Abstract: When the recording density of an optical information recording medium is increased, the disk structure becomes more complex; and when many recording layers are provided, the production margin and the production cost becomes problems. By using a substrate and a light-transmitting layer formed on the substrate and made of a material the light transmittance of which varies when irradiated with recording light, information can be recorded/reproduced, thereby realizing easy production of a high-density optical information recording medium at low cost.

Abstract: An optical information recording medium includes a substrate, n information recording layers provided on the substrate, and spacer layers, each of which is provided so as to be interposed between the information recording layers, wherein each of (n?1) or more of the information recording layers has a layer number information part that is formed in correspondence with one or more recording marks X and contains layer number information, where n represents an integer of not less than 2, and the layer number information is information used for determining which a given information recording layer is among the n information recording layers. Each recording mark X has a length in a circumferential direction longer than a length of a recording mark Y used for recording another information in the information recording layers.

Abstract: A method is provided for producing a multilayer information recording medium including two or more information recording layers and a space layer provided between adjacent information recording layers. The method includes the steps of: providing a photosensitive adhesive sheet (300) containing an ultraviolet curable oligomer and an adhesive polymer on a predetermined information recording layer (102), attaching a stamper substrate (111) having an uneven surface as an information surface to the photosensitive adhesive sheet so as to transfer information of the stamper substrate to the photosensitive adhesive sheet, curing the photosensitive adhesive sheet after the transfer of the information so as to cause the photosensitive adhesive sheet to be the space layer (103), and peeling off the stamper substrate from the space layer and subsequently forming another information recording layer (104) on the space layer.

Abstract: An optical disc production apparatus for producing a disc substrate with one or two signal layers including: a first signal layer forming mechanism for forming a first signal layer on a disc substrate (hereinafter, substrate); a layer forming mechanism which selectively forms a first reflection layer on the first signal layer and forms a second reflection layer on a second signal layer; a second signal layer forming mechanism which forms the second signal layer on the substrate on which the first reflection layer is formed on the first signal layer; a light transmission layer forming mechanism which forms a light transmission layer on the first/second reflection layer; a first transportation mechanism in a loop shape which is arranged close to each of the above-described constitutional element; a second transportation mechanism which is arranged closed to the first transportation mechanism, and which transports the substrate on which the first/second reflection layer is formed on the first signal layer to the

Abstract: The invention relates to a method for manufacturing a multi-layer information recording medium, including the steps of: forming a thin-film layer on an information surface of a substrate having the information surface; placing a photo-curing resin film and a light transmissive resin stamper on the first thin-film layer followed by pressing; curing the photo-curing resin film by allowing light to pass through the light transmissive resin stamper; forming an information surface by stripping the light transmissive resin stamper from the cured photo-curing resin film; and forming an information layer by covering the information surface with a thin-film layer, wherein the light transmissive resin stamper has a transfer surface used to form the information surface, and a metal thin film is formed on the transfer surface.

Abstract: An optical disc cutting apparatus capable of suppressing an unnecessary deflection component and unnecessary light intensity variation component and manufacturing a optical disc suitable for a high definition, high precision and high density optical disc.

Abstract: A manufacturing method for an optical data recording medium having a substrate with at least one signal recording layer and a resin layer for passing light, the manufacturing method includes: coating a radiation-curable resin on the substrate; and forming the resin layer by curing at least a part of the radiation-curable resin by increasing the rotational speed of the substrate to a first speed, then decreasing the rotational speed of the substrate, and emitting radiation while the rotational speed of the substrate is decreasing.

Abstract: A magneto-optical recording medium includes a substrate and a reproducing layer and a recording layer provided on the substrate. A recording magnetic domain is provided in the recording layer by heating the recording layer by irradiation with light and applying a recording magnetic field to the recording layer in such a manner that information is recorded in the recording layer. The recording layer is a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface, and the magnetic film holds the recording magnetic domain formed therein. The magneto-optical recording medium further comprises a intermediate layer and a reproducing aid layer between the reproducing layer and the recording layer. Saturated magnetization of the reproducing aid layer increases with an increase in the temperature of the reproducing aid layer.

Abstract: A process for producing an optical disk master, comprises the steps of forming a photoresist layer on a glass master, cutting the photoresist layer by projecting light beam onto the glass master having the photoresist layer thereon to expose the photoresist layer to light, developing the photoresist layer after the cutting step to form a hollow portion corresponding to the light-exposed portion, and carrying out an ion treatment by projecting ions onto the developed photoresist layer to decrease the thickness of the photoresist layer at the developed hollow portion to reach the prescribed depth by the ion-treatment.

Abstract: A method for manufacturing a multilayer information recording medium including a signal substrate, at least two information recording portions disposed on the signal substrate and a resin layer disposed between the information recording portions adjacent to each other is provided. The method includes forming the resin layer, and in the forming of the resin layer, a resin-containing coating is applied onto the signal substrate except for edge portions and of the signal substrate through openings of a screen, the signal substrate and a signal transfer substrate are attached to each other via the applied resin-containing coating at a pressure lower than atmospheric pressure, a resin contained in the applied resin-containing coating is cured to form the resin layer, and then the signal transfer substrate is peeled off from the resin layer.

