Abstract: A small-sized, large-capacity optical disk is provided which is superior in portability. The optical disk has a diameter less than 64 mm and a thickness less than 0.8 mm. Tracks are formed with a pitch less than 0.6 ?m, and the record area is divided into a plurality of zones alone the radium. The optical disk can store more than 650 MB of compressed data.

Abstract: An object of the present invention is to provide a lapping machine in which abrasive grains can be efficiently and completely removed from a lapping plate. In the lapping machine of the present invention, a lapping plate has a lapping face and rotates about a rotary shaft. A moving member has a wiping face extended in a longitudinal and moves, in a plane parallel to the lapping face of the lapping plate, in the direction perpendicular to the wiping face. A driving mechanism moves the moving member. With this structure, the moving member securely catches and removes foreign substances from the lapping plate. The foreign substances left can be completely removed in a short time and the working efficiency of the lapping steps can be highly improved.

Abstract: An object of the present invention is to provide a lapping machine in which abrasive grains can be efficiently and completely removed from a lapping plate. In the lapping machine of the present invention, a lapping plate has a lapping face and rotates about a rotary shaft. A moving member has a wiping face extended in a longitudinal and moves, in a plane parallel to the lapping face of the lapping plate, in the direction perpendicular to the wiping face. A driving mechanism moves the moving member. With this structure, the moving member securely catches and removes foreign substances from the lapping plate. The foreign substances left can be completely removed in a short time and the working efficiency of the lapping steps can be highly improved.

Abstract: A method of manufacturing a magnetic head slider from a flying surface pattern formed on one surface of a long and slender rectangular parallelepiped slider block having a plurality of thin film magnetic head elements aligned in a row. The method includes preparing an arrangement jig including a guide plate and an adhesive rubber plate which adheres onto a lower surface of the guide plate by its adhesive force. The method also includes placing blocks in the accommodation holes on the guide plate in such a manner that the surface of each block on which a pattern is formed is directed upward and each block is fixed by the adhesive force of the rubber plate. The rubber plate is then peeled off after an upper surface of the arrangement jig has been set upside down. Pouring and penetrating hardening liquid into clearances formed between the accommodation holes on the guide plate and the blocks is the next step. The guide plate is then fixed onto a base plate and a pattern is formed on the surface of each block.

Abstract: Grooves and lands are provided to a magneto-optical disk so as to be alternately arranged, and recording bit strings are formed on the grooves and lands respectively so that information is recorded. Moreover, pit rows are formed on boundary sections between the adjoining grooves and lands so that address information of a recording/reproducing track is recorded, and the pit rows are formed every other boundary section. When the grooves and the lands are scanned as the recording/reproducing track by a light, an address of the recording/reproducing track is read out from the pit rows, and successively, discrimination is made whether the recording/reproducing track which is scanned by an optical spot is the groove or the land. This prevents crosstalk which causes inclusion of address information in the next pit rows, thereby, making it possible to obtain accurate address information.

Abstract: A magneto-optical disk including a transparent substrate, pit strings containing information formed in spiral or concentric form on a surface of the transparent substrate, a magneto-optical recording medium layer for covering the surface of the transparent substrate having the pit strings formed thereon, and magneto-optical recording areas formed by spiral or concentric flat portions between adjacent pit strings. An optical pickup for reproducing pit information and magneto-optically-recorded information from the magneto-optical disk. A magneto-optical disk drive for recording and reproducing information on the magneto-optical disk. The magneto-optical disk has a memory capacity which is twice the memory capacity of a conventional magneto-optical disk having ROM, and is accessed at high speeds.

Abstract: A magneto-optical disk including a transparent substrate, pit strings containing information formed in spiral or concentric form on a surface of the transparent substrate, a magneto-optical recording medium layer for covering the surface of the transparent substrate having the pit strings formed thereon, and magneto-optical recording areas formed by spiral or concentric flat portions between adjacent pit strings. An optical pickup for reproducing pit information and magneto-optically-recorded information from the magneto-optical disk. A magneto-optical disk drive for recording and reproducing information on the magneto-optical disk. The magneto-optical disk has a memory capacity which is twice the memory capacity of a conventional magneto-optical disk having ROM, and is accessed at high speeds.

