Phase change type optical recording medium

摘要

A phase change type optical recording medium comprises:
a substrate;
a crystallized phase change recording layer disposed above the substrate, to receive a pulse-shaped light beam when forming recording marks by a mark length modulation; and
a reflection layer disposed above the phase change recording layer,
wherein said phase change recording layer is made of a material having a composition ratio near an eutectic composition of Sb and Ga, and receives a light beam formed by a single recording pulse when forming a recording mark having a size less than or equal to a predetermined size N , and receives a light beam formed by a plurality of recording pulses when forming a recording mark having a size greater than the pre-determined size N , said predetermined size N being set with reference to a reference size which is sum of a beam spot diameter of the light beam and a distance traveled by the light beam within a time amounting to a sum of rising and falling time constants of a light beam power.