Abstract: A method of detecting a servo error, an apparatus therefor, a disk which maintains quantity of a servo error signal, a method of controlling a servo of an apparatus for recording data on and reproducing data from a disk, a method of detecting the tracking error, and a method of detecting tilt error of the apparatus.

Abstract: An error signal detecting apparatus for an optical recording/reproducing apparatus, the error signal detecting apparatus including a photodetector to receive light reflected and diffracted by a recording medium, and a signal processor to detect an error signal by calculating a detection signal of the photodetector. The photodetector includes a plurality of light receiving areas to independently receive light of a light area in which the profile of the light changes to the opposite profile according to the tangential tilt of the recording medium. The signal processor detects a tangential tilt error signal from detection signals of the light receiving areas. Thus, a signal output from the error signal detecting apparatus does not change when a shift is generated in the objective lens or the distance between the objective lens and the disc is deviated from the on-focus position.

Abstract: A method of detecting a servo error, an apparatus therefor, a disk which maintains quantity of a servo error signal, a method of controlling a servo of an apparatus for recording data on and reproducing data from a disk, a method of detecting the tracking error, and a method of detecting tilt error of the apparatus.

Abstract: A tracking error signal detecting apparatus with improvement in offset due to gain characteristics and/or a difference in the depth between pits by providing an improved sectioning structure of an eight-sectional photodetector having inner and outer sectional plates, the radial widths of which vary along the tangential direction from the center of the photodetector, and a reproduction signal detecting apparatus with reduced crosstalk noise. The tracking error signal detecting apparatus can allow accurate tracking control in a high-density recording medium having relatively narrow tracks. Also, the reproduction signal detecting apparatus can correct signal distortion due to a difference between phase characteristics of detection signals of inner and outer sectional plates of a photodetector even during reproduction of an information signal from a high-density recording medium having relatively narrow tracks, thereby detecting an improved reproduction signal with greatly reduced crosstalk.

Abstract: A recording and/or reproducing apparatus and a method of controlling the same. The method of controlling the apparatus for recording information in or reproducing information from a disc having a wobbled track, the method includes detecting a wobble signal recorded in the wobbled track, and removing an error component occurring during the recording or the reproducing, based on the detected wobble signal. Accordingly, errors arising from a variety of factors can be accurately compensated for during a recording or reproducing operation.

Abstract: A method of detecting a servo error, an apparatus therefor, a disk which maintains quantity of a servo error signal, a method of controlling a servo of an apparatus for recording data on and reproducing data from a disk, a method of detecting the tracking error, and a method of detecting tilt error of the apparatus.

Abstract: A method of detecting a servo error, an apparatus therefor, a disk which maintains quantity of a servo error signal, a method of controlling a servo of an apparatus for recording data on and reproducing data from a disk, a method of detecting the tracking error, and a method of detecting tilt error of the apparatus.

Abstract: An error signal detection apparatus for an optical recording/reproducing system which detects a tilt error signal and/or tracking error signal, based on the phase characteristics of light reflected and diffracted from a recording medium, and a method therefor. The error signal detection apparatus includes multiple photodetectors and a circuit unit for detecting an error signal by processing detection signals generated by each photodetector The the photodetectors are arranged in a matrix wherein a row or column of the matrix is parallel to a direction corresponding to a direction of an information stream on the recording medium. A circuit unit compares the phases of the detection signals of the inner and/or outer light receiving portions arranged in the same row or of detection signals from diagonal positions on the matrix to output at least one of a tilt error signal and a tracking error signal based on the phase comparison.

Abstract: An optical pickup apparatus includes a first light source to emit a first light beam having a predetermined wavelength, a first optical path changer to change a proceeding path of the first light beam, an objective lens to focus the first light beam on a recording medium, a diffraction member to divide the first light beam reflected by the recording medium into five light regions, the diffraction member having a first diffraction region having a wide width in a direction corresponding to a tangential direction of the recording medium and second through fifth diffraction regions sequentially arranged around the outside of the first diffraction region in a direction corresponding to a radial direction of the recording medium, and a first photodetector having first through fifth light receiving portions to receive the first light beam reflected by the recording medium.

Abstract: A method of detecting a servo error, an apparatus therefor, a disk which maintains quantity of a servo error signal, a method of controlling a servo of an apparatus for recording data on and reproducing data from a disk, a method of detecting the tracking error, and a method of detecting tilt error of the apparatus.

Abstract: A differential phase detection device receives first through fourth detection signals from a photodetector and detects a differential phase signal therefrom, the differential phase detection device includes a slicer slicing and digitizing each of the detection signals with respect to a reference level. A synthesizer synthesizes the digitized detection signals and generates therefrom synthesis signals. A phase difference detector compares phases of the synthesis signals and outputs a first phase difference signal and a second phase difference signal. A matrix circuit processes the first and second phase difference signals to output the differential phase signal.

