7 results about "Optical pickup" patented technology

In the optical pickup device, while reflection light reflected from the optical multi-layer disc is divided into a plurality of regions so as to produce a plurality of divided optical beams, the divided optical beams are focused onto different positions on a photodetector, and a focus error signal is detected by employing a plurality of the divided optical beams by utilizing the knife edge method, and further, a tracking error signal is detected by employing a plurality of the divided optical beams. Furthermore, the dividing regions of the optical beam and light receiving parts are arranged in such a manner that stray light derived from other layers of the optical disc is not entered to a servo signal-purpose light receiving part of the photodetector when the divided optical beam is focused onto a target layer of the optical disc.

An optical pickup apparatus has a semiconductor laser source which emits a laser beam in a wavelength band of 405 nm having an elliptic light intensity distribution; a beam shaping element which shapes the light intensity distribution of the laser beam; a polarizing beam splitter having a polarized light separation film in contact with the air and reflecting the laser beam shaped by the beam shaping element on the polarized light separation film; and an objective lens which focuses the laser beam reflected on the polarized light separation film onto an optical information recording medium.

The objective lens driving device of the present invention for an optical pickup device is provided. The device includes first and second objective lenses, and a lens holder for supporting the first and second objective lenses. The lens holder has a first through-hole for passage of first laser beam and a second through-hole for passage of second laser beam. Where a plane defined by a central axis of the first objective lens and a central axis of the second objective lens is a central plane, a plane perpendicular to the central plane and including the central axis of the first objective lens is a first plane, and a plane perpendicular to the central plane and including the central axis of the second objective lens is a second plane; the first through-hole is asymmetrical with respect to the first plane and/or the second through-hole is asymmetrical with respect to the second plane.

A lens moving apparatus of the present invention is used in an optical pickup of, for example, an optical recording/reproducing system. The apparatus includes a moving assembly holding an objective lens and provided with a coil bobbin, elastic supporting devices which support the moving assembly along the focusing dimension and the tracking dimension, focusing coils and tracking coils wound on the coil bobbin, and a magnetic circuit formed by a yoke and a magnet. The center of gravity of the moving assembly is positioned so that the product of the distance from an effective section of the focusing coil to the center of gravity of the moving assembly and the force produced at the effective section is about equal to the product of the distance from a noneffective section of the focusing coil to the center of gravity of the moving assembly and the force produced at the noneffective section.