Abstract: An optical disk apparatus according to the present invention is capable of reading data from an optical disk 102 which has a plurality of information recording layers, including a first information recording layer whose distance from a disk surface is relatively small and a second information recording layer whose distance from the disk surface is relatively large. This optical disk apparatus includes: a focus control section 117 for causing a converging point of the light beam to be positioned on an arbitrary information recording layer of the optical disk 102; a tracking control section 118 for causing the converging point of the light beam to be positioned on a predetermined track of the information recording layer; and a gain switching section 108 capable of changing gain characteristics of at least one of the focus control section 117 and the tracking control section 118.

Abstract: An optical disk apparatus is constructed for writing or reading information by irradiating a laser beam onto an optical disk while rotating the optical disk under a focus control of the laser beam relative to the rotated optical disk. In the optical disk apparatus, an irradiating section is operated to irradiate a laser beam onto the optical disk. A determining section determines a process pattern of the focus control by operating the irradiating section to irradiate the laser beam onto a predetermined area of the optical disk and by monitoring the laser beam reflected back from the predetermined area. A focusing section performs the focus control to regulate a spot diameter of the laser beam based on the determined process pattern during either of the writing or reading of information.

Abstract: An optical disk as disclosed herein includes, among other things, a summing module that sums a compensation signal to a predetermined signal in a servo loop. The compensation signal compensates for a periodical disturbance input into a servo system of the optical disk device in units of a rotation angle of the disk rotating module. A phase lead imparting module imparts a predetermined amount of phase lead to an output signal from an optical detector module and outputs the predetermined amount of phase lead as the compensation signal. The predetermined amount of phase lead is determined in accordance with the rotation period information. The optical disk device performs an accurate iterative learning control to provide stable servo performance. The iterative learning control is performed such that the signal having imparted an optimal amount of phase lead in accordance with the rotation period information is added to the servo loop.

Abstract: In the optical disk drawing apparatus of the present invention, an automatic adjusting area where the drawing operation is not carried out is provided in the optical disk, laser light is irradiated onto the formed automatic adjusting area so as to control the focus servo gain, so that a stable focus servo control can be carried out.

Abstract: A signal-processing device (301) for controlling a focus actuator (309) in an optical disc system (30), wherein the signal processing device (309) generates a focus actuator control signal (CS) to be supplied to the focus actuator (309). The focus actuator control signal (CS) is based on a focus error signal (FE) and a central aperture signal (CA). If the central aperture signal (CA) is equal to or above a certain threshold value the focus actuator control signal will correspond to the focus error signal (FE). However, when the central aperture signal is below the threshold value the focus actuator control signal will have a predefined level. By providing a focus actuator control signal (CS) in accordance herewith it is possible to extend the regions of the focus error signal (FE) in which the relative distance between the focus point and the data layer of the record medium (304) is not correctly represented.

Abstract: An optical disc apparatus and a focusing method for the same prevent a focusing start error of an optical pickup when using a ring-shaped lens to handle multiple wavelengths, and allow the optical pickup to start focusing at the correct starting time. To write and/or read data to and/or from an optical disc, an optical pickup in the optical disc apparatus emits a laser beam to the disc through an objective lens, and reads a reflected beam to output a read signal. The optical pickup outputs a signal based on the read reflected beam. An actuator controls the position of the objective lens so that the laser beam is focused on a surface of the disc. A focusing controller performs focusing operations on the actuator using a focus error signal generated from the signal outputted from the optical pickup. A focusing start time detector processes the read signal used to generate the focus error signal and detects when to start the focusing control of the focusing controller.

Abstract: A system and method for calibrating a recording track offset of an optical storage device accessing an optical storage medium of land/groove type. The system includes: a tracking servo loop arranged to control tracking operations of an optical head of the optical storage device; a track offset control loop arranged to control the recording track offset for the tracking servo loop; a controller arranged to enable a latest value of the recording track offset to be a readout value for utilization in a recording process performed later; and a comparator arranged to compare a recording length with a threshold value and generate a flag to represent whether the recording length is a long recording length, wherein the latest value is derived from the track offset control loop.

