Abstract:
A front photo detector (FPD) of an optical pick-up for an optical recording and playing apparatus having no gain selection switch, a simplified configuration, an improved prevention of an abnormal operation due to an error in gain selection, and improved reliability. The front photo detector includes a photo diode unit, a current-voltage amplifying circuit, and a voltage amplifying unit. The photo diode unit outputs current proportional to the power of the light emitted from one of a plurality of laser diodes. The current-voltage amplifying circuit converts the current output from the photo diode unit into a voltage. The voltage amplifying circuit amplifies the voltage output from the current-voltage amplifying circuit by a predetermined gain.
Abstract:
A method and apparatus for compensating tilt. The tilt compensation method includes: obtaining one of a jitter best, an RF envelope, and a focus DC offset (FODC) from a detection signal of the ROM data region and determining whether the obtained value is within a tolerance range; and obtaining an initial skew compensation value using the obtained value when the obtained value is within the tolerance, changing the magnitude of current applied to an actuator designed to perform driving in at least three-axis directions to drive an objective lens of an optical pickup assembly in a radial tilt direction when the obtained value is not within the tolerance range, and repeating the obtaining of one of the jitter best, the RF envelope, and the FODC and changing the magnitude of the current until the obtained value is within the tolerance range.
Abstract:
A compatible optical pickup, including first and second light sources for emitting lights with different wavelengths and first and second photodetectors for detecting an information signal and/or an error signal, and a method of detecting the amount of output light using the compatible optical pickup. The first and second photodetectors monitor the amount of light output from the second and first light sources respectively such that no extra front photodetectors are required. Thus, the number of optical component parts included in the optical pickup can be reduced, thereby lowering the manufacturing costs for the optical pickup. Also, there is no need to secure a space in a base where a front photodetector is to be installed, so the base is simplified. Thus, inferior moldings are reduced, and the durability of a mold can be prolonged.
Abstract:
An optical pickup apparatus and an optical recording/reproducing system including the same, the optical pickup apparatus includes at least two optical systems for different types of optical recording media, one of objective lenses of the optical systems being offset from a central line of the optical recording medium, wherein the optical system including the offset objective lens having a diffraction grating diffracting light emitted from a light source to form a main beam and sub-beams, wherein the diffraction grating includes first and second diffraction regions having different grating patterns arranged alternately thereon, and a center of each sub-beam is arranged at a boundary of the first and second diffraction regions of the diffraction grating, and a center of the diffraction grating and an optical axis of the light source are adjusted to be coincided with each other, preventing generation of an alternating current in a Push-Pull signal of the sub-beams.
Abstract:
An optical recording/reproducing apparatus includes an optical pickup and a signal processor. The optical pickup includes an optical splitting device which splits light emitted from a first light source into a main light beam and sub-light beams which are symmetrical with respect to the main light beam and irradiates the split light beams on a recording medium, and a light detection device which receives the main light beam and the sub-light beams reflected by the recording medium, so as to detect a tracking error signal in a three-beam method and one of a push-pull method and an improved push-pull method. The signal processor receives the detection signals output by the light detection device and detects the tracking error signal in the three-beam method and one of the push-pull method and the improved push-pull method, and otherwise selectively detects the tracking error signal in one of the three-beam method, the push-pull method and the improved push-pull method, so as to realize an optimal tracking servo-control. Since a selective use of one of the improved push-pull method, the push-pull method and the three-beam method can be made according to the type of an optical disc, the optimal tracking servo-control can be realized regardless of the depth of a pit in an optical disc during a reproduction of data from the optical disc, such as a non-rewritable optical disc.
Abstract:
An optical pickup using a two-wavelength light source module includes a light source module, a collimating lens, and a first optical element. The light source module includes first and second light sources which emit first and second light beams of different wavelengths and are formed in a single package. The collimating lens directs the first and/or second light beams into convergent light or divergent light so that the convergent light or the divergent light is incident on the objective lens. The optical pickup is a finite optical system due to the collimating lens. The first optical element is disposed on the traveling paths of the first and second light beams, operates as a lens only for one of the first and second light beams, and corrects a position difference between the first and second light sources along a traveling direction of light. The optical pickup further includes a second optical element which is disposed on the traveling paths of the first and second light beams and matches traveling optical axes of the first and second light beams with each other.
Abstract:
An optical pickup actuator including a multi-conductive suspension. The optical pickup actuator may include a base, a holder fixed to the base, a bobbin holding an object lens and having a plurality of driving coils, and a plurality of suspensions connected between the bobbin and the holder and movably supporting the bobbin toward the holder, wherein each of the suspensions may be a multi-conductive suspension including a flexible substrate and a plurality of wires, formed on the flexible substrate, applying currents to the coils.
Abstract:
A lens device which can be used as an objective lens in an optical pickup apparatus includes an objective lens provided along a light path facing a disc and having a predetermined effective diameter, and light controlling means provided along the light path for controlling the light in an intermediate region between near and far axes of an incident light beam, thus providing a simplified and inexpensive device for using discs of differing thickness in a single disc drive, by reducing the spherical aberration effect.
Abstract:
A slim optical pickup apparatus which records/reads information from a recording medium includes a light source, an objective lens which focuses a beam incident from the light source on the recording medium, an optical device which is provided on an optical path between the light source and the objective lens, and converts the beam incident from the light source into a parallel beam, an optical axis shifting unit which is provided on an optical path between the optical device and the objective lens, and shifts an optical axis of the parallel beam passing through the optical device in parallel in a direction, a reflecting mirror which is provided on an optical path between the optical axis shifting unit and the objective lens, and reflects the parallel beam passing through the optical axis shifting unit toward the recording medium, and a photodetector which receives a beam reflected from the recording medium and passed through the optical axis shifting unit, and performs a photoelectric conversion. Use of the optical path shifting unit reduces the height of an optical pickup apparatus, thereby providing a slim optical pickup apparatus using an existing light source and photodetector of a conventional size.
Abstract:
A compatible type optical pickup using a wedge type beam splitter that can record and/or reproduce information on/from optical recording media having different formats. The compatible type optical pickup includes: a first light source that generates and emits a first light beam of a predetermined wavelength; a second light source that generates and emits a second light beam having a different wavelength from that of the first light beam; a wedge type beam splitter disposed in an optical path between the first and second light sources, which changes the traveling paths of the first and second light beams to allow the first and second light beams to travel along the same optical path and minimizes aberrations; a main beam splitter disposed in an optical path between the wedge type beam splitter and an optical recording medium, which changes the traveling paths of incident light beams; an objective lens that focuses the first and second light beams entered via the main beam splitter onto the optical recording medium; and a main photodetector that receives the first and second light beams reflected from the optical recording medium detects an information signal and an error signal.