The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 10, 2006
Filed:
Mar. 30, 2004
Jun Matsuzaki, Shiojiri, JP;
Takashi Kawaguchi, Shiojiri, JP;
Makoto Okeya, Shiojiri, JP;
Seiko Epson Corporation, Tokyo, JP;
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 ()) for detecting detection signals of longitudinal oscillation and bending oscillation from an oscillator () and detecting the phase difference between these two signals, frequency control devices (to) 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 () on the basis of the results of this comparison, and an amplitude detection device (amplitude detection circuit ()) for detecting the amplitude of the detection signal of the piezoelectric element (). 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.