Patent ID: 6966118

Claim:
An absolute angle detecting device, comprising: a rotary disk being rotatably supported; a first code pattern row and a second code pattern row, each provided on the circumference whose center is the center of rotation of the rotary disk; a first detecting element group consisting of a plurality of detecting elements that is arranged at equal intervals opposite to the first code pattern row, a second detecting element group consisting of a plurality of detecting elements that is arranged at equal intervals opposite to the second code pattern row, and converting means for respectively converting a plurality of codes supplied from the first detecting element group and a plurality of codes supplied from the second detecting element group into rotation angles for the rotary disk, wherein both a gray code obtained by combining the plurality of codes supplied from the first detecting element group and a gray code obtained by combining the plurality of codes supplied from the second detecting element group are a cyclic code in which a digit place is moved one by one whenever the rotary disk is rotated by a unit angle that is set with respect to the first code pattern row or the second code pattern row.