Abstract: An information recording medium (100) is provided with (i) a first information recording area wherein a first track for reproducing first information based on a first track pitch is formed by a laser beam, and (ii) a second information recording area wherein a second track for reproducing second information based on a second track pitch different from the first track pitch is formed by a laser beam. The groove shape of the first track is different from the groove shape of the second track.

Abstract: Provided is an optical recording medium comprising a substrate and a reflective layer, a first dielectric layer, a recording layer, a second dielectric layer and a light-transmission layer formed in this order on the substrate. The recording layer is decomposable by heat at a time of recording to achieve recording of the optical recording medium, and the optical recording medium further comprises a third dielectric layer between the second dielectric layer and the light-transmission layer.

Abstract: Provided is an extremely high-density optical recording medium with excellent jitter characteristics and good recording/reproducing characteristics. An optical recording medium 20 comprises a substrate 21 with a guide groove formed therein, a layer 23 with a light reflection function, a recording layer 22 comprising a dye as a main component with a light absorption function for a wavelength of recording/reproducing light in an unrecorded state, and a cover layer 24 capable of transmitting the recording/reproducing light incident to the recording layer 22, in the order mentioned; an interlayer 30 containing at least one element selected from the group consisting of Ta, Nb, V, W, Mo, Cr and Ti, is provided between the layer 23 with the light reflection function and the recording layer 22.

Abstract: An information recording medium having a recording track wherein the recording track includes a first recording region R1, a second recording region R2 and a recording region transition section Sx arranged between regions R1 and R2; a track pitch tp1, a groove width w1 and a groove depth d1 in region R1, and a track pitch tp2, a groove width w2and a groove depth d2 in region R2 satisfy formula (1), (2) and/or (3); the recording region transition section Sx includes a track pitch transition section Stp in which the track pitch changes from tp1 to tp2 and a groove shape transition section Sg in which the groove width changes from w1 to w2 and/or the groove depth changes from d1 to d2; and the track pitch transition section Stp and the groove shape transition section Sg at least partially overlap to share a region SL.

Abstract: By use of a substrate which can be stably formed and has a relatively small groove depth, a very high density optical recording medium having good recording/reading characteristics is provided. In an optical recording medium of a surface incidence type, in which a reflective layer, a recording layer containing a dye as a main component and a cover layer are sequentially formed on a substrate having guide grooves formed therein, a guide groove part on a far side from a plane of incidence of a recording/reading light beam on the cover layer is set as a recording groove part, and reflected light intensity in a recorded pit portion formed in the recording groove part is increased by a phase shift and is set higher than reflected light intensity in unrecorded.

Abstract: It is an object of the present invention to achieve a recording medium more excellent in preservation resistance than conventional optical recording media. To achieve the above object, the present invention provides an optical recording medium comprising a substrate and a reflective layer, a first dielectric layer, a recording layer, a second dielectric layer and a light-transmission layer formed in this order on the substrate, the recording layer being decomposable by heat at a time of recording to achieve recording of the optical recording medium, wherein the optical recording medium further comprises a third dielectric layer between the second dielectric layer and the light-transmission layer.

Abstract: An optical recording medium is provided which has excellent jitter characteristics and satisfactory recording/reproducing characteristics and is capable of extremely high-density recording. The optical recording medium 20 comprises a substrate 21 having a guide groove and the following layers formed on the substrate 21 in the following order: a layer 23 having a light-reflecting function, a recording layer 22 containing a specific porphyrin compound as a main component, and a cover layer 24 capable of transmitting a recording/reproducing light entering the recording layer 22, wherein when a portion of the guide groove at a side far from a surface where a recording/reproducing light beam enters the cover layer 24, is represented as a recording groove portion, then a recording pit portion formed in the recording groove portion, has a higher reflective optical intensity than the recording groove portion in an unrecorded state.

Abstract: Stable focus servo and tracking servo are realized in an information recording medium having a plurality of recording regions having different track pitches and groove shapes.

Abstract: Provided is an extremely high-density optical recording medium with excellent jitter characteristics and good recording/reproducing characteristics. An optical recording medium 20 comprises a substrate 21 with a guide groove formed therein, a layer 23 with a light reflection function, a recording layer 22 comprising a dye as a main component with a light absorption function for a wavelength of recording/reproducing light in an unrecorded state, and a cover layer 24 capable of transmitting the recording/reproducing light incident to the recording layer 22, in the order mentioned; an interlayer 30 containing at least one element selected from the group consisting of Ta, Nb, V, W, Mo, Cr and Ti, is provided between the layer 23 with the light reflection function and the recording layer 22.

Abstract: An information recording medium (100) is provided with (i) a first information recording area wherein a first track for reproducing first information based on a first track pitch is formed by a laser beam, and (ii) a second information recording area wherein a second track for reproducing second information based on a second track pitch different from the first track pitch is formed by a laser beam. The groove shape of the first track is different from the groove shape of the second track.

Abstract: An information recording medium (100) is provided with (i) a first information recording area wherein a first track for reproducing first information based on a first track pitch is formed by a laser beam, and (ii) a second information recording area wherein a second track for reproducing second information based on a second track pitch different from the first track pitch is formed by a laser beam. In the second track, a recording mark is previously recorded.

