Abstract: A method and apparatus for providing a dynamic fine track seeking operation that adaptively fine tunes the entrance criteria used to determine when the head is on track for the specific disc drive under actual operating conditions. The method and apparatus includes adaptively modifying entrance criteria individually for each head in a disc drive according to actual operating conditions with the use of stored entrance criteria for each head, an extra track proximity threshold and a successful entrance counter.

Abstract: An apparatus for measuring the clearance between a recording transducer and a recording medium, which includes at least a conductive layer or conductive section, comprises a field electron emission electrode section disposed on the recording transducer, a voltage source for applying a voltage, which is greater at least in its peak value than the work functions of the electrode section and the conductive layer or conductive section of the recording medium, between the electrode section and the conductive layer or conductive section of the recording medium, a current measuring device for measuring the current flowing from the voltage source to the electrode section and the conductive layer or conductive section of the recording medium, and a computation processor for calculating the distance between the electrode section and the recording medium from the value of current measured by the current measuring device.

Abstract: A track search apparatus is composed of an actuator such as voice coil motor for moving a light beam to traverse tracks, a position detector for detecting that the light beam has reached a predetermined position in front of a target track, a velocity detector for detecting the velocity of the light beam, and acceleration/deceleration controller such as microcomputer for applying, to the actuator, a driving signal according to the output from the velocity detector when a signal is generated from the position detector.

Abstract: A track search circuit includes a command decoder which decodes command data sent by a microcomputer and stored in a command register and outputs signals commanding a track jump and commanding count of a counter which counts a tracking error signal. Time difference between a present A-time and a target A-time is calculated such that an optical pick-up can be moved toward a target position by utilizing the track jump of 4.sup.n. When a counted value of the counter reaches a predetermined value, the A-time is renewed such that the time difference can be reduced by addition or subtraction suitable time data to or from the A-time. If the renewed A-time becomes within 1 minute with respect to the target A-time in repeating such a track jump in accordance with the renewed A-time, the optical pick-up is stopped to move, and the A-time is read to jump the optical pick-up again to catch the target position.

Abstract: An optical recording system including a read/write optical assembly including an objective lens for reading or writing from an optical medium including a solid immersion lens disposed between the objective lens and having a surface closely spaced from the recording medium.

Abstract: An amplitude difference between a reproduction signal from a preformat portion of an optical disk and a reproduction signal from a recording portion of user's data is obtained. When the amplitude difference exceeds a predetermined value, a first gain value which was set for information from the preformat portion is used as a gain value of an AGC circuit for reproduction and a gain control of the reproduction signal is performed. On the other hand, when the amplitude difference is smaller than the predetermined value, a second gain value which was set for the user's data is used. Thus, a situation such that a noise and a remaining signal of the user's data which was not erased are erroneously recognized as an inherent reproduction signal can be prevented. A discrimination to see if the data has been recorded in the recording portion of the user's data or not can be also accurately performed.

Abstract: A disc player operates in a manual search mode in which play and jump operations are alternately repeated, in response to a manual search command, while maintaining the reproducing level at a level lower than the level at the initiation of the manual search command as long as no change command appears.When the change command appears the reproducing level is shifted to a level which is designated by an operator so as to adjust the reproduced sound level to a level sufficient to listen to the reproduced sound for music selection.

Abstract: A disc playing apparatus allows to set the reproduction speed of subcode information at a designated speed. The subcode read-out by a reading device is decoded by a decoding device and each piece of digital data successively output from the decoding device is transmitted at a predetermined transmission rate. The interval between pieces of the digital data is varied in response to a designated reproduction speed, and at the same time each piece of the digital data is transmitted at the predetermined transmission rate.

Abstract: For a disk drive having a servo positioning system for moving and positioning a read/write head in track seeking and following operations, a velocity estimator connected to derive velocity signals selectively from a plurality of position signals, the phasing of said position signals being such that at least one of the signals at any given radial position of ther head varies linearly with radial head displacement, that is, with a constant change in signal level per unit of radial displacement. The phase of the position signals are such that as one position signal is about to leave its linear operating region, another is in its linear operating region. The velocity estimator comprises a plurality of sections each selectively switched to receive and differentiate a position signal and connected so that there is not current surge resulting form such switching.

