| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a drive device which requires small power consumption and has small operation sounds. <P>SOLUTION: The drive device includes an electro-mechanical conversion element that expands and contracts when voltage is applied, a vibration member that is reciprocatingly displaced by the expansion and contraction of a piezoelectric element with one end of the vibration member fixed to the electro-mechanical conversion element, a friction engaged member that is friction-engaged with the vibration member, and a drive circuit that applies a periodically fluctuating drive voltage to the piezoelectric element. The drive circuit changes the frequency of the drive voltage within a range higher than a predetermined lower limit frequency and higher than an audible frequency corresponding to the speed for displacing the friction-engaged member, and when the frequency of the drive voltage is the lower limit frequency, the waveform of the drive voltage is changed according to the speed for displacing the friction-engaged member. <P>COPYRIGHT: (C)2010,JPO&INPIT |
