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: 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: 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: 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.

Abstract: An optical pickup device for a relatively thick disc and/or a relatively thin disk including first and second laser light sources emitting first and second light beams, a first grating splitting the light beams emitted from the second light source, a beam splitter changing optical paths of the light beams emitted from the first and second laser light sources, and an objective lens focusing the light beams passing through the beam splitter onto one of the discs. A photodetector receives and detects the light beams that proceed back after being reflected by one of the discs. A second grating corrects a position of a light spot formed on the photodetector after being reflected by the relatively thin disc or the relatively thick disc, wherein the second grating includes a pattern that is rotated by a predetermined angle with respect to a pattern of the first grating.

Abstract: An optical pickup apparatus includes a light source module which emits a light beam, a beam splitter which reflects or transmits the light beam emitted from the light source module, an objective lens which focuses the light beam passing through the beam splitter onto a disc, and a photodetector which receives and detects the light beam reflected by the disc, wherein the light source module includes a first light source and a second light source that emit first and second light beams having different wavelengths and are formed into a single module. The optical pickup apparatus further includes a first grating which divides the first light beam emitted from the first light source into three beams of the first light beam and transmits the second light beam emitted from the second light source, and a second grating which transmits the first light beam emitted from the first light source and divides the second light beam emitted from the second light source into three beams of the second light beam.

Abstract: An optical pickup apparatus having a beam splitter on which a hologram is formed, and a method of compensating for a deviation between optical axes using the optical pickup apparatus .