Abstract: On a pit information surface (22d) of a read-only optical disk (22), a protective layer (22f) suited for a floating-type or a sliding-type magnetic head (3) used for a magnetic field modulation type magneto-optical disk is formed. A reproducing operation with respect to the optical disk (22) is performed while allowing the magnetic head (3) to slide on the protective layer (22f). Accordingly, a magnetic head does not need to be separated from a disk in reproduction. Thus, an optical disk device can be manufactured at lower cost and reduced in size, and a high-speed seek can be realized. Commonality of a disk cartridge (32) with the magnetic field modulation type magneto-optical disk also can be achieved. An optical disk system that is user-friendly thus can be obtained.

Abstract: A data recording medium has tracks with pseudo-noise (PN) sequences with good autocorrelation properties as servo information for controlling the position of the recording head. A first set of alternating tracks uses a leading pseudo-random binary sequence (PRBS), which is a PN sequence with good autocorrelation properties, and a following PRBS that is cyclically shifted from the leading PRBS. A second set of alternating tracks interleaved with the first set also has a leading PRBS and a following PRBS that is cyclically shifted from the leading PRBS, but the leading PRBS in each of the tracks in the second set is offset along-the-track from the leading PRBS in the tracks of the first set. The head positioning control system uses the leading PRBS to generate a servo timing mark (STM), the cyclic shift to generate track identification (TID), and the following PRBS from adjacent tracks to generate the head position error signal (PES).

Abstract: A disc drive to control a home-in mode and method thereof includes a pickup unit irradiating a light beam on a disc loaded in the disc drive, a motor moving the pickup unit along a radius direction of the disc, and a control unit detecting and storing position information of the pickup unit based on driving pulses of the motor. The control unit controls a generation of the driving pulses of the motor using information of a home-in position based on the stored position information of the pickup unit and the driving pulses of the motor.

Abstract: When carrying out magnetization, annealing, and initialization of a recording film by applying a laser beam to the recording film while rotating an optical recording medium 10 by a motor 11, light of a strong visible-light lamp 15 is projected as parallel light to a reflecting mirror 14 via a lens 16 so as to apply light reflected by the reflecting mirror 14 to an area wider than a spot of the laser beam on the medium 10 for heating. At that time, a control unit 18 controls an intensity of the strong visible-light lamp 15 to raise a temperature of the medium 10 to a temperature of 80° C. or higher and a softening point of a substrate or lower, for example.

Abstract: The present invention is a method of reading and writing in MAMMOS that uses the edge of the thermal profile for detection of a domain rather than using the tip of the profile. By using the edge, it is possible to detect the position of domains rather than merely the presence of domains. Thus, domain positions are used to store data. By measuring these positions relative to the last domain, more accuracy can be gained. The new scheme is called Domain Position Detection for MAMMOS (DPD-MAMMOS). In DPD-MAMMOS, the information is encoded into the MAMMOS media in the form of the position of the domains rather than the presence of the domains. In this way, each domain stored in the media can contain several bits or possibly bytes of information. Methods of reading and writing information are disclosed.

Abstract: The present invention proposes a method of controlling the laser power of a semiconductor laser that, in this method of controlling the laser power of a semiconductor laser by applying a power source voltage to between the collector and emitter of an output transistor and a serial circuit of the output transistor and a semiconductor laser, enables decreasing the power consumption of the output transistor. The present invention is arranged to apply a variable power source voltage Vcc to a serial circuit of an output transistor (Qb) and a semiconductor laser (SL) and thereby control the variable power source voltage Vcc such that a difference between the variable power source voltage Vcc and the peak hold voltage of an operating voltage of the semiconductor laser (SL) becomes substantially constant.

Abstract: An optical disc includes an information recording layer having a record of information as a pit train with a predetermined track pitch and a light-transmissive layer formed on the information recording layer so that the information can be reproduced by a beam of light illuminated through the light-transmissive layer to the information recording layer by an objective lens. The optical disc includes a feature in that a relationship of 0.194(?/NA)2?TP ×Tmin?0.264(?/NA)2 is satisfied, provided that the track pitch is TP, a pit shortest length is Tmin, a wavelength of the light beam is ? and a numerical aperture of the objective lens is NA. The optical disc also includes a feature in that a pit width is 120 nm or smaller in a range of a track pitch of 0.280 to 0.325 ?m.

Abstract: An information reproducing/recording system has a reproducing apparatus which reproduces program information from a first recording medium, a recording/reproducing apparatus which records program information on a second recording medium or reproduces program information from the second recording medium, and a control apparatus which controls the reproducing apparatus and the recording/reproducing apparatus. The control apparatus acquires first management information for program information recorded on the first recording medium, and acquires second management information for program information recorded on the second recording medium. And then, the control apparatus compares the first management information and the second management information, and judges based on the result of comparison whether program information corresponding to the first management information has been recorded on the second recording medium.

Abstract: Management information is read from an information storage medium having the management information recorded thereon, the management information including track number information imparted to at least one track and group management information for managing as selective recording information one or a plurality of tracks as one group. Judgment is then made upon whether the group management information is included in that management information. A display mode is changed depending on a case where the group management information is recorded and a case where it is not recorded, and it is then displayed in a displaying device.

Abstract: The present invention is directed to a drive device comprising an electromechanical transducer (25) attached to one end of a drive shaft (24) and adapted to be expanded and contracted in the axial direction of the drive shaft (24) in accordance with drive voltage to thereby allow the drive shaft (24) to undergo displacement in the axial direction thereof, and an optical pick-up (14) movably supported in the axial direction of the drive shaft (24) and moved along the drive shaft (24) as the result of the fact that the drive shaft (24) is caused to undergo displacement by the electromechanical transducer (25) to apply a drive voltage higher than that at the time of steady transfer to the electromechanical transducer (25) at the time of starting.

