Abstract: A DVD-RAM disk reproduction apparatus for reducing an error during detection of ID data, which includes a first operational amplifier for obtaining a sum signal resulting from the addition of four picked-up signals picked up by divided-by-four photodiodes from a DVD-RAM disk having a header region and a recording region, second and third operational amplifiers for respectively obtaining two sum signals corresponding to the upper and lower regions of the header region resulting from the addition of the first and second picked-up signals and the third and fourth picked-up signals, respectively, a fourth operational amplifier for obtaining a difference signal between the two sum signals, a header region detector for detecting upper and lower header region signals corresponding to the upper header region and the lower header region based on the difference signal, and detecting a header region signal corresponding to a header region by logically summing the two detected signals, a first multiplexer for selecting o

Abstract: An optical pickup of an optical disk drive. The optical pickup includes a laser beam source for generating a laser beam; a pickup base having an objective lens for projecting the laser beam generated from the laser beam source to an information recording surface of an optical disk; a variation adjusting plate which is movably disposed on the pickup base to be moved in vertical and lateral directions, and has a rotational hole formed at a central portion thereof; and a rotation adjusting plate including a rotational section having a predetermined curvature which is inserted into the rotational hole of the variation adjusting plate, and with a laser beam source fixed therein, the rotation adjusting plate being rotated with respect to the variation adjusting plate. An optical system including a collimating lens and a reflective mirror is fixed to the pickup base.

Abstract: An optical pickup records information on a recordable and reproducible disk and reads information therefrom. The optical pickup includes a laser light source for emitting first laser light in case of a reproduction mode for reproducing information from the disk and emitting second laser light in case of a recording mode for recording information on the disk. A collimating lens collimates the laser light emitted from the laser light source. A chromatic aberration corrector includes prisms of respectively different material properties, for beam-shaping and dispersing the laser light collimated by the collimating lens so that chromatic aberration of an optical spot formed on the disk is corrected in which the chromatic aberration is generated by a difference between the wavelengths of the first and second laser lights. The beam-shaped and dispersed first and second laser lights are focused on the disk by an objective lens.

Abstract: A compatible optical pickup capable of recording or reproducing information on or from compact disc (CD) family media such as CD rewritable (CD-RW) and digital versatile disc (DVD) by adopting a stepped planar lens having a plurality of gratings.

Abstract: An optical pickup includes a rotary block rotatably installed on a fixed base; a holder integrally coupled to the rotary block; a bobbin supported by a wires of the holder to be movable; a base plate fixed to the fixed base and placed between the rotary block and the bobbin; an objective lens mounted in the bobbin, for focusing an incident light to form a spot of light on a recording medium; a focusing coil and tracking coils installed in the bobbin, serving as a current flow path for focusing and tracking operations; first magnets and first inner and outer yokes installed in the base plate, facing the focusing coil and the tracking coils, for producing magnetic fields perpendicular to the current flowing through the focusing coil and the tracking coils to produce an electromagnetic force for driving the bobbin; a fixed optical system for irradiating light toward the recording medium and receiving the light reflected by the recording medium and then passed through the objective lens; a reflecting mirror for c

Abstract: An optical pickup device including an objective lens which is compatible with a plurality of optical disks of respectively different specifications, such as a digital versatile disk (DVD), a compact disk-recordable (CD-R) medium, a compact disk (CD) and a laser disk (LD). The optical pickup device includes a laser source to emit light, an objective lens to focus the light emitted from the laser source on respective information recording surfaces of a plurality of optical recording media as an optimal optical spot, and an optical detector to detect light reflected from the information recording surface of the optical recording medium on which the optical spot has been focused and transmitted through the objective lens. The objective lens includes a first lens area, a second lens area, and a third lens area to focus the light emitted from the laser source.

Abstract: An optical recording and reproducing apparatus for adjusting a tilt of an optical pickup in accordance with an amount of jitter of a reproduction signal, a tilt adjusting method therefor, and a recording control method. The optical recording and reproducing apparatus includes an optical pickup having an object lens, a tilt adjusting unit for adjusting a tilt angle of the object lens, a jitter detecting unit for detecting an amount of jitter of a reproducing signal generated by the optical pickup from a disk, and a tilt controlling unit for minimizing the amount of jitter by feeding the amount of jitter detected by the jitter detecting unit back to the tilt adjusting unit. According to the optical recording and reproducing apparatus, there is no need for a space in which a displacement sensor detecting the tilt angle of the optical pickup faces the disk.