Abstract: In a digital tape recording system for video and sound signals, in which information in each track is stored in plural sectors having synchronizing preambles that aid in synchronizing the playback of the information, special preambles containing a frequency component that is lower than normal are used for the first sector of the first track in each video frame or field. The normal and special preambles are produced by passing the binary code". . . 01010101 . . . " (in the case of all but the first sector of each frame or field) or ". . . 011011011011 . . . " (in the case of the first sector) through a Miller Channel Code encoder to produce, in the first case, a synchronizing square wave fluctuating at one-fourth the bit presentation frequency, and in the second case, a synchronizing square wave fluctuating at one-sixth the bit presentation frequency.

Abstract: A positioning controller can position a head at a starting position of an unrecorded region on a disk in a shorter time than a conventional positioning controller, information being recorded on the disk by means of the sequentially inner-to-outer recording method or the sequentially outer-to-inner recording method. The positioning controller judges whether or not information is recorded at a predetermined position on the disk, and then executes the binary search method in a recording direction from the predetermined position of the disk when judged the information is recorded at the predetermined position or in a direction opposite to the recording direction from the predetermined position when it is judged that the information is not at the predetermined position. Therefore the direction in which searching by the binary search method is executed is determined by the above judgement.

Abstract: An apparatus for detecting a deviation of reading position for use in a disc player. A detection signal of the deviation of reading position is generated if a sync signal to be extracted from the read-out signal is not yielded for a predetermined time period under the presence of a lock detection signal which is produced when the focus servo system is in a locking condition. Owing to this structure, the deviation of the information reading light spot from a proper position is surely detected without enlarging the scale of circuits in the disc player.

Abstract: An optical recording/reproducing apparatus for recording and reproducing an information through irradiating a light beam on a recording medium has a separation type construction including a stationary section and a movable section which is movable across recording tracks on the recording medium. The stationary section includes a light source and detectors for detecting data signal and servo control signal from the light beam reflected by the recording medium, while the movable section includes a mirror for reflecting the light beam from the light source to allow the light beam to impinge upon the recording medium perpendicularly thereto, and a lens for converging the light reflected by the mirror onto the recording medium. The mirror and the lens are disposed such that a distance between the mirror and the principal point of the lens is substantially twice as large as the focal length of the lens.

Abstract: A disc player having digital processing of error signals in a servo system utilizes an A/D converter. The relatively small closed loop error signals are amplified by a predetermined amount above that for the open loop error signals prior to conversion in the A/D converter, and the converter output representing the digitized small error signals are amplified by a predetermined amount below that for the digitized open loop error signals. While the overall gain in the servo system is substantially the same for the closed loop and open loop error signals, the small closed loop error signals are greatly expanded in range at the converter input to permit the same A/D converter to faithfully convert both the open loop and the closed loop error signals.

Abstract: A transducer access control system for use in a disk recording/reproducing apparatus for moving a transducer a required distance from its present position over a disk in the radial direction thereof, includes a linear motor for driving the transducer, a circuit for generating a distance signal indicative of the required distance for moving the transducer, and a calculator for calculating a half distance which is a half of the required distance. To move the transducer for the required distance D, the linear motor is operated at the velocity controlled in accordance with a reference velocity signal produced from a reference velocity generator. The reference velocity is determined such that, the reference velocity is maintained at a predetermined value during the movement of the transducer in the first half of the required distance, and gradually decreases during the movement of the transducer in the second half of the required distance.

Abstract: A random access information storage disk drive system of the optical or magneto-optical type with the read/write head mounted between parallel flexures for suspension in a linear actuator motor. Dynamic spring force compensation is provided incrementally as the head is moved radially inward and outward of the at-rest position of the flexures to compensation for the increasing restoring force exerted by the flexures as the head is moved towards the extremes of its tracking path.

Abstract: A track access control circuit of an optical disk unit comprising a track actuator (14) with an object lens driven at a relatively high frequency and a positioner for moving the track actuator at a relatively low frequency, a beam moving velocity or a target velocity of the positioner being modified and applied as a driving current to the positioner for preventing a tracking delay of the positioner from occurring during a seek operation.

