Abstract: A circuit for controlling the moving of a pickup (track jump) between tracks of a recording medium, such as a CD-ROM. The circuit includes a first circuit which generate a pulse signal corresponding to changing points of a track jump signal and an off track signal. A second circuit generates a signal for controlling the moving speed or deceleration of the pickup, as it approaches a target track, in accordance with the pulse signal.

Abstract: A method of controlling a side push-pull (SPP) balance in a dual push-pull (DPP) type tracking servo employing both a main push-pull (MPP) balance and the SPP balance includes rotating a disc without performing a tracking servo, periodically shifting a pickup from a track center to the right and left by a first distance, obtaining an SPP signal and low-pass filtering the SPP signal to obtain a DC component, and adjusting an offset of the SPP signal so that the DC component of the SPP signal is 0. Since the pickup is forcibly and periodically shifted from the track center to the right and left by the predetermined distance during an SPP balance control, the SPP balance control can be effectively performed even on a disc having little eccentricity.

Abstract: A notch filter that filters a focus error signal during a multi-track seek operation is presented. The notch filter has a center frequency that relates to the seek reference velocity of a multi-rack seek algorithm. During the multi-track seek operation, a focus control signal is calculated from the filtered focus error signal from the notch filter.

Abstract: A seek control method carries out a seek to a target position on a recording medium by moving a light beam spot which is irradiated on the recording medium. The recording medium has a first region in which information recording is made as variations in optical or magneto-optical properties and a second region in which information recording is made as variations in geometrical configuration, and the first and second regions are provided in different areas on a recording surface of the recording medium. The seek control method includes the step of carrying out a control so that a seek operation from a seek start position within the first region to a seek target position within the second region and a seek operation from a seek start position within the second region to a seek target position within the first region differ.

Abstract: A tracking control method measures an optimum offset by measuring a light beam irradiation state of a light beam while offsetting a tracking target position of the light beam on a recording medium so that an optimum light beam irradiation state is obtained at the tracking target position, and carries out a tracking control by setting the measured optimum offset.

Abstract: The present invention relates to an optical disk apparatus which performs information recording or reproduction into/from an optical disk, and provides an optical disk apparatus which makes the amount of optical pickup movement performed before adjustment of a track error signal suited and enables reduction of a start-up time.

Abstract: A fast-acting method of regenerating track crossing signals for track searches across unrecorded areas on read/write optical discs is provided. This is accomplished by comparing the in-phase and quadrature-phase track crossing signals generated by the optical pickup head when a track search is being performed. A blank signal is generated when no quadrature-phase signal transition occurs between two successive in-phase signal transitions. Fake quadrature-phase signals are continuously generated. Upon occurrence of a blank indicating signal, the fake quadrature-phase signals are immediately supplied to the track crossing counter mechanism in place of the missing quadrature-phase signals. As a result, there is no loss of track count.

Abstract: A method for detecting the speed of a sledge motor in an optical storage device. In response to a track jumping command, a tracking servo output signal is expanded onto an orthogonal space to obtain simulation parameters corresponding to the tracking servo output signal. A pseudo-tracking servo output signal is generated according to the simulation parameters of the tracking servo output signal. Then, the pseudo-tracking servo output signal is used to compute the speed of the sledge motor.

Abstract: Method and device to update a data count in a data transfer operation in which a data counter generates an intermediate count value in accordance with a first amount of data to be transferred to a storage media; and an augmenter augments the intermediate count value by a specified count value in accordance with data to be transferred to the storage media in addition to the first amount of data, wherein the updated count value is loaded into the data counter such that the intermediate count value becomes equal to the updated count value during the data transfer operation.

Abstract: A servo system with a multi-track seek algorithm with a zero crossing detector is presented. The zero crossing detector indicates when the tracking error signal crosses zero. In some embodiments, a delay is executed between adjacent detections of zero crossings in the tracking error signal, for example half a cycle. In some embodiments, a zero crossing is detected when the tracking error signal passes through a range around zero, the range having a positive value above zero and a negative value below zero.

