Optical recording medium, recording material, method of producing optical recording medium, and optical recording, reading and rewriting method

A method of producing 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 5000th repeated reading jitter σrepeat of a recording mark to a 1st reading jitter σ1 of said recording mark, namely R is σrepeat/σ1, and a jitter increasing ratio of said 5000th repeated reading jitter σrepeat to said 1st reading jitter σ1 is d (=σrepeat/σ1), said optical recording medium satisfies a relationship of d1>dow, in which d1 is said jitter increasing ratio of an initial writing mark, and dow is a jitter increasing ratio of a 1000-times rewritten recording mark, comprising the step of forming said recording layer by performing sputtering, using a target, with a sputtering power of 0.1 kW to 1.5 kW, said target being prepared by fusing and mixing a composition composed of a plurality of elements with a predetermined composition, crushing said composition to prepare a pulverized composition, and sintering said pulverized composition.

A method of producing 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 5000th repeated reading jitter σrepeat of a recording mark to a 1st reading jitter σ1 of said recording mark, namely R is σrepeat/σ1, and a jitter increasing ratio of said 5000th repeated reading jitter σrepeat to said 1st reading jitter σ1 is d (=σrepeat/σ1), said optical recording medium satisfies a relationship of d1>dow in which d1 is said jitter increasing ratio of an initial writing mark, and dow is a jitter increasing ratio of a 1000-times rewritten recording mark, comprising the step of forming said recording layer by sputtering, using a target, with a sputtering pressure of 0.8 mTorr to 9 mTorr, said target being prepared by fusing and mixing a composition composed of elements with a predetermined composition, crushing said composition to prepare a pulverized composition, and sintering said pulverized composition.

A method of producing 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 5000th repeated reading jitter σrepeat of a recording mark to a 1st reading jitter σ1 of said recording mark, namely R is σrepeat/σ1, and a jitter increasing ratio of said 5000th repeated reading jitters repeat to said 1st reading jitter σ1 is d (=σrepeat/σ1), said optical recording medium satisfies a relationship of d1>dow, in which d1 is said jitter increasing ratio of an initial writing mark, and dow is a jitter increasing ratio of a 1000-times rewritten recording mark, comprising the step of forming said recording layer by performing sputtering, using a target, in a sputtering chamber with the pressure in said sputtering chamber being set at a vacuum degree of 9×10−7 Torr or less immediately before said recording layer is formed, said target being prepared by fusing and mixing a composition composed of a plurality of elements with a predetermined composition, crushing said composition to prepare a pulverized composition, and sintering said pulverized composition.

A method of writing information, reading written information, and rewriting written information in an optical recording medium with irradiating said optical recording medium with a laser beam with a spot diameter of 0.05 μm to 2.0 μm, said optical information 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 5000th repeated reading jitter σrepeat of a recording mark to a 1st reading jitter σ1 of said recording mark, namely R is σrepeat/σ1, and a jitter increasing ratio of said 5000th repeated reading jitter σrepeat to said 1st reading jitter σ1 is d (=σrepeat/σ1), said optical recording medium satisfies a relationship of d1>dow, in which d1 is said jitter increasing ratio of an initial writing mark, and dow is a jitter increasing ratio of a 1000-times rewritten recording mark.

A method of writing information, reading written information, and rewriting written information in an optical recording medium with irradiating said optical recording medium with a linear recording speed of 1.2 m/s to 25 m/s, said optical information 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 5000th repeated reading jitter σrepeat of a recording mark to a 1st reading jitter σ1 of said recording mark, namely R is σrepeat/σ1, and a jitter increasing ratio of said 5000th repeated reading jitter σrepeat to said 1st reading jitter σ1 is d (=σrepeat/σ1), said optical recording medium satisfies a relationship of d1>dow, in which d1 is said jitter increasing ratio of an initial writing mark, and dow is a jitter increasing ratio of a 1000-times rewritten recording mark.