Abstract: A data storage device is disclosed comprising a head actuated over a disk. The head is used to read servo information from the disk and generate a position error signal (PES) representing a position of the head over the disk. A control signal is generated based on the PES and a triangle-shape dither signal, and the head is positioned over the disk using the control signal.

Abstract: A peak location calculation device includes a peak value detection block that detects a plurality of candidates for a peak value of intensity of laser light received by an imaging unit consisting of an imaging element formed of a plurality of pixels, and a peak location calculation block that calculates an approximation function that approximates an intensity distribution of the laser light using the plurality of candidates for peak values detected by the peak value detection block. The peak location calculation block calculates the approximation function that minimizes an error between intensity values of the plurality of candidates for the peak value and values of the approximation function.

Abstract: A set of first signal light and reference light with a phase difference of almost 0 degree, a set of second signal light and reference light with a phase difference of almost 180 degrees, a set of third signal light and reference light with a phase difference of almost 90 degrees, and a set of fourth signal light and reference light with a phase difference of almost 270 degrees are generated. A first differential signal as a difference between a first light-receiving signal obtained by a first light-receiving element and a second light-receiving signal obtained by a second light-receiving element is calculated, and a second differential signal as a difference between a third light-receiving signal obtained by a third light-receiving element and a fourth light-receiving signal obtained by a fourth light-receiving element is calculated. The first differential signal and the second differential signal are supplied to respective FIR filters.

Abstract: Exemplary embodiments of present invention relate to an error detecting apparatus for a gate driver improving a reliability of a display apparatus, a display apparatus having the error detecting apparatus, and a method of detecting an error of the gate driver using the error detecting apparatus. An exemplary embodiment discloses an error detecting apparatus including an error detecting part configured to receive a gate signal of a gate driver and determine whether a status of the gate driver is in a normal status or an error status based on the gate signal, a memory configured to store the status of the gate driver, and a signal outputting part configured to selectively output a clock signal and an error signal based on the status of the gate driver stored in the memory.

Abstract: There is provided a light source including a mode-lock laser unit that includes a semiconductor laser and an external resonator unit and emits a laser beam having a predetermined frequency, the semiconductor laser including a saturable absorber unit that applies a reverse bias voltage and a gain unit that applies a gain current, a semiconductor optical amplifier that performs amplification modulation on the laser beam emitted from the mode-lock laser unit, a laser clock generating unit that generates a laser clock synchronized with the laser beam based on a signal detected from the saturable absorber unit when the laser beam oscillates in the mode-lock laser unit, and a modulating unit that generates a driving current synchronized with the laser clock and applies the driving current to the semiconductor optical amplifier.

Abstract: A laser apparatus and bio-imaging apparatus are provided, which include: a mode-lock laser unit including a saturable absorber section that applies a bias voltage, a gain section that feeds a gain current, a semiconductor laser that emits laser light, and an external resonator; an optical modulation unit performing amplification modulation on the laser light emitted from the mode-lock laser unit; a reference signal generation unit generating a master clock signal and supplying a signal synchronized with the master clock signal to the gain section of the semiconductor laser; and a driving circuit generating a driving pulse used to drive the optical modulation unit based on the reference signal.

Abstract: There is provided an recording apparatus including a light irradiation unit, a reference-plane tracking control unit, a recording unit that executes recording on the recording medium by independently modulating first and second recording beams when the recording beams radiated by the first and second objective lenses are designated as the first and second recording beams, respectively, a recording-layer tracking control unit that performs tracking control of the first objective lens based on reflected light of a first servo beam and tracking control of the second objective lens based on reflected light of a second servo beam when the servo beam radiated by the first objective lens is designated as the first servo beam and the servo beam radiated by the second objective lens is designated as the second servo beam, and a control unit that controls the reference-plane tracking control unit, the recording-layer tracking control unit, and the recording unit.

