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:
Apr. 11, 2000
Filed:
Oct. 13, 1998
Hiroshi Nakayama, Miyagi, JP;
Etsuro Ikeda, Miyagi, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical disc in which a desired exchange reciprocal action is displayed between two sorts of the rare earth-transition metal alloy films to realize optimum recording/reproducing characteristics, and a manufacturing method for the optical disc. To this end, an optical disc 1 includes a first rare earth-transition metal alloy film containing rare earth elements and transition elements and a second rare earth-transition metal alloy film layered on the first rare earth-transition metal alloy film. The second rare earth-transition metal alloy film has a composition different from that of the first rare earth-transition metal alloy film and contains rare earth elements and transition elements. An oxidized area defined between the first rare earth-transition metal alloy film and the second rare earth-transition metal alloy film has an oxygen content not higher than 2.5 atom % and a thickness not larger than 7 nm.