| 摘要 |
PROBLEM TO BE SOLVED: To prevent destruction and change of capacity even if rapid acceleration due to impact or the like is applied. SOLUTION: The device has a piezoelectric driving part 1 of an MEMS structure whose one end side is fixed, and the other end side can be moved up and down by expansion and contraction of a piezoelectric film; fixed electrodes 3a, 3b which are disposed opposed in the other end side of the piezoelectric driving part 1 across a dielectric film 2, and a control circuit unit (driving control unit) 4 which controls driving of the piezoelectric driving part 1. Since the capacity of a variable capacity element 20 provided to the other end side of the piezoelectric driving part 1 is detected by the control circuit unit 4, and a voltage applied to first and second piezoelectric films 6, 7 is subjected to feedback control to always keep the capacity constant; it is possible to restrain capacity variation of the variable capacity element 20, and to obtain manufacturing yield exceeding about 95%. COPYRIGHT: (C)2008,JPO&INPIT
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