Abstract: An aspheric lens includes at least one aspheric lens surface, and an angle of inclination on the aspheric lens surface is smaller than or equal to 65°. The aspheric lens surface is given by the equation Z ? ( r ) = cr 2 1 + 1 - ( 1 + K ) ? c 2 ? r 2 + Lr 2 + Ar 4 + Br 6 + Cr 8 + Dr 10 + Er 12 + Fr 14 + Gr 16 + Hr 18 + Jr 20 where L?0, c is a curvature, r2=x2+y2, K is a conic integer, and L and A through J are aspheric coefficients.

Abstract: An optical recording/reproducing apparatus, medium, and method and a controlling apparatus, medium, and method thereof. The recording/reproducing apparatus includes an optical pickup actuator including a holder formed on a base, a blade connected to the holder with a plurality of elastic supporters, a pair of focus coils for operating the blade in a focus direction, track coils for operating the blade in a tracking direction, magnets, a memory for storing a lookup table for the height of the blade according to electric current, a lookup table for the tilt of the blade according to the electric current supplied to the focus coils, a lookup table for the actual tilt of an optical disk according to the height of the blade, and a controller for computing a tilt difference between the optical disk and the blade and controlling the electric currents supplied to the focus coils to compensate for the tilt difference.

Abstract: An optical pickup apparatus includes a light source to emit light of a predetermined wavelength, an objective lens to focus the light emitted from the light source to form a light spot on an optical disc having a plurality of recording layers, a photodetector to detect a signal and an error signal by detecting the light reflected from the optical disc, and a light scattering portion to reduce an amount of the light reflected from a non-target layer of the recording layers and incident on the photodetector by scattering part of the light reflected from the optical disc during a reproduction of data from the optical disc.

Abstract: An optical pickup apparatus and method for recording and/or reproducing information onto and/or from optical discs having diverse specifications. Particularly, a diffraction grating for use in the optical pickup apparatus includes a substrate for refracting an output beam from a laser diode at a predetermined refractive index, a liquid crystal for refracting the beam, which is transmitted through the substrate, at a different refractive index and direction according to a track pitch of the optical disc, an electrode material for supplying power to the liquid crystal, and a switch for controlling power supply to the electrode material. Electrode materials are aligned with various spacing in order to change the refractive index of the liquid crystal according to the wavelength of a laser and the specification of an optical disc used. Also, power supply to the electrode materials is controlled depending on the optical disc specification.

Abstract: An optical pickup apparatus includes an objective lens that focuses light on an optical recording medium; an actuator that drives the objective lens in a direction of an optical axis of the objective lens toward or away from an optical recording medium in response to an input voltage applied to the actuator; an actuator driven distance sensor that senses a distance the actuator moves according to time or the input voltage applied to the actuator; an input voltage calculator that calculates an input voltage to be applied to the actuator that compensates for a hysteresis phenomenon that occurs during movement of the actuator based on the distance sensed by the actuator driven distance sensor; and a controller that controls operation of the actuator according to the input voltage calculated by the input voltage calculator.

Abstract: A diffraction element for an optical pick-up apparatus is capable of precisely controlling the tracking of the pick-up apparatus. The diffraction element includes a diffraction grating divided into a first, a second, and a third region. The second region is located between the first and third regions. Any one of the first region and the third region is inclined at a predetermined angle ? with respect to the second region.

Abstract: A photosensitive composition, which has a cross-linking monomer having at least two ethylenic double bonds, a photopolymerization initiator, and an organic solvent, and a method of preparing a barrier rib for a plasma display panel, wherein the photosensitive composition is used. The photosensitive composition provides improved adherence to an inorganic material and an organic material.

Abstract: An optical pickup apparatus according to an embodiment of the present invention, comprises an optical unit for projecting a plurality of wavelengths of light, the light including a celadon light, toward a recording medium and receiving the light reflected from the recording medium to thereby detect an information signal and an error signal, and a compatible objective lens for focusing a light projected from the optical unit to thereby form an optical spot on a recording surface of the recording medium and applying at least three light having different wavelength ranges to be compatibly used for both the high-density and the low-density recording mediums. Accordingly, the optical pickup apparatus is capable of compatibly employing a high-density recording medium, which uses a celadon light and is slimmer than a digital versatile disc (DVD), and at least one low-density recording medium.

Abstract: A diffraction element for use in an optical pick-up is capable of calculating a TE signal more stably irrespective of any assembly error in optical elements. The diffraction element of the invention is divided into three areas, a first, a second, and a third area. Each area comprises a diffraction grating with a predetermined period, and the second area is provided between the first area and the third area. The diffraction grating of the first area is substantially parallel to the diffraction grating of the third area, and the diffraction grating of the second area is substantially perpendicular to the diffraction gratings of the first and the third area.

Abstract: An optical recording/reproducing apparatus including a plurality of light sources emitting lights with different wavelengths for use in recording/reproducing information onto/from various types of optical recording media of different recording densities, in which at least two lights emitted from the light sources have polarization components orthogonal to each other; an objective lens for focusing a light from each of the light sources to a corresponding optical recording medium; a collimating lens disposed between the light sources and the objective lens for collimating lights from the light sources; a hologram element installed between the collimating lens and the objective lens for refracting a light emitted from one of the light sources, in which the light to be refracted is selected by wavelength and polarization components; and a photodetector receiving a light that is reflected from the corresponding optical recording medium after being focused by the objective lens.

