Abstract: An optical pickup includes an aberration correction element to correct chromatic aberration caused by variation of power from a light source when changing between operating modes in a recording medium. The aberration correction includes a first retardation member, which includes a stepped convex pattern with a plurality of steps at one side, and a second retardation member combined with the first retardation member. The second retardation member includes a stepped concave pattern with a plurality of steps at one side facing the first retardation member, the stepped concave pattern corresponding to the stepped convex pattern. The first and the second retardation members include different refractive indices for a light beam, which allows the first and the second retardation members to selectively create a phase difference of an incident light beam according to a polarization of the incident light beam.

Abstract: A compatible optical pickup including an optical unit and a focusing unit. The optical unit emits a short wavelength light for high-density recording media and a long wavelength light for low-density recording media, directs the short and long wavelength light to a recording medium, receives lights reflected by the recording medium, and detects an information reproduction signal and/or an error signal from the received lights. The focusing unit focuses light received from the optical unit to form a light spot on a recording surface of the recording medium, diffracts the short wavelength light into a zero order light and the long wavelength light into a second order light to be used as effective light for recording and/or reproduction. Thus, a high-density recording medium and a low-density recording medium having different thicknesses can be compatibly used.

Abstract: An optical head includes a substrate, a laser diode, a photodetector, an objective lens, a prism, and an optical element. The laser diode is installed on the substrate and emits light. The photodetector is installed on the substrate and receives the light. The objective lens is installed on a first side of the substrate and focuses the light emitted from the laser diode onto a recording surface of a disc. The prism is installed on a second side of the substrate, transmits the light emitted from the laser diode toward the objective lens, and transmits the light reflected from the recording surface toward the photodetector. The optical element adjusts an optical path formed between the substrate and the prism.

Abstract: An optical pickup apparatus for compensating for the deviation in the thickness of the optical disk and method therefor.

Abstract: A method of detecting a reproduction signal from an optical disc. A light beam reflected from a recording surface of an optical disc is divided into a central light beam portion and outer light beam portions in a direction corresponding to a radial direction of the optical disc. The central light beam portion and outer light beam portions are detected and a first detection signal from the central light beam portion and a second detection signal from at least one of the outer light beam portions are output. The amplitude of at least one of the first and second detection signals is adjusted and the reproduction signal is detected by subtraction between the first detection and second detection signals so that where reproduction is carried out on an optical disc having a varying track width the reproduction signal is improved.

Abstract: A disk clamping apparatus for a disk player includes a turntable for receiving a disk, a disk clamper which clamps the disk placed on the turntable, and first and second magnetic bodies which are mounted in the corresponding turntable and the disk clamper and provide a clamping force to the disk by acting a reciprocal magnetic force on the turntable and the disk clamper. The first and second magnetic bodies are opposite to each other and partially overlap each other. In the disk clamping apparatus having the above structure, the variation in a clamping force caused by the variation in thickness of disks, received by the disk clamping apparatus, is very small. Accordingly, clamping and de-clamping of the disks having different thickness can be smoothly performed.

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: A device for and method of reducing intersymbol interference (ISI) and/or crosstalk is disclosed. The ISI and crosstalk reducing device includes an optical detector which divides an optical signal reflected from an optical disk into central and peripheral parts in the tangential direction of the optical disk, and a correcting unit for controlling the gain value of a peripheral detection signal detected by the optical detector and adding the gain-controlled detection signal and a central detection signal to each other to provide an ISI corrected signal. Instead of using the existing waveform equalizer, the device uses a multiple-divided detection signal output from the optical detector to thereby obtain a jitter value of the same level as that obtained when the waveform equalizer is used. Further, in HD-DVD system requiring high density recording, it is possible to reduce crosstalk and ISI at the same time even when the high density recording causes crosstalk or interference between neighboring tracks.

Abstract: An optical recording medium having groove tracks and land tracks, first wobbles formed along both sidewalls of each of the groove tracks, second wobbles formed along both sidewalls of each of the land tracks and which are independent of the formation of the first wobble. A middle portion is formed at a predetermined position on each of the sidewalls between adjacent pairs of the land and groove tracks. This optical recording medium can significantly reduce the non-recordable area as compared to conventional optical recording media, resulting in a great improvement in recording density.

