Abstract: A method for determining a track-cross direction of a pick-up head of an optical disk drive includes the following steps. (1) When a track-cross velocity of the pick-up head was determined to be greater than a predetermined velocity, it is determined whether the track-cross velocity of the pick-up head is changed to be less than the predetermined velocity. If not, the track-cross direction remains unchanged. (2) When the track-cross velocity of the pick-up head was determined to be less than the predetermined velocity, it is determined whether the track-cross velocity of the pick-up head is changed to be greater than the predetermined velocity. If not, the track-cross direction is determined according to a phase difference between a first track-cross signal and a second track-cross signal.

Abstract: A device and a method can judge the radial moving direction of light spots formed on the signal recording surface of an optical disc having grooves of two types that are different from each other in terms of depth and arranged along a recording track that is a land of the optical disc. The judging section of the device judges the moving direction of the main spot on the basis of binarized data of a difference signal of the main spot and binarized data of a difference signal of one of the side spots. With this arrangement, the moving direction of the light spots relative to a radial direction of the optical disc can be determined only by using difference signals without using any sum signal.

Abstract: A tracking controller capable of conducting a correct tracking control even if a recording track is formed with a narrow track pitch on a recording disk. The tracking controller calculates an error value between a read signal read from a recording track intended for reading and a predetermined value, a first coefficient from a correlation between a read signal read from a recording track adjacent to the recording track intended for reading on the inner peripheral side of the disk and the error value, and a second coefficient from a correlation between a read signal read a recording track adjacent to the recording track intended for reading on the outer peripheral side of the disk and the error value. A difference between the first and second coefficients is calculated as a tracking offset which is subtracted from a tracking error to correct a tracking offset.

Abstract: When a run-away phenomenon of an optical disk occurs, a control circuit detects a rotational direction of the optical disk that runs away by comparing an initial track count value and a braking time track count value. The initial track count value is a value calculated by counting track pulses corresponding to a tracking error signal for a predetermined time when a tracking servo is turned off. The braking time track count value is a value calculated by counting the track pulses corresponding to the tracking error signal for a predetermined time, when a brake pulse is applied to the spindle motor.

Abstract: A tracking control circuit includes a light receiving element divided in at least four sections. Of these, a group of divided light receiving sections located on a diagonal line obtains a first differential signal. A group of divided light receiving sections located on another diagonal line obtains a second differential signal. In accordance with the phase difference between the first and second differential signals, a tracking error signal is generated to make tracking control on a wobbled information recording track.

Abstract: A method for controlling an optical pickup head of an optical processing apparatus is provided. A first lead-lag compensator is disabled and a second lead-lag compensator is enabled when the optical pickup head switches from a following mode to a seeking mode. Then, an initial operating factor of the second lead-lag compensator is determined according to a last input value and a last output value of the first lead-lag compensator. An initial kick force of the actuator in the seeking mode is calculated by realizing the last input value and the last output value of the first lead-lag compensator immediately before the first lead-lag compensator is disabled. Finally, the optical pickup head is actuated to perform a seeking operation with the initial kick force.

Abstract: In a disk device, a focus servo activating circuit causes an RF amplifier 3 to amplify a focus error signal within a predetermined gain adjusting range, causes a control circuit 4 to multiply the amplitude of the focus error signal obtained by the RF amplifier 3 by two coefficients to calculate two threshold values, and starts up a focus servo upon the amplified focus error signal passing the two threshold values. The focus servo can be started up normally even for optical disks of extremely low reflectivity.

Abstract: In a method of the present invention for controlling stepping motor, the stepping motor driving current is increased or reduced at a fixed inclination in proportion to the time to control the stepping motor effectively, and, a stepping motor driving current pattern is changed by ¼ cycle or more to synchronize the state of excitation between the stepping motor driving means and the stepping motor to control the pick-up very accurately. In addition, the disk apparatus of the present invention, which uses a stepping motor is provided with a pulse rate pattern variable means, a pulse rate change proportion measuring means, and a driving voltage variable means, and when the pulse rate and the pulse rate change proportion are low, the driving voltage amplitude is lowered to reduce surplus torque generation in the stepping motor.