Abstract: A recording/reproducing apparatus includes an optical pickup device having an optical phase plate which is compatible with optical recording mediums having different thicknesses, and an optical signal processing device processes information read from the optical recording mediums and processes information to be recorded thereon using the optical pickup device.

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 focusing system which uses a light beam emitted from a light source, includes a refractive surface on one side of the optical focusing system and having a first radius of curvature, a first reflection surface on the above one side, surrounding the refractive surface and having a second radius of curvature being different from the first radius of curvature, a transparent beam focusing surface on the other side of the optical focusing system, and a second reflection surface on the above other side and surrounding the beam focusing surface. The refractive surface refracts an incident light beam, the second reflection surface reflects a light beam refracted by the refractive surface toward the first reflection surface, and the first reflection surface focuses a laser light beam reflected from the second reflection surface on the beam focusing surface as a focused beam spot. The optical focusing system can be used in an optical pickup.

Abstract: A fast responding optical modulating device for a high-density recording using in an optical pickup includes a light source, an optical modulator and a pair of lenses. The pair of lenses are so arranged that the distance between the lenses is shorter than the sum of each focal length of the lenses. The device can adjust an optical spot size at the center of the optical modulator by changing the position of the lenses without altering the whole length between the light source and optical modulator. Therefore, the device can increase the rise time as desired and the optical efficiency in optical modulation for high-density recording which uses a short wavelength light source, and moreover, has an effect of simplifying the high-density recording.

Abstract: An optical pickup includes a variable iris having a numerical aperture is adjusted according to wavelength of light and can be compatibly used for discs having respectively different specifications.

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 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 error signal detecting apparatus for an optical pickup employing a hologram grating, including a sensing lens for focusing light reflected from a recording medium, a hologram grating having first through fourth pattern regions arranged clockwise in a 2.times.

Abstract: A beam-shaping optical system includes a light source, a plurality of plates, and a cylindrical lens disposed between the light source and the plurality of plates, wherein the plurality of plates and the cylindrical lens have an optical feature in which the light output from the light source is beam-shaped to have a desired shape in the cross-section of the light beam. An optical pickup using the beam-shaped light which is diverged by the optical system can obtain convergence light reflected from an optical storage medium. Since the convergence light transmitted through only one plate has astigmatism as it is, a separate lens is not used for light detection and uses a photo detector adapted for employing an astigmatic method, to perform a focussing servo.

Abstract: An optical pickup is used for two kinds of disks, each of which uses a different wavelength of light. The optical pickup includes first and second light sources for individually emitting first and second light beams which have a respectively different wavelength from each other and are identically linearly polarized, a polarizing beam splitter, a quarter-wave plate and a total reflection element.

Abstract: A lens device which can be used as an objective lens in an optical pickup apparatus includes an objective lens provided along a light path facing a disc and having a predetermined effective diameter, and light controlling means provided along the light path for controlling the light in an intermediate region between near and far axes of an incident light beam, thus providing a simplified and inexpensive device for using discs of differing thickness in a single disc drive, by reducing the spherical aberration effect.

Abstract: An optical pickup for correcting an astigmatic difference of a light by using a collimating lens arranged at an angle with respect to the thickness direction of an active layer of a light source and parallel to the width direction of the active layer, for collimating the light emitted from the light source, is provided. The collimating lens is arranged between an edge emitting laser diode having an active layer and a beam splitter, and corrects the astigmatic difference of the light emitted from the edge emitting laser diode. Therefore, a compact optical pickup can be achieved since additional optical elements for correcting the astigmatic difference of the laser beam are not required.

Abstract: An objective lens device having two light control surfaces and an optical pickup able to adopt disks having different thicknesses as a recording medium. The objective lens device includes an objective lens arranged along an optical path parallel to the disks, and first and second control portions formed in a light incident surface of the objective lens, a light emitting surface thereof, or an extra transparent member. Therefore, two disks having different thicknesses are compatible as a recording medium, and light interference occurring when using a thick disk can be decreased.