Abstract: A projection-type image display apparatus having a structure adapted so that the efficiency of the use of light and resolving power thereof can be enhanced. The projection-type image display apparatus includes a light source; a color separation unit separating incident rays according to predetermined wavelengths, and directing the separated rays at different angles; a lens array dividing the rays separated by the color separation unit into predetermined pixels; a driving portion driving the lens array to change the proceeding paths of the color rays; a polarizing beam splitter changing a proceeding path of incident rays depending on a direction of polarization; a reflection-type display device producing a color image using the rays entering via the polarizing beam splitter, and reflecting the color image toward the polarizing beam splitter; and a projection lens unit magnifying and projecting an incident image onto a screen. In addition, the projection-type image display apparatus may comprise.

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. The inner area, the annular lens area and the outer area have aspherical surface shapes.

Abstract: An optical recording and pickup head having a flat plate lens of a staircase type diffraction grating structure is compatible with a DVD and a CD-RW.

Abstract: A recording/reproducing apparatus having an optical pickup device which is efficient in light use having little spherical aberration.

Abstract: A semiconductor laser for generating a laser beam and an optical pickup for recording/reproducing information using the semiconductor laser as an optical source are provided. The semiconductor laser includes an aperture member on an emitting end thereof to perform high-density memory recording/reproducing through the reduction of an optical spot. The aperture has a hole whose diameter is smaller than the width of the active region of the semiconductor laser, to thereby restrictively emit the laser beam via the hole so that the optical spot formed on an optical disk is reduced. Thus, high-density memory recording/reproducing, which is useful for miniaturized information processors, can be realized.

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 optical pickup assembly having an elastically supported tilt mechanism. The optical pickup assembly includes a bobbin at which an objective lens is mounted and an elastic support member which supports the bobbin in elastic motion with respect to a holder installed at a base. A focus coil and a tracking coil are installed at the bobbin and form a conducting path for driving the objective lens in a focusing direction and a tracking direction. Tilt coils are installed at one side of the bobbin and form a conductive path for driving tilt of the objective lens. A first magnet and a first yoke generate an electromagnetic force to driving the objective lens together with the current carrying focus coil and tracking coil. A second magnet and a second yoke generate an electromagnetic force to driving the objective lens together with the current carrying tilt coils.

Abstract: An optical recording and pickup head having a flat plate lens of a staircase type diffraction grating structure is compatible with a DVD and a CD-RW.

Abstract: An optical pickup assembly includes a base, a bobbin having an objective lens mounted thereon, the bobbin being installed at the base so as to be movable and having a pair of first side surfaces parallel to a radial direction of a disk and a pair of second side surfaces parallel to the tangential direction of a disk track, a focus coil wound around the bobbin for driving the objective lens in a focus direction, a track coil installed at the first side surfaces for driving the objective lens in a radial direction of the disk, a driving magnet installed at the base to face the first side surfaces, a tilt coil installed at the second side surfaces for driving the objective lens in response to the relative inclination between the objective lens and the disk, a first tilt magnet installed at the base such that one polarity thereof faces the tilt coil, a second tilt magnet installed at an upper portion of the first tilt magnet such that another polarity opposite to the one polarity thereof faces the tilt coil, an i

Abstract: A high-density focusing objective lens having a high numerical aperture (NA), which can be easily manufactured by an existing technique, and an optical pickup using the objective lens for high-density recording.

Abstract: An optical pickup device includes a light source for generating and emitting light, optical path changing means for changing a proceeding path of incident light, an objective lens for focusing incident light on a recording medium which has a recording surface where information is recorded and a protection layer, at the side where light is input, for protecting the recording surface, a main photodetector for detecting the information signal and/or an error signal by receiving the light reflected by the recording surface of the recording medium and passing through the objective lens and the optical path changing means, and an inclination detecting unit for detecting inclination of the recording medium by receiving the light emitted from the light source and reflected by the surface of the protection layer or the recording surface of the recording medium.

