Abstract: The present invention provides a method for adaptively driving a tracking element with mechanical deviation and a driving device using the same. The method comprises the following steps: recording standard moving time and a standard motor current value, supplying driving voltage to a motor for driving a tracking element, detecting a current value of the motor and detecting moving time of the tracking element, and adjusting a driving gain of the motor based on the relation between the current value of the motor and the standard motor current value, and based on the relation between the moving time of the tracking element and the standard moving time of the standard one.

Abstract: The present invention provides an apparatus of an optical disc drive for adjusting a focus error signal. The apparatus includes a focus offset determining unit and an adjusting module. The focus offset determining unit is utilized for determining a target focus offset corresponding to a target condition, and the adjusting module is coupled to the focus offset determining unit and utilized for receiving the focus error signal and adjusting the focus error signal with the target focus offset to generate an adjusted focus error signal.

Abstract: An optical pickup apparatus comprising: a laser-light source that selectively emits first and second laser lights parallel with each other; a diffraction grating that includes a plurality of periodic structures joined to be different in phase from each other in a direction optically corresponding to an optical-disc-tracking direction, and generates 0th-order and ±1st-order-diffracted lights by diffracting the first or second laser light; an objective lens that focuses the 0th-order and ±1st-order-diffracted lights generated from the diffraction grating on the same track of the disc; and a photodetector to which reflected light of the 0th-order and ±1st-order-diffracted lights focused on an optical disc is applied through the objective lens, and which generates a differential-push-pull signal, a direction of a straight line connecting light-emitting points of the first and second laser lights in the laser-light source being inclined relative to the direction optically corresponding to the optical-disc-tracking

Abstract: An optical disk device has: a detector (11) that converts a reflected light from an optical disk (5) and a reflected light of an incident light from a light source (1) side of a solid immersion lens (4), into electric signals and outputs the signals; a subtracter (15) that computes the output signal of the detector (11) according to a predetermined rule and outputs the result as a tilt detection signal; a CPU (21), an amplifier/phase compensation circuit (16), a switch (17) and an actuator (13) that perform tilt control for controlling tilt of the solid immersion lens (4) with respect to the optical disk (5) using the tilt detection signal; and the CPU (21), a nut (24), a feed screw (25), a decelerator (26) and a stepping motor (27) that perform gap adjustment for changing the gap of the solid immersion lens (4) and optical disk (5), and in the process of adjustment of gap between the solid immersion lens (4) and optical disk (5), the CPU (21) enables tilt control by closing the switch (17) according to the t

Abstract: An optical disk device executes a seek operation to move an irradiation position of light beam on an optical disk to a track of a target address. During execution of a seek operation through a one-track jump operation in which the irradiation position of the light beam is moved along the radial direction of the optical disk by one track, it is determined whether or not off-track of the irradiation position of the light beam has occurred. When it is determined that the off-track has occurred, a seek operation through a multiple track jump operation is executed in which the irradiation position of the light beam is moved along the radial direction of the optical disk by an amount corresponding to a plurality of tracks.

Abstract: A method of reducing power dissipation in a variable-gain photo-detector circuit is described. The variable-gain photo-detector circuit has an output to output a main spot signal and at least one side spot signal. The main spot (M) and the side spot (Si or S2) are formed by separating a light beam into a main beam and at least one side beam and focusing the main beam on the main spot (M) and the side beam on at least one side spot (Si or S2) on an optical record carrier The method processes the main spot signal with a first averaging circuit having a first cut-off frequency. The side spot signal is processed with a second averaging circuit having a second cut-off frequency. The second cut-off frequency is lower than the first cut-off frequency. The above technique reduces power dissipation in the variable-gain photo-detector circuit and is useful for all optical devices.

Abstract: An optical disc device and tracking control method capable of stable tracking control even for inferior optical discs with tracks decentered by a large amount. The optical disc device and tracking control method includes: obtaining a rotation angle at which the degree of displacement of the track due to the eccentricity of the optical disc becomes maximum on the inner circumference side and the outer circumference side, and detecting the eccentricity amount of the optical disc; and performing track pull-in at the rotation angle, at which the degree of displacement of the track due to the eccentricity of the optical disc becomes maximum, detecting a displacement direction of the optical disc at the time of the pull-in, and moving the slider in the detected displacement direction for a distance equal to or almost equal to the eccentricity amount of the optical disc.