Abstract: A magneto-optical recording device includes a magnetic field generating coil for generating a magnetic field on a magneto-optical recording medium, a power source for supplying a current to the magnetic field generating coil, switching circuit for driving said magnetic field generating coil to supply the current from the power source in the positive and negative directions by alternately forming first and second current paths according to recording information, first correcting circuit which is disposed on the first current path for correcting a transient response of the current amplitude in the positive direction caused by the magnetic field generating coil, and second correcting circuit which is provided on the second current path for correcting a transient response of the current amplitude in the negative direction caused by the magnetic field generating coil.

Abstract: Grooves and lands are provided to a magneto-optical disk so as to be alternately arranged, and recording bit strings are formed on the grooves and lands respectively so that information is recorded. Moreover, pit rows are formed on boundary sections between the adjoining grooves and lands so that address information of a recording/reproducing track is recorded, and the pit rows are formed every other boundary section. When the grooves and the lands are scanned as the recording/reproducing track by a light, an address of the recording/reproducing track is read out from the pit rows, and successively, discrimination is made whether the recording/reproducing track which is scanned by an optical spot is the groove or the land. This prevents crosstalk which causes inclusion of address information in the next pit rows, thereby, making it possible to obtain accurate address information.

Abstract: A magnetic head unit is provided by which damage to a conductive-pattern layer formed on a spring arm during a bending process of the spring arm can be prevented. The magnetic head unit comprises a magnetic head and a spring arm having a bent portion which is bent to generate an elastic force. The magnetic head is mounted on an end of the spring arm. At least one conductive-pattern layer is formed on a surface of the spring arm to extend from a gimbal portion where the magnetic head is mounted to a attachment portion where the spring arm is mounted to a member of a magnetic head driving mechanism. The bent portion has a first portion and a second portion separated from the first portion. The conductive-pattern layer passes through the second portion. No external force is applied to the conductive-pattern layer formed during a bending process for the bent portion.

Abstract: The present invention is provided with a disturbance observer which outputs a compensating signal for compensating a driving signal of a linear motor in accordance with (1) an output signal of an acceleration sensor unit which mechanically detects an acceleration of the linear motor, the acceleration moving the optical pickup, and (2) the driving signal of the linear motor. A high pass filter which has a low frequency band cutoff frequency substantially same as that of the acceleration sensor unit is also provided on the path which is formed by connecting the input of the driving signal to the generated compensating signal in the disturbance observer. With the high pass filter, it is possible to prevent the linear motor from being driven too sensitively or too greatly by the disturbance observer due to the driving signal, vibrations, or shocks applied from outside, or noises from the acceleration sensor unit or the circuits, thereby avoiding the danger that the linear motor or the optical pickup is damaged.

Abstract: In an information regenerating apparatus, recorded data constructed of a sector mark and a following header section having a plurality of data sets each having a pull-in pattern, an address mark and address information, is read out to form a regenerative signal which in turn is used to regenerate information. A phase-locked loop circuit in a signal synchronizing circuit, performs phase-synchronization with a regenerative signal at two different pull-in speeds. A speed indicating circuit, based on the counting of the number of clock pulses from a reference clock signal from a time of the generation of a sector mark detection signal showing the detection of the sector mark as a reference point, instructs the phase-locked loop circuit to set up a fast response speed every time the pull-in pattern appears on the regenerative signal, and instructs the phase-locked loop circuit to set up a slow response speed every time the pull-in pattern disappears from the regenerative signal.

Abstract: A magneto-optical memory apparatus for enhancing the recording density of a magneto-optical recording medium, thereby to increase its recording capacity. The magneto-optical recording medium having recording marks, each having two ends in which information is recorded.

