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:
Feb. 18, 2003
Filed:
Aug. 11, 2000
Hiroshi Tomohiro, Shiga-ken, JP;
Naoki Fujii, Omihachiman, JP;
Murata Manufacturing Co., Ltd., Kyoto, JP;
Abstract
A DC voltage is applied to a piezoelectric body for polarization treatment in the air and in an atmosphere with a temperature equal to or higher than an aging temperature, and then, the piezoelectric body is aged at the aging temperature. The polarization degree is determined based on the frequency characteristic while the piezoelectric body is polarized. The application of the DC voltage is stopped at the time when the measured polarization degree reaches a set level. The set level is determined based on a correlation between the polarization degree obtained immediately before the application of the DC voltage is stopped and the stable polarization degree obtained after the aging and the ordinary temperature restoration following the stop of the voltage application.