Abstract: An optical disc apparatus corrects the tilting of the optical disc with a high accuracy using first and second tracking error signals. A first tracking error signal, which is an output of subtractor (125), obtained by the push-pull method is corrected by detecting a second tracking error signal. The second tracking error signal is obtained by using the difference of amplitude of first and second signals, which are outputs of adder (130). The first signal is obtained when the light beam passes over a first pit sequence formed in a position offset in one direction orthogonal to the track of disc (100). The second signal is obtained when the light beam passes over a second pit sequence formed in a position offset in the other direction orthogonal to the track.

Abstract: A head load algorithm for an optical disk drive is presented. On startup, the optical media can be spun up. Then an optical pick-up unit can be positioned at an extreme position, for example at the inner diameter, and focus can be closed. The optical pick-up unit then can be incrementally moved away from the extreme position while the tracking error signal is monitored to locate an area of the optical media with tracks. Once the area is located, a tracking servo system can close on one of the tracks.

Abstract: A servo system with a multi-track seek algorithm with an track zero crossing period integrity test is presented. Zero crossing periods for subsequent cycles can be determined from a tracking error signal. If the zero crossing period for a first cycle differs substantially from the zero crossing period for a second cycle, then an error can be indicated. In some embodiments, the first cycle and the second cycle are subsequent cycles. In some embodiments, the zero crossing period in the second cycle can be between half and twice the zero crossing period in the first cycle. In some embodiments, other ranges are utilized. For example, in some embodiments the zero crossing period in the second cycle can be between one quarter and four times the zero crossing period in the first cycle.

Abstract: A tracking and servo system with a one-track jump is disclosed. The one track jump algorithm holds a control signal from the tracking servo system. The one track jump algorithm adds an acceleration control signal to the held control signal for a first period of time, delays for a second period of time, and adds a deceleration control signal to the held control signal for a third period of time. The algorithm then frees the control signal to close tracking on a new track separated by one track from the starting track.

Abstract: A close tracking algorithm for a tracking servo system is disclosed. The track crossing rate of an optical pick-up unit positioned over an optical media is determined. When the track crossing rate is below a threshold value, then a tracking servo algorithm is enabled. The tracking servo algorithm provides control signals to control an actuator arm that controls the position of the optical pick-up unit over the tracks of the optical media. In some embodiments, the track crossing rate can be determined by monitoring the zero crossings of a tracking error signal derived from optical signals measured in the optical pick-up unit.

Abstract: An optical pickup apparatus capable of reading information from recording media of different read wavelengths, includes a light-emitter having a first light source for emitting a first laser beam integrated with a second light source for emitting a second laser beam of a different wavelength from that of the first laser beam. The optical pickup apparatus includes a photodetector for receiving a beam reflected by each of the recording media and an optical system having a plurality of optical elements which form an optical path to guide the first and second laser beams to the recording media and which form an optical path for guiding the reflected beam to the photodetector and through which the first and second laser beams pass.

Abstract: A disk apparatus includes a DSP (digital signal processor), and the DSP controls respective circuit components under instructions of a MCU. During a track jump, a DSP core detects a zero-cross cycle of a TE (Tracking Error) signal just before. If a detected zero-cross cycle is delayed than a target value, the DPS core applies an acceleration pulse of a first predetermined level to a driver, and if the zero-cross cycle is faster than the target value, the DPS core applies a deceleration pulse of a second predetermined level to the driver, whereby an objective lens can be controlled to move at approximately constant speed between adjacent tracks. However, if the zero-cross cycle is considerably delayed than the target value, the DSP core forestalls a reverse rotation of a moving direction of the objective lens against the disk by greatly accelerating the objective lens. Therefore, the number of tracks to have been jumped is not to be counted erroneously.

Abstract: A track jump apparatus for making an actuator jump in order to move a spot position of a laser beam emitted through an objective lens of the actuator from a current position to an object position corresponding to a desired recording track on a recording medium.

Abstract: A beam irradiation apparatus includes a beam generation source (41) for generating at least either of an optical beam, an electron beam and an ion beam, and a focusing lens (48) for focusing a beam emitted from the beam generation source (41). The beam irradiation apparatus includes at least first and second focus control mechanisms (71) and (72) each controlling a focus position of the beam with respect to the same lens system forming the focusing lens, so as to focus the beam onto an irradiation object (40) by using the focusing lens (48), whereby it possible to obtain a minute beam spot and to conduct a reliable, and stable focus control.

