Abstract: An optical recording medium having a structure comprising at least a first substrate, a first recording layer capable of optical recording, a first reflection layer, an intermediate layer, a second recording layer capable of optical recording, a second reflection layer and a second substrate in this order from a side on which recording, reproducing or recording and reproducing laser light is applied, wherein the intermediate layer is composed of a resin having a glass transition temperature of 90° C. or greater.

Abstract: A rewritable optical recording medium includes a segmented groove area in which the groove track is segmented along a rotating direction of the recording medium by groove non-forming portions to form a plurality of groove portions; and a continuous groove area in which a continuous groove is formed, the continuous groove having a groove width smaller than a groove width in the segmented groove area.

Abstract: The present invention provides an optical recording medium, in which levels of wobble signals extracted from a recording area formed snakily, a reproduction exclusive area and an impossible area are maintained constant. On DVD-RW, groove tracks are snakily formed on a groove section on which recording information is recorded, and pit strings where a plurality of phase pits wave are arranged on the impossible area and the reproduction exclusive area which prevent illegal copying. On the respective areas, pit depths (groove depths), duty of the pit strings and wobbling amplitudes are set according to predetermined conditions so that the output levels of the wobble signals extracted based on the wobbling amplitudes can be maintained constant on the respective areas. As a result, synchronous control can be made accurately at the time of recording and reproduction on/from the DVD-RW.

Abstract: A groove track and a land track are alternately and spirally formed on an information recording medium. On the land track neighboring the groove track, pre-information indicating position information of a track on a disc is formed as a prepit. On the information recording medium, an embossed area is formed so that information about a copyright and for preventing an illegal copy cannot be rewritten. In the embossed area, an embossed configuration including a pit and a space of predetermined depths is formed. The prepit in the embossed area is formed so that the prepit has an optimized configuration according to a pit length and a space length in the embossed area which the prepit neighbors. Consequently, interference between the embossed configuration and the prepit can be prevented even in a case that the prepit is formed in addition to the embossed configuration in the embossed area.

Abstract: The present invention provides an optical recording medium, in which levels of wobble signals extracted from a recording area formed snakily, a reproduction exclusive area and an impossible area are maintained constant. On DVD-RW, groove tracks are snakily formed on a groove section on which recording information is recorded, and pit strings where a plurality of phase pits wave are arranged on the impossible area and the reproduction exclusive area which prevent illegal copying. On the respective areas, pit depths (groove depths), duty of the pit strings and wobbling amplitudes are set according to predetermined conditions so that the output levels of the wobble signals extracted based on the wobbling amplitudes can be maintained constant on the respective areas. As a result, synchronous control can be made accurately at the time of recording and reproduction on/from the DVD-RW.

Abstract: A phase change type information storage medium is provided, which achieves high-speed recording/reproduction. A DVD-RW disc having a substrate formed with grooves, lands, and land pre-pits, on which are laminated a first dielectric layer, a phase-change recording layer, a second dielectric layer, a reflective layer, and an overcoat layer. The disc is rotated at a 3.49-7.0 m/sec linear speed while being irradiated with a laser beam of 600-700 nm wavelength focused by an objective lens of 0.55-0.7 numerical aperture to the phase-change recording layer from the substrate side. The phase-change recording layer is made of a Ge-In-Sb-Te material, and the reflective layer is made of an Ag-Nd-Cu material. The first dielectric layer has a 65-85 nm thickness, the phase-change recording layer has a 10-20 nm thickness, the second dielectric layer has a 13-23 nm thickness, and the reflective layer has a 100-225 nm thickness.

Abstract: An optical recording medium is provided which comprises: a substrate including concentrically or spirally formed grooves each having a V-shaped cross section; a first dielectric layer formed on the substrate; a phase-change recording layer formed on the first dielectric layer; a second dielectric layer formed on the phase-change recording layer; and a metallic reflecting layer formed on the second dielectric layer. In particular, the optical recording medium is so formed that an objective lens having an aperture number of 0.55-0.70 can be used and a laser beam having a wavelength of 600-700 nm and passing through the objective lens is passed through the substrate and then converged on the recording layer, thereby recording or reproducing information on the recording layer in areas corresponding to the grooves.

Abstract: A recording medium includes pairs of groove tracks and land tracks having periodically formed bent portion provided side by side on a substrate, a plurality of land prepits previously formed on the land tracks and carrying information about the groove tracks, and a recording layer formed on at least the groove tracks and the land tracks. The land prepits have a radius of mean curvature smaller than a radius of mean curvature of sides of the groove tracks in land-prepit absent regions of the land prepits and are defined by curved surfaces continuously extending from the sides of the groove tracks. Those sides of the groove tracks which face the continuous curved surfaces of the land prepits are curved surfaces that stricture the groove tracks. The depth of the land prepit is larger than that of the groove track.

Abstract: A rewritable optical recording medium includes a segmented groove area in which the groove track is segmented along a rotating direction of the recording medium by groove non-forming portions to form a plurality of groove portions; and a continuous groove area in which a continuous groove is formed, the continuous groove having a groove width smaller than a groove width in the segmented groove area.

Abstract: A rewritable optical recording medium includes a segmented groove area in which the groove track is segmented along a rotating direction of the recording medium by groove non-forming portions to form a plurality of groove portions; and a continuous groove area in which a continuous groove is formed, the continuous groove having a groove width smaller than a groove width in the segmented groove area.

Abstract: An optical recording medium is provided which comprises: a substrate including concentrically or spirally formed grooves each having a V-shaped cross section; a first dielectric layer formed on the substrate; a phase-change recording layer formed on the first dielectric layer; a second dielectric layer formed on the phase-change recording layer; and a metallic reflecting layer formed on the second dielectric layer. In particular, the optical recording medium is so formed that an objective lens having an aperture number of 0.55-0.70 can be used and a laser beam having a wavelength of 600-700 nm and passing through the objective lens is passed through the substrate and then converged on the recording layer, thereby recording or reproducing information on the recording layer in areas corresponding to the grooves.

Abstract: A recording medium includes pairs of groove tracks and land tracks having periodically formed bent portion provided side by side on a substrate, a plurality of land prepits previously formed on the land tracks and carrying information about the groove tracks, and a recording layer formed on at least the groove tracks and the land tracks. The land prepits have a radius of mean curvature smaller than a radius of mean curvature of sides of the groove tracks in land-prepit absent regions of the land prepits and are defined by curved surfaces continuously extending from the sides of the groove tracks. Those sides of the groove tracks which face the continuous curved surfaces of the land prepits are curved surfaces that stricture the groove tracks. The depth of the land prepit is larger than that of the groove track.

Abstract: A rewritable optical recording medium includes a segmented groove area in which the groove track is segmented along a rotating direction of the recording medium by groove non-forming portions to form a plurality of groove portions; and a continuous groove area in which a continuous groove is formed, the continuous groove having a groove width smaller than a groove width in the segmented groove area.

Abstract: The present invention provides an optical recording medium, in which levels of wobble signals extracted from a recording area formed snakily, a reproduction exclusive area and an impossible area are maintained constant. On DVD-RW, groove tracks are snakily formed on a groove section on which recording information is recorded, and pit strings where a plurality of phase pits wave are arranged on the impossible area and the reproduction exclusive area which prevent illegal copying. On the respective areas, pit depths (groove depths), duty of the pit strings and wobbling amplitudes are set according to predetermined conditions so that the output levels of the wobble signals extracted based on the wobbling amplitudes can be maintained constant on the respective areas. As a result, synchronous control can be made accurately at the time of recording and reproduction on/from the DVD-RW.