Abstract: A method for manufacturing a gas diffusion layer for a fuel cell wherein carbon nanotubes are impregnated into Korean paper, thereby enhancing electroconductivity, and a gas diffusion layer manufactured thereby. The method for manufacturing a gas diffusion layer for a fuel cell which is to manufacture a gas diffusion layer as a constituent member of a unit cell in a fuel cell, includes a support preparation step of preparing a support with Korean paper; a dispersion preparation step of dispersing a carbon substance in a solvent to form a dispersion, a coating step of coating the support with the dispersion, and a thermal treatment step of thermally treating the dispersion-coated support to fix the carbon substance to the support.

Abstract: An objective lens for optical pickup and an optical pickup apparatus having the same are provided. The objective lens for optical pickup includes a light source side lens surface and a disc side lens surface. The light source side lens surface and the disc side lens surface each include an effective region disposed at a central region of the objective lens and a non-effective region disposed outside the effective region. An optical path changing element, disposed in the non-effective region of at least one of the light source side lens surface and the disc side lens surface, changes a path of light incident thereon.

Abstract: An objective lens for optical pickup and an optical pickup apparatus having the same are provided. The objective lens for optical pickup includes a light source side lens surface and a disc side lens surface. The light source side lens surface and the disc side lens surface each include an effective region disposed at a central region of the objective lens and a non-effective region disposed outside the effective region. An optical path changing element, disposed in the non-effective region of at least one of the light source side lens surface and the disc side lens surface, changes a path of light incident thereon.

Abstract: An optical pickup device is provided. The device includes a semiconductor laser light source which outputs linearly-polarized light having an elliptical shape, an objective lens which focuses light outputted from the semiconductor laser light source, forming an optical spot on an optical disc; and a polarization plate which is disposed placed on an optical path between the semiconductor laser light source and the objective lens, and which polarizes the light outputted from the semiconductor laser light source and transmits elliptically-polarized light, wherein the polarization plate is disposed such that a major axis of the elliptical polarization of the light transmitted by the polarization plate is parallel to or perpendicular to a major axis of the elliptical shape of the light.

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: A photodetector detecting reflected light components from an optical medium, the photodetector including a first detector divided into eight sections detecting the reflected light components and converting the light components into electrical signals, a first calculating portion calculating a first tracking error signal from the electrical signals by a differential push-pull method, a second calculating portion calculating a first focusing error signal by an astigmatism method and calculating a second tracking error signal by a differential phase detection method from the electrical signals converted by the first detector; a second detector divided into four sections detecting the reflected light components reflected by the optical recording medium to convert the light components into electrical signals; and a third calculating portion calculating a second focusing error signal by the astigmatism method and calculating a third tracking error signal by the differential phase detection method from the electrica

Abstract: An optical pickup apparatus includes a light generating unit to generate a light to record or reproduce information, an objective lens to focus the light generated from the light generating unit onto a disk, and a multi-sectional polarizer disposed on a light path between the light generating unit and the objective lens and divided into a plurality of sectors having their individual optical axes.

Abstract: An optical pickup includes a collimator lens having a diverging lens and a converging lens, such that it maintains a constant focal length and has a short optical path length. The collimator lens of the optical pickup device includes a diverging lens located at the side of a light source and a converging lens located at the side of generating parallel light or gentle oscillation light. In addition, the diverging lens and the converging lens of the collimator lens may be integrated, or may also be formed of a hologram optical element. As a result, the optical pickup device can be configured in the form of a slim structure using the collimator lens having a short optical path length.

Abstract: An optical pickup device, which reduces the size of an optical spot formed on an optical disk, and prevents the degradation of a tracking error signal due to coherent light from a layer adjacent a target recording/reproducing layer of the optical disk. The optical pickup device includes a light source emitting light at a designated wavelength; an object lens concentrating the light incident from the light source thereupon and forming an optical spot on an optical disk having multiple recording layers; and an optical detector receiving the light reflected by the optical disk and detecting a data signal and an error signal, wherein at least one diffraction pattern region partially diffracting or intercepting the light, emitted from the light source and being incident upon the object lens, and the light, reflected by optical disk and being incident upon the object lens, is formed on the object lens.