Abstract: An optical disk medium (20), comprising an optical disk medium body (1) having a first layer (2), a second layer (2b) thinner than the first layer (2), a recording layer (2a) between the first layer (2) and the second layer (2b) and a center hold (3) at the center thereof and a hub (10) formed of a magnetic substance material, wherein the hub (10) is fixed to the optical disk medium body (1) so as to close the center hole (3) in the movable state relative to the optical disk medium body (1) within a specified range, the surface of the optical disk medium body (1) on the second layer (2b) side forms a light input surface, and a projection is not substantially formed on the surface of the optical disk medium body (1) on the light input surface side including the peripheral edge of the center hole (3), whereby since the second layer (2b) can be thinly and accurately formed, the optical disk medium suitable for high-density recording can be provided at a low cost.

Abstract: The object of the present invention is to provide an optical information recording medium which has tolerance to warping. To achieve the object above, an optical information recording medium 100 of the present invention includes at least one information recording layer 103 on a main surface of a substrate 101 and a light-transmitting layer 106. The substrate 101 includes a clamp area 105 and an information recording area 104 in accordance with the information recording layer 103. In the light-transmitting layer 106, the average thickness of a second area 106b corresponding to the clamp area 105 is thinner than the average thickness of a first area 106a corresponding to the information recording area 104.

Abstract: An optical information recording medium of the present invention includes: a substrate with at least one selected from the group consisting of a groove and a pit formed on one surface thereof; at least one information layer provided on the surfaces of the substrate, the information layer including at least one selected from the group consisting of a recording film and a reflective film; a resin layer provided on the information layer; and a light transmission layer provided on the resin layer. The resin layer includes a first resin film and a second resin film disposed in this order from the side of the light transmission layer, and when a water absorption rate of the first resin film is represented by A1 and a water absorption rate of the second resin film is represented by A2, A1 and A2 satisfy: A1>A2. The first resin film and the second resin film may have a different flexural modulus of elasticity.

Abstract: A high-definition and high-precision optical disc medium suitable for high density includes a recording layer which has an inner peripheral region extending radially outwardly from a central bore to a signal start boundary and a signal region extending radially outwardly from the signal start boundary. A light transmitting layer is disposed on the recording layer and the signal region of one face of the recording layer adjacent to the light transmitting layer occupies a laser beam incident face such that either reproduction or recording and reproduction of information is performed from the recording layer via the light transmitting layer. The inner peripheral region of the face of the recording layer is formed flat and a recess is formed, on one face of the optical disc medium opposite to the light transmitting layer, in an area corresponding to the inner peripheral region of the recording layer.

Abstract: A magneto-optical recording medium includes a substrate and a reproducing layer and a recording layer provided on the substrate. A recording magnetic domain is provided in the recording layer by heating the recording layer by irradiation with light and applying a recording magnetic field to the recording layer in such a manner that information is recorded in the recording layer. The recording layer is a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface, and the magnetic film holds the recording magnetic domain formed therein. The magneto-optical recording medium further comprises a intermediate layer and a reproducing aid layer between the reproducing layer and the recording layer. Saturated magnetization of the reproducing aid layer increases with an increase in the temperature of the reproducing aid layer.

Abstract: A magneto-optical recording medium includes a substrate and a reproducing layer and a recording layer provided on the substrate. A recording magnetic domain is provided in the recording layer by heating the recording layer by irradiation with light and applying a recording magnetic field to the recording layer so that information is recorded in the recording layer. The recording layer is a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface, and the magnetic film holds the recording magnetic domain formed therein.

Abstract: A magneto-optical recording medium includes a substrate and a reproducing layer and a recording layer provided on the substrate. A method for reproducing information from the magneto-optical recording medium includes increasing the temperature of the magneto-optical recording medium irradiated by laser light and included in an inside part of a light spot to a temperature range including a temperature at which the saturated magnetization of at least the recording layer or the reproducing aid layer is maximized, and reproducing the information only from a temperature region within the light spot where the information can be transcribed from the recording layer by a magnetic coupling force between the recording layer and the reproducing layer, by transcribing the recording magnetic domain from the recording layer onto the reproducing layer.

Abstract: An optical information recording medium of the present invention includes: a substrate with at least one selected from the group consisting of a groove and a pit formed on one surface thereof; at least one information layer provided on the surfaces of the substrate, the information layer including at least one selected from the group consisting of a recording film and a reflective film; a resin layer provided on the information layer; and a light transmission layer provided on the resin layer. The resin layer includes a first resin film and a second resin film disposed in this order from the side of the light transmission layer, and when a water absorption rate of the first resin film is represented by A1 and a water absorption rate of the second resin film is represented by A2, A1 and A2 satisfy: A1>A2. The first resin film and the second resin film may have a different flexural modulus of elasticity.

Abstract: As a magneto-optical recording medium capable of obtaining stable tracking servo signals with a narrow tracking pitch with less influences of cross talk and cross write, a magneto-optical recording medium is provided which comprises a plurality of recording/reproducing tracks and wobble pits for a sample servo, wherein each of the wobble pits is provided between two adjacent tracks and used commonly by the adjacent tracks.

Abstract: A magneto-optical recording medium includes a substrate and a reproducing layer and a recording layer provided on the substrate. A recording magnetic domain is provided in the recording layer by heating the recording layer by irradiation with light and applying a recording magnetic field to the recording layer in such a manner that information is recorded in the recording layer. The recording layer is a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface, and the magnetic film holds the recording magnetic domain formed therein. The magneto-optical recording medium further comprises a intermediate layer and a reproducing aid layer between the reproducing layer and the recording layer. Saturated magnetization of the reproducing aid layer increases with an increase in the temperature of the reproducing aid layer.