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:
May. 11, 2009
Filed:
Oct. 31, 2006
Hidehiro Akahane, Suwa, JP;
Akihiro Sawada, Suwa, JP;
Makoto Furuhata, Suwa, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
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.