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. 01, 1998
Filed:
Mar. 17, 1997
Tadao Yoshida, Kanagawa, JP;
Chiaki Nonaka, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
Edges on both sides of each groove on a disk 11 are wobbled to indicate the addresses of recording locations. A laser beam for detection of data is radiated to a land for recording data, forming a spot 51-1. Two laser beams for detection of a tracking error are radiated to edges on both sides of a groove in such a way that the middle between the two laser beams coincides with the center of the groove, forming spots 51-2 and 51-3. By using such a tracking-error detecting laser beam to read out address information, the laser beam can be radiated to only the edge on a predetermined side of a groove. As a result, an address can be read out with a reduced amount of crosstalk from another groove even if the track pitch is small. Address information is thus read out with a highly accurate degree even in the case of a small track pitch.