MOTOR CHANGEABLE TO STEP DRIVING AND BRUSHLESS DRIVING AND LENS BARREL CONTAINING SAID MOTOR

摘要

PURPOSE:To drive efficiently a lens to the focal position by providing both of a part operating as a brushless motor and a part operating as a step motor in one lens driving device. CONSTITUTION:A hollow cylindrical type permanent magnet 1 is held freely rotatably by means of a bearing 9a in the stationary barrel of a lens barrel. A lens L1 for focusing is fixed to the magnet 1 and multiple poles are magnetized on one end side in the direction along the optical axis of the lens L1 so that S poles and N poles function as a step motor. The other end side of the magnet 1 is acted as a rotor for the permanent magnet part for brushless driving. A coil 2 for the step motor and coils 4A, 4B for the brushless motor are disposed on the outside of the magnet 1.