Patent ID: 7858167

Claim:
A rewritable optical recording medium comprising: a substrate having a guide groove formed thereon; a phase-change type recording layer, a portion in a crystalline state of the phase-change type recording layer corresponds to an unrecorded or erased state, and a portion in an amorphous state of the phase-change type recording layer corresponds to a recorded state, so that an amorphous mark corresponding to the recorded state is formed upon irradiation with a recording laser beam; the phase-change type recording layer contains an alloy having, as a main component, a composition represented by Ge y (Sb x Te 1−x ) 1−y (where 0.01<y<0.06 and 0.85<x<0.9), wherein Ge ranges from 1 atomic % to 30 atomic %, and Te ranges from 10 atomic % to 30 atomic %; and the phase-change type recording layer contains at least 10 atomic % of Te, Sb/Te is at least 4.5, and the atomic ratio of Ge to Te is from 1:3 to 1:20.