Abstract: An optical disk drive includes focusing means, moving means for moving the focusing means in a direction perpendicular to a track direction, light detection means having a first light acceptance section accepting a light beam reflected by one information recording layer and a second light acceptance section accepting stray light reflected by another information recording layer, tracking error signal generating means for generating and correcting the tracking error signal using an output of the second light acceptance section, and tracking control means, wherein the second light acceptance section is composed of a disk inner area and a disk outer area, and where the stray light is accepted without accepting the light beam, and the tracking control means removes an offset caused by the stray light using a difference between the output of the disk inner area and the output of the disk outer area.

Abstract: In a tracking control method for use in an optical disk drive to read/write an optical disk, an open-loop tracking control operation of the optical disk drive is first performed according to an input tracking error signal and a predetermined periodical offset to generate a dynamic offset. Afterwards, a closed-loop tracking control operation of the optical disk drive is performed according to the input tracking error signal calibrated with the dynamic offset.

Abstract: A high-density read-only optical disc, and an optical disc apparatus and method using the same. The apparatus and method record data on a lead-in area of a high-density read-only optical disc such as a BD-ROM (Blu-ray disc ROM (Read Only Memory)) in the form of pre-pit strings associated with an HFM (High-Frequency Modulated) groove applied to a BD-RW (Blu-ray Disc Rewritable). Moreover, the apparatus and method continuously apply the same tracking servo operation to an entire area of the same high-density read-only optical disc or rewritable optical disc. Therefore, the apparatus and method can simplify an algorithm for controlling a plurality of tracking servo operations, and avoid an increased size of the optical disc apparatus.

Abstract: An automated capability is provided in which an offset correction is automatically determined and routinely updated in order to reduce or otherwise eliminate data retrieval errors that may be caused by low level distortion in optical disc data storage recording, re-recording and retrieval system. The capability is implemented through an improved offset control loop for reading information from a modulated wobble signal with which the data is recorded to an optical disc data storage medium to provide detection of an offset and correction of that offset to facilitate implementation of precise timing synchronization and/or encoded information contact in the system. The offset detector measures a wobble signal and mathematically converts detected information regarding the measured wobble signal to an offset correction by integrating the wobble signal over a specific time interval and comparing the integrated value to an expected integrated value.

Abstract: Disclosed is a TE signal polarity determining method, which includes: (a) obtaining a detection signal from an optical disc; (b) obtaining characteristics of the detection signal corresponding to different polarities of the TE signal; and (c) determining whether an original polarity of the TE signal should be changed or not according to the obtained characteristics.

Abstract: A gain setting method for setting a gain in an amplifier that amplifies signals obtained from an optical disk, which includes: a measuring step for measuring an output level of the amplifier; and a gain setting step for setting the gain as the value of the target level/output level, when the measured output level is in a range of 1/N times and N times (N is an integer of 2 or larger) with respect to the preset target level.

Abstract: An optical disk recording apparatus having (1) an optical pickup that emits laser light to illuminate a recording surface of an optical disk, receives reflected light resulting from the laser light reflected off the recording surface, and generates a light reception signal based on the thus received reflected light; (2) a laser power controller that sets a laser power setting and controls the power of the laser light emitted from the optical pickup based on the thus set laser power setting; and (3) a signal generator that, when a plurality of trial write areas provided on the recording surface of the optical disk are successively illuminated with the laser light in order to write trial write data, generates a timing notification signal that sets laser arrival timing when the laser light sequentially reaches trial write start positions of the plurality of trial write areas based on the light reception signal generated by the optical pickup.

Abstract: The gain controlling portion sets a gain of an RF amplifier to a maximum range when an activation process starts for an optical disk. The binary process condition setting portion sets an upper threshold level and a lower threshold level corresponding to 80% of upper and lower levels of the maximum range as the binary process condition for the binary process portion. A vacant part without a signal between the upper threshold level and the lower threshold level corresponds to a part of a CAPA signal. The binary signal ratio calculating portion measures a time period of a binary signal from a binary process portion that performs a binary process on the vacant part, and it calculates a binary signal ratio indicating a ratio of the time period of the binary signal to a time period corresponding to one rotation of the optical disk. The disk discriminating portion determines that the loaded optical disk is a DVD-RAM if the binary signal ratio is a value within the range of 4±1 %.