Abstract: Even if an assumed value of a track pitch and an actual value thereof are different from each other, an optical pickup (2) can be positioned at a target position at high speed, which can realize higher-speed access.

Abstract: Disclosed is an information recording/reproducing device using an upright disk-like recording medium contained in a cartridge, wherein an objective lens is stably moved in the tracking direction with less undesirable displacement and also the entire optical head portion including the objective lens is prevented from being undesirably moved. The device includes a disk mounting portion on which a disk contained in a cartridge is mounted with a recording surface portion located within a vertical plane, an optical head portion having an objective lens opposed to the recording surface portion of the disk, and an optical head drive portion, a tracking control portion, and a cartridge housing portion for housing and supporting the cartridge containing the disk when the disk is mounted on the disk mounting portion.

Abstract: An optical disk unit that directs a light beam onto a pregroove on an optical disk and generates a tracking error signal for tracking control based on a detection signal generated from a reflection of the light beam, the optical disk unit including a recording offset generator that acquires a differential between a tracking error component generated from a detection signal from the reflection of the light beam at a write power level and a tracking error component generated from a detection signal from the reflection of the light beam at a read power level and adds the differential to the tracking error signal at recording.

Abstract: An optical disk device starts movement of a thread in a track-on state, and releases the track-on state when the thread moves by a certain amount, and gives a driving kick signal to an actuator. The movement of the thread and actuator can be placed in sufficiently good balance so that failure of track jump is prevented, thereby improving the reliability of the device body and suppressing the cost-up of the device body.

Abstract: In order to correct the change in the offset and amplitude of a tracking error signal because of the change in the position of an object lens from the center of an optical pickup, the offset amount and amplitude value of the tracking error signal with respect to the displacement amount of the object lens from the center of the optical pickup are checked beforehand, and the displacement amount of the object lens is estimated on the basis of a tracking correction signal by using an object lens displacement observer.

Abstract: A compact disc player includes an optical pickup supported by a carriage and a microprocessor for controlling the movement of a coarse actuator and a fine actuator. The coarse actuator controls the movement of the carriage and maintains its position when power is interrupted to the coarse actuator. The fine actuator is disposed between the carriage and the pickup and provides fine movement for the pickup when power is supplied to the actuator. The fine actuator moves the pickup to a neutral position when power is interrupted. A resume function is provided that restores the position of the pickup after a power interruption to its position before the interruption. A value indicative of the position of the pickup relative to the carriage is stored in memory. When power is restored to the disc player, the value is read from memory. The disc control microprocessor directs incremental movements of the fine actuator until the position of the pickup corresponds to the position represented by the stored value.

Abstract: In order to perform stable focusing jump in accordance with the wobble of a disk, an optical pickup is moved radially inward toward a central area of the disk where the amount of wobble is small. A focusing error signal in accordance with wobble is feed-forwarded during focusing jump so as to also follow the wobble during the focusing jump. Furthermore, the position of an objective lens is maintained while waiting for the signal recording surface of the disk to reach a focus position due to wobble. In addition, the rotation speed of the disk is controlled in accordance with the amount of wobble.

Abstract: A motor constant Km of a sled mechanism of an optical disc drive is to be measured. To this end, a parameter measurement device 1 for the sled mechanism includes an oscilloscope 8 for detecting the back-electromotive force Eb of a sled motor 5, a laser Doppler meter 7 for detecting the movement velocity v0 of the pickup 4 and a computer 9. The computer calculates an equation Eb=KmRmv0, where Rm is the resistance of a motor, to find the motor constant Km.

Abstract: A position controller of an optical system comprising an optical system for forming a near-field with an optical recording medium and focusing converged light to the optical recording medium; an actuator for moving the optical system in a focal direction perpendicularly intersecting a recording surface of the optical recording medium; and a control circuit for controlling the actuator so as to shorten the distance between the optical system and the optical recording medium from outside to inside the range where the near-field is formed and further maintain it inside the range; a position control method of an optical system; and a recording/reproducing apparatus and driving method thereof.

