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:
Aug. 20, 2002
Filed:
Nov. 07, 2000
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
An optical recording medium capable of obtaining a large reproduced signal from the recoded mark, a large reproduced signal of a pre-pit and a large tracking signal both in an area of the grooves and an area of the pre-pits, which provides a sufficient time allowance for switching tracking to that suitable for the area of the grooves or to that suitable for the area of the pre-pits. An optical recording medium comprising a substrate whereon tracks each comprising at least of writable grooves and pre-pits deeper than or equal to the grooves are formed and areas of a relatively shallow pits are each provided between an area of the deep pits and an area of the grooves. The depth Dg of the grooves, the depth Dsp of the shallow pits and the depth Ddp of the deep pits satisfy the following conditions: Dg<&lgr;/(8n), &lgr;/(8n)<Ddp<&lgr;/(4n) and Dg≦Dsp<Ddp. Tracking method is switched over in the shallow pit area when recording or reproducing information on the optical recoding medium.