Abstract: A method of recording data on a disc on a disc pre-recorded with servo control data, with the servo control data being pre-recorded in the form of convex and concave pits at intervals along substantially concentric tracks, the servo control data recorded in alignment in a diametrical direction of the disc. The method includes the steps of dividing the disc into a plurality of zones in the radial direction, dividing the tracks into a plurality segments such that there is an equal number of segments in each interval between adjacent pre-recorded servo control data. The method further includes the step of recording reference data on at least one segment of the plurality of segments in each interval between adjacent servo control data, with the reference data being utilized to adjust a gain and a phase of a read-out clock upon reproduction of the disc.

Abstract: A magneto-optical disc system includes a magneto-optical disc 40 with a light-transmitting cover layer 41, an objective lens 2 for bundling or focusing a laser beam onto a magnetic recording layer 43 of the magneto-optical disc 40 for recording information thereon and/or reproducing information therefrom, and a magnetic field generating unit 9 having a coil pattern 7 arranged on an optical glass element 8. The thickness t.sub.2 of the light-transmitting cover layer 41 falls within the range of 0.6 to 0.1 mm, and the numerical aperture (NA) of the objective lens 2 falls within the range of 0.55 to 0.70.

Abstract: A disc recording and/or reproducing apparatus including a signal recording/reproducing section for recording and/or reproducing information signals on a disc 64 mm in diameter housed in a cartridge main body to form a disc cartridge, a loading mechanism for loading or unloading the disc cartridge on or from the signal recording/reproducing section and a control circuit controlling the recording/reproducing operation of the recording/reproducing section. The disc has a signal recording part divided into plural signal recording zones of substantially equal line recording density across the inner and the outer peripheries of the disc. The signal recording/reproducing section, the loading mechanism and the control circuit are housed in a casing which is 70 mm or less in width, 100 mm or less in length and 24.5 mm or less in height and which is provided with a disc inserting opening. The apparatus may be reduced in size without decreasing the recording capacity.

Abstract: A disc recording and/or reproducing apparatus including a signal recording/reproducing section for recording and/or reproducing information signals on a disc 86 mm in diameter housed in a cartridge main body to form a disc cartridge, a loading mechanism for loading or unloading the disc cartridge on or from the signal recording/reproducing section and a control circuit controlling the recording/reproducing operation of the recording/reproducing section. The disc has a signal recording part divided into plural signal recording zones of substantially equal line recording density across the inner and the outer peripheries of the disc. The signal recording/reproducing section, the loading mechanism and the control circuit are housed in a casing which is 101.6 mm or less in width, 150 mm or less in length and 25.4 mm or less in height and which is provided with a disc inserting opening. The apparatus may be reduced in size without decreasing the recording capacity.

Abstract: An magneto-optical disc system includes an magneto-optical disc with a light-transmitting cover and an objective lens for bundling or focusing a laser beam on a recording layer of the magneto-optical disc in order to perform recording and/or reproduction. The thickness t.sub.2 of the light-transmitting cover is set to fall within the range of 0.6 to 0.1 mm, the numerical aperture (NA) of the objective lens is set to fall within the range of 0.55 to 0.70 and the wavelength of the light beam is selected to be between 635 and 680 nanometers.

Abstract: An optical disc system using an optical disc with a light-transmitting cover and an objective lens for bundling or focusing a laser beam on a recording layer of the optical disc in order to perform recording and/or reproduction. The thickness t.sub.2 of the light-transmitting cover is set to fall within the range of 0.6 to 0.1 mm, the numerical aperture (NA) of the objective lens is set to fall within the range of 0.55 to 0.70 and the wavelength of the light beam is selected to be between 635 and 650 nanometers.

Abstract: In a disc recording method in which a disc on which servo control data is recorded in advance in alignment with a radial direction is divided into a plurality of zones in the radial direction and digital data having different clock rates are recorded on every zone, reference data for detecting the quality of a recording signal is recorded on a whole recording data area of one segment segmented by at least said servo control data. Therefore, the reproduction of data recorded in the zone-recording fashion can be controlled with ease in any zone.

Abstract: An optical disc system using an optical disc with a light-transmitting cover and an objective lens for bundling or focusing a laser beam on a recording layer of the optical disc in order to perform recording and/or reproduction. The thickness t.sub.2 of the light-transmitting cover is set to fall within the range of 0.6 to 0.1 mm, the numerical aperture (NA) of the objective lens is set to fall within the range of 0.55 to 0.70 and the wavelength of the light beam is selected to be between 635 and 650 nanometers.

Abstract: An apparatus reproducing signals recorded on an optical disc rotated at a constant angular velocity. The apparatus employs a binary detector for forming digital data by comparing the reproduced signal with a predetermined threshold level, and a ternary detector for forming reproduced data from two series of digital data detected by comparing the reproduced signal with two different threshold levels of predetermined values. The reproduced data from an outer portion of the disc is detected by the binary detector, while the reproduced data from an inner portion of the disc is detected by the ternary detector. The playback output is selectively switched in response to an address signal of a specific track where the phase margin of the reproduced data detected by the binary detector and the phase margin of the reproduced data detected by the ternary detector becomes substantially equal to each other.