Abstract: The method for estimating recording power Pow_tilting of a tilting part of a tilting disk is shown based on a power compensation formula: Pow_comp=A*(A*K). After a focus error (FE) signal of the tilting part of the tilting disk is manipulated as a focus servo output (FOO) signal, the parameter A is derived by low-pass filtering the FOO signal. Thereafter, another parameter K is then derived from a reference lookup table by using curve fitting approach based on parameter A such that the power compensation Pow_comp could be estimated by substituting parameters A and K into the above formula. A recording power Pow_tilting of the tilting part of the tilting disk could be estimated by adding a given recording power Piwrtpwr to the power compensation Pow_comp.

Abstract: There is provided an optical disk device that performs a focus jump operation in a stable and prompt manner. The optical disk device includes an objective lens, a light-detecting element, a lens holder, a shaft member configured to penetrate a hole, a focus drive mechanism, a focus drive circuit, a tracking rotation mechanism, a tracking drive circuit, and a control circuit. The control circuit includes a drive control portion, a wobble control portion, and a switch portion. The drive control portion generates a control signal to be input to the focus drive circuit and a control signal to be input to the tracking drive circuit. The wobble control portion generates a control signal indicating that a current value should fluctuate. During a period of focus jump, the switch portion introduces into the tracking drive circuit the control signal generated by the wobble control portion.

Abstract: Provided is a focus servo process automatic selecting method. In a related art optical pickup apparatus, only one of AD and DAD is selected and used when a focus servo is performed for disk detection and a focus-on operation. According to the method, servo crosstalk values of the two focus servo processes are compared and a suitable focus servo process is automatically selected, so that an optimum focus servo is realized.

Abstract: A disc-driving apparatus has an optical pickup including an objective lens. The objective lens has an optical axis that is met on a line excluding a central axis of revolution of a disc. The apparatus has storage device that stores plural correction values obtained by detecting fluctuations in amplitude of a tracking error signal with respect to a radial direction of the disc or a quantity of de-tracking with respect to the radial direction thereof. The apparatus has control device that reads the correction value from the storage device and, when the optical pickup is operating, corrects the tracking error signal to conduct servo control based on the corrected tracking error signal.

Abstract: An optical disk device includes a optical pickup head which emits a laser beam to an optical disk and detects light reflected therefrom, a signal output unit which outputs at least a servo signal and RF signal in accordance with the detected light, a gain control unit which determines the type of the optical disk from identification information recorded thereon, and sets first and second adjusted gains for a data recorded region and data unrecorded region, when determining that the optical disk is of a type wherein a light reflectance is higher in the data recorded region than in the unrecorded region, and a gain adjustment unit including a memory storing the first and second adjusted gains, the gain adjustment unit adjusting the gain of the servo signal in the data recorded region, using the first adjusted gain, and in the data unrecorded region, using the second adjusted gain.

Abstract: An apparatus and method for controlling an optical disk device performs a disk loading and unloading operation based on at least one driving signal containing multiple pulses of different widths. The pulses are applied to control a motor to unclamp the disk relative to a spindle. Because the signal is formed from multiple pulses of different widths, the unclamping operation is performed with little or no shock forces and as a result the disk is ejected without damage and without being dislodged from the device.

Abstract: The present invention relates to an information reproducing apparatus that includes an objective lens that focuses a light beam toward a rotating optical disc medium and uses the objective lens to focus the light beam onto the optical disc medium and detect the reflected light of the light beam so as to reproduce information stored on the optical disc medium. The present invention allows measurement of surface deflection of the optical disc medium with no risk of collision between the objective lens and the optical disc medium. The objective lens is brought closer to the optical disc medium from a separate position apart from the optical disc medium and immediately moved away from the optical disc medium when the light beam is focused onto the optical disc medium.