Abstract: A data phase locked loop circuit includes a phase locked loop circuit, a judging circuit, a detecting circuit and a control circuit. The phase locked loop circuit outputs a reference signal according to a data signal, which is generated by an optical drive reading an optical disk. When the judging circuit judges that a jitter signal is smaller than a threshold value, the control circuit stores a frequency of the reference signal. When the detecting circuit detects a defect zone of the optical disk read by the optical drive, the phase locked loop circuit fixes the frequency of the reference signal to a latest stored one.

Abstract: An optical drive apparatus that reproduces an optical disk having a land and a groove, the optical drive apparatus including a first tracking-error-signal generating unit that generates a first tracking error signal by using a DPD method, a second tracking-error-signal generating unit that generates a second tracking error signal by using a DPP method, a tracking servo unit that controls the optical system, and a determining unit that determines that an irradiation point of an optical beam is in a non-recorded area. The tracking servo unit switches over to a control based on the second tracking error signal in response to a result of determination by the determining unit during performing a control based on the first tracking error signal.

Abstract: A method for controlling an OPU and an optical data access apparatus are provided. A signal generator is configured to generate a servo signal in response to data access. A comparator is configured to compare a threshold level and the servo signal, and generate a control level if a level of the servo signal against the threshold level when the OPU is controlled. An adjustment unit is configured to adjust a control signal according to the control level. The OPU is controlled according to the adjusted control signal.

Abstract: There is provided a position control apparatus including a light radiating/receiving unit that performs radiation of laser light for recording and laser light for adjacent track servo onto an optical disc recording medium through a common objective lens, and receives return light of the laser light for the adjacent track servo and the laser light for the reference surface, a tracking mechanism unit that displaces the objective lens, a reference surface tracking error signal generating unit that generates a reference surface tracking error signal, a reference surface tracking servo control unit that controls the tracking mechanism unit, a recording layer tracking error signal generating unit that generates a recording layer tracking error signal, an integrating unit that integrates the recording layer tracking error signal, an offset providing unit that provides an integration output by the integrating unit, and a feedforword control unit that generates a control signal.

Abstract: New and useful methods and systems for reading optical discs, such as multi-layer Blu-ray discs are disclosed. For example, in an embodiment a device for reading two-layered optical discs includes a laser diode capable of emitting light, a set of optics including a fixed collimator, the set of optics providing a numerical aperture (NA) of substantially less than 0.85, and a detector for detecting laser light focused on a two-layer optical disc to produce a stream of detected bits.

Abstract: An optical recording medium in which recording is performed by a recording device that is configured such that tracking servo control of recording light is performed by irradiating the recording light and ATS light for an adjacent track servo and by an adjacent track servo based on reflected light of the ATS light, wherein while a recording layer in which a mark is formed according to an irradiation of the recording light is included, a mark row is formed in advance by a pitch that is twice a distance between an irradiation spot of the recording light and an irradiation spot of the ATS light or greater in the recording layer.

Abstract: A servo processor for an optical disk drive is provided that includes: an analog-to-digital converter for converting versions of photodetector output signals into digital signals; and a digital signal processor configured to receive the digital signals, the digital signal processor being further configured to determine a focus error signal (FES) and a tracking error signal (TES) from the digital signals, the digital signal processor being further configured to process TES and FES through servo algorithms to produce tracking and focus control signals.

Abstract: An average servo control method is provided. A target level of at least a servo signal is first detected, which is corresponding to a present condition of the optical disc drive. The target level is then compared with a current level of the servo signal, and a average servo loop gain is adjusted based on the comparison result. A target level calibration may be performed before the gain adjustment. The target level calibration analyzes the servo signal to determine a plurality of preset target levels each corresponding to a different condition. The preset target levels and corresponding conditions are stored as a lookup table. In this way, the target level is acquired based on the lookup table and the present condition.

Abstract: A focus servo control device includes a first detector, first controller, second detector, and second controller. The first detector detects a first focus error signal. The first controller controls the objective lens based on the first focus error signal, so that a focal point of the first laser agrees with the guide layer. The second detector detects a second focus error signal. The second controller changes a relative distance between the focal point of the second laser and the focal point of the first laser, so that the focal point of the second laser agrees with a target recording/reproducing layer.

