Abstract: The invention provides an improved disk writing system capable of storing larger amounts of information than heretofore possible. The disk mechanism incorporates a dual function servomechanism which includes a voice coil motor for driving the read/write head over long distances relatively quickly, and a stepper motor for precisely positioning the read/write head once it is in the desired region.

Abstract: The present invention provides a track format for an optical record carrier that is useful in producing a tracking signal with a substantially constant slope at its zero-crossing point for a range of track pitches. The preferred embodiment of track format is also useful in producing a tracking signal that has a substantially constant amplitude over a range of track pitches. The track format, in the preferred embodiment, employs wobbled pits. The sequence in which the wobbled pits occur alternates between adjacent tracks and the offset of the wobbled pits with respect to the center line of a track remain constant regardless of the track pitch. The preferred embodiment of the track format also includes a reference pit that is used to establish the threshold detection level for the read electronics. The location of the reference alternates between tracks to reduce the effect of radial interference on the signal produced using the reference pit and thereby allow an optimal threshold level to be established.

Abstract: A servo circuit for controlling an actuator provided on an optical pickup of a disc reproducing apparatus, the optical pickup optically reading out an information signal recorded on a disc is comprised of a phase compensating unit including a first phase compensator circuit whose gain characteristic and phase characteristic are set to first characteristics and a second phase compensator circuit whose gain characteristic and phase characteristic are set to second characteristics, the first and second phase compensator circuits being selectively coupled, a detecting circuit for detecting an oscillation of the actuator, and a switching circuit for switching the first and second phase compensator circuits from one to the other on the basis of an output from the detecting circuit.

Abstract: An optical recording and reproducing apparatus stably set the gains (focus, tracking) corresponding to the respective layers at the insertion time of a recording medium having a multilayer record membrane. The optical recording and reproducing apparatus uses a recording medium having a multilayer membrane construction wherein the recording membranes are formed in a stage shape, is not superposed in the inner periphery or the outer periphery with respect to the laser transmission side, and has a circuit for detecting the number of the recording membranes, and a circuit for switching to a focus gain or a tracking gain in conformity with the recording medium, and a focus driving circuit for effecting a focus drawing-in operation. The driving circuits are driven so that they may be rotated or run into a condition of effecting capable of focus drawing-in operation, and thereafter the focus drawing-in operation is effected in the specific position of the recording medium.

Abstract: A signal reproduction apparatus reproduces data from an information recording disc. The data is recorded for every data block and is modulated so that data in one data block has n (n is an integer) bits including arbitrary m (m is integer and less than the n) bits each having an active value. The signal reproduction apparatus includes, a reading circuit reading out the data from the information recording disc, a converter converting the data into a pulse signal for every data block, the pulse signal having an active pulse corresponding to the active value of the data and an inactive pulse corresponding to the inactive value of the data, a judgment circuit judging whether or not the pulse signal has m active pulses for every data block, and a correction circuit correcting the pulse signal so that the pulse signal has m active pulses in one data block when the judgment circuit judges that the pulse signal has a number of active pulses other than the m in the one data block.

Abstract: A check disc on which a single frequency signal is recorded on a check point next to an information signal of each track number and simulated defects such that the reproduction signal obtained by reproducing the disc becomes a defect signal in the case where defects occur on the disc are provided on the check point.

Abstract: A single loop servo is used for positioning a lens holding element with respect to an optical disk. The dynamic range of the error signal used in the positioning is dynamically frequency shifted such that the servo summing of the error signal with a reference signal (velocity reference) is always performed within the same dynamic range. This action simplifies circuit operation as the dynamic range of the error signal is compressed at high speeds. Two embodiments of the invention are described.

Abstract: An information recording/reproducing apparatus having two light sources, one of which is for use in recording information and the other one of which is for use in reproducing information, in which during action when information is recorded on an information recording medium in the apparatus, tracking errors of light beams emitted from the two light sources are corrected with the aid of a tracking error signal detected from reflection light beams of light beams emitted from a light source for use in recording information. Therefore, the light beams spot of the light beam for use in recording information can be positioned at a center portion of a data track without regard to a relative positional relation between the light beam for recording information and the light beam for reproducing information.

Abstract: A laser adjusting apparatus includes a laser source, a galvanomirror unit having a galvanomirror which reflects a laser beam from the laser source, and a device which adjusts the direction of the galvanomirror thereby changing the direction of the laser beam reflected by the galvanomirror. A second mirror which reflects the primary reflection light reflected by the galvanomirror unit toward the galvanomirror unit is also provided and a device which reflects the secondary reflection light reflected by the second mirror is made incident upon and reflected by the galvanomirror unit.

Abstract: An optical pick-up unit for an optical disk drive comprising a base plate secured to an optical block with an opening to enable a laser beam emitted by a laser emitter of the optical block to pass therethrough is disclosed. A support member is secured to the base plate opposite the opening and with a spring operatively secured thereto. A tracking damper is secured to the support member. A tracking support member is secured to the tracking damper and further includes a center of gravity with an insert hole formed therein. A support element extends through the insert hole and has a recess formed into each end of the support element. A pin is secured to the spring and another pin is secured to the base plate such that the pins are aligned with the insert hole and contact the support element, respectively. An objective lens is positioned over the opening and is secured to the tracking support member.

