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:
Jun. 06, 2000
Filed:
Sep. 30, 1998
Jiro Yoshinari, Nagano, JP;
Masanori Kosuda, Nagano, JP;
Hiroshi Shingai, Nagano, JP;
Hiroshi Chihara, Nagano, JP;
TDK Corporation, Tokyo, JP;
Abstract
An optical recording medium of phase change type which exhibits an increased number of overwritable operations is provided. The optical recording medium comprises a substrate, and a first dielectric layer, a recording layer, a second dielectric layer, and a metal reflective layer disposed on the substrate in this order, and the first dielectric layer comprises a dielectric layer 1a on the side of the substrate and a dielectric layer 1b in contact with the recording layer. The dielectric layer 1a comprises ZnS--SiO.sub.2, and the dielectric layer 1b comprises Si.sub.3 N.sub.4 and/or Ge.sub.3 N.sub.4. The second dielectric layer may comprise a single layer of ZnS--SiO.sub.2, SiO.sub.2 or oxide of a rare earth metal. The second dielectric layer may also comprise a laminate of a dielectric layer 2a comprising ZnS--SiO.sub.2 on the side of the substrate and a dielectric layer 2b comprising SiO.sub.2 or oxide of a rare earth metal on the side of the reflective layer. The dielectric layer 1b has a thickness of 0.5 to 40 nm, and ratio of thickness of the dielectric layer 1b to the thickness of the first dielectric layer is up to 0.5.