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:
Nov. 16, 1999
Filed:
Mar. 17, 1998
Tomoo Sukagawa, Higashine, JP;
Keiji Aruga, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A magnetic circuit for a voice coil motor of flat-coil type used with a magnetic device is disclosed. The magnetic circuit is intended to flatten the torque constant curve for swinging the rotor of the voice coil motor while at the same time preventing the torque constant from decreasing. For this purpose, the magnetic circuit comprises an upper yoke and a lower yoke opposed to a flat coil arranged on the rotor, a pair of side yokes for coupling the upper and lower yokes to each other at the ends thereof, and a magnet arranged on the lower yoke. The magnet is shaped arcuate so that the width in the neighborhood of each end thereof in the direction of motion of the flat coil is larger than a standard width and smaller than the standard width in the portions of the magnet between each end and the central portion thereof.