Abstract: An optical disc drive includes: an optical head with an actuator and a photodetector; a tracking driver outputting a drive signal to the actuator; a first tracking error signal generator for generating a first tracking error signal based on an output signal of the photodetector; first and second lens position control sections for respectively outputting first and second lens position control signals to the tracking driver; and a selector for selectively supplying the first tracking error signal to the first or second lens position control section according to a moving velocity of the optical head during a seek operation. The first lens position control signal is obtained by extracting signal components, of which the frequencies are equal to or lower than a predetermined frequency, from the first tracking error signal. The second lens position control signal is obtained by extracting DC components of the first tracking error signal at on-track points thereof.

Abstract: An optical recording medium driving apparatus which can obtain a tracking error signal necessary for an accurate track count. An optical recording medium driving apparatus for recording and/or reproducing data in/from an optical recording medium, where information can be recorded in plural tracks formed by land portions and groove portions provided between the land portions, based on a light emitted to the tracks. The apparatus includes a detector for detecting a position of the emitted light, a peak-hold circuit for holding a peak of a position detected signal outputted from the detector so as to output the position detected signal, a bottom-hold circuit for holding a bottom of the position detected signal so as to output the position detected signal, and a switching circuit for switching signals based on the output signals from the peak-hold circuit and bottom-hold circuit so as to output either signal.

Abstract: A liquid-crystal panel is placed in an optical path of an optical beam from a light source to a recording surface of a recording medium for compensating wavefront aberration of the optical beam by giving a phase difference to the optical beam. The liquid-crystal panel comprises a layer of a liquid crystal material having an index of birefringence, wherein the product of the index of birefringence and thickness of the layer of the liquid crystal material is 0.4 &mgr;m or more.

Abstract: A method and apparatus for reproducing data from an optical disc which has a plurality of recording layers reproducible from one side of the optical disc, and in which the disc is recorded in the OTP (Opposite Track Path) type. Upon receipt of a command of pausing, a pausing operation is performed by switching a moving direction of a focal point of an optical pickup in accordance with layer information of the recording layer to be currently reproduced.

Abstract: Disclosed herein is a method of compensating for variations in the track pitches of optical discs. The method includes the step of activating a focus servo and inactivating a tracking servo so as not to trace the tracks of the optical disc. Thereafter, the pickup assembly is transferred across the optical disc to generate the traverse signal caused by differences between the amounts of light reflected by the tracks of the optical disc and the other portions of the optical disc. The traverse signal is shaped into a pulse wave, and the number of pulses of the traverse signal is counted. The rotation number of the optical disc is measured and stored. The track pitch of the rotating optical disc is calculated. Finally, a target track number is calculated, and a seek operation is performed.

Abstract: A disk apparatus includes a disk having helically-formed tracks and storing information on said tracks; a motor for rotating said disk; a pick-up means having a focus servo means and a tracking servo means for reading information recorded on said disk by following the information stored on said tracks; traverse means having a stepping motor for moving said pick-up means by a specified distance; pulse generating means for generating pulse signals for controlling said stepping motor; stepping motor driving means for driving said stepping motor according to said pulse signals received from said pulse generating means; a step-out detecting means for detecting a step-out of said stepping motor; and a driving voltage changing means for changing a driving voltage of said stepping motor when said step-out detecting means detects the step-out in said stepping motor driving means.

Abstract: A method for track seeking of a reading head in an optic disk drive is disclosed. In seeking a track in a disk. the track number and the direction in the fine seek are used for adjusting a voltage waveform in the rough seek. The variation of an optic disk drive due to mechanic friction or torque variation of motor can be overcome so as to achieve the same accuracy as being installed with a speed sensor. Since no speed sensor is required to be installed on the track seeking means, the cost in manufacturing is reduced greatly.

Abstract: A center error signal is used to control the sled during fine search operations. The center error signal is used to synchronize the motion of a tracking actuator and a sled. A head is mounted on a sled in a disk drive. The sled is positioned by a sled motor and the head is positionally mounted on the sled. The head includes a lens that is optically coupled to a photo-sensor on the head. A tracking actuator positions the lens with respect to a track on the disk. A center error signal indicates a position of the lens with respect to a track on a disk. A tracks-to-jump signal specifies a predetermined number of tracks on the disk that the sled motor is to move. A modified tracks-to-jump signal is produced in response to the center error signal. The sled motor is controlled with the modified tracks-to-jump signal.