Abstract: An optical recording/reproducing apparatus for determining a direction in which an optical pick-up moves, and detecting a track cross signal. The track cross signal is useful as a basis of determining tracking pull-in after searching a track. In the present track cross signal detecting method, the track cross signal is obtained by binarizing the envelope of an RF signal RF0 obtained by subtracting some light receiving signals generated by some light receiving devices in the radial direction from other light receiving signals generated by other light receiving devices in the radial direction. The light receiving signals originate from a photodetector, divided into two or more sections in the radial direction. The track cross signal detecting method is especially useful for generating the track cross signal when the track pitch is smaller than the size of an optical spot, the signal being less affected by crosstalk caused by an adjacent track.

Abstract: Disclosed is an apparatus for controlling eccentricity in a photo-record player and a control method thereof. A relative eccentric quantity is found from a TE signal (or, tracking driving voltage) induced per one revolution of disc ‘on track’and an eccentricity phase to be controlled is found from a periodicity of TE (or, tracking driving voltage) per one revolution of disc. A suitable compensating value for the relation between the found eccentricity quantity and phase is generated by taking FG representing a period of revolution as a reference. Then, the compensating value is used for an eccentricity control ‘on track’, or driving the tracking actuator on ‘seek’. Therefore, the present invention reduces a seek location error due to the eccentricity on ‘seek’, thereby enabling to increase a seek performance.

Abstract: A feed velocity control apparatus of a disc player which can execute a stable velocity control of an information reading point by reducing influences by scratches formed on the recording surface of a recording disc, noises, or the like. A velocity signal corresponding to a transporting velocity of the information reading point at the present time point for the recording disc is obtained based on a tracking error signal. At the time of the track jumping operation, when the velocity signal lies within a predetermined velocity range, the information reading point is transferred in accordance with a velocity error signal corresponding to a difference between the velocity signal and a predetermined velocity. When the velocity signal is out of the predetermined velocity range, the information reading point is transferred in accordance with a low band component of the velocity error signal in place of the velocity error signal.

Abstract: An optical disc device with high reliability, which is capable of performing a stable track jumping, is provided. In the optical disc device, a space (time interval) between an address part and the next address part in the address space measuring part 116 inside the DSP 111 is measured, and when the reproduction speed detected in the reproduction speed detection part 117 based on the measuring result is faster than a predetermined reproduction speed, an application timing of an accelerating pulse is switched in the accelerating/decelerating pulse generator 113 such that the application timing of an accelerating pulse or a decelerating pulse is matched with a transit timing in the address part.

Abstract: In a track-following method in a DVD-RAM disc, CAPA detection is avoided during the track-following process, and a track-following operation is stably made from a high-speed state using adaptive deceleration pulses. In order to avoid CAPA detection during the track-following process, a CAPA is detected from a tracking error signal using a high-pass filter, and the track-following start timing is set within 0.4 ms after the detection of the CAPA. The pulse width of the adaptive deceleration pulses to a lens actuator is variable so that the tracking error signal follows a standard tracking error signal. The zero-crossing point of the tracking error signal after the detection of the CAPA is set as the track-following start timing, and tracking-servo is started after an adaptive brake process for varying the deceleration pulse width based on the difference between the tracking error signal and standard tracking error (TE) signal.

Abstract: Disclosed is a seek control method in an optical storage device, of seek-moving a light beam of an optical head from a certain track on an optical storage medium to a desired track. This seek control method comprises a step of calculating a target position, a step of detecting a present position from a track error signal indicating a relative position between the light beam and the track, a step of calculating such a feedback control quantity as to zeroize an error between the target position and the present position and a step of controlling a moving mechanism for moving the light beam in accordance with the feedback control quantity.

Abstract: A defined level comparator compares a track error signal with each of a predetermined upper limit level and a predetermined lower limit level so as to generate two comparison signals. A logic unit ANDs two comparison signals so as to obtain a track pull-in enabling signal. A header component removal arithmetic unit removes a header component from the track pull-in enabling signal in accordance with a header area signal. A track polarity inverter outputs a land/groove detection signal in which a polarity of a signal level is inverted every timing at which a signal level of the track pull-in enabling signal is in a track pull-in enabling state. A track polarity correcting and determining unit compares a polarity signal held by a sampling holder with the land/groove detection signal in the header area.

