Abstract: An information recording medium of this invention comprises a plurality of concentric tracks or a spiral track, having a plurality of recording tracks for recording information, and record pits formed on the recording tracks, said record pits being formed at a predetermined pitch on an innermost recording track, and said record pits being formed in accordance with movement of a position of a target recording track from the innermost track toward an outermost track, while gradually increasing the predetermined pitch at a rate less than that at which linear velocity increases when said information recording medium is rotated at a constant velocity.

Abstract: A magneto-optical data reading member includes a transparent disk substrate, and land-shaped areas formed on the disk substrate in a spiral manner so as to be parallel with each other, and groove-shaped areas formed to be stepped with respect to the land-shaped areas, wherein each of the land-shaped and groove-shaped areas has, in a surface region thereof, a first magnetic film for reading data having a predetermined Curie temperature and a predetermined magnetic coercive force, and a second magnetic film for reading data, formed on the first magnetic film, having a Curie temperature higher than the predetermined Curie temperature and a magnetic coercive force higher than the predetermined magnetic coercive force, and having a plurality of memory pits in series according to the information data to be recorded.

Abstract: In an information recording system, a semiconductor laser is energized in response to a drive current which is modulated in accordance with a recording signal in a recording mode so that a modulated laser beam is generated from the semiconductor laser. The modulated laser beam is focused on an optical disk and is reflected from the optical disk and the reflected laser beam is detected by an photo-detector. A detection signal from the detector is compared with a predetermined threshold level by a binary circuit and a relationship between the recording signal and an output signal from the binary circuit is detected by a detection circuit. In a overwrite mode in which the laser beam is focused on a pit or pits on the optical disk, an overwrite detection signal is generated from the detection circuit and the overwrite detection signal is counted by a counter circuit.

Abstract: An information recording apparatus includes a rotating section for rotating an optical disk at a constant angular velocity, the disk including a spiral recording track or concentric recording tracks, a recording section for recording information with a light beam irradiated on the recording tracks of said optical disk, the light beam having an arbitrary recording frequency, and control means for controlling the recording section such that the information is recorded on the optical disk while a pitch between adjacent record pits is elongated as a position of a recording track is moved from an innermost track toward an outermost track, the pitch at the innermost track being a first pitch, the pitch at the outermost track being a second pitch, the pitch at a track between the innermost and outermost tracks being longer than the first pitch and shorter than the second pitch, and the second pitch being shorter than a third pitch expected at the outermost track when the optical disk is rotated at the constant angul

Abstract: Prior to emitting a light beam from an optical head, an information recording apparatus moves the optical head in the direction of the optical axis so as to render the light beam in a defocused state on an optical recording medium. Then, the size of the emitted light beam is detected by a detector.

Abstract: An optical disc device includes an optical head for recording/reproducing information to and from an optical disc. The optical disc has two primary recording areas. On a first recording area of the two primary areas, the optical head records information so that the linear density of information is maintained constant. On a second recording area of the two primary areas, the optical head records information so that the spacing between adjacently recorded information increases with increasing radial position of the head or the recording position is further removed from the center of the optical disc. A substitute area is allocated such that the optical head records information in this substitute area when a defective memory portion portion is detected in the first and/or the second recording area during production or recording.

Abstract: An information processing system has a scanning apparatus which includes a brake mechanism for braking a turntable, on which an optical disk is mounted when the motor for rotating the turntable is stopped. A lock mechanism for preventing the optical head from moving is also activated. The lock mechanism operates in interlock with the brake mechanism when the brake mechanism is activated. The brake and lock mechanism are driven by a common drive source.

Abstract: An optical disc device includes a disc drive unit for driving an optical disc to rotate at a constant rotating speed, and an optical head for recording and reproducing data to and from the optical disc. A recording or a reproducing timing is determined according to the access position data for setting a recording position or a reproducing position on the optical disc. At the recording or reproducing timing as determined, data is recorded or reproduced at a constant linear density.

Abstract: An optical disk apparatus has an optical head for recording information on or reproducing information from an optical disk. The optical disk has a number of spiral or concentric tracks and a number of sectors formed along the circumferential direction of the disk. The sectors are divided into a plurality of sector blocks along the circumferential direction of the disk. Each sector block includes a different number of sectors which are continuous along the circumferential direction and which have a substantially constant linear length. A memory stores at least the speed data for maintaining a constant relative speed between the optical head and optical disk and is determined for each block group having a predetermined number of blocks. Speed data corresponding to the designated sector block is read out from the memory and is supplied to a velocity control circuit. A motor is driven to maintain a constant linear velocity between the optical head and the tracks of the optical disk.

Abstract: An image information processing apparatus comprises a rotational shaft for supporting five optical disks, subjected to read or write access, at predetermined intervals along its central axis, and two optical units, each having an optical head rotatable through 180 degrees to allow scanning of positions separated by 180 degrees. The optical heads are moved along the central axis of the rotatable shaft and in a radial direction of the optical disk between a scanning position where the optical disk can be scanned, and into a non-scanning position where the optical disk cannot be scanned. Thus the optical heads are moved to face different positions on the same optical disk or different optical disks.

