US 7,119,475 B2 · Driving method of piezoelectric actuator, driving apparatus of piezoelectric actuator, electronic watch, electronics, control program of piezoelectric actuator, and storage medium

Abstract

A drive device for a piezoelectric actuator, wherein the time needed to achieve highly efficient drive conditions is shortened to reduce power consumption, and stabilized control can be performed. The device has a phase difference detection device (phase difference/voltage conversion circuit (51)) for detecting detection signals of longitudinal oscillation and bending oscillation from an oscillator (5) and detecting the phase difference between these two signals, frequency control devices (52 to 56) for comparing the phase difference detected by the phase difference detection device with a standard phase difference value and controlling the frequency of a drive signal sent to a piezoelectric element (17) on the basis of the results of this comparison, and an amplitude detection device (amplitude detection circuit (57)) for detecting the amplitude of the detection signal of the piezoelectric element (17). The frequency control device compares the amplitude with a standard amplitude value and controls the frequency of the drive signal on the basis of the results of this comparison.

Claims27

Dependent claims

A drive method for a piezoelectric actuator comprising:

preparing the piezoelectric actuator having an oscillator being configured to oscillate due to the supply of a drive signal with a specific frequency to a piezoelectric element, and contact sections being convexities being provided on opposite sides of the oscillator and being configured to contact a driven object;
detecting a first detection signal indicating an oscillating state of the oscillator and controlling a frequency of the drive signal sent to the piezoelectric element based on the first detection signal and the drive signal, or based on the first detection signal;
detecting the amplitude of the first detection signal;
comparing the amplitude and a standard amplitude value of the first detection signal;
and
controlling the frequency of the drive signal based on the results of comparing the amplitude and the standard amplitude value of the first detection signal.

3 more elements

A piezoelectric actuator comprising:

a piezoelectric element having an oscillator;
and
a drive device being configured to supply a drive signal with a specific frequency to the piezoelectric element to oscillate the oscillator, the drive device having
a frequency control device being configured to control the frequency of the drive signal, and
an amplitude detection circuit being configured to detect the amplitude of a detection signal,
the frequency control device including
a frequency increase/decrease control device controlling the increase or decrease in the frequency of the drive signal, and
a frequency increase/decrease rate control device controlling the rate of change of the increase or decrease in the frequency of the drive signal,
either one of the frequency increase/decrease control device or frequency increase/decrease rate control device detecting a detection signal indicating the oscillating state of the oscillator and controlling the frequency of the drive signal on the basis of the detection signal and the drive signal, or on the basis of the detection signal, and
the other one of the frequency increase/decrease control device or frequency increase/decrease rate control device comparing the amplitude and the standard amplitude value and controlling the frequency of the drive signal on the basis of the results of this comparison.

7 more elements

A piezoelectric actuator comprising:

a piezoelectric element having an oscillator;
and
a drive device being configured to supply a drive signal with a specific frequency to the piezoelectric element to oscillate the oscillator, the drive device having
a frequency control device being configured to control the frequency of the drive signal, and
an amplitude detection circuit being configured to detect the amplitude of a detection signal, and
the frequency control device being configured to detect a detection signal indicating the oscillating state of the oscillator and to control the frequency of the drive signal based on results of comparing the amplitude of the detection signal and a standard amplitude value,
the frequency control device including
a constant voltage circuit outputting a standard voltage for phase difference comparison and a standard voltage for amplitude detection,
a comparison circuit being configured to compare the standard voltage for phase difference comparison outputted by the constant voltage circuit with a phase difference voltage outputted from a phase difference/voltage conversion circuit, and to output a comparison result signal, and
a drive control section being configured to receive the comparison result signal outputted by the comparison circuit and to control the frequency of the drive signal sent to the piezoelectric element,
the amplitude detection circuit being configured to detect amplitude by comparing the standard voltage for amplitude detection outputted by the constant voltage circuit with the detection signal, and
the drive control section having functions to decrease the rate of change in frequency over a specific period of time when the amplitude detection voltage detected by the amplitude detection circuit is equal to or greater than the standard voltage for amplitude detection, and to increase the rate of change in frequency over a specific period of time when the amplitude detection voltage detected by the amplitude detection circuit is less than the standard voltage for amplitude detection.

9 more elements

A drive method for a piezoelectric actuator comprising:

supplying a drive signal with a specific frequency to a piezoelectric element to oscillate an oscillator of the piezoelectric element by a drive device;
controlling the frequency of the drive signal by a frequency control device of the drive device;
detecting the amplitude of a detection signal by an amplitude detection circuit of the drive device;
detecting a detection signal indicating the oscillating state of the oscillator and controlling the frequency of the drive signal based on results of comparing the amplitude of the detection signal and a standard amplitude value by the frequency control device;
outputting a standard voltage for phase difference comparison and a standard voltage for amplitude detection by a constant voltage circuit of the frequency control device;
comparing the standard voltage for phase difference comparison outputted by the constant voltage circuit with a phase difference voltage outputted from a phase difference/voltage conversion circuit, and outputting a comparison result signal by a comparison circuit of the frequency control device;
receiving the comparison result signal outputted by the comparison circuit and controlling the frequency of the drive signal sent to the piezoelectric element by a drive control section of the frequency control device;
detecting amplitude by comparing the standard voltage for amplitude detection outputted by the constant voltage circuit with the detection signal by the amplitude detection circuit by the amplitude detection circuit;
and
decreasing the rate of change in frequency over a specific period of time when the amplitude detection voltage detected by the amplitude detection circuit is equal to or greater than the standard voltage for amplitude detection, and increasing the rate of change in frequency over a specific period of time when the amplitude detection voltage detected by the amplitude detection circuit is less than the standard voltage for amplitude detection by the drive control section.

7 more elements

Dependencies are inferred from the claim text.

Driving method of piezoelectric actuator, driving apparatus of piezoelectric actuator, electronic watch, electronics, control program of piezoelectric actuator, and storage medium

Life of this patent

Driving method of piezoelectric actuator, driving apparatus of piezoelectric actuator, electronic watch, electronics, control program of piezoelectric actuator, and storage medium

Life of this patent

Abstract

Claims27