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 pickup apparatus for compensating for the deviation in the thickness of the optical disk and method therefor.

Abstract: An optical pickup apparatus including a swing arm pivotably installed in a tracking direction with respect to a disc, and an optical pickup unit supported by the swing arm and driven in a focusing direction, wherein the optical pickup unit includes a laser diode, an objective lens to focus light emitted from the laser diode on a recording surface of the disc, and a heat sink plate to dissipate heat generated from the laser diode, wherein the heat sink plate is provided close to the disc so as to be directly exposed to wind generated during rotation of the disc.

Abstract: An optical pickup apparatus having compatibility with a recodable compact disk (CD-R) and a digital video disk (DVD), which uses a wavelength of one of a first light beam and a second light beam according to the recording medium to be used. In the optical pickup apparatus, laser light sources emit a first light beam having a relatively shorter wavelength for the. DVD and a second light beam having a longer wavelength for the CD-R, respectively. An objective lens has a predetermined focal length in accordance with the position of an information recording surface in the DVD. An optical path control unit controls the path of light beams so that the light beam emitted from one of the laser light sources is directed to the objective lens and the light output from the objective lens is directed to the optical detection unit.

Abstract: An optical head includes a substrate, a laser diode, a photodetector, an objective lens, a prism, and an optical element. The laser diode is installed on the substrate and emits light. The photodetector is installed on the substrate and receives the light. The objective lens is installed on a first side of the substrate and focuses the light emitted from the laser diode onto a recording surface of a disc. The prism is installed on a second side of the substrate, transmits the light emitted from the laser diode toward the objective lens, and transmits the light reflected from the recording surface toward the photodetector. The optical element adjusts an optical path formed between the substrate and the prism.

Abstract: A disk cartridge includes a case which contains a disk, and a shutter which opens/closes at least one opening formed in the case. The shutter is configured to be foldable around upper and lower surfaces of the case, and slides on the upper and lower surfaces of the case to open/close the opening. Since the shutter opens/closes the opening while being folded around the upper and lower surfaces of the case, a movable distance of the shutter for opening/closing the opening can be fully accommodated even though the size of the disk cartridge is reduced. In addition, applying the configuration of the shutter to a double-sided disk cartridge prevents an inflow of dust from entering into the double-sided disk cartridge since the shutter closes an opening, which is not in use, during a recording/reproducing operation.

Abstract: An objective lens device and an optical pickup employing the objective lens device. The objective lens device is formed of three lenses including a lens having a negative power and formed of material having an Abbe number which is 45 or less in line d. At least one surface of surfaces of the three lenses is formed to be aspherical. Thus, in the objective lens device, a high numerical aperture of 0.70 or more is realized and chromatic aberration is corrected with respect to blue light enabling improved recording and/or reproduction using blue light.

Abstract: An optical pickup capable of focusing a main light spot and an auxiliary light spot including optical aberration when an optical disk is not tilted, and analyzing the main light spot and the auxiliary light spot with a photodetector, thereby correcting aberration.

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 optical pickup actuator for use with a recording medium includes a swing arm pivoting in a tracking direction with respect to the recording medium, a first driving unit pivoting the swing arm, an optical pickup facing the recording medium, an elastic member having one end fixed to the swing arm and a free end portion elastically deformable in a focus direction with respect to the recording medium, wherein the optical pickup is coupled to the free end portion of the elastic member, and a second driving unit deforming and driving the elastic member.

Abstract: An actuator for an optical pickup includes a base, a holder fixed to the base, a moving portion on which an objective lens for focusing incident light onto a disc and a liquid crystal panel for correcting spherical aberration are mounted, a magnetic driving portion which drives the moving portion in a radial direction and in a focusing direction relative to the disc, and a connection section which includes a first connection part which serves as an electrical connection path of a signal used to drive the magnetic driving portion and has at least four wires, and a second connection part electrically independent of the first connection part, which serves as an electrical connection path of a signal used to drive the liquid crystal panel, and has wires, and which supports the moving portion to be movable with respect to the holder.