Abstract: An information recording and/or reproducing apparatus using a removable disk-shaped optical recording medium (51) is provided which includes a storage unit (31) to store an axial-runout amount in a predetermined radial position on the disk-shaped optical recording medium (51) being rotated, a near-field light projector (7) provided to condense a light beam emitted from a light source (3) and which projects the condensed light beam as near-field light when located in a field near the information recording surface of the disk-shaped optical recording medium (51), a first controller (30) which multiplies an axial-runout amount read from the storage unit (31) by a predetermined gain to generate a control signal and controls the near-field light projector (7) to follow the axial-runout amount of the disk-shaped optical recording medium (51), and a second controller (40) to control the near-field light projector (7) on the basis of the linear characteristic of the return-light amount of the near-field light to keep

Abstract: An optical disc device recording method, which includes determining whether or not a recording process that records information on a label surface of an optical disc has failed, detecting a recording failure position at which the recording process has failed when the determining step determines the recording process has failed, and resuming the recording process from the detected recording failure position.

Abstract: The invention provides an optical disk device that has a laser unit including a first objective lens and a second objective lens. A numerical aperture of the first objective lens is different from a numerical aperture of the second objective lens. The optical disk device has a first focus driver that detects a first voltage value indicating the value of a driving voltage to drive the first objective lens when light beams are irradiated onto the surface of an optical disk via the first objective lens and a focus is achieved. The optical disk device has a second focus driver that detects a second voltage value indicating the value of a driving voltage to drive the second objective lens when light beams are irradiated onto the recording surface of said optical disk via the second objective lens and a focus is achieved. The optical disk device has a controller that discriminates the type of an optical disk, based on a difference between the first voltage value and the second voltage value.

Abstract: A system and method for recording and reproducing holographic interferogram with servos. A servo process is provided by the system and method to continuously record a holographic interferogram in a holographic recording medium with servo trace layers. Also, by the servo process, the intensity distribution of a reference beam is monitored, which is reflected by a reflecting mirror disposed on the other side of the holographic recording medium. By analyzing the distribution, one can adjust the distance and the incidence angle between the reflection mirror and the reference beam. Moreover, a plurality of servo tracks on different layers are provided for recording the holographic interferogram on different layers of holographic recording medium.

Abstract: An optical head device may include a twin laser light source which is integrally provided with a first laser beam emitting element and a second laser beam emitting element, a light receiving element, and an optical system including an objective lens for converging a laser beam on an optical recording medium. The optical system is provided with a detection lens structured of a toric lens. The toric lens applies an astigmatic difference caused by a toric face to the one of the return light beams, and the toric lens applies the other of the return light beams an astigmatic difference caused by a toric face and astigmatism composed of astigmatism and curvature of image field caused by passing off-axis position to coincide a focusing position of the first laser beam with that of the second laser beam.

Abstract: Rotation synchronization detection means is provided which detects a specified rotational phase having a period of one revolution of an optical disk. An output of the rotation synchronization detection means is synchronized with an output of rotation phase detection means for detecting a rotation phase on the basis of a FG signal and thereafter, information of surface vibration component and eccentricity component is memorized in memories before a sleep process in accordance with the output of the rotation phase detection means or a timing until jump is determined in accordance with the output of the rotation phase detection means and during recovery from the sleep status of stopping the disk once, the output of the rotation synchronization detection means is again synchronized with the output of the rotation phase detection means adapted to detect the rotation phase on the basis of the FG signal.

Abstract: An optical disk apparatus includes an optical pickup head (PUH) which outputs a laser beam through an objective lens. When a control unit receives an instruction to halt data read-out from an optical disk, the control unit moves the PUH to a predetermined position, stores a focus driving voltage corresponding to a position of the objective lens in a memory unit, and halts the output of the laser beam from the PUH. When the control unit receives an instruction to resume the data read-out, the control unit resumes the output of the laser beam from the PUH, starts a focus search on the basis of the focus driving voltage that is stored in the memory unit, moves the objective lens in a direction toward the optical disk, and achieves focus adjustment.

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: In the first and second light-receiving regions equally divided into two in parallel with the track of the optical disc, the reflected light received from the optical disk is converted into electric signals and fed out by individual light-receiving regions. Then, the light-receiving ratio indicating the ratio of amounts of received light is calculated from the amplitude of the electric signal generated in the first light-receiving region and the amplitude of the electric signal generated in the second light-receiving region. Then, it is determined whether or not an absolute value of the light-receiving ratio is larger than a predetermined vale. When the absolute value is larger, the movement of the objective lens in a radial direction is corrected by incorporating a predetermined correction value.

