Abstract: A magnetic lens has a reproducing layer and a magnetic slit. When the leak magnetic field Hlk of a recording magnetic domain on a recording disk exceeds the coercive force He of the magnetic slit, the magnetization in the magnetic slit is inverted into the same direction as that of the magnetization of the recording magnetic domain. Transition occurs from the in-plane magnetization to the perpendicular magnetization in a magnified area of the reproducing layer in which the temperature exceeds the critical temperature Tcr. The upward magnetization in the magnetic slit is transferred thereto. The magnetization information on the recording magnetic domain is reproduced with amplified signal intensity on the basis of the magneto-optical effect by detecting the reflected light beam of the reproducing light beam from the magnified area. A plurality of minute magnetic domains contained in an object can be detected respectively at a high sensitivity in an independent manner.

Abstract: A magneto-optical recording medium comprises, on a substrate, a dielectric layer, a GdFeCo reproducing layer, a non-magnetic layer, and a TbFeCo recording layer. Upon reproduction, a DC magnetic field Hex is applied in the recording direction, and a reproducing light beam is radiated while being modulated to have a low power and a high power in synchronization with a reproducing clock. The reproducing layer is a magnetic film which changes from in-plane magnetization into perpendicular magnetization at a critical temperature Tcr, which has a compensation temperature Tcomp between room temperature and a Curie temperature Tc, and which satisfies Troom<Tcr<Tcomp<Tco<Tc in relation to a Curie temperature Tco of the recording layer. Magnetic domain transfer and magnetic domain magnification occur if the transfer magnetic field of the recording layer and the coercive force of the reproducing layer have the relationship of relative magnitude as shown in FIG.

Abstract: A plate spring is provided on a back surface of a shutter of a cartridge. When the shutter is closed, the plate spring presses a disk in a cartridge case against an inner wall surface of a lower case so that the disk is immovable in the case. When the shutter is open, the plate spring is retracted into a space between an inner surface of the shutter and a surface of an upper case. The disk is supported immovably and uniformly in the cartridge. Therefore, deformation such as warpage of the disk hardly occurs. Even when the cartridge is stored in any posture, it is possible to avoid deformation such as warpage and flexure of the disk in the cartridge during the storage.

Abstract: A magnetic lens has a reproducing layer and a magnetic slit. When the leak magnetic field Hlk of a recording magnetic domain on a recording disk exceeds the coercive force He of the magnetic slit, the magnetization in the magnetic slit is inverted into the same direction as that of the magnetization of the recording magnetic domain. Transition occurs from the inplane magnetization to the perpendicular magnetization in a magnified area of the reproducing layer in which the temperature exceeds the critical temperature Tcr. The upward magnetization in the magnetic slit is transferred thereto. The magnetization information on the recording magnetic domain is reproduced with amplified signal intensity on the basis of the magneto-optical effect by detecting the reflected light beam of the reproducing light beam from the magnified area. A plurality of minute magnetic domains contained in an object can be detected respectively at a high sensitivity in an independent manner.

Abstract: A magnetic lens has a reproducing layer and a magnetic slit. When the leak magnetic field Hlk of a recording magnetic domain on a recording disk exceeds the coercive force Hc of the magnetic slit, the magnetization in the magnetic slit is inverted into the same direction as that of the magnetization of the recording magnetic domain. Transition occurs from the in-plane magnetization to the perpendicular magnetization in a magnified area of the reproducing layer in which the temperature exceeds the critical temperature Tcr. The upward magnetization in the magnetic slit is transferred thereto. The magnetization information on the recording magnetic domain is reproduced with amplified signal intensity on the basis of the magneto-optical effect by detecting the reflected light beam of the reproducing light beam from the magnified area. A plurality of minute magnetic domains contained in an object can be detected respectively at a high sensitivity in an independent manner.

Abstract: A plate spring is provided on a back surface of a shutter of a cartridge. When the shutter is closed, the plate spring presses a disk in a cartridge case against an inner wall surface of a lower case so that the disk is immovable in the case. When the shutter is open, the plate spring is retracted into a space between an inner surface of the shutter and a surface of an upper case. The disk is supported immovably and uniformly in the cartridge. Therefore, deformation such as warpage of the disk hardly occurs. Even when the cartridge is stored in any posture, it is possible to avoid deformation such as warpage and flexure of the disk in the cartridge during the storage.

