US Patent 7485357 Optical recording medium

An optical recording medium including: a substrate having translucency; a first protective layer thereon; a recording layer composed of a phase-change material; a second protective layer; and a reflective layer, wherein laser beam irradiation causes phase-change of the recording layer between a crystalline phase and an amorphous phase thereby at least one of to rewrite and to record information, wherein the phase-change material comprises Ga, Sb and Sn, Ga content, Sb content, and Sn content satisfy the following formula, and the total content of Ga, Sb and Sn is at least 80 atomic % of the entire phase-change material:GaαSbβSnγ(where, α+β+γ=100 atomic %),where 20≦−2.75α+0.708β+1.18γ−7.56≦43,and α/(α+β)≦0.12.