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. 27, 2007
Filed:
May. 05, 2004
Yoshiharu Kobayashi, Katano, JP;
Yasumori Hino, Ikoma, JP;
Yoshiharu Kobayashi, Katano, JP;
Yasumori Hino, Ikoma, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical disc drive includes an objective lens for focusing light on an optical disc with five or more stacked data storage layers and a tilt control mechanism for controlling a tilt angle defined between the optical axis of the light and a normal to the storage layers. The drive reads and/or writes data from/on a selected one of the storage layers by focusing the light on the selected layer. The numerical aperture NA of the objective lens is defined so as to fall within the range of 1.3009×D−2.9315×D+2.3133×D−0.0502 to 1.3009×D−2.9315×D+2.3133×D+0.2028, where D is a distance (mm) from a light incident side of the disc to the deepest one of the storage layers, which is located most distant from the light incident side.