Abstract: In a particular type of high-density optical recording systems, a solid immersion lens (SIL) is used in the objective system to focus a radiation beam onto an information layer of an optical record carrier. The distance between the exit surface of the SIL and the entrance surface of the record carrier is typically 25 nm to allow evanescent coupling of the radiation from the SIL to the optical record carrier for a system using a blue laser as radiation source. Such a system is also called a near-field system, deriving its name from the near field formed by the evanescent wave at the exit face of the SIL. A suitable gap signal, representing the width of the gap, is used to control the width of the gap during operation of the system. Tolerances in the optical elements and opto-mechanical components of the optical system of the optical recording system can lead to an offset in the position of the focus point of the objective system.

Abstract: To obtain optimum conditions for writing data on the disc. Provided is an optical disc drive for writing/reading data on/from a loaded optical disc medium comprising: a pickup for writing/reading data on/from the optical disc medium using laser light; and a controller for controlling an operation of the optical disc drive. The controller judges whether the loaded optical disc medium is unrecorded; records a first piece of data on a test area of the optical disc medium in a case where the loaded optical disc medium is judged to be unrecorded; determines optimum output power for recording the data by reproducing the first piece of data; records a second piece of data on the test write area using the determined optimum output power; and adjusts focus balance by reproducing the second piece of data.

Abstract: A focus servo system with a focus close algorithm is disclosed. The focus close algorithm provides a bias control effort to the focus servo system when focus is closed. A method of closing focus includes positioning an optical pick-up unit at a first position away from an optical medium, moving the optical pick-up unit towards a second position by altering a focus control effort, monitoring a sum signal obtained from signals received from the optical pick-up unit, and setting the bias control effort to the focus control effort when a closure criteria is satisfied. In some embodiments, the closure criteria includes that a sum signal exceeds a threshold value. In some embodiments, the closure criteria includes that a focus error signal is below a FES threshold.

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 for detecting an oscillation of a servo controller of an optical disk is provided. An oscillation detector, electrically coupled to the servo controller of the optical disk, is provided and is configured to receive an error signal associated with the servo controller. The oscillation detector is further configured to compare an amplitude, a width and a period of the error signal with a reference amplitude, a reference width and reference period to determine if an oscillation is present in the error signal. Related methods and computer program products are provided.

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: An optical disc apparatus is disclosed that comprises a jitter value detecting circuit that detects a jitter value based on the signal read out from an optical disc; and a defocus value setting circuit that adjusts a defocus value used for moving an objective lens along the direction of a light axis when focusing of the objective lens to the optical disc is performed, based on the signal that has gone through the jitter value detecting circuit, and causes a defocus adjustment to be made based on the defocus value.

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 driver IC 1 has a bias terminal 20a via which a bias voltage fed from a microcomputer 2 to drive and control a loading motor 4 is fed in and a bias terminal 20b via which a bias voltage fed from a DSP 3 to drive and control a focus coil 5, a tracking coil 6, a sled motor 7, and a spindle motor 8 is fed in.

Abstract: An information recording system for recording information on an optical disc using a reference clock signal generated based on a push-pull signal including a wobble frequency component, the system includes an amplitude obtaining unit for obtaining an amplitude value of the push-pull signal, a threshold calculation unit for calculating a displacement threshold of the push-pull signal based on the amplitude value obtained by the amplitude obtaining unit, and a noise reduction unit for generating a corrected push-pull signal by correcting the push-pull signal such that a displacement exceeding the displacement threshold is reduced. The reference clock signal is generated based on the corrected push-pull signal generated by the noise reduction unit.

Abstract: An optical reading/writing apparatus has an optical head that includes a collimator and a lens. For efficient and reliable focusing control for writing an empty optical disk, calibration of focus offset and spherical aberration is executed by setting a boundary and performing data-reading in an OPC area only with combinations of focus offset and spherical aberration within the boundary. Accordingly, an optimum combination of focus offset and spherical aberration is determined for focusing compensation in subsequent writing operation of the empty disk.

Abstract: A method for setting a layer-jump point on a multilayer optical disc in an optical drive for accessing the multilayer optical disc. First, a magnetic-pole cycle value is accumulated. Next, a lag control signal of the optical drive is detected to record the magnetic-pole cycle value as a magnetic-pole basic value. Then, a magnetic-pole offset value is generated according to a phase difference between the lag control signal and an oscillating position of the multilayer optical disc. Finally, a layer-jump-point reference value, according to which the optical drive moves from one layer of the multilayer optical disc to another layer thereof to access data, is set by adding the magnetic-pole basic value to the magnetic-pole offset value.

