| 摘要 |
A movable plate 21 is fastened to a substrate 11 via flexure parts 27 a and 27 b, and can move upward and downward with respect to the substrate 11 . The substrate 11 also serves as a fixed electrode. The movable plate 21 has second electrode parts 23 a and 23 b which can generate an electrostatic force between these electrode parts and the substrate 11 by means of a voltage that is applied across these electrode parts and the substrate 11 , and a current path 25 which is disposed in a magnetic field, and which generates a Lorentz force when powered. A mirror 12 which advances into and withdraws from the optical path is disposed on the movable plate 21 . When the movable plate 21 is caused to move from the lower position in which the electrostatic force is increased to the upper position, the control part controls the current so that the Lorentz force is generated in a downward orientation and gradually decreases while the movable plate 21 is moving from an intermediate position to the upper position. As a result, the mobility range of the movable part can be expanded without applying a high voltage or sacrificing compact size, and the power consumption can be reduced; furthermore, the reliability in the case of long-term operation can be increased.
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