| 摘要 |
PROBLEM TO BE SOLVED: To provide a drive mechanism using an electromechanical transducer whose driving efficiency is good at a desired drive speed. SOLUTION: In a drive mechanism, drive pulses are supplied to a piezoelectric element so as to generate an expansion and contraction displacement, and a member, to be driven, which is frictionally coupled to a driving shaft fixed to the piezoelectric element is driven. In the drive mechanism, the piezoelectric element 28 is divided into a plurality of blocks 28a, to 28d whose laminated numbers are different, and the blocks are connected to constant-current drive circuits 25a to 25d via switching elements 27a to 27d. The constant-current drive circuits are formed with an optimum circuit configuration, according to the difference in impedances between the piezoelectric-element blocks 28a to 28d. Since the piezoelectric-element blocks, which are selected according to a driving speed, are driven by the constant-current drive circuits which are suitable for the selected piezoelectric-element blocks, they can be driven with good efficiency and at a desired drive speed. |
