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:
Apr. 07, 2009
Filed:
Jul. 07, 2005
Reiko Nagahama, Shiojiri, JP;
Yutaka Yamazaki, Suwa, JP;
Reiko Nagahama, Shiojiri, JP;
Yutaka Yamazaki, Suwa, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
A generally diamond-shaped detection electrode is formed in the approximate center of the piezoelectric element. The strain resulting from the bending secondary vibration mode in the vicinity of the detection electrode is minimized because the detection electrode is formed in such a manner as to include a vibrational node of the longitudinal primary vibrational mode and a vibrational node of the bending secondary vibrational mode. As a result, when the phase difference between the drive signal and the detection signal is detected, the effect of vibration in the bending secondary vibration mode on the detected phase difference can be suppressed and a single drive frequency can be determined with respect to a prescribed phase difference. Thus, the drive performance of the vibrating body with respect to a driven body (i.e., a body driven by the vibrating body) can be reliably improved because, by controlling the drive frequency such that the phase difference equals a prescribed value, the vibrating body can be made to vibrate at a desired frequency and vibrate in such a manner that the desired vibration components are achieved in each vibration mode.