Abstract: A method for determining a kind of optical recording medium includes: performing focus searching and track searching on an optical recording medium; and determining a kind of optical recording medium according to an optical signal generated by the focus searching and an optical signal generated by the track searching.

Abstract: An optical scanning device for scanning a record carrier (22), the record carrier has an outer face (24) and the optical scanning device comprises a radiation source system (2) arranged to generate a radiation beam; an objective system (20) having an exit face (76) and which is arranged between the radiation source system and the record carrier and provides for evanescent coupling of the radiation across a gap between the exit face of the objective system and the outer face of the record carrier; and a radiation detector arrangement for detecting radiation after interaction with the record carrier. The radiation detector arrangement is arranged to produce a tilt error signals (?, ?) representing a tilt misalignment between the exit face of the objective system and the outer face of the record carrier.

Abstract: A method for controlling a stepper motor in an optical disc system, comprising the steps of (A) measuring a static offset of a center error signal, (B) measuring a maximum value, minimum value and an average value of the center error signal in response to rotating the optical disc, (C) computing one or more upper threshold values and one or more lower threshold values of the center error signal, (D) sampling the center error signal, (E) comparing the center error signal to the one or more upper threshold values and to the one or more lower threshold values and (F) computing a control output to control the stepper motor in response to comparing the center error signal to the one or more upper and lower threshold values.

Abstract: Disclosed is a method of preventing optical recording media from being fractured and apparatus thereof, which enable to prevent an optical disc of an optical disc drive from being fractured due to a crack. The method and apparatus comprise: detecting a first tracking error signal outputted from a data recording/reproducing apparatus when the optical recording media are rotated at a first speed; detecting a second tracking error signal outputted from the data recording/reproducing apparatus when the optical recording media are rotated at a second speed; determining whether or not the crack on the optical disc exists on the basis of the first tracking error signal and the second tracking error signal; and stopping an operation of the data recording/reproducing apparatus when the optical recording media have the crack.

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: Calibration of a focus offset in an optical drive. A calibration pattern, comprising a plurality of marked areas, is marked upon a medium. A user input is received, identifying a perceived darkest marked area of the calibration pattern. The focus offset is determined corresponding to the perceived darkest marked area.

Abstract: The present invention relates to a method of detecting a header region for a writeable optical carrier. The method initially obtains a data signal (RF) from the optical carrier, and performs a low pass filtering the data signal (RF) for a pre-determined time constant. Subsequently, there is performed a comparison between the low pass filtered data signal (LPF_RF) and a dynamically determined threshold level (RF_th), whereby a positive indication of a header region (I, II, III) is obtained, if the low pass filtered data signal (LPF_RF) is above the dynamically determined threshold level (RF_th). In an advantageous embodiment, there is further performed a comparison of a polarity signal (DPII) to a previous polarity signal (DPI) so as to provide an indication of a land-groove transition. The present invention provides a simple and robust method of detection and header region and possibly a land-groove transition compared to the hitherto known solutions.

Abstract: This invention relates to an optical disc assembly capable of receiving an insert upon which an analyte of interest may be disposed. The optical disc assembly can be read by an optical disc reader, such as by a standard CD or DVD reader, and the analyte disposed on the insert can be detected by the optical disc reader. The optical disc assembly may have one or more data layer in which operational information or assay information is encoded. Hologram may be used to encode operational information or assay information.

Abstract: An information reproducing apparatus has a light source for generating linearly polarized light, a medium having linear marks disposed in overlapping relation to one another, and an optical head disposed between the light source and the medium and having a fine aperture. A polarized light control portion in the light source controls the linearly polarized light to pass through the fine aperture of the optical head to generate near-field light having a preselected polarization direction and to irradiate the linear marks of the medium with the near-field light so that the preselected polarization direction of the near-field light is orthogonal to a longitudinal axis of each of the linear marks. A detector detects light scattered by the linear mark irradiated with the near-field light.

Abstract: An optical pickup is provided for preventing an objective lens from colliding with an optical recording medium at the stage of initial adjustments. The optical pickup device comprises a servo circuit, and a lens driver for driving an objective lens. In the servo circuit, a drive signal generator supplies the lens driver with one of a first focus drive signal for moving the objective lens in a direction closer to an information recording layer, and a second focus drive signal for moving the objective lens in a direction away from the information recording layer. A controller in a timing generator switches a signal supplied to the lens driver from the first focus drive signal to the second focus drive signal when the level changes by a predetermined range or more in a servo signal which is generated during a period in which the first focus drive signal is being supplied to the lens driver.

