Patent ID: 7218018

Claim:
An actuator comprising: a casing; a stationary member which has a coil member and is mounted in the casing; and a movable member which includes a moving element and is supported by the casing; wherein the moving element has a shaft and is supported by the casing so as to be moved in an axial direction of the shaft and in a rotational direction having the axial direction of the shaft as its rotational axis; wherein electric current is caused to flow through the coil member such that the moving element is moved in the axial direction and in the rotational direction; wherein the stationary member includes a first stationary member that imparts to the movable member a force oriented in the axial direction and a second stationary member that imparts to the movable member a force oriented in the rotational direction; wherein the first stationary member includes a pair of first stationary elements provided symmetrically with respect to the rotational axis and the second stationary member includes a pair of second stationary elements provided symmetrically with respect to the rotational axis; wherein the coil member includes a first coil member that excites a first magnetic path passing through the first stationary member and a second coil member that excites a second magnetic path passing through the second stationary member; wherein the first stationary member imparts to the moving element the force oriented in the axial direction and the second stationary member imparts to the moving element the force oriented in the rotational direction; wherein the moving element includes a magnet member having a magnetization direction substantially orthogonal to the axial direction; wherein the first coil member includes a pair of first coils each provided in each of the first stationary elements and the second coil member includes a pair of second coils each provided in each of the second stationary elements; and wherein the first coils excite the first stationary elements in an antiphase excitation mode, respectively and the second coils excite the second stationary elements in an antiphase excitation mode, respectively.