Nikaido, Marmelstein, Murray & Oram
Optical recording medium
 An optical recording medium includes at least a substrate and a recording layer formed on the substrate, said recording layer being irradiated with an energy beam to change the optical properties thereof by directly or indirectly generated heat, thereby recording information, wherein said recording layer comprises four elements of tellurium (Te), germanium (Ge), gallium (Ga) and bismuth (Bi) and has a composition represented by the following formula: EQU (Te.sub.x Ge.sub.1-x).sub.1-y (Ga.sub.z Bi.sub.1-z).sub.y wherein PA1 0.40.ltoreq.x.ltoreq.0.75 PA1 0.02.ltoreq.y.ltoreq.0.30 and PA1 0.05.ltoreq.z.ltoreq.0.50, PA1 x is the molar fraction of Te in Te-Ge, y is the molar fraction of the total amount of Bi and Ga in the recording layer, and z is the molar fraction of Ga in Ga-Bi. The optical recording medium of the present invention exhibits excellent CNR and recording sensitivity, no significant noise, a large amplitude of read-out signal, no significant jitter fluctuation excellent capability for high-speed and high-density recording, excellent life of media and resistance to moisture-and-heat, and high reliability. 
Toray Industries, Inc.
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Toshiharu Naoya Gentaro Osamu
Nakanishi Seo Ohbayashi Watanabe