Abstract: In an optical disk recording and reproducing device which uses an optical disk having at least a first recording layer and a second recording layer, a thickness of a spacer section between the first recording layer and the second recording layer is measured, an amount of defocus with respect to the second recording layer is set based on the measured spacer thickness, and a focus servo operation is performed for focusing the laser light irradiated from an optical pickup device on the second recording layer.

Abstract: An intelligent layer jump method applied when an optical disc drive accesses a disc. The disc has a central reference point, at least a first recoding layer and a second recoding layer. The first recoding layer has a plurality of first tracks, while the second recoding layer has a plurality of second tracks. Firstly, a laser beam of the optical disc drive is focused on the first recoding layer to form a focal point and obtain an original position. Then, the relative position between an original position and a target position positioned on the second recoding layer are compared to determine a layer jump and track seeking path of the focal point. Lastly, the focal point is shifted from the original position to the target position according to the predetermined layer jump and track seeking path.

Abstract: An apparatus and method for layer jump braking control is disclosed. The apparatus is applied to an optical drive and generates a non-fixed braking signal according to a focusing error signal. The non-fixed braking signal is provided to a driver for outputting a corresponding driving force, thereby controlling a pick up head of the optical drive to perform a layer jump braking process. By using the non-fixed braking signal, the disadvantage of the conventional fixed braking signal, which cannot adapt to variations of optical disks and is subject to layer jump failure, can be avoided.

Abstract: The present invention discloses a method and apparatus of seek end polarity detection for an optical disk drive. The method comprises the steps of providing a horizontal level between the peak and the trough of the tracking error signal when the tracking error signal is used to determine the polarity of the tracking error; and determining the tracking error polarity by examining whether or not the adjacent waveform level is smaller or larger than the horizontal level after the tracking error signal passes through the horizontal level.

Abstract: A focusing control method on a light-scribed disc firstly focuses a base voltage on a label side. Light summed signals are detected and recorded. The biggest light summed signal is determined, and subtracts the light summed signal of each spoke to form an error signal. The error signal is multiplied by a gain to form a gain signal. The base voltage adds the gain signal to form an upper referring voltage, and subtracts the gain signal to form a lower referring voltage. The label side is focused with the upper referring voltage and the lower referring voltage respectively. The light summed signals are detected and recorded, to determine the biggest light summed signal of each spoke. According to the corresponding voltage of the biggest light summed signals, a focusing control curve is approached to determine optimum parameters.

Abstract: A method and apparatus for adjusting tracking error balance in an optical disk reproducing apparatus are provided. The method includes pre-setting a tracking error balance for an optical recording medium and adjusting the tracking error balance during reproduction of data from the optical recording medium.

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: In an optical disc device of the present invention, time differences among the focus error signal corresponding to the surface of the optical disc, the focus error signal corresponding to the first reflection layer, and the focus error signal corresponding to the second reflection layer, all of which are obtained through the light receiving element when a relative distance between the objective lens and the optical disc is linearly changed in a focus search of the optical disc are measured. The thickness of the cover layer from the surface of the optical disc to the first reflection layer and the thickness of a cover layer from the surface of the optical disc to the second reflection layer are detected on the basis of these time differences.

Abstract: A method used in an optical storage device having a pickup head. The pickup head includes an object lens, a first and a second light source. The object lens focuses the laser light generated by the first or the second light source onto a first or a second focal point. A driving control effort is used to change the location of the object lens. The method includes the following steps: providing the driving control effort to move the object lens; measuring a first parameter when the first focal point passes through a predetermined layer of an optical disc; measuring a second parameter when the second focal point passes through the predetermined layer of the optical disc; and (d) determining the relationship between the difference of object lens location and the driving control effort according to the predetermined distance, the first parameter, and the second parameter.

Abstract: The present invention provides highly reliable PLL without influence of variations in amplitude of a reproduced signal or variations in inclination of an edge. An information-reproducing apparatus according to the present invention includes a unit for detecting a phase difference between a reproduced signal and a reproducing clock signal, a PLL circuit for regulating a frequency of the reproducing clock signal to compensate for the detected phase difference, a unit for detecting a state of the PLL circuit, and a unit for regulating a loop gain of the PLL circuit corresponding to the detected state.

