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 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 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.

Abstract: An optical pick-up device is provided that reduces aberrations in light irradiated from an optical recording meidu. The device includes a light source that outputs light for recordation and reproduction of information onto the optical recording medium. An objective lens irradiates the light onto the optical recording medium by concentrating the light. An actuator adjusts the movement of the objective lens to focus the light on at least one or more layers of the optical recording medium. A controller moves the objective lens to substantially reduce the aberration occurring in the light irradiated from the optical recording medium by driving the actuator, such that aberrations, such as asymmetrical aberrations or coma aberrations, may be reduced and corrected.

Abstract: A data line switching circuit of an optical pickup device is disclosed. In order to drive multiple formats of optical disks, the data line switching circuit applies data signals of a corresponding format to the optical pickup device through a common connector by connecting data lines of the corresponding format to the common connector according to control signals from a control unit, thereby minimizing the number of terminals of the connector to obtain a miniaturized optical pickup device.

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 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.

Abstract: Disclosed herein is an apparatus for measuring sub-resonance, which is capable of simultaneously measuring the fundamental frequency characteristics and displacements of an optical pickup actuator through the use of a very simple interferometer. The sub-resonance measuring apparatus of the present invention includes a laser light source, a beam splitter, and an optical detection element. The beam splitter splits light emitted from the laser light source into two light beams. The beam splitter has a reference surface that allows a part of a first beam of the two light beams to be reflected inside of the reference surface and allows the remaining part thereof to pass through the reference surface, and a diffused surface that allows a second beam of the two light beams to be dispersed thereon.

Abstract: An optical pickup is provided which includes a light source and an objective lens for converging incident light from the light source onto a recording medium. The objective lens is arranged to be movable in radial and vertical directions of the recording medium. A holographic optical element (HOE) for changing a traveling path of the incident light is positioned along an optical path between the light source and the recording medium, and has first and second diffraction plates which are divided along a first boundary line and have different diffraction patterns. A photodetector has first and second divided plates which are divided along a second boundary line which is perpendicular to the radial and vertical directions of the recording medium. The first and second divided plates receive light passed through the first and second diffraction plates after being reflected from the recording medium.