Abstract: A multi-zone calibration system is disclosed. The multi-zone calibration system calibrates the operating parameters of an optical disk drive over a plurality of zones over an optical media. The optical media, in addition, can have writeable and premastered portions. The operating parameters can be calibrated for each of the media types in each of the zones. Additionally, the operating parameters can be calibrated for each type of operation (e.g., read or write) in each zone.

Abstract: A method of adjusting spherical aberration correction and focus offset of a light beam. A first approximate straight line is detected indicating a first relationship between the spherical aberration correction and the focus offset according to a first evaluation index indicating a quality of cross-track signal. A second approximate straight line is detected indicating a second relationship between the spherical aberration correction and the focus offset according to a second evaluation index indicating a quality of a reproduced signal. A spherical aberration correction value and a focus offset value, to be adjusted, are determined from an intersection of the first approximate straight line and the second approximate straight line.

Abstract: A focusing controller and the method thereof for an optical disk drive. The focusing controller includes a filter, a coupler and a focus compensator. The filter filters out a high-frequency component of the track error signal and derives an adjusted signal, while the coupler eliminates the adjustment signal from the focusing error signal so as to generate a coupled signal. The focus compensator generates a focus control signal used for controlling a position of the pick up head of the optical disk drive according to the coupled signal during a focusing operation.

Abstract: Detection of a wobble cycle of wobble formed at a groove of an optical disc is started. A phase locked loop time that is from reset of phase locked loop circuit until a signal read from the wobble locks is calculated. The focus balance value corresponding to the minimum phase locked loop lock time is set as the focus balance value for ADdress In Pre-groove. When ADdress In Pre-groove information being address information is read, focusing servo control is performed with the focus balance value for ADdress In Pre-groove.

Abstract: Calibration methods are provided for determining servo parameters to enhance an optical drive in reading and writing a blank optical disc. First, test data is written on the blank disc with various writing parameters. Second, the written test data is read from the optical disc with various reading parameters. A plurality of quality measures are obtained, each corresponds to a specific combination of the writing parameter and the reading parameter. An optimal writing parameter and an optimal reading parameter are determined by comparing the quality measures with respect to both the reading and writing parameters respectively.

Abstract: An optical recording medium driving apparatus supporting an optical recording medium having multiple recording layers includes head means including a focusing mechanism and a spherical aberration correction mechanism; focusing control means for driving the focusing mechanism on the basis of a reflected light to perform focusing control on each recording layer; spherical aberration correcting means for driving the spherical aberration correction mechanism on the basis of a spherical aberration correction value to correct spherical aberration; and control means for controlling the focusing control means so as to set the spherical aberration correction value given by shifting the spherical aberration correction value appropriate for the midpoint between a target layer and a first recording layer by a desired value in the spherical aberration correcting means and controlling the focusing control means so as to perform the focusing control with the spherical aberration correction value after the shift being set.

Abstract: A pickup control device includes a servo system which processes a first signal for error control read from an optical disk to generate a servo control signal. A clock signal is synchronized with the rotation of the optical disk. Two memories store a frequency component at or lower than a predetermined frequency contained in the first signal and a rotational frequency component contained in the first signal. A first adder adds data from the first memory to the first signal and a second adder, in synchronization with the clock signal, data from the memories to generate a second signal. A correction unit writes into the second memory the frequency component or the rotational frequency component and reads data and supplies data to the first adder, and reads and updates data stored in the first memory.

Abstract: A focal control adjusting method according to the present invention comprises a first step for detecting a focal error signal obtained through condensing and irradiating a light beam on a rotating recording medium, and a second step for setting a focal control gain for controlling a positional shift between a recording surface of the recording medium and the light beam based on the focal error signal detected in the first step, wherein a result obtained by multiplying the position detection signal (sub light beams) by a preset coefficient is added to the position detection signal (main light beam), and a result of the addition is detected as the focal error signal in the first step, and the coefficient is set in accordance with the focal error signal in the first step.

