Abstract: A reading method for a magneto-optical recording medium is provided, irradiating laser light as a reading beam and using a magnetic head. High density and high transmission rate are possible and a correct reading can be performed according to the length of recording marks by reading the magneto-optical recording medium while impressing a magnetic field with an orientation promoting the translation of magnetic domain walls. In the magnetic super resolution type magneto-optical recording medium, which attains a signal only from one portion of the irradiation domain of the reading beam and has at least a recording layer and a reading layer on a substrate, the focused laser light is irradiated as a reading beam and the magnetic field is modulated, using the magnetic head, which is equipped with a slider and glides or floats on the recording medium.

Abstract: A reading method for a magneto-optical recording medium is provided, irradiating laser light as a reading beam and using a magnetic head. High density and high transmission rate are possible and a correct reading can be performed according to the length of recording marks by reading the magneto-optical recording medium while impressing a magnetic field with an orientation promoting the translation of magnetic domain walls. In the magnetic super resolution type magneto-optical recording medium, which attains a signal only from one portion of the irradiation domain of the reading beam and has at least a recording layer and a reading layer on a substrate, the focused laser light is irradiated as a reading beam and the magnetic field is modulated, using the magnetic head, which is equipped with a slider and glides or floats on the recording medium.

Abstract: A reading method for a magneto-optical recording medium is provided, irradiating laser light as a reading beam and using a magnetic head. High density and high transmission rate are possible and a correct reading can be performed according to the length of recording marks by reading the magneto-optical recording medium while impressing a magnetic field with an orientation promoting the translation of magnetic domain walls. In the magnetic super resolution type magneto-optical recording medium, which attains a signal only from one portion of the irradiation domain of the reading beam and has at least a recording layer and a reading layer on a substrate, the focused laser light is irradiated as a reading beam and the magnetic field is modulated, using the magnetic head, which is equipped with a slider and glides or floats on the recording medium.

Abstract: A reading method for a magneto-optical recording medium is provided, irradiating laser light as a reading beam and using a magnetic head. High density and high transmission rate are possible and a correct reading can be performed according to the length of recording marks by reading the magneto-optical recording medium while impressing a magnetic field with an orientation promoting the translation of magnetic domain walls. In the magnetic super resolution type magneto-optical recording medium, which attains a signal only from one portion of the irradiation domain of the reading beam and has at least a recording layer and a reading layer on a substrate, the focused laser light is irradiated as a reading beam and the magnetic field is modulated, using the magnetic head, which is equipped with a slider and glides or floats on the recording medium.

Abstract: An optical head includes: a light source; a photodetector for generating a prescribed signal based on light which the photodetector receives; a converging optical system for converging a light beam emitted from the light source to be incident upon a prescribed reflective member; and a reproducing optical system for guiding reflected light from the prescribed reflective member to the photodetector. The reproducing optical system is configured for converging light on a prescribed converging point, and a filter having a light transmissive region for allowing light in the vicinity of a center of the converged light to selectively pass therethrough is provided in the vicinity of the converging point. The light transmissive region of the filter is formed by light which has passed through at least a part of the reproducing optical system and has been converged.

Abstract: A read-only disk and a write-only disk recorded at high density having a magneto-optical film differing in coercive force depending on the information to be recorded disposed on a substrate. In the read-only and write-once disks, signals can be read employing only part of the irradiation beam, and thus super-resolution reading is realized.

Abstract: In a magneto-optical disc apparatus using an initializing magnetic field generator, the magnetic field generator including a permanent magnet slides on or and floats above a surface of the magneto-optical disc for applying a magnetic field at a position on a track and precede to or follow a light beam spot irradiated by an optical head.

Abstract: A magneto-optical recording medium includes at least a readout magnetic film and a recording magnetic film on a substrate, wherein information is recorded onto the recording magnetic film through magnetization of the recording magnetic film thereby forming domains therein, by a heating caused by irradiation of a recording light and application of a recording magnetic field, and the recorded information is read out through irradiation of a readout light thereby copying magnetization of the domains in the recording magnetic film to the readout magnetic film. The recording magnetic film is a perpendicular magnetic film in which the formed domains are retained The readout magnetic film Is a perpendicular magnetic film having a magnetic characteristic in which domains formed therein shrink The readout magnetic film contains no domains formed therein at a timing except for a readout operation to have a unidirectional magnetization.

Abstract: A read-only disk and a write-only disk recorded at high density having a magneto-optical film differing in coercive force depending on the information to be recorded disposed on a substrate. In the read-only and write-once disks, signals can be read employing only part of the irradiation beam, and thus super-resolution reading is realized.

Abstract: A reading method for a magneto-optical recording medium is provided, irradiating laser light as a reading beam and using a magnetic head. High density and high transmission rate are possible and a correct reading can be performed according to the length of recording marks by reading the magneto-optical recording medium while impressing a magnetic field with an orientation promoting the translation of magnetic domain walls. In the magnetic super resolution type magneto-optical recording medium, which attains a signal only from one portion of the irradiation domain of the reading beam and has at least a recording layer and a reading layer on a substrate, the focused laser light is irradiated as a reading beam and the magnetic field is modulated, using the magnetic head, which is equipped with a slider and glides or floats on the recording medium.