Abstract: The main object of the present invention is to provide a recording medium which makes high densification of information possible, particularly a write-once-read-many optical recording medium having good recording signal characteristics to a wide range of recording powers. The present invention is one to accomplish the above object by providing a recording medium having a recording layer, whereby recording is carried out by heating the recording layer, characterized in that the recording layer contains a substance A which decomposes at a temperature which the recording layer reaches when heated for recording, and a substance B which does not undergo a chemical reaction or phase change at a temperature which the recording layer reaches when heated for recording.

Abstract: An optical recording method to be used for recording at a high data transfer rate length-modulated marks on a recording medium by applying a recording laser beam locally to the recording medium. The recording laser beam has a writing power Pwi, is and a bias power Pbi. A record mark has a length of nT. With respect to at least two record marks, a pulse dividing number m is at least 2, and with respect to all record marks with m being at least 2, 2.5 is smaller than or equal to n/m, in a case where plural different record mark lengths are to be respectively formed by the same pulse dividing number m.

Abstract: The object of the present invention is to provide a technology which has high compatibility and can provide users with conveniences. A new system recording medium 100 has a center hole 112 formed on a recording disk 110 and a center hole 121 formed on a center hub 120, so that the recording medium 100 can respond to both an old system driving unit having a centering member coupling with the center hole 112 and a new system driving unit 300 having a second centering member 313 coupling with the center hole 121. Moreover, the old system recording medium is a recording medium providing a recording disk having a center hole incorporated in a cartridge having a center hub, and has a structure where the center hole is coupled both with a first centering member 312 of the new system driving unit 300 and with the centering member of the old system driving unit.

Abstract: By use of a substrate which can be stably formed and has a relatively small groove depth, a very high density optical recording medium having good recording/reading characteristics is provided. In an optical recording medium of a surface incidence type, in which a reflective layer, a recording layer containing a dye as a main component and a cover layer are sequentially formed on a substrate having guide grooves formed therein, a guide groove part on a far side from a plane of incidence of a recording/reading light beam on the cover layer is set as a recording groove part, and reflected light intensity in a recorded pit portion formed in the recording groove part is increased by a phase shift and is set higher than reflected light intensity in unrecorded.

Abstract: The object of the present invention is to provide a technology which has high compatibility and can provide users with conveniences. A new system recording medium 100 has a center hole 112 formed on a recording disk 110 and a center hole 121 formed on a center hub 120, so that the recording medium 100 can respond to both an old system driving unit having a centering member coupling with the center hole 112 and a new system driving unit 300 having a second centering member 313 coupling with the center hole 121. Moreover, the old system recording medium is a recording medium providing a recording disk having a center hole incorporated in a cartridge having a center hub, and has a structure where the center hole is coupled both with a first centering member 312 of the new system driving unit 300 and with the centering member of the old system driving unit.

Abstract: To provide a process for producing a laminated optical recording medium with improved production efficiency, with which in production of an optical recording medium by a 2P process, a resin forming an interlayer and a light transmitting stamper can easily be separated without applying any constrained load. A process for producing a laminated optical recording medium, which comprises applying a precursor of an ultraviolet-curing resin on a recording layer containing an organic dye formed on a polycarbonate substrate, disposing a polypropylene light transmitting stamper comprising a nonpolar member having a concavo-convex shape thereon, curing the ultraviolet-curing resin and then easily separating the light transmitting stamper without applying any constrained load so that the concavo-convex shape is transcribed on the resin layer.

Abstract: The object of the present invention is to provide a technology which has high compatibility and can provide users with conveniences. A new system recording medium 100 has a center hole 112 formed on a recording disk 110 and a center hole 121 formed on a center hub 120, so that the recording medium 100 can respond to both an old system driving unit having a centering member coupling with the center hole 112 and a new system driving unit 300 having a second centering member 313 coupling with the center hole 121. Moreover, the old system recording medium is a recording medium providing a recording disk having a center hole incorporated in a cartridge having a center hub, and has a structure where the center hole is coupled both with a first centering member 312 of the new system driving unit 300 and with the centering member of the old system driving unit.

Abstract: The main object of the present invention is to provide a recording medium which makes high densification of information possible, particularly a write-once-read-many optical recording medium having good recording signal characteristics to a wide range of recording powers. The present invention is one to accomplish the above object by providing a recording medium having a recording layer, whereby recording is carried out by heating the recording layer, characterized in that the recording layer contains a substance A which decomposes at a temperature which the recording layer reaches when heated for recording, and a substance B which does not undergo a chemical reaction or phase change at a temperature which the recording layer reaches when heated for recording.

Abstract: To provide an optical recording method to be used for recording at a high data transfer rate where the reference clock frequency is at least about 200 MHz and a linear velocity is about 40 m/sec. When recording mark length-modulated information is to be recorded on a recording medium by applying a recording laser beam locally to the recording medium, in order to form one record mark length of nT, m pieces of recording pulses ?iT (1?i?m) and m pieces of off-pulses ?iT (1?i?m), represented by: ?1T, ?1T, ?2T, ?2T, . . . , ?1T, ?1T, . . .