Abstract: An apparatus for detecting a moving direction of a light beam spot illuminated on an optical information recording medium having tracks, in which moving direction identifying signals are obtained in synchronized with a leading edge and a trailing edge of a tracking error signal and a prohibit signal for prohibiting to write and rewrite information of the moving direction of the light beam spot is generated in accordance with the moving direction identifying signals. In the apparatus according to the invention, writing and rewriting the information of the moving direction of the light beam spot is prohibited when the two moving direction identifying signals denote opposite moving directions, so that the moving direction of the light beam spot on the optical information recording medium can be detected without being influenced by a prepit, a dust or a flaw formed in the optical information recording medium.

Abstract: The present invention describes a time based servo pattern scheme which provides position and velocity information with high accuracy. A plurality of servo lines are formed on a data disk extending from the inner track to the outer track, In the preferred embodiment of the present invention, these lines are employed as part of a buried servo scheme such that the entire useable disk surface is dedicated to data storage. The servo pattern is written on each side of the disk so that, if the disk were transparent, the respective servo lines would appear to intersect when viewed from above. Servo heads located on each side of the disk detect servo line crossings. By comparing the time difference between crossings of corresponding tracks on either side of the disk, the radial position of the heads can be determined. Therefore, even when nominal track centers do not fall on servo line intersections, their position can be determined accurately.

Abstract: An apparatus for playing a disc on which, in addition to a coded information signal, a digital information signal divided into blocks is recorded as a subcode together with a block identification signal for identifying the blocks, comprises a reading device for reading the coded information signal and the subcode from the disc, a decoder for decoding the subcode to produce an information signal, a repeater for repeating the subcode read out by the reading device to the decoder in response to a repeat command, and a controller for controlling the reading device and the repeater.

Abstract: The present invention relates to a voice coil motor with an encoder. In a voice coil motor whose rotor rotates in a prescribed angular width to a base, a rotary disc for encoding is attached to the fringe section of the rotor, and an encoder is provided on the base corresponding to the track of the rotary disc. Attaching the rotary disc to the fringe section of the rotor, the length of the track can be long, so that number of slits perforated on the rotary disc can be increased. Therefore, resolution of the angular position of the rotor can be high.

Abstract: A signal reproducing device for an R-DAT employing offsetting of the tracking error signal in which the digital error rate is significantly reduced. A head assembly traces tracks on which predetermined digital data and tracking pilot signals have been recorded, the head assembly having a larger tracking width than the tracks. The pilot signal is detected from the reproduction output of the head assembly to form a tracking error signal. The level of the RF signal reproduced by the head assembly is detected and is compared with predetermined reference values. An offset signal is added to the tracking error signal according to the comparison result. A servo circuit controls the tracking conditions of the head assembly according to the addition result.

Abstract: A disk drive system has a closed loop servo control system which is specially tuned for optimal deceleration during performance of a track access operation. The servo control system is returned in response to a track jump signal to perform a track jump operation at a lesser deceleration and thereby reduce low frequency acoustic noise produced by physical vibrations of the disk drive system. The returning of the servo control system is advantageously achieved by reducing the gain-bandwidth product of the closed loop within the servo control system.

Abstract: A record disc reproducing apparatus, which can be used for searching for a desired track location rapidly, including a pick-up device for reading data from the disc and which is movable is a radial direction with respect to the disc and a driver for driving the pick-up device radially with respect to the disc. The moving velocity of the pick-up device is detected and used to produce a velocity signal corresponding to the moving velocity. A kick signal is generated to energize the driver and is controlled so that the velocity signal approaches a predetermined reference velocity value. During track seeking the apparatus eliminates or removes the effects of phase compensation used during reproduction.

Abstract: A data reading device for use in a disc player including a pickup device for reading data from a disc, a pickup transfer motor for moving the pickup across the disc in a radial direction in response to a speed control signal, a pickup transfer speed detector for detecting the radial speed of the pickup and generating a speed signal representative of the speed, a target position signal generator for generating a position signal corresponding to a desired radial position on the disc, a microcomputor for calculating the location of the pickup with respect to the disc and generating a location signal corresponding to the location, a comparator for generating a distance signal representing the distance between the location of the pickup and the desired position using the position signal and the location signal, nonlinear attenuator for attenuating the speed signal in a nonlinear manner based upon the value of the speed signal and a pickup drive circuit for generating the speed control signal from the distance sign

Abstract: Means for reducing the effects of vertical perturbations of a phonograph disc surface resulting from disc and/or playback system mechanical imperfections. Such imperfections are compensated by closed loop and/or open loop means wherein the deviations of the record path are detected and employed to minimize the effects of the mechanical imperfections.

