| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a piezoelectric actuator whose driving can be easily controlled. <P>SOLUTION: The piezoelectric actuator 20 is capable of driving a rotor both in a positive direction and in a negative direction by changing the plus and the minus of the phase difference (driving phase difference) between driving signals D1, D2 input to first and second vibrational regions R1, R2. The state of vibration is detected by a detection electrode (261 or 262) provided in at least either of the first vibrational region R1 and the second vibrational region R2 where a phase delay driving signal is supplied. Driving is controlled based on the phase difference (detection phase difference) of this vibration signal (S1 or S2) from the driving signal D1. Therefore, a phase difference characteristic that causes monotonic increase or monotonic decrease can be obtained. Since driving can be controlled using this detection phase difference as a set value for drive control, any complicated algorithm is not necessary. As a result, the scale of circuitry is not increased and the frequency of driving signals can be easily controlled. <P>COPYRIGHT: (C)2007,JPO&INPIT |