Abstract: In an optical disk apparatus and a disk rotation speed control method thereof, enabling to rotate a disk at high speed, with stability and certainty, irrespective of mass eccentricity thereof, detection is made on the greatest value and the smallest value on the signal after conducting a process of a band pass filter 511 on a lens error signal in a step response of a pickup, with using a wobble signal in the place of a tracking error signal and chaining an offset, when controlling the rotation speed of the apparatus by loading an optical disk therein, and thereafter, determination is made on whether the disk rotation speed be shifted to the high speed or not, upon basis of a value obtained through comparison of the maximum value (Max_spnup) and the minimum value (Min_spnup) obtained with the greatest value (Max_step) and said smallest value (Min_step) memorized, when shifting the disk rotation to the high speed.

Abstract: An optical pickup irradiates laser light upon a track of an optical disk and receives light reflected therefrom. A tracking actuator shifts an objective lens of this optical pickup in a tracking direction. A tracking error signal detection circuit outputs a tracking error signal based upon the reflected light received by the optical pickup. A phase compensation circuit generates a tracking drive signal based upon the tracking error signal, and outputs this tracking drive signal to the tracking actuator. A balance compensation value calculation circuit calculates a balance compensation value for the tracking error signal according to the tracking drive signal outputted by the phase compensation circuit. And a balance compensation circuit adds this balance compensation value to the tracking error signal detected by the tracking error signal detection circuit, and inputs this compensated value to the phase compensation circuit.

Abstract: An apparatus for obtaining a push-pull signal is disclosed. The apparatus includes: a first amplifier coupled to a first fluctuating signal for utilizing a first gain value to amplify the first fluctuating signal and then outputting a first amplified fluctuating signal; a second amplifier coupled to a second fluctuating signal for utilizing a second gain value to amplify the second fluctuating signal and then outputting a second amplified fluctuating signal; a subtractor electrically connected to the first and second amplifiers for subtracting the second amplified fluctuating signal from the first amplified fluctuating signal to generate the push-pull signal; and a level decision unit electrically connected to the first and second amplifiers for controlling the amplitudes of signals amplified by the first and second amplifiers when the optical disc drive is switched from a first operating mode to a second operating mode.

Abstract: A label side of a light-scribe optical disc includes a control feature zone recording therein reference information of the optical disc and a label zone to be marked based on the reference information. An optical head is moved in the label zone to determine a first FE gain and a first sub-beam addition (SBAD) signal by way of focusing servo technology. The optical head is further moved in the control feature zone to determine a second SBAD Signal. The first and second SBAD signals are operated to obtain a ratio. The ratio is used with the first FE gain to estimate a second FE gain for accessing to the control feature zone.

Abstract: An apparatus for detecting the wobble carrier frequency of an optical disk is disclosed. The apparatus comprises an offset canceller, a binary conversion module, an adjustable band pass filter, and a frequency detection module. The offset canceller cancels the direct current offset of a first wobble signal to obtain a second wobble signal. The binary conversion module converts the second wobble signal to a binary data stream. The adjustable band pass filter passes only an adjustable frequency range of the binary data stream to generate a filtered signal, wherein the center frequency of the adjustable frequency range is sequentially adjusted. The frequency detection module then determines maximum amplitude of the filtered signal, and determines the center frequency of the adjustable frequency range according to which the filtered signal with the maximum amplitude is generated, wherein the wobble carrier frequency is the center frequency corresponding to the maximum amplitude.

Abstract: The invention provides an apparatus for demodulating an Address In Pre-groove (ADIP) symbol. The ADIP symbol is carried by a wobble signal of an optical disk and comprises a series of ADIP bits permuted according to one of a plurality of permutation patterns to make up the ADIP symbol. A wobble extraction module extracts the wobble signal from the optical disk. A reference wobble generator generates a reference wobble with the same frequency and phase as a fundamental frequency and phase of a positive wobble cycle of the wobble signal. A waveform difference measurement module then measures a difference between the wobble signal and the reference wobble to obtain a series of difference measurement values respectively corresponding to the ADIP bits. A pattern matching module then compares probabilities of the permutation of the ADIP bits agreeing with each of the permutation patterns according to the difference measurement values to determine the ADIP symbol.