Abstract: An optical disc drive includes: a light source; a focusing section; a focus shifting section for shifting the focal point of light by changing the position of the focusing section perpendicularly to a data storage layer of a given optical disc in accordance with a control signal; a light receiving section for receiving, at multiple areas, the light reflected from the data storage layer and generating light quantity signals; a signal generating section for generating a focus error signal based on the light quantity signals; and a control section for generating the control signal responsive to the focus error signal such that the focal point is transferred to a focus controllable range. The control section generates the control signal such that the focal point is decelerated at a first acceleration and then at a second acceleration. The absolute value of the second acceleration is smaller than that of the first acceleration.

Abstract: An electronic apparatus with level detecting capability has an electronic component, a light-sensing device for sensing light, a light source for emitting light onto the light-sensing device, a light blocker for blocking light emitted by the light source from projecting onto the light-sensing device when the electronic component is tilted and has a tilt angle within a predetermined range, and a control circuit electrically connected to the light-sensing device for controlling the electronic component to selectively operate in one of a plurality of operating modes according to the intensity of light received by the light-sensing device.

Abstract: A real-time wobble detector and an adaptive layer distance balancing calculator are added in a layer jump control device of a high-speed optical drive to solve failure and instability caused by the wobble effect of the optical drive during layer jump. A layer jump control method of the optical drive is also provided.

Abstract: An optical pickup apparatus for shining light on an optical disk having two recording layers and for detecting reflected light from the optical disk includes a light source, an optical system situated on a path of a light beam returning from the optical disk inclusive of light reflected by a first recording layer of the optical disk and light reflected by a second recording layer of the optical disk, the optical system including a light condensing optical unit to turn the returning light beam into a condensing light beam, and a light beam regulating unit to extract from the condensing light beam a partial light beam corresponding to part of a cross section of the condensing light beam, and one or more photo detectors, situated between a position where the light reflected by the first recording layer contained in the partial light beam is condensed and a position where the light reflected by the second recording layer contained in the partial light beam is condensed, the one or more photo detectors having a fi

Abstract: A Bemf detect circuit is configured for modeling Bemf error via calculation of time correlations associated with two or more different non-calibrated sense resistor gain values to derive a calibrated sense resistor gain value. A method is provided for calibrating a Bemf detector circuit by setting a sense resistor gain to a plurality of different gain values, observing Bemf sample values for each of the gain values, and deriving a calibrated gain value by non-iteratively modeling the relationship between the gain values and the associated Bemf sample values.

Abstract: An apparatus and method of controlling tracking in a disc drive using a tracking actuator, a feed motor, and an objective lens, including monitoring whether the tracking actuator deviates from a dynamic range based on a signal controlling the feed motor when tracking is performed; and returning the objective lens connected to the tracking actuator to a neutral point when it is determined that the tracking actuator deviates from the dynamic range.

Abstract: The magnitude (Ga) of an impact applied to a lens holder is constantly monitored based on an output of an impact sensor. When it is determined that Ga exceeds Gth, focus servo is released, and the lens holder is provided with a force to make it move away from a disk. Upon recheck of Ga, when it is determined that Ga is now equal to or less than Gth, the force having been provided to the lens holder is cancelled, and the focus servo is resumed.

Abstract: A weighted defect estimating apparatus and a related method for determining a defect estimation value are disclosed. The weighted defect detecting apparatus includes: a defect detecting unit for generating a defect value when a defect in a predetermined region of an optical disc is detected; a weighting circuit, electrically connected to the defect detecting unit, to generate a weighted defect value according to the defect value and a weighting factor corresponding to a location of the defect on the optical disc; and a computing module, electrically connected to the weighting circuit, for computing the defect estimation value according to a plurality of weighted defect values corresponding to the predetermined region.

Abstract: An optical disc reading and reproducing apparatus includes reading means for reading data recorded on an optical disc by applying laser light through an objective lens and detecting its reflected light, focus control means for performing focus control for moving the objective lens based on a focus error signal indicating an amount of deviation of a focusing position, focus bias adjustment means for adjusting a focus bias used in the focus control to a voltage in which amplitude of an acquired RF signal is maximized, and detection means for detecting that the amplitude becomes smaller than a predetermined threshold level. The focus bias adjustment means samples the RF signal and acquires the amplitude, sets the focus bias to the amount in which the amplitude of the RF signal is maximized, and stops sampling of the RF signal when the amplitude is detected to be smaller than the predetermined threshold level.