OPTICAL ENCODER

摘要

Provided is an optical encoder capable of improving the precision of an insertion angle in a single signal track, in an encoder of sine-wave angle insertion type.  The optical encoder includes a waveform, in which a phase-modulated wave is superimposed in a predetermined period over a sine-wave of a fundamental period, as a signal track (103), and an optical detector (104) for extracting the sine signal and the cosine signal of the phase-modulated wave.  An operation unit (106) operates electric angles individually from the output signals of a first optical detector and a second optical detector belonging to the optical detector, and determines the sum and difference of the electric angles, thereby acquiring the electric angle and the phase-modulated wave of the fundamental period.