Abstract: A method for servoing when reading out a recorded holographic disk or recording in a preformatted disk includes detecting a primary signal of a reflected primary beam from a target data track of a target data layer of the disk, wherein the primary beam of radiation has a first wavelength; comparing a power measurement of the primary signal with a threshold value of power; detecting a tracking signal of a reflected tracking beam from a reference layer of the disk in an event that the power measurement of the primary signal is below the threshold value, wherein the tracking beam of radiation has a second wavelength; generating a servo error signal based upon the primary signal or the tracking signal; actuating an optical sub-system based upon either of the primary servo error signal or the tracking servo error signal such that the primary beam focuses on the target data layer.

Abstract: A focus search is performed on a mounted optical-disc recording medium once the optical-disc recording medium has been mounted in an optical disc device. The type of the mounted optical-disc recording medium is determined on the basis of results of the focus search. When a determination has been made that the mounted optical-disc recording medium is a multilayer optical-disc recording medium having three or more recording layers, a playback power is for an optical-disc recording medium being of a specification identical to the multilayer optical-disc recording medium and having one or two recording layers. A playback operation at the set playback power is used to read optical disc information from the mounted optical-disc recording medium, the optical disc information indicating the type of the mounted optical-disc recording medium.

Abstract: There is a need to prevent a possible erroneous detection of an off-track condition during recording to an optical disk. The above need can be addressed by, for example, determining an off-track condition has occurred when a light spot is located at least half-way from the track being recorded toward another track adjacent the track being recorded, and stopping a recording operation. In another example, the above need can be addressed by determining that off-track has occurred based on an output of a first off-track detector which detects that the light spot is off the track based on a wobble signal, an output of a second off-track detector which detects that the light spot is off the track based on a tracking error signal, and an output of a zero-cross detector which detects that the tracking error signal crosses zero based on an output of the tracking error signal.

Abstract: A recording apparatus, which records information in an optical recording medium, includes: a mode-lock laser unit including a saturable absorber section that applies a bias voltage, a gain section that feeds a gain current, a semiconductor laser that emits laser light used to record the information on the optical recording medium, and an external resonator; an optical modulation unit performing amplification modulation on the laser light emitted from the mode-lock laser unit; a reference signal generation unit generating a master clock signal and supplying a signal synchronized with the master clock signal to the gain section of the semiconductor laser; a recording signal generation unit generating a recoding signal based on the master clock signal; and a driving circuit generating a driving pulse used to drive the optical modulation unit based on the recording signal.

Abstract: Method and device for generating a control voltage for a position actuator of a disk drive system for displacing a lens of a pick-up unit to a given X-position. The actuator is operated by an open loop control system. First, parameters of the control system are calibrated so that the control system produces a control voltage (Va) from an input position signal (Xact_setp). Then, the control voltage is processed in a feed forward system for generating a processed control signal (Va_p) which is fed to the position actuator for displacing said lens to the X-position. A Z-value corresponding to the axial distance of the lens from a calibrated axial position and a temperature of the pick-up unit are measured. The position actuator operates according to the formula: Xdc=Va—p*K(Temp,Z)/(R(Temp)*C(Temp,Z)).

Abstract: Provided is a recording apparatus including a light irradiation and receiving unit configured to irradiate recording light for performing mark recording to a recording layer and an adjacent servo light for an adjacent track servo onto an optical disc recording medium having the recording layer through a common objective lens, and to receive reflected light from the recording layer of the adjacent servo light, a tracking mechanism configured to drive the objective lens in a tracking direction which is the disc radial direction, a tracking servo signal generation unit configured to obtain a corrected servo error signal as a servo error signal based on a light receiving signal for the adjacent servo light, and to generate a tracking servo signal using the corrected servo error signal, and a tracking driving unit configured to drive the tracking mechanism based on the tracking servo signal.

