Abstract: A method and apparatus for identifying an optical information storage medium, the method of identifying the optical information storage medium loaded into an apparatus for reproducing/recording the optical information storage medium including: moving an object lens at a predetermined velocity in a first direction or a second direction while the optical information storage medium is loaded; generating a sum signal by adding magnitudes of beams reflected by the optical information storage medium and condensed by an optical detector; measuring a first time period during which the sum signal has a value greater than a first level; and detecting a thickness of data layers of the optical information storage medium based on the first time period, wherein the thickness of the data layers corresponds to the type of the optical information storage medium.

Abstract: An optical pickup apparatus is equipped with a light emitting device, a first objective lens for focusing a laser beam emitted from the light emitting device onto a first optical disc, a second objective lens for focusing the laser beam emitted from the light emitting device onto a second optical disc, a light receiving device for receiving the laser beam reflected by the first or second optical disc, and an optical system for dividing the laser beam emitted from the light emitting device into a beam for the first objective lens and a beam for the second objective lens. The optical pickup apparatus is capable of performing at least either recording or reproduction on/from two kinds of information recording/reproduction media that are different from each other in thickness of substrate using a laser beam emitted from the identical light emitting device, and is small in size.

Abstract: There is provided an objective lens used for an optical information recording/reproducing device for recording information to and/or reproducing information from two types of optical discs, by selectively using one of two types of substantially collimated light beams including first and second light beams. When wavelengths of the first and second light beams are respectively represented by ?1 (nm) and ?2 (nm), ?1<?2 is satisfied. The objective lens includes a first optical element, and a second optical element made of material different from that of the first optical element. The first and second optical elements are cemented via a cementing surface. Further, the objective lens is configured to satisfy a condition: 0.006 < { ( nR ? ? 2 - nR ? ? 1 ) - ( nB ? ? 2 - nB ? ? 1 ) } × ? [ { ( k ? ? 2 r ? ? 2 3 ) + 8 × A ? ? 42 } × f ? ? 1 3 + 2.29 ] < 0.

Abstract: A magneto-optical medium has a recording layer having a plurality of columns extending in a lamination direction, and a reproduction layer which is placed below the recording layer and which functions as a nucleus for the columns.

Abstract: A description is given of a multi-stack optical data storage medium (20) for rewritable recording using a focused radiation beam (30) entering through an entrance face (16) of the medium (20) during recording. The medium (20) has a substrate (1). Deposited on a side thereof is a first recording stack (2) with a phase-change type recording layer (6). The first recording stack (2) is present at a position most remote from the entrance face (16). At least one further recording stack (3), with a phase-change type recording layer (12) is present closer to the entrance face (16) than the first recording stack (2). A metal reflective layer of Cu, transparent for the radiation beam (30), is present in the further recording stack (3) and has a thickness between 2 and 10 nm. A transparent spacer layer (9) is present between the recording stacks (2, 3).

Abstract: A magneto-optical storage medium that protects against the effects of cross-talk, making it possible to further reduce the level of track density, and which also makes it possible to conduct high-density recording/playback with a reduced magnetic field for erasure and a favorable level of playback signal quality. More specifically, a magneto-optical storage medium, which includes at least the following laminated layers, in the following order: a playback layer, a non-magnetic layer, a transfer layer, a cut-off layer, and a recording layer. The playback layer preferably displays easy in-plane magnetization characteristics within the monolayer at room temperature, and the transfer layer and the recording layer each have easy magnetization characteristics in the vertical direction of the monolayers at room temperature when each layer is considered as a monolayer.

Abstract: An information recording medium including an information recording film made of an exchange-coupled multilayer film capable of magnetically reproducing a recorded information, wherein the exchange-coupled multilayer film has a coercive force which is not substantially changed at a temperature ranging from room temperature to approximately 65° C., the product of 55 Gauss ?m or more of a remnant magnetic flux density and a film thickness, and includes at least a transition metal-rich rare earth-transition metal amorphous alloy layer and a rare earth-rich rare earth-transition metal amorphous layer.

Abstract: The disclosure relates to a device for controlling magnetization reversal in a controlled ferromagnetic system such as a magnetic memory element, without using an external magnetic field, wherein it comprises between two flat electrodes a magnetic control part comprising, starting from the first electrode, a first ferromagnetic layer, a non-magnetic layer, and a second ferromagnetic layer, and the second of said two flat electrodes, the thickness of said second ferromagnetic layer being less than that of said first layer, and the thickness of said second electrode being sufficiently small to enable magnetic coupling between said second ferromagnetic layer and the system controlled by the control device.

