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:
Jan. 25, 2000
Filed:
Apr. 08, 1998
Applicant:
Inventors:
Assignee:
Ricoh Company, Ltd., Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
3692751 ; 369 13 ; 3692754 ; 428 643 ;
Abstract
An erasable phase change recording medium includes a transparent substrate, a recording layer of a phase change material provided on the substrate, and a protection layer provided to protect the recording layer on the substrate. Tracks are formed with alternate grooves and lands on the substrate of the recording medium and data is recorded to at least one of the grooves and the lands. The recording medium is configured to have a track pitch between 0.6 .mu.m and 0.8 .mu.m and a groove depth between 0.11.L and 0.18.L where L is a wavelength of a laser beam.