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:
Sep. 19, 2000
Filed:
Feb. 26, 1998
Mitsuya Okada, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A tracking groove comprising a land area and a groove area is previously provided on a substrate of an optical disk, and a prepit is previously provided on a boundary line between the land area and the groove area of the tracking groove. When information is recorded on both the land and groove areas, a half-split photodetector split into two parts by a splitting line perpendicular to the radial direction of the optical disk is used as a photoreceiver for receiving light reflected from the optical disk. The photoreceivers are switched so that light reflected from the prepit is reproduced as a signal in any one of the two photodetectors. This enables reproduction signals derived from light reflected from the prepit to be reproduced at a good S/N ratio, thus realizing an optical information recording apparatus which bas a simple construction and enables information to be recorded on both the land and groove areas.