| 摘要 |
PURPOSE: To decide efficient drive frequency range, in a driver using an electromechanical converting element. CONSTITUTION: A drive shaft 11 is reciprocated axially by a piezoelectric element 18. The slider block 12a of a lens retaining frame pierces the drive shaft 11, and a pad 16 pressure-contacts with the drive shaft 11 by a spring 17, and the drive shaft 11 and the slider block 12a are frictionally coupled with each other. When saw-toothed wave drive pulses are applied to the piezoelectric element 18, the drive shaft 11 is dislocated at different reciprocation speed in axial direction, and the slider block 12a shifts in the direction of an arrow a, too. The slider block 12a (shifting member) can be driven at high speed efficiently by setting the drive frequency f of the piezoelectric element such that f1/3<=f<=2f1/3, for the common frequency f1 of the piezoelectric element (electromechanical converting element). |
