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. 14, 1995
Filed:
Aug. 04, 1994
Yutaka Murakami, Katano, JP;
Toru Nakamura, Katano, JP;
Takao Hayashi, Katano, JP;
Akira Matsubara, Kameoka, JP;
Hisashi Aizawa, Nara, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A lens drive mechanism for an optical disc player includes a movable unit including an objective lens for focusing a coherent beam of light on an optical disc, a lens holder carrying the objective lens, focusing and tracking coils secured to opposite portions of a periphery of the lens holder. The lens drive mechanism also includes permanent magnets and yokes, and a plurality of support members connected at one end to the periphery of the lens holder and at the opposite end to a support fixture for supporting the movable unit for movement in focusing and tracking directions substantially perpendicular to each other. A upper set of the support members has a spring constant different from that of a lower set of the support members, and the product of the spring constant of the upper set of the support members multiplied by a distance from the center of gravity of the movable unit to a position of securement of the upper set of the support members is chosen to be equal to the product of the spring constant of the lower set of the support members multiplied by a distance from the center of gravity of the movable unit to a position of securement of the lower set of the support members.