Abstract: Optical information recording is achieved at high speed such as sixthfold to eightfold speed of DVD while suppressing jitter by a high-speed recording strategy such as a 2T period strategy, by once reducing the optical power of the optical beam used for optical recording, when starting recording of an amorphous mark pattern after the step of forming a crystalline space region but before the step of irradiating the optical beam with a peak power level for the mark formation, such that the optical power of the optical beam is reduced below the erasing optical power used for forming the crystalline space region.

Abstract: An optical recording medium has a phase-change recording layer containing Sb and Te as essential elements therefor, to which is added at least one element selected from the group consisting of Ag, Au, Cu, Zn, B, Al, Ga, In, Si, Ge, Sn, Pb, N, P, Bi, La, Ce, Gd, and Tb, the recording layer being capable of assuming an amorphous phase changed from a crystalline phase by the application of a laser beam thereto, thereby optically recording information. Recording marks are formed in the recording medium by converting a light emission wave of laser beam into a recording pulse train comprising a plurality of on-pulses and off-pulses, with a recording frequency being continuously changed corresponding to the location of each of the recording marks in the radial direction of said recording medium. A recording apparatus has laser beam driving circuit means, signal generation means, and signal transmission means for achieving the above recording method.

Abstract: An optical recording medium including a recording layer which includes a reversible phase-change recording material, the recording layer being capable of writing information therein, reading written information therefrom, and rewriting written information by utilizing the reversible phase change of the phase-change recording material, wherein when a recording mark formed in the 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 ?repeat/?1 as defined in the specification, the optical recording medium satisfies a relationship of d1>dow as defined in the specification. The phase-change recording material, a method of producing the optical recording medium, and a method of writing information in the optical recording medium, reading written information therefrom and rewriting written information therein are proposed.

Abstract: An optical recording medium including a recording layer which includes a reversible phase-change recording material, the recording layer being capable of writing information therein, reading written information therefrom, and rewriting written information by utilizing the reversible phase change of the phase-change recording material, wherein when a recording mark formed in the 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 ?repeat/?1 as defined in the specification, the optical recording medium satisfies a relationship of d1>dow as defined in the specification. The phase-change recording material, a method of producing the optical recording medium, and a method of writing information in the optical recording medium, reading written information therefrom and rewriting written information therein are proposed.

Abstract: A phase-change optical recording medium capable of implementing record and readout operations of information data through reversible phase transition between amorphous and crystalline states induced by light beam irradiation in a recording layer included in the recording medium, including at least a transparent substrate and contiguous layers formed on the substrate in order as follows, a lower dielectric protective layer, the recording layer, an upper dielectric protective layer, and a reflective/heat dissipating layer, in which the upper dielectric protective layer essentially consists of a mixture of ZrO2 and SiO2, having a composition of (ZrO2)100-x (SiO2)x, where 0<x<60 (mole %).

Abstract: An optical recording medium has a phase-change recording layer containing Sb and Te as essential elements therefor, to which is added at least one element selected from the group consisting of Ag, Au, Cu, Zn, B, Al, Ga, In, Si, Ge, Sn, Pb, N, P, Bi, La, Ce, Gd, and Tb, the recording layer being capable of assuming an amorphous phase changed from a crystalline phase by the application of a laser beam thereto, thereby optically recording information. Recording marks are formed in the recording medium by converting a light emission wave of laser beam into a recording pulse train comprising a plurality of on-pulses and off-pulses, with a recording frequency being continuously changed corresponding to the location of each of the recording marks in the radial direction of said recording medium. A recording apparatus has laser beam driving circuit means, signal generation means, and signal transmission means for achieving the above recording method.

Abstract: A phase-change optical information recording medium capable of recording information therein, reproducing recorded information therefrom, rewriting recorded information, and erasing recorded information therefrom, which phase-change optical information recording medium is provided with a recording layer containing therein a phase-change recording material including Ge, Ga, Sb, Te, and one element selected from the group consisting of Mg and Ca, which recording material is capable of performing a reversible phase transition from a noncrystalline phase to a crystalline phase and vice verse with the application of an electromagnetic wave thereto.