Abstract: A tilt sensor includes a photodetector having a photosensitive plane and detecting a light beam in multiple areas and outputting detection signals representing its intensities and a tilt detector for generating a tilt error signal, including information about the tilt of a disk, based on the detection signals. The light beam forms a beam spot on the photosensitive plane. The beam spot includes a +first-order light area in which zero-order and +first-order light rays, diffracted by a track on the disk, are superposed, ?first-order light area in which zero-order and ?first-order light rays are superposed, and a zero-order light area which is sandwiched between the +first-order and ?first-order light areas, includes neither the +first-order nor ?first-order light ray, but includes a zero-order light ray. The photodetector generates the detection signals except for light entering an opaque area provided for at least part of the zero-order light area.

Abstract: A method and apparatus of compensating for misalignment in an optical disk device includes detecting a plurality of focus error signals, comparing the focus error signals, and shifting a position of an optical lens based on the comparison. Alternatively, a one or more of the focus error signals may be compared to a reference signal and a corresponding shift may be performed. When the lens is shifted, an optical spot corresponding to an optical beam reflected from a disk surface is corrected to a position which reduces or eliminates misalignment errors attributable to one or more elements of the pickup.

Abstract: A disc discriminating method for use in an optical disc drive includes the following steps. Firstly, an optical pickup head of the optical disc drive is controlled to move in a first direction when the optical pickup head is in a track-unlocked state. Then, a tracking error signal and a radio frequency signal are generated. According to the tracking error signal, a tracking error zero crossing signal is obtained. According to the radio frequency signal, a radio frequency zero crossing signal is obtained. According to a phase relation between the tracking error zero crossing signal and the radio frequency zero crossing signal, the disc is discriminated as an on-groove recording disc or an in-groove recording disc.

Abstract: A method for inspecting an optical information storage medium includes irradiating the medium with a laser beam and rotating the medium by a constant linear velocity control technique by reference to the radial location at which the laser beam forms a spot on the medium; changing the rotational velocities according to the radial location on the medium between at least two linear velocities; generating a focus error signal and/or a tracking error signal based on the light reflected from the medium; performing a focus control and/or a tracking control on the laser beam based on the focus and/or tracking error signal(s); and passing the branched outputs of control loops for the focus and/or tracking error signal(s) through predetermined types of frequency band-elimination filters to obtain residual errors of the focus and/or tracking error signal(s) and comparing the residual errors to predetermined reference values.

Abstract: The present invention relates to a method for operating an optical drive system (12) capable of reproducing/recording information from/to an optical carrier (1), wherein the optical drive system includes a focus controller (PID) for controlling a focus actuator (4), and a focus memory loop (ML) for applying a stored correction signal to the focus actuator (4). The method aims at avoiding impacts between the focussing means (3) and the optical carrier (1), by gradually stopping the focus control loop in response to an event, such as a user initiated ejection of the optical carrier. The gradual stop of the focus control loop is achieved by gradually reducing a memory loop parameter of the focus memory loop (ML), and by gradually reducing a controller parameter of an integrating part (I) of the focus controller (PID). It is an advantage of the invention that the phase of the stored correction signal is synchronized with the angular position of optical carrier (1) during the gradual stopping.

Abstract: An optical disk device includes a DPDTE signal generating section that detects misalignment between a light spot and a mark or a pit, an FE signal generating section, an optical crosstalk correcting section which corrects a signal output by the FE signal generating section using the DPDTE signal generating section, and a focus control section which controls an actuator so that a light beam converges on an information layer. The DPDTE signal generating section detects the misalignment on the basis of phase information obtained from signals received from predetermined light receiving areas. The optical crosstalk correcting section performs a correcting operation of removing a signal component from predetermined receiving areas of a detector which component is used for a DPDTE signal, the signal component being contained in the signals from the predetermined light receiving areas of the detector which signals are used by the FE signal generating section.

