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US 4,645,712 AGranted
Information recording medium
AssigneeHitachi, Ltd.
InventorsMasaji Ishigaki, Tetsu Ohishi, Nobuhiro Tokusyuku, Yoshie Kodera, Yukio Fukui
Life of this patent
Estimating the term…
Abstract
A information recording medium has characteristics of high sensitivity and high density. The medium has a double layer formed on a transparent substrate, the double layer comprising a highly transparent recording layer, for example, Sb.sub.2 Se.sub.3 layer and a highly reflective layer, for example, Bi layer. The highly transparent recording layer includes Bi so as to set a minimum value of a reflection factor in prerecording 8 to 16 percentages.
Claims7
An information recording medium comprising:
- a substrate suitable for formation of said recording medium, and
- a double layer formed on said substrate, said double layer including a highly transparent recording layer and a highly reflective layer, said highly transparent recording layer being a compound of Se and an element selected from the group consisting of Sb, In and Te admixed with a metal element having a highly optical absorption characteristic selected from the group consisting of Bi, Al, Ni, Cr, Co, Ti, Zr, Sn, Hf, Au, Ag, Zn, Pb, and Ta, so that a refractive index of said highly transparent recording layer is set so as to control a minimum value of a reflection factor of said double layer to a predetermined value.
Dependencies are inferred from the claim text.