Patent ID: 7364781

Claim:
An optical recording medium comprising a recording layer which comprises a phase-change recording material which is capable of performing a reversible phase change from a crystalline phase to an amorphous phase and vice versa by light irradiation of said phase-change recording material, said recording layer being capable of writing information therein, reading written information therefrom, and rewriting written information by utilizing said reversible phase change of said phase-change recording material, wherein when a recording mark formed in said recording layer is repeatedly read 5000 times, using a continuous wave laser beam having such an intensity Pr that satisfies the condition of 1.1≦R≦2.0, in which R is the ratio of a 5000 th repeated reading jitter σ repeat of a recording mark to a 1 st reading jitter σ 1 of said recording mark, namely R is σ repeat /σ 1 , and a jitter increasing ratio of said 5000 th repeated reading jitter σ repeat to said 1 st reading jitter σ 1 is d (=σ repeat /σ 1 ), said optical recording medium satisfies a relationship of d 1 >d ow , in which d 1 is said jitter increasing ratio of an initial writing mark, and d ow is a jitter increasing ratio of a 1000-times rewritten recording mark, wherein said phase-change recording material comprises a pseudo binary composition which has an X-ray diffraction spectrum such that a first peak is observed at a Bragg (2θ) angle of 27° to 29° and a second peak is observed at a Bragg (2θ) angle of 40° to 43° when a CuKα line having a wavelength of 1.54Å is used, wherein the second peak is wider than the first peak, wherein said pseudo binary composition is represented by Sb-TeM, comprising two portions, one portion being represented by Sb, and the other portion being represented by TeM, in which M represents a metal compound comprising at least Sb or Ge, provided that when TeM is Sb 2 Te 3 , said pseudo binary composition is a pseudo binary eutectic composition, and that at least one of the portions represented by TeM comprises Sb, and at least one of the other portions represented by TeM comprises Ge.