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:
Jan. 05, 1999
Filed:
Sep. 26, 1997
Toshihisa Tanaka, Yokohama, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A compact magnetic field applying device rotates and holds a magnetic field generating member using a small-scale, light-weight vibration actuator. A permanent magnet applies a bias magnetic field on a magnetized information recording area of a magnetooptical disk, and is driven by a vibration actuator. When voltage is applied to a piezoelectric element of the vibration actuator, an annular elastic member generates a travelling wave due to a bending vibration in the perimeter direction of a groove on the elastic member. Because the elastic member and a moving member provided on the permanent magnet are pressed into contact by a coil spring, the permanent magnet rotates. When voltage is not applied to the piezoelectric element, because the elastic member and the moving member are pressed into contact, the permanent magnet is held in a specified rotational position.