Abstract: A method for inspecting an optical information storage medium includes irradiating the medium with a laser beam and rotating the medium by a constant linear velocity control technique by reference to the radial location at which the laser beam forms a spot on the medium; changing the rotational velocities according to the radial location on the medium between at least two linear velocities; generating a focus error signal and/or a tracking error signal based on the light reflected from the medium; performing a focus control and/or a tracking control on the laser beam based on the focus and/or tracking error signal(s); and passing the branched outputs of control loops for the focus and/or tracking error signal(s) through predetermined types of frequency band-elimination filters to obtain residual errors of the focus and/or tracking error signal(s) and comparing the residual errors to predetermined reference values.

Abstract: A method for inspecting an optical information storage medium includes irradiating the medium with a laser beam and rotating the medium by a constant linear velocity control technique by reference to the radial location at which the laser beam forms a spot on the medium; changing the rotational velocities according to the radial location on the medium between at least two linear velocities; generating a focus error signal and/or a tracking error signal based on the light reflected from the medium; performing a focus control and/or a tracking control on the laser beam based on the focus and/or tracking error signal(s); and passing the branched outputs of control loops for the focus and/or tracking error signal(s) through predetermined types of frequency band-elimination filters to obtain residual errors of the focus and/or tracking error signal(s) and comparing the residual errors to predetermined reference values.

Abstract: A focusing servo device, an optical disc recording/reproducing device and a focus-searching method are provided for making a focus of an energy beam emitted by a pick-up unit to fall in an accessible range of a data layer of a disc. The method comprises the following steps: recording the deviation of the focal point during each predetermined period when the focal point of the energy beam is fallen in the accessible range such that the optical disc recording/reproducing device is operated in a feedback control mode; determining a focus-searching range based on the recorded deviation of the focal point; and moving the focal point in the focus-searching range to make the focal point to fall in the accessible range when the focal point of the energy beam is fallen out of the accessible range such that the optical disc recording/reproducing device is operated in a focus-searching mode.

Abstract: In an optical disc apparatus, whether an unrecorded recording layer without information recorded thereon is included in the multiple recording layers of the optical disc mounted inside the apparatus is judged. then when the unrecorded recording layer is judged to be present, a signal for focus offset adjustment is recorded in a non-user data recording area of the unrecorded recording layer, and reproduction of the recorded focus offset adjusting signal is followed by its quality evaluation, which is further followed by calculation and setup of an appropriate focus offset value based on evaluation results.

Abstract: A dual-layer structure phase-change type optical recording medium includes a substrate (1), a reflective layer (2), a first protective layer (3), a first recording layer (4), a second protective layer (5), a resin intermediate layer (6), a third protective layer (7), a heat release layer (8) made of Cu or a Cu alloy, a fourth protective layer (9), a second recording layer (10), a fifth protective layer (11) and a cover substrate (12). A product of a reflectance of a high-reflection part and a modulation after recording is a value equal to or higher than a lower limit value for reproduction.

Abstract: When an optical disc apparatus reproduces information from an optical disc, it converges a reading light beam emitted from an LED to substantially collimated light and projects it to the optical disc to cause it to be reflected by reflection surface thereof so as to make it become a reading reflected light beam. Then, the apparatus converges the reading reflected light beam by a mark layer selection lens, detects the reading reflected light beam passing through the target position by a detection region located at the confocal point of the target position and generates a detection signal. Subsequently, the apparatus recognizes the presence or absence of a recording mark based on the detection signal to reproduce the information. Thus, the apparatus can detect the state of the reading reflected light beam observed when it passes the target position and can recognize the presence or absence of a recording mark.

Abstract: An optical disc device includes a control part for causing processing of determining a type of an optical disc to be executed. The processing caused by the control part to be executed for determining the optical disc includes: signal acquisition processing of acquiring a pull-in signal (sum signal of reflected signal) and an RF signal (reproduced signal) by moving an objective lens in either of a direction approaching the optical disc and a direction separating from the optical disc; and determination processing of deciding whether or not to correct the pull-in signal acquired in the signal acquisition processing and determining the type of the optical disc by using either of amplitude of the acquired pull-in signal and a correction value with which the amplitude of the acquired pull-in signal is corrected by using a predetermined value obtained from the acquired RF signal.