Abstract: A disc data reproducing apparatus, including a rotating mechanism for rotating the disc about a central axis, an optical head disposed opposite the disc for receiving data from the disc, and a moving mechanism for moving the optical head along the radial direction of the disc. The optical head is disposed on one side of the central axis of the rotating mechanism and the moving mechanism is disposed on the other side of the central axis so as to reduce the space requirements for housing the head and moving mechanism within the apparatus.

Abstract: A disk file digital servo control system utilizes a state estimator wherein the voice coil motor (VCM) current is modeled, rather than measured, thereby eliminating the need for analog-to-digital conversion of the actual VCM current. The VCM current is fed back directly to the input to the power amplifier where it is summed with the control signal output. This effectively changes the integrating power amplifier into a low pass filtering power amplifier, with linear input-output characteristics. Thus, during track following or short seeks, the VCM current is estimated based on this linear model. During long seeks, when the power amplifier is saturated, the VCM current is modeled based upon the known VCM characteristics during saturation, which include the effects of the back electromotive force and the coil current rise time. The microprocessor in the digital servo control system determines which VCM current model to use by a determination of when the power amplifier is in saturation.

Abstract: An optical disk reading apparatus having a carriage on which a tracking actuator and a photosensor unit are mounted and driven by a head actuator for moving a spot of a light beam in a direction traversing tracks on an optical disk and for detecting first position and second position signals indicative of the position of the spot on the tracks through addition and subtraction of the electric signals corresponding to changes in the quantities of light reflected from the tracks upon the movement of the spot and including circuitry for accurately placing the spot on a desired track of the disk even when the first and second position signals contained omissions.

Abstract: An optical disk storage access method using a fine and coarse actuators for positioning a light spot to an intended track on the disk, wherein a pulse is generated each time the light spot has traversed a track, the pulses are counted to determine the distance from the current spot position to a target track, the fine actuator is activated depending on the measured distance, and the fine and coarse actuators are operated in unison so that the light spot is positioned to the target track.

Abstract: A method and apparatus for scanning a rotating optical disc record carrier with a radiation beam which forms a scanning spot on the carrier and which is moved radially relative thereto. Pulses are generated at a frequency proportional to the angular velocity of the carrier, and clock pulses are generated at a constant frequency differing from and preferably higher than that of the velocity pulses. In response to each velocity pulse an accumulator is incremented by a first correction value (INC) and in response to each clock pulse the accumulator is decremented by a second correction value (DEC). The angular velocity of the record carrier is controlled to maintain a constant value of the average of the sum output of the accumulator over the intervals between successive velocity pulses, and the correction values are adjusted so that the ratio thereof is maintained proportional to the radial distance between the scanning spot and the axis of rotation of the carrier.

Abstract: Pick-up control circuits for disc information reproducing apparatus. The apparatus includes a carriage, a source of a light beam mounted in the carriage, a focus lens for placing the light beam on a disc, the focus lens being mounted on a standard position in the carriage but movable by a prescribed range from the standard position, a circuit for detecting a tracking error signal responsive to a deviation of the light beam from a center of the track, a lens actuator for driving the focus lens to deviate from the standard position, a carriage actuator for driving the carriage to move in the radial direction in respect of the disc, a power source for applying a drive voltage to the carriage actuator, a switch connected between the power source and the carriage actuator, and a circuit for controlling the switch to apply the drive voltage intermittently to the carriage actuator, so that focus lens is moved to the standard position on or before reaching an end of the movable range.

Abstract: Process for track jumping in track searching process for a rotating information carrier scanned with an optical system, in which the system works in conjunction with a radial coarse (13) and fine (3) drive system. If the coarse drive is immediately put into operation in accordance with the input search direction, the servocircuit of the fine drive system is initially closed and is only opened as a function of criteria prevailing at the time. In this process and in the circuit arrangement envisaged for its implementation, the principal advantage is a high search speed and considerable initial acceleration. In particular, the movement overlaps occurring in the starting phase do not present a problem for the perfect operation of the process.