Abstract: A radio frequency ripple zero crossing signal calibration method for an optical disk reader undergoing a track following to track seeking transition is disclosed. The method utilizes sampling to obtain radio frequency ripple peak level during a track seeking operation and radio frequency ripple DC level during a track following operation and using their differences as a calibrated value. Through the calibrated value, the radio frequency ripple zero crossing slice level is modified so that a correct radio frequency ripple zero crossing signal is obtained during a track following to track seeking transition. In a track following to seeking transition, this arrangement prevents distortion of the radio frequency ripple signal and corresponding drift in the radio frequency zero crossing signal that may lead to errors in computing moving speed and counting tracks of the pickup head. Hence, search capacity of the optical disk reader is improved and the pickup head is better controlled.

Abstract: This invention relates to a servo-control method and servo-controller of a memory storage device, as well as the memory storage device, for positioning the reading position of a head on a target position. It suppresses phase lag in the high region while preventing a decrease in follow-ability. This invention comprises a storage medium 72, head 76, actuator 60, detection circuit 48, and control circuit 16. The detection circuit 48 detects the amount of shift between the reading position of the head 76 and a target position. The control circuit 16 performs PID calculation for the shift amount and outputs an instruction value for the actuator 60. There is a limiter 121 for limiting the calculated result of the differential component of this PID calculation to a specified value. Only the high region is limited and the low region is not limited, thus it is possible to suppress phase lag in the high while maintaining follow-ability.

Abstract: In track jumping or focus jumping in an optical recording and reproducing apparatus for an optical disk, a light beam is accelerated and decelerated from a track to an adjacent one or from an information plane to an adjacent one in the optical disk. A moving time of light beam under acceleration to an adjacent track or information plane for jumping is measured from the start of acceleration to a predetermined point according to tracking o focus error signal. Then, the deceleration signal for tracking or focus actuator is changed on amplitude or period according to the measured period. Thus, track or focus jumping can be performed stably against external disturbances. Alternatively, the light beam is forced to be driven until the level of the tracking or focus error signal is decreased below a predetermined value after the output of the deceleration signal is completed.

Abstract: A storage apparatus has a function of jumping to an arbitrary track on a recording medium in response to a track jump request when making access to the recording medium, where the recording medium is divided into a plurality of zones in a radial direction thereof and employing a ZCAV system. The storage apparatus includes a zone recognizing part recognizing a zone to which a present position on the recording medium belongs, and a jumping part jumping to a first zone to which the arbitrary track belongs or to a second zone which is adjacent to the first zone, based on the zone recognized by the zone recognizing part.

Abstract: A learning control unit is provided between a feedback calculating unit and a driving unit. When a period for one medium rotation period is assumed to be TL, an unknown drive current function Irepeat(t) which repeats for a period of time from a start time t=0 for one medium rotation period to an end time t=TL is obtained by a learning algorithm as an approximated function I{circumflex over ( )}repeat(t) that is approximately presumed by a set of the heights Ci of N rectangular functions having interval numbers i=0˜ (N−1) whose time widths are obtained by dividing the period for one medium rotation period into N intervals. After the learning, a learning control signal I{circumflex over ( )}repeat is outputted synchronously with the medium rotation and a feed-forward control is performed.

Abstract: Method for tracking in an apparatus for reading from and/or writing to an optical recording medium, and corresponding apparatus for reading from and/or writing to an optical recording medium. In order, in an apparatus for reading from and/or writing to an optical recording medium (18), to enable exact counting of the tracks of the optical recording medium (18) crossed by an optical scanning unit (16), it is proposed to derive a signal corresponding to the TZC signal (Tracking ZeroCross) and also a signal corresponding to the MZC signal (Mirror Zero Cross) from the output signal or the output signals (OUT1, OUT2) of a phase comparator (1) provided for tracking in accordance with the so-called differential phase detection method.

Abstract: A track seeking and track locking method in an optical storage device capable of computing protection intervals such that any state transition of the TEZC signal and the RFZC signal within the computed protection interval is prohibited. The method is also capable of preventing the interference of the TEZC and the RFZC signal due to glitches in the TE signal and the RFRP signal, thus reducing track errors and speed computational errors.

