Abstract: A laser driving circuit employing a recording compensation circuit configured to generate a light emission timing of a laser on the basis of recorded data and a recording clock signal which are supplied to the recording compensation circuit includes: a phase synchronization circuit; a skew determination circuit; and a data latching circuit.

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: Disclosed is an optical disk barcode forming method wherein, as information to be barcoded, position information for piracy prevention, which is a form of ID, is coded as a barcode and is recorded by laser trimming on a reflective film in a PCA area of an optical disk. When playing back the thus manufactured optical disk on a reproduction apparatus, the barcode data can be played back using the same optical pickup.

Abstract: According to one embodiment, a power management module of a storage device executes a process of stopping rotation of a disk storage medium by selectively using one of a first mode of stopping the rotation of the disk storage medium on condition that a media access command is not received during a predetermined time from last reception of a media access command, and a second mode of stopping the rotation of the disk storage medium on condition that a media access command which causes access to the disk storage medium is not received during a predetermined time from last reception of a media access command which causes access to the disk storage medium. In addition, the power management module executes a process of starting the rotation of the disk storage medium by selectively using one of a third mode and a fourth mode.

Abstract: A recording and reproducing apparatus includes an access display unit of a hard disk and a failure diagnosis unit to carry out a failure diagnosis by using error information of data reproduced from the hard disk, in which either a video recorded in the hard disk is displayed on the access display unit or an access on the reproduction is displayed thereon, and a warning content obtained from a diagnostic result of the hard disk is displayed after the access is completed.

Abstract: Provided are an optical pick up and an optical component used for the optical pickup which are capable of preventing or restraining occurrence of deviation and unbalance which are caused by assembly errors during manufacturing of optical components, a temperature variation or the like. The optical pickup comprises a laser, a polarization changeover element for changing over a direction of polarization of an optical beam emitted from the laser, a beam splitting element for splitting the laser beam into a plurality of optical paths in accordance with a direction of a polarization, a plurality of objective lenses for focusing laser beams onto a recording layer of the optical disc, a rise-up mirror, and a plurality of coupling lenses arranged respectively intermediate of the plurality of optical paths led to the plurality of objective lenses.

Abstract: A pickup device includes an irradiation optical system including an object lens for focusing light flux on a track of a recording surface of an optical recording media having a plurality of recording layers stacked while a spacer layer is interposed between the recording layers to form a spot and a detection optical system including an photo detector having a plurality of light receiving parts for receiving returning light reflected from the spot through the object lens to perform photoelectric conversion. The pickup device controls a position of the object leans according to an electrical signal calculated from outputs of the light receiving parts.

Abstract: Aspects of the disclosure provide a method to efficiently calibrate parameters of a memory reading device. The method can include defining two or more value sets for the parameters of the memory reading device to read a memory medium, reading the memory medium with the parameters set respectively at the value sets, receiving performance signals corresponding to operation of the memory reading device having the parameters set at the value sets, respectively, and setting the parameters of the memory reading device for reading the memory medium based on the performance signals.

Abstract: A method of recording marks onto an optical disc, the optical disc comprising an information layer, by irradiating the information layer by a pulsed radiation beam, a mark (I3 . . . I14) having a time length of nT, n representing an integer larger than one and T representing the length of one period of a reference clock, being recorded by a sequence comprising m write pulses separated by cooling periods, the write pulses within the sequence being allowed to have different time lengths, the write pulses comprised in sequences corresponding to marks of different time lengths being allowed to have different lengths, m being an integer number given by Floor(n/?), where Floor(n/?) defines the largest integer smaller than n/?, wherein a is an integer number larger than or equal to 2. The method characterized by modifying at least the sequence comprising the longest write pulse such that the longest write pulse is replaced by two write pulses.

Abstract: The present invention relates to a clamping apparatus for a disc player which is able to accurately release a clamper from a turntable while improving miniaturization and thinning.

Abstract: A reading devices suppresses deterioration of the recording marks caused by increasing the output laser power to compensate for a drop in the S/N ratio when reading at a high speed information recorded to a high density recording medium. To read information recorded to an optical data recording medium that is written and read using a laser beam output from a semiconductor laser, the reading method modulates a high frequency current on the drive current of the semiconductor laser to output the laser beam, and changes the light modulation rate according to the selected linear velocity used for reading. The light modulation rate is the ratio Pp/Pave between the peak power Pp and the average read power Pave of the light intensity of the high frequency modulated laser beam.