Abstract: In a disk drive device, a CPU of a CD-R drive starts acceleration from low rotational driving towards a target rotational speed in a condition in which a tracking servo is in an OFF condition and simultaneously starts counting a number of tracking errors prior to performing recording or reproduction. Upon comparison of the number of counts and a specified threshold for determining vibration, in case the number of counts has exceeded the threshold, the tracking servo are turned ON for performing recording or reproduction at a rotational speed that is lower than the target rotational speed.

Abstract: An apparatus for and a method of detecting a defocus error signal. First, second and third light receiving regions of a photodetector are arranged in a radial direction of a recording medium to independently perform photoelectric conversion with respect to incident light which is reflected/diffracted by the recording medium. A subtractor subtracts a sum signal of detection signals from the first and third light receiving regions and a detection signal of the second light receiving region to output a defocus error signal, to detect defocus and/or a change in thickness of the recording medium. The defocus error signal and a push-pull tracking error signal are compared in a state in which a predetermined amount of defocus is applied to a light spot to detect a seek direction of the recording medium having a land/groove structure.

Abstract: An optical pickup for reading information from a recording medium comprises a light illuminating portion for illuminating a plurality of light beams having different wavefronts onto a recording surface of the recording medium to create a plurality of light spots including a first light spot and a second light spot. The first and second light spots at least partially overlap with each other. A detector receives light beams reflected by the recording medium. The detector has a first light-receiving surface for receiving reflected light of the first light spot and a second light-receiving surface for receiving reflected light of the second light spot.

Abstract: A circuit for detecting the mirror signal from the output signal of an RF (radio frequency) in an optical disk drive, includes a first peak hold circuit for holding the peak value of the output signal of the RF amplifier to provide a first peak value, a first bottom hold circuit for holding the bottom value of the output signal of the RF amplifier to provide a first bottom value, a differential amplifier for amplifying the difference between the first and second peak values, a second peak hold circuit for holding the peak value of the output signal of the differential amplifier to provide a second peak value, a second bottom hold circuit for holding the bottom value of the output signal of the differential amplifier to provide a second bottom value, a centered value extractor for processing the second peak and bottom values to extract the centered value of the output signal of the RF amplifier, a comparator for comparing the centered value with the output signal of the differential amplifier to generate the m

Abstract: An optical information recording and playback apparatus for recording and playing back an optical information recording medium having a transparent protective layer comprises a tilt detection device and an off-track adding device, and includes means for determining an optimum direction in which the center of a light spot is to be displaced from the centerline of an information track on the optical information recording medium to compensate for the tilting of the optical information recording medium relative to the light beam, means for setting the amount of displacement as fixed values, and means for splitting the optical information recording medium into a number of areas and for activating a tilt detection function each time switching is made from one area to another during recording or playback.

Abstract: A disk reading apparatus includes a binarizing unit 5 for binarizing a tracking error signal 21 with a hysteresis width and for generating a track count signal 22, a jump unit 8 for causing track-jump on the basis of the track count signal 22, a malfunction detecting unit 9 for transmitting a malfunction signal 24 when level inversion occurs to the track count signal 22 while follow of the track is being implemented, and a control unit 15 for widening the hysteresis width when the pickup 1 is caused to follow the track, and for narrowing the hysteresis width when the pickup 1 is caused to track-jump.

Abstract: The present invention provides an information storage apparatus that generates a tracking error signal based on a detection signal, and performs various control operations based on the tracking error signal. When the operation mode is a seek operation mode, the information storage apparatus generates a tracking error signal by holding the peak value of the detection signal. When the operation mode is a tracking operation mode, the information storage apparatus generates a tracking error signal directly from the detection signal. With this information storage apparatus, stable control operations can be performed, regardless of changes of conditions.

Abstract: In a seek operation, in which a head is moved to a target track, the detection output of a head-position detection unit is integrated in each track. Each integrated value is a positive or negative value proportional to an offset given to a center value obtained from the maximal value and the minimal value of the detection output. The center value is compensated for by a compensation value obtained by multiplying the integrated value by a coefficient. As a result, the offset is reduced and a highly precise positional detection is allowed.

