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:
Feb. 17, 2004
Filed:
Dec. 20, 2001
Makoto Matsukawa, Yamanashi-ken, JP;
Seiro Oshima, Yamanashi-ken, JP;
Toshihiko Takishita, Yamanashi-ken, JP;
Pioneer Corporation, Tokyo, JP;
Abstract
An optical recording medium is provided which comprises: a substrate including concentrically or spirally formed grooves each having a V-shaped cross section; a first dielectric layer formed on the substrate; a phase-change recording layer formed on the first dielectric layer; a second dielectric layer formed on the phase-change recording layer; and a metallic reflecting layer formed on the second dielectric layer. In particular, the optical recording medium is so formed that an objective lens having an aperture number of 0.55-0.70 can be used and a laser beam having a wavelength of 600-700 nm and passing through the objective lens is passed through the substrate and then converged on the recording layer, thereby recording or reproducing information on the recording layer in areas corresponding to the grooves. Specifically, the optical recording medium further comprises a third dielectric layer consisting of a nitride, the third dielectric layer being disposed between the first dielectric layer and the phase-change recording layer. In this way, it is possible to prevent a deterioration possibly caused due to a heat in the boundary between the first dielectric layer and the second dielectric layer, thereby greatly increasing the number of possible times for over-write recording.