Abstract: In a magneto-optical recording medium for super resolution reproduction, a recording layer having a Curie temperature of 300.degree. C. or higher is used. An inhibition force for inhibiting movement of a domain wall in the recording layer is enhanced, while the magnetization is sufficiently increased such that a contraction force, which decreases a surface area of the domain wall, can be decreased. Thus, recording domains become stable during recording and erasing. Further, cross erasing characteristics can be improved, while maintaining previously used recording and erasing powers. The inhibition force becomes larger than the contraction force, even if the Curie temperature is low, when the recording layer is made of a first magnetic material for forming recording domains which have a compensation temperature between 0.degree. and 200.degree. C., or when the compensation temperature of the recording layer is between 0.degree. and 200.degree. C.

Abstract: A magneto-optical recording medium having a recording layer which has a first magnetic film, a second magnetic film and a third magnetic film in this order from a laser beam incident side, in which the second magnetic film has a perpendicular anisotropy in a temperature range from room temperature to a Curie temperature, the first magnetic film has an in-plane anisotropy when there is no temperature increase by the irradiation of a laser beam or a perpendicular anisotropy when the temperature is raised by the irradiation of the laser beam, and an exchange coupled force is present between the first magnetic film and the second magnetic film.

Abstract: In one embodiment, the magneto-optical recording medium of the present invention has a recording layer structure including at least a readout magnetic film, a control magnetic film, and a recording magnetic film. The readout magnetic film is a perpendicular magneto-anisotropy film at a temperature in a predetermined range. The control magnetic film provided between the readout magnetic film and the recording magnetic film has a prescribed structure so as to assume a perpendicular magneto-anisotropy film at a temperature in a predetermined range and an in-plane magneto-anisotropy film at a temperature in a range other than the predetermined range.

Abstract: A disk drive apparatus is provided that can reproduce data at low bit error rate even if a crosstalk is large. This apparatus comprises means for writing three or more different states of record marks in a read track and adjacent tracks thereof on a disk storage medium, means for detecting read levels of the record marks in the read track, means for calculating every possible read level regarding every possible combination of the record marks in the read track and adjacent tracks thereof according to the detected read levels, and means for performing most-liklihood decoding of written data in accordance with the possible read levels as reference levels.

Abstract: A magneto-optical recording medium includes at least a reading layer and a writing layer on a substrate. A track guide groove is formed in the medium so as to include in-groove portions and on-land portions. Only a portion where a temperature has been raised by optical beam irradiation is read, while a domain of a writing layer is copied on the writing layer, whereby a writing/reading operation can be effected with narrower track pitches. By this arrangement, there can be realized a narrow track pitch which is narrower than the diameter of a laser beam.

Abstract: In a magneto-optical recording medium for super resolution reproduction, a recording layer having a Curie temperature of 300.degree. C. or higher is used. An inhibition force for inhibiting movement of a domain wall in the recording layer is enhanced, while the magnetization is sufficiently increased such that a contraction force, which decreases a surface area of the domain wall, can be decreased. Thus, recording domains become stable during recording and erasing. Further, cross erasing characteristics can be improved, while maintaining previously used recording and erasing powers. The inhibition force becomes larger than the contraction force, even if the Curie temperature is low, when the recording layer is made of a first magnetic material for forming recording domains which have a compensation temperature between 0.degree. and 200.degree. C., or when the compensation temperature of the recording layer is between 0.degree. and 200.degree. C.

Abstract: An optical disk formation member has a center and an outer periphery. A tracking guide groove formation portion and a prepit formation portion are provided on the member. A first land plane on an internal peripheral side of the prepit formation has a depth that is different from a second land plane on the external peripheral side of the prepit formation portion. The second land plane, furthermore, is deeper than the first land plane on the internal peripheral side of the prepit formation portion.

Abstract: An optical recording medium for recording, reading, erasing information with beams has a layer composed of a lower thermal conductivity material and a heat sink layer of a higher thermal conductivity material sequentially laminated on a reading and reading layer composed of at lest a recording thin film and a reading thin film. Therefore, an optical recording medium can be realized where the range of the recording power to be tolerated even in a case of a disk smaller in track pitch and the movement of the central position of the temperature distribution is small, namely, an optical recording medium where the recording power margin is large and the high density recording operation can be effected.

Abstract: A method of making a stamper uses a photoresist disk cut by the application of a laser beam on the land planes thereof, or a stamper which is different in depth between the land plane on the internal peripheral side with respect to the prepit portion and the land plane on the external peripheral side. A method of making an optical disk substrate includes the steps of using a stamper, and molding a transparent plastic material with an injection molding method. A stamper capable of sufficiently transferring the prepits and guide grooves on the optical disk substrate with the correction of right and left inequality of the prepits, and the method of making it, and a superior optical disk substrate and a method of making it can be realized.

Abstract: A magneto-optical recording medium includes a magneto-optical layer, a reflection layer and an inorganic dielectric layer interposed therebetween. The dielectric layer is extremely thin so that it will exhibit almost no optical effect, thereby allowing a high CN ratio to be obtained. Thermal conductivity of the dielectric layer is so low that the magneto-optical and reflection layers are thermally isolated from each other. That is, if refractive index of the dielectric layer is n, thickness of the dielectric layer is T (nm), and the thermal conductivity of the dielectric layer is C (J (m sec K).sup.-1), then the thickness T is set within a range that satisfies the following equation:5n-4.ltoreq.T.ltoreq.(12n-4)(C/2.1).sup.-0.4where C.ltoreq.4J (m sec K).sup.-1.