Abstract: An information recording and reproducing device uses a recording medium which is provided with units composed of blocks and a unit information recording area which includes unit allocation information, sector number information indicating the number of sectors per unit and unit number information identifying each unit. When the recording medium is placed in the device, the respective information is read by a calculating unit which calculates physical sector numbers corresponding to a block specified for recording and reproduction operations. Access operations are performed to the calculated sectors, which allows the desired information to be recorded. The block includes dummy sectors which are added before and after each group of predetermined numbers of effective sectors. When high-volume information is recorded over several blocks, the dummy sectors may be provided only for the first and last blocks.

Abstract: A recording and reproducing device, which records and reproduces information on and from a rewritable recording medium having absolute addresses and including an information recording area wherein information entered from external devices is recorded and a Table of Contents area wherein additional address information with respect to the information recorded in the information recording area is recorded. The TOC area contains the absolute addresses of the recording positions of each information recorded in the information recording area. A display section graphically and independently displays the recorded and unrecorded ranges of the information recording area according to the absolute addresses recorded in the TOC area with respect to the recording positions of each piece of information.

Abstract: A disk recording and reproducing device records and reproduces information on and from a magneto-optical disk having 3 3 and there is TOC (Table of Contents) area. Additional information with respect to each piece of the information recorded in the information recording area is recorded in the TOC. The device includes operation keys, a TOC memory for storing read/write control information for desired pieces of information entered through the operation keys. There is an optical head and a magnetic coil for recording, in the TOC area, the contents stored in the TOC memory as additional information. A controller controls the read/write operation to the disk according to the read/write control information. With the arrangement, a user can recognize necessary/unnecessary information and defective parts in the disk, and therefore make effective use thereof as well as maintaining secrecy of the information.

Abstract: A recording/reproducing device for recording and reproducing on a rewritable recording medium which comprises absolute addresses, a sound information recording region for recording sound information entered thereto from outside and a TOC area for recording additional information on the sound information recorded in the sound information recording region.

Abstract: An information recording and reproducing device having an automatic gain control device wherein its amplification degree is adjusted according to an AGC voltage varying with an amplitude of a reproduced signal. The automatic gain control device has a holding circuit which holds the AGC voltage in each of recording and erasing operations, and also holds the AGC voltage in reproducing an un-recorded area of information. The AGC voltage is also used for determining an optimum recording condition for a recording medium. Instead of the holding circuit, by installing a limiter circuit for limiting an amplitude of a reproduced signal, and by the use of transient response of the reproduced signal due to an coupling situated before the limiter circuit, an appropriate amplification degree can also be obtained in the automatic gain control device.

Abstract: In the optical recording element of the invention, alignments of long thin pits inclined in various directions with respect to the track direction are formed on the tracks and information is recorded therein according to the different inclines of the pits, thereby performing higher-density and larger-volume recording without reducing the spacing between each pit and the track pitch. The invention also discloses an optical data retrieval system for use with the above optical recording element, which scans the pit alignments with a laser beam spot, detects the inclines of the pits by obtaining the distribution of the intensity of reflected light which is caused by light diffraction at the pits, and plays back information in accordance with the inclines. Therefore, not only can the substantially same structure as that of a standard type optical data retrieval system be applied to the invention without making any complicated change, but also cross-talk is less likely to be produced in the read out signals.

Abstract: An information recording and reproducing device has a first recording clock generation circuit which generates a clock based on pre-recorded information on a magneto-optical disk, a second recording clock generation circuit and a switching circuit The switching circuit selects a first recording clock when recording information is of discrete information and selects a second recording clock when recording information is of successive information. Moreover, in the present device, a first reading clock is used as well as a second clock as a clock for reading out the reproduced data from the magneto-optical disk, which had been once stored in memory. The second reading clock having a reference frequency is generated by a second clock generation circuit and is used for reading out successive information such as music information.