Abstract: An optical information storage medium includes a lead-in area, a user data area, and a lead-out area. Data is recorded as a pit wobble in all, or a portion of, the lead-in area and data is recorded as pits in the remaining area of the optical information storage medium. A method records data on, and/or reproduces data from, the optical information storage medium.

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 having a plurality of objective lenses. At least one of the plurality of objective lenses is configured so that a type of wavefront error mainly generated by a tilt of the at least one of the plurality of objective lenses is the same as a type of a wavefront error mainly generated by an angle at which light is incident upon the at least one of the plurality of objective lenses.

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: A spherical aberration compensator for compensating for spherical aberration resulting from a thickness deviation of a recording medium. The spherical aberration compensator includes a central compensation which provides a phase distribution that is effective for compensating for spherical aberration resulting from the thickness deviation and a peripheral compensation portion which surrounds the central compensation portion and provides a phase distribution that is effective for reducing a worsening of the spherical aberration caused by axial displacement of an objective lens from the central compensation portion. The spherical aberration compensator effectively relieves an optical pickup having an objective lens of an NA of 0.7 or greater of worsening of the spherical aberration resulting from thickness deviation of 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. 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: An optical information storage medium includes a lead-in area, a lead-out area, and a user data area between the lead-in and lead-out areas and in which user data is recorded. Pits are formed in the lead-in area, the user data area, and the lead-out area, and a track pitch in all or a portion of the lead-in area is different from a track pitch in the remaining area of the optical information storage medium.

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: An objective lens includes an aspherical lens facing a disk and having a predetermined first focal distance and a predetermined numerical aperture, and a holographic lens installed adjacent to the aspherical lens and having a second focal distance longer than that of the first focal distance and having a diffraction lattice to compensate for the chromatism due to a change in wavelength of laser light having a wavelength of 670 nm or less. Thus, during the shift between recoding and reproduction of a DVD or an HD-DVD, the change in wavelength due to the change in power of the laser light and chromatism according to the change can be effectively corrected. Also, since the objective lens is formed of one aspherical lens and one holographic lens, the material for each of the lenses can be easily selected and also the structure of the optical pickup using the objective lens according to the present invention can be simplified.

Abstract: A disc cartridge includes a case accommodating a disc and having an aperture hole formed on a first surface of the case so that a recording/reproducing apparatus access a recording surface of the disc, and an open hole formed on a second surface to be open to an outside of the case, a shutter opening/shutting the aperture hole and installed in the case, a disc holder installed at a side defining the open hole to move up and down and covering a gap between an outer circumference of the disc and an inner surface of the side defining the open hole when the disc holder descends, and a shutter driving mechanism moving the shutter so that the aperture hole is open/shut. Thus, a passage through which dust is introduced toward an information area of the disc, and a gap formed at an outer circumference are blocked by the disc holder so that a possibility of contamination by dust can be reduced.

Abstract: A land/groove discriminating method and an optical recording and/or reproducing apparatus employing the method are provided. The land/groove discriminating method emits a light beam onto an optical disc having lands and grooves through an optical element capable of causing and varying an effect of thickness variation of the optical disc, detects a light beam reflected/diffracted from the optical disc by dividing the reflected/diffracted light beam into inner and outer light beam portions, and discriminates between a land and a groove of the optical disc by detecting variation in a difference signal between detection signals from the inner and outer light beam portions while varying the degree of the effect of thickness variation of the optical disc by driving the optical element.

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 pickup apparatus which reduces cross talk by adjacent tracks. The optical pickup apparatus divides light reflected from an optical recording medium as a spot into center and side portions defined with respect to the radial direction of the recording medium and provides electrical signals corresponding to the reflected light in divided form. An operation unit multiplies signals corresponding to the side portions by an operation constant, adds the multiplication results and the detected signal of the center portion, and outputs an information signal of a main track with reduced cross talk by adjacent tracks in real time. The optical efficiency is sufficient that recording of an information signal can be performed with the optical pickup.

Abstract: A recording/reproducing apparatus including an optical pickup compatible with a plurality of optical recording media each using light of a different wavelength. The optical pickup includes at least one light source, an objective lens having a function of focusing light emitted from the light source into the optimal light spot on an information recording surface of one of the plurality of the optical recording media, and a light detector to detect light transmitted through the objective lens after being reflected from the information recording surface of the optical recording medium on which the light spot is formed. The objective lens has an inner area, an annular lens area and an outer area such that the annular lens area divides the inner area from the outer area and has a ring shape centered at a vertex.

Abstract: A disk cartridge includes a lower case having an opening formed thereon, an upper case installed at the lower case to be capable of being open and shut while pivoting, to accommodate a disk therebetween, a shutter installed at the lower case to be capable of sliding and opening and shutting the opening hole, a close covering member having an inclined surface installed at the shutter to be capable of sliding, closely contacting a non-information area disposed at an inner circumference of the disk when the shutter is closed, and being separated from the non-information area disposed at the inner circumference of the disk when the shutter is open. Thus, when the shutter is closed, introduction of dust is prevented so that the possibility of the information area of the disk being contaminated is lowered. Also, since the disk is fixed between the upper and lower cases, while the disk is carried, noise and damage can be reduced.

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 disk cartridge includes a case accommodating a disk, a cover installed at the case to be capable of being open and shut and having a hole formed thereon to be open to an outside of the cover, a shutter installed under the disk in the case to be capable of moving to open and shut an opening formed on the case, and a clamping member installed at the cover to seal the hole to clamp the disk. Thus, since the clamping member blocks the hole of the cover connected to the outside of the cover, possibility of intrusion of dust into the disk cartridge is reduced. Also, since there is no need to install the clamping member at the disk drive, the disk drive can be made simplified and slim.

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.