Abstract: Disclosed are magneto-optical recording media including at least a reflection layer, a recording layer and a dielectric layer laminated on a substrate in this order, wherein the thickness of the dielectric layer is not less than 140 nm or wherein the dielectric layer is provided by the lamination of upper dielectric layer and lower dielectric layer in which the thermal conductivity of the upper dielectric layer is higher than that of the lower dielectric layer. By arranging the thickness of the dielectric layer in a specific range, the surface roughness of a media in not more than 1.5 nm, and providing a reflection layer composed of a noble metal alloy, achieved is a magneto-optical recording medium able to record constantly in near-field magneto-optical recording, suitable for narrow track pitch, and having excellent SNR, resolution, and recording sensitivity.

Abstract: An information recording medium comprising an information recording film formed on a base on which regular depressions and projections having Ra of 0.1 to 1.5 nm have been formed, the information recording film containing as a major component a rare earth-transition metal amorphous alloy capable of magnetically reproducing a recorded information.

Abstract: A magnetooptical recording medium comprising at least a reproduction layer, an intermediate layer, a connection layer and a recording layer, wherein the reproduction layer and intermediate layer have a slant magnetic direction in a non-magnetic field, and the connection layer is composed of a layer non-magnetic at room temperature by itself which is induced to exhibit magnetism by contact with a magnetic layer.

Abstract: An MO disk includes a readout layer, an intermediate layer and a recording layer each of which is made of a rare earth-transition metal amorphous material. The MO disk also includes a fourth magnetic layer formed on the recording layer and made of a rare earth-transition metal amorphous magnetic material containing Gd. The fourth magnetic layer has a rare earth metal magnetization-dominant composition and an axis of easy magnetization oriented longitudinally at room temperature. The axis of easy magnetization is changed to be oriented perpendicularly to the fourth magnetic layer as the temperature of the fourth magnetic layer rises to the Curie temperature of the fourth magnetic layer.

Abstract: A magneto-optical recording medium, which is for recording and reproduction of information by focusing of light of a wavelength/numerical aperture of about 1000 nm or less, has a light transmitting first dielectric layer having a first surface to which light strikes. A magneto-optical recording layer is formed on a back surface of the first surface of the first dielectric layer. A light transmitting metal layer is formed on the magneto-optical recording layer to a predetermined thickness required for dispersion of heat (about 10 nm or more) from the magneto-optical recording layer and having a larger heat conductivity than the magneto-optical recording layer. A light transmitting second dielectric layer is formed on the light transmitting metal layer. A metal reflective layer is formed on the second dielectric layer and reflects the light.

Abstract: An optical recording/reproducing apparatus accessing a recording layer of an optical rotating recording medium using an accessing means positioned a predetermined gap away from a surface of said optical rotating recording medium and mounted with an object lens, wherein a thickness of a protective transparent layer of said optical rotating recording medium, a ratio of a defect area with respect to a beam spot area, and the above predetermined gap are values determined by the conditions defined in the following inequalities: G 1 ≤ t · k ⁢   ⁢ π × tan ⁢ { sin - 1 ⁡ ( NA n )

Abstract: A magneto-optical recording medium including a magnetic recording layer for recording information and a magnetic reproducing layer provided on the magnetic recording layer for reading information. The magnetic reproducing layer is separated into a first reproducing layer having a first composition and a second reproducing layer having a second composition slightly different from the first composition. The first and second reproducing layers have the same principal components. By changing a ratio in film thickness between the first and second reproducing layers, variations in composition of the first and second reproducing layers can be corrected.

Abstract: Front surface magneto-optical (FSMO) information storage and retrieval media having improved tribological properties when used in high-density storage devices employing very small head flying heights are formed by providing an ultra-thin, protective flash layer overcoat (FLO)/lubricant topcoat layer system on the media surface. Embodiments of the present invention include forming the FLO layer of an amorphous, abrasion-resistant, carbon-based, diamond-like material not greater than about 10 Å thick and selected from CNx, CHx, and CNxHy, and providing the lubricant topcoat on the FLO layer as an about 15-25 Å thick layer of a fluoropolyether or perfluoropolyether material, e.g., perfluoropolyethylene (PFPE).

Abstract: A data storage system including a source of heat, a substrate, a storage layer, a lubricant layer, a flying head, and a dielectric layer is disclosed. The dielectric layer is disposed between the lubricant layer and the storage layer. The flying head is disposed above the lubricant layer. The dielectric layer has a heat capacity that is sufficient to generate a temperature gradient between the storage layer and the lubricant layer so as to reduce lubricant evaporation onto the flying head.