Abstract: A system for recovering information from a videodisc and performing special functions which enhance the operational character of the system. To increase the reliability of landing at or near a target track, provisions are made to search for a track adjacent a target track whose track identifier has been obliterated. Further, a method and means for stepping forward or reverse one field at a time is disclosed. Another aspect of the invention concerns a capability to respond to a random command instruction resulting in subsequent functioning of the system in a random manner. Yet a further aspect of the invention is related to controlled jumping of one or more tracks during vertical blanking time to produce unique forward or backward motions; multiples of playing speed, both forward and reverse, and visual special effects can be realized using the multiple track jumping feature. Finally, a method and means are described which permit synchronous transmission of video from a videodisc to an external using device.

Abstract: Disclosed is a Fine positioning arrangement for track-follow servo means in a disk drive arrangement wherein servo head output is processed logically to indicate violation by the head of a near-boundry or a far-boundry for prescribed times to indicate whether the transducer is truly "on-center" or not and to logically exclude noise and other error conditions that might compromise this indication.

Abstract: An optical pickup is provided below an optical disk. A laser beam is emitted from a semiconductor laser onto a track, through an objective lens. The objective lens is capable of shifting, and is shifted in the direction of the track width by a magnetic force from a tracking actuator, thereby performing lens tracking. The optical pickup is mounted on a carriage. The carriage is shifted along the radial direction of the optical disk by a voice coil motor. This shifts the laser beam along the radial direction of the optical disk, thereby performing track access. Upon reception of an access command, a velocity control mode commences, and the shift velocity of the carriage is controlled in accordance with a velocity control signal corresponding to the distance between a target track and a current track. When the pickup arrives near the target track, the generation of velocity control signal ceases and the location control mode commences.

Abstract: A device for tracking a rotary recording medium includes a playback head for reading a signal from any of a plurality of tracks which are formed on the rotary recording medium, which is rotating at a predetermined constant speed, such that a beginning and an end of a recording in each of the tracks coincide with each other, a head support mechanism supporting the head such that the head is movable along the recording medium, an arrangement for detecting an envelope of a signal which is read out of the recording medium by the head, and a controller for controlling the head support mechanism to move the head to a position where a desired one of the tracks is located. An arrangement for detecting a position of the head relative to the recording medium and an arrangement for detecting a rotation phase of the recording medium are provided.

Abstract: To accurately achieve plural-track jump operations at high speed in an optical disk apparatus, a first embodiment is provided in which an analog track jump signal is applied to move an optical beam. The analog track jump signal includes a kick pulse for acceleration, a constant pulse for constant drive, and a stop pulse for deceleration. In a second embodiment, a digital track jump signal is applied to move an optical beam. An erroneous track jump detecting circuit is additionally provided for detecting whether the optical beam correctly jumps over a designated number of tracks by comparing a number of plural track jump signals corresponding to the designated number of tracks to be jumped with the number of track signals generated when the beam jumps across a track.

Abstract: A tracking control system for controlling a relative positional relation between an optical pick-up and a rotating optical disc is provided. A tracking error signal is supplied to a low pass filter, to a lead phase compensating circuit and also to a zero cross comparator which supplies its output to a pulse generating circuit. During a normal tracking mode, in which the optical pick-up is maintained in alignment with a recording track of the rotating disc, an output from the low pass filter and an output from the lead phase compensating circuit are added to define a feed-back signal which is then supplied to the optical pick-up.

Abstract: A data recorder employs a disk record having a spiral track with either magnetically or optically sensible indicia. A normal mode of operation is to repeatedly scan one turn or circumvolution of the spiral track for emulating a circularly closed track. The recorder responds to received commands from a utilization device to tailor the disk access and recovery operations to the received command based upon command parameters and current status of the disk record. Electrical circuit and programming arrangements for effecting the controls are disclosed.

Abstract: Method and apparatus for seeking a desired one of a plurality of tracks formed on an optical information carrier are disclosed. The tracks are scanned by a light spot traversing the tracks, the tracks traversed by the light spot are detected, and the tracks detected are counted by a counter. When the light spot traverses a defect area on the track, the track which is not detected because of the defect area is also counted by the counter.

