Patent ID: 7239052

Claim:
A magnetic actuator adopted to be used with an iris diaphragm, comprising: a yoke, comprising a first opening and a second opening, a frame encircling the first opening and the second opening, and a path located between the first opening and the second opening; a first magnet, disposed in the first opening; a second magnet, disposed in the second opening; a coil surrounding the path; a light shield, connected to a first end of the coil; and a guiding element, disposed outside the path and connected to the coil, wherein when a current passes through the coil, the coil reciprocates by a magnetic induction between the first magnet and the second magnet such that the iris diaphragm is adjustable by the light shield; and when there is no current through the coil, a dynamic force produced by the guiding element returns the light shield to an original position wherein the guiding element is a third magnet, producing the dynamic force by magnetic induction of the path to return the light shield to the original position.