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:
Dec. 02, 2008
Filed:
Feb. 13, 2007
Yasuharu Hashimoto, Minami-Minowa, JP;
Yasuharu Hashimoto, Minami-Minowa, JP;
Seiko Epson Corporation, , JP;
Abstract
A piezoelectric actuator includes: a ring-shaped piezoelectric element, vibration of the piezoelectric element being transmitted to an object; a first vibration area and a second vibration area provided on both sides of a bisector bisecting the piezoelectric element along a diameter of the piezoelectric element, the first vibration area and the second vibration area being respectively provided with at least one drive electrode to which a drive signal is supplied, the drive electrode being arranged substantially axisymmetrically with respect to the bisector, the drive signal including a phase-advance drive signal and a phase-delay drive signal having a predetermined drive phase difference, the phase-advance drive signal that is phase-advanced relative to the phase-delay drive signal being supplied to one of the first vibration area and the second vibration area and the phase-delay drive signal that is phase-delayed relative to the phase-advance drive signal being supplied to the other of the first vibration area and the second vibration area; and a detection electrode that detects vibrating condition of the piezoelectric element to output a vibration signal, the detection electrode being provided on at least one of the first vibration area and the second vibration area to which the phase-delay drive signal is supplied, the drive of the piezoelectric actuator being controlled based on a detected phase difference between one of the phase-advance drive signal and the phase-delay drive signal and the vibration signal.