Abstract: An optical recording medium has a phase-change recording layer containing Sb and Te as essential elements therefor, to which is added at least one element selected from the group consisting of Ag, Au, Cu, Zn, B, Al, Ga, In, Si, Ge, Sn, Pb, N, P, Bi, La, Ce, Gd, and Tb, the recording layer being capable of assuming an amorphous phase changed from a crystalline phase by the application of a laser beam thereto, thereby optically recording information. Recording marks are formed in the recording medium by converting a light emission wave of laser beam into a recording pulse train comprising a plurality of on-pulses and off-pulses, with a recording frequency being continuously changed corresponding to the location of each of the recording marks in the radial direction of said recording medium. A recording apparatus has laser beam driving circuit means, signal generation means, and signal transmission means for achieving the above recording method.

Abstract: An optical recording medium comprising a recording layer which comprises a phase-change recording material causing a reversible phase change between a crystalline phase and an amorphous phase by irradiation with an electromagnetic wave, wherein the phase-change recording material mainly comprises materials expressed by the composition formula X&agr;Ge&bgr;Mn&ggr;Sb&dgr;Te&egr; with each of the components respectively fulfills 0≦&agr;≦5, 1≦&bgr;≦5, 1≦&ggr;≦10, 65 ≦&dgr;<80, 15≦&egr;≦25, and &agr;≦&ggr; (where X expresses at least one of Ga and Sn, &agr;, &bgr;, &ggr;, &dgr;, and &egr; expresses atomic percentage, and fulfills &agr;+&bgr;+&ggr;+&dgr;+&egr;=100).

Abstract: A recording method forms recording marks according to a mark length modulation by irradiating a pulse-shaped light beam with respect to a crystallized phase change recording layer of a phase change type optical recording medium which comprises at least the phase change recording layer and a reflection layer on a substrate. The recording method irradiates 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, where the predetermined size N is 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, and irradiates a light beam formed by a plurality of recording pulses when forming a recording mark having a size greater than the predetermined size N.

Abstract: A sputtering target contains a target material including as constituent elements Ag, In, Te and Sb with the respective atomic percents (atom. %) of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 0.5≦&agr;<8, 5 ≦&bgr;≦23, 17 ≦&ggr;≦38, 32≦&dgr;≦73, &agr;≦&bgr;, and &agr;+&bgr;+&ggr;+&dgr;=100, and a method of producing the above sputtering target is provided. An optical recording medium includes a recording layer containing a phase-change recording material which includes as constituent elements Ag, In, Te and Sb with the respective atomic percents of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 1≦&agr;<6, 7≦&bgr;≦20, 20≦&ggr;≦35, 35≦&dgr;≦70, and &agr;+&bgr;+&ggr;+&dgr;=100, and is capable of recording and erasing information by utilizing the phase change of the recording material in the recording layer.

Abstract: An optical recording medium which comprises a substrate and a recording layer disposed on the substrate, in which the recording layer comprises Ga and Sb, a content of the Sb is 80 atm % to 95 atm % relative to a total content of the Ga and the Sb in the recording layer, and recording and erasing are carried out by a reversible phase change between an amorphous phase and a crystalline phase in the recording layer.

Abstract: A sputtering target contains a target material including as constituent elements Ag, In, Te and Sb with the respective atomic percents (atom. %) of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 0.5≦&agr;<8, 5≦&bgr;≦23, 17≦&ggr;≦38, 32≦&dgr;≦73, &agr;≦&bgr;, and &agr;+&bgr;+&ggr;+&dgr;=100, and a method of producing the above sputtering target is provided. An optical recording medium includes a recording layer containing a phase-change recording material which includes as constituent elements Ag, In, Te and Sb with the respective atomic percents of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 1≦&agr;<6, 7≦&bgr;≦20, 20≦&ggr;≦35, 35≦&dgr;≦70, and &agr;+&bgr;+&ggr;+&dgr;=100, and is capable of recording and erasing information by utilizing the phase change of the recording material in the recording layer.

Abstract: An information recording method including irradiating a phase change recording layer of an optical recording medium with either a multi-pulse laser light train having a recording power of Pw or laser light having an erasing power Pe to record a mark having a length nT in the recording layer, wherein n is an integer of from 3 to 14 and T represents a clock cycle, wherein the multi-pulse laser light train has a constitution such that a heating pulse and a cooling pulse are alternated and the number of heating pulses and the number of cooling pulses each increases by 1 when n increases by 2, and wherein when n is from 6 to 14, the last heating pulse and last cooling pulse have a pulse width of from 0.5T to 0.9T and from 0.7T to 1.5T, respectively.

