摘要:
A compatible optical pick-up apparatus, which records to and/or reproduce from both digital versatile disc (DVD)-type optical disks and compact disc (CD)-type optical disks for improving a signal regeneration capacity and a tracking capacity in operation at a high temperature. A polarized hologram of the optical pick-up apparatus is divided into six diffraction regions. The rays of a first light diffracted at the first and second diffraction regions are separately received by divided parts of a first bisected light-receiving portion of a photodetector.
摘要:
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.
摘要:
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.
摘要:
A compatible optical pickup apparatus and method are provided. The apparatus and method include a first light source for generating and emitting a first light having a predetermined wavelength, a second light source for generating and emitting a second light having a wavelength different from the wavelength of the first light, a beam shaping beam splitter provided in paths of the first and second lights for shaping the first and second lights in order to change a shape of a profile of each of the first and second lights to a circular shape and change the paths of the first and second lights, an objective lens for focusing the first and second lights and forming light spots on an optical recording medium, and a main photodetector for receiving the first and second lights by being reflected from the optical recording medium and passing through the objective lens and the beam shaping beam splitter, and detecting an information signal and an error signal.
摘要:
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.
摘要:
A method of reproducing information from an optical disc, and an optical disc reproducing apparatus using the method, including reproducing information from an optical disc having a plurality of regions with differing physical specifications, the information is read using optical beams having differing spot sizes in regions of the optical disc having differing physical specifications. The method enables the optical disc having the regions with differing physical specifications to stably reproduce information from all regions of the optical disc by minimizing regional reproduction performance differences caused in the reproduction process.
摘要:
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 that emits short wavelength light which is focused onto an optical recording medium by the first and second objective lenses, a first photodetector that receives a returning reflected light from the optical recording medium, and a first optical path converter for selectively guiding part of the light emitted from the first light source towards the first or the second objective lens, and guiding the reflected light towards the first photodetector.
摘要:
A compatible optical pickup apparatus and method are provided. The apparatus and method include a first light source for generating and emitting a first light having a predetermined wavelength, a second light source for generating and emitting a second light having a wavelength different from the wavelength of the first light, a beam shaping beam splitter provided in paths of the first and second lights for shaping the first and second lights in order to change a shape of a profile of each of the first and second lights to a circular shape and change the paths of the first and second lights, an objective lens for focusing the first and second lights and forming light spots on an optical recording medium, and a main photodetector for receiving the first and second lights by being reflected from the optical recording medium and passing through the objective lens and the beam shaping beam splitter, and detecting an information signal and an error signal.
摘要:
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.
摘要:
An optical axis alignment apparatus of an optical pick-up device for measuring and adjusting a shift amount between a central axis of an objective lens and an optical axis of a laser beam emitted from a light source includes a first photodetector positioned to reciprocate along a central axis of the objective lens, for detecting a shift amount of an optical axis of the laser beam with respect to the central axis of the objective lens and for generating a first detection signal; a second photodetector for detecting a distribution of the laser beam emitted from the laser source and for generating a second detection signal; a beam splitter for splitting the laser beam at a predetermined angle to direct the laser beam to said first and said second photodetectors, respectively; a driving mechanism for reciprocating the first photodetector along the central axis of the objective lens; and mechanism for adjusting the position and the angle of the laser source in dependence upon reception of the first and second detection signals.