Abstract: An optical head device includes a light source (30) configured to emit a light beam, a light collecting optical system configured to converge the light beam onto an information recording medium (10), a hologram element (20) configured to diffract the light beam reflected from the information recording medium (10), and a photodetector (40) having a plurality of detection regions configured to receive the light beam diffracted by the hologram element (20). The hologram element (20) has two diffraction regions (261 and 262) separated from each other by a straight line (260) extending in a radial direction of the information recording medium (10). At least one of the two diffraction regions has a pattern which introduces coma aberration in the radial direction. The light diffracted by the diffraction region having the coma aberration has coma aberration in the radial direction.

Abstract: The present invention provides an optical disk apparatus capable of stably performing a layer jump on an optical disk having plural recording layers and non-uniform interlayer distances. In an optical disk with at least three recording layers and non-uniform interlayer distances between respective recording layers, if a layer jump is carried out from a first recording layer to a second recording layer, a distance from the first recording layer to the second recording layer is obtained and driving voltages set according to the distance are applied to an actuator for the layer jump to carry out the layer jump. At this time, interlayer distances for combinations of the respective recording layers and applied driving voltages thereto are stored in a memory in advance and when necessary, corresponding driving voltages are read out from the memory and are set for the layer jump.

Abstract: Defocus detection device and method capable of detecting a defocus accurately during recording of information to an optical disk having a plurality of recording layers and an optical disk unit using the device and method are provided. A temporal restriction is imposed on defocus detection and besides, in comparison with a level for detection of a first change of a focus error signal developing during a defocus, a level for detection of a successively occurring second change of a polarity inverse to that of the first change is made to be smaller. When the first level is exceeded and thereafter the second level is exceeded within a restricted time, a defocus is detected.

Abstract: A model is derived for write parameters of a laser in an optical drive. A parameter range for the write parameters is set based on a recordable medium. A number of test runs are recorded on the recordable medium while varying the write parameters. Write performance characteristics are measured over the test runs, and a model of write performance as a function of the write parameters is derived. Values for write parameters are selected for use in writing actual data based on the derived model. A first section of user data is written to the data-carrying region of the recordable medium using the selected values. The write performance characteristics of the first section of user data are measured, and the model is updated by including the measurements from the data-carrying region. New values for the write parameters of the laser are selected based on the updated model.

Abstract: In the present invention, at the time of pulling a focus on an information recording surface of a disc, a focus servo is first pulled in a disc surface of the disc, and with the servo in a settled state, a driving signal necessary for following surface wobble is stored, and a focus is pulled in the information recording surface of the disc based upon a signal superimposed with the driving signal and a focus search driving signal.

Abstract: In an optical pickup device and a method of a focus jump, in order to make optimum correction of spherical aberration responsive to the position of a recording layer at one end nearer a target recording layer than a current in-focus recording layer, the recording layer at the one end being one of recording layers at opposite ends of a plurality of recording layers, spherical aberration correcting means is controlled, and then a focus actuator is controlled, thereby causing a focus to jump to the recording layer at the one end. Next, in order to make optimum correction of spherical aberration responsive to the position of a different recording layer shifted by at least one recording layer from the recording layer at the one end toward the target recording layer, the spherical aberration correcting means is controlled, then the focus actuator is controlled, the focus is caused to jump to the different recording layer, and such a focus jump is repeated until the focus reaches the target recording layer.

Abstract: An optical pickup apparatus reads an information signal recorded on a recording surface of an optical disk along a track by projecting a light beam. Said optical pickup apparatus has: an objective lens for converging said light beam onto said recording surface; an objective lens moving device for moving said objective lens in a radial direction of said optical disk; and a divisional photosensing device for receiving return light reflected by said optical disk, in a plurality of divided regions.

Abstract: A gap pull-in method and an optical disc apparatus. Whether light condensed on a disc as an actuator ascends is near-field light is determined using a gap error signal. The range of an actuator driving voltage value during a section where the decrease rate of the gap error signal is constant is obtained when it is determined that the light condensed on the disc is near-field light. Gap pull-in is performed on the disc during a section where the actuator driving voltage value is within the obtained range.

Abstract: A method for determining a focus height of an optical disc drive is provided. A disc is placed into the optical disc drive. An objective lens is moved to lock a focus on a data layer of the disc. The objective lens is radially moved from inner tracks to outer tracks, and at the same time the focus voltages at the radial position are recorded. A focus voltage curve is curve-fitted based on the recorded focus voltages. A corresponding refocus voltage is obtained from the focus voltage curve according to the radial position where a focus drop occurs. The objective lens is moved to the focus height by the refocus voltage for refocusing.

