摘要:
A magneto-optical recording medium has a recording layer whereon information is magneto-optically recorded. A readout layer is provided on the recording layer. The readout layer has a compensating temperature that is located between room temperature and the Curie temperature. In the readout layer, upon an application of a light beam, the in-plane magnetization occurs at room temperature and a transition from the in-plane magnetization to vertical magnetization occurs as the temperature of the irradiated area of the readout layer rises above a predetermined temperature. By employing this magneto-optical recording medium, with an application of a light beam that is intensity modulated into two levels, only a spot having a temperature not less than a predetermined temperature is involved in the reproduction; therefore, a recorded bit with a size smaller than the diameter of the light beam can be reproduced, thereby greatly increasing the recording density. Further, the level of the reproduced signals is increased, and crosstalk from the adjoining tracks is reduced; thus, information recording and overwriting can be conducted more easily.
摘要:
A recording and reproducing device for a magneto-optical card includes an optical head for irradiating a magneto-optical recording medium of a magneto-optical card placed into the device with a laser beam. A magnetic field generator applies a biased magnetic field to the magneto-optical recording medium, and an optical system manipulating mechanism for the optical system of the above-mentioned optical head varies the spot irradiated by the laser beam. The optical head is fixed to the main frame of the device. The magneto-optical card is also supported where it is irradiated by the laser beam emitted from the optical head. The magneto-optical card is moved in a plane parallel to the surface of the magneto-optical card for rough searching and then a part of or the whole magnetic field generator is moved to come into contact with the magneto-optical card to stop the vibration of the magneto-optical card. The spot to be irradiated by the laser beam is then varied by means of the optical system of the optical head.
摘要:
An optical recording medium, which is used as an optical disc, optical card or the like for optically recording, reproducing, erasing and the like, includes a center substrate having formed on at least one side thereof recesses and/or protrusions. Recording films are formed on both sides thereof and transparent protective plates bonded to these recording films respectively. This arrangement substantially eliminates warping of the substrates constituting the optical recording medium and exfoliation of substrates or the like even when the optical recording medium is subjected to sudden changes in temperature. This optical recording medium demonstrates enhanced optical performance and protective effect. The selecting of the transparent protective plate is simplified because the forming recesses and/or protrusions is not a factor. By producing an optical recording medium utilizing the above features, the carrier-to-noise ratio and isotropy of the medium is improved.
摘要:
A magneto-optical head wherein a light flux, which is reflected from a recording medium, is separated into its central portion and remaining portion. The central light flux portion is only used as a magneto-optical signal while the remaining light flux portion is only used as an optical servo signal.
摘要:
A magneto-optical recording apparatus of the present invention is provided with an objective lens for focusing a light beam onto a magneto-optical recording medium. A pair of magnets is disposed on opposite sides of the magneto-optical recording medium and apply a writing magnetic field onto a portion of the magneto-optical recording medium that has been irradiated by the light beam while applying an initializing magnetic field greater than the writing magnetic field onto a portion apart from that irradiated by the light beam.
摘要:
A magnetooptical storage element comprising a recording layer of a multi-layered structure including a reflecting film, said reflecting film being made of metals or metalloids having a low thermal conductivity coefficient.
摘要:
An intermediate layer is formed between a memory layer and a writing layer. The intermediate layer shows in-plane magnetization at room temperature, and perpendicular magnetization within a temperature range within which the coercive force of the memory layer is lower than that of the writing layer. The Curie point of the intermediate layer is lower than that of the memory layer. Like a conventional method, light-intensity modulation overwriting is performed by irradiating laser light whose intensity has been modulated between high level and low level while applying a recording magnetic field after performing an initialization. Even when there are variations in the raised temperature by the irradiation of laser light of high level, it is possible to perform stable overwriting with light-intensity modulation by satisfactorily restraining the exchange forces between the intermediate layer and the writing layer from causing coupling.
摘要:
A magneto-optical recording medium includes a first magnetic layer, a second magnetic layer and a third magnetic layer respectively made of rare earth-transition metal alloys. The first magnetic layer has a perpendicular magnetization in a temperature range between room temperature and its Curie temperature. The second magnetic layer has its Curie temperature higher than that of the first magnetic layer, and coercive force thereof at room temperature is nearly zero. The third magnetic layer has a perpendicular magnetization in a temperature range between room temperature and its Curie temperature. The Curie temperature of the third magnetic layer is higher than the Curie temperature of the first magnetic layer. The coercive force of the third magnetic layer at room temperature is lower than that of the first magnetic layer. The compensation temperature of the third magnetic layer is higher than that of the second magnetic layer. Having the above arrangement, an overwriting is permitted on the magneto-optical recording medium, and an initializing magnetic field and a recording magnetic field in a magneto-optical recording and reproducing device are set in the same direction.
摘要:
A magneto-optical disk cartridge includes a magnet which is magnetized substantially parallel to a surface of a magneto-optical disk for generating an initializing magnetic field. This structure permits a reduction in the thickness of the magneto-optical disk cartridge.
摘要:
A magneto-optical recording medium includes a first magnetic layer, a second magnetic layer and a third magnetic layer respectively made of rare-earth-transition metal alloys which are laminated in this order. The first magnetic layer has a perpendicular magnetization in a temperature range between room temperature and its Curie temperature. The second magnetic layer made of GdFeCo is set such that its Curie temperature is higher than the Curie temperature of the first magnetic layer, coercive force thereof at room temperature is nearly zero, and that it has an in-plane magnetization at room temperature and a transition occurs therein from the in-plane magnetization to the perpendicular magnetization at above a predetermined temperature. The third magnetic layer is set such that it has a perpendicular magnetization in a temperature range of room temperature and its Curie temperature, its Curie temperature is higher than the Curie temperature of the first magnetic layer, and coercive force thereof at room temperature is smaller than the coercive force of the first magnetic layer.