Abstract: A first storage device control device stores, when a first data write/read request is received, correspondences between first logical units and second logical units referenced when determining whether or not storage regions identified by first logical units set in the request are storage regions of the first logical device control device or storage regions of a second storage device control device, the second storage device control device transmits all or some of identification information (logical unit information) of the second logical units to a management computer, the first storage device control device transmits all or some of the correspondences (mapping information) to the management computer, and the management computer references the received logical unit information and the mapping information to generate information representing whether or not the second logical units are corresponded to the first logical units.

Abstract: It is an object of the present invention to provide a magneto-optical recording medium including a recording film having at least a reproduction layer, an intermediate layer, and a recording layer, on an optical disk substrate, wherein the recording film is a magnetic film that is magnetically coupled and that has magnetic anisotropy in a direction vertical to its film surface, the recording magnetic domains formed in the recording layer are transferred to the reproduction layer, and recording information is reproduced by domain wall movement in the reproduction layer, and the recording layer has columnar structures that are oriented substantially vertically.

Abstract: An apparatus for holding digital data. The apparatus includes a medium in which a plurality of dimples are spaced for tracking by a playing apparatus. Each dimple includes a plurality of facets, and each facet represents a data bit. Because the location of each dimple is predetermined, a tracking assembly can use the dimple locations for tracking purposes. Thus there is no need to reserve bits for tracking purposes, and more data can be stored in a given space on a given medium than with previously developed high-density digital storage media.

Abstract: An optical pickup apparatus used in an optical data recording/reproducing apparatus for reading/reproducing data on an optical recording medium, including a light source, a diffracting device configured to transmit a light beam and to diffract a light beam reflected from the optical recording medium, an optical device having a reflecting portion and a transmitting portion configured to reflect one part of the light beam emitted from the light source and to transmit another part of the light beam to the optical recording medium and from the optical recording medium, and a photodetecting device to detect the light beam from the optical recording medium for signal light detection, and the light beam reflected by the reflecting portion of the optical device for monitor light detection of the light source.

Abstract: A recording medium comprises pairs of groove tracks and land tracks provided side by side while being bent periodically, a plurality of land prepits previously formed on the land tracks and carrying information about the groove tracks, and a recording layer formed on at least the groove tracks and the land tracks. The land prepits have a radius of mean curvature smaller than a radius of mean curvature of sides of the groove tracks in land-prepit absent regions of the land prepits and are defined by curved surfaces continuously extending from the sides of the groove tracks. Those sides of the groove tracks which face the continuous curved surfaces of the land prepits are curved surfaces that stricture the groove tracks.

Abstract: An information recording medium is at least composed of a substrate having a microscopic pattern constituted by a continuous substrate of grooves formed with a groove portion and a land portion alternately, a recording layer formed on the microscopic pattern for recording information, and a light transmitting layer formed on the recording layer. The microscopic pattern is formed with satisfying a relation of P??/NA, wherein P is a pitch of the land portion or the groove portion, ? is a wavelength of reproducing light for reproducing the recording layer, and NA is a numerical aperture of an objective lens. The land portion is formed with wobbling so as to be parallel with each other for both sidewalls of the land portion. An auxiliary information based on data used supplementally when recording the information and a reference clock based on a clock used for controlling a recording speed when recording the information is recorded alternately.

Abstract: A method is disclosed for jumping tracks on a double-layer optical disk from a first address A on a first data layer to a target address D on a second data layer. According to the method, the first address A where the optical head is currently positioned is read. Then, after jumping to the second data layer, a relative second address B on the second data layer that corresponds to the first address A on the first data layer is read. If the second address B on the second data layer is smaller than the first address A on the first data layer, then the address of the second address B on the second data layer is shifted and a new target address is obtained on the second data layer based on this address shift. A calculation function is performed based on the first address A and the new target address, and then the optical head is moved to the new target address on the second data layer.

Abstract: An optical pickup apparatus for reproducing information from an optical information recording medium or for recording information onto an optical information recording medium, is provided with a first light source for emitting first light flux having a first wavelength; a second light source for emitting second light flux having a second wavelength, the first wavelength being different from the second wavelength; a converging optical system having an optical axis and a diffractive portion, and a photo detector; wherein in case that the first light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the first light flux is greater than that of any other ordered diffracted ray of the first light flux, and in case that the second light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the second light flux is greater than that of any other ordered diffracted

Abstract: A high-density data storage medium, a method of manufacturing the data storage medium, a high-density data storage apparatus, and methods of writing data on, and reading and erasing data from the data storage medium by using the data storage apparatus are provided. The data storage medium includes a lower electrode, an insulation layer deposited on the lower electrode, a photoelectron emission layer deposited on the insulation layer and having a plurality of protrusions from which photoelectrons are emitted due to collisions between the protrusions and photons, and a dielectric layer deposited on the photoelectron emission layer and storing the photoelectrons emitted from the photoelectron emission layer.

Abstract: This invention comprises a two part audio system in which all of the processing power is allocated to a small, lightweight satellite part that is the face unit. Mass storage, amplification, and wired power for recharging the face unit is provided by the other part, the base. The base runs either from a 120 volts AC source or 12 volts DC. The face unit contains a small amount of flash memory making it capable of carrying music normally stored on two or more compact discs (CDS).