Optical movement information detector, movement information detection system, electronic equipment and encoder

Abstract

Two different phase components obtained by splitting interference light of light from an object by a diffraction grating are guided to first and second PD's by a second optical system. A first signal is outputted from a first signal processing circuit section that receives light reception signal from first PD, and a second signal is outputted from a second signal processing circuit section that receives a light reception signal from the second PD. A third signal of an interference light signal whose noise component is removed is outputted by a third signal processing circuit section using the first signal and the second signal. Then, the frequency of the third signal is detected, and the movement velocity of the object is detected by a movement velocity detection section on the basis of the frequency.