Abstract: An optical drive device includes first and second light sources, an objective lens configured to receive a first light emitted from the first light source and a second light emitted from the second light source and to irradiate both the first light and the second light to an optical disc recording medium, a first focus mechanism configured to drive the objective lens in a focus direction, a second focus mechanism configured to change collimation of the second light incident to the objective lens and changing the focusing position of the second light independently of the first light, a first focus servo control unit configured to drive the first focus mechanism, an error signal subtraction unit configured to subtract the first focus error signal from a second focus error signal, and a second focus servo control unit configured to drive the second focus mechanism.

Abstract: An apparatus and a method for compensating periodic signal in an optical disc drive are described. The control apparatus includes an amplitude processing unit, a phase processing unit, a wave generator, a first switch module and a second switch module. The amplitude processing unit processes the amplitude of the input signal based on a reference signal for generating an amplitude signal. The phase processing unit processes the phase of the input signal based on the reference signal for generating a phase signal. The first switch module switches the amplitude signal to select one of the amplitude value and a predetermined amplitude value. The second switch module switches the phase signal to select one of the phase value and a predetermined phase value. The wave generator generates a compensated wave signal based on the selected amplitude value and the selected phase value, and outputs the compensated wave signal.

Abstract: Efficient recording and reading are achieved in an optical recording medium including servo layers and recording and reading layers. The optical recording medium includes: a first servo layer having a projection and a depression for tracking control that are formed in a first spiral direction; a second servo layer having a projection and a depression for tracking control that are formed in a second spiral direction opposite to the first spiral direction; and a plurality of recording and reading layers having a flat structure with no projection and depression for tracking control. Information is recorded on each of the plurality of recording and reading layers while tracking control is performed using the first servo layer or the second servo layer.

Abstract: A disk drive determines, from eccentric amounts of individual prescribed rotation phases for one round of an optical disk 1, a rotation phase range in which a lens shift amount after tracking pulling-in of an object lens constituting an optical pickup 3 does not exceed a movable range of the object lens in a preset tracking direction, sets the rotation phase range as a tracking pulling-in range, and carries out tracking pulling-in of the optical pickup 3 while the rotation phase of the optical disk 1 is placed within the tracking pulling-in range.

Abstract: The present invention discloses a method and an apparatus for compensating astigmatism in an optical storage system. Firstly, the optical storage system focuses on an optical disc and proceeds track seeking. While track seeking, the astigmatism compensator continues adjusting and an astigmatism index signal is also measured. At last, an optimal astigmatism compensated value of the astigmatism compensator is acquired based on the measured result of the astigmatism index signal.

Abstract: An optical recording and reading method is provided in which the information necessary for recording and reading layers is quickly acquired to reduce the seek time during reading and recording. The optical recording and reading method is used for an optical recording medium that includes a plurality of recording and reading layers and a servo layer. Information is recorded on or read from the recording and reading layers by irradiating them with a recording and reading beam while the servo layer is irradiated with a servo beam to perform tracking control. When information is recorded on the recording and reading layers, control information necessary for subsequent recording and reading to be performed on the recording and reading layers is recorded on the servo layer 18. When the subsequent recording or reading is performed, the control information on the servo layer is consulted, and then the recording or reading is performed on the recording and reading layers.

Abstract: In an optical disc apparatus, when a signal to be generated corresponding to an amount of reflected light from an optical disc has a signal level below a threshold level for a period exceeding a reference period, a controller controls an actuator to move an objective lens in a direction such that a distance from the optical disc surface to the objective lens increases. The reference period may be set based on a type of the optical disc and a recording or reproducing speed of the optical disc, or based on a surface deflection of the optical disc.

Abstract: An optical disk apparatus includes an optical pickup and a signal processor. The optical pickup includes an actuator for driving an objective lens, and a detected light intensity signal output part for outputting a detected light intensity signal to the processor. The signal processor includes a servo signal generator for generating a main push-pull signal and a sub push-pull signal on the basis of the detected light intensity signal supplied from the detected light intensity signal output part, a signal generator for generating a differential push-pull signal and a lens error signal by conducting addition/subtraction on the main push-pull signal and the sub push-pull signal, and a tracking offset correction signal generator which is input with the lens error signal to output a tracking offset correction signal. The differential push-pull signal correction is conducted by conducting addition/subtraction between the differential push-pull signal and the tracking offset correction signal.