Abstract: The invention provides a wobble detection circuit. An exemplary embodiment of the wobble detection circuit comprises an automatic gain control module, an analog to digital converter, a digital band pass filter, and a digital band pass filter. The automatic gain control module amplifies a first input signal and a second input signal detected by a pickup head to the same magnitude to obtain a first amplified signal and a second amplified signal. The adder then subtracts the second amplified signal from the first amplified signal to obtain an analog wobble signal. The analog to digital converter then converts the analog wobble signal to a first digital wobble signal. Finally, the digital band pass filter accepts frequency components of the first digital wobble signal within a pass band and rejects frequency components of the first digital wobble signal outside the pass band to obtain a second digital wobble signal.

Abstract: A signal processing apparatus for an optical disk system which apparatus has a variable gain amplifier that amplifies with a variable gain a light-detected signal obtained from an optical disk on which to perform playback processing so as to make a level of the light-detected signal coincide with a first reference level. The apparatus comprises a comparator that compares the level of the light-detected signal amplified by the variable gain amplifier with the first reference level; a gain adjuster that generates and supplies a control signal to adjust the variable gain according to a result of the comparing to the variable gain amplifier; and a gain adjustment controller that, when the level of the light-detected signal amplified is within a level range including the first reference level, controls a level of the control signal of the gain adjuster to be held at its preceding value.

Abstract: An optical storage apparatus, a preamplifier and a method of generating a tracking error signal. The optical storage apparatus includes a pickup head, a preamplifier, and a servo control. The pickup head generates radio frequency (RF) signals. The preamplifier includes a signal adjusting apparatus, a phase detector, a charge pump, and a circuit. The signal adjusting apparatus has input terminals for receiving the RF signals. At least two of the input terminals are substantially short-circuited when the optical storage apparatus is in a calibration mode. The phase detector generates control signals based on the phase differences between the radio frequency signals. The circuit generates current control signal based on the tracking error signal when the optical storage apparatus is in the calibration mode. The current magnitude of at least one of the current sources in the charge pump is determined according to the current control signal.

Abstract: An optical storage device and a blank detection method thereof are disclosed. An RF signal is obtained from an optical disc. A various gain amplifier amplifies the RF signal based on a control signal. An analog to digital converter samples the amplified RF signal to obtain a data signal. An auto gain controller updates the control signal based on amplitude of the data signal. A blank detector detects blankness of the data signal based on a threshold. The threshold is provided by a threshold generator based on the control signal. If the amplitude of the data signal does not exceed the threshold, the blank detector sends a hold signal to suspend update of the control signal.

Abstract: There is provided an information recording/reproducing apparatus for recording or reproducing an information to or from an information recording medium having a plurality of recording layers stacked on a substrate which can always perform stable spindle rotation control irrespective of an error of a desired frequency value or the like, and which includes an optical head for recording or reproducing an information to or from the recording layers by use of an optical beam; a spindle motor for rotating the recording medium; and a drive voltage holding circuit for holding a drive voltage of the spindle motor when the optical head performs switching between the recording layers for recording/reproducing.

Abstract: A tracking error control system includes a tracking error signal generator in communication with an optical pickup head, a DC detector in communication with the tracking error signal generator and a comparator in communication with the DC detector and the tracking error signal generator. The operating optical signals received by the optical pickup head are operated with an offset signal to generate a tracking error signal. A direct current voltage of the tracking error signal is detected and compared with a reference voltage. The offset signal is adjusted according to the comparison result and fed back to the tracking error signal generator to adjust the tracking error signal.

Abstract: An apparatus and method for digitally detecting a tracking error signal using multiple phase clocks. The apparatus includes a phase extractor receiving four divided outputs in response to light reflected from an optical disk and extracting four divided phases, respectively, a phase difference detector detecting phase differences between two phases among the four divided phases, a multiple phase clock generator generating a plurality of phase clocks in response to a predetermined clock signal, a phase error detector counting phase differences in response to each of the plurality of phase clocks, summing the counted phase differences, and detecting a phase error, and a tracking error output unit detecting the tracking error signal in response to the phase error and outputting the detected tracking error signal.