Abstract: The present invention is directed to an optical disk drive in which laser beams are emitted to an optical disk in a state of not rotated, and simultaneously an objective lens which collects the laser beams is moved to a direction approaching the optical disk at a constant speed, a time length required for moving a focused position of the laser beams from a surface of the optical disk to a recording layer is measured by observing a reflected light from the optical disk, and a type of the optical disk is determined based on the time Tdet thus measured, includes a control means which executes, a calculating process which calculates an additional travel time Tadd, based on the Tdet and an in-periphery maximum surface wobbling amount Vd of the optical disk, a moving process which further moves the objective lens for the additional travel time Tadd at the constant speed after the laser beams are focused on the recording layer, a rotating process which rotates the optical disk, a move-away process which moves the ob

Abstract: An optical disc device includes: a light source; a condensing system including a solid immersion lens for emitting light from the light source onto an optical disc; a gap control circuit for setting a distance between the solid immersion lens and the optical disc to a constant value; a CPU for adjusting a condensing position of emission light from the solid immersion lens with respect to an information recording/reproducing surface of the optical disc by moving a concave lens in a direction of an optical axis; and a focus control circuit for setting the condensing position on the information recording/reproducing surface, while following plane displacement of the information recording/reproducing surface, using a focus error signal. The CPU is operable to correct coma aberration in focus position adjustment by moving the concave lens in a direction perpendicularly intersecting with the optical axis.

Abstract: An apparatus and method to write/reproduce data to/from an optical disc, which are capable of preventing an error from occurring at the time of examination of a writing strategy and searching for an optimum writing condition for a short period of time, by examining the writing strategy after adjusting a focus in a test region, in order to set a writing condition at the time of writing data. The apparatus to write/reproduce data to/from an optical disc includes a matrix jitter measuring unit which measures length errors and jitters of edges of a mark and a space of a written data pattern from an RF signal generated at the time of reproduction of the optical disc; and a CPU which extracts at least one of the RF signal, a jitter and an error rate, controls a focus bias, and performs an optimum power calibration (OPC) for searching for optimum power of laser.

Abstract: A detector is scanned across an optical storage medium having groove tracks and land tracks, each track having a wobble structure, to detect light reflected from the optical storage medium. A wobble signal and a tracking error signal are generated based on an output of the detector, and the wobble signal is sampled according to the tracking error signal. A determination about whether the detector is at the groove track or the land track is made based on the tracking error signal and a comparison of sampled values of the wobble signal.

Abstract: In a method for adjusting a focus position for an optical disc, onto/from which in formation is recorded or reproduced, while adjusting the focus position of an optical reproducing means, upon a recording surface of an optical information recording medium having an area where information of the optical information recording medium is recorded in advance, comprising the following steps of: memorizing plural numbers of information relating to focus positions determined appropriately, which can be obtained from the area where the information of the optical information recording medium is recorded in advance; and adjusting the focus position for the optical disc loaded into an apparatus, from at lease one (1) signal relating to the focus position, which can be obtained from the optical disc, with utilizing a relationship between the plural numbers of information relating to the focus positions determined appropriately, memorized in advance, when reproduction of the information is impossible when the optical disc

Abstract: An optical disc apparatus comprises an overcurrent detector and when the overcurrent detector detects an overcurrent during a recording operation or a reproduction operation and during an operation for controlling a focus of an objective lens, a rotation speed of an optical disc is reduced and an actuator is controlled to cause the objective lens to be in a retracted state under the condition that a disc motor exerts brake force. The objective lens is in the retracted state until the rotation speed of the optical disc becomes equal to or smaller than a predetermined value and when the rotation speed of the optical disc is equal to or smaller than the predetermined value, the objective lens is released from the retracted state.

Abstract: Various embodiments for addressing time-varying periodic disturbances in a servo control system are provided. Each of a plurality of coefficients is updated based on an estimation of at least one disturbance frequency. The updated plurality of coefficients is provided to at least one peak filter modifying an input signal of the servo control system. The peak filter is operable in view of the updated plurality of coefficients to cancel at least one of the time-varying periodic disturbances.