Abstract: A plate spring is provided on a back surface of a shutter of a cartridge. When the shutter is closed, the plate spring presses a disk in a cartridge case against an inner wall surface of a lower case so that the disk is immovable in the case. When the shutter is open, the plate spring is retracted into a space between an inner surface of the shutter and a surface of an upper case. The disk is supported immovably and uniformly in the cartridge. Therefore, deformation such as warpage of the disk hardly occurs. Even when the cartridge is stored in any posture, it is possible to avoid deformation such as warpage and flexure of the disk in the cartridge during the storage.

Abstract: A magneto-optical recording medium comprises, on a substrate, a dielectric layer, a GdFeCo reproducing layer, a non-magnetic layer, and a TbFeCo recording layer. Upon reproduction, a DC magnetic field Hex is applied in the recording direction, and a reproducing light beam is radiated while being modulated to have a low power and a high power in synchronization with a reproducing clock. The reproducing layer is a magnetic film which changes from in-plane magnetization into perpendicular magnetization at a critical temperature Tcr, which has a compensation temperature Tcomp between room temperature and a Curie temperature Tc, and which satisfies Troom<Tcr<Tcomp<Tco<Tc in relation to a Curie temperature Tco of the recording layer.

Abstract: Scratches on the recording disk caused by sliding of a disk cartridge shutter is prevented by slidably inserting first and second shutters between a tray and a case on the opposite side to a recording disk accommodating portion of the tray. The first shutter simultaneously opens and closes a case side driving shaft insert hole, a case side head insert hole, a tray side driving shaft insert hole, and a tray side head insert hole. The second shutter opens and closes a terminal hole. The second shutter is opened independently of the first shutter and is held in a position so that the case side driving shaft insert hole, the case side head insert hole, the tray side driving shaft insert hole, and the tray side head insert hole are not closed. Closing the first shutter, however, causes the second shutter to also close.

Abstract: A disk cartridge is provided with an improved opening/closing slider mechanism which is small in size for positive opening/closing operation for a shutter. The disk cartridge has a front insertion side edge which has a reinforcement portion with guide rail mechanism in proximity thereto. The slider mounted on the guide rail mechanism has a longitudinally extending front face portion to the reverse side of which are integrated a two-sectioned rear face portion and connecting portion, one of each section being disposed in an end portion of the front face portion, so as to form grooves interacting with the guide rail mechanism.

Abstract: An optical recording disc which includes a pair of recording disc substrates opposed to each other with a space there between with a hub situated at the central portion of the disc substrates so that there is formed the closed space between the disc substrates, thereby providing a dual sided recordable optical recording disc. The hub may be formed by a pair of hub halves. There is disposed an annular inner spacer and annular outer space around the hub so as to separate the pair of recording disc substrates.

Abstract: An apparatus for producing an optical data recording medium comprising a turn table adapted to support a substrate of the recording medium and a nozzle for dropping a coating liquid onto the substrate, the coating liquid dropped on the substrate being spread over the substrate by a rotational force of the turn table to form a coating layer, the apparatus being provided with a gas flow suppressing type housing which is partitioned off from the atmosphere so as to suppress the convection current flowing, due to the rotation of the turn table, toward a central portion of the substrate and further toward the outer circumferential portion thereof along a top surface of the substrate and to suppress the evaporation of a solvent of the coating liquid into the atmosphere, the nozzle being arranged above the inner circumferential portion of the substrate with its end portion being directed to the outer circumferential portion of the substrate, the end portion of the nozzle being inclined so as to form an angle less th

Abstract: A disc drive apparatus including a cartridge holder for detachably holding a disc cartridge, which is provided with a shutter slidingly moving in one direction from a closed position to open windows formed in an upper surface and a lower surface of a cartridge case, has a pair of elongated opening/closing arms rotatably mounted on the cartridge holder for moving the shutter in an opening direction by an inserting force of the disc cartridge into the cartridge holder.