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. 19, 2009
Filed:
Aug. 22, 2006
Osamu Urano, Okaya, JP;
Osamu Urano, Okaya, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
The piezoelectric actuator drive control device has a controller, and executes an initialization process including an optimum phase difference acquisition process Pand a phase difference inversion detection process Pat a predetermined frequency. As a result, the optimum phase difference is updated each time the optimum phase difference acquisition process Pruns to account for wear or temperature change from continuous operation. Furthermore, even if the phase difference between the drive signal and detection signal inverts during a drive frequency sweep due to variation in the vibration characteristic of the piezoelectric actuator, the phase difference inversion frequency and clamping frequency are reset each time the phase difference inversion detection process Pis executed, thus preventing phase difference feedback control errors. Appropriate drive control based on the optimum phase difference can therefore be provided because the suitability and stability of the optimum phase difference are assured.