Abstract: An optical pickup actuator comprises a lens holder having an object lens which focuses a laser beam onto an optical information storage medium mounted thereon. In the optical pickup actuator the lens holder is movably supported by a support member with respect to a base. The optical pickup actuator also comprises a magnetic circuit to drive the lens holder in a focusing direction and a tilt direction independently.

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: Disclosed is an optical pickup apparatus. Particularly, a photo detector for use in the optical pickup apparatus detects a beam reflected from the disc, and includes a substrate for transmitting three beams (one main beam and two sub beams) reflected from the optical disc; a liquid crystal for refracting the two sub beams, that are transmitted through the substrate, at different refractive indexes according to the wavelength of a laser beam outputted from the laser diode; an electrode material for supplying power to the liquid crystal; a switch for adjusting the magnitude of an applied voltage to the electrode material; and a photodiode on which the main beam and the refracted sub beams while transmitting the substrate and the liquid crystal are projected, and transformed into electric signals.

Abstract: An optical pickup including an optical member which inhibits interference light reflected from an adjacent layer from being received by a photodetector when an optical information storage medium includes a plurality of recording layers on at least one side thereof. The optical pickup suppresses a photodetector, especially first and second sub-photodetectors of the photodetector, from receiving the interference light reflected from the adjacent layer.

Abstract: An optical pickup actuator having: a moving part on which an objective lens to focus an incident beam onto an optical recording medium is mounted, a magnetic driver that drives the moving part in track and focus directions of the optical recording medium, and a support element that movably supports the moving part and has a first support portion with a first predetermined stiffness and a second support portion with a second predetermined stiffness different from the first predetermined stiffness. A center of gravity of the moving part, a center of support of the support element, and a center of a force determined by arrangement of the magnetic driver are coincident.

Abstract: Disclosed is an optical pickup including a polarization holographic optical element (HOE) and a photodetector. The optical pickup includes a light source, an optical path changer, an objective lens, a polarization HOE, and a photodetector. The polarization HOE has a pattern designed to generate different astigmatisms in the left and right halves of the polarization HOE in a tangential direction and to divide plus and minus first-order beams in a radial direction. The photodetector includes a first light-receiving portion receiving a zero-order beam and second and third light-receiving portion that are disposed on either side of the first light-receiving portion in the tangential direction and respectively receive the plus and minus first-order beams.

Abstract: An optical pickup apparatus and method are provided. The apparatus and method include a light source unit having a holder in which an optical module having first and second light sources for emitting light having different wavelengths and a gating are installed, an optical path changer for changing a path of the light emitted from the first or second light sources, an object lens for focusing light passing through the optical path changer on a relatively thin disc or a relatively thick disc, and a photodetector unit.

Abstract: An optical pick-up apparatus and method incorporating a spherical aberration compensator is disclosed. The optical pick-up employs the spherical aberration device that comprises a wave plate for converting the phase of beams entering the wave plate and outputting the phase-converted beams; and a liquid crystal panel having a molecular structure for adjusting the phase of circularly-polarized beams, whereby it is possible to compensate for the spherical aberrations of the laser beams emitted from a light source and entering an optical recording medium, and the laser beams which are reflected from the optical recording medium and reenter the liquid crystal panel. As a result, jitter characteristic of the optical pick-up can be enhanced.

Abstract: A compatible optical pickup includes a light source which emits a first light beam having a wavelength for a first recording medium; a twin light source which emits second and third light beams respectively having wavelengths for second and third recording media; a first objective lens which condenses the first light beam to form a light spot for recording and/or reproduction of the first recording medium; a second objective lens which condenses the second and third light beams to form light spots for recording and/or reproduction of the second and third recording media; an actuator which drives the first and second objective lenses; a first photo-detector which receives the first light beam reflected from a recording medium to detect an information signal and/or an error signal; and a second photo-detector which receives the second and third light beams reflected from a recording medium to detect information signals and/or error signals.

Abstract: A CD-DVD compatible optical pickup in which both on-axis and off-axis light form a circular light spot on a recording surface of an optical recording medium, and an optical recording and/or reproducing apparatus using the same. The CD-DVD compatible optical pickup includes an optical output module, an objective lens, an optical path conversion unit, a photodetector, and an actuator. The optical output module has a mount and light sources emitting light of different wavelengths. The objective lens focuses the emitted light onto two types of optical recording media. The optical path conversion unit between the optical output module and objective lens, converts incident light. The photodetector receives beams emitted from the light sources, reflected from the optical recording media, and then passed through the optical path conversion unit, detecting data and error signals. The actuator has a movable member, moving the objective lens and compensating focusing and tracking error signals.

Abstract: A method of arranging an optical pickup system on a deck of an optical recording and/or reproducing apparatus, which enables detection of a tracking error signal using one photodetector based on a three-beam method and by a differential phase detection method. The optical pickup system includes a light source, a diffractive optical element which diffracts a light beam incident from the light source and splits the same into at least three beams, a plate-type beam splitter which changes a propagation path of the light beam, and a photodetector including at least one main photodetector having at least four sections and a plurality of sub-photodetectors. The optical pickup system is constructed so as to have a reflecting mirror redirect the propagation path of the light beam emitted from the light source toward a recording medium.