Abstract: The present invention relates to a recording and/or reproduction apparatus and a program suitable for use to record or reproduce data onto or from an optical disk having two recording layers on one side thereof.

Abstract: A servo system with a multi-track seek algorithm is presented. The multi-track seek algorithm detects zero crossings in a tracking error signal, counts the number of zero crossings to form a count, and calculates a reference velocity from the count. The algorithm also determines a time period between successive zero crossings, calculates a velocity from the time period, calculates a difference signal between the reference velocity and the velocity, and adjusts the control signal so that the velocity follows the reference velocity. The reference velocity can follow a velocity profile with acceleration portions, coasting portions, and deceleration portions which move an optical pick-up unit from a starting position to a target position.

Abstract: A control system for controlling tracking and seeking in an optical disc drive for optical media with a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The control system determines whether an optical pickup unit is over the premastered or the writeable areas of the optical media by measuring peak to peak amplitude of a tracking error signal. Gains and calibration values are selected based on whether an optical pickup unit is over the premastered or the writeable areas of the optical media. Reading from and writing to the optical media is disabled while jumping tracks. Control of jumping tracks on the optical media includes controlling: jumping a single track on the optical media; jumping a specified number of tracks every specified number of revolutions of the optical media; auto jumpbacks, and jumping in forward or reverse directions.

Abstract: Provided are a method and apparatus for canceling noise from a track cross signal, a method for controlling an optical disc drive, an optical disc drive, and an optical disc reproducing apparatus. The method for removing noise from a track cross signal includes (a) removing noise from the track cross signal by binarizing the track cross signal with reference to hysteresis set values that are determined according to a command speed for a tracking actuator; and (b) removing glitch noise from the binarized track cross signal based on a predetermined time value. Accordingly, it is possible to effective remove noise to obtain information regarding the precise speed and position of a desired track.

Abstract: Information recording area of an optical disk is divided radially into a plurality of recording areas with a boundary area interposed therebetween. The boundary area is formed as either a high-reflection area that presents a higher reflection light level than the divided recording areas or a low-reflection area that presents a lower reflection light level than the divided recording areas. When an instruction is given to move an optical head from a current point to the target point over the optical disk, a seek operation is performed up to the start point of one of the divided recording areas that contains the target point, while detecting, on the basis of a variation in the reflection light level, the boundary area located between another one of the divided recording areas that contains the current point and the divided recording area containing the target point.

Abstract: A zone where a head is positioned is determined in a track to be one of zones 1 to 4 according to a combination of the polarities of phase-A and phase-B detection outputs having different phases, and the positional deviation of the head from the current position to the center of the target track is obtained from the phase-B detection output in the zone. The phase-B detection output is provided with a dead zone corresponding to a range where both detection outputs have a phase-difference error. Therefore, even if the phase difference has an error, the positional deviation of the head is accurately calculated.

Abstract: A method and apparatus for suspending the operation of a rotating optical media player that uses simplified and efficient logic circuitry is described. When an operator initiates a pause operation, for example, by pressing a pause key, the current location of an optical pickup (e.g., a value of the current track ID) is stored. Then, a tracking servo loop is opened and a near zero offset is provided to the input of the tracking actuator. The condition of the optical disk system is then maintained in a “wait” state until the operator decides to end the pause process by selecting an alternate operation, such as “Play”, “Search”, or some other functions. When an alternate operation is received, the tracking servo loop is closed. The system then enters a search mode to reposition the optical head to the position indicated by the track ID, which was previously saved. Finally, the selected function command is activated.

Abstract: In an optical pickup direction detection unit, a detector group receives return light from an optical disc and outputs a light detection electric signal, a push-pull signal generator generates a push-pull signal, and a land prepit signal generator generates a land prepit signal. Further, a direction determiner detects a direction detection signal based on a tracking error signal and the land prepit signal.

Abstract: A tilt servo control apparatus has a tilt error correcting device for correcting a tilt error caused by a tilt angle defined between a normal at an irradiating position of a laser beam irradiated onto a recording surface of an optical recording medium and an optical axis of the laser beam. The tilt error correcting device is driven based on an intensity of the reflected light of the laser beam irradiated onto the recording surface. The apparatus provides a control to hold a drive value of the tilt error correcting device to a predetermined value in response to a track jump command for changing the irradiating position of the laser beam from the first irradiating position to the second irradiating position that is away therefrom by a distance corresponding to a predetermined number of tracks.

