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:
Dec. 05, 2006
Filed:
Jul. 09, 2002
Toshikazu Kobayashi, Tokyo, JP;
Toshikazu Kobayashi, Tokyo, JP;
Sony Computer Entertainment Inc., Tokyo, JP;
Abstract
An objective lens of an optical pickup is made to move from far position to near position with respect to DVD with constant speed, and a timer counts time taken for the movement of a focus of a laser beam between recording layers of the DVD on the basis of a focus error signal obtained from this movement. In the case of the DVD of the single-layer, since the recording layer is one-layer, and there is no interlayer, count value becomes small value. While, in the case of DVD of the multi-layer, the recording layer consists of a plurality of layers, thus one or plural-interlayer exists, therefore, count value becomes large value. Accordingly, if small count value is obtained, its DVD is discriminated as DVD of the single-layer. While, if large count value is obtained, its DVD is discriminated as DVD of the multi-layer.