Abstract: An optical pickup device includes a plurality of laser light sources emitting laser beams of different oscillation wavelengths, and a plurality of objective lenses on which the laser beams in the form of diverging beams emitted by the plurality of laser light sources are incident, and which directly focus the laser beams onto a recording surface of an optical disc. A rising mirror reflects a laser beam in the form of a diverging beam emitted by a laser light source of a predetermined oscillation wavelength among the plurality of laser light sources so as to lead the laser beam to one of the plurality of objective lenses, and transmits the laser beam in the form of a diverging beam emitted by the other laser light source. As the rising mirror transmits the laser beam in the form of the diverging beam emitted by said other laser light source, astigmatism is generated so as to correct existing astigmatism of the laser beam emitted by said other laser light source.

Abstract: An objective lens driving device includes a lens holder (3) holding an objective lens (1, 2), a stationary part (5) that supports the lens holder (3) via wires (7a, 7b), an electromagnetic coil (11a-11d, 12a-12d) provided on the lens holder, and a magnet (4a, 4b) provided on the stationary part and magnetized in a multipolar manner so that different magnetic pole surfaces are arranged on a surface of the magnet facing the electromagnetic coil. The lens holder has a convex portion (16a-16d, 17a-17d) on a surface thereof facing the magnet. The convex portion has at least one groove (601-604, 701-704) portion extending parallel to a direction of magnetic flux lines of the magnet facing the convex portion, and at least a surface of the convex portion is formed of material having magnetic property.

Abstract: An optical pickup device includes an objective lens (1) for focusing a light flux onto an information layer of a disk-shaped medium, an objective lens driving unit that drives the objective lens (1) in a focus servo direction and in a tracking servo direction, a correction lens (14) disposed on the same optical axis as the objective lens (1), and a correction lens driving unit that drives the correction lens (14) in the same direction as the focus servo direction to control the condition of the light flux incident on the objective lens.

Abstract: An optical-system driving device is achieved that can switch over between objective lenses and is space-saving, lightweight, and simply-configured. An optical-system driving device for recording information onto or playing it back from an optical storage medium, includes a stationary unit having a rotation axis; a movable unit pivotable about the rotation axis; pivotal movement means for pivotally moving the movable unit about the rotation axis; and the movable unit includes a holder having a plurality of optical means that is able to focus a beam of light onto the optical storage medium, and a plurality of conductive elastic members for supporting the holder, wherein an optical axis of each of the plurality of optical means is located substantially equidistant from the rotation axis, and the optical means for focusing the beam of light onto the optical storage medium is selected by pivotally moving the movable unit with the rotation means.

Abstract: In a method of setting a quantity of light directed onto an optical disc for reproduction purposes, an area of the optical disc in which information has been recorded is reproduced with a test-reproducing light quantity (S14, S24), a reproduction time or number of reproductions up to the time when the reproduced signal quality value reaches a prescribed value is determined (S20, S30), and the quantity of reproducing light used in regular reproduction is set by performing calculations with the determined value (S32). The state in which recorded marks have significantly degraded can also be detected, and degradation of the recorded marks to the unreproducible state can be avoided.

Abstract: An optical element driving apparatus includes a holder that holds a plurality of switchable optical elements for focusing light on a recording medium, a resiliently deformable supporting unit that supports the holder, a focusing driving unit that drives the holder in a direction of optical axes of the optical elements, and a tracking driving unit that drives the holder in a tracking direction perpendicular to the direction of the optical axes. The switching of the optical elements is performed by moving the holder by means of the tracking driving unit, so as to select one of the optical elements that focuses light on the recording medium.

Abstract: A lens driving device according to the present invention includes a mounting base; a collimation lens that is engaged with the mounting base and movable in optical axis directions; and a driving source that moves the collimation lens in the optical axis directions, and the mounting base includes a fulcrum section with which, when the driving device is mounted on a base, a pitch angle and a roll angle of the driving device are adjusted with respect to the base and the optical axis.

Abstract: A light wavefront measuring apparatus (2, 2a, 42) includes a separating element (7a, 47a) for separating a flux of light which exits from an optical head (1, 31) into a first beam and a second beam, a first interference fringe display section (21, 21a) for displaying interference fringes formed from the first beam, a Dove prism (13, 53) for rotating a wavefront of the second beam around its optical axis (AX2), and a second interference fringe display section (22, 22a) for displaying interference fringes formed from the second beam which passed through it. In adjustment of the light source device, position of a collimator (5) in the optical head (1, 31) is adjusted in optical axis direction so as to approximate the interference fringe patterns displayed in the interference fringe display sections (21, 22, 21a, 22a) each other.