Abstract: A track-jump controlling apparatus that controls track-jump operations over disks complying with various DVD data formats includes a quad photodetector having quadrants B1 to B4, a DPDTE signal generator 13 for generating DPD tracking error signals, a push-pull signal generator 14 for generating push-pull signals, and a TZC signal generator 15 having a selector switch 15a for switching the path between the DPDTE signals and the push-pull signals and a comparator 15b for generating TZC signals. In order to prevent failure to obtain proper TZC signals in a seek operation with respect to a DVD-RW, etc. involving passage over an unrecorded area during reproduction, f or example, the selector switch 15a is switched to the push-pull signal side to prevent track counting failure associated with the track-jump operation with respect to the DVD-RW.

Abstract: A servo method for an optical recording medium for detecting a tracking error signal by a push-pull method is disclosed. Before a servo operation, an amount of DC offset per track is obtained as an object lens of an optical pickup is moved in a specified direction, and a tracking servo is performed by compensating for a tracking error signal based on an initial amount of DC offset obtained by multiplying the amount of DC offset generated per track by the number of jumped tracks when the object lens is shifted. After movement of a sled by driving a sled servo, a sled servo is performed by compensating for the tracking error signal based on a value obtained by subtracting an amount of sled movement from the initial amount of DC offset, and thus an optical beam can always follow a track center even when the DC offset is generated in the tracking error signal.

Abstract: A data reading apparatus and a data reading method are disclosed which are structured to efficiently read data from a recording medium so as to improve data processing speed. A reading-order control circuit obtains first total jump time which is taken when data is read from an optical disc in an order as first, second, third and fourth files and second total jump time which is taken when data is read in an order as first, third, second and fourth files. The reading-order control circuit determines whether or not the first total jump time is longer than the second total jump time. If the reading-order control circuit determines that the first total jump time is longer than the second total jump time, the reading-order control circuit controls an optical head to read data from the optical disc in the order as the first, third, second and the fourth files.

Abstract: A track-number seeking algorithm and a seeking means for the dynamic modification of the computation of track numbers in an optical storage device employs a down counter, an up counter and a microprocessor. First, a rotation number of an optical storage disk in the microprocessor, a track error zero crossing signal of the down counter and the up counter are reset, a static track seeking number of the down counter is set, and a seeking operation is performed. The seeking operation reads the rotation number and the track error zero crossing signal, computes a residual track number, and judges whether an overflow flag is to be sent. If the overflow flag is sent, then, the rotation number is added, a pulse number of a feedback signal is reset, and the next step is to judge whether the seeking operation is outward or not. If the overflow flag is not sent, the next step is to judge directly whether the seeking operation is outward or not.

Abstract: The present invention provides a track traverse signal detecting circuit which controls the level of a reference voltage by calculating a mean value of a track traverse signal, or adjusting the frequency or the phase of the track traverse signal. The track traverse signal detecting circuit further determines whether the disc is a CD or a DVD, and controls the level of the reference voltage accordingly, and then detects the accurate track traverse signal. Therefore, in case of track jump or random access, the track access operation can be performed accurately.

Abstract: Disclosed is an optical disc drive. The optical disc drive is provided with an arm member carrying an objective optical system and a light emitting system. The arm member is rotatable about an axis at one end portion thereof. On the other end portion of the arm member, the objective optical system is mounted. A detecting system is further provided for receiving light reflected by the optical disc via the objective optical system. The detecting system detects data related to an orientation of a beam spot formed by the reflected beam on its light receiving surface. Further provided is a control system which determines a current position of the arm member based on the data related to the orientation of the beam spot.

Abstract: An apparatus for use in an optical disc includes an optical disc and an optical branching unit irradiating a main light beam and a sub-light beam, wherein the sub-light beam includes a optical aberration in a direction on a track of the optical disc. The apparatus further includes a photodetector including a plurality of portions receiving and processing the main light beam and a plurality of portions receiving and processing the sub-light beam. A track error signal detector detects a track error signal from the portions receiving the main light beam. A track cross signal detector detects a track cross signal from the portions receiving the main light beam and from the portions receiving the sub-light beam. A signal processor further compares the track error signal with the track cross signal to detect the seek direction of a light spot formed on the optical disc.