| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize a piezoelectric actuator which achieves a small size and light weight, suppresses the temperature rise, and stably drives. <P>SOLUTION: A piezoelectric actuator 100 includes: a rectangular vibrator 1 including a piezoelectric element 11; a drive circuit 26 supplying a drive signal to the piezoelectric element 11; a phase difference detection circuit 27 detecting a phase difference between the drive signal and a detection signal detected on the basis of vibrations of the vibrator 1; and a frequency controller 20 controlling the frequency of the drive signal and electric power. The frequency controller 20 changes the frequency. When the phase difference is in a predetermined range, the frequency controller 20 stores a value of the frequency as a first frequency storage value, sets a voltage to an upper limit voltage value, and performs controlling to adjust the frequency and maintain the phase difference in the predetermined range. When the frequency changes from the first frequency storage value and exceeds a first value which is preset on the basis of the temperature characteristics of the resonance frequency of the vibrator 1, the frequency controller 20 stores a value of the frequency as a second frequency storage value and sets the voltage to a lower limit voltage value which is smaller than the upper limit voltage value. <P>COPYRIGHT: (C)2013,JPO&INPIT |
