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US 2002/0171410 A1Published application
Piezoactuator and drive circuit therefor
AssigneeSeiko Epson Corporation
InventorsHidehiro Akahane, Akihiro Sawada, Makoto Furuhata
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AssigneeSeiko Epson Corporation
InventorsHidehiro Akahane, Akihiro Sawada, Makoto Furuhata
Estimating the term…
A piezoactuator has a diaphragm, and the diaphragm has flat piezoelectric elements that oscillate in a longitudinal oscillation mode and a sinusoidal oscillation mode. A first electrode for detecting oscillation in the longitudinal oscillation mode, and a second electrode for detecting the amplitude of oscillation in the sinusoidal oscillation mode, are disposed on the surface of the diaphragm. When the piezoactuator is driven with a drive signal, the phase difference of a first detection signal output from the first electrode and a second detection signal output from the second electrode is detected. The frequency at which the detected phase difference becomes the maximum phase difference is then obtained, and a drive signal of a matching frequency is applied to the piezoelectric elements.
A drive circuit for a piezoactuator of which a major component is a diaphragm that is a diaphragm made from piezoelectric elements and oscillates when an ac signal is applied in a first oscillation mode and a second oscillation mode having a different oscillation direction, characterized by comprising:
In a control method for a drive circuit having a driver for applying a drive voltage signal that is an ac signal to a diaphragm of a piezoactuator, a voltage-controlled oscillator for outputting a drive voltage signal of a frequency corresponding to a frequency control voltage to the driver, and a phase difference detection circuit for receiving an electrical signal from the diaphragm representing oscillation in a first oscillation mode and an electrical signal representing oscillation in a second oscillation mode with an oscillation direction different from the first oscillation mode, and detecting a phase difference of these electrical signals, a piezoactuator drive circuit control method characterized by comprising:
In a control program for a drive circuit having a driver for applying a drive voltage signal that is an ac signal to a diaphragm of a piezoactuator, a voltage-controlled oscillator for outputting a drive voltage signal of a frequency corresponding to a frequency control voltage to the driver, a phase difference detection circuit for receiving an electrical signal from the diaphragm representing oscillation in a first oscillation mode and an electrical signal representing oscillation in a second oscillation mode with an oscillation direction different from the first oscillation mode, and detecting a phase difference of these electrical signals, and a processor, a control program running on said processor:
In a storage medium storing a control program for a drive circuit having a driver for applying a drive voltage signal that is an ac signal to a diaphragm of a piezoactuator, a voltage-controlled oscillator for outputting a drive voltage signal of a frequency corresponding to a frequency control voltage to the driver, a phase difference detection circuit for receiving an electrical signal from the diaphragm representing oscillation in a first oscillation mode and an electrical signal representing oscillation in a second oscillation mode with an oscillation direction different from the first oscillation mode, and detecting a phase difference of these electrical signals, and a processor, a computer-readable storage medium for storing a control program running on the processor a frequency control step for optimizing the oscillation frequency of the voltage-controlled oscillator based on the phase difference detected by the phase difference detection circuit.
A piezoactuator characterized by comprising:
Dependencies are inferred from the claim text.