Abstract: A tracking error signal compensation device for removing an offset of a tracking error signal to be used for a tracking servo control includes: a low pass filter that extracts a direct current component and a low frequency component whose frequency is lower than a reference frequency from the tracking error signal, and generates a detection signal including the extracted direct current component and the extracted low frequency component; a determination device that determines whether or not a frequency of the tracking error signal is lower than a reference frequency; a holding device that generates a hold signal by holding the detection signal generated by the low pass filter, when the determination device determines that the frequency of the tracking error signal is lower than the reference signal; a detection device that detects the offset of the tracking error signal by using the detection signal and the hold signal; and a removing device that removes the offset detected by the detection device from the tr

Abstract: A focus jump moves a focus position of a light beam in a direction perpendicular to the storage medium to the focus position corresponding to a target recording layer so that the light beam is irradiated on the target recording layer.

Abstract: There is provided a track jump control device and method for an optical disc drive. A track jump control device of the present invention for jumping an optical spot from one track to another track in an optical disc drive, comprising an optical spot position command generator for generating predetermined optical spot position command data to designate the position of an optical spot every predetermined sampling period by commencing operation in response to a track jump command provided from an external source and for generating switching control polarity data for switching control, an adder for subtracting tracking error data from the optical spot position command data; and a switching unit for generating the optical spot position command data with a polarity which is left intact or reversed in response to the switching control polarity data.

Abstract: An optical disk apparatus of the present invention measures a surface deflection component (shape of surface deflection) from a low-pass component of a compensating filter in a surface deflection measuring part provided in a DSP. Furthermore, the optical disk apparatus calculates timing at which a positional change in a surface deflection component in time required for focus jumping is a predetermined value or less in a timing calculating part, and starts focus jumping at the timing. Because of this, stable focus jumping is made possible.

Abstract: When controlling a search for a target track on an optical disk having tracks on which data are recorded, the track-search control apparatus determines whether or not the optical disk is a DVD-RW disk. Then the apparatus calculates the number of tracks between the position of the currently detected track and the position of the target track, and calculates the number of correction tracks with which to correct the calculated number of tracks when the optical disk is determined to be a DVD-RW disk. Further, the apparatus executes the search for the target track based on the calculated corrected number of tracks.

Abstract: Disclosed is a method for controlling track jumps of an optical pickup in gaining high-speed access to a target track freeing from any effects of disturbances, in which time intervals of a TZC (tracking zero cross) signal are measured continuously for comparison between a target time and a measured time required for a track jump by the optical pickup. The difference in time is computed as an error, and a control signal with a voltage or a pulse width reflecting the magnitude of the error is output to an actuator of the optical pickup. In controlling the driving speed of the actuator, the comparison between target and measured times takes into account not only a time difference regarding the preceding track but also time differences with respect to a number of the previous track jumps.

Abstract: An apparatus to remove periodic disturbances in a recording medium having large eccentricity and deflection mass includes an actuator to change a position of a pickup in response to a combination of first and second compensation signals, an error detector to detect an error between positions actuator and the recording medium, a first compensator to receive the detected error and to output the first compensation signal that the actuator uses to actuate the pickup along the recording medium in upper and lower directions, and right and left directions; and a second compensator to output the second compensation signal from which the disturbance has been removed, to combine the compensated error and previous first and second compensation signals, and to filter the combined result at a predetermined bandwidth.

Abstract: The disclosed invention provides a tracking method of an optical storage. When proceeding with tracking, the optical pickup head can be moved constantly and the TE signal can be detected. Then differentiation of the TE signal is obtained. If the differentiation is less than 0, then the TE signal is masked; otherwise, the TE signal is not masked. Therefore, the TE Hysteresis signal can be determined by the TE signal and its differentiation. The TE Hysteresis signal of 0 represents that the laser beam is in the Pit, and then the tracking procedure is finished. Otherwise, the aforementioned steps are repeated until the end of the tracking procedure.

