a global and local profile of a disk in tangential and radial direction at the same time, without sacrificing the measurement accuracy. The resolution of the probe is 0.3 nm, the instrument accuracy better than 0.04 micrometers , the dynamic range larger than 5 mm.
|