Abstract: According to an embodiment, a storage medium includes a transparent resin substrate having a concentric or spiral groove and a recording film formed on the groove on the transparent resin substrate, a recording mark being formed by irradiation of a laser beam, wherein a reproduction durability count in a case where reproduction is continuously carried out by a laser beam is 1,000,000 or more.

Abstract: According to one embodiment, in a storage medium, a ratio of a minimum value of an amplitude of a wobble detection signal to a track shift detection signal is set to be equal to or greater than a predetermined value.

Abstract: An information storage medium as an example of this invention includes a recording layer formed by a dye material having a predetermined sensitivity level or more to both a light beam having a first waveband and a light beam having a second waveband shorter than the first waveband. The recording layer includes a concentric management information area, and a concentric data area. The management information area includes a plurality of bar-like patterns formed by the light beam having the first waveband, and arranged in a circumferential direction. The plurality of bar-like patterns arranged in the circumferential direction form management information. The data area can record data by the light beam having the second waveband.

Abstract: An information storage medium according to an embodiment of the invention includes a concentric management information area. The management information area has a plurality of bar-like patterns in a circumferential direction which include an aggregate of a plurality of grooves or marks aligned in a radial direction. The plurality of bar-like patterns aligned in the circumferential direction form management information.

Abstract: According to this invention, a disc-like information storage medium has a concentric management information area and a concentric data area. The management information area includes a plurality of grooves aligned in a radial direction, a dye material applied to the plurality of grooves, and a plurality of bar-like patterns formed in a radial direction crossing the plurality of grooves and aligned in a circumferential direction. The data area includes a plurality of grooves aligned in the radial direction, and a dye material applied to the plurality of grooves. The plurality of bar-like patterns aligned in the circumferential direction include management information.

Abstract: In an optical disk system using a PRML identification system, a method for deriving an optimum recording wave in a short period of time is provided. Parameters of the recording wave are adjusted by using an evaluation value obtained by a signal evaluation method which is suitable for the PRML identification system as an index. In this case, as a parameter adjusting method, a plurality of adjusting methods are utilized.

Abstract: A write-once information recording disk has a transparent substrate having concentric or spiral grooves formed therein, and a recording film formed on the grooves on the transparent substrate, wherein the recording groove has an anion portion and a pigment portion, being formed of one organic pigment of which maximum absorption wavelength region from the wavelength of short wavelength laser light to be emitted to the recording film is present at the longer wavelength side, a recording mark is formed on the recording film by irradiation with short wavelength laser light, and the recording mark has a higher light reflectivity than the light reflectivity of the recording film before irradiation with the short wavelength laser light. Therefore, the write-once type optical disk has a so-called low-to-high characteristic, that is, the reflectivity is higher after recording than before recording.

Abstract: A recording material for a medium used for the recording film of a write-once type information recording disk equipped with a transparent resin substrate on which concentric or spiral grooves were formed and a recording film which was formed on the grooves, characterized in that it is formed by one organic coloring matter having an anion portion and a coloring matter portion in which the maximum absorption wavelength zone exists at a longer wavelength side than the wavelength of short wavelength laser beam irradiated on the recording film and forms a record mark on the recording film by irradiation of the short wavelength laser beam, and the record mark has a higher optical reflection coefficient than the optical reflection coefficient of the recording film before irradiation of the short wavelength laser beam. This material realizes so-called Low to High property.

Abstract: A write-once optical disk comprises a transparent resin substrate having a concentrically or spirally shaped groove and a land formed thereon, and a recording film formed on the groove and the land of the transparent resin substrate, a recording mark being formed by emission of a short-wavelength laser light beam. In addition, a light reflectivity of the recording mark portion formed by emission of the short wave laser light beam is higher than a light reflectivity obtained before emission of the short wavelength laser light beam, and a depth of the groove is in the range of 50 to 80 nm.

Abstract: A write-once information recording medium comprises a transparent resin substrate having a concentrically or spirally shaped groove and a land formed thereon, and a recording firm formed on the groove and the land of the transparent resin substrate, a recording mark being formed on the medium by emission of a short wavelength laser light, the recording medium having an L to H feature in which a light reflectivity of the recording mark portion formed by the emission of the short wavelength laser light is higher than a light reflectivity obtained before the emission of the short wavelength laser light.

