Rotational precision measuring device

Abstract

To provide a rotational precision measuring device that can improve the efficiency of measurement work. [Solution] The system includes a reference sphere 22 that is rotatable integrally with the work chuck 100 and whose center C is located on the rotation axis P of the work chuck 100; an optical interferometer 14 that splits a laser beam into a measurement beam and a reference beam, emits the measurement beam toward the reference sphere 22, and detects an interference signal indicating the intensity of the interference light between the reflected measurement beam and the reference beam reflected from the surface 22A of the reference sphere 22; a focusing lens 16 positioned in the optical path of the measurement beam and focusing the measurement beam toward the center C of the reference sphere 22; and a computer 20 that detects rotational runout information indicating the rotational runout of the work chuck 100 from the interference signal obtained by the optical interferometer 14 when the measurement beam is irradiated onto the reference sphere 22 while the reference sphere 22 is rotated integrally with the work chuck 100.

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