Abstract: An optical recording medium including a recording layer which includes a reversible phase-change recording material, the recording layer being capable of writing information therein, reading written information therefrom, and rewriting written information by utilizing the reversible phase change of the phase-change recording material, wherein when a recording mark formed in the 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 &sgr;repeat/&sgr;1 as defined in the specification, the optical recording medium satisfies a relationship of d1>dow as defined in the specification. The phase-change recording material, a method of producing the optical recording medium, and a method of writing information in the optical recording medium, reading written information therefrom and rewriting written information therein are proposed.

Abstract: An optical recording medium has a phase-change recording layer containing Sb and Te as essential elements therefor, to which is added at least one element selected from the group consisting of Ag, Au, Cu, Zn, B, Al, Ga, In, Si, Ge, Sn, Pb, N, P, Bi, La, Ce, Gd, and Tb, the recording layer being capable of assuming an amorphous phase changed from a crystalline phase by the application of a laser beam thereto, thereby optically recording information. Recording marks are formed in the recording medium by converting a light emission wave of laser beam into a recording pulse train comprising a plurality of on-pulses and off-pulses, with a recording frequency being continuously changed corresponding to the location of each of the recording marks in the radial direction of said recording medium. A recording apparatus has laser beam driving circuit means, signal generation means, and signal transmission means for achieving the above recording method.

Abstract: An optical recording medium has a phase-change recording layer containing Sb and Te as essential elements therefor, to which is added at least one element selected from the group consisting of Ag, Au, Cu, Zn, B, Al, Ga, In, Si, Ge, Sn, Pb, N, P, Bi, La, Ce, Cd, and Tb, the recording layer being capable of assuming an amorphous phase changed from a crystalline phase by the application of a laser beam thereto, thereby optically recording information. Recording marks are formed in the recording medium by converting a light emission wave of laser beam into a recording pulse train comprising a plurality of on-pulses and off-pulses, with a recording frequency being continuously changed corresponding to the location of each of the recording marks in the radial direction of said recording medium. A recording apparatus has laser beam driving circuit means, signal generation means, and signal transmission means for achieving the above recording method.

Abstract: An optical recording medium has a phase-change recording layer containing Sb and Te as essential elements therefor, to which is added at least one element selected from the group consisting of Ag, Au, Cu, Zn, B, Al, Ga, In, Si, Ge, Sn, Pb, N, P, Bi, La, Ce, Gd, and Tb, the recording layer being capable of assuming an amorphous phase changed from a crystalline phase by the application of a laser beam thereto, thereby optically recording information. Recording marks are formed in the recording medium by converting a light emission wave of laser beam into a recording pulse train comprising a plurality of on-pulses and off-pulses, with a recording frequency being continuously changed corresponding to the location of each of the recording marks in the radial direction of said recording medium. A recording apparatus has laser beam driving circuit means, signal generation means, and signal transmission means for achieving the above recording method.

Abstract: An optical recording medium comprising a recording layer which comprises a phase-change recording material causing a reversible phase change between a crystalline phase and an amorphous phase by irradiation with an electromagnetic wave, wherein the phase-change recording material mainly comprises materials expressed by the composition formula X&agr;Ge&bgr;Mn&ggr;Sb&dgr;Te&egr; with each of the components respectively fulfills 0≦&agr;≦5, 1≦&bgr;≦5, 1≦&ggr;≦10, 65 ≦&dgr;80, 15≦&egr;≦25, and &agr;≦&ggr; (where X expresses at least one of Ga and Sn, &agr;, &bgr;, &ggr;, &dgr;, and &egr; expresses atomic percentage, and fulfills &agr;+&bgr;+&ggr;+&dgr;+&egr;=100).

Abstract: A sputtering target for fabricating a recording layer of a phase-change type optical recording medium contains a compound or mixture including as constituent. elements Ag, In, Te and Ob with the respective atomic percent (atom. %) of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 2≦&agr;≦30, 3≦&bgr;≦30, 10≦&ggr;≦50, 15≦&dgr;≦83 and &agr;+&bgr;+&ggr;+&dgr;=100, and a method of producing the above sputtering target is provided. A phase-change type optical recording medium includes a recording layer containing as constituent elements Ag, In, To and Sb with the respective atomic percent of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 0<&agr;≦30, 0<&bgr;≦30, 10≦&ggr;≦50, 10≦&dgr;≦80, and &agr;+&bgr;+&ggr;+&dgr;=100, and is capable of recording and erasing information by utilizing the phase changes of a recording material in the recording layer.