ENCODER AND ROTATIONAL INFORMATION DETECTING METHOD

摘要

PROBLEM TO BE SOLVED: To reduce the cost and the size of an encoder detecting rotational information of a rotator. SOLUTION: A plurality of slits 103 are arranged at various intervals in the circumferencial direction of a rotator 104 which is rotated by using a shaft 101 as the center. Rotational speed information is obtained by comparing magnification of time between specified trailing edges of an outputted voltage signal from a photo interruptor 102 and previously memorized time. Rotational direction information is obtained by comparing the pattern of the outputted voltage signal with a previously memorized pattern.