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. 18, 1990
Filed:
Mar. 18, 1988
Hideki Ohkawa, Tokyo, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
An information storage medium comprises a substrate, and a magnetic optical recording layer provided on the substrate. A surface portion of the recording layer has a hydrogen-doped portion having a higher hydrogen concentration than that of the other portions of the recording layer. Thus, the recording layer has two portions which have different coercive forces, though being of the same composition. The recording layer is immersed in an aqueous solution having a pH of 4 to 10, to cause hydrogenation reactions to take place on the surface of the recording layer. Another information storage medium comprises a substrate, a magneto-optical recording layer deposited on the substrate, containing a rare earth-transition metal amorphous alloy, and a protective layer deposited on the recording layer. A hydrogenated area is formed by doping hydrogen atoms in the surface portion of the recording layer before the protective layer is formed.