Abstract: In a device for recording or reproducing information by using a light beam, there is provided an optical disk comprising a base plate, a recording layer formed on the base plate, tracks provided for recording information on the recording layer, and a focus check area for checking if the light beam is focused at the optimum position on the recording layer when an optical head which generates the light beam faces the recording layer. Accordingly, it is possible to change the focus position for the recording layer of the optical disk by the objective lens of the optical head during recording and reproducing information. Also, it is possible to set it at a position where the bit error rate is smallest and has a wider margin for the shaft of the adjust position.

Abstract: An optical disk apparatus has an optical head for recording information on or reproducing information from an optical disk. The optical disk has a number of spiral or concentric tracks and a number of sectors formed along the circumferential direction of the disk. The sectors are divided into a plurality of sector blocks along the circumferential direction of the disk. Each sector block includes a different number of sectors which are continuous along the circumferential direction and which have a substantially constant linear length. A memory stores at least the speed data for maintaining a constant relative speed between the optical head and optical disk and is determined for each block group having a predetermined number of blocks. Speed data corresponding to the designated sector block is read out from the memory and is supplied to a velocity control circuit. A motor is driven to maintain a constant linear velocity between the optical head and the tracks of the optical disk.

Abstract: An optical disk apparatus has an optical head for recording information on or reproducing information from an optical disk. The optical disk has a number of spiral or concentric tracks and a number of sectors formed along the circumferential direction of the disk. The sectors are divided into a plurality of sector blocks along the circumferential direction of the disk. Each sector block includes a different number of sectors which are continuous along the circumferential direction and which have a substantially constant linear length. A memory stores at least the speed data for maintaining a constant relative speed between the optical head and optical disk and is determined for each block group having a predetermined number of blocks. Speed data corresponding to the designated sector block is read out from the memory and is supplied to a velocity control circuit. A motor is driven to maintain a constant linear velocity between the optical head and the tracks of the optical disk.

Abstract: A position detecting apparatus provided with a photosensor for optically detecting the scale pattern of an optical scale which moves together with the optical head of the optical disk instrument, and generating an analog signal which corresponds to a pitch of the scale graduation. The photosensor has a light receiving surface, whose width is half the pitch of the scale graduation, and the analog signal of the photosensor is converted to digital signals by means of an A/D converter the digital signals corresponding to a pluralty of level signal components of the analog signal. The digital data thus obtained are added or subtracted according to the moving direction of the optical head, thus enabling the position of the optical head to be detected.

Abstract: A data recording apparatus has an optical scanner for optically scanning a document and for outputting an image signal corresponding to the document pattern, a modified Huffman coding circuit for compressing the image information output by the optical scanner for each scanning line, and a page buffer memory for storing the image signal compressed by the modified Huffman coding circuit as line image information items. The line image information items are read out from the page buffer memory in units of a fixed number of bits, and are divided into image data pieces of a fixed bit length. Dummy data is added to the terminal end image data which does not have the fixed bit length, thus forming a terminal end image data of the fixed bit length. Error correction data is set for each image data piece.

Abstract: A document information filing system has a function of displaying a plurality of its operation modes such as "SEARCH", "RECORD", "DELETE" and "CHANGE" modes on a display device. When a given operation mode is selected by a keyboard, sequential guidance for the procedure of operation for the selected operation mode is displayed on the display device, whereby the operation of the selected operation mode can be executed by operating the keyboard in conformity to the display guidance.

Abstract: Increased recording speed is possible, in a system in which an endless recording medium is used to record units of information, by dividing the medium, in the direction of its length, into at least first and second successive regions. Several units of information can be recorded during a single excursion of the endless medium by recording the first, n+1, 2n+1, 3n+1 . . . units in the first region and the second, n+2, 2n+2, 3n+2 . . . units in the second region, where n equals the total number of regions. This system is suitable for use with a recording medium which has plurality of parallel information recording tracks. Another expression to describe which information units are recorded in the jth region is (k-1)n+j, where j and k are positive integers.

Abstract: A recording and reproducing system which uses a recording medium having a plurality of information recording tracks for recording image information. And at least one index recording track is located on the recording medium for recording index information. The index recording track is located substantially at the center of the recording medium and extends length wise of the recording medium in the direction of movement of this recording medium. Accordingly, the recording medium of the present invention eliminates the adverse effect of the drop-out and reduces the period of time required to search for the index information and reproduce image information.

Abstract: Apparatus for positioning a magnetic head at a position corresponding to a reference track for use in a magnetic tape apparatus, in which the magnetic head is moved by a stepper motor in a direction perpendicular to the running direction of a magnetic tape formed with a plurality of data tracks. A detector such as a microswitch for detecting the arrival of the magnetic head at the neighborhood of a position corresponding to the reference track is provided. A control circuit stops the stepper motor for stopping the magnetic head at the reference position in response to the excitation of a previously selected phase winding of the stepper motor after detection of the arrival of the magnetic head at the neighborhood of the position corresponding to the reference track by the detector.

Abstract: In a picture information filing system using an endless magnetic tape (43), which has a plurality of picture information recording tracks (48.sub.2) for a plurality of units of recording two-dimensional picture information (3) in predetermined blocks and an index information recording track (48.sub.1) for recording index information for the individual unit picture information, the index information is temporarily stored in a random access memory (13) as unit index information groups each consisting of a predetermined number of index information items, recording start index information consisting of a peculiar code and an address representing the position from which to record the next picture information is added to the last index information item in the last index information group, and the individual index information groups are recorded in predetermined blocks of the index information recording track, each index information group in each particular block.