Abstract: In an apparatus for recording/reproducing data on a disc along a spiral track, a track-turn position of a record/reproduce head is changed in response to a kick back signal determined by a value of the register and read/write error signal just after a sector pulse or an address signal in addition to the conventional access command which changes the track-turn position through calculation from address included in the access command and the present address. The change of the track-turn position by the kick back signal makes access time shorter than that which would be done by the conventional access command. Moreover, in such apparatus, execution of the kick back operation is determined at every N sectors, wherein N=M-[T1/T2], where M is the number of sectors of one track turn; T1 is a time interval necessary for changing the record/reproduce head by one track-turn back; T2 is an interval necessary for scanning one sector by the record/reproduce head; and [T1/T2] shows a least natural number more than T1/T2.

Abstract: A shock load detection device mounted on a disk drive unit. The detection device is comprised of a piezoelectric polymer film encapsulated and electrically shielded by a metallic or metallic coated package. Electrical contacts are provided for on the piezoelectric polymer film and are connected to amplification and comparator circuitry which issues a write fault signal upon detection of external force in excess of a predetermined threshold. The shock sensor may be mounted on the computer disk drive of the unit in such a manner as to be at a 45.degree. angle to each of the x, y and z axis of the orthogonal coordinate system so that linear and torsional forces may be monitored.

Abstract: An apparatus for recording and reproducing optical information includes an optical integration detecting element arranged on an optical path of light from a laser beam source to an optical information recording medium.

Abstract: A device in which a radiation source generates a radiation beam of a first wavelength. The scanning spot 7 generated by this radiation beam follows the centerline 13 of a track 8 to be scanned on a first type of record carrier designed for this wavelength. When a second type of record carrier is being read, in which the information is stored in a phase structure designed for a wavelength which is longer than the first wavelength, the read spot 7 follows the edge of a track 38 to be read instead of the centerline 18. In this way it is possible to generate a satisfactory information signal not only from the first type of record carrier but also from the second type of record carrier.

Abstract: A disk reproduction apparatus having pause time setting device for setting a determined pause time upon receiving an instruction for successive reproduction; automatic pause setting device for setting the apparatus in pause during the pause time and releasing the apparatus from the pause after the pause time has passed; and search device for searching the next music program to be reproduced by moving an optical pickup, wherein the pause time is set to coincide with a time interval between an end of a current music program and a beginning of the next music program to be reproduced, independently of any recorded positions of the music program without making a configuration of the apparatus complex. Thus, when performing a random reproduction of the music programs, listeners can enjoy a natural flow of the successively reproduced music programs like when reproduction is performed of the music programs in order from an inner portion toward an outer portion.

Abstract: An optical-head drive having a guide member secured in the vicinity of the center of an optical disk, an optical head composed of a diffraction grating for splitting a light beam into two sub-beams, an objective lens for converging the sub-beams respectively on the optical disk and a member to be guided slidingly by the guide member, and driving means which moves the optical head to a desired radius location on the optical disk while swinging the optical head around the guide member for correcting the angle of the diffraction grating by making the member to be guided slide along the guide member. This configuration enables the correction of the angle of the diffraction grating to be performed simultaneously with the movement of the optical head.

Abstract: A data recording/reproducing apparatus for recording/reproducing data by use of a recording medium comprises a detector for receiving light beams from a predetermined portion of the recording medium and outputting a corresponding reproduction signal. A first measuring unit measures a time period during which an average level of the reproduction signal output from the detector exceeds a reference value, and outputs a first measurement signal. A second measuring unit measures the number of times, at which an interval of pits recorded on the recording medium meets a predetermined modulation rule, by use of the reproduction signal, and outputs a second measurement signal. A discriminating unit discriminates the recording state of the predetermined portion of the recording medium, on the basis of the first and second measurement signals.

Abstract: A recording method and corresponding recording apparatus adjusts at least one record carrier-dependent recording parameter (I.sub.s) which influences the quality of the recorded information pattern (58, 59). In determining an optimum setting of the parameter (I.sub.s) a calibration area (21) is selected from a predetermined number of such areas on the record carrier. The selected area is then provided with test patterns recorded at different settings of the recording parameter, and based on the test patterns thus formed an optimum setting of such parameter is determined in accordance with a predetermined criterion. The parameter is adjusted in accordance with such optimum setting thereof during the recording of the information pattern (58, 59). Each time such a calibration is performed an auxiliary pattern is recorded in an auxiliary area (22) assigned to the calibration area employed, which auxiliary pattern indicates that test patterns are present in such calibration area.

Abstract: A data recording apparatus is directed to a modulating/recording system for modulating data divided into a plurality of blocks and recording the modulated data on a recording medium. A byte sync signal output section outputs byte sync signals to be inserted between the plurality of blocks. A modulating section modulates data of one block while the byte sync signal output section outputs the byte sync signal. A modulated data storage section temporarily stores the data modulated by the modulating section. A modulated data read section reads out modulated data to be recorded from the modulated data storage section after the byte sync signal output section outputs the byte sync signal. The data to be recorded represents a predetermined arrangement regardless of recording directions.

Abstract: An automatic ejection system includes a loading device. The automatic ejection system has a grille detector for detecting the removing of a grille from a car stereo and for producing a detachment signal, a tape detector for detecting existence of a tape in the car stereo and for producing a tape signal, and ejection controller responsive to the detachment signal and the tape signal for operating the loading device so as to automatically eject the tape from the car stereo.