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 actuator of an optical disk system and an apparatus producing a signal for driving the actuator, the actuator including a light source, with which information is recorded on or reproduced from an optical disk surface. In the actuator, an inner focusing coil and an outer focusing coil are installed near an inner boundary and an outer boundary, respectively, of the optical disk surface. A first signal wire is connected to a first port of the inner focusing coil and transmits an inner coil signal. A second signal wire is connected to a first port of the outer focusing coil and transmits an outer coil signal. A common signal wire is connected to a second port of the inner focusing coil and a second port of the outer focusing coil and transmits a common reference signal. Thus, a simple, inexpensive 8-wire actuator can be obtained.

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: 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: 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 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. A wobble signal obtained by phase modulating address information indicating the physical identification information and a wobble signal having only a simple carrier are recorded in each groove track by way of time division multiplexing. Groove tracks are divided into odd groove tracks and even groove tracks, and a wobble carrier and wobble address information are alternately recorded in each groove track and between odd and even groove tracks such that the wobble address information is not recorded in a section of an even groove track corresponding to a section of an odd groove track in which the wobble address information is recorded. Therefore, interference between wobble signals of adjacent tracks can be removed, and a method and a circuit for detecting a wobble address can be simplified.

Abstract: An apparatus for and a method of reproducing information from an optical information storage medium (OISM) in which inherent information and control data are recorded according to a bi-phase modulation method and other data are recorded according to a general modulation method. Sum signals of signals reflected from the OISM are determined. A ROM-PIC demodulator demodulates optical information storage medium-related information (OISMRI) from the sum signal. A data demodulator demodulates reproduction-related user data from the sum signal, a wobble PIC demodulator demodulates recordable OISMRI recorded as pit wobbles from a differential signal of the reflected signals, and a wobble PID demodulator demodulates physical identification data that is recorded as pit wobbles from the differential signal. A determination is made whether the OISM is a read-only OISM or a recordable OISM based on whether the optical information storage medium comprises a plurality of different modulation codes.

Abstract: An adaptive focusing apparatus and method thereof of an optical disc drive having a focus servo controller moves a pickup head to an optimal focus point. A disc driver rotates an optical disc and includes a reflected signal detector detecting a signal reflected from the optical disc by the pickup head and a signal processor preventing spikes between a surface of the optical disc and the pickup head in response to the reflected signal and generating a focus drive signal for the focus servo controller using an adaptive focus search algorithm. The algorithm includes a static part and a dynamic part to reduce a focus search time. Accordingly, damage to the optical disc due to spikes between the surface of the optical disc and the pickup head can be prevented and a focus search time can be reduced.

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 optical information storage medium and a method of recording and/or reproducing information on and/or from the optical information storage medium includes a lead-in area, a user data area, and a lead-out area in which data is recorded. The data that is not modified on storage media complying with the same physical format is recorded in the entire lead-in area or a portion of the lead-in area. A data recording modulation method used in the entire lead-in area or the portion of the lead-in area is different from a data recording modulation method used in a remaining area of the optical information storage medium.

Abstract: An optical recording medium and a recording/reproducing method therefor to stably and accurately address a basic recording and/or reproducing unit (a sector or a frame) when a track pitch is decreased for recording of a large capacity of data. The general information (e.g., a variable frequency oscillator, a sector number, a sector type, and error detection information) of a corresponding sector is read from a header, which has physical pits between adjacent land and/or groove tracks, before recording or reproducing. The arrangement of the header is in the form of physical pits, with a sector structure where 2-kilobyte minimum recording units are included in a user area within a basic recording unit of 4 kilobytes, which thereby reduces overhead and facilitates the generation of a servo control signal.

Abstract: A data recording, reproducing, detecting and/or evaluating apparatus includes a modulator which modulates input information data by a predetermined modulation method, according to a first clock signal having a basic clock period (T) for recording/reproducing data, and a bit expander which expands bits for a modulated bitstream according to a second clock signal that are a predetermined multiple of the first clock signal. By forming pits with an nT length and not forming pits with an (n±1)T length on the information storage medium, stable reproduction of data is enabled.

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 and apparatus preventing a disc from being scratched by an objective lens. A focus pull-in operation is performed. If a level of a pull-in signal remains lower than a predetermined critical level for a predetermined critical period of time or more, the objective lens is controlled so as to move away from the disc.

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. The apparatus for recording data on and reproducing data from the disk in which a recording area is divided into sectors, each sector has a header for indicating an address, each header has a first header and a second header which are recorded to deviate from the center of the track in opposite directions, and the first header and the second header have address areas in which the addresses of sectors are recorded and synchronous signal areas in which synchronous signals for detecting the address signals recorded in the address area are recorded.

Abstract: A method of, and an apparatus for detecting a radial tilt of a disc. Phases of summed signals obtained from signals that external light-receiving units of an octant photo diode receive are compared to generate an external phase comparison signal Do. Phases of other summed signals obtained from other signals, that internal light-receiving units of the octant photo diode receive, are compared to generate the internal phase comparison signal Di. The radial tilt is detected based on the internal and external phase comparison signals Di and Do obtained when a laser beam crosses a track formed the disc. Thus, the radial tilt can be more precisely detected.

Abstract: A compatible optical pickup compatibly using a high density recording medium and at least one low density recording medium, includes an objective lens to form a light spot suitable for use on a recording surface of the high density recording medium by focusing a corresponding incident light beam with a high NA suitable for the high density recording medium and a light spot suitable for use on another recording surface of the low density recording medium by focusing another corresponding incident light beam, and an actuator provided to apply tilt to the objective lens. The light beam for the low density recording medium is incident on the objective lens as a divergent beam. When the objective lens is shifted in a radial direction, a tilt is applied to the objective lens corresponding to the shift.

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: A physical identification data (PID) addressing method using a wobble signal, a wobble address encoding circuit, method and circuit for detecting the wobble address and a recording medium therefor. When addressing physical identification information on a recording medium, which has land and groove tracks in which data can be recorded, using wobbles, a wobble signal obtained by phase modulating address information indicating the physical identification information and a wobble signal having only a carrier are repeatedly alternatively recorded on both walls of either of a groove track and a land track by way of time division multiplexing. Accordingly, land and groove addresses can be detected by the same method, and the land track can be easily discriminated from a groove track by making the sizes of the addresses different in the land and groove tracks.

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.