Abstract: An information reproducing apparatus has a medium with a linear tracking mark extending in a scanning direction and a linear data mark extending in a direction orthogonal to the scanning direction. A light control unit irradiates the data mark with a first near-field light polarized in the scanning direction and irradiates the tracking mark with a second near-field light polarized in the direction orthogonal to the scanning direction. A detector detects light scattered by the data mark and the tracking mark irradiated with the first near-field light and the second near-field light, respectively. A signal processing unit processes a first output signal from the detector corresponding to the detected light scattered by the data mark and processes a second output signal from the detector corresponding to the detected light scattered by the tracking mark.

Abstract: An optical disk apparatus according to the present invention includes: a controller 111, which receives an instruction that a layer-to-layer jump be performed from a current layer to a target layer; a layer-to-layer jump control section 146, which adjusts a spherical aberration correction value to the target layer and then gets the layer-to-layer jump attempted; a decision section 146 for determining whether the layer-to-layer jump has been carried out successfully; and a layer determining section 146 for determining, if the focus position has been set on a non-target storage layer as a result of the layer-to-layer jump, where the non-target storage layer is located in the optical disk. The layer-to-layer jump control section 146 shifts the focus position of the light beam from that non-target storage layer to the target layer by reference to information indicating which of the multiple storage layers the non-target storage layer is.

Abstract: A simple circuit configuration allows an optical disc apparatus to reduce a problem of sound skips occurring due to damage on an optical disc. To this end, an LPF extracts a low-frequency component from a tracking actuator drive signal obtained by a tracking actuator driver. When the optical disc apparatus reads and writes information to and from the optical disc, a sled drive signal supplier outputs a sled pulse signal, as a drive signal for a sled motor, for a set-up predetermined time within each interval of a predetermined length, the sled pulse signal having a level corresponding to a level of the low-frequency component obtained by the LPF. On the other occasions, the sled drive signal supplier outputs the low-frequency component obtained by the LPF as the drive signal for the sled motor.

Abstract: A device for detecting wobbles on an optical disc is provided, where the device is utilized for generating a wobble signal according to a plurality of detection signals. The device includes an analog signal processing circuit, a pair of analog-to-digital converters (ADCs), and a digital signal processing circuit. The analog signal processing circuit is arranged to perform analog signal processing on the detection signals to generate a plurality of output signals. In addition, the pair of ADCs are arranged to digitalize the output signals to generate a plurality of digital values. Additionally, the digital signal processing circuit is arranged to perform digital signal processing on the digital values and generate an arithmetic output, where the arithmetic output is utilized for generating the wobble signal or utilized as the wobble signal. An associated method for detecting wobbles on an optical disc is further provided.

Abstract: A circuit for generating a tracking error signal is provided. The circuit includes a digitizing circuit, a short signal removing circuit and phase comparator. The digitizing circuit receives first and second pick-up signals outputted from a pick-up head, and respectively compares the first and the second pick-up signals with a reference signal to obtain a first digital signal and a second digital signal. The short signal removing circuit is used for removing pulses in the first and the second digital signals, wherein the pulse width of the removed pulses are shorter than a preset time, and the first and second digital without the removed pulses are respectively served as a first determining signal and a second determining signal. The phase comparator receives the first determining signal and the second determining signal for outputting the tracking error signal according to a phase difference between the first and the second determining signals.

Abstract: The present invention can properly correct spherical aberration. An optical disk device (10) displaces an objective lens (18) so that the objective lens is displaced to a reference lens position as a reference. The optical disk device (10) controls an information light condensing point changing mechanism (55) so as to adjust the focus (FM) of an information light beam (LM) to a recording depth (X) at which the information light beam (LM) is to be applied in a state of the objective lens (18) being placed at a reference lens position (SL). The optical disk device (10) controls a servo light condensing point changing mechanism (35) so as to adjust the focus (FS) of a servo light beam (LS) to a servo layer (104) in the state of the objective lens (18) being placed at the reference lens position (SL).