Abstract: A magneto-optical disc system includes a magneto-optical disc with a light-transmitting cover, an objective lens for bundling or focusing a laser beam on a magnetic recording layer of the magneto-optical disc in order to perform recording and/or reproduction, and a magnetic field generating unit obtained by forming a coil pattern in an optical glass. In the above system, the thickness t.sub.2 of the light-transmitting cover is set to fall within the range of 0.6 to 0.1 mm, and the numerical aperture (NA) of the objective lens is set to fall within the range of 0.55 to 0.70, so as to obtain high-density recording and/or reproduction by permitting the lens to be quite close to the actual recording layer.

Abstract: A is a magneto-optical disc system includes a magneto-optical disc with a light-transmitting cover, an objective lens for bundling or focusing a laser beam on a magnetic recording layer of the magneto-optical disc in order to perform recording and/or reproduction, and a magnetic field generating unit obtained by forming a coil pattern in an optical glass. In the above system, the thickness t.sub.2 of the light-transmitting cover is set to fall within the range of 0.6 to 0.1 mm, and the numerical aperture (NA) of the objective lens is set to fall within the range of 0.55 to 0.70, so as to obtain high-density recording and/or reproduction by permitting the lens to be quite close to the actual recording layer.

Abstract: A magneto-optical disc system includes a magneto-optical disc with a light-transmitting cover, an objective lens for bundling or focusing a laser beam on a magnetic recording layer of the magneto-optical disc in order to perform recording and/or reproduction, and a magnetic field generating unit obtained by forming a coil pattern in an optical glass. In the above system, the thickness t.sub.2 of the light-transmitting cover is set to fall within the range of 0.6 to 0.1 mm, and the numerical aperture (NA) of the objective lens is set to fall within the range of 0.55 to 0.70, so as to obtain high-density recording and/or reproduction by permitting the lens to be quite close to the actual recording layer.

Abstract: A magneto-optical disc recording apparatus includes a magnetic head, an optical head, a position detector and a controller. The magnetic head supplies a vertical magnetic field corresponding to recording data to a magneto-optical disc. The optical head emits a light beam to the magneto-optical disc through a substrate of the magneto-optical disc. The magneto-optical disc is arranged between the magnetic head and the optical head. The optical head has an actuator for moving an objective lens in a tracking direction. The position detector detects the displacement of the actuator. The controller controls a recording operation of the magnetic head and the optical head. The recording operation is started when a result of detection by the position detector reaches a predetermined value.

Abstract: A magneto-optical recording and reproducing system in a magneto-optical disk capable of being overwrite recorded by applying a magnetic field to a photo-sensitive recording layer and irradiating a laser beam onto the recording layer. A track pitch and a diameter of the laser beam are set so that recording tracks to be formed by irradiation of the laser beam overlap, each other between adjacent tracks. Accordingly, data recording density of the magneto-optical disk, especially in a radial direction thereof, can be increased.

Abstract: A magneto-optical disc recording/reproducing apparatus in which a magneto-optical disc, a disc rotating and driving unit, an optical head device, an external magnetic field generating unit and a controlling device are contained as one in an outer casing.

Abstract: A disc recording and/or reproducing apparatus including a signal recording/reproducing section for recording and/or reproducing information signals on a disc 86 mm in diameter housed in a cartridge main body to form a disc cartridge, a loading mechanism for loading or unloading the disc cartridge on or from the signal recording/reproducing section and a control circuit controlling the recording/reproducing operation of the recording/reproducing section. The disc has a signal recording part divided into plural signal recording zones of substantially equal line recording density ac ross the inner and the outer peripheries of the disc. The signal recording/reproducing section, the loading mechanism and the control circuit are housed in a casing which is 101.6 mm or less in width, 150 mm or less in length and 25.4 mm or less in height and which is provided with a disc inserting opening. The apparatus may be reduced in size without decreasing the recording capacity.

Abstract: A magneto-optical disc system includes a magneto-optical disc with a light transmitting protective layer, an objective lens for bundling or focusing a laser beam onto a magnetic recording layer of the magneto-optical disc in order to perform recording and/or reproduction, and a magnetic field generating unit formed as a coil pattern on a transparent optical glass layer. In the magneto-optical disc system, the thickness t.sub.2 of the light-transmitting protective layer is set to fall within the range of 0.6 to 1.0 mm and the numerical aperture of the objective lens is set to fall within the range of 0.55 to 0.70, so as to obtain high density recording and/or reproduction by permitting the lens to be quite close to the actual recording layer.

Abstract: A magneto-optical disc recording/reproducing apparatus in which a magneto-optical disc, a disc rotating and driving unit, an optical head device, an external magnetic field generating unit and a controlling device are contained as one in an outer casing.

Abstract: A magneto-optical pickup apparatus includes an objective lens for focusing a laser beam emitted from a laser device onto a magneto-optical recording medium, driving coils, on which the objective lens is mounted, for driving the objective lens in focusing and tracking directions, and a plate arranged at an end portion of the driving coils between the objective lens and the magneto-optical recording medium. The plate is formed with a coil pattern for generating a magnetic field to be applied to the magneto-optical recording medium, and can allow a laser beam transmitted through the objective lens to pass therethrough.

Abstract: In a recording apparatus employing a magneto-optical effect, and in which a light beam irradiates a region of a magneto-optical disc while a magnetic field acts on the disc at such region and is modulated by coded data in accordance with a predetermined modulation system; the light beam is intermittently energized by drive pulses, and the energizing of the light beam is inhibited at times corresponding to transitions in the coded data when the ratio Tmin/Tw is greater than 1, in which Tmin is the minimum length between transitions in the coded data and Tw is a window margin for the modulation system employed for modulating the magnetic field.