Abstract: A method for calibrating a recording track offset of an optical storage device accessing an optical storage medium of a land and groove recording/reproduction type includes: setting at least one control parameter of a track offset control loop of the optical storage device to drive the track offset control loop to enter an first state; and recording data onto the optical storage medium with the track offset control loop being enabled to derive the latest value of the recording track offset, where the track offset control loop is utilized for controlling the recording track offset. The method further includes setting the control parameter to drive the track offset control loop to enter a second state, where a loop response of the track offset control loop in the first state is different from that in the second state.

Abstract: A servo control signal generation device for discriminating a kind of an optical disk, changing over between top and bottom envelope signals of an RF signal, and generating a defect signal and a mirror signal includes an RF generator for generating the RF signal from reflected light of an optical disk, a disk discriminator for discriminating a kind of the optical disk from the RF signal, and a top envelope generator and a bottom envelope generator respectively for generating the top and bottom envelope signals of the RF signal. If the disk has reflectance after recording which is lower than that before recording, the defect and mirror signals are generated respectively from the top and bottom envelope signals. If the disk has reflectance after recording which is higher than that before recording, the defect and mirror signals are generated respectively from the bottom and top envelope signals.

Abstract: A disc drive apparatus (1) for optical discs (2) comprises: a frame (3); a sledge (10) displaceably mounted with respect to said frame (3); a lens actuator (43, 21) displaceably mounted with respect to said sledge (10); and a control unit (90) for generating a control signal (SCL) for the lens actuator (43, 21). The control unit (90) is designed, during a jump operation, to generate said control signal (SCL) for the lens actuator (43, 21) on the basis of an actuator deviation signal (SAS) representing a difference between actuator position (XA) and sledge position (XS).

Abstract: In a repetitive control device used for processing a servo signal, a memory (7) is used as a delay element for a filter (6), and a filtering process by the filter (6) is carried out using a clock signal that is an integral multiple of an operation frequency of a driving signal. Therefore, the gain can be increased without generating phase rotation with respect to a compensated signal, and high followability can be achieved to fluctuations in the track position which are caused by the shape of a disc such as decentering or surface wobbling, during recording and playback in an optical disc device.

Abstract: A focusing controller and a method thereof for an optical disk drive. The focusing controller includes a filter which filters out a high-frequency component of the track error signal to output an adjusted signal, a coupler which couples the focus error signal with the adjustment signal to generate a coupled signal. The focusing controller further includes a focus compensator which receives the coupled signal and output the focus control signal to control position of the pick up head of the optical disk drive out of focus such that the coupling of the track error signal with the focus error signal is improved and also the stability of the servo system. While seeking ended, the offset signal is removed to resume the position of the optical pick-up head to the normally focus position.

Abstract: A high-density read-only optical disc, and an optical disc apparatus and method using the same. The apparatus and method record data on a lead-in area of a high-density read-only optical disc such as a BD-ROM (Blu-ray disc ROM (Read Only Memory)) in the form of pre-pit strings associated with an HFM (High-Frequency Modulated) groove applied to a BD-RW (Blu-ray Disc Rewritable). Moreover, the apparatus and method continuously apply the same tracking servo operation to an entire area of the same high-density read-only optical disc or rewritable optical disc. Therefore, the apparatus and method can simplify an algorithm for controlling a plurality of tracking servo operations, and avoid an increased size of the optical disc apparatus.

Abstract: An optical disc apparatus includes: a converging section for converging a light beam and irradiating a rotating information medium with the converged light beam; a moving section for moving the converging section, thereby moving a converging point of the converged light beam in a direction perpendicular to an information surface of the information medium; a converging state detection section for generating a focus servo signal which represents a converging state of the light beam on the information medium based on reflected light or transmitted light of the light beam from the information medium; a focus servo control section for controlling the moving section based on the focus servo signal, so that the light beam reaches a predetermined converging state on the information medium; and a focus pull-in section for turning ON the control by the focus servo control section, wherein the focus pull-in section turns ON the control by the focus servo control section in a case where the focus pull-in section determin