Patent ID: 6785974
Filing Date: 2004-09-07
Classification: G01D

Abstract:
A rotation angle detecting device comprising:a cylindrical code plate that rotates as a rotary body rotates, the code plate having a circumferential side portion that is provided with two slit arrays that are arranged along a rotation axis of the code plate, each of the slit arrays having slits that are arranged in a circumferential direction of the code plate; a light-emitting portion provided at a prescribed position for each of the slit arrays, for emitting light toward a slit of the slit array; and a light-receiving portion provided for each of the slit arrays, for receiving the light that has been emitted by the light-emitting portion and has passed through the slit, wherein the slits of one of the two slit arrays are cuts that are formed at one end of the circumferential side portion so as to extend along the rotation axis of the code plate, and the slits of the other slit array are cuts that are formed at the other end of the circumferential side portion so as to extend along the rotation axis of the code plate.