Abstract: An optical recording medium including a transparent substrate; and at least one multi-layer information layer located on the transparent substrate and including a phase change recording layer configured to record information by changing its phase between a crystallization state and an amorphous state, a protective layer, and a reflection layer, wherein the average of partial response signal-to-noise ratio (PRSNR) in all data regions of the recording medium is not less than 15.0 after one direct overwriting (DOW1) cycle and the standard deviation of inter-track distribution of PRSNR is not greater than 0.3.

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: In an optical disk substrate film-formation apparatus which prepared an optical disk by forming a thin film on a substrate, the optical disk substrate is held by a holder section. A contact support surface is provided to the holder section which closely contacts at least a portion of the surface of the optical disk substrate rear to the surface where the think film is formed.

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: 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 0.5 T to 1.25 T 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: 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: The object is to provide an optical recording method improving the recording characteristics and uniformity in a CAV recording on a phase-change optical recording medium, particularly a high-speed rewritable DVD medium, and a phase-change optical recording medium and an optical recording apparatus used by the method.

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 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: A phase-change optical information recording medium in which information can be recorded, reproduced and rewritten and which includes a first transparent substrate having a wobbling guide groove which is spirally formed thereon at a pitch; a first dielectric layer located overlying the first transparent substrate and having an optical thickness of from 80 nm to 200 nm; a phase-change recording layer located overlying the first dielectric layer and having an optical thickness of from 20 to 50 nm when the recording layer is in an erased state; a second dielectric layer located overlying the recording layer and having an optical thickness of from 10 nm to 70 nm; a reflection layer located overlying the second dielectric layer; optionally a third dielectric layer located between the second dielectric layer and the reflection layer; and a second transparent substrate located overlying the reflection layer.

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: A phase-change optical information recording medium in which information can be recorded, reproduced and rewritten and which includes a first transparent substrate having a wobbling guide groove which is spirally formed thereon at a pitch; a first dielectric layer located overlying the first transparent substrate and having an optical thickness of from 80 nm to 200 nm; a phase-change recording layer located overlying the first dielectric layer and having an optical thickness of from 20 to 50 nm when the recording layer is in an erased state; a second dielectric layer located overlying the recording layer and having an optical thickness of from 10 nm to 70 nm; a reflection layer located overlying the second dielectric layer; optionally a third dielectric layer located between the second dielectric layer and the reflection layer; and a second transparent substrate located overlying the reflection layer.

Abstract: A phase-change optical information recording medium in which information can be recorded, reproduced and rewritten and which includes a first transparent substrate having a wobbling guide groove which is spirally formed thereon at a pitch; a first dielectric layer located overlying the first transparent substrate and having an optical thickness of from 80 nm to 200 nm; a phase-change recording layer located overlying the first dielectric layer and having an optical thickness of from 20 to 50 nm when the recording layer is in an erased state; a second dielectric layer located overlying the recording layer and having an optical thickness of from 10 nm to 70 nm; a reflection layer located overlying the second dielectric layer; optionally a third dielectric layer located between the second dielectric layer and the reflection layer; and a second transparent substrate located overlying the reflection 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 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: 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 optical information recording method including: irradiating a recording medium with laser light, wherein 0 signals having width nT are recorded or rewritten using continuous laser light having a power level Pe, and 1 signals having width nT are recorded or rewritten using a light pulse train having a first pulse portion fp having power Pw and width xT (T: clock time), a multi-pulse portion mp in which a number (n?n?) of high level pulses each having power Pw? and width yT, and, if (n?n?)>1, a low level pulse which has power Pb and width (1?y)T are applied, and an end pulse portion ep having power Pb? and width zT, wherein n and n? are a positive integer (n>n?), and wherein each of Pw and Pw? is greater than Pe, Pe is greater than each of Pb and Pb?, and at least one of x, y and z is in a range as follows: 0.35?x?0.75, 0.30?y?0.55, 0.35?z?0.70.

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 information recording method including irradiating an optical information recording medium containing a phase change recording layer on a substrate having a guide groove with continuous light of a laser beam having an erase power level Pe to determine a transition linear velocity Vo defined as a minimum linear velocity above which the following relationship is satisfied: Rr=Ra/Rb<1, wherein Rr represents a reflection light intensity ratio, and Ra and Rb represent a reflection light intensity measured after and before the irradiation of the optical information recording medium with the continuous light, respectively, prior to recording information in the optical information recording medium.

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.