Abstract: A lens driving device according to the present invention includes a mounting base; a collimation lens that is engaged with the mounting base and movable in optical axis directions; and a driving source that moves the collimation lens in the optical axis directions, and the mounting base includes a fulcrum section with which, when the driving device is mounted on a base, a pitch angle and a roll angle of the driving device are adjusted with respect to the base and the optical axis.

Abstract: An optical element driving apparatus includes a holder that holds a plurality of switchable optical elements for focusing light on a recording medium, a resiliently deformable supporting unit that supports the holder, a focusing driving unit that drives the holder in a direction of optical axes of the optical elements, and a tracking driving unit that drives the holder in a tracking direction perpendicular to the direction of the optical axes. The switching of the optical elements is performed by moving the holder by means of the tracking driving unit, so as to select one of the optical elements that focuses light on the recording medium.

Abstract: An optical pickup device includes an objective lens (1) for focusing a light flux onto an information layer of a disk-shaped medium, an objective lens driving unit that drives the objective lens (1) in a focus servo direction and in a tracking servo direction, a correction lens (14) disposed on the same optical axis as the objective lens (1), and a correction lens driving unit that drives the correction lens (14) in the same direction as the focus servo direction to control the condition of the light flux incident on the objective lens.

Abstract: A light wavefront measuring apparatus (2, 2a, 42) includes a separating element (7a, 47a) for separating a flux of light which exits from an optical head (1, 31) into a first beam and a second beam, a first interference fringe display section (21, 21a) for displaying interference fringes formed from the first beam, a Dove prism (13, 53) for rotating a wavefront of the second beam around its optical axis (AX2), and a second interference fringe display section (22, 22a) for displaying interference fringes formed from the second beam which passed through it. In adjustment of the light source device, position of a collimator (5) in the optical head (1, 31) is adjusted in optical axis direction so as to approximate the interference fringe patterns displayed in the interference fringe display sections (21, 22, 21a, 22a) each other.

Abstract: An optical recording and reproducing apparatus uses a laser to form one or more spots on an information recording medium preformatted with wobbling guide grooves, and detects tracking error. If the differential push-pull method of detecting tracking error is used, a center spot is flanked by satellite spots distant by an odd multiple of half the repeating period of tile wobble. If the three-beam method is used, the distance is an odd multiple of one-fourth the repeating period of the wobble. If the push-pull method is used, a split photodetector generates a pair of electrical signals. The sum and difference of these signals are filtered, then synchronously detected, and the result is combined with the difference signal to generate a corrected tracking error signal.

Abstract: An optical recording and reproducing apparatus uses a laser to form one or more spots on an information recording medium preformatted with wobbling guide grooves, and detects tracking error. If the differential push-pull method of detecting tracking error is used, a center spot is flanked by satellite spots distant by an odd multiple of half time repeating period of tile wobble. If tile three-beam method is used, the distance is an odd multiple of one-fourth the repeating period of the wobble. If the push-pull method is used, a split photodetector generates a pair of electrical signals. The sum and difference of these signals are filtered, then synchronously detected, and the result is combined with the difference signal to generate a corrected tracking error signal.

Abstract: An optical recording and reproducing apparatus uses a laser to form one or more spots on an information recording medium preformatted with wobbling guide grooves, and detects tracking error. If the differential push-pull method of detecting tracking error is used, a center spot is flanked by satellite spots distant by an odd multiple of half the repeating period of the wobble. If the three-beam method is used, the distance is an odd multiple of one-fourth the repeating period of the wobble. If the push-pull method is used, a split photodetector generates a pair of electrical signals. The sum and difference of these signals are filtered, then synchronously detected, and the result is combined with the difference signal to generate a corrected tracking error signal.

Abstract: An objective lens driving device with a multipole magnet which includes a cylindrical yoke with an E-shaped cross section for defining an annular gap between the central yoke section and the outer cyclindrical yoke section; four rectangular tracking coils attached to the side of a focusing coil such that a pair of vertical coil sides of each tracking coil are parallel to a supporting shaft; and a pair of circular multipole magnets disposed within the gap between the central and outer cylindrical yoke sections and each having at least three magnet sections, with opposite end magnet sections having a polarity opposite to that of the central magnet section so that the vertical coil sides interlink with magnetic fluxes having opposite directions to each other, whereby tracking forces act upon the vertical coil sides in the same direction.