Abstract: A method for enhancing the optical initializing operation comprises: sending a radial error signal from an optical pick-up unit to a radial error signal calibration unit; sending the radial error signal from the optical pick-up unit to an offset adjuster; sending a calibrated radial error signal from the radial error signal calibration unit to the offset adjuster and a gain adjuster; sending a radial actuator (RA) signal from the radial error signal calibration unit to activate a radial actuator during an initialization or a period for calculating RE signal calibrating parameters.

Abstract: A quarter-wave plate includes a base member including a ridge and trough periodic structure with a structural period of ?min/2<P<?min arranged on one side of the base member, where ?min is the minimum wavelength among the wavelengths of a plurality of light fluxes which pass the quarter-wave plate. In the quarter-wave plate, refractive index of a ridge portion of the ridge and trough periodic structure for the wavelength ?min and a light transmittance have predetermined values. The ridge and trough periodic structure satisfies the predetermined condition relating to the structural height and the structural width of the ridge portion.

Abstract: A method to store information in a holographic data storage medium, wherein the method supplies a holographic data storage medium comprising an encoded focusing hologram and one or more encoded data holograms. The method disposes the holographic data storage medium in a holographic data storage system, and disposes a rotatable imaging lens at an (i)th orientation. The method illuminates the encoded focusing hologram to generate an (i)th reconstructed focusing image, projects that (i)th reconstructed focusing image through the rotatable imaging lens, and onto at optical detector array. The method then calculates an (i)th measured focusing metric, and determines if the (i)th measured focusing metric is greater than or equal to the threshold focusing metric. If the (i)th measured focusing metric is greater than or equal to the threshold focusing metric, then the method decodes the one or more encoded data holograms.

Abstract: An optical pickup device, which reduces the size of an optical spot formed on an optical disk, and prevents the degradation of a tracking error signal due to coherent light from a layer adjacent a target recording/reproducing layer of the optical disk. The optical pickup device includes a light source emitting light at a designated wavelength; an object lens concentrating the light incident from the light source thereupon and forming an optical spot on an optical disk having multiple recording layers; and an optical detector receiving the light reflected by the optical disk and detecting a data signal and an error signal, wherein at least one diffraction pattern region partially diffracting or intercepting the light, emitted from the light source and being incident upon the object lens, and the light, reflected by optical disk and being incident upon the object lens, is formed on the object lens.

Abstract: According to one aspect, an optical recording and/or reproducing device for reading and/or writing an optical disc includes a base, optical pickup head, and a moving mechanism for slidably moving the optical pickup head. The moving mechanism includes a worm gear, a motor for rotating the worm gear, and a rack disposed between the worm gear and the optical pickup head for transferring motion from the worm gear to the optical pickup head. The rack includes a fastening portion for fixing the rack to the optical pickup head, an engaging portion for engaging with the worm gear, a restricting portion connected to the engaging portion for preventing the engaging portion from running out of the worm gear, and a connecting portion for connecting the fastening portion with the restricting portion.

Abstract: The present invention provides an optical pickup in which the transmission diffraction efficiency of plural recording and/or reproducing light beams of different wavelengths, radiated from plural light sources, may be prevented from being lowered, and in which the transmission diffraction efficiency and the angle of diffraction are both optimized.

Abstract: An optical pickup device has a semiconductor laser emitting light which is in turn branched via a diffraction grating into at least three beams of light including a main beam and two sub beams which are in turn condensed via an objective lens on an optical disk at a guide groove and reflected by the optical disk to provide three reflections of light which are in turn received by detectors, each divided into two regions, respectively, to generate a tracking error signal. The diffraction grating is divided into three regions including a first region, a second region and a third region located intermediate therebetween, each having a periodical structure out of phase, the periodical structure having grating grooves in a direction determined depending on the phase of the second region to incline relative to a direction perpendicular to the guide groove of the optical disk.

Abstract: An optical pickup for performing recording and/or playback of information by selectively irradiating the corresponding wavelength optical beam to first through third optical discs having a protection layer with different thickness, includes emission units for emitting first-wavelength through third-wavelength optical beams corresponding to the respective optical discs respectively, a condensing optical device for condensing each wavelength optical beam on an optical disc signal recording face, a divergence angle transformation device, which can be moved in the optical axis direction, for transforming the divergence angle of each wavelength optical beam according to the moved position in the optical axis direction so as to obtain a predetermined divergence angle, and a detector having a common light receiving unit for receiving each wavelength optical beam separated by an optical path separating unit and returned, with the condensing optical device condensing each wavelength optical beam on the corresponding o

Abstract: A chucking mechanism according to the present invention includes a claw member which retains a discoid disk and is arranged between a plurality of claw portions which put a radial force outwardly to a central opening portion of the disk and a plurality of claw portions, a receiving portion and a sliding portion.