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: A physical identification data (PID) addressing method using a wobble signal, a wobble address encoding circuit, a method and circuit for detecting the wobble address and a recording medium therefor. Groove tracks are classified into odd groove tracks and even groove tracks. Address information indicating physical identification information is phase modulated using wobble signals having a predetermined phase difference between two adjacent groove tracks, and recorded in each groove track so that address information modulated using the wobble signals having the phase difference of 90° between adjacent two groove tracks can be a quadrature phase shift keying (QPSK) signal. Accordingly, a larger amount of data can be recorded on the recording medium, and since an interval in which a wobble signal disappears is not caused, recovery of a wobble clock signal can be advantageously performed.

Abstract: A method of determining a type of an optical disc loaded into a data recording and/or reproducing apparatus, which includes a plurality of laser diodes and records data onto and/or reproduces data from diverse types of optical discs, and the data recording and/or reproducing apparatus for implementing the method. The method includes selecting one laser diode from among the plurality of laser diodes, radiating light onto the loaded optical disc while approaching and/or withdrawing the selected laser diode to and from the loaded optical disc, counting a number of reflection signals generated from the light reflected from the loaded optical disc, and determining the type of the loaded optical disc based on the number of reflection signals.

Abstract: An apparatus for recording data on and reproducing data from the disk in which a recording area is divided into sectors, includes a reproducing signal generator for generating a reproducing signal including sum signals V1 and V2 of radial pairs, a sum signal RF_sum, and a push-pull signal RF_pp from an optical signal reflected from the disk, a header area detector for generating a header area signal including a header area from the reproducing signal, a first synchronous signal level detector for detecting a magnitude Ivfo1 of a first synchronous signal in the first header by being synchronized with the header area signal, a second synchronous signal level detector for detecting a magnitude Ivfo3 of a second synchronous signal in the second header by being synchronized with the header area signal, and a balance calculator for calculating the balance of the magnitude Ivfo1 and the magnitude Ivfo3.

Abstract: Provided are a semiconductor laser device and a method for manufacturing the same. The method comprises the steps of: sequentially laminating a first conductivity-type clad layer, an active layer, a second conductivity-type clad layer, and a second conductivity-type cap layer on a substrate; forming a metal film pattern on the second conductivity-type cap layer; forming a protective insulating film pattern on the metal film pattern; etching the second conductivity-type cap layer and the second conductivity-type clad layer using the protective insulating film pattern as an etching mask to form a ridge structure on the second conductivity-type clad layer; forming a current blocking layer over a whole surface of the laminate; exposing the metal film pattern to form a contact opening; and forming a top electrode layer on a surface of the metal film pattern exposed by the contact opening.

Abstract: An apparatus for and a method of producing a push-pull tracking error signal in an optical disc system having four light-receiving sections A, B, C, and D arranged in a radial direction of the optical disc. Pairs of signals PA, PB, PC and PD, corresponding to light receiving sections A, B, C and D, respectively are differentially combined to provide differential signals. One differential signal is filtered, amplified and differentially combined with another differential signal to output a tracking error signal. Accordingly, distortion of the tracking error signal during jumping to a desired track and distortion of the tracking error signal due to a defect of the optical disc are prevented.

Abstract: A disk area type detection method and apparatus, the disk area type detection method including detecting the difference between a side push-pull (SPP) 1 signal and an SPP2 signal; and determining whether an area is a storage medium related information area or a user data area on the disk, based on the detected difference. According to the method and apparatus, the user data area and the storage medium related information area of the disk can be easily distinguished, allowing phase locked loop (PLL) control to be performed appropriately.

Abstract: A method and circuit for providing a playback signal which is compensated for time delay. The circuit includes a time delay compensator for detecting a time difference between outputs of a photodetector and temporally matching part of the outputs of the photodetector and another part of the outputs of the photodetector, between which the time difference occurs, to compensate for time delay between different outputs of the photodetector, and an operational unit for summing the part of the outputs of the photodetector, which is compensated for the time delay, and the other part of the outputs of the photodetector to provide a playback signal. Accordingly, the circuit compensates for the time delay between the outputs of the photodetector, thereby increasing the degree of modulation of the data playback signal.

Abstract: A method of determining an optical disc type and a data recording and/or reproducing apparatus. The method of determining the type of an optical disc loaded in a data recording and/or reproducing apparatus includes reading optical disc type determination order stored in a memory included in the data recording and/or reproducing apparatus in order to determine a type of the optical disc from a plurality of optical disc types, and controlling a read/write unit in the data recording and/or reproducing apparatus according to the determination order to determine the type of the optical disc. According to the present invention, an optical disc using pattern of users, optical disc using frequency according to type, and a point of time in which an optical disc is used are considered to change an order for optical disc type determination to allow to rapidly determine the type of a loaded optical disc.

