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:
Oct. 19, 2004
Filed:
Oct. 11, 2002
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An objective lens ( ) for an optical disk, which focuses a light beam from a light source, is designed so that a third-order coma aberration generated when the objective lens is inclined at a unit angle is larger than a third-order coma aberration generated when the optical disk ( ) is inclined at the unit angle, mounted on an actuator for inclining the objective lens according to an inclination amount of the optical disk, and used. With this structure, it is possible to obtain an objective lens for an optical disk that has a large numerical aperture and is easy to manufacture and assemble, and in which the third-order coma aberration generated when the optical disk surface is inclined owing to a warp or the like can be corrected by small inclination of the objective lens, so as to reduce a residual astigmatism, which is generated according to the inclination amount, after the correction.