Abstract: A write-once optical disk comprises a transparent resin substrate having a concentrically or spirally shaped groove and a land formed thereon, and a recording film formed on the groove and the land of the transparent resin substrate, a recording being formed on the medium by emission of a short-wavelength laser beam. Light reflectivity of the recording mark portion formed by emission of the short-wavelength laser light is set so as to be higher than the light reflectivity obtained before emission of the short-wavelength laser light, and the groove wobbles in a predetermined amplitude range.

Abstract: An optical disk according to the present invention has a guide groove formed with a width which is not less than 80 nm and not more than 170 nm in terms of a half-value width. A depth of the guide groove is formed within a range in which (n1?n2)·d1+n2·d2=(2m?1)·?/4 is ±15%, wherein n1 is a refractive index of a substrate, n2 is a refractive index of a recording film, ? is a wavelength of light beams used for recording and reproduction of information, d1 is a depth of the guide groove, d2 is a depth of the recording film positioned on the guide groove, and m is an integer (m=1, 2, 3, 4 . . . ).

Abstract: In an optical disk according to the present invention, “(G/T)×W” is specified in such a manner that a difference between a peak level and a noise level obtained from frequency characteristics of a doubled reproduction signal obtained by doubling a reproduction signal corresponding to reflected light beams acquired from application of light beams with a predetermined wavelength on a groove is maintained at not less than 19 dB as a result of evaluating the doubled reproduction signal by using the frequency characteristics of the doubled reproduction signal, wherein T (nm) is a central distance between the grooves, G (nm) is a width of the groove, and W (nm) is an amplitude of a wobble of the groove.

Abstract: An optical disk according to the invention has a lead-in area in which information concerning characteristics of an optical head for use in recording or reproducing the information and an optimum condition of a light beam for recording the information on the optical disk or reproducing the information from the optical disk are recorded.

Abstract: In a phase change optical recording medium, by determining heat conductivity relatively higher in one of interference layers on and under the recording layer, heat absorbed into the recording layer can be released moderately through an interference layer. Thereby, cross erasure caused by heating of adjacent tracks can be prevented, and at the same time, excessive heat radiation is prevented from a part of the recording layer nearer to the substrate to thereby maintain appropriate heat in the recording layer. As a result, cross-erasure is prevented, and data can be rewritten with the supply of typical recording/erasure power.

Abstract: An optical recording medium, which has a land and a groove on which a record mark is formed, comprises a transparent substrate, an inner protection layer formed on the substrate, a recording material layer formed on the inner protection layer and a reflection layer formed on the outer protection layer. The groove is formed to have a depth of .lambda./6 and the ratio of the thickness of the outer protection layer to the thickness of the recording material layer is set in a range between 0.8 and 1.2.

Abstract: An optical recording medium comprises a transparent substrate, an inner protection layer, a recording material layer, an outer protection layer, and a reflection layer, which are laminated in this order. In an in-groove recording mode, the ratio of the thickness of the recording material layer to the thickness of the outer protection layer is in a range between 0.52 and 0.95. In an on-land recording mode, the ratio of the thickness of the recording material layer to the thickness of the outer protection layer is in a range between 0.32 and 0.6.

Abstract: An optical recording medium comprises a transparent substrate, an inner protection layer, a recording material layer, an outer protection layer, and a reflection layer, which are laminated in this order. In an in-groove recording mode, the ratio of the thickness of the recording material layer to the thickness of the outer protection layer is in a range between 0.52 and 0.95. In an on-land recording mode, the ratio of the thickness of the recording material layer to the thickness of the outer protection layer is in a range between 0.32 and 0.6.

Abstract: According to this invention, there is provided an information recording medium including a substrate, a metal layer formed on the substrate, and a recording layer formed on the metal layer and being formed a recorded portion and a non-recorded portion by changing optical characteristics by radiating a recording light beam, wherein the recording layer contains GeSbTe, a reflectance of the recorded portion of the recording layer is higher than that of the non-recorded portion, and a reflectance of the non-recorded portion is not less than 10%. Focusing and tracking operations can be stably performed.

Abstract: A laser beam is radiated on a recording medium such as a phase transition type optical disk to change optical characteristics depending on a change in arrangement of atoms in a recording layer of the recording medium so as to repetitively record/erase information represented by the lengths of optical marks, the recording power of the laser beam radiated to record the information in the recording medium is changed stepwise in two or more power levels sequentially higher than an erasure power level of a laser beam radiated to erase the information recorded in the recording medium.