Abstract: An information storage device includes an information recording medium, at least a single light source that emits laser light, an illuminating unit that illuminates substantially the same position of the information recording medium with two light rays generated from the laser light, in different directions, a light detecting unit that detects reflection light of the two light rays reflected from the information recording medium and outputs a detection signal, an operation unit that calculates position error information of the information recording medium based on the detection signal; and, a driving device that changes the position of the information recording medium based on the position error information.

Abstract: A method of recognizing a track pitch of an optical disk, adapted for an optical disk player, is provided. The method includes the steps of driving an optical pickup head to a predetermined position, so that the optical pickup head and the spindle motor are a predetermined distance apart, reading a data sector address, and recognizing the magnitude of the track pitch of the optical disk according to the value of the data sector address.

Abstract: An optical pickup apparatus comprising: a diffraction grating that a laser beam enters, the diffraction grating being configured to generate a main beam that is 0th order light and sub-beams that are +1st order diffracted light and ?1st order diffracted light; an objective lens configured to focus the main beam and the sub-beams onto a signal recording layer; a main-beam light-receiving portion that the main beam reflected by the signal recording layer is applied to; and sub-beam light-receiving portions that the sub-beams reflected by the signal recording layer are respectively applied to, each light-receiving area of the sub-beam light-receiving portions being smaller than a light-receiving area of the main-beam light-receiving portion.

Abstract: A circuit for generating a tracking error signal is provided. The circuit includes a digitizing circuit, a short signal removing circuit and phase comparator. The digitizing circuit receives first and second pick-up signals outputted from a pick-up head, and respectively compares the first and the second pick-up signals with a reference signal to obtain a first digital signal and a second digital signal. The short signal removing circuit is used for removing pulses in the first and the second digital signals, wherein the pulse width of the removed pulses are shorter than a preset time, and the first and second digital without the removed pulses are respectively served as a first determining signal and a second determining signal. The phase comparator receives the first determining signal and the second determining signal for outputting the tracking error signal according to a phase difference between the first and the second determining signals.

Abstract: A guide-layer separated optical disk which includes a guide layer having a guide structure whose tracking guide tracks are divided into areas by discontinuous portions, the areas each having concentric guide tracks of arc shape at a regular track pitch, the guide tracks in adjoining two of the areas across one of the discontinuous portions deviating from each other in a radial direction of the disk by ¼ the track pitch. An optical disk drive apparatus and a tracking control method in which a servo optical system switches the tracking center of the irradiation spot of a first laser beam between on the guide tracks and in between the guide tracks alternately each time the irradiation spot passes two of the discontinuous portions.

Abstract: Method and device for generating a control voltage for a position actuator of a disk drive system for displacing a lens of a pick-up unit to a given X-position. The actuator is operated by an open loop control system. First, parameters of the control system are calibrated so that the control system produces a control voltage (Va) from an input position signal (Xact setp). Then, the control voltage is processed in a feed forward system for generating a processed control signal (Va_p) which is fed to the position actuator for displacing said lens to the X-position. A Z-value corresponding to the axial distance of the lens from a calibrated axial position and a temperature of the pick-up unit are measured. The position actuator operates according to the formula: Xdc=Va_p*K(Temp,Z)/(R(Temp)*C(Temp,Z)) in which: Xdc=position signal for said given position Va_p=Va processed K=property of ‘actuator’ 21: Newton/Ampere R=resistance of ‘actuator’ coil C=Spring constant in Newton/meter.

Abstract: There is a need to accurately lock focus of a laser beam onto a target data layer of a multilayer optical disc. The above need can be addressed by, for example, performing a focus lock operation after a spherical aberration correction amount is set in such a way as to make smaller the ratio of the focus error signal waveform amplitude at the data layer adjacent to a target data layer through which a laser beam passes earlier than through the target data layer to the focus error signal waveform amplitude at the target data layer than that when the spherical aberration correction amount is set so as to be optimal for the target data layer.

