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. 22, 2002
Filed:
Jun. 28, 2001
Asmo Co., Ltd., Shizuoka, JP;
Abstract
A stator includes a longitudinal-vibration sensing electrode. The stator also includes a torsional-vibration sensing piezoelectric element and a torsional-vibration sensing electrode plate for sensing torsional vibrations. A voltage signal from the torsional-vibration sensing electrode plate or a voltage signal from the longitudinal-vibration sensing electrode is sensed. Then, a drive voltage signal for driving the stator is generated in a self-excited oscillation drive circuit in such a manner that an actual vibrational frequency of the stator substantially coincides with a resonance frequency. Thereafter, the generated drive voltage signal is applied between a drive electrode and each one of first and second electrode plates.