DIFFRACTION GRATING REVOLVING LASER OPTICAL ENCODER

摘要

PROBLEM TO BE SOLVED: To clearly facilitate mounting a laser optical encoder and a diffraction grating owning to elevation of the allowable error by an optical Fourier transform degree system action and send out high quality optical signals by a high speed operation of this optical system even when unexpected relative error occurs by the grating vibration. SOLUTION: Based on a special layout system of optical elements, two lights are incident to arrive at the same point on a grating, the system survey performance greatly reduces the sensitivity to the inexactness of fixing the position between a movable grating and a stationary unit of the laser optical encoder on an optical head. This effect of reducing the sensitivity can be attained by generating an optical degree system of Fourier transformation with a combination of a focusing lens 708 with a right prism 709.