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:
Sep. 12, 2000
Filed:
Jan. 23, 1997
Masanori Kojima, Tokyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
An electromagnetic actuator drive circuit suppresses mechanical resonance which occurs in a magnetic head or an optical device whose position is controlled and giving a very small displacement to an electromagnetic actuator. By feeding back the terminal voltage E of the electromagnetic actuator to the signal current I.sub.s of the electromagnetic actuator through a feedback circuit, a Q factor in the case where short-circuit control is performed by voltage drive is realized so as to be about 0.5 which is the size of critical damping. The actuator drive circuit is applied for improving the picture quality reproduced by a video tape recorder, a projection image display, or the like and is capable of enhancing the ability to damp a moving object such as a magnetic head by performing short-circuit control by voltage drive.