Patent ID: 7532005

Claim:
A rotation angle detection apparatus comprising: a main rotatable body; a first sub rotatable body and a second sub rotatable body which are rotated in a linked motion with a rotation of the main body, and are overlapped with each other; an angle detection part for detecting a rotation angle of the first sub rotatable body; a phase difference detection part for detecting a phase difference between a rotation of the first sub rotatable body and a rotation of the second sub rotatable body; and a control circuit for carrying out processing of a signal transmitted from the angle detection part and a signal transmitted from the phase difference detection part, and calculating a rotation angle of the main rotatable body; wherein the angle detection part comprises a magnet attached to the first sub rotatable body, and a first magnetic sensor facing the magnet; and wherein the phase difference detection part comprises the magnet, and a second magnetic sensor attached to the second sub rotatable body and facing the magnet.