Rotary reciprocating drive actuator with movable element and magnets and rotating mirror

A rotary reciprocating drive actuator comprising:

• a movable member including a shaft to which a movable object is connected and a movable magnet fixed to the shaft;
• a fixing body including coils and a core, the core including even-numbered core parts and even-numbered magnetic poles, the even-numbered core parts around which the coils are respectively wound, arranged parallel to each other so as to sandwich the movable magnet in a direction perpendicular to a rotation axis of the shaft, the fixing body being configured to rotatably support the shaft, the rotary reciprocating drive actuator being configured to use electromagnetic interaction between the coils that is energized and the movable magnet to drive the movable member into reciprocating rotation about the shaft with respect to the fixing body,
• wherein the movable magnet has a ring shape with even-numbered magnetic poles alternately magnetized in an S pole and an N pole at an outer periphery of the shaft,
• wherein the number of the even-numbered magnetic poles of the core and the number of the even-numbered magnetic poles of the movable magnet are equal to each other,
• wherein the even-numbered magnetic poles of the core are disposed opposite to the movable magnet at an outer periphery side of the shaft with an air gap between the even-numbered magnetic poles of the core and the movable magnet,
• wherein the fixing body includes a rotation angle position holding part disposed opposite to the movable magnet with an air gap between the rotation angle position holding part and the movable magnet, the rotation angle position holding part being configured to use a magnetic attractive force generated between the rotation angle position holding part and the movable magnet to hold a rotation angle position of the movable magnet, and
• wherein the coils that are parallel and the rotation angle position holding part are arranged to surround the movable member in a plane orthogonal to the rotation axis.