Abstract: A tracking error signal compensation device for removing an offset of a tracking error signal to be used for a tracking servo control includes: a low pass filter that extracts a direct current component and a low frequency component whose frequency is lower than a reference frequency from the tracking error signal, and generates a detection signal including the extracted direct current component and the extracted low frequency component; a determination device that determines whether or not a frequency of the tracking error signal is lower than a reference frequency; a holding device that generates a hold signal by holding the detection signal generated by the low pass filter, when the determination device determines that the frequency of the tracking error signal is lower than the reference signal; a detection device that detects the offset of the tracking error signal by using the detection signal and the hold signal; and a removing device that removes the offset detected by the detection device from the tr

Abstract: The invention provides a method of adjusting a tracking location in an optical storage device. The method is illustrated as follows. Firstly, the optical pickup head reaches the first tracking location according to a tracking error (TE) signal. Secondly, the optical pickup head is finely moved to an adjusted tracking location where the value of the amplitude of RFRP signal is maximum. The method can avoid wrong tracking location by simply based on the TE signal, then enable the optical pickup head to reach the correct track center and improve the quality of data reading.

Abstract: A method and apparatus provide positive lens position control when reading information from a disk storing data using a first and a second encoding format. When reading the data encoded in the second encoding format, the lens is maintained in a substantially stationary radial position with respect to the disk. When the data encoded in the second encoding format has an error, the lens position is changed to find a better position for reading the data.

Abstract: An apparatus for driving an optical pickup for a tracking servo control. The apparatus includes an emitting device disposed in the optical pickup for emitting a main beam to a first position on an information track of a recording medium and emitting at least two subsidiary beams to a second position and a third position on the information track of the recording medium, respectively. The positions of the main beam and the subsidiary beams are determined appropriately for a three beam method.

Abstract: A positioning control system for a disk drive can reduce static friction of the sliding type actuator to be a cause of degradation of low order spindle rotation synchronization run-out.

Abstract: An optical disk apparatus for recording and reproducing data corresponding to a track length. The track length is obtained by subtracting a total length of an m (m: natural number) number of sectors from the distance by which a track is moved when a disk is rotated an n (n: natural number) number of times.

Abstract: A plurality of periodical signals are generated as the moving body moves. The periodical signals are given respective fundamental values. The fundamental value of one of the periodical signals that has a maximum value is detected sequentially. An extension value is generated in such a manner as to be incremented or decremented when the detected fundamental value changes from one unit repetition range to another. Position detection information of the moving body is constructed as a combination of the detected fundamental value and the extension value. The position detection information is stored.

Abstract: An optical disc drive equipped with a TLN signal generating apparatus is disclosed. The TLN signal generating apparatus includes a TLN signal generating circuit for generating a TLN signal (track loss signal) based on signals obtained from an optical pick-up; a digitizing circuit for digitizing the TLN signal by comparing it with a reference level; and a correction circuit for correcting the TLN signal so that it is accurately digitized by the digitizing circuit irrespective of an offset component which is a direct current component contained in the TLN signal.

Abstract: A bandwidth control circuit and method for track-crossing signals used in an optical storage drive is used to generate a second track-crossing signal according to a first track-crossing signal transmitted from an pick-up device of the optical storage drive. The bandwidth control circuit has a first and a second low pass filters for filtering noise of the first track-crossing signal, and a track-crossing velocity calculation device for calculating a frequency of the second track-crossing signal. When the frequency of the second track-crossing signal is higher than a predetermined value, the first low pass filter is used to filter the noise of the first track-crossing signal. Otherwise, the second low pass filter is used to filter the noise of the first track-crossing signal. The method dynamically switches the low pass filters according to the frequencies of the track-crossing signals.

Abstract: The disk player is capable of preventing a shift of an object lens in an optical pickup and a poor action caused by the shift. In the disk player, a first servo mechanism drives a motor, which moves an optical pickup in a radial direction of a disk. A second servo mechanism moves an object lens in a radial direction in the optical pickup so as to trace tracks of the disk. A control unit controls the first and second servo mechanisms so as to move the optical pickup from a current track to an object track. The control unit moves the optical pickup to the object track by the steps of: driving the motor without driving the second servo mechanism so as to move the optical pickup to a track near the object track; driving the second servo mechanism after the optical pickup reaches near the object track; stopping the second servo mechanism; and driving the first servo mechanism and the second servo mechanism after the laps of a prescribed time so as to move the optical pickup to the object track.