Abstract: An optical disk device includes an optical pickup, a focus drive section, a detection section, a time measurement section and a disk identification section. The detection section detects reflected light reflected from an optical disk while the focus drive section moves a focus position of the optical pickup. The time measurement section measures a focus search time between when the reflected light reflected from a disk surface of the optical disk is detected and when the reflected light reflected from an information recording layer of the optical disk is detected. The time measurement section measures a false reflection search time between when the reflected light reflected from the disk surface is detected and when false reflection light is detected. The disk identification section calculates a ratio of the focus search time to the false reflection search time, and identifies a type of the optical disk based on the ratio.

Abstract: An apparatus for recording and reproducing an information signal on and from an optical disc includes a memory. The information signal is written into the memory. The information signal is read out from the memory. An optical head generates a laser beam in response to the readout information signal, and applies the laser beam to the optical disc to record the readout information signal on the optical disc. A test signal is recorded on a position of the optical disc near a recording position thereof via the optical head during the writing of the information signal into the memory. The test signal is reproduced from the optical disc. The reproduced test signal is evaluated to generate an evaluation result. An intensity of the laser beam is optimized in response to the evaluation result.

Abstract: A focusing control method of an optical information storage media recording and/or reproduction apparatus controlling a focusing operation by moving an objective lens upwards or downwards in a direction towards or away from an optical information storage medium having a plurality of data layers includes receiving a focusing lead-in command signal to focus an optical beam on a target data layer, compensating for spherical aberration with respect to the target data layer, detecting a focus error signal based on an intensity of the optical beam reflected from the optical information storage medium and condensed by an optical detector, identifying the target data layer using an amplitude or a frequency of the focus error signal, and focusing the optical beam on the target data layer by moving the objective lens in an opposite direction from a direction in which the objective lens is initially moved.

Abstract: An optical disc drive includes: an optical branching element for splitting light from a light source into main and sub-beams; a condenser element for condensing the main and sub-beams; a photodetector section including photodetectors to receive reflected portions of the main and sub-beams, each photodetector having photosensitive areas, each of which outputs a signal representing the intensity of light received there; and a computing section for generating a first focus signal, representing where the focal point of the main beam is located with respect to the storage layer, based on the reflected light of the main beam, and a second focus signal based on the reflected light of the main and sub-beams.

Abstract: An optical pickup apparatus includes a first objective lens having a low numerical aperture (NA) suitable for a low-density recording medium, a second objective lens having a high NA suitable for a high-density recording medium, a first light source to generate a short-wavelength optical signal to use the first and second objective lenses, a first photo-detector to receive an optical signal, which is generated from the first light source, is focused on a recording medium by the first and second objective lenses, and is then reflected from the recording medium, and a beam splitter to perform a division of the optical signal generated from the first light source, to direct some parts of the divided optical signal to the first objective lens, and to direct the other parts of the divided optical signal to the second objective lens.

Abstract: A tracking control is performed based on a first tracking error signal obtained from a first light beam reflected on an optical recording medium and a second tracking error signal obtained from a second light beam reflected on the optical recording medium. The first tracking error signal is corrected when recording information to or reproducing information from a first information recording layer that includes a first area facing an area on a second information recording layer with no information recorded and a second area facing an area on the second information recording layer with information recorded.

Abstract: The method prevents an optical disk from being scraped by an optical apparatus of a pickup head of an optical disc drive is disclosed, it mainly includes: moving the optical apparatus of the pickup head to a detection position in which the laser-light emitted from the pickup head focuses on the optical disk; detecting the first-detection position and setting a movement boundary according to the first-detection position, wherein the movement boundary has a upper boundary and a bottom boundary; preventing the optical apparatus from moving out of the movement boundary. The present method can be implemented without installing any additional apparatus in the original video disc player, and can prevent the optical disk and the inner apparatus of the optical disc drive from being scraped or damaged by the pickup head during a read/write process to increase the service life of the optical disk and the optical disc drive.

