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:
Feb. 01, 2000
Filed:
Aug. 21, 1997
Hidekazu Seto, Kanagawa, JP;
Kenji Nagashima, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
The present invention provides a disc drive apparatus which identifies a type of a disc mounted on the apparatus by using reflected beam data obtained from a laser beam focused on the disc surface and other reflected beam data obtained from the laser beam being focused on the disc signal plane. For example, while forcibly changing the laser beam focusing point within a variable range at a predetermined velocity, a luminous energy signal or a focus error signal is used to count a time difference between a timing of focusing on the disc surface and a timing of focusing on the disc signal plane. According to the time difference obtained, the disc mounted is identified as a first type of disc or a second type of disc.