Abstract: At least part of a light beam reflected from an optical disc is divided into first through fourth light areas in directions corresponding to the radial and tangential directions of the disc, and first through fourth detection signals are output from the light areas. The first through fourth light areas are ordered counterclockwise or clockwise. A phase difference is obtained between a first sum signal obtained by summing the first and third detection signals and a second sum signal obtained by summing the second and fourth detection signals and first and second phase difference signals are output based upon the phase difference. The phase difference signals are summed to generate an optical recording/reproducing system monitoring signal for system adjustment even for high density optical discs, the monitoring signal being proportional to the degrees of a radial tilt, tangential tilt, a defocus, or a detrack.

Abstract: An optical recording/reproducing apparatus for determining a direction in which an optical pick-up moves, and detecting a track cross signal. The track cross signal is useful as a basis of determining tracking pull-in after searching a track. In the present track cross signal detecting method, the track cross signal is obtained by binarizing the envelope of an RF signal RF0 obtained by subtracting some light receiving signals generated by some light receiving devices in the radial direction from other light receiving signals generated by other light receiving devices in the radial direction. The light receiving signals originate from a photodetector, divided into two or more sections in the radial direction. The track cross signal detecting method is especially useful for generating the track cross signal when the track pitch is smaller than the size of an optical spot, the signal being less affected by crosstalk caused by an adjacent track.

Abstract: An error signal detection apparatus for an optical recording/reproducing system including a light source emitting a light beam and an objective lens focusing the light beam to form a light spot on a recording medium, the apparatus including: a photodetecting unit dividing at least a part of the light beam passed through the objective lens after being reflected/diffracted from an information stream of the recording medium into light beam portions, and detecting the light beam portions; and a signal processor detecting phase differences between detection signals from the light beam portions to detect a tangential error signal, a defocus error signal, and/or a radial tilt error signal.

Abstract: An apparatus for and a method of detecting a defocus error signal. First, second and third light receiving regions of a photodetector are arranged in a radial direction of a recording medium to independently perform photoelectric conversion with respect to incident light which is reflected/diffracted by the recording medium. A subtractor subtracts a sum signal of detection signals from the first and third light receiving regions and a detection signal of the second light receiving region to output a defocus error signal, to detect defocus and/or a change in thickness of the recording medium. The defocus error signal and a push-pull tracking error signal are compared in a state in which a predetermined amount of defocus is applied to a light spot to detect a seek direction of the recording medium having a land/groove structure.

Abstract: An apparatus for use in an optical disc includes an optical disc and an optical branching unit irradiating a main light beam and a sub-light beam, wherein the sub-light beam includes a optical aberration in a direction on a track of the optical disc. The apparatus further includes a photodetector including a plurality of portions receiving and processing the main light beam and a plurality of portions receiving and processing the sub-light beam. A track error signal detector detects a track error signal from the portions receiving the main light beam. A track cross signal detector detects a track cross signal from the portions receiving the main light beam and from the portions receiving the sub-light beam. A signal processor further compares the track error signal with the track cross signal to detect the seek direction of a light spot formed on the optical disc.

Abstract: An error signal detection method and apparatus for an optical recording/reproducing system.

Abstract: An apparatus to generate a seek direction detecting signal for an optical pickup to determine a position of a center of an optical spot focused on an optical disk relative to a center of a track, which focuses a main beam on a first optical detector and a sub-beam having a predetermined aberration in a radial direction on a second optical detector using a light dividing unit. The second optical detector has an inner and an outer pair of light receiving portions arranged along the radial direction, the inner pair being between the outer pair. A signal processing portion includes a first signal processing portion to detect a track error signal from signals output from the first optical detector, and a second signal processing portion to generate the seek direction detecting signal from signals detected by the second optical detector and the track error signal.

Abstract: An error signal detecting apparatus for an optical recording/reproducing apparatus, the error signal detecting apparatus including a photodetector to receive light reflected and diffracted by a recording medium, and a signal processor to detect an error signal by calculating a detection signal of the photodetector. The photodetector includes a plurality of light receiving areas to independently receive light of a light area in which the profile of the light changes to the opposite profile according to the tangential tilt of the recording medium. The signal processor detects a tangential tilt error signal from detection signals of the light receiving areas. Thus, a signal output from the error signal detecting apparatus does not change when a shift is generated in the objective lens or the distance between the objective lens and the disc is deviated from the on-focus position.

Abstract: An apparatus for generating a seek direction detecting signal for an optical pickup determining the relative position of the center of an optical spot focused on an optical disk with respect to the center of a disk track, is disclosed. The apparatus focuses a main beam and a sub-beam having a predetermined aberration in the tangential direction on a track of the optical disk by a light dividing unit. The main beam is focused on a first optical detector, and the sub-beam is focused on a second optical detector neighboring the first optical detector. The second optical detector is divided into three or four portions in a direction corresponding to the radial direction of the optical disk, is divided into two portions in a direction corresponding to the tangential direction of the optical disk, and therefore has six or eight separate areas. The portions of the second optical detector receive the portions of the sub-beam and convert the received optical signals into independent electrical signals.