Abstract: The disclosure discloses a compensation method in a radial direction on a label side of an optical disc. An optical disc is inserted into an optical disk drive. The data side of the optical disc is divided into at least one compensation area. An optical pick-up head (OPU) is moved from inner to outer rings by simulating a writing process. The OPU is moved to some pre-determined points and radial-directional compensation is performed to obtain radial-directional voltage gains at the pre-determined points. The voltage gains are recorded. The label side of an optical disc is inserted into the optical disk drive. The simulated track number is calculated on the basis of the required moving distance for the OPU to write pattern on the label side. The OPU is moved to write the label side by a radial-directional lens driving voltage compensated with a gain obtained from a compensation formula.

Abstract: An optical disk apparatus includes a light focusing element arranged to face a disk and to focus light emitted from a light source on the disk, an actuator to move the light focusing element towards and away from the disk according to an actuator driving voltage, a light intensity detection unit to detect an intensity of light reflected by the light focusing element and generate a gap error signal based on the detected intensity, a servo unit to generate the actuator driving voltage and a predetermined threshold voltage based on the gap error signal generated by the light intensity detection unit and to provide the actuator driving voltage to the actuator, a distance detection unit to detect a first distance at which the actuator driving voltage is maintained when the threshold voltage is detected using the gap error signal and to detect a second distance at which a gap between the light focusing element and the disk is shorter than the first distance and at which a gap servo operation is started based on the

Abstract: A method of determining a disk type of an optical disk is provided to comprise steps of: using a first light path for forming an incident beam; moving an objective lens system corresponding to the first light path from a start position towards the optical disk; receiving a sensor output signal during the movement of the objective lens system, wherein the sensor output signal includes a central aperture signal; determining the disk type of the optical disk according to the central aperture signal.

Abstract: A circuit for generating a tracking error signal is provided. The circuit includes a digitized circuit, a short signal removing circuit and phase comparator. The digitized circuit receives first and second pick-up signals outputted from a pick-up head, and respectively compares the first and the second pick-up signals with a reference signal to obtain a first digital signal and a second digital signal. The short signal removing circuit is used for removing pulses in the first and the second digital signals, wherein the pulse width of the removed pulses are shorter than a preset time, and the first and second digital without the removed pulses are respectively served as a first determining signal and a second determining signal. The phase comparator receives the first determining signal and the second determining signal for outputting the tracking error signal according to a phase difference between the first and the second determining signals.

Abstract: A driving device includes an optical pickup unit that irradiates a disc having a plurality of recording surfaces with a laser beam used for recording or reproducing information, and a generating unit that generates a focus control signal used for controlling a focus state of the laser beam emitted from the optical pickup unit on the basis of a focus error signal. The generating unit includes level detector that detects a level of the focus error signal, an offset generator that generates an offset signal used for performing focus jumping from one of the plurality of recording surfaces to another one of the plurality of recording surfaces in accordance with the focus error signal, and a switcher that switches a polarity of the focus control signal by comparing the level of the focus error signal of the level detector with a threshold value.

Abstract: The present techniques provide methods and systems for alignment of a read head with data tracks on an optical data disk. In embodiments, a multi-pixel detector that is segmented into multiple areas, or detector segments, may be used to detect a pattern in the light reflected from an optical data disk. The detector system may then combine the quantized values from each of the detector segments mathematically to determine the alignment of the read head with a target data track. If the read head drifts to one side or the other, detectors to the side of a center detector may start to pick up energy from the adjacent tracks. If this energy is continuously summed for the detectors on each side, the read head may be centered by balancing the sums from the detectors on each side.

Abstract: A recording apparatus, which records information in an optical recording medium, includes: a mode-lock laser unit including a saturable absorber section that applies a bias voltage, a gain section that feeds a gain current, a semiconductor laser that emits laser light used to record the information on the optical recording medium, and an external resonator; an optical modulation unit performing amplification modulation on the laser light emitted from the mode-lock laser unit; a reference signal generation unit generating a master clock signal and supplying a signal synchronized with the master clock signal to the gain section of the semiconductor laser; a recording signal generation unit generating a recoding signal based on the master clock signal; and a driving circuit generating a driving pulse used to drive the optical modulation unit based on the recording signal.