Patent ID: 7737604
Filing Date: 2010-06-15
Classification: H01L,H02N

Abstract:
1. An ultrasonic actuator comprising: an actuator body for performing vibration, the actuator body including a piezoelectric element; a control section for setting a driving frequency of a driving voltage to be applied to the actuator body; a power supply section for applying the driving voltage having the driving frequency set in the control section to the actuator body; and a memory section for storing data related to a difference between an antiresonance frequency and a resonance frequency of the piezoelectric element, wherein the control section determines, based on a reference frequency at which a current value of a current fed to the piezoelectric element is local minimum and the data related to the difference between the antiresonance frequency and the resonance frequency of the piezoelectric element and stored in the memory section, a control range of the driving frequency so that a lower limit of the control range is equal to or higher than a frequency at which the current value of the current fed to the piezoelectric element is local maximum and sets the driving frequency to a value in the control range.