Abstract: A tray movement speed control method and apparatus. The method of controlling a tray movement speed includes: receiving tray movement speed setting information through a user interface; receiving the tray movement speed setting information from the user interface through a host interface; and setting a tray movement speed according to the received tray movement speed setting information. According to the method and apparatus, by allowing a user to adjust a loading speed set when a product is shipped, tastes and sensitivities of individual user groups may be satisfied and degradation of the recording and/or reproducing performance of a disc due to abnormal loading of a disc may be prevented.

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: 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 generating a seek direction detecting signal includes a light dividing unit dividing an incident light beam into at least two beams having a main beam and a sub-beam so that at least two beam spots including a main beam spot and at least one sub-beam spot having an optical aberration, can be focused in the track direction of an optical disk, the light dividing unit providing that the direction of the optical aberration of the sub-beam spot can be the tangential direction of the optical disk, an optical detector unit, a first signal processing portion processing a track error signal from signals output from the optical detector, a second signal processing portion processing a track cross signal from the signals output from the optical detector, and a generator generating the seek direction detecting signal from the phase difference between the track cross signal and the track error signal.

Abstract: A method and apparatus for detecting the direction of movement of a laser spot in an optical disc recording/reproducing apparatus having a photodetector divided into two or more sections, each of which is a light receiving device, aligned in a radial direction that includes detecting a phase difference between the light receiving signals corresponding to light receiving devices of the photodetector. A first phase difference signal is obtained that indicates the degree to which the phase of the light receiving signal corresponding to a first light receiving device farthest advanced in the radial direction leads the phase of the light receiving signal corresponding to a second light receiving device. A second phase difference signal is obtained that indicates the degree to which the phase of the light receiving signal corresponding to the second light receiving device leads the phase of the light receiving signal corresponding to the first light receiving device.

Abstract: An error signal detection method includes detecting light incident through an objective lens after having been reflected and diffracted from a recording medium, as eight light portions in a matrix including four inner light portions and four outer light portions, wherein the rows and columns of the matrix are parallel to the tangential and radial direction of the recording medium, respectively; calculating a first sum signal by summing a detection signal from at least one outer light portion located in a first diagonal direction, and a detection signal from an inner light portion located in a second diagonal direction; calculating second sum signal by summing a detection signal from an inner light portion located in the first diagonal direction, and a detection signal from an outer light portion located in the second diagonal direction; and comparing phases of the first and second sum signals to detect a tilt error signal.

Abstract: A method and apparatus for tracking error detection in an optical disk reproduction system. The tracking error detecting apparatus generates a tracking error signal as a difference signal of optical detection signals generated by more than two optical detectors positioned along a diagonal line from a track center and includes binarizers which binarize each output of the optical detectors, phase locked loops (PLLs) which generate respective clock signals synchronized with the outputs of each of the binarizers, a phase difference detector which detects a phase difference between the synchronized signals output from the PLLs, and low-pass filters which filter the output of the phase difference detector to output the result as the tracking error signal. The tracking error detecting apparatus generates a tracking error signal which is not dependent on the lengths of pits or marks recorded on an optical disk, enhancing the reliability of the tracking error signal.

Abstract: A physical identification data (PID) addressing method using a wobble signal, a wobble address encoding circuit, a method and circuit for detecting the wobble address and a recording medium therefor. Groove address information indicating physical identification information is phase modulated using a wobble clock signal and recorded in one of the two walls of a groove track, and land address information is phase modulated using a wobble clock signal obtained by shifting the phase of the former wobble clock signal and recorded in the other wall. That is, address information is phase modulated and recorded in each track using the wobbles having a phase difference of 90° between adjacent tracks so that a sum of wobble signals from the adjacent tracks can be a quadrature phase shift keying (QPSK) signal. Therefore, more data can be recorded in the recording medium, and since an interval in which a wobble signal disappears is not caused, recovery of a wobble clock signal can be advantageously performed.

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

Abstract: A method and apparatus for tracking error detection in an optical disk reproduction system. The tracking error detecting apparatus generates a tracking error signal as a difference signal of optical detection signals generated by more than two optical detectors positioned along a diagonal line from a track center and includes binarizers which binarize each output of the optical detectors, phase locked loops (PLLs) which generate respective clock signals synchronized with the outputs of each of the binarizers, a phase difference detector which detects a phase difference between the synchronized signals output from the PLLs, and low-pass filters which filter the output of the phase difference detector to output the result as the tracking error signal. The tracking error detecting apparatus generates a tracking error signal which is not dependent on the lengths of pits or marks recorded on an optical disk, enhancing the reliability of the tracking error signal.

Abstract: A method of and a circuit for providing a playback signal, which is compensated for time delay, from a photodetector having a plurality of outputs. A time difference between a first signal corresponding to a part of the outputs of the photodetector and a second signal corresponding to another part of the outputs of the photodetector is detected and one of the first and second signals is temporally shifted to compensate for a time delay between different outputs of the photodetector. The temporally shifted signal is summed with the other signal to provide a playback signal. Accordingly, the time delay between the outputs of the photodetector is compensated, thereby increasing the degree of modulation of the data playback signal. In addition, distortion or degradation of the signal is suppressed and occurrence of errors in the playback signal is minimized, thereby improving the reliability of the playback signal.