Abstract: A method of discriminating an optical information storage medium. The method includes generating a signal obtained by summing the amount of light reflected by the optical information storage medium and received by a quadrant photodetector by moving an objective lens up and down at a predetermined speed while the optical information storage medium is loaded, outputting a first signal generated by comparing the sum signal with a first slice level, outputting a second signal generated by passing the sum signal through a band pass filter, outputting a third signal generated by comparing the second signal with a second slice level, outputting a fourth signal generated by performing an operation with respect to the first signal and the third signal, and determining the number of data layers of the optical information storage medium based on the fourth signal.

Abstract: A method of improving a defect countermeasure of an apparatus for reproducing an optical information storage medium. The method includes generating a defect detection signal corresponding to a defect duration from an RF signal input from an optical pickup, outputting a servo hold signal by performing an AND operation of the defect detection signal and a predetermined pulse width modulation signal, and if reproduction fails in a servo hold on state, switching the servo hold on state to a servo hold off state, outputting the servo hold signal again by reflecting a time delay on a pulse width of the servo hold signal when entering into the defect duration again, and adding track and focus offsets to a held servo value of the time delayed servo hold on duration. Accordingly, a countermeasure of a case where normal data reading fails due to a defect can be improved.

Abstract: A method of and apparatus for recording data on an optical recording medium form a mark or a space by using a recording waveform having an erase pattern containing a multi-pulse. The method and the apparatus prevent distortion of the mark or the space and improve a mark shape such that a recording/reproducing characteristic of the optical recording medium is improved.

Abstract: A method and apparatus to record data on an optical recording medium include generating a recording waveform having an erase pattern comprising a predetermined pulse having a high level which is higher than an erase power level and having a low level which is lower than the erase power level.

Abstract: A method and apparatus to record data on an optical recording medium include generating a recording waveform having an erase pattern comprising a predetermined pulse having a high level which is higher than an erase power level and having a low level which is lower than the erase power level.

Abstract: A focus pull-in method to perform an accurate focus pull-in operation in an optical disc drive using a holographic optical element (HOE) in consideration of a pseudo s-curve and an optical disc drive capable of performing the focus pull-in method, the method comprising checking whether a pseudo s-curve is contained in a focus error signal that is generated when an object lens of the optical disc drive is moved upwards or downwards, and, if the pseudo s-curve is contained in the focus error signal, controlling a focus pull-in operation for a disc loaded into the optical disc drive according to detection conditions for the pseudo s-curve. Accordingly, it is possible to accurately focus the data layer even during the driving of the disc that uses a wavelength that results in a low diffractive efficiency of the HOE.

Abstract: An apparatus and method for controlling a focus jump between recoding layers in a high-density multi-layer disk. The apparatus includes: an optical pickup including an objective lens focusing light on the disk, an aberration correcting unit, and a photodetector detecting light reflected from the disk; a signal processing unit generating a focus error signal from a signal output by the photodetector; a focus hold unit holding a focus servo of the optical pickup; a focus servo control unit controlling the focus servo of the optical pickup using the focus error signal; and a driving unit driving the optical pickup using a signal output by the focus servo control unit.

Abstract: A method of recording data on an optical recording medium includes forming a mark or a space using a recording waveform which includes a DC record pattern, and an erase pattern that includes a multi pulse. According to the method and an apparatus using the method, the distortion of a mark can be prevented and the shape of a mark can be improved, thereby increasing recording/reproducing characteristics.

Abstract: A method of processing a defect detection signal in a recording and/or reproducing apparatus that records and/or reproduces an optical information storage medium the method including generating a defect detection signal comprising a servo hold pulse from a radio frequency (RF) signal output from an optical pickup unit; and generating an OR signal by performing an OR operation on the defect detection signal and a first pulse signal having a first pulse width. The method further includes generating an AND signal by performing an AND operation on the OR signal and a second pulse signal having a second pulse width.

Abstract: A method and apparatus to record data on an optical recording medium include generating a recording waveform having an erase pattern comprising a predetermined pulse having a high level which is higher than an erase power level and having a low level which is lower than the erase power level.

Abstract: An apparatus and method for generating a tracking error signal (TES). A low level TES is prevented from being generated due to noise in an optical disk drive for reproducing a high-density multi-layered optical disk. The apparatus includes: an N-split optical reception element to receive light reflected by a disk loaded in the optical disk drive, a phase difference signal detection module to detect a plurality of phase difference signals using signals output from the N-split optical reception element, a pulse width modulation module to modulate pulse widths of the plurality of phase difference signals so that the pulse widths of the plurality of phase difference signals are magnified, and a difference detector to detect a difference between the plurality of phase difference signals whose pulse widths are modulated and outputting the detected difference as the TES. N may be a positive integer.

Abstract: A method of and apparatus for recording data on an optical recording medium form a mark or a space by using a recording waveform having an erase pattern containing a multi-pulse. The method and the apparatus prevent distortion of the mark or the space and improve a mark shape such that a recording/reproducing characteristic of the optical recording medium is improved.

Abstract: A method of and apparatus for recording data on an optical recording medium form a mark or a space by using a recording waveform having an erase pattern containing a multi-pulse. The method and the apparatus prevent distortion of the mark or the space and improve a mark shape such that a recording/reproducing characteristic of the optical recording medium is improved.

Abstract: A method of and apparatus for recording data on an optical recording medium form a mark or a space by using a recording waveform having an erase pattern containing a multi-pulse. The method and the apparatus prevent distortion of the mark or the space and improve a mark shape such that a recording/reproducing characteristic of the optical recording medium is improved.

Abstract: A recording method, a recording apparatus, and an optical recording medium that can improve quality of a signal reproduced from a high multi-speed recording medium. The recording method includes generating a box type recording pattern including a first pulse, which has a duration determined according to a length of a recording mark and which has a first power level, and a second pulse which has a second power level different from that of the first power level, and recording data according to the box type recording pattern.

Abstract: A method of and apparatus for recording data on an optical recording medium form a mark or a space by using a recording waveform having an erase pattern containing a multi-pulse. The method and the apparatus prevent distortion of the mark or the space and improve a mark shape such that a recording/reproducing characteristic of the optical recording medium is improved.

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: A method of determining an optimum write power of a recordable optical disk to control an optimum power of the recordable optical disk, and an optical disk driving apparatus using the same, the method including: performing a test, in which a test pattern is recorded on the optical disk and a write power by which a recording state of the test pattern is optimum is determined, a plurality of times by differently setting a start power each time; and determining optimum write power of the optical disk using optimum write power values obtained as a result of the tests.

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.

Abstract: An optical recording/reproducing apparatus and an OPC-performing method are provided for restudying drive characteristics of an optical source after performing OPC test recording and OPC measurement to ensure accurate optimum power control (OPC) for recording data on an optical disc, particularly, when the drive characteristics vary according to temperature changes of the optical source. The OPC-performing method comprises performing OPC recording as test recording for OPC and OPC measurement as measurement of an OPC recording state; performing a power analysis of drive characteristics of an optical source, and obtaining optical source drive characteristics after the OPC recording and the OPC measurement; and performing OPC calculation for determination of an optimum optical source drive level as an optical source drive level for enabling optimum beams of optimum recording power to be emitted from the optical source, based on the OPC recording state and the optical source drive characteristics obtained.