Abstract: The phase-change optical recording medium having a substrate, and at least a first protective layer, a recording layer composed of a phase-change material, a second protective layer and a reflective layer disposed on the substrate in this sequence has a maximum recording linear velocity VH of 20 m/s to 60 m/s, a range of linear velocity recordable even when the recording linear velocity is continuously changed of 0.3VH to 1.0VH, and no occurrence of crystals causing a reproduction error in recorded marks.

Abstract: An optical disc having a transition linear velocity of 8-11 m/s when irradiating continuous light with 11±1 mW and a wavelength of 660±10 nm using a pickup head with a numerical aperture (NA) of 0.65, and satisfying the following condition: ?R=|Rb—Ra|?3% where Rb is a reflectance of an unrecorded area, and Ra is a reflectance of the top of an eye pattern after ten cycles of recording. In one recording mode therefor, the disc is rotated at a constant angular velocity so as to have a linear velocity of 3–4 m/s on an innermost track and a linear velocity of 8–9 m/s on an outermost track. In another mode, the disc is rotated at a constant angular velocity so as to have a linear velocity of 5–6 m/s on an innermost track and a linear velocity of 13–14 m/s on an outermost track.

Abstract: An optical recording medium including a substrate on which a first protective layer, an interface layer, a phase change recording layer, a second protective layer, an optional third protective layer (anti-sulfuration layer), and a reflective layer are accumulated in this order. The first protective layer contains a mixture of ZnS and SiO2 The interface layer contains a material containing Si and O. The phase change recording layer contains Sn, Sb, Ga, and Ge. In addition, the content of Si and O in the interface layer is 10 to 60% greater than a content of Si and O in the first protective layer.

Abstract: It is an object of the present invention to provide a phase-change information recording medium, and the like, which is easy to perform initial crystallization, exhibits good recording sensitivity at a linear velocity as high as 10 double speeds or more with as much capacity as DVD-ROM, is capable of overwrite recording and has good storage reliability. For this purpose, the phase-change information recording medium comprises a substrate and at least a first protective layer, a phase-change recording layer, a second protective layer, and a reflective layer disposed on the substrate in one of this sequence and reverse sequence wherein the phase-change recording layer comprises a composition expressed by Sn?Sb?Ga?Ge?Te?X? (In this regard, X represents at lease one element selected from Ag, Zn, In and Cu. ?, ?, ?, ?, ? and ? represent composition ratio (atomic percent) of each element and are expressed as 5???25, 40???91, 2???20, 2???20, 0???10, 0???10 and ?+?+?+?+?+?=100).

Abstract: A phase change optical recording medium having a wide recording power margin and excellent durability to repetitive recording is disclosed. The medium includes a first protective layer, a recording layer, an interface layer, a second protective layer, and a reflective layer, the layers disposed on a transparent substrate, wherein the interface layer includes a mixture of ZrO2. Preferably, the medium further includes a second interface layer including the mixture of ZrO2 between the first protective layer and the recording layer. In another preferable aspect, the mixture of ZrO2 is represented by the following formula: [(ZrO2)100-?(X)?]?(Z)?(ZnS)? wherein “X” represents an oxide selected from MgO, CaO, Sc2O3, Y2O3, and CeO2; “Z” represents an oxide selected from TiO2, SiO2, Al2O3, MgO, Ta2O5, and ZnO; “?” is 2-15 mol %; “?” is 40-100 mol %; “?” is 0-60 mol %; “?” is 0-60 mol %; and ?+?+?=100 mol %.

Abstract: An initialization method in which a phase change optical recording medium is initialized with a laser beam having a power density of from 15 to 22 mW/&mgr;M2 at a linear velocity of from 8 to 12 m/s. The phase change optical recording medium is formed of a transparent substrate having a guide groove on the surface thereof, a first protective layer, a recording layer, a second protective layer and a reflective layer. The recording layer material may be represented by the following composition formula: Ag&agr;X&bgr;Sb&dgr;Te&egr;Ge&ggr;, wherein X is at least one of Ga, In, Tl, Pb, Sn, Bi, Cd, Hg, Mn, Dy, Cu and Au, and &agr;, &bgr;, &dgr;, &egr;, and &ggr; have units of atomic % and satisfy particular relationships.

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: An optical recording method of recording information to a phase change optical recording medium with alternate application of peak power and bias power in a pulse manner and with changing a pulse application interval continuously from an inner part through an outer part of the recording medium with an interval proportional to a window width Tw and a fixed interval, comprising the step of starting a top peak power application interval with a delay from a data input pulse signal starting time for a target mark length nTw, where n denotes an integer in a range between 3 and 14, with changing the delay in proportion to the window width Tw with changing a proportionality factor discretely with respect each linear velocity.

Abstract: An optical disc having a transition linear velocity of 8-11 m/s when irradiating continuous light with 11±1 mW and a wavelength of 660±10 nm using a pickup head with a numerical aperture (NA) of 0.

Abstract: The present invention provides a recording method for a phase-change optical recording medium. The recording method of the present invention contains the step of irradiating an electromagnetic wave having a multipulse pattern so as to perform recording on a phase-change optical recording medium containing a phase-change recording layer. This method is characterised in that a starting time of a front pulse of the multipulse pattern delays 0.5T to 1.25T from a starting point of the first reference clock relative to the recording mark, where T is a reference clock of the multipulse pattern.

Abstract: A phase change optical recording medium having a wide recording power margin and excellent durability to repetitive recording is disclosed. The medium includes a first protective layer, a recording layer, an interface layer, a second protective layer, and a reflective layer, the layers disposed on a transparent substrate, wherein the interface layer includes a mixture of ZrO2. Preferably, the medium further includes a second interface layer including the mixture of ZrO2 between the first protective layer and the recording layer.

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).