Abstract: A diffraction element for an optical pick-up apparatus is provided that enables more accurate focusing control. The diffraction element for an optical pick-up apparatus is divided into first and second regions, each being formed with a grid pattern in which grids are repeated with a predetermined pitch P. The grid pattern in at least one of the first and second regions is tilted by a predetermined angle with respect to a virtual line VL substantially perpendicular to a division line DL that divides the first and second regions.

Abstract: A photosensitive composition, which has a cross-linking monomer having at least two ethylenic double bonds, a photopolymerization initiator, and an organic solvent, and a method of preparing a barrier rib for a plasma display panel, wherein the photosensitive composition is used. The photosensitive composition provides improved adherence to an inorganic material and an organic material.

Abstract: An optical pickup which is compatible with at least one high density recording medium that uses a blue-violet beam and at least one lower density recording medium, the optical pickup including: an optical unit to selectively emit one of a plurality of beams with different wavelengths onto one of the at least one high density recording medium and the at least one lower density recording medium, and to receive the respective beam reflected from the respective recording medium; and a holographic objective lens to focus the respective beams emitted by the optical unit on a recording surface of the respective recording medium, the holographic objective lens including a first holographic lens region and a second holographic lens region located inside the first holographic lens region, wherein holographic patterns of the first and second holographic lens regions respectively produce a first effective numerical aperture (NA) for the at least one high density recording medium and at least one additional effective NA s

Abstract: The present invention relates to a photosensitive resin composition, a preparation method thereof, and a dry film resist comprising the same. More particularly, the photosensitive resin composition of the present invention is directed to a photosensitive resin composition including a) an alkali-soluble acrylate resin, b) a cross-linking monomer having at least two ethylenic double bonds, and c) a phosphinoxide based photopolymerization initiator and an acridon based photopolymerization initiator. According to the photosensitive resin composition and the dry film resist, it is easy to finely pattern using a laser direct image (LDI) with high density and the dry film has excellent sensitivity, resolution, and adhesiveness to the substrate.

Abstract: An optical pickup apparatus for reading and writing information from and to optical data media in different formats and a method thereof are provided. The optical pickup apparatus comprises a twin laser diode (Twin LD), a diffraction element for dividing a laser beam incident on a data medium into five beams, and an optical detector for focusing a laser beam reflected from the data medium to detect an information signal and signals for carrying out servo controls. The divided beams are focused on a predetermined location in based on a data medium format, and the beam reflected from the data medium is received on and detected from the corresponding photodiodes of the optical detector so that a focus error signal and a tracking error signal are generated.

Abstract: An optical pick-up and a disc apparatus having the same to overcome an inferiority of a tracking signal caused by an adjacent layer during the recording and/or reproducing of data an optical disc with multiple recording layers are provided, the optical pick-up including: a light source to emit a light with a predetermined wavelength corresponding to a type of the optical disc; a light collecting unit to focus the emitted light to form a light spot on a signal recording layer of the optical disc, wherein the signal recording layer reflects the light as a signal light and an adjacent layer of the optical disc reflects the light as a noise light; a photodetector to detect a signal by receiving the signal light; and an optical member to intercept the noise light in order to decrease an intensity of the noise light entering the photodetector.

Abstract: An optical pickup which can remove birefringence due to the non-uniformity of an optical recording medium by using a polarization beam splitter. The optical pickup includes a light source emitting a laser beam, a beam splitter reflecting part of incident light and straight transmitting the remaining light to change a proceeding path of the incident light, an objective lens focusing the incident light passed through the beam splitter to form a light spot on an optical recording medium, a polarization beam splitter arranged on an optical path between the beam splitter and the objective lens for transmitting light having one polarization and reflecting light having a different polarization.

Abstract: A light emitting module and method and an optical pickup apparatus employing the same are provided. The light emitting module includes a base, a semiconductor laser that is disposed on the base and emits a laser beam of a predetermined wavelength, a cap surrounding the semiconductor laser, a beam shaping window that is fitted with a predetermined portion of the cap corresponding to the propagation path of the laser beam and shapes a transmitted laser beam while reflecting a portion of an incident beam, and a quarter wave plate that is disposed in the propagation path of the laser beam and in front of the beam shaping window and transforms a laser beam horizontally polarized after passing through the beam shaping window into a circularly polarized beam while converting a beam reflected from an optical disc into a vertically polarized beam.

Abstract: An optical pickup includes an optical module that detects an information signal and/or an error signal by radiating light to a recording medium and receives light reflected by the recording medium. The optical module includes a light source; an optical path changer that changes a path of light emitted from the light source; a main photodetector that receives light that is reflected off a recording medium back to the optical module to detect an information signal and/or an error signal; and a hologram element that generates an astigmatism of the light incident onto the optical module. Since most optical elements of the optical pickup except an objective lens are packaged in the optical module, the entire structure of the optical pickup can be simplified and the number of bonding points for fixing the optical elements of the optical pickup on a base can be reduced.

Abstract: An optical pick-up and a disc apparatus having the same. The inferiority of a tracking signal caused by an adjacent layer during the recording and/or reproducing of an optical disc with multiple recording layers is effectively prevented. The optical pickup includes a light source to emit light with a predetermined wavelength, a light collecting unit to collect the light emitted from the light source to form a light spot on a signal recording layer of an optical disc having a plurality of recording layers, a photodetector to receive the light reflected by the optical disc to detect a signal, and an optical member to change the optical transmission of the light reflected by the optical disc according to an incident angle of the reflected light to decrease an optical transmission of a noise light entering the photodetector.