Abstract: An optical pickup actuator independently drivable in focusing, tilting and tracking directions. The optical pickup includes a lens holder movably installed on a base, and mounted with an objective lens for transmitting an incident light to an optical information recording medium; and a magnetic circuit to independently driving the lens holder in the focusing, tilting and tracking directions. The magnetic circuit includes opposing magnets; a focusing coil and tilting coils interposed between the magnets, mounted inside the lens holder, and wound around respective axes parallel to the focusing direction; and a plurality of tracking coils mounted outside the lens holder, interposed between the magnets and wound around respective axes transverse to the focusing direction. The magnetic fields of the magnets are guided by outer yokes partially encompassing the magnets and inner yokes positioned within the focusing coil and the tilting coils.

Abstract: An optical pickup apparatus includes a light generating unit to generate a light to record or reproduce information, an objective lens to focus the light generated from the light generating unit onto a disk, and a multi-sectional polarizer disposed on a light path between the light generating unit and the objective lens and divided into a plurality of sectors having their individual optical axes.

Abstract: An optical pickup apparatus includes a first objective lens having a low numerical aperture (NA) suitable for a low-density recording medium, a second objective lens having a high NA suitable for a high-density recording medium, a first light source to generate a short-wavelength optical signal to use the first and second objective lenses, a first photo-detector to receive an optical signal, which is generated from the first light source, is focused on a recording medium by the first and second objective lenses, and is then reflected from the recording medium, and a beam splitter to perform a division of the optical signal generated from the first light source, to direct some parts of the divided optical signal to the first objective lens, and to direct the other parts of the divided optical signal to the second objective lens.

Abstract: An optical pickup device according to an embodiment of the present invention comprises a light source for projecting a beam of light to record and reproduce information with respect to an optical recording medium. A collimating lens is disposed on a path of the light to converge and convert the light into a parallel beam. An object lens condenses the parallel beam from the collimating lens and projects the parallel beam onto the optical recording medium. An optical element is disposed between the collimating lens and the object lens. A first actuator moves the collimating lens along the optical axis to thereby control a distance between the collimating lens and the optical element. A first controller drives the first actuator to find a position for the collimating lens, for reducing aberration generated in the light being projected to the optical recording medium. Accordingly, the aberration can be effectively prevented, thereby improving recording and reproducing performance of the optical pickup device.

Abstract: An optical pickup apparatus is provided for use in a recording/reproducing apparatus to record/reproduce information on/from recording media having different formats. Such an optical pickup apparatus comprises a dual wavelength laser diode; a hologram module arranged to split a light which is incident to a recording medium into a plurality of beams; and a photo-detector arranged to receive a light beam reflected from the recording medium and detect an information signal and a signal for servo control. Each of the split beams is focused on a predetermined position corresponding to a format of the recording medium. The light beams reflected from the recording medium are detected by the photo-detector to generate a focus error signal and a tracking error signal. Thus, the optical pickup apparatus records and reproduces information on and from recording media having different formats by using a hologram of a simple pattern.

Abstract: An object lens for an optical disk may include an aspherical lens surface, and an aspherical equation, which may be applied to form the aspherical lens surface may include two 2nd order function terms. Accordingly, a lens, which has a high numerical aperture (NA) and also has a small flexure on a lens surface or aberration, is provided.

Abstract: An optical pickup which is compatible with different types of media is disclosed. A plurality of light sources emit light with different wavelengths. Light path changers change the path of light emitted by the plurality of light sources so that the light is incident upon an objective lens. The objective lens focuses the incident light onto a recording medium. A collimating lens is disposed in front of the objective lens to collimate the incident lights. The collimating lens is movable to correct a spherical aberration. A diffractive optical element is disposed in a path of a light with a short wavelength and has a diffractive surface to correct a chromatic aberration.

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 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 photo-curable adhesive composition including an oligourethane acrylate in a range of about 10 to about 30% by weight, a reactive monomer-diluent in a range of about 32 to about 46% by weight, a polymeric filler in a range of about 20 to about 30% by weight, a photoinitiator in a range of about 2.5 to about 5.0% by weight, an antioxidant in a range of about 0.005 to about 0.02% by weight, a chlorinated polyvinyl chloride in a range of about 3.0 to about 10%, the chlorinated polyvinyl chloride having a chlorine content of about 62 to about 64% by weight, oxalic acid in a range of about 0.3 to about 2.0% by weight, a thixotropic agent in a range of about 0.5 to about 3.0% by weight, and a plasticizer in a range of about 1.0 to about 10.0% by weight, based on the total weight of the composition.