Optical entire-circumference encoder and motor system

摘要

An optical entire-circumference encoder has: a plurality of rotation slits formed at an equal pitch radially around the rotation axis as a center in a rotation track and transmitting light; a plurality of fixed slits formed at an equal pitch in the regions radially around the rotation axis as a center in the fixed track and transmitting light; and two or more light receivers disposed in a vicinity of the rotation axis and receiving the light guided by a light guiding unit in the two or more regions. The plurality of fixed slits in one of the regions and the plurality of fixed slits in another region adjacent to the one region are formed so that a phase difference by which a rotation direction is determined occurs between light reception signals of the two or more light receivers.