Abstract: A reproducing apparatus for reproducing a disc type signal bearing medium, which includes a reproducing transducer head and an automatic tracking control device for aligning the head with a selected track of the medium. The control device includes an electromechanical converting element for moving the head, a signal producing circuit for producing a tracking control signal based on the reproduced signal, a memory circuit for memorizing the control signal, and a switching circuit for selectively connecting the converting element with the signal producing circuit and the memory circuit. In a single track reproducing mode, the switching circuit connects the converting element with the signal producing circuit, and in a successive track reproducing mode, the switching circuit connects the converting element with the memory circuit.

Abstract: A light beam for recording, reproducing, and erasing information is divided by a half mirror into a transmitted light beam directed to a recording medium and a light beam for detecting a position of a reflected movable optical pickup. Since no additional light source is necessary for detecting the position of the optical pickup the apparatus is small in size, low in cost and reduces the number of adjustments required when the optical pickup is replaced.

Abstract: In order to reach precisely a predetermined place on an audio disk during a search run with contactless scanning, the scanning speed is determined from the speed of rotation of the disk. This occurs preferably at the beginning of the first recorded piece. The information concerning the speed of rotation of the disk is determined from the radial error signal. The arrangement is adapted for determining scanning speeds that vary among disks, and where each disk has a scanning speed that is unique to the disk and differs from the scanning speed of another disk.

Abstract: In order to obtain perfect scanning of audio and/or video disks through application of contactless scanning with a coarse and fine drive system for radial servo readjustment, the fine drive optimum working point is reached through a correct interaction of coarse and fine drive, even in the case of different large radial eccentricity amplitudes. This is achieved through adjustment of the coarse drive, using a comparator, as a threshold value detector, and through an evaluation of the pulse sequences occurring at the comparator output. A radial-error signal for the coarse drive is obtained from a control parameter for the fine drive. The coarse drive is started by pulses when the pulses obtained from a radial-error signal exceed a predetermined pulse-to-interval ratio.

Abstract: An information retrieval system adapted for an electronic dictionary comprises, an input device actuated for entering an entered word, a memory circuit adapted for storing a word equivalent to the entered word and the number of a track related to the word, a video disk for recording information related to the word, the information being random accessed, and an access circuit responsive to the number of the track specified by the memory circuit for accessing the video disk to access the information from the video disk.

Abstract: A disc information reproducing apparatus for reproducing information stored on an optical recording medium, the apparatus being subjected to expose to environments of varying temperature which produce condensation moisture in the apparatus. The apparatus includes an optical system for projecting the beam onto the optical recording medium for reflecting and modulating the beam in accordance with the information stored on the optical recording medium, an operating current generating circuit for generating a variable operating current in response to the reflected beam for controlling the optical system, a booster current source for selectively supplying a boasted current larger than the operating current to the optical system for generating heat in the optical system for removing condensation moisture from the apparatus.

Abstract: A write/read head comprises a laser whose resonator faces are formed by the storage medium and by a curved reflective surface which is positioned at a nominal distance from the medium and has a described residual radiant transmittance and a radius of curvature which is greater than the nominal distance. A mode diaphragm is provided between the active medium of the laser and the storage medium. Optical detector elements for the acquisition of position control signals and data read-out signals are arranged outside of the reflective surface and are symmetrically arranged with respect to the optical axis of the laser.

Abstract: A servo circuit for an information recording and reproducing apparatus such as a Compact Disc player detects relative mechanical vibrations of a pickup head with respect to a recording medium and changes a servo loop gain for positioning the pickup head to a high gain when the level of the detected mechanical vibration is high to obtain a high servo capacity and changes the servo loop gain to a low gain when the mechanical vibration is low to reduce power consumption and thereby minimize generation of heat. In one embodiment of the invention, an error signal due to mechanical vibration and one due to recording medium conditions such as spots and flaws of a disc are discriminated from each other by detecting acceleration applied to a main body of the apparatus.

Abstract: A transducer head, held in a fixed position as a preformatted disk is rotated a full revolution, reads any sector address accessible to the head. The addresses read come from a plurality of track revolutions that depend on the magnitude of the eccentricity of the disk. A computer, programmed with a least squares algorithm, first coordinates (1) data corresponding to the angular position of the disk each time an address is read, with (2) data corresponding to the actual radius of each address.