Abstract: An optical pickup compatible with recording media having different formats, the optical pickup includes a light device module having a first light beam source and a second light beam source to emit corresponding first and second light beams having different wavelengths, a hologram light coupler to separately guide the first and second light beams along the same optical path such that the first and second light beams go toward a corresponding one of the recording media, an optical path changing element to selectively alter the optical path of an incident light beam, and an objective lens disposed on an optical path between said optical path changing element the corresponding one of the recording media to focus the first and second light beam on the corresponding one of the recording media, and a photodetector to receive the first and second light beam incident from said optical path changing element.

Abstract: An optical pickup includes a laser light source, an objective lens which focuses light emitted from the laser light source on an optical information storing medium, an optical path changer which changes a proceeding path of the light emitted from the laser light source, a polarization changer which changes the polarization of an incident light to make the polarization of light reflected by the optical information storing medium and reentering the laser light source different from that of the light emitted from the laser light source, so that noise generated due to interference by the light reflected by the optical information storing medium and reentering the laser light source is reduced, and a photodetector which receives incident light reflected by the optical information storing medium and sequentially passing through the objective lens and the optical path changer and detects an information signal and/or an error signal.

Abstract: A method and an apparatus for identifying the type of an optical recording medium are provided. The method includes detecting a surface reflected signal SS and a writable-surface reflected signal SR of an optical recording medium while performing a focus search using a first optical system, counting a time difference DTS between a high peak and a low peak of the surface reflected signal SS, counting a time difference DTR between the high peak of the surface reflected signal and a high peak of the writable-surface reflected signal SR, obtaining DT by substituting DTR and DTS into the following equation: DT = ( DT R ) a ( DT S ) b ? ? ( a - b ? 1 2 ) and comparing DT with a reference time T, and driving the first optical system if DT is greater than T and driving a second optical system if DT is not greater than T.

Abstract: An optical pickup compatible with recording media having different formats, the optical pickup includes a light device module having a first light beam source and a second light beam source to emit corresponding first and second light beams having different wavelengths, a hologram light coupler to separately guide the first and second light beams along the same optical path such that the first and second light beams go toward a corresponding one of the recording media, an optical path changing element to selectively alter the optical path of an incident light beam, and an objective lens disposed on an optical path between said optical path changing element the corresponding one of the recording media to focus the first and second light beam on the corresponding one of the recording media, and a photodetector to receive the first and second light beam incident from said optical path changing element.

Abstract: An optical pickup compatible with recording media having different formats, the optical pickup includes a light device module having a first light beam source and a second light beam source to emit corresponding first and second light beams having different wavelengths, a hologram light coupler to separately guide the first and second light beams along the same optical path such that the first and second light beams go toward a corresponding one of the recording media, an optical path changing element to selectively alter the optical path of an incident light beam, and an objective lens disposed on an optical path between said optical path changing element the corresponding one of the recording media to focus the first and second light beam on the corresponding one of the recording media, and a photodetector to receive the first and second light beam incident from said optical path changing element.

Abstract: Provided is a laser diode driving circuit which prevents low optical output power of a laser diode at high ambient temperature, and prevents damage to the laser diode at low ambient temperature by adjusting the limit of a laser diode driving current, which is input to a laser diode, based on an optical output power characteristic that decreases optical output power as the ambient temperature decreases. Such a laser diode driving circuit includes a laser diode driving unit, which outputs a laser diode driving current and a laser diode protection unit, which sets the limit of the laser diode driving current output from the laser diode driving unit and increases the limit of the laser diode driving current as the ambient temperature of the laser diode increases.

Abstract: An optical pickup includes a laser light source, an objective lens which focuses light emitted from the laser light source on an optical information storing medium, an optical path changer which changes a proceeding path of the light emitted from the laser light source, a polarization changer which changes the polarization of an incident light to make the polarization of light reflected by the optical information storing medium and reentering the laser light source different from that of the light emitted from the laser light source, so that noise generated due to interference by the light reflected by the optical information storing medium and reentering the laser light source is reduced, and a photodetector which receives incident light reflected by the optical information storing medium and sequentially passing through the objective lens and the optical path changer and detects an information signal and/or an error signal.

Abstract: A method and an apparatus for identifying the type of an optical recording medium are provided.

Abstract: An optical pickup device includes a light source for emitting light, a beam splitter installed on an optical path of the light emitted from the light source for splitting the light, an objective lens for focusing a main light split by the beam splitter at an optical disk, a monitoring photodetector for receiving a sub-light split by the beam splitter and monitoring the amount of light output from the light source, a main photodetector for receiving the light emitted from the light source and reflected by the optical disk and passing through the beam splitter and detecting an error signal and an information signal, and a collimating lens installed on the optical path between the light source and the beam splitter for focusing both the main light and sub-light split by the beam splitter, so that the amount of light received by the monitoring photodetector increases.

Abstract: A compatible optical pick-up device includes a first light source to emit a first light, a second light source to emit a second light and having a wavelength that is different from that of the first light, a first optical path converter to reflect the first light irradiated from the first light source onto an optical path, a second optical path converter to reflect the first light from the first optical path converter and transmit the second light irradiated from the second light source onto the optical path, an objective lens to converge the light received from the second optical path converter towards an optical recording medium, and a photo-detector to receive an incident light reflected by the optical recording medium. The compatible optical pick-up device reduces the difference between transmissivities depending on the polarization status of the incident light by adopting a transmission-type optical path converter such that the optical recording medium is minimally affected by the birefringence.

Abstract: A method of controlling a balance of a photodetector capable of increasing light reception efficiency thereof in a compatible optical pickup and an apparatus thereof. The method includes installing first and second light sources in a single module; directing light supplied from the first or second light source and transmitted through a holographic optical element, an optical path changing unit, and an objective lens onto a disk corresponding to each light source, transmitting the light reflected from the disk through the objective lens, and the optical path changing unit to a photodetector, moving the photodetector so that the center of a first one of first and second spots received by the photodetector is concentric with the center of the photodetector; and moving the holographic optical element so that the center of the second received spot from the second light source is concentric with the center of the photodetector.

Abstract: An optical pickup compatible with recording media having different formats, the optical pickup includes a light device module having a first light beam source and a second light beam source to emit corresponding first and second light beams having different wavelengths, a hologram light coupler to separately guide the first and second light beams along the same optical path such that the first and second light beams go toward a corresponding one of the recording media, an optical path changing element to selectively alter the optical path of an incident light beam, and an objective lens disposed on an optical path between said optical path changing element the corresponding one of the recording media to focus the first and second light beam on the corresponding one of the recording media, and a photodetector to receive the first and second light beam incident from said optical path changing element.

Abstract: A compatible optical pickup capable of recording or reproducing information on or from compact disc (CD) family media such as CD rewritable (CD-RW) and digital versatile disc (DVD) by adopting a stepped planar lens having a plurality of gratings.

Abstract: An optical pickup apparatus for an optical disk having multiple recording layers. Said apparatus includes a fixed optical system for emitting light toward the optical disk and receiving light reflected from the optical disk, a spot forming device for focusing light emitted from the fixed optical system to form a beam spot on the optical disk, and a spot zooming device for zooming the beam spot formed by the spot forming means onto a desired recording layer selected from the multiple recording layers of the optical disk.