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 device includes a light source for generating light, a light path changing means for changing the traveling path of incident light, an objective lens for focusing incident light to form a light spot on a recording medium and having an incidence region of a predetermined size, a tracking mirror disposed on the light path between the light path changing means and the objective lens, for reflecting incident light emitted from the light source so that the light spot traces proper track positions of the recording medium, a lens unit consisting of at least two lenses which allow the light reflected from the tracking mirror to be incident on the incidence region of the objective lens, and a photo detecting unit for receiving light reflected from the recording medium and having passed through the objective lens and the light path changing means.

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 recording/pickup head having compatibility with a recordable compact disk (CD-R) and a digital video disk (DVD) transmits a first light beam having a wavelength of 635 nm for a DVD emitted from a first light source and a second light beam having a wavelength of 780 nm for a CD-R emitted from a second light source to an objective lens, using a holographic variable aperture. The holographic variable aperture totally transmits the incident first light beam to the objective lens, and transmits part of the incident second light beam to the objective lens. The objective lens focuses the incident first and second light beams on the information recording surfaces of the CD-R and the DVD. The sizes of the light spots which are focussed on the information recording surfaces of the DVD and the CD-R by the objective lens are approximately 0.9 &mgr;m and 1.4 &mgr;m, respectively, which appropriate for recording and reproducing the respective disks. The light spots have only a main lobe.

Abstract: An optical pickup apparatus compatible with at least two types of optical recording media, using light beams having respective different wavelengths for recording and reading information, the optical pickup apparatus including two laser light sources to emit light beams having the different wavelengths, a holographic lens including a holographic ring to transmit the light beams incident in an inner region of the holographic ring, and to diffract a specific light beam among the light beams emitted from the laser light sources incident in an outer region relative to the inner region, an objective lens to focus the light beams passed through the holographic ring lens on the respective information recording surfaces of the two types of the optical recording media, optical elements to alter optical paths of the light beams reflected from the information recording surfaces of the optical recording media to corresponding photodetectors.

Abstract: A swing-arm type optical recording and reproducing apparatus and an optical disk applicable to the same. The optical disk includes a substrate having an information recording surface to record and reproduce an information signal, and a protective layer which is provided on the information recording surface and whose surface facing a slider is a flat even surface so that variations in a floating height of the slider can be reduced.

Abstract: An optical pickup apparatus compatible with at least two types of optical recording media, using light beams having respective different wavelengths for recording and reading information, the optical pickup apparatus including two laser light sources to emit light beams having the different wavelengths, a holographic lens including a holographic ring to transmit the light beams incident in an inner region of the holographic ring, and to diffract a specific light beam among the light beams emitted from the laser light sources incident in an outer region relative to the inner region, an objective lens to focus the light beams passed through the holographic ring lens on the respective information recording surfaces of the two types of the optical recording media, optical elements to alter optical paths of the light beams reflected from the information recording surfaces of the optical recording media to corresponding photodetectors.

Abstract: An optical pickup compatible with recording media having different formats, the optical pickup includes a light device module having a first light beam source and a second light beam source to emit corresponding first and second light beams having different wavelengths, a hologram light coupler to separately guide the first and second light beams along the same optical path such that the first and second light beams go toward a corresponding one of the recording media, an optical path changing element to selectively alter the optical path of an incident light beam, and an objective lens disposed on an optical path between said optical path changing element the corresponding one of the recording media to focus the first and second light beam on the corresponding one of the recording media, and a photodetector to receive the first and second light beam incident from said optical path changing element.

Abstract: An optical pickup apparatus and method which can selectively perform optical pickup with respect to at least two types of optical disks, on which information recording surfaces are formed, having a different thickness. The optical pickup apparatus includes an optical path alteration unit for altering a path of a light beam so that the light beam emitted from each light source proceeds toward the disk, a numerical aperture adjustment unit, including an annular shielding region which is disposed concentrically about an optical path axis between the optical path alteration unit and the disk supporter, for providing different numerical apertures according to a characteristic of a light beam to be incident; and an objective lens for respectively focusing the light beams having passed through the numerical aperture adjustment unit on the information recording surfaces of the disks to form a beam spot. Accordingly, the apparatus provides a relatively simple structure thereby reducing fabricating cost.