Abstract: This document relates to a method of compensating for a sensitivity variation of a tracking actuator with focusing offset when recording labels on a disc for label recording. A focusing point suitable for the position of an object lens in the circumference direction and/or the radius direction is detected, a tracking sensitivity corresponding to the detected focusing point is obtained based on information about a tracking sensitivity variation according to a focusing point variation, and labels are recorded on a label plane using the detected focusing point and tracking sensitivity. The information may be measured using at least two different types of discs one of which has a distance, between the surface of the disc and a pattern area required for a feed forward servo operation, different from the distance of the other.

Abstract: A device for detecting defect signals on an optical disc includes a finite state machine (FSM) to control a servo system of an optical disk drive. When the FSM is in a DETECT state and defect signals are greater than thresholds, a detection counter is set to a first predetermined value and the FSM enters an ARM state. In the ARM state, when the detection counter counts zero, the FSM enters a KICK state and the detection counter is set to a second predetermined value. In the KICK state, a flag signal XDFCT is asserted. When the detection counter in the KICK state counts to zero, the FSM enters a WAIT state and the detection counter is set to a third predetermined value. When the flag signal XDFCT is asserted, corresponding servo control signals for the servo system are clamped to a programmable constant voltage.

Abstract: A defect detection unit (5), a disc position detection unit (9), and a disc rotation speed detection unit (1) are in a disc control device which includes a repetition control device to control storing to and reading from a memory unit (3) functioning as a learning memory and for varying the number of memory divisions of the memory unit (3) on the basis of detection by the detection units. Components having periodicity apparently due to partial surface runout or partial eccentricity are stored in memory unit (3) by increasing the resolution and microscopic noise components, and noise components having no periodicity are not stored in memory unit (3). This system carries out stable focus tracking control even when disturbances such as device vibration or scratches on a disc are mixed.

Abstract: The present invention relates to a method and an apparatus of adjusting a focusing servo in an optical disc device. According to an embodiment of the present invention, a focusing servo is coarsely adjusted using a tracking error signal for a blank disc, data is recorded in a predetermined area of the disc, and then the focusing servo is finely adjusted using the characteristics of a reproduced signal for the recorded data. In this case, the focusing servo is adjusted to adjust a focusing position of an objective lens, and the predetermined area is a region provided on the disc to detect optimum recording power. The characteristics of the reproduced signal include magnitude and/or jitter value of the reproduced RF signal. Therefore, the present invention can optimally adjust a focusing servo even for a blank disc, and can improve data recording quality.

Abstract: The invention relates to an optical disk drive. The optical disk drive has an objective lens to be driven by a focus actuator with a focus offset for focusing an incident beam onto an optical disk into a spot with a spherical aberration, and a processor to derive a first and a second characteristic from a sensor output signal and obtain a spherical aberration correction value (SA) from a pre-determined function, the pre-determined function defining a spherical aberration correction value in dependence on a focus offset difference value (?FO). The focus offset difference value (?FO) is determined from a difference between a second optimal focus offset at which the second characteristic is optimal and a first optimal focus offset at which the first characteristic is optimal. The spherical aberration correction value (SA) can be used to achieve a correction to the spherical aberration of the spot.

Abstract: A holographic storage and reproduction system and method with a servo are provided, wherein a servo mechanism is provided, such that the holographic interferogram is continuously stored in the holographic recording medium. When a reproduced signal is to be obtained, it can be retrieved quickly and accurately through the servo mechanism. Also, the intensity distribution of the reference light reflected by the holographic recording medium can be monitored and controlled, such that the relative distance and oblique angle between the storage and reproduction system and the holographic recording medium are analyzed and adjusted.

Abstract: An optical storage system includes a pickup head for picking up data from a storage medium. Firstly, the maxima of a tracking error signal and runout are obtained in a calibration procedure in a close loop formed by an optical pickup head, a pre-amplifier, a compensator, a band-pass filter and a maximum detector. A calibration factor is then defined and derived by using the obtained maxima and nominal factors of a power amplifier and the optical pickup head of the optical storage system. The path formed by the series-connected band-pass filter and maximum detector is then disabled, while the calculated calibration factor is then stored in the compensator. The optical storage system may operate in a close loop formed by the optical pick head, pre-amplifier, compensator, a power amplifier under a normal operation procedure so that the optical storage system may record or read data onto/from an optical disc under the compensation provided by the calibration factor.