摘要:
An information recording and reproduction apparatus for a magnetically induced superresolution magneto-optical recording medium includes an optical head that emits a laser beam to a signal recording plane of the medium and detecting a laser beam reflected therefrom. The optical head includes a polarization plane rotary unit and a polarizing filter between a light source and an objective lens. The polarization plane rotary unit transmits the laser beam while rotating the direction of polarization of the laser beam. The polarizing filter allows the laser beam to be transmitted at the outer portion independent of the direction of polarization, and allows only the laser beam that is polarized in a particular direction to be transmitted at the inner portion. The polarization plane rotary unit is controlled so as to rotate the direction of polarization of the laser beam in a direction different from the particular direction in reproduction. Thus, the optical superresolution method is carried out with the inner portion of the laser beam for radiation blocked only in reproduction.
摘要:
The present invention provides a recording medium and an information recording/reproducing apparatus which permit recording and/or reproducing by a laser beam of optimized power for each recording medium. The recording medium is provided with a calibration region in addition to an information recording region. The calibration region has wobbles formed such that the amplitude of the waveform of a reproduced signal therefrom can change. Prior to recording to the information recording region, a signal is recorded in the calibration region by changing the laser power, and the recorded signal is immediately reproduced. The waveform of the reproduced signal is evaluated to determine optimum laser power for recording. At the time of reproducing, a signal previously recorded in the calibration region is reproduced while changing the laser power, and laser power optimum for reproducing is determined.
摘要:
A magneto-optic disk and a recording/reproduction device therefor adopt optical super-resolution to increase recording capacity. More specifically, the magneto-optic disk has an heat emitting layer (6) on a recording layer (4) and still preferably has an intermediate layer (8) between a reproduction layer (3) and the recording layer (4). The recording/reproduction device includes a circuit (33) for pulsing a laser beam to be radiated to the magneto-optic disk and still preferably includes a polarization rotating unit (50) and a polarizing filter (51) for blocking only the center of the laser beam in reproduction. The heat emitting layer (6) diffusing any heat generated by the laser beam, and the discontinuously radiated laser beam allow small recording domain. The laser beam having its center blocked forms smaller main lobe due to diffraction effect.
摘要:
A magneto-optic recording medium reproduction device includes a multi-clad, step index optical fiber, a semiconductor laser arranged on one end surface side of the optical fiber for providing laser beam to one end surface of the optical fiber, a photodetector arranged on one end surface side of the optical fiber and receiving laser beam from one end surface of the optical fiber, and a magnetic head for applying an alternating field to the magneto-optic recording medium. Since the other end surface of the optical fiber is arranged adjacent to the magneto-optic recording medium, an accurate signal can be reproduced even from an extremely small recorded domain. Furthermore, since an alternating field is applied to the magneto-optic recording medium, a domain transferred from a recording layer of the magneto-optic recording medium to a reproducing layer is expanded and a large reproduced signal can be obtained from the expanded domain.
摘要:
In magneto-optical recording medium, on a transparent substrate of polycarbonate resin, an SiN film having the thickness of 600 to 800 .ANG. and surface roughness Rmax of at most 10 nm is formed. On the SiN film, a GdFeCo reading layer having the thickness of 800 to 1200 .ANG. with Gd content of 30 to 36 at. % and Co content of 12 to 50 at. % is formed. On the reading layer, a TbFeCo recording layer of which Co content is 10 to 16 at. % is formed. The recording layer is a perpendicular magnetization film, and the reading layer is an in-plane magnetization film. At the time of reading, the reading and recording layers are heated, and the direction of magnetization of the recording layer is transferred to the reading layer only in the prescribed heated area. Information can be read only from the transferred portion, and thus a super resolution effect is obtained. When Kerr rotation angle .theta..sub.K is measured for the light reflected from the reading layer while the temperatures of the reading and recording layers are elevated, .theta..sub.K is approximately in proportion to Cth power of the elevated temperature t, wherein C is at least 8.0.
摘要:
A magneto-optical record medium and a reproducing apparatus for the same allow data reproduction having good characteristics by a simple structure. The magneto-optical record medium includes a plurality of first grooves (3) each having sidewalls, at least one of which is wobbled in accordance with address information; an address mark (21) formed by changing a width of a land located between second grooves connected to the first grooves; and third grooves wobbled cyclically, formed in a data portion magnetically storing data and connected to the second grooves. The reproducing apparatus reproduces the data from the magneto-optical record medium.
摘要:
The magneto-optical recording medium, including a transparent polycarbonate substrate, an interference layer made of SiN, a reading layer made of GdFeCo, a recording layer made of TbFeCo, an oxidation-preventing layer made of SiN, a irradiation layer made of Al and an ultraviolet-setting plastic layer, is disclosed. Each layer is deposited to a suitable thickness in the above-named order on the transparent polycarbonate substrate. The composition of each element in the reading layer and the recording layer is set to a suitable value to achieve acceptable characteristics. A high recording and reading density is achieved.
摘要:
In a magneto-optical recording medium comprising a recording layer and a reproducing layer, a transfer layer and a magnetic shielding layer are successively formed between the recording layer and the reproducing layer respectively. The reproducing layer is prepared from Gd33(Fe70Co30)67 changing from an in-plane magnetization film to a perpendicular magnetization film at 150° C., for example. The transfer layer is prepared from Gd28(Fe90Co10)72 changing from an in-plane magnetization film to a perpendicular magnetization film at 50° C., for example. The magnetic shielding layer is prepared from SiN, for example. The recording layer is prepared from Tb20(Fe90Co10)80 whose saturation magnetization is maximized around the transition temperature of 50° C. of the transfer layer. A signal can be directly recorded in the recording layer with no magnetic influence from the reproducing layer. A magnetic domain in the recording layer is transferred into the transfer layer by static magnetic interaction, and further transferred into the reproducing layer by exchange interaction. Thus, the signal can be stably reproduced in high density.
摘要:
In a magneto-optical recording medium comprising a recording layer and a reproducing layer, a transfer layer and a magnetic shielding layer are successively formed between the recording layer and the reproducing layer respectively. The reproducing layer is prepared from Gd33(Fe70Co30)67 changing from an in-plane magnetization film to a perpendicular magnetization film at 150° C., for example. The transfer layer is prepared from Gd28(Fe90Co10)72 changing from an in-plane magnetization film to a perpendicular magnetization film at 50° C., for example. The magnetic shielding layer is prepared from SiN, for example. The recording layer is prepared from Tb20(Fe90Co10)80 whose saturation magnetization is maximized around the transition temperature of 50° C. of the transfer layer. A signal can be directly recorded in the recording layer with no magnetic influence from the reproducing layer. A magnetic domain in the recording layer is transferred into the transfer layer by static magnetic interaction, and further transferred into the reproducing layer by exchange interaction. Thus, the signal can be stably reproduced in high density.
摘要:
A magneto-optical disk apparatus generates magnetic field onto a magneto-optical recording medium prior to recording signals in the magneto-optical recording medium having a recording layer and a reproduction layer, by use of magnetic field and laser beam. The magneto-optical apparatus then adjusts a position of a magnetic head that generates the magnetic field, under a state where the laser beam is irradiated, by utilizing that an irradiation spot of the laser beam deviates due to eccentricity of the magneto-optical recording medium. This position adjustment is carried out based on, for example, a beam position signal showing the irradiation spot of the laser beam and/or a detection signal which is detected after the laser beam is modulated by the magnetic field.